Salmonella

Int Immunol, 2002 Feb, 14(2), 111 - 9
A quantitative model for neutrophil response and delayed-type hypersensitivity reaction in rats orally inoculated with various doses of Salmonella Enteritidis; Takumi K et al.; Our aim was to investigate the quantitative relationship between inoculation doses and physiological responses to infection by Salmonella enterica serovar Enteritidis . Rats were orally inoculated with 10-10(9) c.f.u . of S . Enteritidis and monitored for 6 days . Neutrophil and delayed-type hypersensitivity (DTH) responses were assessed, and the spleens were analyzed for the pathogen . The experimental data were analyzed by a mathematical model for the host response to salmonella infection, which is based on the assumptions that: (i) the number of pathogens in the inoculum is Poisson distributed, (ii) any cell that is inoculated can multiply and form a clone to infect the animal, (iii) the probability of infection by any cell of the pathogen is independent of the number of cells ingested, and (iv) the magnitude of the immune response increases with dose, but eventually saturates to a maximum level . The probability of infection assessed by the DTH response is 7.5 x 10(-3)/c.f.u . of the inoculum (confidence interval 5.1 x 10(-5), 1.2 x 10(-2)) . When five S . Enteritidis independently initiated the infection, the DTH response to the resulting clones of the salmonellae saturated to the maximum level . The probability of infection assessed by the neutrophil response is 3.4 x 10(-4)/c.f.u . (1.0 x 10(-4), 6.8 x 10(-4)) . The response saturated when six S . Enteritidis independently initiated the infection . The probability of infection assessed by the analysis of spleens is 1.2 x 10(-3)/c.f.u . (4.1 x 10(-4), 2.6 x 10(-3)) . We conclude that at low inocula, infections are initiated by very small numbers of bacteria . The magnitude of the immune responses is similar whether only a few or a larger number of bacteria initiated the infection.

J Food Prot, 2002 Jan, 65(1), 53 - 60
Thermal inactivation D- and z-values of Salmonella serotypes and listeria innocua in chicken patties, chicken tenders, franks, beef patties, and blended beef and turkey patties; Murphy RY et al.; Commercially formulated meat products, including chicken patties, chicken tenders, franks, beef patties, and blended beef and turkey patties, were obtained from processors . Each product was inoculated with 7 to 8 logs of Salmonella (Senftenberg, Typhimurium, Heidelberg, Mission, Montevideo, and California) or Listeria innocua . The inoculated meat samples were heat treated at 55 to 70 degrees C . At each temperature, the decimal reduction time (D) was obtained by linear regression of survival curves . Values of D and the temperature difference required for the thermal inactivation curve to drop a logarithmic cycle (z) were determined for the Salmonella serotypes and L . innocua in each product . At 55 to 70 degrees C . for the five tested products, the D-values for the Salmonella serotypes and L . innocua were 26.97 to 0.25 min and 191.94 to 0.18 min, respectively, and their z-values were 7.60 to 9.83 degrees C and 4.86 to 8.67 degrees C, respectively . Significant differences were found for the D- and z-values among the five products . This study will better enable processors to determine the process lethality of pathogens in commercial meat products.

J Food Prot, 2002 Jan, 65(1), 100 - 5
Inactivation of Escherichia coli O157:H7, Salmonella enteritidis, and Listeria monocytogenes on apples, oranges, and tomatoes by lactic acid with hydrogen peroxide; Venkitanarayanan KS et al.; The objective of this study was to develop a practical and effective method for inactivating or substantially reducing Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes on apples, oranges, and tomatoes . Apples, oranges, and tomatoes were spot-inoculated with five-strain mixtures of E . coli O157:H7, Salmonella Enteritidis, and L . monocytogenes near the stem end and were submerged in sterile deionized water containing 1.5% lactic acid plus 1.5% hydrogen peroxide for 15 min at 40 degrees C . Inoculated samples treated with sterile deionized water at the same temperature and for the same duration served as controls . The bacterial pathogens on fruits subjected to the chemical treatment were reduced by >5.0 log10 CFU per fruit, whereas washing in deionized water decreased the pathogens by only 1.5 to 2.0 log10 CFU per fruit . Furthermore, substantial populations of the pathogens survived in the control wash water, whereas no E . coli O157:H7, Salmonella Enteritidis, or L . monocytogenes cells were detected in the chemical treatment solution . The sensory and qualitative characteristics of apples treated with the chemical wash solution were not adversely affected by the treatment . It was found that the treatment developed in this study could effectively be used to kill E . coli O157:H7, Salmonella Enteritidis, and L . monocytogenes on apples, oranges, and tomatoes at the processing or packaging level.

Acta Crystallogr D Biol Crystallogr, 2002 Feb, 58(Pt 2), 306 - 9 Epub 2002 Jan 24.
Pentaerythritol propoxylate: a new crystallization agent and cryoprotectant induces crystal growth of 2-methylcitrate dehydratase; Gulick AM et al.; In the search for macromolecular crystallization conditions, the precipitant is probably the most important variable, such that when problematic crystals are encountered there is always the question of whether an alternative precipitant might resolve the problem . During an effort to obtain high-quality crystals of several problematic proteins, two new agents, pentaerythritol propoxylate and pentaerythritol ethoxylate, yielded well ordered quality crystals where more traditional precipitants were unsuccessful . Pentaerythritol propoxylate and pentaerythritol ethoxylate contain a pentaerythritol backbone to which organic polymers are bound, forming a branched polymer . As such, they are larger than small organic precipitants such as low molecular-weight alcohols or 2-methyl-2,4-pentanediol, but behave differently to polyethylene glycols . These compounds have been used to crystallize an enzyme encoded by the Salmonella enterica prpD gene that catalyzes the dehydration of 2-methylcitrate to form 2-methyl-cis-aconitate . While the PrpD protein has crystallized readily under a number of conditions, the resultant crystals were unsuitable for a crystal structure determination . The new crystals obtained with 25-40% pentaerythritol propoxylate belong to the orthorhombic space group C222(1), with unit-cell parameters a = 73.2, b = 216.4, c = 214.3 A, and diffract beyond 2.0 A with synchrotron radiation . A further benefit of this precipitant for crystallization is its ability to function as a cryoprotectant, allowing the crystals to be transferred directly from the mother liquor to the nitrogen stream at 113 K.

J Bacteriol, 2002 Feb, 184(4), 1209 - 13
FimZ is a molecular link between sticking and swimming in Salmonella enterica serovar Typhimurium; Clegg S et al.; Salmonella enterica serovar Typhimurium produces two types of filamentous appendages on its surface . Fimbriae mediate adherence to tissues and cells via receptor-specific interactions, and flagella are the organelles of motility . These appendages play a role in colonization and dissemination, respectively, from infected surfaces and may be important components of bacterial survival . Increased expression of FimZ in serovar Typhimurium resulted in bacteria which were hyperfimbriated but were nonmotile in soft agar . This lack of motility was associated with down regulation of the flhDC master flagellar operon . Therefore, FimZ represents a molecular connection between flagella and fimbrial formation in serovar Typhimurium, indicating that the synthesis of flagella and fimbriae are oppositely controlled.

J Bacteriol, 2002 Feb, 184(4), 992 - 1002
Transposable element ISHp608 of Helicobacter pylori: nonrandom geographic distribution, functional organization, and insertion specificity; Kersulyte D et al.; A new member of the IS605 transposable element family, designated ISHp608, was found by subtractive hybridization in Helicobacter pylori . Like the three other insertion sequences (ISs) known in this gastric pathogen, it contains two open reading frames (orfA and orfB), each related to putative transposase genes of simpler (one-gene) elements in other prokaryotes; orfB is also related to the Salmonella virulence gene gipA . PCR and hybridization tests showed that ISHp608 is nonrandomly distributed geographically: it was found in 21% of 194 European and African strains, 14% of 175 Bengali strains, 43% of 131 strains from native Peruvians and Alaska natives, but just 1% of 223 East Asian strains . ISHp608 also seemed more abundant in Peruvian gastric cancer strains than gastritis strains (9 of 14 versus 15 of 45, respectively; P = 0.04) . Two ISHp608 types differing by approximately 11% in DNA sequence were identified: one was widely distributed geographically, and the other was found only in Peruvian and Alaskan strains . Isolates of a given type differed by < or = 2% in DNA sequence, but several recombinant elements were also found . ISHp608 marked with a resistance gene was found to (i) transpose in Escherichia coli; (ii) generate simple insertions during transposition, not cointegrates; (iii) insert downstream of the motif 5"-TTAC without duplicating target sequences; and (iv) require orfA but not orfB for its transposition . ISHp608 represents a widespread family of novel chimeric mobile DNA elements whose further analysis should provide new insights into transposition mechanisms and into microbial population genetic structure and genome evolution.

Zentralbl Chir, 2001 Dec, 126(12), 982 - 8
{Mycotic aneurysms--A retrospective analysis}; Klein F et al.; 12 patients (10 males and 2 females, average age 53 years) were operated upon in our hospital between 1994 and 1999 for mycotic aneurysms . The aneurysms were located in 7 patients in the aorto-iliac segment, 5 patients were treated for peripheral or visceral aneurysms . Two of these patients suffered from multiple aneurysms . When peripheral arteries were affected, a pulsatile tumour was felt . Most of these tumours developed in a relatively short period of time and sometimes a perivascular inflammation occurred . This was not the case when central arteries were attacked . A septic process or an infection, for example salmonella-enteritis, often preceded shortly the development of a mycotic aneurysm . In the case of an aneurysm of the aorto-iliac section we consider an in situ reconstruction with alloplastic material in combination with a perivascular debridement, lavage and omentum majus plastic as the treatment of choice . In peripheral arteries reconstruction should be performed with autologous vessels . Depending on the local findings, a perivascular debridement should also be performed in these cases . The reconstruction always should be combined with a calculated antibiotic therapy . Two of our patients died perioperatively . During follow up, 8 patients showed patent reconstructions and no signs of infection . The urgency of surgery depends on the level of inflammation and the existence of any secondary complications.

J Agric Food Chem, 2002 Jan 30, 50(3), 610 - 7
Antioxidant and antimutagenic properties of aqueous extract of date fruit (Phoenix dactylifera L . Arecaceae); Vayalil PK; Fruits of the date palm (Phoenix dactylifera L . Arecaceae) are very commonly consumed in many parts of the world and are a vital component of the diet in most of the Arabian countries . This preliminary study documents for the first time its antioxidant and antimutagenic properties in vitro . There was a dose-dependent inhibition of superoxide and hydroxyl radicals by an aqueous extract of date fruit . The amount of fresh extract required to scavenge 50% of superoxide radicals was equivalent to 0.8 mg/mL of date fruit in the riboflavin photoreduction method . An extract of 2.2 mg/mL of date fruit was needed for 50% hydroxyl-radical-scavenging activity in the deoxyribose degradation method . Concentrations of 1.5 and 4.0 mg/mL completely inhibited superoxide and hydroxyl radicals, respectively . Aqueous date extract was also found to inhibit significantly the lipid peroxidation and protein oxidation in a dose-dependent manner . In an Fe(2+)/ascorbate system, an extract of 1.9 mg/mL of date fruit was needed for 50% inhibition of lipid peroxides . In a time course inhibition study of lipid peroxide, at a 2.0 mg/mL concentration of date extract, there was a complete inhibition of TBARS formation in the early stages of the incubation period that increased during later stages of the incubation . Similarly, in the high Fe(2+)/ascorbate induction system a concentration of 2.3 mg/mL inhibited carbonyl formation measured by DNPH reaction by 50% . Moreover, a concentration of 4.0 mg/mL completely inhibited lipid peroxide and protein carbonyl formation . Date fruit extract also produced a dose-dependent inhibition of benzo(a)pyrene-induced mutagenecity on Salmonella tester strains TA-98 and TA-100 with metabolic activation . Extract from 3.6 mg/plate and 4.3 mg/plate was found required for 50% inhibition of His+ revertant formation in TA-98 and TA-100, respectively . These results indicate that antioxidant and antimutagenic activity in date fruit is quite potent and implicates the presence of compounds with potent free-radical-scavenging activity.

Water Sci Technol, 2001, 44(11-12), 345 - 52
Residential subsurface flow treatment wetlands in northern Minnesota; Axler R et al.; Approximately 30% of Minnesotans use on-site systems (approximately 500,000 residences) and >50% are failing or non-compliant with regulations due to restrictive soils and site conditions . Many sites occur near lakes and streams creating health hazards and deteriorating water quality . SSF CWs have been evaluated year-round at two northern sites since 1995 . The NERCC CWs simulate single homes and the Grand Lake demonstration CW treats STE from a cluster of 9 lakeshore homes . Systems were generally able to achieve design criteria of 25 mg TSS/L and 30 mg BOD5/L and the NERCC CWs required only 0.3 m of unsaturated soil to achieve consistent disinfection to <200 fecals/100 mL year round . Seeding experiments with Salmonella indicated removal efficiencies of 99.8% in summer and 95% in winter . High strength (approximately 300 mg BOD/L, 95 mg TN/L) influent at NERCC probably limited system performance, particularly N-removal (mass) which was approximately 42% in summer and 20% in winter . The data indicate CW's are a viable, year-round treatment option for homeowners in terms of performance, ease of operation, and cost but require additional maintenance related to inconsistent vegetation growth, winter insulation, and meeting concentration-based regulatory standards since they were seasonally and annually variable due to rain events, partial freezing, spring snowmelt, and summer evapotranspiration.

J Med Microbiol, 2002 Jan, 51(1), 13 - 9
Elimination of Salmonella enterica serotype enteritidis in intestinal epithelial cells by mechanisms other than nitric oxide; Saarinen M et al.; Production of nitric oxide (NO) by intestinal epithelial cells is induced after infection with Salmonella spp . or some other enteroinvasive bacteria . However, direct evidence of the role of NO in the elimination of intracellular pathogens in intestinal mucosa has not been established . This study investigated whether NO mediates killing of Salmonella enterica serovar Enteritidis in human intestinal epithelial cells by using parent Henle-407 cell line and a transfected cell line not capable of induced NO production (Henle-NO(def)) . NO synthesis was studied as combined accumulation of nitrite and nitrate, as inducible nitric oxide synthase (iNOS) protein determined by Western blotting and as iNOS mRNA detected by reverse transcription (RT)-PCR . Although parent and Henle-NO(def) cells differed markedly in their ability to produce NO after infection, they eliminated S . Enteritidis equally, as determined by cfu counts . The presence of aminoguanidine, a selective iNOS inhibitor, during the infection blocked the production of NO but did not affect the elimination of the bacteria . These data suggest that NO does not have a direct role in the elimination of intracellular Salmonellae by human intestinal epithelial cells.

Res Vet Sci, 2001 Dec, 71(3), 155 - 9
Antibacterial activity of raspberry cordial in vitro; Ryan T et al.; Raspberry juice cordial has a long anecdotal use in Australia for the prophylaxis and treatment of gastroenteritis in livestock, cage birds and humans . The antimicrobial properties of raspberry juice cordial, raspberry juice, raspberry leaf extract and a commercial brand of raspberry leaf tea were investigated against five human pathogenic bacteria and two fungi . Raspberry cordial and juice were found to significantly reduce the growth of several species of bacteria, including Salmonella, Shigella and E . coli, but demonstrated no antifungal activity . No antimicrobial activity was detected in the leaf extract or tea .

J Infect, 2001 Oct, 43(3), 169 - 72
Epidemiological analysis of Salmonella enteritidis isolates in Singapore; Ling ML et al.; OBJECTIVES: Salmonella enteritidis is the most common non-typhoidal Salmonella species isolated in Singapore causing gastroenteritis and occasional bacteremia with secondary complications . The number of S . enteritidis isolates rose in 1993 and since then, it was the commonest Salmonella sp . isolated . In 1997, a total of 139 S . enteritidis was isolated and this comprised 19.2% of all non-typhoidal Salmonella sp . isolated . METHODS: We studied the antimicrobial susceptibilities, phage types and molecular epidemiology of 89 of these S . enteritidis strains . Fifty per cent were stool isolates whilst 33.3% were isolated from blood samples . RESULTS: All the isolates were susceptible to cephalothin, ceftriaxone, ciprofloxacin, aztreonam, gentamicin, amikacin, kanamycin, neomycin, streptomycin and nalidixic acid; whilst 75.3% were resistant to sulphonamide, 15.7% to tetracycline, 7.9% to co-trimoxazole, 6.7% to trimethoprim, 2.2% to ampicillin and 2.2% to chloramphenicol . The most frequent phage types were phage type 4 (64%), followed by phage type 1 (12.4%) and phage type 8 (2.2%) . Seventy four of the 89 (83.1%) S . enteritidis isolates analysed by pulsed-field gel electrophoresis showed an indistinguishable pattern A when digested by restriction enzyme Xba I suggesting the presence of a predominant clone of S . enteritidis circulating in Singapore in 1997 .

Nature, 2002 Jan 17, 415(6869), 287 - 94
X-ray structure of a ClC chloride channel at 3.0 A reveals the molecular basis of anion selectivity; Dutzler R et al.; The ClC chloride channels catalyse the selective flow of Cl- ions across cell membranes, thereby regulating electrical excitation in skeletal muscle and the flow of salt and water across epithelial barriers . Genetic defects in ClC Cl- channels underlie several familial muscle and kidney diseases . Here we present the X-ray structures of two prokaryotic ClC Cl- channels from Salmonella enterica serovar typhimurium and Escherichia coli at 3.0 and 3.5 A, respectively . Both structures reveal two identical pores, each pore being formed by a separate subunit contained within a homodimeric membrane protein . Individual subunits are composed of two roughly repeated halves that span the membrane with opposite orientations . This antiparallel architecture defines a selectivity filter in which a Cl- ion is stabilized by electrostatic interactions with alpha-helix dipoles and by chemical coordination with nitrogen atoms and hydroxyl groups . These findings provide a structural basis for further understanding the function of ClC Cl- channels, and establish the physical and chemical basis of their anion selectivity.

Infect Immun, 2002 Feb, 70(2), 1027 - 31
Urease of enterohemorrhagic Escherichia coli: evidence for regulation by fur and a trans-acting factor; Heimer SR et al.; Recent genomic analyses of Escherichia coli O157:H7 strain EDL933 revealed two loci encoding urease gene homologues (ureDABCEFG), which are absent in nonpathogenic E . coli strain K-12 . This report demonstrates that the cloned EDL933 ure gene cluster is capable of synthesizing urease in an E . coli DH5alpha background . However, when the gene fragment is transformed back into the native EDL933 background, the enzymatic activity of the cloned determinants is undetectable . We speculate that an unidentified trans-acting factor in enterohemorrhagic E . coli (EHEC) is responsible for this regulation of ure expression . In addition, Fur-like recognition sites are present in three independent O157:H7 isolates upstream of ureD and ureA . Enzymatic assays confirmed a difference in urease expression of cloned EHEC ure clusters in E . coli MC3100Deltafur . Likewise, interruption of fur in O157:H7 isolate IN1 significantly diminished urease activity . We propose that, similar to the function of Fur in regulating the acid response of Salmonella enterica serovar Typhimurium, it modulates urease expression in EHEC, perhaps contributing to the acid tolerance of the organism.

Infect Immun, 2002 Feb, 70(2), 964 - 9
Nitric oxide and apoptosis induced in Peyer's patches by attenuated strains of Salmonella enterica serovar Enteritidis; Cerquetti MC et al.; Nitric oxide (NO) is a toxic molecule of the immune system which contributes to the control of microbial pathogens . Additional functions of NO in innate and adaptive immunity have recently been described; these functions include the modulation of the cytokine response of lymphocytes and the regulation of immune cell apoptosis . In addition to direct microbicidal actions, NO has immunoregulatory effects relevant to the control of infections . In turn, infected macrophages and macrophage-regulating lymphocytes may undergo apoptosis during infection by Salmonella spp . In this work we investigated the ability of attenuated strains of Salmonella enterica serovar Enteritidis with different protective capacities to induce intestinal inducible nitric oxide synthase (iNOS) and apoptosis in Peyer's patches (PP) in mice . Results showed that the intestinal iNOS activity correlated with increased apoptosis in PP . Furthermore, the ability to induce intestinal NO production and apoptosis within the first few hours after immunization seemed to correlate with the protective capacity of mutant E/1/3 of S . enterica serovar Enteritidis . It was found that nonprotective mutant C/2/2, which was unable to induce intestinal NO production, also failed to induce apoptosis in PP . Moreover, aminoguanidine treatment at the time of immunization resulted in inhibition of the NO production and apoptosis induced by protective mutant E/1/3 and completely abolished protection against challenge . These results suggest that the induction of iNOS in the intestinal mucosa by attenuated mutant E/1/3 of S . enterica serovar Enteritidis at the time of immunization is necessary to generate a protective immune response.

Infect Immun, 2002 Feb, 70(2), 953 - 63
Cell differentiation is a key determinant of cathelicidin LL-37/human cationic antimicrobial protein 18 expression by human colon epithelium; Hase K et al.; Antimicrobial peptides are highly conserved evolutionarily and are thought to play an important role in innate immunity at intestinal mucosal surfaces . To better understand the role of the antimicrobial peptide human cathelicidin LL-37/human cationic antimicrobial protein 18 (hCAP18) in intestinal mucosal defense, we characterized the regulated expression and production of this peptide by human intestinal epithelium . LL-37/hCAP18 is shown to be expressed within epithelial cells located at the surface and upper crypts of normal human colon . Little or no expression was seen within the deeper colon crypts or within epithelial cells of the small intestine . Paralleling its expression in more differentiated epithelial cells in vivo, LL-37/hCAP18 mRNA and protein expression was upregulated in spontaneously differentiating Caco-2 human colon epithelial cells and in HCA-7 human colon epithelial cells treated with the cell differentiation-inducing agent sodium butyrate . LL-37/hCAP18 expression by colon epithelium does not require commensal bacteria, since LL-37/hCAP18 is produced with a similar expression pattern by epithelial cells in human colon xenografts that lack a luminal microflora . LL-37/hCAP18 mRNA was not upregulated in response to tumor necrosis factor alpha, interleukin 1alpha (IL-1alpha), gamma interferon, lipopolysaccharide, or IL-6, nor did the expression patterns and levels of LL-37/hCAP18 in the epithelium of the normal and inflamed colon differ . On the other hand, infection of HCA-7 cells with Salmonella enterica serovar Dublin or enteroinvasive Escherichia coli modestly upregulated LL-37/hCAP18 mRNA expression . We conclude that differentiated human colon epithelium expresses LL-37/hCAP18 as part of its repertoire of innate defense molecules and that the distribution and regulated expression of LL-37/hCAP18 in the colon differs markedly from that of other enteric antimicrobial peptides, such as defensins.

Infect Immun, 2002 Feb, 70(2), 606 - 11
The Helicobacter pylori homologue of the ferric uptake regulator is involved in acid resistance; Bijlsma JJ et al.; The only known niche of the human pathogen Helicobacter pylori is the gastric mucosa, where large fluctuations of pH occur, indicating that the bacterial response and resistance to acid are important for successful colonization . One of the few regulatory proteins in the H . pylori genome is a homologue of the ferric uptake regulator (Fur) . In most bacteria, the main function of Fur is the regulation of iron homeostasis . However, in Salmonella enterica serovar Typhimurium, Fur also plays an important role in acid resistance . In this study, we determined the role of the H . pylori Fur homologue in acid resistance . Isogenic fur mutants were generated in three H . pylori strains (1061, 26695, and NCTC 11638) . At pH 7 there was no difference between the growth rates of mutants and the parent strains . Under acidic conditions, growth of the fur mutants was severely impaired . No differences were observed between the survival of the fur mutant and parent strain 1061 after acid shock . Addition of extra iron or removal of iron from the growth medium did not improve the growth of the fur mutant at acidic pH . This indicates that the phenotype of the fur mutant at low pH was not due to increased iron sensitivity . Transcription of fur was repressed in response to low pH . From this we conclude that Fur is involved in the growth at acidic pH of H . pylori; as such, it is the first regulatory protein implicated in the acid resistance of this important human pathogen.

Infect Immun, 2002 Feb, 70(2), 558 - 68
Porins from Salmonella enterica serovar Typhimurium activate the transcription factors activating protein 1 and NF-kappaB through the Raf-1-mitogen-activated protein kinase cascade; Galdiero M et al.; In this study we examined the ability of Salmonella enterica serovar Typhimurium porins to activate activating protein 1 (AP-1) and nuclear factor kappaB (NF-kappaB) through the mitogen-activated protein kinase (MAPK) cascade, and we identified the AP-1-induced protein subunits . Our results demonstrate that these enzymes may participate in cell signaling pathways leading to AP-1 and NF-kappaB activation following porin stimulation of cells . Raf-1 was phosphorylated in response to the treatment of U937 cells with porins; moreover, the porin-mediated increase in Raf-1 phosphorylation is accompanied by the phosphorylation of MAPK kinase 1/2 (MEK1/2), p38, extracellular-signal-regulated kinase 1/2, and c-Jun N-terminal kinase . We used three different inhibitors of phosphorylation pathways: 2'-amino-3'-methoxyflavone (PD-098059), a selective inhibitor of MEK1 activator and the MAPK cascade; 4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole (SB203580), a specific inhibitor of the p38 pathway; and 7beta-acetoxy-1alpha,6beta,9alpha-trihydroxy-8,13-epoxy-labd-14-en-11-one (forskolin), an inhibitor at the level of Raf-1 kinase . PD-098059 pretreatment of cells decreases AP-1 and NF-kappaB activation by lipopolysaccharide (LPS) but not by porins, and SB203580 pretreatment of cells decreases mainly AP-1 and NF-kappaB activation by porins; in contrast, forskolin pretreatment of cells does not affect AP-1 and NF-kappaB activation following either porin or LPS stimulation . Our data suggest that the p38 signaling pathway mainly regulates AP-1 and NF-kappaB activation in cells treated with S . enterica serovar Typhimurium porins . Antibody electrophoretic mobility shift assays showed that JunD and c-Fos binding is found in cells treated with porins, in cells treated with LPS, and in unstimulated cells . However, by 30 to 60 min of stimulation, a different complex including c-Jun appears in cells treated with porins or LPS, while the Fra-2 subunit is present only after porin stimulation . These data suggest different molecular mechanisms of activation induced by porins or by LPS.

Infect Immun, 2002 Feb, 70(2), 551 - 7
Increased susceptibility of C1q-deficient mice to Salmonella enterica serovar Typhimurium infection; Warren J et al.; The role of the complement system in host defense against Salmonella infection is poorly defined . Bacterial cell wall O-antigen polysaccharide can activate the alternative pathway in vitro . No studies, however, have elucidated the role of the classical pathway in immunity to Salmonella spp . in vivo . C1q-deficient mice (C1qa(-/-)) on a 129/Sv genetic background and strain-matched controls were infected intraperitoneally and intravenously with Salmonella enterica serovar Typhimurium and monitored over a 14-day period . After inoculation by either route, the C1qa(-/-) mice were found to be significantly more susceptible to Salmonella infection . Hepatic and splenic bacterial counts, performed at various time points, showed increased numbers of colonies in complement-deficient mice compared to controls . Analysis of blood clearance showed no difference between the two experimental groups during the first 15 min . However, after 20 min and until 6 h postinfection, numbers of circulating bacteria were significantly higher in complement-deficient mice . In vitro experiments using either resident or thioglycolate-elicited peritoneal macrophages showed a significant increase in the number of bacteria inside C1q-deficient macrophages compared to controls irrespective of the serum used for opsonizing the bacteria . These findings could not be explained either by an increased bacterial uptake, analyzed in vitro and in vivo using green fluorescent protein-tagged salmonellae, or by a defect in the respiratory burst or in NO production . The data presented here suggest the possibility of novel pathways by which C1q may modulate the pathogenesis of infectious diseases caused by intracellular pathogens.

Infect Immun, 2002 Feb, 70(2), 451 - 61
The global regulator ArcA controls resistance to reactive nitrogen and oxygen intermediates in Salmonella enterica serovar Enteritidis; Lu S et al.; Salmonella enterica serovar Enteritidis is a major cause of food-borne diseases associated with consumption of shell eggs . Clinical isolates of S . enterica serovar Enteritidis exhibit a wide spectrum of virulence in mice . A highly virulent isolate (SE2472) was previously shown to be more resistant in vitro than other clinical isolates to acidified sodium nitrite (ASN), a generator of reactive nitrogen and oxygen intermediates (RNI/ROI) . SE2472 is also more resistant to S-nitrosoglutathione (GSNO) and hydrogen peroxide (H(2)O(2)) than an ASN-susceptible isolate of S . enterica serovar Enteritidis (SE8743) . To investigate the molecular basis for the RNI/ROI resistance of S . enterica serovar Enteritidis, we transformed a genomic DNA library of SE2472 into SE8743 . A plasmid clone conferred upon SE8743 enhanced resistance to ASN, GSNO, and H(2)O(2) . The DNA insert in the clone encoded ArcA, a global regulator . An arcA mutant of SE2472 was constructed and was found to be more susceptible to GSNO and hydrogen peroxide but not more susceptible to ASN than wild-type SE2472 . The susceptibility of the arcA mutant to GSNO and H(2)O(2) was complemented by a plasmid harboring arcA . The coding sequence of the arcA gene in SE2472 and the coding sequence of the arcA gene in SE8743 were identical, suggesting that the difference in resistance to RNI/ROI maybe due to the activity of genes regulated by ArcA . No significant difference in virulence between the wild type and the arcA mutant of SE2472 was observed in mice . These observations show that arcA is essential for resistance of S . enterica serovar Enteritidis to nitrosative and oxidative stress . However, additional genetic loci may contribute to the resistance to RNI/ROI and unusually high virulence for mice of SE2472.

Antimicrob Agents Chemother, 2002 Feb, 46(2), 360 - 6
Molecular cloning and characterization of the Salmonella enterica Serovar Paratyphi B rma Gene, which confers multiple drug resistance in Escherichia coli; Yassien MA et al.; A genomic library from a strain of Salmonella enterica serovar Paratyphi B that exhibits multiple drug resistance (MDR) was constructed in Escherichia coli . Two of the recombinant plasmids, pNOR5 and pNOR5, conferred resistance only to fluoroquinolones in E . coli, whereas the third, pNCTR4, conferred the MDR phenotype . Sequence and subcloning analysis showed that it is the presence of RecA on the first two plasmids which confers resistance to fluoroquinolones in E . coli . A similar analysis established that the MDR phenotype conferred by pNCTR4 is due to a gene, rma (resistance to multiple antibiotics), which encodes a 13.5-kDa polypeptide . The derived sequence for Rma exhibits a high degree of similarity to those of a group of MarA-like activators that confer MDR in E . coli . A MalE-Rma fusion protein was purified to near homogeneity and was shown to interact with a DNA fragment carrying a MarA operator sequence . Furthermore, overexpression of rma in E . coli caused changes in the outer membrane protein profile that were similar to those reported for MarA . These results suggest that Rma might act as a transcriptional activator of the marA regulon.

Protein Sci, 2002 Feb, 11(2), 401 - 8
Crystal structure of the Yersinia pestis GTPase activator YopE; Evdokimov AG et al.; Yersinia pestis, the causative agent of bubonic plague, evades the immune response of the infected organism by using a type III (contact-dependent) secretion system to deliver effector proteins into the cytosol of mammalian cells, where they interfere with signaling pathways that regulate inflammation and cytoskeleton dynamics . The cytotoxic effector YopE functions as a potent GTPase-activating protein (GAP) for Rho family GTP-binding proteins, including RhoA, Rac1, and Cdc42 . Down-regulation of these molecular switches results in the loss of cell motility and inhibition of phagocytosis, enabling Y . pestis to thrive on the surface of macrophages . We have determined the crystal structure of the GAP domain of YopE (YopE(GAP); residues 90-219) at 2.2-A resolution . Apart from the fact that it is composed almost entirely of alpha-helices, YopE(GAP) shows no obvious structural similarity with eukaryotic RhoGAP domains . Moreover, unlike the catalytically equivalent arginine fingers of the eukaryotic GAPs, which are invariably contained within flexible loops, the critical arginine in YopE(GAP) (Arg144) is part of an alpha-helix . The structure of YopE(GAP) is strikingly similar to the GAP domains from Pseudomonas aeruginosa (ExoS(GAP)) and Salmonella enterica (SptP(GAP)), despite the fact that the three amino acid sequences are not highly conserved . A comparison of the YopE(GAP) structure with those of the Rac1-ExoS(GAP) and Rac1-SptP complexes indicates that few, if any, significant conformational changes occur in YopE(GAP) when it interacts with its G protein targets . The structure of YopE(GAP) may provide an avenue for the development of novel therapeutic agents to combat plague.

J Bacteriol, 2002 Feb, 184(3), 771 - 6
Effects of lipoprotein biogenesis mutations on flagellar assembly in Salmonella; Dailey FE et al.; Flagellar assembly requires the expression of a large number of flagellum-specific genes . However, mutations in a number of other genes in Salmonella and Escherichia coli have been shown to have pleiotropic effects that affect flagellar assembly . FlgH (the L-ring subunit of the flagellar basal body) is a lipoprotein whose modification is important for L-ring assembly . We therefore tested whether the lack of motility of Salmonella mutants defective in lipoprotein biogenesis is a result of inability to modify FlgH . Our results show that temperature-sensitive apolipoprotein N-acyltransferase {lnt(Ts)} mutants are nonflagellate at 42 degrees C . However, the flagellar assembly defect occurs at a much earlier step in the pathway than L-ring assembly . These mutants failed to assemble even an MS ring, presumably because of the observed decrease in transcription of fliF . In contrast, temperature-sensitive diacylglycerol transferase {lgt(Ts)} mutants were motile at 42 degrees C, provided the strains carried an lpp (Braun lipoprotein) mutation to permit growth . We have isolated second-site mutants from an lgt(Ts) lpp(+) strain that grow but are nonflagellate at 42 degrees C . Thus, lipoprotein biogenesis is a factor that is important for flagellar assembly.

J Bacteriol, 2002 Feb, 184(3), 706 - 17
Identification of the periplasmic cobalamin-binding protein BtuF of Escherichia coli; Cadieux N et al.; Cells of Escherichia coli take up vitamin B(12) (cyano-cobalamin {CN-Cbl}) and iron chelates by use of sequential active transport processes . Transport of CN-Cbl across the outer membrane and its accumulation in the periplasm is mediated by the TonB-dependent transporter BtuB . Transport across the cytoplasmic membrane (CM) requires the BtuC and BtuD proteins, which are most related in sequence to the transmembrane and ATP-binding cassette proteins of periplasmic permeases for iron-siderophore transport . Unlike the genetic organization of most periplasmic permeases, a candidate gene for a periplasmic Cbl-binding protein is not linked to the btuCED operon . The open reading frame termed yadT in the E . coli genomic sequence is related in sequence to the periplasmic binding proteins for iron-siderophore complexes and was previously implicated in CN-Cbl uptake in SALMONELLA: The E . coli yadT product, renamed BtuF, is shown here to participate in CN-Cbl uptake . BtuF protein, expressed with a C-terminal His(6) tag, was shown to be translocated to the periplasm concomitant with removal of a signal sequence . CN-Cbl-binding assays using radiolabeled substrate or isothermal titration calorimetry showed that purified BtuF binds CN-Cbl with a binding constant of around 15 nM . A null mutation in btuF, but not in the flanking genes pfs and yadS, strongly decreased CN-Cbl utilization and transport into the cytoplasm . The growth response to CN-Cbl of the btuF mutant was much stronger than the slight impairment previously described for btuC, btuD, or btuF mutants . Hence, null mutations in btuC and btuD were constructed and revealed that the btuC mutant had a strong impairment similar to that of the btuF mutant, whereas the btuD defect was less pronounced . All mutants with defective transport across the CM gave rise to frequent suppressor variants which were able to respond at lower levels of CN-Cbl but were still defective in transport across the CM . These results finally establish the identity of the periplasmic binding protein for Cbl uptake, which is one of few cases where the components of a periplasmic permease are genetically separated.

J Bacteriol, 2002 Feb, 184(3), 645 - 53
The ClpXP ATP-dependent protease regulates flagellum synthesis in Salmonella enterica serovar typhimurium; Tomoyasu T et al.; The ClpXP protease is a member of the ATP-dependent protease family and plays a dynamic role in the control of availability of regulatory proteins and the breakdown of abnormal and misfolded proteins . The proteolytic activity is rendered by the ClpP component, while the substrate specificity is determined by the ClpX component that has ATPase activity . We describe here a new role of the ClpXP protease in Salmonella enterica serovar Typhimurium in which ClpXP is involved in the regulation of flagellum synthesis . Cells deleted for ClpXP show "hyperflagellate phenotype," exhibit overproduction of the flagellar protein, and show a fourfold increase in the rate of transcription of the fliC encoding flagellar filament . The assay for promoter activity of the genes responsible for expression of the fliC showed that the depletion of ClpXP results in dramatic enhancement of the expression of the fliA encoding sigma factor final sigma(28), leaving the expression level of the flhD master operon lying at the top of the transcription hierarchy of flagellar regulon almost normal . These results suggest that the ClpXP may be responsible for repressing the expression of flagellar regulon through the control of the FlhD/FlhC master regulators at the posttranscriptional and/or posttranslational levels . Proteome analysis of proteins secreted from the mutant cells deficient for flhDC and clpXP genes demonstrated that the DeltaflhD mutation abolished the enhanced effect by DeltaclpXP mutation on the production of flagellar proteins, suggesting that the ClpXP possibly defines a regulatory pathway affecting the expression of flagellar regulon that is dependent on FlhD/FlhC master regulators.

Curr Biol, 2002 Jan 8, 12(1), R15 - 7
Microbial pathogenesis: new niches for salmonella; Brumell JH et al.; Salmonella occupies a vacuolar compartment inside cells of its host . Recent studies have shown that the fate of this vacuole is different in various cell types, and that the outcome of colonization is determined by both the infecting bacterium and defense mechanisms of the host cell.

J Environ Qual, 2001 Nov-Dec, 30(6), 2134 - 40
Viral and chemical tracer movement through contrasting soils; McLeod M et al.; Land treatment of animal or human waste can result in chemical and microbial contamination of shallow ground water and/or water-ways . We investigated the fate of a host-specific Salmonella bacteriophage and a nonreactive chemical (Br-) tracer when applied to large intact lysimeter soil cores (500 mm diam . by 700 mm high) . The soils included a poorly drained Gley Soil and well-drained Pumice, Allophanic, and Recent Soils . A depth of 30 mm of water containing the bacteriophage and Br- was applied to the soil at a rate of 5 mm h(-1) followed by up to about 1.8 pore volumes of simulated rainfall . Resulting leachates, collected continuously over at least one pore volume were analyzed for the bacteriophage and bromide (Br-) tracers . Bromide moved uniformly through the Pumice and Allophanic Soils with peak concentrations at about 1 pore volume, while the bacteriophage was detected only at trace levels or not at all . In contrast, both Br- and bacteriophage tracers moved rapidly through Gley and Recent Soils, appearing early in the leachate and then tailing off . Such flow patterns in the Gley and Recent Soils are indicative of bypass flow . Coarse soil structure in the Gley Soil, and finger-flow due to water repellency in the sandy Recent Soil are considered responsible for the observed bypass flow in these two soils . Allophanic and Pumice Soils have finer, more porous soil structure leading to a predominance of matrix flow over bypass flow . This study suggests vertical movement of viruses varies significantly with soil type.

Int J Food Microbiol, 2001 Dec 30, 71(2-3), 263 - 6
Salmonella serotypes isolated from chicken meat in Albania; Beli E et al.; A total of 31 salmonellae, belonging to four different serogroups and nine serotypes, were isolated from 30 out of 461 (6.5%) chicken meat samples, taken during a 3-year period, from 1996 to 1998 . There were no significant differences among years in Salmonella positive samples, ranging from 5.1% to 8% . The most frequently encountered serotype was Salmonella enteritidis, isolated in 16 out of 30 Salmonella positive samples (53.3%), but its predomination was clearly evident only in 1996 . The other isolated serotypes were S . senftenberg (three isolates), S . newport (two isolates), and S . abony, S . agona, S . banana, S . brancaster, S . infantis and S . oslo with only one isolate each . Four other Salmonella strains were not fully serotyped.

Avian Dis, 2001 Oct-Dec, 45(4), 875 - 86
Determination of close genetic relatedness of the major Salmonella enteritidis phage types by pulsed-field gel electrophoresis and DNA sequence analysis of several Salmonella virulence genes; Hudson CR et al.; Salmonella enteritidis (SE) is an important cause of egg-associated outbreaks in both Europe and the United States . Phage typing has become an important epidemiologic tool in identifying the source of outbreaks . Limitations of phage typing have become apparent with wholesale egg distributors that have multiple suppliers in an area where a particular phage type is endemic . Several different molecular typing methods were evaluated for their discriminatory power to identify genetic differences among different SE phage types isolated in Europe and the United States . Pulsed-field gel electrophoresis (PFGE) identified a single DNA pattern among the different SE phage types . Comparison of the nucleotide sequence for several Salmonella virulence genes failed to identify a single nucleotide change in the gene sequences from most SE isolates, regardless of phage type . On the basis of these results, the different SE phage types appear to be genetically related or clonal . However, with primers 1283 and Opa4, it was possible to differentiate not only SE isolates from different geographic locations but those within a specific geographic locale as well by random amplified polymorphic DNA polymerase chain reaction . Any chance for discerning genetic differences among isolates will need to rely on molecular techniques other than PFGE.

Avian Dis, 2001 Oct-Dec, 45(4), 797 - 806
Induction of humoral immune response and protective immunity in chickens against Salmonella enteritidis after a single dose of killed bacterium-loaded microspheres; Liu W et al.; Formalin-inactivated Salmonella enteritidis phage type 4 strain 119/95 (SE) was encapsulated in biodegradable poly (DL-lactide co-glycolic acid) PLGA; (65:35) microspheres by a modified water-in-oil-in-water (w/o/w) double-emulsion solvent extraction/evaporation technique . These SE-loaded microspheres (SE-MS) were porous and spherical in shape with diameters of 0.4-10 microm and 20-80 microm in two preparations . SE-MS were subsequently used to vaccinate specific-pathogen-free chickens in a single dose in order to investigate the potency of a single-dose vaccination in inducing immune responses and protective immunity . In Experiment 1, 4-wk-old chickens that were vaccinated intramuscularly with 20-80-microm SE-MS generated long lasting (over 6 mo) and persistently high serum anti-SE immunoglobulin (Ig)G antibody response . In Experiment 2, 2-wk-old chickens were vaccinated orally with 0.4-10-microm or intramuscularly with 20-80-microm SE-MS and challenged with 10(9) colony-forming units of homologous SE strain at 6 wk postvaccination . When challenged intramuscularly, one each of the orally vaccinated (n = 10) and the intramuscularly vaccinated birds (n = 10) showed clinical signs and death, whereas all of the nonvaccinated control birds (n = 12) were sick and 11 of them were killed . When challenge was via oral route, 26.1% of cloacal swabs and 24.0% of organs (liver, spleen, and cecum) collected from orally vaccinated birds (n = 35) were positive for SE, comparable to 27.9% of feces and 18.7% of organs from the intramuscularly vaccinated birds (n = 35) . These figures were significantly lower than those for nonvaccinated birds (n = 30) from which 59.3% of feces and 44.0% of organs tested SE positive (P < 0.05) . The humoral immune response was also determined after vaccination with a single dose . The intramuscular vaccination elicited higher serum IgG response than oral administration, but the latter elicited a significant intestinal mucosal IgA antibody response . This is the first evidence that chickens vaccinated with killed SE-loaded PLGA microspheres, intramuscularly and orally in a single dose, developed systematic and local immune responses, thereby conferring protective immunity.

Avian Dis, 2001 Oct-Dec, 45(4), 1044 - 9
Dynamics of Salmonella contamination in a commercial quail operation; Sander J et al.; Control of carcass contamination requires knowledge of the source and dynamics of spread of Salmonella in commercial poultry production . We examined Salmonella contamination at a U.S . commercial quail operation . Pulsed-field gel electrophoresis (PFGE) was used to type isolates in order to trace Salmonella throughout this production environment . During a 6-mo survey, Salmonella serotypes hadar, typhimurium, typhimurium variant Copenhagen, and paratyphi were encountered within this poultry operation . Ninety-four percent of the Salmonella isolated from breeder and production houses and from carcass rinses belonged to Salmonella serotypes typhimurium variant Copenhagen and hadar . There were six distinct S . typhimurium variant Copenhagen genetic types, as identified by PFGE, present within this particular poultry operation . Seventy-nine percent of S . typhimurium variant Copenhagen identified from the environment of the breeder and production houses produced the same PFGE pattern . Thirty-eight percent of S . typhimurium Copenhagen isolated from carcass rinses and the breeder house shared the same PFGE DNA pattern . This study demonstrates the transmission of salmonellae throughout this production environment, from the breeders to their progeny and to the birds ultimately processed for human consumption.

Microbiology, 2002 Jan, 148(Pt 1), 113 - 22
The starvation-stress response of Salmonella enterica serovar Typhimurium requires sigma(E)-, but not CpxR-regulated extracytoplasmic functions; Kenyon WJ et al.; Starvation of Salmonella enterica serovar Typhimurium (S . Typhimurium) for an exogenous source of carbon and energy (C-starvation) induces the starvation-stress response (SSR) . The SSR functions to (i) maintain viability during long-term C-starvation and (ii) generate cross-resistance to other environmental stresses . The SSR is, at least partially, under the control of the alternative sigma factor, sigma(S) . It is hypothesized that C-starvation causes cell envelope stresses that could induce the sigma(E) and/or Cpx regulons, both of which control extracytoplasmic functions and, thus, may play a role in the regulation of the SSR . In support of this hypothesis, Western blot analysis showed that the relative levels of sigma(E) increased during C-starvation, peaking after approximately 72 h of C-starvation; in contrast, CpxR levels remained relatively constant from exponential phase up to 72 h of C-starvation . To determine if sigma(E), and thus the regulon it controls, is an essential component of the SSR, several mutant strains were compared for their abilities to survive long-term C-starvation and to develop C-starvation-induced (CSI) cross-resistances . An rpoE mutant strain was significantly impaired in both long-term C-starvation survival (LT-CSS) and in CSI cross-resistance to challenges with 20 mM H(2)O(2) for 40 min, 55 degrees C for 16 min, pH 3.1 for 60 min and 870.2 USP U polymyxin B ml(-1) (PmB) for 60 min, to varying degrees . These results suggest that C-starvation can generate signals that induce the rpoE regulon and that one or more members of the sigma(E) regulon are required for maximal SSR function . Furthermore, evidence suggests that the sigma(E) and sigma(S) regulons function through separate mechanisms in the SSR . In contrast, C-starvation does not appear to generate signals required for Cpx regulon induction which support the findings that it is not required for LT-CSS or cross-resistance to H(2)O(2), pH 3.1 or PmB challenges . However, it was required to achieve maximal cross-resistance to 55 degrees C . Therefore, sigma(E) is a key regulatory component of the SSR and represents an additional sigma factor required for the SSR of SALMONELLA:

Microb Pathog, 2002 Jan, 32(1), 15 - 25
Excess production of interleukin-12 subunit p40 stimulated by the virulence plasmid of Salmonella enterica serovar Typhimurium in the early phase of infection in the mouse; Chang CC et al.; The production of interleukin-12 (IL-12) and its subunits in response to Salmonella enterica serovar Typhimurium infection in the BALB/c mouse was examined . Unlike wild-type Typhimurium, a plasmidless strain, isolated by curing of the virulence plasmid (pSTV), did not stimulate excess IL-12p40 production . When a Tn 5 tagged pSTV was transferred back to the plasmidless strain, the ability to stimulate IL-12p40 production was restored . However, a strain harbouring another Tn50pSTV failed to stimulate excess IL-12p40 production . This Tn 5 insertion area, located on fragment H3 of pSTV, was designated spf (stimulation of protein forty) . The ability to stimulate IL-12p40 production was restored in a partial diploid that carried a wild-type fragment covering the spf site . There is one known gene, repA, a locus, rsk, and two putative ORFs, in the vicinity of the Tn 5 insertion site; however, these are not spf . The precise location of the spf locus is still unknown .

Genetics, 2001 Dec, 159(4), 1405 - 14
Growth-dependent DNA breakage and cell death in a gyrase mutant of Salmonella; Gari E et al.; A class of gyrase mutants of Salmonella enterica mimics the properties of bacteria exposed to quinolones . These mutants suffer spontaneous DNA breakage during normal growth and depend on recombinational repair for viability . Unlike quinolone-treated bacteria, however, they do not show accumulation of cleavable gyrase-DNA complexes . In recA or recB mutant backgrounds, the temperature-sensitive (ts) allele gyrA208 causes rapid cell death at 43 degrees . Here, we isolated "suppressor-of-death" mutations, that is, secondary changes that allow a gyrA208 recB double mutant to survive a prolonged exposure to 43 degrees and subsequently to form colonies at 28 degrees . In most isolates, the secondary change was itself a ts mutation . Three ts alleles were mapped in genes coding for amino acyl tRNA synthetases (alaS, glnS, and lysS) . Allele alaS216 completely abolished DNA breakage in a gyrA208 recA double mutant . Likewise, treating this mutant with chloramphenicol prevented death and DNA damage at 43 degrees . Additional suppressors of gyrA208 lethality include rpoB mutations and, surprisingly, icd mutations inactivating isocitrate dehydrogenase . We postulate that the primary effect of the gyrase alteration is to hamper replication fork movement . Inhibiting DNA replication under conditions of continuing macromolecular synthesis ("unbalanced growth") activates a mechanism that causes DNA breakage and cell death, reminiscent of "thymineless" lethality.

Clin Transplant, 2001, 15 Suppl 4, 11 - 22
Gastrointestinal infectious disease complications following transplantation and their differentiation from immunosuppressant-induced gastrointestinal toxicities; Rubin RH; It is often very difficult to distinguish between infection-related and immunosuppression-related gastrointestinal (GI) complications after transplantation . The risk of infection itself is determined by the patient's net state of immunosuppression as well as the presence of anatomic or technical abnormalities and the patient's epidemiological exposures . Of the anatomic abnormalities, diverticulitis is a particular problem in transplant patients, with a high rate of perforation and abscess formation . The causes of infectious disease syndromes are very different immediately after, early after, and late after transplantation . Infection during the first month may result from a pre-existing infection in the donor or recipient, or from the surgical wound, endotracheal tube, vascular access or drainage . During 1-6 months after transplantation, viruses attack and, with sustained immunosuppression, make opportunistic infections possible . Beyond 6 months after transplantation, the 80% of patients with good result from the transplant are at risk primarily for community-acquired microbes, including such enteric pathogens as Salmonella . Of the remaining patients, 10% have chronic viral infections and the 10% who have poor allograft function are at greatest risk for opportunistic infection . This time line is helpful in determining whether a GI complication is likely to be related to infection rather than a specific effect of an immunosuppressant drug . Fever, inflammatory cells in the stool, abnormalities on endoscopy or computed tomography and leukocytosis can be useful in the diagnosis but are inconsistent markers for an infectious cause.

Clin Diagn Lab Immunol, 2002 Jan, 9(1), 115 - 25
Effect of protein SV-IV on experimental Salmonella enterica serovar Typhimurium infection in mice; Romano-Carratelli C et al.; Seminal vesicle protein IV (SV-IV) is a secretory anti-inflammatory, procoagulant, and immunomodulatory protein produced in large amounts by the seminal vesicle epithelium of the rat under the strict transcriptional control of androgen . In particular, this protein was shown to possess the ability to markedly inhibit in vivo the humoral and cell-mediated immune responses of mice to nonbacterial cellular antigens (sheep erythrocytes and spermatozoa) . We report data that demonstrate that in mice treated with SV-IV and infected with Salmonella enterica serovar Typhimurium, SV-IV is able to downregulate some important immunological and biochemical parameters that serovar Typhimurium normally upregulates in these animals . This event did not correlate with a lower bacterial burden but was associated with a markedly increased one (300%) . Furthermore, the treatment of mice with SV-IV alone also produced a significant increase in the rate of mortality among serovar Typhimurium-infected animals . The mechanism underlying these phenomena was investigated, and the strong immunosuppression produced by SV-IV in serovar Typhimurium-infected mice was suggested to be the basis for the increased rate of mortality . The SV-IV-mediated immunosuppression was characterized by a decrease in the humoral and cell-mediated immune responses, altered lymphocyte-macrophage interaction, downregulation of cytokine and inducible nitric oxide synthase gene expression, inhibition of macrophage phagocytosis and intracellular killing activities, and absence of apoptosis in the splenocyte population of SV-IV- and serovar Typhimurium-treated mice . The immunosuppressive activity of SV-IV was specific and was not due to aspecific cytotoxic effects . SV-IV-specific receptors (K(d) = 10(-8) M) occurring on the macrophage and lymphocyte plasma membranes may be involved in the molecular mechanism underlying the SV-IV-mediated immunosuppression . Some results obtained by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay also revealed a functional impairment of mitochondria (a decrease in mitochondrial dehydrogenase activity), thus indicating the possible implication of these organelles in the immunosuppressive process.

J Egypt Soc Parasitol, 2001 Dec, 31(3), 767 - 80
Effect of midgut bacteria of Culex pipiens L . on digestion and reproduction; Fouda MA et al.; An investigation was carried out to evaluate the influence of symbiotic bacteria associated with Culex pipiens L . on pre-oviposition and blood meal digestion periods, and reproductive potential (fecundity and fertility) . Aposymbiotic females were obtained by feeding the normal females on 10% sucrose solution mixed with antibiotic (Tarivid) for three days before feeding them on normal blood meals from a pigeon host . A total of 4 genera were previously isolated from the midgut of C . pipiens . These genera were: Bacillus, Streptococcus, Staphylococcus, and Salmonella and Shigella . It seems that the period of blood meal digestion preceded the pre-oviposition period of both bacterial free females and bacterial-free females treated with one of the aforementioned bacteria . In addition, it is obviously clear that, the presence of the two bacterial genera: Bacillus and Staphylococcus in the midgut of C . pipiens is essential for normal and high fecundity . Generally, it is evident that the symbionts (gut bacteria) are essential for the completion of embryonic development.

J Clin Microbiol, 2002 Jan, 40(1), 52 - 60
Modeling of 5' nuclease real-time responses for optimization of a high-throughput enrichment PCR procedure for Salmonella enterica; Knutsson R et al.; The performance of a 5' nuclease real-time PCR assay was studied to optimize an automated method of detection of preenriched Salmonella enterica cells in buffered peptone water (BPW) . The concentrations and interactions of the PCR reagents were evaluated on the basis of two detection responses, the threshold cycle (C(T)) and the fluorescence intensity by a normalized reporter value (DeltaR(n)) . The C(T) response was identified as the most suitable for detection modeling to describe the PCR performances of different samples . DNA extracted from S . enterica serovar Enteritidis was studied in double-distilled H2O (ddH2O) and in two different enrichment media (brain heart infusion and BPW) with two PCR mixtures based on AmpliTaq Gold or rTTH: A descriptive model was proposed and fitted to the available experimental data . Equivalent PCR performances for the two PCR mixtures were obtained when DNA was diluted in ddH2O . However, the level of detection of DNA was affected when BPW was present during amplification . Use of the rTth mixture generated a 1-log-unit wider linear range of amplification, and the DNA detection levels were 2 x 10(-13) g/microwell for the rTth mixture and 2 x 10(-12) g/microwell for the AmpliTaq Gold mixture . To verify the improved amplification capacity of the rTth mixture, BPW was inoculated with 1 CFU of S . enterica serovar Enteritidis per ml and the mixture was incubated at 30 degrees C . Samples for PCR were withdrawn every 4 h during a 36-h enrichment . Use of the rTth mixture resulted in an earlier PCR detection during enrichment than use of the AmpliTaq Gold mixture . For accurate detection (C(T) < or = 30) of S . enterica serovar Enteritidis inoculated in BPW, the rTth mixture required 8.4 h of enrichment, while the AmpliTaq Gold mixture needed 11.6 h . In conclusion, the principle applied can improve the methodology of 5' nuclease real-time PCR for numerical optimization of sample pretreatment strategies to provide automated diagnostic PCR procedures.

Appl Environ Microbiol, 2002 Jan, 68(1), 181 - 6
Salmonella enterica serotype Bredeney: antimicrobial susceptibility and molecular diversity of isolates from Ireland and Northern Ireland; Cormican M et al.; Salmonella enterica serotype Bredeney has emerged as the third most commonly identified serotype among human clinical isolates referred to the Irish National Salmonella Reference Laboratory in the years 1998 to 2000 . A collection of 112 isolates of S . enterica serotype Bredeney collected during the period 1995 to 1999 from animal, food, and human sources from both Ireland and Northern Ireland were studied . Antimicrobial susceptibility testing, pulsed-field gel electrophoresis (PFGE), and DNA amplification fingerprinting (DAF) were performed on all isolates . Plasmid profiles were examined on a subset of 33 isolates . A high proportion (74%) of isolates were susceptible to all antimicrobial agents tested . Resistance to both sulfonamide and trimethoprim was observed in 21% of isolates, and resistance to multiple (five) antimicrobial agents was observed in a single isolate (0.9%) . Eight different PFGE patterns were obtained, with 87% of isolates grouping as PFGE type A . PFGE type A was predominant in animals, food, and humans . There was good overall concordance between the groups identified by PFGE and DAF . Overall results indicate that most S . enterica serotype Bredeney isolates in Ireland and Northern Ireland from animal and human sources are clonally related.

Appl Environ Microbiol, 2002 Jan, 68(1), 86 - 92
Inoculation onto solid surfaces protects Salmonella spp . during acid challenge: a model study using polyethersulfone membranes; Gawande PV et al.; Salmonellae are the most frequently reported cause of outbreaks of food-borne gastroenteritis in the United States . In clinical trials, the oral infective dose (ID) for healthy volunteers was estimated to be approximately 1 million cells . However, in reports from various outbreaks, the ID of Salmonella species associated with solid foods was estimated to be as few as 100 cells . We found that fresh-cut produce surfaces not only provided suitable solid support for pathogen attachment but also played a critical role in increasing the acid tolerance of the pathogen . However the acidic nature of certain produce played no role in making salmonellae resistant to stomach acidity . Inoculation onto fresh-cut produce surfaces, as well as onto inert surfaces, such as polyethersulfone membranes and tissue paper, increased the survival of salmonellae during acid challenge (50 mM Na-citrate, pH 3.0; 37 degrees C; 2 h) by 4 to 5 log units . Acid challenge experiments using cells inoculated onto polyethersulfone membranes provided a model system suitable for studying the underlying fundamentals of the protection that occurs when Salmonella strains are associated with solid foods . The surface-associated acid protection, which was observed in several Salmonella strains, required de novo protein synthesis and was independent of stationary-phase sigma transcription factor.

Exp Gerontol, 2002 Jan-Mar, 37(2-3), 235 - 47
Overproduction of monokines by leukocytes after stimulation with lipopolysaccharide in the elderly; Gabriel P et al.; The elderly suffer from an impaired immune function being obvious in a higher susceptibility to infections . Especially the rate of complications after infection with Salmonella, normally confined to the gastrointestinal tract, is raised . We compared in a whole blood assay and in vitro stimulation of peripheral blood mononuclear cell (PBMC) the secretion of interleukin (IL)-1-beta, IL-6, IL-8 and TNF-alpha, after stimulation with lipopolysaccharid (LPS) from Salmonella abortus equi and Escherichia coli, phytohaemagglutinin (PHA) and toxic shock syndrome toxin-1 (TSST-1) by leukocytes of healthy young donors, healthy elderly and healthy elderly fulfilling the SENIEUR protcol . Significantly higher secretion of IL-1-beta, IL-6 and IL-8 after stimulation with LPS were found in the SENIEUR elderly compared to young donors . IL-1-beta, IL-6 and IL-8 were elevated in the whole blood samples of the healthy elderly controls as well . After stimulation of whole blood samples from these healthy elderly with LPS, IL-1 and IL-6 secretion was significantly elevated, but stimulation of their PBMCs showed lower amounts of produced cytokines compared to the PBMCs of healthy young donors . The results suggest that the elvated cytokine releases are caused by an interaction of LPS with a serum factor in the blood of the elderly . Such an overproduction of these inflammatory cytokines by moncytes and neutrophils may be in part responsible for many symptoms elderly people suffer from during an infection with Salmonella.

Biofizika, 2001 Nov-Dec, 46(6), 1081 - 5
{Effect of R plasmid on cell membrane structure in Salmonella derby}; Pepoian AZ et al.; The structure of membranes of Salmonella derby cells both containing R-plasmid and free of plasmid was studied by small- and large-angle X-ray diffraction . Reflections with interplane distances of 8 and 11 A were detected, which are typical of plasmid-carrying S . derby cells . These reflections are assumed to be due to equidistant well ordered positions of the polar groups of phosphatidylcholine and phosphatidylethanolamine molecules on membrane surface . It is also suggested that the formation of these structures is determined by peculiar hydrophilic-hydrophobic interactions of the phospholipid in membranes.

J Food Prot, 2001 Dec, 64(12), 2083 - 7
Thermal lethality of Salmonella Senftenberg and Listeria innocua in fully cooked and packaged chicken breast strips via steam pasteurization; Murphy RY et al.; Fully cooked chicken breast strips were surface inoculated to contain 9 log10 (CFU/g) Salmonella Senftenberg or Listeria innocua . The inoculated products were vacuum packaged in 0.2-mm-thick barrier bags (241 by 114 mm), then steam pasteurized at 88 degrees C in a continuous process for 26 to 40 min or in a batch process for 33 to 41 min . After the treatments, the products were analyzed for the survivors of Salmonella or Listeria . The models were developed to correlate the surviving rate of Salmonella and Listeria with cooking time for both continuous and batch processes . A cooking time of 34 min was needed to achieve 7 logs of the reduction in a batch process . To achieve the same log reduction, a longer (6 min) cooking time was needed in a batch process than in a continuous process . The results from this study will be useful for processors to evaluate postcooking treatment procedures for ready-to-eat meat products.

J Food Prot, 2001 Dec, 64(12), 2067 - 70
Evaluation of subtherapeutic use of the antibiotics apramycin and carbadox on the prevalence of antimicrobial-resistant Salmonella infection in swine; Edrington TS et al.; The antibiotics apramycin and carbadox were fed to growing swine, and the prevalence of Salmonella isolates that are resistant to apramycin and related aminoglycoside antibiotics was examined . Three hundred twelve Salmonella-positive pigs raised on one of five farms in an integrated swine operation and slaughtered at a central plant were used . All farms fed carbadox during the grower phase, and two farms administered apramycin during the first 21 days of age . Ileocolic lymph nodes and cecal contents were sampled at slaughter . One hundred of the 312 pigs were randomly selected to examine apramycin- and carbadox-resistant Salmonella infection, while all 312 pigs were used to evaluate the association between apramycin exposure and infection with Salmonella organisms resistant to amikacin, gentamicin, kanamycin, and streptomycin . Antimicrobial resistance was determined using disk diffusion and breakpoint concentrations . Apramycin treatment appeared to have little effect on apramycin- (12.5 versus 20.9%) or streptomycin- (76.4 versus 73.5%) resistant Salmonella isolates when averaged across farms and compared to control animals . Feeding carbadox resulted in carbadox-resistant Salmonella infection in only 5.3% of the isolates on one farm . The prevalence of amikacin-, gentamicin-, and kanamycin-resistant Salmonella isolates on farms feeding apramycin and carbadox were 0, 0, and 1.8%, respectively . Serogroup B was the most prevalent serogroup isolated, followed by C1 and E1 . Apramycin and carbadox treatment did not appear to have any effect on the serogroup isolated . Subtherapeutic use of carbadox and apramycin did not appear to increase the prevalence of antimicrobial-resistant Salmonella in market-age swine.

J Food Prot, 2001 Dec, 64(12), 2053 - 7
Fate of salmonellae in calcium-supplemented orange juice at refrigeration temperature; Sharma M et al.; Recent outbreaks of salmonellosis associated with orange juice have raised interest concerning the survival and growth of Salmonella in juice supplemented with calcium . A study was done to determine the influence of various calcium supplements on the survival of salmonellae in orange juice held at 4 degrees C for up to 32 days . Isolates of Salmonellal Muenchen (inoculum 1), Salmonella isolates from humans and animals (inoculum 2), and Salmonella isolates from produce outbreaks (inoculum 3) were inoculated into pasteurized orange juices with pH values ranging from 3.96 to 4.19 and containing 350 mg of calcium per 240-ml serving (1.46 mg of calcium/ml) . Populations of Salmonella declined rapidly in juice containing calcium lactate (CaL), with counts decreasing from 4.86 log10 CFU/ml to < 1 log10 CFU/ml within 16 days, regardless of the Salmonella serotypes present in inoculum . Counts decreased from 4.89 log10 CFU/ml to < 1 log10 CFU/ml in orange juice supplemented with CaL and tricalcium phosphate (TCP) within 30 days . These reductions were significantly (P < or = 0.05) higher than those of the control (no calcium added), in which Salmonella populations decreased 3.19 +/- 0.20 log10 CFU/ml over 32 days . Populations in orange juice containing TCP or calcium citrate (CC) declined 1.34 +/- 0.20 log10 CFU/ml and 1.96 +/- 0.20 log10 CFU/ml, respectively, over 32 days . These counts were significantly higher than respective control counts in juice stored for 32 days . Populations of Salmonella of inoculum 3 inoculated into juice containing calcium citrate malate (CCM) were significantly higher than in the control . Higher numbers of cells in inoculum 3 also survived compared to numbers of cells of inocula 1 or 2 in juice supplemented with CCM . This study reveals that the form of calcium used to supplement orange juice influences the ability of salmonellae to survive.

J Food Prot, 2001 Dec, 64(12), 1917 - 21
Comparison of Salmonella Enteritidis infection in hens molted via long-term feed withdrawal versus full-fed wheat middling; Seo KH et al.; Molting is an important economic management tool for the layer industry as a means of maximizing the effective laying life of a flock . Previous work has shown that molting birds through feed removal (FM) increased the severity of a Salmonella Enteritidis (SE) infection . The current study was conducted to follow the progression of an SE infection in unmolted hens versus hens molted via 14-day FM or ad libitum feeding of wheat middlings (WM), in the presence or absence of 2.5% lactose administered in the drinking water . In two trials of the experiment, all hens were infected with approximately 1 x 10(7) SE at day 4 of molt and sampled for SE shedding on days 4, 10, 17, and 24 postinfection (PI) . Organ levels of SE were determined on day 7 PI . All molt procedures caused cessation of egg lay within 3 to 7 days . In trials 1 and 2, birds subjected to total FM shed 3 to 5 logs more SE than either the control birds (unmolted) or the birds fed WM on days 4 and 10 PI . Liver and spleen, ovary, and cecum counts were also significantly (P < 0.05) higher in the fasted birds in one trial and liver and spleen and cecum counts in the second . No differences in any of the SE counts were observed in unmolted versus WM-fed birds . Lactose supplementation in drinking water did not provide any advantage in reducing SE infection in either trial . These results indicate that there are alternative methods to long-term FM that can be used to molt birds and not increase the risk for SE problems . How these alternative methods compare with FM with regard to second-cycle egg production and the mechanisms involved in the reduced SE shedding remain to be investigated.

J Food Prot, 2001 Dec, 64(12), 1912 - 6
Monitoring of chicken houses and an attached egg-processing facility in a laying farm for Salmonella contamination between 1994 and 1998; Murase T et al.; Two chicken houses and an attached egg-processing facility in a laying farm were sampled between 1994 and 1998 to investigate Salmonella contamination . Each of the houses was environmentally controlled and fitted with egg belts that transported eggs from the houses to the egg-processing facility . Four hundred twenty-eight Salmonella isolates were obtained from 904 environmental samples collected from the houses . Two hundred fifty-two of the 428 (58.9%) isolates yielded five serotypes as follows: Salmonella enterica subsp . enterica serovar Livingstone, Salmonella serovar Cerro, Salmonella serovar Montevideo, Salmonella serovar Mbandaka, and Salmonella serovar Corvallis . The remaining (41.1%, 176 of 428) isolates included four other serotypes and isolates that were untypeable . Salmonella isolates obtained from the drain water collected after the washing of the eggs in the egg-processing facility yielded the same serotypes as those found in the chicken houses . Strains having an identical pulsed-field gel electrophoresis (PFGE) pattern were continually recovered from a house for more than 1 year . Several strains of Salmonella Cerro, Salmonella Mbandaka, and Salmonella Montevideo obtained from both the houses and from the egg-processing facility were indistinguishable by PFGE, respectively . These results suggest that Salmonella organisms originating from a single clone colonized the chicken houses and that the egg belts are likely to be one of the means by which Salmonella organisms are spread from one house to the others.

J Food Prot, 2001 Dec, 64(12), 1891 - 8
Use of green fluorescent protein expressing Salmonella Stanley to investigate survival, spatial location, and control on alfalfa sprouts; Gandhi M et al.; Laser scanning confocal microscopy (LSCM) was used to observe the interaction of Salmonella Stanley with alfalfa sprouts . The green fluorescent protein (gfp) gene was integrated into the chromosome of Salmonella Stanley for constitutive expression, thereby eliminating problems of plasmid stability and loss of signal . Alfalfa seeds were inoculated by immersion in a suspension of Salmonella Stanley (ca . 10(7) CFU/ml) for 5 min at 22 degrees C . Epifluorescence microscopy demonstrated the presence of target bacteria on the surface of sprouts . LSCM demonstrated bacteria present at a depth of 12 microm within intact sprout tissue . An initial population of ca . 10(4) CFU/g seed increased to 7.0 log CFU/g during a 24-h germination period and then decreased to 4.9 log CFU/g during a 144-h sprouting period . Populations of Salmonella Stanley on alfalfa seeds decreased from 5.2 to 4.1 log CFU/g and from 5.2 to 2.8 log CFU/g for seeds stored 60 days at 5 and 22 degrees C, respectively . The efficacy of 100, 200, 500, or 2,000 ppm chlorine in killing Salmonella Stanley associated with sprouts was determined . Treatment of sprouts in 2,000 ppm chlorine for 2 or 5 min caused a significant reduction in populations of Salmonella Stanley . Influence of storage on Salmonella Stanley populations was investigated by storing sprouts 4 days at 4 degrees C . The initial population (7.76 log CFU/g) of Salmonella Stanley on mature sprouts decreased (7.67 log CFU/g) only slightly . Cross-contamination during harvest was investigated by harvesting contaminated sprouts, then directly harvesting noncontaminated sprouts . This process resulted in the transfer of ca . 10(5) CFU/g Salmonella Stanley to the noncontaminated sprouts.

Orv Hetil, 2001 Nov 18, 142(46), 2557 - 61
{Disorders of interferon-gamma activation pathways: new group of primary immune deficiency diseases}; Erdos M et al.; Protective immunity to intracellular bacteria such as mycobacteria and salmonella depends on intact cell-mediated immunity . Major effector mechanisms of cell-mediated immunity involve activation of macrophages by T helper-1 cytokines, particularly interferon-gamma . Patients with genetic deficiency of T helper-1 cytokines (IFN-gamma, IL-12) or T helper-1 cytokine receptors (IFN-gamma receptor, IL-12 receptor) are susceptible to infections with poorly pathogenic mycobacteria, and salmonella, suggesting that T helper-1 cytokines are essential in host defense against these pathogens . This review reports on the genetic and clinical characteristics of primary deficiencies of interferon-gamma activation pathways.

J Vet Med Sci, 2001 Nov, 63(11), 1221 - 4
Effects of rearing conditions on the colonization of Salmonella enteritidis in the cecum of chicks; Asakura H et al.; Salmonella enteritidis is the cause of human salmonellosis associated with contaminated eggs . In this study, we artificially challenged S . enteritidis to chicks just after hatching, and the effects of breeding conditions on the intestinal carriage of S . enteritidis were examined . S . enteritidis was not directly detected from spleen, liver and blood, but were constantly isolated from the cecal contents throughout the experiment . When chicks were reared in the unsanitary conditions and in the high housing density, the numbers of S . enteritidis increased . The subsequent experiment was undertaken to examine whether the antibacterial additive in a feed would have any impact on S . enteritidis colonization in chicks . Some antibiotic effective on the growth promotion had an influence on S . enteritidis colonization.

Res Microbiol, 2001 Dec, 152(10), 907 - 9
Supplement 2000 (no . 44) to the Kauffmann-White scheme; Popoff MY et al.; This supplement reports the characterization of 12 new Salmonella serovars recognized in 2000 by the WHO Collaborating Centre for Reference and Research on Salmonella: nine were assigned to S . enterica subsp . enterica, two to subspecies salamae, and one to subspecies diarizonae.

Water Res, 2002 Jan, 36(1), 25 - 32
Genotoxic response of Austrian groundwater samples treated under standardized UV (254 nm)--disinfection conditions in a combination of three different bioassays; Haider T et al.; Ground water samples from different geographic areas in Austria, with different amounts of natural and anthropogenic organic compounds were treated with a standardized low pressure UV (254 nm)-irradiation laboratory flow-through system (UV fluence: 800 J/m2) . The genotoxic activities of the water samples before and after the UV disinfection were investigated using a combination of three different bioassays which complement each other with regard to their sensitivity detecting different genotoxins . The test battery comprises the Salmonella/microsome assay (Ames test with TA98 . TA 100 and TA 102, with and without S9 mix) and two micronucleus tests with the plant Tradescantia (clone #4430) and with primary rat hepatocytes . Overall, the tested Austrian groundwater samples used for human consumption caused only weak genotoxic activities compared to drinking water samples reported from other countries under similar experimental conditions . With the exception of one weak positive result in the Ames test (only in strain TA98 without S9 mix) with an induction factor of 1.9) all samples after UV disinfection were devoid of additional mutagenic and clastogenic activities compared to the samples before UV disinfection.

Water Environ Res, 2001 Sep-Oct, 73(5), 607 - 11
Persistency of bacterial indicators in biosolids stabilization with coal fly ash and lime; Wong JW et al.; Alkaline coal fly ash and lime were tested for their effectiveness in pathogen removal from biosolids at different time intervals and temperatures . Coal fly ash at 10 and 35% w/w was mixed with dewatered biosolids and then the ash-biosolids mixture was mixed separately with 0, 1.1, 2.2, 4.4, 8.5, 11, and 18% calcium oxide (w/w on a dry weight basis) with and without heating to 55 degrees C . Total bacteria, salmonella, and total coliforms were monitored at various time intervals . Both ash-biosolids mixtures with or without lime amendment had a significantly lower total bacterial population than the biosolids control, but the residual indigenous bacterial flora in the ash and lime stabilized biosolids still maintained a population of greater than 10(4) g(-1) dry biosolids . Alkaline-stabilized biosolids with a lime amendment rate greater than 8.5% could maintain pH greater than or equal to 12 for more than 2 hours, which effectively removed total coliforms and salmonella in the mixture . Heat treatment to 55 degrees C and a storage time of 14 days provided an added advantage resulting in a further reduction in pathogens for all treatments . It is recommended that 10% ash-biosolids mixture should be amended with a minimum of 8.5% lime on a dry weight basis for at least 2 hours to achieve acceptable levels of salmonella and total coliforms to ensure no pathogenic risk following land application.

J Environ Health, 2001 Dec, 64(5), 9 - 12, 33; quiz 37-8
An outbreak of Norwalk-like viral gastroenteritis in a frequently penalized food service operation: a case for mandatory training of food handlers in safety and hygiene; Kassa H; In 1999, in Toledo, Ohio, an outbreak of gastroenteritis occurred among people who had attended a Christmas dinner banquet and had eaten food prepared by a local caterer . Overall, 93 of the 137 attendees (67.9 percent) reported illness . Eight sought medical care, and one was hospitalized . Case-control studies revealed that the illness was associated with eating tossed salad (odds ratio {OR} = 2.5, 95 percent confidence interval {CI} = 1.02-6.26) . Eleven of 12 stool specimens that were taken from ill people tested positive for a Norwalk-like virus (NLV) but were negative for E . coli O157:H7, Salmonella, and Shigella . The primary source of the outbreak was not determined, but an infected food handler may have played a role in the transmission of the virus . The catering facility had been cited frequently for food safety and hygiene violations . None of the personnel or food handlers at this facility had been appropriately trained in safe food-handling practices, nor had the personnel at another local caterer that had prepared food items suspected of causing a multistate outbreak of NLVs . In Toledo, food service operations with trained personnel/food handlers received better inspection reports than food service operations without trained personnel and were less likely to contribute to foodborne outbreaks . Training of personnel and food handlers may be important for preventing outbreaks.

Int J Food Microbiol, 2001 Nov 8, 70(3), 231 - 42
Salmonella in slaughter pigs: the effect of logistic slaughter procedures of pigs on the prevalence of Salmonella in pork; Swanenburg M et al.; A substantial part of the finishing pigs in the Netherlands is infected with Salmonella . Infection of pigs with Salmonella can occur already on the farm . Pigs can also get infected or contaminated during transport, lairage or slaughter . The aim of this study was to evaluate the effect of separating pigs from Salmonella-infected farms from pigs from Salmonella-free farms during transport, lairage and slaughter on the prevalence of Salmonella on pork after slaughter . Two experiments were carried out . In the first experiment, farms were selected to participate, based on serology of the pigs (Dutch Salmonella ELISA) . The pigs were slaughtered at the beginning of the day: firstly, sero-negative herds, secondly, sero-positive herds and thirdly, again sero-negative herds . The latter were slaughtered to investigate the effect of a contaminated slaughterline due to a previously slaughtered positive herd . In the second experiment, farms were selected to participate, based on both serology and bacteriology of the pigs on the farm . Two hundred pigs from Salmonella-free farms were slaughtered after 200 pigs from Salmonella-infected farms . Results showed that the prevalence of Salmonella in pork samples of sero-negative herds was lower than in samples of sero-positive herds . Results also showed that Salmonella contamination of carcasses after slaughter was partially caused by Salmonella-infected herds that were slaughtered before, and partially by residential flora of the slaughterhouse . It is concluded that separate slaughter of sero-negative pig herds can be useful to decrease the prevalence of Salmonella-contaminated pork after slaughter . To avoid cross-contamination by residential flora from trucks, lairage and slaughterline, cleaning and disinfection have to be improved.

Bratisl Lek Listy, 2001, 102(8), 374 - 6
Eradicative effect of cotrimoxazole and quinolones on non-typhoid salmonellae; Wawruch M et al.; Opinions on antibiotic treatment of salmonella gastroenteritis are still different . Many authors support an opinion that antimicrobial treatment has no effect on salmonella elimination . The authors of the study have tried to prove that fluoroquinolones shorten the elimination of salmonellae and therefore they are useful not only for the treatment of salmonella gastroenteritis in immunocompromised patients to prevent sepsis and extraintestinal manifestations of the infection, but also for eradication of salmonellae in food industry workers, whose carrier state might exclude them from their work . (Tab . 3, Ref . 10.)

J Assoc Physicians India, 2001 Apr, 49, 477 - 8
An unusual paratyphoid fever; Biswas R et al.; Salmonella typhi is known to produce acalculous cholecystitis and related gall bladder perforation . Following is a documentation of a patient of sub-phrenic abscess and gall bladder perforation which was possibly a result of Salmonella paratyphi A.

Ann Oncol, 2001, 12 Suppl 2, S19 - 25
Nerve-driven immunity: neuropeptides regulate cytokine secretion of T cells and intestinal epithelial cells in a direct, powerful and contextual manner; Levite M et al.; Throughout the body, immune cells of various types, both classical (such as T-cells) and less recognized (such as intestinal epithelial cells) are exposed to a variety of neurotransmitters secreted from local nerve fibers . Moreover, immune cells express specific neurotransmitter receptors . Based on the above we asked whether neurotransmitters . by direct interaction with their receptors, can either evoke or block immune functions in general, and cytokine secretion in particular . We found that several neuropeptides (SOM, Sub P, CGRP and NPY), in nM concentration and in the absence of any additional stimulatory molecules, induced a significant secretion of cytokines from Th0, Th1 and Th2 antigen specific T-cells . Moreover, some neuropeptides surprisingly drove committed Thl and Th2 populations to a 'forbidden' cytokine secretion: secretion of Th2 cytokines from Th1 cells, and vice versa . We further found that SOM by itself markedly affected the secretion of proinflammatory cytokines from intestinal epithelial cells, which play a major role in the gut immunity in the mucosal defense against invading microorganisms . Thus, somatostatin, through its specific receptor, inhibits (> 90%) of the spontaneous, TNF-alpha or bacteria (Salmonella)-induced secretion of IL-8 and IL-1beta from two intestinal epithelial cell lines . Taken together, these observations suggest that neuropeptides can by themselves induce both typical and atypical cytokine secretion from T-cells and intestinal epithelial cells . Since a myriad of immune reactivities are mediated by, and dependent on, specific cytokines secreted from immune cells, the neuropeptide-induced effects may have important implications for numerous physiological and pathological conditions, including autoimmune diseases, chronic inflammation and neoplasias.

Przegl Epidemiol, 2001, 55(3), 261 - 73
{Collective outbreaks of foodborne infections and intoxications in Poland in 1985-1999.}; Przybylska A; In outbreaks of foodborne infections and intoxications in 1985-1999 in Poland among salmonellas S . Enteritidis amounted for 84.9% in 1986 and 97.8% in 1991-1992 . In 1985-1999, among the total number of diseases in outbreaks most of the cases occurred after eating of the dishes made from eggs (over 50%) . In 1987-1999, food prepared in private homes had the largest influence on the occurrence of the outbreaks (up to 65.4% of outbreaks) . The private homes were also the most frequent places of the consumption of that food . Contamination of the ready-made dishes was found to be due to the raw materials, mainly eggs coming from private farms . In Poland and in neighboring countries Salmonella of animal's source determines the epidemiological situation of foodborne infections and intoxications.

J Med Microbiol, 2001 Dec, 50(12), 1049 - 54
Survival and distribution of cell-free SEF 21 of Salmonella enterica serovar Enteritidis in the stomach and various compartments of the rat gastrointestinal tract in vivo; Naughton PJ et al.; Rats were dosed for 6 days with purified SEF 21 fimbriae of Salmonella enterica serovar Enteritidis 10360 . The levels of fimbriae in gut contents associated with tissues and in the faeces were quantified by direct non-competitive ELISA . SEF 21 was distributed throughout the gut . The majority was found in the large intestine where it was primarily in the luminal contents . In contrast, a high proportion of SEF 21 detected in the ileum, the main site of salmonella colonisation and invasion, was tissue-bound . Thus, purified SEF 21 survived intestinal passage and associated with the stomach and gastrointestinal tract in a pattern similar to that found with whole Salmonella cells.

Presse Med, 2001 Nov 17, 30(34), 1674 - 80
{Causes of fever in adults infected by HIV-1 . Ambulatory follow-up in the ANRS 059 trial in Abidjan, Ivory Coast}; Dakoury-Dogbo N et al.; OBJECTIVE: Describe the causes of fever in HIV-1 infected adults in Abidjan, Ivory Coast . METHODS: Exhaustive analysis of all the morbid episodes with raise in temperature to above 37.5 degrees C in patients followed-up prospectively, within the framework of the ANRS 059 study from April 1996 to March 1998 . RESULTS: One hundred and four patients presented 269 episodes of fever . At the start of these episodes, the mean CD4 count was of 311/mm3, fever had lasted a mean of 3.4 days and mean body temperature was 38.7 degrees C . The 269 episodes lead to 288 diagnoses: 152 specific etiologic diagnoses and 136 non-specific syndrome diagnoses . Community bacterial infections represented 55% of the specific diagnoses, followed by malaria (16%) and tuberculosis (12%) . The mean CD4 count during the bacterial episodes was 208/mm3, in malaria 384/mm3 and in tuberculosis 245/mm3 . Non-typhi salmonella, pneumococci and Escherischia coli represented 37%, 32%, and 15% respectively of the bacteria isolated . The mean duration between the first and last day of fever was 8.4 days . This time lapse was superior or equal to 30 days in 22 episodes (8%), 50% of which were mycobacterioses (36% tuberculosis and 14% atypic mycobacterioses) . Nineteen episodes (7%) lead to death within a mean delay of 58 days . The first cause of death was atypic mycobacteriosis (26%) . Death was significantly associated with a CD4 count < 200/mm3 and to prolongation of fever for more than 30 days . CONCLUSION: Other than the frequently described role of tuberculosis in HIV morbidity in sub-Saharian Africa, the role of bacterial diseases, responsible for early death, potentially severe, but curable should be underlined . The diffusion of antibiotic treatment algorithms adapted to the principle clinical syndromes encountered, might improve the treatment of adults infected by HIV consulting in sub-Saharian Africa.

Scand J Infect Dis, 2001, 33(11), 862 - 5
Invasive Salmonella virchow infection in childhood; Bitsori M et al.; Salmonella virchow is generally considered to be one of the less invasive non-typhoidal Salmonellae species; however, several invasive cases have previously been reported . We report 3 cases of otherwise healthy children with S . virchow bacteraemia, monoarthritis and prevertebral abscess, only 1 of whom had previously had gastroenteritis . All 3 children responded to antibiotic regimens consisting of cefotaxime for 10 d, ceftriaxone for 3 weeks and ceftriaxone plus clindamycin for 4 weeks, respectively . In conclusion, S . virchow may be a more invasive serotype in immunocompetent children and present with a wider spectrum of manifestations than considered previously.

Int J Food Microbiol, 2001 Oct 22, 70(1-2), 37 - 51
Modeling non-linear survival curves to calculate thermal inactivation of salmonella in poultry of different fat levels; Juneja VK et al.; Survival curves of a cocktail of eight serotypes of Salmonella in ground poultry of different fat levels (1-12%), when heated rapidly to specified temperatures (58-65 degrees C), were examined . Because many of the survival curves were concave, values for two parameters: the asymptotic D-value and the "lag" times were estimated and used to develop secondary models for estimating the time needed to obtain a 7 log10 relative reduction as a function of fat level and temperature . To compute the necessary time, at a given temperature and fat level, the estimated lag time should be added to the product of 7 and the estimated asymptotic D-value . A model was also developed for estimating the standard error of the estimated times, so that upper confidence bounds for the necessary times can be computed . It was found that lag times increase with higher fat levels . The effect of fat on D-values depended on the species; it is estimated that, for a given increase of fat level, the increase of the D-value would be greater for ground chicken than that for ground turkey . In addition, there was a statistically significant species effect on D-values, with higher D-values for ground turkey than for ground chicken at the higher temperatures studied . The thermal death curves displayed a non-linear tendency, however, for estimation purposes, a linear curve was assumed . There was not a statistically significant interaction effect of fat levels and temperatures on D-values, thus, for modeling, it was assumed that z-values were not dependent on the fat levels . The z-values for ground chicken and turkey were estimated to be 5.5 degrees C and 6.1 degrees C, respectively, and are statistically significantly different . These findings should have substantial practical importance to food processors of cooked poultry, allowing them to vary their thermal treatment of ready-to-eat poultry products in a safe manner.

Int J Food Microbiol, 2001 Oct 22, 70(1-2), 29 - 35
Antimicrobial susceptibilities of isolates of Staphylococcus aureus, Listeria species and Salmonella serotypes associated with poultry processing; Geornaras I et al.; The broth microdilution method was used to determine the activities of selected antimicrobial agents used in the South African poultry industry (danofloxacin, neomycin, chlortetracycline, oxytetracycline, tylosin and colistin) and vancomycin against bacterial isolates previously obtained from carcasses and selected equipment surfaces and environmental sources associated with poultry processing . The antimicrobial susceptibilities of 38 isolates of Staphylococcus (S.) aureus, 25 Listeria (L.) innocua, 18 L . monocytogenes, and 62 isolates belonging to six Salmonella (Salm.) serotypes (Salm . agona, Salm . blockley, Salm . enteritidis, Salm . isangi, Salm . reading and Salm . typhimurium) were determined . The most active antimicrobial agent against all the isolates tested was danofloxacin with minimum inhibitory concentrations (MICs) for 90% of the isolates (MIC90) not exceeding 0.25 and 2 microg/ml for gram-negative and gram-positive isolates, respectively . Conversely, high MICs were recorded for all the isolates tested against chlortetracycline and oxytetracycline (MIC90 range of 32 to > 512 microg/ml), except for the L . monocytogenes and Salm . enteritidis isolates (MIC range of < or = 0.5-4 microg/ml) . Neomycin was found to be active against S . aureus, L . innocua, L . monocytogenes, Salm . enteritidis and Salm . isangi isolates, with MICs not exceeding 8 microg/ml . MIC ranges for tylosin and vancomycin, which were only tested against the gram-positive isolates, were from 1 to > 512 microg/ml and from 1 to 4 microg/ml, respectively . The MIC range for the remaining antimicrobial agent, colistin, which was only tested against the Salmonella isolates, was 0.5-16 microg/ml . The lack of MIC breakpoints for the antimicrobial agents used in the poultry industry did not allow for definite conclusions as to the level of resistant bacteria associated with poultry carcasses and the processing environment in this study.

Int J Food Microbiol, 2001 Oct 22, 70(1-2), 131 - 41
Growth of Salmonella enteritidis in artificially contaminated eggs: the effects of inoculum size and suspending media; Cogan TA et al.; Growth profiles of two isolates of Salmonella enteritidis phage type (PT) 4 inoculated into either the albumen of whole shell eggs or into separated albumen were found to be markedly affected by the size of the inoculum and the composition of the medium used to suspend the cells prior to inoculation . Using our model with an inoculum of two cells, multiplication of the Salmonella was not seen in 93% of eggs held at 20 degrees C for 8 days . In approximately 7% of eggs, however, growth occurred during the 8 days of storage . If the inoculum equaled or exceeded 25 cells per egg when eggs were subsequently stored at 20 degrees C, or 250 cells per egg when eggs were stored at 30 degrees C, high levels of growth of Salmonella in the egg occurred significantly more frequently than when the inoculum was two cells . High levels of growth were also seen more frequently if the inoculum was suspended in buffered peptone water or maximal recovery diluent rather than in phosphate buffered saline . Growth of Salmonella in separated albumen occurred very infrequently (1.1% of samples) at low inoculum levels and did not become significant until the inoculum was 250 cells or greater . Growth in the albumen was unaffected by the composition of the suspending medium . Provided that the inoculum was approximately 2 cells per egg and the bacteria were suspended in PBS, observed growth profiles of S . enteritidis inoculated into the albumen of whole eggs resembled those in naturally contaminated eggs.

Med Dosw Mikrobiol, 2001, 53(2), 185 - 96
{Phage types, plasmid profiles and chromosomal restriction profiles of Salmonella enterica subsp . enterica ser . enteritidis (S . enteritidis) isolated in Poland in 1999-2000}; Cieslik A et al.; Salmonella Enteritidis strains are the most often isolated Salmonella serovars in Poland . In the present study, phage typing, plasmid profile analysis, and PFGE have been applied to characterize 140 Polish S . Enteritidis isolates originated from human cases of salmonellosis and from other sources . The typing phages of Ward and colleagues scheme were used to type a total of 140 S . Enteritidis strains coming from Poland . All 140 strains were typable and six different phage types were observed . A total of 125 (89%) of 140 isolates examined belonged to PT 4 . The others PTs were represented by small amount of strains (PT1-2, PT6-6, PT7-1, PT8-4 and PT21-2 strains) . Among all tested isolates six different plasmid profiles were observed . Of the 140 examined strains, 128 (91.4%) contained the 57 kb plasmid alone . After XbaI digestion four distinct pulse field chromosomal restriction profiles among studied S . Enteritidis were observed . XbaI and SpeI chromosomal restriction profiles of S . Enteritidis PT4 were identical with reference strain profiles . Our findings confirmed earlier suggestions that the increase of human salmonellosis cases in Poland was caused by S . Enteritidis PT4 and was due to consumption of contaminated food . This study confirmed the importance of using PFGE in combination with phage typing, plasmid typing and antibiotic resistance testing for studying the epidemiology of S . Enteritidis.

Med Dosw Mikrobiol, 2001, 53(1), 17 - 29
{Multidrug resistance to antibacterial drugs of Salmonella enterica subsp . enterica strains isolated in Poland in the 1998-1999 period}; Szych J et al.; A total of 510 Salmonella enterica subsp . enterica strains representing 56 serotypes, isolated from human stool specimens during 1998-2000 in sanitary-epidemiological units in Poland were tested for their susceptibility by a standard disk diffusion method for: ampicillin, cefotaxime, chloramphenicol, tetracycline, streptomycin, gentamicin, kanamycin, nalidixic acid, ciprofloxacin, furazolidone, cotrimoxazole, sulfonamides and trimethoprim . For 201 of the investigated strains, belonging to 5 most common isolated serotypes (S . Enteritidis, S . Typhimurium, S . Hadar, S . Infantis and S . Virchow) the minimal inhibitory concentrations (MICs) for the aforementioned antibiotics, as well as for amoxicillin with clavulanian were determined . Selected strains were screened for production extended spectrum b-lactamases (ESBLs) . It was observed that 42.9% of Salmonella enterica subsp . enterica strains were resistant to 2 or more antibiotics, with the highest prevalence of MDR strains among serotypes Typhimurium, Hadar and Virchow . Resistance to ampicillin, streptomycin, tetracycline, nalidixic acid, furazolidone and sulphonamides was observed most frequently . Over 93% of S . Virchow strains were resistant to furazolidone . No strains resistant to ciprofloxacin were detected according to the NCCLS guidelines, but 31.3% of isolates exhibiting reduced ciprofloxacin susceptibility (MICs ranging between 0.125 and 0.5 mg/l) . Two strains S . Mbandaka and Salmonella group D (variant motility--) were resistant to cefotaxime and probably produced ESBL.

Dev Comp Immunol, 2002 Apr, 26(3), 295 - 304
Interactions of Salmonella enterica serovar Muenchen with macrophages of the turtle Trachemys scripta scripta; Pasmans F et al.; Interactions of Salmonella with macrophages have been studied in birds and, most extensively, in mammals . In these homeothermic animals, interactions between Salmonella and macrophages are characterized by the following processes . After macropinocytosis, spacious phagosomes are formed within the macrophage . Partial inhibition of phagosome-lysosome fusion and resistance to the formation of reactive oxygen species and reactive nitrogen intermediates enable the bacterium to survive and even multiply within the host macrophage . Eventually, Salmonella will induce apoptosis of the macrophage . In this study, interactions of peritoneal macrophages of the turtle Trachemys scripta scripta with Salmonella enterica serovar Muenchen were examined in vitro . Turtle macrophages were able to phagocytise Salmonella efficiently at both 30 and 37 degrees C . Exposure of macrophages to Salmonella induced the production of reactive oxygen species, which could be partially suppressed by adding the NADPH oxidase inhibitor diphenylene iodonium . Initially, most of the intracellular bacteria were killed . However, Salmonella proved to be able to persist and multiply inside turtle macrophages at both 30 and 37 degrees C for at least 48 h, despite the production of reactive nitrogen intermediates by inducible NO synthase . Salmonella infection of turtle macrophages killed the phagocytes at both 30 and 37 degrees C . These findings demonstrate that no obvious qualitative differences exist between macrophage-Salmonella interactions from homeothermic animals and from turtles . This indicates that other factors are responsible for the different course of Salmonella infections in homeothermic and poikilothermic hosts.

Microbes Infect, 2001 Nov-Dec, 3(14-15), 1353 - 60
Gene array technology to determine host responses to Salmonella; Rosenberger CM et al.; Gene expression array technology is a powerful new tool that has already been used to expand our understanding of host-pathogen interactions . There has been a rapid increase in published reports describing use of this approach to profile host responses to pathogenic bacteria and viruses . The large number of array studies currently in progress coupled with increasing accessibility of this new technology promises a plethora of gene expression data on host response to infection in the near future . Recent insights into macrophage and epithelial cell responses to Salmonella infection garnered from array studies are outlined and used as a basis to discuss various future research directions using gene arrays that will advance the field of cellular microbiology . There is an exciting potential for the gene expression data generated in such studies to provide insights into host physiology, the pathophysiology of disease and novel therapeutics.

Microbes Infect, 2001 Nov-Dec, 3(14-15), 1345 - 52
Use of mixed infections with Salmonella strains to study virulence genes and their interactions in vivo; Beuzon CR et al.; In the Salmonella-mouse model of systemic infection, high dose inoculation results in the multiplication of many of the cells present in the inoculum, rather than the clonal amplification of a small number . This characteristic has allowed the development of methods to screen multiple strains for either virulence attenuation or gene expression within the same animal . Mixed infections with mutant and wild-type strains are used to provide a sensitive measure of virulence attenuation referred to as the competitive index . We have recently used a variation of this method, involving mixed infections of single and double mutant strains, to study virulence gene interaction in vivo.

Microbes Infect, 2001 Nov-Dec, 3(14-15), 1335 - 44
Animal models of Salmonella infections: enteritis versus typhoid fever; Santos RL et al.; The most common disease syndromes caused by Salmonella serotypes in humans, typhoid fever and enteritis, can be modeled using Salmonella enterica serotype Typhimurium infections in mice and calves, respectively . This article reviews murine typhoid and bovine enteritis and discusses strengths, limitations and distinctive features of these animal models.

Microbes Infect, 2001 Nov-Dec, 3(14-15), 1321 - 6
Salmonella and apoptosis: to live or let die?
Knodler LA, Finlay BB.
A successful pathogen manipulates its host for its own benefit . One means to establish a successful infection, especially for intracellular pathogens, is to exploit host cell death pathways and alter the viability of host cells . Here we describe the manipulation of apoptosis by Salmonella and discuss the advantages that such actions may confer to the bacteria, and its implications in resistance to disease.

Microbes Infect, 2001 Nov-Dec, 3(14-15), 1313 - 20
Salmonella evasion of the NADPH phagocyte oxidase; Vazquez-Torres A et al.; The bacteria-phagocyte interaction is of central importance in Salmonella pathogenesis . Immediately following phagocytosis, the NADPH phagocyte oxidase complex assembles in vesicles and produces highly toxic reactive oxygen species that play a major role in initial Salmonella killing by phagocytes . However, Salmonella has evolved a number of strategies to reduce the efficacy of oxygen-dependent phagocyte antimicrobial systems . Some of these strategies, such as superoxide dismutases, hydroperoxidases, oxidoreductases, scavengers and repair systems are common to most aerobic bacteria . In addition, Salmonella has acquired, by horizontal gene transfer, a type III secretory system encoded by Salmonella pathogenicity island 2 that interferes with the trafficking of vesicles containing functional NADPH phagocyte oxidase to the phagosome, thereby enhancing the survival of Salmonella within macrophages.

Microbes Infect, 2001 Nov-Dec, 3(14-15), 1305 - 11
Salmonella intracellular proliferation: where, when and how?
Garcia-del Portillo F.
Salmonella species proliferate within membrane-bound vacuoles of eukaryotic cells . Recent work has shown that macrophages are the main cell type supporting bacterial growth in vivo . In contrast, tissue culture models have traditionally described epithelial cells as the most permissive cells for bacterial growth . Unfortunately, no mechanism used by Salmonella to initiate growth within a vacuole has been characterised . Recently, it has been shown that Salmonella is capable of attenuating intracellular proliferation . This finding suggests that both the host and the pathogen contribute to a fine adjustment of the intracellular growth rate.

Microbes Infect, 2001 Nov-Dec, 3(14-15), 1299 - 303
Maturation steps of the Salmonella-containing vacuole; Gorvel JP et al.; After uptake, Salmonella resides within a unique organelle, the Salmonella-containing vacuole (SCV) in which it eventually replicates . Here we recapitulate the knowledge about how Salmonella controls SCV maturation and the different steps of its intracellular trafficking.

Microbes Infect, 2001 Nov-Dec, 3(14-15), 1293 - 8
Salmonella entry into host cells: the work in concert of type III secreted effector proteins; Zhou D et al.; Upon contact with intestinal epithelial cells, Salmonella enterica serovar spp . inject a set of bacterial proteins into host cells via the bacterial SPI-1 type III secretion system . SopE, SopE2 and SopB, activate CDC42 and Rac to initiate actin cytoskeleton rearrangements . SipA and SipC, two Salmonella actin-binding proteins, directly modulate host actin dynamics to facilitate bacterial uptake . SptP promotes the recovery of the actin cytoskeleton rearrangements by antagonizing CDC42 and Rac . Therefore, Salmonella-induced reversible actin cytoskeleton rearrangements are the result of two coordinated steps: (i) stimulation of host signal transduction to indirectly promote actin rearrangements and (ii) direct modulation of actin dynamics.

Microbes Infect, 2001 Nov-Dec, 3(14-15), 1281 - 91
The Salmonella pathogenicity island-1 type III secretion system; Lostroh CP et al.; Salmonella pathogenicity island 1 (SPI1) encodes a type III secretion system that is required for virulence during the intestinal phase of infection . The expression of SPI1 genes is controlled by many global regulatory pathways that affect the expression/activity of transcriptional regulators encoded on SPI1.

Microbes Infect, 2001 Nov-Dec, 3(14-15), 1271 - 9
Host-Salmonella interaction: human trials; Levine MM et al.; Human clinical trials, including experimental challenges of volunteers with pathogenic Salmonella enterica serovar Typhi, small phase I and II trials that monitor the immune responses to vaccines, and large-scale controlled field trials that assess vaccine efficacy under conditions of natural challenge, have helped elucidate the interactions between Salmonella typhi and human hosts.

Microbes Infect, 2001 Nov-Dec, 3(14-15), 1233 - 7
Polymorphonuclear leukocytes and innate immunity to Salmonella infections in mice; Fierer J; Neutropenia makes normal mice more susceptible to infection with spv (+) but not spv (-) Salmonella dublin . This shows the important role of polymorphonuclear leukocytes in resistance to Salmonella that can grow in host macrophages . Polymorphonuclear leukocytes, part of the innate immune system, kill Salmonella in a complement-dependent manner, and work in concert with macrophages.

Microbes Infect, 2001 Nov-Dec, 3(14-15), 1223 - 31
Implications of Salmonella-induced nitric oxide (NO) for host defense and vaccines: NO, an antimicrobial, antitumor, immunosuppressive and immunoregulatory molecule; Eisenstein TK; Attenuated Salmonella induce immunosuppressive, microbicidal and tumoricidal macrophages in mice . All three effects are mediated by activated macrophages producing nitric oxide (NO) . NO is induced by the innate immune response pathway involving IL-12, NK cells and IFN-gamma in response to infection . NO has beneficial and detrimental effects on the host.

Microbes Infect, 2001 Nov-Dec, 3(14-15), 1191 - 200
Cytokines in host defense against Salmonella; Eckmann L et al.; Cytokines are key communication molecules between host cells in the defense against the enteric pathogen, Salmonella . Infection with Salmonella induces expression of multiple chemokines and proinflammatory cytokines in cultured intestinal epithelial cells and macrophages . In animal models, protective roles have been shown for IL-1alpha, TNFalpha, IFN-gamma, IL-12, IL-18 and IL-15, whereas IL-4 and IL-10 inhibit host defenses against Salmonella.

Microbes Infect, 2001 Nov-Dec, 3(14-15), 1183 - 90
The role of M cells in Salmonella infection; Jepson MA et al.; Intestinal M cells, the specialised antigen-sampling cells of the mucosal immune system, are exploited by Salmonella and other pathogens as a route of invasion . Salmonella entry into M cells and colonisation of Peyer's patches involve mechanisms critical for infection of cultured cells as well as factors not accurately modelled in vitro.

Microbes Infect, 2001 Nov-Dec, 3(14-15), 1177 - 81
Introduction: microbiology and immunology: lessons learned from Salmonella; Kaufmann SH et al.; Salmonella enterica, a Gram-negative bacterium, causes significant morbidity and mortality worldwide, and is an excellent model to study bacterial pathogenesis and cellular immune responses . With the development of powerful new technologies, there has been a fusion of research on immunology, molecular biology and cellular microbiology of S . enterica infections . This multidisciplinary research will enhance our understanding of the basic mechanisms of bacterial infections and immunity; it also provides new approaches towards therapeutic and control measures.

BioDrugs . 2001;15 Suppl 1:27.
Evaluation of a new Vi polysaccharide typhoid vaccine in children aged 2-5 years; Cordero-Yap L et al.; Typhoid fever is a major cause of morbidity and mortality in many parts of the world . In view of the increasing resistance of Salmonella typhi against antibiotics and the high costs associated with improving sanitation conditions, vaccination programs would be of great benefit . We report on the evaluation of a new candidate VI (sic) polysaccharide typhoid vaccine (TypheriX (sic), SmithKline Beecham Pharmaceuticals), tested in Filipino children aged 2-5 years where the profile was compared with that of a competitor-vaccine (Typhim (sic), Pasteur Merieux Connaught) . Vaccination with the new candidate vaccine was followed by fewer general symptoms (2.9%) than with the competitor vaccine (14.1%), particularly with lower incidence of fever . The new candidate vaccine is also highly immunogenic: >99% of the vacinees were immune 28 days post vaccination with comparable GMTs of 3597 EL.U/ml for TypheriX (sic) and 3365 EL.U/ml for Typhim (sic) . This trial shows that the available VI (sic) polysaccharide vaccines provide a reliable means in preventing a disease responsible for a significant morbidity and placing a heavy burden on health budgets.

Am J Hum Genet, 2002 Feb, 70(2), 336 - 48 Epub 2001 Dec 17.
Inherited interleukin-12 deficiency: IL12B genotype and clinical phenotype of 13 patients from six kindreds; Picard C et al.; Interleukin-12 (IL12) is a cytokine that is secreted by activated phagocytes and dendritic cells and that induces interferon-gamma production by natural-killer and T lymphocytes . It consists of two subunits, p35 and p40, which are encoded by IL12A and IL12B, respectively . The first reported patient with a genetic cytokine disorder was a Pakistani child, who was homozygous for a large loss-of-function deletion (g.482+82_856-854del) in IL12B . This IL12-deficient child suffered from infections caused by bacille Calmette-Guerin (BCG) and Salmonella enteritidis . We herein report 12 additional patients from five other kindreds . In one kindred from India, the same large deletion that was described elsewhere (g.482+82_856-854del) was identified . In four kindreds from Saudi Arabia, a recessive loss-of-function frameshift insertion (g.315_316insA) was found . A conserved haplotype encompassing the IL12B gene suggested that a founder effect accounted for the recurrence of each mutation . The two founder mutational events-g.482+82_856-854del and g.315_316insA-were estimated to have occurred approximately 700 and approximately 1,100 years ago, respectively . Among a total of 13 patients with IL12 deficiency, 1 child had salmonellosis only and 12 suffered from clinical disease due to BCG or environmental nontuberculous mycobacteria . One patient also had clinical disease caused by virulent Mycobacterium tuberculosis, five patients had clinical disease caused by Salmonella serotypes, and one patient had clinical disease caused by Nocardia asteroides . The clinical outcome varies from case to case, since five patients (aged 2-11 years) died of overwhelming infection, whereas eight patients (aged 3-12 years) are still in good health and are not currently taking antibiotics . In conclusion, IL12 deficiency is not limited to a single kindred, shows significant variability of outcome, and should be considered in the genetic diagnosis of patients with mycobacteriosis and/or salmonellosis . To date, two founder IL12B mutations have been identified, accounting for the recurrence of a large deletion and a small insertion within populations from the Indian subcontinent and from the Arabian Peninsula, respectively.

J Endotoxin Res, 2001, 7(6), 447 - 50
LBP, CD14, TLR4 and the murine innate immune response to a peritoneal Salmonella infection; Bernheiden M et al.; In mice, defense against an intraperitoneal Salmonella infection depends on a vigorous innate immune response . Mutations which lead to an inadequate early response to the pathogen thus identify genes involved in innate immunity . The best studied host resistance factor, NRAMP-1, is an endosomal membrane protein whose loss leads to an inability of the animals to hold the infection in check . However, innate defense against Salmonella is not restricted to mechanisms which directly attack the pathogen within macrophages . Here we have examined the contribution of the LBP, CD14 and TLR4 gene products to innate defense against Salmonella . To this end, we have generated mice which carry a wild-type allele of NRAMP-1, but which are deficient for the LBP, CD14 or TLR4 genes . Loss of any of these genes leads to a susceptibility to Salmonella as dramatic as that seen in animals lacking functional NRAMP-1 protein . This indicates that LBP, CD14 and TLR4 are all critical elements required in the proper induction of this innate defense system.

J Endotoxin Res, 2001, 7(6), 421 - 9
Differential clearance and induction of host responses by various administered or released lipopolysaccharides; Hasunuma R et al.; The clearance and activity of different types of lipopolysaccharide (LPS) released during infection with Gram-negative bacteria were investigated . When highly purified preparations differing in their specific endotoxin activity were administered intravenously to mice, the clearance of rough (R)-form LPS preparations from Salmonella minnesota and Escherichia coli was much faster than that of a smooth (S)-form LPS preparation from Salmonella abortus equi, but slower than that of lipo-oligosaccharides (LOS) preparations from Bordetella pertussis and Helicobacter pylori . After intraperitoneal infection with 10(7) and 10(8) CFU E . coli O111:B4, relatively high levels of LPS were detected dose-dependently in the plasma of infected mice and persisted for a long time . In addition, plasma sCD14 levels in infected mice were higher than in LPS-administered mice . These results indicate that continuously higher levels of plasma LPS followed by stronger host responses occur during infection and suggest that these differences between LPS-administered and infected mice should be taken into consideration when analyzing host responses induced by LPS.

Mutagenesis, 2002 Jan, 17(1), 63 - 6
Modulation of mutagenic activity in meat samples after deep-frying in vegetable oils; Perez C et al.; Previous studies have been carried out on the influence of frying fats on the formation of food mutagens, but most of them have been performed on model systems or under cooking conditions that are more frequent in northern countries . The objective of this work was to study the overall mutagenic activity generated in hamburgers and frankfurters deep-fried under cooking conditions that are normal practice in Spain and other Mediterranean countries, in order to determine if there was any modulation of the mutagenic activity with respect to other cooking conditions previously studied . Hamburgers were prepared from beef purchased in a butcher's shop . Frankfurters as well as the oils {olive, marc olive ('orujo'), sunflower and soya bean oil} and butter were purchased in a local supermarket . The samples were fried in a teflon-coated frying pan at 170-180 degrees C for 10, 20 or 30 min . The mutagens were extracted and the mutagenic activity evaluated using the Salmonella mammalian microsome assay with strain TA98 . Two independent assays were carried out for each experimental condition . All the hamburgers showed a mutagenic activity that was more than four times higher than that of the controls . Frankfurters showed a lower mutagenic activity than hamburgers (fried under the same conditions) because they have a lower protein content and a higher fat content . Hamburgers fried in olive oil for 10 min showed a significant increase in the number of revertants with respect to the other oils, probably due to the fact that the temperature reached was approximately 10 degrees C higher . Longer frying times significantly increased the number of revertants in samples fried in oils, except in olive oil, probably due to its lower content of polyunsaturated fatty acids.

J Bacteriol, 2002 Jan, 184(2), 592 - 5
Role of the RecBCD recombination pathway in Salmonella virulence; Cano DA et al.; Mutants of Salmonella enterica lacking the RecBC function are avirulent in mice and unable to grow inside macrophages (N . A . Buchmeier, C . J . Lipps, M . Y . H . So, and F . Heffron, Mol . Microbiol . 7:933-936, 1993) . The virulence-related defects of RecBC(-) mutants are not suppressed by sbcB and sbcCD mutations, indicating that activation of the RecF recombination pathway cannot replace the virulence-related function(s) of RecBCD . Functions of the RecF pathway such as RecJ and RecF are not required for virulence . Since the RecBCD pathway, but not the RecF pathway, is known to participate in the repair of double-strand breaks produced during DNA replication, we propose that systemic infection by S . enterica may require RecBCD-mediated recombinational repair to prime DNA replication inside phagocytes . Mutants lacking both RecD and RecJ are also attenuated in mice and are unable to proliferate in macrophages, suggesting that exonucleases V and IX provide alternative functions for RecBCD-mediated recombinational repair during Salmonella infection.

FEMS Microbiol Lett, 2001 Dec 18, 205(2), 315 - 22
Computational analysis of the transcriptional regulation of pentose utilization systems in the gamma subdivision of Proteobacteria; Laikova ON et al.; The comparative approach to the recognition of transcription regulatory sites is based on the assumption that as long as a regulator is conserved in several genomes, one can expect that sets of co-regulated genes (regulons) and regulatory sites for the regulator in these genomes are conserved as well . We used this approach to analyze the ribose (RbsR), arabinose (AraC), and xylose (XylR) regulons of gamma Proteobacteria for which (almost) completely sequenced genomes were available . Candidate binding sites for RbsR and AraC were detected . The improved XylR site consensus was proposed . Potential new members of the xylose regulons were found in the Escherichia coli, Salmonella typhi, and Klebsiella pneumoniae genomes . The function of these new xylose-regulated operons is likely to be the utilization of oligosaccharides containing xylose . Finally, candidate cAMP receptor-protein sites were identified in the regulatory regions of the majority of RbsR-, AraC-, and XylR-regulated operons.

Infect Immun, 2002 Jan, 70(1), 199 - 203
Characterization of the murine T-lymphocyte response to Salmonella enterica serovar Typhimurium infection; Mittrucker HW et al.; Infection of mice with Salmonella enterica serotype Typhimurium induces a strong Th1 cell response that is central for the control of infection . We infected mice of a resistant background with a virulent strain of S . enterica serovar Typhimurium and analyzed the kinetics and magnitude of the T-cell response . After infection, the majority of CD4(+) and CD8(+) splenocytes acquired an activated phenotype, as indicated by expression levels of CD44 and CD62L . In addition, after 3 to 4 weeks of infection, more than 20% of the CD4(+) and more than 30% of the CD8(+) T cells produced gamma interferon (IFN-gamma) in response to short-term polyclonal stimulation . In contrast, we detected only a moderate (two- to threefold) expansion of both T-cell populations, and BrdU incorporation revealed that there was either no or only a limited increase in the in vivo proliferation of CD4(+) and CD8(+) T cells, respectively . Our results indicate that although an unexpectedly large population of both CD4(+) and CD8(+) T cells is activated and acquires the potential to secrete IFN-gamma, this activation is not paralleled by substantial expansion of these T-cell populations.

Infect Immun, 2002 Jan, 70(1), 192 - 8
Comparison of inflammation, organ damage, and oxidant stress induced by Salmonella enterica serovar Muenchen flagellin and serovar Enteritidis lipopolysaccharide; Liaudet L et al.; Gram-negative sepsis is related to the activation of interconnected inflammatory cascades in response to bacteria and their products . Recent work showed that flagellin, the monomeric subunit of bacterial flagella, triggers innate immune responses mediated by Toll-like receptor 5 . Here, we compared the effects of Salmonella enterica serovar Enteritidis lipopolysaccharide (LPS) and recombinant Salmonella enterica serovar Muenchen flagellin administered intravenously (100 microg) to mice . Flagellin and LPS both elicited a prototypical systemic inflammatory response, with increased levels of tumor necrosis factor alpha, gamma interferon, interleukin 6 and 10, and nitrate in plasma . Flagellin induced a widespread oxidative stress, evidenced by an increase in malondialdehyde and a decrease in reduced glutathione in most organs, as well as liver (increased plasma aminotransferases), but not renal, injury . Alternatively, LPS resulted in a less severe oxidative stress and triggered renal, but not liver, damage . Sequestration of polymorphonuclear neutrophils (increased myeloperoxidase activity) in the lungs was observed with both toxins, while only LPS recruited neutrophils in the gut . In additional experiments, the simultaneous administration of small doses of LPS and flagellin (10 microg) induced a synergistic enhancement of the production of proinflammatory cytokines . Our data support a novel concept implicating flagellin as a mediator of systemic inflammation, oxidant stress, and organ damage induced by gram-negative bacteria.

Infect Immun, 2002 Jan, 70(1), 86 - 95
Proteolytic inhibition of Salmonella enterica serovar typhimurium-induced activation of the mitogen-activated protein kinases ERK and JNK in cultured human intestinal cells; Mynott TL et al.; Bromelain, a mixture of cysteine proteases from pineapple stems, blocks signaling by the mitogen-activated protein (MAP) kinases extracellular regulated kinase 1 (ERK-1) and ERK-2, inhibits inflammation, and protects against enterotoxigenic Escherichia coli infection . In this study, we examined the effect of bromelain on Salmonella enterica serovar Typhimurium infection, since an important feature of its pathogenesis is its ability to induce activation of ERK-1 and ERK-2, which leads to internalization of bacteria and induction of inflammatory responses . Our results show that bromelain dose dependently blocks serovar Typhimurium-induced ERK-1, ERK-2, and c-Jun NH(2)-terminal kinase (JNK) activation in Caco-2 cells . Bromelain also blocked signaling induced by carbachol and anisomycin, pharmacological MAP kinase agonists . Despite bromelain inhibition of serovar Typhimurium-induced MAP kinase signaling, it did not prevent subsequent invasion of the Caco-2 cells by serovar Typhimurium or alter serovar Typhimurium -induced decreases in resistance across Caco-2 monolayers . Surprisingly, bromelain also did not block serovar Typhimurium-induced interleukin-8 (IL-8) secretion but synergized with serovar Typhimurium to enhance IL-8 production . We also found that serovar Typhimurium does not induce ERK phosphorylation in Caco-2 cells in the absence of serum but that serovar Typhimurium-induced invasion and decreases in monolayer resistance are unaffected . Collectively, these data indicate that serovar Typhimurium-induced invasion of Caco-2 cells, changes in the resistance of epithelial cell monolayers, and IL-8 production can occur independently of the ERK and JNK signaling pathways . Data also confirm that bromelain is a novel inhibitor of MAP kinase signaling pathways and suggest a novel role for proteases as inhibitors of signal transduction pathways in intestinal epithelial cells.

Emerg Infect Dis, 2001 Nov-Dec, 7(6), 1046 - 8
A multistate outbreak of Salmonella enterica serotype Baildon associated with domestic raw tomatoes; Cummings K et al.; Salmonella enterica serotype Baildon, a rare serotype, was recovered from 86 persons in eight states; 87% of illnesses began during a 3-week period ending January 9, 1999 . Raw restaurant-prepared tomatoes were implicated in multiple case-control studies . Contamination likely occurred on the farm or during packing; more effective disinfection and prevention strategies are needed.

Emerg Infect Dis, 2001 Nov-Dec, 7(6), 996 - 1003
Reduced fluoroquinolone susceptibility in Salmonella enterica serotypes in travelers returning from Southeast Asia; Hakanen A et al.; During 1995 to 1999, we collected 1,210 Salmonella isolates; 629 were from Finnish travelers returning from abroad . These isolates were tested for susceptibility by determining MICs to ciprofloxacin, nalidixic acid, and seven additional antimicrobial agents . From 1995 to 1999, the annual proportion of reduced ciprofloxacin susceptibility (MIC > 0.125 microg/mL) among all travelers' isolates increased from 3.9% to 23.5% (p<0.001) . The increasing trend was outstanding among the isolates from Southeast Asia; isolates from Thailand alone increased from 5.6% to 50.0% (p<0.001) . The reduced fluoroquinolone susceptibility was nonclonal in character and significantly associated with multidrug resistance . A point mutation in the quinolone resistance-determining region of gyrA was present in all isolates with reduced susceptibility . These data provide further evidence for the rapid spread of multidrug-resistant pathogens from one continent to another.

Microb Pathog, 2001 Dec, 31(6), 283 - 93
An inhibitory factor for cell-free protein synthesis from Salmonella enteritidis exhibits cytopathic activity against Chinese hamster ovary cells; Iwamaru Y et al.; A factor inhibiting cell-free protein synthesis was purified from Salmonella enteritidis cell lysate by sequential ammonium sulfate precipitation, chromatography on anion exchange and hydrophobic interaction columns, and polyacrylamide disc gel electrophoresis . The purified factor, which was named SIPS (Salmonella inhibitor of protein synthesis), inhibited in vitro protein synthesis in rabbit reticulocyte lysate and had a molecular mass of 38 kDa, estimated by PAGE under denaturing conditions . SIPS was also cytopathic for Chinese hamster ovary cells . The N-terminal amino acid sequence (20 residues) of SIPS was found to be identical to that of mature L-asparaginase II of Escherichia coli . Indeed, the purified SIPS exhibited asparaginase activity, E . coli L-asparaginase II had cytopathic activity and inhibited in vitro protein synthesis . The results suggest that at least a part of cytotoxicity and inhibition of cell-free protein synthesis caused by S . enteritidis is a property of the bacterial L-asparaginase .

J Acquir Immune Defic Syndr, 2001 Dec 15, 28(5), 478 - 86
HIV-1-related morbidity in adults, Abidjan, Côte d'Ivoire: a nidus for bacterial diseases; Attia A et al.; We studied mortality and morbidity in 270 HIV-1-infected adults (60% women, median age 31 years, mean baseline CD4 count 331/mm(3) ) observed in a follow-up that lasted a median 10 months in Cote d'Ivoire . Survival and probability of remaining free from any episode of morbidity at 12 months were 0.80 and 0.50, respectively . Baseline CD4 count <200/mm(3) was the only variable associated with global morbidity and mortality, with hazard ratios of 2.50 and 7.57, respectively . The most frequent causes of morbidity were severe bacterial infections (incidence rate: 26.1 per 100 person-years {py}), followed by oral candidiasis (22.3% py), unexplained weight loss over 10% of baseline body weight (13.3% py), tuberculosis (10.1% py), unexplained chronic diarrhea (9.7% py), and isosporiasis (5.1% py) . Nontyphoid Salmonella accounted for 37% of isolated strains during severe bacterial infections, followed by Streptococcus pneumoniae (34%), Escherichia coli (15%), and Shigella species (7%) . A significant part of bacterial morbidity occurred in patients with baseline CD4 count > or = 200/mm(3), in whom the incidence rate of bacterial diseases was 21.3% py and the probability of remaining free from any bacterial infection at 12 months was 0.80 (vs . 36.4% py and 0.71 in patients with baseline CD4 count <200/mm(3); p =.07).

J Agric Food Chem, 2001 Dec, 49(12), 5750 - 4
Naturally occurring anti-Salmonella agents; Kubo I et al.; Polygodial and (2E)-hexenal were found to possess antibacterial activity against Salmonella choleraesuis with the minimum bactericidal concentrations (MBC) of 50 microg/mL (0.17 mM) and 100 microg/mL (0.98 mM), respectively . The time kill curve study showed that these two alpha,beta-unsaturated aldehydes were bactericidal against this food-borne bacterium at any stage of growth . However, they showed different effects on the growth of S . choleraesuis . The combination of polygodial and anethole exhibited strong synergism on their bacteriostatic action but only marginal synergism on their bactericidal action.

Proc Natl Acad Sci U S A, 2001 Dec 18, 98(26), 15264 - 9 Epub 2001 Dec 11.
Epitope tagging of chromosomal genes in Salmonella; Uzzau S et al.; We have developed a simple and efficient procedure for adding an epitope-encoding tail to one or more genes of interest in the bacterial chromosome . The procedure is a modification of the gene replacement method of Datsenko and Wanner {Datsenko, K . A . & Wanner, B . L . (2000) Proc . Natl . Acad . Sci . USA 97, 6640-6645} . A DNA module that begins with the epitope-encoding sequence and includes a selectable marker is amplified by PCR with primers that carry extensions (as short as 36 nt) homologous to the last portion of the targeted gene and to a region downstream from it . Transformation of a strain expressing bacteriophage lambda red functions yields recombinants carrying the targeted gene fused to the epitope-encoding sequence . The resulting C-terminal-tagged protein can be identified by standard immuno-detection techniques . In an initial application of the method, we have added the sequences encoding the FLAG and 3xFLAG and influenza virus hemagglutinin epitopes to various genes of Salmonella enterica serovar Typhimurium, including putative and established pathogenic determinants present in prophage genomes . Epitope fusion proteins were detected in bacteria growing in vitro, tissue culture cells, and infected mouse tissues . This work identified a prophage locus specifically expressed in bacteria growing intracellularly . The procedure described here should be applicable to a wide variety of Gram-negative bacteria and is particularly suited for the study of intracellular pathogens.

J Bacteriol, 2002 Jan, 184(1), 307 - 12
Transduction-mediated transfer of unmarked deletion and point mutations through use of counterselectable suicide vectors; Kang HY et al.; A challenge in strain construction is that unmarked deletion and nucleotide substitution alleles generally do not confer selectable phenotypes . We describe here a rapid and efficient strategy for transferring such alleles via generalized transduction . The desired allele is first constructed and introduced into the chromosome by conventional allelic-exchange methods . The suicide vector containing the same allele is then integrated into the mutant chromosome, generating a tandem duplication homozygous for that allele . The resulting strain is used as a donor for transductional crosses, and selection is made for a marker carried by the integrated suicide vector . Segregation of the tandem duplication results in haploid individuals, each of which carries the desired allele . To demonstrate this mutagenesis strategy, we used bacteriophage P22HTint for generalized transduction-mediated introduction of unmarked mutations to Salmonella enterica serovar Typhimurium . This method is applicable to any species for which generalized transduction is established.

J Bacteriol, 2002 Jan, 184(1), 224 - 32
The ATP-dependent lon protease of Salmonella enterica serovar Typhimurium regulates invasion and expression of genes carried on Salmonella pathogenicity island 1; Takaya A et al.; An early step in the pathogenesis of Salmonella enterica serovar Typhimurium infection is bacterial penetration of the intestinal epithelium . Penetration requires the expression of invasion genes found in Salmonella pathogenicity island 1 (SPI1) . These genes are controlled in a complex manner by regulators in SPI1, including HilA and InvF, and those outside SPI1, such as two-component regulatory systems and small DNA-binding proteins . We report here that the expression of invasion genes and the invasive phenotype of S . enterica serovar Typhimurium are negatively regulated by the ATP-dependent Lon protease, which is known to be a major contributor to proteolysis in Escherichia coli . A disrupted mutant of lon was able to efficiently invade cultured epithelial cells and showed increased production and secretion of three identified SPI1 proteins, SipA, SipC, and SipD . The lon mutant also showed a dramatic enhancement in transcription of the SPI1 genes hilA, invF, sipA, and sipC . The increases ranged from 10-fold to almost 40-fold . It is well known that the expression of SPI1 genes is also regulated in response to several environmental conditions . We found that the disruption of lon does not abolish the repression of hilA and sipC expression by high-oxygen or low-osmolarity conditions, suggesting that Lon represses SPI1 gene expression by a regulatory pathway independent of these environmental signals . Since HilA is thought to function as a central regulator of SPI1 gene expression, it is speculated that Lon may regulate SPI1 gene expression by proteolysis of putative factors required for activation of hilA expression.

Bioorg Med Chem, 2002 Feb, 10(2), 269 - 72
Antimicrobial and anti-lipase activity of quercetin and its C2-C16 3-O-acyl-esters; Gatto MT et al.; Neither quercetin (Q), nor 3-O-acylquercetines, up to 100 microg/mL, had any significant activity on selected gram-positive strains (Staphylococcus aureus, Bacillus subtilis, Listeria ivanovi, Listeria monocytogenes, Listeria serligeri), gram-negative strains (Escherichia coli, Shigella flexneri, Shigella sonnei, Salmonella enteritidis, Salmonella tiphymurium) and yeasts (Candida albicans and Candida glabrata) . In addition, we confirmed the known anti-HIV activity of Q (80% inhibition at 40 microM), which might depend on the free hydroxyl in the C-3 position, as suggested by the lack of activity of the 3-O-acylquercetines . Finally, we described an interesting inhibitory activity on Candida rugosa lipase by Q (IC(16)=10(-4) M) and its esters (3-O-acylquercetines) which, in vivo, could play an important role against lipase producing microorganisms . In particular, 3-O-acyl-quercetines, being more active (IC(16)=10(-4)-10(-6) M) and more lipophilic, could be more effective than Q when applied to the skin or mucosae, and deserve to be studied further.

J Immunol, 2001 Dec 15, 167(12), 7009 - 16
Salmonella flagellin-dependent proinflammatory responses are localized to the conserved amino and carboxyl regions of the protein; Eaves-Pyles TD et al.; Flagellin, the monomeric subunit of flagella, is an inducer of proinflammatory mediators . Bacterial flagellin genes have conserved domains (D1 and D2) at the N terminus and C terminus and a middle hypervariable domain (D3) . To identify which domains induced proinflammatory activity, r6-histidine (6HIS)-tagged fusion constructs were generated from the Salmonella dublin (SD) fliC flagellin gene . A full-length r6HIS SD flagellin (6HIS flag) induced IkappaBalpha loss poststimulation and NF-kappaB activation in Caco-2BBe cells and was as potent as native-purified SD flagellin . IFN-gamma-primed DLD-1 cells stimulated with 1 microg/ml of 6HIS flag induced high levels of NO (60 +/- 0.95 microM) comparable to the combination of IL-1beta and IFN-gamma (77 +/- 1.2) or purified native SD flag (66.3 +/- 0.98) . Selected rSD flagellin proteins representing the D1, D2, or D3 domains alone or in combination were tested for proinflammatory properties . Fusion proteins representing the D3, amino, or carboxyl regions alone did not induce proinflammatory mediators . The results with a recombinant protein containing the amino D1 and D2 and carboxyl D1 and D2 separated by an Escherichia coli hinge (ND1-2/ECH/CD2) indicated that D1 and D2 were bioactive when coupled to an ECH element to allow protein folding . This chimera, but not the hinge alone, induced IkappaBalpha degradation, NF-kappaB activation, and NO and IL-8 production in two intestinal epithelial cell lines . ND1-2/ECH/CD2-1 also induced high levels of TNF-alpha (900 pg/ml) in human monocytes comparable to native SD flagellin (991.5 pg/ml) and 6HIS flag (987 pg/ml) . The potent proinflammatory activity of flagellin, therefore, resides in the highly conserved N and C D1 and D2 regions.

Vaccine, 2001 Dec 12, 20(5-6), 845 - 52
Safety and immunogenicity of live recombinant Salmonella enterica serovar Typhi Ty21a expressing urease A and B from Helicobacter pylori in human volunteers; Bumann D et al.; Helicobacter pylori urease was expressed in the common live typhoid vaccine Ty21a yielding Ty21a(pDB1) . Nine volunteers received Ty21a(pDB1) and three control volunteers received Ty21a . No serious adverse effects were observed in any of the volunteers . Ten out of 12 volunteers developed humoral immune responses to the Salmonella carrier as detected by antigen-specific antibody-secreting cells but only two volunteers seroconverted . A total of five volunteers showed responses in one or two out of three assays for cellular responses to the carrier (proliferation, IFN-gamma-secretion, IFN-gamma-ELISPOT) . Three of the volunteers that had received Ty21a(pDB1) showed a weak but significant T-cell response to Helicobacter urease, while no volunteer had detectable humoral responses to urease . Ty21a(pDB1) is a suitable prototype to optimize Salmonella-based vaccination for efficient cellular responses that could mediate protective immunity against Helicobacter.

Cell Microbiol, 2001 Dec, 3(12), 865 - 71
The filamentous type III secretion translocon of enteropathogenic Escherichia coli; Daniell SJ et al.; Enteropathogenic Escherichia coli (EPEC) uses a type III secretion system (TTSS) to inject effector proteins into the plasma membrane and cytosol of infected cells . To translocate proteins, EPEC, like Salmonella and Shigella, is believed to assemble a macromolecular complex (type III secreton) that spans both bacterial membranes and has a short needle-like projection . However, there is a special interest in studying the EPEC TTSS owing to the fact that one of the secreted proteins, EspA, is assembled into a unique filamentous structure also required for protein translocation . In this report we present electron micrographs of EspA filaments which reveal a regular segmented substructure . Recently we have shown that deletion of the putative structural needle protein, EscF, abolished protein secretion and formation of EspA filaments . Moreover, we demonstrated that EspA can bind directly to EscF, suggesting that EspA filaments are physically linked to the EPEC needle complex . In this paper we provide direct evidence for the association between an EPEC bacterial membrane needle complex and EspA filaments, defining a new class of filamentous TTSS.

Cell Microbiol, 2001 Dec, 3(12), 795 - 810
Role of tyrosine kinases and the tyrosine phosphatase SptP in the interaction of Salmonella with host cells; Murli S et al.; Salmonella has evolved an intimate functional interface with its host . Central to this interface is a battery of bacterial proteins delivered into host cells via a specialized organelle termed the type III secretion system . A subset of these bacterial proteins stimulates cellular responses by activating the Rho family GTPases Cdc42 and Rac . Stimulation of these responses leads to actin cytoskeleton reorganization and the activation of cellular transcription factors that result in bacterial uptake and proinflammatory cytokine production . Remarkably, the cellular responses stimulated by Salmonella are quickly reversed by another bacterial protein, SptP, which exerts its function as a GTPase-activating protein (GAP) for Cdc42 and Rac . In addition to its GAP activity located within its amino-terminus, the carboxy-terminal domain of SptP possesses potent tyrosine phosphatase activity . We show here that the tyrosine phosphatase activity of SptP is involved in reversing the MAP kinase activation that results from Salmonella infection . We also demonstrate an important role for tyrosine kinases, including ACK, in the cellular responses induced by Salmonella . We also found that a potential target for the tyrosine phosphatase activity of SptP is the intermediate filament protein vimentin, which is recruited to the membrane ruffles stimulated by Salmonella.

Pediatr Infect Dis J, 2001 Aug, 20(8), 792 - 7
Asymptomatic salmonellosis among children in day-care centers in Mérida, Yucatan, Mexico; Oberhelman RA et al.; BACKGROUND: Child day-care centers (DCC) have become common in many lower and middle income countries, presenting new problems that may differ from those of DCC in more developed countries . Diarrhea is a common problem in DCC in the United States, but information on the prevalence of diarrhea or specific enteropathogens among children in DCC in tropical and developing countries is limited . METHODS: Because of preliminary data from newborns and DCC attendees in Merida, Mexico, with high rates of Salmonella infection, we conducted a 12-month longitudinal surveillance study of enteropathogens in two Merida DCC . Seventy-eight children ages 2 months to 4 years were evaluated with demographic and clinical data, and stools were cultured monthly . RESULTS: Salmonella sp . was the most common enteropathogen detected (46 of 683 specimens, 6.7%), with higher rates in children younger than 18 months (P < 0.02), but it was found in only 1 of 10 diarrhea episodes that coincided with sampling . Other common organisms identified included Giardia lamblia (21 of 683, 3.0%) and LT-producing enterotoxigenic Escherichia coli (16 of 683, 2.3%) . Salmonella was recovered from as many as 19% of children in a single month, but the large multiplicity of serotypes recovered suggested multiple sources rather than a common source outbreak . Children with Salmonella tended to have more liquid stools during the preceding 2 weeks . Salmonella was also isolated from the stool of teachers in 1 of the 2 DCC in 10 of 94 specimens (10.6%), and again multiple serotypes were represented . CONCLUSION: These data indicate the presence of multiple sources of Salmonella infection in the DCC, posing a complex situation for infection control.

Mutat Res, 2001 Dec 12, 484(1-2), 49 - 51
Prevalence of mutagens in the environment: experimental data versus simulations; Rosenkranz HS et al.; The recent availability of experimental data on the mutagenicity in Salmonella of a subset of high production volume chemicals allowed a comparison with the estimate derived from computer-based simulations . The prevalence of mutagens in the subsets was not significantly different: 20% versus 19.5% based upon experimental and simulation data, respectively . This provides support for the use of the rapid and low-cost simulation approach.

Poult Sci, 2001 Nov, 80(11), 1643 - 6
Unheated water in the first tank of a three-tank broiler scalder; Cason JA et al.; Scalding with unheated water in the first tank of a simulated three-tank scalder was tested to determine whether carcass bacteria, efficiency of feather removal, and cooked breast meat tenderness are affected as compared with carcasses scalded at the same temperature (57 C) in all tanks . This experiment was performed on 3 d using 6-wk-old broilers . On each day, eight birds per treatment were processed . During the first 40-s scalding period, one carcass was placed in approximately 24 C water . The other carcass was placed simultaneously in a scalder unit containing approximately 2,050 L of water at 57 C . Carcasses were then held out of the water for 15 s, after which both were placed for 40 s in opposite ends of the scalder containing water at 57 C . After the second scalding period, both carcasses were again removed from the water for 15 s, followed by another 40 s in the 57 C water . Total scald time was 2 min for each treatment . After picking, carcasses were rinsed with 200 mL of sterile 0.1% peptone water for 1 min . Aerobic bacteria and Escherichia coli were enumerated and incidence of salmonella was determined by standard methods . After rinsing, carcasses were eviscerated by hand and chilled for 30 min in ice slush . All carcasses were scored for the presence of feathers, and the appearance and condition of the skin were noted . Four hours postmortem, breast fillets were removed from carcasses and chilled overnight at 2 C . The next morning, breast fillets were cooked to an internal endpoint temperature of 75 to 80 C . Warner-Bratzler shear values were measured to determine tenderness . No differences were found in numbers of aerobic bacteria and E . coli, incidence of salmonellae, tenderness of cooked breast meat, or number of feathers left on carcasses.

Poult Sci, 2001 Nov, 80(11), 1543 - 8
Characterization of alkaline hydroxide-preserved whole poultry as a dry byproduct meal; Shafer DJ et al.; Studies were conducted to examine the chemical preservation of whole broiler carcasses by using aqueous alkaline hydroxide solutions . Conversion of the preserved carcasses and solutions into an acceptable poultry byproduct meal was examined . Carcasses and alkaline solutions at a 1:1 ratio were blended and freeze-dried to produce a high fat whole poultry byproduct meal . The dry meal was analyzed for nutrient composition, true metabolizable energy, and amino acid content . Viable bacteria were not recovered after inoculation of the experimental meal with Salmonella enteritidis . The meal was incorporated at 5 and 10% of chick starter diets . Chicks found the meal-containing diets acceptable . Feed consumption, water consumption, BW, and mortality were not significantly different among the dietary treatments in either of the two feeding trials . Necropsy samples revealed no pathological or histological differences attributable to consumption of the alkaline poultry byproduct and blood serum evaluation found no variation in blood chemistry . Alkaline treatment of whole broiler carcasses was an effective preservation method and acceptable as a dry poultry byproduct meal.

FEMS Microbiol Lett, 2001 Nov 13, 204(2), 287 - 91
Contribution of flagella and invasion proteins to pathogenesis of Salmonella enterica serovar enteritidis in chicks; Parker CT et al.; To explore the relative contribution that flagella and Salmonella invasion proteins make to the virulence of Salmonella enteritidis in poultry, 20-day-old chicks were challenged orally and by subcutaneous injection with wild-type strain SE-HCD, two non-flagellated mutants (fliC::Tn10 mutant and flhD::Tn10 mutant) and two Salmonella invasion protein insertion mutants (sipD and iacP) . When injected subcutaneously, wild-type SE-HCD was the only strain to cause substantial mortality and morbidity and to grow well in organs . The flhD mutant of SE-HCD was invasive when given orally, whereas wild-type SE-HCD and the fliC mutant were significantly attenuated . Salmonella invasion protein mutants were not invasive by either route . These results suggest that temporary suppression of Class I regulators of flagellin biosynthesis may aid oral infection in poultry.

Food Chem Toxicol, 2002 Jan, 40(1), 105 - 11
Evaluation of the potential effects of ingredients added to cigarettes . Part 3: in vitro genotoxicity and cytotoxicity; Roemer E et al.; Cigarette mainstream smoke from blended cigarettes with and without the addition of ingredients was assayed for its cytotoxicity and genotoxicity . In total, 333 ingredients commonly used in cigarette manufacturing were assigned to three different groups . Each group of ingredients was added at a low and a high level to the test cigarettes . The mutagenicity of the particulate phase of the resulting cigarette smoke was assayed in the Salmonella plate incorporation (Ames) assay with tester strains TA98, TA100, TA102, TA1535 and TA1537 . The cytotoxicity of the gas/vapor phase and the particulate phase was determined in the neutral red uptake assay with mouse embryo BALB/c 3T3 cells . Within the sensitivity and specificity of the test systems, the in vitro mutagenicity and cytotoxicity of the cigarette smoke were not increased by the addition of the ingredients.

Acta Paediatr Taiwan, 2001 Sep-Oct, 42(5), 297 - 300
Pediatric Salmonella enterocolitis in a teaching hospital in Taitung: A four-year analysis; Chi H et al.; In order to understand the childhood Salmonella enterocolitis in Taitung, we retrospectively collected the patients with the diagnosis of acute enterocolitis who were admitted to the pediatric wards of Taitung branch of Mackay Memorial Hospital from January 1, 1995 to December 31, 1998 . Salmonella enterocolitis accounted for 16.8% of the total cases of acute enterocolitis . The mean age of the patients was 14.6 +/- 14.1 months old . Seventy-nine patients were male and 78 patients were female . Eighty-two patients lived in the urban area and 75 patients lived in the suburbs . The mean duration from onset of illness to admission was 2.6 +/- 1.9 days . The mean duration of hospitalization was 6.6 +/- 4.8 days . The peak incidence was in August and September . The most common clinical manifestations were fever (74.5%) and blood stool (46.5%) . In 157 patients, Salmonella serogroup B was isolated from stool in 115 patients . The rate of bacteremia was 4.5% . Serogroup D accounted for 28.6% of the bacteremia . Two patients developed meningitis and one patient had osteomyelitis . Of 88 patients examined for rotavirus, 12 had positive results . There was neither bowel perforation nor mortality recorded in our study.

Int Arch Allergy Immunol, 2001 Oct, 126(2), 135 - 9
A Th1-inducing adjuvant, MPL, enhances antibody profiles in experimental animals suggesting it has the potential to improve the efficacy of allergy vaccines; Wheeler AW et al.; BACKGROUND: Monophosphoryl lipid A (MPL) is a detoxified derivative of the lipopolysaccharide (LPS) moiety of Salmonella minnesota R595, which has retained immunostimulatory activities . MPL has been administered to many subjects in clinical trials as an adjuvant component of infectious disease vaccines and is currently a component of a licensed cancer vaccine, Melacine (Corixa Inc., Schering Plough) . MPL has, in particular, been shown to promote Th1-type antigen specific responses . L-tyrosine is a depot adjuvant which is fully metabolisable and has been successfully employed in allergy vaccines for a number of years . METHODS: Mice were immunised with MPL adjuvant in conjunction with separate preparations of either ovalbumin or glutaraldehyde-modified ragweed pollen extract both coprecipitated with L-tyrosine . The specific antibody isotypes IgG1, IgG2a, IgG2b and also IgE were measured . Rats received booster injections of keyhole limpet haemocyanin (KLH) in conjunction with MPL adjuvant following priming with KLH in alum alone . KLH-specific antibody responses were measured . RESULTS: It was shown that a combination of L-tyrosine and MPL were synergistic in enhancing murine antigen specific IgG antibody responses without enhancing antigen specific IgE responses . Furthermore, this adjuvant combination promoted strong IgG2 antigen specific responses indicative of a Th1 directed response . In KLH sensitised rats, treatment with MPL was shown to prevent a secondary IgE antibody response when injected with booster injections of antigen . CONCLUSIONS: Immunisation of mice with two different antigens adsorbed to L-tyrosine induced a Th1-skewed primary response when in conjunction with MPL adjuvant which also generally enhances a specific IgG response . Incorporation of MPL adjuvant in the immunisation of rats prevented a secondary specific IgE response . These results suggest that the employment of this new adjuvant in clinical allergy vaccination formulations may result in an improved efficacy which could be utilised in various ways to improve compliance .

FEMS Microbiol Lett, 2001 Nov 27, 205(1), 25 - 9
Three molecular methods to identify Salmonella enterica serotype Typhimurium DT104: PCR fingerprinting, multiplex PCR and rapid PFGE; Ebner PD et al.; Here we report the accuracy with which three molecular techniques (PCR fingerprinting, multiplex PCR and macrorestriction profiling) distinguished Salmonella enterica Typhimurium DT104 (hereafter referred to as DT104) from other related strains of Salmonella . Each technique was tested by screening a set of 20 isolates (10 DT104, eight non-DT104 Typhimurium, one S . enterica Agona, one S . enterica Newport) and each consistently differentiated DT104 from non-DT104 isolates based on visual inspection of band patterns . The accuracy of each technique was confirmed by computer analysis . As such, these data indicate that each technique could be used to presumptively identify DT104 isolates as a precursor to phage typing.

FEBS Lett, 2001 Nov 23, 508(3), 484 - 8
Production of beta-defensin-2 by human colonic epithelial cells induced by Salmonella enteritidis flagella filament structural protein; Takahashi A et al.; We recently showed that FliC of Salmonella enteritidis increased human beta-defensin-2 (hBD-2) expression, and now describe the signaling responsible pathway . FliC increased the intracellular Ca(2+) concentration ({Ca(2+)}(in)) in Caco-2 cells . The {Ca(2+)}(in) increase induced by FliC was prevented by U73122 and heparin, but not by chelating extracellular Ca(2+) or pertussis toxin . The FliC-induced increase in hBD-2 promoter activity via nuclear factor kappaB (NF-kappaB) was also inhibited by chelation of intracellular Ca(2+) or by U73122 . We conclude that FliC increased {Ca(2+)}(in) via inositol 1,4,5-trisphosphate, which was followed by up-regulating hBD-2 mRNA expression via an NF-kappaB-dependent pathway.

Adv Exp Med Biol, 2001, 493, 247 - 54
Substance P receptor mediated macrophage responses; Marriott I et al.; Taken together, these studies demonstrate an important role for substance P receptor expression by macrophages . The results to date suggest proinflammatory signals mediated by this receptor, and it is clear that substance P can act synergistically with other factors to stimulate macrophage activity . Antagonism of substance P/substance P receptor interactions in vivo profoundly affect immunity against Salmonella . This model provides evidence that an optimal host response against this intracellular pathogen of macrophages requires signaling through the substance P receptor . The ability of interferon gamma or IL-4 to upregulate substance P receptor mRNA expression on macrophages suggests that substance P-mediated amplification loops might involve either T helper type 1 or T helper type 2 responses . Thus, depending upon the immunologic stimulus, substance P could contribute to cell mediated as well as humoral immune responses . Several important questions remain . Since the antigen processing and presenting function is an important macrophage activity, the effect of signaling through the substance P receptor on these events has not been defined . Furthermore, since macrophages are only one type of antigen presenting cell, it will be important to determine the role of substance P receptor expression in the activity of dendritic cells . We anticipate that these ongoing investigations will further define the positive contributions that substance P/substance P receptor interactions have in the initiation of immune responses.

Expert Opin Biol Ther, 2001 Mar, 1(2), 291 - 300
Use of bacteria as anticancer agents; Jain KK; Historically, bacteria were used as oncolytic agents for malignant brain tumours . Advances in bacteriology and molecular biology have widened the scope of bacterial approaches to cancer therapy and various possibilities include the use of bacteria as sensitising agents for chemotherapy, as delivery agents for anticancer drugs, and as vectors for gene therapy . Bacterial toxins can be used for tumour destruction and cancer vaccines can be based on immunotoxins of bacterial origin . The most promising approaches are the use of genetically modified bacteria for selective destruction of tumours, and bacterial gene-directed enzyme prodrug therapy . Knowledge gained from study of bacterial genomes forms an important basis of use of bacteria as anticancer agents . TAPET (Tumour Amplified Protein Expression Therapy) uses a genetically altered strain of Salmonella as a bacterial vector, or vehicle, for preferentially delivering anticancer drugs to solid tumours . Verotoxin 1 (VT1) of Escherichia coli has been used for ex vivo purging of human bone marrow of cancer cells before autologous bone marrow transplant . E . coli genes and enzymes have become part of well-known prodrug approaches to cancer in which inert prodrugs can be converted in vivo to highly active species . IL-4 fused with Pseudomonas exotoxin has been administered directly into malignant brain tumours and binds with high affinity to IL-4 receptors, which do not exist on normal brain cells, thus destroying a major part of the tumour without harming the normal brain tissue . It is in Phase I/II clinical trials in patients with glioblastoma . No ideal anticancer agent of bacterial origin that is applicable to all types of cancers has been discovered yet . The most promising approach to malignant brain tumours appears to be the use of genetically engineered bacteria that destroy the tumour selectively while sparing the normal brain tissue.

Pediatr Res, 2001 Dec, 50(6), 750 - 5
Neonatal endotoxin exposure influences HPA responsivity and impairs tumor immunity in Fischer 344 rats in adulthood; Hodgson DM et al.; Recent research in rodents has demonstrated that exposure to bacterial endotoxin during the neonatal period alters the development of the hypothalamic-pituitary-adrenal axis resulting in hypersecretion of corticosterone after stress-exposure in adulthood . Given the known interactions between glucocorticoids and the immune system it was hypothesized that such alterations may impact on immune outcomes . Fischer 344 rats were treated with endotoxin (50 microg/kg Salmonella enteritidis, i.p.) or the vehicle on postpartum d 1, 3, 5, and 7 . In adulthood, animals were subjected to chronic stress (6 x 10 h/d restraint stress), and the effect on resistance to tumor colonization (experiment 1) and natural killer cell activity (experiment 2) was assessed . Experiment 3 assessed corticosterone responses to acute stress in adulthood after neonatal endotoxin or saline treatment . Neonatal endotoxin exposure resulted in a 2-fold increase in tumor colonization (p < 0.001) and a significant impairment in the activity of natural killer cells (p < 0.01), cells critically involved in the surveillance and eradication of tumor cells . Neonatal endotoxin exposure also resulted in a significant decrease in gain weight that persisted into adulthood (p < 0.05), and potentiation of corticosterone responses to acute stress in adulthood (p < 0.05) . We conclude that neonatal endotoxin exposure produces long-term changes in the hypothalamic-pituitary-adrenal axis, and has significant long-term effects on immune function, specifically in terms of resistance to tumor colonization in adulthood.

J Food Prot, 2001 Nov, 64(11), 1832 - 5
Prevalence of Salmonella serovars in chickens in Turkey; Carli KT et al.; In this study, 151 (18.6%) of 814 ceca obtained during in-line processing of 28 broiler (Hybro G, Avian, Arbor acres, and Cobb breeds) and 5 layer (Ross, Tetra SL, Isa Brown, and Brown Nick breeds) flocks in Turkey were found to be contaminated with four different Salmonella serovars . Only Salmonella enterica subsp . enterica Serovar Enteritidis (Salmonella Enteritidis) was recovered from layer birds, whereas Salmonella Enteritidis (81.5%) . Salmonella Agona (7.6%), Salmonella Thompson (10.1%), and Salmonella Sarajane (0.8%) were isolated from broiler birds . Isolations of Salmonella Agona and Salmonella Thompson from poultry are reported for the first time in Turkey . The isolation of Salmonella Sarajane from chickens is the first report in the world . The standard method of National Poultry Improvement Plan, U.S . Department of Agriculture, was used to detect Salmonella from chicken cecal samples . Primary and delayed secondary enrichments (PE and DSE) were done in tetrathionate-Hajna broth (TTHB) . Two different agar media, xylose lysine tergitol 4 (XLT4) and brilliant green with novobiocin (BGN) were used to observe, and compared for their isolation and selective differentiation of, Salmonella-suspected colonies . Isolated salmonellae were then biotyped and serotyped . Ninety-one and 151 salmonellae were isolated with XLT4 agar after PE and DSE, respectively . From the same samples, BGN agar was able to detect only 50 and 131 Salmonella after PE and DSE, respectively . The isolation rate with XLT4 was 11.2% (P < 0.01) with PE, and this rate increased to 18.6% after DSE . Also, the PE isolation rate (11.2%) with XLT4 agar was significantly higher (P < 0.01) than PE with BGN agar (6.1%) . Salmonella was isolated from 39.3% (11 of 28) of the broiler flocks and from 60.0% (3 of 5) of the layers . The detection sensitivity of the isolation method was determined as 1 CFU g(-1) experimentally . These data demonstrate the presence of Salmonella Enteritidis, Salmonella Thompson, Salmonella Agona, and Salmonella Sarajane in chicken flocks in Turkey.

J Food Prot, 2001 Nov, 64(11), 1828 - 31
Growth rates of Salmonella and Escherichia coli O157:H7 in irradiated beef; Dickson JS et al.; Ground beef was irradiated to 0, 2, or 4 kGy and then inoculated with a mixed culture of four serotypes of salmonellae or five strains of Escherichia coli O157:H7 . The ground beef was stored at either 15 or 25 degrees C, and the growth of the inoculated bacteria was monitored over time . Growth parameters were determined for both the salmonellae and the E . coli O157:H7 using the Gompertz equation . There was no significant difference in lag phase duration or generation time, irrespective of the dose to which the ground beef had previously been exposed . Furthermore, the lag phase durations and generation times determined in this study did not differ significantly from previously published values . This suggests that, although irradiation eliminates a significant portion of the spoilage microflora in ground beef, the absence of this microflora provides no competitive advantage to the growth of salmonellae or E . coli O157:H7 in ground beef.

J Food Prot, 2001 Nov, 64(11), 1761 - 7
Growth and recovery of selected gram-negative bacteria in reconditioned wastewater; Rajkowski KT et al.; Previous reports indicate that Escherichia coli O157:H7, Salmonella spp., and Vibrio cholerae can grow in nutrient-limited, reconditioned wastewater over the temperature range of 4 to 46 degrees C when the biological oxygen demand of this water is <2, while its coliform growth response (CGR) is >2 . In the current study, we investigated the growth response of Vibrio parahaemolyticus, Shigella spp., Vibrio vulnificus, and Pseudomonas aeruginosa in water samples with a CGR of >2 over the temperature range of 4 to 50 degrees C . Both the nonselective media, tryptic soy agar, and the selective media used to identify the pathogen were used for their recovery . The selective media were thiosulfate-citrate-bile-sucrose (TCBS), MacConkey agar (MAC), and Pseudomonas isolation agar (PIA) for the Vibrio, Shigella, and Pseudomonas spp., respectively . V . parahaemolyticus numbers declined rapidly after surviving for 6 days under the nutrient-limiting growth conditions . Shigella spp . did not grow but survived for >28 days at 4 to 25 degrees C . V . vulnificus grew over the narrow temperature range of 12 to 21 degrees C and survived for >21 days at the higher and lower temperature ranges . P . aeruginosa survived and grew during the 14-day test period at 13 to 35 degrees C . Recovery on the nonselective agar gave statistically (P > 0.05) higher numbers than the respective selective media commonly used for these pathogens . These results indicate that caution should be used in attempting direct recoveries using selective media of the four gram-negative bacteria species used in this study from the nutrient-limited water environment.

J Food Prot, 2001 Nov, 64(11), 1744 - 50
Combination of immunomagnetic separation and polymerase chain reaction for the simultaneous detection of Listeria monocytogenes and Salmonella spp . in food samples; Hsih HY et al.; A method that combined the immunomagnetic separation (IMS) technique and the multiplex polymerase chain reaction (PCR) method (i.e., the IMS-mPCR method) was developed for simultaneous detection of Listreria monocytogenes and Salmonella spp . in food samples . When only the multiplex PCR method was used, it was found that if cell numbers of each of the two target organisms (L . monocytogenes and Salmonella spp.) were above the detection limit, but differed by more than 2 logs-e.g., n x 10(7) to n x 10(4) or n x 10(6) to n x 10(3)--the organism presenting the lower numbers might go undetected . Following the enrichment step with universal preenrichment (UP) broth, if an IMS method using equal quantities of anti-Listeria and anti-Salmonella immunomagnetic beads was performed prior to PCR, both pathogens could be detected unambiguously . Such results could be obtained for target organisms in food samples, such as milk, dairy, and meat products, if similar enrichment and IMS steps were performed prior to PCR.

J Food Prot, 2001 Nov, 64(11), 1690 - 7
Sources and movement of Salmonella through integrated poultry operations: a multistate epidemiological investigation; Bailey JS et al.; The prevalence of Salmonella from numerous sources in 32 integrated broiler operations of high- and low-performing broiler houses was characterized from four states across four seasons . Previous studies of Salmonella in broilers have been limited in scope, offering only a snapshot of pathogen prevalence as seen on a small number of individual farms . Twenty-six different sample types were collected from the hatchery to the end of processing, and Salmonella was found in all sample types . A total of 10,740 samples were analyzed for Salmonella, and 973 (9.1%) of these samples, including 49 of 798 (6.1%) carcass rinse samples, were Salmonella positive . Hatchery transport pads (389 of 765, 50.8%), flies (28 of 150, 18.7%), drag swabs (57 of 402, 14.2%), and boot swabs (20 of 167, 12%) were samples from which Salmonella was most frequently isolated . Thirty-six different serotypes were identified, and the most frequently encountered serotypes were Salmonella Senftenberg, Salmonella Thompson, and Salmonella Montevideo . Determining critical contaminating sources and following the movement of Salmonella through integrated poultry operations will help researchers and the industry develop practical intervention strategies.

J Food Prot, 2001 Nov, 64(11), 1679 - 89
Validation of apple cider pasteurization treatments against Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes; Mak PP et al.; Time and temperature pasteurization conditions common in the Wisconsin cider industry were validated using a six-strain cocktail of Escherichia coli O157:H7 and acid-adapted E . coli O157:H7 in pH- and degrees Brix-adjusted apple cider . Strains employed were linked to outbreaks (ATCC 43894 and 43895, C7927, and USDA-FSIS-380-94) or strains engineered to contain the gene for green fluorescent protein (pGFP ATCC 43894 and pGFP ATCC 43889) for differential enumeration . Survival of Salmonella spp . (CDC 0778 . CDC F2833, and CDC H0662) and Listeria monocytogenes (H0222, F8027, and F8369) was also evaluated . Inoculated cider of pH 3.3 or 4.1 and 11 or 14 degrees Brix was heated under conditions ranging from 60 degrees C for 14 s to 71.1 degrees C for 14 s . A 5-log reduction of nonadapted and acid-adapted E . coli O157:H7 was obtained at 68.1 degrees C for 14 s . Lower temperatures, or less time at 68.1 degrees C, did not ensure a 5-log reduction in E . coli O157:H7 . A 5-log reduction was obtained at 65.6 degrees C for 14 s for Salmonella spp . L . monocytogenes survived 68.1 degrees C for 14 s, but survivors died in cider within 24 h at 4 degrees C . Laboratory results were validated with a surrogate E coli using a bench-top plate heat-exchange pasteurizer . Results were further validated using fresh unpasteurized commercial ciders . Consumer acceptance of cider pasteurized at 68.1 degrees C for 14 s (Wisconsin recommendations) and at 71.1 degrees C for 6 s (New York recommendations) was not significantly different . Hence, we conclude that 68.1 degrees C for 14 s is a validated treatment for ensuring adequate destruction of E . coli O157:H7, Salmonella spp., and L . monocytogenes in apple cider.

J Vet Diagn Invest, 2001 Nov, 13(6), 483 - 8
Serological distinction of bovine Salmonella carriers from vaccinated and acutely infected cows; House JK et al.; Identification of Salmonella carriers using lipopolysaccharide (LPS) ELISA serology in a Salmonella-infected herd requires distinction of chronically infected cattle from convalescent and vaccinated cows . Cows responding to Salmonella infection and vaccination produce titers to Salmonella LPS that overlap with the lower titers of some Salmonella carriers . The objective of this study was to determine if the LPS antigen specificity of the bovine humoral immune response to Salmonella LPS antigens differs following vaccination and acute and chronic Salmonella infection . The study focused on the nondiscriminatory area of Salmonella ELISA serology, specifically, peak-titered sera from Salmonella bacterin-vaccinated and experimentally infected cows and low-titered sera from Salmonella carriers . The LPS serogroup specificity of the IgG1 and IgG2 response following acute and chronic Salmonella serotype Dublin infection and Salmonella bacterin vaccination was evaluated using 5 Salmonella serogroup (B, D, E1, C3, and C1) LPS ELISA assays . IgG, titers of carriers, vaccinated, and acutely infected cows were predominantly O antigen specific . Similarly, the IgG2 titers of acutely infected cows were also O antigen specific . In contrast, Salmonella carriers produced an IgG2 response to each of the heterologous LPS antigens (B, E1, C3, and C1) examined . The results of this study indicate that the bovine IgG1 isotype response to Salmonella LPS is serogroup specific . Conversely, production of IgG2 antibodies to core Salmonella LPS antigens shared across Salmonella serogroups is a feature of chronic Salmonella infections.

Mol Microbiol, 2001 Nov, 42(3), 705 - 15
Cellular location and temperature-dependent assembly of IncHI1 plasmid R27-encoded TrhC-associated conjugative transfer protein complexes; Gilmour MW et al.; Conjugal transfer of IncHI plasmid DNA between Gram-negative bacteria is temperature sensitive, as mating is optimal between 22 degrees C and 30 degrees C but is inhibited at 37 degrees C . R27, isolated from Salmonella enterica serovar Typhi, is an IncHI1 plasmid of 180 kbp that has been sequenced completely . The gene encoding green fluorescent protein (GFP) was inserted into R27 in frame with trhC . TrhC is a mating pair formation (Mpf) protein that is essential for plasmid transfer and H-pilus production . Fluorescence microscopy allowed visualization of the TrhC-GFP fusion protein, and Escherichia coli cells were examined for the subcellular localization and temperature-dependent production of TrhC-GFP . At 27 degrees C, TrhC-GFP was found at the periphery of cells as discrete foci, indicating an association of TrhC within protein complexes in the bacterial cell membrane, whereas at 37 degrees C, little fluorescence was detected . These foci probably represent the intracellular position of protein complexes involved in conjugative transfer, as the formation of foci was dependent upon the presence of other Mpf proteins . During temperature shift experiments from 37 degrees C to 27 degrees C, a long lag period was required for generation of GFP foci . Conversely, during short shifts from 27 degrees C to 37 degrees C, the GFP foci remained stable . These results suggest that the expression of transfer genes in the Tra2 region of R27 is temperature dependent . Subcellular localization of TrhC was verified by cellular fractionation . Expression patterns of TrhC-GFP were confirmed with immunoblot analysis and reverse transcriptase-polymerase chain reaction (RT-PCR) . These results allow us to propose mechanisms to explain the temperature-sensitive transfer of R27.

J Appl Microbiol, 2001 Nov, 91(5), 871 - 7
Low molecular weight milk whey components protect Salmonella senftenberg 775W against heat by a mechanism involving divalent cations; Manas P et al.; AIMS: To investigate which components of milk increase the heat resistance of Salmonella senftenberg 775W, and to explore the mechanisms that could be involved in this protective effect . METHODS AND RESULTS: The heat resistance of Salm . senftenberg was determined in a specially designed resistometer in several heating media . The molecules responsible for the thermal protective effect of milk were in the protein fraction, even in the < 3000 Da ultrafiltrate . The protective effect was lost when whey was demineralized . The former protective effect was restored when calcium or magnesium was added . Milk components protected cell envelopes of Salm . senftenberg from heat damage . CONCLUSIONS: The protein fraction and divalent cations were responsible for the protective effect of milk . The whole protective effect on Salm . senftenberg was not the result of the addition of the protective effect of each component, but the result of a synergistic effect of some of them interacting . SIGNIFICANCE AND IMPACT OF THE STUDY: This work could be useful for improving food preservation and hygiene treatments . It also contributes to our knowledge of microbial physiology.

Anal Chem, 2001 Nov 1, 73(21), 5302 - 9
Self-assembled monolayers as the coating in a quartz piezoelectric crystal immunosensor to detect Salmonella in aqueous solution; Fung YS et al.; A new procedure based on the self-assembled monolayers (SAM) of alkanethiols was developed to immobilize antibodies onto gold electrodes of a quartz crystal microbalance (QCM) for detecting Salmonella paratyphi A . The procedure includes (1) chemisorption of 3-mercaptopropionic acid (MPA) at electrode surfaces to produce a carboxylic acid terminated monolayer, (2) activation by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydrosuccinimide (NHS) to generate a stable acyl amino ester intermediate, and (3) condensation of antibodies after aminolysis of the NHS adduct . Activation by two coupling agents (EDC and NHS) was shown to enhance the stability of the coating and facilitate the formation of a suitable intermediate to condense antibodies reproducibly and densely at the SAM, leading to high sensitivity and good precision of the developed immunosensor . With 50 min incubation under continuous monitoring, working ranges from 10(2) to 10(5) cells/mL with repeatability < 10% RSD were obtained . On the basis of S/N = 3, the detection limit was 1.7 x 10(2) cells/mL The MO2 piezoimmunosensor developed was specific to differentiate S . paratyphi A against Escherichia coli and other serogroups of Salmonella that are commonly present together.

New Microbiol, 2001 Oct, 24(4), 371 - 7
Clonal relations among Salmonella enteritidis phage type 3 outbreak isolates traced by DNA fingerprinting; Muresu E et al.; Isolates of Salmonella enteritidis PT3, a rare phage type, were recovered from patients and strains were isolated from an outbreak of gastroenteritis that occurred during the summer of 1997 in North-East Sardinia, Italy . To investigate possible clonal involvement in the outbreak and to evaluate the capacity to discriminate among S . enteritidis PT3 strains, a number of molecular typing methods including ribotyping with a mixture of PstI and SphI (PS-ribotyping), PFGE with endonuclease XbaI and RAPD typing with four arbitrary primers was used . The typical XbaI endonuclease generated PFGE pattern also explained the prevalence of highly clonal S . enteritidis PT3 strains in the outbreak and adjacent areas . RAPD fingerprinting with primers OPA 4, OPB 15, OPB17 and P1254 exhibited a single but unique RAPD profile among the outbreak strains from various sources that differed significantly from control strains . The results of this study showed that when an appropriately chosen set of primers is employed, RAPD fingerprinting can be used as an alternative, rapid, highly reproducible technique for tracing the clonal relations of S . enteritidis PT3, and can be more discriminatory than PFGE . Furthermore, this study revealed the possibility of PT3 causing outbreak.

Proc Natl Acad Sci U S A, 2001 Nov 20, 98(24), 13722 - 7
Flagellin stimulation of intestinal epithelial cells triggers CCL20-mediated migration of dendritic cells; Sierro F et al.; Enteropathogenic bacteria elicit mucosal innate and adaptive immune responses . We investigated whether gut epithelial cells played a role in triggering an adaptive immune response by recruiting dendritic cells (DCs) . Immature DCs are selectively attracted by the CCL20 chemokine . The expression of the CCL20 gene in human intestinal epithelial cell lines was up-regulated by pathogenic bacteria, including Salmonella species, but not by indigenous bacteria of the intestinal flora . The Salmonella machinery for epithelial cell invasion was not required for CCL20 gene activation . Flagellin but not the lipopolysaccharide was found to be the Salmonella factor responsible for stimulation of epithelial CCL20 production . CCL20 in turn triggered a specific migration of immature DCs . Our data show that crosstalk between bacterial flagellin and epithelial cells is essential for the recruitment of DCs, a mechanism that could be instrumental to initiate adaptive immune responses in the gut.

J Bacteriol, 2001 Dec, 183(24), 7053 - 7
The PPP-family protein phosphatases PrpA and PrpB of Salmonella enterica serovar Typhimurium possess distinct biochemical properties; Shi L et al.; Salmonella enterica serovar Typhimurium requires Mn(2+), but only a few Mn(2+)-dependent enzymes have been identified from bacteria . To characterize Mn(2+)-dependent enzymes from serovar Typhimurium, two putative PPP-family protein phosphatase genes were cloned from serovar Typhimurium and named prpA and prpB . Their DNA-derived amino acid sequences showed 61% identity to the corresponding Escherichia coli proteins and 41% identity to each other . Each phosphatase was expressed in E . coli and purified to near electrophoretic homogeneity . Both PrpA and PrpB absolutely required a divalent metal for activity . As with other phosphatases of this class, Mn(2+) had the highest affinity and stimulated the greatest activity . The apparent K(a) of PrpA for Mn(2+) of 65 microM was comparable to that for other bacterial phosphatases, but PrpB had a much higher affinity for Mn(2+) (1.3 microM) . The pH optima were pH 6.5 for PrpA and pH 8 for PrpB, while the optimal temperatures were 45 to 55 degrees C for PrpA and 30 to 37 degrees C for PrpB . Each phosphatase could hydrolyze phosphorylated serine, threonine, or tyrosine residues, but their relative specific activities varied with the specific substrate tested . These differences suggest that each phosphatase is used by serovar Typhimurium under different growth or environmental conditions such as temperature or acidity.

Nucleic Acids Res . 2001 Nov 15;29(22):E111.
Detection of simple mutations and polymorphisms in large genomic regions; Sokurenko EV et al.; We have developed a novel technology that makes it possible to detect simple nucleotide polymorphisms directly within a sample of total genomic DNA . It allows, in a single Southern blot experiment, the determination of sequence identity of genomic regions with a combined length of hundreds of kilobases . This technology does not require PCR amplification of the target DNA regions, but exploits preparative size-fractionation of restriction-digested genomic DNA and a newly discovered property of the mismatch-specific endonuclease CEL I to cleave heteroduplex DNA with a very high specificity and sensitivity . We have used this technique to detect various simple mutations directly in the genomic DNA of isogenic pairs of recombinant Pseudomonas aeruginosa, Escherichia coli and Salmonella isolates . Also, by using a cosmid DNA library and genomic fractions as hybridization probes, we have compared total genomic DNA of two clinical P.aeruginosa clones isolated from the same patient, but exhibiting divergent phenotypes . The mutation scan correctly detected a GA insertion in the quorum-sensing regulator gene rhlR and, in addition, identified a novel intragenomic polymorphism in rrn operons, indicating very high stability of the bacterial genomes under natural non-mutator conditions.

Kansenshogaku Zasshi, 2001 Oct, 75(10), 837 - 45
{Serovar-distribution, drug-resistance, and DNA analysis of Salmonella strains isolated from sporadic diarrhea cases or healthy cases in Tama, Tokyo (1991-2000)}; Kato R et al.; Serovar-distribution and drug-resistance of a total of 421 Salmonella strains, which were 98 stains from sporadic diarrhea cases and 323 strains from healthy cases between 1991 and 2000 in Tama, Tokyo were investigated . In serological typing tests, the strains tested were classified into 26 different kinds of serovar in diarrhea cases, 58 in food handlers, and 25 in individuals for health care . Salmonella serovar Enteritidis (S . Enteritidis) was the most predominant serovar in three cases . Following, S . Typhimurium and S . Infantis in diarrhea cases, S . Hadar, S . Montevideo and S . Thompson in food handlers, or S . Typhimurium, S . Lichfield and S . Oranienburg in healthy individuals were frequent . The drug-resistance test using 9 drugs (CP, TC, SM, KM, ABPC, SXT, NA, FOM, and NFLX) showed that 57.1% of the strains from diarrhea cases and 36.8% from the healthy cases were resistant to one or the other of the drugs examined . Drug-resistance patterns of those showed 13 types in diarrhea cases and 25 types in healthy cases . Out of them, strains which showed a predominant and common pattern in both cases were SM resistant-S . Enteritidis and CP.TC.SM.ABPC resistant-S . Typhimurium . In addition, the latter strains were also resistant to sulfiso-xzole (SU) . In DNA analysis by RAPD method of their strains, common DNA finger-prints were observed in both cases through out the investigation period.

Rheumatology (Oxford), 2001 Nov, 40(11), 1285 - 92
Reactive haemophagocytic syndrome in children with inflammatory disorders . A retrospective study of 24 patients; Stephan JL et al.; BACKGROUND: The reactive haemophagocytic syndrome (RHS) is a little-known life-threatening complication of rheumatic diseases in children . It reflects the extreme vulnerability of these patients, especially those with systemic-onset juvenile chronic arthritis (JCA) . This immunohaematological process may be triggered by events such as herpes virus infection and non-steroidal anti-inflammatory drug therapy . Treatment has not been standardized . METHODS: We characterized this unusual disorder and determined its incidence by carrying out a retrospective study of patients identified over a 10-yr period in French paediatric units . RESULTS: Twenty-four cases (nine males, 15 females) were studied . Eighteen had typical systemic-onset JCA, two had polyarthritis, two had lupus and two had unclassifiable disorders . Clinical features at diagnosis included high spiking fever (24 patients), enlargement of the liver and spleen (14), haemorrhagic diathesis (six), pulmonary involvement (12) and neurological abnormalities (coma or seizures) (12) . RHS was the first manifestation of systemic disease in three cases . Admission to intensive care was required in ten cases . Hypofibrinogenaemia, elevated liver enzymes and hypertriglyceridaemia were found consistently . Phagocytic histiocytes were found in 14 of 17 bone marrow smears . RHS was presumed to have been precipitated by infection in 11 cases (four Epstein-Barr virus, three varicella-zoster virus, one parvovirus B19, one Coxsackie virus, one Salmonella, one Pneumocystis carinii) and by the introduction of medication in three cases (Salazopyrin plus methotrexate; morniflumate; aspirin) . Macrophage activation was indicated by high levels of monokines in the serum of two patients . Twenty patients had only one episode, three had an early relapse and one patient had two relapses . The treatment regimen was tailored to each child as the clinical course was variable . There was no response to intravenous immunoglobulins, which were used in four cases . Intravenous steroids at doses ranging from conventional to pulse methylprednisolone induced remission in 15 of 21 episodes when used alone as the first-line treatment . Cyclosporin A was consistently and rapidly effective, both when used as second-line therapy in all seven of the episodes in which steroids failed and in all five patients who received it as their first-line treatment . This supports a central role of T lymphocytes in the haemophagocytic syndrome . Two patients died . One patient with lupus died of congestive fulminant heart failure after 4 days, despite treatment with intravenous steroids and immunoglobulins, and one patient with systemic-onset JCA died from multiorgan failure despite aggressive therapy with pulsed steroids and etoposide . CONCLUSIONS: RHS may be a more common complication of systemic disease in childhood than previously thought . This life-threatening complication should be diagnosed promptly, as it calls for the immediate withdrawal of potentially triggering medications, anti-infective therapy when relevant, and urgent immunosuppressive treatment, measures that are very often effective . Cyclosporin A may be the drug of choice.

Antimicrob Agents Chemother, 2001 Dec, 45(12), 3647 - 50
Identification and expression of cephamycinase bla(CMY) genes in Escherichia coli and Salmonella isolates from food animals and ground meat; Zhao S et al.; Twenty-one Salmonella and 54 Escherichia coli isolates, recovered from food animals and retail ground meats, that exhibited decreased susceptibilities to ceftiofur and ceftriaxone were shown to possess a bla(CMY) gene . The bla(CMY-4) gene was identified in an E . coli isolate recovered from retail chicken and was further shown to be responsible for resistance to cephalothin, ampicillin, and amoxicillin-clavulanic acid and elevated MICs of ceftriaxone, cefoxitin, and ceftiofur.

Semin Immunol, 2001 Dec, 13(6), 381 - 90
Phagocytosis of bacterial pathogens: implications in the host response; Sansonetti P; Phagocytosis of bacterial pathogens is at the heart of the pathogenesis of infections . Pathogens have evolved a large array of strategies to escape the deleterious effect of phagocytosis by professional phagocytes among which avoiding phagocytosis, killing the phagocytes or surviving inside them are the most 'popular' solutions . Bacterial pathogens are also using induction of phagocytic entry into non-professional phagocytic cells, such as epithelial cells, as a strategy of survival and multiplication . We have taken enteroinvasive micro-organisms such as Yersinia, Shigella and Salmonella as a paradigm of the significance of phagocytosis/antiphagocytosis in the development of an infection and on the elicitation of the host response .

Anim Health Res Rev, 2001 Jun, 2(1), 31 - 6
Porcine enteric spirochete infections in the UK: surveillance data and preliminary investigation of atypical isolates; Thomson JR et al.; Investigations into the possible causes of colitis and typhlocolitis were carried out on 98 pig units in the United Kingdom between 1997 and 1999 . Brachyspira pilosicoli was identified most commonly, occurring as the suggested primary agent in 18% of the outbreaks but forming part of mixed infections in another 24% of outbreaks . The equivalent figures for other bacterial pathogens were: B . hyodysenteriae, 13% and 16%; Lawsonia intracellularis, 10% and 15%: Salmonella species, 6% and 12%; and Yersinia species, 4% and 10% . Unclassified Brachyspira species of unknown pathogenicity were identified in 12% of outbreaks . The 24 unclassified isolates divided into three groups on the basis of their phenotypic characteristics . In addition, there were 50 atypical Brachyspira species isolates that showed differences between their phenotypic characteristics and genetic identity based on sequence analysis of a section of the 23S rDNA gene . Four representative atypical isolates were found to be pathogenic as a result of an experimental oral challenge study in pigs.

J Vet Med B Infect Dis Vet Public Health, 2001 Oct, 48(8), 569 - 81
Why is anti-microbial resistance a veterinary problem as well?
Mateu E, Martin M.
Resistance to anti-microbial agents has become one of the main issues in public health strategies world-wide . Much attention has been paid to the emergence of pathogenic micro-organisms such as enterococci or Salmonella that have developed resistance mechanisms that render them almost untreatable with current antibiotics . One of the alleged reasons for such an emergence is the non-medical use of antibiotics, especially in animals . However, only recently have veterinary forums and journals begun to discuss this topic . On the other hand, anti-microbial resistance has also become a problem in veterinary medicine and the number of reports indicating high rates of resistance among animal-originated micro-organisms is considerable . The present review deals with the mechanisms of resistance known for antibiotics in common veterinary use, the problem of anti-microbial resistance in veterinary medicine and the links between the use of antibiotics in animals and the emergence of anti-microbial resistance in humans.

Anim Health Res Rev, 2000 Jun, 1(1), 47 - 65
Vaccines against the avian enteropathogens Eimeria, Cryptosporidium and Salmonella; Lillehoj EP et al.; The worldwide poultry industry provides a substantial proportion of the nutritional requirement of the human population . To keep pace with the increasing demand for the high-quality, low-cost protein source that poultry provides, intensive rearing practices have been developed within the past few decades . For example, chickens are housed routinely in crowded environments under adverse conditions, and genetic strains have been selected for rapid growth, high protein-to-fat content and superior egg-laying characteristics . A major negative consequence of these practices has been an increase in the incidence of diseases . Enteric diseases in particular have emerged as a major problem threatening the future viability of the poultry industry . A variety of methods have been used to combat avian diseases in the commercial setting, including improved farm management practices, the use of antibiotic drugs, the selection of disease-resistant strains of chickens, and the manipulation of the chicken's immune system . In the latter category, the development of vaccines against the major avian diseases has become a priority in the poultry industry . This review will highlight recent progress in vaccine development against three major avian enteric pathogens: Eimeria, Cryptosporidium and Salmonella.

Infect Immun, 2001 Dec, 69(12), 7950 - 4
Salmonella DNA adenine methylase mutants elicit protective immune responses to homologous and heterologous serovars in chickens; Dueger EL et al.; Salmonella DNA adenine methylase (Dam) mutants that lack or overproduce Dam are highly attenuated for virulence in mice and confer protection against murine typhoid fever . To determine whether vaccines based on Dam are efficacious in poultry, a Salmonella Dam(-) vaccine was evaluated in the protection of chicken broilers against oral challenge with homologous and heterologous Salmonella serovars . A Salmonella enterica serovar Typhimurium Dam(-) vaccine strain was attenuated for virulence in day-of-hatch chicks more than 100,000-fold . Vaccination of chicks elicited cross-protective immune responses, as evidenced by reduced colonization (10- to 10,000-fold) of the gastrointestinal tract (ileum, cecum, and feces) and visceral organs (bursa and spleen) after challenge with homologous (Typhimurium F98) and heterologous (Enteritidis 4973 and S . enterica O6,14,24: e,h-monophasic) Salmonella serovars that are implicated in Salmonella infection of poultry . The protection conferred was observed for the organ or the maximum CFU/tissue/bird as a unit of analysis, suggesting that Dam mutant strains may serve as the basis for the development of efficacious poultry vaccines for the containment of Salmonella.

Infect Immun, 2001 Dec, 69(12), 7915 - 21
Infection of synovial fibroblasts in culture by Yersinia enterocolitica and Salmonella enterica serovar Enteritidis: ultrastructural investigation with respect to the pathogenesis of reactive arthritis; Meyer-Bahlburg A et al.; Synovial fibroblasts were infected with Yersinia enterocolitica or Salmonella enterica serovar Enteritidis and analyzed by electron microscopy and fluorescence in situ hybridization . Intracellular bacterial replication was followed by degradation leading to "ghosts" possessing lipopolysaccharides but not DNA . However, single bacteria survived for more than 2 weeks . Therefore, transient intra-articular infection might be the missing link between initial intestinal infection and late synovial inflammation in the pathogenesis of reactive arthritis.

Infect Immun, 2001 Dec, 69(12), 7873 - 9
Salmonella enterica serovar Pullorum persists in splenic macrophages and in the reproductive tract during persistent, disease-free carriage in chickens; Wigley P et al.; Salmonella enterica serovar Pullorum is worldwide a poultry pathogen of considerable economic importance, particularly in those countries with a developing poultry industry . In addition to the characteristic high mortality rates among young chicks, one of the features of Salmonella serovar Pullorum infection is that it persists for long periods in convalescent chicks in the absence of clinical disease . This can lead to colonization of the reproductive tract of chickens and at sexual maturity can result in infected progeny through transovarian transmission to eggs . The sites of Salmonella serovar Pullorum persistence in convalescent birds are not known, and the mechanisms of persistence are not understood . Here we show that Salmonella serovar Pullorum can persist in both the spleen and the reproductive tract for over 40 weeks following experimental infection in chickens . During the period of sexual maturity, Salmonella serovar Pullorum colonized both the ovary and the oviduct of hens and led to 6% of laid eggs being infected by Salmonella serovar Pullorum . The colonization of several different sites of the reproductive tract suggests that Salmonella serovar Pullorum may employ more than one mechanism of egg infection . Persistence occurred despite a strong humoral response, suggesting an intracellular site of infection . By use of a Salmonella serovar Pullorum strain containing a plasmid stably expressing green fluorescent protein, we demonstrated that the main site of carriage in the spleen is within macrophages . This raises interesting questions about the biology of Salmonella serovar Pullorum, including why there is an increase in bacterial numbers when birds become sexually mature and in particular how Salmonella serovar Pullorum avoids clearance by macrophages and whether it modulates the immune system in other ways.

Infect Immun, 2001 Dec, 69(12), 7610 - 5
DNA adenine methylase is essential for viability and plays a role in the pathogenesis of Yersinia pseudotuberculosis and Vibrio cholerae; Julio SM et al.; Salmonella strains that lack or overproduce DNA adenine methylase (Dam) elicit a protective immune response to different Salmonella species . To generate vaccines against other bacterial pathogens, the dam genes of Yersinia pseudotuberculosis and Vibrio cholerae were disrupted but found to be essential for viability . Overproduction of Dam significantly attenuated the virulence of these two pathogens, leading to, in Yersinia, the ectopic secretion of virulence proteins (Yersinia outer proteins) and a fully protective immune response in vaccinated hosts . Dysregulation of Dam activity may provide a means for the development of vaccines against varied bacterial pathogens.

Infect Immun, 2001 Dec, 69(12), 7493 - 500
Regulated antigen expression in live recombinant Salmonella enterica serovar Typhimurium strongly affects colonization capabilities and specific CD4(+)-T-cell responses; Bumann D; Regulated antigen expression can influence the immunogenicity of live recombinant Salmonella vaccines, but a rational optimization has remained difficult since important aspects of this effect are incompletely understood . Here, attenuated Salmonella enterica serovar Typhimurium SL3261 strains expressing the model antigen GFP_OVA were used to quantify in vivo antigen levels by flow cytometry and to simultaneously follow the crucial early steps of antigen-specific T-cell responses in mice that are transgenic for a T-cell receptor recognizing ovalbumin . Among seven tested promoters, P(pagC) has the highest activity in murine tissues combined with low in vitro expression, whereas P(tac) has a comparable in vivo and a very high in vitro activity . Both SL3261 (pP(pagC)GFP_OVA) and SL3261 (pP(tac)GFP_OVA) cells can induce potent ovalbumin-specific cellular immune responses following oral administration, but doses almost 1,000-fold lower are sufficient for the in vivo-inducible construct SL3261 (pP(pagC)GFP_OVA) compared to SL3261 (pP(tac)GFP_OVA) . This efficacy difference is largely explained by impaired early colonization capabilities of SL3261 (pP(tac)GFP_OVA) cells . Based on the findings of this study, appropriate in vivo expression levels for any given antigen can be rationally selected from the increasing set of promoters with defined properties . This will allow the improvement of recombinant Salmonella vaccines against a wide range of pathogens.

Infect Immun, 2001 Dec, 69(12), 7413 - 8
Novel Salmonella enterica serovar Typhimurium protein that is indispensable for virulence and intracellular replication; van der Straaten T et al.; Upon contact with host cells, the intracellular pathogen Salmonella enterica serovar Typhimurium promotes its uptake, targeting, and survival in intracellular niches . In this process, the bacterium evades the microbicidal effector mechanisms of the macrophage, including oxygen intermediates . This study reports the phenotypic and genotypic characterization of an S . enterica serovar Typhimurium mutant that is hypersusceptible to superoxide . The susceptible phenotype is due to a MudJ insertion-inactivation of a previously undescribed Salmonella gene designated sspJ that is located between 54.4 and 64 min of the Salmonella chromosome and encodes a 392-amino-acid protein . In vivo, upon intraperitoneal injection of 10(4) to 10(7) bacteria in C3H/HeN and 10(1) to 10(4) bacteria in BALB/c mice, the mutant strain was less virulent than the wild type . Consistent with this finding, during the first hour after ingestion by macrophage-like J774 and RAW264.7 cells in vitro, the intracellular killing of the strain carrying sspJ::MudJ is enhanced fivefold over that of wild-type microorganisms . Wild-type salmonellae displayed significant intracellular replication during the first 24 h after uptake, but sspJ::MudJ mutants failed to do so . This phenotype could be restored to that of the wild type by sspJ complementation . The SspJ protein is found in the cytoplasmic membrane and periplasmic space . Amino acid sequence homology analysis did reveal a leader sequence and putative pyrroloquinoline quinone-binding domains, but no putative protein function . We excluded the possibility that SspJ is a scavenger of superoxide or has superoxide dismutase activity.

Infect Immun, 2001 Dec, 69(12), 7254 - 61
In vivo genetic analysis indicates that PhoP-PhoQ and the Salmonella pathogenicity island 2 type III secretion system contribute independently to Salmonella enterica serovar Typhimurium virulence; Beuzon CR et al.; Many virulence factors are required for Salmonella enterica serovar Typhimurium to replicate intracellularly and proliferate systemically within mice . In this work, we have carried out genetic analyses in vivo to determine the functional relationship between two major virulence factors necessary for systemic infection by S . enterica serovar Typhimurium: the Salmonella pathogenicity island 2 (SPI-2) type III secretion system (TTSS) and the PhoP-PhoQ two-component regulatory system . Although previous work suggested that PhoP-PhoQ regulates SPI-2 TTSS gene expression in vitro, in vivo competitive analysis of mutant strains indicates that these systems contribute independently to S . typhimurium virulence . Our results also suggest that mutation of phoP may compensate partially for defects in the SPI-2 TTSS by deregulating SPI-1 TTSS expression . These results provide an explanation for previous reports showing an apparent functional overlap between these two systems in vitro.

Asian Pac J Allergy Immunol, 2001 Jun, 19(2), 115 - 27
Validation of salmonellosis and shigellosis diagnostic test kits at a provincial hospital in Thailand; Sonjai K et al.; Rapid Diagnosis of salmonellosis and shigellosis was performed using six different diagnostic test kits which recently have been made available commercially . They were Salmo-Dot, Typhi-Dot, Shigel Dot A, B, C, and D test kits for detection of Salmonella spp., group D salmonellae, and groups A, B, C, and D Shigella spp., respectively . The principle of all test kits is a membrane (dot) ELISA using specific monoclonal antibodies to the respective pathogens as the detection reagents . The present study was designed to validate the accuracy of the test kits, at a laboratory in a provincial hospital in Thailand, in comparison with the conventional bacterial culture method alone or with the combined results of the culture and the Western blot analysis (WB) for detecting the respective bacterial lipopolysacchharides (LPS) in specimens . Five hundred rectal swab samples of patients with diarrhea who seeked treatment at the hospital, were evaluated . The diagnostic accuracy of the Salmo-Dot was 91.0% when compared with the conventional bacterial culture method alone but was 100.0% in comparison with the combined results of the culture and the WB . The Typhi-Dot and the Shigel-Dot A, B, C, and D showed 100%, 99.2%, 95.0%, 94.0% and 96.4%, respectively when compared with the culture alone and all were 100% in comparison with the combination of the results of the bacterial culture and the WB . The Shigel-Dot A revealed antigen of type 1 Shigella dysenteriae in several specimens in which the bacteria could not be recovered by the culture method . This difference is important as type 1 Shigella dysenteriae have high epidemic potential and often cause severe morbidity . Unawareness of their presence by the conventional culture may have great impact on disease surveillance for public health . The pathogen detection using the six diagnostic test kits is sensitive, specific, rapid, and relatively simple and less expensive . Several specimens can be tested at the same time without much increase in turn around time . Moreover, these kits produce no contaminated waste as compared with the bacterial culture method . The test kits should be used for rapid screening of specimens of patients with diarrhea especially in areas where culture facilities are inadequate.

Shock, 2001 Nov, 16(5), 389 - 92
Changes in vascular responsiveness to a thromboxane mimetic in endotoxin tolerance; Tempel GE et al.; Our previous studies have demonstrated that peritoneal macrophages obtained from endotoxin-tolerant rats exhibit altered cellular activation by endotoxin, possibly involving changes in guanine nucleotide regulatory (G) protein-coupled signal transduction pathways . Endotoxin-tolerant rats also exhibit cross tolerance and altered hemodynamic responses to thromboxane (Tx)A2 mimetics, suggesting potential changes in vascular responsiveness . We tested the hypothesis that endotoxin tolerance results in vascular hyporesponsiveness to a TxA2 mimetic via alterations in the TxA2 receptor, G protein function, and/or second messenger production . Rats were rendered endotoxin tolerant by increasing sublethal consecutive doses of Salmonella enteritidis endotoxin (100 to 5000 micrograms/kg, i.p.) for 4 days . The animals were sacrificed 2 days after the final dose of endotoxin for removal of aortas . Contractile responses of aortic rings to U46619, a TxA2 agonist, were assessed in control and tolerant rats . The EC50 values for U46619 were 14.8 +/- 6.6 nM and 32.3 +/- 3.1 nM (n = 5-7), (P < 0.05) for control and tolerant rats, respectively . Crude membranes were prepared from aortas of control and tolerant rats, and binding of I-BOP TxA2/PGH2 receptor agonist, {1S-(1 alpha, 2 beta (5Z), 3 alpha (1E, 3S*), 4 alpha)}-7-{3-(3-hydroxy-4-(4'-iodophenoxy)-1-butenyl)-7- oxabicyclo-{2.2.1}heptan-2-yl}-5-heptenoic acid (I-BOP), a TxA2 agonist, was assessed by Scatchard analysis . I-BOP binding to the TxA2 receptor was saturable and revealed a single class of TxA2 receptors for both groups . There was no significant difference in control (n = 7) compared with tolerant (n = 5) Kd values (2.1 +/- 0.2 vs . 2.4 +/- 0.9 nM, respectively), or Bmax (31 +/- 6 vs . 28 +/- 12 fmol/mg protein, respectively) . To assess potential changes in G protein function, aortic membrane GTpase activity was determined . GTPase activity in tolerant membranes was significantly reduced (P < 0.05) compared with control membranes (309 +/- 23 (n = 5) vs . 440 +/- 32 (n = 7) pmol/mg/protein/min, respectively) . However, U46619-stimulated phosphoinositide production was similar in vascular tissue from control and tolerant rats . These observations suggest that the decreased contractile response to TxA2 mimetics in endotoxin tolerance does not result from a change in receptor number, affinity of TxA2 receptors, or changes in phosphatidylinositol metabolism but is associated with decreased vascular G protein function.

J Bacteriol, 2001 Dec, 183(23), 6943 - 6
IS186 insertion at a hot spot in the lon promoter as a basis for lon protease deficiency of Escherichia coli B: identification of a consensus target sequence for IS186 transposition; saiSree L et al.; The radiation sensitivity of Escherichia coli B was first described more than 50 years ago, and the genetic locus responsible for the trait was subsequently identified as lon (encoding Lon protease) . We now show that both E . coli B and the first reported E . coli K-12 lon mutant, AB1899, carry IS186 insertions in opposite orientations at a single site in the lon promoter region and that this site represents a natural hot spot for transposition of the insertion sequence (IS) element . Our analysis of deposited sequence data for a number of other IS186 insertion sites permitted the deductions that (i) the consensus target site sequence for IS186 transposition is 5'-(G)(> or =4)(N)(3-6)(C)(> or =4)-3', (ii) the associated host sequence duplication varies within the range of 6 to 12 bp and encompasses the N(3-6) sequence, and (iii) in a majority of instances, at least one end of the duplication is at the G-N (or N-C) junction . IS186-related sequences were absent in closely related bacterium Salmonella enterica serovar Typhimurium, indicating that this IS element is a recent acquisition in the evolutionary history of E . coli.

J Am Vet Med Assoc, 2001 Nov 1, 219(9), 1216 - 20
Diversity of Salmonella serotypes in cull (market) dairy cows at slaughter; Galland JC et al.; OBJECTIVE: To determine the diversity of Salmonella serotypes isolated from a large population of cull (market) dairy cows at slaughter . DESIGN: Cross-sectional study . SAMPLE POPULATION: Salmonella organisms isolated from the cecal-colon contents of 5,087 market dairy cows . PROCEDURE: During winter and summer 1996, cecal-colon contents of cull dairy cows at slaughter were obtained from 5 US slaughter establishments . Specimens were subjected to microbiologic culturing for Salmonella spp at 1 laboratory . Identified isolates were compared with Salmonella isolation lists published by the Centers for Disease Control and Prevention (CDC) and the National Veterinary Services Laboratory (NVSL) for approximately the same period . The Simpson diversity index was used to calculate the likelihood that Salmonella isolates selected randomly by establishment were different . RESULTS: Of 58 Salmonella serotypes identified, Salmonella ser . Montevideo was the most prevalent . Two of the top 10 CDC serotypes identified from in 1996, Salmonella ser . Typhimurium and S Montevideo, appeared on our top 10 list; 8 of the top 10 were found on NVSL listings . Thirty-one of 59 S . Typhimurium isolates were identified as DT104 and found at a west slaughter establishment, 30 during the winter and 1 during the summer . The greatest diversity of serotypes was at a southeast establishment during the summer; the least diversity was at a central establishment in the winter . CONCLUSIONS AND CLINICAL RELEVANCE: 58 Salmonella serotypes were isolated from market dairy cows at slaughter and could pose a threat for food-borne illness . Salmonella Montevideo was the most frequently isolated serotype and may contribute substantially to salmonellosis in dairy cattle.

J Am Vet Med Assoc, 2001 Nov 1, 219(9), 1212 - 5
Prevalence of Salmonella spp in cull (market) dairy cows at slaughter; Troutt HF et al.; OBJECTIVE: To determine the prevalence of Salmonella spp in the cecal-colon contents of cull (market) dairy cows at slaughter because of potential public health ramifications . DESIGN: Survey study . SAMPLE POPULATION: Cecal-colon contents collected from 5,087 cull (market) dairy cows at slaughter at 5 slaughter establishments across the United States . PROCEDURE: During 2 periods of the year, winter (January and February) and summer (July through September), 5 cull (market) cow slaughter establishments in the United States--west (WE), southeast (SEE), central (CE), north central (NCE), and south central (SCE)--establishments were visited, and cecal-colon contents of cull dairy cows were obtained at the time of slaughter . Samples were examined by microbiologic culture at a single laboratory for Salmonella spp . RESULTS: Salmonella spp were detected in 23.1% of cecal-colon content samples from cull dairy cows across the 5 slaughter establishments . The highest site prevalence (54.5%) was detected at the WE during the summer period, whereas the lowest was found at the CE during the summer (4.3%) and at the NCE during the winter (4.5%) . Considerable variation in the daily prevalence of Salmonella spp was found, particularly at the WE and the SCE . Salmonella spp were isolated from 93% of cecal-colon contents collected on a summer day at the WE . CONCLUSIONS AND CLINICAL RELEVANCE: Results strongly suggest that there is a high prevalence of Salmonella spp in cull dairy cows at slaughter, which could burden Hazard Analysis Critical Control Point programs implemented in slaughter establishments . Procedures to reduce Salmonella load at the dairy farm and during transport to slaughter could reduce the risk of spread during the slaughter process.

Cell Microbiol, 2001 Nov, 3(11), 763 - 72
Epithelial cell contact-induced alterations in Salmonella enterica serovar Typhi lipopolysaccharide are critical for bacterial internalization; Lyczak JB et al.; The invasion of Pseudomonas aeruginosa and Salmonella enterica serovar Typhi into epithelial cells depends on the cystic fibrosis transmembrane conductance regulator (CFTR) protein as an epithelial receptor . In the case of P . aeruginosa, the bacterial ligand for CFTR is the outer core oligosaccharide portion of the lipopolysaccharide (LPS) . To determine whether serovar Typhi LPS is also a bacterial ligand mediating internalization, we used both P . aeruginosa and serovar Typhi LPS as a competitive inhibitor of serovar Typhi invasion into the epithelial cell line T84 . P . aeruginosa LPS containing a complete core efficiently inhibited serovar Typhi invasion . However, neither killed wild-type Typhi cells nor purified LPS were effective inhibitors . LPS from mutant Typhi strains defective in O side-chain synthesis, but with an apparently normal core, was capable of inhibiting invasion, but LPS obtained from a deeper rough mutant strain with alterations in fast-migrating core oligosaccharide failed to inhibit invasion . Lastly, exposure of wild-type serovar Typhi to T84 cultures before heat killing resulted in a structural alteration in its LPS that allowed the heat-killed cells to inhibit invasion of wild-type serovar Typhi . These data indicate that the serovar Typhi LPS core, like the P . aeruginosa LPS core, is a ligand mediating internalization of bacteria by epithelial cells, and that exposure of this ligand on wild-type Typhi is induced by the bacteria's interaction with host cells.

Cell Microbiol, 2001 Nov, 3(11), 753 - 62
Role of EscF, a putative needle complex protein, in the type III protein translocation system of enteropathogenic Escherichia coli; Wilson RK et al.; Type III secretion systems, designed to deliver effector proteins across the bacterial cell envelope and the plasma membrane of the target eukaryotic cell, are involved in subversion of eukaryotic cell functions in a variety of human, animal and plant pathogens . In enteropathogenic Escherichia coli (EPEC), several protein substrates for the secretion apparatus were identified, including EspA, EspB and EspD . EspA is a structural protein and the major component of a large transiently expressed filamentous surface organelle that forms a direct link between the bacterium and the host cell, whereas EspD and EspB seem to form the mature translocation pore . Recent studies of the type III secretion systems of Shigella and Salmonella pathogenicity island (SPI)-1 revealed the existence of a macromolecular complex that spans both bacterial membranes and consists of a basal structure with two upper and two lower rings and a needle-like projection that extends outwards from the bacterial surface . MxiH (Shigella) and PrgI (Salmonella) are the main components of the needle of the type III secretion complex . A needle-like complex has not yet been reported in EPEC . In this study, we investigated EscF, a protein sharing sequence similarity with MxiH and PrgI . We report that EscF is required for type III protein secretion and EspA filament assembly . Moreover, we show that EscF binds EspA, suggesting that EspA filaments are an extension of the type III secretion needle complexes in EPEC.

Biochemistry, 2001 Nov 13, 40(45), 13583 - 91
Structure of bacteriophage P22 portal protein in relation to assembly: investigation by Raman spectroscopy; Rodriguez-Casado A et al.; Salmonella phage P22, which serves as an assembly paradigm for icosahedral double-stranded DNA viruses, packages its viral genome through a capsid channel (portal) comprising 12 copies of a 725-residue subunit . Secondary and tertiary structures of the portal subunit in monomeric and dodecameric states have been investigated by Raman spectroscopy using a His6-tagged recombinant protein that self-assembles in vitro {Moore, S . D., and Prevelige, P . E., Jr . (2001) J . Biol . Chem . 276, 6779-6788} . The portal protein exhibits Raman secondary structure markers typical of a highly alpha-helical subunit fold that is little perturbed by assembly . On the other hand, Raman markers of subunit side chains change dramatically with assembly, an indication of extensive changes in side chain environments . The cysteinyl Raman signature of the portal consists of a complex pattern of sulfhydryl stretching bands, revealing diverse hydrogen-bonding states for the four S-H groups per subunit (Cys 153, Cys 173, Cys 283, and Cys 516) . Upon assembly, the population of strongly hydrogen-bonded S-H groups decreases, while the population of weakly hydrogen-bonded S-H groups increases, implying that specific intrasubunit S-H.X hydrogen bonds must be weakened to effect dodecamer assembly and that the molecular mechanism involves reorganization of subunit domains without appreciable changes in domain conformations . Comparison with other viral protein assemblies suggests an assembly process not requiring metastable intermediates . The recently published X-ray structure of the phi29 portal {Simpson, A . A., et al . (2000) Nature 408, 745-750} shows that residues 125-225 lining the channel surface form alpha-helical modules spaced by short beta-strands and turns; a surprisingly close secondary structure homology is predicted for residues 240-350 of the P22 portal, despite no apparent sequence homology . This motif is proposed as an evolutionarily conserved domain involved in DNA translocation.

Mar Pollut Bull, 2001 Oct, 42(10), 845 - 51
Mutagenicity of Baltic seawater and the relation to certain chemical and microbiological parameters; Zietz BP et al.; The presented work investigates the mutagenicity of seawater with regard to its distribution along the German Baltic Sea coastline . Further on in this paper the relationship between mutagenic activity and certain chemical, microbiological and physical parameters is analysed . Water samples were drawn from eight places between Eckernforde and Ribnitz-Damgarten . Seawater was concentrated using XAD-2/7 resin . Extracts of up to 3-l per plate were tested with the Salmonella mutagenesis assay employing the strains TA 98 and TA 100 with and without addition of S9-mixture for metabolic activation . Samples from Weissenhaus, Travemunde and Wismar demonstrated a mutagenic activity with the strain TA 98 . Tested filter sediment was not mutagenic . The sum of six polycyclic aromatic hydrocarbons (PAH) concentrated by XAD resin and obtained by high performance liquid chromatography (HPLC) were between 0.03 and 34.11 ng/l seawater . No correlation of measured mutagenicity and chemical or physical parameters could be established . The sampling place Wismar with one mutagenic sample had the highest number of colony forming units of Escherichia coli.

Epidemiol Infect, 2001 Oct, 127(2), 207 - 13
Secular trends in incidence and antimicrobial resistance among clinical isolates of Salmonella at a university hospital in Taiwan, 1983-1999; Su LH et al.; The incidence and antimicrobial resistance among clinical isolates of salmonella at a university hospital in Taiwan between 1983 and 1999 are summarized in this report . A total of 7986 isolates were analysed . Serogroup B has been the most prevalent over the years, with an apparently continuous decline after 1995 . Concordant decrease was also found among S . choleraesuis and S . typhi isolates in recent years . In contrast, the proportion of serogroup D strains increased significantly after 1996 . S . typhi remained relatively susceptible to most of the antimicrobial agents examined . For non-typhoidal isolates, antimicrobial resistance to ampicillin (62%), chloramphenicol (67%), and sulfamethoxazole-trimethoprim (37%) was relatively higher than that reported elsewhere . Newer generation cephalosporins and fluoroquinolones remained effective over the years, although emerging resistance to these drugs has been noticed since 1992 . A more prudent selection and use of antimicrobial agents, in both humans and animals, and a continuous surveillance of resistance are essential in the future.

Nature, 2001 Nov 1, 414(6859), 77 - 81
Maintenance of an unfolded polypeptide by a cognate chaperone in bacterial type III secretion; Stebbins CE et al.; Many bacterial pathogens use a type III protein secretion system to deliver virulence effector proteins directly into the host cell cytosol, where they modulate cellular processes . A requirement for the effective translocation of several such effector proteins is the binding of specific cytosolic chaperones, which typically interact with discrete domains in the virulence factors . We report here the crystal structure at 1.9 A resolution of the chaperone-binding domain of the Salmonella effector protein SptP with its cognate chaperone SicP . The structure reveals that this domain is maintained in an extended, unfolded conformation that is wound around three successive chaperone molecules . Short segments from two different SptP molecules are juxtaposed by the chaperones, where they dimerize across a hydrophobic interface . These results imply that the chaperones associated with the type III secretion system maintain their substrates in a secretion-competent state that is capable of engaging the secretion machinery to travel through the type III apparatus in an unfolded or partially folded manner.

Annu Rev Cell Dev Biol, 2001, 17, 53 - 86
Salmonella interactions with host cells: type III secretion at work; Galan JE; The bacterial pathogen Salmonella enterica has evolved a very sophisticated functional interface with its vertebrate hosts . At the center of this interface is a specialized organelle, the type III secretion system, that directs the translocation of bacterial proteins into the host cell . Salmonella spp . encode two such systems that deliver a remarkable array of bacterial proteins capable of modulating a variety of cellular functions, including actin cytoskeleton dynamics, nuclear responses, and endocytic trafficking . Many of these bacterial proteins operate by faithful mimicry of host proteins, in some cases representing the result of extensive molecular tinkering and convergent evolution . The coordinated action of these type III secreted proteins secures the replication and survival of the bacteria avoiding overt damage to the host . The study of this remarkable pathogen is not only illuminating general paradigms in microbial pathogenesis but is also providing valuable insight into host cell functions.

Clin Diagn Lab Immunol, 2001 Nov, 8(6), 1049 - 55
Evaluation of two enzyme-linked immunosorbent assays for detecting Salmonella enterica subsp . enterica Serovar Dublin antibodies in bulk milk; Veling J et al.; Two enzyme-linked immunosorbent assays (ELISAs) for the detecting Salmonella enterica subsp . enterica serovar Dublin antibodies in bulk milk were developed and evaluated for potential use in control programs . The ELISAs were based on either lipopolysacharide (LPS ELISA) or flagellar antigen (GP ELISA) . Sensitivity was determined with 79 case herds with a wide range of clinical signs . Specificity was determined with 125 Dutch and 200 Swedish control herds . The relation between antibodies in bulk milk, antibodies in serum, and the level of milk production of individual cows was studied with 61 case herds . The optimal optical density (OD) values of the LPS ELISA and the GP ELISA were determined to be 0.2 and 0.5, respectively . The sensitivities of the LPS ELISA and the GP ELISA were 54 and 63%, respectively, with a specificity of 98% for both ELISAs with samples from the Dutch control herds . The specificities for samples from the Swedish herds were 100% for the LPS ELISA and 95% for the GP ELISA . The sensitivity of the combination of tests was 65% when samples were run in parallel, and the specificity was 100% when samples were run in series, irrespective of whether the samples came from Dutch or Swedish control herds . The variance (R(2)) in the OD value for bulk milk samples could be explained by the percentage of seropositive lactating cows in a herd with the LPS ELISA for 51% of the samples and with the GP ELISA for 72% . The variance in the OD value was best explained by the combination of the percentage of seropositive lactating cows in the herd and the mean log(10) serum antibody titer for that herd (R(2) = 62% for the LPS ELISA and R(2) = 75% for the GP ELISA) . Case herds more often tested negative by the ELISA with bulk milk when the percentage of seropositive lactating cows was less than 5% . It is concluded that both ELISAs with bulk milk can be used in control programs to distinguish between infected and noninfected herds . Specificity can be increased by using the two tests in combination . Sensitivity was relatively low for both single tests and both tests combined.

Nat Struct Biol, 2001 Dec, 8(12), 1031 - 6
Structural and biochemical characterization of the type III secretion chaperones CesT and SigE; Luo Y et al.; Several Gram-negative bacterial pathogens have evolved a type III secretion system to deliver virulence effector proteins directly into eukaryotic cells, a process essential for disease . This specialized secretion process requires customized chaperones specific for particular effector proteins . The crystal structures of the enterohemorrhagic Escherichia coli O157:H7 Tir-specific chaperone CesT and the Salmonella enterica SigD-specific chaperone SigE reveal a common overall fold and formation of homodimers . Site-directed mutagenesis suggests that variable, delocalized hydrophobic surfaces observed on the chaperone homodimers are responsible for specific binding to a particular effector protein . Isothermal titration calorimetry studies of Tir-CesT and enzymatic activity profiles of SigD-SigE indicate that the effector proteins are not globally unfolded in the presence of their cognate chaperones.

Curr Microbiol, 2001 Oct, 43(4), 255 - 9
Aminopeptidase-N from the Helicoverpa armigera (Hubner) brush border membrane vesicles as a receptor of Bacillus thuringiensis crylac delta-endotoxin; Ingle SS et al.; Brush border membrane vesicles (BBMVs) were prepared from the 2nd instar larvae of Helicoverpa armigera . Binding of the activated Cry1Ac of Bacillus thuringiensis (Bt) toxin was shown by immunoblot . A 120-kDa protein was identified as a receptor for the Cry1Ac type delta-endotoxin . The aminopeptidase-N activity of BBMVs was measured as the hydrolysis of L-leucine p-nitroanilide . The specific activity was 35 units/mg protein . The BBMV preparation also showed low level of alkaline phosphatase activity . Zn++ chelating agents 2,2'-dipyridyl and 1,10-phenanthroline inhibited aminopeptidase activity at 10 mM concentration, indicating the presence of zinc-dependent aminopeptidase in the brush border of H . armigera . The aminopeptidase activity was increased with increasing concentration of delta-endotoxin . The purified 120-kDa binding protein was N-terminally sequenced . The first 10-amino-acid sequence showed 60-77% similarity with human cysteine-rich secretory protein-1 precursor, inhibin alpha chain precursor . Salmonella flagellar hook protein and yeast carboxypeptidase S.

J Clin Microbiol, 2001 Nov, 39(11), 3962 - 8
Characterization of Salmonella associated with pig ear dog treats in Canada; Clark C et al.; In the summer of 1999, the incidence of Salmonella enterica serotype Infantis infections in Alberta rose dramatically . Subsequent laboratory and epidemiological investigations established that an outbreak of human disease caused by this organism was occurring across Canada and was associated with pet treats for dogs produced from processed pig ears . Laboratory investigations using phage typing and pulsed-field gel electrophoresis (PFGE) established that isolates of Salmonella serotype Infantis from pig ear pet treats and humans exposed to pig ear pet treats comprised a well-defined subset of all isolates analyzed . Of the 53 subtypes of Salmonella serotype Infantis obtained around the time of the outbreak as defined by PFGE and phage typing, only 6 subtypes were associated with both human infection and isolation from pig ears . Together with information from epidemiological studies, these investigations established pig ear pet treats as the cause of the Salmonella serotype Infantis outbreak . The results are consistent with a model in which contaminated pig ear pet treats constitute a long-term, continuing vehicle for infection of the human population rather than causing temporally delimited point-source outbreaks . During the course of this outbreak, several other Salmonella serotypes were also isolated from pet treats, suggesting these products may be an important source of enteric infection in both humans and dogs . Though isolates of Salmonella serotypes other than Salmonella serotype Infantis from pet treats were also subjected to PFGE and phage typing, no link with human disease could be definitively established, and the contribution of pig ear pet treats to human disease remains unclear . Elimination of bacterial contamination from pet treats is required to reduce the risk of infection from these products.

FEMS Microbiol Lett, 2001 Oct 16, 204(1), 123 - 8
The rfaH gene, which affects lipopolysaccharide synthesis in Salmonella enterica serovar Typhi, is differentially expressed during the bacterial growth phase; Rojas G et al.; We have cloned and sequenced the rfaH gene from Salmonella enterica serovar Typhi strain Ty2 . The gene showed a high degree of similarity to the rfaH genes from Escherichia coli K-12 and S . enterica serovar Typhimurium . A rfaH mutant was constructed by site-directed mutagenesis . This mutant produced a rough lipopolysaccharide (LPS), with an incomplete core region . The defect in LPS expression that results from the rfaH mutation was corrected by a plasmid carrying the intact gene . The plasmid-borne rfaH gene also restored normal LPS synthesis in a rfaH mutant of E . coli . Reverse transcription-polymerase chain reaction analyses were performed to determine the effects of various environmental conditions on the expression of rfaH . The transcription of rfaH showed a growth-phase-dependent regulation, with maximal expression at the late exponential phase . Other environmental conditions, such as temperature or medium osmolarity, did not affect transcription of rfaH.

High Alt Med Biol, 2001 Fall, 2(3), 349 - 60
Atrial natriuretic peptide blockade exacerbates high altitude pulmonary edema in endotoxin-primed rats; Irwin DC et al.; High altitude pulmonary edema (HAPE) is associated with increases in pulmonary arterial and hydrostatic pressures and an increase in pulmonary vascular permeability . There is evidence to suggest that inflammatory mediators may cause some forms of HAPE, and Salmonella enteritidis endotoxin (ETX) is known to activate neutrophils and inflammatory mediators, such as TNF-alpha and IL1-beta . Since HAPE has been produced in rats primed with ETX, we hypothesized that ANP release and action may ameliorate HAPE and that ANP blockade may exacerbate HAPE in ETX-primed rats exposed to high altitude (HA) . Plasma ANP, right atrial ANP mRNA, and indexes of lung injury were measured in rats primed with endotoxin (ETX) (0.1 mg/kg BW, i.p.) and exposed to simulated HA (4267 m; P(B) = 440 mmHg) for either 12 or 24 h . Catheters were chronically inserted into the right carotid artery, pulmonary artery, and jugular vein for assessment of hemodynamic parameters in response to ETX and/or HA . In addition, some rats were injected with an antibody against ANP (alphaANP) prior to normoxic (NX) or HA exposure . Pulmonary arterial pressure increased in the alphaANP group (50 +/- 20%; p < or = 0.05) and in the HA + alphaANP (51 +/- 15%; p < or = 0.05) group at 12 h compared to NX sham rats injected with normal rabbit serum . In addition, systemic arterial pressure was significantly lower in the HA + ETX rats compared to HA + ETX + alphaANP rats (p < or = 0.001) . Plasma ANP levels were significantly higher at 12 and 24 h in ETX, HA, and HA + ETX groups (p <or = 0.05) compared to NX controls . There was an inverse relationship (p <or = 0.001) between plasma ANP levels and lung wet to dry (W/D) weight when data from NX, ETX, HA, and HA + ETX groups were pooled . The HA + alphaANP rats had significantly higher lung W/D ratios (p < 0.001) compared to sham rats . These results support the hypothesis that ANP, at physiological levels, modulates the development of pulmonary edema in HA-exposed ETX-primed rats.

Proc Nutr Soc, 2001 Aug, 60(3), 291 - 9
Development of antibiotic resistance and options to replace antimicrobials in animal diets; Bach Knudsen KE; As there is a risk of developing antibiotic resistance, a number of commonly-used antimicrobial growth promoters have been banned in the EU member states . This decision has put new emphasis on using the diet to control enteric bacterial infections of pigs . Dietary carbohydrates constitute a major proportion of diets for pigs, and the carbohydrate fraction has a diverse composition, with different properties in the gastrointestinal tract, some of which are of importance to gut health . Findings from different studies indicate that dietary carbohydrate composition influences the expression of swine dysentery and infection with nematode worms after experimental challenge with Brachyspira hyodesenteriae and Oesophagostumum dentatum respectively . In both cases the type, amount and physico-chemical properties of the carbohydrates entering the large intestine played an important role in the infection, and emerging data suggest a synergism between different porcine pathogens . There is also increasing evidence that the feed structure, which relates to the type of plant material in the diet and the way it is processed, can be used to reduce Salmonella prevalence at the herd level . However, it should be stressed that using the diet to manage gut health is not straightforward, since the expression of a pathogen in many cases requires the presence of other components of the commensal biota.

Eur J Clin Microbiol Infect Dis, 2001 Aug, 20(8), 558 - 65
Evaluation of a new chromogenic medium for the isolation and presumptive identification of Salmonella species from stool specimens; Eigner U et al.; The performance of BBL CHROMagar Salmonella (Becton Dickinson, France), a new selective chromogenic medium for the isolation and presumptive identification of Salmonella spp., was evaluated . On this medium, which is a modification of CHROMagar Salmonella (CHROMagar Microbiology, France) with enhanced selectivity, the colonies of Salmonella are stained in mauve (rose-violet), while those of other organisms appear in blue-green or are not stained by any of the chromogens of the medium . The medium was evaluated with a total of 176 strains of Salmonella and other organisms, consisting of 18 reference strains and 158 clinical isolates . All Salmonella strains except subspecies IIIa and IIIb strains and Salmonella Gallinarum yielded typical mauve colonies . During the evaluation with 107 known positive and 332 unknown stool specimens in a clinical laboratory, a total of 115 and 105 Salmonella isolates were obtained on BBL CHROMagar Salmonella and Hektoen enteric agar, respectively . From the known positive stool specimens, 92 true positive cultures were obtained on BBL CHROMagar Salmonella and 89 on Hektoen enteric agar, yielding sensitivities of 86 and 83%, respectively . From the unknown stool specimens, a total of 27 Salmonella isolates were obtained, with 23 isolated from BBL CHROMagar Salmonella and 16 from Hektoen enteric agar by direct plating (sensitivity 85 and 59%, specificity 99 and 97%, respectively) . Seroagglutination tests could be performed directly from BBL CHROMagar Salmonella . Compared to conventional isolation media, the time needed for confirmatory biochemical and serological tests was shortened by about 1 day when BBL CHROMagar Salmonella was used . On the basis of these results, the medium can be recommended for the primary isolation and presumptive identification of Salmonella spp . from clinical stool specimens.

Proteomics, 2001 Apr, 1(4), 597 - 607
Proteomic detection of PhoPQ- and acid-mediated repression of Salmonella motility; Adams P et al.; Salmonella adaptation to low pH is a critical survival response and essential for virulence . Here, we show that another key virulence-associated process, flagella-mediated cell motility, is co-regulated by low pH via the PhoPQ signal transduction system . Using a proteomic approach, we found that phase 1 and phase 2 flagellin were specifically down-regulated when acid-adapted (pH 5.0) Salmonella SL1344 cells were exposed to pH 3.0 . Decreased flagellin expression and cell motility was dependent on activation of the PhoPQ pathway, which directly or indirectly negatively regulated transcription of the flagellin gene fliC . In contrast, the general stress sigma factor RpoS (sigma s) positively regulated flagellar gene expression . Low external pH had no effect on the level of H-NS protein, a further regulator of flagellar gene expression . We suggest that flagellar repression at low pH conserves ATP for survival processes and helps to limit the influx of protons into the cytosol . These results highlight the power of proteomics to reveal unanticipated links between relatively well-characterised regulatory systems in bacteria.

J Mal Vasc, 2001 Oct, 26(4), 223 - 7
{Diagnosis of aortitis}; Hachulla E et al.; Aortitis can be a component of a variety of diseases, such as Takayasu arteritis, giant cell arteritis, Behcet's syndrome, Cogan's syndrome, spondylarthropathies, rheumatoid arthritis, systemic lupus erythematosus, sarcoidosis, Erdheim-Chester's disease and a variety of infectious processes like syphilis, Salmonella and others . The presentation is variable: aortic valve regurgitation, aneurysm, dissection, stenosis of the aorta or its initial branches . Sometimes systemic manifestations are at first presentation like fever or inflammatory syndrome . The differential diagnosis may be difficult in some situation like inflammatory aortic atherosclerotic aneurism, or retroperitoneal fibrosis . Some aortitis remain idiopathic . Corticosteroid and sometimes surgery are mostly required to avoid life-threatening complications.

Appl Environ Microbiol, 2001 Nov, 67(11), 4984 - 91
Identification by subtractive hybridization of sequences specific for Salmonella enterica serovar enteritidis; Agron PG et al.; Salmonella enterica serovar Enteritidis, a major cause of food poisoning, can be transmitted to humans through intact chicken eggs when the contents have not been thoroughly cooked . Infection in chickens is asymptomatic; therefore, simple, sensitive, and specific detection methods are crucial for efforts to limit human exposure . Suppression subtractive hybridization was used to isolate DNA restriction fragments present in Salmonella serovar Enteritidis but absent in other bacteria found in poultry environments . Oligonucleotide primers to candidate regions were used in polymerase chain reactions to test 73 non-Enteritidis S . enterica isolates comprising 34 different serovars, including Dublin and Pullorum, two very close relatives of Enteritidis . A primer pair to one Salmonella difference fragment (termed Sdf I) clearly distinguished serovar Enteritidis from all other serovars tested, while two other primer pairs only identified a few non-Enteritidis strains . These primer pairs were also useful for the detection of a diverse collection of clinical and environmental Salmonella serovar Enteritidis isolates . In addition, five bacterial genera commonly found with Salmonella serovar Enteritidis were not detected . By treating total DNA with an exonuclease that degrades sheared chromosomal DNA but not intact circular plasmid DNA, it was shown that Sdf I is located on the chromosome . The Sdf I primers were used to screen a Salmonella serovar Enteritidis genomic library and a unique 4,060-bp region was defined . These results provide a basis for developing a rapid, sensitive, and highly specific detection system for Salmonella serovar Enteritidis and provide sequence information that may be relevant to the unique characteristics of this serovar.

Biosens Bioelectron, 2001 Dec, 16(9-12), 1051 - 7
The thermostability of an alpha-helical coiled-coil protein and its potential use in sensor applications; Naik RR et al.; Coiled-coil proteins are assemblies of two to four alpha-helices that pack together in a parallel or anti-parallel fashion . Coiled-coil structures can confer a variety of functional capabilities, which include enabling proteins, such as myosin, to function in the contractile apparatus of muscle and non-muscle cells . The TlpA protein encoded by the virulence plasmid of Salmonella is an alpha-helical protein that forms an elongated coiled-coil homodimer . A number of studies have clearly established the role of TlpA as a temperature-sensing gene regulator, however the potential use of a TlpA in a thermo-sensor application outside of the organism has not been exploited . In this paper, we demonstrate that TlpA has several characteristics that are common with alpha-helical coiled-coils and its thermal folding and unfolding is reversible and rapid . TlpA is extremely sensitive to changes in temperature . We have also compared the heat-stability of TlpA with other structurally similar proteins . Using a folding reporter, in which TlpA is expressed as a C-terminal fusion with green fluorescent protein (GFP), we were able to use fluorescence as an indicator of folding and unfolding of the fusion protein . Our results on the rapid conformational changes inherent in TlpA support the previous findings and we present here preliminary data on the use of a GFP-TlpA fusion protein as temperature sensor.

Clin Microbiol Infect, 2001 Sep, 7(9), 479 - 85
Fluorescent amplified fragment length polymorphism genotyping of Salmonella Enteritidis: a method suitable for rapid outbreak recognition; Scott F et al.; OBJECTIVE: To perform fluorescent amplified fragment length polymorphism (FAFLP) analysis on phage type (PT) reference strains of Salmonella enterica subsp . enterica serotype Enteritidis (S . Enteritidis), and S . Enteritidis PT 6 and 6a recent clinical isolates to determine its usefulness for primary characterization of clinical S . Enteritidis isolates, and then to determine whether FAFLP is suitable for rapid characterization of strains in an outbreak situation . METHODS: Twenty-five PT reference strains of S . Enteritidis and 20 S . Enteritidis PT 6 and 6a clinical isolates were subjected to FAFLP analysis using the selective primer combinations Eco + 0-Mse + T and Eco + 0-Mse + TA . RESULTS: FAFLP successfully separated each one of the 25 S . Enteritidis PT strains into distinct profiles, while macrorestriction and PFGE using XbaI identified 20 pulsed-field profiles . FAFLP also resolved cases and outbreaks due to S . Enteritidis PTs 6 and 6a . CONCLUSIONS: The resolving power of FAFLP was higher than that of PFGE . FAFLP is a highly discriminatory genotyping method and, in conjunction with phage typing for primary subdivision of S . Enteritidis, provides a rapid and powerful tool for strain differentiation, both for outbreak investigation and for epidemiologic surveillance.

Curr Biol, 2001 Oct 16, 11(20), 1636 - 42
A PtdIns(3)P-specific probe cycles on and off host cell membranes during Salmonella invasion of mammalian cells; Pattni K et al.; Salmonella invade nonphagocytic cells by eliciting their own internalization; upon contact with the host cell, the bacteria induce membrane ruffles highly localized to the point of contact between the invading bacterium and the host cell . The bacterium is then internalized into an unusual cytosolic organelle, the Salmonella-containing vacuole (SCV) . Early endosomal markers (including EEA1) have recently been shown to be associated with the SCV shortly after invasion . EEA1, a protein involved in early endosome fusion, is recruited to early endosomal membranes in part by the interaction between its FYVE finger and phosphatidylinositol 3-phosphate {PtdIns(3)P}, a characteristic lipid of early endosomes . This suggests a possible role for PtdIns(3)P during Salmonella infection . To investigate this, we generated a highly specific probe for PtdIns(3)P that was used to follow invasion of Salmonella in nonphagocytic cells . Here, we show that PtdIns(3)P is present on the membranes of SCVs shortly after invasion and also that it is present on the membrane ruffles produced immediately prior to invasion . We also show that this specific probe cycles on and off the membranes of nascent SCVs even when PtdIns 3-kinase activity is inhibited, demonstrating that invading Salmonella influence the composition of the membranes that envelop them during invasion.

Euro Surveill, 2001 Jul-Aug, 6(8), 117 - 20
Evolution of antibiotic resistance of non-typhoidal salmonellae in Greece during 1990-97; Velonakis EN et al.; Susceptibility to 15 antibiotics was determined in 1548 non-typhoidal salmonella strains isolated in Greece from l990 to l997 . The overall prevalence of resistance of both Salmonella enterica serotype Enteritidis and Salmonella enterica serotype Typhimurium increased during the first years of the study . A decrease was observed from 1996, especially for S . Enteritidis, which showed the highest overall antibiotic resistance . S . Typhimurium was the serotype with the highest multiresistance to antibiotics . The rest of the serotypes had very low resistance prevalence compared with both S . Enteritidis and Typhimurium serotypes.

J Immunol, 2001 Nov 1, 167(9), 5304 - 15
IL-12p40-dependent agonistic effects on the development of protective innate and adaptive immunity against Salmonella enteritidis; Lehmann J et al.; To study a potential IL-12p40-dependent but IL-12p75-independent agonistic activity regulating the immune response against Salmonella Enteritidis, the course of infection in IL-12p35-deficient mice (IL-12p35(-/-), capable of producing IL-12p40) was compared with that of IL-12p40(-/-) mice . Mice lacking IL-12p40 revealed a higher mortality rate and higher bacterial organ burden than mice capable of producing IL-12p40 . This phenotype was found in both genetically susceptible (BALB/c, Ity(s)) and resistant mice (129Sv/Ev, Ity(r)) indicating Ity-independent mechanisms . The more effective control of bacteria in the IL-12p35(-/-) mice was associated with elevated serum IFN-gamma and TNF-alpha levels . In contrast, IL-12p40(-/-) mice showed reduced IFN-gamma production, which was associated with significantly elevated serum IgE levels . Early during infection (days 3 and 4 postinfection), as well as late (day 20 postinfection), the number of infected phagocytes was strongly increased in the absence of IL-12p40 indicating impaired bactericidal activity when IL-12p40 was missing . Liver histopathology revealed a decreased number of mononuclear granulomas in IL-12p40(-/-) mice . Depletion of CD4(+) or CD8(+) T lymphocytes in vivo suggested that both T cell subpopulations contribute to the IL-12p40-dependent protective functions . Analysis of IL-12p40 vs IL-23p19 mRNA expression revealed an up-regulation of only IL-12p40 mRNA during Salmonella infection . Together these data indicate that IL-12p40 can induce protective mechanisms during both the innate and the adaptive type 1 immune response in Salmonella infection . This novel activity of IL-12p40 complements the well described dominant and essential role of IL-12p75 in protective immunity to Salmonella infection.

J Bacteriol, 2001 Nov, 183(22), 6620 - 9
Hha is a negative modulator of transcription of hilA, the Salmonella enterica serovar Typhimurium invasion gene transcriptional activator; Fahlen TF et al.; An early step in the establishment of Salmonella enterica serovar Typhimurium murine infection is the penetration of the intestinal mucosa of the small intestine . The majority of the genes responsible for the Salmonella invasive phenotype are encoded on Salmonella pathogenicity island 1, and their transcription is controlled by the hilA transcriptional activator . The expression of hilA is regulated by environmental signals including oxygen, osmolarity, pH, and growth phase such that the presence of any one suboptimal condition results in repression of hilA expression and the invasive phenotype . We have conducted a search for negative regulators of hilA by introduction of a Salmonella enterica serovar Typhimurium chromosomal DNA gene bank into a Salmonella enterica serovar Typhimurium hilA::Tn5lacZY reporter strain . This screen has identified the hha gene as a regulator that exerts a negative influence on hilA expression . Plasmid-encoded hha significantly reduces hilA::Tn5lacZY chromosomal expression, as well as expression of the invasion genes invF, prgH, and sipC . An hha null mutation results in substantial derepression of both chromosomally encoded and plasmid-encoded hilA::Tn5lacZY expression . Introduction of plasmid-encoded hha into strain SL1344 results in attenuation of invasion using in vitro and in vivo assays . Importantly, purified Hha protein was found to bind to a hilA DNA promoter fragment, suggesting that the regulatory activity of the Hha protein occurs at the hilA promoter . These data add detail to the developing model of the regulation of Salmonella invasion genes.

J Bacteriol, 2001 Nov, 183(22), 6543 - 50
In vivo expression from the RpoS-dependent P1 promoter of the osmotically regulated proU operon in Escherichia coli and Salmonella enterica serovar Typhimurium: activation by rho and hns mutations and by cold stress; Rajkumari K et al.; Unlike the sigma(70)-controlled P2 promoter for the osmotically regulated proU operon of Escherichia coli and Salmonella enterica serovar Typhimurium, the sigma(s)-controlled P1 promoter situated further upstream appears not to contribute to expression of the proU structural genes under ordinary growth conditions . For S . enterica proU P1, there is evidence that promoter crypticity is the result of a transcription attenuation phenomenon which is relieved by the deletion of a 22-base C-rich segment in the transcript . In this study, we have sought to identify growth conditions and trans-acting mutations which activate in vivo expression from proU P1 . The cryptic S . enterica proU P1 promoter was activated, individually and additively, in a rho mutant (which is defective in the transcription termination factor Rho) as well as by growth at 10 degrees C . The E . coli proU P1 promoter was also cryptic in constructs that carried 1.2 kb of downstream proU sequence, and in these cases activation of in vivo expression was achieved either by a rho mutation during growth at 10 degrees C or by an hns null mutation (affecting the nucleoid protein H-NS) at 30 degrees C . The rho mutation had no effect at either 10 or 30 degrees C on in vivo expression from two other sigma(s)-controlled promoters tested, those for osmY and csiD . In cells lacking the RNA-binding regulator protein Hfq, induction of E . coli proU P1 at 10 degrees C and by hns mutation at 30 degrees C was still observed, although the hfq mutation was associated with a reduction in the absolute levels of P1 expression . Our results suggest that expression from proU P1 is modulated both by nucleoid structure and by Rho-mediated transcription attenuation and that this promoter may be physiologically important for proU operon expression during low-temperature growth.

Vaccine, 2001 Nov 12, 20(3-4), 623 - 9
Mucosal and systemic HIV-1 Env-specific CD8(+) T-cells develop after intragastric vaccination with a Salmonella Env DNA vaccine vector; Shata MT et al.; CD8(+) T-cell responses provide beneficial antiviral immunity against human immunodeficiency virus 1 (HIV-1) . In this study, we show that intragastric vaccination with a Salmonella HIV-1 Env DNA vaccine vector generates Env-specific CD8(+) T-cells, both in mucosal and systemic lymphoid tissue . By contrast, intramuscular vaccination with the Env DNA vaccine alone only induced systemic CD8(+) T-cells . To our knowledge, this is the first report showing both mucosal and systemic CD8(+) T-cell responses following vaccination with a Salmonella vaccine vector . These data suggest that this mode of HIV-1 DNA vaccine delivery will be advantageous over parenterally administered HIV-1 DNA vaccines.

Indian J Pediatr, 2001 Sep, 68(9), 839 - 41
Childhood bacterial meningitis in Pondicherry, South India; Sahai S et al.; OBJECTIVE: To identify causative bacteria from cerebrospinal fluid (CSF) of children with meningitis and analyse various clinical and laboratory parameters . METHODS: Over a 20 month period, September 1994 to April 1996, one hundred episodes of acute bacterial meningitis in children aged 1 month-12 years were studied in a tertiary urban hospital in South India . Organisms were isolated from the cerebrospinal fluid (CSF) in 35% of cases . Among infants and children, the two major pathogens were H . influenzae (17%) and S . pneumoniae (12%) . RESULTS: The illness at presentation was mild in 13% and severe in 36% of cases . The association of subdural effusion in children with Salmonella Gp B meningitis merits attention . The overall case fatality rate was 25% . S . pneumoniae had a higher case fatality rate than Salmonella Gp B and H . influenzae (50% vs 17% vs 12%) . All the three infants below 3 months of age with S . pneumoniae meningitis died . On analysis of selected clinical and laboratory features by discriminant analysis, CSF culture was the significant (P = 0.02) variable in relation to outcome . In pneumococcal meningitis, CSF WBC count was a highly significant variable in relation to outcome (Wilk's Lambda 0.15, F = 24.64, P = 0.0002) . CONCLUSION: Prevention of infections due to H . influenzae and S . pneumoniae should be given higher priority.

Amino Acids, 2001, 21(2), 161 - 74
Substrate recognition by proline permease in Salmonella; Liao MK et al.; Proline transport is required for catabolism of proline as a carbon, nitrogen, and energy source, and for accumulation of proline during adaptation to osmotic stress . These physiological processes are widespread in nature, and play essential roles in the virulence of both prokaryotic and eukaryotic pathogens . In enteric bacteria, the major proline permease is encoded by the putP gene . To identify the structural features required for substrate recognition by PutP, we assayed the transport and toxicity of a variety of natural and synthetic derivatives of proline . The results indicate that the substrate binding site of proline permease consists of a hydrophobic pocket that accommodates C3, C4, and C5 of the pyrrolidine ring . Both 4- and 5-membered rings fit into the substrate binding pocket, but 6-membered rings are excluded . Analogs with substituents on the C4 position are also excluded . In addition, the binding site includes a hydrophilic region that recognizes the imino and carbonyl groups . A free carboxyl group is not required . Taken together, these results may be used to design new synthetic inhibitors of proline transport that can effectively block proline uptake by microbial pathogens.

Indian J Med Sci, 2001 Apr, 55(4), 189 - 94
Decreasing clinical response of quinolones in the treatment of enteric fever; John M; Multidrug resistant Salmonella infections in India have been encountered since 1990, for which Quinolones were introduced at that time . However, with indiscriminate use of Quinolones, the sensitivity of these drugs when used alone, to treat S . typhi and S . paratyphi are decreasing . From 1997 to 1999, we have noted a gradual decrease in clinical efficacy of Quinolone monotherapy in enteric fever (9.3% in 1997, 20% in 1998 and 34.88% in 1999) . Hence we recommend the use of multidrug therapy for Quinolone resistant and complicated enteric fever . Addition of Ceftriaxone and/or Aminoglycoside is recommended.

Prog Nucleic Acid Res Mol Biol, 2001, 70, 175 - 206
Structure and function of branched chain aminotransferases; Hutson S; Branched chain aminotransferases (BCATs) catalyze transamination of the branched chain amino acids (BCAAs) leucine, isoleucine, and valine . Except for the Escherichia coli and Salmonella proteins, which are homohexamers arranged as a double trimer, the BCATs are homodimers . Structurally, the BCATs belong to the fold type IV class of pyridoxal phosphate (PLP) enzymes . Other members are D-alanine aminotransferase and 4-amino-4-deoxychorismate lyase . Catalysis is on the re face of the PLP cofactor, whereas in other classes, catalysis occurs from the si face of PLP . Crystal structures of the fold type IV proteins show that they are distinct from the fold type I aspartate aminotransferase family and represent a new protein fold . Because the fold type IV enzymes catalyze diverse reactions, it is not surprising that the greatest structural similarities involve residues that participate in PLP binding rather than residues involved in substrate binding . The BCATs are widely distributed in the bacterial kingdom, where they are involved in the synthesis/degradation of the BCAAs . Bacteria contain a single BCAT . In eukaryotes there are two isozymes, one is mitochondrial (BCATm) and the other is cytosolic (BCATc) . In mammals, BCATm is in most tissues, and BCATm is thought to be important in body nitrogen metabolism . BCATc is largely restricted to the central nervous system (CNS) . Recently, BCATc has been recognized as a target of the neuroactive drug gabapentin . BCATc is involved in excitatory neurotransmitter glutamate synthesis in the CNS . Ongoing structural studies of the BCATs may facilitate the design of therapeutic compounds to treat neurodegenerative disorders involving disturbances of the glutamatergic system.

N Engl J Med, 2001 Oct 18, 345(16), 1147 - 54
The isolation of antibiotic-resistant salmonella from retail ground meats; White DG et al.; BACKGROUND: Salmonella is a leading cause of foodborne illness . The emergence of antimicrobial-resistant salmonella is associated with the use of antibiotics in animals raised for food; resistant bacteria can be transmitted to humans through foods, particularly those of animal origin . We identified and characterized strains of salmonella isolated from ground meats purchased in the Washington, D.C., area . METHODS: Salmonella was isolated from samples of ground chicken, beef, turkey, and pork purchased at three supermarkets . The isolates were characterized by serotyping, antimicrobial-susceptibility testing, phage typing, and pulsed-field gel electrophoresis . The polymerase chain reaction and DNA sequencing were used to identify resistance integrons and extended spectrum beta-lactamase genes . RESULTS: Of 200 meat samples, 41 (20 percent) contained salmonella, with a total of 13 serotypes . Eighty-four percent of the isolates were resistant to at least one antibiotic, and 53 percent were resistant to at least three antibiotics . Sixteen percent of the isolates were resistant to ceftriaxone, the drug of choice for treating salmonellosis in children . Bacteriophage typing identified four isolates of Salmonella enterica serotype typhimurium definitive type 104 (DT104), one of DT104b, and two of DT208 . Five isolates of S . enterica serotype agona had resistance to 9 antibiotics, and the two isolates of serotype typhimurium DT208 were resistant to 12 antibiotics . Electrophoretic patterns of DNA that were indistinguishable from one another were repeatedly found in isolates from different meat samples and different stores . Eighteen isolates, representing four serotypes, had integrons with genes conferring resistance to aminoglycosides, sulfonamides, trimethoprim, and beta-lactams . CONCLUSIONS: Resistant strains of salmonella are common in retail ground meats . These findings provide support for the adoption of guidelines for the prudent use of antibiotics in food animals and for a reduction in the number of pathogens present on farms and in slaughterhouses . National surveillance for antimicrobial-resistant salmonella should be extended to include retail meats.

J Ind Microbiol Biotechnol, 2001 Aug, 27(2), 126 - 8
Use of bioluminescent Salmonella for assessing the efficiency of constructed phage-based biosorbent; Sun W et al.; A bacteriophage-based biosorbent for Salmonella enteritidis was constructed, and bacterial bioluminescence was used for assessment of the efficiency of cell capture . A strain of S . enteritidis with bioluminescent phenotype was constructed by transformation with plasmid pT7 carrying the entire lux operon from Photorhabdus luminescens . The relation between relative light output (RLU) and colony-forming units (CFU/ml) of the bioluminescent strain was established . The bacteriophage specific to S . enteritidis was biotinylated, and the biotinylation procedure was optimized based on the maximum retention of phage infectivity . The biotinylated phages were then coated onto streptavidin-labeled magnetic beads, and were used to capture the bioluminescent S . enteritidis cells . Our preliminary results showed that the number of cells captured by constructed biosorbent was five times higher than that of the control, magnetic beads coated with nonbiotinylated phage, indicating the capture is specific.

Kansenshogaku Zasshi, 2001 Sep, 75(9), 815 - 8
{Multidrug-resistant and fluoroquinolone-resistant Salmonella enterica serotype Typhimurium definitive phage type 12 isolated from infantile diarrhea}; Nakaya H et al.; A 35-day-old male infant was admitted to our hospital, presenting a high fever, vomiting, and diarrhea . Multidrug-resistant and fluoroquinolon-resistant Salmonella serotype Typhimurium was isolated from his stool . The phage type of the strain was DT12 . The strain was resistant to ampicillin, streptomycin, gentamicin, tetracycline, chloramphenicol, sulfamethoxazole-trimethoprim, and fluoroquinolones (levofloxacin; MIC 8 micrograms/ml, norfloxacin; 24 micrograms/ml, ciprofloxacin; 16 micrograms/ml, sparfloxacin; 32 micrograms/ml) . He was cured by antibiotic therapy using fosfomycin (< or = 1 microgram/ml) . We could not determine a route of infection . Domestic surveillance for fluoroquinolon-resistant Sallmonella is necessary.

Ann Rheum Dis, 2001 Nov, 60(11), 1055 - 7
Low incidence of reactive arthritis in children following a salmonella outbreak; Rudwaleit M et al.; OBJECTIVES: To assess the incidence of reactive arthritis (ReA) in an outbreak of salmonella infection in a large cohort of children in Germany . METHODS: A few days after the salmonella outbreak all parents of affected children and all paediatricians and general practitioners in the region were provided with detailed information about the possibility of ReA . Six weeks after the outbreak a telephone call was made to all general practitioners and paediatricians to identify patients with ReA . Ten weeks after the outbreak a questionnaire assessing symptoms of ReA was mailed to all parents, and after a period of 4 months paediatricians and general practitioners were contacted again to search for additional unreported cases of ReA . RESULTS: Of the 286 children (age range 11 months to 9 years) with diarrhoea and stool cultures positive for Salmonella enteritidis lysotype 8/7, not a single case of arthritis was reported over the 4 month period . However, six children (2%) had arthralgia of various duration (1 day to 6 weeks) with a single recurrence in one child . The joint pattern was oligoarticular and lower limb joints (knee/ankle) were affected exclusively . CONCLUSION: The incidence of ReA after salmonella infection in children appears to be very low which may be related to differences in the immune response between children and adults.

J Food Prot, 2001 Oct, 64(10), 1621 - 3
Effect of chlorine, sodium chloride, trisodium phosphate, and ultraviolet radiation on the reduction of Yersinia enterocolitica and mesophilic aerobic bacteria from eggshell surface; Favier GL et al.; Eggshell sanitizing practices are necessary to improve microbiological safety of fresh hen eggs and their products . In this work, the effects of 100 mg/liter free chlorine (chl), 3% sodium chloride (NaCl), 1, 5, and 12% trisodium phosphate (TSP) in wash solutions, and UVR (ultraviolet radiation; 4.573 microW/cm2) were studied at different times on uninoculated and Yersinia enterocolitica-inoculated eggs . On uninoculated eggs, the best results were obtained with 100 mg/liter chlorine and UV exposure for >25 min, with reductions of 1.28 and 1.60 log cycles, respectively, compared to the average bacterial count (4.55 log CFU/egg) on the control (untreated eggs) . On Y . enterocolitica-inoculated eggs, highest reductions of the average bacterial count (7.35 log CFU/egg) were obtained with 5 and 12% TSP and 100 mg/liter chl . The decrease obtained with 12% TSP (3.74-log reduction) was significantly higher (P < 0.05) than those obtained with the remaining treatments . Y . enterocolitica was more resistant to UVR than the eggshell natural mesophilic aerobic microflora, except when low inoculum (4.39 log CFU/egg) was assayed . Changes in eggshell microstructure were measured by the blue lake staining method . The presence of Yersinia and Salmonella in eggshell natural flora was also investigated.

J Food Prot, 2001 Oct, 64(10), 1549 - 55
Process lethality and product yield for chicken patties processed in a pilot-scale air-steam impingement oven; Murphy RY et al.; Chicken breast patties were processed in a pilot-scale air-steam impingement oven to a patty center temperature of 55 to 80 degrees C . Thermal processing was conducted at an air temperature of 149 degrees C, an air velocity of 7 to 13 m3/min, and a wet bulb temperature of 39 to 98 degrees C . From thermal histories, the total process lethality of the patties was calculated for Salmonella spp . and Listeria innocua using the previously published z-values . The effect of product temperature, wet bulb temperature, and air velocity on process lethality was analyzed using a regression model . The process lethality of Salmonella spp . and L . innocua in the cooked chicken patties was correlated to the patty center temperatures and cooking conditions . The process lethality was strongly correlated to product temperature and was affected by cooking conditions . Process lethality started to increase rapidly at the product temperature around 67 degrees C . Regression analysis was used to correlate the product yield with cooking conditions . Depending on air velocity, product yield decreased 10 to 14% with increasing endpoint temperature from 55 to 80 degrees C and increased 2 to 9% with increasing wet bulb temperature from 39 to 98 degrees C . The effect of air velocity on the yield interacted with product temperature and wet bulb temperature.

J Food Prot, 2001 Oct, 64(10), 1542 - 8
Efficacy of chitosan, carvacrol, and a hydrogen peroxide-based biocide against foodborne microorganisms in suspension and adhered to stainless steel; Knowles J et al.; The ability of natural compounds to inactivate foodborne organisms adhered to surfaces was investigated with the ultimate aim of replacing synthetic biocides by more environmentally friendly, natural alternatives . The antimicrobial efficacy of 0.5, 1.0, and 2.0% chitosan and Spor-Klenz RTU (a commercial biocide based on hydrogen peroxide and peroxyacetic acid) and 0.5, 1.25, and 2.0 mM carvacrol was determined at 20 degrees C against Listeria monocytogenes, Salmonella enterica serovar Typhimurium, Staphylococcus aureus, and Saccharomyces cerevisiae adhered to stainless steel disks . Treatment with up to 2.0% chitosan reduced the viable cell count in the microbial films of the four test organisms by 2.4, 1.8, 2.3, and 0.9 log CFU/test surface (t.s.), respectively . By contrast, planktonic counts of the same organisms were reduced by 0.8 to 1.7 log CFU/ml at 2.0% chitosan . Treatment with 2 mM carvacrol reduced the viable counts of adhered listeriae, salmonellae, and yeasts by 2 to 3 log CFU/t.s . but S . aureus counts were reduced by only 0.9 log CFU/t.s . The efficacy of any single compound was species specific . In the case of microbial films prepared using listeriae and salmonellae, Spor-Klenz RTU was most biocidal, followed by carvacrol and then chitosan . However, dried films of S . aureus were most sensitive to chitosan and relatively resistant to carvacrol and Spor-Klenz RTU . By contrast, yeast films were most sensitive to carvacrol and least sensitive to chitosan . It was concluded that carvacrol and chitosan may have potential for use as natural biocides although optimization of conditions would be necessary.

J Food Prot, 2001 Oct, 64(10), 1503 - 9
Chicken mim-1 protein, P33, is a heterophil chemotactic factor present in Salmonella enteritidis immune lymphokine; Bischoff KM et al.; Lymphokine (ILK) secreted from concanavalin A-stimulated T cells from Salmonella Enteritidis-immune chickens is an undefined mixture of proteins that confers protection against Salmonella infectivity when administered to day-old chicks . It has previously been shown that polyclonal antibodies raised against human granulocyte colony-stimulating factor (GCSF) can neutralize the heterophil activation that is responsible for ILK's protective effect . Western blot analysis of ILK probed with anti-GCSF antibodies detects a prominent protein of mass 33 kDa . We have sequenced the first 20 amino acids of this protein and found it to be identical to residues 24 to 43 of P33, a 326-amino acid protein of unknown function encoded by the chicken mim-1 gene . The primary structure of P33 consists of two 140-residue imperfect repeats that are each homologous to a mammalian neutrophil chemotactic factor termed leukocyte cell-derived chemotaxin 2 (LECT2) . We have expressed mim-1 in Escherichia coli and demonstrated in vitro that recombinant P33 is chemotactic for heterophils, the avian equivalent of mammalian neutrophils . We have also constructed a derivative of P33 that consists of residues 33 to 165 (P33{33-165}), the first repeat sequence of P33 that is homologous to LECT2 . P33(33-165) is chemotactic for heterophils both in vitro and in vivo, inducing an influx of heterophils into the peritoneum in a response similar to that observed with ILK . These results suggest that P33 functions as a chemotactic factor in chickens and that it plays an active role in ILK-mediated protection against Salmonella infection.

J Food Prot, 2001 Oct, 64(10), 1496 - 502
Prevalence of antimicrobial resistance in Salmonellae isolated from market-age swine; Farrington LA et al.; Antimicrobial resistance levels were examined for 365 Salmonella isolates recovered from the lymph nodes (n = 224) and cecal contents (n = 141) of market-age swine at slaughter . Antimicrobial resistance testing was performed by disk diffusion using 13 antibiotics common in the treatment of disease in human and veterinary medicine . Although none of the antibiotics tested were used subtherapeutically within the last 5 years on the farms sampled, resistance to chlortetracycline, penicillin G, streptomycin, and sulfisoxazole was common . Penicillin G resistance was significantly more frequent (P = 0.03) and sulfisoxazole resistance was significantly less frequent (P < 0.01) in lymph node versus cecal isolates . Multidrug resistance was observed among 94.7% of the lymph node isolates and 93.5% of the cecal isolates . The most frequent multidrug resistance pattern included three antibiotics-penicillin G, streptomycin, and chlortetracycline . Isolates in somatic serogroup B, and more specifically, Salmonella Agona and Salmonella Schwarzengrund isolates, were often resistant to a greater number of antibiotics than were isolates in the other serogroups . Streptomycin, sulfisoxazole, ampicillin (lymph node isolates), and nitrofurantoin (cecal isolates) resistance levels differed significantly between somatic serogroups . The prevalence of penicillin G-, streptomycin-, and sulfisoxazole-resistant isolates differed significantly between serovars for both lymph node and cecal isolates . Results of this study suggest that a correlation exists between the somatic serogroup or serovar of a Salmonella isolate and its antimicrobial resistance status, which is specific to the antibiotic of interest and the source of the isolate (lymph node versus cecal contents).

J Food Prot, 2001 Oct, 64(10), 1489 - 95
Efficacy of chemical treatments in eliminating Salmonella and Escherichia coli O157:H7 on scarified and polished alfalfa seeds; Holliday SL et al.; Alfalfa seeds are sometimes subjected to a scarification treatment to enhance water uptake, which results in more rapid and uniform germination during sprout production . It has been hypothesized that this mechanical abrasion treatment diminishes the efficacy of chemical treatments used to kill or remove pathogenic bacteria from seeds . A study was done to compare the effectiveness of chlorine (20,000 ppm), H2O, (8%), Ca(OH)2 (1%), Ca(OH)2 (1%) plus Tween 80 (1%), and Ca(OH)2 (1%) plus Span 20 (1%) treatments in killing Salmonella and Escherichia coli O157:H7 inoculated onto control, scarified, and polished alfalfa seeds obtained from two suppliers . The influence of the presence of organic material in the inoculum carrier on the efficacy of sanitizers was investigated . Overall, treatment with 1% Ca(OH)2 was the most effective in reducing populations of the pathogens . Reduction in populations of pathogens on seeds obtained from supplier I indicate that chemical treatments are less efficacious in eliminating the pathogens on scarified seeds compared to control seeds . However, the effectiveness of chemical treatment in removing Salmonella and E . coli O157:H7 from seeds obtained from supplier 2 was not markedly affected by scarification or polishing . The presence of organic material in the inoculum carrier did not have a marked influence on the efficacy of chemicals in reducing populations of test pathogens . Additional lots of control, scarified, and polished alfalfa seeds of additional varieties need to be tested before conclusions can be drawn concerning the impact of mechanical abrasion on the efficacy of chemical treatment in removing or killing Salmonella and E . coli O157:H7.

J Food Prot, 2001 Oct, 64(10), 1483 - 8
Survival of Salmonella spp . and Escherichia coli O157:H7 on fresh and frozen strawberries; Knudsen DM et al.; For maximum shelf life, fresh strawberries are harvested directly without washing into retail containers . Frozen berries are usually hulled in the field and washed prior to freezing, sometimes with the addition of sucrose . To determine survival of potential bacterial contaminants, cut or intact surfaces of fresh strawberries were spot inoculated with five- or six-strain cocktails of Salmonella or Escherichia coli O157:H7 (log 7.0 CFU/sample) . Inoculated strawberries were dried for 1 h at 24 degrees C and were stored in closed containers at 5 or 24 degrees C . Sliced strawberries with or without added 20% sucrose were inoculated with one of two strains of E . coli O157:H7 and frozen at -20 degrees C . An initial population reduction of approximately 0.5-log cycles was observed on intact but not cut berries after the 1-h drying period . During storage at 24 degrees C for up to 48 h, populations of Salmonella and E . coli O157:H7 did not decline further . When strawberries were stored at 5 degrees C for up to 7 days, populations of both pathogens remained constant on cut surfaces but decreased by 1 - to 2-log cycles on intact surfaces . After 30 days of frozen storage, the population of E . coli O157:H7 had declined by 0.7- to 2.2-log cycles (with and without sucrose, respectively) . Results of this study indicate that E . coli O157:H7 and Salmonella are capable of survival but not growth on the surface of fresh strawberries throughout the expected shelf life of the fruit and can survive in frozen strawberries for periods of greater than 1 month.

J Food Prot, 2001 Oct, 64(10), 1477 - 82
Efficacy and reproducibility of a produce wash in killing Salmonella on the surface of tomatoes assessed with a proposed standard method for produce sanitizers; Harris LJ et al.; The reproducibility of a method developed to evaluate point-of-use sanitizers for fresh produce was tested at three different laboratories . Mixtures of five Salmonella serotypes were inoculated on the surface of ripe tomatoes . After the inoculum was dry, tomatoes were placed inside a plastic bag and sprayed with sterile USP water, Dey and Engley (D/E) neutralizer broth, or a prototype Fit produce wash (PW), an alkaline solution comprised of generally recognized as safe ingredients (water, oleic acid, glycerol, ethanol, potassium hydroxide, sodium bicarbonate, citric acid, and distilled grapefruit oil), and rubbed for 30 s . The tomatoes were rinsed 10 s with 195 ml of D/E neutralizer broth (rinse solution), then combined with 20 ml of D/E neutralizer (residual wash solution) and rubbed by hand to remove residual Salmonella . Populations of Salmonella were determined for each tomato in the rinse solution and residual wash solution . Treatment with PW resulted in reductions in the number of Salmonella 2 to 4 logs greater than those achieved with the sterile water or D/E neutralizer broth controls . Consistent results were obtained across the three study sites, indicating reproducible results were obtained using the test method . The method used to determine the efficacy of killing or removing Salmonella from tomatoes in this study is suggested as a standard method for measuring the efficacy of sanitizers on tomatoes and other similar fruits and vegetables with rigid, smooth surfaces.

J Food Prot, 2001 Oct, 64(10), 1472 - 6
Improving recovery of Salmonella enterica serovar typhimurium DT104 cells injured by heating at different water activity values; Mattick KL et al.; This study describes the evaluation of potentially more sensitive methods for the recovery of Salmonella cells injured by heating (54 to 60 degrees C) at different water activity values (0.65 to 0.90, reduced using equal portions of glucose and fructose) . These methods included gradual rehydration, the use of diluting media with added solutes or blood, the addition of blood to plating agar, and the use of different incubation temperatures and times . Gradual rehydration of cells that had been challenged at low water activity (0.65 and 0.70) and high temperature markedly improved recovery, measured as a >50% increase in the time to obtain a 3-log10 reduction in cell numbers, compared to dilution into media with a high water activity . Adding sucrose, glycerol, or blood to the diluting media (maximal recovery diluent) did not improve recovery, but a plating agar containing blood recovered approximately 38% more cells than nutrient agar . Prolonged incubation of agar plates allowed recovery of injured Salmonella cells that presumably had extended lag periods, with significantly higher recovery rates after 48 h incubation at 37 degrees C than after 24 h (P = 0.05) . This work highlights that by recovering Salmonella using a method specific to the nature of the injury, a better prediction of food safety and the success of food processing can be made.

J Food Prot, 2001 Oct, 64(10), 1459 - 65
Comparison of sample preparation methods for recovering Salmonella from raw fruits, vegetables, and herbs; Burnett AB et al.; Methods for preparing raw fruits, vegetables, and herbs for enrichment or direct plating to determine the presence and populations of pathogenic bacteria vary greatly . A study was done to compare three sample processing methods (washing in 0.1% peptone, stomaching, and homogenizing) for their influence on recovery of Salmonella inoculated onto 26 types of raw produce . The mean numbers of Salmonella recovered from 10 fruits, 11 vegetables, and 5 herbs using all three processing methods were 7.17, 7.40, and 7.27 log10 CFU/sample, respectively . Considering all 26 types of produce and all processing methods, the number of Salmonella recovered ranged from 7.24 to 7.29 log10 CFU/sample, with no significant differences attributable to a particular sample processing method . Mean percent recoveries of Salmonella from washed, stomached, and homogenized produce were 39.4, 44.7, and 42.4%, respectively . Mean percent recoveries from fruits, vegetables, and herbs, regardless of sample preparation method, were 41.7, 50.1, and 25.9%, respectively . The number of Salmonella recovered from stomached and homogenized produce, but not washed produce, with pH < or = 4.53 was significantly less than the number recovered from produce with pH from 5.53 to 5.99, suggesting that the acidic environment in stomachates and homogenates was lethal to a portion of Salmonella . Reduced percent recoveries from herbs (pH 5.94 to 6.34) is attributed, in part, to antimicrobials released from plant cells during sample preparation . Overall, the type of processing method did not substantially affect the number of Salmonella recovered from the 26 types of raw produce representing a wide range of structural and morphological characteristics, composition, and pH . The influence of sample size, diluent composition, and processing time on efficiency of recovery of Salmonella and other pathogens needs to be evaluated before a method(s) for processing samples of raw produce can be recommended.

Rev Saude Publica, 2001 Aug, 35(4), 380 - 4
{Identification and typing of Yersinia enterocolitica biotypes and serotypes isolated}; Castaneda PE et al.; OBJECTIVE: To assess the presence of Yersinia enterocolitica in otherwise healthy pigs slaughtered for human consumption . METHODS: One hundred pharyngeal tonsils were sampled in a slaughterhouse in the state of Mexico . The minimum sample size (n=100) was calculated based on a preliminary sample of 20 cases, which had 20% positive cases . The collected tonsil samples were inoculated in Rappaport broth, and Salmonella-Shigella and McConkey media . The biotyping identification process was based on biochemical and serological tests using O:3, O:8 and O:9 antisera . RESULTS: Twenty-two isolates were obtained . Most were biotype 1 (8 cases of O:3 and 8 cases of O:9), but 6 cases could not be serotyped . None of the isolates were of O:8 group . CONCLUSIONS: This was the first time that Y . enterocolitica serotypes were isolated from pig tonsils in Mexico . Its importance rely on the fact that the isolated serotypes are the most commonly found in public health problems.

Nucleic Acids Res, 2001 Oct 15, 29(20), 4195 - 205
Families of restriction enzymes: an analysis prompted by molecular and genetic data for type ID restriction and modification systems; Titheradge AJ et al.; Current genetic and molecular evidence places all the known type I restriction and modification systems of Escherichia coli and Salmonella enterica into one of four discrete families: type IA, IB, IC or ID . StySBLI is the founder member of the ID family . Similarities of coding sequences have identified restriction systems in E.coli and Klebsiella pneumoniae as probable members of the type ID family . We present complementation tests that confirm the allocation of EcoR9I and KpnAI to the ID family . An alignment of the amino acid sequences of the HsdS subunits of StySBLI and EcoR9I identify two variable regions, each predicted to be a target recognition domain (TRD) . Consistent with two TRDs, StySBLI was shown to recognise a bipartite target sequence, but one in which the adenine residues that are the substrates for methylation are separated by only 6 bp . Implications of family relationships are discussed and evidence is presented that extends the family affiliations identified in enteric bacteria to a wide range of other genera.

Antimicrob Agents Chemother, 2001 Nov, 45(11), 3059 - 64
Clearance of infection with Mycobacterium bovis BCG in mice is enhanced by treatment with S28463 (R-848), and its efficiency depends on expression of wild-type Nramp1 (resistance allele); Moisan J et al.; The mouse bcg host resistance gene is known to control the activation of host macrophages for killing of intracellular parasites like Leishmania donovani as well as intracellular bacteria, including Mycobacterium bovis BCG and Salmonella enterica serovar Typhimurium . The Nramp1 gene has been mapped to this locus and affects the efficiency of macrophage activation . It has been shown that imidazoquinoline compounds, including S28463, are able to improve the clearance of a number of intracellular pathogens such as herpes simplex virus 2, human papillomavirus, and Leishmania . The goal of this study was to determine whether S28463 is efficient against infection with another intracellular pathogen, M . bovis BCG, and to determine the molecular basis underlying this effect . To achieve this, B10A.Nramp1(r) and B10A.Nramp1(-/-) mice were infected with M . bovis BCG and treated with S28463 . The bacterial content in the spleen from these mice was assayed by a colony-forming assay . In addition, in vitro experiments were performed using bone marrow-derived macrophage cell lines from these mice . These cells were treated with S28463 and/or gamma interferon (IFN-gamma), and nitric oxide (NO) production was measured . Our study was able to show that S28463 acts in synergy with IFN-gamma to increase the production of NO in vitro . We were also able to demonstrate that mice that carried the resistant allele of the Nramp1 gene and were infected with M . bovis BCG responded to treatment with S28463, resulting in a decreased bacterial load after 2 weeks of treatment . Mice that do not express the Nramp1 gene responded only to a very large dose of S28463, and the response was not as efficient as that observed in mice carrying a wild-type Nramp1 allele . Our data provide evidence for the potential of S28463 as an immunomodulator that may be helpful in designing efficient strategies to improve host defense against mycobacterial infection.

J Reprod Immunol, 2001 Oct-Nov, 52(1-2), 61 - 75
Induction of specific immune responses in the genital tract of women after oral or rectal immunization and rectal boosting with Salmonella typhi Ty 21a vaccine; Kutteh WH et al.; The purpose of this study was to determine the efficacy of intestinal tract immunization in the induction of specific antibodies in human female genital tract secretions . Live attenuated typhoid vaccine Ty 21a was administered to three groups of healthy female volunteers, who were not using hormonal contraceptives . Group 1 included 15 women vaccinated orally . Group 2 included seven of the same women, who were vaccinated rectally 6 months later . Group 3 included 11 volunteers, who were vaccinated rectally . Salmonella-specific antibodies of IgG and IgA were measured in vaginal lavage and cervical mucus after oral or rectal primary vaccination . Salmonella-specific antibodies measured 1 month after rectal booster vaccination demonstrated significant increases in vaginal fluids and cervical mucus and were dominated by IgA . These results indicate that specific antibodies in the human female genital tract induced by primary vaccination can be enhanced by subsequent rectal administration of vaccines.

Mutat Res, 2001 Nov 1, 483(1-2), 1 - 11
The DeltauvrB mutations in the Ames strains of Salmonella span 15 to 119 genes; Porwollik S et al.; The DeltauvrB mutations present in strains of Salmonella enterica Typhimurium used commonly in the Salmonella (Ames) mutagenicity assay were isolated independently for at least five different his mutants . These deletions all involved the galactose operon, biotin operon, nucleotide-excision-repair uvrB gene, and chlorate-resistance genes . Beyond this, the size of the deletions and the number and type of genes deleted have remained unknown for nearly 30 years . Here, we have used genomic hybridization to a Typhimurium microarray to characterize these five DeltauvrB deletions . The number of genes (and amount of DNA) deleted due to the DeltauvrB mutations are 15 (16kb) each in TA97 and TA104, 47 (50kb) in TA100, 87 (96kb) in TA1537, and 119 (125kb) in TA98, accounting for 0.3, 0.3, 1.0, 1.9, and 2.6% of the genome, respectively . In addition, TA97 and TA104 contain an identical three-gene deletion elsewhere in their genomes, and, most remarkably, TA104 contains a 282-gene amplification, representing 7% of the genome . Missing genes include mfdA and mdaA, encoding a multi-drug translocase and a major nitroreductase, respectively, both absent in TA98; dps, encoding a DNA-binding protein absent in TA1537 and TA98; and dinG, encoding a lexA-regulated repair enzyme, absent in three DeltauvrB lineages . Genes involved in molybdenum cofactor biosynthesis and a number of ORFs of unknown functions are missing in all DeltauvrB strains investigated . Studies in DeltauvrB strains of Escherichia coli have found that the enhanced mutagenesis of some base analogues was due to the deletion of genes involved in molybdenum cofactor biosynthesis rather than to deletion of uvrB . These discoveries do not diminish the value of the data generated in the Ames strains . However, absence of genes other than uvrB may account for the enhanced mutagenicity of some compounds in DeltauvrB Ames strains . In general, microarrays will be useful for characterizing the extent and nature of deletion and amplification mutations.

J Agric Food Chem, 2001 Oct, 49(10), 5000 - 4
Contributions of major components to the antimutagenic effect of Hsian-tsao (Mesona procumbens Hemsl.); Yen GC et al.; Our aim was to determine the antimutagenic activity of various solvent extracts from an herb Mesona procumbens Hemsl, normally called Hsian-tsao in China . We also investigated the relationships between the special components in the water extract of Hsian-tsao (WEHT) and the antimutagenic activity . It was found that the extracts at 0-0.6 mg/plate from three solvents (water, methanol, and ethyl acetate) exhibited a dose-dependent antimutagenic effect against benzo{a}pyrene {B(a)P} and 2-amino-3-methylimidazo(4,5-f)quinoline (IQ), both are indirect mutagens in Salmonella tester strains TA98 and TA100 . The WEHT from three different plantations revealed a similar inhibitory effect on the mutagenicity of IQ in TA 98 at 2.5-5.0 mg/plate . The inhibitory effect of WEHT on the mutagenicity of IQ correlates with their polyphenol and ascorbic acid contents but not with their chlorophyll contents . These findings suggest that the antimutagenicity activity of WEHT may be attributed mainly to their polyphenolic compounds and ascorbic acid.

J Med Microbiol, 2001 Oct, 50(10), 919 - 24
Association between cyclohexane resistance in Salmonella of different serovars and increased resistance to multiple antibiotics, disinfectants and dyes; Randall LP et al.; A panel of 388 salmonellas of animal and human origin, comprising 35 serotypes, was tested for resistance to cyclohexane and to a range of antibiotics, disinfectants and dyes . Cyclohexane resistance was detected in 41 isolates (10.6%): these comprised members of the serovars Binza (1 of 15), Dublin (1 of 24), Enteritidis (1 of 61), Fischerkietz (4 of 5), Livingstone (9 of 11), Montevideo (1 of 32), Newport (4 of 23), Saint-paul (1 of 3), Senftenberg (10 of 24) and Typhimurium (9 of 93) . Most (39 of 41) of the cyclohexane-resistant isolates were from poultry . Statistical analysis showed that the cyclohexane-resistant strains were significantly more resistant than the cyclohexane-susceptible strains to ampicillin, chloramphenicol, ciprofloxacin, erythromycin, nalidixic acid, tetracycline, trimethoprim, cetrimide and triclosan . The multiresistance patterns seen were typical of those caused by efflux pumps, such as AcrAB . The emergence of such resistance may play an important role in the overall antibiotic resistance picture of Salmonella, with particular effect on ciprofloxacin.

Infect Immun, 2001 Nov, 69(11), 7106 - 20
Three-dimensional tissue assemblies: novel models for the study of Salmonella enterica serovar Typhimurium pathogenesis; Nickerson CA et al.; The lack of readily available experimental systems has limited knowledge pertaining to the development of Salmonella-induced gastroenteritis and diarrheal disease in humans . We used a novel low-shear stress cell culture system developed at the National Aeronautics and Space Administration in conjunction with cultivation of three-dimensional (3-D) aggregates of human intestinal tissue to study the infectivity of Salmonella enterica serovar Typhimurium for human intestinal epithelium . Immunohistochemical characterization and microscopic analysis of 3-D aggregates of the human intestinal epithelial cell line Int-407 revealed that the 3-D cells more accurately modeled human in vivo differentiated tissues than did conventional monolayer cultures of the same cells . Results from infectivity studies showed that Salmonella established infection of the 3-D cells in a much different manner than that observed for monolayers . Following the same time course of infection with Salmonella, 3-D Int-407 cells displayed minimal loss of structural integrity compared to that of Int-407 monolayers . Furthermore, Salmonella exhibited significantly lower abilities to adhere to, invade, and induce apoptosis of 3-D Int-407 cells than it did for infected Int-407 monolayers . Analysis of cytokine expression profiles of 3-D Int-407 cells and monolayers following infection with Salmonella revealed significant differences in expression of interleukin 1alpha (IL-1alpha), IL-1beta, IL-6, IL-1Ra, and tumor necrosis factor alpha mRNAs between the two cultures . In addition, uninfected 3-D Int-407 cells constitutively expressed higher levels of transforming growth factor beta1 mRNA and prostaglandin E2 than did uninfected Int-407 monolayers . By more accurately modeling many aspects of human in vivo tissues, the 3-D intestinal cell model generated in this study offers a novel approach for studying microbial infectivity from the perspective of the host-pathogen interaction.

Infect Immun, 2001 Nov, 69(11), 6725 - 30
Salmonella DNA adenine methylase mutants confer cross-protective immunity; Heithoff DM et al.; Salmonella isolates that lack or overproduce DNA adenine methylase (Dam) elicited a cross-protective immune response to different Salmonella serovars . The protection afforded by the Salmonella enterica serovar Typhimurium Dam vaccine was greater than that elicited in mice that survived a virulent infection . S . enterica serovar Typhimurium Dam mutant strains exhibited enhanced sensitivity to mediators of innate immunity such as antimicrobial peptides, bile salts, and hydrogen peroxide . Also, S . enterica serovar Typhimurium Dam(-) vaccines were not immunosuppressive; unlike wild-type vaccines, they failed to induce increased nitric oxide levels and permitted a subsequent robust humoral response to diptheria toxoid antigen in infected mice . Dam mutant strains exhibited a low-grade persistence which, coupled with the nonimmunosuppression and the ectopic protein expression caused by altered levels of Dam, may provide an expanded source of potential antigens in vaccinated hosts.

Infect Immun, 2001 Nov, 69(11), 6670 - 5
HLA-B27 expression does not modulate intracellular Chlamydia trachomatis infection of cell lines; Young JL et al.; Chlamydia trachomatis is an obligate intracellular pathogen . Infection of susceptible individuals with this bacterium can trigger the development of reactive arthritis, an acute inflammation that is associated with the expression of the class I major histocompatibility antigen, HLA-B27 . Other facultative intracellular pathogens, such as Yersinia and Salmonella spp., are also known triggers of reactive arthritis . Previous studies report conflicting results concerning whether the presence of HLA-B27 modulates the infection of cells with these enteric pathogens . In the present study, we have examined whether the expression of HLA-B27 can influence the infection of cell lines with C . trachomatis and also whether the replication of these bacteria is altered in HLA-B27-expressing cell lines . To do this, we have used a sensitive flow cytometric approach . We fixed and permeabilized cells and used fluorescein isothiocyanate-conjugated monoclonal antibody specific for chlamydia lipopolysaccharide to detect intracellular bacteria . The staining pattern obtained closely resembled the intracellular life cycle of chlamydia, with the appearance of brightly staining cells correlating to the microscopic detection of mature inclusion bodies . Moreover, since the percentage of cells that stained with the antibody was proportional to the infectious inoculum used, we were able to use the technique to quantitate the number of infectious organisms recoverable from infected cell lines . An important component of our study was the use of heparin to prevent reinfection of cells and thus enable the infection to be followed from a discrete time point . Our results suggest that HLA-B27 influences neither the infection nor replication of C . trachomatis serovar L2 within cell lines . Consequently, the role of HLA-B27 in the pathogenesis of reactive arthritis may lie downstream of the invasion and replication stages of the triggering pathogenic infection.

Infect Immun, 2001 Nov, 69(11), 6604 - 11
Effect of attenuated Salmonella enterica serovar Typhimurium expressing a Streptococcus mutans antigen on secondary responses to the cloned protein; Jespersgaard C et al.; Attenuated Salmonella enterica serovar Typhimurium has been used for targeted delivery of recombinant antigens to gut- and nose-associated lymphoid tissues . Contradictory reports have described the effect of preexisting immunity to the antigen delivery vehicle . We decided to examine this discrepancy by studying the effect of immunizing mice by the intranasal (i.n.) route with Salmonella expressing an insoluble protein and to study the ability to augment recall responses by boosting with either Salmonella-expressed protein or purified soluble protein alone . The glucan-binding domain (GLU) of the enzyme glucosyltransferase (GTF), which is an important virulence factor of Streptococcus mutans, was recombinantly expressed in the insoluble phase in S . enterica serovar Typhimurium, and the immunogenicity of this construct was studied in mice . We examined the induction of primary immune responses by insoluble GLU polypeptide delivered in Salmonella at week 1 (groups 1 and 2) and recall responses after a week 15 boost with either Salmonella expressing GLU (group 1) or purified GLU polypeptide (groups 2 and 3) . Group 4 served as the control and received phosphate-buffered saline alone by the i.n . route . Significant anti-GLU serum immunoglobulin G (IgG) levels were seen in groups 1, 2, and 3 at week 18 (P < 0.001), i.e., 3 weeks after the booster immunization . Mice in group 2, who received Salmonella followed by GLU, had the highest GLU-specific IgG levels among all groups . The serum IgG levels persisted in all responding groups for at least 7 weeks after the boost (week 22) . The IgG2a/IgG1 subclass ratio of serum anti-GLU antibodies in group 1 significantly increased after the boost . These results support the induction of a type 1-like immune response to GLU after primary and booster immunizations with Salmonella expressing GLU . On the other hand, group 2 mice, which received Salmonella expressing GLU as the primary dose and soluble protein as the booster dose, exhibited a shift from a type 1-like to a more type 2-like immune response to GLU following the boost . These results indicate that S . enterica serovar Typhimurium is an excellent delivery vehicle for the insoluble and recombinantly expressed GLU of GTF and that this construct was especially effective in priming the host for a secondary response to soluble GLU polypeptide.

J Infect, 2001 Jul, 43(1), 17 - 8
Post-coronary artery bypass surgery pericardial abscess: Salmonella paratyphi B; Ahmed D et al.; Endemic enteric fever is one of the major health problems in South Asia where focal pyogenic infections with salmonella are being increasingly reported . A pericardial abscess following coronary artery bypass surgery with Salmonella paratyphi B was successfully treated, the first reported case so far .

J Bacteriol, 2001 Nov, 183(21), 6404 - 12
Structures of bacterial flagellar motors from two FliF-FliG gene fusion mutants; Thomas D et al.; Flagella purified from Salmonella enterica serovar Typhimurium contain FliG, FliM, and FliN, cytoplasmic proteins that are important in torque generation and switching, and FliF, a transmembrane structural protein . The motor portion of the flagellum (the basal body complex) has a cytoplasmic C ring and a transmembrane M ring . Incubation of purified basal bodies at pH 4.5 removed FliM and FliN but not FliG or FliF . These basal bodies lacked C rings but had intact M rings, suggesting that FliM and FliN are part of the C ring but not a detectable part of the M ring . Incubation of basal bodies at pH 2.5 removed FliG, FliM, and FliN but not FliF . These basal bodies lacked the C ring, and the cytoplasmic face of the M ring was altered, suggesting that FliG makes up at least part of the cytoplasmic face of the M ring . Further insights into FliG were obtained from cells expressing a fusion protein of FliF and FliG . Flagella from these mutants still rotated but cells were not chemotactic . One mutant is a full-length fusion of FliF and FliG; the second mutant has a deletion lacking the last 56 residues of FliF and the first 94 residues of FliG . In the former, C rings appeared complete, but a portion of the M ring was shifted to higher radius . The C-ring-M-ring interaction appeared to be altered . In basal bodies with the fusion-deletion protein, the C ring was smaller in diameter, and one of its domains occupied space vacated by missing portions of FliF and FliG.

J Bacteriol, 2001 Nov, 183(21), 6244 - 52
Formation of intermediate transcription initiation complexes at pfliD and pflgM by sigma(28) RNA polymerase; Givens JR et al.; The sigma subunit of prokaryotic RNA polymerase is an important factor in the control of transcription initiation . Primary sigma factors are essential for growth, while alternative sigma factors are activated in response to various stimuli . Expression of class 3 genes during flagellum biosynthesis in Salmonella enterica serovar Typhimurium is dependent on the alternative sigma factor sigma(28) . Previously, a novel mechanism of transcription initiation at the fliC promoter by sigma(28) holoenzyme was proposed . Here, we have characterized the mechanism of transcription initiation by a holoenzyme carrying sigma(28) at the fliD and flgM promoters to determine if the mechanism of initiation observed at pfliC is a general phenomenon for all sigma(28)-dependent promoters . Temperature-dependent footprinting demonstrated that promoter binding properties and low-temperature open complex formation are similar for pfliC, pfliD, and pflgM . However, certain aspects of DNA strand separation and complex stability are promoter dependent . Open complexes form in a concerted manner at pflgM, while a sequential pattern of open complex formation occurs at pfliD . Open and initiated complexes formed by holoenzyme carrying sigma(28) are generally unstable to heparin challenge, with the exception of initiated complexes at pflgM, which are stable in the presence of nucleoside triphosphates.

J Bacteriol, 2001 Nov, 183(21), 6184 - 96
Comparison of DeltarelA strains of Escherichia coli and Salmonella enterica serovar Typhimurium suggests a role for ppGpp in attenuation regulation of branched-chain amino acid biosynthesis; Tedin K et al.; The growth recovery of Escherichia coli K-12 and Salmonella enterica serovar Typhimurium DeltarelA mutants were compared after nutritional downshifts requiring derepression of the branched-chain amino acid pathways . Because wild-type E . coli K-12 and S . enterica serovar Typhimurium LT2 strains are defective in the expression of the genes encoding the branch point acetohydroxy acid synthetase II (ilvGM) and III (ilvIH) isozymes, respectively, DeltarelA derivatives corrected for these mutations were also examined . Results indicate that reduced expression of the known global regulatory factors involved in branched-chain amino acid biosynthesis cannot completely explain the observed growth recovery defects of the DeltarelA strains . In the E . coli K-12 MG1655 DeltarelA background, correction of the preexisting rph-1 allele which causes pyrimidine limitations resulted in complete loss of growth recovery . S . enterica serovar Typhimurium LT2 DeltarelA strains were fully complemented by elevated basal ppGpp levels in an S . enterica serovar Typhimurium LT2 DeltarelA spoT1 mutant or in a strain harboring an RNA polymerase mutation conferring a reduced RNA chain elongation rate . The results are best explained by a dependence on the basal levels of ppGpp, which are determined by relA-dependent changes in tRNA synthesis resulting from amino acid starvations . Expression of the branched-chain amino acid operons is suggested to require changes in the RNA chain elongation rate of the RNA polymerase, which can be achieved either by elevation of the basal ppGpp levels or, in the case of the E . coli K-12 MG1655 strain, through pyrimidine limitations which partially compensate for reduced ppGpp levels . Roles for ppGpp in branched-chain amino acid biosynthesis are discussed in terms of effects on the synthesis of known global regulatory proteins and current models for the control of global RNA synthesis by ppGpp.

Vet Immunol Immunopathol, 2001 Oct, 82(3-4), 257 - 72
Cytokine gene expression in lymph node and spleen of sheep in response to Salmonella infection by two serotypes displaying different host specificity; Montagne A et al.; In order to investigate the determinism of the host specificity and to better understand the host resistance mechanisms, infections of sheep were performed with either S . abortusovis, serotype specific for ovine species, or with S . dublin, serotype adapted to cattle and accidentally transmissible to human . Following a subcutaneous challenge, S . dublin disseminated more rapidly towards lymphoid tissues than S . abortusovis . However, S . abortusovis tended to persist in spleen more efficiently than S . dublin . Using a quantitative RT-PCR method, the expression level of ovine cytokines genes was measured in the draining lymph node and in the spleen, in the course of infection . Inflammatory cytokine response was characterised by an early and strong increase of IL-1beta and TNFalpha mRNA in both lymphoid organs following S . dublin infection, while S . abortusovis challenge only induced IL-1beta mRNA increase in the spleen at day 3 post-inoculation . Likewise, S . dublin infection provoked a marked increase of IL-12 mRNA and a slight up-regulation of IFNgamma gene transcription in the local lymphoid site, in contrast to S . abortusovis infection . Elsewhere, both serotypes induced a strong and early IL-10 mRNA production and had no effect on IL-4 gene expression . Finally, taken together, these data suggest that the intensity of inflammatory and anti-infectious cytokine responses, but not the type 2 cytokine response, is serotype-dependent . They also suggest that the host-specific serotype, by limiting the host cytokine-mediated defence, could favour its persistence within lymphoid organs.

Gastroenterol Clin North Am, 2001 Sep, 30(3), 625 - 35
Infectious diarrhea in the elderly; Slotwiner-Nie PK et al.; Infectious diarrhea is an important disease in the elderly . Some basic principles have been outlined, as follows . In the elderly: Infectious diarrhea is an underappreciated health problem . There is a higher mortality rate and case-fatality rate compared with younger persons . Infectious diarrhea is most often associated with group settings (e.g., nursing homes and skilled nursing facilities) or antibiotic use . Infectious diarrhea may be associated with abnormal immune function (i.e., immunosenescence) . Certain bacterial infections are commoner (e.g., C . difficile, E . coli O157:H7, and Salmonella) . Some infections behave differently (e.g., Salmonella) . Prompt and adequate rehydration measures are crucial . The institution of appropriate contact isolation and infection control measures is crucial in group settings.

Arch Pediatr, 2001 Sep, 8 Suppl 4, 732s - 741s
{Severe infections in children with sickle cell disease: clinical aspects and prevention}; Begue P et al.; Sickle-cell disease (SCD) is associated with frequent and often severe infections as a result of immune function impairment and functional asplenia . Also, infection can trigger a vasoocclusive crisis . Pneumonococcal bacteremia and meningitis due to S . pneumoniae are often lethal and justify the penicillin prophylaxis, which has provided a dramatic decrease in early mortality bacterial pneumonia is common in patients younger than four years, with most cases being due to S . pneumoniae, H . influenzae, Mycoplasma pneumoniae, Chlamydia pneumoniae . Acute chest syndrome is both a difficult differential diagnosis and a common concomitant of bacterial pneumonia, because they are often intricated . Osteomyelitis is generally due to Salmonella, most often S . enteritidis . Multiple foci are common and treatment is difficult, with some patients developing chronic osteomyelitis with sequestration . Osteomyelitis is less frequent in developed countries and must been differentiated with bone infarction by use of bone scintigraphy . Parvovirus B19 infection causes acute erythroblastopenias . Malaria does not result in cerebral malaria, but can lead to severe anaemia or vasoocclusive crisis, and should therefore be effectively prevented . Antimicrobials are generally selected for efficacy against pneumococci (septicemia, meningitis), Salmonella (osteomyelitis, meningitis), and M . pneumoniae (pneumonia) . Prophylactic therapy is of paramount importance and relies on long-term or lifelong penicillin therapy started at three months of age and no closely-spaced immunizations, most notably against peumococci, hepatitis B virus, S . typhi and H . influenzae . Resistant pneumococcal strains have not been reported to cause prophylactic treatment failures . New conjugated pneumococcal vaccines are effective in protecting very young infants and should therefore be used in sickle cell patients.

J Mol Biol, 2001 Oct 5, 312(5), 1027 - 36
Proteolytic analysis of the FliH/FliI complex, the ATPase component of the type III flagellar export apparatus of Salmonella; Minamino T et al.; The ATPase FliI of the Salmonella type III flagellar protein export apparatus is a 456 amino acid residue cytoplasmic protein consisting of two regions, an N-terminal flagellum-specific region and a C-terminal ATPase region . It forms a complex with a regulatory protein FliH in the cytoplasm . Multi-angle light-scattering studies indicate that FliH forms a homodimer, (FliH)2, and that FliH and FliI together form a heterotrimer, (FliH)2FliI . Mobility upon gel-filtration chromatography gives much higher apparent molecular masses for both species, whereas the mobility of FliI is normal . Sedimentation velocity measurements indicate that both (FliH)2 and the FliH/FliI complex are quite elongated . We have analyzed FliH, FliI and the FliH/FliI complex for proteolytic sensitivity . FliI was degraded by clostripain into two stable fragments, one of 48 kDa (FliI(CL48), missing the first seven amino acid residues) and the other of 46 kDa (FliI(CL46), missing the first 26 residues) . Small amounts of two closely spaced 38 kDa fragments (FliI(CL38), missing the first 93 and 97 residues, respectively) were also detected . The FliH homodimer was insensitive to clostripain proteolysis and provided protection to FliI within the FliH/FliI complex . Neither FliI(CL48) nor FliI(CL46) could form a complex with FliH, demonstrating that the N terminus of FliI is essential for the interaction . ATP, AMP-PNP, and ADP bound forms of FliI within the FliH/FliI complex regained sensitivity to clostripain cleavage . Also, the sensitivity of the two FliI(CL38) cleavage sites was much greater in the ATP and AMP-PNP bound forms than in either the ADP bound form or nucleotide-free FliI . The ATPase domain itself was insensitive to clostripain cleavage . We suggest that the N-terminal flagellum-specific region of FliI is flexible and changes its conformation during the ATP hydrolysis cycle .

Clin Immunol, 2001 Oct, 101(1), 32 - 7
Bacteremia associated with live attenuated chi8110 Salmonella enterica serovar Typhi ISP1820 in healthy adult volunteers; Frey SE et al.; Live attenuated chi8110 Salmonella enterica serovar Typhi ISP1820 vaccine was given in a dose-escalation trial to healthy, adult volunteers . Positive stool and blood cultures were noted, but limited, as were immune responses measured by ELISA and ELISPOT . Only volunteers with bacteremia developed immune responses; however, no symptoms were associated with bacteremia . The vaccine was insufficiently immunogenic for use as a vaccine . It is possible that reduced survival in the gut and reduced immunogenicity may have been due to the thawing of frozen inocula immediately prior to use .

Microbiology, 2001 Oct, 147(Pt 10), 2697 - 704
Porins from Salmonella enterica serovar Typhimurium induce TNF-alpha, IL-6 and IL-8 release by CD14-independent and CD11a/CD18-dependent mechanisms; Galdiero M et al.; Lipopolysaccharide (LPS) of Gram-negative bacteria and several surface components of Gram-positive bacteria utilize CD14 and CD11a/18 as cellular receptors to induce expression and release of cytokines . Of the surface components of Gram-negative bacteria, porins exhibit a biological activity similar to that of LPS . The results in this paper show that the mechanism of stimulation by porins of THP-1 cells enriched in CD14 receptor after treatment with 1,25-dihydroxyvitamin D(3) (vitamin D(3)) is independent of this receptor, but is partially dependent on CD11a/18 integrins.

J Appl Microbiol, 2001 Oct, 91(4), 750 - 8
Persistence of Escherichia coli, Salmonella choleraesuis, Aujeszky's Disease virus and Blue Eye Disease virus in ensilages based on the solid fraction of pig faeces; Martinez-Gamba R et al.; AIMS: This study was carried out to determine the survival time of Escherichia coli, Salmonella choleraesuis, Aujeszky's Disease virus and Blue Eye Disease virus in ensilages based on the solid fraction of pig faeces . METHODS AND RESULTS: The four micro-organisms were inoculated into microsilos based on the solid fraction of pig faeces, sorghum and molasses . They were left for 0, 7, 14, 28 and 56 days, after which the state of each microsilo was evaluated, and isolation of the inoculated agents was attempted . The four inoculated agents were isolated only on day 0 of ensilage . The viral agents were identified through the cytopathic effect and fluorescence . CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: It is concluded that ensilages based on the solid fraction of pig faeces appear to reduce the risk of the transmission of the agents inoculated in this study and help to reduce the environmental impact by using the solid in animal feed.

J Appl Microbiol, 2001 Oct, 91(4), 715 - 24
Temperature shock, injury and transient sensitivity to nisin in Gram negatives; Boziaris IS et al.; AIMS: The effect of thermal stresses on survival, injury and nisin sensitivity was investigated in Salmonella Enteritidis PT4, PT7 and Pseudomonas aeruginosa . METHODS AND RESULTS: Heating at 55 degrees C, rapid chilling to 0.5 degrees C or freezing at -20 degrees C produced transient sensitivity to nisin . Cells were only sensitive if nisin was present during stress . Resistance recovered rapidly afterwards, though some cells displayed residual injury . Injury was assessed by SDS sensitivity, hydrophobicity changes, lipopolysaccharide release and NPN uptake . LPS release and hydrophobicity were not always associated with transient nisin sensitivity . Uptake of NPN correlated better but persisted longer after treatment . CONCLUSIONS: Thermal shocks produce transient injury to the outer membrane, allowing nisin access . After treatment, the permeability barrier is rapidly restored by a process apparently involving reorganization rather than biosynthetic repair . SIGNIFICANCE AND IMPACT OF THE STUDY: Inclusion of nisin during food treatments that impose sub-lethal stress on Gram negatives could increase process lethality, enhancing microbiological safety and stability.

J Clin Microbiol, 2001 Oct, 39(10), 3609 - 16
Molecular typing of Salmonella serotypes prevalent in animals in England: assessment of methodology; Liebana E et al.; Salmonella enterica serotypes Derby, Mbandaka, Montevideo, Livingstone, and Senftenberg were among the 10 most prevalent serotypes isolated from farm animals in England and Wales in 1999 . These serotypes are of potential zoonotic relevance; however, there is currently no "gold standard" fingerprinting method for them . A collection of isolates representing the former serotypes and serotype Gold Coast were analyzed using plasmid profiling, pulsed-field gel electrophoresis (PFGE), and ribotyping . The success of the molecular methods in identifying DNA polymorphisms was different for each serotype . Plasmid profiling was particularly useful for serotype Derby isolates, and it also provided a good level of discrimination for serotype Senftenberg . For most serotypes, we observed a number of nontypeable plasmid-free strains, which represents a limitation of this technique . Fingerprinting of genomic DNA by ribotyping and PFGE produced a significant variation in results, depending on the serotype of the strain . Both PstI/SphI ribotyping and XbaI-PFGE provided a similar degree of strain differentiation for serotype Derby and serotype Senftenberg, only marginally lower than that achieved by plasmid profiling . Ribotyping was less sensitive than PFGE when applied to serotype Mbandaka or serotype Montevideo . Serotype Gold Coast isolates were found to be nontypeable by XbaI-PFGE, and a significant proportion of them were found to be plasmid free . A similar situation applies to a number of serotype Livingstone isolates which were nontypeable by plasmid profiling and/or PFGE . In summary, the serotype of the isolates has a considerable influence in deciding the best typing strategy; a single method cannot be relied upon for discriminating between strains, and a combination of typing methods allows further discrimination.

J Clin Microbiol, 2001 Oct, 39(10), 3583 - 5
Rapid identification and antibiotic susceptibility testing of Salmonella enterica serovar Typhi isolated from blood: implications for therapy; Saha SK et al.; The turnaround time (TAT) for Salmonella enterica serovar Typhi identification and reporting of the antibiotic susceptibility profile was determined for 391 cases of typhoid fever, using the lysis direct plating or lysis centrifugation method of blood culture along with rapid antimicrobial susceptibility testing . The TAT was more rapid (TAT for 90% of the patients {TAT(90)} = 30 h; TAT(100) </= 67 h) than was possible with conventional methodologies and was equivalent to that reported previously using more advanced, costly technologies that are largely unavailable in developing countries . Antibiotic susceptibility profiles, determined by the rapid antimicrobial susceptibility testing method, of randomly selected 60 S . enterica serovar Typhi isolates were identical to those determined by overnight conventional testing . Preliminary assessment of the impact of the reduced TAT on physician practices revealed that initial empirical therapy was prescribed at the time of presentation in most cases (87 of 108 {81%}) despite awareness that the final report would be available on the following day . Patients treated empirically with first-line antibiotics and shown subsequently to be infected with a multidrug-resistant strain benefited most (8 cases), since therapy was changed appropriately on the following day . In an additional 21 cases, therapy with an appropriate antibiotic was initiated after culture results were available . Thus, in approximately one-fourth (29 of 108 {27%}) of the cases, a change in management to an agent active for treatment of the isolate was made after receipt of the test results . However, in no case was therapy changed from a second-line to a first-line agent, even if the isolate was reported on the day after presentation to be sensitive to first-line therapy (33 cases) . Ways in which to utilize rapid-TAT result reporting in order to positively influence physicians' prescribing in Bangladesh are the subject of ongoing research.

J Clin Microbiol, 2001 Oct, 39(10), 3461 - 5
Multistate outbreak of Salmonella serovar Muenchen infections associated with alfalfa sprouts grown from seeds pretreated with calcium hypochlorite; Proctor ME et al.; During September 1999, a multistate outbreak of Salmonella serovar Muenchen infection associated with eating raw alfalfa sprouts was identified in Wisconsin . Despite use of a calcium hypochlorite sanitizing procedure to pretreat seeds before sprouting, at least 157 outbreak-related illnesses were identified in seven states having sprouters who received alfalfa seed from a specific lot . The continued occurrence of sprout-related outbreaks despite presprouting disinfection supports the concern that no available treatment will eliminate pathogens from seeds before sprouting and reinforces the need for additional safeguards to protect the public . A lack of consumer knowledge regarding exposure to sprouts documented in this investigation suggests that more-targeted outreach to high-risk individuals may be needed to reduce their risk.

J Clin Microbiol, 2001 Oct, 39(10), 3452 - 60
Molecular analysis of a hospital cafeteria-associated salmonellosis outbreak using modified repetitive element PCR fingerprinting; Johnson JR et al.; A hospital cafeteria-associated outbreak of gastroenteritis due to Salmonella enterica serotype Infantis was retrospectively evaluated using modified repetitive element PCR (rep-PCR) fingerprinting with the ERIC2 and BOXA1R primers and computer-assisted gel analysis and dendrogram construction . Rep-PCR yielded objective between-cycler, same-strain similarity values of from 92% (composite fingerprints) to 96% (ERIC2 fingerprints) . The 70 Salmonella isolates (which included 19 serotype Infantis isolates from the hospital outbreak, 10 other serotype Infantis isolates, and 41 isolates representing 14 other serotypes) were resolved well to the serotype level with each of the three fingerprint types (ERIC2, BOXA1R, and composite) . Rep-PCR typing uncovered several historical serotyping errors and provided presumptive serotype assignments for other isolates with incomplete or undetermined serotypes . Analysis of replicate fingerprints for each isolate, as generated on two different thermal cyclers, indicated that most of the seeming subserotype discrimination noted in single-cycler dendrograms actually represented assay variability, since it was not reproducible in combined-cycler dendrograms . Rep-PCR typing, which would have been able to identify the presence of the hospital-associated serotype Infantis outbreak after the second outbreak isolate, could be used as a simple surrogate for serotyping by clinical microbiology laboratories that are equipped for diagnostic PCR.

Bull Soc Sci Med Grand Duche Luxemb, 2001, (1), 47 - 55
{Salmonella infections in swine . Salmonella infections in swine in meat hygiene}; Schoos J; Salmonella is considered one of the most important food borne pathogens that has potential implications for human health . In Germany, Salmonella monitoring is being used in swine farms as a predictor for Salmonella infection and to implement control measures directed to minimise cross-contamination at the slaughter plant . An research project was established in order to gain experience with the eradication of Salmonella in German swine herds.

Berl Munch Tierarztl Wochenschr, 2001 Sep-Oct, 114(9-10), 404 - 8
Sequence polymorphism of the Salmonella plasmid virulence factor D (SpvD) in Salmonella enterica isolates of animal origin; Bauerfeind R et al.; The nucleotide sequence encoding the Salmonella plasmid virulence factor D (SpvD) was determined in 17 Salmonella strains that were different in O and H antigen patterns, animal host and geographical origin, and year of isolation . Nucleotide sequence comparison revealed the existence of at least nine spvD alleles resulting in 8 SpvD protein variants although the nucleotide sequences were highly similar (identity 98.8-100%) . The spvD gene products differed from each other in up to 4 amino acid residues only with the exception of the carboxy-terminally truncated SpvD variant of one S . Gallinarum field isolate . The highly conserved primary structure of SpvD in epidemiologically relevant salmonellae suggests that this virulence factor is a promising antigen candidate for diagnostic purposes (i.e . antibody detection in infected animals) but also for immunoprophylaxis in farm animal species.

Berl Munch Tierarztl Wochenschr, 2001 Sep-Oct, 114(9-10), 397 - 400
Identification of patterns of transmission of Salmonella within swine production systems using pulsed field gel electrophoresis (PFGE) and repetitive sequence polymerase chain reaction (REP-PCR): a quantitative analysis; Weigel RM et al.; Pulsed field gel electrophoresis (PFGE) using 3 enzymes (Spe I, Xba I, Avr II) and repetitive sequence polymerase chain reaction (REP-PCR) with 3 primers (BOX, ERIC, REP) were compared with respect to their validity as a method for identifying transmission of Salmonella on swine farms . Sixty-eight isolates of Salmonella were obtained from feces of swine, cats, mice, and birds, insect body parts, water and floor samples, and boot scrapings collected on 9 swine farms in Illinois USA . Genetic distances between isolates were calculated using the Dice matching coefficient . Cluster analysis of distance matrices was conducted using the UPG-MA algorithm . There was no significant difference between PFGE and REP-PCR in the genetic diversity detected; however, REP-PCR differentiated between 14 pairs of isolates which PFGE identified as identical . There were no significant differences between PFGE and REP-PCR in identifying all or most close genetic links as isolates from the same farm, the same building, and from the same sampling visit, suggesting ecological validity for both methods . Thus, REP-PCR should be considered as an acceptable and perhaps preferable alternative to PFGE as a genotyping method for studies of Salmonella transmission.

Berl Munch Tierarztl Wochenschr, 2001 Sep-Oct, 114(9-10), 389 - 92
First international ring trial of ELISAs for Salmonella-antibody detection in swine; van der Heijden HM; An international ring trial for Salmonella-ELISAs for swine serology was organized . Twelve laboratories participated and used "in-house" ELISAs or commercially available kits . In total 47 well-defined sera from various sources, including inoculation studies with Salmonella-strains from sero-groups B, C1, C2, D, and E1, were tested blindfold . The specificity of most ELISAs was satisfactory, but relatively large differences were found between the sensitivities of the tests . It is concluded that international reference samples should be made available to guarantee a minimum level of sensitivity.

Berl Munch Tierarztl Wochenschr, 2001 Sep-Oct, 114(9-10), 356 - 9
Epidemiological investigations into the sources of Salmonella contamination of pork; Swanenburg M et al.; This study was conducted to elucidate which phases of the pork production chain contribute to the Salmonella contamination on pork after slaughter . During 7 sampling days, samples were collected of randomly selected slaughter pigs and of pigs from selected Salmonella-infected and Salmonella-free herds, trucks, lairages, and slaughterlines, in two slaughterhouses . Salmonella genotypes, present on pork after slaughter, were compared with Salmonella types, present on the farm, in the truck, in the lairage, on slaughter equipment, and in pigs from other herds . Results showed that the slaughterline was the most important source of Salmonella contamination of carcasses . The farm was the most important source of contamination of livers, tongues, rectal samples and mesenterial lymphnodes, for pigs originating from sero-positive herds . The lairage was the most important contamination source for pigs originating from sero-negative herds, for all samples, except carcasses . It is recommended to avoid each direct or indirect contact between different herds along the whole pork production chain, especially between Salmonella-infected and Salmonella-free herds.

Berl Munch Tierarztl Wochenschr, 2001 Sep-Oct, 114(9-10), 346 - 9
Trends and seasonal variations in the occurrence of Salmonella in pigs, pork and humans in Denmark, 1995-2000; Hald T et al.; A mandatory programme monitoring the occurrence of Salmonella in pork at slaughterhouses and a serological monitoring of slaughter-pig herds has been implemented in Denmark since 1993 and 1995, respectively . All results are stored in a central database . From this, aggregated weekly results of serological and bacteriological samples collected in the period between January 1995 and July 2000 were extracted . In addition, the reported weekly incidence of human infections with S . Typhimurium covering the same time period was obtained . The times series were analysed for trends and cyclic variations by seasonal decomposition . The association between the incidence in humans and the prevalence of Salmonella in pigs and pork, and prevailing weather conditions, were analysed by using a general linear (glm) and a general additive model (gam) . Explanatory variables were lagged to account for time elapsed between sampling, consumption, incubation period and case registration . The results of the seasonal decomposition showed an overall declining trend in all three time series . All time series exhibited a double peaked annual cycle . The seasonal variation of the prevalence in pork and the human incidence had a very similar course . The variables that were both biologically meaningful and statistically significant in both regression models were the prevalence in pork sampled 4 to 5 weeks before case registration, the seroprevalence, measured as the average prevalence of week 15 to 35 before case registration, and the air temperature lagged at 2 and 3 weeks . Limitations on inferences from overall surveillance data are discussed.

Berl Munch Tierarztl Wochenschr, 2001 Sep-Oct, 114(9-10), 339 - 41
Evaluation of cross-protection afforded by a Salmonella Choleraesuis vaccine against Salmonella infections in pigs under field conditions; Maes D et al.; This field study investigated the efficacy of a Salmonella Choleraesuis live vaccine (Argus SC) to reduce the number of infections with Salmonella . Twelve groups of about 380 pigs each were randomly allocated to either vaccination (V) or no vaccination (C) . The vaccine was applied orally at 3 and 16 weeks . Forty pigs per group were blood sampled at 3, 10, 16, and 24 weeks to detect possible antibodies against Salmonella . The prevalence of Salmonella in the lymph nodes was the major variable . In the V groups, only 0.6% of the lymph nodes were positive, whereas 7.2% were positive in the C groups (p < 0.001) . The percentage of seropositive pigs at 24 weeks (cut-off OD > 10) was 26% and 9% in the V and C groups, respectively (p < 0.001) . The present study documented that vaccination with a live modified S . Choleraesuis vaccine is a useful tool to lower the prevalence of Salmonella in swine herds.

Berl Munch Tierarztl Wochenschr, 2001 Sep-Oct, 114(9-10), 331 - 4
Eradication of Salmonella Yoruba in an integrated pig herd; Osterberg J et al.; An integrated SPF herd with 320 sows was found infected with Salmonella Yoruba during an annual control among sows, aiming to verify freedom from Salmonella infections . It is believed that the infection was introduced to the herd by purchase of feed . The herd performed an age segregated rearing system . Sows and piglets were reared at a central farm, while growers (25-100 kg body weight) were reared at sub-estates . The growers were free from the infection, and as a consequence a specially designed eradication program was designed . Farrowing and weaning were defined as periods of risk for sows and piglets, respectively . Consequently sows were isolated and individually tested for presence of Salmonella one week before and one week after farrowing . The offspring were tested one week post weaning . To verify freedom from disease among piglets they were also tested another time before transfer to the uninfected sub-estates . Piglets with undefined status regarding Salmonella were denoted animals at risk and not transferred to the sub-estates . Instead they were transferred to a third estate, rented to house pigs at risk . The program was successful . It allowed full production during performance, and the herd was declared free from S . Yoruba seven and a half months after the initial diagnosis.

Zh Mikrobiol Epidemiol Immunobiol, 2001 Jul-Aug, (4), 67 - 74
{Bacterial pathogenicity islands}; Bondarenko VM; The information on the key pathogenicity factors of uropathogenic and enteropathogenic Escherichia coli, Shigella, Salmonella, Vibrio cholerae, Yersinia, Listeria and Helicobacter pylori is reviewed . The analysis of data on pathogenicity "islands" and "islets" of infective agents is given . The problems of the genetic control of pathogenicity factors and the functions of pathogenicity "islands", found in infective agents, are discussed.

Zh Mikrobiol Epidemiol Immunobiol, 2001 Jul-Aug, (4), 117 - 9
{Characteristics of urogenital and post-enterocolitis reactive arthritides}; Burmistrova AL et al.; The immune status and profile of HLA antigens of loci A and B were evaluated in 159 patients with reactive arthritis . Reactive arthritis was caused by urogenital chlamydial infection in 64.2% of cases and by Shigella, Salmonella and Yersinia enterocolitica infection in 18.9% of cases . In patients with different etiology of the disease some variations in its course and outcome, immune status as well as in the HLA antigen profile were established that is indicative of genetic determination of the immune response character . The established specific variations in the immune and immunogenetic status of patients with reactive arthritis of different etiology may be used for improving diagnosis and treatment efficacy.

J Bacteriol, 2001 Oct, 183(20), 6036 - 45
SseBCD proteins are secreted by the type III secretion system of Salmonella pathogenicity island 2 and function as a translocon; Nikolaus T et al.; The type III secretion system encoded by Salmonella pathogenicity island 2 (SPI2) is required for systemic infections and intracellular accumulation of Salmonella enterica . This system is induced by intracellular Salmonella and subsequently transfers effector proteins into the host cell . Growth conditions either inducing expression of the type III secretion system or the secretion of substrate proteins were defined . Here we report the identification of a set of substrate proteins consisting of SseB, SseC, and SseD that are secreted by the SPI2 system in vitro . Secretion was observed if bacterial cells were exposed to acidic pH after growth in minimal medium with limitation of Mg(2+) or phosphate . SseB, -C, and -D were isolated in a fraction detached from the bacterial cell surface by mechanical shearing, indicating that these proteins are predominantly assembled into complexes on the bacterial cell surface . The three proteins were required for the translocation of SPI2 effector proteins SspH1 and SspH2 into infected host cells . Thus, SseB, SseC, and SseD function as the translocon for effector proteins by intracellular Salmonella.

Biochemistry (Mosc), 2001 Aug, 66(8), 885 - 93
Antioxidant properties, autooxidation, and mutagenic activity of echinochrome a compared with its etherified derivative; Lebedev AV et al.; Antioxidant properties of 2,3,5,7,8-pentahydroxy-6-ethyl-1,4-naphthoquinone (echinochrome A) were linked with the scavenging of peroxy radicals in liposomes, trapping of superoxide anion radicals, and binding of ferrous ions to inactive complexes in the aqueous phase . The antioxidant property of 6-ethyl-2,3,7-trimethoxy-5,8-dihydroxy-1,4-naphthoquinone (trimethoxyechinochrome A) was negligible . Autooxidation of echinochrome A was increased in basic media according to the degree of its dissociation . Autooxidation of polyvalent anions in basic media was accompanied by generation of naphthosemiquinone and superoxide anion radicals as free radical intermediates . An increased rate of echinochrome A autooxidation was noted in the presence of calcium ions . This was explained by a shift of pK of Ca2+-echinochrome A complexes toward acidic pH comparably with echinochrome A . Echinochrome A possessed pronounced mutagenic activity, while trimethoxyechinochrome A was inactive in the Salmonella/mammalian microsome reverse mutation assay (Ames test) for all examined cells (TA98, TA100, TA1537) . Comparison of the chemical and biological activity of echinochrome A and trimethoxyechinochrome A demonstrated the key role of the beta-hydroxyl groups in the 2nd, 3rd, and 7th naphthol cycle positions . The O2-* and naphthosemiquinone radicals generated in the redox transition of 2,3-oxygroups may be the reason for the strongly pronounced mutagenicity of echinochrome A.

Curr Rheumatol Rep, 2001 Oct, 3(5), 412 - 8
Pathogenesis of reactive arthritis; Sieper J; There is good evidence that bacteria persist in vivo in patients with reactive arthritis (ReA) . While Chlamydia seem to hide inside the joint, other areas such as gut mucosa or lymph nodes seem to be more likely places for Salmonella and Yersinia . T-helper (Th) 1 cells secreting cytokines such as IFN gamma and TNF alpha are crucial for an effective elimination of these bacteria . An inhibited Th1-response could be demonstrated in ReA, probably contributing to bacterial persistence . While HLA-B27 is found in only approximately 50% of patients with acute ReA, HLA-B27 seems to be crucial for the development of features typical with chronic spondyloarthropathy, such as sacroiliitis . Among several hypotheses to explain the interaction of bacteria with HLA-B27, the most likely seems to be that until now unknown bacterial or self- antigens were presented by HLA-B27 to CD8(+) T-cells . An important site where the immunopathology takes place seems to be at the insertion of tendons and ligaments at bone . Because antibiotics have failed so far in the treatment of ReA immunomodulatory therapies, based on a better understanding of the pathogenesis, alone or in combination with antibiotics might be an option for the future.

J Food Prot, 2001 Sep, 64(9), 1309 - 14
Destruction of Escherichia coli O157:H7 and Salmonella enteritidis in cow manure composting; Lung AJ et al.; Application of cow manure and composted manure in agricultural practice could potentially cause contamination of foodstuffs with pathogenic bacteria such as Salmonella Enteritidis and Escherichia coli O157:H7 . In this study, rifampicin-resistant (RifR) E . coli O157:H7 and Salmonella Enteritidis at a level of 7 log CFU/g of raw compost feed were used to determine the effect of a bench-scale composting system on their survival . RifR E . coli O157:H7 was not detected after 72 h of composting at 45 degrees C, and RifR Salmonella Enteritidis was not detected after 48 h . The use of selective media for enrichment failed to recover in the composting samples held at 45 degrees C for 96 h . However, the pathogens showed no change in bacterial numbers when the composting system was held at room temperature . Thus, properly composted manure can be safely used in food crop production while minimizing the likelihood of microbial contamination.

J Food Prot, 2001 Sep, 64(9), 1299 - 304
Survival of salmonellae in pasteurized, refrigerated calcium-fortified orange juice; Sharma M et al.; Studies were done to determine the survival of salmonellae in orange juice as affected by fortification with calcium . Four brands of commercially pasteurized orange juice fortified with calcium (350 mg/240-ml serving) and nonfortified juice were inoculated separately with three types of inocula: strains of Salmonella Muenchen (inoculum 1), serotypes of human and animal origin (inoculum 2), and isolates from raw produce- and juice-associated outbreaks (inoculum 3) . Juice inoculated with populations of 6.6 to 7.0 log10 CFU of Salmonella per ml was held at 4 degrees C for up to 32 days . The number of cells of inoculum 1 that survived in juice fortified with calcium lactate/tricalcium phosphate (CaL/TCP) was significantly lower (P < or = 0.05) (2.80 log10 CFU/ml) than in nonfortified juice (3.50 log10 CFU/ml) after 32 days' storage . Death of salmonellae in inocula 1 and 2 was less in juice fortified with TCP (3.21 and 3.33 log10 CFU/ml, respectively) than in the nonfortified juice (3.75 and 4.15 log10 CFU/ml, respectively) . During the 32-day storage period, populations in inocula 1 and 3 showed significantly less inactivation (2.62 and 3.12 log10 CFU/ml, respectively) in juice fortified with calcium citrate (CC) than in nonfortified juice (3.14 and 3.60 log10 CFU/ml, respectively) . There were no significant differences in the survival of Salmonella in juice fortified with calcium citrate malate (CCM) and nonfortified juice . Polymerase chain reaction (PCR) typing of randomly selected Salmonella colonies revealed that Salmonella Heidelberg in inoculum 2 and Salmonella Baildon and Salmonella Poona in inoculum 3 were the most prevalent at the end of the 32-day storage period at 4 degrees C, suggesting that serotypes selected for use in inocula differed in tolerance to acidic environments . This study reveals that the form of calcium used to fortify orange juice may affect the survival of Salmonella.

J Food Prot, 2001 Sep, 64(9), 1292 - 8
Wrinkled alfalfa seeds harbor more aerobic bacteria and are more difficult to sanitize than smooth seeds; Charkowski AO et al.; At least 14 separate outbreaks of food poisoning attributed to either Salmonella enterica or Escherichia coli O157:H7 have been traced to sprouts in the past decade . Seeds contaminated with human pathogens caused most of these outbreaks, thus many sprout growers are now treating alfalfa seeds with the sanitizing agent, calcium hypochlorite (Ca{OCl}2), prior to sprouting . The efficacy of alfalfa seed sanitation varies between seed lots and between seeds within each lot . Alfalfa seeds from different seed lots were sorted by type in an effort to determine if certain seed types carry more aerobic bacteria than other seed types . Seeds with a wrinkled type, characteristic of lygus bug damage, had significantly higher levels of culturable aerobic bacteria and were more difficult to sanitize than smooth, healthy seeds . After sanitation, wrinkled alfalfa seeds that had been inoculated with S . enterica ser . Newport carried significantly higher levels of Salmonella Newport than smooth seeds . If S . enterica is present on wrinkled seeds in naturally contaminated seed lots, it may be difficult to chemically sanitize the seed lot . Removal of the wrinkled alfalfa seeds from the seed lots, perhaps by adapting color sorting equipment similar to that used to sort rice grains and other seeds, should reduce the level of aerobic bacteria in seed lots and may result in lower levels of human pathogens on contaminated alfalfa seeds.

J Food Prot, 2001 Sep, 64(9), 1286 - 91
Effect of sanitizer treatments on Salmonella Stanley attached to the surface of cantaloupe and cell transfer to fresh-cut tissues during cutting practices; Ukuku DO et al.; The ability of Salmonella Stanley to attach and survive on cantaloupe surfaces, its in vivo response to chlorine or hydrogen peroxide treatments, and subsequent transfer to the interior tissue during cutting was investigated . Cantaloupes were immersed in an inoculum containing Salmonella Stanley (10(8) CFU/ml) for 10 min and then stored at 4 or 20 degrees C for up to 5 days . Periodically, the inoculated melons were washed with chlorine (1,000 ppm) or hydrogen peroxide (5%), and fresh-cut tissues were prepared . The incidence of Salmonella Stanley transfer from the rinds to the fresh-cut tissues during cutting practices was determined . A population of 3.8 log10 CFU/cm2 of Salmonella Stanley was recovered from the inoculated rinds . No significant (P < 0.05) reduction of the attached Salmonella population was observed on cantaloupe surfaces stored at 4 or 20 degrees C for up to 5 days, and the population was not reduced after washing with water . Salmonella Stanley was recovered in fresh-cut pieces prepared from inoculated whole cantaloupes with no sanitizer treatment . Washing with chlorine or hydrogen peroxide solutions was most effective immediately after inoculation, resulting in an approximate 3.0-log10 CFU/cm2 reduction, and the level of recovered Salmonella population transferred to fresh-cut samples was reduced to below detection . The effectiveness of both treatments diminished when inoculated cantaloupes stored at 4 or 20 degrees C for more than 3 days were analyzed, and the fresh-cut pieces prepared from such melons were Salmonella positive . Salmonella outgrowth occurred on inoculated fresh-cut cubes stored above 4 degrees C.

J Food Prot, 2001 Sep, 64(9), 1279 - 85
Optimization of iron supplementation for enhanced detection of Salmonella Enteritidis in eggs; Chen H et al.; Mixed raw egg contents were inoculated with approximately 10 CFU of Salmonella Enteritidis and supplemented with 0 to 7 mg of FeSO4 per g of egg contents . Egg contents were then incubated at 37 degrees C, and Salmonella Enteritidis colonies were enumerated for up to 106 h . Iron supplementation significantly enhanced the growth of Salmonella Enteritidis . Within the first 24 h of incubation, the optimum iron level for Salmonella Enteritidis growth in egg contents was between 0.2 and 2 mg of FeSO4 per g of egg contents . After 24 h of incubation at 37 degrees C . Salmonella Enteritidis counts in eggs supplemented with 0.5 mg of FeSO4 per g of egg contents consistently reached approximately 1 x 10(9) CFU/ml, whereas Salmonella Enteritidis counts in eggs without iron supplementation varied from less than 5 CFU/ml to 8.4 x 10(6) CFU/ml . A 3 by 3 factorial design was used to study the effect of type of preenrichment and level of iron supplementation on the growth of Salmonella Enteritidis in egg contents . No significant differences in Salmonella Enteritidis counts between preenrichment and nonpreenrichment treatments were observed when egg contents were supplemented with 0.5 mg of FeSO4 per g of egg contents . It was concluded that preenrichment was not necessary for isolation of Salmonella Enteritidis from eggs . The effect of iron supplementation on the sensitivity of detection by the direct plating method was investigated . The direct plating method detected a significantly higher percentage of Salmonella Enteritidis in raw egg contents supplemented with 0.5 mg of FeSO4 per g of egg contents (90%) than in raw egg contents without iron supplementation (63.3%).

Int J Toxicol, 2001 Jul-Aug, 20(4), 207 - 17
Evaluation of the acute and subchronic toxic effects in mice, rats, and monkeys of the genetically engineered and Escherichia coli cytosine deaminase gene-incorporated Salmonella strain, TAPET-CD, being developed as an antitumor agent; Lee KC et al.; TAPET-CD, a genetically engineered Salmonella strain with chromosomal-incorporated cytosine deaminase (CD) gene, has been shown to selectively accumulate tumors, suppress tumor growth, and convert 5-fluorocytosine (5-FC, an antifungal agent) to the antitumor agent 5-fluorouracil (5-FU) in animals . The current studies investigated the safety of TAPET-CD, and TAPET-CD/5-FC combination, in animals . In C57BL/6 mice (n = 10 females/dose), the maximum nonlethal dose of TAPET-CD (intravenous {IV} bolus) was 1 x 10(6) colony-forming units (cfu)/mouse, or > 10,000 x that of wild-type Salmonella . In Sprague-Dawley rats (n = 4/sex/group), after treatment with 4 weekly cycles of TAPET-CD (an IV injection/cycle at 1 x 10(5), 3 x 10(5), 1 x 10(6), 3 x 10(6), or 1 x 10(7) cfu/rat on day 1) and 5-FC (per os twice daily {PO b.i.d.}, 250 mg/kg on days 2-7/cycle), clinical signs and mortality were evaluated daily, body weight and clinical pathology weekly, and gross necropsy on day 29 . No treatment-related toxicity, although occasional and mild clinical signs (e.g., dehydration), increased hepatic enzyme/function values and white blood cells, splenic enlargement, and bilateral red discoloration of the kidneys, were observed . In cynolmogus monkeys, Experiment 1 involved treatment with TAPET-CD (IV injection at 1 x 10(9) cfu/monkey) . Clinical signs and mortality were evaluated daily, body weight weekly, and gross necropsy on days 2, 7, and 31 (1/sex/time point) . Experiment 2 involved treatment with TAPET-CD (IV injection at 1 x 10(9) and 1 x 10(10) cfu/monkey in Groups 1 to 3 and Groups 4 to 6, respectively) on day 1 and 5-FC (PO b.i.d . at 250, 500, and 1000 mg/kg in Groups 1 to 3, and 500, 1500, and 0 mg/kg in Groups 4 to 6, respectively) on days 4 to 17 (n = 1/sex/group) . Clinical signs and mortality were evaluated daily; body weight and clinical pathology on days 1, 2, 4, 14, and 18; body temperature on days 1, 4, and 18; ophthalmic examinations on days 3 and 17; and gross necropsy and histopathology on day 18 . Experiment 1 indicated that TAPET-CD at 1 x 10(9) or 1 x 10(10) cfu/monkey was well tolerated, with only occasional mild clinical signs (i.e., emesis, vomiting, inappetance, loose/infrequent/absence of stool), increases in hepatic enzyme/function values, and splenic enlargement . Experiment 2 indicated that TAPET-CD/5-FC combination had a maximum tolerated dose (MTD) of 1 x 10(10) cfu/monkey for TAPET-CD and 500 mg/kg for 5-FC in monkeys . Supra-MTDs induced renal toxicity . In conclusion, TAPET-CD had a good safety profile (reflected by the extremely large amount of TAPET-CD needed to induce mortality or toxicity) in mice, rats, and monkeys . More adverse events were observed with TAPET-CD/5-FC combination when compared to TAPET-CD and these events were similar to the reported effects of 5-FU, suggesting the involvement of 5-FU.

Proc Natl Acad Sci U S A, 2001 Sep 25, 98(20), 11638 - 43 Epub 2001 Sep 18.
Supermolecular structure of the enteropathogenic Escherichia coli type III secretion system and its direct interaction with the EspA-sheath-like structure; Sekiya K et al.; Enteropathogenic Escherichia coli (EPEC) secretes several Esp proteins via the type III secretion system (secreton) . EspA, EspB, and EspD are required for translocation of the effector proteins into host cells, in which EspB and EspD are thought to form a pore in the host membrane . Recent study has shown that EspA forms a filamentous structure that assembles as a physical bridge between bacteria and host cell surfaces, which then functions as a conduit for the translocation of bacterial effectors into host cells . To investigate the supermolecular structure of the type III secreton in EPEC, we partially purified it from the bacteria membrane and observed it via transmission electron microscopy . The EPEC type III secreton was composed of a basal body and a needle part and was similar to those of Salmonella and Shigella, except for a sheath-like structure at the tip of the needle . The length of sheath-like structures varied; it extended more than 600 nm and was 10 times longer than the Shigella needle part . The putative major needle component, EscF, was required for both secretion of Esp proteins and needle complex formation . Interestingly, elongation of the sheath-like structure was observed under constitutive expression of EspA but not of EscF . Furthermore, the transmission electron microscopy view with immunogold labeled anti-EspA antibodies clearly showed that EspA is a component of the sheath-like structure . This study revealed, to our knowledge for the first time, the supermolecular structure of the EPEC type III secreton and its direct association with the EspA-sheath-like structure.

Microb Pathog, 2001 Oct, 31(4), 201 - 4
Secretion of a putative cytotoxin in multiple antibiotic resistant Salmonella enterica serotype Typhimurium phagetype DT104; Carlson SA et al.; Salmonella enterica serotype Typhimurium phagetype DT104 (DT104) is a multiple antibiotic-resistant pathogen . DT104 infections have been reported in a multitude of hosts including humans, companion animals, livestock and wildlife . Recently, several isolates of DT104 were recovered from veal calves exhibiting abomasitis, a finding that is inconsistent with classic salmonellosis . One of these isolates was used in murine ligated loop experiments where it was observed that multiresistant DT104 can elaborate a putative cytotoxin . Thus it appears that DT104 has the ability to evade pharmacologic interventions, via antibiotic resistance, and elaborate a toxin that can damage cells .

Comp Immunol Microbiol Infect Dis, 2001 Oct, 24(4), 207 - 16
Control of Salmonella enteritidis phage type 4 experimental infection by fosfomycin in newly hatched chicks; Fernandez A et al.; One hundred and twenty 1-day-old broiler chickens were divided into four groups: group I unmedicated and orally challenged with 1.5 x 10(8) cfu of Salmonella enteritidis phage type 4; group F infected and treated with 300 ppm of fosfomycin in their drinking water; group CF uninfected and treated, and group C maintained as a control group . Their performance, clinical signs, S . enteritidis PT4 reisolation and biochemistry variables were compared . Group F showed fewer symptoms and gross lesions than those from group 1 . Fosfomycin treatment at 300 ppm improved body weight at 7 days of age by 42.3% . S . enteritidis PT4 reisolation in group I was higher than in the treated group, but total decontamination of challenged birds was not achieved . There was an increase in the levels of total protein and globulins in group I but not in the treated group . Fosfomycin caused no adverse effects on chickens from group CF, assessed by performance and biochemical variables . The results indicate that fosfomycin could be used in the treatment of S . enteritidis PT4 experimental infection.

Am J Vet Res, 2001 Sep, 62(9), 1399 - 401
In vitro inhibition of Salmonella organisms isolated from reptiles by an inactivated culture of microcin-producing Escherichia coli; Wooley RE et al.; OBJECTIVE: To determine whether an inactivated culture of a microcin-producing avian Escherichia coli was capable of killing Salmonella isolates from reptiles in an in vitro test system . SAMPLE POPULATION: 57 Salmonella isolate from reptiles . PROCEDURE: A wild-type avian E . coli electrotransformed with a plasmid coding for the production of microcin 24 was tested in an in vitro microassay system for its ability to kill 57 Salmonella spp isolated from reptiles . The reptile population included snakes, iguana, frilled lizards, turtles, other lizards, and unspecified reptiles . RESULTS: 44 of the Salmonella isolates were inhibited strongly, compared with the in vitro assay controls; 12 had weak inhibition, and 1 was not inhibited by the microcin-producing E . coli . Thirteen of the 57 isolates had resistance to at least 1 antibiotic, primarily streptomycin . There were 9 O serogroups identified in the 57 isolates, with serogroup H being the most prevalent (18 to 57) . CONCLUSION AND CLINICAL RELEVANCE: Antibiotics are not recommended to eliminate Salmonella organisms from reptiles because of the development of antibiotic resistance . Further studies are necessary to determine whether the use of microcin-producing bacteria will be effective in controlling Salmonella infections in companion reptiles.

Lett Appl Microbiol, 2001 Oct, 33(4), 311 - 5
Influence of phage population on the phage-mediated bioluminescent adenylate kinase (AK) assay for detection of bacteria; Wu Y et al.; AIMS: The effect of phage concentration on the activity of adenylate kinase (AK) released from the cells lysed during infection was investigated in order to optimize a bioluminescent phage-mediated method for bacterial enumeration . METHODS AND RESULTS: The number of bacteria lysed by phages specific to Salmonella enteritidis and E . coli was determined using a bioluminescent method for the detection of AK released . In order to optimize the assay, the effect of phage concentration and time of infection on the amount of AK released was investigated . The release of AK was greatest at a multiplicity of infection (moi) of 10-100 . CONCLUSION: The amount of AK released from Salmonella enteritidis and E . coli G2-2 cells by specific phages, SJ2 and AT20, respectively, depended on the type of bacteria, the stage of growth, the nature of phage, moi and time . SIGNIFICANCE AND IMPACT OF THE STUDY: An assay is described which allows detection of E . coli and Salmonella Enteritidis within 2 h at levels of 103 cfu ml-1.

Poult Sci, 2001 Sep, 80(9), 1323 - 8
Pathogenicity of environmental origin Salmonellas in specific pathogen-free chicks; Dhillon AS et al.; Two hundred sixty 1-d-old specific pathogen-free (SPF), Single Comb White Leghorn chicks were used in this study to determine pathology caused by Salmonella enteritidis (SE) isolated from a poultry environment . The chicks were subdivided into 10 equal groups of 26 chicks each . Eight groups of chicks were inoculated individually with 0.5 mL of brain heart infusion broth culture containing 1 x 10(6) cfu of SE phage type (PT) -8 (1, 2, 3), SE PT5 A (1, 2), or SE PT4 (Ch-env-CA, chicken-CA, and human) by crop gavage . One group of 26 chicks were inoculated with 1 x 10(6) cfu of Salmonella pullorum per bird by crop gavage . Another group of 26 chicks were kept as an uninoculated control group . All the chicks were observed daily for clinical signs and mortality . Salmonella was reisolated from different organs at 7, 14, 21, and 28 postinoculation (DPI) . All of the chicks were weighed individually at each interval . Two chicks at random from each group were euthanised and necropsied at each DPI for gross pathology . Selected tissues were examined for histopathological changes at 7 and 14 DPI . Dead chicks were examined for gross and histopathological lesions . Mortality rates were 30.7, 15.3, and 7.6% in the groups inoculated with S . pullorum, SE PT5A, and SE PT4 (chicken-CA), respectively . No mortality or clinical sign were observed in other treatment groups or in uninoculated control groups . Cecal pouches were found to be the ideal organ for reisolation of Salmlonella at acute or chronic infection compared with other organs . Mean body weights were reduced to 1.8 to 12.6% in inoculated groups compared with the uninoculated control group . The consistent gross and hispathological lesions were of peritonitis, perihepatitis, yolk sac infection, and enteritis . Subclinical Salmlonella infection identified in this study resulted in reduced body weights of inoculated birds compared with uninoculated controls.

J Vet Med Sci, 2001 Aug, 63(8), 860 - 5
Inflammatory cytokines and antigen-responsive mononuclear cells in peripheral blood of cattle infected with Salmonella takoradi; Konna S et al.; To determine the immunological response in lactating dairy cows infected with Salmonella (S.) Takoradi, the relationships among distributions of peripheral blood mononuclear cell (PBMC) subpopulations, endotoxin concentrations and dynamics of inflammatory cytokines in blood were investigated . The ratio of CD4+ T cells to CD8+ T cells was significantly lower in the affected cattle than in the control cattle (p<0.05) to decrease in the number of CD4+ T cells in the infected cattle . In contrast, the numbers of gammadeltaT cells, MHC class II-positive cells were significantly higher in the affected cattle than in the control cattle (p<0.01 respectively) . Endotoxemia was found in all but one of the affected cattle . Serum IL-1 and IL-6 bioactivities were significantly higher in the affected cattle than in the control cattle (IL-1, p<0.05; IL-6 . p<0.01) . Serum TNF-alpha activities and levels were not detected in the control and affected cattle . The activities of proinflammatory cytokines determined by the bioassay are important to the relationships between concentration of endotoxin, cytokines and clinical signs . such as leukocytosis, leukopenia, fever or bacterial shedding . Serum IL-2 levels were lower in the affected cattle than in the control cattle . Serum IFN-y was not detected in the affected cattle except one . These results by the ELISA seemed to reflect the condition of subpopulation in the PBMCs from the shedding cattle . The present results suggest that cellular immunity is suppressed while the humoral immunity is activated in acute bovine salmonellosis.

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