Salmonella

Int J Food Microbiol, 1998 Mar 3, 40(1-2), 27 - 34
Phage typing combined with pulsed-field gel electrophoresis and random amplified polymorphic DNA increases discrimination in the epidemiological analysis of Salmonella enteritidis strains; Laconcha I et al.; Phage typing (PT) combined with pulsed-field gel electrophoresis (PFGE) and a random amplified polymorphic DNA (RAPD) fingerprinting method was used to characterize Salmonella enteritidis strains . Twenty-four epidemiologically unrelated isolates, sampled from diverse ecological niches and fifteen isolates from four well-defined outbreaks of foodborne gastroenteritis, were studied . Seven phage types, with a predominance of PT 4 (63% of isolates), were observed when analysing the epidemiologically unrelated group . PT 4 was detected in all of the ecological niches studied, including food and fecally polluted river and beach water . The discriminatory power for phage typing, the average probability that the typing system will assign a different type to two unrelated strains randomly sampled in the microbial population, was 0.62 . Ten PFGE pattern types were obtained with Xba I restriction endonuclease enzyme among the unrelated isolates; thirteen isolates belonged to PFGE pattern type 1 and the rest of the PFGE types were assigned to one or two isolates . The Dice coefficient clustered the similarities of the PFGE patterns between 80-100% . PFGE showed a discriminatory power of 0.72 . Five clearly distinct RAPD patterns were observed with the OPS-19 oligonucleotide, but the discrimination obtained was low (0.46) . The combination of the three typing methods increased the number of types to seventeen, giving high discrimination (0.92) . Seven of the isolates recovered from various ecological niches belonged to the combination PT 4/PFGE 1/RAPD A and other combinations were unique or included only two strains . The four epidemiologically well-defined foodborne outbreaks were associated with the PT 4 phage type . In two of the outbreaks, other phage types (PT 7a and RDNC) were also observed in two isolates . Most of the isolates belonging to the foodborne outbreaks had an identical PFGE pattern (PFGE pattern type 1), but a difference in a restriction band was observed in an isolate belonging to an outbreak . Two RAPD patterns were observed in the outbreaks; RAPD pattern type A was detected in three of the four outbreaks . When the combined typing method was applied to the study, high concordance was observed and most of the outbreak strains belonged to the combination PT 4/PFGE 1/RAPD A . It is concluded that the combination of phage type with PFGE and RAPD provides a powerful discriminatory tool for the epidemiological analysis of unrelated and related strains of S . enteritidis.

Int J Food Microbiol, 1998 Mar 3, 40(1-2), 1 - 8
Prevalence of Salmonella in poultry carcasses and their products in Belgium; Uyttendaele MR et al.; During four subsequent years (1993 until 1996), a study was conducted to isolate and characterize Salmonella in poultry carcasses and their products sold in Belgium . This was a semiquantitative approach (absence per 100 cm2 or 25 cm2 or 25 g and absence per cm2 or g) to elucidate the degree of Salmonella contamination of the poultry . Serotyping was performed during the last two and a half years . Samples were frozen and kept at -20 degrees C before analysis . This may have influenced the number of Salmonella recovered . No improvement in the rate of contamination was noted during these four years, with rates being 19.4% for 1993, 24.1% for 1994, 21.9% for 1995 and 36.7% for 1996 . A 100% increase of Salmonella-positive samples resulted from cutting up the carcasses into individual parts . Chicken parts were more often contaminated with Salmonella than turkey parts . Boiling hen carcasses showed the highest Salmonella contamination . Prepared poultry, chicken parts and boiling hen carcasses are sometimes associated with Salmonella contamination levels of > 1 cfu/cm2 or g . In 1996, respectively 15.1%, 4.2% and 4.2% of highly contaminated samples (> 1 cfu/cm2 or g) were found for these product groups . The predominant three serotypes were S . enteritidis (16.3%), S . hadar (15.5%) and S . virchow (14.1%) . S . newport was frequently isolated from turkey products.

J Clin Microbiol, 1998 Apr, 36(4), 971 - 4
Epidemiological analysis of Salmonella enteritidis isolates from humans and broiler chickens in Thailand by phage typing and pulsed-field gel electrophoresis; Boonmar S et al.; To determine the phage types (PT) of Salmonella enteritidis found in Thailand and to clarify the potential for human infection by S . enteritidis in broiler chicken meat, human and poultry isolates taken from Thailand between 1990 and 1997 were phage typed and analyzed by pulsed-field gel electrophoresis (PFGE) . Ten different PT were found among the 302 isolates phage typed, with PT 4 being the most frequent in human (73.9%) and poultry (76.2%) isolates, followed by PT 1 (8.0%), 8 (3.6%), and 7a (2.2%) in human isolates and by PT 7a (4.9%), 1 (3.7%), and 12 (2.4%) in poultry isolates . Of the 53 isolates analyzed by PFGE, 45 showed an indistinguishable pattern (pattern A) by BlnI-digested PFGE and the other 8 isolates showed a very similar pattern that differed by only a few bands . These results indicate the spread of a genetically identical clone of S . enteritidis in humans and poultry in Thailand.

Clin Cardiol, 1998 May, 21(5), 368 - 70
Successful conservative treatment of nontyphoid salmonella endocarditis involving a bioprosthetic valve; Goerre S et al.; We report a first case of Salmonella enteritidis endocarditis involving a bioprosthetic aortic valve . Despite additional native tricuspid valve involvement, the clinical course was favorable using an antibiotic regimen of ciprofloxacin and netilmicin . Although Salmonella prosthetic valve endocarditis is considered an indication for surgical replacement of the prosthesis, this case indicates that prolonged treatment with fluoroquinolones may be an alternative provided that the hemodynamic situation is stable.

Epidemiol Infect, 1998 Mar, 120(2), 129 - 38
Risk factors for typhoid fever in an endemic setting, Karachi, Pakistan; Luby SP et al.; We conducted a study to evaluate risk factors for developing typhoid fever in a setting where the disease is endemic in Karachi, Pakistan . We enrolled 100 cases with blood culture-confirmed Salmonella typhi between July and October 1994 and 200 age-matched neighbourhood controls . Cases had a median age of 5.8 years . In a conditional logistic regression model, eating ice cream (Odds ratio {OR} = 2.3; 95% confidence interval {CI} 1.2-4.2, attributable risk {AR} = 36%), eating food from a roadside cabin during the summer months (OR = 4.6, 95% CI 1.6-13.0; AR = 18%), taking antimicrobials in the 2 weeks preceding the onset of symptoms (OR = 5.7, 95% CI 2.3-13.9, AR = 21%), and drinking water at the work-site (OR = 44.0, 95% CI 2.8-680, AR = 8%) were all independently associated with typhoid fever . There was no difference in the microbiological water quality of home drinking water between cases and controls . Typhoid fever in Karachi resulted from high-dose exposures from multiple sources with individual susceptibility increased by young age and prior antimicrobial use . Improving commercial food hygiene and decreasing unnecessary antimicrobial use would be expected to decrease the burden of typhoid fever.

Epidemiol Infect, 1998 Mar, 120(2), 125 - 8
National outbreak of Salmonella senftenberg associated with infant food; Rushdy AA et al.; Eight cases of Salmonella senftenberg infection in infants were identified in the first half of 1995 in England, five were indistinguishable S . senftenberg strains . A case-control study showed an association between illness and consumption of one brand of baby cereal (P = 0.03) . The cereal manufacturer reported isolating S . senftenberg in June 1994 from an undistributed cereal batch . Outbreak strains and the cereal strain were all plasmid-free in contrast to other human isolates of S . senftenberg in the same period . Changes in the production process were implemented to prevent further contamination . Surveillance centres should strengthen the detection and investigation of outbreaks of gastrointestinal infection in susceptible groups, especially young children . In this outbreak, the study of only five cases led to identification of the vehicle of infection . Even when few cases are reported, epidemiological investigation in conjunction with molecular typing may lead to public health action which prevents continuing or future outbreaks.

Antimicrob Agents Chemother, 1998 May, 42(5), 1288 - 9
Tetracycline resistance in Salmonella enterica subsp . enterica serovar Dublin; Frech G et al.; The 47-kbp plasmid pGFT1 from Salmonella enterica subsp . enterica serovar Dublin mediated tetracycline resistance via a tet(A) gene located on an integrated copy of a Tn1721-analogous transposon . The integration site of the transposon was located within the reading frame of a fip gene . Plasmid pGFT1 was shown to be conjugative and to be able to replicate and express tetracycline resistance in Escherichia coli.

Nature, 1998 May 7, 393(6680), 79 - 82
Salmonella typhi uses CFTR to enter intestinal epithelial cells; Pier GB et al.; Homozygous mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) cause cystic fibrosis (CF) . In the heterozygous state, increased resistance to infectious diseases may maintain mutant CFTR alleles at high levels in selected populations . Here we investigate whether typhoid fever could be one such disease . The disease is initiated when Salmonella typhi enters gastrointestinal epithelial cells for submucosal translocation . We found that S . typhi, but not the related murine pathogen S . typhimurium, uses CFTR for entry into epithelial cells . Cells expressing wild-type CFTR internalized more S . typhi than isogenic cells expressing the most common CFTR mutation, a phenylalanine deleted at residue 508 (delta508) . Monoclonal antibodies and synthetic peptides containing a sequence corresponding to the first predicted extracellular domain of CFTR inhibited uptake of S . typhi . Heterozygous deltaF508 Cftr mice translocated 86% fewer S . typhi into the gastrointestinal submucosa than wild-type Cftr mice; no translocation occurred in deltaF508 Cftr homozygous mice . The Cftr genotype had no effect on the translocation of S . typhimurium . Immunoelectron microscopy revealed that more CFTR bound to S . typhi in the submucosa of Cftr wild-type mice than in deltaF508 heterozygous mice . We conclude that diminished levels of CFTR in heterozygotes may decrease susceptibility to typhoid fever.

Genetika, 1998 Feb, 34(2), 308 - 12
{Genotoxic effects of metabolic derivatives of the new drug phosphabenzide}; Il'inskaia ON et al.; Genotoxic action of four possible metabolites of the new tranquilizer phosphabenzide (acetylphosphabenzide, diphenylphosphinylacetic acid, phosphabenzide hydrazone with pyruvic acid, bis-1,2-(diphenylphosphinylacetyl)hydrazine) has been studied . These metabolites belong to slightly toxic phosphororganic compounds . The Ames Salmonella/microsomes tests performed on strains TA100 and TA98 showed that of these compounds only acetylphosphabenzide possessed mutagenic action . Metabolic activation of liver microsomes decreased the mutagenic effect . The mechanism of action of acetylphosphabenzide is likely to involve the formation of acetylhydrazine, capable of producing active electrophiles attacking DNA.

Electrophoresis, 1998 Apr, 19(4), 569 - 72
Chromosomal rearrangements in enteric bacteria; Sanderson KE et al.; Early genetic studies showed conservation of gene order in the enteric bacteria . Two recent methods using pulsed field gel electrophoresis (PFGE) to determine the physical map of the genome are: (i) partial digestion with the endonuclease I-CeuI, which digests the DNA of bacteria in the rrn operon for rRNA (ribosomal RNA), thus establishing the "rrn genomic skeleton" (the size in kbp of the intervals between rRNA operons); (ii) analysis of XbaI and B1nI sites within Tn10 insertions in the chromosome . The order of I-CeuI fragments, which is ABCDEFG in S . typhimurium LT2 and E . coli K-12, was found to be conserved in most Salmonella species, most of which grow in many hosts (host-generalists) . However, in S . typhi, S . paratyphi C, S . gallinarum, and S . pullorum, species which are host-specialized, these fragments are rearranged, due to homologous recombination between the rrn operons, resulting in translocations and inversions . Inversions and translocations not involving the rrn operons are seldom detected except for inversions over the TER (termination of replication) region . Additive genetic changes (due to lateral transfer resulting in insertion of nonhomologous DNA) have resulted in "loops" containing blocks of DNA which provide new genes to specific strains, thus driving rapid evolution of new traits.

Pharm Res, 1998 Apr, 15(4), 544 - 9
Drug targeting by polyalkylcyanoacrylate nanoparticles is not efficient against persistent Salmonella; Page-Clisson ME et al.; PURPOSE: We have investigated the efficacy of colistin and ciprofloxacin, free or bound to polyalkylcyanoacrylate nanoparticles, for the targeting and eradication of Salmonella persisting in the organs of the mononuclear phagocyte system . METHODS: A model of persistent S . typhimurium infection was developed in C57BL/6 mice using i.v . inoculation of the plasmid-cured strain C53 . RESULTS: In vivo and ex vivo experiments showed that the persisting bacteria seem to evolve to a nongrowing state during experimental salmonellosis . In vivo treatment with free or nanoparticle-bound colistin did not significantly reduce the number of viable Salmonella C53, either in the liver or the spleen of infected mice . In contrast, in vivo treatment with ciprofloxacin led to a significant decrease of bacterial counts in the liver whatever the stage of infection and the form used . However, none of the treatments were able to sterilize the spleen or the liver . In ex vivo experiments, colistin was only active against bacteria recovered during the early phase of infection, whereas ciprofloxacin exerted its activity at all times postinfection . CONCLUSIONS: We suggest that the micro-environment in which the bacterial cells persist in vivo probably causes dramatic changes in their susceptibility to antimicrobial agents.

Res Commun Mol Pathol Pharmacol, 1998 Feb, 99(2), 233 - 9
Effects of hydrazine sulfate on galactosamine-sensitized endotoxic shock in ten-day-old rats; Ravindranath T et al.; Patients who have liver diseases are susceptible to septic shock . Galactosamine induces liver damage and increases endotoxin-sensitivity . Hydrazine stimulates pituitary-adrenal axis and decreases mortality in galactosamine-sensitized endotoxic shock in the adult . However, as pituitary-adrenal function in the newborn is immature, the effects of hydrazine on galactosamine-sensitized endotoxic shock in the newborn remained unclear . In the present study, galactosamine-sensitized endotoxic shock was induced and treated with hydrazine in ten-day-old rats . Galactosamine (600 mg/kg) plus Salmonella enteritidis lipopolysaccharide (LPS; 0.01 mg/kg) induced hypoglycemia, lactacidemia and resulted in high mortality . Hydrazine at the dose of 20, 50 or 80 mg/kg did not alter the hypoglycemia, lactacidemia or morality . Dexamethasone ameliorated the hypoglycemia and lactacidemia (p < 0.05) and decreased the morality (p < 0.05) . The lack of beneficial effects of hydrazine in galactosamine-sensitized endotoxic shock in ten-day-old rats may be related to immature pituitary-adrenal function and suppression of gluconeogenesis by hydrazine.

Enferm Infecc Microbiol Clin, 1998 Jan, 16(1), 19 - 24
{Abscess of the psoas muscle: analysis of 11 cases and review of the literature}; Laguna P et al.; BACKGROUND: Abscess of the psoas muscle (AP) is an infrequent disease of difficult diagnosis, developing spontaneously (primary AP) or by extension of a subjacent infection (secondary AP) . In recent years changes have been observed in its etiology, advances in its diagnosis and modifications in the treatment schedules . METHODS: The cases of AP diagnosed from 1983-1996 were retrospectively studied . RESULTS: The cases included 11 AP, 5 (45%) primary and 6 (55%) secondary, of which the source of origin were: spondylitis in four, sacroiliac arthritis in one and intestinal in another . The clinical presentation was characterized by its prolonged course (evolution of symptoms greater than 30 days in 64% of the cases), with the most frequent symptoms being flank/abdominal pain (82%) and hip/inguinal pain (45%), with fever being presented in only 36% . The diagnostic profitability of echography and computerized tomography (CT) were 57% (4/7) and 91% (10/11), respectively . One case was diagnosed with magnetic resonance . The causal microorganisms were: Mycobacterium tuberculosis (36% of the cases), Staphylococcus aureus (18%), polymicrobian flora (18%) and Salmonella enteritidis, Streptococcus intermedius and Escherichia coli in 9% each . Eight cases (73%) underwent percutaneous (5 cases) and surgical (3 cases) drainage, with the evolution being favorable in 10 (91%) and death in one despite adequate medicosurgical treatment . CONCLUSIONS: The clinical presentation of AP is often unspecific, thereby delaying its diagnosis, and thus, CT is the procedure of choice . The tuberculous etiology continues to be frequent in our environment . Ultrasonographic or CT guided percutaneous drainage is a valid therapeutic alternative versus surgery.

Biochemistry, 1998 Apr 7, 37(14), 4935 - 45
Mechanistic studies of the biosynthesis of paratose: purification and characterization of CDP-paratose synthase; Hallis TM et al.; The 3,6-dideoxyhexoses can be found in the cell wall lipopolysaccharide of Gram-negative bacteria, where they have been shown to be the dominant antigenic determinants . All naturally occurring 3,6-dideoxyhexoses, with colitose as the only exception, are biosynthesized via a complex pathway that begins with CDP-d-glucose . Included in this pathway is CDP-paratose synthase, an essential enzyme in the formation of the 3,6-dideoxy sugars, CDP-paratose and CDP-tyvelose . Recently, the gene encoding CDP-paratose synthase in Salmonella typhi, rfbS, has been identified and sequenced {Verma, N., and Reeves, P . (1989) J . Bacteriol . 171, 5694-5701} . On the basis of this information, we have amplified the rfbS gene by polymerase chain reaction (PCR) from S . typhi and cloned this gene into a pET-24(+) vector . Expression and purification of CDP-paratose synthase have allowed us to fully characterize the catalytic properties of this enzyme, which is a homodimeric protein with a preference for NADPH over NADH . It catalyzes the stereospecific hydride transfer of the pro-S hydrogen from the C-4' position of the reduced coenzyme to C-4 of the substrate, CDP-3,6-dideoxy-D-glycero-D-glycero-4-hexulose . The overall equilibrium of this catalysis greatly favors the formation of the reduced sugar product and the oxidized coenzyme . Interestingly, this enzyme also exhibits a high affinity for NADPH with a much smaller dissociation constant (Kia) of 0.005 +/- 0.002 microM compared to the Km of 26 +/- 8 microM for NADPH . While this unusual property complicated the interpretation of the kinetic data, the kinetic mechanism of CDP-paratose synthase as explored by the combination of bisubstrate kinetic analysis, product inhibition studies, and dead-end competitive inhibition studies is most consistent with a Theorell-Chance mechanism . The present study on CDP-paratose synthase, a likely new member of the short-chain dehydrogenase family, represents the first detailed characterization of this type of ketohexose reductase, many of which may share similar properties with CDP-paratose synthase.

J Biol Chem, 1998 Apr 10, 273(15), 8849 - 59
The assembly system for the lipopolysaccharide R2 core-type of Escherichia coli is a hybrid of those found in Escherichia coli K-12 and Salmonella enterica . Structure and function of the R2 WaaK and WaaL homologs; Heinrichs DE et al.; In Escherichia coli F632, the 14-kilobase pair chromosomal region located between waaC (formerly rfaC) and waaA (kdtA) contains genes encoding enzymes required for the synthesis of the type R2 core oligosaccharide portion of lipopolysaccharide . Ten of the 13 open reading frames encode predicted products sharing greater than 90% total similarity with homologs in E . coli K-12 . However, the products of waaK (rfaK) and waaL (rfaL) each resemble homologs in Salmonella enterica serovar Typhimurium but share little similarity with E . coli K-12 . The F632 WaaK and WaaL proteins therefore define differences between the type R2 and K-12 outer core oligosaccharides of E . coli lipopolysaccharides . Based on the chemical structure of the core oligosaccharide of an E . coli F632 waaK::aacC1 mutant and in vitro glycosyltransferase analyses, waaK encodes UDP-N-acetylglucosamine:(glucose) lipopolysaccharide alpha1, 2-N-acetylglucosaminyltransferase . The WaaK enzyme adds a terminal GlcNAc side branch substituent that is crucial for the recognition of core oligosaccharide acceptor by the O-polysaccharide ligase, WaaL . Results of complementation analyses of E . coli K-12 and F632 waaL mutants suggest that structural differences between the WaaL proteins play a role in recognition of, and interaction with, terminal lipopolysaccharide core moieties.

J Biol Chem, 1998 Apr 10, 273(15), 8680 - 90
Binding of bacterial peptidoglycan to CD14; Dziarski R et al.; The hypothesis that soluble peptidoglycan (sPGN, a macrophage-activator from Gram-positive bacteria) binds to CD14 (a lipopolysaccharide (LPS) receptor) was tested . sPGN specifically bound to CD14 in the following three assays: binding of soluble 32P-CD14 (sCD14) to agarose-immobilized sPGN, enzyme-linked immunosorbent assay, and photoaffinity cross-linking . sCD14 also specifically bound to agarose-immobilized muramyl dipeptide or GlcNAc-muramyl dipeptide but not to PGN pentapeptide . Binding of sCD14 to both sPGN and ReLPS (where ReLPS is LPS from Salmonella minnesota Re 595) was competitively inhibited by unlabeled sCD14, 1-152 N-terminal fragment of sCD14, sPGN, smooth LPS, ReLPS, lipid A, and lipoteichoic acid but not by dextran, dextran sulfate, heparin, ribitol teichoic acid, or soluble low molecular weight PGN fragments . Binding of sCD14 to sPGN was slower than to ReLPS but of higher affinity (KD = 25 nM versus 41 nM) . LPS-binding protein (LBP) increased the binding of sCD14 to sPGN by adding another lower affinity KD and another higher Bmax, but for ReLPS, LBP increased the affinity of binding by yielding two KD with significantly higher affinity (7.1 and 27 nM) . LBP also enhanced inhibition of sCD14 binding by LPS, ReLPS, and lipid A . Binding of sCD14 to both sPGN and ReLPS was inhibited by anti-CD14 MEM-18 mAb, but other anti-CD14 mAbs showed differential inhibition, suggesting conformational binding sites on CD14 for sPGN and LPS, that are partially identical and partially different.

Mutat Res, 1998 Jan 30, 412(2), 131 - 8
Genotoxicity testing of methyl tertiary-butyl ether (MTBE) in the Salmonella microsuspension assay and mouse bone marrow micronucleus test; Kado NY et al.; Methyl tertiary-butyl ether (MTBE) is an oxygenated fuel additive that is present in gasoline at levels up to 15% by volume . Since the 1990 Clean Air Act amendments require the use of oxygenated gasoline in 39 areas of the USA, the use of MTBE is projected to continue to dramatically increase . As the use of MTBE increase, the potential for environmental release of MTBE from gasoline stations and automobiles will also increase . Despite its growing use as a fuel additive and its potential for increased exposure to the public, few genotoxicity data on MTBE have been published in the peer-review literature . In the present study, we tested the potential genotoxicity of MTBE in two short-term test systems, an in vitro Salmonella microsuspension assay and an in vivo mouse bone marrow micronucleus test . For the microsuspension assay, MTBE was tested at 7 dose levels of 30 to 7400 micrograms/tube in tester strain TA98, TA100, TA104, and TA1535, with and without the addition of metabolic enzymes (S9) at 4 concentration (0, 300, 600, and 1200 micrograms S9/ml final concentration) . A closed system was used to minimize loss of MTBE . The response was not significant . However, a high degree of toxicity was observed at the highest doses in all tester strains . MTBE was also tested for clastogenicity i the mouse bone marrow micronucleus test using both male and female Swiss-Webster mice . Mice were administered single intraperitoneal injections of MTBE in olive oil at 5 doses ranging from 0.25 to 1.75 g/kg . There were no significant increases in micronucleus formation at any dose of MTBE when compared with the negative control animals receiving only olive oil . MTBE was not positive when tested for point mutations and clastogenicity, using respectively, a Salmonella microsuspension assay and the mouse bone marrow micronucleus test.

Folia Med (Plovdiv), 1997, 39(4), 17 - 23
A study on some immunological parameters in infants with salmonellosis; Stoicheva M et al.; The phagocytic activity of polymorphonuclears from peripheral blood (PMN) and the qualitative characteristic of lymphocyte populations and circulating immune complexes (CIC) were studied dynamically in 35 infants with salmonellosis . The phagocytic activity of PMNs was evaluated by phagocytic index, phagocytic number, the absolute phagocytic index and the nitroblue tetrazolium test . Lymphocyte populations were determined by immunofluoroscent assay with monoclonal antibodies, and CIC by precipitation with polyethylene glycol . Decreased level of the PMNs phagocytic activity was found in the acute phase of salmonellosis . Both B- and T-lymphopenia with subset dysbalance associated with greater decrease of T4 lymphocytes were identified . During the convalescent period the immunological parameters of the bacteriologically healthy infants were close to normal whereas the Salmonella bacteria carriers demonstrated deviations which persisted in the acute phase of the disease . The immunological parameters studied can be used as additional diagnostic and prognostic criteria in infants with salmonellosis.

Prog Clin Biol Res, 1998, 397, 217 - 26
Endotoxin tolerance alters macrophage membrane regulatory G proteins; Makhlouf M et al.; Administration of sublethal doses of endotoxin (LPS) or tumor necrosis factor-alpha (TNF alpha) renders rats tolerant to supralethal doses of LPS . Peritoneal macrophages from tolerant rats are refractory to LPS induced arachidonic acid (AA) metabolism and cytokine production in vivo, and exhibit reduced membrane GTPase activity and GTP gamma S binding . Since LPS stimulated AA metabolism is mediated by Gi alpha proteins, we sought to determine whether Gi alpha and/or other G proteins are reduced in LPS tolerance . Rats were rendered tolerant by two daily sublethal doses of Salmonella enteritidis LPS, 100 micrograms/kg and 500 micrograms/kg administered intraperitoneally . Animals were allowed to rest for 72 hours . Alternatively, tolerance to LPS was induced by sublethal administration of human recombinant TNF alpha (10 micrograms/kg) intraperitoneally 24 hrs before the experiments . Macrophage membrane G protein content was determined by immunoblot analysis with specific antisera to Gi1,2 alpha, Gi3 alpha, Gs alpha and the G protein beta subunits (G beta) . Membrane G proteins were differentially decreased in tolerant macrophages . In macrophages from rats rendered tolerant by sublethal doses of LPS, Gi3 alpha was reduced the most to 48 +/- 8% of control (n = 3, P < 0.05) and this reduction was significant compared to those of other G proteins . Gi1,2 alpha and G beta were reduced to 73 +/- 5% (n = 3, P < 0.05) and 65 +/- 4% (n = 3, P < 0.05) of control respectively . Gs alpha(L) and Gs alpha(H) were also reduced to 61 +/- 5% (n = 3, P < 0.05) and 68 +/- 3% (n = 3, P < 0.05) of control, respectively . In contrast, only Gi3 alpha was reduced in macrophage membranes from rats pretreated with TNF alpha . Gi3 alpha was reduced to 57 +/- 11% of control (n = 4, P < 0.05) whereas Gi1,2 alpha and G beta were not significantly affected . These results demonstrate selective changes in tolerant macrophage membrane G proteins and suggest a potential role for Gi3 alpha in mediating LPS tolerance . The molecular mechanisms underlying these changes and their significance in LPS tolerance merit further investigation.

Infect Immun, 1998 May, 66(5), 2310 - 8
Differential early interactions between Salmonella enterica serovar Typhi and two other pathogenic Salmonella serovars with intestinal epithelial cells; Weinstein DL et al.; Salmonella enterica serovar Typhi (hereafter referred to as S . typhi) is a host-restricted pathogen that adheres to and invades the distal ileum and subsequently disseminates to cause typhoid fever in humans . However, S . typhi appears to be avirulent in small animals . In contrast, other pathogenic salmonellae, such as S . enterica serovars Typhimurium and Dublin (S . typhimurium and S . dublin, respectively), typically cause localized gastroenteritis in humans but have been used as models for typhoid fever because these organisms cause a disease in susceptible rodents that resembles human typhoid . In vivo, S . typhi has been demonstrated to attach to and invade murine M cells but is rapidly cleared from the Peyer's patches without destruction of the M cells . In contrast, invasion of M cells by S . typhimurium is accompanied by destruction of these M cells and subsequently sloughing of the epithelium . These data have furthered our view that the early steps in the pathogenesis of typhoidal and nontyphoidal Salmonella serovars are distinct . To extend this concept, we have utilized an in vitro model to evaluate three parameters of initial host-pathogen interactions: adherence of three Salmonella serovars to human and murine small intestinal epithelial cell (IEC) lines, the capacity of these salmonellae to invade IECs, and the ability of the bacteria to induce interleukin-6 (IL-6) in these cell lines as a measure of host cell activation and the host acute-phase response . The results demonstrate that S . typhi adheres to and invades human small IECs better than either S . typhimurium or S . dublin . Interestingly, invA and invE null mutants of S . typhi are able neither to adhere to nor to invade IECs, unlike S . typhimurium invA and invE mutants, which adhere to but cannot invade IECs . S . typhi also induces significantly greater quantities of IL-6 in human small IEC lines than either of the other two Salmonella serovars . These findings suggest that differential host cytokine responses to bacterial pathogens may play an important role in the pathological sequelae that follow infection . Importantly, S . typhimurium did not induce IL-6 in murine IECs . Since S . typhimurium infection in mice is often used as a model of typhoid fever, these findings suggest that, at least in this case, the mouse model does not reflect the human disease . Taken together, our studies indicate that (i) marked differences occur in the initial steps of S . typhi, S . typhimurium, and S . dublin pathogenesis, and (ii) conclusions about S . typhi pathogenesis that have been drawn from the mouse model of typhoid fever should be interpreted conservatively.

Infect Immun, 1998 May, 66(5), 2060 - 4
Delivery of the p67 sporozoite antigen of Theileria parva by using recombinant Salmonella dublin: secretion of the product enhances specific antibody responses in cattle; Gentschev I et al.; The p67 sporozoite antigen of Theileria parva has been fused to the C-terminal secretion signal of Escherichia coli hemolysin and expressed in secreted form by attenuated Salmonella dublin aroA strain SL5631 . The recombinant p67 antigen was detected in the supernatant of transformed bacterial cultures . Immunization trials in cattle revealed that SL5631 secreting the antigen provoked a 10-fold-higher antibody response to p67 than recombinant SL5631 expressing but not secreting p67 . Immunized calves were challenged with a 80% lethal dose of T . parva sporozoites and monitored for the development of infection . Two of three calves immunized intramuscularly with the p67-secreting SL5631 strain were found to be protected, whereas only one of three animals immunized with the nonsecreting p67-expressing SL5631 strain was protected . This is the first demonstration that complete eukaryotic antigens fused to the C-terminal portion of E . coli hemolysin can be exported from attenuated Salmonella strains and that such exported antigens can protect cattle against subsequent parasite challenge.

Infect Immun, 1998 May, 66(5), 1999 - 2006
Identification of epitope and surface-exposed domains of Shigella flexneri invasion plasmid antigen D (IpaD); Turbyfill KR et al.; Transport and surface expression of the invasion plasmid antigens (Ipa proteins) is an essential trait in the pathogenicity of Shigella spp . In addition to the type III protein secretion system encoded by the mxi/spa loci on the large virulence plasmid, transport of IpaB and IpaC into the surrounding medium is modulated by IpaD . To characterize the structural topography of IpaD, the Geysen epitope-mapping system was used to identify epitopes recognized by surface-reactive monoclonal and polyclonal antibodies produced against purified recombinant IpaD or synthetic IpaD peptides . Surface-exposed epitopes of IpaD were confined to the first 180 amino acid residues, whereas epitopes in the carboxyl-terminal half were not exposed on the Shigella surface . By using convalescent-phase sera from 10 Shigella flexneri-infected monkeys, numerous epitopes were mapped within a surface-exposed region of IpaD between amino acid residues 14 and 77 . Epitopes were also identified in the carboxyl-terminal half of IpaD with a few convalescent-phase sera . Comparison of IpaD epitope sequences with Salmonella SipD sequences indicated that very similar epitopes may exist in the carboxyl-terminal region of each protein whereas the IpaD epitopes in the surface-exposed amino-terminal region were unique for the Shigella protein . Although the IpaD and SipD homologs may play similar roles in transport, the dominant serum antibody response to IpaD is against the unique region of this protein exposed on the surface of the pathogen.

N Engl J Med, 1998 May 7, 338(19), 1333 - 8
Emergence of multidrug-resistant Salmonella enterica serotype typhimurium DT104 infections in the United States; Glynn MK et al.; BACKGROUND: Strains of salmonella that are resistant to antimicrobial agents have become a worldwide health problem . A distinct strain of Salmonella enterica serotype typhimurium, known as definitive type 104 (DT104), is resistant to ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline and has become a major cause of illness in humans and animals in Europe, especially the United Kingdom . METHODS: To characterize typhimurium DT104 infections in the United States, we analyzed data collected by local and state health departments and public health laboratories between 1979 and 1996 in national surveys of the antimicrobial-drug resistance of salmonella . Selected typhimurium isolates with the five-drug pattern of resistance were phage typed . RESULTS: The prevalence of typhimurium isolates with the five-drug pattern of resistance increased from 0.6 percent in 1979-1980 to 34 percent in 1996 . In 1994-1995, such isolates were identified in samples from 36 of the 46 surveillance sites (78 percent) . Thirty-nine of 43 typhimurium isolates with the five-drug pattern of resistance identified in 1994-1995 and 1996 were phage type DT104 or a closely related phage type . CONCLUSIONS: Multidrug-resistant typhimurium DT104 has become a widespread pathogen in the United States . More prudent use of antimicrobial agents in farm animals and more effective disease prevention on farms are necessary to reduce the dissemination of multidrug-resistant typhimurium DT104 and to slow the emergence of resistance to additional agents in this and other strains of salmonella.

Lett Appl Microbiol, 1998 Feb, 26(2), 131 - 5
High-resolution genotyping of Salmonella strains by AFLP-fingerprinting; Aarts HJ et al.; High resolution AFLP fingerprinting, in which subsets of genomic restriction fragments are amplified by means of PCR, was used for the identification of different . Salmonella serotypes to investigate whether this technique is applicable in epidemiological studies . Seventy-eight different Salmonella strains comprising 62 serotypes were genetically identified by AFLP . Primer combination M00 (MseI primer without additional 3' nucleotides) and E11 (EcoRI primer with two additional 3' nucleotides) resulted in reproducible profiles containing approximately 50 bands . All serotypes were characterized by a unique profile . In addition, AFLP fingerprinting enabled phage type identification . Different strains previously identified as identical, using typing methods with lower resolution, could be distinguished, showing that AFLP fingerprinting is well suited for bacterial epidemiology and identification.

Eur J Clin Invest, 1998 Mar, 28(3), 205 - 13
Different efficacy of soluble CD14 treatment in high- and low-dose LPS models; Stelter F et al.; BACKGROUND: About 50% of septic shock cases are attributed to Gram-negative bacteria or their cell wall compound lipopolysaccharide (LPS, endotoxin) . An attractive therapeutic strategy could target the binding of LPS to its cellular receptors . In vitro the soluble form of the endotoxin receptor CD14 (sCD14) competitively prevents binding of LPS to membrane-bound CD14 and inhibits LPS-stimulated macrophage responses . METHODS: We tested the in vivo endotoxin-neutralizing capacity of human recombinant sCD14 using a mouse model of shock induced by 8 micrograms g-1 of LPS from Salmonella abortus equi . RESULTS: In this model, treatment with sCD14 reduced mortality if administered before or simultaneously with LPS . However, application of sCD14 had no effect on the secretion of early proinflammatory cytokines and did not protect the animals against the development of apparent shock symptoms and liver injury . sCD14 also failed to prevent LPS-inducible (7.5 ng g-1) liver injury in galactosamine-sensitized mice . CONCLUSION: In line with these findings, sCD14 did not block LPS-induced activation of Kupffer cells in vitro, which might explain why the compound only partially protected in vivo.

Rev Sci Tech, 1997 Dec, 16(3), 891 - 7
Decontamination of chicken carcasses artificially contaminated with Salmonella; Nassar TJ et al.; A study was conducted to evaluate the efficacy of three chemical disinfectants and of ionising radiation in reducing the level of contamination in chicken carcasses which had been artificially contaminated with Salmonella Virchow . Chicken carcasses were obtained from a local abattoir . Five carcasses and one control carcass were used to test each concentration of disinfectant and the radiation . The amount of contaminant employed was 0.5 ml of 10(4) colony-forming units per ml of S . Virchow spread over the thigh, breast and wing areas . All treatments were conducted in duplicate . The three disinfectants used were as follows: calcium hypochlorite, at concentrations of 20 ppm, 50 ppm, 100 ppm and 200 ppm of available chlorine . Lactic acid at concentrations of 0.5%, 0.75% and 1% . Hydrogen peroxide compound at concentrations of 1%, 2% and 3% . Five inoculated carcasses were immersed at a time in one disinfectant concentration for 15 min, while the control carcasses were simultaneously immersed in water free from disinfectants . Five carcasses, each in a plastic bag, were subjected to varying ascending doses (from 2 to 7 k gray {kGy}) of ionising radiation from radioactive isotopes of cobalt 60 . A bacteriological examination of each carcass was conducted after the treatment to determine the presence or absence of S . Virchow . The number of carcasses which gave positive results showing the presence of Salmonella decreased after chemical treatment, but the organism was not completely eliminated . However, in those carcasses subjected to 7 kGy of radiation, Salmonella was eliminated and no changes in the appearance, colour or smell of the carcasses were observed.

Rev Sci Tech, 1997 Dec, 16(3), 885 - 90
The Swiss control programme for Salmonella enteritidis in laying hens: experiences and problems; Hoop RK; The Swiss control programme for Salmonella Enteritidis began at the end of 1993 . All efforts are focused on the elimination of infected parent and layer flocks and on the production of S . Enteritidis-free eggs . The new Zoonosis Order and more stringent import regulations help to identify S . Enteritidis-positive parent layer and layer flocks . Other measures, such as additional voluntary monitoring of parent layer flocks, hatcheries and layer flocks, increased hygiene on poultry farms and the use of heat-treated feed, serve to prevent the spread of S . Enteritidis . An important point of concern is the elimination of S . Enteritidis from contaminated poultry farms, particularly from free-range farms . In the last two years, the number of reported infections of S . Enteritidis in humans has almost fallen to the level of 1988 (the year before the onset of S . Enteritidis infection in laying hens in Switzerland).

Vaccine, 1998 Apr, 16(7), 732 - 40
LT(R192G), a non-toxic mutant of the heat-labile enterotoxin of Escherichia coli, elicits enhanced humoral and cellular immune responses associated with protection against lethal oral challenge with Salmonella spp; Chong C et al.; In the current study we examined the ability of a novel mucosal adjuvant, LT(R192G), to enhance the humoral and cellular immune responses against killed Salmonella spp . and to affect protection against lethal oral challenge with wild-type organisms . Mice orally immunized with killed S . dublin in conjunction with LT(R192G) were protected against lethal oral challenge and had higher IFN-gamma, IL-2 and IgG responses than did mice orally immunized with killed S . dublin alone which were not protected . This study demonstrates that the function of LT(R192G) in protection against typhoid-like disease is to upregulate/enhance the Th1 arm of the immune response against killed organisms . When used as a mucosal adjuvant, LT(R192G) enables the use of killed bacteria or viruses as vaccines by enhancing the overall humoral and cellular host immune response to these organisms, especially the Th1 arm of the immune response . These findings have significant implications for vaccine development and further support the potential of LT(R192G) to function as a safe, effective adjuvant for mucosally administered vaccines.

FEMS Microbiol Lett, 1998 Apr 1, 161(1), 201 - 8
Salmonella typhi rpoS mutant is less cytotoxic than the parent strain but survives inside resting THP-1 macrophages; Khan AQ et al.; Transcription of the stationary-phase sigma factor RpoS of Salmonella typhi increased in the macrophage . A single rpoS mutant of S . typhi was constructed to analyze the role of RpoS in intracellular multiplication of the bacterium and host cell killing . This mutant was sensitive to starvation, low pH and hydrogen peroxide; however, it could still multiply inside resting macrophages and was less cytotoxic than the wild-type strain . Therefore, S . typhi might produce RpoS-dependent factors which could contribute to host cell death.

FEMS Microbiol Lett, 1998 Apr 1, 161(1), 129 - 33
General transducing phages like Salmonella phage P22 isolated using a smooth strain of Escherichia coli as host; Dhillon TS et al.; A smooth colony strain, resistant to phages lambda and P22, was isolated from sewage and identified as Escherichia coli (strain H) . Four temperate phages plaquing on strain H were isolated from sewage . The archetype, HK620, does not plaque on strains C and K12 of E . coli nor on the LT2 strain of Salmonella enterica . Bacterial mutants resistant to a clear plaque mutant of HK620 produce rough colonies . Some are also galactose-negative, a few are histidine auxotrophs, and most show sensitivity to lambda . HK620 can transduce a wide variety of auxotrophic mutants of E . coli H to prototrophy . It can recombine with lambda but its virions resemble those of P22.

FEMS Microbiol Lett, 1998 Apr 1, 161(1), 75 - 82
Vi-deficient and nonfimbriated mutants of Salmonella typhi agglutinate human blood type antigens and are hyperinvasive; Miyake M et al.; We generated nonfimbriated mutants from both Vi-positive and -negative Salmonella typhi to analyze the role of type 1 fimbriae and Vi-antigen in bacterial invasion . A Vi-defective mutant of S . typhi GIFU 10007-3 was more invasive than the wild-type strain GIFU 10007 . The wild-type strain expressing Vi-antigen did not agglutinate both Saccharomyces cerevisiae and human erythrocytes but Vi-defective mutants were able to agglutinate S . cerevisiae and human erythrocytes . Nonfimbriated mutants from Vi-negative GIFU 10007-3 lost the ability to adhere to S . cerevisiae but still could agglutinate human erythrocytes . The Vi-negative mutant increased secreted proteins and became 5-fold more invasive than the wild-type strain . Nonfimbriated Vi mutants became 50-120-fold more invasive than the wild-type GIFU 10007 . To determine why nonfimbriated Vi mutants still agglutinate human red blood cells, we searched bacterial proteins that could bind human blood-type antigens . We finally identified a candidate 37 kDa outer membrane protein that recognized fucosyl-galactose, a structure common to blood type A, B and H antigens.

J Hosp Infect, 1998 Mar, 38(3), 207 - 16
Random amplification of polymorphic DNA (RAPD), pulsed-field gel electrophoresis (PFGE) and phage-typing in the analysis of a hospital outbreak of Salmonella enteritidis; Skibsted U et al.; Isolates of Salmonella Enteritidis from 81 patients from Herlev Hospital or from Copenhagen County were analysed by random amplification of polymorphic DNA (RAPD), pulsed-field gel electrophoresis (PFGE) and phage-typing . Fourteen polymorphic markers from five decamer primers unambiguously placed all isolates into six RAPD groups: 65 isolates of phagetype 6 (PFGE type I) were resolved into three RAPD groups constituting 86, 12, and 2%, respectively . A fourth RAPD group of 10 isolates was coincident with phage type 8 (PFGE type II) and two isolates, one phage-type 1, the other phage-type 4 (both PFGE type I) formed the fifth group . The sixth group of four isolates was not phage typeable and was PFGE type III . Forty outbreak-related isolates of phage-type 6 were resolved into three strains . No diversity of phage-type 6 was found among isolates unrelated to the outbreak . It is concluded that RAPD is useful as a tool in investigations of microbial outbreaks in its own right, or to supplement phage-typing and PFGE of Salmonella Enteritidis.

Antimicrob Agents Chemother, 1998 Apr, 42(4), 739 - 43
Antibiotic-induced lipopolysaccharide (LPS) release from Salmonella typhi: delay between killing by ceftazidime and imipenem and release of LPS; van Langevelde P et al.; It has been suggested that the antibiotic-induced release of lipopolysaccharide (LPS) is an important cause of the development of septic shock in patients treated for severe infections caused by gram-negative bacteria . Beta-lactam antibiotics change the integrity of the bacterial cell envelope by binding to penicillin-binding proteins (PBP) in the membrane and thus may affect the amount of LPS that is released and the kinetics of that release . In this respect, ceftazidime at intermediate concentrations binds with a high affinity to PBP 3 and PBP 1a and thus can induce filament formation in addition to killing, whereas imipenem preferentially binds to PBP 2 and PBP 1b, leading to spheroplast formation and rapid cell lysis . We investigated the effects of these antibiotics on the killing and the release of the radioactively labelled LPS of Salmonella typhi Ty 21A . A mathematical model was developed to calculate the delay between bacterial killing and LPS release, designated the lag time . At antibiotic concentrations inducing equal killing, the amount of LPS released was the same for both antibiotics . Only after 6 h of incubation at antibiotic concentrations above 0.5 microg/ml, the amount of 3H-LPS released was slightly higher (approximately 1.2-fold) in incubations with ceftazidime than in those with imipenem, and the maximum releases of the total label were 33.2% +/- 0.89% and 27.1% +/- 0.45%, respectively . Despite the clear concentration-dependent effect on the bacterial killing and subsequent LPS release, the lag time was independent of the antibiotic concentration . For ceftazidime as well as imipenem the lag time amounted to approximately 60 min . In conclusion, our findings imply that the mechanism of antibiotic-induced LPS release is independent of the PBP affinities for these beta-lactam antibiotics . Furthermore, once the organism is killed by either imipenem or ceftazidime, the rate of LPS release from S . typhi does not differ according to the antibiotic with which the organism is killed, and there is little difference in the relative amount of LPS released.

Jpn Circ J, 1998 Feb, 62(2), 139 - 41
Purulent pericarditis with tamponade caused by Salmonella enteritidis; Kiuchi K et al.; The incidence of purulent pericarditis has declined . However, mortality remains high . We describe a case of purulent pericarditis with tamponade caused by Salmonella enteritidis, and emphasize the importance of early recognition, prompt institution of appropriate antibiotic therapy, and early surgical drainage for survival.

Jpn J Thorac Cardiovasc Surg, 1998 Feb, 46(2), 231 - 5
{A case of ruptured descending thoracic aortic aneurysm due to Salmonella infection}; Tabuchi A et al.; A 66-year-old male was admitted to our hospital because of pyrexia, chest pain and hemosptum . Inflammatory findings were made and salmonella enteritidis was detected by bacterial examination of sputum and stool . Enhanced chest CT examination disclosed a descending thoracic aortic aneurysm which had ruptured into the left lower lobe of the lung . Under a diagnosis of ruptured mycotic descending thoracic aortic aneurysm, an emergency operation was performed . A left posterolateral thoracotomy carried out after axillo-bilateral femoral bypass grafting . A pseudoaneurysm of the descending thoracic aorta had ruptured into the left lower lobe of the lung . After resection of the aneurysm, closure of both ends of the intact descending thoracic aorta and a left lower lobectomy were carried out . An ascending aorta-infrarenal abdominal aorta bypass was performed because of insufficient visceral arterial blood flow through the axillo-bilateral femoral bypass . The patient's immediate postoperative recovery was complicated by paraplegia . Chloramphenicol and levofloxacin were administered for three months, after which his recovery followed a good course.

East Afr Med J, 1997 Nov, 74(11), 708 - 13
Antibiotic resistance of prevalent Salmonella and Shigella strains in northwest Ethiopia; Aseffa A et al.; Salmonella and Shigella strains were isolated prospectively from in- and outpatient specimens of the Gondar College teaching hospital over a two year period, from June 1994 to May 1996 . Of 7993 miscellaneous specimens cultured, 80 yielded Salmonella and 147 Shigella . Serogroup B dominated among the salmonella, accounting for 61% of isolates, followed by S . typhi (21%) . S . flexneri (58.5%) and S . dysenteriae (36.7%) were the most frequently isolated species among the Shigella . Results of sensitivity testing to five commonly used antibiotics in the area: ampicillin, chloramphenicol, gentamicin, tetracycline and cotrimoxazole, showed multiple drug resistance among the isolates of both salmonella and shigella . Only 4% of shigella were sensitive to all five antibiotics screened for in the study . Overall sensitive of shigella isolates to individual antibiotics was 8.8% to tetracycline, 10% to ampicillin, 28% to co-trimoxazole and 98% to gentamicin . No resistance was observed to nalidixic acid among 108 shigella strains tested for this antibiotic . The continued sensitivity of S . typhi to chloramphenicol, cotrimoxazole, ampicillin and the other commonly used antibiotics is noted . It is recommended that nalidixic acid be introduced into the area under strict regulation for treatment of severe cases of shigella dysentery, an illness which is highly endemic in the region and the cause of occasional epidemics with high mortality.

Zentralbl Veterinarmed B, 1998 Mar, 45(2), 95 - 103
A Salmonella monitoring programme in egg production farms in Germany; Geue L et al.; A programme monitoring the prevalence of Salmonella infections in egg production farms with different types of flock management was conducted over a period of 18 months . Three laying hen farms with floor pens and five farms with batteries were examined from September 1992 to March 1994 . A total of 569 samples (293 feed and 276 faeces) were processed in parallel by fivefold fractional enrichment in Rappaport/Vasiliadis medium and in potassium tetrathionate crystal violet broth . By using such elaborate methods, high detection rates of Salmonella were obtained . Two thirds of all isolates were found in the third to fifth selective enrichment procedure . Salmonella (S.) Tennessee was the most common serovar isolated (from 24.5% of the samples) whereas S . Enteritidis was the second most common isolate (23.7%) . Salmonella were isolated from 33.1% of the feed samples (97/293), a result which may stimulate further discussion on the prevention of potential contamination of feed stuff with Salmonella and other pathogens . The number of Salmonella isolations from floor pens was significantly higher than from batteries . As time progressed an increase in the number of Salmonella isolations occurred in samples taken from the floor pens . The development of a less costly routine monitoring programme to detect Salmonella in samples taken from barns with layer flocks is recommended.

J Bacteriol, 1998 Apr, 180(8), 2220 - 3
Mosaic structure of the smpB-nrdE intergenic region of Salmonella enterica; Baumler AJ et al.; The Salmonella enterica smpB-nrdE intergenic region contains about 45 kb of DNA that is not present in Escherichia coli . This DNA region was not introduced by a single horizontal transfer event, but was generated by multiple insertions and/or deletions that gave rise to a mosaic structure in this area of the chromosome.

Int J Antimicrob Agents, 1997 Jan, 9(3), 195 - 9
Inhibition of Listeria monocytogenes and Salmonella enteriditis by combinations of plant oils and derivatives of benzoic acid: the development of synergistic antimicrobial combinations; Fyfe L et al.; This study describes inhibitory properties of combinations of oil of fennel, oil of anise or oil of basil with either benzoic acid or methyl-paraben against Listeria monocytogenes and Salmonella enteriditis . Micro-organisms were cultured at 37 degrees C in broth and viable counts measured over a 48-h period . S . enteriditis was particularly sensitive to inhibition by a combination of oil of anise, fennel or basil with methyl-paraben where there was < 10 CFU/ml after 1 h . L . monocytogenes was less sensitive to inhibition by each combination however there was a significant reduction in growth of 4-8 log by combinations of all oils and methyl-paraben at 8, 24 and 48 h . Synergistic inhibition by one or more combinations was evident against each micro-organism.

Chirurg, 1998 Feb, 69(2), 204 - 6; discussion 207
{Salmonella enteritidis infected false aneurysm of the superficial femoral artery in an HIV seropositive patient}; Grotemeyer D et al.; In the course of an infection with human immunodeficiency virus, a large variety of complications affecting all organ systems can occur . However, complications affecting the vascular system demanding surgical intervention are rare . In the case presented we report a 67-year-old HIV-seropositive patient who underwent surgery for a huge abscess in the thigh . Intraoperatively unexpectedly we found a mycotic aneurysm of the femoral superficial artery and the causactive bacterium proved to be Salmonella enteritidis . Because of the rising number of HIV-infected patients we suspect that the amount of complications involving the vascular system and demanding surgical intervention will also increase . Therefore, when diagnosing and deciding on therapy for patients with AIDS, the physician must be aware that vascular complications due as a result of HIV infection might occur more frequently in the future.

Naunyn Schmiedebergs Arch Pharmacol, 1998 Mar, 357(3), 252 - 9
A therapeutic dosage of amlodipine prevents vascular hyporeactivity induced in rats by lipopolysaccharide; Salomone S et al.; The aim of this work was to investigate whether treatment with the 1,4-dihydropyridine Ca2+ antagonist amlodipine could affect the vascular hyporesponsiveness induced by cytokines . Endotoxemia was induced by Salmonella typhosa lipopolysaccharide (LPS) injection (4 mg kg(-1), i.p.) . In endothelium-denuded rings of thoracic aorta from untreated rats, contractile response to noradrenaline was decreased after LPS injection, this effect was partially overcome by the addition of N(omega)-nitro-L-arginine (L-NNA, 100 microM) into the bathing solution . In amlodipine-pretreated rats (15 mg kg(-1) day(-1), orally, for one week), the effect of LPS was lower than in untreated ones and it was completely reversed by L-NNA . The relaxation of the noradrenaline-induced tone evoked by L-arginine (10 microM) in aortae of LPS-injected rats was reduced in amlodipine-pretreated rats . Amlodipine-treatment reduced both the LPS-induced Ca2+-independent NOS activity in homogenates of heart and the expression of iNOS mRNA in aortae of LPS-injected rats . However, the vascular hyporeactivity induced by exposing aortae to interleukin-1beta in vitro was not influenced by amlodipine (10 nM) . Amlodipine (10 microM) also did not affect the production of nitrite in primary aortic smooth muscle cell culture challenged by LPS although nitrite production in macrophage culture challenged with LPS was significantly inhibited . The results show that rat pretreatment with amlodipine prevented the decrease of vascular responsiveness induced by LPS, an effect that may be at least partly related to reduction of in vivo NOS induction . The weak effect of amlodipine on the in vitro NOS induction indicates that the protective action in endotoxemia did not result from a short term interaction with L-type Ca2+ channels in vascular smooth muscle . Alternative mechanisms are discussed.

Tohoku J Exp Med, 1997 Dec, 183(4), 273 - 84
Dibutyryl cAMP inhibits endotoxin-induced increases in pulmonary vascular resistance and fluid filtration coefficient in the perfused rat lung; Takeoka M et al.; We investigated the effects of pre-treatment with dibutyryl cAMP (db-cAMP) or cGMP on endotoxin-induced hemodynamic changes and pulmonary vascular permeability in isolated perfused rat lungs . Intraperitoneal injection of Salmonella enteritidis endotoxin (2 mg/kg) caused increases in pulmonary arterial resistance (Ra) after venous reservoir elevation, in pulmonary filtration coefficient (Kf) and in lung wet-to-dry (W/D) weight ratio . Pre-treatment with db-cAMP blocked endotoxin-induced increases in Ra, Kf and W/D weight ratio . Pre-treatment with cGMP attenuated only the increase in Ra caused by endotoxin . Moreover, administration of db-cAMP 2 hours after endotoxin injection attenuated the increase in Ra induced by endotoxin treatment . The increases in Kf and W/D weight ratio caused by endotoxin were not affected by post-treatment with db-cAMP . Since the increases in Ra, Kf and W/D weight ratio caused by endotoxin were blocked by pre-treatment with db-cAMP, agents that increase intracellular cAMP level may be useful to prevent acute pulmonary vascular injury.

J AOAC Int, 1998 Mar-Apr, 81(2), 419 - 37
LOCATE enzyme-linked immunosorbent assay for detection of Salmonella in food: collaborative study; Gangar V et al.; A collaborative study was performed in 27 laboratories to validate the enzyme-linked immunosorbent procedure LOCATE for rapid detection of Salmonella in foods . Results were read visually and with a microtiter plate reader . The LOCATE method was compared with the Bacteriological Analytical Manual (BAM)/AOAC INTERNATIONAL culture method for detecting Salmonella in 6 foods: milk chocolate, nonfat dry milk, dried whole egg, soy flour, ground black pepper, and ground raw turkey . Two foods--dried whole egg and black pepper--required repeat rounds because insufficient data sets were produced initially (AOAC INTERNATIONAL stipulates a minimum of 15 sets per food type) . Each laboratory tested one or more of the 6 foods . A total of 1 439 samples were analyzed, and no significant differences (P < 0.05) were observed between LOCATE with either visual or reader detection and BAM/AOAC INTERNATIONAL results . The LOCATE screening method with visual or reader detection is recommended for Official First Action Approval.

Mutat Res, 1998 Feb 2, 397(2), 313 - 35
Induction of forward mutations at the thymidine kinase locus of mouse lymphoma cells: evidence for electrophilic and non-electrophilic mechanisms; Henry B et al.; A database of 209 chemicals tested for induction of forward mutations at the heterozygous thymidine kinase (TK +/-) locus in L5178Y mouse lymphoma cells was analyzed for structure-activity relationships using the MultiCASE expert system . Consistent with evidence of several contributing biological mechanisms, these studies suggest that such mutations may occur by more than one mechanism . As might be expected, there was evidence for a component involving direct electrophilic attack on the cellular DNA, in a manner previously established as causative in the induction of mutations in Salmonella . In addition, however, there was also strong evidence for another mechanism or mechanisms involving chromosome missegregation, cellular toxicity or an alternate site of action, such as the microtubules.

Nucleic Acids Res, 1998 Mar 15, 26(6), 1373 - 81
DNA binding and oligomerization of NtrC studied by fluorescence anisotropy and fluorescence correlation spectroscopy; Sevenich FW et al.; Fluorescence anisotropy and fluorescence correlation spectroscopy measurements of rhodamine-labeled DNA oligonucleotide duplexes have been used to determine equilibrium binding constants for DNA binding of the prokaryotic transcription activator protein NtrC . Measurements were made with wild-type NtrC from Escherichia coli and the constitutively active mutant NtrCS160Ffrom Salmonella using DNA duplexes with one or two binding sites . The following results were obtained: (i) the dissociation constant K d for binding of one NtrC dimer to a single binding site was the same for the wild-type and mutant proteins within the error of measurement . (ii) The value of K d decreased from 1.4 +/- 0.7 x 10(-11) M at 15 mM K acetate to 5.8 +/- 2.6 x 10(-9) M at 600 mM K acetate . From the salt dependence of the dissociation constant we calculated that two ion pairs form upon binding of one dimeric protein to the DNA . (iii) Binding of two NtrC dimers to the DNA duplex with two binding sites occured with essentially no cooperativity . Titration curves of NtrCS160Fbinding to the same duplex demonstrated that more than two protein dimers of the mutant protein could bind to the DNA.

Schweiz Rundsch Med Prax, 1998 Feb 25, 87(9), 318 - 21
{Febrile state, bloody diarrhea and megacolon}; Hellermann J et al.; We report about a forty year old female patient with severe bloody diarrhoea and fever over a period of 14 days due to an infection with Salmonella enteritidis . X-ray of the abdomen showed a toxic megacolon . With the diagnosis of an infectious colitis we started therapy with ciprofloxacin i/v . The toxic megacolon progressed despite intensive care and parenteral nutrition . Additionally the patient received metronidazole i/v and in combination with a roll technique in bed in the knee-elbow-position the leucocytosis and the megacolon decreased . A toxic megacolon is in about 3% associated with an infection with Salmonella enteritidis . It is essentially diagnosed by X-ray . Patients should receive intensive care, and because of the high mortality rate an interdisciplinary management is required . The article discusses the major differential diagnosis of the toxic megacolon, as well as the pathogenesis and therapy of Salmonella ent, infection . In case of an infection with Salmonella ent . physicians should acknowledge the possibility of development of a toxic megacolon.

Environ Mol Mutagen, 1998, 31(2), 169 - 75
Comparative studies of the mutagenicity of environmental tobacco smoke from cigarettes that burn or primarily heat tobacco; Bombick BR et al.; The mutagenicity of particulate matter concentrated from environmental tobacco smoke (ETS) from a prototype cigarette that primarily heats tobacco was compared to that of four popular commercially available cigarettes that burn tobacco . ETS was generated by six individuals simultaneously smoking 1 cigarette each in a 20-min time period in a 45 m3 environmental chamber operated in the static mode (without ventilation) . Respirable suspended particles (RSP) were collected on polytetrafluoroethylene (PTFE) filters at a flow rate of 3 LPM for 120 min . Less ETS-RSP (86-90%) was emitted by the prototype tobacco-heating cigarette than by the tobacco-burning cigarettes . RSP was extracted from the filters by sequential sonication in acetone and dichloromethane . The acetone extract was dried under nitrogen and the dichloromethane filtrate was added and then dried to obtain ETS-RSP for testing . Mutagenicity was assessed in the microsuspension modification of the Ames Salmonella/microsome assay with strains TA98 and YG1024 in the presence of 5% S9 metabolic activation . The results show that the mutagenic activity of RSP from the prototype cigarette was reduced by 75-83% on a per-mg basis when compared to the commercially available cigarettes and was reduced by 96-98% when calculated as revertants/m3 air under identical smoking conditions.

J Ultrasound Med, 1998 Apr, 17(4), 231 - 7
Sonographic analysis of gallbladder findings in Salmonella enteric fever; Shetty PB et al.; The purpose of this study was to analyze gallbladder sonographic findings associated with Salmonella typhi enteric fever . Sixty-two patients with culture positive Salmonella enteric fever were analyzed with serial sonography . The following gallbladder sonographic findings were noted: globular gallbladder distention (33 of 62 patients, 530%), positive sonographic Murphy sign (25 patients, 40%), pericholecystic edema or fluid (25 patients, 40%), gallbladder wall thickening > 4 mm (21 patients, 34%), low-level nonshadowing intraluminal echoes or sludge (nine patients, 15%), intramural linear sonolucency or striation (eight patients, 13%), and mucosal irregularity or sloughed membrane (four patients, 6%) . Using the sonographic findings a gallbladder score was devised to assess the severity of gallbladder changes, and the score was correlated with the following clinical parameters--duration of fever, multidrug resistance, and clinical outcome . An abnormal gallbladder score was noted in 37 patients (60%), and multidrug resistance was noted in 35 of these patients (95%) . The gallbladder scores showed a strong positive correlation with the duration of fever and the frequency of multidrug resistance . All 62 patients were treated with intensive antibiotic therapy without any deaths.

Arch Pediatr, 1997 Dec, 4(12), 1175 - 81
{Salmonella meningitis in children in Libreville . Retrospective study of 9 cases}; Koko J et al.; BACKGROUND: Salmonella meningitis is a rare entity, even in tropical area where salmonellosis is common . Its prognosis is poor and the choice of adequate antibiotic therapy is difficult . PATIENTS AND METHODS: The files of nine children (three boys, six girls) admitted to the pediatric unit of the Owendo Pediatric Hospital in Libreville for salmonella meningitis between January 1, 1989, and December 31, 1993 were retrospectively studied . Diagnosis was established by a positive culture of cerebrospinal fluid . RESULTS: Salmonella was the third cause (8.65%) of purulent meningitis observed during this period . Eight children were less than 1-year old, seven were from low socioeconomic standard families . The main clinical manifestations were fever (seven cases), pallor (six cases), diarrhea (four cases), nuchal rigidity (four cases), convulsions (three cases) and bulging fontanel (three cases) . Five children (55.5%) were severely anemic (hemoglobin < 5 g/dL) but none had abnormal hemoglobin . Serotyping could not be performed in any case . Salmonella isolates were resistant to chloramphenicol in six cases and to ampicillin in five . Cefotaxime (200 mg/kg/24 h intravenously in three divided doses) was given to seven patients . The duration of therapy was at least 3 weeks in four patients . There were five deaths at ages ranging from 1 to 12 months, ie, a case fatality rate of 55.5% . Three patients (33.3%) recovered with neurological sequels . CONCLUSION: The prognosis of salmonella meningitis is poor, even in the case of prompt diagnosis and adequate therapy . Preventive measures only can decrease the risk of illness in children.

Ir J Med Sci, 1998 Jan-Mar, 167(1), 19 - 21
Bacterial toxin-induced pulmonary epithelial cytotoxicity and the protective effect of dibutyryl-cAMP; Bourke W et al.; Bacterial infection is the most common cause of the adult respiratory distress syndrome which, in turn is associated with endothelial capillary permeability and alveolar oedema . Previously, we have demonstrated the direct cytotoxicity of the bacterial toxins Pseudomonas aeruginosa exotoxin A (Exo A) and Salmonella enteritidis lipopolysaccharide (LPS) on pulmonary endothelial cells . The purpose of this study was to investigate the effect of Exo A and LPS on pulmonary epithelial cells in vitro . We also tested the protective effect of dibutyryl cyclic adenosine monophosphate (db-cAMP) on Exo A-induced cytotoxicity . In cultured rat alveolar epithelial cells (RAEC) Exo A caused cytotoxicity as measured by 51Cr release from these cells . LPS did not injure RAEC's . Pretreatment of RAEC with db-cAMP (1 mM) attenuated Exo A induced cytotoxicity . We conclude that (1) Exo A directly injures epithelial lung cells and may contribute to lung injury in cases of bacterial infection; (2) db-cAMP protects alveolar epithelial cells against Exo A-induced cytotoxicity and (3) alveolar epithelial cells in this model are resistant to LPS induced injury.

Mutat Res, 1998 Jan 30, 412(2), 167 - 75
Studies on the effect of the solvents dimethylsulfoxide and ethyleneglycoldimethylether on the mutagenicity of four types of diisocyanates in the Salmonella/microsome test; Herbold B et al.; The mutagenicity of isomers and homologs of diphenylmethanediisocyanate (4,4'-diisocyanatodiphenylmethane, 2,4'-diisocyanatodiphenylmethane, a mixture of monomeric MDI isomers, and polymeric MDI), containing 55-100% of monomeric MDI, was determined in the Salmonella/microsome test using dimethylsulfoxide (DMSO) and ethyleneglycoldimethylether (EGDE) as solvents . Positive results were obtained for DMSO solutions of all four diisocyanates in the presence of S9 mix containing 30% S9 fraction . Uniformly negative results were found when the diisocyanates were dissolved in EDGE . These results correspond to those of analytical investigations . A small amount of diaminodiphenylmethane (MDA) is one of the reaction products formed when MDI is dissolved in commercial DMSO . No MDA could be detected in solutions of MDI in EGDE . It is therefore concluded that the positive results obtained with diisocyanates in DMSO solutions are due to the formation of MDA . This is artificially formed through the hydrolysis of MDI, caused by traces of water that are always present in DMSO . These findings indicate that DMSO is an inappropriate solvent and should therefore not be used in any in vitro study with diisocyanates . EGDE may be a suitable replacement . The positive test results reported so far for DMSO solutions of MDI are thus only of limited relevance for risk evaluation.

Mutat Res, 1998 Jan 30, 412(2), 145 - 54
Laser pyrolysis products: sampling procedures, cytotoxic and genotoxic effects; Stocker B et al.; The use of lasers in medical applications has grown enormously in the last few years . Recent chemical analysis of the laser pyrolysis products revealed that aerosols generated by pyrolytic decomposition of tissue could be health hazards . Therefore we analysed the genotoxic and mutagenic effects of laser pyrolysis products from different types of porcine tissue . The tissues were irradiated with a surgical CO2 laser and the generated aerosols were sampled as particulate fractions as well as low and highly volatile fractions . Then human leukocytes were incubated with the pyrolysis products and subjected to the comet assay . The results of the comet assay indicated the pyrolysis products being inducers of DNA damage . The ability to induce genotoxic effects turned out to be strongly dependent on the type of tissue that had been irradiated during laser treatment . To check whether the pyrolysis products also have mutagenic properties the Salmonella mutagenicity assay was performed . The particulate aerosol fractions of skin, muscle tissue and liver tissue clearly proved to be mutagenic in TA98 in the presence of S9 mix . There was no mutagenic effect detectable without metabolic activation . In conclusion, our experiments showed that the laser pyrolysis products originating from porcine tissues induced very potent genotoxic as well as mutagenic effects and therefore they could be potential health hazards for humans.

Mutat Res, 1998 Jan 30, 412(2), 115 - 30
Comparison of responses of base-specific Salmonella tester strains with the traditional strains for identifying mutagens: the results of a validation study; Gee P et al.; The ability of a TA7000 series of Salmonella his- mutant tester strains to detect mutagens as classified by the traditional tester strains (TA100, TA98, TA1535, TA1537, TA97, TA102 and TA104) was evaluated using 30 coded chemicals, 5 of which were duplicates with different code numbers . The TA7000 series of tester strains were TA7001, TA7002, TA7003, TA7004, TA7005 and TA7006, each of which reverts by a specific base substitution . In addition, each chemical was tested in a mixture of the base-specific strains (the Mix), plus the traditional strains, TA98 and TA1537 . A liquid version of the Salmonella mutagenicity assay was performed in microtiter plates to allow partial automation for increased throughput . The results were compared to those in the National Toxicology Program (NTP) database, which were obtained from the traditional strains in the preincubation assay . In the two strains common to both protocols, TA98 and TA1537, the agreement was 80% and 85%, respectively . When compared to the NTP results for TA100, the Mix gave a 72% concordance, while the addition of the frameshift tester strain, TA98, increased the agreement to 76% . The overall agreement on positive or negative classifications of mutagenicity was 88% for the 25 chemicals tested . There were three notable exceptions to the overall agreement . Benzaldehyde was detected as a mutagen in TA7005 in contrast to its classification as a non-mutagen in the NTP database . This does not necessarily contradict the NTP results because the base-specific strains may respond to different mutagens . Two weak mutagens in the NTP database, 1-chloro-2-propanol and isobutyl nitrite, were not detected as mutagens in the base-specific new strains in the liquid protocol . While there are a number of major differences in the two assays, it was concluded that the results from each procedure are comparable.

Cell Mol Life Sci, 1998 Feb, 54(2), 143 - 7
Specific recombinogenic activity of a new polyene antibiotic; Vachkova R et al.; A new antibiotic from Streptomyces sp., tetrapol A159, active against various fungi, a promising compound for the control of plant diseases, was studied for its genotoxic effects . It was produced at the Institute of Microbiological Preparations for Agriculture, Sofia, Bulgaria . The chemical was tested in three different test systems: a bacterial system, the Ames test for point mutations, the micronucleus test in bone marrow cells of rats for chromosomal aberrations and the fungal system of Aspergillus nidulans for mitotic recombination and aneuploidy . No increase in histidine revertants was observed in any of the TA100, TA98, TA1535 and TA1537 strains of Salmonella at concentrations ranging from 1 to 4000 mg/plate . The results were also negative in the micronucleus test of bone marrow cells at concentrations from 124 to 600 mg/kg b.w., whereas a statistically significant threefold increase of mitotic crossovers was found in Aspergillus, at concentrations from 0.5 to 2.5 mg/ml.

Rev Sci Tech, 1997 Apr, 16(1), 83 - 90
{The risk of transmission of salmonellae in poultry farming: detection and prevention in Europe}; Humbert F et al.; While salmonellas can cause disease problems among poultry, they remain essentially a concern for public health, as a cause of outbreaks of food poisoning . The principal site of multiplication of these bacteria is the digestive tract, particularly the caecum, which may result in widespread contamination of the environment . The pathogenicity of salmonellas depends on the invasive properties and the ability of the bacteria to survive and multiply within cells, particularly macrophages . These properties are the source of vertical transmission which, in the case of survival of the embryo, can result in contamination of a flock or, in the case of embryonic mortality, can result in an explosion of contaminated eggs . Salmonella infection can be diagnosed by isolating the bacteria and/or serological testing of the flock . European Union Directive 92/117/EC, modified by Directive 97/22/EC, stipulates either the destruction of infected flocks of breeding birds, or decontamination of the flock in an effective way, before normal trade in products can be resumed . Noteworthy examples of effective measures suitable for prophylaxis of Salmonella infection in poultry flocks include the slaughter of infected breeding stock, the creation of sanitary barriers at building entrances, heat treatment of feed, the use of competitive exclusion, selection of breeds genetically resistant to Salmonella, and occasional vaccination and antibiotic treatment . However, the most effective means of reducing food poisoning remains adequate cooking of food and maintenance of the cold chain.

Tijdschr Diergeneeskd, 1998 Feb 15, 123(4), 114 - 7
{Pustular dermatitis in veterinarians following delivery in farm animals; an occupational disease}; Visser IJ; OBJECTIVE: To assess the prevalence of contact dermatitis after deliveries in cattle or sheep among veterinarians . DESIGN: Retrospective . SETTING: Provinces of Groningen, Friesland, and Drenthe, The Netherlands . METHODS: By means of a short inquiry 310 veterinarians were asked whether and how often they had experienced pustular dermatitis after deliveries in cattle and sheep and what course the dermatitis had run . They were also asked about details of the deliveries (type of animal, condition of the foetus, course of the partus), about microbiological investigation, preventive measurements and therapy . RESULTS: The response to the questionnaires was 24.5% . One or more episodes of pustular dermatitis on an arm after a delivery in cattle or sheep was noticed by 62 (81.5%) of the 76 respondents . Sometimes it was associated with secondary symptoms like headache, fever and lymphadenitis . Listeria monocytogenes (7 times out of 13) and Salmonella dublin (4/13) were the agents cultured most often . CONCLUSION: Contact dermatitis after deliveries in cattle or sheep occurs frequently as an occupational disease of veterinarians.

Eur Radiol, 1998, 8(2), 295 - 7
Mycotic aneurysm rupture of the descending aorta; Gufler H et al.; A 69-year-old diabetic male with salmonella bacteremia developed hypovolemic shock and swelling of the neck . A CT examination revealed massive mediastinal hemorrhage extending into the neck soft tissues caused by false aneurysm rupture of the descending thoracic aorta . Aortography showed continuous extravasation from a large leak at the medial side of the descending thoracic aorta . Although surgical intervention was immediately performed, the patient died 3 weeks later from multiple-organ failure . In this report, CT and angiographic findings of mycotic aneurysm rupture are presented and a review is given.

J Ethnopharmacol, 1998 Feb, 60(1), 79 - 84
Antibacterial activity of East African medicinal plants; Fabry W et al.; In an ethnopharmacological survey, extracts of the six East African medicinal plants Entada abyssinica (stem bark), Terminalia spinosa (young branches), Harrisonia abyssinica (roots), Ximenia caffra (roots), Azadirachta indica (stem bark and leaves), and Spilanthes mauritiana (roots and flowers) were tested against 105 strains of bacteria from seven genera (Staphylococcus, Enterococcus, Pseudomonas, Escherichia, Klebsiella, Salmonella, Mycobacterium) . The minimum inhibitory concentration reached by 50% (MIC50%) and 90% (MIC90) of the strains for the extracts of E . abyssinica, T . spinosa, X . caffra, and A . indica (stem bark) ranged from 0.13-8 mg/ml and from 0.5 to > 8 mg/ml, respectively . Their minimum bactericidal concentration by 50% (MBC50%) and MBC90% were all between 0.5 and > 8 mg/ml . H . abyssinica, A . indica (leaves), and S . mauritiana (roots and flowers) had MIC and MBC values > or = 8 mg/ml . Mycobacteria were not inhibited at extract concentrations of 0.5-2 mg/ml . It is concluded that plant extracts with low MIC and MBC values may serve as sources for compounds with therapeutic potency.

Vet Immunol Immunopathol, 1997 Dec 12, 60(1-2), 111 - 30
Analysis of the immune response in sheep efferent lymph during Salmonella abortusovis infection; Gohin I et al.; The efferent lymph duct of the ovine prescapular lymph node was cannulated, and Salmonella abortusovis (SAO), a specific pathogen for sheep inducing abortion and mortality of newborn lambs, was inoculated by the subcutaneous route in this lymph node drained area . While the prescapular lymph node draining the inoculation site represented an efficient barrier for the vaccinal SAO Rv6 strain spreading, SAO 15/5 virulent bacteria were steadily detected in efferent lymph of infected sheep . The inoculation of the virulent strain of SAO induced a greater increase of the cell output than did the attenuated vaccinal strain, but proportions of blast cells appearing in the efferent lymph were similar in both cases . Flow cytometry analysis showed that B and T cell outputs were both increased during SAO infections, but while T cell subset proportions slightly decreased, B cell percentages significantly rose, and, at the peak response, almost all of the lymphoblast cells were activated B cells . Typical antibody profiles characteristic of a primary immune response were observed, and antibody titres were greater in the efferent lymph of animals inoculated with the virulent strain of SAO . Many of the cytokine mRNAs we investigated were steadily detected by RT-PCR in efferent lymph cells of control sheep, but frequencies of detection of IL-2, IFN gamma, IL-1 beta and TNF alpha mRNAs were augmented in efferent lymph cells following inoculation of both SAO virulent or vaccinal strains . IL-10 and IL-8 mRNAs could only be detected after a SAO inoculation, while detection of IL-4 mRNAs was increased only in efferent lymph cells from SAO virulent strain-infected sheep . The efferent lymph cannulation technique thus appeared a very powerful way to study the in vivo development of the immune response to SAO, in its natural host, the sheep.

Avian Dis, 1998 Jan-Mar, 42(1), 146 - 53
Mutation rate of avian intestinal coliform bacteria when pressured with fluoroquinolones; Medders WM et al.; The purpose of this study was to determine the rate at which resistance developed in avian coliform bacteria when exposed to nalidixic acid, sarafloxacin, or enrofloxacin . In in vitro studies, the rates of mutation of avian isolates of Escherichia coli and Salmonella were determined following nalidixic acid, sarafloxacin, or enrofloxacin pressure . The rates of mutation were similar for nalidixic acid and sarafloxacin, whereas a lower rate of mutation was seen after enrofloxacin pressure . In in vivo studies, the quinolones were administered in the drinking water to broiler chickens at a concentration of 40 ppm for five consecutive days . Samples of feces were inoculated onto appropriate media and the frequency of resistance was determined . The frequency rates of resistance to nalidixic acid and sarafloxacin were similar . Enrofloxacin-medicated birds did not develop enrofloxacin-resistant coliform bacteria . The in vitro and in vivo data appear to correlate.

Avian Dis, 1998 Jan-Mar, 42(1), 67 - 71
A survey for Salmonella by drag swabbing manure piles in California egg ranches; Riemann H et al.; A cross-sectional study was conducted between August 1995 and November 1996 . Sixty California egg-producing ranches were chosen at random; 39 ranches agreed to participate in the study . The surface of the manure pile in one house on each ranch was sampled by drag swabbing . The drag swabs were tested for Salmonella using a most probable number procedure that had a detection level of one to five Salmonella per drag swab . In 12 ranches (32.4%), the drag swabs were negative for Salmonella; the remaining had Salmonella counts in the range of 1 to over 1700 per swab . Twenty-two different serotypes were found . Salmonella heidelberg and Salmonella cerro represented the majority of the typed isolates . Salmonella enteritidis (SE) was found on only one ranch . This study found SE to be rare in California egg ranches, which implies that these ranches are not a major source of S . enteritidis.

Avian Dis, 1998 Jan-Mar, 42(1), 45 - 52
Airborne horizontal transmission of Salmonella enteritidis in molted laying chickens; Holt PS et al.; Salmonella enteritidis is currently thought to be transmitted principally through contact with infected individuals and ingestion of fecally contaminated materials . The present study was undertaken to determine if S . enteritidis could be spread in chickens by the airborne route and if induced molting could affect this mode of transmission . To test for airborne transmission, hens were placed in two rows of cages, the rows separated from each other by 1 m . One row of hens was challenged with S . enteritidis, whereas the other row remained unchallenged but exposed to the room air . Ventilation delivered within the room provided an even air distribution within the area and minimized directional air flow toward any set of cages . In Expt . 1, 4 of 12 and 9 to 12 exposed molted hens became infected with S . enteritidis after 3 and 8 days of exposure, respectively, compared with 1 of 12 and 0 of 12 unmolted hens sampled on the same days . Similar S . enteritidis levels were detected circulating in the air in the two rooms housing the hens . Expts . 2 and 3 examined airborne transmission in molted hens only . In Expt . 2, 2 of 12 exposed hens became infected with S . enteritidis at 3 days postchallenge, and this increased to 12 of 12.1 wk later . In Expt . 3, exposed hens were again housed in cages 1 m from challenged hens but were placed in every other cage to prevent transmission through contact with hens in adjacent cages . At day 3 post challenge, 0 of 12 exposed hens were culture positive for S . enteritidis, and this increased to only 3 of 10 positive hens at day 10 . Large numbers of S . enteritidis shed by the molted challenged hens were recovered from the floors beneath the cages . These results indicated that, contrary to the generally held beliefs regarding organism spread, airborne transmission of S . enteritidis can occur and induced molting can provide the impetus for this event . As was observed previously, rapid dissemination of the organism to other members of the flock resulted through bird-to-bird contact.

Vet Clin North Am Food Anim Pract, 1998 Mar, 14(1), 151 - 64
Pathogen Reduction and Hazard Analysis and Critical Control Point (HACCP) systems for meat and poultry . USDA; Hogue AT et al.; The United States Department of Agriculture (USDA) Food Safety Inspection Service (FSIS) adopted Hazard Analysis and Critical Control Point Systems and established finished product standards for Salmonella in slaughter plants to improve food safety for meat and poultry . In order to make significant improvements in food safety, measures must be taken at all points in the farm-to-table chain including production, transportation, slaughter, processing, storage, retail, and food preparation . Since pathogens can be introduced or multiplied anywhere along the continuum, success depends on consideration and comparison of intervention measures throughout the continuum . Food animal and public health veterinarians can create the necessary preventative environment that mitigates risks for food borne pathogen contamination.

Afr J Med Med Sci, 1996 Dec, 25(4), 373 - 5
Antimicrobial activity of some medicinal plants extracts on Escherichia coli, Salmonella paratyphi and Shigella dysenteriae; Omoregbe RE et al.; The antimicrobial activity of three plants extracts--Momordica charantia, Alstonia boonei, and Ocimum bacilicum on pure and viable cultures of Escherichia coli, Salmonella paratyphi and Shigella dysenterae was examined . Cold maceration method of extraction using 95% ethanol was used for the extraction of the active constituents of the leaves . Filter paper disks which were 6 mm in diameter were used for sensitivity testing . Results showed that the extracts from the leaves of the three plants have some antimicrobial properties against the test organisms which suggest their future possible commercial therapeutic use, although this is a preliminary study.

Zentralbl Hyg Umweltmed, 1998 Feb, 200(5-6), 531 - 41
{Mutagenicity of mixtures of halogenated aliphatic hydrocarbons and polycyclic aromatic hydrocarbons in the Ames test with TA98 and TA100}; Kevekordes S et al.; Within the framework of the assessment of the genotoxic potential of environment samples the Salmonella-microsome-test (Ames-test) is often used as a screening-test . It is one of the most applied biotest systems and possesses a large scientific acceptance . Because most environment samples are mixtures of various substances, possible effects resulting from the combination should be taken into account with regard to the mutagenic potential . In this context we investigated eight polycyclic aromatic hydrocarbons each combined with six halogenated aliphatic hydrocarbons as to their mutagenicity in the Salmonella-microsome-test with TA98 and TA100 . For an exogenous metabolizing system, Arochlor 1254 induced rat liver S9-mix was used . Benz-a-pyrene in combination with bromodichloromethane (Ames neg . in TA98 and TA100 +S9) showed an increase in the number of the revertants up to 25% in TA98 and TA100 (+S9) . Carbon tetrachloride (Ames neg . in TA98 and TA100 +S9) showed in TA100 (+S9) an increase in the number of the revertants of 18% at most . In the combination 3-methylcholanthrene with dichloromethane the number of revertants in TA98 (+S9) increased by 25% and in TA100 (+S9) by 18% . Hexachloroethane (weakly mutagenic in TA98 +S9) in combination showed in TA98 (+S9) a slightly increased number of revertants with benz-a-pyrene as well with 3-methylcholanthrene . All the other substances tested (chrysene, phenanthrene, anthanthrene, dibenz-a, i-pyrene, triphenylene, fluoranthene) in combination with either tetrachloroethylene or trichloroethene did not cause an increase in mutagenicity.

J Immunol, 1998 Apr 1, 160(7), 3480 - 6
Activation of caspase 3 (CPP32)-like proteases is essential for TNF-alpha-induced hepatic parenchymal cell apoptosis and neutrophil-mediated necrosis in a murine endotoxin shock model; Jaeschke H et al.; Endotoxin (ET)-induced liver failure is characterized by parenchymal cell apoptosis and inflammation leading to liver cell necrosis . Members of the caspase family have been implicated in the signal transduction pathway of apoptosis . The aim of this study was to characterize ET-induced hepatic caspase activation and apoptosis and to investigate their effect on neutrophil-mediated liver injury . Treatment of C3Heb/FeJ mice with 700 mg/kg galactosamine (Gal) and 100 microg/kg Salmonella abortus equi ET increased caspase 3-like protease activity (Asp-Val-Glu-Asp-substrate) by 1730 +/- 140% at 6 h . There was a parallel enhancement of apoptosis (assessed by DNA fragmentation ELISA and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay) . In contrast, activity of caspase 1 (IL-1beta-converting enzyme)-like proteases (Tyr-Val-Ala-Asp-substrate) did not change throughout the experiment . Caspase 3-like protease activity and apoptosis was not induced by Gal/ET in ET-resistant mice (C3H/HeJ) . Furthermore, only murine TNF-alpha but not IL-1alphabeta increased caspase activity and apoptosis . Gal/ET caused neutrophil-dependent hepatocellular necrosis at 7 h (area of necrosis, 45 +/- 3%) . Delayed treatment with the caspase 3-like protease inhibitor Z-Val-Ala-Asp-CH2F (Z-VAD) (10 mg/kg at 3 h) attenuated apoptosis by 81 to 88% and prevented liver cell necrosis (< or = 5%) . Z-VAD had no effect on the initial inflammatory response, including the sequestration of neutrophils in sinusoids . However, Z-VAD prevented neutrophil transmigration and necrosis . Our data indicate that activation of the caspase 3 subfamily of cysteine proteases is critical for the development of parenchymal cell apoptosis . In addition, excessive hepatocellular apoptosis can be an important signal for transmigration of primed neutrophils sequestered in sinusoids.

Epidemiol Infect, 1998 Feb, 120(1), 29 - 35
A community outbreak of Salmonella berta associated with a soft cheese product; Ellis A et al.; In September 1994, a complaint was registered at a public health unit concerning a cheese product . In addition, public health laboratories in Ontario reported an increase in the number of isolates of Salmonella berta from patients with diarrhoeal illness . A clinical, environmental and laboratory investigation was initiated to determine the nature of this outbreak . Isolates of Salmonella berta were compared using large fragment genomic fingerprinting by pulsed-field gel electrophoresis (PFGE) . By late October, 82 clinical cases had been identified including 35 confirmed, 44 suspected and 3 secondary . The investigation linked illness to consumption of an unpasteurized soft cheese product produced on a farm and sold at farmers' markets . Subtyping results of patient, cheese and chicken isolates were indistinguishable, suggesting that the cheese was contaminated by chicken carcasses during production . The outbreak illustrates the potential role of uninspected home-based food producers and of cross-contamination in the transmission of foodborne bacterial pathogens.

Arch Microbiol, 1998 Feb, 169(2), 113 - 9
Effects of the insertion of a nonapeptide from murine IL-1beta on the immunogenicity of carrier proteins delivered by live attenuated Salmonella; Chen I et al.; A nonapeptide from IL-1beta has been reported to be an immunostimulant and adjuvant . To investigate the possibility of enhancing the immunogenicity of recombinant antigens delivered by live-attenuated Salmonella strains, we inserted an oligonucleotide coding for the nonapeptide from murine IL-1beta into the genes of three model proteins: LamB, MalE, and flagellin . The hybrid proteins were expressed and delivered in vivo by Salmonella aroA strains, and serum antibody responses were analyzed . The results showed that the nonapeptide induced an increase in the immune response against Salmonella-delivered flagellin, measured on day 28 post-immunization . However, the adjuvant effect was lost by day 42 . In no case was an adjuvant effect detected for Salmonella-delivered LamB or MalE . Thus, by comparing the immune responses raised by purified MalE with and without the peptide, we investigated whether the insertion of the peptide affected the immunogenicity of the protein itself . Also in this case, a modest adjuvant effect was shown only after primary immunization and when very low doses of antigen were used . In conclusion, the immunomodulatory properties of the IL-1beta peptide can also be detected when it is delivered in vivo by Salmonella; however, the effect is modest and antigen-dependent.

J Biochem Mol Toxicol, 1998, 12(3), 143 - 9
Streptozotocin may provide protection against subsequent oxidative stress of endotoxin or streptozotocin in rats; Omar HM et al.; Endotoxin lipopolysaccharide (LPS) and streptozotocin-induced diabetes are known to cause oxidative stress in vivo . There is some evidence that a sublethal dose of LPS provides protection against subsequent oxidative stress . Because of its wide use as a diabetogenic agent, this study was undertaken to determine if streptozotocin can likewise provide a protective effect against further oxidative stress in rats . Female Sprague-Dawley rats were given streptozotocin (50 mg/kg intraperitoneally once) prior to exposure to either bacterial endotoxin from Salmonella abortus equii (5 mg/kg intraperitoneally) or three additional daily doses of streptozotocin (50 mg/kg intraperitoneally) . One week after LPS or streptozotocin treatments, oxidative stress was determined by measuring changes in antioxidant activity (glutathione peroxidase, glutathione reductase, superoxide dismutase, catalase, glutathione S-transferase, and gamma-glutamyltranspeptidase) and in concentrations of glutathione, nitrite, and thiobarbituric acid reactants in liver, kidney, intestine, and spleen . High levels of some antioxidants in the LPS-control and streptozotocin-control rats, in contrast to normal levels found in diabetes + LPS and multidose-streptozotocin rats, suggest that streptozotocin, like LPS, may confer a protective effect against subsequent oxidative stress.

J Reconstr Microsurg, 1998 Jan, 14(1), 13 - 6
Free vascularized fibular graft in the treatment of Salmonella typhi osteomyelitis of the distal radius; Taniguchi Y et al.; The authors report a rare case of Salmonella typhi osteomyelitis involving the distal radius . The patient was treated successfully by wide resection and reconstruction of the distal radius with a vascularized fibular transfer . Local recurrence of infection did not occur . The free vascularized fibular graft is an effective procedure for the treatment of osteomyelitis of the distal radius.

J Zoo Wildl Med, 1997 Dec, 28(4), 368 - 77
Health evaluation of free-ranging and hand-reared macaws (Ara spp.) in Peru; Karesh WB et al.; As part of ongoing ecological studies and reproduction enhancement efforts for macaws in southwestern Peru, a health survey of parent- and hand-reared scarlet macaws (Ara macao) and blue and gold macaws (Ara ararauna) was conducted in 1994 . Thirty-three birds were examined during handling procedures, and blood samples were collected from 27 (9 parent reared, 18 hand reared) for laboratory analysis . All but one bird appeared to be in good condition, with no abnormality noted during physical examination . Hematology, plasma chemistries, and plasma vitamin and mineral levels were studied and correlated with the results of bacterial and viral serology . Positive antibody titers for Salmonella and psittacine herpesvirus were found . These diseases have the potential to affect wildlife population dynamics, and Salmonella may have public health significance . Serological tests for avian influenza, infectious laryngotracheitis, paramyxovirus-1, -2, -3, polyoma virus, chlamydiosis, and aspergillosis were negative . Differences in disease prevalence were found between rearing situations.

P N G Med J, 1995 Dec, 38(4), 325 - 31
A review of the current status of enteric vaccines; Levine MM et al.; Much progress has been made in developing vaccines against the most important enteric infections . Two new vaccines against typhoid fever (oral Ty21a and parenteral Vi polysaccharide) have been licensed in many countries . Newer, more sophisticated typhoid vaccines undergoing clinical testing include recombinant attenuated Salmonella typhi strains and Vi polysaccharide-carrier-protein conjugate vaccines . Two inactivated oral cholera vaccines, consisting of inactivated Vibrio cholerae O1 bacteria alone or in combination with B subunit of cholera toxin, each conferred 50-53% protection over three years in a field trial in Bangladesh where subjects were immunized with a three-dose regimen . An engineered live oral cholera vaccine, strain CVD 103-HgR, has been shown in extensive clinical trials to be well tolerated by children and adults in less developed countries and highly immunogenic following administration of just a single oral dose; a large-scale field trial of the efficacy of this vaccine is underway . In experimental challenge studies in volunteers, a single dose of CVD 103-HgR confers significant protection against challenge with wild-type V . cholerae O1 of either classical or El Tor biotype and either Inaba or Ogawa serotype . Several candidate vaccines against Shigella and enterotoxigenic Escherichia coli are in clinical trials . A multivalent rotavirus vaccine (rhesus reassortant vaccine) is undergoing extensive field testing in developed and less developed countriesPIP: The development of safe, effective vaccines to prevent diseases due to rotavirus, enterotoxigenic Escherichia coli, enteropathogenic E . coli, Shigella, and Vibrio cholerae O1 would markedly reduce the burden of diarrheal diseases in Third World countries . This review concentrates on vaccines that have already been licensed, that have been evaluated in controlled trials of efficacy, or that have entered clinical trials to assess their safety and immunogenicity . Two new vaccines against typhoid fever have been licensed . Newer, more sophisticated typhoid vaccines undergoing clinical testing include recombinant attenuated Salmonella typhi strains and Vi polysaccharide-carrier-protein conjugate vaccines . Inactivated oral cholera vaccines consisting of inactivated Vibrio cholerae O1 bacteria alone or in combination with B subunit of cholera toxin conferred 50-53% protection in a field trial in Bangladesh . An engineered live oral cholera vaccine, strain CVD 103-HgR, has been shown in extensive clinical trials to be well tolerated and highly immunogenic after a single oral dose . In experimental challenge studies, a single dose of CVD 103-HgR conferred significant protection against challenge with wild-type V . cholerae O1 . Several candidate vaccines against Shigella and enterotoxigenic E . coli are in clinical trials . Finally, a multivalent rotavirus vaccine (rhesus reassortant) is undergoing extensive field testing .

P N G Med J, 1995 Dec, 38(4), 315 - 9
The role of the laboratory in the diagnosis and management of typhoid fever; Clegg A; In typhoid-endemic areas the results obtained from the laboratory are important in confirming the clinical diagnosis of typhoid and may also contribute to decisions made on the management and treatment of typhoid cases . Isolation of Salmonella typhi remains the gold standard, with culture from bone marrow aspirate or a combination of specimens from other body sites resulting in the greatest sensitivity . Antibody detection techniques may still provide valuable information, but only if the results are interpreted in the context of the background antibody levels in the local population . None of the available antigen detection techniques have been consistently demonstrated to be of diagnostic value and a recently developed polymerase chain reaction (PCR) for the detection of Salmonella typhi has yet to undergo a full-scale clinical evaluation . The initial identification of chronic typhoid carriers relies upon the detection of elevated Vi capsular antibody levels, but seeking out chronic carriers will be of limited value in controlling the spread of typhoid in areas where transmission is principally mediated by convalescent excretors . Whilst resistance of Salmonella typhi to antibiotics has emerged as an increasing problem in some areas of the world, it is still uncommon in isolates from Papua New Guinea . However, monitoring of antibiotic susceptibility patterns will ensure that signs of developing resistance are detected early and that the appropriate action is taken.

P N G Med J, 1995 Dec, 38(4), 300 - 4
The new problem of typhoid fever in Papua New Guinea: how do we deal with it?
Passey M.
This paper reviews some of the issues relating to typhoid fever in Papua New Guinea . Before the mid-1980s only sporadic cases of typhoid were reported but it is now one of the greatest public health problems in the highlands and some urban areas . In one study near Goroka an annual incidence rate of 1208 per 100,000 people was found, with settlers from other areas at greater risk than the local landowners . Problems relating to management included differentiation from other diseases, the limitations of the Widal test and poor compliance among outpatients . In Papua New Guinea it appears that transmission is largely from person to person, with little evidence for water-borne transmission . The prolonged convalescent excretion of Salmonella typhi and the difficulties this poses for control of the disease are discussed . Prevention will only be achieved in the long term by improvements in hygiene and sanitation, though more immediate control could be achieved by vaccination with an appropriate vaccinePIP: Few cases of typhoid fever were reported in Papua New Guinea (PNG) before 1960 and only sporadic cases were reported during the 1960s . However, typhoid fever has now become a major public health problem in the country, endemic throughout the Highlands Region and in some of the larger coastal towns such as Port Moresby . In 1993 and 1994, there were 4485 and 4551 people, respectively, reported to have been admitted with typhoid fever throughout PNG, with 87% and 73% of these cases, respectively, occurring in the Highlands Region . The vast majority of the remainder of patients were in the National Capital District, Central, or Morobe Provinces . No data are available on the number of outpatient cases . The transmission of typhoid fever in PNG appears to be mainly from person to person, with little evidence of water-borne transmission . Problems posed by the prolonged convalescent excretion of Salmonella typhi are discussed . Typhoid fever will be prevented over the long term by improvements in hygiene and sanitation, although more immediate control could be achieved through vaccination with an appropriate vaccine .

Arch Intern Med, 1998 Mar 23, 158(6), 633 - 8
Typhoid fever in the United States, 1985-1994: changing risks of international travel and increasing antimicrobial resistance; Mermin JH et al.; BACKGROUND: Typhoid fever is a potentially fatal illness common in the less industrialized world . In the United States, the majority of cases occur in travelers to other countries . METHODS: We reviewed surveillance forms submitted to the Centers for Disease Control and Prevention, Atlanta, Ga, for patients with culture-confirmed typhoid fever between 1985 and 1994 . RESULTS: The Centers for Disease Control and Prevention received report forms for 2445 cases of typhoid fever . Median age of patients was 24 years (range, 0-89 years) . Ten (0.4%) died . Seventy-two percent reported international travel within the 30 days before onset of illness . Six countries accounted for 80% of cases: Mexico (28%), India (25%), the Philippines (10%), Pakistan (8%), El Salvador (5%), and Haiti (4%) . The percentage of cases associated with visiting Mexico decreased from 46% in 1985 to 23% in 1994, while the percentage of cases associated with visiting the Indian subcontinent increased from 25% in 1985 to 37% in 1994 . The incidence of typhoid fever in US citizens traveling to the Indian subcontinent was at least 18 times higher than for any other geographic region . Complete data on antimicrobial susceptibility to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole were reported for 330 (13%) Salmonella Typhi isolates . Isolates from 1990 to 1994 were more likely than isolates from 1985 to 1989 to be resistant to any of these antimicrobial agents (30% vs 12%; P<.001) and to be resistant to all 3 agents (12% vs 0.6%; P<.001) . CONCLUSIONS: American travelers to less industrialized countries, especially those traveling to the Indian subcontinent, continue to be at risk for typhoid fever . Antimicrobial resistance has increased, and a quinolone or third-generation cephalosporin may be the best choice for empirical treatment of typhoid fever.

Adv Virus Res, 1998, 50, 141 - 82
Core particles of hepatitis B virus as carrier for foreign epitopes; Ulrich R et al.; To be effective as vaccines, most monomeric proteins and peptides either require chemical coupling to high molecular weight carriers or application together with adjuvants . More recently, recombinant DNA techniques have been used to insert foreign epitopes into proteins with inherent multimerization capacity, such as particle-forming viral capsid or envelope proteins . The core protein of hepatitis B virus (HBcAg), because of its unique structural and immunological properties, has gained widespread interest as a potential antigen carrier . Foreign sequences of up to approximately 40 amino acid residues at the N terminus, 50 or 100 amino acids in the central immunodominant c/e 1 epitope region of HBcAg, and up to 100 or even more residues at the C terminus, did not interfere with particle formation . The humoral immunogenicity of inserted epitopes is determined by the immunogenicity of the peptide itself and its surface exposure, and is influenced by the route of application . The probably flexible and surface-exposed c/e1 region emerged as the most promising insertion site . When applied together with adjuvants approved for human and veterinary use, or even without adjuvants, such chimeric particles induced B and T cell immune responses against the inserted epitopes . In some cases neutralizing antibodies, cytotoxic T cells and protection against challenge with the intact pathogen were demonstrated . Major factors for the potentiated immune response against the foreign epitopes are the multimeric structure of chimeric HBcAg that results in a high epitope density per particle, and the provision of T cell help by the carrier moiety . Beyond its use as subunit vaccine, chimeric HBcAg produced in attenuated Salmonella strains may be applicable as live vaccine.

Food Chem Toxicol, 1998 Feb, 36(2), 127 - 34
Lack of genotoxic effects of sucrose acetate isobutyrate (SAIB); Myhr BC et al.; Sucrose acetate isobutyrate (SAIB) was tested for potential genotoxic activity in four different in vitro assay systems . Two independent trials of a Salmonella reverse mutation assay (using strains TA98, TA100, TA1535, TA1537 and TA1538) showed no increases in revertant frequencies at doses up to 10,000 microg/plate which was non-toxic but exceeded the solubility limit . Similarly, no mutagenic response was observed at doses up to 1000 microg/ml at the HGPRT locus in cultured CHO cells; SAIB was toxic and its solubility limit was exceeded at 50 microg/ml . No clastogenic activity was detected in cultured CHO cells at concentrations up to 2000 microg/ml . All three preceding in vitro tests were conducted both in the presence and absence of Aroclor 1254-induced rat liver S-9 metabolic activation systems . An unscheduled DNA synthesis assay also was performed using rat primary hepatocyte cultures with doses up to 1000 microg/ml, and no DNA repair was detectable . Thus, SAIB was stringently tested at doses exceeding the solubility limit in culture medium and causing toxicity to CHO cells without obtaining any evidence for genotoxic activity as a mutagen, clastogen, or DNA-damaging agent.

Eur J Epidemiol, 1998 Jan, 14(1), 99 - 106
An outbreak of Salmonella hadar associated with food consumption at a building site canteen; Faustini A et al.; A biphasic outbreak of gastroenteritis caused by Salmonella hadar affected canteen employees and workers at a construction site in central Italy in September 1994 . There were 448 symptomatic cases, from 61 of whom group C Salmonella was isolated . Six cases were canteen employees . Twenty-two other individuals were asymptomatic excreters . There were 10 secondary cases . Working as a food handler at the canteen constituted an increased risk of infection, independently of ingestion of the food (odds ratio: 62.1; 95% confidence interval (CI): 9.5-406.6) . Having eaten at the canteen on the 19th and 20th September was identified as risk factor for subjects symptomatic within 72 hours (relative risk (RR): 17.0, 95% CI: 2.3-124.3), and cooled meat salad was identified as the vehicle of infection (RR: 36.6, 95% CI: 14.3-93.8) . The use of portable toilets was another possible route of transmission of infection for all cases (RR: 1.3, 95% CI: 1.0-1.6) . The index case was a cook who had symptoms five days before the peak of the outbreak . From 27 individuals both symptomatic and asymptomatic excreters group B, group D and not-typed Salmonellas were isolated . This study underlines the problem of improper food handling in salmonellosis outbreaks and emphasizes the role of several vehicles in the transmission of salmonellosis in a community.

J Biol Chem, 1998 Feb 13, 273(7), 3817 - 29
Identification of a novel core type in Salmonella lipopolysaccharide . Complete structural analysis of the core region of the lipopolysaccharide from Salmonella enterica sv . Arizonae O62; Olsthoorn MM et al.; For the first time, the complete structure of a lipopolysaccharide (LPS) core region from Salmonella enterica has been identified that is different from the Ra core type generally thought to be present in all Salmonella LPS . The LPSs from two rough mutants and the smooth form of S . enterica sv . Arizonae IIIa O62, which all failed to react with an Ra core type-specific monoclonal antibody and were resistant to phage FO1, were analyzed after chemical modification using monosaccharide analysis, mass spectrometry, and NMR spectroscopy . In the novel core type, the terminal D-GlcNAc residue present in the Ra core type, is replaced by a D-Glc residue . The O-specific polysaccharide is alpha1-->4-linked to the second distal Glc residue of the core . Furthermore, phosphoryl substituents attached to O-4 of L-glycero-D-manno-heptose (Hep) I and II were identified as 2-aminoethyl diphosphate (on Hep I) and phosphate (Hep II) . {structure: see text} Abbreviations in Structure I are as follows: Hepp, L-glycero-D-manno-heptopyranose; Kdo, 3-deoxy-D-manno-oct-2-ulopyranosonic acid; PPEA, 2-aminoethyl diphosphate; R, O-specific polysaccharide . The presence of this novel core type in LPS of S . enterica should be taken into account in the development of a general antibody-based diagnostic system for Salmonella.

Environ Health Perspect, 1996 Oct, 104S(5), 1095 - 100
Predictions for the Outcome of Rodent Carcinogenicity Bioassays: Identification of Trans-species Carcinogens and Noncarcinogens
Tennant RW, Spalding J.
Thirty chemicals or substances currently undergoing long-term carcinogenicity bioassays in rodents have been used in a project to further evaluate methods and information that may have the capability of predicting potential carcinogens . In our predictions the principal information used includes structural alerts and in vitro test results for Salmonella mutagenicity, relative subchronic toxicity, and the sites and types of pathology found in subchronic (90-day) studies . This group of chemicals differs significantly from those used previously to evaluate predictive methods in that 23 of 30 are defined as nonmutagenic by conventional criteria . The goal of this predictive effort is to identify categorically the chemicals that have the capacity to induce cancers in both rats and mice (trans-species carcinogens) and those that are not carcinogenic in either rats or mice . Chemicals that show properties that may be associated with tumor induction in either species, i.e., species-specific cancers, are categorized as being of "uncertain predictability." This category includes chemicals believed to have limited carcinogenic potential that is manifested principally as a consequence of the genetic background of the test strain of inbred rodent.

Environ Health Perspect, 1996 Oct, 104S(5), 1065 - 73
Prediction of Rodent Carcinogenicity Using the DEREK System for 30 Chemicals Currently Being Tested by the National Toxicology Program
Marchant CA.
DEREK is a knowledge-based expert system for the qualitative prediction of toxicity . The DEREK system has been used to predict the carcinogenicity in rodents of the 30 chemicals in the second National Toxicology Program (NTP) carcinogenicity prediction exercise . Seven of the chemicals were predicted to be carcinogens . For 23 chemicals, there was no evidence in the DEREK knowledge base to suggest carcinogenic activity . Supplementary data from a variety of sources have been evaluated by human experts to assess confidence in each DEREK prediction . These sources included standard toxicology reference texts, genotoxicity and subchronic toxicity assay results for each chemical, as well as Salmonella mutagenicity and carcinogenicity data for close structural analogues . This process has led to the proposal of a number of improvements to the DEREK carcinogenicity knowledge base.

Environ Health Perspect, 1996 Oct, 104S(5), 1011 - 6
COMPACT and Molecular Structure in Toxicity Assessment: A Prospective Evaluation of 30 Chemicals Currently Being Tested for Rodent Carcinogenicity by the NCI/NTP
Lewis DFV, Ioannides C, Parke DV.
A new series of 30 miscellaneous National Toxicology Program chemicals has been evaluated prospectively for carcinogenicity and overt toxicity by COMPACT (Computer Optimised Molecular Parametric Analysis for Chemical Toxicity: CYP1A and CYP2E1) . Evaluations were also made by Hazardexpert, and for metal ion redox potentials; and these, together with COMPACT, were compared with results from the Ames test for mutagenicity in Salmonella, the micronucleus test, and 90-day subchronic rodent pathology . Seven of the 30 chemicals (nitromethane, chloroprene, xylenesulfonic acid, furfuryl alchohol, anthraquinone, emodin, cinnamaldehyde) were positive for potential carcinogenicity in the COMPACT evaluation; xylenesulphonic acid and furfuryl alchohol were only equivocally positive . Four of the 30 chemicals--scopolamine, D&C Yellow No . 11, citral, cinnamaldehyde--were positive by Hazardexpert; 6 of 30--D&C Yellow No . 11, 1-chloro-2-propanol, anthraquinone, emodin, sodium nitrite, cinnamaldehyde--were positive in the Ames test; 2 of 30--phenolphthalein and emodin--were positive in the in vivo cytogenetics test; and 3 of 30--molybdenum trioxide, gallium arsenide, vanadium pentoxide--were metal compounds with redox potentials of the metal/metal ion indicative of possible carcinogenicity . The overall prediction for carcinogenicity was positive for 12 of 30 chemicals: nitromethane, chloroprene, D&C Yellow No . 11, molybdenum trioxide, 1-chloro-2-propanol, furfuryl alcohol, gallium arsenide, anthraquinone, emodin, sodium nitrite, cinnamaldehyde, vanadium pentoxide) . This overall prediction has been made on the basis of the results of the computer tests and from consideration of the information from bacterial mutagenicity, together with likely lipid solubility and pathways of metabolism and elimination

Environ Health Perspect, 1996 Oct, 104S(5), 1031 - 40
Prediction of Rodent Carcinogenicity Bioassays from Molecular Structure Using Inductive Logic Programming
King RD, Srinivasan A.
The machine learning program Progol was applied to the problem of forming the structure-activity relationship (SAR) for a set of compounds tested for carcinogenicity in rodent bioassays by the U.S . National Toxicology Program (NTP) . Progol is the first inductive logic programming (ILP) algorithm to use a fully relational method for describing chemical structure in SARs, based on using atoms and their bond connectivities . Progol is well suited to forming SARs for carcinogenicity as it is designed to produce easily understandable rules (structural alerts) for sets of noncongeneric compounds . The Progol SAR method was tested by prediction of a set of compounds that have been widely predicted by other SAR methods (the compounds used in the NTP's first round of carcinogenesis predictions) . For these compounds no method (human or machine) was significantly more accurate than Progol . Progol was the most accurate method that did not use data from biological tests on rodents (however, the difference in accuracy is not significant) . The Progol predictions were based solely on chemical structure and the results of tests for Salmonella mutagenicity . Using the full NTP database, the prediction accuracy of Progol was estimated to be 63% (+/- 3%) using 5-fold cross validation . A set of structural alerts for carcinogenesis was automatically generated and the chemical rationale for them investigated--these structural alerts are statistically independent of the Salmonella mutagenicity . Carcinogenicity is predicted for the compounds used in the NTP's second round of carcinogenesis predictions . The results for prediction of carcinogenesis, taken together with the previous successful applications of predicting mutagenicity in nitroaromatic compounds, and inhibition of angiogenesis by suramin analogues, show that Progol has a role to play in understanding the SARs of cancer-related compounds.

Gene, 1998 Jan 30, 207(2), 149 - 57
Improved allelic exchange vectors and their use to analyze 987P fimbria gene expression; Edwards RA et al.; A series of vectors has been developed to provide improved positive and negative selection for allelic exchange . Based on homologous regions of DNA ranging in size from less than 200 bp to over 1 kb, we have successfully used these new plasmids to introduce or remove markers in chromosomal or plasmid DNA . Wild type fimbria genes were replaced both in Salmonella enteritidis (sefA, agfA and fimC) and Escherichia coli (fasA and fasH) . Regulation of 987P fimbriation could be identified after replacement of fasA and fasH with allelic reporter fusions . The expression of fasA but not fasH is dependent upon the osmolarity of the growth medium in an HNS-dependent manner, but unlike some other fimbrial systems expression is not dependent on the exogenous iron concentration.

Br Poult Sci, 1997 Dec, 38(5), 485 - 8
Evaluation of the influence of supplementing the diet with mannose or palm kernel meal on Salmonella colonisation in poultry; Allen VM et al.; 1 . The dietary inclusion of 15 and 25 g/kg mannose was associated with a reduction in the numbers of Salmonella enteritidis (PT4) in the caecal contents of chicks challenged by the food . The same benefit was not recorded for S . infantis, possibly because this strain, unlike S . enteritidis PT4, lacked mannose-sensitive fimbriae . 2 . The addition of 25 g/kg palm kernel meal (PKM), but not 20 g/kg desiccated coconut, to the food reduced the degree of salmonella colonisation in the intestinal tract of broiler chicks given diets contaminated with S . kedougou or S . enteritidis from the day of their arrival from the hatchery . 3 . The beneficial effect of PKM was also demonstrated at an inclusion rate of 5 g/kg and was similar for preparations with a particle size of either < 150 microns or < 300 microns . 4 . Day-old birds challenged orally with S . enteritidis and given food supplemented with 25 g/kg PKM, became clear of infection by 3 weeks of age while birds given unsupplemented food remained infected . 5 . These preliminary results suggest that the inclusion of PKM, which contains inter alia, oligosaccharides containing mannose, in the diet of chicks may reduce the extent to which the intestine is contaminated with salmonellas.

Annu Rev Med, 1998, 49, 275 - 87
Infection genomics: Nramp1 as a major determinant of natural resistance to intracellular infections; Skamene E et al.; The scope of the tuberculosis (TB) epidemic in the world today is enormous, with about 30 million active cases . Current research into preventing the spread of TB is focused on development of new drugs to inactivate Mycobacterium tuberculosis, the causative agent of TB, as well as on identifying the critical steps of host defense to infection with Mycobacteria, which might also yield therapeutic targets . Our infection genomics approach toward the latter strategy has been to isolate and characterize a mouse gene, Bcg (Nramp1), which controls natural susceptibility to infection with Mycobacteria, as well as Salmonella and Leishmania . Through comparative genomics, we have identified the homologous human NRAMP1 gene, alleles of which are now being used for tests of linkage with TB and leprosy.

Bioessays, 1998 Jan, 20(1), 96 - 101
The ins and outs of virulence gene expression: Mg2+ as a regulatory signal; Groisman EA; The facultative intracellular pathogen Salmonella enterica serovar Typhimurium faces multiple environments during infection, including different cell types as well as extracellular fluids . We propose that Salmonella ascertains its cellular location by assessing the Mg2+ concentration of its milieu . A signal transduction system, PhoP/PhoQ, signals Salmonella its presence in a intracellular (low Mg2+) or extracellular (high Mg2+) environment, thereby promoting transcription of genes required for survival within or entry into host cells . The PhoP/PhoQ system is high in a regulatory hierarchy that controls other signal transduction systems that respond to different host cues, enabling the microorganism to determine its precise tissue and cellular location.

J Clin Microbiol, 1998 Mar, 36(3), 674 - 8
Discrimination of strains of Salmonella enteritidis with differing levels of virulence by an in vitro glass adherence test; Solano C et al.; The objective of this study was the in vitro differentiation of isolates of Salmonella enteritidis whose virulences differed in a chick model . A total of 14 strains of S . enteritidis were isolated from either the environment, dairy products, or infected patients . The isolates could be divided into two groups on the basis of their virulence (50% lethal dose) in chickens infected intraperitoneally . When the strains were incubated in adherence test medium (Spanish patent 9700408), only the virulent strains produced aggregates and formed visible filaments attached to the glass tube . These results suggest, although for a limited number of strains, that aggregation in such a medium could be used as a diagnostic tool to discriminate virulent strains of S . enteritidis.

Vet Rec, 1998 Feb 7, 142(6), 138 - 9
Abortion in foxhounds and a ewe flock associated with Salmonella montevideo infection; Caldow GL et al.; Salmonella montevideo is a recognised cause of ovine abortion and can cause disease in other domestic animals and humans . The organism was isolated from the aborted fetuses of a bitch from a pack of foxhounds . The subsequent collection of rectal swabs from the foxhounds at approximately two week intervals over a 48-day period resulted in the isolation of S montevideo from 50 of the 61 hounds in the pack on one or more occasions . Some of the hounds had gained access to an open pit containing dead ewes and aborted fetuses on a farm where the housed ewe flock was experiencing S montevideo infection . The S montevideo isolates from both the ovine and canine samples had a plasmid of 120 kilobases with an identical restriction endonuclease fragmentation pattern . The only other isolate from a contemporary outbreak lacked this plasmid . It was concluded that this case offered further evidence of the potential for salmonella infection to be spread by the scavenging of carcasses.

Int J Parasitol, 1998 Jan, 28(1), 21 - 8
Genetics of host resistance and susceptibility to intramacrophage pathogens: a study of multicase families of tuberculosis, leprosy and leishmaniasis in north-eastern Brazil; Blackwell JM; Genetic analysis of disease phenotypes segregating in recombinant inbred, congenic and recombinant haplotype mouse strains permitted us to effectively "scan" the murine genome for genes controlling resistance and susceptibility to leishmanial infections . Five major regions were implicated which, because they show conserved synteny with regions of the human genome, immediately provide candidate gene regions for human disease susceptibility genes . A common intramacrophage niche for leishmanial and mycobacterial pathogens, and a similar spectrum of immune response and disease phenotypes, also led to the prediction that the same genes/candidate gene regions might be responsible for genetic susceptibility to mycobacterial infections such as leprosy and tuberculosis . Indeed, one of the murine genes (Nramp1) was identified for its role in controlling a range of intramacrophage pathogens, including leishmanial, salmonella and mycobacterial infections . In recent studies, multicase families of visceral leishmaniasis, tuberculosis and leprosy, from north-eastern Brazil have been analysed to determine the role of these candidate genes/regions in humans . Complex segregation analysis provides evidence for one or two major genes controlling susceptibility to these diseases in this population . Family-based linkage analyses (e.g., combined segregation and linkage analysis; sib-pair analyses) and transmission disequilibrium testing have been used to examine the role of four regions in disease susceptibility and/or immune response phenotypes . Results to date demonstrate: (1) the major histocompatibility complex (MHC:H-2 in mouse, HLA in humans: mouse chromosome 17/human 6p; candidates class II and class III including tumour necrosis factor alpha/beta genes) shows both linkage to, and allelic association with, leprosy per se, but is only weakly associated with visceral leishmaniasis and shows neither linkage to, nor allelic association with, tuberculosis; (2) no evidence for linkage between NRAMP1, the positionally cloned candidate for the murine macrophage resistance gene Ity/Lsh/Bcg (mouse chromosome 1/human 2q35), and susceptibility to tuberculosis or visceral leishmaniasis; (3) the region of human chromosome 17q (candidates NOS2A, SCYA2-5) homologous with distal mouse chromosome 11 is linked to tuberculosis susceptibility; and (4) the "T helper 2" cytokine gene cluster (proximal murine chromosome 11/human 5p; candidates IL4, IL5, IL9, IRF1, CD14) is not linked to human disease susceptibility for any of the three infections, but shows linkage to and highly significant allelic association with ability to mount an immune response to mycobacterial antigens . The demonstration of an allelic association between IL4 and immune response to mycobacterial antigen may provide a genetic explanation for the inverse association recently demonstrated between delayed hypersensitivity T helper 1 responses to mycobacterial antigen and atopic disorder in Japanese children . These studies demonstrate that the "mouse-to-human" strategy, refined by our knowledge of the human immune response to infection, can lead to the identification of important candidate gene regions in humans.

FEMS Microbiol Lett, 1998 Feb 15, 159(2), 255 - 60
The presence of genes homologous to the K88 genes faeH and faeI on the virulence plasmid of Salmonella gallinarum; Rychlik I et al.; A Tn3 insertion mutation was produced in the virulence plasmid of a strain of Salmonella gallinarum which conferred avirulence by parenteral and oral routes but which was also less invasive following oral inoculation . The transposon was found to have inserted near an open reading frame (ORF) with no homologies in the data banks . This ORF was adjacent to two additional ORF's with a high degree of homology of Escherichia coli genes encoding the minor structural subunits (FaeH and FaeI) of the K88 fimbria . A similar region of homology was found by DNA-DNA hybridization on the virulence plasmids of S . pullorum, S . dublin and other S . gallinarum strains but not in the plasmids of S . typhimurium, S . enteritidis or S . choleraesuis.

Cytobios, 1997, 90(362-363), 193 - 201
Polarizing response of human polymorphonuclear cells to Vibrio cholerae; Valenza MA et al.; Leucocytes have the capacity to respond to chemotactic factors by becoming morphologically and functionally polarized and this method has been found to be suitable for measurement of chemotaxis . This work evaluates the effect of whole Vibrio cholerae biotype El Tor polarization of human polymorphonuclear (PMN) cells in comparison with strains of V . cholerae NAG, Vibrio alginolyticus and Salmonella typhi . V . cholerae O1 induced, at different cell/bacteria ratios, a significant increase in the percentage of polarized cells compared with PMN cells stimulated with formylmethionyl-leucyl-phenylalanine (FMLP) and the other bacteria tested . The capacity of V . cholerae O1 to induce PMN cell polarization may play a role on the inflammatory response recently described in diarrhoea caused by V . cholerae.

Intensive Care Med, 1998 Jan, 24(1), 48 - 54
Comparison of the haemodynamic effects of nitric oxide synthase inhibition and nitric oxide scavenging in endotoxaemic sheep; Bone HG et al.; OBJECTIVE: The present study compared the effects of nitric oxide (NO) synthase inhibition and NO scavenging with haemoglobin in endotoxaemic sheep . DESIGN: 12 sheep were instrumented for chronic study . Six sheep received LG-nitro-arginine-methylester (L-NAME, 2.5 mg/kg bolus followed by a continuous infusion of 0.5 mg/kg per h), the other 6 sheep received pyridoxalated haemoglobin polyoxyethylene conjugate (PHP, 100 mg/kg bolus followed by a continuous infusion of 20 mg/kg per h) . MEASUREMENTS AND RESULTS: Haemodynamic and oxygenation parameters were measured in healthy sheep, after infusion of Salmonella typhosa endotoxin (10 ng/kg per min) for 24 h and after infusion of L-NAME or PHP . The infusion of endotoxin resulted in a hypotensive, hyperdynamic circulation . Infusion of L-NAME increased mean arterial pressure (MAP) from 76.1 +/- 4.2 mmHg to normal values of 95.8 +/- 5.7 mmHg (p < 0.05) . PHP increased MAP from 73.0 +/- 3.0 to 88.6 +/- 4.7 mmHg (p < 0.05) . This increase in MAP was associated in the L-NAME group with a more prominent drop in cardiac index (from 10.2 +/- 0.4 to 7.0 +/- 0.51.min-1.m-2; p < 0.05) than in the PHP group (from 10.7 +/- 0.2 to 9.3 +/- 0.61.min-1.m-2) . During the first 90 min of infusion, cardiac index remained lower in the L-NAME group than in the PHP group . The increase in pulmonary vascular resistance was also higher in the L-NAME group . CONCLUSION: These results suggest, that at the doses used in the experiment, NO scavenging with PHP has smaller effects on cardiac index and pulmonary vascular resistance than NO synthase inhibition with L-NAME . Therefore, the concept of NO scavenging in hyperdynamic sepsis should be further evaluated.

Clin Infect Dis, 1998 Feb, 26(2), 290 - 6
Fatal Mycobacterium tuberculosis bloodstream infections in febrile hospitalized adults in Dar es Salaam, Tanzania; Archibald LK et al.; Causes of community-acquired bloodstream infections (BSIs) in sub-Saharan Africa are unknown with regard to mycobacteria and fungi . We prospectively studied 517 consecutive febrile (axillary temperature, > or =37.5 degrees C) adults (> or =15 years of age) admitted to one hospital in Tanzania . After hospital admission and informed consent, blood was drawn for culture (of bacteria, mycobacteria, and fungi), determination of human immunodeficiency virus type 1 (HIV-1) status, and malaria smears . Malaria smears were prepared for a control group of 150 afebrile patients . One hundred and forty-five patients (28%) had BSI . Of these 145 patients, 118 (81%) were HIV-1-infected . HIV-positive patients were more likely than HIV-negative ones to have BSI (118 of 282 vs . 27 of 235; P < .0001) . The three most frequently isolated pathogens were Mycobacterium tuberculosis (60 {39%}), non-typhi Salmonella species (29 {19%}), and Staphylococcus aureus (13 {8.3%}) . The incidence of malaria parasitemia was similar in study and control patients (9.5% vs . 8%) . In this patient population with high prevalence of HIV-1 infection, M . tuberculosis has become the foremost cause of documented BSI.

Appl Environ Microbiol, 1998 Mar, 64(3), 999 - 1005
Thermal tolerance of Mycobacterium paratuberculosis; Sung N et al.; D values (decimal reduction time; the time required to kill 1 log concentration of bacteria) were determined for both human and bovine strains (Dominic, Ben, BO45, and ATCC 19698) of Mycobacterium paratuberculosis in 50 mM lactate solution (pH 6.8) and in milk at four temperatures (62, 65, 68, and 71 degrees C) . Viable M . paratuberculosis organisms were quantified by a radiometric culture method (BACTEC) . Thermal death curves for the M . paratuberculosis strains tested were generally linear, with R2 of > or = 0.90, but a few curves (R2, 0.80 to 0.90) were better described by a quadratic equation . The human strains (Dominic and Ben) had similar D values in milk and in lactate solution . However, D values for the bovine strains (BO45 and ATCC 19698) were significantly different depending on the menstruum . D values for low-passage clinical strains (Dominic, Ben, and BO45) were lower than those of the high-passage laboratory strain (ATCC 19698) . The D value based on pooled data for clinical strains of M . paratuberculosis in milk at 71 degrees C (D71 degrees C) was 11.67 s . Pooled D62 degrees C, D65 degrees C, and D68 degrees C of clinical M . paratuberculosis strains in milk were 228.8, 47.8, and 21.8 s, respectively . The Z value (the temperature required for the decimal reduction time to traverse 1 log cycle) of clinical strains in milk was 7.11 degrees C . The D values of clumped and single M . paratuberculosis cells were not significantly different . The D values of all M . paratuberculosis strains tested were considerably higher than those published for Listeria, Salmonella, and Coxiella spp . and estimated for Mycobacterium bovis, indicating that M . paratuberculosis is more thermally tolerant . This study supports the premise that M . paratuberculosis may survive high-temperature, short-time pasteurization when the initial organism concentration is greater than 10(1) cells/ml.

Rev Sci Tech, 1997 Aug, 16(2), 554 - 63
{The dangers for public health connected to the consumption of horse meat}; Magras C et al.; After an outline of the ways in which horse meat is produced and consumed, the authors review specific and general risks associated with this product, and methods for the control and prevention of these risks are given . With regard to biological hazards transmitted by horse meat, the relevant zoonoses are considered, followed by a discussion of the two principal agents responsible for foodborne disease in human beings: Salmonella and Trichinella . Among chemical hazards, the toxic effects of cadmium are prominent . Although these hazards can be identified, the actual risks to human health are difficult to estimate, because of the paucity of scientific data.

Rev Sci Tech, 1997 Aug, 16(2), 542 - 53
Epidemiology and control of egg-associated Salmonella enteritidis in the United States of America; Hogue A et al.; The isolation rate for Salmonella enterica serotype Enteritidis (SE) in humans in the United States of America (USA) increased from 1,207 sporadic isolates identified in 1976 (0.6 isolates/100,000 population) to 10,201 identified in 1995 (4.0/100,000 population) . The proportion of reported Salmonella isolates which were SE increased from 5% to 25% during the same time period . In 1990, 1994, and 1995, SE was the most commonly reported reported Salmonella serotype in the USA . Much of this increase has been associated with the consumption of contaminated shell eggs . An examination of the results of a United States Department of Agriculture (USDA) survey of spent hens at slaughter and unpasteurised liquid egg at breaker plants (liquid egg processors) in 1991 and 1995 reveals an increase in the prevalence of SE isolates overall and in most regions of the USA . SE phage type 4 (pt 4), the predominant SE phage type in other parts of the world, has emerged in the egg industry in the western USA concurrent with a sharp increase in the number of sporadic human SE pt 4 isolates in California and Utah . Research on the molecular structure and virulence of SE pt 4 isolates from the USA as compared with isolates from other parts of the world (human and poultry) should be a priority . A comparison of DNA from pt 4 isolates from the USA and Europe may provide information about the potential threat to public health and poultry in the USA from this phage type . Some regional success in the reduction of human illness as a result of SE control efforts is apparent . The Pennsylvania Egg Quality Assurance Program has shown progress in reducing SE infection in participating flocks . At a national level, however, neither the incidence of human illness due to SE nor the prevalence of SE in flocks and unpasteurised liquid eggs have decreased significantly, despite the implementation of the USDA 'trace back' regulation from 1990 to 1995, and intensified efforts to educate food handlers and to enforce safe food handling practices . More effort is needed to control SE at every stage of the egg continuum, from production through to consumption . A risk-reduction approach, with barriers to the introduction and multiplication of the pathogen throughout the farm-to-table continuum, is the most practical method for reducing human illness from SE in shell eggs at present . An effective long-term solution will require interdisciplinary efforts involving government, industry, consumers, and academics . Interventions should be developed and evaluated in compliance with the potential for reducing the risk to human health and cost-effectiveness.

Rev Sci Tech, 1997 Aug, 16(2), 359 - 68
The risks and prevention of contamination of beef feedlot cattle: the perspective of the United States of America; Smith RA et al.; There are currently no scientifically defined critical management points or critical control points to manage foodborne pathogens at the pre-harvest level . Research is ongoing: much of the pre-harvest research is funded by producer organisations . The beef industry has Beef Quality Assurance (BQA) programmes in place and these are dynamic . Groups of cattlemen have made a very strong commitment to reducing foodborne pathogens in beef . Fewer Escherichia coli O157:H7 organisms are shed by feedlot cattle near the end of the feeding period than by newly arrived cattle . Moreover, there is less shedding of the organisms in cattle of slaughter age than in younger cattle . The prevalence of E . coli O157:H7 in feedlot cattle is similar to that in range cattle . This suggests that concentrating cattle in feedlot dirt pens does not increase the risk of shedding E . coli organisms . Pen maintenance, considered a good management practice, appears to be an adequate means of keeping pathogen levels in pens low . It is not likely that pre-harvest food safety programmes will eliminate the threat of pathogens such as E . coli O157:H7 or Salmonella . The management of foodborne pathogens will become part of an integrated programme to enhance food safety which includes the producer, the packer, the distributors, retailers and the consumer . The feedlot industry initiated a residue avoidance programme several years ago . As a result, the risk of chemical residues in beef from feedlots in the United States of America is near zero . Hazard analysis and critical control point-type prevention programmes, using scientifically based critical management points, will help ensure that the risk remains negligible.

Nat Med, 1998 Mar, 4(3), 298 - 302
Activation of the contact-phase system on bacterial surfaces--a clue to serious complications in infectious diseases; Herwald H et al.; Fever, hypotension and bleeding disorders are common symptoms of sepsis and septic shock . The activation of the contact-phase system is thought to contribute to the development of these severe disease states by triggering proinflammatory and procoagulatory cascades; however, the underlying molecular mechanisms are obscure . Here we report that the components of the contact-phase system are assembled on the surface of Escherichia coli and Salmonella through their specific interactions with fibrous bacterial surface proteins, curli and fimbriae . As a consequence, the proinflammatory pathway is activated through the release of bradykinin, a potent inducer of fever, pain and hypotension . Absorption of contact-phase proteins and fibrinogen by bacterial surface proteins depletes relevant coagulation factors and causes a hypocoagulatory state . Thus, the complex interplay of microbe surface proteins and host contact-phase factors may contribute to the symptoms of sepsis and septic shock.

J Leukoc Biol, 1998 Mar, 63(3), 288 - 96
Increased P-selectin gene expression in the liver vasculature and its role in the pathophysiology of neutrophil-induced liver injury in murine endotoxin shock; Essani NA et al.; We studied the role of P-selectin, an adhesion molecule known to be important for neutrophil localization to sites of inflammation, in a model of inflammatory liver injury . Male C3Heb/FeJ (ET-sensitive) mice treated with 700 mg/kg galactosamine and 100 microg/kg Salmonella abortus equi endotoxin (Gal/ET), murine tumor necrosis factor alpha (TNF-alpha, 15 microg/kg), or interleukin-1 (IL-1, 13-23 microg/kg), showed increased P-selectin mRNA levels in the liver . In contrast, C3H/HeJ (ET-resistant) mice responded only to cytokines with P-selectin mRNA formation . Whereas no P-selectin expression was detectable in control livers, there was temporary staining of endothelium in large blood vessels but not in sinusoids between 3 and 5 h after ET, TNF-alpha, or IL-1 treatment . Severe liver injury induced by Gal/ET at 7 h was not inhibited by an anti-P-selectin antibody in C3Heb/FeJ mice or in P-selectin-deficient animals . Sequestration of neutrophils in sinusoids, i.e . those neutrophils that have been identified as critical for the injury, was not affected by the antibody or in P-selectin-deficient mice . However, the temporary margination in portal and post-sinusoidal venules was reduced by 75% in anti-P-selectin antibody-treated animals and by 51% in P-selectin-deficient mice . We conclude that hepatic P-selectin gene transcription in vivo involves cytokines . However, blocking P-selectin neither attenuated sinusoidal neutrophil sequestration nor prevented neutrophil-induced liver injury during endotoxin shock but attenuated neutrophil margination in larger vessels . Thus, our data demonstrate similarities and fundamental differences in the requirement for adhesion molecules to localize neutrophils in the liver vasculature compared to other organs during an inflammatory response.

Mutat Res, 1997 Dec, 385(3), 173 - 93
Carcinogens stimulate intrachromosomal homologous recombination at an endogenous locus in human diploid fibroblasts; Li J et al.; Mitotic recombination is believed to play an important role in the development of many cancers . An improved system has been developed to detect reversion of an intragenic DNA duplication, as a model for intrachromosomal homologous recombination . The 'LNtd' strain of human fibroblasts, derived from a Lesch-Nyhan donor, produces no detectable hypoxanthine phosphoribosyltransferase (HPRT) activity due to a 13.7-kilobase-pair DNA insertion duplicating exons 2 and 3 of the HPRT locus . These cells are therefore sensitive to selection in HAT medium, against cells lacking functional HPRT enzyme . Clonal reversion to HAT resistance occurs spontaneously at 1-3 x 10(-5)/cell/generation, and can be induced by brief exposure to a variety of carcinogenic agents . Six known carcinogens, including two (diethylstilbestrol and nickel chloride) which were non-mutagenic in Salmonella by Ames HIS-reversion tests, showed dose-dependent induction of LNtd reversion by a maximum of 2.4- to > 11-fold over controls (each p < 0.01) . In contrast, 5 non-carcinogenic agents, including two 'Ames-positive' chemicals, sodium azide and 8-hydroxyquinoline, evoked no more than a 1.7-fold increase in reversion (not significant) . The molecular events associated with reversion to HAT-resistance were characterized, relative to the parental strain, in HATR clones derived from either untreated or carcinogen-treated cells . Both the intron-3:intron-1 junction situated between the duplicated HPRT segments in LNtd cells (amplified by polymerase chain reaction), and a restriction fragment corresponding to the duplicated HPRT DNA (assessed by Southern-blot hybridization), were lost from the majority of HATR revertant clones, whether they arose spontaneously or following exposure to Cr(VI) or ultraviolet light . These results imply that HATR reversion is induced in LNtd cells by carcinogenic treatments, through a mechanism consistent with homologous recombination, and is highly concordant with induction of in vivo carcinogenesis by the same agents.

Int J Food Microbiol, 1997 Sep 16, 38(2-3), 211 - 6
Evaluation of a new enrichment broth for the isolation of Salmonella spp . from poultry products; Blivet D et al.; Four selective enrichment broths were compared for the detection of Salmonella spp . in naturally contaminated poultry products and the recovery of atypical Salmonella strains in suspensions of pure cultures . In analysis of 100 poultry samples, the sensitivities observed were 94.0% for Muller-Kauffmann Tetrathionate-Brilliant Green (MKTBG), 97.6% for Rappaport Vassiliadis (RV), 42.2% for Selenite Cystine (SC) and 97.6% for the new broth KIMAN (Whitley Impedance Broth supplemented with 20 mg/l of novobiocin sodium salt, 10 mg/l of malachite green oxalate and 40 g/l of potassium iodide) . The two most efficient broths--RV and KIMAN for recovery of atypical Salmonella strains (gallinarum biotypes gallinarum and pullorum, typhi, paratyphi A) were less toxic than MKTBG but more toxic than s.c . broth . According to these results, the use of RV and KIMAN could be a good combination to assure maximal recovery of Salmonella strains.

Int J Food Microbiol, 1997 Sep 16, 38(2-3), 95 - 102
A survey of Salmonella enteritidis in spent hens and its relation to farming style in Hokkaido, Japan; Sunagawa H et al.; In order to estimate the distribution of Salmonella including Salmonella enteritidis (SE) and SE-antibodies in commercial layer hen flocks in Hokkaido, the northern prefecture of Japan, a survey of spent layer hens was performed, from August 1996 to January 1997 . From the three spent hen processing plants, samples of intestines and sera were collected from 740 birds presented for slaughter from 37 flocks of 22 layer hen farms . Intestines from each birds were cultured for Salmonella including Salmonella enteritidis . Serum from each bird was examined for SE-antibody with the enzyme-linked immunosorbent assay (ELISA) . Salmonella (any serotype) and Salmonella enteritidis were isolated from 50 (6.8%) and three (0.4%) of 740 birds, respectively, and SE-antibody positive values were recorded from seven birds (0.9%) . SE-antibody positive birds did not always indicate isolation of Salmonella enteritidis, however SE-antibody positive hens were demonstrated only from Salmonella enteritidis positive flocks . Salmonellae were isolated from the birds of ten layer hen farms, all of these hens were raised in houses without windows and with automatic feeders . No isolations of salmonella were made from birds raised in houses with windows . From the windowless houses, Salmonellae were isolated from 46 (21.8%) of 260 birds in houses with four to six cages piled up vertically, and from six (2.5%) of 240 samples from the houses with four to five cages piled in a slanting manner.

Int J Food Microbiol, 1997 Aug 19, 38(1), 31 - 44
Development of thermal inactivation models for Salmonella enteritidis and Escherichia coli O157:H7 with temperature, pH and NaCl as controlling factors; Blackburn CW et al.; The thermal inactivation of Salmonella enteritidis phage type 4 and Escherichia coli O157:H7 as affected by temperature (54.5-64.5 degrees C), pH (4.2-9.6 with HCl or NaOH) and NaCl concentration (0.5-8.5% w/w) was studied . Cell suspensions in modified tryptone soya broth were heated in a submerged-coil heating apparatus and survivors were enumerated on tryptone soya agar incubated aerobically . For most thermal inactivation data there was a logarithmic decrease in the viable cell concentration over the initial 4-6 log10 reduction and D-values were fitted . In some cases, tailing of the survivor curves was observed with cells surviving longer than the D-values predicted . Models describing the effect of temperature, pH and NaCl concentration on the thermal inactivation of S . enteritidis and E . coli O157:H7 were produced . For both organisms, predicted z-values of 4.6-7.0 C degrees were obtained depending on conditions, with larger z-values at higher levels of NaCl . Optimum survival occurred between pH 5 and pH 7 and increasing acidity or alkalinity caused a decrease in the predicted D-values . At equivalent pH, acetic acid and lactic acid (at 0.5, 1 and 2% w/w) generally had a similar, or increased, lethal effect compared with HCl, whereas in most cases citric acid had a less lethal effect . For E . coli O157:H7, increasing NaCl concentration had a protective effect up to the maximum tested (8.5% w/w), while for S . enteritidis optimal survival at a NaCl concentration of 5-7% w/w was predicted . The models were validated in foods by comparing predictions with published data . Most (80%) of the predicted D-values from the S . enteritidis model were within the 95% confidence interval (within 2.45-fold of the published data) for different Salmonella serotypes in whole egg, egg albumen, egg yolk, beef and milk . Most (93%) of the predicted D-values from the E . coli O157:H7 model were larger than the limited published data for this organism in meat, poultry, milk and apple juice with 42% within the 95% confidence interval (within 2.05-fold of the published data) . The D-value models were incorporated into Version 1, and subsequent versions, of the predictive microbiology software program, Food MicroModel.

New Microbiol, 1998 Jan, 21(1), 9 - 14
Comparative effect of gentamicin and pefloxacin treatment on the late stages of mouse typhoid; Bonina L et al.; The present study compares the ability of gentamicin and pefloxacin to eradicate a Salmonella infection in BALB/c mice when the treatment is instituted in the late stages of the infection . The results indicate that pefloxacin is highly effective in the treatment of mouse typhoid even when the therapy is instituted after the suppression of bacterial growth in the reticuloendothelial system (RES) . Conversely, gentamicin treatment only reduced the bacterial load in the RES of infected mice, but neither induced the clearance of the organisms from the RES, nor prevented the resurgence of bacterial growth . Even when using gentamicin at a high dosage, bacterial clearance could not be accomplished.

Eur J Cancer Prev, 1997 Dec, 6(6), 557 - 9
Chronic typhoid carriage and carcinoma of the gallbladder; Nath G et al.; Chronic microbial infections and/or their carrier state have been reported to be associated with particular cancers . Since typhoid infections and carcinoma of the gallbladder (the site where salmonella usually persists) are endemic in northern India, it was considered important to explore the relationship between the two . In the present study, a total of 1001 bile specimens collected from cases of carcinoma of the gallbladder (28), cholelithiasis (56) and individuals without biliary pathology (17) were subjected to aerobic cultures that had been enriched for salmonella . Salmonella typhi and S . paratyphi-A could be detected in a significantly higher (P < 0.05) number in patients with carcinoma of the gallbladder as compared with cholelithiasis and control groups . The existence of such an association indicates that detection and eradication of typhoid carriers may lead to a decrease in the incidence of carcinoma of the gallbladder along with typhoid fever.

Poult Sci, 1998 Feb, 77(2), 271 - 5
Effect of genetics, vaccine dosage, and postvaccination sampling interval on early antibody response to Salmonella enteritidis vaccine in broiler breeder chicks; Kaiser MG et al.; Broiler breeder chicks of two different genetic lines were evaluated for early antibody response to Salmonella enteritidis (SE) vaccine . Antibody responses to three dosages of SE vaccine administered at 22 d of age were measured at 3, 6, and 10 d postvaccination . Within each line, antibody levels at 10 d postvaccination were significantly higher than at either 3 or 6 d postvaccination . At all vaccine dosages, there was a significant antibody-response difference between the genetic lines at 6 and 10 d postvaccination . The vaccine dosage significantly affected antibody levels in one of the two genetic lines . These results demonstrate a genetic component of early antibody response to SE vaccine in broiler breeder chicks.

FEMS Microbiol Lett, 1998 Mar 1, 160(1), 37 - 41
Characterisation of integrons and antibiotic resistance genes in Danish multiresistant Salmonella enterica Typhimurium DT104; Sandvang D et al.; The presence and genetic content of integrons was investigated in eight Salmonella enteritica Typhimurium DT104 isolates from different pig herds in Denmark . Two different integrons were identified using PCR and sequencing . Each of the integrons carried a single resistance cassette in addition to the sull and qacE delta 1 genes characteristic of integrons . The first integron encoded the ant (3")-1a gene that specified resistance to spectinomycin and streptomycin . The second contained the pse-1 beta-lactamase gene . All the multiresistant strains contained both integrons . The presence of these two integrons did not account for the total phenotypic resistance of all the isolates and does not exclude the presence of other mobile DNA elements.

Ann Acad Med Singapore, 1997 Sep, 26(5), 539 - 43
A shipyard outbreak of salmonellosis traced to contaminated fruits and vegetables; Ooi PL et al.; A large outbreak of food poisoning occurred in September 1996 and involved at least 116 workers at a shipyard in Jurong . Salmonella weltevreden was isolated from the stool specimens of 24 hospitalised cases and three food handlers, giving a total of 27 bacteriologically confirmed cases (25 symptomatic and two asymptomatic) in this outbreak . Based on a case-control analysis, a number of food items consumed on 23 and 24 September 1996 were implicated in the outbreak, viz . a vegetable dish (P < 0.01), watermelon juice (P < 0.01) and cut watermelon (P < 0.001), papaya (P < 0.001) and pineapple (P < 0.05) . The median incubation period was 38 hours and the median duration of illness was two days . Four samples of cut fruits obtained from a food stall at the canteen were found to be positive for Salmonella weltevreden . (The antibiogram of all the strains isolated from food samples and stool cultures was similar, consistent with a common source of infection.) Extensive investigation suggested that contamination may have occurred through unauthorised use of industrial water for washing the fresh produce . Early recognition of the outbreak and prompt implementation of control measures prevented further spread of infection.

Schweiz Arch Tierheilkd, 1998, 140(2), 70 - 5
{Detection of Salmonella enteritidis in suspected flocks of laying hens}; Nief V et al.; 60 birds and environmental samples from 41 suspect flocks (S . enteritidis in faeces or litter, positive serology, close connection with human cases) were investigated to define material and minimal number of birds for detection of infection . S . enteritidis was found in 26/41 (63%) flocks with marked differences in prevalence . S . enteritidis was isolated from ovary (96% of positive flocks), oviduct and liver (87%), spleen (83%), caecal contents (50%) and faeces from the litter floor (57%), but never from egg shells and membranes . As a consequence of this study the bacteriological examination of birds is highly recommended.

Microbiol Immunol, 1997, 41(12), 999 - 1003
Salmonella typhi Ty2 OmpC porin induces bactericidal activity on U937 monocytes; Blanco LP et al.; The immunogenic effect of Salmonella typhi OmpC porin during typhoid fever in humans was evaluated in vitro . Peripheral blood mononuclear cells from 17 patients were challenged with outer membrane preparations from Escherichia coli UH302 and UH302/pSTP2K2 strains, both lacking E . coli OmpF and OmpC porins, although UH302/pSTP2K2 expressed a plasmid-encoded S . typhi Ty2 OmpC . The mononuclear cell supernatants, immunized in vitro with OmpC antigen, derived from 10 out of 17 patients activated U937 bactericidal capacity . In contrast, the supernatants from the immunization with outer membrane preparation lacking S . typhi Ty2 OmpC induced a significantly reduced bactericidal capacity of U937 cells . This procedure should prove useful for in vitro characterization of cellular immunogens from exclusive human pathogens.

Mol Biol Evol, 1998 Jan, 15(1), 6 - 16
Distribution of chromosome length variation in natural isolates of Escherichia coli; Bergthorsson U et al.; Large-scale variation in chromosome size was analyzed in 35 natural isolates of Escherichia coli by physical mapping with a restriction enzyme whose sites are restricted to rDNA operons . Although the genetic maps and chromosome lengths of the laboratory strains E . coli K12 and Salmonella enterica sv . Typhimurium LT2 are highly congruent, chromosome lengths among natural strains of E . coli can differ by as much as 1 Mb, ranging from 4.5 to 5.5 Mb in length . This variation has been generated by multiple changes dispersed throughout the genome, and these alterations are correlated; i.e., additions to one portion of the chromosome are often accompanied by additions to other chromosomal regions . This pattern of variation is most probably the result of selection acting to maintain equal distances between the replication origin and terminus on each side of the circular chromosome . There is a large phylogenetic component to the observed size variation: natural isolates from certain subgroups of E . coli have consistently larger chromosome, suggesting that much of the additional DNA in larger chromosomes is shared through common ancestry . There is no significant correlation between genome sizes and growth rates, which counters the view that the streamlining of bacterial genomes is a response to selection for faster growth rates in natural populations.

Parasitol Res, 1998, 84(1), 63 - 8
Protection of mice previously infected with Plasmodium vinckei against subsequent Salmonella enteritidis infection is associated with nitric oxide production capacity; Lehman LG et al.; When mice previously cured of a Plasmodium vinckei infection were subsequently infected with Salmonella enteritidis the course of bacterial infection was significantly retarded, showing increased survival duration as compared with control infections in naive mice . Moreover, on stimulation with lipopolysaccharide and/or interferon-gamma, spleen cells from malaria-cured mice showed an increased capacity to produce tumor necrosis factor, interleukin 6, and reactive nitrogen intermediates as compared with spleen cells from naive mice . However, no significant variation in the capacity of spleen cells to release reactive oxygen intermediates was observed between previously malarious and naive mice . The most significant increases were observed in the capacity for reactive nitrogen intermediate production after P . vinckei malaria . These results suggest that the observed protection of mice against salmonellosis in the convalescent phase after malaria may be mediated by nitric oxides.

Lett Appl Microbiol, 1998 Jan, 26(1), 47 - 50
Separation of Listeria monocytogenes and Salmonella berta from a complex food matrix by aqueous polymer two-phase partitioning; Pedersen LH et al.; In the present study, the use of aqueous polymer two-phase systems for separation of pathogenic bacteria from a complex food sample was investigated . Three different two-phase systems, a polyethylene glycol 3350/dextran T 500, a methoxy polyethylene glycol 5000/dextran T 500 and a polyethylene glycol 3350/hydroxypropyl starch system, were compared at pH 3 and pH 6 for their capacity to separate the pathogenic bacteria Listeria monocytogenes and Salmonella berta from a Cumberland sausage . In all three phase systems, the food particles partitioned to the lower phase . Best performance was obtained by the polymer combinations, polyethylene glycol 3350/dextran T 500 and polyethylene glycol 3350/hydroxypropyl starch . In these systems, Salmonella berta partitioned to the hydrophobic upper phase both at pH 3 and pH 6 with an average partitioning ratio of 80% and a recovery of 56% . Listeria monocytogenes partitioned to the upper phase at pH 3 only with an average partitioning ratio of 72% and a recovery of 45% . This method may become a valuable tool for separation of bacteria from complex food matrices.

Chem Phys Lipids, 1998 Jan, 91(1), 53 - 69
Characterization of the nonlamellar cubic and HII structures of lipid A from Salmonella enterica serovar Minnesota by X-ray diffraction and freeze-fracture electron microscopy; Brandenburg K et al.; The aggregate structures of lipid A, the 'endotoxic principle' of bacterial lipopolysaccharide (LPS), from rough mutant Salmonella enterica sv . Minnesota R595 was analyzed at different water content, cation (Mg2+) concentration, and temperature applying synchrotron radiation X-ray diffraction and, in selected cases, freeze-fracture electron microscopy . The X-ray diffraction spectra prove the existence of different lamellar, mixed lamellar/cubic, various cubic, and inverted hexagonal (HII) structures depending on ambient conditions . The three mainly bicontinuous cubic phases Q224, Q229, and Q230 can be observed between 30 and 50 degrees C in narrow water and cation concentration ranges . Above 50 degrees C, Q212 an intermediate phase between bicontinuous and micellar is adopted . In freeze-fracture electron microscopic experiments, cubic structures of these symmetries are not readily detected, which can be understood in the light of changes in hydration during freezing and the metastability of these phases . However, 'lipidic particles' closely related to cubic phases are observed . Above 65-70 degrees C, the existence of the HII phase with hexagonal periodicities dH between 4.0 and 6.0 nm for different hydration states is shown using both techniques . Possible biological implications for the preference of lipid A for nonlamellar structures are discussed.

Infect Immun, 1998 Mar, 66(3), 1127 - 34
Salmonella flagellin induces tumor necrosis factor alpha in a human promonocytic cell line; Ciacci-Woolwine F et al.; During infection of the gastrointestinal tract, salmonellae induce cytokine production and inflammatory responses which are believed to mediate tissue damage in the host . In a previous study, we reported that salmonellae possess the ability to stimulate tumor necrosis factor alpha (TNF-alpha) accumulation in primary human monocytes, as well as in the human promonocytic cell line U38 . In this model system, cytokine upregulation is not due to lipopolysaccharide but is mediated by a released protein . In the present study, TnphoA transposon mutagenesis was used to identify the TNF-alpha-inducing factor . A mutant Salmonella strain which lacks the ability to induce TNF-alpha was isolated from a TnphoA library . Genetic analysis of this mutant demonstrated that the hns gene has been interrupted by transposon insertion . The hns gene product is a DNA-binding protein that regulates the expression of a variety of unrelated genes in salmonellae . One of the known targets of histone-like protein H1 is flhDC, the master operon which is absolutely required for flagellar expression . Analysis of other nonflagellated mutant Salmonella strains revealed a correlation between the ability to induce TNF-alpha and the expression of the phase 1 filament subunit protein FliC . Complementation experiments demonstrated that FliC is sufficient to restore the ability of nonflagellated mutant Salmonella strains to upregulate TNF-alpha, whereas the phase 2 protein FljB appears to complement to a lesser extent . In addition, Salmonella FliC can confer the TNF-alpha-inducing phenotype on Escherichia coli, which otherwise lacks the activity . Furthermore, assembly of FliC into complete flagellar structures may not be required for induction of TNF-alpha.

J Paediatr Child Health, 1997 Dec, 33(6), 535 - 8
Salmonella meningitis in children in far north Queensland; Messer RD et al.; Seven cases of Salmonella meningitis have occurred in infants in Far North Queensland since 1982 . The mean age of onset was 2.8 months, and at least five of the cases were caused by Salmonella virchow . Five of the cases had significant complications during the acute illness: all required prolonged (median 34 days) inpatient management, and four developed permanent neurological sequelae . S . virchow is the serovar most frequently isolated from infants in Far North Queensland . The source of S . virchow infections in these infants remains uncertain, but transmission may occur through cross-infection and person-to-person transmission in the home.

Lab Anim, 1998 Jan, 32(1), 42 - 5
Reduction of fever by housing in small cages; Kuhnen G; Housing conditions influence anatomy, physiology, and behaviour of animals . The aim of this study is to investigate whether the generation of fever, a defence response of the body, is also affected by housing conditions . Golden hamsters (Mesocricetus auratus) were housed in small cages, large cages, or large and enriched cages . After 9 weeks of exposure to their respective environments, the fever response to the administration of lipopolysaccharide (50 micrograms/kg from Salmonella typhosa) was tested . One hundred and twenty experiments in 30 hamsters demonstrated that housing in small cages diminished the fever responses (increase in core temperature and fever index) significantly by approximately 20%, and is likely to be due to a higher stress level . The findings demonstrate that the results of physiological experiments are not only influenced by the experimental design, but also by pre-experimental housing conditions.

Schweiz Arch Tierheilkd, 1997, 139(11), 485 - 9
{Salmonella gallinarum-pullorum infection of poultry: experiences in Switzerland}; Hoop RK et al.; 37 Salmonella gallinarum-pullorum-strains were isolated from dead poultry between 1986 and 1996 . All strains except one belonged to the biovar pullorum . 33 isolates were from fancy poultry flocks, four from backyard flocks . 10 of 12 chicks and 10 of 25 adult birds showed clinical signs of disease . The growing significance of fancy and backyard flocks as a reservoir for S . gallinarum-pullorum is emphasized in view of the increase in free range management of commercial layer and broiler flocks.

Mikrobiol Z, 1997 Sep-Oct, 59(5), 83 - 100
{The biological activity of the transfer factor induced by bacterial antigens}; Liubchenko TA et al.; Today's statement of transfer factor, an immunostimulator derived from leukocytes which enhances antiinfectious immunity, is observed in the review . Basic biological, physical and chemical characteristics of the transfer factor, its possible action mechanisms, and laboratory and clinical methods of use to cure infectious fungal (Candida, Coccidium), invasive (schistosomiasis, leishmaniasis, cryptosporidiosis), viral (varicella zoster, ophthalmic herpes, Herpes simplex types 1 and 2, H . zoster, H . simplex ceratitis, genital herpes, human herpes virus type 6, postherpetic neuritis, hepatitis B, AIDS), and bacterial infections (Mycobacterium leprae, M . tuberculosis, M . fortuitum, Salmonella cholerae suis, S . dublin, S . Virchov, Brucella abortus, Actinobacillus pleuropneumoniae, bacterial sepsis, Staphylococcus) are described.

Curr Microbiol, 1998 Jan, 36(1), 29 - 35
Growth, survival and characterization of cspA in Salmonella enteritidis following cold shock; Jeffreys AG et al.; Salmonella enteritidis is a major foodborne microbial pathogen that can grow and survive at low temperatures for a considerable period of time . Increased survival was evidenced from a frozen S . enteritidis culture when treated at 10 degrees C prior to freezing . Western blot analysis with Escherichia coli CspA antibody and analysis of radiolabeled proteins from S . enteritidis cultures after cold shock at 10 degrees C and 5 degrees C showed increased expression of a 7.4-kDa major cold shock protein, CS7.4, similar in size to that reported for E . coli . Cloning followed by nucleotide sequence analysis of the cspA gene from S . enteritidis showed a 100% nucleotide sequence identity in the promoter elements (-35 and -10) and the amino acid sequence encoded by the open reading frame (ORF) with the E . coli cspA gene . However, the differences in the nucleotide sequences between E . coli and S . enteritidis cspA genes in the putative repressor protein binding domain, the fragment 7, and in various segments throughout the upstream 0.642-kbp DNA may contribute to the expression of CS7.4 at less stringent temperatures in S . enteritidis . As in E . coli, the actual role of CS7.4 in protecting S . enteritidis from the damaging effects of cold or freezing temperatures is not yet understood.

Vet Immunol Immunopathol, 1997 Nov, 59(3-4), 359 - 67
Analysis of splenic and thymic lymphocyte subpopulations in chickens infected with Salmonella enteritidis; Sasai K et al.; Lymphocytes expressing CD3, CD4, CD8, pan lymphocyte, IgA, IgG and IgM cell surface antigens were assessed by in the spleen and thymus of chickens following infection with Salmonella enteritidis using flow cytometric analysis . At 6 days post primary infection and 2 days post secondary infection with S . enteritidis, the percentages of IgA+ and IgM+ lymphocytes in the spleen were significantly increased (P < 0.05) . At 2 days post secondary infection with S . enteritidis, the percentage of CD4+ T lymphocyte in the spleen and CD8+ T lymphocyte percentage in the thymus were significantly increased (P < 0.05) . These results indicate that S . enteritidis infection induces changes in the spleen and thymus that reflect the dynamics of the host protective immune response.

Ann Pharmacother, 1998 Jan, 32(1), 51 - 5
Treatment of extravasation from parenteral nutrition solution; Gil ME et al.; OBJECTIVE: To report two cases of parenteral nutrition extravasation and their treatment in adult patients . CASE SUMMARIES: Case 1: A 23-year old white woman was admitted to our hospital diagnosed with a gastrointestinal infection by Salmonella paratyphi sv . B . The treatment included peripheral parenteral nutrition (osmolarity 652 mOsm/L) . After 4 days an extravasation of parenteral nutrition was detected in the left antecubital fossa . The affected area soon became inflamed . Chondroitinsulfatase 150 turbidity-reducing units (TRUs), diluted in 3 mL of NaCl 0.9% and administered in six subcutaneous applications around the area, was prescribed . The treatment was successful . The patient was discharged several days later with no sequelae of the extravasation . Case 2: A 33-year-old white woman was admitted to the intensive care unit after surgery for a necrohemorrhagic pancreatitis . The treatment included parenteral nutrition via a central catheter (osmolarity 2130 mOsm/L) . Two days later the patient presented a parenteral nutrition subcutaneous extravasation in her left hemithorax around the catheter access site . Chondroitinsulfatase 200 TRUs, diluted in 2 mL of NaCl 0.9% and administered in eight subcutaneous applications around the area, was prescribed . No sequelae of the incident remained . The patient was discharged home 2 months later . DISCUSSION: Parenteral nutrition solution can cause tissue harm after extravasation . Both patients presented an intense inflammatory reaction after the accident . Three treatments have been used in extravasation of parenteral nutrition, but in our patients hyaluronidase was the only applicable treatment . As this enzyme is not commercially available in Spain, chondroitinsulfatase, an enzyme very similar to hyaluronidase, was used . CONCLUSIONS: Chondroitinsulfatase was useful in treating extravasation of parenteral nutrition in two adult patients.

J Bacteriol, 1998 Feb, 180(4), 1002 - 7
Relationships among the O-antigen gene clusters of Salmonella enterica groups B, D1, D2, and D3; Curd H et al.; The O antigen is an important cell wall antigen of gram-negative bacteria, and the genes responsible for its biosynthesis are located in a gene cluster . We have cloned and sequenced the DNA segment unique to the O-antigen gene cluster of Salmonella enterica group D3 . This segment includes a novel O-antigen polymerase gene (wzyD3) . The polymerase gives alpha(1-->6) linkages but has no detectable sequence similarity to that of group D2, which confers the same linkage . We find the remnant of a D3-like wzy gene in the O-antigen gene clusters of groups D1 and B and suggest that this is the original wzy gene of these O-antigen gene clusters.

Eur J Gastroenterol Hepatol, 1997 Dec, 9(12), 1239 - 47
Liver involvement in systemic infection; Cook GC; The liver is heavily involved in the vast majority of systemic infections . Pathophysiological mechanisms involved in hepatic involvement in generalized sepsis require further study, as does the importance of bacterial infection in the presence of cirrhosis . Although parasitic involvement is theoretically dominated by Plasmodium spp., in clinical practice Entamoeba histolytica, Schistosoma spp . and Echinococcus spp . infections are far more important . Hepatobiliary involvement is also a feature of Ascaris lumbricoides, Fasciola hepatica and 'oriental' cholangiohepatitis . Various bacteria (including Mycobacterium tuberculosis, Treponema pallidum and Salmonella spp.) and viruses (e.g., cytomegalovirus, Herpes simplex and dengue) also cause significant hepatic involvement . A high index of suspicion for infection is required in paediatric hepatology.

EMBO J, 1997 Dec 15, 16(24), 7231 - 40
Receptor-mediated protein kinase activation and the mechanism of transmembrane signaling in bacterial chemotaxis; Liu Y et al.; Chemotaxis responses of Escherichia coli and Salmonella are mediated by type I membrane receptors with N-terminal extracytoplasmic sensing domains connected by transmembrane helices to C-terminal signaling domains in the cytoplasm . Receptor signaling involves regulation of an associated protein kinase, CheA . Here we show that kinase activation by a soluble signaling domain construct involves the formation of a large complex, with approximately 14 receptor signaling domains per CheA dimer . Electron microscopic examination of these active complexes indicates a well defined bundle composed of numerous receptor filaments . Our findings suggest a mechanism for transmembrane signaling whereby stimulus-induced changes in lateral packing interactions within an array of receptor-sensing domains at the cell surface perturb an equilibrium between active and inactive receptor-kinase complexes within the cytoplasm.

Poult Sci, 1998 Jan, 77(1), 73 - 4
Research notes: Immunohistochemical observations in the ceca of chickens infected with Salmonella enteritidis phage type four; Desmidt M et al.; One-day-old specific-pathogen-free White Leghorn chicks were inoculated orally with Salmonella enteritidis phage type 4 to study adhesion and invasion of the ceca by immunohistochemistry . Positive staining bacilli were associated with the epithelial surface and were present in the lumen of the cecal crypts . They were observed in the interstitial tissue and in the cytoplasm of macrophage-like cells in the lamina propria . A granulomatous nodule containing positive staining bacilli was present in the submucosa of the cecum of one bird at 14 d after inoculation.

Physiol Behav, 1998 Feb 1, 63(3), 377 - 9
Fever in goldfish is induced by pyrogens but not by handling; Cabanac M et al.; Six goldfish, Carassius auratus, weighing 2.5 to 4 g were placed individually in an aquarium with two communicating chambers . One chamber was thermostatted at 34 degrees C, the other at 37 degrees C . In control Session a, without external intervention, fish selected the cooler chamber most of the time and stayed only 4.8 +/- 1.1 min/2 h at 37 degrees C . In Session b, infectious fever was assayed: pyrogen (Salmonella typhosa LPS, or human interleukin-2) was injected intracranially and fish stayed 44.7 +/- 15.3 min/2 h at 37 degrees C . In Session c, behavioral stress was achieved by chasing the fish with a net, catching it, handling it out of water, and injecting 10 microL of saline intracranially . Fish stayed 2.7 +/- 1.0 min/2 h at 37 degrees C . Analysis of variance showed that stay at 37 degrees C was significantly longer in Session b than a and c, and that Sessions a and c were not significantly different from one another . This result confirms the existence of behavioral fever, but does not support the hypothesis of fever in fish after handling.

Crit Care Med, 1998 Feb, 26(2), 322 - 37
Effects of adenosine on cardiopulmonary functions and oxygen-derived variables during endotoxemia; Thiel M et al.; OBJECTIVES: To determine the effects of a prophylactic intravenous infusion of adenosine on cardiopulmonary functions and oxygen-derived variables in a porcine model of endotoxemia . DESIGN: Prospective, randomized, placebo-controlled, unblinded study . SETTING: University research laboratory . SUBJECTS: Thirty country bred pigs, aged 6 to 7 wks, weighing 24.9 +/- 0.65 (SEM) kg body weight . INTERVENTIONS: Pigs were anesthetized by i.v . pentobarbital and fentanyl, intratracheally intubated, and mechanically normoventilated with a gas mixture of nitrous oxide/oxygen = 1:1 . Intravascular catheters were inserted to allow for determination of arterial, central venous blood pressure, pulmonary artery occlusion pressure, cardiac output, and sampling of blood for gas analyses . Group 1 (n = 10) received a 330-min intravenous infusion of Salmonella abortus equi endotoxin (5 microg/kg body weight x hr) . Group 2 (n = 10) received an additional intravenous infusion of adenosine (150 microg/kg body weight x min), started 30 mins before the infusion of endotoxin . Control groups 3 and 4 (n = 5 for both groups) received adenosine or physiologic saline, respectively . MEASUREMENTS AND MAIN RESULTS: Parameters of cardiopulmonary function and oxygen-derived variables were calculated from pulmonary artery catheter measurements and blood gas analyses using standard formula . Plasma concentrations of purine compounds (adenosine, inosine, hypoxanthine) were determined by high-performance liquid chromatography . Since tumor necrosis factor-alpha plays a central role in the development of endotoxic shock, concentrations of this cytokine were determined in serum by enzyme-linked immunosorbent assay . Infusion of adenosine before the beginning of the infusion of endotoxin increased plasma concentrations of the nucleoside from 193 +/- 72 to 553 +/- 65 nmol/L and decreased the systemic vascular resistance by 50% . Although acting as a potent vasodilator under control conditions, adenosine did not aggravate the arterial hypotension elicited by endotoxemia but significantly increased cardiac output by a comparably small decrease in systemic vascular resistance, prevention of pulmonary vasoconstriction, and improvement of left ventricular performance . Despite significant pulmonary vasodilation, gas exchange was not worsened but slightly improved by adenosine . With the increase in cardiac output and arterial oxygenation, systemic oxygen delivery almost doubled . This adenosine-induced oxygen flux was not a surplus but was most likely utilized by tissues, as suggested by the much earlier beginning of the increase in the systemic oxygen consumption and the attenuation of the decrease in the gastric mucosal pHi . No effects of adenosine were observed on the endotoxin-induced increase in serum concentrations of tumor necrosis factor-alpha . CONCLUSIONS: Infusion of adenosine might be useful to improve flow-dependent oxygen delivery and tissue oxygenation during endotoxic shock without the induction of adverse cardiopulmonary side effects . The beneficial hemodynamic effects of adenosine appear not to be mediated by the inhibition of the release of tumor necrosis factor-alpha.

Crit Care Med, 1998 Feb, 26(2), 309 - 14
Inhibition of exhaled nitric oxide production during sepsis does not prevent lung inflammation; Aaron SD et al.; OBJECTIVES: Increases in exhaled nitric oxide have been demonstrated to originate from the lungs of rats after septic lung injury . The aim of this study was to investigate whether treatment with the nitric oxide synthase inhibitor N-nitro-L-arginine methyl ester (L-NAME) would prevent lipopolysaccharide (LPS)-induced increases in exhaled nitric oxide and whether this would have an effect on septic lung inflammation . DESIGN: Prospective, randomized, placebo-controlled animal laboratory investigation . SETTING: University laboratory . SUBJECTS: Male, anesthetized, paralyzed, and mechanically ventilated Sprague-Dawley rats (n = 27) . INTERVENTIONS: Rats were mechanically ventilated with air filtered to remove nitric oxide (expiratory rate 40 breaths/min, tidal volume 3 mL, positive end-expiratory pressure 0, FIO2 0.21) . They were then randomized to receive intravenous injections of either L-NAME (25 mg/kg/hr x 4 hrs) (n = 11) or saline (n = 10) . Both groups were again randomized to receive either LPS (Salmonella typhosa: 20 mg/kg i.v . x 1 dose) or an equal volume of saline 5 mins later . Thereafter, exhaled gas was collected in polyethylene bags for measurements of nitric oxide concentration . After 4 hrs, the rats were killed and the lungs were preserved and examined histologically . To examine the effect of L-NAME and LPS on mean arterial blood pressure, six additional rats underwent the same ventilation protocol with cannulation of the right internal carotid artery so that systemic arterial pressures could be measured . MEASUREMENTS AND MAIN RESULTS: Exhaled gas was collected and measurements of NO concentrations were made using chemiluminescence every 20 mins for 240 mins during ventilation . A total lung injury score was calculated by determining the extent of cellular infiltrate, exudate and hemorrhage . Mean arterial pressure was recorded every 5 mins for 20 mins and then at 20-min periods for 120 mins . Exhaled nitric oxide concentrations increased in all the LPS-treated rats that did not receive L-NAME by 120 mins; a plateau was reached by 190 mins that was approximately 4 times greater than control rats not treated with LPS (p < .001) . In contrast, rats treated with L-NAME and LPS did not show an increase in exhaled NO . Administration of L-NAME induced a 10-min nonsustained increase in mean arterial pressure in two rats treated with L-NAME followed by LPS . This increase in mean arterial pressure was not seen in two placebo and two LPS-treated rats that did not receive L-NAME . Lung inflammation was significantly worse in the two groups of rats which received LPS compared with the two that did not . L-NAME did not cause lung inflammation in rats that did not receive LPS; however, LPS-treated rats that received L-NAME had more inflammatory interstitial infiltrate (p < .05) and a trend toward worse lung injury than did LPS-treated rats that did not receive L-NAME . CONCLUSION: We conclude that L-NAME can inhibit the increase in exhaled NO from the lungs of septic rats, but that this inhibition does not reduce lung inflammation, and may worsen it.

Nahrung, 1997 Dec, 41(6), 359 - 61
Degradation of the natural mutagenic compound safrole in spices by cooking and irradiation; Farag SE et al.; Safrole was determined using gas-liquid chromatography in some common spices as star anise, cumin, black pepper and ginger . Safrole concentration in these spices was 9,325, 3,432, 955 and 500 mg.kg-1, respectively . Black pepper was chosen to use in the following experiments . Using Ames-test with Salmonella TA 98 and TA 100 proved high cytotoxic effects due to pure safrole and black pepper volatile oil in both of them . The degradation of safrole was obvious after drying of the washed seeds of black pepper especially at 70 degrees C for 30 min or with sun-drying . Also, high irradiation doses (20 and 30 kGy) caused high degradation of more than 90% of the initial toxic concentration in black pepper . Whereas, microwave caused same effects at 75 s, but unfortunately, the powder was burned due to moisture absence . Boiling whole seeds or powder of black pepper during cooking for few minutes (1-5 min) were more efficient in decreasing safrole content . Finally, these results proved that the mutagenicity of some spices due to presence of safrole can be destructed during drying of the washed seeds or during cooking either with or without any additional treatment as irradiation . But irradiation of these species became more necessary for using in some food industries as milk products to get more safe for human consumption.

Oral Microbiol Immunol, 1997 Jun, 12(3), 162 - 7
Chemical and biological properties of lipopolysaccharide from Selenomonas sputigena ATCC 33150; Kumada H et al.; Chemical and biological studies were performed on lipopolysaccharide isolated from Selenomonas sputigena ATCC 33150T, a possible causative agent of periodontal diseases . The sugar components of the lipopolysaccharide of S . sputigena were mannose, galactose, glucose, L-glycero-D-mannoheptose (heptose), 2-keto-3-deoxy-octonic acid, glucosamine and galactosamine in a molar ratio of 0.3:1.0:1.0:1.0:0.2:3.0:3.2 (mol/mol heptose) . Sephadex G-50 chromatography of the polysaccharide portion of the lipopolysaccharide obtained by partial hydrolysis yielded three fractions: the O-polysaccharide chain attached to the core oligosaccharide, the core oligosaccharide and monosaccharides . Compositional analysis of these fractions revealed that lipopolysaccharide of S . sputigena carries a short O-polysaccharide chain consisting of galactose and glucosamine and that the core oligosaccharide consisted of glucose, heptose, glucosamine and 2-keto-3-deoxyoctonic acid . It is of particular interest that galactosamine was detected as a component sugar of the lipid A moiety in addition to glucosamine, which is a usual component sugar of the lipid A of most gram-negative bacteria . Thus, the lipid A of S . sputigena might have a unique backbone that differs from that of the lipid A of other gram-negative bacteria . Lipid A of S . sputigena consisted mainly of fatty acids such as undecanoic, tridecanoic, tridecenoic, 3-hydroxytridecanoic and 3-hydroxytetradecanoic acid in a molar ratio of 0.4:1.0:0.3:4.0:0.5 (mol/mol tridecanoic acid) . Lipopolysaccharide and lipid A from S . sputigena both exhibited biological activity in activating the clotting enzyme of Limulus amebocytes, the Schwartzman reaction, mitogenicity for murine lymphocytes and in inducing interleukin-1 alpha and interleukin-6 production in murine macrophages to the same extent as those observed for lipopolysaccharide of the Salmonella serovar typhimurium used as a positive control . The results suggested that the lipopolysaccharide of S . sputigena is a virulent factor in human periodontal diseases.

Mutat Res, 1997 Dec 12, 395(2-3), 139 - 44
Genotoxic activity of important nitrobenzenes and nitroanilines in the Ames test and their structure-activity relationship; Assmann N et al.; The most important commercially available nitro- and aminobenzenes and the explosive trinitrobenzene were tested for mutagenicity in the Salmonella typhymurium TA 98 and TA 100 both in the absence and presence of S 9 . Ten of the 14 compounds tested (71%) were mutagenic . All the substances showed positive results in TA 98 and 4 substances were also mutagenic in TA 100 . The three diaminobenzenes and 4-nitroaniline were mutagenic only with metabolic activation . All other compounds did not require the addition of S 9 . Only nitrobenzene, 1,2-dinitrobenzene, aniline and 2-nitroaniline were negative in both strains . In summary, all substances that are derived from nitrobenzene or aniline by addition of a nitro group in the meta- or para-position were mutagenic, whereas nitrobenzene and aniline themselves and their ortho-derivates were nonmutagenic . The possible relationships between the position of the substituents and the mutagenicity are discussed.

Mutat Res, 1997 Dec 12, 395(2-3), 107 - 12
In vitro genotoxic evaluation of conventional bleached and biobleached softwood pulp mill effluents; Perez-Alzola LP et al.; The effluents of pulp and paper mills contain about 300 different chemical compounds; many of them are mutagens and clastogens . Genotoxic studies have shown that chlorination stage liquors are significantly more genotoxic, in the Ames Salmonella assay, than the other process of lignin extraction, and that lyophilized effluents are genotoxic in cultured mammalian cells . Since these effluents from conventional bleaching stages are genotoxic, Chilean industries are interested in changing this process to a less toxic one, such as biobleaching using enzymes . In this study, we tested the in vitro genotoxicity of two types of effluents: an effluent obtained from a conventional radiata pine kraft-bleaching process (effluent D) and one derived from a biobleaching process with hemicellulase (effluent B) . Both effluents were tested without any concentration or purification steps in the Ames Salmonella assay (TA100) and in the micronuclei (MN) and sister chromatid exchange (SCE) tests in CHO cells . The results showed that neither effluent induced base pair substitution mutations in the Ames Salmonella assay, and neither increased the micronucleus frequency in CHO cells . But, both increased the SCE frequencies in CHO cells, showing that this assay is more sensitive than the other ones, and that the two effluents contained chemical compounds in amounts enough to induce in vitro genotoxicity measured by the SCE induction.

Environ Mol Mutagen, 1998, 31(1), 92 - 6
Prevention of exposure to mutagenic fumes produced by hot cooking oil in Taiwanese kitchens; Chiang TA et al.; We evaluated the mutagens in fumes produced by heating three different cooking oils used in Taiwan to temperatures of 100 degrees C, 200 degrees C, and 300 degrees C, and constructed models to study the efficacy of fume extractors used commonly by Taiwanese women . Particulates of volatile emissions from lard (at 200 degrees C and 300 degrees C) and soybean oil (at 300 degrees C) were found to be mutagenic in the Salmonella/microsomal test with S9 mix, indicating that exposure of Taiwanese women to cooking oil fumes may be an important risk factor in the etiology of their lung cancer . Mutagenicity of lard and soybean oil fumes collected at 300 degrees C was obtained when a commonly used fume extractor was located at a usual distance of 70 cm above the oil surface, whereas the fume samples were not, or weakly, mutagenic in the Salmonella/ microsomal assay when the distance between fume extractor and oil surface was 60 cm or less . Reduction in mutagenicity was on average 1.2 +/- 0.5 revertants/cm (the percent reduction in mutagenicity was 46%), pointing to a possible cooking practice involving significant reductions in exposure to harmful oil fumes and, consequently, a decreased risk of lung cancer in Taiwanese housewives.

Appl Environ Microbiol, 1998 Feb, 64(2), 459 - 64
Biphasic thermal inactivation kinetics in Salmonella enteritidis PT4; Humpheson L et al.; The thermal inactivation kinetics of Salmonella enteritidis PT4 between 49 and 60 degrees C were investigated . Using procedures designed to eliminate methodological artifacts, we found that the death kinetics deviated from the accepted model of first-order inactivation . When we used high-density stationary-phase populations and sensitive enumeration, the survivor curves at 60 degrees C were reproducibly biphasic . The decimal reduction time at 60 degrees C (D60 degrees C) of the tail subpopulation was more than four times that of the majority population . This difference decreased with decreasing temperature; i.e., the survivor curves became more linear, but the proportion of tail cells remained a constant proportion of the initial population, about 1 in 10(4) to 10(5) . Z plots (log D versus temperature) for the two populations showed that the D values coincided at 51 degrees C, indicating that the survivor curves should be linear at this temperature, and this was confirmed experimentally . Investigations into the nature of the tails ruled out genotypic differences between the populations and protection due to leakage from early heat casualties . Heating of cells at 59 degrees C in the presence of 5 or 100 micrograms of chloramphenicol per ml resulted in reductions in the levels of tailing . These reductions were greatest at the higher chloramphenicol concentration . Our results indicate that de novo protein synthesis of heat shock proteins is responsible for the observed tailing . Chemostat-cultured cells heated at 60 degrees C also produced biphasic survivor curves in all but one instance . Cells with higher growth rates were more heat sensitive, but tailing was comparable with batch cultures . Starved cells (no dilution input) displayed linear inactivation kinetics, suggesting that during starvation a rapid heat shock response cannot be initiated.

J Clin Pathol, 1997 Nov, 50(11), 944 - 6
Serological response of patients infected with Salmonella typhi; Chart H et al.; AIMS: To evaluate a rapid immunoblotting procedure for providing evidence of infection with Salmonella typhi using 73 sera from patients infected with S typhi . METHODS: A sodium dodecyl sulphatepolyacrylamide gel electrophoresis (SDS-PAGE)/immunoblotting procedure using lipopolysaccharide (LPS, O = 9,12) and flagellar (H = d) antigens was used . RESULTS: Seventy two of 73 sera contained antibodies to LPS, 40 sera also contained antibodies to H = d flagellar antigens . Analysis of acute and convalescent sera showed that only 62% of patients produced antibodies to flagellar antigens . CONCLUSIONS: The SDS-PAGE/immunoblotting procedure provided a rapid method for providing serological evidence of infection with S typhi.

Ann Rheum Dis, 1997 Nov, 56(11), 671 - 6
Invasion and persistence of Salmonella in human fibroblasts positive or negative for endogenous HLA B27; Huppertz HI et al.; OBJECTIVE: Analysis of the interaction of enteropathogenic bacteria with HLA B27 transfected murine fibroblasts showed a specific influence of HLA B27 on microbial invasiveness . This possible novel mechanism for the action of HLA B27 should be verified by using endogenous HLA B27 positive and negative human fibroblasts as a model for the direct interaction of arthritogenic bacteria and host cells . METHODS: Fibroblasts were obtained from healthy donors positive or negative for HLA B27; cultivated as monolayers; and infected with Salmonella enterica serovar enteritidis . RESULTS: Invasion and survival of bacteria in human cells was not influenced by the presence of HLA B27 . Enhancement of HLA class I molecule expression by treatment of cultures with interferon gamma decreased invasion and survival of bacteria in both HLA B27 positive and negative cells . After disappearance of live bacteria lipopolysaccharide antigens persisted within cells . CONCLUSION: Endogenous HLA B27 does not modulate the direct interaction of Salmonella with human cells . Non-professional phagocytes are able to limit bacterial survival in cells, and interferon gamma accelerates killing of bacteria, but arthritogenic antigens persist after disappearance of live bacteria.

J Cardiovasc Surg (Torino), 1997 Dec, 38(6), 665 - 8
Repair of Salmonella mycotic aneurysm of the paravisceral abdominal aorta using in situ prosthetic graft; Ting AC et al.; Salmonella infection of the abdominal aorta is associated with a high mortality and morbidity, especially when the paravisceral segment is involved . The presentation may be vague and a high index of suspicion is required in order to make the diagnosis early so that prompt treatment can be instituted . Imaging techniques such as computed tomography and angiogram are useful in arriving at a diagnosis as well as planning of operation . The management of a patient with Salmonella mycotic aortic aneurysm includes potent antibiotics, adequate debridement and revascularization . The method of revascularization, in situ bypass or extra-anatomic bypass, has been the subject of controversy . In situ bypass involves placing a graft in an infected field with potentially fatal graft infection, while extra-anatomic bypass has the problem of inferior patency and the necessity of a future reconstruction . We report here a patient with Salmonella mycotic aneurysm of the paravisceral abdominal aorta successfully treated with in situ prosthetic bypass graft.

Cancer Lett, 1997 Dec 9, 120(2), 141 - 7
Antimutagenicity, cytotoxicity and composition of chlorophyllin copper complex; Chernomorsky S et al.; The preparation of chlorophyllin copper complex (CCC), shown to be a tumor promoter in an animal model (Nelson, R.L . (1992) Chlorophyllin, an antimutagen, acts as a tumor promoter in the rat-dimethylhydrazine colon carcinogenesis model . Anticancer Res., 12, 737-740), also inhibits the activities of direct- and indirect-acting mutagens in the Salmonella assay and exhibits cytostatic and cytocidal effects toward myeloma cells . Data from elemental analyses, spectrophotometry and reversed-phase high-performance liquid chromatography indicate that CCC preparations generally used in antimutagenic/anticarcinogenic experiments are variable, complex mixtures of structurally distinct porphyrins lacking copper in some instances . This variability of the composition may be a cause for the differences reported for the tumor promotion activity of CCC.

Rev Med Chil, 1997 Apr, 125(4), 474 - 82
{Typhoid fever in Chile 1977-1990: an emergent disease}; Cabello F et al.; The emergence of old and new communicable diseases is becoming an important public health problem in industrialized and developing countries worldwide . Chile experienced, at the end of the seventies and during the eighties, epidemics of several emergent communicable infectious diseases whose relevance as public health problems had steadily decreased in the previous 25 years . The most striking of these epidemics was a severe outbreak of typhoid fever that lasted at least 10 years . The majority of the cases occurred in the urban setting of Santiago . Several investigators suggested, in light of apparently good sanitation statistics, that factors responsible for this outbreak of typhoid were an increase in the number of chronic carriers of Salmonella typhi, the lack of microbiological food controls and the consumption of vegetables irrigated with waste water contaminated with S typhi . However, there is a dearth of epidemiological information and field work confirming the role of these factors in this typhoid outbreak . Moreover, the sudden, massive and urban characteristics of this epidemic, coupled to contemporary information regarding shortcomings on the preparation of drinking water and on decreased availability of drinking water to the population in Santiago regardless of good sanitation statistics, suggest that this outbreak may have been partially waterborne . The beginning of this typhoid outbreak also coincided with increased rain fall, with rapidly deteriorating economic and social conditions manifested in high rates of unemployment, and with decreased government investment on social services, including sanitation and health . All these factors are known to influence the epidemiology of typhoid and other emergent diseases worldwide.

J Infect, 1997 Nov, 35(3), 308 - 10
Quinolone-resistant Salmonella paratyphi B meningitis in a newborn: a case report; Bhutta ZA; While there are concerns about the consequences of widespread use of quinolones, there are few reports of quinolone-resistant strains of Salmonella typhi or Salmonella paratyphi from the Indian subcontinent . We present a case report of a newborn with meningitis due to a quinolone-resistant strain of S . paratyphi B presenting to the Aga Khan University Hospital (AKUH).

Diagn Microbiol Infect Dis, 1997 Dec, 29(4), 215 - 7
Use of selenite enrichment broth for the detection of Salmonella from stool: a report of one year experience at a provincial public health laboratory; Forward KR et al.; Several references recommend that selenite enrichment be used only in stool cultures from suspect carriers, during outbreaks, and in other special circumstances . To determine the impact of such an approach, we examined results from 3977 specimens cultured by our laboratory . Epidemiological information was collected from physicians and the public health department . Salmonella spp . were identified in 74 specimens from 54 patients . Four Shigella spp . were recovered from four patients . Forty-seven of the 74 Salmonella spp . were recovered on both the primary xylose-lysine-deoxycholate (XLD) and after enrichment . No Salmonella or Shigella grew on the primary XLD only . Twenty-six Salmonella spp . were recovered only after selenite enrichment . Of these, 17 were from newly identified patients . The elimination of selenite enrichment would have significantly reduced our yield, whereas the elimination of the primary XLD would not have resulted in any fewer isolates and would have resulted in savings of approximately $4000 yearly.

Zh Mikrobiol Epidemiol Immunobiol, 1997 Sep-Oct, (5), 88 - 91
{The comparative characteristics of the Salmonella serotypes rarely encountered in the Maritime Territory}; Koval'chuk NI et al.; The results of the comparative study of the phenotypical properties and the plasmid profile of 63 strains of salmonellae, belonging to 44 serotypes of groups B, C1, C2, C3, D, E1, E4, F . The study revealed that strains of different serotypes had their individual plasmid profile . Strains of the same serotype of salmonellae isolated from similar sources had an identical plasmid profile, while strains isolated from different sources differed in their plasmid profiles, though they might have a similar phenotype . Plasmid analysis was shown to be an effective method for the intraspecific typing of rarely isolated Salmonella serotypes and suitable for use as the basis of the microbiological monitoring of salmonellae.

J Clin Microbiol, 1998 Jan, 36(1), 284 - 5
Pulsed-field gel electrophoresis of genomic digests demonstrates linkages among food, food handlers, and patrons in a food-borne Salmonella javiana outbreak in Massachusetts; Lee R et al.; A total of 66 isolates of Salmonella javiana isolated from food, food handlers, and patrons that were epidemiologically linked to an outbreak of gastroenteritis were analyzed by pulsed-field gel electrophoresis . Analysis with restriction endonucleases XbaI and SpeI supported the epidemiologic association and suggested a pathway of transmission among food, food handlers, and patrons.

Mol Microbiol, 1997 Oct, 26(2), 209 - 21
The HtrA family of serine proteases; Pallen MJ et al.; HtrA, also known as DegP and probably identical to the Do protease, is a heat shock-induced serine protease that is active in the periplasm of Escherichia coli . Homologues of HtrA have been described in a wide range of bacteria and in eukaryotes . Its chief role is to degrade misfolded proteins in the periplasm . Substrate recognition probably involves the recently described PDZ domains in the C-terminal half of HtrA and, we suspect, has much in common with the substrate recognition system of the tail-specific protease, Prc (which also possesses a PDZ domain) . The expression of htrA is regulated by a complex set of signal transduction pathways, which includes an alternative sigma factor, RpoE, an anti-sigma factor, RseA, a two-component regulatory system, CpxRA, and two phosphoprotein phosphatases, PrpA and PrpB . Mutations in the htrA genes of Salmonella, Brucella and Yersinia cause decreased survival in mice and/or macrophages, and htrA mutants can act as vaccines, as cloning hosts and as carriers of heterologous antigens.

Zh Mikrobiol Epidemiol Immunobiol, 1995 Jul-Aug, (4), 86 - 7
{The demonstration of specific Salmonella typhi antigens by the latex agglutination method}; Abdurakhmanov AG et al.; The evaluation of the diagnostic importance of the method of latex agglutination with antibody diagnostica for the detection S.typhi O and Vi antigens in biosubstrates obtained from patients is presented . The clinical approbation of the method has made it possible to characterize its diagnostic specificity (whose indices varied from 95.8 to 100%), sensitivity and significant diagnostic effectiveness (67.7-91.3%) . The method has been recommended for the early diagnosis of typhoid fever.

Zh Mikrobiol Epidemiol Immunobiol, 1995 Jul-Aug, (4), 60 - 3
{An assessment of the connection between the annual population morbidity of salmonellosis due to Salmonella enteritidis and the dynamics of the epizootic process among chickens in commercial poultry plants}; Sergevnin VI et al.; The dynamics of annual morbidity in salmonellosis caused by S . enteritidis among the population of Perm during the period of 1987-1992 was analyzed . Blood sera taken from 4,689 practically healthy donors and from 6,997 hens at poultry breeding complexes were studied in the passive hemagglutination test with the use of complex Salmonella diagnosticum . The study revealed that seasonal rises in morbidity caused by S . enteritidis in winter and spring months, as well as in autumn months, were linked with the activation of the epizootic process of Salmonella infection among hens at poultry-breeding complexes during these periods of the year . A rise in the level of anti-Salmonella antibodies in poultry and human blood sera was found to be the precursor of the aggravation of the epidemic situation.

Farmaco, 1997 Jun-Jul, 52(6-7), 359 - 66
Antimicrobial and genotoxic activities of N-hydroxyalkyl-1, 2-benzisothiazol-3(2H)-one carbamic esters; Carmellino ML et al.; N-Hydroxyethyl- and N-hydroxypropyl-1,2-benzisothiazol-3(2H)-one carbamic esters were prepared in order to test their activity against representative bacterial and fungal strains . The obtained results were compared with those reported for parent alcohols and some interesting considerations were drawn . None of the studied derivatives possess genotoxic activity in the Bacillus subtilis rec-assay and Salmonella-microsome test.

Chem Res Toxicol, 1997 Oct, 10(10), 1192 - 7
Identification of the major hepatic DNA adduct formed by the food mutagen 2-amino-9H-pyrido{2,3-b}indole (A alpha C); Pfau W et al.; 2-Amino-9H-pyrido{2,3-b}indole (A alpha C) is among the most prevalent heterocyclic amines detected in grilled or panfried meat; it was shown to be carcinogenic in mice, to induce preneoplastic foci in rat liver, and to form covalent DNA adducts in vitro and in vivo . The corresponding nitro compound 2-nitro-9H-pyrido{2,3-b}indole (N alpha C) was prepared and shown to be a direct acting mutagen in the Salmonella assay, while the amino compound required external metabolic activation with rat liver homogenate (S9) . When A alpha C was incubated with S9 in the presence of calf thymus DNA, one major DNA adduct spot was detected upon 32P-postlabeling analysis . This adduct comigrated on ion-exchange TLC and reversed-phase HPLC with the major adduct detected in primary hepatocytes treated with A alpha C . In DNA isolated from livers of male F344 rats treated with 800 and 160 ppm, the formation of the same major adduct was observed with relative adduct levels of 20.6 +/- 9.6 and 1.4 +/- 1.1 adducts/10(8), respectively, as determined with the butanol extraction variant of the 32P-postlabeling assay . No DNA adducts were detected in liver DNA from rats treated with 32 ppm A alpha C or control animals . The major adduct spot was eluted and hydrolyzed and the modified base characterized by chromatographic and UV spectral comparison with a synthetic standard synthesized from acetylated guanine N3-oxide and A alpha C . Electrospray mass spectrometry and 1H- and 13C-NMR spectroscopy provided further evidence for the major adduct as N2-(guanin-8-yl)-2-amino-9H-pyrido{2,3-b}indole . A alpha C is formed especially in high-temperature preparation of food and may contribute considerably to the human carcinogenic risk that might be imposed by heterocyclic amines.

J Bacteriol, 1998 Feb, 180(3), 762 - 5
A functional homolog of Escherichia coli NhaR in Vibrio cholerae; Williams SG et al.; Escherichia coli NhaR controls expression of a sodium/proton (Na+/H+) antiporter, NhaA . The Vibrio cholerae NhaR protein shows over 60% identity to those of Escherichia coli and Salmonella enteritidis . V . cholerae NhaR complements an E . coli nhaR mutant for growth in 100 mM LiCl-33 mM NaCl, pH 7.6, and enhances the Na+-dependent induction of an E . coli chromosomal nhaA::lacZ fusion . These findings indicate functional homology to E . coli NhaR . Two V . cholerae nhaR mutants were constructed by using kanamycin resistance cartridge insertion at different sites to disrupt the gene . Both mutants showed sensitivity to growth in 120 mM LiCl, pH 9.2, compared with the wild-type strain and could be complemented by the introduction of V . cholerae nhaR on a low-copy-number plasmid . An nhaR mutation had no detectable effect on the virulence of the V . cholerae strain in the infant mouse model, suggesting that the antiporter system involved is not required in vivo, at least in this animal model.

J Bacteriol, 1998 Feb, 180(3), 614 - 21
Genetic determinants of immunity and integration of temperate Myxococcus xanthus phage Mx8; Salmi D et al.; An 8.1-kb fragment of the temperate Myxococcus xanthus phage Mx8 genome, when cloned into a plasmid vector, permits site-specific integration of the plasmid and confers superinfection immunity . Sequence analysis of a 9.5-kb region of Mx8 DNA containing this fragment reveals 19 densely packed open reading frames, four of which have predicted products with known or suspected activities . The Mx8 imm gene, required for superinfection immunity, has a sequence similar to that of Arabidopsis thaliana G-box-binding factor 1 . Mx8 makes a DNA adenine methylase, Mox, and integrase, Int, related to other methylases and integrases . The int gene has two alternate translation initiation codons within the extensively overlapping uoi (upstream of int) gene . Comparison of the predicted product of the uoi gene with Salmonella phage P22 and Streptomyces plasmid Xis proteins shows that temperate phage excisionases may use variations of a helix-turn-helix motif to recognize specific DNA sequences.

Infect Immun, 1998 Feb, 66(2), 682 - 91
Environmental regulation of Salmonella typhi invasion-defective mutants; Leclerc GJ et al.; Salmonella typhi is the etiologic agent of human typhoid . During infection, S . typhi adheres to and invades epithelial and M cells that line the distal ileum . To survive in the human host, S . typhi must overcome numerous complex extracellular and intracellular environments . Since relatively little is known about S . typhi pathogenesis, studies were initiated to identify S . typhi genes involved in the early steps of interaction with the host and to evaluate the environmental regulation of these genes . In the present study, TnphoA mutagenesis was used to study these early steps . We isolated 16 Salmonella typhi TnphoA mutants that were defective for both adherence and invasion of the human small intestinal epithelial cell line Int407 . Twelve of sixteen mutations were identified in genes homologous to the S . typhimurium invG and prgH genes, which are known to be involved in the type III secretion pathway of virulence proteins . Two additional insertions were identified in genes sharing homology with the cpxA and damX genes from Escherichia coli K-12, and two uncharacterized invasion-deficient mutants were nonmotile . Gene expression of TnphoA fusions was examined in response to environmental stimuli . We found that the cpxA, invG, and prgH genes were induced when grown under conditions of high osmolarity (0.3 M NaCl) . Expression of invG and prgH genes was optimal at pH 6.5 and strongly reduced at low pH (5.0) . Transcription of both invG and prgH TnphoA gene fusions was initiated during the late logarithmic growth phase and was induced under anaerobic conditions . Finally, we show that both invG and prgH genes appear to be regulated by DNA supercoiling, a mechanism influenced by environmental factors . These results are the first to demonstrate that in S . typhi, (i) the prgH and cpxA genes are osmoregulated, (ii) the invG gene is induced under low oxygen conditions, (iii) the invG gene is pH regulated and growth phase dependent, and (iv) the prgH gene appears to be regulated by DNA supercoiling . Since our experimental conditions were designed to mimic the in vivo environmental milieu, our results suggest that specific environmental conditions act as signals to induce the expression of S . typhi invasion genes.

Infect Immun, 1998 Feb, 66(2), 399 - 405
Complementary recognition of alternative pathway activators by decay-accelerating factor and factor H; Kraus D et al.; The alternative complement pathway (ACP) functions as a surveillance mechanism by which microorganisms are opsonized with C3b in the absence of specific antibodies . The effectiveness of the ACP relies on its ability to distinguish self from non-self . This recognition function is mediated by C3 regulatory proteins including serum factor H, membrane cofactor protein (MCP), and membrane decay-accelerating factor (DAF) . H activity against bound C3b can be increased by host components such as sialic acid and decreased by microbial polysaccharides . DAF and MCP may also recognize cell surface changes such as the presence of viral glycoproteins, since some virus-infected and tumor cells activate the ACP . In the present study, liposomes containing wild-type and mutant Salmonella minnesota lipopolysaccharide (LPS) were tested for ACP activation in serum . LPS-containing liposomes with bound C3b were then tested for their susceptibility to C3 convertase regulation by H and membrane DAF and for the sensitivity of their bound C3b to the cofactor activity of H . The results indicate that while the shortest mutant, Re595 LPS, did not induce ACP activation, R7 LPS containing an additional disaccharide did . This activation was poorly regulated by DAF but was inhibited by H . The regulatory activity of H for liposome-bound C3b, however, decreased when LPS of greater polysaccharide size was present in the membrane . In contrast the ACP activation induced by the phospholipid phosphatidylethanolamine was effectively inhibited by DAF but only poorly inhibited by H.

FEMS Immunol Med Microbiol, 1997 Nov, 19(3), 215 - 21
Genetic typing methods applied to the differentiation of clonal lines among Salmonella enterica serogroup G strains causing human salmonellosis; Martin MC et al.; In Spain, in November 1995, an epidemiological alert recommended the surveillance of Salmonella serogroup G . The nine clinical isolates collected after and the four collected before the alert in Asturias were differentiated into six clonal lines by the combination of results from HincII ribotyping, PCR ribotyping, and RAPD typing using primers named A and S . The seven Gumpensis isolates showed identical DNA fingerprinting with the four typing procedures falling into a line . Six of these were collected during May-August from people living in a single health area suggesting that they could be associated with a community outbreak . The four Worthington isolates fell into three other lines, one Poona isolate into another line and one Havana isolate into another . 100% typeability was shown with all methods . The reproducibility of HincII ribotyping was better than that of PCR-based methods, although these were less time-consuming . The highest discriminatory power was obtained with HincII ribotyping and RAPD typing using primer A.

FEMS Immunol Med Microbiol, 1997 Nov, 19(3), 191 - 202
Characterization of serum antibody response to chlamydiae in patients with sexually acquired reactive arthritis; Domeika K et al.; Sera from patients with sexually acquired reactive arthritis (SARA) with antibodies reacting with C . trachomatis and C . pneumoniae (group 1; n = 20) and also with C . psittaci (group 2; n = 19) were analyzed for antibody specificity . Sera from group 2 reacted significantly more often with C . trachomatis serotype E, H and K and had higher antibody titers to serotype E, as tested by microimmunofluorescence tests . Cross-reactivities occurring in microimmunofluorescence tests were related to the presence of antichlamydial lipopolysaccharide antibodies, adsorption of which by recombinant lipopolysaccharide removed microimmunofluorescence reactivity with C . psittaci antigen . In group 2, significantly more sera had antibodies to C . pneumoniae, remaining after lipopolysaccharide adsorption, as proved by adsorption with viable C . trachomatis and C . pneumoniae organisms . None of the sera had antibodies to Yersinia enterocolitica, Shigella flexneri, Sh . sonnei and Salmonella spp . It was observed that the frequency and titer of cross-reacting antibodies to chlamydial serotypes and species were related to the time period between the diagnosis of genital chlamydial infection and of SARA . Cross-reactivities were also related to the presence of lipopolysaccharide, but not heat shock protein 60- or neutralizing antibodies to chlamydiae . Antibody reactivity induced by antichlamydial lipopolysaccharide antibodies can be removed by lipopolysaccharide adsorption.

Vet Microbiol, 1997 Nov, 58(2-4), 277 - 93
Bacteriological and serological investigation of persistent Salmonella enteritidis infection in an integrated poultry organisation; Davies RH et al.; Bacteriological monitoring of broiler breeder farms, the hatchery, rendering plant and animal feed mill during 1991 identified a number of potential cross-contamination hazards, such as the use of processed poultry proteins in the company feed mill and contamination of egg trolleys and trays, which may have led to widespread dissemination of Salmonella enteritidis within an integrated poultry organisation . Serological monitoring of the flocks suggested that, in most cases, substantial exposure to S . enteritidis infection occurred during the mid-rearing stage whereas routine bacteriological monitoring of poultry house litter and dust samples, and meconium samples taken in the hatchery identified infection only after the onset of the laying period . At least 10 phage types and six plasmid profile types of S . enteritidis were identified in historic submissions from the organisation including one apparently specific plasmid profile type that was distributed throughout the various parts of the company . During sampling for this investigation, most of these strains were not identified, and the number of plasmid profile types was reduced to a single common UK type.

Clin Infect Dis, 1997 Dec, 25(6), 1404 - 10
Quinolone-resistant Salmonella typhi in Viet Nam: molecular basis of resistance and clinical response to treatment; Wain J et al.; Nalidixic acid-resistant Salmonella typhi (NARST) was first isolated in Viet Nam in 1993 . Analysis of the quinolone resistance-determining region of gyrA in 20 NARST isolates by polymerase chain reaction and single-stranded conformational polymorphism yielded two novel patterns: pattern II corresponding to a point mutation at nucleotide 87 Asp-->Gly (n = 17), and pattern III corresponding to a point mutation at nucleotide 83 Ser-->Phe (n = 3) . In trials of short-course ofloxacin therapy for uncomplicated typhoid, 117 (78%) of 150 patients were infected with multidrug-resistant S . typhi, 18 (15%) of which were NARST . The median time to fever clearance was 156 hours (range, 30-366 hours) for patients infected with NARST and 84 hours (range, 12-378 hours) for those infected with nalidixic acid-susceptible strains (P < .001) . Six (33.3%) of 18 NARST infections required retreatment, whereas 1 (0.8%) of 132 infections due to susceptible strains required retreatment (relative risk = 44; 95% confidence interval = 5.6-345; P < .0001) . We recommend that short courses of quinolones not be used in patients infected with NARST.

J Biol Chem, 1998 Jan 2, 273(1), 653 - 9
Activation of the leu-500 promoter by a reversed polarity tetA gene . Response to global plasmid supercoiling; Chen D et al.; The leu-500 promoter is inactivated by a mutation in the -10 region but can be activated in topA Escherichia coli and Salmonella strains . We have found that the tetA gene plays a vital role in the topA-dependent activation of a plasmid-borne leu-500 promoter . In previous studies, the leu-500 promoter and tetA gene have been arranged divergently . In this study we have reversed the polarity of the tetA gene, thus locating the leu-500 promoter at the 3' end of tetA . Despite being formally located in the downstream region of tetA, the leu-500 promoter is equally well activated in a topA strain in this environment, even though it is 1.6 kilobase pairs away from the promoter of the reversed tetA gene . Activation of the leu-500 promoter depends on transcription and translation of tetA but is largely insensitive to the function of other transcription units on the plasmid . These results require a change in viewpoint of the role of tetA, from local to global supercoiling . We conclude that transcription of the tetA gene is the main generator of transcription-induced supercoiling that activates the leu-500 promoter . Unbalanced relaxation of this supercoiling leads to a net increase in the negative linking difference of the plasmid globally, and there is a linear correlation between the change in global plasmid topology and the activation of the leu-500 promoter . Thus the leu-500 promoter appears to respond to the negative supercoiling of the plasmid overall.

Proc Natl Acad Sci U S A, 1997 Dec 23, 94(26), 14456 - 60
D-myo-Inositol 1,4,5,6-tetrakisphosphate produced in human intestinal epithelial cells in response to Salmonella invasion inhibits phosphoinositide 3-kinase signaling pathways; Eckmann L et al.; Several inositol-containing compounds play key roles in receptor-mediated cell signaling events . Here, we describe a function for a specific inositol polyphosphate, D-myo-inositol 1,4,5,6-tetrakisphosphate {Ins(1,4,5,6)P4}, that is produced acutely in response to a receptor-independent process . Thus, infection of intestinal epithelial cells with the enteric pathogen Salmonella, but not with other invasive bacteria, induced a multifold increase in Ins(1,4,5,6)P4 levels . To define a specific function of Ins(1,4,5,6)P4, a membrane-permeant, hydrolyzable ester was used to deliver it to the intracellular compartment, where it antagonized epidermal growth factor (EGF)-induced inhibition of calcium-mediated chloride (Cl-) secretion (CaMCS) in intestinal epithelia . This EGF function is likely mediated through a phosphoinositide 3-kinase (PtdIns3K)-dependent mechanism because the EGF effects are abolished by wortmannin, and three different membrane-permeant esters of the PtdIns3K product phosphatidylinositol 3,4,5-trisphosphate mimicked the EGF effect on CaMCS . We further demonstrate that Ins(1,4,5,6)P4 antagonized EGF signaling downstream of PtdIns3K because Ins(1,4,5, 6)P4 interfered with the PtdInsP3 effect on CaMCS without affecting PtdIns3K activity . Thus, elevation of Ins(1,4,5,6)P4 in Salmonella-infected epithelia may promote Cl- flux by antagonizing EGF inhibition mediated through PtdIns3K and PtdInsP3.

Lett Appl Microbiol, 1997 Dec, 25(6), 447 - 52
Expression of SEF17 fimbriae by Salmonella enteritidis; Dibb-Fuller M et al.; Specific immunological reagents were used to investigate the expression of SEF17 fimbriae by cultured strains of Salmonella enteritidis . Most strains of Salm . enteritidis tested expressed SEF17 when cultured at temperatures of 18-30 degrees C . However, two wild-type strains produced SEF17 when also grown at 37 degrees C and 42 degrees C . Colonization factor antigen agar was the optimum medium for SEF17 expression, whereas Drigalski and Sensitest agars poorly supported SEF17 production . Very fine fimbriae produced by a strain of Salm . typhimurium were specifically and strongly labelled by SEF17 monoclonal and polyclonal antibodies, indicating considerable antigenic conservation between the two . Curli fimbriae from Escherichia coli were similarly labelled . The production of these fimbriae correlated with the binding of fibronectin by the organism . Congo red binding by cultured bacteria was not a reliable criterion for the expression of SEF17 fimbriae.

J Appl Microbiol, 1997 Dec, 83(6), 727 - 36
A universal protocol for PCR detection of 13 species of foodborne pathogens in foods; Wang RF et al.; A universal protocol for PCR detection of 13 species of foodborne pathogens in foods was developed . The protocol used a universal culture medium and the same PCR conditions with 13 sets of specific primers . The 13 species of foodborne pathogens examined were Escherichia coli, E . coli-ETEC, E . coli-O157:H7, Shigella spp., Salmonella spp., Yersinia enterocolitica, Y . pseudotuberculosis, Vibrio cholerae, V . parahaemolyticus, V . vulnificus, Listeria monocytogenes, Staphylococcus aureus and Bacillus cereus . No interference was observed using the PCR assay when food sample was artificially inoculated with each individual bacterial species . Twelve different seafood samples and two soft cheese samples without artificial inoculation were examined by this protocol . Vibrio vulnificus, Salmonella spp., E . coli, Listeria monocytogenes and Bacillus cereus were detected in some foods . Internal probe hybridization and nested PCR procedures were used to confirm the above findings.

J Air Waste Manag Assoc, 1997 Dec, 47(12), 1250 - 8
Toxicity and mutagenicity of component classes of oils isolated from soils at petroleum- and creosote-contaminated sites; Zemanek MG et al.; Microtox and Ames bioassays were employed to assess acute toxicity and mutagenicity of water soluble components of class-fractionated oils extracted from one creosote- and four petroleum-contaminated soils . Microtox results revealed that potential acute toxicity resides mainly in the polar class fractions at three sites and indicated potential synergistic and antagonistic effects between compounds in the total extracts at two sites . Ames Salmonella/microsome testing indicated that the polyaromatic fractions at two sites exhibit weak mutagenicity with enzymatic activation, while the polar fractions at two sites are weakly mutagenic without enzyme activation . Further chemical characterization of the polar and polyaromatic fractions is required to fully assess the potential of health and ecological risks at the creosote-and petroleum-contaminated sites exhibiting these toxic responses.

Eur J Clin Microbiol Infect Dis, 1997 Nov, 16(11), 803 - 6
Comparison of two regimens for ciprofloxacin treatment of enteric infections; Agalar C et al.; A clinical trial was conducted in 50 patients with blood cultures positive for Salmonella typhi or Salmonella paratyphi to compare treatment with ciprofloxacin for seven days, 500 mg b.i.d . (Group 1, 25 patients), with treatment for ten days, 750 mg b.i.d . (Group 2, 25 patients) . Clinical cure was defined as defervescence of fever by day 5 of treatment, with an absence of complications and no clinical relapse . The clinical cure rate was 84% for group 1 and 96% for group 2; the difference in these rates was not statistically significant . The blood cultures of all patients were sterile by day 2 of treatment and remained so until the sixth month of follow-up . It was concluded that ciprofloxacin treatment for ten days in enteric fever is not necessary . Further studies are needed to evaluate the efficacy of shortening the duration of antibiotic therapy.

Ugeskr Laeger, 1997 Dec 29, 160(1), 54 - 5
{Gluteal hematoma infected with multiresistant Salmonella typhi}; Lindberg JA et al.; Salmonella infections usually presents with diarrhea and fever . Localized salmonella infection with abscess formation is an uncommon but significant manifestation of salmonellosis . An infected gluteal haematoma caused by multi resistant Salmonella typhi is described . Etiologic diagnosis, appropriate chemotherapy, surgical intervention and isolation is important . There was no nosocomial infections related to this case and treatment was effective . It is important to be aware of unusual manifestations of salmonella infections, which may occur without any previous history of exposure.

Ugeskr Laeger . 1997 Dec 29;160(1):53.
{Deep wound infection with Salmonella enteritidis following osteosynthesis}; Zerahn B et al.; A 43-year old man with alcohol abuse had septicaemia with Salmonella enteritidis . After osteosynthesis of an intertrochanteric femoral fracture he developed a deep wound infection with Salmonella enteritidis . The patient was treated with surgical debridement and antibiotics . As a consequence of alcohol abuse the patient may have had a predisposing immunosuppression, and infection with Salmonella enteritidis should be considered in case of postoperative infection in these patients.

Am J Respir Crit Care Med, 1998 Jan, 157(1), 273 - 9
The role of endogenous nitric oxide in modulating ischemia-reperfusion injury in the isolated, blood-perfused rat lung; Lu YT et al.; Ischemia-reperfusion (IR) lung injury occurs after various clinical procedures, including cardiopulmonary bypass . It is not clear whether endogenous nitric oxide (NO) is protective or injurious in lungs subjected to IR . Thus, in this study we examined the contribution of endogenous NO to IR injury in isolated, blood-perfused rat lungs . Lungs of male Wistar rats (300 g) were subjected to 30 min ischemia and 180 min reperfusion (I30R180) . Lungs were sampled for inducible nitric oxide synthase (i-NOS) mRNA expression (each n = 3) and NOS enzyme activity (each n = 4) at different time points . NOS inhibitors NG-nitro-L-arginine-methyl ester (10{-4} M) and aminoguanidine (10{-4} M) were used to study the contribution of NO to IR injury in lungs subjected to I30R30 and I30R180 . The contribution of i-NOS to IR lung injury was studied by inducing i-NOS enzyme with Salmonella lipopolysaccharide, followed by I30R30 . We found that ischemia-reperfusion alone can upregulate i-NOS mRNA and i-NOS enzyme activity (p < 0.05, ANOVA), but downregulate constitutive NOS enzyme activity over 180 min reperfusion . Endogenously produced NO is protective against lung injury in I30R180 in normal rats and lung injury in I30R30 in septic rats . NO is also pivotal in maintaining pulmonary vascular homeostasis in septic rat lungs undergoing IR.

Microb Drug Resist, 1997 Winter, 3(4), 339 - 43
Antibiotic-resistant Salmonella typhi from two outbreaks: few ribotypes and IS200 types harbor Inc HI1 plasmids; Fica A et al.; To investigate factors that could be involved in the emergence of antibiotic resistant S . typhi, we characterized R plasmids and antibiotic resistant S . typhi strains from two outbreaks of typhoid in Peru and Chile . Differences in the Inc HI1 plasmids of Peruvian and Chilean strains were identified by conjugation and incompatibility studies and plasmid DNA characterization . Antibiotic-resistant S . typhi harboring Inc HI1 plasmids belonged to a reduced number of Pst1 and Cla1 ribotypes and IS200 types, in contrast to the high genetic diversity found among epidemic antibiotic-susceptible S . typhi . The low diversity of antibiotic-resistant S . typhi suggests that they may express properties that are related to both their ability to harbor Inc HI1 R plasmids and to disseminate.

Insect Biochem Mol Biol, 1997 Aug-Sep, 27(8-9), 711 - 20
Protein purification and cDNA cloning of a cecropin-like peptide from the larvae of fall webworm (Hyphantria cunea); Park SS et al.; A proteinous antimicrobial substance was purified from the bacteria-challenged larvae of the fall webworm, Hyphantria cunea . It is a cecropin-like antibacterial peptide which exhibits antibacterial activity against Gram-negative and Gram-positive bacteria, and known as Hyphantria cecropin A . The cDNA clones corresponding to this peptide were isolated from a cDNA library constructed from the bacteria-challenged larvae and obtained complete nucleotide sequences . In addition to the Hyphantria cecropin A sequence, we obtained three other cDNAs exhibiting high sequence similarity with Hyphantria cecropin A . We synthesized the C-terminally amidated peptide of 35 residues based on the deduced sequence of the isolated cDNA of Hyphantria cecropin A . The synthetic peptide exhibited strong antibacterial activity against several microbes including medically important bacteria such as Salmonella, Shigella, and fungus such as Candida . A Southern blot experiment using these cloned cDNAs as probes predicted the existence of multiple forms of Hyphantria cecropin genes.

Can J Vet Res, 1998 Jan, 62(1), 27 - 32
Evaluation of oral, subcutaneous, and nasal administration of Salmonella enteritidis-immune lymphokines on the potentiation of a protective heterophilic inflammatory response to Salmonella enteritidis in day-old chickens; Kogut MH et al.; We have previously reported that the prophylactic administration of factor(s) from T-cell supernatants derived from Salmonella enteritidis-immune chickens (ILK) have a favorable effect in controlling or eliminating salmonellosis in neonatal poultry . Experimentally, we have used the intraperitoneal injection as the standard method of administering ILK to neonatal poultry . However, this method is neither easy, practical, nor economical for the poultry industry . In the present study, we evaluated the effectiveness of oral (p.o.), intranasal (i.n.), and subcutaneous (s.c.) administration of ILK for ease of delivery, induction of protective resistance against Salmonella enteritidis (Se) organ invasion, and the ability to activate peripheral blood heterophils in day-old chickens . In the first experiments, delivery of ILK p.o., i.n., and s.c . significantly (P < 0.01) increased the resistance of day-old chickens to Se organ invasion . The level of protection was equivalent to that induced by the i.p . route . Administration of a comparable protein control (bovine serum albumin, BSA) by the 3 routes induced no protective effect against Se organ invasion . Likewise, a significant increase was found in the number of circulating heterophils within 4 h of administration of the ILK by all routes . In the 2nd experiment, the function of the heterophils from ILK-treated birds was compared with that of the control cells in adherence, chemotaxis, and phagocytosis assays . The heterophils from birds given ILK i.p., s.c., p.o., or i.n . had significantly (P < 0.01) increased functional activities when compared to the activities of the heterophils from the control birds . These studies indicate that the delivery of ILK either orally or parenterally, routes which can be used by the poultry industry, can confer protection to chickens against a localized enteric Se organ invasion by potentiating the systemic heterophilic innate response.

J Antibiot (Tokyo), 1997 Mar, 50(3), 246 - 55
Correlation of susceptibility and resistance of twenty-five bacterial strains by analysis of MIC database of cephalosporins and oxacephalosporins
Kodama Y, Inouye S.
MIC database of 1,407 cephalosporins and oxacephalosporins was utilized to characterize 25 bacterial strains including Gram-positive and Gram-negative bacteria . MIC values were converted to activity rank indices, and distribution patterns of these indices were compared among the bacterial strains . Salmonella enteritidis No . 11 was the most susceptible bacterium, and the activity against this strain was ascribed to the binding of beta-lactams to the PBPs without any significant barrier to the approach of beta-lactams . Twenty-one strains were assumed to have similar types of PBPs to those of S . enteritidis No . 11 in the binding profile to beta-lactams . Comparison of the scatter diagrams of the activity rank indices revealed two different types of resistances arising from beta-lactamases (9 strains) and outer membrane permeability and/or active efflux (15 strains) . The resistance factor arising from beta-lactamase was affected by the nature of the C-3 substituents of beta-lactams.

Trop Gastroenterol, 1997 Jul-Sep, 18(3), 134 - 5
Splenic abscess--case report and review of literature; Sinha S et al.; Isolated splenic abscess is a rarity and remains a diagnostic dilemma . The presentation is nonspecific and diagnosis is often delayed . We present a case which had roentgenographic signs suggestive of splenic suppuration at admission . Of particular interest was the isolation of Salmonella paratyphi in this patient . Antibiotic therapy alone is insufficient and splenectomy remains the treatment of choice . The literature on splenic abscess is briefly reviewed.

Trop Med Int Health, 1997 Dec, 2(12), 1140 - 2
Pleural empyema due to Salmonella paratyphi in a patient with AIDS; Wolday D et al.; Pleural empyema due to Salmonella has rarely been reported in immunocompromised patients . Here, we present a case of a 25-year old man infected with the human immunodeficiency virus type-1 (HIV-1) who presented with a left-sided pleural effusion . The cause was confirmed bacteriologically to be due to Salmonella paratyphi . The outcome was favourable after antibiotic therapy coupled with pleural drainage . It should be recognised that pleural empyema due to Salmonella may occur in HIV-infected subjects and we suggest that patients presenting with pleural empyema due to uncommon pathogens be tested for HIV-1 antibodies.

Eur J Med Res, 1996 Nov 25, 1(12), 589 - 90
Salmonella infection and pneumonia in a patient with kyphoscoliosis; Yossepowitch O et al.; Pulmonary involvement is an uncommon extraintestinal manifestation of salmonellosis . We describe a 30 year old man with mental retardation, presenting with salmonella gastroenteritis and bacteremia . An early pneumonia evolving in the clinical setting of severe kyphoscoliosis, suggests that hematogenous spread to the lungs may occur as a result of abnormalities of the chest wall.

Rinsho Byori, 1997 Dec, 45(12), 1167 - 71
{Validation of three limulus tests for the determination of endotoxin in dialysate/substitute used in on-line hemodiafiltration}; Yamamoto C; The on-line hemodiafiltration, a newly developed technic of artificial kidney, requires a large mount of dialysate as a substitute for filtered plasma . The dialysate is prepared in the hospital, and is liable to be contaminated . To avoid adverse effects from contaminants, the dialysate needs to be checked at least for endotoxin (ET) with a highly sensitive, accurate and precise method . Three commercial kits, Endospecy (Seikagaku, Tokyo), ES-single (Wako, Osaka) and QCL (BioWhittacker, Maryland), were tested to see if they receive any interference from dialysate . The recoveries of Escherichia coli and Salmonella ET spiked in dialysate at final concentrations of 50, 100 and 150 EU/l were evaluated against those spiked in distilled water using simple linear regression analysis . The validation criteria was that the coefficient of a regression line which was forced to pass through the origin should fall between 0.75 and 1.25 . No interference was observed with Endospecy . The QCL showed no interference with E . coli ET but enhancement with Salmonella ET . The ES-single was least sensitive for either ET . Dilution of dialysate affected the recoveries by QCL and ES-single but not those by Endospecy . The Endospecy was thus the only reagent that could detect ET level as low as 1.0 EU/l without interference from dialysate . The rise in body temperature after 4-hour on-line hemodiafiltration was correlated with ET level in the substitution fluid (r = 0.48, p < 0.05), and was significant when the level was 1.0 EU/l or more . These results suggest that the ET level of substitution fluid should be monitored with Endospecy and that the level should be kept below 1.0 EU/l.

Environ Mol Mutagen, 1997, 30(4), 440 - 7
Glutathione S-transferase-mediated induction of GC-->AT transitions by halomethanes in Salmonella; DeMarini DM et al.; Halomethanes are among the most common mutagenic and carcinogenic disinfection by-products present in the volatile/semivolatile fraction of chlorinated drinking water . Recent studies have demonstrated that the mutagenicity of dichloromethane (CH2Cl2) and bromodichloromethane (BrCHCl2) can be mediated by a theta-class glutathione S-transferase (GSTT1-1) . These studies used strain RSJ100 of Salmonella, which is a derivative of the base-substitution strain TA1535 (hisG46, rfa, delta uvrB), into which has been cloned the GSTT1-1 gene from rat . In the present report, we have extended these studies by demonstrating that the mutagenicity of two additional brominated trihalomethanes, bromoform (CHBr3) and chlorodibromomethane (CICHBr2), are also mediated by GSTT1-1 in RSJ100 . Using a Tedlar bag vaporization technique, the mutagenic potencies (revertants/ppm) for these two compounds as well as the compounds tested previously rank as follows: CHBr3 approximately CICHBr2 > BrCHCl2 approximately CH2Cl2 . To explore the mutational mechanism, we determined the mutation spectra of all four halomethanes at the hisG46 allele by performing colony probe hybridizations of approximately 100 revertants induced by each compound . The majority (96-100%) of the mutations were GC-->AT transitions, and 87-100% of these were at the second position of the CCC/GGG target . In contrast, only 15% of mutants induced by CH2Cl2 were GC-->AT transitions in the absence of the GSTT1-1 gene in strain TA100 (a homologue of TA1535 containing the plasmid pKM101) . The ability of GSTT1-1 to mediate the mutagenicity of these di- and trihalomethanes and the induction of almost exclusively GC-->AT transitions by these compounds suggest that these halomethanes are activated by similar pathways in RSJ100, possibly through similar reactive intermediates . The implications of these findings are discussed in relation to previous experimental work on the GST-mediated bioactivation of dihalomethanes, which includes the possible formation of GSH intermediates and/or GSH-DNA adducts.

Am J Physiol, 1997 Dec, 273(6 Pt 1), E1052 - 8
Leucine metabolism in TNF-alpha- and endotoxin-treated rats: contribution of hepatic tissue; Holecek M et al.; The effects of tumor necrosis factor-alpha (TNF-alpha; cachectin) and lipopolysaccharide of Salmonella enteritidis (LPS; endotoxin) on leucine metabolism in rats were evaluated in the whole body using intravenous infusion of L-{1-14C}leucine and in isolated perfused liver (IPL) using the single-pass perfusion technique with alpha-keto{1-14C}isocaproate as a tracer for measurement of ketoisocaproic acid (KIC) oxidation, and the recirculation technique for measurement of hepatic amino acid exchanges . The data obtained in TNF-alpha and LPS groups were compared with those obtained in controls . Both TNF-alpha and LPS treatment induced an increase of whole body leucine turnover, oxidation, and clearance . As the result of a higher increase of leucine oxidation than of incorporation into the pool of body proteins, the fractional oxidation of leucine was increased . The fractional rate of protein synthesis increased significantly in the spleen (both in TNF-alpha and LPS rats), in blood plasma, liver, colon, kidneys, gastrocnemius muscle (in LPS rats), and in lungs (TNF-alpha-treated rats), whereas it decreased in the jejunum (LPS rats) . In IPL of TNF-alpha- and LPS-treated rats a decrease of KIC oxidation and higher uptake of branched-chain amino acids (BCAA; valine, leucine, and isoleucine) were observed when compared with control animals . We hypothesize that the negative consequences of increased whole body proteolysis and of increased oxidation of BCAA induced by TNF-alpha and/or LPS are reduced by decreased activity of hepatic branched-chain ketoacid dehydrogenase that can help resupply BCAA to the body.

Mutat Res, 1997 Nov 28, 381(2), 157 - 61
Mutagenicity and polycyclic aromatic hydrocarbon content of fumes from heated cooking oils produced in Taiwan; Chiang TA et al.; According to epidemiologic studies, exposure of women to fumes from cooking oils appears to be an important risk factor for lung cancer . Fume samples from three different commercial cooking oils frequently used in Taiwan were collected and analyzed for mutagenicity in the Salmonella/microsome assay . Polycyclic aromatic hydrocarbons were extracted from the samples and identified by HPLC chromatography . Extracts from three cooking oil fumes were found to be mutagenic in the presence of S9 mix . All samples contained dibenz{a,h}anthracene (DB{a,h}A) and benz{a}anthracene (B{a}A) . Concentration of DB{a,h}A and B{a}A were 1.9 and 2.2 micrograms/m3 in fumes from lard oil, 2.1 and 2.3 micrograms/m3 in soybean oil, 1.8 and 1.3 micrograms/m3 in peanut oil, respectively . Benzo{a}pyrene (B{a}P) was identified in fume samples of soybean and peanut oil, in concentrations of 19.6 and 18.3 micrograms/m3, in this order . These results provide experimental evidence and support the findings of epidemiologic observations, in which women exposed to the emitted fumes of cooking oils are at increased risk of contracting lung cancer.

Mutat Res, 1997 Dec 12, 396(1-2), 45 - 64
Thalidomide: lack of mutagenic activity across phyla and genetic endpoints; Ashby J et al.; The human and rabbit teratogen thalidomide has been tested for mutagenicity in a wide range of assays, ranging from bacterial gene mutation assays conducted in vitro to in vivo cytogenetic assays conducted using rabbits, and including a variety of human-derived tissues . Thalidomide was not mutagenic to 6 strains of Salmonella when tested both in the presence and absence of Aroclor-induced rat liver S9 mix . This inactivity was confirmed in strains TA98 and TA100 using a 1-h pre-incubation assay protocol with the same S9 mix (10% S9), and additionally, in strain TA98 using 3 concentrations of S9 (4%, 10% and 30% S9 in S9 mix) . Thalidomide was not clastogenic either to cultured human lymphocytes (whole blood cultures, minus S9 mix) or to Chinese hamster ovary (CHO) cells treated in vitro . Further, no cytotoxicity was observed in purified human lymphocytes when exposed to thalidomide up to the limit of its solubility in the medium in the presence and absence of liver S9 from Aroclor-induced pregnant rabbit . The CHO assays were conducted without metabolic activation and in the presence of a variety of sources of auxiliary metabolic activation (PB/beta NP-induced rat liver S9 mix, pooled male and female human liver S9 mix, uninduced and Aroclor-induced pregnant rabbit liver S9 mix and foetal rabbit S9 mix) . Thalidomide did not induce micronuclei in isolated human lymphocytes (minus S9 mix) and it was non-mutagenic to mouse lymphoma L5178Y TK+/- cells when tested to the limits of its solubility in the culture medium (+/- S9 mix) . No indication of recombinogenic or clastogenic activity was observed for thalidomide when tested in Drosophila . In addition, it failed to induce chromosome aberrations in grasshopper neuroblasts when tested in the presence and absence of Aroclor-induced rat liver S9 mix . Some unusual chromosome morphologies were observed in the grasshopper cytogenetic preparations indicating a potential of thalidomide to interact with chromosomal proteins . However, this potential was not evident in the human lymphocyte micronucleus assay, and thalidomide was apparently not reactive to the proteins of the mouse skin, as it gave negative results in a mouse local lymph node assay for skin sensitizing agents . Thalidomide was inactive in bone marrow micronucleus assays conducted using males and females from two strains of mice, and female New Zealand white rabbits . It is concluded that thalidomide is neither a mutagen nor an aneugen . This conclusion is discussed within the context of the results of earlier mutagenicity studies, the recent claim that thalidomide may be a heritable germ cell mutagen to humans, and the current interest in thalidomide for the treatment of immune system-related diseases.

Mutat Res, 1997 Nov 27, 394(1-3), 81 - 93
Genotoxicity assessment of suspended particulate matter in the Elbe river: comparison of Salmonella microsome test, arabinose resistance test, and umu-test; Vahl HH et al.; This study evaluates the applicability of three bacterial short-term genotoxicity test systems to aquatic suspended particulate matter of the Elbe river . This material was sampled in sedimentation vessels after deposition periods of one month . It was extracted in a Soxhlet apparatus with toluene and methanol . Aqueous elutriates were prepared additionally . A solid phase method was developed that enables to incubate bacteria in contact with the particulate material . The test battery consists of two mutagenicity assays (the Ames-test and the Ara-test) and an SOS induction assay (the umu-test) . Both mutagenicity assays came to nearly the same assessment of the samples of particulate matter of the Elbe . The quantitative response, however, was higher in the Ara-test . The particulate river material generally induced lower genotoxic potencies in the umu-test than in the mutagenicity assays . This lead to a completely different outcome of the umu-test; 29 out of 35 mutagenic samples were not SOS inducing . No quantitative or rank correlations between the concentrations of anthropogenic contaminants (PAHs, chlorinated hydrocarbons and metals) and the observed effects could be established on a 90% confidence limit . However, there is obvious correspondence between more contaminated regions of the river system and mutagenic effects (Ames- and Ara-test) in the samples from this region, as well as correspondence between low contaminated regions and the absence of mutagenicity . For this reason, the mutagenicity assays appear more favourable to describe the anthropogenic contamination with genotoxins in complex mixtures than the umu-test . The authors recommend the Ara-test for a first genotoxicity screening of complex environmental mixtures . This forward mutagenicity assay is advantageous due to higher effects and lower costs compared to the Ames-test . The development and use of a solid phase version of Ames- and Ara-test revealed the occurrence of a major part of particle-bound mutagens . The hydrophobic nature of these mutagens was also confirmed by the gradually decreasing effects with decreasing lipophilicity of the solvents . The results suggest that the solid phase test and the use of extracts complement each other in detecting mutagens of different lipophilicity . Both versions should be used in order to include a broad variety of compounds.

Mutat Res, 1997 Nov 27, 394(1-3), 45 - 51
Activation of arylamines to mutagenic product(s) by two in vitro plant systems; Chiapella C et al.; Plant activation of three isomers of phenylenediamine o- m- and p-phenylenediamine, has been studied . Two in vitro plant systems have been used: Persea americana S117 with mixed-function oxidase (MFO) and peroxidase activities, and Zea mays S9 which contains only peroxidase activity . As genetic endpoint, the classical Salmonella tester strains . TA98 and TA100, their derivatives with high O-acetyltransferase levels (YG1024 and YG1029, respectively) and TA98/1.8-DNP6, deficient in this enzyme, have been assayed . Of the three isomers studied, only m-PDA was activated to mutagenic product(s) by both plant systems . This activation required the bacterial O-acetyltransferase activity to give frameshift mutagenic product(s), detected in TA98 and YG1024 strains . In all the assays the P americana system was more potent than the Z . mays system in activating m-PDA . A slight increase of the number of YG1029 revertants was detected when m-PDA was activated by P . americana, suggesting that this compound can be also converted into ultimate mutagenic product(s) that induce base-pair substitutions . m-PDA activation by Z . mays was dependent on the peroxidase activity of this system, but the activation produced by P . americana was totally dependent on MFOs, because a total inhibition of the mutagenic response was found when these activities were inhibited . In addition, the P . americana system was more potent in generating proximal mutagenic forms from m-PDA than S9 from non-induced rat liver, although S9 from Aroclor 1254-induced Sprague-Dawley male rats was the most potent system in the m-PDA activation . These results indicate that the P . americana system can be useful in determining the role of mixed-function oxidases in plant activation of xenobiotics.

Mil Med, 1997 Dec, 162(12), 783 - 7
Salmonella outbreak in an American child development center in Germany; Newcomb S et al.; In July 1993, an outbreak of Salmonella occurred in a U.S . Army child care center in Heidelberg, Germany . Sixteen children and 4 staff members had confirmed positive cultures; the center had an average census of 135 children during the time of the outbreak . Rectal swabs were done on all the children in rooms with symptomatic children or staff or in rooms with confirmed cases . A total of 246 rectal swabs was done initially, with 216 representing paired specimens . A case was defined as a staff member, child, or family member of an ill staff member or child who attended the center with diarrhea or abdominal pain with at least one of the following symptoms: diarrhea, fever, nausea, loss of appetite, abdominal pain, vomiting, or lethargy . The attack rate for the children was 40 of 86 (47%), and the attack rate for staff was 15 of 47 (32%) . No associations were found when looking at the attack rates in each of the 10 rooms in the center . Complete environmental investigation revealed that the cook was preparing food 1 day before it was served . In addition, he was running the dishwasher without a sufficient amount of soap . Although food was not available for testing, the source of the Salmonella outbreak appears to be uncooked or inadequately cooked and prepared food with some person-to-person transmission.

Am J Trop Med Hyg, 1997 Dec, 57(6), 656 - 9
Longevity of antibody responses to a Salmonella typhi-specific outer membrane protein: interpretation of a dot enzyme immunosorbent assay in an area of high typhoid fever endemicity; Choo KE et al.; The objective of this study was to investigate the longevity of positive dot enzyme immunosorbent assay (dot EIA) results for IgM and IgG to a Salmonella typhi outer membrane protein in Malaysian children with enteric fever . The patients were children one month to 12 years of age with clinical evidence of typhoid fever, positive blood or stool cultures for S . typhi, and/or a positive Widal test result who were admitted over a two-year period to General Hospital (Kota Bharu, Malaysia) . These patients received standard inpatient treatment for enteric fever including chloramphenicol therapy for 14 days . Dot EIA tests were performed as part of clinical and laboratory assessments on admission, at two weeks, and then at 3, 6, 9, 12, 15, 18, and 21 months postdischarge . Assessment of the longevity of positive dot EIA IgM and IgG titers was done by Kaplan-Meier analysis . In 94 evaluable patients, 28% were dot EIA IgM positive but IgG negative on admission, 50% were both IgM and IgG positive, and 22% were IgM negative and IgG positive . Mean persistence of IgM dot EIA positivity was 2.6 months (95% confidence interval = 2.0-3.1 months) and that of IgG was 5.4 months (4.5-6.3 months) . There were no significant differences between the three subgroups . Thus, positive IgM and IgG results determined by dot EIA within four and seven months, respectively, following documented or suspected enteric fever in a child from an endemic area should be interpreted with caution . In other clinical situations, the dot EIA remains a rapid and reliable aid to diagnosis.

Gastroenterology, 1998 Jan, 114(1), 93 - 102
Bacterial induction of inducible nitric oxide synthase in cultured human intestinal epithelial cells; Salzman AL et al.; BACKGROUND & AIMS: Enterocytes play a major role in the mucosa as a source of proinflammatory cytokines and cytotoxins . We tested the hypothesis that bacteria induce expression of the inducible nitric oxide synthase (iNOS) in cultured human enterocytes . METHODS: DLD-1 and Caco-2BBe cell monolayers exposed to Salmonella dublin were analyzed for iNOS up-regulation and nitric oxide production (NOx) in the presence of various proinflammatory cytokines . RESULTS: S . dublin augmented NOx in interferon gamma (IFN-gamma)-primed cells but had no independent effect on iNOS expression . S . dublin-induced NOx was not mediated by endotoxin and was augmented by an enteroinvasive phenotype . In DLD-1 cells, S . dublin-mediated NOx was blocked by inhibitors of nuclear factor kappa B (NF-kappa B) and tyrosine kinase activation and was steroid resistant . Cis-acting elements in the human iNOS promoter responsive to endotoxin and S . dublin stimulation of IFN-gamma-treated DLD-1 cells were identified between 10.9 and 8.7 kilobases upstream of the transcription initiation site . CONCLUSIONS: S . dublin alters the regulation of iNOS messenger RNA in IFN-gamma-treated intestinal epithelial cells via a steroid-resistant pathway involving NF-kappa B and tyrosine kinase activity . Because bacterial interaction with cytokine-primed epithelial cells induces the synthesis of NO, an endogenous antimicrobial agent, these findings may have implications for the regulation of mucosal immunity.

Rev Invest Clin, 1997 Sep-Oct, 49(5), 349 - 53
Salmonella gastroenteritis outbreak among workers from a tertiary care hospital in Mexico City; Molina-Gamboa JD et al.; OBJECTIVE: To describe an outbreak of Salmonella gastroenteritis among employees of the National Institute of Nutrition (INNSZ) of Mexico City during July, 1994 . METHODS: Employees who developed diarrhea or fever associated with gastrointestinal symptoms starting on July 14th were included for study as well as 50 healthy controls . A questionnaire was applied to all, and they also provided a stool sample, along with other 80 asymptomatic people (included the kitchen workers) in whom only stool culture was done . RESULTS: Ninety-seven employees that ate regularly at the Hospital's cafeteria were affected by the outbreak, and 67 of them (69%) could be evaluated . Most of them were nurses (34%), and handymen (27%) . Most common symptoms were abdominal pain (97%), diarrhea (95%), nausea (91%), and fever (89%) . Cultures from suspicious food items were all negative, but stool cultures from 10/70 cases were positive for Salmonella enteritidis vs . 0/133 in the controls . The ten S . enteritidis isolates resulted identical either by serotyping and by rapid amplified polymorphic DNA (RAPD) analysis . Cultures from all kitchen employees were negative for S . enteritidis . Breakfast meal on July 14th was associated with the development of gastroenteritis (61/67 cases vs 26/50 controls, p < 0.001), and particularly with an egg-covered meat plate (61/62 vs 13/26 controls, p < 0.0001) . CONCLUSIONS: This outbreak was probably caused by eggs contaminated with Salmonella, since no one of the kitchen personnel was found to be an asymptomatic carrier, and the implicated recipe allows for inappropriate cooking . Recommendations to improve cooking procedures must be added to the usual regulations to diminish the frequency of foodborne disease outbreaks in hospitals.

Gene, 1997 Nov 20, 202(1-2), 147 - 9
Viral spread within ageing bacterial populations; Ramirez E et al.; The viral spread within isolated host populations has been studied throughout the growth of P22-infected Salmonella cell colonies . By using an integration mutant of this bacteriophage, horizontal and vertical transmission have been analyzed independently . The data obtained show that both strategies are not simultaneous but consecutive during the colony development . Lytic cycles are tightly repressed during the exponential cell growth but stimulated in independent colonies with remarkable synchrony when the cell division rate decreases . The coincidence of the viral outburst and the decay of bacterial replicative fitness is a new example of the extreme viral competence in exploiting the host cells as dissemination vehicles for viral genomes.

Can Vet J, 1997 Dec, 38(12), 780 - 1
Outbreak of Salmonella give in the province of Quebec; Higgins R et al.; Salmonellosis due to Salmonella Give involving cows, a goat, and an ostrich over a 6-month period was investigated . Cases were found in 4 different regions . Antimicrobial susceptibility patterns, phagetyping, and pulsed-field gel electrophoresis analyses confirmed that all isolates belonged to the same clone . A common source of infection was suspected.

Mol Microbiol, 1997 Dec, 26(5), 939 - 50
Mechanism of bacteriophage SfII-mediated serotype conversion in Shigella flexneri; Mavris M et al.; We have isolated the lysogenic bacteriophage SfII, which mediates glucosylation of Shigella flexneri O-antigen, resulting in expression of the type II antigen . SfII belongs to group A of the Bradley classification and has a genome size of 42.3kb . DNA sequencing of a 4 kb BamHI subclone identified four open reading frames (ORFs), of which only two were found to be necessary for serotype conversion . These genes were named bgt, which encodes a putative bactoprenol glucosyl transferase, and gtrII, encoding the putative type II antigen determining glucosyl transferase . These genes are adjacent to the integrase gene (int) and attachment site (attP), which are highly homologous to those of Salmonella bacteriophage P22 . Another ORF encoded a highly hydrophobic protein of 120 amino acids with homologues in Escherichia coli, Salmonella bacteriophage P22 and S . flexneri . Previous studies identified gtrX, the glucosyl transferase gene, of bacteriophage SfX, which also glucosylates the O-antigen specifically . We determined that gtrX-mediated expression of the group 7,8 antigen also requires bgt . This allowed us to identify gtrII as being the serotype antigen II determining glucosyl transferase . Southern hybridization and polymerase chain reaction (PCR) analyses indicated that bgt homologues exist in the genomes of all S . flexneri serotypes and in E . coli K-12, whereas gtrII was only detected in strains of serotype 2 . Transposon TnphoA-derived chromosomal mutations of bgt and gtrII in S . flexneri serotype 2a were isolated and characterized . {35S}-methionine labelling and the use of a T7 RNA polymerase expression system identified a protein of 34kDa corresponding to Bgt . However, GtrII, which has a predicted molecular weight of 55 kDa, was not detected . We propose that the function of Bgt is to transfer the glucose residues from the UDP-glucose onto bactoprenol and GtrII then transfers the glucose onto the O-antigen repeat unit at the rhamnose III position . The chromosomal organization of these serotype-converting genes, when compared with their homologues in E . coli K-12 chromosome and the P22 bacteriophage genome, were very similar . This suggests that the regions encode similar functions in these organisms and have a similar evolutionary origin.

Mol Microbiol, 1997 Dec, 26(5), 845 - 51
RfaH and the ops element, components of a novel system controlling bacterial transcription elongation; Bailey MJ et al.; The RfaH protein controls the transcription of a specialized group of Escherichia coli and Salmonella operons that direct the synthesis, assembly and export of the lipopolysaccharide core, exopolysaccharide, F conjugation pilus and haemolysin toxin . RfaH is a specific regulator of transcript elongation; its loss increases transcription polarity in these operons without affecting initiation from the operon promoters . The operons of the RfaH-dependent regulon contain a short conserved 5' sequence, the ops element, deletion of which increases operon polarity to an extent similar to that caused by loss of RfaH . The ops element is also present upstream of polysaccharide gene clusters of Shigella flexneri, Yersinia enterocolitica, Vibrio cholerae and Klebsiella pneumoniae and the RP4 fertility operon of Pseudomonas aeruginosa, suggesting that this is a widely spread control system . The mechanistic coupling of RfaH and the ops element has been demonstrated in vitro and in vivo, and we suggest that the ops element recruits RfaH and potentially other factors to the RNA polymerase complex, modifying the complex to increase its processivity and allowing transcription to proceed over long distances.

J Biol Chem, 1997 Dec 5, 272(49), 30703 - 8
A newly identified horseshoe crab lectin with binding specificity to O-antigen of bacterial lipopolysaccharides; Saito T et al.; We identified a novel horseshoe crab hemocyte-derived lectin, which we named tachylectin-4 . It has more potent hemagglutinating activity against human A-type erythrocytes than a previously identified hemocyte lectin with an affinity to N-acetylglucosamine, tachylectin-2 . The purified tachylectin-4 is an oligomeric glycoprotein of 470 kDa, composed of subunits of 30 and 31.5 kDa . Ca2+ at 10 mM enhanced the hemagglutinating activity 4-fold, and the activity was inhibited by EDTA and o-phenanthroline . L-Fucose and N-acetylneuraminic acid at 100 mM completely inhibited the activity of tachylectin-4 . The activity was also inhibited more strongly by bacterial S-type lipopolysaccharides (LPS) but not by R-type LPS lacking O-antigen . The most effective S-type LPS was from Escherichia coli O111:B4, and the minimum concentration required for inhibiting agglutination against human A-type erythrocytes (0.1 microg/ml) was 160-fold lower than those of S-type LPS from Salmonella minnesota . Therefore, colitose (3-deoxy-L-fucose), a unique sugar present in the O-antigen of E . coli O111:B4 with structural similarity to L-fucose, is the most probable candidate for a specific ligand of tachylectin-4 . A cDNA coding for tachylectin-4 was isolated from a hemocyte cDNA library . The open reading frame of the 1344-base pair cDNA coded for the mature protein with 232 amino acids . There is no significant sequence similarity to any other known LPS-binding lectins, whereas tachylectin-4 is homologous to the NH2-terminal domain with unknown functions of Xenopus laevis pentraxin 1.

Clin Diagn Lab Immunol, 1997 Nov, 4(6), 774 - 7
Salmonella infection increases porcine antibacterial peptide concentrations in serum; Zhang G et al.; PR-39 is a multifunctional neutrophil peptide involved in host defense and inflammation . To investigate the involvement of PR-39 in a Salmonella choleraesuis infection, a PR-39 enzyme immunoassay was developed . The concentrations of PR-39 in serum were 13.6 +/- 1.9 ng/ml before challenge and increased (P < 0.01) threefold by 10 to 14 days postinfection . Peripheral blood neutrophil counts paralleled the changes in the concentrations of PR-39 in serum, both returned to basal values by 4 weeks postinfection . These findings suggest that the concentrations of serum PR-39 reflect the involvement of this antibacterial peptide in the host's response to an S . choleraesuis infection.

Harefuah, 1997 Oct 2, 133(7-8), 255 - 64, 336
{Epidemiological characteristics of outbreaks of diarrhea and food poisoning in the Israel Defense Forces in the years 1978-1995}; Grotto I et al.; Acute infectious diseases of the gastrointestinal tract and food poisoning are problems of great importance in the Israel Defense Forces (IDF) . They involve individual and epidemic morbidity, with impairment of health of individual soldiers and in the activities of units . Outbreaks of gastrointestinal infectious diseases must be reported to the IDF army health branch, which conducts epidemiological investigation . This study is based on data from yearly epidemiological reports for 1978-1989, and from a computerized database for the years 1990-1995 . The incidence of outbreaks is characterized by an unstable trend . It was highest at the end of the 80's (68.3 per 100,000 soldiers on active duty) and lowest for the last 2 years (1994-1995, 36.3 per 100,000) . The incidence of soldiers involved in food-borne outbreaks has been more stable, constantly declining during the course of the years . There was marked seasonality with a peak in the summer months . Sporadic morbidity was constant in 1990-1995, with a yearly attack rate of 60% in soldiers on active duty . Shigella strains were the leading cause of outbreaks until 1993, while in 1994-1995 their proportion decreased, with an increase in the proportion of Salmonella strains . As to Staphylococcus aureus, its role in causing food poisoning has been characterized by marked changes . Shigella sonnei replaced Shigella flexneri as the leading strain . 73.3% of outbreaks were small, with fewer than 40 soldiers involved, while 5.4% of outbreaks affected more than 100 soldiers . Outbreaks in which a bacterial agent was identified or which occurred in new-recruit bases were larger than those in which a bacterial agent was not identified, or which occurred in active field unit bases . In conclusion, the rates of infectious disease of the gastrointestinal tract are still high, although there has been a marked decrease since 1994 . The incidence of outbreaks has also decreased, as well as the role of Shigella as a leading causative agent.

FEMS Microbiol Lett, 1997 Dec 1, 157(1), 177 - 81
Characterisation of integrons and antibiotic resistance genes in Danish multiresistant Salmonella enterica Typhimurium DT104; Sandvang D et al.; The presence and genetic content of integrons was investigated in eight Salmonella enterica Typhimurium DT104 isolates from different pig herds in Denmark . Two different integrons were identified using PCR and sequencing . Each of the integrons carried a single resistance cassette in addition to the sul1 and qacE delta 1 genes characteristic of integrons . The first integron encoded the ant (3")-Ia gene that specified resistance to spectinomycin and streptomycin . The second contained the pse-1 beta-lactamase gene . All the multiresistant strains contained both integrons . The presence of these two integrons did not account for the total phenotypic resistance of all the isolates and does not exclude the presence of other mobile DNA elements.

Vet J, 1997 Nov, 154(3), 227 - 32
Cervico-thoracic vertebral osteomyelitis in 14 calves; Healy AM et al.; Fourteen cases of cervico-thoracic (C-T) vertebral osteomyelitis in calves were investigated over a 6 year period . The onset of clinical signs was between 2 and 9 weeks of age . There was no breed or sex predisposition . The clinical history prior to referral extended from 5 days to 8 weeks (mean 20 days) . The most common clinical presentation was difficulty in rising with a tendency to knuckle or kneel on the forelimbs which displayed hypotonia and hyporeflexia . In over half the cases pain could be elicited on manipulation of the neck . The lesion in all cases involved one or more of the vertebrae from C6 to T1 . The diagnosis was confirmed by radiology and/or at post mortem . Four animals were discharged after treatment, 10 animals were humanely destroyed . Salmonella dublin was isolated from the vertebral lesion in eight of the 10 calves at post mortem.

Anticancer Res, 1997 Sep-Oct, 17(5A), 3537 - 43
Drug resistance reversal, anti-mutagenicity and antiretroviral effect of phthalimido- and chloroethyl-phenothiazines; Motohashi N et al.; The effect of substituted phenothiazines was studied in three different systems; bacteria and cancer cells and reverse transcriptase enzyme of Moloney leukemia virus . F'lac and hemolysin plasmids were eliminated by some substituted phenothiazines from E . coli at a very low frequency . The same phenothiazine derivatives also were synergistic with tetracycline in bacteria and shown antimutagenic effect in Ames test . No mutagenic effects were observed in TA 98 strain of Salmonella typhimunium . Chloroethyl-substituted phenothiazines showed antimutagenicity equivalent to the parent compounds; however, phthalimido-substituted phenothiazines had higher antimutagenicity of 50% . P-glycoprotein responsible for multidrug resistance was also inhibited in tumor cells . The accumulation of the fluorescent rhodamine 123 in the phenothiazine treated multi-drug resistant tumor cells was measured by flow cytometry . Some of the substituted phenothiazines were effective P-glycoprotein blockers, while some compounds had moderate activity, but others were without effect as compared to 5 microM verapamil . On the basis of computer analysis there are some correlations between the biological activities and the dipole moments, and entropy of the studied molecules . Our results suggest that the inhibition of Hly+ plasmid replication and P-glycoprotein function may depend partly on similar electronic properties of the studied phenothiazine derivatives . The activity of Moloney leukemia virus reverse transcriptase was inhibited by the substituted phenothiazines, however, no basic differences were found in the activities of phthalimido- and chloroethyl substituted phenothiazines.

J Am Vet Med Assoc, 1997 Dec 15, 211(12), 1554 - 7
Outbreak of Salmonella infantis infection in a large animal veterinary teaching hospital; Tillotson K et al.; During the past 11 years, there have been numerous reports of outbreaks of salmonellosis involving horses in veterinary teaching hospitals . Some of these outbreaks have been associated with Salmonella serotypes not commonly associated with infection of horses . Salmonella infantis is among the more common Salmonella serotypes isolated from human beings, and is an important pathogen in the broiler chicken industry . However, it was not commonly isolated from horses or cattle on a national basis between 1993 and 1995 . In this report, we describe an outbreak of S infantis infection among large animals, primarily horses, in a veterinary teaching hospital and the control measures that were implemented . Factors that appeared to be key in control of this outbreak in this hospital included providing biosecurity training sessions for hospital personnel, adopting a standard operating procedure manual for biosecurity procedures, installing additional handwashing sinks throughout the facility, painting the interior of the facility with a nontoxic readily cleanable paint, replacing the dirt flooring in 4 stalls with concrete flooring, and removing noncleanable surfaces such as rubber stall mats, wooden hay storage bins, and open grain bins . Our experience with this outbreak suggests that although it is virtually impossible to eliminate Salmonella organisms from the environment, minimizing contamination is possible . Prevention of nosocomial infection must be approached in a multifaceted manner and care must be taken to search out covert sources of contamination, especially if standard intervention procedures do not prevent spread of the disease.

Bull Soc Pathol Exot, 1997, 90(3), 160 - 1
{Bacterial diversity during the cholera epidemic in Dakar, Senegal (1995-1996)}; Sow AI et al.; Vibrio cholerae O:1, serotype Ogawa and biotype El Tor (76.1%) was responsible of the outbreak of cholera in Dakar, Senegal (1995-1996) . However, other bacteria were isolated, particularly Vibrio cholerae non O:1/non O:139, Vibrio fluvialis, Vibrio alginolyticus . Vibrio parahaemolyticus, Salmonella sp.p, Shigella sp.p (23.9%) . The Vibrio cholerae O:1 strains are multiresistant to sulfonamide, cotrimoxazole and chloramphenicol . 97% were also resistant to O/129 compound . Fluoroquinolone and 3rd generation cephalosporins were the more efficient antibiotics (100%).

Zentralbl Hyg Umweltmed, 1996 May, 198(5), 429 - 42
{Mutagenicity, genotoxicity and cogenotoxicity of environmentally relevant nitro musk compounds}; Mersch-Sundermann V et al.; In the present study a new in vivo/in vitro animal model was used to study the ability and potency of musk ketone and musk xylene to induce liver specific oxygenases (in vivo) which are necessary of toxify different premutagens, pregenotoxicants and/or precarcinogens to the ultimate DNA damaging agents . Therefore, rats were pretreated with 10, 20 and 40 mg/d nitro musk (NMV) for 5 days by intraperitoneal (i.p.) injection . Then the postmitochondrial fractions of the hepatocytes (S9M) were used to examine the metabolic potency for toxification of the pregenotoxicants benzo{a}pyrene (B{a}P) and 2-aminoanthracene (2-AA) using the SOS chromotest (in vitro) . Furthermore, musk xylene, musk ketone, musk ambrette, musk moskene and musk tibetene were examined for their mutagenicity in the Salmonella/microsome assay using S . typhimurium TA97, TA98, TA100 and TA102 and for their genotoxicity in the SOS chromotest using Escherichia coli PQ37 (sfiA::lacZ) in the presence and absence of an exogenous metabolizing system (S9 of PCB induced rats = S9A) . Both musk ketone and musk xylene were identified als inducers of toxifying enzymes (oxygenases) in rat liver . Using the in vivo/in vitro model these isoenzyme inductions led to a metabolisation (toxification) of the pregenotoxicants benzo{a}pyrene (B{a}P) and/or 2-aminoanthracene (2-AA) (cogenotoxicity) . Using S9M fractions of rats which were i.p.-pretreated with 5 x 40 mg musk ketone the induction factor in the SOS chromotest was IFmax = 4.0 by using 1 nmole B{a}P and IFmax > 4.0 by using 20 nmole 2-AA . Thus, musk ketone seems to be a Cytochrome P450 1A1 and 1A2 isoenzyme inducer in mammals . On the other hand the S9M fractions of musk xylene pretreated rats showed only a toxification of 2-AA (IFmax = 3.0) . Therefore, a synergistic effect of enzyme inducers, i.e . musk xylene and musk ketone, and pregenotoxicants, i.e . B{a}P and 2-AA, regarding DNS damaging effects was identified . Musk ambrette showed high mutagenicity in S . typhimurium TA100 (500 His(-)-revertants per mumole, +S9A) . Unexpectedly, these DNA damaging effects were not caused by bacterial nitroreductases but by rat S9A metabolisation (!) . SOS inducing DNA damages in E . coli PQ37 were not produced (IFmax < 1.5) . On the basis of the results presented and under consideration of the concentrations of NMV, other cogenotoxicants and pregenotoxicants such as B{a}P and 2-AA in environmental samples and human tissues, a genotoxic risk for humans has to be assumed.

Genetics, 1997 Dec, 147(4), 1509 - 20
Size and sequence polymorphism in the isocitrate dehydrogenase kinase/phosphatase gene (aceK) and flanking regions in Salmonella enterica and Escherichia coli; Nelson K et al.; The sequence of aceK, which codes for the regulatory catalytic enzyme isocitrate dehydrogenase kinase/phosphatase (IDH K/P), and sequences of the 5' flanking region and part or all of the 3' flanking region were determined for 32 strains of Salmonella enterica and Escherichia coli . In E . coli, the aceK gene was 1734 bp long in 13 strains, but in three strains it was 12 bp shorter and the stop codon was TAA rather than TGA . Strains with the shorter aceK lacked an open reading frame (f728) downstream between aceK and iclR that was present, in variable length, in the other strains . Among the 72 ECOR strains, the truncated aceK gene was present in all isolates of the B2 group and half of those of the D group . Other variant conditions included the presence of IS1 elements in two strains and large deletions in two strains . The aceK-aceA intergenic region varied in length from 48 to 280 bp in E . coli, depending largely on the number of repetitive extragenic palindromic (REP) sequences present . Among the ECOR strains, the number of REP elements showed a high degree of phylogenetic association, and sequencing of the region in the ECOR strains permitted partial reconstruction of its evolutionary history . In S . entica, the normal length of aceK was 1752 bp, but three other length variants, ranging from 1746 to 1785 bp, were represented in five of the 16 strains examined . The flanking intergenic regions showed relatively minor variation in length and sequence . The occurrence of several nonrandom patterns of distribution of polymorphic synonymous nucleotide sites indicated that intragenic recombination of horizontally exchanged DNA has contributed to the generation of allelic diversity at the aceK locus in both species.

Clin Exp Immunol, 1997 Dec, 110(3), 454 - 63
Antigen-presenting cells (APC) of mice with chronic graft-versus-host disease (GVHD) cause excessive activation-induced death of T helper cells; Haridas V et al.; Both experimental and clinical forms of chronic GVHD have unique immunological features . The affected animals/individuals suffer from autoimmune disorders such as systemic lupus erythematosus (SLE), and yet they are unable to mount a self MHC-restricted T cell response to foreign antigens . Pathogenesis of the latter phenomenon was investigated in an experimental model of chronic GVHD . Chronic GVHD was induced in 8-10-week-old (B6xC3H)F1 mice by tail vein injection of 5 x 10(7) spleen cells of C3H parental strain . The recipients, when tested 3 months later, were unable to mount a T helper (Th) cell response to a randomly selected immunogen, a vaccine of l0(8) killed Mycobacterium vaccae . The animals showed evidence of generalized lymphoid hyperplasia, as indicated by GVH index >1.34, and also revealed autoantibodies against erythrocytes and dsDNA, indicating establishment of chronic GVHD . However, mice with chronic GVHD of only 3 weeks duration were able to mount the Th cell response to M . vaccae . Three consecutive immunizations of these mice at 1-week intervals, with the same immunogen, resulted in the mice becoming non-responsive to the antigen . All the three responses tested, namely the DTH, lymphoproliferation and the antibody responses, were adversely affected . The non-responsiveness induced was antigen-specific . Mice receiving two immunizations with M . vaccae responded normally to Salmonella enteritidis . Pulse treatment with cyclosporin A 0.5 mg/mouse by the i.p . route, on days 0, 1, 2, 3 and 4 at the time of immunization with M . vaccae on day 1, prevented emergence of non-responsiveness . Based on this evidence, it was concluded that repeated activation of T cells of mice with chronic GVHD induces non-responsiveness . Extent of clonal loss due to activation-induced cell death (AICD) caused by i.p . injection with a superantigen Staphylococcal enterotoxin B (SEB) was investigated in F1 mice with chronic GVHD . I.p . injection of 25 microg/mouse of SEB induced loss of SEB responding clones in both normal F1 mice and those having chronic GVHD; however, the extent of loss was much greater in the latter . In vitro antigen-specific proliferation of primed splenic T cells of normal F1 mice was observed to be quite poor when antigen was presented by APC of mice with chronic GVHD of 3 weeks duration . Proliferation profiles of T cells of normal F1 mice, in response to stimulation with concanavalin A (Con A) or SEB, were studied, using as APC irradiated spleen cells of normal F1 mice or of F1 mice with chronic GVHD of 3 weeks duration . With Con A and APC of normal F1 mice, peak proliferation was observed at 48 h, which remained at the same level up to 72 h and declined thereafter, possibly due to AICD . With SEB and the normal APC, proliferation progressively peaked at 72 h and declined thereafter . With APC of mice with chronic GVHD, the 48 h proliferative responses of both Con A and SEB were comparable to those caused by APC of normal F1 mice; however, thereafter the responses declined steeply, suggesting greater AICD . Based on these results, it was concluded that APC of mice with chronic GVHD are functionally altered to induce greater AICD.

New Microbiol, 1997 Oct, 20(4), 365 - 9
The survival of Salmonella anatum, pseudorabies virus and porcine reproductive and respiratory syndrome virus in swine slurry; Ajariyakhajorn C et al.; The survival of Salmonella anatum, pseudorabies virus (PRV), and porcine reproductive and respiratory syndrome virus (PRRSV) in swine slurry was studied at different temperature (4 degrees C, 25 degrees C, and 37 degrees C) and pH (4.0, 7.0, and 10.0) conditions . The longest survival of S . anatum (56 days) was observed at 4 degrees C and pH 7.0 . The pseudorabies and the PRRS viruses also survived the longest at 4 degrees C and pH 7.0 but were inactivated within 8 and 14 days, respectively.

Mutat Res, 1997 Oct, 387(2), 89 - 96
Review of the genotoxicity of 2-butoxyethanol; Elliott BM et al.; The available data on the genotoxicity of 2-butoxyethanol have been reviewed . 2-Butoxyethanol has been examined for genotoxic activity in a range of in vitro and in vivo assays, including the mouse bone marrow micronucleus assay . The in vitro assays used range from well validated and generally accepted assays such as the Salmonella/microsome and in vitro cytogenetic assay, through to less well validated assays such as assessment of the inhibition of metabolic cooperation in V79 cells . The levels of experimental details and data reporting vary across the studies with some papers presenting only limited information . Taking the above factors into consideration, the available data indicate that 2-butoxyethanol has no significant genotoxic activity . This conclusion is also consistent with the chemical structure of 2-butoxyethanol, which is not alerting for likely genotoxic activity . These collected considerations indicate that 2-butoxyethanol is unlikely to be a genotoxic carcinogen to rodents, a prediction that supplements seventeen published predictions of the outcome of the ongoing NTP rodent carcinogenicity bioassays.

J Antimicrob Chemother, 1997 Oct, 40(4), 567 - 72
Evaluation of protection by two endotoxin-neutralizing IgM monoclonal antibodies in different peritonitis models; Hustinx WN et al.; Two anti-core glycolipid (CGL) IgM monoclonal antibodies (mAbs 8-2 and 26-20), previously shown to display cross-reactivity with heterologous lipopolysaccharide (LPS) in vitro and to provide cross-protectivity against endotoxin challenge in vivo, were evaluated for their potential to protect mice against death from peritonitis caused by heterologous bacterial challenge . Without concurrent antibiotic treatment neither antibody was protective . Compared with a control mAb, prophylactic treatment with mAb 8-2 significantly increased the survival of gentamicin-treated mice challenged with the rough strain Salmonella minnesota Re595 . Both mAb 8-2 and a control mAb, in combination with a suboptimal dose of ceftazidime, increased survival following challenge with the clinical isolate Escherichia coli O7:K1 . In a model of mucin-enhanced peritonitis, neither mAb was protective against challenge with inocula of E . coli O7:K1, ranging from 10(2) to 10(4) bacteria . We conclude that protection of mice by anti-CGL mAb 8-2 against heterologous challenge is vitally dependent on concurrent treatment with antibiotics and that protection may not be attributable to the anti-CGL specificity of these antibodies.

Heart, 1997 Oct, 78(4), 416 - 8
Cardiac conduction abnormalities preceding transoesophageal echocardiographic evidence of perivalvar extension of infection in a case of Salmonella prosthetic valve endocarditis; Miyamoto MI et al.; A 59 year old African-American man developed complete heart block in association with Salmonella enteritidis prosthetic valve endocarditis . Severe cardiac conduction abnormalities signalled the presence of perivalvar extension of infection before development of evidence of abscess by transoesophageal echocardiography . Cardiac conduction temporarily returned after debridement and aortic homograft placement . This case emphasises the value of electrocardiographic monitoring in the detection of perivalvar extension of infection complicating infective endocarditis, even in the era of sophisticated imaging modalities.

J Dairy Sci, 1997 Nov, 80(11), 3064 - 7
Animal by-products contaminated with Salmonella in the diets of lactating dairy cows; Bender JB et al.; As part of a total mixed ration, two rumen-fistulated dairy cows were fed meat and bone meal that had been artificially contaminated with Salmonella spp . Samples from the rumen, feces, and milk were taken 3 d/wk and cultured for salmonella . Rectal temperatures and rumen pH were also measured at the time of sample collection . Over the 2-mo study, salmonella were intermittently recovered from rumen contents, from feces, and from necropsy specimens of rumen contents, cecal contents, and mesenteric lymph nodes . No excretion of salmonella in milk was detected . An elevated rumen pH was associated with increased isolation of salmonella . No clinical illness was observed for either cow . Meat and bone meal that has been contaminated with low concentrations of salmonella is unlikely to result in clinical illness in healthy adult lactating cows . However, dairy producers should continue to be concerned about feed biosecurity and water contamination of animal by-products to prevent and control contamination by salmonella.

Biol Trace Elem Res, 1997 Oct-Nov, 60(1-2), 13 - 26
Lead disrupts eicosanoid metabolism, macrophage function, and disease resistance in birds; Knowles SO et al.; Lead (Pb) affects elements of humoral and cell-mediated immunity, and diminishes host resistance to infectious disease . Evidence is presented supporting a hypothesis of Pb-induced immunosuppression stemming from altered fatty acid metabolism, and mediated by eicosanoids and macrophages (MO) . Chronic Pb exposure increases the proportion of arachidonate (ArA) among fatty acids in lipid from avian tissues, and this change provides precursors for eicosanoids, the oxygenated derivatives of ArA that mediate MO acute inflammatory response . In the current study, we showed that the concentration of ArA in phospholipids of MO elicited from turkey poults fed 100 ppm dietary Pb acetate was twice that of controls . In vitro production of eicosanoids by these MO was substantially increased, and this effect was most pronounced following lipopolysaccharide stimulation: prostaglandin F2 alpha was increased 11-fold, thromboxane B2 increased threefold, and prostaglandin E2 increased by 1.5 times . In vitro phagocytic potential of these MO was suppressed, such that the percentage of MO engulfing sheep red blood cell (RBC) targets was reduced to half that of control MO . In vivo susceptibility of Pb-treated and control birds to Gram-negative bacteria challenge was also evaluated . The morbidity of chicks inoculated with Salmonella gallinarum and fed either control or 200 ppm Pb acetate-supplemented diets was similar, except early in the course of the disease when mortality among Pb-treated birds was marginally greater . In these studies, effects of Pb that could influence immunological homeostasis were demonstrated for MO metabolism of ArA, for production of eicosanoids, and for phagocytosis . There was also the suggestion that these in vitro indices of immune function are related to in vivo disease resistance.

Res Microbiol, 1997 Jan, 148(1), 21 - 6
Molecular characterization of the Salmonella typhi StpA protein that is related to both Yersinia YopE cytotoxin and YopH tyrosine phosphatase; Arricau N et al.; Analysis of the nucleotide sequence of a 4-kb DNA fragment located between the sip and iag loci on Salmonella typhi chromosome revealed three open reading frames, termed sipF, ctpA and stpA . The 82-amino-acid (aa) sipF product showed extensive similarity to the lacP protein from S . typhimurium . The StpA protein (535 aa) exhibited significant similarity to both Yersinia enterocolitica YopE cytotoxin and YopH tyrosine phosphatase . The CtpA polypeptide (130 aa) might be the molecular chaperone of the StpA protein.

Microbiol Immunol, 1997, 41(10), 791 - 4
Amplification of rfbE and fliC genes by polymerase chain reaction for identification and detection of Salmonella serovar Enteritidis, Dublin and Gallinarum-Pullorum; Itoh Y et al.; Polymerase chain reaction (PCR) primers for O9 antigen (rfbE) and phase 1 flagellin antigen (fliC) were designed for the rapid identification and detection of Salmonella serovar Enteritidis and Dublin . The rfbE primer pairs selectively amplified the rfbE region of group O9 Salmonella serovars . The fliC primer pairs amplified the DNAs of g,m and g,p-type flagellar antigen; Salmonella serovar Enteritidis, Dublin, and Essen . However, DNA from flagellar-negative Salmonella serovar Gallinarum-Pullorum was also amplified . The sensitivity of PCR primer pairs was 10(4) CFU/assay by boiled DNA preparation and 10(2) CFU/assay by proteinase K-treated DNA preparation.

Mutat Res, 1997 Nov 19, 381(1), 41 - 7
Nitroreductase independent mutagenicity of 1-halogenated-2,4-dinitrobenzenes; Gupta RL et al.; The 1-halogen substituted 2,4-dinitrobenzenes have been found to be mutagenic in Salmonella TA98 with an activity order of 1-fluoro > 1-chloro > 1-bromo > 1-iodo . This specific activity was not lowered in the nitroreductase deficient strain TA98NR and O-acetyltransferase deficient strain TA98/1,8-DNP6, indicating that the mutagenicity of these compounds is not dependent upon -NO2 reduction to -NHOH and its subsequent esterification . The activity was, rather, higher in the former and remained almost equal in the latter strain compared to TA98, suggesting these compounds to react directly with bacterial DNA . Further, the reaction of these halodinitrobenzenes with methionine, at physiological pH, resulting in the formation of 1-S-methyldinitrobenzene showed that these compounds have the ability to attack DNA directly through nucleophilic substitution of the halogen atom and the role of the bacterial nitroreductases for production of mutagenic lesions was not considered . It was, further, proposed that these compounds interact with DNA through SNAr mechanism instead of SN2 cited in literature.

J Med Microbiol, 1997 Dec, 46(12), 1039 - 42
Low sensitivity of counter-current immuno-electrophoresis for serodiagnosis of typhoid fever; Sharma M et al.; Counter-current immuno-electrophoresis was evaluated as a diagnostic test for the serodiagnosis of typhoid fever with somatic (O), flagellar (H) and capsular polysaccharide (Vi) antigens of Salmonella typhi on the sera of patients who were blood culture positive (confirmed typhoid cases) or had high Widal agglutination titres, > or = 320, (presumptive typhoid cases) . Of the 37 sera from confirmed cases, 30% showed positivity with O antigen, 24% with H antigens and 51% with Vi antigen . In patients with a presumptive diagnosis, 45% were positive for O antibody, 27% for flagellar antibody and 52% for Vi antibody . When all three antigens were combined the reactivity to any of the antigens was found to be 59% in confirmed typhoid cases, 79% in presumptive typhoid cases and 93% in patients who were simultaneously positive by blood culture and Widal agglutination . However, none of the sera from 45 controls gave a positive precipitation reaction with any of the antigens . It is concluded that counter-current immuno-electrophoresis is a rapid test with low sensitivity and high specificity with Vi antigen, a panel of antigens being most effective, and is, therefore, recommended for rapid diagnosis of typhoid fever.

J Med Microbiol, 1997 Dec, 46(12), 1029 - 38
Enhancement of the specific mucosal IgA response in vivo by interleukin-5 expressed by an attenuated strain of Salmonella serotype Dublin; Whittle BL et al.; It has been shown that cytokines have potential as therapeutic adjuvants in vaccination . Interleukin-5 (IL-5) is a cytokine that regulates antibody production, in particular enhancing IgA production by activated mucosal B cells . This study examined the expression of a cloned cytokine gene encoding murine IL-5 (mIL-5) by an attenuated aroA strain (SL5631) of Salmonella serotype Dublin . The resulting strain, SL5631(pTRXFUS-mIL-5), expressed mIL-5 as a fusion with thioredoxin as demonstrated by immunological and biological assays . When strain SL5631(pTRXFUS-mIL-5) was used as a live vaccine in BALB/c mice, it colonised and multiplied at higher levels in spleens and livers than the strain carrying the empty plasmid . A reduction in invasiveness of SL5631(pTRXFUS-mIL-5) was observed in in-vitro invasion assays . Enhanced IgA response against salmonella LPS in mucosal secretions and enhanced IgA and IgG responses were detected by ELISA and ELISPOT methods in sera of mice immunised with the strain expressing mIL-5 . Results with IL-5-deficient mice showed that the enhanced IgA response was due to Salmonella-expressed mIL-5 rather than endogenous mIL-5.

Biol Pharm Bull, 1997 Nov, 20(11), 1212 - 4
Characterization of two restriction endonucleases, SenPT14bI and SenPT16I, in standard phage-type strains of Salmonella enteritidis; Miyahara M et al.; Two restriction endonucleases (ENases) were found by screening 38 standard phage strains of Salmonella (S.) Enteritidis . An isoschizomer of SacII ENase that recognizes the sequence 5'-CCGC/GG-3' was identified in S . Enteritidis PT14b, and an isoschizomer of XmaIII ENase (5'-C/GGCCG-3') was found in S . Enteritidis PT16 . It is of special interest that the recognition specificities of all known ENases in Salmonella, including those of the S . Enteritidis ENases, are very similar to each other.

Recenti Prog Med, 1997 Oct, 88(10), 459 - 60
Acute intravascular haemolysis with massive microspherocytosis in a 75-year-old woman; Perseghin P et al.; Acute intravascular haemolysis (AIH) sometimes occurs in patients with sepsis or bacteraemia, mainly due to clostridia or Salmonella sp., and may be a life-threatening condition . We describe a case of AIH in a 75-yr-old woman with chronic cholelithiasis . Blood and stool cultures were repeatedly negative, but the massive microspherocytosis, typically observed in clostridia infections, oriented our diagnosis . The patient was treated with antibiotics and for a rapid worsening of her conditions, which could have led to the onset of a multi-organ dysfunction syndrome (MODS), with plasma exchange and, subsequently, haemodialysis, with satisfactory results.

J Clin Microbiol, 1997 Dec, 35(12), 3048 - 53
Distinctive IS200 insertion between gyrA and rcsC genes in Salmonella typhi; Calva E et al.; While probing the vicinity of ompC, a copy of the IS200 insertion element was found between the gyrA and rcsC genes of Salmonella typhi, the causal agent of typhoid fever . This distinctive feature was conserved throughout 63 S . typhi isolates of different geographical origins and was absent from 46 other Salmonella serotypes, including those most associated with human infections, as well as from 19 other enteric bacteria . Furthermore, the location of this IS200 copy corresponds to a constant band, present throughout the 14 PstI S . typhi IS200 fingerprints, encompassing several Vi phage types . Interestingly, an apparently unrelated serotype not frequently associated with human disease, Salmonella weltevreden, contained an IS200 copy at the same position, although it was accompanied by an additional segment of cryptic DNA . On the basis of these findings, PCR assays were designed for molecular typing of S . typhi, and these are potentially useful in studying the epidemiology of typhoid fever.

Scand J Gastroenterol, 1997 Nov, 32(11), 1180 - 2
Salmonellosis: an unusual complication of hepatocellular carcinoma; Simmers TA et al.; Salmonella abscess of a tumor is extremely rare, only three occurrences having been described to date . An unusual case is presented in which Salmonella infantis septicemia was the presenting symptom of multicentric hepatocellular carcinoma in a previously healthy 67-year-old man.

J Inorg Biochem, 1997 Dec, 68(4), 295 - 305
Organotin complexes with pyrrole-2-carboxaldehyde monoacylhydrazones . Synthesis, spectroscopic properties, antimicrobial activity, and genotoxicity; Bergamaschi G et al.; A series of organotin complexes with pyrrole-2-carboxaldehyde 2-hydroxybenzoylhydrazone (H3mfps) and pyrrole-2-carboxaldehyde 2-picolinoylhydrazone (H2mfpp) was investigated . The IR, 1H, and 119Sn nuclear magnetic resonance spectroscopic characterization of all the compounds is reported and discussed in connection with the ligand behaviour of the hydrazone and the structure of the organotin complex . Complexes exhibit antibacterial properties higher than those of the corresponding ligands but they turn out to be less potent than the parent organotin compounds . Sn(H3mfps) (C6H5)2Cl2.2H2O and Sn(Hmfpp)(n-C4H9)2Cl are the most active antibacterial compounds showing MIC values between 3-6 micrograms/ml against Bacillus subtilis and Staphylococcus aureus and between 6-25 micrograms/ml against Escherichia coli; the first compound also strongly inhibits the growth of Aspergillus niger . All the ligands and complexes are devoid of DNA-damaging activity in the Bacillus subtilis rec-assay . H2mfpp and its complexes Sn(Hmfpp)(C2H5)2Cl and Sn3(Hmfpp)(mfpp) (C6H5)3Cl6 are shown by the Salmonella-microsome assay to be mutagenic substances in the presence of a metabolic activation system . The obtained results are discussed on the basis of structure-activity relationships.

Carcinogenesis, 1997 Nov, 18(11), 2149 - 53
Inhibition of 2-amino-3-methylimidazo{4,5-f}quinoline-DNA adducts by indole-3-carbinol: dose-response studies in the rat colon; Xu M et al.; Indole-3-carbinol (I3C) inhibits the formation of colonic aberrant crypt foci and DNA adducts in rats given heterocyclic amine colon carcinogens, such as 2-amino-3-methylimidazo{4,5-f}quinoline (IQ) . Mechanism studies indicate that I3C induces cytochromes P4501A1 and 1A2 (CYP1A1 and CYP1A2), isozymes that respectively metabolize IQ via ring hydroxylation or activate the carcinogen by N-hydroxylation . The present study examined the dose-response for induction of CYP1A1 versus CYP1A2 by I3C, and compared the profiles of induction with the dose-response for inhibition of IQ-DNA adducts in the colon of the F344 rat . Dietary equivalent doses of I3C in the range 100-1000 p.p.m . increased in a dose-related manner both ethoxyresorufin O-deethylase (EROD) and methoxyresorufin O-demethylase (MROD) activities in the liver and colonic mucosa, and Western blots showed a corresponding induction of CYP1A1 and CYP1A2 proteins . However, dietary equivalent doses of I3C in the range 10-25 p.p.m . (i) reduced hepatic EROD and MROD activities and CYP1A protein levels compared with controls, (ii) increased the ratio of CYP1A2 versus CYP1A1, and (iii) activated IQ to a more potent mutagen when liver microsomes from rats given I3C were used for metabolic activation in the Salmonella assay . Rats given a single oral dose of I3C shortly before administering IQ (5 mg/kg body wt, p.o.) exhibited dose-related inhibition of colonic IQ-DNA adducts in the range 25-100 p.p.m . I3C, reaching 95% inhibition at doses > or = 100 p.p.m . I3C, but IQ-DNA adducts were elevated slightly at the lowest I3C dose as compared with the controls . The possible significance of the low versus high dose effects of I3C are discussed in the context of human dietary exposures to I3C and the reported chemopreventive mechanisms of I3C in vivo.

Infect Immun, 1997 Dec, 65(12), 5057 - 66
Characterization of a new region required for macrophage killing by Legionella pneumophila; Segal G et al.; In a previous study, a collection of 55 Legionella pneumophila mutants defective for macrophage killing was isolated by transposon mutagenesis . In this study, nine of these mutants that belong to the same DNA hybridization group (group 3) were characterized . A wild-type DNA fragment that covers this DNA hybridization group was cloned and sequenced . This region was found to contain six new genes (designated icmT, icmS, icmR, icmQ, icmP, and icmO), five of which contain at least one transposon insertion . No transposon insertion was found in icmS . However, this gene was found to be required for macrophage killing, since a kanamycin resistance cassette introduced into icmS by gene replacement resulted in a mutant that was attenuated for macrophage killing . A plasmid containing the DNA fragment that covers this region complements all the mutants for macrophage killing, although various levels of complementation were observed for mutants in different genes . Complementation tests were also performed with plasmids containing one or two of these genes, as well as with plasmids containing nonpolar in-frame deletions . The results from these complementation tests indicated that all six genes located in this region are needed for macrophage killing and that they are probably arranged as two transcriptional units (icmTS and icmPO) and two genes (icmR and icmQ) . A region upstream of the coding sequence of several icm genes may contain a potential promoter and/or regulatory site . Homology searches show that icmP and icmO bear significant homology to the trbA and trbC genes from the Salmonella R64 plasmid, respectively . The sequences of the other four genes do not show significant homology with any entries in sequence databases.

J Bacteriol, 1997 Dec, 179(23), 7595 - 9
Proteins induced in Escherichia coli by benzoic acid; Lambert LA et al.; Proteins induced by benzoic acid in Escherichia coli were observed on two-dimensional electrophoretic gels (2-D gels) . Cultures were grown in glucose-rich medium in the presence or absence of 20 mM benzoate at an external pH of 6.5, where the pH gradient (deltapH) is large and benzoate accumulates, and at an external pH of 8.0, where deltapH is inverted and little benzoate is taken up . Radiolabeled proteins were separated on 2-D gels and were identified on the basis of the index of VanBogelen and Neidhardt . In the absence of benzoic acid, little difference was seen between pH 6.5 and pH 8.0; this confirms that the mechanisms of protein homeostasis in this range are constitutive, including the transition between positive and inverted deltapH . Addition of benzoate at pH 6.5 increased the expression of 33 proteins . Twelve of the benzoate-induced proteins were induced at pH 8.0 as well, and nine of these matched proteins induced by the uncoupler dinitrophenol . Eighteen proteins were induced by benzoate only at pH 6.5, not at pH 8.0, and were not induced by dinitrophenol . One may be the iron and pH regulator Fur, which regulates acid tolerance in Salmonella spp . The other 13 proteins had not been identified previously . The proteins induced by benzoate only at a low pH may reflect responses to internal acidification or to accumulation of benzoate.

Mutat Res, 1997 Oct 24, 393(3), 189 - 97
Genetic toxicity studies of 1,2,3,4-tetrahydro-9-acridinamine (tacrine); Zeiger E et al.; The mutagenicity and clastogenicity of 1,2,3,4-tetrahydro-9-acridinamine (tacrine) were studied in vitro using the Salmonella mutagenicity test and the induction of chromosome aberrations in Chinese hamster ovary (CHO) cells, and in the mouse bone marrow micronucleus test in vivo . This chemical is currently being used to treat dementia arising from Alzheimer's Disease . Tacrine was mutagenic in Salmonella but did not produce chromosome damage in CHO cells or in mouse bone marrow cells . A clear mutagenic response was seen in strain TA97 with rat and hamster liver S9; inconsistent results were obtained without S9 . No mutagenicity was seen in strains TA98 and TA100 without S9, and inconsistent results were seen with S9 . There was no induction of chromosome aberrations in cultured CHO cells with or without S9 . Oral administration to mice of tacrine daily for three days did not result in the induction of micronuclei in their bone marrow cells . The mutagenic response in Salmonella, and the structure of the molecule, suggests that tacrine may be carcinogenic when tested in rodents . This information must be considered when preparing benefit-risk determinations for medical uses of this substance.

Crit Rev Oral Biol Med, 1997, 8(4), 389 - 409
Models of invasion of enteric and periodontal pathogens into epithelial cells: a comparative analysis; Meyer DH et al.; Bacterial invasion of epithelial cells is associated with the initiation of infection by many bacteria . To carry out this action, bacteria have developed remarkable processes and mechanisms that co-opt host cell function and stimulate their own uptake and adaptation to the environment of the host cell . Two general types of invasion processes have been observed . In one type, the pathogens (e.g., Salmonella and Yersinia spp.) remain in the vacuole in which they are internalized and replicate within the vacuole . In the other type, the organism (e.g., Actinobacillus actinomycetemcomitans, Shigella flexneri, and Listeria monocytogenes) is able to escape from the vacuole, replicate in the host cell cytoplasm, and spread to adjacent host cells . The much-studied enteropathogenic bacteria usurp primarily host cell microfilaments for entry . Those organisms which can escape from the vacuole do so by means of hemolytic factors and C type phospholipases . The cell-to-cell spread of these organisms is mediated by microfilaments . The investigation of invasion by periodontopathogens is in its infancy in comparison with that of the enteric pathogens . However, studies to date on two invasive periodontopathogens . A actinomycetemcomitans and Porphyromonas (Bacteroides) gingivalis, reveal that these bacteria have developed invasion strategies and mechanisms similar to those of the enteropathogens . Entry of A . actinomycetemcomitans is mediated by microfilaments, whereas entry of P . gingivalis is mediated by both microfilaments and microtubules . A . actinomycetemcomitans, like Shigella and Listeria, can escape from the vacuole and spread to adjacent cells . However, the spread of A . actinomycetemcomitans is linked to host cell microtubules, not microfilaments . The paradigms presented establish that bacteria which cause chronic infections, such as periodontitis, and bacteria which cause acute diseases, such as dysentery, have developed similar invasion strategies.

Nippon Saikingaku Zasshi, 1997 Oct, 52(4), 735 - 46
{Studies on bacillary dysentery cases of overseas travellers--during 1979 to 1995}; Ueda Y et al.; A total of 36,780,440 overseas travellers during 1979-1995 (17 years) were quarantined at Osaka and Kansai Airport Quarantine Station, 84,777 travellers reported themselves suffer from diarrhoea . Stools from 29,587 persons were bacteriologically examined . Various enteropathogenic bacteria were isolated from 9,766 (33.0%) patients of the stools examined . Isolated species were as follows: Plesiomonas shigelloides (3,234 cases); Salmonella spp . (2,236 cases); enterotoxgenic Escherichia coli (1,621 cases); Vibrio parahaemolyticus (1,959 cases); and Shigella spp . (1,242 cases) . 1,278 different Shigella strains were isolated from 1,242 cases who were thus diagnosed as bacillary dysentery patients . The suspected regions or countries for infection of these cases were analysed . The serovars and antibiotic-sensitivities of the isolated strains were examined . Colicine typing of S . sonnei strains were also done . The results can be summarized as follows . 1) The most cases (53.4%) were infected in India . 2) The percentage distribution of sub-species of the strains was as follows; S . sonnei (57.8%), S flexneri (29.8%), S . boydii (8.4%), and S . dysenteriae (4.0%), respectively . 3) The major colicine type of S . sonnei strains were type 6 and 0 . 4) The percentage of Antibiotic-resistant strains of each sub-species was S . dysenteriae (92.2%), S . sonnei (89.4%), S . flexneri (87.1%), and S . boydii (84.9%), respectively . The percentage of Antibiotic-resistant strains of S . flexneri were increased annually.

Arch Dis Child, 1997 Oct, 77(4), 345 - 6
Salmonella infection acquired from reptilian pets; Sanyal D et al.; Two children presented with signs and symptoms of gastroenteritis . Salmonella chameleon was isolated from the stool of one child and also from an iguana kept in the home as a pet . Salmonella arizonae was isolated from the stool of the other child and also from four snakes sharing the same household . Exotic reptiles are unsuitable pets to share the home environment with infants.

Food Addit Contam, 1997 Aug-Oct, 14(6-7), 695 - 703
Purity of recycled fibre-based materials; Sipilainen-Malm T et al.; In order to study the purity of recycled fibre-based materials, products containing recycled fibre as well as recycled pulp were examined with regard to their chemical impurities, toxicity and microbiological quality . The study was carried out to clarify both qualitatively and quantitatively the variations in microbiological quality . The levels of several classes of chemical substances were analysed and semi-volatile and volatile substances identified . The toxicity and mutagenicity of virgin fibre and recycled fibre materials were screened using the Photobacter toxicity test and the Ames Salmonella mutagenicity test . Preliminary chemical characterization of the mutagens was carried out . Identification of the compounds found in the mutagenic fractions was performed by gas chromatography/mass spectrometry (GC/MS) . The concentration of various substances analysed was found to be low, although the variety of substances present appeared to be very broad . Preliminary chemical characterization revealed that some samples contained compounds known to have mutagenic or other toxic activity . Also, the recycled fibre pulps contained large amounts of various microbes, the microbial load consisting mainly of aerobic spore-forming bacteria . The paper-making process was found to clearly have reduced the total microbial counts.

Immunotechnology, 1995 Aug, 1(2), 139 - 50
Bifunctional fusion proteins consisting of a single-chain antibody and an engineered lanthanide-binding protein; MacKenzie CR et al.; The combination of an antibody fragment with a lanthanide chelating protein has desirable characteristics for fluorescence-based immunoassays and tumor radioimmunotherapy . As a model for this design, a fusion protein consisting of a single-chain antibody linked to an engineered version of oncomodulin, a protein with two Ca(2+)-binding motifs (the CD and EF loops), was produced by secretion from Escherichia coli in good yield . The single-chain antibody was specific for a Salmonella O-polysaccharide . The CD loop of oncomodulin had been redesigned to bind lanthanide ions with high affinity . The fusion protein was shown to have antigen-binding activity that was comparable to that of the unfused single-chain antibody, to bind Tb3+ with very high affinity and to give strong, sensitized Tb3+ luminescence via excitation of the tryptophan residue in the CD loop . A second fusion protein containing a 30-residue helix-loop-helix motif as the lanthanide-binding component was also prepared, but showed considerably lower solubility . Competition for Tb3+ binding by a series of metal chelators indicated that the affinities of the oncomodulin and 30 residue fusions for Tb3+ were approximately 10(11) M-1 and 10(7) M-1, respectively . Time-resolved lanthanide luminescence photography of electrophoresis gels demonstrated that the helix-loop-helix Ca(2+)-binding could be used to specifically visualize the scFv fragment.

Immunology, 1997 Sep, 92(1), 146 - 52
Identification of specific recognition molecules on murine mononuclear phagocytes and B lymphocytes for Vi capsular polysaccharide: modulation of MHC class II expression on stimulation with the polysaccharide; Qadri A; Vi bacterial polysaccharide is a homopolymer of alpha 1-4 N-acetyl polygalacturonic acid with variable O-acetylation at position C-3 and forms a capsule around many bacteria . It has been referred to as the virulence factor of Salmonella typhi and is also a candidate vaccine against typhoid fever . The present study reports the interaction of this polysaccharide with murine mononuclear phagocytes and lymphocytes, and with human monocytes . Vi showed a dose-dependent binding to the murine monocyte cell lines WEHI-274.1 and J774 . This binding was abrogated if the polysaccharide was deacetylated, suggesting involvement of acetyl groups in this interaction . Vi also bound to the murine B-cell lymphoma line A20, to peritoneal exudate cells and to a lesser degree to spleen cells and thymocytes from BALB/c mice . The polysaccharide also interacted with the human histiocytic lymphoma line U937 but not with the human monocyte cell line THP-1 . Stimulation with Vi led to up-regulation of surface major histocompatibility complex (MHC) class II expression on A20 cells . Immunoprecipitation of Vi-bound molecules from cell surface biotinylated A20 and WEHI-274.1 revealed two bands with MW of about 32,000 and 36,000 . The study demonstrates that Vi capsular polysaccharide can interact with mononuclear phagocytes and lymphocytes through specific cell surface molecules and modulate MHC class II expression.

Ann Rheum Dis, 1997 Sep, 56(9), 516 - 20
Long-term prognosis of reactive salmonella arthritis; Leirisalo-Repo M et al.; OBJECTIVES: Reactive joint complications triggered by salmonella gastroenteritis are increasingly reported, but the outcome and long term prognosis of the patients is incompletely known . This study looked at the prognosis of salmonella arthritis in patients hospitalised in 1970-1986 . METHODS: Hospital records from two hospitals in southern Finland were screened for patients with the discharge diagnosis of salmonellosis or reactive, postinfectious arthritis or Reiter's disease . For the patients with confirmed diagnosis of reactive salmonella arthritis, data about the acute disease were collected from the hospital records . A follow up study was performed . RESULTS: There were 63 patients (28 women, 35 men, mean age 36.5 years) with salmonella arthritis . Urethritis occurred in 27%, eye inflammation in 13%, and low back pain in 44% of the patients . HLA-B27 was present in 88% . More men than women were HLA-B27 positive . HLA-B27 positive patients had higher erythrocyte sedimentation rate (mean 80.9 v 46.5 mm 1st h, p = 0.0180) . Also, extra-articular features and radiological sacroiliitis were seen only in HLA-B27 positive patients . A follow up study was performed on 50 patients mean 11.0 (range 5-22 years) later . Twenty patients had recovered completely . Ten patients had mild joint symptoms, 11 patients had had a new acute transient arthritis, and five acute iritis . Eight patients had developed chronic spondyloarthropathy . Radiological sacroiliitis was seen in six of 44 patients, more frequently in male than in female patients (32% v 0%; p = 0.0289) . Recurrent or chronic arthritis, iritis or radiological sacroiliitis developed only in HLA-B27 positive patients . CONCLUSION: Joint symptoms are common after reactive salmonella arthritis . HLA-B27 contributes to the severity of acute disease and to the late prognosis.

Chest, 1997 Nov 5, 112(5), 1197 - 201
Salmonella lung involvement in patients with HIV infection; Casado JL et al.; STUDY OBJECTIVE: To determine the frequency, clinical features, and outcome of lung involvement in HIV-infected patients having nontyphoid strains of Salmonella bacteremia . DESIGN: A retrospective clinical study . PATIENTS AND SETTING: We studied the records of all HIV-infected patients with Salmonella bacteremia diagnosed at a university tertiary hospital from January 1987 to December 1995 . RESULTS: Lung involvement was found in 18 (35.3%) of 51 HIV-infected individuals with Salmonella bacteremia . Six of 18 (33.3%) were diagnosed as having definite Salmonella pulmonary infection by isolation of Salmonella from respiratory specimens, while probable Salmonella lung disease was considered in two patients who developed lung abscesses without the identification of any pathogen . Predisposing factors for focal disease, such as prior lung disease or Salmonella serotype, were equally prevalent regardless of the presence of Salmonella pulmonary involvement . Cavitary infiltrates or abscess formation were seen in five of the eight patients . With the exception of one patient coinfected with Nocardia asteroides who died 1 month later, all patients were cured with antibiotic treatment . Superinfection with other pulmonary pathogens (10 cases, 56%) was more frequent than Salmonella pneumonia; the most frequent alternative diagnosis was Pneumocystis carinii pneumonia (5 cases, 28%), pyogenic bacterial infection (17%), and tuberculosis (11%) . CONCLUSIONS: In HIV-infected patients with Salmonella bacteremia, lung involvement is frequent, although there were no significant factors to explain this association . Cavitary disease was the most common radiologic pattern, and focal lung disease due to Salmonella does not seem to be associated with a worse prognosis . Coinfection and superinfection with other respiratory pathogens are more common than isolated Salmonella lung disease, and therefore, additional diagnostic procedures must be considered in the evaluation of these patients.

J Zoo Wildl Med, 1997 Sep, 28(3), 331 - 5
Tracheal malformation in a bicephalic Honduran milk snake (Lampropeltis hondurensis) and subsequent fatal Salmonella arizonae infection; Oros J et al.; A bicephalic Honduran milk snake (Lampropeltis hondurensis) with tracheal duplication and malformation and Salmonella arizonae infection is described . There were atypically wide collapsed tracheal rings with necrotizing tracheitis and abundant necrotic epithelial debris and inflammatory cells obstructing the lumen in one of the duplicate tracheae . Salmonella arizonae was cultured from the malformed duplicate trachea and was considered to be the etiologic agent causing necrosis.

J Trop Pediatr, 1997 Oct, 43(5), 307 - 10
Evaluation of Teknaf Enteric Agar (TEA): A modified MacConkey's Agar for the isolation of Shigella dysenteriae type 1 and Shigella flexneri; Munshi MM et al.; To develop a better and selective medium for the isolation of Shigella spp., MacConkey's Agar (MAC) was modified by adding potassium tellurite (K2TeO3) at a concentration of 1 microgram/ml . The formulation designated Teknaf Enteric Agar (TEA) was studied for the inhibitory effect of potassium tellurite on the growth of different enteric bacteria, and as a medium for isolating Shigella spp . from clinical stool samples (n = 3125) . We observed that the growth of E . coli was effectively inhibited on TEA with no effect on the growth of S . dysenteriae type 1 and S . flexneri . A total of 2019 Shigellae were isolated through the combined use of TEA, MAC, and Salmonella-Shigella Agar (SS) . On TEA, 1921 S . dysenteriae type 1 and S . flexneri were isolated as compared to 1765 from the combined use of MAC and SS . A total of 194 of S . dysenteriae type 1 and S . flexneri were exclusively isolated from TEA as compared to 38 which were only made from MAC and SS . We conclude that TEA significantly increased the overall isolation rate of Shigella spp . as compared to the combined use of MAC and SS (P < 0.0001), although it is not suitable for the isolation of S . sonnei.

Mol Microbiol, 1997 Sep, 25(5), 903 - 12
A secreted effector protein of Salmonella dublin is translocated into eukaryotic cells and mediates inflammation and fluid secretion in infected ileal mucosa; Galyov EE et al.; Enteritis induced by non-typhoid pathogenic Salmonella is characterized by fluid secretion and inflammatory responses in the infected ileum . The inflammatory response provoked by Salmonella initially consists largely of a neutrophil (PMN) migration into the intestinal mucosa and the gut lumen . The interactions between Salmonella and intestinal epithelial cells are known to play an essential role in inducing the inflammatory response . Upon interaction with epithelial cells salmonellae are able to elicit transepithelial signalling to neutrophils . This signalling is recognized as a key virulence feature underlying Salmonella-induced enteritis . However, the nature and mechanism of such signalling has not been clarified to date . Here, we characterize SopB, a novel secreted effector protein of Salmonella dublin, and present data implying that SopB is translocated into eukaryotic cells via a sip-dependent pathway to promote fluid secretion and inflammatory responses in the infected ileum.

Vaccine, 1997 Nov, 15(16), 1737 - 40
The immune response to a B-cell epitope delivered by Salmonella is enhanced by prior immunological experience; Whittle BL et al.; Attenuated, heterologous strains of Salmonella have shown potential as live, recombinant vaccines against foreign pathogens . Studies in animal models have demonstrated that immunization with these heterologous vaccines is an effective way to induce both cellular and humoral immune responses against Salmonella and the foreign antigen . We studied the consequence of priming mice with Salmonella dublin 3-6 months before intraperitoneal administration with the same strain carrying a model B-cell epitope . Mice primed with the carrier strain demonstrated enhanced serum Ig titres against the foreign antigen . This immune enhancement was observed up to approximately 6 months after priming . These findings suggest that previous immunological experience with Salmonella does not limit the immune response to a foreign antigen carried by the same organism . In fact, prior exposure to Salmonella appears to enhance the response to the foreign antigen.

J Pharm Pharmacol, 1997 Oct, 49(10), 1042 - 4
A xanthanolide with potent antibacterial activity against methicillin-resistant Staphylococcus aureus; Sato Y et al.; This study was conducted to find constituents of an annual herb, Xanthium sibiricum Patr er Widd, with effective antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) . By monitoring antibacterial activity against MRSA strains, it was shown that a sesquiterpene lactone, identified as {3aR-(3a alpha, 7 beta,8a beta)}-3,3a,4,7,8,8a-hexahydro-7- methyl-3-methylene-6-(3-oxo-1-butenyl)-2H-cyclohepta{b}furan-2-one, or xanthatin, isolated from leaves of the herb, had outstandingly potent activity against S . aureus species, including MRSA; its activity against MRSA and MSSA strains was similar . Other bacteria, e.g . Staphylococcus epidermidis, Klebsiella pneumoniae, Bacillus cereus, Pseudomonas aeruginosa and Salmonella typhi, were also susceptible at the concentrations tested but the compound had no inhibitory effect on some other bacteria, including Escherichia coli . The results show that xanthatin has outstandingly potent activity against strains of S . aureus but that the activity of the compound is highly species-specific.

J Pediatr Orthop, 1997 Jul-Aug, 17(4), 463 - 6
Salmonella pelvic osteomyelitis in normal children: report of two cases and a review of the literature; Sucato DJ et al.; We report two cases of salmonella osteomyelitis isolated to the pelvis in white adolescents aged 12 and 16 years . No underlying medical condition predisposed these children to salmonella osteomyelitis, and the clinical course was prolonged before definitive diagnosis . The key to diagnosis and the localization of the site of the pathologic condition was made from radionuclide studies performed 2-3 weeks from the onset of symptoms . Clinicians should be aware of isolated salmonella osteomyelitis of the pelvis in normal children, especially when imaging studies are normal at initial presentation . Technetium-labeled bone scans may be normal < or = 2 weeks from the onset of symptoms . Definitive diagnostic testing should include a gallium scan and computed tomography scan when technetium bone scans are negative . Treatment with antibiotics alone is successful.

Acta Paediatr Jpn, 1997 Oct, 39(5), 624 - 5
Imipenem for treatment of relapsing Salmonella meningitis in a newborn infant; Koc E et al.; Salmonella meningitis is a rare clinical entity that occurs mainly during early infancy . Treatment of Salmonella infections may be complicated by the bacteria's growing resistance to clinically important antimicrobial agents, especially third-generation cephalosporins . A report is presented of a newborn infant with Salmonella meningitis who relapsed after 4 weeks of cefotaxime treatment and was cured completely with imipenem cilastatin therapy.

Epidemiol Infect, 1997 Oct, 119(2), 121 - 6
Incidence and clinical symptoms of Aeromonas-associated travellers' diarrhoea in Tokyo; Yamada S et al.; In a survey examining the causes of travellers' diarrhoea treated in Tokyo between July 1986 and December 1995, Aeromonas species were isolated from 1265 (5.5%) of 23,215 travellers returning from developing countries . Aeromonas species were the fourth most frequent enteropathogen isolated, following enterotoxigenic E . coli (8.5%), Salmonella spp . (7.6%) and Plesiomonas shigelloides (5.6%) . Aeromonas species were found in 1191 (5.6%) of 21,257 patients with diarrhoea and in 74 (3.8%) of 1958 healthy individuals without diarrhoea . Mixed infection was observed in 512 (40.5%) cases . No significant difference in the prevalence of Aeromonas by year, season, age distributions, or sex was observed, but a slight difference was noted depending on the country where the travellers visited . Of the 1265 Aeromonas isolates, 893 strains (70.6%) were A . veronii biovar sobria, 330 (26.1%) were A . hydrophila, and 42 (3.3%) were A . caviae . The clinical symptoms of patients from whom Aeromonas species was isolated as the only potential enteric pathogen were almost similar, which were watery diarrhoea (about 60%), abdominal cramps (43%), fever (around 15%), and nausea or vomiting (13%) . Although the severity of illness was milder than that of enterotoxigenic E . coli alone, these data suggest that Aeromonas species are important enteric pathogens in travellers' diarrhoea.

Zentralbl Bakteriol, 1997 Oct, 286(3), 371 - 82
Importance of the serovar-specific plasmid for virulence of salmonella strains in calves; Steinbach G et al.; To evaluate the influence of serovar-specific plasmids on salmonella virulence in calves, experiments were performed involving infection, by the oral route, with mixtures of strains containing equal counts of a plasmid-carrying and a plasmid-free strain of the same serovar . The concentration ratio between the plasmid-carrying and the plasmid-free strain which had developed in the organs of the infected animals was used for a comparative evaluation of virulence and pathogenetic behaviour of the strains . While in the S . typhimurium strains studied, the presence of the plasmid was accompanied by a significantly increased colonization and multiplication of the agent in the host's body, examination of S . enteritidis and S . dublin revealed that the plasmid-free strains exhibited identical or even significantly higher bacterial counts than the plasmid-carrying strains in organs . The fact that plasmid-free salmonella strains with a high virulence for calves have been found demonstrates that the presence of a serovar-specific plasmid is not an indispensable requirement for the development of salmonellosis in calves.

J Dairy Sci, 1997 Oct, 80(10), 2673 - 81
Manure and microbes: public and animal health problem?
Pell AN.
Most environmental concerns about waste management either have focused on the effects of nutrients, especially N and P, on water quality or have emphasized odor problems and air quality . Microbes from manure are often low on the priority list for control and remediation, despite the fact that several outbreaks of gastroenteritis have been traced to livestock operations . The pathogens discussed in this paper include protozoans (Cryptosporidium parvum, Giardia spp.), bacteria (Listeria monocytogenes, Escherichia coli O157:H7, Salmonella spp., and Mycobacterium paratuberculosis), and some enteric viruses . Clinical symptoms, prospects for zoonotic infection, and control methods other than the use of antimicrobials are considered . Recommendations to avoid disease transmission include taking steps to ensure the provision of clean, unstressful environments to reduce disease susceptibility and the careful handling and spreading of manure from animals at high risk for infection, especially young calves . Composting and drying of manure decrease the number of viable pathogens . Environmental controls, such as filter strips, also reduce the risk of water contamination.

Scand J Infect Dis, 1997, 29(4), 423 - 4
Splenic abscess caused by Salmonella braenderup, treated with percutaneous drainage and antibiotics; Rorbakken G et al.; Splenic abscess is a rare condition and its optimal treatment is still debated . We report on a 17-year-old immunocompetent female patient, hospitalized with Salmonella braenderup gastroenteritis and splenic abscess, who was treated with ciprofloxacin, percutaneous catheter drainage and despite remaining drainage of 50 ml/24 h, the catheter was removed and the antibiotic treatment was stopped when the fluid was clear . Following removal a transient increase in the size of the splenic cavity was observed, but without any clinical symptoms or deterioration of laboratory parameters . At the 1-year follow-up, ultrasound examination of the spleen disclosed only a 8 mm scar.

Mil Med, 1997 Nov, 162(11), 766 - 8
Frequency of infected aneurysms among patients in Department of Veterans Affairs hospitals, 1986-1990: the role of Salmonella; Klontz KC; Patients with infected aneurysms discharged from Department of Veterans Affairs hospitals during fiscal years 1986 to 1990 were identified using International Classification of Diseases codes to determine the proportion of patients infected with Salmonella . Twenty-three patients with infected aneurysms were identified . All patients were males; the median age was 63 years . A Gram-positive organism was recovered from 16 patients (70%), a Gram-negative organism from 6 patients (26%), and a fungus from 1 patient . Three patients, all with aneurysms of the abdominal aorta, were infected with Salmonella . Overall, the vessels most often involved included arteries of the extremities (10 patients) and the abdominal or thoracic aorta (9 patients) . An increased incidence of nontyphoidal salmonellosis in the United States during the last few decades, along with an aging of the U.S . population, suggests that Salmonella can be expected to maintain a niche in the bacteriology of infected aneurysms.

Mutat Res, 1997 Sep 18, 393(1-2), 115 - 22
Possible mechanisms of antimutagens by various teas as judged by their effects on mutagenesis by 2-amino-3-methylimidazo{4,5-f}quinoline and benzo{a}pyrene; Chen HY et al.; Possible mechanisms of antimutagenicity of various tea extracts (green, pouchong, oolong and black tea) toward 2-amino-3-methylimidazo{4,5-f}quinoline (IQ) and benzo{a}pyrene (B{a}P) were investigated using a Salmonella/microsome assay . Tea extracts exhibited no inhibitory effects toward IQ and B{a}P in bio-antimutagenic assays, indicating that their antimutagenic activity is desmutagenic in nature . The mutagenicities of IQ and B{a}P decreased as the reaction periods of tea extracts with promutagens, S9 mix, or mutagen metabolites increased . The antimutagenicity of tea extracts toward IQ could be attributed (primarily) to an interaction between tea extracts and S9 mix . Apart from their interaction with S9 mix, tea extracts also exhibited antimutagenicity by markedly decreasing the mutagenicity of B{a}P metabolites . These results suggest that tea extracts: (1) inhibit the cytochrome P-450-mediated metabolism of IQ and B{a}P to their ultimate mutagenic metabolite form; and (2) interact with both promutagens and their metabolites in such a way as to reduce their mutagenic potentials . Therefore, the antimutagenic actions of tea extracts are due to a combination of the above distinctive mechanisms, and can vary with the type of mutagen under test.

Mutat Res, 1997 Sep 18, 393(1-2), 23 - 35
Genotoxicity induced in human lymphoblasts by atmospheric reaction products of naphthalene and phenanthrene; Sasaki JC et al.; The genotoxic risks from exposure to polycyclic aromatic hydrocarbons (PAH) have long been recognized . Less well understood are the potential genotoxic risks of the atmospheric reaction products of this class of compounds . In this investigation, we have utilized several human cell genotoxicity assays to evaluate naphthalene, phenanthrene, and their atmospheric reaction products 1-nitronaphthalene, 2-nitronaphthalene, 1-hydroxy-2-nitronaphthalene, 2-hydroxy-1-nitronaphthalene, 1,4-naphthoquinone and 2-nitrodibenzopyranone . In addition, reaction products of naphthalene were generated in a 6700-1 Teflon environmental chamber, collected on a solid adsorbent, extracted and fractionated by normal-phase HPLC . Individual fractions were then analyzed using GC-MS, and tested for genotoxicity . Genotoxicity was determined using the human B-lymphoblastoid cell line, MCL-5, which expresses several transfected P450 and epoxide hydrolase genes . Mutagenicity was evaluated at both the heterozygous tk locus and the hemizygous hprt locus, permitting detection of both intragenic and chromosomal scale mutational events . Test compounds were also screened using the CREST modified micronucleus assay . Genotoxicity results indicate that 2-nitronaphthalene and 2-nitrodibenzopyranone possess greater mutagenic potency than their parent compounds, and interestingly, both compounds induced significant increases in mutation frequency at tk but not hprt . These results suggest a mechanistic difference in human cell response as compared to bacteria, where both compounds were previously shown to induce point mutations in the Salmonella reversion assay . The genotoxicity of 2-nitronaphthalene and 2-nitrodibenzopyranone in human cells, together with their high concentrations in ambient air relative to nitro-PAH directly emitted from combustion sources, emphasizes the need to consider atmospheric reaction products of PAH in genotoxicity assessments.

Mutat Res, 1997 Sep 18, 393(1-2), 7 - 15
Evaluation of the genotoxic potential of alkylalkanolamines; Leung HW et al.; Three alkylalkanolamines, N,N-dimethylethanolamine, N-methyldiethanolamine, and tert-butyldiethanolamine, were evaluated for potential genotoxic activity using the Salmonella/microsome reverse gene mutation test, the CHO/HGPRT forward gene mutation test, a sister chromatid exchange test in cultured CHO cells, and an in vivo peripheral blood micronucleus test in Swiss-Webster mice . None of the three alkylalkanolamines produced any significant or dose-related increases in the frequencies of mutations, sister chromatid exchanges or micronuclei . These results indicate that N,N-dimethylethanolamine, N-methyldiethanolamine, and tert-butyldiethanolamine are not genotoxic in the tests conducted.

Indian J Exp Biol, 1997 Jun, 35(6), 668 - 9
PCR amplification of ribosomal DNA spacer regions of Salmonella enteritidis isolates; Chaudhuri P et al.; Polymerase chain reaction (PCR) was used to amplify ribosomal DNA spacer regions from nine Salmonella enteritidis field isolates . Unique products of 480 and 660 bp were obtained from the isolates . PCR product (480bp) was then cloned into pUC18 vector by blunt end ligation.

Avian Dis, 1997 Jul-Sep, 41(3), 732 - 7
Genotypic evaluation of Salmonella enteritidis isolates of known phage types by arbitrarily primed polymerase chain reaction; Fadl AA et al.; Salmonella enteritidis isolates of known phage types 8, 13a, and 14b were inoculated separately into a group of 14-wk-old specific-pathogen-free chickens . S . enteritidis isolates from pre- and postinoculum were analyzed with the use of arbitrarily primed polymerase chain reaction to determine any genotypic changes after reisolation from the chickens . The preinoculum isolates and the isolates of S . enteritidis recovered at 5, 10, 20, and 35 days postinoculation from the inoculated chickens with various phage types were similar . Therefore, no changes of S . enteritidis organisms of similar phage types occurred at the genotypic level . However, SE-3-B7001 (phage type 8) was changed to phage type 14b after inoculation into the chickens.

Avian Dis, 1997 Jul-Sep, 41(3), 709 - 13
Comparison of drag-swab environmental protocols for the isolation of Salmonella in poultry houses; Byrd JA et al.; Three surveys were conducted during November 1995 and March and May 1996 to compare the use of double-strength skim milk (wet) or no transport media (dry) drag swabs for the detection of salmonellae in 10 broiler houses . Salmonellae were isolated from 57 of 120 individual wet drag-swab samples, compared with 21 of 120 dry drag-swab samples . Furthermore, Salmonella was detected at a higher frequency with wet drag swabs (66.7%) than with dry drag swabs (40%) when compared on an individual growout house basis . A total of seven different serotypes were isolated from the 10 broiler houses . Although double-strength skim milk drag swabs are more labor intensive than dry drag swabs, double-strength skim milk drag swabs are more efficient for detecting Salmonella than are dry drag swabs with no transport media.

Avian Dis, 1997 Jul-Sep, 41(3), 559 - 67
Differences in frequency, level, and duration of cecal carriage between four outbred chicken lines infected orally with Salmonella enteritidis; Duchet-Suchaux M et al.; Four chicken lines, L2, B13, PA12 (egg-type), and Y11 (meat-type), were tested for experimental carrier state of Salmonella enteritidis (SE) in two identical trials . After oral inoculation of SE at 1 wk of age with 5 x 10(4) SE colony-forming units (CFU), 10 chickens per line were necropsied weekly for 6 wk and then every 8 or 15 days until the 12th week postinoculation (PI) . Liver, spleen, ovary, and ceca were examined for level of SE colonization . Numbers of positive livers and spleens and levels of the challenge strain in these organs differed little between the four chicken lines . Only three positive ovaries were detected . According to the chicken line, ceca exhibited generally significant (P < 0.05) differences in the number of positive organs during weeks 5-11 PI, in the SE CFU levels (P < 0.05) in the first 5 wk PI and during weeks 8 and 10 PI, and in the duration of colonization . L2 and B13 chickens generally carried SE in their ceca at higher levels, in more animals, and for a longer time than PA12 and Y11 chickens . Y11 chickens were the most resistant to SE cecal colonization.

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