Salmonella

Trop Med Int Health, 1999 Mar, 4(3), 211 - 5
Outcome in three groups of patients with typhoid fever in Indonesia between 1948 and 1990; van den Bergh ET et al.; The outcome in three groups of patients with bacteriologically confirmed typhoid fever caused by Salmonella typhi, treated during three episodes between 1948 and 1990 in Java, Indonesia, was compared by retrospective analysis of hospital records . The study population consisted of three groups of patients . Group I (n = 50) was treated in Batavia (the present Jakarta) from 1948 to 1950, Group II (n = 61) in Yogyakarta from 1952 to 1956, Group III (n = 105) in Semarang from 1989 to 1990 . Main outcome measures were days until defervescence, early relapses during hospitalization, duration of hospital stay, complications and mortality . Group I received supportive treatment only, Group II low doses of chloramphenicol (total 12.5 g) and Group III full doses of chloramphenicol (total 27 g); occasionally other antibiotics were used . In Group I, II and III the mean number of days until defervescence was 16, 8 and 6 and the mean number of days in hospital 43, 47 and 15, respectively . Mortality was 26%, 10% and 5% and complications occurred in 38%, 18% and 13%, respectively . Between Group I and Group II the differences in mortality and complications were statistically significant (P < 0.05) . Compared to Group I the proportion of early relapses was higher in Group II, but was zero in Group III . There were significantly fewer gastrointestinal complications in Group II than in Group I (P < 0.01) and even fewer in Group III . When no antibiotic against S . typhi was available, typhoid fever had a protracted course, and only 74% of patients survived . Even with low dosages of chloramphenicol, defervescence was earlier and mortality and complications decreased dramatically, but early relapses were frequent . Full doses of chloramphenicol for a sufficient period of time only slightly reduced mortality and complications further, but eliminated early relapses completely.

J Colloid Interface Sci, 1999 May 15, 213(2), 557 - 564
Thermodynamics and Structural Studies of the Interaction of Polymyxin B with Deep Rough Mutant Lipopolysaccharides; Koch PJ et al.; Deep rough mutant lipopolysaccharide (ReLPS) dissolved in aqueous solution spontaneously forms supramolecular structures which mainly consist of vesicles . Addition of Polymyxin B (PmB) to these ReLPS vesicles influence the shape of these structures as demonstrated here by electronmicroscopy and dynamic light scattering techniques . The main phase transition of the ReLPS is found at 21.3 +/- 0.1 degrees C for ReLPS from Escherichia coli and at 24.0 +/- 0.5 degrees C for ReLPS from Salmonella minnesota by differential scanning calorimetry (DSC) . Using isothermal differential titration calorimetry (ITC), the thermodynamic behavior of the interaction of PmB with ReLPS vesicles has been studied . The stoichiometric ratio for the binding of PmB to ReLPS was found to lie between 0.6 and 1, as determined from ITC and monolayer experiments . No phase transition was observed for ReLPS monolayers saturated with PmB . The results indicate specific interaction of PmB with ReLPS . We propose a two-step mechanism for this interaction, which involves electrostatic attraction between charged parts of the molecules and, in the second step, hydrophobic interactions between the nonpolar parts of both compounds .

J Cardiovasc Surg (Torino), 1999 Feb, 40(1), 31 - 5
Primary aorto-duodenal fistula secondary to infected abdominal aortic aneurysms: the role of local debridement and extra-anatomic bypass; Pagni S et al.; Gastrointestinal bleeding secondary to spontaneous rupture of an infected abdominal aortic aneurysm into the duodenum is a rare and highly lethal clinical occurrence, representing roughly a third of all primary aortoduodenal fistulas . Diagnosis is problematic due to the subtleties in the clinical presentation and course, and surgical treatment is usually delayed, representing a challenge even for the experienced vascular surgeon . The overall mortality is over 30% and the operative approaches are still controversial . Two cases of ruptured infrarenal aortic aneurysms complicated with aortoduodenal fistula were recently treated at our institution . Bacterial aortitis was documented by arterial wall cultures positive for Klebsiella and Salmonella species respectively . The clinical courses and outcomes of the two patients (one survivor ) treated with retroperitoneal debridement and extra-anatomic bypass and a review of the modern surgical treatment are herein described.

FEMS Microbiol Lett, 1999 Apr 1, 173(1), 27 - 33
Genetic and biochemical characterization of an operon involved in the biosynthesis of 3-deoxy-D-manno-octulosonic acid in Pseudomonas aeruginosa; Walsh AG et al.; A Pseudomonas aeruginosa serotype O5 (PAO1) genomic DNA fragment that was able to complement a temperature-sensitive mutation in the 3-deoxy-D-manno-octulosonic acid (Kdo) 8-P synthase gene (kdsA) of Salmonella enterica serovar typhimurium was cloned . Nucleotide sequence analysis revealed the presence of a potential operon with the gene order pyrG, kdsA, eno . PyrG catalyzes the synthesis of the nucleotide cytidine triphosphate, while Eno catalyzes the formation of phosphoenolpyruvate from phosphoglycerate during glycolysis . Phosphoenolpyruvate is one of the substrates for Kdo-8-P biosynthesis by KdsA and cytidine triphosphate is the nucleotide used to activate Kdo prior to its transfer to lipid A . pyrG and eno are important for many metabolic pathways and it is interesting to find them linked to kdsA . A sigma 70-like promoter was found upstream of pyrG and evidence was provided to show that this promoter was responsible for the initiation of transcription of the genes in this operon . These genes mapped to 28.2-29.9 min on the 75-min PAO1 chromosome, unlinked to other lipopolysaccharide biosynthetic gene clusters.

Avian Dis, 1999 Jan-Mar, 43(1), 39 - 47
Evaluation of Salmonella serotype distributions from commercial broiler hatcheries and grower houses; Byrd JA et al.; By conventional trayliner (hatcheries) and drag swab assembly (broiler houses) culture methods, the isolation distribution of Salmonella serotypes from five commercial broiler hatcheries (three sample times) and 13 broiler farms (eight sample times) was evaluated . A total of 11 different Salmonella serotypes were isolated from hatcheries, with Salmonella heidelberg (9/30) and Salmonella kentucky (6/30) accounting for 50% of the total isolations . Of 700 chick paperpad trayliners sampled, regardless of lot (breeder flock source) or hatchery, 12% were positive for Salmonella . When 10 individual trayliners were cultured from individual lots (same breeder flock source), Salmonella was detected in 24/57 lots (42%) . Multiple serotypes were simultaneously isolated from the same lot on three occasions (6%) . Of the 21 lots that were serially sampled, the Salmonella serotype detected was different within lots eight times (38%) on at least one occasion of two or more sampling times . Of the 196 individual broiler houses sampled, 44 were positive for Salmonella (42%) . Twelve different serotypes were isolated from broiler houses during this study . The serotypes isolated most frequently were S . heidelberg (34/94) and S . kentucky (22/94) . These two serotypes accounted for 59.6% (56/94) of the total broiler house isolations . Of the 38 houses that were serially sampled, two or more serotypes were detected in the same broiler house on 20 occasions (53%) . Of the 38 serially sampled houses (four or more times), a consistent Salmonella serotype was detected in five houses (13%) . In only 5 of the 38 (13%) serially sampled houses did we fail to detect Salmonella on four or more samplings . No significant difference in Salmonella isolation frequency was observed between poultry houses using new or used litter . These data support previous findings indicating that paratyphoid Salmonella serotypes are prevalent in some broiler hatcheries and houses . Further, the observation of multiple serotypes simultaneously and serially isolated from the same breeder hatchery lots suggests that breeder flocks may be infected with more than one serotype, possibly providing a source for multiple serotype infections in progeny grower flocks.

Kansenshogaku Zasshi, 1999 Feb, 73(2), 110 - 21
{Bacteriological studies of traveller's diarrhoea (6) . Analysis of enteropathogenic bacteria at Kansai Airport Quarantine Station from September 4th, 1994 through December 1996}; Ueda Y et al.; During the period of investigation from Sept . 4, 1994 to Dec, 1996, a total of 11,446,534 overseas travellers were quarantined at Kansai Airport Quarantine Station, and 22,187 voluntarily reported of episodes suffering from diarrhoea . Bacteriological examination of the stools a total of 9,299 individuals' was performed, and the following results were obtained . 1) Various enteropathogenic bacteria were isolated from 33.3% of the stools examined . Bacterial species isolated were as follows: Plesiomonas shigelloides, 2,066 cases (66.7%); Vibrio parahaemolyticus, 358 cases (11.6%); Aeromonas sobria, 360 cases (11.6%); Shigella spp., 291 cases (9.4%); Salmonella spp., 183 cases (5.9%); A . hydrophila, 126 cases (4.1%); and V . cholerae non-O1, 121 cases (3.9%) . However, ETEC was not done with an object of test . 2) In 502 cases (16.2%), plural enteropathogenic bacteria were isolated from single patient, suggesting high frequency of a mixed infections . 3) From Feb . to Mar . 1995, thirteen cases cholera were found from patients who had travelled to Bali, Indonesia . Cases with enteropathogenic bacteria other than V . cholerae O1 were found without any seasonal variation . 4) The major regions where the travellers were infected with the pathogens are as follows: Vibrio spp., were from only Asia; Shigella, widely distributed but especially in India and Indonesia; P . shigelloides and Salmonella, widely distributed . 5) Among the Shigella strains, S . sonnei were isolated the most, followed by S . flexneri, S . boydii and S . dysenteriae . A strain of S . boydii provisional serovar E 16553 was isolated from a patient infected in India . 6) Among the Salmonella serovars, Salmonella Enteritidis was isolated the most frequently (49 cases, 25.7%) . 7) 265 (89.2%) of 297 Shigella strains, 52 (27.2%) of 19} Salmonella strains, and 19 (95.0%) of 20 V . cholerae O1 were resistant to one or more drugs tested (SM . CP . TC . KM . ABPC . NA . OFLX) . 8) All of the 20 V . cholerae O1 strains were Ogawa, E1 Tor . All of them were toxigenic strains . 9) The most frequently isolated serovar of V . parahaemolyticus was O3: K6 . 89.8% of all V . parahaemolyticus strains were positive for thermostable direct hemolysin (TDH) gene, and 14.6% of them were positive for TDH-related hemolysin (TRH) gene by DNA-probe or PCR method.

J Appl Microbiol, 1999 Apr, 86(4), 583 - 90
Development of a surface adhesion immunofluorescent technique for the rapid detection of Salmonella spp . from meat and poultry; Cloak OM et al.; A rapid method based on bacterial adhesion was developed for the detection of Salmonella in an enriched meat system . Minced beef samples inoculated with Salm . enteritidis (10 cfu g-1) were incubated overnight (18 h) at 37 degrees C in buffered peptone water . Salmonella enteritidis cells were isolated from the enriched meat sample by surface adhesion onto a polycarbonate membrane attached to a glass slide . The organisms attached to this polycarbonate membrane were subsequently visualized using immunofluorescent microscopy . The technique had a detection level of log10 3.5 Salmonella ml-1 . The surface adhesion immunofluorescent technique correlated well with Salmonella plate counts (r2 = 0.99) . Application of the rapid method to retail beef and poultry samples (n = 100) confirmed the correlation between this technique and traditional microbiological procedures . Thirty-one retail samples were reported positive for Salmonella species . No false positives or negatives were recorded for the rapid method.

Berl Munch Tierarztl Wochenschr, 1999 Mar, 112(3), 100 - 3
{Coupling of immunomagnetic separation and polymerase chain reaction for the rapid detection of salmonellae in minced meat and chicken giblets}; Erol I et al.; Coupling of immunomagnetic separation and polymerase chain reaction was used after preenrichment for the rapid detection of salmonellae in minced meat and chicken giblets . The primers used are specific to the origin of DNA replication (oriC) on the Salmonella chromosome and produce a 163 bp DNA fragment . The method allowed a screening of Salmonella free samples within 24 hours . It detected 5 serovars when inoculated in minced meat at a contamination level of 1 to 4 cfu/g . Compared with the method L 00.00-20 of the Official Collection of Methods of Analysis according to section 35 of the German Law on Food and Commodities it showed a sensitivity of 94% and a specificity of 87.5% for the examination of chicken giblets (n = 45) and a specificity of 100% for the examination of minced meat (n = 63).

Mol Microbiol, 1999 Mar, 31(6), 1695 - 707
Insertion of EspD into epithelial target cell membranes by infecting enteropathogenic Escherichia coli; Wachter C et al.; Diffusely adhering Escherichia coli (DAEC) strains have been implicated in epidemiological studies as a cause of diarrhoea in children . However, the molecular interactions of these pathogens with target cells have remained largely obscure . We found that some DAEC strains contain homologues of the locus of enterocyte effacement (LEE) pathogenicity island and secrete EspA, EspB and EspD proteins necessary for the formation of the attaching and effacing (A/E) lesions . To characterize the function of the EspD protein further, we cloned and sequenced the espD genes of two DA-EPEC strains and compared their deduced amino-acid sequences with known EspD sequences . A pattern of two conserved transmembrane regions and one conserved coiled-coil region is predicted in EspD and also in the type III system secreted proteins YopB, PopB, IpaB and SipB of Yersinia, Pseudomonas, Shigella and Salmonella respectively . The EspD protein is inserted into a trypsin-sensitive location in the HeLa cell membrane at sites of bacterial contact, but is not translocated into the cytoplasm . Secretion of EspD increases upon contact with host cells . We propose that the membrane-located EspD protein is part of the translocation apparatus for Esp proteins into the target host cell performing functions similar to YopB in Yersinia.

Acta Trop, 1999 Mar 15, 72(2), 175 - 83
Rapid and reliable serological diagnosis of enteric fever: comparative sensitivity and specificity of Typhidot and Typhidot-M tests in febrile Malaysian children; Choo KE et al.; The Typhidot test, which detects IgM and IgG antibodies to a Salmonella typhi-specific outer membrane protein, is as sensitive as, and more specific than, the Widal test in the diagnosis of enteric fever in Malaysian children . It is easier and quicker to perform . In order to increase diagnostic accuracy in an area of high endemicity, the Typhidot-M test has been developed in which IgG is first removed . This theoretically allows improved detection of IgM, and thus would differentiate new from recent infections . We evaluated both tests in 134 unselected febrile children admitted to the General Hospital Kota Bharu, Malaysia . The children were divided into two groups: (i) those who were blood and/or stool culture positive for S . typhi and/or who had clinical features strongly suggestive of enteric fever (n = 62); and (ii) those who were both culture-negative and had clinical evidence of another diagnosis (n = 72) . The sensitivity and specificity of the Typhidot and Typhidot-M tests were identical at 90.3 and 93.1%, respectively . Both tests had comparable sensitivity but greater specificity than those of the Widal test (91.9 and 80.6%, respectively) . When used together, a positive result for Typhidot and/or Typhidot-M was more specific than either test alone (95.2%) but specificity was lower (87.5%) . We conclude that the Typhidot and Typhidot-M tests have comparatively high diagnostic accuracy, suggesting that IgM can be detected in children who may have a predominant IgG response to S . typhi . Using these tests in combination increases the negative predictive value but at the cost of a lower positive predictive value.

Eur J Pharmacol, 1999 Mar 12, 369(1), 49 - 55
The lazaroid, U-74389G, inhibits inducible nitric oxide synthase activity, reverses vascular failure and protects against endotoxin shock; Altavilla D et al.; The aim of our study was to investigate the effect of the 21-aminosteroid U-74389G {21- < 4-(2,6-di-1-pyrrolidinyl-4-pyrimidinyl)-1-piperazinyl-pregna-1,4,9,(11) triene-3,20-dione(z)-2-butenedionate} on the l-arginine-nitric oxide (NO) pathway in a rat model of endotoxin shock . Endotoxin shock was produced in male rats by a single intravenous (i.v.) injection of 20 mg/kg of Salmonella Enteritidis lipopolysaccharide (LPS) . Rats were treated with U-74389G (7.5, 15 and 30 mg/kg i.v.) or vehicle (1 ml/kg i.v.) 5 min after endotoxin challenge . Lipopolysaccharide administration reduced survival rate (0%, 72 h after endotoxin administration) decreased mean arterial blood pressure, enhanced plasma concentration of bilirubin and alanine aminotransferase and increased plasma nitrite concentrations . Lipopolysaccharide injection also increased the activity of inducible NO synthase in the liver and in the aorta . Furthermore aortic rings from shocked rats showed a marked hyporeactivity to phenylephrine (1 nM-10 microM) . In addition lipopolysaccharide (50 microg/ml for 4 h) in vitro stimulation significantly increased nitrite production in peritoneal macrophages harvested from normal rats . Treatment with U-74389G (15 and 30 mg/kg i.v., 5 min after endotoxin challenge) significantly protected against lipopolysaccharide-induced lethality (90% survival rate 24 h and 80% 72 h after lipopolysaccharide injection, respectively, following the highest dose of the drug), reduced hypotension, ameliorated liver function, decreased plasma nitrite levels, restored the hyporeactivity of aortic rings to their control values and inhibited the activity of inducible NO synthase in the liver and in the aorta . Finally, U-74389G in vitro (12.5, 25 and 50 microM) significantly inhibited nitrite production in endotoxin stimulated peritoneal macrophages . The data suggest that U-74389G may exert beneficial effects in an experimental model of septic shock by inhibiting the activity of the inducible NO synthase.

Vet Rec, 1999 Mar 13, 144(11), 283 - 7
Salmonella pullorum in the common pheasant (Phasianus colchicus); Pennycott TW et al.; In 1996, pullorum disease due to Salmonella enterica serovar Gallinarum biovar pullorum (Salmonella pullorum) was diagnosed in pheasants on a gamebird rearing enterprise in south-west Scotland . The gross pathology and bacteriological findings are described, as are the results of screening for S pullorum on the site in 1997 . The causal organism was readily isolated from the lung, liver, yolk sac and heart blood on direct culture, but less readily from the digestive tract or by the use of selective media . The bacteria recovered from the pheasants were identified as S pullorum phage type 7, a phage type previously associated with pheasants rather than domestic fowl, and the organisms were most probably introduced to the site by the movement of carrier pheasants.

J Clin Microbiol, 1999 May, 37(5), 1348 - 51
Detection of multidrug-resistant Salmonella enterica serotype typhimurium DT104 based on a gene which confers cross-resistance to florfenicol and chloramphenicol; Bolton LF et al.; Salmonella enterica serotype typhimurium (S . typhimurium) DT104 (DT104) first emerged as a major pathogen in Europe and is characterized by its pentadrug-resistant pattern . It has also been associated with outbreaks in the United States . The organism typically carries resistance to ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline . The mechanism of chloramphenicol resistance in DT104 was determined by producing antibiotic-resistant Escherichia coli host strain clones from DT104 DNA . DNA from chloramphenicol-resistant clones was sequenced, and probes specific for the genes floS . typhimurium (floSt), int, invA, and spvC were produced for colony blot hybridizations . One hundred nine Salmonella isolates, including 44 multidrug-resistant DT104 isolates, were tested to evaluate the specificities of the probes . The gene floSt, reported in this study, confers chloramphenicol and florfenicol resistance on S . typhimurium DT104 . Florfenicol resistance is unique to S . typhimurium DT104 and multidrug-resistant S . typhimurium isolates with the same drug resistance profile among all isolates evaluated . Of 44 DT104 isolates tested, 98% were detected based on phenotypic florfenicol resistance and 100% had the floSt-positive genotype . Resistances to florfenicol and chloramphenicol are conferred by the gene floSt, described in this paper . Presumptive identification of S . typhimurium DT104 can be made rapidly based on the presence of the floSt gene or its resulting phenotype.

Proc Soc Exp Biol Med, 1999 Apr, 220(4), 239 - 43
Cancer chemopreventive mechanisms of tea against heterocyclic amine mutagens from cooked meat; Dashwood RH et al.; Cooking meat and fish under normal conditions produces heterocyclic amine mutagens, several of which have been shown to induce colon tumors in experimental animals . In our search for natural dietary components that might protect against these mutagens, it was found that green tea and black tea inhibit the formation of heterocyclic amine-induced colonic aberrant crypt foci (ACF) in the rat . Since ACF are considered to be putative preneoplastic lesions, we examined the inhibitory mechanisms of tea against the heterocyclic amines . In the initial studies using the Salmonella mutagenicity assay, green tea and black tea inhibited according to the concentration of tea leaves during brewing and the time of brewing; a 2-3-min brew of 5% green tea (w/v) was sufficient for >90% antimutagenic activity . N-hydroxylated heterocyclic amines, which are direct-acting mutagens in Salmonella, were inhibited by complete tea beverage and by individual components of tea, such as epigallocatechin-3-gallate (EGCG) . Inhibition did not involve enhanced mutagen degradation, and EGCG and other catechins complexed only weakly with the mutagens, suggesting electrophile scavenging as an alternative mechanism . Enzymes that contribute to the metabolic activation of heterocyclic amines, namely microsomal NADPH-cytochrome P450 reductase and N, O-acetyltransferase, were inhibited by tea in vitro . Studies in vivo established that tea also induces cytochromes P450 and Phase II enzymes in a manner consistent with the rapid metabolism and excretion of heterocyclic amines . Collectively, the results indicate that tea possesses anticarcinogenic activity in the colon, and this most likely involves multiple inhibitory mechanisms.

J Immunol, 1999 Apr 1, 162(7), 4220 - 5
Lipopolysaccharide-coated erythrocytes activate human neutrophils via CD14 while subsequent binding is through CD11b/CD18; Troelstra A et al.; Interaction of LPS with monocytes and neutrophils is known to occur via CD14 and is strongly enhanced by LPS-binding protein (LBP) . Integrins as well as CD14 play a role in the interaction of erythrocytes (E) coated with LPS or whole Gram-negative bacteria with phagocytes . We reasoned that the density of LPS on a particle is an important determinant in these interactions . Therefore, E were coated with different concentrations of LPS (ELPS) . The binding of these ELPS to neutrophils was evaluated by flow cytometry . Simultaneously, we measured fMLP receptor expression to evaluate neutrophil activation . ELPS only bound to neutrophils in the presence of LBP . Blocking CD14 inhibited both activation and binding, whereas blocking complement (C) receptor 3 (CR3) inhibited binding but not activation . TNF activation restored ELPS binding in CD14-blocked cells but not in cells in which CR3 was blocked . Salmonella minnesota did bind to neutrophils independent of CR3 or CD14 . The addition of LBP enhanced binding twofold, and this surplus was dependent upon CD14 but not on CR3 . We conclude that ELPS interact with neutrophils via CD14, initially giving rise to cell activation; subsequently, binding is solely mediated by activated CR3.

J Immunol, 1999 Apr 1, 162(7), 3830 - 9
Common intra-articular T cell expansions in patients with reactive arthritis: identical beta-chain junctional sequences and cytotoxicity toward HLA-B27; Dulphy N et al.; Spondyloarthropathies constitute a group of autoimmune diseases of special interest because of their tight association with the MHC class I molecule HLA-B27 and the bacterial triggering of some clinical forms called reactive arthritis (ReA) . One current hypothesis is the presentation by HLA-B27 of a so-called arthritogenic peptide to T cells . To better focus on the relevant T cell populations within the joint, we performed an extensive beta-chain T cell repertoire analysis of synovial fluid compared with PBL in seven patients, four of whom were characterized as having ReA triggered by Yersinia enterocolitica, Chlamydia trachomatis, or Shigella sonnei . Analysis of the size diversity of the beta-chain complementarity-determining region 3 (CDR3) allowed us to evaluate the degree of T cell clonality in the samples . Oligoclonal T cell expansions were frequently observed in the joint . In one patient, CDR3 amino acid sequences of major expansions using two different BV genes were identical . One dominant T cell expansion and several CDR3 amino acid sequences were identical in two different patients . Furthermore, one sequence was identical with a sequence reported independently in a Salmonella-induced ReA patient . Together, these data indicate a surprisingly high degree of conservation in the T cell responses in recent-onset ReA triggered by different micro-organisms . A CD8+ synovial line expressing shared clonotypes was established and reacted toward several B*2705 lymphoblastoid cell lines, therefore supporting a molecular mimicry phenomenon at the T cell level in the disease mechanism.

J Am Vet Med Assoc, 1999 Apr 1, 214(7), 1042 - 7
Comparison of medical and surgical treatment for impaction of the small colon in horses: 84 cases (1986-1996); Rhoads WS et al.; OBJECTIVE: To characterize clinical findings and compare effects of treatment and outcome for horses treated medically or surgically for impaction of the small colon . DESIGN: Retrospective study . ANIMALS: 84 horses with impaction of the small colon . PROCEDURE: Medical records were reviewed for history, physical examination findings, laboratory values, treatment, response to treatment, complications, out-come, and necropsy findings . RESULTS: 47 horses were treated medically and 37 horses were treated surgically . Significant differences between groups were not identified for duration of clinical signs, physical examination findings, or laboratory values . Horses treated surgically were hospitalized longer than horses treated medically . Complications recorded during hospitalization included diarrhea, jugular thrombophlebitis, recurrent colic, fever, and laminitis . Salmonella organisms were isolated from 20 horses . Horses treated surgically were more likely to have signs of moderate abdominal pain, gross abdominal distention, and positive results for culture of Salmonella spp than horses treated medically . Follow-up information was available for 27 horses treated medically and 23 horses treated surgically . Twenty-four (72%) and 21 (75%) of the horses, respectively, survived and were being used for their intended purpose at least 1 year after treatment . CLINICAL IMPLICATIONS: Colitis may be a predisposing factor for impaction of the small colon in horses . Prognosis for horses treated surgically or medically is fair.

J Bacteriol, 1999 Apr, 181(8), 2548 - 54
Accessory DNA in the genomes of representatives of the Escherichia coli reference collection; Hurtado A et al.; Different strains of the Escherichia coli reference collection (ECOR) differ widely in chromosomal size . To analyze the nature of the differential gene pool carried by different strains, we have followed an approach in which random amplified polymorphic DNA (RAPD) was used to generate several PCR fragments . Those present in some but not all the strains were screened by hybridization to assess their distribution throughout the ECOR collection . Thirteen fragments with various degrees of occurrence were sequenced . Three of them corresponded to RAPD markers of widespread distribution . Of these, two were housekeeping genes shown by hybridization to be present in all the E . coli strains and in Salmonella enterica LT2; the third fragment contained a paralogous copy of dnaK with widespread, but not global, distribution . The other 10 RAPD markers were found in only a few strains . However, hybridization results demonstrated that four of them were actually present in a large selection of the ECOR collection (between 42 and 97% of the strains); three of these fragments contained open reading frames associated with phages or plasmids known in E . coli K-12 . The remaining six fragments were present in only between one and four strains; of these, four fragments showed no similarity to any sequence in the databases, and the other two had low but significant similarity to a protein involved in the Klebsiella capsule synthesis and to RNA helicases of archaeal genomes, respectively . Their percent GC, dinucleotide content, and codon adaptation index suggested an exogenous origin by horizontal transfer . These results can be interpreted as reflecting the presence of a large pool of strain-specific genes, whose origin could be outside the species boundaries.

Vaccine, 1999 Mar 26, 17(13-14), 1667 - 73
The attenuated Salmonella vaccine approach for the control of Helicobacter pylori-related diseases; Gomez-Duarte OG et al.; The Gram-negative bacterium Helicobacter pylori is a widespread human pathogen that colonizes the gastric mucosa and is associated with gastro-intestinal illnesses such as gastritis, peptic ulcer, gastric lymphoma and gastric cancer . Current pharmacological therapies are becoming less reliable for the control of H . pylori due to the elevated costs and to the increasing number of antibiotic resistant strains . New vaccination strategies utilizing H . pylori antigens combined with adjuvants or delivery of antigens by attenuated Salmonella strains have been successful in protecting mice against H . pylori infections . Oral immunization with single doses of urease-expressing Salmonella vaccine strains elicits mucosal and systemic antibody responses and fully protects different mouse strains against challenge infections with H . pylori . The high efficacy in the mouse model, combined with remarkable immunogenicity, safety and low-cost production, makes attenuated live recombinant Salmonella promising vaccine candidates for the control of H . pylori-related diseases in humans.

Bioessays, 1999 Feb, 21(2), 99 - 104
Mosaic bacterial chromosomes: a challenge en route to a tree of genomes; Martin W; In a recent analysis J.G . Lawrence and H . Ochman {Proc Natl Acad Sci USA 1998;95:9413-9417 (Reference 1)} surmised that about 10% of the current E . coli genome consists of genes that were acquired in over 200 events of lateral gene transfer, which occurred subsequent to the divergence of E . coli and Salmonella some 100 million years ago . Overall, the data suggest that no less than 18% of E . coli's genes might be relatively recent foreign acquisitions, and that the average rate of acquisition may be close to about 16 kb per million years . These quantitative estimates of comparatively recent genome flux have profound impact on evolutionary genome comparisons . They tend to suggest that a search should be on to identify principles that might ultimately govern gene distribution patterns across prokaryotic genomes.

Gastroenterol Hepatol, 1999 Feb, 22(2), 79 - 81
{Spontaneous bacteremia due to Salmonella hadar in liver cirrhosis with transjugular intrahepatic portosystemic shunt}; Barrio J et al.; Bacteriemia is a frequent infection in patients with hepatic cirrhosis, which is associated with a high mortality . Spontaneous bacteriemia is generally caused by gramnegative bacilli . We present an episode of Salmonella hadar's spontaneous bacteriemia in a patient with cirrhosis of the liver and transjugular intrahepatic portosystemic shunt . The role of the prosthesis in the pathogenesis of bacteriemia in hepatic cirrhosis is discussed.

Berl Munch Tierarztl Wochenschr, 1999 Feb, 112(2), 41 - 3
Antibiotic resistance pattern of foodborne Salmonella isolates in Addis Ababa (Ethiopia); Molla B et al.; A total of 39 Salmonella cultures isolated from raw minced beef and chicken (gizzard, liver, and heart) samples in Addis Ababa were examined for susceptibility to a group of 10 selected antimicrobials . 34 isolates (87.2%) were resistant to one or more antibiotics . The antibiotics to which isolated Salmonella strains were most often fully resistant included nitrofurantoin (48.7%), furazolidone (48.7%) and streptomycin (46.2%) . Only 4 antimicrobials (gentamycin, kanamycin, rifampicin and sulphamethoxazole-trimethoprim) were effective against all Salmonella isolates with the exception of 2 which were intermediate in resistance to kanamycin (1) and sulphamethoxazole-trimethoprim (1) . 77.8% of the S . Enteritidis strains showed multiple resistance to up to four antibiotics followed by S . Typhimurium (60.0%) and S . Dublin (33.3%) . The high level of antibiotic resistance of foodborne Salmonella isolates in the study area is an indication of indiscriminate and continuous use of subtherapeutic doses of antibiotics in animals.

Vet Microbiol, 1999 Mar 12, 65(3), 227 - 31
Monophasic group B Salmonella species infecting harbour porpoises (Phocoena phocoena) inhabiting Scottish coastal waters; Foster G et al.; A monophasic strain of Salmonella group B having the antigenic structure 4, 12: a: - was isolated in culture from various tissues of 39 harbour porpoises (Phocoena phocoena) . The tissue from which the organism was recovered most frequently was lung in 33 animals and intestine in 16 animals, but it was also isolated from heart valve, liver, kidney, spleen, mesenteric lymph node, pulmonary lymph node, hepatic lymph node, urethra, sheath and epididymis . As far as we are aware this is the first record of this strain from an animal source, raising the possibility that it may be host-adapted to harbour porpoises . The possible modes of transmission of monophasic group B Salmonella between porpoises are discussed.

Appl Environ Microbiol, 1999 Apr, 65(4), 1610 - 8
Ferrioxamine-mediated Iron(III) utilization by Salmonella enterica; Kingsley RA et al.; Utilization of ferrioxamines as sole sources of iron distinguishes Salmonella enterica serotypes Typhimurium and Enteritidis from a number of related species, including Escherichia coli . Ferrioxamine supplements have therefore been used in preenrichment and selection media to increase the bacterial growth rate while selectivity is maintained . We characterized the determinants involved in utilization of ferrioxamines B, E, and G by S . enterica serotype Typhimurium by performing siderophore cross-feeding bioassays . Transport of all three ferric siderophores across the outer membrane was dependent on the FoxA receptor encoded by the Fur-repressible foxA gene . However, only the transport of ferrioxamine G was dependent on the energy-transducing protein TonB, since growth stimulation of a tonB strain by ferrioxamines B and E was observed, albeit at lower efficiencies than in the parental strain . Transport across the inner membrane was dependent on the periplasmic binding protein-dependent ABC transporter complex comprising FhuBCD, as has been reported for other hydroxamate siderophores of enteric bacteria . The distribution of the foxA gene in the genus Salmonella, as indicated by DNA hybridization studies and correlated with the ability to utilize ferrioxamine E, was restricted to subspecies I, II, and IIIb, and this gene was absent from subspecies IIIa, IV, VI, and VII (formerly subspecies IV) and Salmonella bongori (formerly subspecies V) . S . enterica serotype Typhimurium mutants with either a transposon insertion or a defined nonpolar frameshift (+2) mutation in the foxA gene were not able to utilize any of the three ferrioxamines tested . A strain carrying the nonpolar foxA mutation exhibited a significantly reduced ability to colonize rabbit ileal loops compared to the foxA+ parent . In addition, a foxA mutant was markedly attenuated in mice inoculated by either the intragastric or intravenous route . Mice inoculated with the foxA mutant were protected against subsequent challenge by the foxA+ parent strain.

Microbiol Immunol, 1999, 43(1), 69 - 71
Prolonged incubation period of salmonellosis in an outbreak of Salmonella enteritidis infection; Nagai K et al.; An outbreak of Salmonella enteritidis infections occurred in Otaru, Japan, in September 1997 . A total of 143 cases of salmonellosis were reported to the local Public Health Center . In this outbreak, one case had a 214-hr incubation period . We investigated 5 isolates including this case by phage typing and pulsed-field gel electrophoresis (PFGE) to determine the genetic heterogeneity of S . enteritidis . Five isolates were phage typed as reacted, but did not conform (RDNC) with identical reaction patterns and had quite similar PFGE patterns . Thus, the prolonged incubation period may not be attributed to genetic heterogeneity of the organism but rather to other factors.

Epidemiol Infect, 1999 Feb, 122(1), 103 - 10
Automated outbreak detection: a quantitative retrospective analysis; Stern L et al.; An automated early warning system has been developed and used for detecting clusters of human infection with enteric pathogens . The method used requires no specific disease modelling, and has the potential for extension to other epidemiological applications . A compound smoothing technique is used to determine baseline 'normal' incidence of disease from past data, and a warning threshold for current data is produced by combining a statistically determined increment from the baseline with a fixed minimum threshold . A retrospective study of salmonella infections over 3 years has been conducted . Over this period, the automated system achieved > 90% sensitivity, with a positive predictive value consistently > 50%, demonstrating the effectiveness of the combination of statistical and heuristic methods for cluster detection . We suggest that quantitative measurements are of considerable utility in evaluating the performance of such systems.

Epidemiol Infect, 1999 Feb, 122(1), 33 - 9
Molecular typing of Salmonella serotype Thompson strains isolated from human and animal sources; Chisholm SA et al.; One-hundred-and-thirteen isolates of Salmonella serotype Thompson from diverse sources in seven countries were characterized by PvuII ribotyping and IS200 fingerprinting . Ten PvuII ribotypes were observed . The predominant PvuII ribotype 1 represented a major clone of world-wide distribution but was not found in Australia; PvuII ribotypes 2 and 3 represented minor clones . HincII ribotyping discriminated subtypes within PvuII ribotype 1: HincII ribotype 1 was distributed widely but HincII ribotype 2 was found mainly in Scottish isolates . None of 101 isolates of PvuII ribotypes 1-3 contained copies of IS200 . All 12 isolates of PvuII ribotypes 4-10 were from Australia and 7 of them contained copies of IS200 of 5 different profiles . These results suggest the existence of at least two lineages of Salmonella Thompson with a different geographical distribution . The finding that most isolates from man and poultry in Scotland belonged to the same ribotype (PvuII 1/HincII 2) and were IS200-negative suggests that poultry is an important source of human infection in Scotland.

Epidemiol Infect, 1999 Feb, 122(1), 19 - 22
Phage type conversion in Salmonella enterica serotype Enteritidis caused by the introduction of a resistance plasmid of incompatibility group X (IncX); Brown DJ et al.; The plasmid pOG670, a 54 kb, conjugative plasmid that specifies resistance to ampicillin and kanamycin and belonging to the incompatibility group X (IncX), was transferred into 10 isolates of Salmonella enterica serotype Enteritidis belonging to 10 different phage types (PT1, 2, 3, 4, 8, 9, 9b, 10, 11 and 13) . Acquisition of the plasmid by these strains did not result in the loss of any resident plasmids but resulted in phage type conversion in 8 of the 10 strains (PT1, 2, 4, 8, 9, 9b, 10 and 11) . The observed changes in phage type were found to result from the loss of sensitivity to 3 of the 10 typing phages used (phages 3, 5 and 7) . Where the conversion resulted in a change to a defined phage type, both the new and original PTs belonged to the same, previously described, evolutionary lines . Enteritidis PTs 1, 4 and 8, commonly associated with poultry world-wide, were converted to PTs 21, 6 and 13a respectively . The results indicate a different route for phage type conversion Enteritidis from others reported in the literature and, although IncX plasmids are not normally present in PT8 or PT13a, may suggest a possible mechanism/link connecting these phage types.

J Bacteriol, 1999 Apr, 181(7), 2158 - 65
A periplasmic D-alanyl-D-alanine dipeptidase in the gram-negative bacterium Salmonella enterica; Hilbert F et al.; The VanX protein is a D-alanyl-D-alanine (D-Ala-D-Ala) dipeptidase essential for resistance to the glycopeptide antibiotic vancomycin . While this enzymatic activity has been typically associated with vancomycin- and teicoplainin-resistant enterococci, we now report the identification of a D-Ala-D-Ala dipeptidase in the gram-negative species Salmonella enterica . The Salmonella enzyme is only 36% identical to VanX but exhibits a similar substrate specificity: it hydrolyzes D-Ala-D-Ala, DL-Ala-DL-Phe, and D-Ala-Gly but not the tripeptides D-Ala-D-Ala-D-Ala and DL-Ala-DL-Lys-Gly or the dipeptides L-Ala-L-Ala, N-acetyl-D-Ala-D-Ala, and L-Leu-Pro . The Salmonella dipeptidase gene, designated pcgL, appears to have been acquired by horizontal gene transfer because pcgL-hybridizing sequences were not detected in related bacterial species and the G+C content of the pcgL-containing region (41%) is much lower than the overall G+C content of the Salmonella chromosome (52%) . In contrast to wild-type Salmonella, a pcgL mutant was unable to use D-Ala-D-Ala as a sole carbon source . The pcgL gene conferred D-Ala-D-Ala dipeptidase activity upon Escherichia coli K-12 but did not allow growth on D-Ala-D-Ala . The PcgL protein localizes to the periplasmic space of Salmonella, suggesting that this dipeptidase participates in peptidoglycan metabolism.

Pediatr Infect Dis J, 1999 Mar, 18(3), 245 - 8
A comparative study of ofloxacin and cefixime for treatment of typhoid fever in children . The Dong Nai Pediatric Center Typhoid Study Group; Cao XT et al.; BACKGROUND: Despite concerns about safety in children, fluoroquinolone antibiotics have become the treatment of choice in patients with multidrug-resistant typhoid fever in Vietnam . However, quinolone-resistant strains of Salmonella typhi have recently been reported from Vietnam; and if quinolone resistance becomes established, alternative oral treatment options will be needed . OBJECTIVE: Cefixime, an orally administered third generation cephalosporin, was compared with ofloxacin for the treatment of uncomplicated typhoid fever in children . METHODS: In an open trial children with suspected typhoid fever were randomized to receive either ofloxacin (10 mg/kg/day in two divided doses) for 5 days or cefixime (20 mg/kg/day in two divided doses) for 7 days . RESULTS: S . typhi was isolated from 82 patients (44 in the cefixime group, 38 in the ofloxacin group) and 70 (85%) of the isolates were multidrug-resistant . Median (95% confidence interval, range) fever clearance times were 4.4 (4 to 5.2, 0.2 to 9.9) days for ofloxacin recipients and 8.5 (4.2 to 9, 1.8 to 15.2) days for cefixime-treated patients (P < 0.0001) . There were 11 treatment failures (10 acute and one relapse) in the cefixime group and 1 acute treatment failure in the ofloxacin group (mean difference, 22%; 95% confidence interval, 9 to 36%) . CONCLUSION: Short course treatment with cefixime may provide a useful alternative treatment in cases of uncomplicated typhoid fever in children, but it is less effective than short course treatment with ofloxacin.

Oral Microbiol Immunol, 1998 Jun, 13(3), 150 - 7
Antigenic components of Actinobacillus actinomycetemcomitans lipopolysaccharide recognized by sera from patients with localized juvenile periodontitis; Gu K et al.; The dominant antigen of Actinobacillus actinomycetemcomitans recognized by high-titer sera from patients with localized juvenile periodontitis is the serotype antigen located in the O-side chains of lipopolysaccharide . Whether such sera contain antibodies reactive with other epitopes in lipopolysaccharide, as is the case for patients with rapidly progressive periodontitis, remains unknown . We prepared and characterized by gas liquid chromatography lipopolysaccharide, lipid A, core carbohydrate with no or few O-side chains (core) and high-molecular-mass carbohydrate-rich in O-side chains (oligosaccharide) from A . actinomyce-temcomitans ATCC 43718 (serotype b, Y4) . Using enzyme-linked immunosorbent assay (ELISA), sera from 36 patients with localized juvenile periodontitis were surveyed using whole-cell sonicate as plate antigen . The seven highest titer sera were selected for further study . Specific IgG antibody binding was observed to intact lipopolysaccharide and to all the lipopolysaccharide fractions . The mean titers were highest for intact lipopolysaccharide (138.8 ELISA units), and lipid A (122 ELISA units), followed by the core fraction (81 ELISA units) and the oligosaccharide fraction (69.5 ELISA units) . ELISA inhibition revealed that the core fraction at a concentration of 10 micrograms/test well inhibited antibody binding to A . actinomycetemcomitans lipopolysaccharide by a mean value of 56.7% . To further characterize antibody binding to the core fraction, ELISA inhibition was performed using as inhibitor the core carbohydrate fraction of the Re mutant of Salmonella minnesota, which is known to contain only alpha-keto-3-deoxyoctonate residues and phosphate . This fraction at 10 micrograms/test well inhibited binding of antibodies from 6 of 7 test sera with a mean value of 49.2% . Thus, sera from patients with localized juvenile periodontitis contain antibodies that bind to the O-side chains of lipopolysaccharide, as has been previously reported, but they also contain antibodies that bind to lipid A and to lipopolysaccharide core polysaccharide epitopes, specifically to alpha-keto-3-deoxyoctonate moieties . The humoral immune response to A . actinomycetemcomitans in patients with localized juvenile periodontitis is more complex than previously reported and is very similar to that of patients with rapidly progressive periodontitis.

Indian J Exp Biol, 1998 Dec, 36(12), 1245 - 52
Purification and characterization of phospholipase C of Salmonella gallinarum; Singh BR et al.; Phospholipase C was isolated from an outbreak strain of Salmonella gallinarum with ciprofloxacin extraction, dialysis, gel filtration, ion exchange chromatography and chromatofocussing . Purified phospholipase C (mol wt . 65 KDa; isoelectric point, pI 3.5) was resistant to pasteurization, stomach enzyme (pepsin), bacterial protease and lipase but lost its activity on trypsin and chymotrypsin treatment . It was sensitive to pH > or = 8.0 . It was haemolytic, embryotoxic, enterohaemorrhagic, lethal to birds, cytotoxic to Vero and MDBK cells, dermonecrotoxic in rabbit and antigenically active protein . Antisera raised against purified phospholipase C neutralized its all biological activities and agglutinated the producer Salmonella strains . Serologically it was proved similar to phospholipase C of Klebsiella pneumoniae and S . weltevreden . Fluorescent antibody technique (FAT) was standardized to detect phospholipase producer strains.

Indian J Exp Biol, 1998 Dec, 36(12), 1233 - 9
Role of bone marrow and thymus secretory protein in maintaining immune homeostasis and haemopoiesis in control and malnourished mice; Datta S et al.; Injection of Salmonella typhi 'H' antigen was observed to produce a differential effect on bone marrow and thymus secretory profile depending upon the nutritional status of the host . The paracrine effect of Thy F1 (thymus fraction 1) was more significant (P < 0.01) than the autocrine effect of BIM (Bone marrow immunomodulator) in malnourished mice . BIM moreover, also had a paracrine effect on thymus irrespective of the nutritional status of the host . An improvement in neutrophil population (P < 0.01) and phagocytic myeloperoxidase activity (P < 0.01) was observed in BIM treated malnourished immuno-suppressed mice, whereas no appreciable change was observed by Thy F1 . However, Thy F1 irrespective of the nutritional status of the host improved large lymphocyte population in circulation (P < 0.01) . These findings indicate that both bone marrow and thymus play a major role in haemopoietic microenvironment of BDF (basal diet fed) control and malnourished mice.

Int J Tuberc Lung Dis, 1999 Feb, 3(2), 169 - 73
Identification of Mycobacterium shimoidei by molecular techniques: case report and summary of the literature; Mayall B et al.; A 53-year-old woman from Melbourne, Australia, with squamous cell carcinoma of the oesophagus was shown by computed tomography (CT) scan to have a left apical cavity and inflammatory changes in the right lung consistent with aspiration . Acid-fast bacilli isolated from bronchial washings were identified biochemically first as Mycobacterium terrae, but later as M . shimoidei on the basis of 1) restriction fragment analysis and 2) sequencing of polymerase chain reaction (PCR) amplified 16S rDNA . Nine other descriptions of patients with M . shimoidei isolates were collated . The salient feature of isolates considered to be pathogenic was pulmonary cavitation . Most patients had underlying lung disease, including past tuberculosis or malignancy . Six of eight patients died of progressive respiratory illness, although the contribution of M . shimoidei was not always clear, and two patients improved . One patient with the acquired immune-deficiency syndrome (AIDS) died with Salmonella enteritidis and M . shimoidei isolated from blood cultures . One isolate was regarded as a coloniser . There are insufficient clinical or sensitivity data on which to base recommendations for therapy, but a combination of ethambutol, rifabutin and pyrazinamide could be considered.

Acta Crystallogr D Biol Crystallogr, 1999 Mar, 55 ( Pt 3), 706 - 8
Purification, crystallization and preliminary structural studies of dTDP-6-deoxy-D-xylo-4-hexulose 3,5-epimerase (RmlC), the third enzyme of the dTDP-L-rhamnose synthesis pathway, from Salmonella enterica serovar typhimurium; Giraud MF et al.; L-Rhamnose is an essential component of the cell wall of many pathogenic bacteria . Its precusor, dTDP-L-rhamnose, is synthesized from alpha-D-glucose-1-phosphate and dTTP via a pathway requiring four distinct enzymes: RmlA, RmlB, RmlC and RmlD . RmlC was overexpressed in Escherichia coli . The recombinant protein was purified by a two-step protocol involving anion-exchange and hydrophobic chromatography . Dynamic light-scattering experiments indicated that the recombinant protein is monodisperse . Crystals were obtained using the sitting-drop vapour-diffusion method with ammonium sulfate as precipitant . Diffraction data were collected on a frozen crystal to a resolution of 2.17 A . The crystal belongs to either space group P3121 or P3221, with unit-cell parameters a = b = 71.56, c = 183.53 A and alpha = beta = 90, gamma = 120 degrees.

J Infect, 1999 Jan, 38(1), 24 - 5
Convalescent excretion of Salmonella enteritidis in infants; Balfour AE et al.; OBJECTIVES: To review the excretion of Salmonella enteritidis PT4 in the faeces of infants involved in a point-source outbreak in a nursery, and to relate these findings to advice given by the Outbreak Control Team (OCT) . METHODS: Retrospective laboratory-based survey . RESULTS: Infection with S . enteritidis PT4 was microbiologically confirmed in 33 primary cases and one secondary case . Of the faeces submitted 4 weeks from exposure, 96% remained positive . None of the infants was symptomatic by this time, and none received antimicrobial treatment . Two infants aged less than 1 year were still excreting 22 weeks after the onset of the outbreak . CONCLUSIONS: As for other serotypes, S . enteritidis PT4 causes prolonged symptomless excretion after infection, particularly in infants aged less than 1 year . Infection control measures, including exclusion criteria, may need to be modified as an outbreak progresses.

J Food Prot, 1999 Mar, 62(3), 284 - 6
Broiler skin sampling for optimum recovery of Salmonella spp; Kotula KL et al.; The objective of this research was to determine the appropriate sample size (1, 5, or 10 g) and location (neck, breast, or vent) from which to sample processed poultry skin for Salmonella spp . Postkill, prescald broiler carcasses were used to help ensure that Salmonella spp . would be found . Mean Salmonella spp . counts from skin samples of 1 g (2.91 log10 CFU/g) were significantly lower (P < 0.05) than skin samples of 5 and 10 g: 3.52 log10 CFU/g and 3.42 log10 CFU/g, respectively . Mean Salmonella spp . counts from breast (3.62 log10 CFU/g) or neck (3.40 log10 CFU/g) skin samples were significantly higher (P < 0.05) than counts from vent skin samples (2.84 log10 CFU/g) . Neck skin is the preferred sampling location because it contained a representative number of Salmonella spp., it had a slightly higher incidence of Salmonella spp . than vent skin, and removal of neck skin for microbiological testing did not decrease the quality grade of the bird, as would the removal of breast skin . Research results will increase the accuracy and precision of the microbiological analytical procedures for processed poultry by providing guidelines for the amount and location of skin to be sampled, as well as the preparatory procedures involved to release the Salmonella spp . from the skin samples.

Zentralbl Veterinarmed B, 1999 Feb, 46(1), 9 - 23
Detection of antibodies to S . enteritidis in broilers by means of indirect ELISA and chemiluminescent immunoassay (CLIA); Zamora BM et al.; This study was conducted to develop a serological detection system for the monitoring of broiler flocks for Salmonella enteritidis infections . A specific S . enteritidis antigen (FG-Antigen) was used to compare the sensitivity and the specificity of the chemiluminescent immunoassay (CLIA) with those of the indirect ELISA . This comparison was performed using a total of 578 sera, which, depending on the microbiological and vaccination history, were categorized into groups . Most of the serum samples which were classified as positive showed higher titers in CLIA than in ELISA . Using the prevalence of positive reactors, significant differences between Groups were additionally demonstrated . The absorbance values of the passively immunized group showed the highest and those of the Salmonella-negative group the lowest correlation-coefficient . Using the mean net absorbance of the prevalence group, the ELISA system exhibited a sensitivity of 100% and a specificity of 96.2%, while CLIA had a sensitivity and a specificity of 85.7% and 96.2%, respectively . ELISA and CLIA can be used in the examination of non vaccinated flocks for S . enteritidis-infections as alternative to the bacteriological culture method . CLIA is distinguished for its fast and convenient procedure as well as for its wider measurement spectrum, while the indirect ELISA is almost as efficient as CLIA and requires less investment.

Berl Munch Tierarztl Wochenschr, 1997 Oct, 110(10), 373 - 7
{Efficacy of maternal Salmonella antibodies and experimental oral infection of chicks with Salmonella enteritidis}; Methner U et al.; Distribution of maternally transmitted Salmonella antibodies and their protective effects were studied in the progeny of broiler breeder birds which had been vaccinated with live S . Typhimurium and inactivated S . Enteritidis vaccines . Vaccination resulted in a significant increase of the antibody concentration in yolk of hatching eggs and in serum and jejunum of the progeny of immunized breeder birds . Higher antibody titres for isotypes IgG and IgA were still seen on day 21 of age . Antibody production of isotypes IgA and IgM by the chickens themselves was found between 14 and 21 days of age . Two challenge models (10(2) cfu/bird on day 1 of age and a seeder bird model, respectively) were used to evaluate the efficacy of maternal antibodies against challenge with S . Enteritidis . Using both models numbers of challenge organisms were lower in the caeca of the progeny of immunized parent birds between day 7 and day 21 of age (maximum about 1.5 log10 units) compared with control chicks . The results indicate the efficacy of maternally transferred antibodies but it remains the question of their practical relevance . The effects of acquired maternal antibodies on an active immunization of the progeny of immunized breeder birds with live Salmonella vaccines are discussed.

Berl Munch Tierarztl Wochenschr, 1997 Oct, 110(10), 369 - 72
{In vitro studies of adhesion and invasion by Salmonella strains of bovine epithelial cells}; Dinjus U et al.; 24 Salmonella strains were divided into three groups according to the circumstances of isolation . The adhesion and invasion abilities of the strains were determined using two permanent cell lines (IEC-6, VERO) and an epithelial cell line from the small intestine of a calf fetus (pKD) . Strains of different groups showed no differences in their ability to adhere to the cells tested . Significant differences were found for the invasion ability . Strains isolated from organs of calves suffering from salmonellosis showed a significant higher invasiveness for permanent cell lines and a considerable higher invasiveness for pKD cells than strains of the other groups.

Natl Med J India, 1998 Nov-Dec, 11(6), 266 - 7
Changing pattern of antibiotic sensitivity of Salmonella typhi; Ranju C et al.; BACKGROUND: The emergence of multidrug-resistant Salmonella typhi led to the use of quinolones as the first-line drug in the treatment of adult patients with typhoid fever . However, over the last few years there has been an impression that patients on ciprofloxacin tended to take longer to defervesce . We studied the response and antibiotic sensitivity patterns during 2 time periods to assess the changes that may have occurred . METHODS: A retrospective analysis was done of blood culture-positive patients with Salmonella typhi infection during 1991 and 1996-97 . The mode of presentation treatment history, antibiotic sensitivity pattern, antibiotics administered, response to therapy and the complications that ensued were studied . RESULTS: In vitro sensitivity to ciprofloxacin was found to be 100% in both the study groups . It was found that a greater number of patients were sensitive to ampicillin (80%), chloramphenicol (80%) and co-trimoxazole (80%) during 1996-97 as compared to 1991, when sensitivity to ampicillin was 63%, chloramphenicol 65% and co-trimoxazole 65% . The mean (SD) defervescence period in 1991 was 6 (2.3) days and in 1996-97 was 6 (2) days (p > 0.05) . CONCLUSION: In vitro sensitivity of Salmonella typhi to ciprofloxacin remains 100% . There was an increase in the sensitivity to ampicillin, chloramphenicol and co-trimoxazole which have been rarely used over the past few years . There was no significant difference in the time taken to defervesce between the two study periods.

Mutat Res, 1999 Mar 10, 425(1), 153 - 67
Thalidomide and metabolites: indications of the absence of 'genotoxic' carcinogenic potentials; Zhu X et al.; Because of the reintroduction into human therapeutics of thalidomide, a recognized developmental toxicant in humans, there has been concern about its potential for inducing other health effects as well . The present study is concerned with the possible mutagenicity and carcinogenicity of this chemical . Using the expert system, META, a series of putative metabolites of thalidomide was generated . In addition to the known or hypothesized metabolites of thalidomide (N=12), a number of additional putative metabolites (N=131) were identified by META . The structures of these chemicals were subjected to structure-activity analyses using predictive CASE/MULTICASE models of developmental toxicity, rodent carcinogenicity and mutagenicity in Salmonella . While thalidomide and some of its putative metabolites were predicted to be developmental toxicants, none of them were predicted to be rodent carcinogens . Putative metabolites containing the hydroxamic acid or hydroxylamine moieties were predicted to be mutagens . None of the 'known' metabolites of thalidomide contained these reactive moieties . Whether such intermediates are indeed generated or whether they are generated and are either unstable in the presence of oxygen or react rapidly with nucleophiles is unknown .

Mutat Res, 1999 Mar 10, 425(1), 29 - 46
Mutant yields and mutational spectra of the heterocyclic amines MeIQ and PhIP at the S1 locus of human-hamster AL cells with activation by chick embryo liver (CELC) co-cultures; Waldren CA et al.; Cooking meat and fish at high temperature creates heterocyclic amines (HA) including 2-amino-3,4-dimethylimidazo{4,5-f}quinoline (MeIQ) and 2-amino-1-methyl-6-phenylimidazo{4,5-b}pyridine (PhIP) . Several HA are mutagens in the Ames' S9/Salmonella assay . While PhIP is a substantial Ames' test mutagen, it is 1000-fold less active than the extraordinarily potent MeIQ . In contrast, MeIQ is significantly less mutagenic than PhIP in several mammalian cell assays, especially in repair-deficient Chinese hamster ovary (CHO) cells . HA are suspect human carcinogens on the basis of (i) epidemiological evidence, (ii) induction of tumors in rodents and monkeys, (iii) DNA adduct formation and (iv) mutagenic capacity . In this study, MeIQ and PhIP were significant mutagens at the S1 locus of co-cultivated human/hamster hybrid AL cells following metabolic activation by beta-napthoflavone (betaNF)-induced chick embryonic liver cultures (CELC) . MeIQ was more mutagenic than PhIP in the CELC+AL cell assay . The mutant response curves increase with dose and then plateau (PhIP), or decrease (MeIQ) . The inflections in these response curves coincide with dose-dependent decreases in cytochrome CYP1A1 activity . Molecular analysis of S1- mutants indicates that a substantial fraction, >65%, of the mutations induced by PhIP are deletions of 4.2 to 133 (Mbp); half are larger than 21 Mbp . Mutations induced by MeIQ were smaller, most (56%) being less than 5.7 Mbp . When appropriate metabolic activation is combined with a target locus, which can detect both small and large chromosomal mutations, both MeIQ and PhIP are significant mutagens and clastogens in repair proficient mammalian cells .

Vet Res, 1999 Jan-Feb, 30(1), 27 - 37
Technical and economic evaluation method for use in improving infectious animal disease surveillance networks; Dufour B; With hope of improving the increasing number of epidemiological surveillance networks for animal diseases set up in recent years, a qualitative and quantitative technical and economic evaluation tool was developed and then applied to three epidemiological surveillance networks: RENESA (a French surveillance network for salmonella and mycoplasma contamination in poultry production units subject to official sanitary controls), the French Foot and Mouth Disease Epidemiovigilance Network and REPIMAT (the epidemiological surveillance network in Chad for major cattle diseases) . We identified critical points in epidemiological surveillance networks using a modified version of the hazard analysis: critical control point (HACCP) method . An evaluation grid was then developed and validated by experts who were consulted in accordance with the Delphi method . A questionnaire to collect the information required for the evaluation and a scoring guide were then designed . Our evaluation procedure also included a calculation of the annual operating costs for two of the three networks studied . On the basis of the detailed results of the technical and economic evaluation, we formulated specific suggestions for improving the networks . The cost of implementing these proposals was calculated . We then simulated the effects of implementing each of the proposed improvements and a new global evaluation score was determined for each network . The 'cost per point' of each improvement was then calculated and discussed . This tool for the technical and economic evaluation of epidemiological surveillance networks for animal diseases is proposed so that it may be tested on a far wider scale and eventually be used in improving the functioning of such networks and for risk analysis in international trade.

Vet Microbiol, 1999 Mar 1, 65(2), 133 - 43
Enhancement of phagocytosis and bacterial killing by heterophils from neonatal chicks after administration of Salmonella enteritidis-immune lymphokines; Genovese LL et al.; During the first week post-hatch, chickens demonstrate an increased susceptibility to infection by bacteria such as Salmonella . The purpose of the present study was to evaluate the effects of immune lymphokines on phagocytosis and killing activities of heterophils in chicks during the first 1-7 days of life . Lymphokines isolated from chicken splenic T-cells harvested from Salmonella enteriditis (SE)-hyperimmunized hens (SE-ILK), have in past experiments, demonstrated augmentation of heterophil activity in day-of-hatch chicks resulting in protection from SE organ invasion . The present experiments reveal significant increases (p<0.05) in heterophil phagocytosis and killing when comparing chicks treated with SE-ILK to control groups in vitro . In SE-ILK-treated groups, a two-fold or greater increase is noted in heterophil phagocytosis within I h of incubation as compared to controls . Heterophils isolated from 1-day-old and 4-day-old chicks treated with SE-ILK killed significantly greater numbers (p<0.05) of SE than heterophils isolated from control groups . By Day 7 post-hatch, significance is not noted in the killing activity of heterophils from treated groups when compared to control groups . However, heterophils from SE-ILK groups continue to kill greater numbers of SE than control groups . These data support SE-ILK augmentation results in an enhanced heterophil function in chicks during the greatest period of susceptibility to Salmonella invasion.

Bull Soc Pathol Exot, 1998, 91(5 Pt 1-2), 456 - 60
{Traveller's diarrhea: which vaccines?}; Ivanoff B; Diarrheal diseases are a major cause of child morbidity and mortality, particularly in developing countries . It is estimated that diarrheal diseases and typhoid fever cause around 2.5 million deaths per year in the world . Four bacteria and one virus share this responsibility: Shigella spp, Escherichia coli ETEC, Vibrio cholerae, Salmonella typhi and rotavirus . People travelling in countries with high endemicity of diarrhoeal diseases risk facing these four bacteria or the less common rotavirus, which is usually active in infants, even though some cases of diarrhoea due to rotavirus have already been reported in adults . The usual recommendations concerning basic measures of hygiene are most of the time quickly forgotten and followed only by a small number of travellers (12) . Therefore, apart these useful recommendations, it is therefore necessary to consider complementary actions for controlling these diseases which are mainly transmitted by contaminated water and food . This article aims at giving an overview of currently available and future vaccines for preventing travellers' diarrheas.

Bull Soc Pathol Exot, 1998, 91(5 Pt 1-2), 402 - 5
{The role of bacterial diarrhea in developing countries}; Dosso M et al.; Bacterial diarrheas in developing countries remain a major public health problem . Cholera is endemo-endemic since 1970 . Clusters of Shigella infections are commonly observed during the rainy season . Other enteropathogen cause nosocomial infections and foodborne diseases . The HIV epidemic determined the emergence of a new trend of enteric diseases caused by opportunistic bacteria such as Salmonella Enteritidis, S . Typhimurium . The risk factors associated with these infections remains almost unknown . Treatment failure is related to an incre of high level resistance strains.

Vet Immunol Immunopathol, 1999 Feb 1, 67(2), 185 - 93
Secretion of Salmonella-specific antibodies in the oviducts of hens experimentally infected with Salmonella enteritidis; Withanage GS et al.; The production and secretion of Salmonella enteritidis whole cell antigen-specific antibodies in the oviducts and in the serum of laying hens experimentally infected with Salmonella enteritidis, was analyzed by ELISA . The dynamics of the antibody levels in the oviducts were identical to that in the serum . Subclasses of antibodies (IgA, IgG, and IgM) in the infected hens were found to increase significantly (p < 0.01) compared to those in the control uninfected hens throughout the experiment . IgG and IgM levels in both oviducts and in sera reached to a peak by 14 days post-inoculation, and remained elevated throughout . The secretion of IgA seemed to be transient since the IgA levels increased to a peak 7 days after both primary and secondary inoculations, and declined rapidly . The elevated levels of antibodies were followed by partial clearance of Salmonella organisms from the oviducts . The present results indicate a significant local immune reaction against the Salmonella infection and suggest an association of the local antibodies with the clearance of Salmonella from the oviducts at least partially.

FEMS Immunol Med Microbiol, 1999 Feb, 23(2), 165 - 73
Live antigen carriers as tools for improved anti-tuberculosis vaccines; Hess J et al.; Recombinant (r) Mycobacterium bovis BCG strains have been constructed which secrete biologically active listeriolysin (Hly) fusion protein of Listeria monocytogenes . In human and murine macrophage-like cell lines, intracellular persistence of these r-BCG strains was reduced as compared to the parental BCG strain . By immunogold labelling Hly was detected in membrane structures and within the phagosomal space of macrophages . Hly fusions consistently co-localized with a lysosome-associated membrane glycoprotein (LAMP-1) suggesting that membrane attack conformation of Hly was not altered . Although r-BCG microorganisms apparently did not egress into the cytoplasmic compartment of host cells, they both improved major histocompatibility complex class I presentation of co-phagocytosed soluble ovalbumin as compared with wild-type BCG microbes . These data suggest that Hly secretion endows BCG with an improved capacity to stimulate CD8 T cells . Because CD8 T cells play a major role in protection against tuberculosis such Hly-secreting r-BCG constructs are anti-tuberculosis vaccine candidates . In addition, we report on our r-Salmonella typhimurium expression system combined with the HlyB/HlyD/ TolC export machinery for delivering the prominent mycobacterial antigen Ag85B for immune recognition.

J Microbiol Methods, 1999 Feb, 35(1), 77 - 84
A PCR-based strategy for simple and rapid identification of rough presumptive Salmonella isolates; Hoorfar J et al.; The purpose of the present study was to investigate the application of ready-to-go Salmonella PCR tests, based on dry chemistry, for final identification of rough presumptive Salmonella isolates . The results were compared with two different biotyping methods performed at two different laboratories . The sensitivity of the BAX Salmonella PCR test was assessed by testing a total of 80 Salmonella isolates, covering most serogroups, which correctly identified all the Salmonella strains by resulting in one 800-bp band in the sample tubes . The specificity of the PCR was assessed using 20 non-Salmonella strains, which did not result in any DNA band . A total of 32 out of the 36 rough presumptive isolates were positive in the PCR . All but one isolate were also identified as Salmonella by the two biochemical methods . All 80 Salmonella strains were also tested in the two multiplex serogroup tests based on PCR beads . All strains belonging to the serogroups B, C1, C2-C3, and D were grouped correctly . Among the 32 rough presumptive isolates identified, 19 isolates resulted in a band of 882 bp (serogroup B), 11 isolates resulted in a band of 471 bp (serogroup C1), and two isolates showed a band of 720 bp (serogroup D) . In conclusion, rough presumptive Salmonella isolates can be conveniently confirmed to the serogroup-level, using the pre-mixed PCR tests . The system can be easily implemented in accredited laboratories with limited experience in molecular biology.

JAMA, 1999 Mar 3, 281(9), 811 - 7
Epidemiology, etiology, and impact of traveler's diarrhea in Jamaica; Steffen R et al.; CONTEXT: Traveler's diarrhea (TD) can incapacitate travelers . Characteristics of TD could be helpful in identifying individuals who might benefit from a vaccine against TD . OBJECTIVE: To determine epidemiology, etiology, and impact of TD in Jamaica . Design Two-armed, cross-sectional survey conducted between March 1996 and May 1997 . SETTING: Sangster International Airport and 10 hotels in Montego Bay area, Jamaica . SUBJECTS: To investigate epidemiology and impact, 30369 short-term visitors completed a questionnaire just before boarding their homebound aircrafts . To investigate etiology, 322 patients (hotel guests) with TD provided stool samples . MAIN OUTCOME MEASURES: Attack and incidence rates of reported diarrhea and of classically defined TD (> or =3 unformed stool samples in 24 hours and > or =1 accompanying symptom), incapacity, risk factors, and etiology . RESULTS: The attack rate for diarrhea was 23.6% overall, with 11.7% having classically defined TD . For a mean duration of stay of 4 to 7 days, the incidence rate was 20.9% (all TD) and 10.0% (classic TD) . Among airport respondents, the incapacity lasted a mean of 11.6 hours . Less than 3% of all travelers avoided potentially high-risk food and beverages . The most frequently detected pathogens were enterotoxigenic Escherichia coli, Rotavirus, and Salmonella species . CONCLUSIONS: A realistic plan for reducing TD is needed . Preventive measures such as the improvement of hygienic conditions at the destination, and/or the development of vaccines against the most frequent pathogens associated with TD may contribute toward achieving this goal.

Nephrol Dial Transplant, 1999 Feb, 14(2), 353 - 9
Decreased IgA1 response after primary oral immunization with live typhoid vaccine in primary IgA nephropathy; Roodnat JI et al.; INTRODUCTION: Patients with primary IgA nephropathy (IgAN) have an increased level of immunological memory to certain parenteral recall antigens . We recently found a deficient IgA1 immune response after intranasal challenge with a neo-antigen: cholera toxin subunit B . In the present study, we assessed the specific IgA1 and IgA2 antibody response in plasma, peripheral blood cells and mucosal secretions after primary enteral immunization . METHODS: Twenty eight IgAN patients, 26 patients with non-immunological renal disease and 32 healthy subjects were immunized orally with three sequential doses of live, attenuated, Salmonella typhi Ty21a . The humoral immune response in body fluids and antibody synthesis by circulating B cells was assessed in specific ELISAs and ELIPSAs respectively . RESULTS: Oral immunization resulted in significantly (P<0.0001) increased IgM, IgG, IgA, IgA1 and IgA2 responses in all groups, both in plasma and in circulating B cells in vitro . The IgA1 response in plasma was significantly (P<0.05) lower in IgAN patients, while no significant differences in IgM (P=0.36), IgG (P= 0.79) or IgA2 (P=0.45) responses were found as compared with matched control groups . The amount of IgA1 synthesized by circulating B cells tended to be lower in IgAN patients . No significant IgA response after oral immunization with S . typhi Ty21a was found in saliva (P=0.11) or tears (P=0.10) . CONCLUSIONS: These data suggest an IgA1 hyporesponsiveness in patients with IgAN that is not only apparent after primary challenge of the nasal-associated lymphoid tissue but also after presentation to the gut . Previous results after parenteral recall immunization may be explained by assuming that IgAN patients require more frequent and/or longer exposure to IgA1-inducing antigens on their mucosal surfaces before they reach protective mucosal immunity . As a consequence, overproduction of IgA1 antibodies occurs in the systemic compartment, accompanied by an increased number of IgA1 memory cells.

Enferm Infecc Microbiol Clin, 1999 Jan, 17(1), 9 - 14
{Distribution of Salmonella spp . serotypes isolated in Spain during a 4-year period (1993-1996)}; Echeita MA et al.; BACKGROUND: Knowledge of the epidemiology of salmonellosis over time is the main tool for public health care control of this disease which is the main cause of alimentary toxic infections in Spain . The epidemiologic marker of choice in this genus is the stable, simple technique of serotyping, which, given its wide use allows the follow up of the main serotypes over the years . This study analyzes the seasonal trends of the main serotypes of Salmonella received in the National Reference Laboratory of Salmonella and Shigella in Spain (LNRSSE) from 1993-1996 . MATERIALS AND METHODS: Serotyping of the strains of Salmonella received in the LNRSSE during the years of the study with sera induced in our laboratory and commercial laboratories was undertaken . The strains of human origin the trends of the main serotypes were evaluated with the Mantel-Haenszel chi 2 test . RESULTS AND DISCUSSION: Nineteen thousand seven hundred forty-one strains of Salmonella from most of the autonomous communities of Spain were analyzed . Ninety-two point one two percent of the strains of human origin were received from laboratories that sent strains throughout at least three of the four years of the study, thereby allowing evaluation of the serotype trends for this group of strains . The enteritidis and typhimurium serotypes were the most frequently observed . In these serotypes the strains of human origin were typed with double the frequency of that found among those from food and three-fold greater than that found among the strains of environmental origin . Typhimurium was the more frequently found than enteriditis in the group of strains from diseased animals . Finally, the significant statistical increase of the hadar serotype, which surpassed the virchow serotype in recent years, is of note.

Vaccine, 1999 Feb 26, 17(7-8), 770 - 8
Expression of a pilin subunit BfpA of the bundle-forming pilus of enteropathogenic Escherichia coli in an aroA live salmonella vaccine strain; Schriefer A et al.; Enteropathogenic Escherichia coli (EPEC) is a major cause of childhood diarrhea in developing countries and is a leading cause of severe diarrheal illness among Brazilian infants . As one approach to constructing a vaccine candidate against diarrhea caused by EPEC, we evaluated whether the pilin subunit (BfpA) of the bundle-forming pilus (BFP) could be expressed by a live Salmonella vaccine strain . Several copies of the coding region of BfpA (bfpA) were amplified by PCR from a preparation of the EAF plasmid of EPEC strain B171 and cloned into plasmid vectors . An intact copy of bfpA was subcloned into the heat inducible prokaryotic expression vector pCYTEXP1, and the resulting pBfpA was used to transform the aroA S . typhimurium strain SL3261, generating SL3261(pBfpA) . The recombinant vaccine strain was able to express, but not to process, rBfpA as evidenced by a prominent 21 kDa protein that crossreacted with anti-BFP antiserum found only in extracts of heat-treated SL3261(pBfpA), but not in strains of untreated SL3261(pBfpA) or SL3261 not carrying the plasmid . Furthermore, rBfpA accumulation was not toxic to the Salmonella host, as evidenced by similar plating efficiencies between induced and uninduced strains of SL3261(pBfpA) . Finally, SL3261(pBfpA) orally administered to BALB/c mice was capable of eliciting a sustained and vigorous humoral immune response to BfpA, achievable even with a single oral dose of approximately 10(9) organisms . Therefore, this pilin product may serve as a potential immunogen as part of a live combined vaccine strategy to prevent two of the major public health problems in Brazil--salmonellosis and EPEC childhood diahrrea.

Immunol Lett, 1999 Jan, 65(1-2), 81 - 4
Impact of intracellular location of and antigen display by intracellular bacteria: implications for vaccine development; Kaufmann SH et al.; Intracellular bacteria are primarily controlled by T-lymphocytes . The 'phagosomal' bacteria such as Salmonella enterica and Mycobacterium bovis BCG remain in the phagosome . These microbes primarily stimulate CD4 T-cells via antigen presentation through MHC class II molecules . In contrast, Listeria monocytogenes egresses from the phagosome into the cytoplasm by virtue of listeriolysin . This 'cytoplasmic' pathogen is controlled by CD8 T-cells through MHC class I antigen presentation . Some bacterial pathogens such as Mycobacterium tuberculosis presumably remain in the phagosome but apparently 'perforate' the phagosomal membrane and thus stimulate both CD4 and CD8 T-cells . We have constructed S . enterica and M . bovis BCG vaccine carriers which secrete listeriolysin . Such constructs are capable of introducing antigens into the MHC class II and MHC class I pathway, resulting in stimulation of both CD4 and CD8 T-cells . Moreover, we constructed S . enterica vaccines which display one and the same listerial antigen in secreted and somatic form . Secreted antigen display was found to be superior to somatic antigen display . Hence, we consider antigen secretion a major prerequisite of an effective vaccine against intracellular bacteria.

Eur J Clin Microbiol Infect Dis, 1998 Dec, 17(12), 880 - 3
High rates of antimicrobial resistance among clinical isolates of nontyphoidal Salmonella in Taiwan; Yang YJ et al.; To assess trends in antimicrobial-resistant Salmonella infections from 1989 to 1996 in southern Taiwan, the minimum inhibitory concentrations (MICs) of 14 antibiotics or antibiotic combinations were determined by the agar dilution method for 297 clinical isolates of nontyphoidal Salmonella . The rates of resistance to ampicillin, chloramphenicol, and tetracycline were 65, 67, and 78%, respectively . Resistance to trimethoprim-sulfamethoxazole (TMP-SMX) increased from 25% in 1989-1992 to 35% in 1993-1996 (P=0.057) . For new quinolones and extended-spectrum cephalosporins, no resistant strains were encountered . Multiple resistance to more than five antimicrobial drugs doubled from 10.6% in 1989-1992 to 19.7% in 1993-1996 . Multiply resistant salmonellae were isolated more commonly from blood samples than from feces (30% vs . 14%, P<0.05) . In Taiwan, ampicillin, chloramphenicol, and even TMP-SMX are no longer the drugs of choice for treatment of serious nontyphoidal Salmonella infections . Extended-spectrum cephalosporins are now the preferred drugs in Taiwan for treatment of invasive Salmonella infections in children.

Indian Heart J, 1998 Sep-Oct, 50(5), 516 - 9
Clinical spectrum of infective endocarditis: 15 years experience; Jalal S et al.; Four hundred and sixty-six patients (277 males, 189 females; mean age 23.2 years) diagnosed as cases of infective endocarditis during the past 15 years were retrospectively analysed . Two-thirds of patients belonged to the 15 to 35 years age group . The most common predisposing cardiac lesion was rheumatic heart disease seen in 73.4 percent patients . Mitral valve prolapse and right-sided endocarditis were infrequent, seen in four patients each . Blood culture positivity was 28.7 percent in adults and 61 percent in children . Commonest organism isolated was staphylococcus aureus in adults (39.3%) and streptococcus viridans in children (48%) . Salmonella typhi was detected in 17 patients and showed excellent response to ciprofloxacin and gentamycin . Overall mortality was 13.9 percent and resistant heart failure was the leading cause of death . Our study presents the clinical spectrum of infective endocarditis and highlights the comparison with western studies.

Gastroenterol Clin Biol, 1998 Dec, 22(12), 1102 - 5
{Calcified splenic abscess, colonic fistula and ascites in a chronic carrier of Salmonella typhi}; Debat Zoguereh D et al.; We report the unusual case of a patient with chronic carriage of Salmonella typhi who presented with partially calcified splenic abscess linked to colic fistula and ascitis . The colic fistula could be secondary to ischemic necrosis by left colon compression due to spleen large abscess . Fistula was evidenced by abdominal computed tomography scan and confirmed by barium enema . The possible etiologies of ascitis are either tuberculosis or ascitic peritonitis secondary to the fistulisation; nevertheless, the role of segmentary portal located hypertension cannot be completely excluded . The splenic abscess was probably due to Salmonella typhi which was only isolated from stool specimens . The calcified splenic abscess was the evidence that the infection had occurred first . In addition, the isolation of Salmonella typhi in stool cultures six months after the subject had returned from the Comores proved the chronic carriage . Treatment by splenectomy and left colectomy was successful in this patient.

Proc Natl Acad Sci U S A, 1999 Mar 2, 96(5), 2396 - 401
The Salmonella invasin SipB induces macrophage apoptosis by binding to caspase-1; Hersh D et al.; Recently, Salmonella spp . were shown to induce apoptosis in infected macrophages . The mechanism responsible for this process is unknown . In this report, we establish that the Inv-Spa type III secretion apparatus target invasin SipB is necessary and sufficient for the induction of apoptosis . Purified SipB microinjected into macrophages led to cell death . Binding studies show that SipB associates with the proapoptotic protease caspase-1 . This interaction results in the activation of caspase-1, as seen in its proteolytic maturation and the processing of its substrate interleukin-1beta . Caspase-1 activity is essential for the cytotoxicity . Functional inhibition of caspase-1 activity by acetyl-Tyr-Val-Ala-Asp-chloromethyl ketone blocks macrophage cytotoxicity, and macrophages lacking caspase-1 are not susceptible to Salmonella-induced apoptosis . Taken together, the data demonstrate that SipB functions as an analog of the Shigella invasin IpaB.

Intensive Care Med, 1999 Jan, 25(1), 52 - 7
Endotoxin inhibits heat shock protein 70 (HSP70) expression in peripheral blood mononuclear cells of patients with severe sepsis; Schroeder S et al.; OBJECTIVE: To investigate the ex vivo endotoxin-inducible heat shock protein 70 (HSP70) expression in the peripheral blood mononuclear cells (PBMC) of patients with severe sepsis in order to assess the capacity of this potentially protective response during systemic inflammation . DESIGN: Prospective observational study in consecutive patients with severe sepsis and healthy blood donors . SETTING: Surgical intensive care unit in a university hospital . PATIENTS AND PARTICIPANTS: Eleven patients with the diagnosis of severe sepsis, one patient who had recovered from severe sepsis and 13 healthy blood donors . INTERVENTIONS: None . MEASUREMENTS AND RESULTS: We studied the inducibility of HSP70 expression in the PBMC of patients with severe sepsis and healthy blood donors ex vivo . Human whole blood was incubated with variable lipopolysaccharide (LPS from Salmonella minnesota Re 595) concentrations (0; 0.1; 10; 100 ng/ml) for different periods of time (0.5; 2; 4; 10 h) . The PBMC were separated by Ficoll density gradient and then disrupted by hypotonic lysis . HSP70 was measured by means of enzyme-linked immunosorbent assay (ELISA) . We found a LPS dose- and time-dependent inhibition of ex vivo HSP70 expression in the PBMC of both patients with severe sepsis and healthy individuals . However, the levels of HSP70 expression in patients were significantly lower compared to those of healthy individuals at all LPS concentrations and incubation times . On average, HSP70 expression in the PBMC of healthy controls was 2.8 (range 1.2-3.9) times higher than in patients . HSP70 expression was inducible by thermal heat shock in the PBMC of both patients and healthy individuals . CONCLUSIONS: Endotoxin inhibits HSP70 expression in PBMC ex vivo . In vivo, the suppression of HSP70 expression induced by endotoxin and high levels of proinflammatory cytokines may contribute to the cellular dysfunction of immunocompetent cells concerning antigen presentation, phagocytosis and antibody production associated with decreased resistance to infectious insults during severe sepsis.

Poult Sci, 1999 Feb, 78(2), 211 - 4
Effect of lactose administration in drinking water prior to and during feed withdrawal on Salmonella recovery from broiler crops and ceca; Barnhart ET et al.; Salmonella contamination of the chicken crop has been reported to increase markedly and significantly during feed withdrawal, probably due to coprophagy, and may contribute to carcass contamination at processing . The effect of prolonged lactose administration (2.5%) in the drinking water on the incidence of Salmonella recovery from broiler crops or ceca was evaluated in seven experiments . In these experiments, all or a percentage (providing seeders and contacts) of 7-wk-old broilers were challenged with approximately 1 x 108 cfu Salmonella enteritidis and provided lactose for 5 or 11 d prior to and during an 18 or 24 h feed withdrawal period . A small but significant lactose-mediated reduction in Salmonella contamination of crops was observed in one of two identical experiments with 18 h feed withdrawal . Extending the feed withdrawal period to 24 h did not improve the ability of lactose to affect Salmonella recovery from crops or ceca . Similarly, lactose did not affect Salmonella recovery when the percentage of birds challenged was reduced to 3 out of 16 and Salmonella recovery from crops or ceca of unchallenged, contact broilers was measured . Extending the duration of exposure to 2.5% lactose in the drinking water from 5 to 11 d did not improve the ability of lactose to affect Salmonella recovery . Taken together, these data suggest that provision of 2.5% lactose in the drinking water during the last 5 to 11 d of growout prior to slaughter will not be useful in an integrated Salmonella control program under commercial conditions.

Int J Food Microbiol, 1999 Jan 12, 46(1), 37 - 44
Rapid detection of stressed Salmonella spp . in dairy and egg products using immunomagnetic separation and PCR; Rijpens N et al.; The rapid detection of an average of 5.9 stressed Salmonella cells in 25 g of food product using immunomagnetic separation (IMS) and PCR is described . For pasteurised egg yolk, egg yolk powder, ice-cream, whole egg, egg white and cheeses made from pasteurised milk PCR was applied after 16 h of preenrichment in buffered peptone water (BPW) using IMS and alkaline lysis as sample preparation method . For whole egg and egg white the BPW was supplemented with iron . For milk powder, and raw milk cheeses, the 16-h preenrichment in BPW was followed by IMS and a 4-h enrichment in Rappaport-Vassiliadis broth . In the latter case, PCR was applied on the enrichment medium after centrifugation and alkaline lysis . For PCR the primers ST11 and ST15 (Aabo et al., 1993) producing a fragment of 429 bp were used . An internal PCR control, designed to be co-amplified with the target DNA using the same primers but producing a smaller fragment of 240 bp, was used.

Asia Pac J Public Health, 1996-97, 9, 1 - 5
Salmonella serotypes isolated in Malaysia over the ten-year period 1983-1992; Yasin RM et al.; From January 1983 to December 1992 a total of 20,874 salmonella were serotyped in the Bacteriology Division IMR, which showed an increase of 100% compared to the previous ten-years . There were 97 serotypes which belonged to 22 Kauffmann-white groups . Twenty two serotypes hitherto were seen in this study period . S . typhi was the commonest serotype isolated . Overall there was a rise in the isolation of non-typhoidal salmonella particularly S . enteritidis which increased by 760% and S . blockley which increased by 720% . However there is a drop in the isolation of S typhimurium by 223% and S . paratyphi B by 319%.

Appl Environ Microbiol, 1999 Mar, 65(3), 1312 - 5
Pulsed-light inactivation of food-related microorganisms; Rowan NJ et al.; The effects of high-intensity pulsed-light emissions of high or low UV content on the survival of predetermined populations of Listeria monocytogenes, Escherichia coli, Salmonella enteritidis, Pseudomonas aeruginosa, Bacillus cereus, and Staphylococcus aureus were investigated . Bacterial cultures were seeded separately on the surface of tryptone soya-yeast extract agar and were reduced by up to 2 or 6 log10 orders with 200 light pulses (pulse duration, approximately 100 ns) of low or high UV content, respectively (P < 0.001).

Appl Environ Microbiol, 1999 Mar, 65(3), 1055 - 60
Sensitivity, specificity, and predictive values of three Salmonella rapid detection kits using fresh and frozen poultry environmental samples versus those of standard plating; Peplow MO et al.; To reduce human exposure to Salmonella spp . in poultry products, broiler chicken flocks have been tested by culture methods . Since the standard techniques may take 3 to 5 days, rapid detection methods have been developed . In this study we tested the performance of three rapid tests originally developed for food samples by using environmental samples obtained from poultry houses . These rapid tests were Reveal, an enzyme-linked immunosorbent assay from Neogen Corp.; BIND, a bacterial ice nucleation detection method from Idetek Corp.; and a filter monitor method from Future Medical Technologies, Inc . For the standard culture, brilliant green with novabiocin and xylose-lysine-tergitol-4 agar were used for presumptive identification, and identities were confirmed by using poly-O antisera . Environmental samples were collected from farms belonging to an integrated poultry company prior to chick placement and 1 week before slaughter . Sensitivities, specificities, and predictive values with 95% confidence intervals were calculated . Statistical differences were determined by using McNemar's chi square test . The sensitivities of the different tests were not stable, varying widely between sample times, and were affected by freezing of the samples . All of the rapid tests had low sensitivities, which led to many false-negative results . All tests were able to detect Salmonella spp . at a concentration of 10 CFU/ml in at least one of four trials . The BIND and Reveal tests were simple to use with multiple samples and reduced laboratory time by up to 1 day . Based on our results, we do not recommend that any of these rapid tests, in their present state of development, be utilized with environmental samples collected with drag swabs.

Regul Toxicol Pharmacol, 1998 Dec, 28(3), 199 - 211
Regulatory action criteria for filth and other extraneous materials . III . Review of flies and foodborne enteric disease; Olsen AR; Forty-seven species of flies have been reliably associated with filthy conditions that might allow the spread of foodborne pathogens . These are categorized as "filth flies." Of that 47, only 21 species represent a potential threat to human health as scientifically proven causative agents of foodborne myiasis or as carriers of enteropathogenic Escherichia coli, Salmonella, Shigella, and other foodborne pathogens . These 21 species are categorized as "disease-causing flies" based on strict scientific criteria . The criteria are association with E . coli, Salmonella, AND Shigella; synanthropy; endophily; communicative behavior; attraction to both excrement and food products; and recognition by authorities as a potential health hazard . Within Hazard Analysis and Critical Control Point and other U.S . Food and Drug Administration regulatory frameworks, disease-causing flies are contributing factors to the spread of foodborne disease that require preventive and corrective actions as appropriate under Sanitation Standard Operating Procedures, Good Manufacturing Practices, or pest control programs.

J Bacteriol, 1999 Mar, 181(5), 1630 - 5
Molecular survey of the Salmonella phage typing system of Anderson; Schmieger H; Typing phages for Salmonella and the prophages of their typical propagation strains were analyzed at the DNA level . Most of them belong to the P22 branch of the lambdoid phages . Acquisition of new plating properties of the typing phages by propagation in particular strains can be due to different host specific modifications of the DNA or to recombination events with residing prophages which are reflected by changes in the respective DNA restriction patterns . It is concluded that the actually available set of typing phages is a historically unique combination of strains.

J Bacteriol, 1999 Mar, 181(5), 1388 - 94
Components of the Salmonella flagellar export apparatus and classification of export substrates; Minamino T et al.; Until now, identification of components of the flagellar protein export apparatus has been indirect . We have now identified these components directly by establishing whether mutants defective in putative export components could translocate export substrates across the cytoplasmic membrane into the periplasmic space . Hook-type proteins could be exported to the periplasm of rod mutants, indicating that rod protein export does not have to precede hook-type protein export and therefore that both types of proteins belong to a single export class, the rod/hook-type class, which is distinct from the filament-type class . Hook-capping protein (FlgD) and hook protein (FlgE) required FlhA, FlhB, FliH, FliI, FliO, FliP, FliQ, and FliR for their export to the periplasm . In the case of flagellin as an export substrate, because of the phenomenon of hook-to-filament switching of export specificity, it was necessary to use temperature-sensitive mutants and establish whether flagellin could be exported to the cell exterior following a shift from the permissive to the restrictive temperature . Again, FlhA, FlhB, FliH, FliI, and FliO were required for its export . No suitable temperature-sensitive fliQ or fliR mutants were available . FliP appeared not to be required for flagellin export, but we suspect that the temperature-sensitive FliP protein continued to function at the restrictive temperature if incorporated at the permissive temperature . Thus, we conclude that these eight proteins are general components of the flagellar export pathway . FliJ was necessary for export of hook-type proteins (FlgD and FlgE); we were unable to test whether FliJ is needed for export of filament-type proteins . We suspect that FliJ may be a cytoplasmic chaperone for the hook-type proteins and possibly also for FliE and the rod proteins . FlgJ was not required for the export of the hook-type proteins; again, because of lack of a suitable temperature-sensitive mutant, we were unable to test whether it was required for export of filament-type proteins . Finally, it was established that there is an interaction between the processes of outer ring assembly and of penetration of the outer membrane by the rod and nascent hook, the latter process being of course necessary for passage of export substrates into the external medium . During the brief transition stage from completion of rod assembly and initiation of hook assembly, the L ring and perhaps the capping protein FlgD can be regarded as bona fide export components, with the L ring being in a formal sense the equivalent of the outer membrane secretin structure of type III virulence factor export systems.

Curr Opin Microbiol, 1999 Feb, 2(1), 46 - 50
Interaction of Salmonella with host cells through the centisome 63 type III secretion system; Galan JE; Salmonella enterica engages host cells in a complex two-way biochemical interaction that results in a variety of responses from both the bacteria and the host cell . Central to this interaction is the function of a type III protein secretion system that delivers effector proteins into the host cell . During the past year we have seen major advances in our knowledge of both the bacterial determinants and the host-signal transduction pathways involved in these interactions . A coherent picture of the mechanisms by which Salmonella engages the host cell is now beginning to emerge.

Mo Med, 1999 Feb, 96(2), 62 - 6
Salmonella outbreaks in the Kansas City metropolitan area: varying presentations; Wilkinson TH et al.; Four outbreaks of Salmonella in the Kansas City metropolitan area between 1996 and 1998 are used to illustrate changes in the epidemiology of foodborne diseases and recognition by public health authorities . Physicians are the critical link in the recognition of foodborne outbreaks, and that linkage is tied directly to their index of suspicion and the appropriate collection and testing of specimens from their patients, as well as notification of the local health department.

Mutat Res, 1999 Jan 13, 438(2), 145 - 53
Assessment of the utility of the micronucleus test for petroleum-derived materials; Przygoda RT et al.; The micronucleus test is a commonly used in vivo assay for chromosomal damage and is an integral part of many mutagenicity testing strategies . The present report describes an assessment of the micronucleus test for the detection of mutagenic potential of petroleum-derived materials . To this end, studies were conducted with catalytically cracked clarified oil (CCCO) . This material contains high levels of polycyclic aromatic constituents (PAC) and is a very potent inducer of mouse skin tumors . CCCO is also active in the Salmonella assay and other in vitro tests . As CCCO is the most potent of the various petroleum-derived materials in other assays, it was assumed to be the most easily detectable in the micronucleus test . CCCO was tested in standard mouse micronucleus tests utilizing oral and intraperitoneal injection for test material administration . All of these studies were negative, although DMBA, tested at roughly equivalent levels based on potency in the Salmonella assay, produced statistically significant increases in micronucleus frequency . In a second series of studies, aromatic fractions of CCCO were prepared and tested at up to acutely toxic levels . Results of these studies were also negative . Finally, another petroleum-derived material which is carcinogenic and contained PAC was tested in the micronucleus assay . It also produced negative results . Thus, it was concluded that petroleum-derived materials do not produce clastogenic effects in vivo in the mouse micronucleus test, despite the fact that some pure polycyclic aromatic hydrocarbons are quite active in this assay .

Mutat Res, 1999 Jan 13, 438(2), 109 - 23
Chemical behaviour of seven aromatic diisocyanates (toluenediisocyanates and diphenylmethanediisocyanates) under in vitro conditions in relationship to their results in the Salmonella/microsome test; Seel K et al.; There are conflicting results on the mutagenicity of toluenediisocyanate (TDI) and diphenylmethanediisocyanate (MDI) . It was found that the organic solvent chosen to dissolve the compounds dictates the outcome of the bacterial tests . The Salmonella/microsome tests showed uniformly mutagenic effects for all the compounds that were predissolved in DMSO . Due to the instability of aromatic diisocyanates in DMSO this solvent was replaced by ethyleneglycoldimethylether (EGDE) . TDI and MDI endured the dissolving and were therefore still available for the subsequent bacterial tests . Furthermore, no aromatic diamines (TDA or MDA) could be detected in EGDE prior to the start of the assays . The Salmonella/microsome tests, however, revealed unexpected differences between TDI and MDI . As previously published the four types of MDI showed negative results, whereas the data presented in this paper demonstrated mutagenic effects of all three types of TDI if EGDE is the solvent . To gain deeper insight into the chemical changes that occurred during the Salmonella/microsome test, the possible reactions were modelled in the laboratory by mixing predissolved diisocyanates with a defined surplus of water and monitoring the progress of the chemical reactions by analytical methods . Additionally, the quality of the model was checked by exposing solutions of 2,6-TDI and 4,4'-MDI to the real biological test environment . In both cases, the reaction patterns of TDI were different to those of MDI . Within 1 min, which is the maximum time needed to mix the predissolved compounds with water before they are poured onto the agar plate, the TDI content was reduced in favour of different ureas and TDA . In addition water was replaced by the complete set of test ingredients . While the TDA content remained more or less constant, the amount of residual TDI was reduced considerably . Reactions of MDI were markedly slower than those of TDI . More than 90% of the predissolved MDI remained intact when it was mixed with water . The biological test ingredients accelerated the reduction of the MDI content . Within 45 s, more than two thirds of the MDI disappeared . Evidently, the chemical reactions continue during incubation . It is assumed that the contrasting results of TDI and MDI in the Salmonella/microsome test are due to the different reaction patterns-and reaction products-of the predissolved diisocyanates created under the specific conditions of the test . These findings indicate that the chemical interactions between reactive test compounds and solvents or test media need to be considered in the interpretation of the relevance of test results .

J Ethnopharmacol, 1998 Dec, 63(3), 201 - 8
Jamu Gendong, a kind of traditional medicine in Indonesia: the microbial contamination of its raw materials and endproduct; Limyati DA et al.; An examination on the microbiological quality of seven kinds of Jamu Gendong (JG) and their raw materials has been conducted according to the requirements of microbial contamination in traditional medicine, issued by the Department of Health of Indonesia in 1986 . Samples of JG and their raw materials were taken from producers in three districts of Surabaya . The samples were subject to the following examinations: total plate count (TPC), MPN coliform, the enumeration of molds and yeasts, the presence or absence of Staphylococcus aureus, Salmonella and Vibrio . Each time the JG samples were taken from different producers together with their raw materials . The results of this investigation showed that most of the JG samples were heavily contaminated with bacteria, yeasts and molds . For bacteria, taken from the TPC results, their numbers were ranging from 7.7 x 10(2) microorganisms/ml to too many to count (TMTC) . For yeasts and molds the numbers showed variations from 0 microorganisms/ml to TMTC . Contamination with Coliform in 1 ml of JG were ranged from 0 to > 2.4 x 10(6) microorganisms . In most of the samples pathogenic Staphylococci, Salmonella sp . and Vibrio sp . were not detected, so that a conclusion can be drawn that most of the contamination in JG are saprophytic, only a few pathogenic . The results also show that it is possible to have JG which fulfill the government's requirements . Similar results were obtained with the plant material constituents of JG such as rhizomes, leaves, herbs and fruits of Piper nigrum and Piper retrofractum, with the exception of Piper betle leaves and P . retrofractum fruits, both showing low contamination of Coliform bacteria . However, the fruits of Citrus aurantifolia and Morinda citrifolia were less contaminated, just like seeds of Oryza sativa, Parkia roxburghii, bulbs of Allium sativum and the pulp of Tamarindus indica . With these plant constituents of JG, it might be of interest to screen their antibacterial and antifungal activities.

Epidemiol Infect, 1998 Dec, 121(3), 561 - 7
Risk factors for the occurrence of sporadic Salmonella enterica serotype enteritidis infections in children in France: a national case-control study; Delarocque-Astagneau E et al.; To determine risk factors associated with the occurrence of sporadic cases of Salmonella enteritidis infections among children in France, we conducted a matched case-control study . Cases were identified between 1 March and 30 September 1995 . One hundred and five pairs of cases and controls matched for age and place of residence were interviewed . In the 1-5 years age group, illness was associated with the consumption of raw eggs or undercooked egg-containing foods (OR 2.4, 95% CI 1.2-4.8) . Storing eggs more than 2 weeks after purchase was associated with Salmonella enteritidis infection (OR 3.8, 95% CI 1.4-10.2), particularly during the summer period (OR 6.0, 95% CI 1.3-26.8) . Cases were more likely to report a case of diarrhoea in the household 10-3 days before the onset of symptoms, particularly in the age group < or = 1 year (P = 0.01) . This study confirms the link between eggs and the occurrence of sporadic cases of Salmonella enteritidis among children, highlights the potential role of prolonged egg storage and underlines the role of person-to-person transmission in infants.

Epidemiol Infect, 1998 Dec, 121(3), 555 - 9
Emergence of multidrug-resistant Salmonella enterica serotype Typhimurium phage-type DT104 among salmonellae causing enteritis in Israel; Metzer E et al.; The relative frequency of salmonella strains isolated from hospitalized and non-hospitalized patients in Southern Israel changed during the period, 1994-6 . Salmonella enterica serotype Typhimurium definitive phage-type 104 (DT104) appeared in Israel in 1994 and became the most prevalent strain in 1996 . An outbreak of enteritis due to Salmonella enterica serotype Agona occurred in Israel, in October 1994 and lasted for 4 months . The relative frequency of Salmonella enterica serotype Enteritidis remained almost constant during these years, with seasonal fluctuations only . The importance of the increase in the prevalence of Typhimurium DT104 has been the epidemic spread of a multiresistant strain of R-type ACT (A, ampicillin; C, chloramphenicol; T, tetracycline) belonging to this phage-type . Since 1995 the frequency of Typhimurium DT104 isolates that possess, in addition to the above R-type, a chromosomally encoded resistance to the quinolone drug, nalidixic acid, increased tenfold . In 1996, 27% of the Typhimurium DT104 isolates were of R-type ACTN . S . Enteritidis exhibited over 95% susceptibility to at least eight of the most commonly used antibiotic drugs, and none of the isolates was resistant to quinolone or fluoroquinoline.

J Food Prot, 1999 Feb, 62(2), 198 - 201
Evaluation of immunomagnetic separation and plating media for recovery of Salmonella from meat; Ripabelli G et al.; Immunomagnetic separation (IMS) was compared with selective enrichment in selenite cystine (SC) broth for isolation of Salmonella from 86 artificially contaminated ground beef samples . Both Rambach agar (RA) and Hektoen enteric (HE) agar were used as selective plating media . The highest count of Salmonella colonies per plate was obtained after enrichment in SC broth and plating on RA (mean value: 111.1+/-58.1 CFU per plate); the lowest count was obtained after IMS and plating on HE agar (mean value: 65.4+/-36.6 CFU per plate) . Salmonella in preenrichment was concentrated 1.7-fold by IMS and represented 31% of the microbial population captured by the beads, but nonspecific binding was high . As a result of the large numbers of competing bacteria, isolations on both RA and HE agar following IMS were quite difficult (mean value for Salmonella colonies: 79.9+/-42.7 CFU per plate; mean value for non-Salmonella colonies: 144.1+/-75.7 CFU per plate; ratio of Salmonella to non-Salmonella colonies: 0.8) . This study indicates that SC broth is superior to IMS in the isolation of Salmonella from raw ground meat.

J Food Prot, 1999 Feb, 62(2), 140 - 5
Sources and extent of microbiological contamination of beef carcasses in seven United States slaughtering plants; Sofos JN et al.; This study determined microbiological loads of beef carcasses at different stages during the slaughtering to chilling process in seven (four steer/heifer and three cow/bull) plants . Potential sources of contamination (feces, air, lymph nodes) were also tested . Each facility was visited twice, once in November through January (wet season) and again in May through June (dry season) . Carcasses were sampled by aseptic excision of surface tissue (100 cm2) from the brisket, flank, and rump (30 samples each) after hide removal (pre-evisceration), after final carcass washing, and after 24-h carcass chilling . The samples were analyzed individually by standard procedures for aerobic plate counts (APC), total coliform counts (TCC), Escherichia coli biotype I counts (ECC), and presence of Salmonella . Incidence of Salmonella was higher on dry feces of older compared to younger animals, fresh feces of younger compared to older animals, and on cow/bull carcasses compared to steer/heifer carcasses . Most factors and their interactions had significant (P < or = 0.05) effects on the bacterial counts obtained . Depending on plant and season, APC, TCC, and ECC were < or =10(4), < or =10(2), and < or =10(1) CFU/cm2 in 46.7 to 93.3, 50.0 to 100.0, and 74.7 to 100.0% of the samples, respectively . TCC exceeded 10(3) CFU/cm2 in 2.5% (wet season) and 1.5% (dry season) of the samples . ECC exceeded 10(2) CFU/cm2 in 8.7%, 0.3%, and 1.5% of the pre-evisceration, final carcass-washing, and 24-h carcass-chilling samples, respectively, during the wet season; the corresponding numbers during the dry season were 3.5%, 2.2%, and 3.0%, respectively . These data should serve as a baseline for future comparisons in measuring the microbiological status of beef carcasses, as the new inspection requirements are implemented.

J Food Prot, 1999 Feb, 62(2), 118 - 22
Salmonella Thompson associated with improper handling of roast beef at a restaurant in Sioux Falls, South Dakota; Shapiro R et al.; In October 1996, we investigated an outbreak of Salmonella serotype Thompson infections associated with Restaurant A in Sioux Falls, South Dakota, and conducted two cohort studies among persons who ate at luncheons catered by Restaurant A . Fifty-two Salmonella Thompson infections were identified between 29 September and 14 October 1996 . Infections occurred among employees and patrons at Restaurant A and among attendees at three luncheons catered by the restaurant on 7 October . Roast beef cooked at Restaurant A was the only food item significantly associated with illness . Cooking times and storage temperatures for roast beef were inadequate to prevent multiplication of Salmonella, and the chefs were unaware of proper cooking and storage temperatures . We conclude that improper handling of roast beef probably caused this outbreak of Salmonella Thompson infections . Better knowledge of food safety practices by the cooking staff at Restaurant A, through required food safety education, might have prevented the outbreak.

J Food Prot, 1999 Feb, 62(2), 112 - 7
Use of capillary tubes and plate heat exchanger to validate U.S . Department of Agriculture pasteurization protocols for elimination of Salmonella enteritidis from liquid egg products; Michalski CB et al.; D values for a five-strain cocktail of Salmonella Enteritidis in five different liquid egg products (whole egg, egg yolk, egg white, egg yolk + 5% sucrose + 5% NaCl, and egg yolk + 10% NaCl) were determined using 100-microl capillary tubes . The egg products were inoculated with approximately 1 X 10(10) organisms/ml and heated in capillary tubes to temperatures ranging from 51 to 68 degrees C for various time intervals . Using a pilot scale plate heat exchanger, the U.S . Department of Agriculture (USDA) protocols for pasteurization were also evaluated using egg products inoculated with approximately 1 x 10(7) Salmonella Enteritidis/ml . Results of experiments with capillary tubes suggested that almost all processes would result in less than the 9D process recommended by the USDA . However, when the egg products were pasteurized using the plate heat exchanger, a greater than 9D process was achieved for Salmonella Enteritidis in all products except egg yolk containing 5% sucrose + 5% NaCl, which received approximately a 4D process.

Rev Saude Publica, 1998 Oct, 32(5), 477 - 83
{Food borne disease outbreaks caused by Salmonella enteritidis}; Peresi JT et al.; OBJECTIVE: It is to describe outbreaks of salmonellosis reported from July 1993 through June 1997 in the Northwest region of S . Paulo State, Brazil, one of the areas where several foodborne outbreaks of salmonellosis have been recently detected . METHOD: Data of 19 epidemiological investigations were analysed; 87 stool specimens and 38 food samples (including 12 of shell eggs) were processed for microbiological analysis . Salmonella strains were identified by serotyping, phagetyping and antimicrobial susceptibility testing . RESULTS: There were 906 ill persons including 295 hospitalized patients . Phage type 4 (PT 4) Salmonella Enteritidis strains were isolated from 80.5% of stool samples, from all food samples and from 41.7% of eggs . Of the outbreaks, 95.7% were associated with the consumption of food containing raw or undercooked eggs . All strains were susceptible to the 13 antimicrobials, except the strains from the nosocomial outbreak . CONCLUSIONS: The results obtained show the need for the implementation of control measures regarding egg and storage, as well as for guidance to the public as to the risks involved in the consumption of inadequately prepared eggs.

Lett Appl Microbiol, 1999 Jan, 28(1), 36 - 40
The fate of Salmonella enteritidis PT4 in home-made mayonnaise prepared with citric acid; Xiong R et al.; The fate of Salmonella enteritidis PT4 in home-made mayonnaise prepared with citric acid solution (citric acid concentration of > or = 4.98% (w/v)) was investigated . It was found that pH of mayonnaise is closely related to the ratio of egg yolk to citric acid, and the inactivation rate of the micro-organisms increases as the ratio decreases and/or incubation temperature increases . To achieve Salm . enteritidis PT4-free home-made mayonnaise prepared with pure lemon juice (citric acid concentration > or = 5% (w/v)), it is recommended that the pH should be 3.30 or below, or, in practice, at least 20 ml pure lemon juice per fresh egg yolk should be used . For the use of 20-35 ml pure lemon juice per egg yolk, the product should be held at 22 degrees C or over for at least 72 h and for the use of over 35 ml pure lemon juice per egg yolk, for at least 48 h before consumption or refrigeration.

Mutat Res, 1999 Feb 2, 439(1), 37 - 47
Comparison of SYBR Green I nucleic acid gel stain mutagenicity and ethidium bromide mutagenicity in the Salmonella/mammalian microsome reverse mutation assay (Ames test); Singer VL et al.; SYBR Green I nucleic acid gel stain is an unsymmetrical cyanine dye developed for sensitive detection of nucleic acids in electrophoretic gels . Its mechanism of nucleic acid binding is not known, whereas the most commonly used nucleic acid gel stain, ethidium bromide, is a well-characterized intercalator . We compared the mutagenicity of SYBR Green I stain with that of ethidium bromide in Salmonella/mammalian microsome reverse mutation assays (Ames tests) . As expected {J . McCann, E . Choi, E . Yamasaki, B.N . Ames, Proc . Natl . Acad . Sci . USA, 72 (1975) 5135-5139}, ethidium bromide showed high revertant frequencies in several frameshift indicator strains (averaging 68-fold higher than vehicle controls in TA98, 80-fold higher in TA1538, 15-fold higher in TA1537, and 4.4-fold higher in TA97a), only in the presence of rat liver extracts (S9) . Small increases in revertant frequencies were observed for ethidium bromide in the base-substitution indicator strain TA102 both in the presence and absence of S9 (averaging 2.0- and 1.8-fold higher than vehicle controls, respectively) and in base-substitution indicator strain TA100 in the presence of S9 (averaging 1.6-fold higher than vehicle controls) . A small mutagenic effect was detected for SYBR Green I stain in frameshift indicator strain TA98 (averaging 2 . 2-fold higher than vehicle controls) only in the absence of S9 and in base-substitution indicator strain TA102, both in the presence and absence of S9 (averaging 2.2- and 2.7-fold higher than vehicle controls, respectively) . Thus, SYBR Green I stain is a weak mutagen and appears to be much less mutagenic than ethidium bromide . These results suggest that SYBR Green I stain may not intercalate, and if it does, that its presence does not give rise to point mutations at a high frequency .

Br J Haematol, 1999 Jan, 104(1), 93 - 6
Day-care management of sickle cell painful crisis in Jamaica: a model applicable elsewhere?
Ware MA, Hambleton I, Ochaya I, Serjeant GR.
In the U.K . and the U.S.A., painful crises account for 80-90% of sickle-related hospital admissions, with average durations of 5-11 d . In Jamaica, many severe painful crises are managed in a day-care centre . Patients (n=1160) with homozygous sickle cell (SS) disease aged 18 years and over were registered with the clinic during a 1-year study period . Of these, 216 patients with 476 painful crises attended the day-care facility for a total of 686 d . Most patients (119 or 55.1%) had single crises and for most crises (338 or 71%), patients attended for only 1 d, when they were given bed rest, assurance, rehydration and analgesia . Patients with complicated painful crises were usually referred for admission after initial pain relief and the rest were monitored during the day . In the evening they were given the option of hospital admission or allowed home with oral analgesia . Hospital admission for complicated painful crises or inadequate pain relief occurred in 42 (8.8%) crises and home management in 434 (91.2%) crises . Of 186 patients initially selecting home management, 20% returned for further day-care and five (2.7%) died during subsequent admission for that painful crisis, one without other known complications, two with acute chest syndrome (one associated with Salmonella septicaemia), another with Salmonella septicaemia, and one with dengue haemorrhagic fever . With suitable oral analgesia, adequate education and support, the majority of severe painful crises in SS disease in Jamaica have been managed on an outpatient basis . This model of patient care may merit assessment in other communities where painful crises are a common clinical problem.

Wien Klin Wochenschr, 1998 Dec 11, 110(23), 824 - 33
Investigations on genotoxic effects of groundwater from the Mitterndorfer Senke and from the vicinity of Wiener Neustadt; Knasmuller S et al.; INTRODUCTION: This report describes the first study on genotoxic effects of Austrian ground- and drinking waters . Samples from the Mitterndorfer Senke (MS) and the vicinity of Wiener Neustadt were tested over a three years period . The MS is the largest aquifer in Austria . Due to deposition of industrial and community wastes, chemicals have polluted the groundwater in this area . Aim of the present study was to elucidate if consumption of these waters might pose a carcinogenic risk to humans . METHODS: 43 Water samples were tested in a test battery which consisted of bacterial gene mutation assays (Salmonella strains TA100 and TA98), micronucleus (MN) assays with cultures of primary rat hepatocytes and plant bioassays (MN tests with Tradescantia and Vicia faba) . For the bacterial assays, the water samples were extracted with XAD resins . RESULTS: In total, 27.9% of the samples caused positive effects; 8 samples were active in Salmonella microsome assays, Strain TA100 was particularly sensitive upon addition of metabolic activation mix (6 positive samples) . Four samples were positive exclusively in MN assays with cultures of primary rat hepatocytes; one sample gave positive results in all three bioassays . Finished waters from waterworks were consistently devoid of mutagenic activity under all experimental conditions . DISCUSSION: Overall, only a small fraction of the groundwaters caused mutagenic effects and in all cases the activities were moderate . Comparison of the results of the present study with data obtained in other investigations under similar experimental conditions shows that the genotoxicity of groundwaters of the MS area are lower than the effects caused by ground- and drinking waters from other countries . The fact that no genotoxic activity was detected in any of the finished drinking waters can be taken as an indication that consumption of these waters does not pose a health hazard arising from contamination with genotoxic carcinogens to humans.

Infect Immun, 1999 Mar, 67(3), 1338 - 46
Potent immunoregulatory effects of Salmonella typhi flagella on antigenic stimulation of human peripheral blood mononuclear cells; Wyant TL et al.; A key function of monocytes/macrophages (Mphi) is to present antigens to T cells . However, upon interaction with bacteria, Mphi lose their ability to effectively present soluble antigens . This functional loss was associated with alterations in the expression of adhesion molecules and CD14 and a reduction in the uptake of soluble antigen . Recently, we have demonstrated that Salmonella typhi flagella (STF) markedly decrease CD14 expression and are potent inducers of proinflammatory cytokine production by human peripheral blood mononuclear cells (hPBMC) . In order to determine whether S . typhi and soluble STF also alter the ability of Mphi to activate T cells to proliferate to antigens and mitogens, hPBMC were cultured in the presence of tetanus toxoid (TT) or phytohemagglutinin (PHA) and either killed whole-cell S . typhi or purified STF protein . Both whole-cell S . typhi and STF suppressed proliferation to PHA and TT . This decreased proliferation was not a result of increased Mphi production of nitric oxide, prostaglandin E2, or oxygen radicals or the release of interleukin-1beta, tumor necrosis factor alpha, interleukin-6, or interleukin-10 following exposure to STF . However, the ability to take up soluble antigen, as determined by fluorescein isothiocyanate-labeled dextran uptake, was reduced in cells cultured with STF . Moreover, there was a dramatic reduction in the expression of CD54 on Mphi after exposure to STF . These results indicate that whole-cell S . typhi and STF have the ability to alter in vitro proliferation to soluble antigens and mitogens by affecting Mphi function.

Infect Immun, 1999 Mar, 67(3), 1180 - 6
Activation of murine macrophages by lipoprotein and lipooligosaccharide of Treponema denticola; Rosen G et al.; We have recently demonstrated that the periodontopathogenic oral spirochete Treponema denticola possesses membrane-associated lipoproteins in addition to lipooligosaccharide (LOS) . The aim of the present study was to test the potential of these oral spirochetal components to induce the production of inflammatory mediators by human macrophages, which in turn may stimulate tissue breakdown as observed in periodontal diseases . An enriched lipoprotein fraction (dLPP) from T . denticola ATCC 35404 obtained upon extraction of the treponemes with Triton X-114 was found to stimulate the production of nitric oxide (NO), tumor necrosis factor alpha (TNF-alpha), and interleukin-1 (IL-1) by mouse macrophages in a dose-dependent manner . Induction of NO by dLPP was at 25% of the levels obtained by Salmonella typhosa lipopolysaccharide (LPS) at similar concentrations, while IL-1 was produced at similar levels by both inducers . dLPP-mediated macrophage activation was unaffected by amounts of polymyxin B that neutralized the induction produced by S . typhosa LPS . dLPP also induced NO and TNF-alpha secretion from macrophages isolated from endotoxin-unresponsive C3H/HeJ mice to an extent similar to the stimulation produced in endotoxin-responsive mice . Purified T . denticola LOS also produced a concentration-dependent activation of NO and TNF-alpha in LPS-responsive and -nonresponsive mouse macrophages . However, macrophage activation by LOS was inhibited by polymyxin B . These results suggest that T . denticola lipoproteins and LOS may play a role in the inflammatory processes that characterize periodontal diseases.

Poult Sci, 1999 Jan, 78(1), 57 - 61
Application of negative air ionization for reducing experimental airborne transmission of Salmonella enteritidis to chicks; Gast RK et al.; Electrostatic space chargers were used to impart a negative charge to airborne dust particles and thereby cause them to be attracted to grounded surfaces . To determine whether negative air ionization could affect the airborne transmission of Salmonella enteritidis, chicks were housed in four controlled-environment isolation cabinets in which airflow was directed across an unoccupied central area from one ("upstream") group of birds to another ("downstream") group . Negative air ionizers were installed in two of these cabinets . In three replicate trials, groups of chicks were placed in the upstream ends of the transmission cabinets and orally inoculated with S . enteritidis at 1 wk of age . On the following day, 1-d-old chicks were placed in the downstream ends of the cabinets . When chicks were sampled at 3 and 8 d postinoculation, S . enteritidis was found on the surface of 89.6% of the downstream chicks from cabinets without negative air ionizers, but on only 39.6% of the downstream chicks in the presence of the ionizers . Similarly, S . enteritidis was recovered from the ceca of 53.1% of sampled downstream chicks in cabinets without ionizers, but from only 1.0% of the ceca of chicks in cabinets in which ionizers were installed . The presence of the ionizers was also associated with reduced levels of circulating airborne dust particles . Reducing airborne dust levels may thus offer an opportunity to limit the spread of S . enteritidis infections throughout poultry flocks.

Poult Sci, 1999 Jan, 78(1), 45 - 9
Presence of Salmonella in the crop and ceca of broiler chickens before and after preslaughter feed withdrawal; Corrier DE et al.; Recent studies have suggested that crop contents may serve as an important source of Salmonella carcass contamination within processing plants . During the present study, we evaluated the effect of preslaughter feed withdrawal on the presence of Salmonella in the crops of broilers from nine commercial broiler flocks reared in individual growout houses . Crops were collected aseptically from 40 randomly selected broilers in each flock before feed removal and at the end of the feed withdrawal period, immediately before capture and transport to the processing plant . Similarly, the ceca were collected before and after feed withdrawal in six of the nine broiler flocks . The presence of Salmonella in the crops and ceca was determined by enrichment culture in tetrathionate broth followed by culture on brilliant green agar . The incidence of Salmonella in crop contents increased significantly (P < 0.05) in five of the nine flocks during feed withdrawal . The total number of Salmonella contaminated crops from all nine flocks increased significantly (P < 0.005) from 7/360 (1.9%) before feed removal to 36/359 (10.0%) at the end of feed withdrawal . The increased incidence of Salmonella in the crop contents was associated with an increased tendency of the broilers to consume contaminated rearing house litter during feed withdrawal . The incidence of Salmonella in the ceca increased nonsignificantly from 14/240 (5.8%) before feed removal to 19/240 (7.9%) at the end of feed withdrawal . The results indicate that the incidence of Salmonella crop contamination may increase as much as fivefold during preslaughter feed withdrawal and represent a critical preharvest control point in reducing Salmonella entry into the processing plant.

Poult Sci, 1999 Jan, 78(1), 32 - 7
Evaluation of potential disinfectants for preslaughter broiler crop decontamination; Barnhart ET et al.; The broiler crop has recently been implicated as a major source of Salmonella contamination at commercial processing . Furthermore, feed withdrawal has been positively correlated with increased Salmonella incidence in the crop, probably due to coprophagy . In the present study, a rapid screening assay was developed to evaluate several potential disinfectants in the presence of large quantities of organic matter, simulating the crop environment . An apparent synergistic combination of d-Limonene (DL) and citric acid (CA) was observed when evaluating the potential to eliminate Salmonella in the presence of organic material . A method of encapsulation of DL and CA was developed for voluntary consumption by broilers during feed withdrawal . During an 8-h feed withdrawal individual 8-wk-old broilers voluntarily consumed an average of 21.5 capsules (total of 3.44 g material) . When eight capsules were force-administered to Salmonella-challenged 8-wk-old broilers during an abbreviated 4 h feed withdrawal, Salmonella was not recovered using selective enrichment . To evaluate the effect of voluntary capsule consumption, 8-wk-old broilers were challenged with 1 x 108 cfu of Salmonella 5 d prior to an 8 h feed withdrawal . When these broilers were allowed unlimited continuous access to capsules containing DL/CA during an 8 h feed withdrawal, 24.8 capsules per broiler were ingested without affecting Salmonella recovery from crops . When access to capsules containing DL/CA was limited to the final 45 min of an 8 h feed withdrawal in a similar experiment, an average of 22.2 capsules were consumed by each broiler, resulting in a significant decrease in the number of Salmonella-positive crops . Although a number of practical questions and considerations remain, these data suggest that appropriate disinfectants could be administered during preslaughter feed withdrawal for the purpose of reducing foodborne pathogens in crops.

Poult Sci, 1999 Jan, 78(1), 24 - 31
Use of arbitrarily primed polymerase chain reaction to study Salmonella ecology in a turkey production environment; Guo L et al.; Turkeys, liners, waterers, litter, air, and feed weighbacks were sampled for Salmonella . Salmonella species S . simsbury, S . kentucky, S . montevideo, S . senftenberg, and S . ealing were identified at a rate of 54.9, 38.0, 2.8, 2.8, and 1.4% respectively . All isolates were subjected to Salmonella-specific polymerase chain reaction (PCR) and were confirmed as Salmonella-positive by the predicted product, a 457-bp DNA fragment . Biofingerprint patterns of each isolate were generated using arbitrary primer sets, LG6+LG8 and LG6+LG9 . These primer sets differentiated between Salmonella serotypes except for S . simsbury and S . senftenberg . No differences in fingerprint patterns were observed among farm isolates that were the same serotype . This similarity suggested that these isolates were from a common origin or that primer sets could not distinguish isolates at the subserotype level . Frequency of Salmonella isolation decreased from Week 10 to 18 of the growout period . Resistance of older birds to Salmonella colonization, due to a more mature gut microflora, may account for this observation . Results demonstrate that arbitrarily primed-PCR (AP-PCR) can effectively differentiate among serotypes except for S . simsbury and S . senftenberg; results regarding potential to differentiate at the subserotype level were inconclusive.

Mutat Res, 1999 Feb 19, 439(2), 159 - 69
New O-acetyltransferase-deficient Ames Salmonella strains generated by specific gene disruption; Espinosa-Aguirre JJ et al.; CoASAc-dependent N-hydroxyarylamine O-acetyltransferase (OAT) is an enzyme involved in the intracellular metabolic activation of N-hydroxyarylamines derived from mutagenic nitroarenes and aromatic amines . The oat gene encoding the enzyme of S . typhimurium TA98 and TA100 was specifically disrupted and the sensitivities of the resulting strains, i.e., YG7130 and YG7126, to mutagens were compared with those of the conventional oat-deficient strains, i.e., TA98/1,8DNP6 and TA100/1,8DNP, respectively . The new oat-deficient strains and the conventional strains exhibited similar sensitivity against most of the chemicals tested: both strains YG7130 and strain TA98/1,8-DNP6 were resistant to mutagenicity by 1,8-dinitropyrene (1, 8-DNP), 1-nitropyrene, 2-amino-6-methyldipyrido{1,2-alpha:3', 2'-d}imidazole (Glu-P-1) and 2-amino-3-methyl-3H-imidazo{4, 5-f}quinoline (IQ); neither strain YG7130 nor strain TA98/1,8-DNP6 was resistant to the mutagenicity of 3-amino-1-methyl-5H-pyrido{4, 3-b}indole (Trp-P-2); strain YG7126 and strain TA100/1,8-DNP were refractory to the mutagenicity of 1,8-DNP . However, the order of the sensitivity against 2-nitrofluorene (2-NF) was TA98>YG7130>TA98/1, 8-DNP6 and TA100>YG7126>TA100/1,8-DNP . Since the strains YG7130 and YG7126 have chloramphenicol resistance (Cmr) gene in place of the chromosomal oat gene for gene disruption, the possible involvement of chloramphenicol acetyltransferase (CAT) encoded by the Cmr gene in the activation of 2-NF was examined . Strikingly, introduction of plasmid pACYC184 carrying the Cmr gene alone substantially enhanced the sensitivity of the conventional oat-deficient strains to 2-NF . These results suggest that the new strains as well as the conventional strains are useful to assess the roles of OAT in the metabolic activation of nitroaromatics and aromatic amines in S . typhimurium, and also that CAT has the ability to activate N-hydroxy aromatic amines to mutagens .

Toxicol Lett, 1998 Dec 28, 102-103, 627 - 9
Toxicity prediction of chemicals based on structure-activity relationships; Nakadate M; The prediction system of chemical toxicity has been developed by means of structure-activity relationships (SARs) based on the computerized fact database (BL-DB) . Number and ratio of elements, side chains, bonding, position and microenvironment of side chains were used as the structural factors of chemicals for toxicity prediction . Such information was obtained from BL-DB by Wiswesser line notation . In the present study, the Salmonella-microsome assay of the mutagenicity was chosen as indicative of the target toxicity of chemicals . A set of chemicals specified with mutagenicity data was retrieved, and the necessary information was extracted and transferred to the working file . Rules of the relation between characteristics of chemical structure and the assay results are extracted as parameters for rules by experts on rearranged data set . There are analysed statistically by discriminant analysis and prediction and the rules were evaluated by the elimination method . For example, eight kinds of rules to predict Salmonella/microsomal assay were constructed, and currently results of the assay on organic compounds can be predicted above 90% accuracy.

Toxicol Lett, 1998 Dec 28, 102-103, 473 - 8
Validation of transgenic mice harboring the human prototype c-Ha-ras gene as a bioassay model for rapid carcinogenicity testing; Yamamoto S et al.; Studies were conducted to validate the transgenic (Tg) mice harboring human prototype c-Ha-ras gene, namely the rasH2 mice (CB6F1), as a model for rapid carcinogenicity testing . Short-term (26 weeks) carcinogenicity testing of 18 mutagenic (Salmonella) trans-species carcinogens, two mutagenic single-species (mouse-only) carcinogens, six non-mutagenic trans-species carcinogens, one non-mutagenic single-species (mouse-only) carcinogen, four mutagenic non-carcinogens and four non-mutagenic non-carcinogens were completed . The studies revealed that the Tg mice are able to detect various types of mutagenic carcinogens and may also detect various non-mutagenic carcinogens within 26 weeks . Dose-dependent tumor responses were observed with various carcinogens except for a few equivocal cases . The validation studies also revealed that the Tg mice are generally much more susceptible to both mutagenic and non-mutagenic carcinogens than control non-Tg mice . Most of the malignant tumors were observed in the carcinogen-treated Tg mice and only very few or none in the corresponding non-Tg mice . Most of the carcinogens tested induced some of the target organ tumors observed in B6C3F1 mice in a 2-year bioassay as well as certain types of tumors specific to the Tg mice, i.e . lung alveolar epithelial tumors, spleen hemangiosarcomas, forestomach squamous cell tumors . No significant tumor induction has been observed in the Tg mice either with mutagenic or non-mutagenic non-carcinogens . Although further validation studies are still required, the rasH2 mouse seems to be a promising candidate as an animal model for the development of a rapid carcinogenicity testing system.

Am J Public Health, 1999 Jan, 89(1), 31 - 5
Consequences in Georgia of a nationwide outbreak of Salmonella infections: what you don't know might hurt you; Mahon BE et al.; OBJECTIVES: This study assessed the impact in Georgia of a nationwide salmonellosis outbreak caused by ice cream products and the effectiveness of the subsequent warning against eating the implicated products . METHODS: A telephone survey of 250 randomly selected Georgia customers of the ice cream producer was conducted 13 to 17 days after the warning . RESULTS: Respondents from 179 households representing 628 persons were interviewed . The median date of first hearing the warning was 5 days after it was issued, and 16 respondents (9%) had not heard it . Among those who had heard the warning, 42 (26%) did not initially believe the products were unsafe . In 22 (31%) of the 72 households that had the implicated ice cream when the respondent heard the warning, someone subsequently ate the ice cream . Diarrhea was reported in 26% (121/463) of persons who had eaten the products but in only 5% (8/152) who had not (odds ratio {controlling for household clustering} = 3.8; 95% confidence interval = 2.0, 7.5) . We estimate this outbreak caused 11,000 cases of diarrhea in Georgia, 1760 (16%) with exposure after the warning . CONCLUSIONS: A large outbreak occurred in Georgia, much of which might have been prevented by a more timely and convincing warning.

Vaccine, 1999 Jan 21, 17(3), 229 - 36
Homing potentials of circulating antibody-secreting cells after administration of oral or parenteral protein or polysaccharide vaccine in humans; Kantele A et al.; The site of antigen encounter influences the Ig-distribution and homing potentials of circulating antibody-secreting cells (ASC) induced . After oral antigen administration, the majority ASC secrete the mucosal Ig-isotype, IgA, and all of them express the gut homing receptor (HR), alpha 4 beta 7, thus implying mucosal homing of these cells . Parenteral protein vaccine induces an IgG-dominated response with a low proportion of alpha 4 beta 7 expressing cells . However, a polysaccharide vaccine, even if administered parenterally, elicits an IgA-dominated response, hence suggesting homing to the mucosa . In order to study the influence of the nature of the antigen on the targeting of the ASC response, the present work compares the homing potentials of circulating ASC in humans after administration of an oral Salmonella Typhi Ty21a vaccine (antigen studied: O-9,12 polysaccharide), an oral recombinant cholera vaccine (antigen studied: cholera toxin B-subunit, CTB protein), a parenteral pneumococcal vaccine (antigen studied: Pnc capsular polysaccharide 19F) or a parenteral tetanus toxoid vaccine (antigen studied: TT protein) . alpha 4 beta 7 was expressed on a higher proportion of ASC induced by oral O-9,12 (99%) and CTB (99%) than by parenteral Pnc (70%) or TT (63%) . L-selectin, the peripheral lymph node HR, was expressed on a smaller proportion of ASC induced by O-9,12 (37%) or CTB (43%) than of those induced by Pnc (78%) or TT (81%) . The results imply that even if the nature of the antigen has a profound effect on the Ig-distribution of the ASC response, it does not seem to influence the targeting of the response.

J Clin Microbiol, 1999 Mar, 37(3), 762 - 5
Comparison of CHROMagar Salmonella medium and hektoen enteric agar for isolation of salmonellae from stool samples; Gaillot O et al.; CHROMagar Salmonella (CAS), a new chromogenic medium, was retrospectively compared to Hektoen enteric agar (HEA) with 501 Salmonella stock isolates and was then prospectively compared to HEA for the detection and presumptive identification of Salmonella spp . with 508 stool samples before and after enrichment . All stock cultures (100%), including cultures of H2S-negative isolates, yielded typical mauve colonies on CAS, while 497 (99%) isolates produced typical lactose-negative, black-centered colonies on HEA . Following overnight incubation at 37 degreesC, a total of 20 Salmonella strains were isolated from the 508 clinical samples . Sensitivities for primary plating and after enrichment were 95% (19 isolates) and 100% (20 isolates), respectively, for CAS and 80% (16 isolates) and 100% (20 isolates), respectively, for HEA . The specificity of CAS (88.9%) was significantly higher than that of HEA (78.5%; P < 0.0001) . On the basis of its good sensitivity and specificity, CAS medium can be recommended for use for primary plating when human stool samples are screened for Salmonella spp.

Minerva Chir, 1998 Nov, 53(11), 877 - 82
{99mTc pertechnetate scintigraphy and premedication for the search for ectopic gastric mucosa in Meckel's diverticulum}; Rampin L et al.; BACKGROUND: Meckel's diverticulum (MD) is the most common anomaly of the large intestinal tract (1-3%) and is more frequent in children (62% < 2 years) and in males (66%) . It often involves ectopic gastric mucosa which manifests through gastrointestinal bleeding in 50% of cases . 99m-Technetium scintigraphy (99mTcO4) is one of the procedures available for the non-invasive diagnosis of ectopic gastric mucosa . METHODS: Twenty-eight patients (11 females, 17 males), including 16 children and 12 adults, aged 8 months-80 years old, were included in the study . The patients were admitted to hospital for hematochezia and melena (22) associated with abdominal pain (5): 3 patients repeatedly presented occult blood in their stools . Two patients only suffered from abdominal cramps and one only anemia . Patients were studied using plain abdominal radiographs and ultrasound; 10 underwent gastroscopy and colonoscopy; radiological contrast studies were performed in 5 patients . All tests were inconclusive . All the patients were premedicated with oral cimetidine (20 mg/kg in pediatric patients and 300 mg q.i.d . for adults, 48 hours before the test) or with ranitidine i.v . (1 mg/kg, max 50 mg, in 20 minutes, one hour before the test); barium meals and colonoscopy were deferred for 2-3 days after examination . An intravenous injection of 37-180 Mbq of 99mTcO4 was given followed by a dynamic study of the abdomen in anterior projection . Images were acquired for one hour or until the visualisation of abnormal foci of intake: in this case, lateral and oblique images were acquired for a better localisation of the suspicious area . Some patients were administered furosemide i.v . (0.75 mg/kg) . All underwent a follow-up period of 12 months . RESULTS: Pertechnetate scintigraphy was positive in 10 cases and the presence of ectopic gastric mucosa was confirmed by surgery . The study was negative in 18 cases: 3 of them were discharged with a diagnosis of Salmonella infection, polyp of the small bowel or ulcer of the large bowel respectively; the other 15 patients did not show symptoms of onset during follow-up . CONCLUSIONS: These results confirm the high diagnostic accuracy of pertechnetate scintigraphy to detect ectopic gastric mucosa if associated with H2-receptor-blocking agent premedication.

J Trop Pediatr, 1998 Dec, 44(6), 332 - 4
Comparison of survival of diarrhoeagenic agents in two local weaning foods (ogi and koko); Bakare S et al.; The pH values of both cooked and uncooked ogi and koko samples were determined and the survival rate of four diarrhoeagenic agents, enteroinvasive Escherichia coli, Salmonella typhi, Shigella flexneri, and Vibrio cholerae were studied after they were seeded into cooked ogi and koko . Analysis of the pH of the cooked inoculated samples showed that there was a slight increase in pH (decrease in acidity) during storage for 48 h and 37 degrees C (from 3.5 to 3.7 for ogi and from 3.7 to 4.1 for koko) . The study also showed that ogi had a slightly lower pH value than koko both before and after cooking . In both cases, the cooked samples had a slightly lower pH value than the uncooked samples . The pH value of ogi ranged from 3.0 to 3.6 and that of koko from 3.5 to 3.9 . The survival experiment showed that the inoculated enteric pathogens were inhibited in cooked ogi and koko during storage for 24-48 h . The antibacterial effect of cooked koko was more pronounced, on the four enteric pathogens studied, than that of cooked ogi . Except for Shigella flexneri and E . coli in ogi, non of the other bacteria studied was recovered after 24 h.

J Immunol, 1999 Feb 1, 162(3), 1603 - 10
Mucosal DNA vaccine immunization against measles with a highly attenuated Shigella flexneri vector; Fennelly GJ et al.; An intranasal vaccine vector would elicit protective immunity at the respiratory mucosa, the portal of entry and the primary site for replication for measles virus (MV) and other respiratory viruses . In a murine model of pulmonary Shigella, we demonstrate here that a candidate-attenuated Shigella vaccine vector is safely tolerated in IFN-gamma deficient mice at an inoculum that is 1 million-fold higher than the inoculum of the wild-type parent strain that would be lethal for greater than 90% of these mice . Also, following intranasal inoculation, the Deltaasd Shigella harboring a DNA MV vaccine plasmid induces a vigorous MV-specific Th1-type (both CD8+ CTL and IFN-gamma) and, to a lesser degree, Th2-type responses among splenocytes in addition to low levels of IgG and IgA in the serum . Priming for MV-specific CTL responses was possible in mice that had prior infection with a wild-type Shigella of the same serotype . Remarkably, mice immunized by the intranasal route with attenuated Shigella harboring the DNA MV vaccine plasmid had a level of MV-specific CTL activity among splenocytes that was comparable with levels observed in mice immunized by the i.p . route with attenuated Salmonella typhi harboring the same DNA vaccine plasmid, despite the fact that Shigella remained localized to the lungs, yet Salmonella disseminated to the spleen following inoculation . Thus, Deltaasd Shigella represents a very useful vector for delivery of DNA vaccines to mucosal lymphoid tissues.

J Immunol, 1999 Feb 1, 162(3), 1573 - 81
MHC class II-dependent NK1.1+ gammadelta T cells are induced in mice by Salmonella infection; Nishimura H et al.; We observed the emergence of a novel population of gammadelta T cells expressing NK1.1 Ag in the peritoneal cavity of mice infected with Salmonella choleraesuis . The NK1.1+gammadelta T cells accounted for approximately 20% of all gammadelta T cells emerging in the peritoneal cavity of C57BL/6 mice and expressed preferentially rearranged Vgamma4-Jgamma1 and Vdelta6.3-Ddelta1-Ddelta2-Jdelta1 genes with N diversity . The gammadelta T cells proliferated vigorously in response to PHA-treated spleen cells and produced IFN-gamma in the culture supernatant . However, spleen cells from Abetab-deficient mice were unable to stimulate the gammadelta T cells . Furthermore, the NK1.1+gammadelta T cells were stimulated not only by Chinese hamster ovary (CHO) cells expressing wild-type IAb but also by those expressing IAb/Ealpha52-68 or IAb/pigeon cytochrome c-derived analogue peptide complex . These proliferation activities were inhibited by mAb specific for IAb chain . Consistent with these findings, the emergence of NK1.1+gammadelta T cells was reduced in the peritoneal cavity of Abetab-deficient mice after Salmonella infection, whereas NK1.1+gammadelta T cells were rather abundant in the peritoneal cavity of Salmonella-infected beta2m-deficient mice . Moreover, the NK1.1+gammadelta T cells were easily identified in the thymus of beta2m-deficient but not Abetab-deficient mice . Our results indicated that MHC class II expression is essential for development and activation of NK1 . 1+gammadelta T cells in the thymus and the periphery.

J Bacteriol, 1999 Feb, 181(4), 1301 - 8
Analysis of the type 1 pilin gene cluster fim in Salmonella: its distinct evolutionary histories in the 5' and 3' regions; Boyd EF et al.; The type 1 pilin encoded by fim is present in both Escherichia coli and Salmonella natural isolates, but several lines of evidence indicate that similarities at the fim locus may be an example of independent acquisition rather than common ancestry . For example, the fim gene cluster is found at different chromosomal locations and with distinct gene orders in these closely related species . In this work we examined the fim gene cluster of Salmonella, the genes of which show high nucleotide sequence divergence from their E . coli counterparts, as well as a different G+C content and codon usage . DNA hybridization analysis revealed that, among the salmonellae, the fim gene cluster is present in all isolates of S . enterica but is absent from S . bongori . Molecular phylogenetic analyses of the fimA and fimI genes yield an estimate of phylogeny that is in satisfactory congruence with housekeeping and other virulence genes examined in this species . In contrast, phylogenetic analyses of the fimZ, fimY, and fimW genes indicate that horizontal transfer of this region has occurred more than once . There is also size variation in the fimZ, fimY, and fimW intergenic regions in the 3' region, and these genes are absent in isolate S2983 of subspecies IIIa . Interestingly, the G+C contents of the fimZ, fimY, and fimW genes are less than 46%, which is considerably lower than those of the other six genes of the fim cluster . This study demonstrates that horizontal transmission of all or part of the same gene cluster can occur repeatedly, with the result that different regions of a single gene cluster may have different evolutionary histories.

J Bacteriol, 1999 Feb, 181(4), 1264 - 8
Analysis of rpoS mRNA in Salmonella dublin: identification of multiple transcripts with growth-phase-dependent variation in transcript stability; Paesold G et al.; In Salmonella dublin, rpoS encodes an alternative sigma factor of the RNA polymerase that activates a variety of stationary-phase-induced genes, including some virulence-associated genes . In this work, we studied the regulation and transcriptional organization of rpoS during growth . We found two transcripts, 2.3 and 1.6 kb in length, that represent the complete rpoS sequence . The 2.3-kb transcript is a polycistronic message that also includes the upstream nlpD gene . It is driven by a weak promoter with increasing activity when cells enter early stationary growth . The 1.6-kb message includes 566 bp upstream of the rpoS start codon . It is transcribed from a strong sigma70 RNA polymerase-dependent promoter which is independent of growth . The decay of this transcript decreases substantially in early stationary growth, resulting in a significant net increase in rpoS mRNA levels . These levels are approximately 10-fold higher than the levels of the 2.3-kb mRNA, indicating that the 1.6-kb message is mainly responsible for RpoS upregulation . In addition to the 2.3- and 1.6-kb transcripts, two smaller 1.0- and 0.4-kb RNA species are produced from the nlpD-rpoS locus . They do not allow translation of full-length RpoS; hence their significance for rpoS regulation remains unclear . We conclude that of four transcripts arising from the nlpD-rpoS locus, only one plays a significant role in rpoS expression in S . dublin . Its upregulation when cells enter stationary growth is due primarily to an increase in transcript stability.

Recenti Prog Med, 1998 Dec, 89(12), 632 - 6
{Systemic Salmonella arizonae infections in patients with a deficiency of cell-mediated immunity . A report of 2 cases and a review of the literature}; Carfagna P et al.; Systemic infections induced by Salmonella arizonae have been described in patients with underlying cell-mediated immunodeficiencies, usually resident in southern countries of U.S . and in Mexico . This peculiar geographic distribution is probably due to the ingestion of meat or drugs from rattlesnakes, that Salmonella arizonae colonize in the intestinal tract and that live in the above areas . In this article we describe two cases of systemic Salmonella arizonae infections, that represent, to our knowledge, the first report in European literature.

Rev Neurol, 1998 Dec, 27(160), 986 - 7
{Meningitis due to Salmonella in the neonatal period}; Vazquez-Lopez ME et al.; INTRODUCTION: Meningitis due to Salmonella is an unusual sign of salmonellosis . Usually Salmonella causes clinical disorders of the digestive tract, but on occasions, especially in babies, may cause focalized infections such as meningitis . Although meningitis due to Salmonella is unusual, it should be remembered because of its gravity, since it has a high morbimortality . It mainly affects neonatal babies and those under 4 months of age . It usually precedes or is accompanied by gastroenteritis and has a rapid clinical course . CLINICAL CASE: We present the case of a neonatal baby girl, 17 days old, who was very irritable, had liquid or semi-liquid faeces and high fever of unknown origin with poor response to antipyretic drugs . On lumbar puncture a cloudy liquid, compatible with bacterial meningitis was obtained . Treatment was therefore started immediately with intravenous ampicillin and cefotaxima . CSF culture grew Salmonella which was resistant to ampicillin but sensitive to cefotaxima . Antibiotic treatment was given for 21 days . There was excellent clinical recovery . After eight months of follow-up no sequelae have been seen and her development, both psychomotor, in height and in weight is normal for her age . CONCLUSION: Meningitis due to Salmonella is an unusual condition . Immediate, suitable treatment is essential to obtain satisfactory recovery.

Vet Parasitol, 1999 Jan 14, 80(3), 179 - 85
Cryptosporidium and concurrent infections with other major enterophatogens in 1 to 30-day-old diarrheic dairy calves in central Spain; de la Fuente R et al.; Faeces samples from 218, 1 to 30-day-old, diarrheic dairy calves in 65 dairy herds were screened for the presence of Cryptosporidium and concurrent infections with rotavirus, coronavirus, F5 Escherichia coli and Salmonella spp . Calves were grouped according to their age as follows: 1-7, 8-14, 15-21 and 22-30 days . Cryptosporidium infection was detected in 43.8%, 71.9%, 63.2% and 6.9% of the calves in the respective age groups . Significant differences in the detection rate of Cryptosporidium were found between the age group 22-30 days and all other age groups, and between the age group 1-7 days and the age groups 8-14 days and 15-21 days . Cryptosporidium was the only enteropathogen detected in 60 of the 114 (52.6%) diarrheic calves . Concurrent infections with other enteropathogen(s) were detected in 64.3%, 46.3%, 39.5% and 0% of the Cryptosporidium-infected calves in the age groups 1-7, 8-14, 15-21 and 22-30 days, respectively . A significant age-associated decrease in the detection rate of mixed infections (p < 0.05) was found . The detection rates of the other enteropathogens considered in calves with Cryptosporidium infection were 87% for rotavirus, 11.1% for coronavirus, 27.8% for F5+ E . coli and 1.8% for Salmonella.

Rev Argent Microbiol, 1998 Oct-Dec, 30(4), 180 - 4
{Salmonella: comparison of methods for its detection in bird feed}; Lound L et al.; The Gene Trak colorimetric hybridization method (GENE TRAK Systems, 31 New York Avenue, Framingham, M.A.) was compared with conventional methodology proposed by International Commission for Microbiological Standard Foods (ICMSF) for the detection of Salmonella in samples of broiler feed and raw materials of vegetal and animal origin used in its formulation . In this study 249 samples which included inoculated samples and 9 uninoculated samples were studied . On 240 uninoculated samples, 62.9% resulted free of Salmonella, 27.9% were positive for both methods and 9.2% were positive by Gene Trak but it couldn't be confirmed by conventional methodology after five determinations . This methodology is presented as an interesting method of screening with important advantages in comparison to conventional methodology: facility for processing a big number of samples with few material expenses, less time to get results and high sensibility.

Zh Mikrobiol Epidemiol Immunobiol, 1998 Nov-Dec, (6), 20 - 3
{Immunosuppressive action of lipopolysaccharide S- and R-forms of Salmonella and the role of lipid A}; Borisova EV; The immunosuppressive activity of extracellular and water-phenol lipopolysaccharides (LPS) of S.minnesota in S- and R-forms, as well as their gel-filtration, polysaccharide and lipid fractions, was studied in mouse experiments on the model of delayed type hypersensitivity (DTH) . The study revealed that the extracellular LPS of S-form S.minnesota was capable of suppressing DTH with lipid A playing the decisive role in this immunosuppressive activity . The extracellular LPS of Reform S.minnesota did not possess the capacity for immunosuppression, but acquired it after redox treatment.

Parasitol Res, 1999 Feb, 85(2), 93 - 7
Soluble-protein and antigenic heterogeneity in axenic Blastocystis hominis isolates: pathogenic implications; Lanuza MD et al.; The protein profile and the antigenic cross-reactivity of 18 axenic isolates of Blastocystis hominis obtained from symptomatic patients with chronic diarrhea (14 isolates) showing no evidence of parasitic etiology and from patients with acute diarrhea attributable in 2 cases to Salmonella spp . were analyzed . Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of soluble proteins showed the existence of a common profile composed of 31 bands, with molecular weights ranging between 24 and >200 kDa, and minor differences in the proteins of 149, 118, 106, 50, 48, 47, and 30 kDa . These differences allowed us to classify the strains into three related patterns (I-III) . In an indirect immunofluorescence assay, all strains were serologically identical, but two related antigenic groups (1 and 2) were found in double-immunodiffusion and Western-blot studies . The isolates of protein patterns I and II belonging to antigenic group 1 were isolated from patients with chronic diarrhea, whereas the four isolates from patients with acute diarrhea were clustered in protein pattern III and in antigenic group 2 . These results confirm the protein and antigenic heterogeneity of B . hominis and the existence of demes with different pathogenic roles.

Planta Med, 1998 Dec, 64(8), 748 - 51
Structure-activity relationships of protoberberines having antimicrobial activity; Iwasa K et al.; 13-Alkyl derivatives (2-6 and 8-12) of berberine (1) and palmatine (7) were subjected to in vitro antibacterial activity tests against Bacillus subtilis and Salmonella enteritidis . Antibacterial activity increased as the length of the C-13 aliphatic side chain increased . The effects of the oxygen-substituents on aromatic rings A, C, and D of protoberberinium salts 13-20 on the antimicrobial activity against Staphylococcus aureus, B . subtilis, S . enteritidis, Escherichia coli, and Candida albicans are also discussed . The change in lipophilicity of the protoberberinium salts caused by modification of the substituents appears to influence the antibacterial activity . 13-Hexylberberine (6) and 13-hexylpalmatine (12) exhibited the greatest antibacterial activity.

Nat Med, 1999 Feb, 5(2), 183 - 8
Molecular basis for resistance to silver cations in Salmonella; Gupta A et al.; Here we report the genetic and proposed molecular basis for silver resistance in pathogenic microorganisms . The silver resistance determinant from a hospital burn ward Salmonella plasmid contains nine open reading frames, arranged in three measured and divergently transcribed RNAs . The resistance determinant encodes a periplasmic silver-specific binding protein (SilE) plus apparently two parallel efflux pumps: one, a P-type ATPase (SilP); the other, a membrane potential-dependent three-polypeptide cation/proton antiporter (SilCBA) . The sil determinant is governed by a two-component membrane sensor and transcriptional responder comprising silS and silR, which are co-transcribed . The availability of the sil silver-resistance determinant will be the basis for mechanistic molecular and biochemical studies as well as molecular epidemiology of silver resistance in clinical settings in which silver is used as a biocide.

J Membr Biol, 1999 Feb 1, 167(3), 223 - 32
Complement activation by bacterial surface glycolipids: a study with planar bilayer membranes; Munstermann M et al.; Planar asymmetric glycolipid/phospholipid bilayer membranes were used as a reconstitution model of the lipid matrix of the outer membrane of Gram-negative bacteria to study complement (C) activation by various bacterial surface glycolipids with the aim of defining the C activation pathway . As glycolipids the lipopolysaccharides of Salmonella enterica serovar Minnesota R mutant strains R595 (Re LPS) and R4 (Rd2 LPS), pentaacyl lipid A from the LPS of the Escherichia coli Re mutant F515, and glycosphingolipid GSL-1 of Sphingomonas paucimobilis IAM 12576 were used . Methylester and carboxyl-reduced derivatives of GSL-1 were used to elucidate the role of the carboxyl group as common functional group of LPS and GSL-1 for C activation . The formation of lytic pores was monitored via the measurement of changes in membrane current . For all glycolipids we observed a considerable increase in membrane current soon after addition of whole human serum due to the formation of lytic pores in the membranes . Pore formation was dependent on the presence of C9, indicating that the observed current changes were due to C activation . We found that in our reconstitution system of the outer membrane lipid A, Re LPS, and Rd2 LPS activated the classical pathway, the activation being independent of specific anti-LPS antibodies . In contrast, GSL-1 and the methylester derivative of GSL-1 activated the alternative pathway even at the low serum concentrations used in this study (about 0.2% v/v) . Interestingly, the carboxyl reduced GSL-1 activated the classical pathway.

Regul Toxicol Pharmacol, 1998 Oct, 28(2), 85 - 95
Identification of rodent carcinogens and noncarcinogens using genetic toxicity tests: premises, promises, and performance; Zeiger E; The basic premises that guide genetic toxicity testing for identifying carcinogens and to support administrative and regulatory decisions are: the Salmonella mutagenicity test is a necessary component of testing schemes; a chromosome aberration test is needed in addition to a gene mutation test; a mammalian cell mutagenicity test is needed in addition to the Salmonella test; in vivo tests are needed to confirm the results of in vitro tests; and test batteries are more predictive than the individual tests of the battery . Results from the Salmonella mutagenicity, in vitro chromosome aberration, mutations in mouse lymphoma cells, rodent bone marrow micronucleus, and rodent carcinogenicity tests, performed by the U.S . National Toxicology Program, were used to evaluate these premises . A positive Salmonella test was most predictive of carcinogenicity . However, the data do not support using the other tests in addition to Salmonella for predicting carcinogenicity . The genetic toxicity tests did not complement each other, and batteries or combinations of the tests were no more predictive of carcinogenicity than Salmonella alone . If a chemical is mutagenic in Salmonella it should be considered a potential rodent carcinogen, unless ancillary information suggests otherwise . Positive responses in the other in vitro or in vivo tests do not increase the probability that the chemical is a carcinogen, and negative responses in the other tests do not diminish the implications of the positive Salmonella response.

Int J Food Microbiol, 1998 Dec 22, 45(3), 205 - 10
Comparison between ICS-Vidas, MSRV and standard cultural method for Salmonella recovery in poultry meat; De Medici D et al.; Two rapid methods for Salmonella detection, Vidas-ICS and modified semi-solid Rappaport-Vassiliadis (MSRV) were evaluated using contaminated poultry meat . The sensitivity and specificity of the methods were investigated on field samples and on artificially contaminated samples inoculated with mixtures of Salmonella and non-Salmonella competing strains . ICS-Vidas and MSRV yielded virtually identical results, in full agreement with the standard cultural method (SCM) . The MSRV method showed better results with artificially contaminated samples, but was less sensitive than SCM when applied to field samples . The use of the MSRV and Vidas-ICS methods could be particularly advantageous in the application of HACCP.

Ann Trop Paediatr, 1998 Dec, 18(4), 275 - 8
Bacteraemia in cerebral malaria; Enwere G et al.; As part of a treatment trial of cerebral malaria, blood cultures were done in 276 Gambian children, aged between 1 and 9 years, with cerebral malaria . Fourteen (5%) of these were positive . The organisms isolated were Staphylococcus aureus (6), coliforms (4), Pseudomonas spp . (2), Salmonella spp . (1) and Streptococcus spp . (1) . Thirteen of these children survived, most without appropriate antibiotic treatment . Most of the retrieved organisms were therefore suspected to be contaminants . Bacteraemia complicating cerebral malaria is not common in The Gambia, and routine antibiotic treatment of children with cerebral malaria is not warranted.

Environ Health Perspect, 1999 Feb, 107(2), 129 - 32
Relationship between allergic contact dermatitis and electrophilicity; Rosenkranz HS et al.; To evaluate the role of electrophilicity in the induction of allergic contact dermatitis (ACD) in humans, we compared the structure-activity relationship (SAR) model of ACD with those of electrophilic and nonelectrophilic subsets of chemicals in the ACD database . For these analyses, electrophilicity was defined as the potential of a chemical to induce mutations in Salmonella . It was found that electrophilicity accounted for approximately 30-40% of ACD-inducing ability, and the remainder was associated with nonelectrophilic structures . The identification of these moieties opens the possibility for studying their role in ACD.

Int J Food Microbiol, 1998 Nov 24, 45(1), 25 - 8
AOAC validation of qualitative and quantitative methods for microbiology in foods . Association of Official Agricultural Chemists; De Smedt JM; The purpose of AOAC International is promoting quality measurements and methods validation in the analytical sciences . The actual work of developing and testing methods is done by a network of AOAC members and volunteers . Validation of the methods is established by the AOAC Official Methods Program . The objective of this program is to provide analytical methods for which performance characteristics have been validated to the highest degree of confidence through an independent, multiple laboratory collaborative study . The performance characteristics for quantitative microbiological methods include repeatability, reproducibility and critical relative difference, while the characteristics for qualitative methods are sensitivity and specificity . The Official Methods Program is illustrated by a practical example of a collaborative study through which salmonella detection by motility enrichment on Modified Semi-solid Rappaport-Vassiliadis (MSRV) medium was adopted as an Official Method.

Eur J Clin Microbiol Infect Dis, 1998 Nov, 17(11), 791 - 3
Evaluation of methods for isolation of Salmonella species using modified semisolid Rappaport-Vassiliadis medium and Salmonella-Shigella agar; Ruiz Gomez J et al.; A total of 197 Salmonella strains were isolated from 1717 stool samples on salmonella-shigella agar and modified semisolid Rappaport-Vassiliadis medium before and after enrichment in selenite broth . Better sensitivity was obtained with salmonella-shigella agar than in direct plating (89.2% vs . 64.4%, P<0.0001) and after broth enrichment (96.4% vs . 88.1%, P<0.01) . The incidence of false-positive results using modified semisolid Rappaport-Vassiliadis medium was higher than that obtained using salmonella-shigella agar combined with the oxidase and C8 esterase tests in direct plating (33 vs . 2 strains) and after enrichment (43 vs . 0 strains) . Thus, based on its performance modified semisolid Rappaport-Vassiliadis medium could be a suitable option for isolation of salmonellae from stool samples in clinical microbiology laboratories.

J Bacteriol, 1999 Feb, 181(3), 998 - 1004
The SPI-3 pathogenicity island of Salmonella enterica; Blanc-Potard AB et al.; Pathogenicity islands are chromosomal clusters of pathogen-specific virulence genes often found at tRNA loci . We have determined the molecular genetic structure of SPI-3, a 17-kb pathogenicity island located at the selC tRNA locus of Salmonella enterica serovar Typhimurium . The G+C content of SPI-3 (47.5%) differs from that of the Salmonella genome (52%), consistent with the notion that these sequences have been horizontally acquired . SPI-3 harbors 10 open reading frames organized in six transcriptional units, which include the previously described mgtCB operon encoding the macrophage survival protein MgtC and the Mg2+ transporter MgtB . Among the newly identified open reading frames, one exhibits sequence similarity to the ToxR regulatory protein of Vibrio cholerae and one is similar to the AIDA-I adhesin of enteropathogenic Escherichia coli . The distribution of SPI-3 sequences varies among the salmonellae: the right end of the island, which harbors the virulence gene mgtC, is present in all eight subspecies of Salmonella; however, a four-gene cluster at the center of SPI-3 is found in only some of the subspecies and is bracketed by remnants of insertion sequences, suggesting a multistep process in the evolution of SPI-3 sequences.

J Food Prot, 1999 Jan, 62(1), 26 - 9
Cheesecake: a potential vehicle for salmonellosis?
Hao YY, Scouten AJ, Brackett RE.
This study was conducted to investigate the potential hazard of Salmonella Enteritidis surviving during the preparation and baking of cheesecake . Batters prepared with standard- and reduced-fat ingredients were inoculated with a 5-strain cocktail of S . Enteritidis (10 and 10(6) CFU/g) and were then baked according to a typical cheesecake recipe . After baking, the cheesecakes were refrigerated overnight before the survival of S . Enteritidis was determined either by direct plating or after enrichment . Samples (approximately 25 g each) were aseptically cut from the center, mid (6.35 cm from edge), and side (2.54 cm from edge) area of each cake for microbiological analysis . Proximate compositions (fat, moisture, protein, ash, pH, and water activity) of both raw batter and final baked cheesecakes were also determined . S . Enteritidis was able to survive baking of cheesecake when batter was inoculated with a high population (10(6) CFU/g) of S . Enteritidis regardless of whether standard-or reduced-fat ingredients were used . Three of nine standard- and four of nine reduced-fat cheesecake samples contained viable S . Enteritidis . In addition, one sample contained viable S . Enteritidis population detectable by direct plating (approximately 10 CFU per g of cake) . This sample was taken from the center of a standard-fat cheesecake that was inoculated with a high population (10(6) CFU/g) of S . Enteritidis . Results of this study suggest that cheesecake prepared with eggs of low microbiological quality or cheesecake improperly handled or stored could serve as a vehicle for salmonellosis.

J Food Prot, 1999 Jan, 62(1), 22 - 5
Prevalence of Salmonella spp . and Yersinia enterocolitica in finishing swine at Canadian abattoirs; Letellier A et al.; The prevalence of Salmonella spp . and Yersinia enterocolitica in finishing swine was evaluated using samples of cecal material . Samples were taken at six different slaughterhouses from 1420 healthy, 5-month-old pigs, raised by 223 producers in Quebec (1009 samples), Ontario (283), and Manitoba, Canada (128) . Two different broth media (Rappaport-Vassiliadis and Tetrathionate brilliant green) were used for the selective enrichment of Salmonella spp . The recovery of Y . enterocolitica was done by a cold enrichment technique, followed by plating on a selective media (cefsulodin-irgasan-novobiocin agar) . Prevalence (with a 95% confidence interval) of Salmonella spp . and Y . enterocolitica were, respectively, 5.2% (4.0 to 6.4%) and 20.9% (18.8 to 23.0%) . Overall, 24.6% of the animals tested were positive for one or both of these pathogens . Since only a few herds (2.8%) appeared to be highly contaminated by Salmonella spp., efforts should be undertaken in priority to control this pathogen in those herds.

J Food Prot, 1999 Jan, 62(1), 16 - 21
Relative effectiveness of selenite cystine broth, tetrathionate broth, and Rappaport-Vassiliadis medium for the recovery of Salmonella spp . from foods with a low microbial load; Hammack TS et al.; The relative effectiveness of Rappaport-Vassiliadis (RV) medium, selenite cystine (SC) broth, and tetrathionate (TT) broth for the recovery of Salmonella spp . from foods with a low microbial load was determined . RV medium made from its individual ingredients and incubated at 42 degrees C was compared with a commercial preparation of SC broth, incubated at 35 degrees C, and TT broth incubated at 35 and 43 degrees C, for the recovery of Salmonella spp . Twenty-one artificially contaminated food types that included dairy foods, spices, and egg products, as well as other low-microbial-load foods, were analyzed . The foods were inoculated with single Salmonella serovars at target levels ranging from 0.04 to 0.4 CFU/g . No significant differences (P< or =0.05) among the selective enrichment broths for the recovery of Salmonella spp . from 18 of the foods were observed . Significantly fewer Salmonella-positive test portions of gelatin, guar gum, and nonfat dry milk were recovered with RV medium than with SC broth incubated at 35 degrees C and TT broth incubated at 35 and 43 degrees C . TT broth incubated at 35 degrees C recovered the greatest number of Salmonella-positive test portions . For the recovery of Salmonella spp . from foods with a low microbial load, it is recommended that TT broth incubated at 35 degrees C and RV medium incubated at 42 degrees C be used.

Shock, 1999 Jan, 11(1), 35 - 8
The effect of a tyrosine kinase inhibitor on endotoxin mortality and splenocyte mediator production in the neonatal rat; Cochran JB et al.; Tyrosine kinases mediate cellular signal transduction to endotoxin . A class of tyrosine kinase inhibitors, the tyrphostins, have been shown to protect mice from endotoxin-induced lethality . Neonatal rats and mice have been shown to be uniquely susceptible to lethal endotoxic shock . In our study, the effect of a lipophilic tyrphostin, AG 556, on endotoxin-induced neonatal and adult mortality and in vitro neonatal splenic cell thromboxane (TxB2), tumor necrosis factor-alpha (TNF-alpha), and nitric oxide (NO) production were examined . Neonatal rats (<24 h old) were administered tyrphostin (100 microg subcutaneous) 2 h before an approximate LD50 dose of Salmonella enteritidis endotoxin (.024 mg/kg/intracardiac) . There was a significant decrease in mortality in the animals pretreated with 100 microg of tyrphostin (29% mortality in the treated group, n = 41 versus 53% in the vehicle control group, n = 40; p < .05) . Also in adult rats tyrphostin (5 mg/kg intraperitoneal) 2 h before endotoxin (10 mg/kg intravenous) significantly improved survival (50% drug treated versus 84% in control, n = 12/group; p < .05) . Adherent neonatal splenic cell mediator production of TxB2, TNF-alpha, and NO (measured by nitrite) in tyrphostin pretreated splenic cells were compared with endotoxin-stimulated splenic cells in vitro . The studies (n = 4) demonstrate an increase (p < .05) in the production of TxB2, TNF-alpha, and NO in the endotoxin- (10 microg/mL) stimulated adherent splenic cells compared with basal . Tyrphostin pretreatment (10, 20, 50 microM) produced a dose-dependent decrease (p < .05) in endotoxin-stimulated TxB2 and TNF-alpha production . NO production was not significantly reduced . In conclusion, tryphostin appears to have a protective effect on mortality in both adult and neonatal rat endotoxic shock . Tyrphostin decreased specific mediator production in stimulated neonatal cells . Thus, inhibition of signal transduction pathways of endotoxin activation by tyrosine kinase inhibition may provide an effective approach to treat endotoxic shock in the neonate.

Mem Inst Oswaldo Cruz, 1998, 93 Suppl 1, 135 - 9
Schistosomiasis and associated infections; Lambertucci JR et al.; In hospital-based series viral hepatitis B has been frequently described in association with schistosomiasis whilst in field-based studies the association has not been confirmed . The association between schistosomiasis and Salmonella bacteraemia has been well documented . More recently, acute schistosomiasis has been shown to be a facilitating factor in the genesis of pyogenic liver abscesses caused by Staphylococcus aureus . New evidences indicate an interaction between the acquired immunodeficiency syndrome (AIDS) and schistosomiasis . In this paper, data on the association of schistosomiasis with other infections are updated.

Nat Biotechnol, 1999 Jan, 17(1), 37 - 41
Lipid A mutant Salmonella with suppressed virulence and TNFalpha induction retain tumor-targeting in vivo; Low KB et al.; Systemically administered tumor-targeted Salmonella has been developed as an anticancer agent, although its use could be limited by the potential induction of tumor necrosis factor alpha (TNFalpha)-mediated septic shock stimulated by lipid A . Genetic modifications of tumor-targeting Salmonella that alter lipid A and increase safety must, however, retain the useful properties of this bacteria . We report here that disruption of the Salmonella msbB gene reduces TNFalpha induction and increases the LD50 of this pathogenic bacteria by 10,000-fold . Notwithstanding this enormous difference, Salmonella retains its tumor-targeting properties, exhibiting tumor accumulation ratios in excess of 1000:1 compared with normal tissues . Administration of this bacteria to mice bearing melanoma results in tumors that are less than 6% the size of tumors in untreated controls at day 18 . Thus, the antitumor activity previously demonstrated using tumor-targeting Salmonella with normal lipid A is retained . Lipid modification of tumor-specific bacterial vectors provides a means for reducing septic shock and further suggests that the antitumor activity of these bacteria may be independent of TNFalpha.

J Med Microbiol, 1999 Jan, 48(1), 79 - 88
Induction of systemic and mucosal immune response in mice immunised with porins of Salmonella typhi; Singh M et al.; Porins, purified from Salmonella typhi strain 0901 provided 90% protection to BALB/c mice against a lethal dose (300 x LD50) of S . typhi Ty2 when given intraperitoneally . To measure the porin-induced cellular immune responses, macrophages and lymphocytes were isolated from spleen and lamina propria (LP) of porin immunised-challenge mice and of infected and control mice; T-cell phenotypes, lymphocyte proliferation and cytokine production were studied . The secretory IgA (sIgA) antibody level in the intestinal fluid was also measured to study mucosal immune response . After immunisation, the splenic lymphocytes exhibited a significant increase in total T-cell count and CD4+/CD8+ ratio, while the LP lymphocytes (LPL) exhibited an increase in CD4+/CD8+ ratio only . They also exhibited a significant increase in porin-specific proliferative response and cytokine levels (IL-1, IL-2, IFN-gamma and IL-4) . After immunisation, sIgA antibody was also found to be increased . These results suggest that porins given intraperitoneally induce cellular and humoral immune responses both at systemic and mucosal levels.

Arthritis Rheum, 1999 Jan, 42(1), 84 - 9
Salmonella-triggered reactive arthritis: use of polymerase chain reaction, immunocytochemical staining, and gas chromatography-mass spectrometry in the detection of bacterial components from synovial fluid; Nikkari S et al.; OBJECTIVE: To investigate whether microbial components are present in the cells of synovial fluid or peripheral blood from patients with Salmonella-triggered reactive arthritis (ReA) . METHODS: Synovial fluid cells and/or peripheral blood cells from 23 patients with Salmonella-triggered ReA and from 19 control patients with newly diagnosed rheumatoid arthritis were studied using 3 different polymerase chain reaction (PCR) techniques and immunocytochemical staining . Muramic acid from the synovial fluid was studied by gas chromatography-mass spectrometry . RESULTS: Salmonella chromosomal DNA was not detectable in the synovial fluid cells and peripheral blood leukocytes of patients with Salmonella ReA . Initially, positive reactions were observed in the synovial fluid cells and peripheral blood leukocytes of 3 of 17 and 3 of 18 patients with ReA, respectively, but in the subsequent PCR studies, these findings were not reproducible . Salmonella-specific antigen was detectable by immunofluorescence in the synovial fluid cells and peripheral blood leukocytes of 4 of 11 and 2 of 7 patients with ReA, respectively . Muramic acid was present in 2 of 15 synovial fluid samples from patients with ReA, but the bacterial cultures from synovial fluid were negative . CONCLUSION: These findings indicate the presence of bacterial degradation products, but not bacterial DNA, in the inflamed joints of patients with Salmonella-triggered ReA.

Przegl Epidemiol, 1998, 52(3), 263 - 7
{Registration of the foodborne diseases in Poland in 1919-1997}; Przybylska A; The aim of this paper was presenting of the history of registration of the foodborne and waterborne diseases in Poland, as well as describing of the epidemiological situation of these diseases . In the years between the I and II World Wars and from 1945 to 1947 enteric fever and bacterial dysentery were most often registered . From 1951 began the increasing of the total numbers of cases of the viral hepatitis with the peak of diseases in 1964 (about 125,000 cases) . The years 80s were characterized by the increasing number of cases caused by Salmonella of animal's source with the peak in 1988 (about 62,000 cases) . In the years 90s the decrease of the number of salmonelloses of animal's source occurred.

Epidemiol Mikrobiol Imunol, 1998 Dec, 47(4), 166 - 8
{An epidemic of salmonellosis in the First League Hockey Team}; Cerny Z et al.; The authors describe an epidemic of salmonellosis in 27 players and officials of the first league hockey team HC Kometa Brno which developed in conjunction with the consumption of a lunch in the facilities where the team usually takes its meals before competitions . The disease affected without exception all participants of the lunch, had a very severe course with high temperatures, weakness and intense diarrhoea sometimes with vomiting . The disease persisted for 3-6 days, the loss of body weight caused mainly by dehydration was 4 to 13 kg . Faeces samples (3) of all affected patients were during the acute stage of the disease bacteriologically positive . Spontaneous debacilization took with a single exception 2-4 weeks . The disease was caused by Salmonella enteritidis, phagotype 8 . The source was not detected and the vehicle was most probably secondarily contaminated soup.

FEMS Microbiol Lett, 1999 Jan 1, 170(1), 257 - 64
Viable, but non-culturable, state of a green fluorescence protein-tagged environmental isolate of Salmonella typhi in groundwater and pond water; Cho JC et al.; An environmental isolate of Salmonella typhi was chromosomally marked with a gfp gene encoding green fluorescence protein (GFP) isolated from Aequorea victoria . The hybrid transposon mini Tn5 gfp was transconjugated from E . coli to S . typhi, resulting in constitutive GFP production . The survival of S . typhi GFP155 introduced into groundwater and pond water microcosms was examined by GFP-based plate counts, total cell counts, and direct viable counts . A comparison between GFP-based direct viable counts and plate counts was a good method for verifying the viable, but non-culturable (VBNC), state of S . typhi . The entry into a VBNC state of S . typhi was shown in all microcosms . S . typhi survived longer in groundwater than in pond water as both a culturable and a VBNC state.

FEMS Microbiol Lett, 1999 Jan 1, 170(1), 141 - 3
The rpoS mutant allele of Salmonella typhi Ty2 is identical to that of the live typhoid vaccine Ty21a; Robbe-Saule V et al.; Salmonella requires its alternative sigma factor sigma S (RpoS) for virulence in mice . rpoS mutants can be frequently isolated from highly passaged Salmonella laboratory strains . In particular, the live typhoid oral vaccine Salmonella typhi Ty21a and its parental strain Ty2, a 'wild-type' strain widely used for vaccine development, are rpoS mutants . Here, we show that the nucleotide sequence of the rpoS mutant allele of Ty2 is identical to that of the rpoS mutant allele of Ty21a . This demonstrates that the rpoS mutation arose in Ty2 before the isolation of Ty21a in 1975, an observation that may have implications for vaccine research.

J Diarrhoeal Dis Res, 1998 Sep, 16(3), 201 - 4
An outbreak of food poisoning associated with restaurant-made mayonnaise in Abha, Saudi Arabia; al-Ahmadi KS et al.; In May 1996, an outbreak of gastroenteritis occurred among customers who bought dinner from a restaurant that specialised in fried chicken in Abha city, south-west Saudi Arabia . The median incubation period was 10 hours (range: 3 to 27 hours) . Of the 10 food items served, only mayonnaise (RR 2.52; 95% CI 1.71-3.73) and minced garlic (RR 1.20; 95% CI 1.02-1.41) were associated with cases . Salmonella enterica was isolated from 124 (84%) of the 159 persons with symptoms of food poisoning, and 91 (73%) were serogroup Enteritidis, phage type B 14 . Mayonnaise was prepared in the restaurant using a regular blender . Minced garlic was prepared with the same blender immediately after making the mayonnaise . Unsafe storage of the mayonnaise at room temperature for a median of 6 hours could have resulted in overgrowth of bacteria and a high infective dose of bacteria per serving.

J Diarrhoeal Dis Res, 1998 Sep, 16(3), 180 - 6
Serogroups and antimicrobial susceptibility of clinical isolates of Salmonella species from a teaching hospital in Kuwait; Jamal WY et al.; Salmonella strains isolated in a teaching-cum-general hospital in Kuwait during 1990-1993 and 1996 were analysed to determine the trend in the prevalence of the serogroups and their changing pattern of susceptibility . The records were reviewed for all the 661 isolates encountered during these periods . The most prevalent serogroup in both children and adults was serogroup B, followed by serogroup C and D . A sizeable proportion of the strains were resistant to first-line drugs . About 39% of the isolates were resistant to ampicillin, 17% to co-trimoxazole, 13% to chloramphenicol, and 15% to cephalothin . The majority were, however, susceptible to the other drugs with low to very low resistance rates: 7% to amoxicillin/clavulanic acid, and 0.3% to cefotaxime . All the strains were susceptible to ciprofloxacin . In all, resistant strains were more prevalent among children than adults.

Int J Mol Med, 1999 Feb, 3(2), 169 - 74
DNA damage induced by Salmonella test-negative carcinogens through the formation of oxygen and nitrogen-derived reactive species (review); Kawanishi S et al.; High levels of active oxygen species generated by carcinogenic chemicals can cause DNA damage, which may lead to carcinogenesis . We have investigated the characteristics and mechanisms of DNA damage induced by some carcinogens . Here we show our experimental results and propose the possible mechanisms of DNA damage through a) NADH-dependent and b) manganese-dependent formation of reactive oxygen species . We also discuss the mechanism of c) DNA damage induced by nitric oxide and peroxynitrite.

Pediatrics . 1999 Jan;103(1):E1.
The home environment and salmonellosis in children; Schutze GE et al.; OBJECTIVE: To explore the role of foods and the home environment in the development of Salmonella infections in infants and children . METHODS: Home investigations were conducted of patients younger than 4 years of age infected with Salmonella . Cultures were obtained from foods, persons residing in the home, animals/pets/insects, and environmental sources . Like serotypes encountered in the index patients and isolates from the home underwent typing with pulsed-field gel electrophoresis . RESULTS: Home inspections were conducted in approximately 66% of eligible homes on the average of 3.4 days after the confirmation of the Salmonella isolate . A total of 526 cultures from 50 homes were obtained from foods (120), household members (73), refrigerators (52), water (47), countertops (46), soil (42), can-openers (36), vacuum cleaners (34), animals/pets/insects (26), and others (50) . Isolates with a serotype identical to those in the index patient were found in 16 homes, 3 of which included an isolate of a second serotype, and an isolate of a different serotype was recovered in 3 homes . The pulsed-field gel electrophoresis patterns of the isolates of identical serotypes from the subjects and from their environment were indistinguishable in all but 2 patients . Among isolates of the same serotype encountered in different homes, all patterns were different . The identical serotype was found in multiple locations (4), dirt surrounding front doors (4), household members (3), vacuum cleaner (1), animals/pets/insects (1), and a refrigerator shelf (1) . CONCLUSIONS: These data illustrate the importance of the child's environment in the development of salmonellosis . Clinicians should concentrate on educating the parents about the environmental spread of Salmonella . Contaminated foods in the home play a less significant role in the infection of infants and children.

JAMA, 1999 Jan 13, 281(2), 158 - 62
Multinational outbreak of Salmonella enterica serotype Newport infections due to contaminated alfalfa sprouts; Van Beneden CA et al.; CONTEXT: In December 1995, reported Salmonella enterica serotype Newport (SN) infections increased sharply in Oregon and British Columbia but not elsewhere in North America . Similar unexplained increases had been noted in 6 other states in the fall of 1995 . OBJECTIVE: To determine the source of the outbreak(s) . DESIGN: Case-control studies, environmental investigations, bacterial subtyping, and surveillance information review . SETTINGS: Oregon and British Columbia communities (winter 1995-1996) and Georgia, Oklahoma, Pennsylvania, Vermont, Virginia, and West Virginia (fall 1995) . PARTICIPANTS: Oregon and British Columbia residents with culture-confirmed SN infections and onset from December 1, 1995, through February 29, 1996, and healthy community controls . MAIN OUTCOME MEASURES: Odds ratio (OR) of illness associated with exposures; distribution patterns and culture of alfalfa seeds and sprouts; subtyping of SN isolates . RESULTS: We identified 133 cases in Oregon and British Columbia; 124 (93%) occurred in patients older than 18 years; 87 (65%) were female . Case patients were more likely than community control subjects to report having eaten alfalfa sprouts in the 5 days preceding illness (41% {17/41} vs 4% {3/75}; OR, 17.0; 95% confidence interval, 4.3-96.0) . Case isolates shared a distinctive pulsed-field gel electrophoresis (PFGE) pattern . The SN was grown from seeds and alfalfa sprouts . The distribution of 1 seed lot to multiple growers corresponded to the distribution of cases . Distribution of a second seed lot from the same European wholesaler corresponded to the location of the fall outbreak, which was characterized by a similar demographic profile . The PFGE pattern of fall outbreak isolates and confiscated sprouts and seeds was indistinguishable from the Oregon and British Columbia outbreak and differed from background isolates . CONCLUSIONS: The SN-contaminated alfalfa seeds were distributed to multiple growers across North America in 1995 and resulted in a protracted international outbreak scattered over many months . Current sprouting methods are inadequate to protect consumers from such events . Alfalfa sprouts may be an elusive but important vehicle for salmonellosis and other enteric infections.

Zentralbl Hyg Umweltmed, 1998 Dec, 201(4-5), 431 - 6
Inactivation of Salmonella during microwave cooking; Levre E et al.; Sixty meat loaves were experimentally infected with a strain of Salmonella serovar mbandaka to give approximately 10(7) cells/g . Thirty contaminated loaves were cooked in a microwave oven for 4 min, and 30 other samples for 3 min 30 s, both followed by a standing time of 2 min . No viable experimental contaminants were recovered from both core and surface samples of the 30 loaves cooked for 4 min . Loaves cooked for the short time were often Salmonella positive . These results point out that infection hazard linked to microwave cooked food can be avoided by following adequate procedures concerning exposure time, temperature and post-heating holding time . A standardization of microwave ovens for domestic use is desirable, making it easier to give users correct instructions based on careful and strict experimentations approved by Public Health Authorities.

Infect Immun, 1999 Feb, 67(2), 998 - 1003
All accessible epitopes in the Salmonella lipopolysaccharide core are associated with branch residues; Nnalue NA; Antisera generated against each of the nine known chemotypes of Salmonella lipopolysaccharide (LPS) core were characterized in order to delineate cross-reactive epitopes and define the bases for their accessibility . Strongly cross-reactive epitopes were associated with three chemotypes: Ra and Rb4, which recognized alpha-GlcNAc-1-->2-alpha-Glc, and Rd1, which recognized L-alpha-D-heptose-1-->7-L-alpha-D-heptose . Both these disaccharides and the more weakly cross-reactive alpha-Gal-1-->6-alpha-Glc terminal in Rb3 LPS represent branch points along the core oligosaccharide . Therefore, branch points in endotoxin core oligosaccharides may generally be cross-reactive.

Infect Immun, 1999 Feb, 67(2), 700 - 7
Characterization of candidate live oral Salmonella typhi vaccine strains harboring defined mutations in aroA, aroC, and htrA; Lowe DC et al.; The properties of two candidate Salmonella typhi-based live oral typhoid vaccine strains, BRD691 (S . typhi Ty2 harboring mutations in aroA and aroC) and BRD1116 (S . typhi Ty2 harboring mutations in aroA, aroC, and htrA), were compared in a number of in vitro and in vivo assays . BRD1116 exhibited an increased susceptibility to oxidative stress compared with BRD691, but both strains were equally resistant to heat shock . Both strains showed a similar ability to invade Caco-2 and HT-29 epithelial cells and U937 macrophage-like cells, but BRD1116 was less efficient at surviving in epithelial cells than BRD691 . BRD1116 and BRD691 were equally susceptible to intracellular killing within U937 cells . Similar findings were demonstrated in vivo, with BRD1116 being less able to survive and translocate to secondary sites of infection when inoculated into the lumen of human intestinal xenografts in SCID mice . However, translocation of BRD1116 to spleens and livers in SCID mice occurred as efficiently as that of BRD691 when inoculated intraperitonally . The ability of BRD1116 to increase the secretion of interleukin-8 following infection of HT-29 epithelial cells was comparable to that of BRD691 . Therefore, loss of the HtrA protease in S . typhi does not seem to alter its ability to invade epithelial cells or macrophages or to induce proinflammatory cytokines such as IL-8 but significantly reduces intracellular survival in human intestinal epithelial cells in vitro and in vivo.

Anaesthesist, 1998 Nov, 47 Suppl 1, S77 - 86
{Occupational exposure and environmental pollution: the role of inhalation anesthetics with special consideration of sevoflurane}; Hobbhahn J et al.; There are a number of assays available to study genetic toxicity of inhalation anaesthetics . Those discussed in this review are the Ames Salmonella mutagenesis test and assays for structural chromosome aberrations, micronuclei (MN) and sister chromatid exchanges (SCEs) . None of these assays showed abnormalities induced by volatile inhalation anaesthetics . Only Compound A induced a slight increase in the number of SCEs . However, the implications of this in vitro study are unclear . Results of studies focussing on the effects of long-term occupational exposure to inhalation anaesthetics are controversial . Neither harmfulness nor safety of chronic exposure to low concentrations of inhalation anaesthetics have been proven . Although there is no clear evidence of harmfulness, there is general agreement that occupational exposure should be minimized for precautionary reasons . This particularly applies to N2O . Therefore, occupational exposure standards have been established in many countries, though not yet for sevoflurane and desflurane . In Germany, occupational exposure can be kept below the threshold values, when working in operation theatres with a standard air conditioning system, a high-flow scavenging system, low leakage anaesthesia machines and preventative maintenance of equipment . Under these conditions occupational exposure is low even when using laryngeal mask airways and uncuffed tracheal tubes . Sevoflurane is a halocarbon, but is only partially halogenated and the only halogen it contains is fluorine . Sevoflurane, therefore, appears to have an insignificant effect on ozone depletion and its contribution to the greenhouse effect is negligible.

Genes Cells, 1998 Oct, 3(10), 625 - 34
Bacterial flagellation and cell division; Aizawa SI et al.; The peritrichous flagella of Salmonella are synthesized and function through many cell generations . There are two different aspects in the relationship between flagellar biogenesis and cell division . Filament growth is independent from the cell cycle and the length of filaments appear to be locally controlled at each flagellar base, whereas the number of filaments (or flagellar basal bodies) is dependent on cell cycle . We present a model to explain how the number of filaments is maintained through generations . We will also introduce a new direction for research that might directly connect flagellation and cell division; the global communication between flagellar genes and external factors of a complex regulatory network in a cell.

Adv Vet Med, 1999, 41, 257 - 73
Vaccines and diagnostic methods for bovine mastitis: fact and fiction; Yancey RJ Jr; A number of problems are uniquely associated with vaccination of dairy cows for mastitis . One of these is that the number of mastitis pathogens is numerous and heterogeneous . Vaccine efforts have concentrated mainly on the major mastitis pathogens . While at least one S . aureus bacterin has been commercially available for a number of years, no large-scale, independent field trials have been published in refereed journals which support the efficacy of this vaccine . Experimental vaccines for S . aureus composed of pseudocapsule-enriched bacterins supplemented with alpha- and/or beta-toxoids appear promising, but none of these has been commercialized . With S . uberis, some protection against homologous strain challenges was reported recently with a live strain and a bacterin, but other data from the same laboratory showed this vaccine would not protect against heterologous challenge strains . At this time there is only one highly effective vaccine for mastitis, the core-antigen vaccine for coliform mastitis . All of the commercially available vaccines for this indication are bacterins of rough mutants of E . coli strain J5 or Salmonella spp . Preliminary success with an experimental vaccine based on the plasminogen activator of S . uberis is a very different approach for a mastitis vaccine . Little success has been reported with vaccination against other mastitis pathogens . For diagnostic methods, the high somatic cell count, as measured by direct count or indirect assays, remains the cornerstone of mastitis diagnosis . However, for subclinical mastitis, bacterial cell culture is a reliable diagnostic method . Pathogen identification may rely on older biochemical testing methods or newer commercial identification systems, depending on the laboratory budget . ELISA assays also have been used to assess herd infection status . Epidemiologic studies have used DNA fingerprinting and ribotyping, but none of these methods has yet produced an easily utilized commercial format . Within the next decade, additional efficacious vaccines for several of the most common agents for bovine mastitis are likely . A review written at that time then can be more fact than fiction.

J Clin Ultrasound, 1999 Jan, 27(1), 45 - 8
Aortic valve endocarditis caused by Salmonella species; Pliakos C et al.; We report a case of aortic valve endocarditis caused by an uncommon pathogen, Salmonella species . Transthoracic echocardiography proved to be inadequate to show the valvular destruction . Transesophageal echocardiography was instrumental in establishing the diagnosis of endocarditis by documenting aortic vegetations with attendant tissue damage extending beyond the valve leaflets (i.e., subvalvular and perivalvular damage) . The findings were anatomically confirmed at surgery, which also revealed an aortic root-right ventricular fistula and several aortic ring abscesses . Early implementation of transesophageal echocardiography is strongly recommended in patients with suspected endocarditis.

Enferm Infecc Microbiol Clin, 1998 Nov, 16(9), 408 - 12
{Epidemic outbreaks of salmonellosis caused by eating eggs}; Arnedo A et al.; BACKGROUND: Investigation of outbreaks of foodborne infections (OFI) by Salmonella associated with the consumption of hens' eggs from a same classification center of Castellon, and determination of origin, extension and to take measures of control and prevention . METHODS: Descriptive and case-control studies, microbiologic analysis of feces, suspicious foods, and eggs . Sampling of eggs in the classification center for estimation the prevalence of Salmonlla . RESULTS: In 1992, 5 OFI were detected, 4 collective (1 school, 2 restaurants, and 1 residence) and 1 at home, by the consumption of food prepared with eggs: fried or boiled eggs, omelette, souffle, 2 times, and home-made russian salad . Five hundred and forty-five persons were exposed and 364 were studied, with 100 case patients and 16 hospitalized . The range of attack rates was 10.5-87.0% . Samonella enteritidis (3 OFI) and S . typhimurium (3 OFI) were the infectious agents . In February 1993, the prevalence of Salmonella in eggs from the center was 0.26% (4/1.524) (S . enteritidis, 2 isolates, and S . typhimurium, 2 isolate), three on the shell, and one in the yolk . Two farmhouses of the six supplied were infected . CONCLUSIONS: These outbreaks indicate that salmonellosis by egg's consumption are frequent here and investigation of infection sources is necessary.

Southeast Asian J Trop Med Public Health, 1998 Jun, 29(2), 416 - 24
Untreatable infections?--The challenge of the 21st century; Parry CM; The triumph of antibiotics over bacterial pathogens that has occurred in the latter half of this century looks increasingly threatened as we approach the new millennium . Increasing resistance in important pathogens such as Mycobacterium tuberculosis, Shigella, and Streptococcus pneumoniae threatens the lives of millions . The increasing problems with drug resistance in (C . diphtheriae, Salmonella typhi and the pneumococcus in Vietnam are presented as examples of the challenge confronting tropical countries.

Allergol Immunopathol (Madr), 1998 Sep-Oct, 26(5), 241 - 9
Chronic granulomatous disease: six new cases; Martin Mateos MA et al.; We report six new cases of chronic granulomatous disease (CGD) diagnosed at our service . The cases represent 1.1% of all primary immunodeficiencies diagnosed . Four of the children were boys and two were girls . The hereditary mechanism was X-linked in three cases and autosomal recessive in the other three . Clinical manifestations appeared before the age of 2 years in all cases; the illness appeared earlier in males, and was more severe, consisting of bacterial infections such as abscesses in the liver, lungs or skin, suppurating lymphadenitis and mastoiditis . None of the patients had osteomyelitis . The germs isolated were bacteria (Staphylococcus, Salmonella, Serratia, Pseudomonas, Enterococcus) and fungi (Candida, Aspergillus, Trichopyton) . Orientative complementary evidence was intense leukocytosis, high levels of acute phase reactants (PCR and VSG), polyclonal hypergammaglobulinemia and high LB ant LT4 levels . Definitive diagnosis was provided by the NBT test and chemiluminescence in all cases.

Wien Klin Wochenschr, 1998 Nov 27, 110(22), 802 - 3
Supraclavicular abscess caused by Salmonella enteritidis in patient without gastrointestinal symptoms; Vajo Z et al.; Soft tissue infections are among the rare manifestations of extra intestinal salmonellosis and occur more frequently in immunocompromised patients . Herein we report a case of a 51-year-old white male with type II . diabetes mellitus, diagnosed with supraclavicular abscess caused by Salmonella enteritidis . The patient denied any gastrointestinal symptoms, and stool cultures were negative . After incision, drainage, and administration of intravenous ampicillin (4 x 1.5 g/day for two weeks) the patient recovered completely . To our knowledge, this is the first reported case of cervical soft tissue abscess caused by Salmonella enteritidis without preceding gastrointestinal symptoms . We feel that the presence of diabetes was a risk factor for developing the infection.

Diagn Microbiol Infect Dis, 1998 Nov, 32(3), 147 - 57
Application of recombinant fimbrial protein for the specific detection of Salmonella enteritidis infection in poultry; Rajashekara G et al.; A number of disease outbreaks of Salmonella enterica serotype enteritidis (SE) in humans have been traced to the consumption of SE-contaminated egg and egg products . A rapid, specific, and inexpensive method of detecting SE infection in poultry is necessary to reduce human outbreaks . We evaluated rSEF14 fimbrial antigen of SE for specific detection of SE-infected birds in latex agglutination test and enzyme-linked immunosorbent assay . rSEF14 antigen was highly specific in identifying birds infected with SE . The sera from birds infected with closely related serogroup-D Salmonella and other avian pathogens did not react with rSEF14 antigen . The rSEF14 antigen identified antibodies in serum of 88% of birds during the first 2 weeks of infection, and 100% of the birds subsequently . The SE-specific antibodies were detected in egg yolk as early as 6 days post-infection in rSEF14-enzyme-linked immunosorbent assay . Our results suggest that rSEF14-based assays could be used as screening tests for detection of SE antibodies and would overcome the cross reactions observed with existing serological tests.

J Bacteriol, 1999 Jan, 181(2), 556 - 62
The ompB operon partially determines differential expression of OmpC in Salmonella typhi and Escherichia coli; Martinez-Flores I et al.; Expression of the Escherichia coli OmpC and OmpF outer membrane proteins is regulated by the osmolarity of the culture media . In contrast, expression of OmpC in Salmonella typhi is not influenced by osmolarity, while OmpF is regulated as in E . coli . To better understand the lack of osmoregulation of OmpC expression in S . typhi, we compared the expression of the ompC gene in S . typhi and E . coli, using ompC-lacZ fusions and outer membrane protein (OMP) electrophoretic profiles . S . typhi ompC expression levels in S . typhi were similar at low and high osmolarity along the growth curve, whereas osmoregulation of E . coli ompC in E . coli was observed during the exponential phase . Both genes were highly expressed at high and low osmolarity when present in S . typhi, while expression of both was regulated by osmolarity in E . coli . Complementation experiments with either the S . typhi or E . coli ompB operon in an S . typhi DeltaompB strain carrying the ompC-lacZ fusions showed that both S . typhi and E . coli ompC were not regulated by osmolarity when they were under the control of S . typhi ompB . Interestingly, in the same strain, both genes were osmoregulated under E . coli ompB . Surprisingly, in E . coli DeltaompB, they were both osmoregulated under S . typhi or E . coli ompB . Thus, the lack of osmoregulation of OmpC expression in S . typhi is determined in part by the ompB operon, as well as by other unknown trans-acting elements present in S . typhi.

Environ Mol Mutagen, 1998, 32(4), 377 - 86
Gamma-glutamyl transpeptidase-dependent mutagenicity and cytotoxicity of gamma-glutamyl derivatives: a model for biochemical targeting of chemotherapeutic agents; Keren R et al.; Many carcinomas in humans are rich in gamma-glutamyl transpeptidase (GGT), a plasma membrane enzyme that reacts with extracellular substrates . Thus, biochemical targeting of chemotherapeutic agents may be achieved by converting anticancer drugs into their gamma-glutamyl derivatives . Chemical conversion of phenylhydrazine (PH) and biochemical modification of daunomycin (DM) into their gamma-glutamyl derivatives gamma-glutamyl phenylhydrazine (GGPH) and gamma-glutamyl DM (GGDM) resulted in the abolishment of their mutagenicity and cytotoxicity, as judged by decreased viability and increased mutant yields in cultures of several Salmonella Ames strains . Commercial gamma-glutamyl-p-nitroanilide (GGPNA) was not toxic or mutagenic . Mutagenicity and/or cytotoxicity of these gamma-glutamyl derivatives were restored upon reaction with GGT, with concomitant release of PH, and p-nitroaniline (PNA) . The GGT-dependent release of DM from GGDM was demonstrated by thin layer chromatography (TLC), spectral analysis, and specific mutagenicity . Mutagenicity and/or cytotoxicity of gamma-glutamyl derivatives increased in the presence of glycylglycine, a GGT activator, and decreased in the presence of serine-borate, a GGT inhibitor . GGDM retained considerable DNA binding capacity . Its inability to kill and mutagenize was due to altered transport properties . The results are compatible with the notion that gamma-glutamylation is a feasible method for biochemical targeting of drugs containing a primary amino group to GGT-rich tumors.

Mamm Genome, 1998 Dec, 9(12), 1027 - 31
cDNA cloning, structural organization, and expression of the sheep NRAMP1 gene; Bussmann V et al.; Mouse resistance to several intracellular pathogens including Mycobacteria, Leishmania, and Salmonella is under the control of the Chromosome (Chr) 1 Natural Resistance Associated Macrophage Protein I gene (Nramp1) . This gene could have an economic and health importance for domestic animals and humans as well . Therefore, equivalents of the NRAMP1 gene have been cloned by several research groups in various animal species . To study in sheep the influence of the NRAMP1 gene on the susceptibility to intracellular pathogens induced diseases, we have cloned the sheep NRAMP1 cDNA by screening a splenic cDNA library . The genomic organization of the sheep NRAMP1 gene was then determined by sequencing the exon/intron boundaries . The transcription start points (tsp) from the NRAMP1 mRNA have been located with primer extension experiments . RT-PCR reactions have been used to determine the profile of mRNA expression of this gene.

Microb Pathog, 1998 Nov, 25(5), 267 - 77
Nitric oxide mediates immunosuppression induced by Listeria monocytogenes infection: quantitative studies; MacFarlane AS et al.; Our laboratory has shown that immunization of mice with an attenuated strain of Salmonella typhimuriuminduces profound suppression in the capacity of splenocytes to mount an in vitro antibody plaque-forming cell (PFC) response to sheep red blood cells (SRBC) and to proliferate in response to mitogens . In vitro addition of NG-monomethyl-L-arginine (NMMA), an inhibitor of nitric oxide (NO) synthase, to cell cultures from Salmonella-immunized mice completely blocked suppression of the PFC responses, implicating that NO is the suppressor factor . The present study quantified the role of nitric oxide in immunosuppression induced by Listeria monocytogenes, a gram positive intracellular pathogen of macrophages . Listeria infection resulted in suppression of the PFC assay at inoculating doses of greater than 6.5x10(3)colony forming units, with no suppression observed at lower doses . Suppression correlated with increased nitrite production . Addition of NMMA to spleen cell cultures taken from Listeria-infected mice completely blocked suppression of the PFC response, and returned nitrite production to baseline levels . In regard to Listeria-induced suppression of responses to the mitogen, Concanavalin A (Con A), the parameters were different from those observed for the PFC response . There was a direct correlation between the log10of the inoculating dose of Listeria and degree of immunosuppression, with suppression observed at doses as low as 1x10(3)cells . Addition of NMMA to the Con A-stimulated cultures resulted in reduced nitrite levels, but only partial restoration of the proliferative responses . Co-culture of splenocytes from Listeria inoculated mice with normal splenocytes in media with NMMA and reduced levels of L-arginine resulted in complete reversal of suppressed responses to Con A . Similar differences in ease of reversing suppression of the PFC response, as compared with responses to Con A, were previously noted using cells taken from Salmonella-infected mice . The present results show that a gram positive intracellular pathogen of macrophages, L . monocytogenes, induces immunosuppression in mouse spleen cells by a nitric oxide mediated mechanism that closely parallels that induced by the gram negative pathogen, S . typhimurium .

J Med Microbiol, 1998 Jun, 47(6), 489 - 97
SERE, a widely dispersed bacterial repetitive DNA element; Rajashekara G et al.; The presence of a Salmonella serotype Enteritidis repeat element (SERE) located within the upstream regulatory region of the sefABCD operon encoding fimbrial proteins is reported . DNA dot-blot hybridisation analyses and computerised searches of genetic databases indicate that SERE is well conserved and widely distributed throughout the bacterial and archaeal kingdoms . A SERE-based polymerase chain reaction (SERE-PCR) assay was developed to fingerprint 54 isolates of Enteritidis representing nine distinct phage types and 54 isolates of other Salmonella serotypes . SERE-PCR identified five distinct fingerprint profiles among the 54 Enteritidis isolates; no correlation between phage types and SERE-PCR fingerprint patterns was noticed . SERE-PCR was reproducible, rapid and easy to perform . The results of this investigation suggest that the limited heterogeneity of SERE-PCR fingerprint patterns can be utilised to develop serotype- and serogroup-specific fingerprint patterns for isolates of Enteritidis.

J Med Microbiol, 1998 May, 47(5), 427 - 34
Evaluation of PCR-based methods and ribotyping performed with a mixture of PstI and SphI to differentiate strains of Salmonella serotype Enteritidis; Landeras E et al.; The capacity to differentiate Salmonella serotype Enteritidis strains by PCR ribotyping; RAPD typing with three arbitrary primers and ribotyping with a mixture of PstI and SphI or 'PS ribotyping', was evaluated on a series of 65 strains associated with human infections and 11 reference strains . The series had been analysed previously by phage typing and ribotyping performed with PstI and SphI, separately . All methods typed all the strains; however, only ribotyping showed good reproducibility and sensitivity . Twenty-two PS ribotypes (discrimination index = 0.74) were identified, differentiating strains ascribed to seven phage types (PTs 1, 4, 6, 6a, 7, 8 and RDNC) as well as phage untyped strains . Conversely, some strains of PTs, 1, 4, 5a, 6, 6a, 7, 34 and RDNC showed the most frequent PS ribotype . By PCR ribotyping a single profile was found; while by RAPD typing, one, two or three RAPD types were identified with the primers MK22, OPB6 and OPB17, respectively . All Spanish strains were assigned to a single combined RAPD type, except PT11 strains which showed a different and specific RAPD type with OPB17 . The banding patterns defining the PS ribotypes were interpreted more easily and the patterns could be compared more accurately than the banding patterns defining RAPD types . A similarity dendrogram generated from the 22 PS ribotypes was traced and compared with RAPD types and phage types . Data from this work indicated that 'PS ribotyping' was the most useful genetic procedure to differentiate Enteritidis strains, and, therefore, it can be used as a complementary or alternative typing method to phage typing within this serotype.

J Med Microbiol, 1998 May, 47(5), 383 - 9
Impact of medium-chain monoglycerides on intestinal colonisation by Vibrio cholerae or enterotoxigenic Escherichia coli; Petschow BW et al.; Although a number of studies have shown that various free fatty acids (FFAs) and monoacylglycerides (MGs) have bactericidal properties in vitro, the role of these compounds in vivo has not been determined . This study evaluated the antibacterial properties of medium-chain MGs and FFAs for different bacterial enteropathogens with an in-vitro bacterial killing assay and an in-vivo model of intestinal colonisation . Incubation of test bacteria with medium-chain MGs for 4 h led to 100-10,000-fold reductions in numbers of viable cells of Vibrio cholerae, Salmonella typhi, Shigella sonnei and enterotoxigenic Escherichia coli (ETEC) . Lauric acid was the only medium-chain FFA to show comparable in-vitro bactericidal activity . The ability of dietary MGs to reduce or eliminate bacterial colonisation of the intestinal tract was evaluated in mice that were predisposed to bacterial colonisation by treatment with streptomycin (STR+) . Mice were treated with streptomycin, challenged intragastrically with V . cholerae or ETEC, and given monocaprin (C10:0 MG) either concurrently or as part of the daily diet . Control mice given STR+ without MGs and challenged with V . cholerae or ETEC showed high numbers of challenged bacteria in gastrointestinal contents by 1 h after administration . Concurrent administration of V . cholerae and C10:0 MG (2.5 mg/ml) caused > 1000-fold reduction in numbers of V . cholerae recovered from the gastrointestinal tracts of STR+ mice . Concurrent administration of C10:0 MG with ETEC did not cause a reduction in the number of viable ETEC present in the intestinal tract of STR+ mice . Administration of C10:0 MG in the diet had no effect on the number of viable V . cholerae or ETEC associated with caecal or ileal tissue of STR+ mice when C10:0 MG in the diet was started 1 day before, the same day, or 2 days after bacterial challenge . Collectively, these results suggested that dietary MGs may prevent intestinal colonisation by bacterial enteropathogens if administered at the time of exposure, but have little effect on established intestinal infections.

Mutat Res, 1999 Jan, 436(1), 113 - 22
Statistical methods for the Ames Salmonella assay: a review; Kim BS et al.; The Ames Salmonella assay remains the most widely used in vitro genotoxicity assay . Several statistical methods have been proposed for its analysis {B.H . Margolin, N . Kaplan, E . Zeiger, Statistical analysis of the Ames Salmonella/microsome test, Proc . Natl . Acad . Sci., 78 (1981) 3779-3783; L.E . Myers, N.H . Saxton, L.I . Southerland, T.J . Wolff, Regression analysis of Ames test data, Environ . Mol . Mutagen., 3 (1981) 575-586; A.G . Stead, V . Hasselblad, J.P . Creason, L . Claxton, Modelling the Ames test, Mutation Res., 85 (1981) 13-27; L . Bernstein, J . Kaldor, J . McCaan, M.C . Pike, An empirical approach to the statistical analysis of mutagenesis data from the Salmonella test, Mutation Res., 97 (1982) 267-281; N.E . Breslow, Extra-Poisson variation in log-linear models, Appl . Stat., 33 (1984) 38-44; J . Wahrendorf, G.A.T . Mahon, M . Schumacher, A nonparametric approach to the statistical analysis of mutagenicity data, Mutation Res., 147 (1985) 5-13; D.G . Simpson, B.H . Margolin, Recursive nonparametric testing for dose-response relationships subject to downturns at high doses, Biometrika, 73 (1986) 589-596; D.G . Simpson, B.H . Margolin, Nonparametric testing for dose-response curves subject to downturns: Asymptotic power considerations, Annals Stat., 18 (1990) 373-390.} . In this paper we review recent literature to see what statistical methods are in fact employed for the analysis of the Ames assay . We then note that these methods can be classified into a common category in the framework of Haynes and Eckardt's mutation induction kinetics model {R.H . Haynes, F . Eckardt, Mathematical analysis of mutation induction kinetics, in: F.J . de Serres, A . Hollaender (Eds . ), Chemical Mutagens, Principles and Methods for Their Detection, Vol . 6, Plenum, New York, 1980, pp . 271-307} . The value in knowing this is that most methods of analysis considered here will likely exhibit common statistical behavior . These analyses are computationally intensive, e.g., {B.H . Margolin, N . Kaplan, E . Zeiger, Statistical analysis of the Ames Salmonella/microsome test, Proc . Nat . Acad . Sci., 78 (1981) 3779-3783}, hence the ready availability of computer programs is essential if biologists are to use these methods . We briefly review two statistical software programs that are available in the public domain, and describe in detail a third program, Salm, {B.H . Margolin, N . Kaplan, E . Zeiger, Statistical analysis of the Ames Salmonella/microsome test, Proc . Nat . Acad . Sci., 78 (1981) 3779-3783; B.H . Margolin, B.S . Kim, K . Risko, The Ames Salmonella/microsome assay: Issues of inference and validation, J . Amer . Stat . Assoc., 84 (1989) 651-661} . The Salm program is obtainable through the file transfer protocol (ftp) or using a WWW browser . Finally, we discuss two statistical consequences of naively applying the two-fold rule, a method of analysis employed by a number of researchers .

Avian Dis, 1998 Oct-Dec, 42(4), 818 - 23
Simultaneous occurrence of Salmonella arizonae in a sulfur crested cockatoo (Cacatua galerita galerita) and iguanas; Oros J et al.; A case of fatal hepatitis in a captive sulfur crested cockatoo (Cacatua galerita galerita) in which Salmonella arizonae was microbiologically and immunohistochemically detected is described . The death of the cockatoo was closely related to the arrival of a group of 10 green iguanas (Iguana iguana) at a pet shop, and no previous clinical signs were observed in the cockatoo . The most important lesion observed at necropsy of the cockatoo was a multifocal necrotic hepatitis . Salmonella arizonae was isolated from the liver of the cockatoo and was detected immunohistochemically mainly around the edges of necrotic foci . Four iguanas died 3 days later showing a severe enteritis, and Salmonella arizonae was isolated from these lesions . The importance of quarantine and, because of pathogens such as Salmonella, the need to house reptiles at a distance from avian species, mainly psittacids, are reinforced . This is the first report of Salmonella arizonae infection in a cockatoo.

Avian Dis, 1998 Oct-Dec, 42(4), 807 - 11
Application of flagella-based immunoassays for serologic detection of Salmonella pullorum infection in chickens; Gast RK et al.; Occasional Salmonella pullorum outbreaks still occur in commercial poultry flocks despite widespread serologic testing, raising concerns about the efficacy of standard agglutination-based serologic assays for detecting infections with current field strains . The recent observation that many S . pullorum strains are recognized by antibodies to certain Salmonella flagellar proteins suggests that similar antibodies might be elicited in infected birds . In the present study, flagella-based enzyme immunoassays were developed and applied to detect antibodies in hens experimentally infected with recent S . pullorum isolates . Antibodies were detected in 29%-44% of serum samples from orally inoculated hens by two flagella-based immunoassays . Similar frequencies of positive results (33%-41%) were obtained by applying two standard agglutination-based tests for antibodies to S . pullorum . Antibodies to flagellar antigens, if also present in naturally infected chickens, could provide an alternative method for detecting S . pullorum infection in poultry flocks.

Avian Dis, 1998 Oct-Dec, 42(4), 690 - 7
Antimicrobial resistance and minimum inhibitory concentrations of bacteria isolated from bustards in the United Arab Emirates; Bailey TA et al.; The resistance to 11 antimicrobial agents of bacteria isolated from clinical and postmortem cases of five species of bustards maintained in captivity in the United Arab Emirates (UAE) from 1995 to 1997 was determined by disc sensitivity . Of 226 isolates, 169 (74.8%) were gram-negative bacilli, with the majority identified as Escherichia coli (28.8%) and Pseudomonas aeruginosa (19%) . The isolates of E . coli showed a high prevalence of resistance to amoxycillin (69%), tetracycline (66.7%), and sulphamethoxazole (43.3%) . Moderate resistance to enrofloxacin was observed in E . coli (30%) and P . aeruginosa (19%) isolates . The minimum inhibitory concentrations (MICs) to seven antimicrobial agents were determined for 133 bacterial isolates from bustards during 1996 to 1997 . Enrofloxacin (concentration required to inhibit 50% of the isolates {MIC50} < 0.5 microgram/ml) and gentamicin (MIC50 < or = 1.0 microgram/ml) exhibited good activity against both gram-negative bacilli and staphylococci isolated from bustards . Enrofloxacin (MIC50 < or = 1.5 micrograms/ml), gentamicin (MIC50 < or = 2.0 micrograms/ml), and piperacillin (MIC50 < or = 4.0 micrograms/ml) exhibited good activity against P . aeruginosa isolates . Amoxycillin/clavulanic acid showed good activity (concentration required to inhibit 90% of the isolates {MIC90} < or = 2.0 micrograms/ml) against gram-positive cocci and moderate activity (MIC50 < or = 3.0 micrograms/ml) against E . coli, Salmonella spp., and Klebsiella spp . Amoxycillin exhibited good activity (MIC50 < or = 0.5 microgram/ml) against gram-positive organisms and moderate activity (MIC50 < or = 1.0 microgram/ml) against Salmonella spp . These results provide information on the prevalence of resistant bacterial strains and the MICs of organisms derived from bustards in the UAE.

Avian Dis, 1998 Oct-Dec, 42(4), 651 - 6
Effect of a commercial competitive exclusion culture (Preempt) on mortality and horizontal transmission of Salmonella gallinarum in broiler chickens; Nisbet DJ et al.; A commercial competitive exclusion (CE) culture (PREEMPT) was evaluated for its ability to decrease mortality during the first 10-12 days posthatch resulting from the causative agent of fowl typhoid, Salmonella gallinarum . In the first experiment, chicks provided the CE culture on day of hatch and challenged with 10(5) S . gallinarum on day 3 had a significant decrease in mortality compared with non-CE-treated S . gallinarum-challenged chicks in all four replicates . Mortality for control chicks when averaged across all four replicates was 74% compared with 7.5% for the CE-treated chicks . A second experiment was performed that was designed to measure the efficacy of the CE culture in decreasing the horizontal transmission of this pathogen from infected to uninfected chicks when commingled . Day-of-hatch chicks that were directly infected (seeders) with 10(5) S . gallinarum and provided no CE culture averaged 86% S . gallinarum organ positive and 80% mortality during the first 12 days posthatch across four replicates . Untreated contact (not directly infected) chicks that were commingled with the seeder chicks averaged 84% S . gallinarum organ positive and 54% mortality, and the commingled CE-treated contact chicks (provided CE culture on day of hatch) average 35% S . gallinarum organ positive and 9% mortality during the same time period . These results are of importance to the poultry industry in geographic areas where poultry production is adversely affected by fowl typhoid and indicate that treating newly hatched chicks with this commercial CE culture may be a novel way of decreasing economic losses associated with this highly pathogenic organism.

Rev Inst Med Trop Sao Paulo, 1998 Jul-Aug, 40(4), 233 - 5
Salmonella-S . mansoni association in patients with acquired immunodeficiency syndrome; Lambertucci JR et al.; Two young men with Salmonella bacteraemia, active schistosomiasis and the acquired immunodeficiency syndrome are reported . The clinical presentation comprised nonspecific signs and symptoms, such as fatigue, malaise, weight loss, diarrhoea, prolonged fever, and hepatosplenomegaly . In one patient, liver biopsy showed poorly formed granulomata around Schistosoma mansoni eggs and hepatitis . Treatment of schistosomiasis alone induced consistent clinical improvement with eventual cure of both Salmonella and S . mansoni infections . Recognition of the Salmonella-S . mansoni association in patients with AIDS is important because treatment of schistosomiasis makes a difference, improving the prognosis of this otherwise, recurrent, potentially fatal bacteraemia.

Haemophilia, 1998 Sep, 4(5), 752 - 4
An unusual haemarthrosis in an HIV-seronegative haemophilia A patient; Menart C et al.; We report the case of a severe haemophilia A patient with an anti-factor VIII antibody who presented with a thigh haematoma and 1 year later with an elbow haemarthrosis infected by Salmonella enteritidis . These two infections were treated by antibiotics . The probable origin of these infections seems to be an anal fistula . The occurrence of a septic arthritis due to Salmonella is rare, and to our knowledge has never been reported in HIV-negative haemophilic patients . The differential diagnosis of haemarthrosis and septic arthritis in a haemophilic patient is also discussed.

Am J Respir Crit Care Med, 1999 Jan, 159(1), 252 - 7
Role of nitric oxide in sepsis-associated pulmonary edema; Hinder F et al.; Transient pulmonary hypertension after inhibition of nitric oxide synthase (NOS) does not alter pulmonary reflection coefficients or lymph flows in endotoxemic sheep . To test the effects of persistent pulmonary hypertension induced by N omega-nitro-L-arginine methylester (L-NAME) and of inhaled NO on pulmonary edema, 18 sheep (three groups) were chronically instrumented with pulmonary artery catheters, femoral arterial fiberoptic thermistor catheters, and tracheostomy . The awake, spontaneously breathing animals received Salmonella typhi endotoxin (lipopolysaccharide; LPS) (10 ng/kg/ min) for 28 h . After 24 h, an airflow of 6 L/min was delivered through the tracheostomy . One group of animals (L-NAME/air) received L-NAME intravenously (25 mg/kg + 5 mg/kg/h) and breathed air . The second group (L-NAME/NO) was given L-NAME and NO (40 ppm) was added to the airflow . The third group was given NaCl 0.9% and breathed air (NaCl/air) . Extravascular lung water was measured through the double-indicator dilution technique . Endotoxemia caused pulmonary edema, which was aggravated by L-NAME . Breathing of NO normalized pulmonary artery pressure (Ppa) and ameliorated pulmonary edema . Inhalation of NO may therefore be a therapeutic option for pulmonary edema associated with pulmonary hypertension.

Appl Environ Microbiol, 1999 Jan, 65(1), 297 - 300
Bacterial resistance to ultrasonic waves under pressure at nonlethal (manosonication) and lethal (manothermosonication) temperatures; Pagan R et al.; The decimal reduction times of Streptococcus faecium, Listeria monocytogenes, Salmonella enteritidis, and Aeromonas hydrophila corresponding to heat treatment at 62 degrees C were 7.1, 0.34, 0.024, and 0.0096 min, and those corresponding to manosonication treatment (40 degrees C, 200 kPa, 117 microm) were 4.0, 1.5, 0.86, and 0.90 min, respectively . The manosonication decimal reduction times of the four species investigated decreased sixfold when the amplitude was increased from 62 to 150 microm and fivefold when the relative pressure was raised from 0 to 400 kPa . In L . monocytogenes, S . enteritidis, and A . hydrophila, the lethal effect of manothermosonication was the result of the addition of the lethal effects of heat and manosonication, whereas in S . faecium it was a synergistic effect.

Poult Sci, 1998 Dec, 77(12), 1846 - 51
B-complex associated immunity to Salmonella enteritidis challenge in congenic chickens; Cotter PF et al.; Six trials were conducted during which a total of 12 congenic lines (University of California-Davis, UCD) homozygous for various B-complex haplotypes, were challenged as neonates by intraperitoneal injection with either of two isolates of Salmonella enteritidis . Because these B haplotypes were expressed on a common genetic background (highly inbred Line UCD 003), and mortality differences among lines were statistically significant in three of the six trials, and morbidity (body weight) differences were significant in another trial; it is suggested that B-complex alleles affect the degree of immunity to these isolates . When all lines and trials were compared, line 342 (BC/BC) emerged as particularly resistant, whereas lines 253 (B18/B18) and 254 (B15/B15) were more susceptible . The remainder of the lines were of neutral (intermediate) susceptibility . Sex did not appear to influence the results of the challenge, but more resistance was observed with an increase in the age at inoculation . Although the mechanism that determined this resistance is unknown it was present as early as 3 d of age, and it is suggested that complement proteins, which have a known role in protection from bacterial infections, and are encoded by genes located within the B-complex, or acute phase proteins, may account for these observations . The results provide additional evidence for the importance of the B-complex in determining immunity to Salmonella.

Poult Sci, 1998 Dec, 77(12), 1759 - 62
Persistence of Salmonella enteritidis from one day of age until maturity in experimentally infected layer chickens; Gast RK et al.; In each of two replicate trials, 1-d-old chicks were inoculated orally with a phage type 13 Salmonella enteritidis isolate (resistant to nalidixic acid) . Although S . enteritidis was found in the livers, spleens, and ceca of all sampled chicks at 1 wk postinoculation, colonization generally persisted beyond 4 wk postinoculation only in the ceca . Nearly half of the remaining hens were still shedding S . enteritidis in their feces at 24 wk of age, but only 1 of 62 hens laid eggs that were internally contaminated with S . enteritidis during the initial 4 to 6 wk of egg production . Chickens exposed to S . enteritidis shortly after hatching can apparently remain infected until maturity, at which time they might produce contaminated eggs or spread the infection to other susceptible, previously unexposed hens.

Pathol Biol (Paris), 1998 Oct, 46(8), 613 - 6
{Evaluation of the Widal test for diagnosing typhoid fever in Lebanon}; Hamze M et al.; Typhoid fever is a major public health problem in developing countries . In Lebanon, where the sanitary infrastructure was severely damaged during the civil war, the high prevalence of typhoid fever creates a pressing need for a rapid and reliable diagnostic tool . To evaluate the diagnostic usefulness of the Widal test, patients with a positive blood culture for Salmonella typhi (n = 78) were compared to controls with fever due to another infection (n = 65) and with blood donors (n = 96) . Discrimination between the patient group and the two control groups was best when an agglutinin O titer of 1/160 or more was used . With this cutoff, sensitivity was 67.9%; specificity was 93.8% versus the febrile controls and 100% versus the blood donors . These results suggest that despite its well-known limitations the Widal test remains a valuable tool for typhoid fever control in many developing countries.

Lett Appl Microbiol, 1998 Dec, 27(6), 379 - 82
Isolation of Salmonella resistant to hypochlorous acid from a poultry abattoir; Mokgatla RM et al.; Salmonella is a Gram-negative bacterium that has been implicated in several food-borne poisoning outbreaks . Poultry products are considered to be the major vehicles of food-borne poisoning caused by Salmonella . The resistance of Salmonella, isolated from different stages in a local poultry abattoir, to hypochlorous acid (HOCl) was studied . Isolates cultured in quarter strength Tryptone Soya Broth were treated with 72 ppm HOCl, incubated at 30 degrees C with shaking, and absorbance was measured at 660 nm every 20 min . A number of resistant isolates, which carried on growing following HOCl addition, were obtained . All the isolates from the bleeding stage were sensitive to HOCl, whereas those from the scalding stage were resistant to HOCl . Other stages had a population of resistant and sensitive isolates . It is evident that some Salmonella will grow in the presence of concentrations of HOCl deemed to be inhibitory . Hence, an effective concentration of HOCl must be applied in poultry abattoirs to ensure that all the Salmonella are eradicated.

J Appl Microbiol, 1998 Dec, 85(6), 933 - 40
Comparison of ribotyping and arbitrarily primed PCR for molecular typing of Salmonella enterica and relationships between strains on the basis of these molecular markers; Hilton AC et al.; Arbitrarily primed PCR (AP-PCR) using a discriminatory 10-mer primer and an automated EcoRI ribotyping technique (Riboprinter) were compared for their ability to discriminate between 100 serovars of Salmonella, including multiple isolates representing Salm . Enteritidis PT4 and Salm . Typhimurium DT104 . Profiles generated by each method were subjected to numerical analysis using GelCompar software, resulting in the construction of phylogenetic trees and calculation of Simpson's numerical index of diversity (DI) . Both methods were highly discriminatory for isolates of Salmonella (Ribotype DI = 0.990, AP-PCR DI = 0.997) with EcoRI ribotyping proving more discriminatory than AP-PCR for isolates of Typhimurium DT104 . The population structure was found to be clonal by numerical analysis of markers generated by both methods with serovars being polyphyletic in some cases and grouped in a single cluster in others . No absolute correlation was observed in the relationships between strains formed on the basis of ribo- and AP-PCR markers and serological characteristics.

J Gastroenterol Hepatol, 1998 Nov, 13(11), 1119 - 24
Inflammatory bowel disease in Saudi Arabia: presentation and initial management; Isbister WH et al.; Non-specific Inflammatory Bowel disease (IBD) is infrequently seen in the Arabs of the Arabian Peninsula . This paper documents the presentation and initial management of 101 such Arabs treated for inflammatory bowel disease between 1976 and 1994 . Medical records were examined and patients were classified according to the Organisation Mondiale de Gastroenterologie diagnostic scoring system . Sixty-seven patients had mucosal ulcerative colitis, 28 Crohn's disease (CD) and six indeterminate colitis; age range 2-71 years . Three patients had a family history of (IBD) . The diagnosis was made by a combination of the patients' history, physical, radiological, endoscopic and histological examination; however, eight patients were not examined endoscopically and one in four patients was not biopsied at presentation . Thirty-nine patients did not receive any treatment prior to referral . One in three patients was first treated as inpatients . Giardia, Amoeba, Salmonella, Shigella or Schistosoma were detected in the stools of 36 patients at presentation . Following appropriate treatment, these infections were eliminated but the patients' symptoms persisted . Six patients who were thought to have gastrointestinal tuberculosis were subsequently diagnosed with CD . Ten patients had extraintestinal manifestations of their IBD and 11 had side effects (osteoporosis, Cushingoid features and growth retardation) from steroid treatment at other hospitals . Diagnosis was often delayed because infectious diarrhoea was common and awareness was low . Patients were referred late and some had developed complications of therapy.

J Hosp Infect, 1998 Dec, 40(4), 295 - 302
An outbreak of extended-spectrum, beta-lactamase-producing Salmonella senftenberg in a burns ward; Revathi G et al.; A strain of Salmonella senftenberg resistant to ceftazidime, gentamicin, chloramphenicol and ciprofloxacin was isolated from burn wounds of eight patients on a burns ward of a hospital in Delhi, India . The organism, which had probably been spread from patient to patient on staff hands, produced the extended-spectrum beta-lactamase SHV-5 and the aminoglycoside-modifying enzymes AAC(3)II + AAC(6') . The strain was not isolated from stool cultures of any of the patients or staff, apart from the index patient who had a history of diarrhoea and fever before admission . The outbreak ended in three weeks, after the implementation of strict handwashing . This is the first report of SHV-5 beta-lactamase in Salmonella spp . and also the first report of SHV-5 in India . The extended-spectrum beta-lactamases that have been reported in Salmonella spp . now include the Group 2 be enzymes SHV-2, SHV-5, TEM-3, TEM-25, TEM-27, CTX-M2, PER-1 and PER-2, and the Group 1 enzymes DHA-1 and CMY-2 . The types of extended-spectrum beta-lactamases produced by salmonellas, their association with aminoglycoside resistance and their geographical distribution are now similar to those seen in klebsiella . Increasing antibiotic resistance in these organisms is reducing therapeutic options for the treatment of invasive disease.

Hunan Yi Ke Da Xue Xue Bao, 1997, 22(2), 165 - 6, 170
{Clinical and laboratory studies with typhoid fever 178 patients}; Lu M et al.; One hundred and seventy-eight cases of typhoid patients were studied on clinical and bacteriological aspects . The main clinical findings were as follows: (1) Most of the cases had sustained fever (66.3%) . (2) Gastroenterial symptoms developed as the disesase progressed . (3) Rose spots were found in 32.6% of them . (4) Liver and spleen were enlarged in 69.5% of the cases . (5) Blood eosinophil disappeared in most of the patients and leukopenia was noted in 94.3% . (6) There were toxic hepatitis (47.1%), toxic myocarditis (22.4%) and intestinal hemorrhage (19.7%) as complications . In the drug sensitivity test, the number of ampicillin-resistant and chloramphenicol-resistant strains of salmonella typhi was increased more than that seen 5 years ago (P < 0.05), however 100% of the strains were sensitive to amikacin, tobramycin, norflexacin, oflexacin and the third generation of the cephalosporin . For the time being, norflexacin and oflexacin were good and suitable drugs for the treatment of typhoid fever.

Emerg Infect Dis, 1998 Oct-Dec, 4(4), 667 - 9
Salmonella enteritidis PT6: another egg-associated salmonellosis?
Evans MR, Lane W, Ribeiro CD.
Salmonella Enteritidis phage type 6 (PT6) increased dramatically in the United Kingdom during 1997 . The sharp rise suggests that PT6 contamination has spread rapidly throughout a basic food commodity; however, the source and food vehicle remain unknown . We present evidence from three outbreaks suggesting a possible link between PT6 and eggs . Poor documentation of the egg supply network continues to pose problems for public health investigators . Thorough investigation of all future PT6 outbreaks and case-control studies of sporadic infections are needed to confirm the etiology of PT6 infection.

Mol Biol Evol, 1998 Dec, 15(12), 1685 - 95
Escherichia coli molecular phylogeny using the incongruence length difference test; Lecointre G et al.; Molecular phylogeny of the species Escherichia coli using the E . coli reference (ECOR) collection strains has been hampered by (1) the absence of rooting in the commonly used phenogram obtained from multilocus enzyme electrophoresis (MLEE) data and (2) the existence of recombination events between strains that scramble phylogenetic trees reconstructed from the nucleotide sequences of genes . We attempted to determine the phylogeny for E . coli based on the ECOR strain data by extracting from GenBank the nucleotide sequences of 11 chromosomal structural and 2 plasmid genes for which the Salmonella enterica homologous gene sequences were available . For each of the 13 DNA data sets studied, incongruence with a nonnucleotide whole-genome data set including MLEE, random amplified polymorphic DNA, and rrn restriction fragment length polymorphism data was measured using the incongruence length difference (ILD) test of Farris et al . As previously reported, the incongruence observed between the gnd and plasmid gene data and the whole-genome data was multiple, indicating numerous horizontal transfer and/or recombination events . In five cases, the incongruence detected by the ILD test was punctual, and the donor group was identified . Congruence was not rejected for the remaining data sets . The strains responsible for incongruences with the whole-genome data set were removed, leading to a "prior-agreement" approach, i.e., the determination of a phylogeny for E . coli based on several genes, excluding (1) the genes with multiple incongruences with the whole genome data, (2) the strains responsible for punctual incongruences, and (3) the genes incongruent with each other . The obtained phylogeny shows that the most basal group of E . coli strains is the B2 group rather than the A group, as generally thought . The D group then emerges as the sister group of the rest . Finally, the A and B1 groups are sister groups . Interestingly, the most primitive taxon within E . coli in terms of branching pattern, i.e., the B2 group, includes highly virulent extraintestinal strains with derived characters (extraintestinal virulence determinants) occurring on its own branch.

Immunol Lett, 1998 Nov, 64(1), 9 - 15
Effect of pre-existing carrier immunity on the efficacy of synthetic influenza vaccine; Ben-Yedidia T et al.; In our previous studies on the development of synthetic peptide-based vaccines, we have evaluated flagellin from a Salmonella typhi vaccine strain as a carrier molecule for synthetic peptides derived from the influenza virus . The results indicated that the use of recombinant flagella, expressing defined influenza epitopes, is adequate for induction of protection against a challenge infection . It is of importance to show that previous exposure to the carrier does not induce suppression of the response to such vaccine . In the present study we demonstrate that the protective effect is not impaired by pre-immunization with either the carrier flagellin molecule alone or with the intact salmonella . The immune response was manifested both by the level of antibodies produced and by a proliferative cellular response, as well as by an efficient protection of the mice from a sub-lethal challenge infection . Since prior exposure to the carrier did not result in immune suppression, we conclude that Salmonella flagellin is a suitable carrier for synthetic peptide based vaccines.

Infect Immun, 1999 Jan, 67(1), 201 - 5
Interaction of NK lysin, a peptide produced by cytolytic lymphocytes, with endotoxin; Andersson M et al.; NK lysin is a 9-kDa polypeptide that was originally isolated from porcine intestinal tissue based on its antibacterial activity . It is produced by cytolytic lymphocytes and is cytolytic against a number of different types of tumor cells . Here we report the binding of NK lysin to lipopolysaccharide (LPS) and its anti-LPS activity . NK lysin binds to matrix-coated LPS from Escherichia coli, Pseudomonas aeruginosa, and different strains of Salmonella enterica . Lipid A and polymyxin B inhibited the binding, demonstrating a preferential interaction of NK lysin with the lipid part of LPS . Chromium-labeled lymphoma cells were lysed by NK lysin, and LPS dose-dependently inhibited the cytolysis at equimolar amounts . In the same manner, NK lysin inhibited certain LPS-stimulated effects on mouse bone marrow cells as well as LPS binding to mouse granulocytes . These results suggest that NK lysin may be a another natural LPS-binding protein from lymphocytes that may participate in the endogenous defense response associated with elevated concentrations of LPS.

Food Chem Toxicol, 1998 Dec, 36(12), 1079 - 84
Shark cartilage-containing preparation: protection against reactive oxygen species; Felzenszwalb I et al.; There is overwhelming evidence to indicate that free radicals cause oxidative damage to lipids, proteins and nucleic acids and are involved in the pathogenesis of several degenerative diseases . Therefore, antioxidants, which can neutralize free radicals, may be of central importance in the prevention of these disease states . The protection that fruits and vegetables provide against disease has been attributed to the various antioxidants contained in them . Recently, an anti-inflammatory and analgesic activity of a water-soluble fraction from shark cartilage has been described . Using electrophoretical assays, bacteria survival and transformation and the Salmonella/mammalian-microsome assay, we investigated the putative role of shark cartilage-containing preparation in protecting cells against reactive oxygen species induced DNA damage and mutagenesis . If antimutagens are to have any impact on human disease, it is essential that they are specifically directed against the most common mutagens in daily life . Our data suggest that shark cartilage-containing preparation can play a scavenger role for reactive oxygen species and protects cells against inactivation and mutagenesis.

Mutagenesis, 1998 Nov, 13(6), 619 - 24
Comparative mutagenic and genotoxic effects of three antimalarial drugs, chloroquine, primaquine and amodiaquine; Chatterjee T et al.; Comparative mutagenic and genotoxic effects of three antimalarial drugs, chloroquine, primaquine and amodiaquine, were assessed in the Ames mutagenicity assay (in strains TA97a, TA100, TA102 and TA104) and in vivo sister chromatid exchange (SCE) and chromosome aberration (CA) assays in bone marrow cells of mice . These are the most commonly used antimalarial drugs available at present throughout the world . The results of the bacterial mutagenicity assays showed a very weak mutagenic effect of all three drugs in Salmonella strains TA97a and TA100 both with and without S9 mix and in TA104 only with S9 mix . The results of the in vivo SCE and CA assays indicate that these three drugs are genotoxic in bone marrow cells of mice.

Trans R Soc Trop Med Hyg, 1998 May-Jun, 92(3), 320 - 1
Serum thrombomodulin levels in patients with typhoid fever; Ohnishi K et al.; Elevated plasma or serum levels of thrombomodulin (TM) have been reported in some diseases . However, to our knowledge, plasma and serum levels of TM have not been investigated in febrile patients with typhoid fever . Serum TM and creatinine levels were determined in 7 male Japanese febrile patients with typhoid fever and 6 male Japanese healthy controls . The serum TM values of the patients and controls, in arbitrary units/mL, were 5.04 (SD = 1.69) and 2.93 (SD = 0.74), respectively (P < 0.025) . The serum creatinine levels of the patients and controls were 0.93 (SD = 0.16) mg/dL and 0.77 (SD = 0.10) mg/dL, respectively, and the lack of any significant difference between them suggests that delayed clearance from the kidneys was not the predominant explanation for the elevated serum TM levels . Although the numbers of patients and controls were small and more studies are needed, we conclude that elevated serum TM levels during the course of a febrile infection with Salmonella serovar typhi may reflect the disease activity.

Environ Health Perspect, 1998 Dec, 106 Suppl 6, 1435 - 40
Bioassay-directed fractionation and chemical identification of mutagens in bioremediated soils; Brooks LR et al.; Soil from a Superfund site (Reilly Tar Site, St . Louis Park, Minnesota) contaminated with polycyclic aromatic hydrocarbons (PAHs) from creosote was treated with several bioremediation technologies including bioslurry (BS), biopile (BP), compost (CMP), and land treatment (LT) . These treatment technologies are being evaluated in pilot scale laboratory systems by the U.S . Environmental Protection Agency's National Risk Management Research Laboratory in Cincinnati, Ohio . To evaluate the genotoxicity and identify the mutagens in the soil before and after the various treatments, fractionated extracts of five soils were bioassayed for mutagenic activity with a microsuspension modification of the Salmonella histidine reversion assay . Soils were extracted by sonication using dichloromethane (DCM) . The five extracts were fractionated in triplicate (two for bioassay and one for chemical analysis) by reverse-phase high-performance liquid chromatography (HPLC) using hexane/DCM/methanol, and the fraction for bioassay were solvent-exchanged into dimethyl sulfoxide by nitrogen evaporation . Forty HPLC fractions for each sample were bioassayed in strain YG1041 with and without exogenous liver metabolic activation . As shown in a companion paper, the mutagenicity of two treatments (BS and BP) was significantly greater than the mutagenicity of the untreated soil . Mutagenic fractions (> 500 revertants) were analyzed by gas chromatography/mass spectrometry (GC/MS) . PAH analysis of the soils indicated that all treatments were effective in reducing the total PAH concentration (48-74%) . Qualitative GC/MS analysis of the mutagenic fractions from the BS and BP treatments indicated that they contained azaarenes, which are mutagens . The CMP and LT processes were the most effective and least toxic bioremediation procedures based on mutagenic potency and chemical analysis . This research demonstrated that the combination of bioassays and chemical analysis provided a more accurate determination of toxicity in these complex environmental mixtures.

Environ Health Perspect, 1998 Dec, 106 Suppl 6, 1427 - 33
Genotoxicity of bioremediated soils from the Reilly Tar site, St . Louis Park, Minnesota; Hughes TJ et al.; An in vitro approach was used to measure the genotoxicity of creosote-contaminated soil before and after four bioremediation processes . The soil was taken from the Reilly Tar site, a closed Superfund site in Saint Louis Park, Minnesota . The creosote soil was bioremediated in bioslurry, biopile, compost, and land treatment, which were optimized for effective treatment . Mutagenicity profiles of dichloromethane extracts of the five soils were determined in the Spiral technique of the Salmonella assay with seven tester strains . Quantitative mutagenic responses in the plate incorporation technique were then determined in the most sensitive strains, YG1041 and YG1042 . Mutagenic potency (revertants per microgram extract) in YG1041 suggested that compost, land treatment, and untreated creosote soil extracts were moderately mutagenic with Arochlor-induced rat liver (S9) but were nonmutagenic without S9 . However, the bioslurry extract was strongly mutagenic and the biopile extract was moderately mutagenic either with or without S9 . A similar trend was obtained in strain YG1042 . The strong mutagenic activity in the bioslurry extract was reduced by 50% in TA98NR, which suggested the presence of mutagenic nitrohydrocarbons . Variation in reproducibility was 15% or less for the bioassay and extraction procedures . Bioavailability of mutagens in the biopile soil was determined with six solvents; water-soluble mutagens accounted for 40% of the total mutagenic activity and they were stable at room temperature . The mutagenic activity in the bioslurry and biopsile samples was due to either the processes themselves or to the added sludge/manure amendments . The in vitro approach was effective in monitoring bioremediated soils for genotoxicity and will be useful in future laboratory and in situ studies.

Vet Immunol Immunopathol, 1998 Nov 24, 66(2), 173 - 84
T lymphocytes, B lymphocytes, and macrophages in the ovaries and oviducts of laying hens experimentally infected with Salmonella enteritidis; Withanage GS et al.; Subsets of T lymphocytes, B lymphocytes, and macrophages in the ovaries and oviducts of laying hens were enumerated by immunohistochemistry after intravenous inoculation with Salmonella enteritidis . Almost all T cell subsets in the ovaries and different regions of the oviduct increased in number at 7 days post-inoculation and reached a peak by day 10 . This T cell surge was followed by a peak in B cell numbers at day 14 . The number of macrophages declined initially but recovered to preinoculation levels by day 21 . At day 21, the numbers of T and B cells also returned to normal levels, except for IgG+ B cells in the infundibulum, isthmus, and vagina where they remained consistently elevated . The T and B cell proliferation at 10-14 days post-inoculation immediately preceded a decline in the number of S . enteritidis positive tissues from infected hens beginning at day 14 suggesting that these lymphocytes play a major role in the local immune response to S . enteritidis . The Salmonella-oviduct model will be useful for future studies on local immunity to various infectious agents.

J Acquir Immune Defic Syndr Hum Retrovirol, 1998 Dec 15, 19(5), 484 - 9
A prospective study of community-acquired bloodstream infections among febrile adults admitted to Mulago Hospital in Kampala, Uganda; Ssali FN et al.; Septicemia is a frequent cause of death in HIV-infected adults in developing countries . Additional prospective studies are needed to determine the etiology of bloodstream infections (BSI) in febrile HIV-infected adults and guide initial evaluation and treatment in this setting . We assessed the prevalence and etiology of community-acquired BSI among 299 consecutive febrile adult medical admissions to Mulago Hospital, Kampala, Uganda, over a 4-month period in 1997 . The median age of our patients was 30 years, 159 (53%) were male, and 227 (76%) HIV-1-seropositive . Overall, prevalence of bacteremia or fungemia (1 patient) was 24% . Bacteremia was more frequent in HIV-infected than in uninfected patients (27% versus 15%, respectively; p = .04) . Mycobacterium tuberculosis (n = 28), Streptococcus pneumoniae (n = 15) and Salmonella species (n = 13) were the most frequent isolates . All Salmonella and mycobacterial isolates were recovered from HIV-infected patients . Pneumococcal bacteremia was not associated with HIV seropositivity . M . avium complex and M . simiae were isolated from two HIV-infected patients . The rate of mycobacteremia among febrile HIV-infected adults presenting for hospitalization was 13% . Bacteremia and disseminated tuberculosis are frequent causes of morbidity in febrile HIV-infected Ugandan adults . Initial empiric antibiotic coverage in this setting should be targeted toward the pneumococcus and gram-negative enteric bacilli, especially nontyphi Salmonella species . All patients presenting with chronic cough should be evaluated for tuberculosisPIP: Septicemia often causes death in HIV-infected adults in developing countries . The prevalence and etiology of community-acquired bloodstream infections (BSI) were measured among 299 consecutive febrile adult medical admissions to Mulago Hospital, Kampala, Uganda, during 4 months in 1997 . The 299 patients in the final study sample were of median age 30 years, of whom 159 (53%) were male and 227 (76%) were HIV-1-seropositive . The overall prevalence of bacteremia or fungemia was 24%, with 27% of HIV-infected patients and 15% of uninfected patients being bacteremic . 28 people were infected with Mycobacterium tuberculosis, 15 with Streptococcus pneumoniae, and 13 with Salmonella species; these were the most frequent isolates . All Salmonella and mycobacterial isolates were recovered from HIV-infected patients . Pneumococcal bacteremia was not associated with HIV seropositivity . M . avium complex and M . simiae were isolated from 2 patients infected with HIV . 13% of febrile HIV-infected adults who presented for hospitalization were mycobacteremic . These findings suggest that bacteremia and disseminated tuberculosis (TB) are frequent causes of morbidity in febrile HIV-infected Ugandan adults . Initial empiric antibiotic coverage in this setting should target pneumococcus and gram-negative enteric bacilli, while patients presenting with chronic cough should be evaluated for TB .

Scand J Rheumatol, 1998, 27(6), 431 - 4
Persistent or severe course of reactive arthritis following Salmonella enteritidis infection . A prospective study of 9 cases; Kanakoudi-Tsakalidou F et al.; During a 7 year-period 9 children (7 boys, 2 girls) with juvenile reactive arthritis (JReA) due to Salmonella enteritidis (Se) were prospectively studied because of an unusual type of onset and/or course of the disease . The mean duration of JReA activity was 9 +/- 3.6 months . The mean follow-up time was 55.2 +/- 17.4 months . JReA presented as any of the three types of juvenile chronic arthritis (JCA), namely, as asymmetrical oligoarthritis, polyarthritis, or systemic JCA in 5, 2, and 2 patients respectively . Two patients had pericarditis and three developed the complete or incomplete Reiter's syndrome during the disease or during a recurrence . Five patients carried the HLA-B27 and 3/5 developed psoriatic lesions 1 to 15 months after the onset of JReA . The presence of HLA-B27 and psoriasis was associated with a more prolonged course of JReA . However, no patient developed late radiological lesions or sacroiliitis during follow-up.

Carcinogenesis, 1998 Nov, 19(11), 1995 - 2000
Structural determination of a mutagenic aminophenylnorharman produced by the co-mutagen norharman with aniline; Totsuka Y et al.; Norharman (9H-pyrido{3,4-b}indole), widely distributed in our environment, including cigarette smoke and cooked foodstuffs, is not mutagenic to Salmonella strains, but becomes mutagenic to S.typhimurium TA98 and YG1024 with S9 mix in the presence of non-mutagenic aromatic amines such as aniline and o-toluidine . To elucidate the mechanisms of co-mutagenicity, we tried to isolate the mutagen(s) produced by a reaction between norharman and aniline with S9 mix . By HPLC purification, two mutagenic compounds (I and II), one (I) showing mutagenicity with and the other (II) without S9 mix, were isolated . The structure of compound I was deduced to be a coupled compound of norharman and aniline, 9-(4'-aminophenyl)-9H-pyrido{3,4-b}indole (aminophenylnorharman), by a variety of spectrometry techniques and this was confirmed by its chemical synthesis . The mutagenic activity of this novel heterocyclic amine was tested using the pre-incubation method and was found to induce 187,000 revertants in TA98 and 1,783,000 revertants in YG1024 per microg with S9 mix . Compound II was shown to be hydroxyaminophenylnorharman . Formation of the same DNA adducts was observed in YG1024 when aminophenylnorharman or a mixture of norharman plus aniline was incubated with S9 mix . The hydroxyamino derivative also yielded the same DNA adducts in YG1024 . Thus, the appearance of mutagenicity by norharman with aniline in the presence of S9 mix suggests that the coupled mutagenic compound, aminophenylnorharman, is formed from norharman and aniline, then converted to the hydroxyamino derivative and forms DNA adducts to induce mutations in TA98 and YG1024.

Scott Med J, 1998 Oct, 43(5), 146 - 7
Raw egg ingestion and salmonellosis in body builders; Mackenzie AR et al.; Four patients with Salmonella enteritidis infection are reported . All were body builders who regularly consumed substantial quantities of raw eggs . They presented with a severe febrile illness and diarrhoea--presumably reflecting a large bacterial inoculum . Advice regarding the potential hazards of raw egg ingestion has been repeatedly issued by the Department of Health--but this report highlights the fact that this practice continues in spite of this . The epidemiology of S . enteritidis infection in relation to raw egg ingestion is discussed.

J Clin Microbiol, 1999 Jan, 37(1), 266 - 9
Increasing incidence and comparison of nalidixic acid-resistant Salmonella enterica subsp . enterica serotype typhimurium isolates from humans and animals; Heurtin-Le Corre C et al.; We determined the resistance to quinolone of 309 Salmonella enterica subsp . enterica serotype Typhimurium strains isolated from humans and animals (cattle, pigs, or poultry) in 1995 or 1996 . Nalidixic acid resistance increased from 8.5% in 1995 to 18.6% in 1996 . The highest resistance levels correlated with a mutation at Ser-83 (or Asp-82) . All strains remained ciprofloxacin susceptible . Human and animal isolates were compared by pulsed-field gel electrophoresis, and the banding patterns of the human isolates most closely matched those of the bovine isolates.

J Clin Invest, 1998 Dec 15, 102(12), 2035 - 40
Inherited interleukin 12 deficiency in a child with bacille Calmette-Guérin and Salmonella enteritidis disseminated infection; Altare F et al.; Interferon-gamma receptor ligand-binding chain (IFN-gammaR1) or signaling chain (IFN-gammaR2) deficiency, like interleukin 12 receptor beta1 chain (IL-12Rbeta1) deficiency, predispose to severe infections due to poorly virulent mycobacteria and salmonella . A child with bacille Calmette-Guerin and Salmonella enteritidis infection was investigated . Mutations in the genes for IFN-gammaR1, IFN-gammaR2, IL-12Rbeta1, and other molecules implicated in IL-12- or IFN-gamma-mediated immunity were sought . A large homozygous deletion within the IL-12 p40 subunit gene was found, precluding expression of functional IL-12 p70 cytokine by activated dendritic cells and phagocytes . As a result, IFN-gamma production by lymphocytes was markedly impaired . This is the first discovered human disease resulting from a cytokine gene defect . It suggests that IL-12 is essential to and appears specific for protective immunity to intracellular bacteria such as mycobacteria and salmonella.

J Vet Med Sci, 1998 Nov, 60(11), 1233 - 6
Salmonella in broiler chickens in Thailand with special reference to contamination of retail meat with Salmonella enteritidis; Boonmar S et al.; The present study was performed to assess the prevalence of Salmonella in chickens in Thailand . In 1997, 22 serovars of Salmonella were isolated from 72 of 100 chicken meat samples purchased from 10 retail markets in Bangkok and 20 of 200 chicken meat samples from one slaughterhouse for export and 19 of 285 chicken feces obtained from three farms located in the east region of Thailand . The most predominant serovar was S . Enteritidis, which was isolated from 28% of the retail chicken meat, 4.5% of the chicken meat from slaughterhouse, and 6.6% of chickens feces samples examined.

Eur J Biochem, 1998 Nov 15, 258(1), 139 - 43
Structural determination of the O-antigenic polysaccharide from Escherichia coli O35 and cross-reactivity to Salmonella arizonae O62; Rundlof T et al.; The structure of the O-antigenic polysaccharide from Escherichia coli O35 has been investigated with the aid of NMR spectroscopy, sugar and methylation analyses . The sequence of the sugar residues could be determined by NOESY and heteronuclear-multiple-bond-connectivity NMR experiments . The polysaccharide is composed of hexasaccharide repeating units with the following structure, where Rha and GalNAcAN represent rhamnose and 2-acetamido-2-deoxy-galacturonamide, respectively: carbohydrate sequence {see text} . The O-antigen of Escherichia coli O35 is similar to the O-specific polysaccharide from Salmonella arizonae O62, which instead has a terminal 2-acetamido-2-deoxy-alpha-D-galacturonic acid residue . Immunochemical analyses using a rabbit antiserum specific for the Salmonella arizonae O62 O-antigen showed an identical reactivity with both lipopolysaccharides.

Int J Food Microbiol, 1998 Nov 10, 44(3), 219 - 29
Impact on human health of Salmonella spp . on pork in The Netherlands and the anticipated effects of some currently proposed control strategies; Berends BR et al.; The impact on human health of Salmonella spp . on pork in The Netherlands is described . Subsequently, the effects of some currently proposed control strategies in the Dutch pork production chain are evaluated and quantified with the aid of a simple mathematical model . The estimated average incidence of cases of salmonellosis in the Netherlands is about 450 cases per 100,000 person years at risk (pyar) . Some special risk groups for which the risks could be quantified are (1) persons with underlying diseases, such as neoplasms or diabetes mellitus (1200 cases/100,000 pyar); (2) persons with achlorhydria or who excessively use antacids (1100 cases/100,000 pyar); (3) persons who have recently been treated with antibiotics that disturb the normal gut flora (1700 cases/100,000 pyar); (4) nurses (900 cases/100,000 pyar); (5) caterers (900 cases/100,000 pyar); (6) slaughterline personnel (1800 cases/100,000 pyar) . Furthermore, it is estimated that 15% (5-25%) of all cases of salmonellosis in The Netherlands are associated with the consumption of pork . Currently, proposed control measures regarding Salmonella in pigs and on pork in The Netherlands are codes of good manufacturing practices (GMP) that, in fact, formalize recommendations that can be found in many handbooks about pig breeding and pig slaughtering . When evaluated by a mathematical model constructed for this purpose, the proposed GMP codes from farm to cutting/retail could, at best, reduce the current levels of Salmonella-positive pigs and pork by 50-60% . If pigs were bred according to the rather costly specific pathogen-free concept (SPF), the prevalence of contaminated carcasses and pork could in total be reduced by 95% or more . However, implementing GMP codes from the transport phase up to the cutting/retail phase coupled with a decontamination step at the end of the slaughterline would be just as effective as GMP in combination with breeding using the SPF-concept . It is therefore concluded that the most efficient and cost-effective way of reducing the 'Salmonella problem' entailed by the consumption of pork would be to decontaminate carcasses under the precondition that the entire production chain strictly adheres to GMP principles . Therefore, the EU should also allow for more possibilities regarding the decontamination of carcasses than is currently the case . It is also concluded that current EU regulations relying on hazard analysis of critical control points (HACCP)-inspired production in cutting plants will not be effective in reducing the prevalence of Salmonella spp . on pork . This is mainly because (1) there is currently an almost steady stream of Salmonella-positive carcasses that enter the cutting process; (2) when contaminated carcasses are being processed, further cross-contamination during working hours is unavoidable; (3) no steps in the cutting process are intentionally designed to effectively reduce the risks or consequences of cross contamination of cuts and retail-ready products.

Int J Food Microbiol, 1998 Nov 10, 44(3), 207 - 17
Salmonella spp . on pork at cutting plants and at the retail level and the influence of particular risk factors; Berends BR et al.; This article describes the contamination of pork with Salmonella spp . in cutting plants and butchers' shops in The Netherlands and quantifies the influence of several risk factors . When contaminated carcasses are being processed, the main risk factors regarding cross contamination are inapt cleaning and disinfection (OR 12.8), manipulation of contaminated materials as such (OR 4.7) and (re)contaminated surfaces (OR 4.4) . However, in the current situation, where contaminated carcasses are constantly being brought into cutting lines, interim cleaning and disinfection of surfaces and utensils during breaks and at the end of the working day will most likely prevent not more than about 10% of all cross contamination that takes place during a working day . Thus, as long as contaminated carcasses are being processed, about 90% of the cross contamination that occurs in cutting plants is practically unavoidable . It can therefore also be concluded that under these circumstances the implementation of codes of good manufacturing practices (GMP) and Hazard Analysis Critical Control Point (HACCP)-inspired production methods will only be marginally effective in the control of Salmonella spp . cross contamination in cutting lines . The same is more or less true for the processing of contaminated cuts or carcasses by butchers in shops and supermarkets . Furthermore, in contrast to the situation in cutting plants, it may be that up to 10% of butcher's shops or kitchens of restaurants become colonized for several weeks or months with their own endemic 'house flora' of Salmonella spp., which are originally introduced via the purchased contaminated products of animal origin . Though there are no hard data to substantiate this, it can be suspected that these shops and restaurants represent the more badly managed, i.e . poorly cleaned and disinfected, enterprises . However, several analytical limitations hinder an exact determination of the prevalence of Salmonella spp . contaminated pork and an exact quantification the influence of risk factors . The diagnostic value (i.e . the sensitivity, specificity, precision and predictive value) of the combination of swabbing of carcasses and cuts and the usually employed culturing methods, in particular, is largely unknown, and there are indications that it may be seriously questioned . Without a more thorough knowledge about the diagnostic value of current and future methods of sampling and identification, it is impossible to provide for more accurate estimations of the prevalence of Salmonella positive carcasses and cuts . Based on the research data, the incidence of contaminated cuts and retail-ready pork can not be estimated more precise than as somewhere between 5-40% . When compensating for the discussed methodological flaws, it must be assumed that currently the true prevalence of contaminated primal cuts and retail-ready pork in butchers' shops is about 25-30%, and that of minced pork and pork sausages about 50-55% . Lastly it is concluded that if carcasses were Salmonella-free, consumers could in principle be provided with virtually Salmonella-free pork . It is therefore recommended that the EU allows for a decontamination step in slaughterhouses with a substance that is generally recognized as safe, provided that the producers strictly adhere to GMP-principles.

Int J Food Microbiol, 1998 Nov 10, 44(3), 171 - 88
Nonacid meat decontamination technologies: model studies and commercial applications; Sofos JN et al.; Increased consumer awareness and concern about microbial foodborne diseases has resulted in intensified efforts to reduce contamination of raw meat, as evidenced by new meat and poultry inspection regulations being implemented in the United States . In addition to requiring operation of meat and poultry slaughtering and processing plants under the principles of the hazard analysis critical control point (HACCP) system, the new regulations have established microbiological testing criteria for Escherichia coli and Salmonella, as a means of evaluating plant performance . These developments have renewed and intensified interest in the development and commercial application of meat and poultry decontamination procedures . Technologies developed and evaluated for decontamination include live animal cleaning/washing, chemical dehairing, carcass knife-trimming to remove physical contaminants, steam/hot water-vacuuming for spot-cleaning/decontamination of carcasses, spray washing/rinsing of carcasses with water of low or high pressures and temperatures or chemical solutions, and exposure of carcass sides to pressurized steam . Under appropriate conditions, the technologies applied to carcasses may reduce mean microbiological counts by approximately one-three log colony forming units (cfu)/cm2, and some of them have been approved and are employed in commercial applications (i.e., steam-vacuuming; carcass spray-washing with water, chlorine, organic acid or trisodium phosphate solutions; hot water deluging/spraying/rinsing, and pressurized steam) . The contribution of these decontamination technologies to the enhancement of food safety will be determined over the long term, as surveillance data on microbial foodborne illness are collected . This review examines carcass decontamination technologies, other than organic acids, with emphasis placed on recent advances and commercial applications.

J AOAC Int, 1998 Nov-Dec, 81(6), 1147 - 54
Performance tested method certification of BAX for Screening/Salmonella: a case study; Mrozinski PM et al.; This report details the independent laboratory study of the BAX for Screening/Salmonella assay to complete AOAC Performance Tested Method certification . The performance of the BAX system was compared with those of BAM culture methods on food samples inoculated with Salmonella . This study validated product claims . Performance Tested Method status was granted for the screening assay.

FEMS Immunol Med Microbiol, 1998 Nov, 22(3), 263 - 73
Comparison of the effects of Salmonella minnesota Re595 lipopolysaccharide, lipid A and monophosphoryl lipid A on nitric oxide, TNF-alpha, and IL-6 induction from RAW 264.7 macrophages; Aybay C et al.; Lipopolysaccharide (LPS) exhibits a wide variety of bioactivities . Although it was generally proposed that the lipid A component represented the active center responsible for most of the bioactivities of LPS, a variety of lipid A partial structures and analogues were reported to have different properties . Lipopolysaccharide of the Re595 mutant of Salmonella minnesota is lack of O and part of the core polysaccharide (2 keto-3-deoxyoctanate (KDO) left on lipid A) . Re595 lipid A (LA) and Re595 monophosphoryl lipid A (MPLA) differ in structure from Re595 LPS by lacking KDO and KDO plus phosphoryl group respectively . Whether these lipid A-common Re595 LPS preparations differed in activities, we investigated their effects on nitric oxide (NO), TNF-alpha, IL-6, and IL-12 induction from murine macrophage cell line RAW 264.7 . RAW 264.7 cells (2 x 10(5) cells ml(-1)) were stimulated with these LPS preparations at 1 microg ml(-1) for 48 h . Re595 LPS, Re595 LA and Re595 MPLA significantly induced NO, TNF-alpha and IL-6 production; NO, TNF-alpha and IL-6 inducing capacities were in the order of LPS = LA > MPLA, LPS = LA = MPLA, and LPS = LA > MPLA respectively . However, these preparations did not induce IL-12 production from RAW cells even when stimulated in combination with IFN-gamma (20 U ml(-1)) . IFN-gamma itself also induced NO, TNF-alpha and IL-6 production from RAW 264.7 cells . When RAW 264.7 cells were stimulated with IFN-gamma plus any of these preparations, effects were additive and synergistic for NO and IL-6 responses respectively . But TNF-alpha responses of RAW cells against these preparations were almost equal when cultured alone or in combination with IFN-gamma . Pre-treatment of RAW cells either with LPS, LA or MPLA at low concentration (0.1 microg ml(-1)) for 60 min before pulsing with IFN-gamma (20 IU ml(-1)) plus LPS (1 microg ml(-1)) for an additional 48 h, significantly (P < 0.01) decreased NO response . Although to a lesser extent, TNF-alpha and IL-6 responses were also decreased . Complete inhibition of NO inducing effect of these LPS preparations was achieved with polymyxin B at 40 microg ml(-1) . But the concentration of polymyxin B to get a significant (P < 0.05) inhibitory effect on LPS was four times higher than that for LA or MPLA . Unexpectedly, polymyxin B also inhibited INF-gamma-induced NO production from RAW cells in a dose-dependent fashion . These findings suggested that effect of LPS was dependent, at least in part, on both the LPS polysaccharide chain length and the hydrophilic portion of LPS . In addition, not only LPS but also LA and MPLA exert either enhancing or suppressive effects, depending on their concentrations and the timing of their addition with respect to co-stimulators.

FEMS Immunol Med Microbiol, 1998 Nov, 22(3), 233 - 9
A highly sensitive and fast non-radioactive method for the detection of polymerase chain reaction products from Salmonella serovars, such as Salmonella typhi, in blood specimens; Cocolin L et al.; A polymerase chain reaction based test was developed for the detection of Salmonella spp . in blood specimens . After amplification of a 389 bp-polymerase chain reaction product from the invA gene, a microtiter plate hybridization assay was performed . The protocol described allowed the detection of six to seven copies of the Salmonella typhi genome, as determined by serial dilutions of DNA from S . typhi . Eighteen blood specimens from artificially infected rats and 22 blood specimens from patients were analyzed to validate the method . Considering that the most frequent Salmonella serovar isolated from blood in case of bacteremia is S . typhi, the polymerase chain reaction-microtiter plate hybridization technique could be used as a novel, rapid diagnostic method for typhoid fever, particularly when standard culture assays are negative.

Int J Tuberc Lung Dis, 1998 Nov, 2(11), 926 - 34
Spectrum of disease among HIV-infected adults hospitalised in a respiratory medicine unit in Abidjan, Côte d'Ivoire; Grant AD et al.; SETTING: Respiratory medicine wards of the University Teaching Hospital, Abidjan, Cote d'Ivoire . OBJECTIVES: To describe the spectrum of opportunistic infection among human immunodeficiency virus (HIV) infected adults hospitalised in the respiratory medicine unit in Abidjan, and the level of immunosuppression at which these diseases occur . DESIGN: Cross-sectional study . RESULTS: Overall, 75% of patients were HIV-positive: among these patients, the most frequent diagnosis was tuberculosis, in 61%, followed by bacterial pneumonia (15%), Gram-negative septicaemia (particularly non-typhoid Salmonella) (9%) and empyema (5%) . Atypical pneumonias appeared to be rare . Most HIV-positive patients had CD4 counts indicative of advanced immunosuppression: 36% had CD4 counts below 100 x 10(6)/l, 19% between 100 and 199 x 10(6)/l, 29% between 200 and 499 x 10(6)/l, and 16% above 500 x 10(6)/l . Overall in-hospital mortality was 27% for HIV-positive patients and 22% for HIV-negative patients (P = 0.5) . In a multivariate analysis, the strongest independent risk factors for death were cachexia (odds ratio {OR} 7.4, 95% confidence interval {CI} 2.1-26.3), male sex (OR 4.5, 95% CI 1.2-17.4) and age over 40 (OR 4.1, 95% CI 1.0-17.2) . CONCLUSIONS: Tuberculosis and bacterial infections are the major causes of respiratory morbidity in immunosuppressed HIV-infected adults in this population . Efforts to improve the management of HIV-related disease need to focus on prevention and treatment of these infections.

Onderstepoort J Vet Res, 1998 Jun, 65(2), 67 - 73
Comparison of immune responses of two Salmonella gallinarum strains viewed as possible vaccines for fowl typhoid in Kenya; Bebora LC et al.; The immune responses of two S . gallinarum strains, L46 and CN 180, were compared in 15-week-old cockerels . The humoral and cell-mediated immune responses were assayed by means of the indirect haemagglutination test (IHA) and the macrophage migration inhibition test (MIT), respectively . Birds were vaccinated with the two vaccines, respectively, and bled for sera (for IHA) and cells (for MIT) every week up to the seventh week, post vaccination, then every alternate week, three times, and later once every month, for a total period of 37 weeks . Strain L46 was found to induce an immune response that was very similar to that of CN 180 . Both gave good humoral and cellular responses.

Onderstepoort J Vet Res, 1997 Dec, 64(4), 277 - 83
Salmonella isolated from crocodiles and other reptiles during the period 1985-1994 in South Africa; van der Walt ML et al.; Over a 10-year period, 173 isolates of Salmonella were obtained during routine isolation from reptiles . Of the 173 isolates, 92 different Salmonella serovars were identified . Of them, 61 (66%) belonged to subspecies I, nine to subspecies II and 21 to subspecies III (IIIa and IIIb), and one to subspecies IV . The majority of isolates were from farmed Nile crocodiles (145), three from wild-caught African dwarf crocodiles, 11 from captive snakes, 13 from lizards and one from a tortoise . The isolates from the tortoise and lizards were subspecies I isolates (Zaire and Tsevie, respectively) . Of the snakes, nine isolates were S.III . The serovars isolated most often from the crocodiles were of subspecies I (32 serovars) . Eight were from subspecies II, seven from subspecies III and one from subspecies IV . The most frequently identified serovars were Typhimurium (seven), Tsevie (six), Duval (six), Schwerin (six), Tinda (six), and Tallahassee (six) . On two commercial crocodile breeding farms that had experienced ongoing problems for about two years, many isolates of Salmonella were made . Some of these serovars were isolated more than once, and also months apart . No single Salmonella serovar predominated, nor did a single pathological condition . These salmonellas were predominantly of subspecies I.

Biosens Bioelectron, 1998 Nov 1, 13(10), 1091 - 7
Thiolated Salmonella antibody immobilization onto the gold surface of piezoelectric quartz crystal; Park IS et al.; An improved antibody-coated sensor system based on quartz crystal microbalance analysis on Salmonella spp . was developed making use of thiolated antibody immobilization onto one gold electrode of the piezoelectric quartz crystal surface . The best results in sensitivity and stability were obtained with the thin layer of a thiol-cleavable, heterobifunctional cross-linker, sulfosuccinimidyl 6-{3-(2-pyridyldithio)propionamido}hexanoate (sulfo-LC-SPDP) . The long bridge of this reagent could function as a spacer, facilitating antibody-Salmonella interaction on the gold electrode . After the addition of a S . typhimurium suspension into a reaction cell with 0.1 M sodium phosphate buffer, pH 7.2, the resonant frequency decreased conspicuously . The time required for maximum frequency shift was about 30-90 min . Sensor response was observed for the microbial suspensions ranging from 9.9 x 10(5) to 1.8 x 10(8) CFU/ml.

J Immunol Methods, 1998 Nov 1, 220(1-2), 39 - 49
The role of valency in the selection of anti-carbohydrate single-chain Fvs from phage display libraries; MacKenzie R et al.; Several strategies were investigated for phage display of anti-carbohydrate single-chain Fvs (scFvs) using the anti-Salmonella Se155-4 scFv as a model system . All were based on the knowledge that panning V(H) CDR libraries displayed in a standard pIII phagemid/helper phage format against immobilized multivalent carbohydrate antigens selects almost solely for mutants with higher yields of soluble product or scFvs that form dimers or higher oligomers even when the linker length is chosen to give monomeric molecules . Construction of scFv libraries, in a phagemid vector, with mutations that already provide higher yields and/or short linkers to promote dimeric display greatly reduced these undesired selection pressures . However . the panning of an error-prone library of the entire scFv in a short linker format yielded two mutants that existed partially in higher oligomeric forms, indicating that dimeric display did not entirely eliminate the selection pressure problem . In one mutant a Ser75Gly mutation led to the formation of greater amounts of dimeric, trimeric and tetrameric scFv and surface plasmon resonance analysis of these different forms gave quantitative data for the functional affinity of these different scFv forms . Finally, a phage vector was constructed and the original V(H) CDR library was transferred to this vector . This display format, in which scFv is displayed on all three to five copies of pIII, seemed to be superior in terms of selection on the basis of binding site affinity and as a display mode for scFvs with low intrinsic affinity . While the use of the phage vector did not lead to the isolation of higher affinity binders from the library employed here, it did almost entirely remove the undesired selection pressures in that there was selection for the wild-type sequence . It is suggested that the multivalency of display provided by phage vectors is preferable to any phagemid vector strategy for the de novo isolation of anti-carbohydrate antibodies from phage libraries.

J Dairy Sci, 1998 Nov, 81(11), 3029 - 35
Key health issues for dairy cattle--new and old; Wells SJ et al.; The objective of this paper is to use available information to evaluate the relative importance of various health issues affecting dairy cattle . In addition to traditional ranking using evaluation methods based on impacts to animal productivity, this paper considers zoonotic risks, international trade implications, and animal welfare concerns . Traditional production costs rank mastitis, reproductive problems, and lameness as the top dairy cattle diseases . When the other areas of importance are included, the top-ranked diseases change to include salmonella, Johne's disease, bovine viral diarrhea-associated disease, and mastitis . Researchers in the dairy industry may want to reevaluate their criteria for setting research priorities to include zoonotic risks, international trade implications, and animal welfare concerns.

J Dairy Sci, 1998 Nov, 81(11), 2798 - 803
Evaluation of universal preenrichment broth for the recovery of foodborne pathogens from milk and cheese; Jiang J et al.; The use of universal preenrichment broth for the recovery of verotoxigenic Escherichia coli, Salmonella spp., and Listeria monocytogenes from milk and cheese was examined . Universal preenrichment broth supported the growth of low inoculum levels (10 cfu/ml) of these organisms in pure cultures and in mixed cultures containing higher levels of other pathogens or bacterial flora from raw milk . This medium also supported the recovery and growth of heat-injured Salmonella spp., L . monocytogenes, and verotoxigenic E . coli at inoculum levels of 10(2) cfu/ml to yield cell levels of 10(8) cfu/ml in pure cultures and at least 10(5) cfu/ml in the presence of high levels of known competitive pathogens or microflora of cheese samples after 24 h of incubation . Universal preenrichment broth performed better than Listeria enrichment broth in supporting the recovery and growth of heat-injured L . monocytogenes and equally as well as buffered peptone water or trypticase soy broth in supporting the growth of uninjured L . monocytogenes, Salmonella spp., and verotoxigenic E . coli . Coenrichment of these pathogens in universal preenrichment broth reduced the quantity of milk or cheese samples that were required for analysis and also reduced the cost and labor involved in preparing and processing separate preenrichment media.

Mutat Res, 1998 Dec 3, 422(2), 347 - 50
Human developmental toxicity and mutagenesis; Rosenkranz HS et al.; A previously described SAR model of human developmental toxicity was analyzed further . The model shows a number of mechanistic similarities with SAR models of other toxicological phenomena (systemic toxicity, chromosomal and genomic effects) . This implies that there are many targets associated with developmental effects . Surprisingly the analyses revealed no significant mechanistic overlap between developmental toxicity in humans and mutagenicity in Salmonella, a surrogate for the occurrence of point mutations . Our study indicates that this lack of similarity is likely the result of the pre-screening strategies which largely eliminate Salmonella mutagens from among the therapeutics introduced into human medicine .

Mutat Res, 1998 Dec 3, 420(1-3), 15 - 25
Mutagenicity assay in Salmonella and in vivo sister chromatid exchange in bone marrow cells of mice for four pyrazolone derivatives; Giri AK et al.; Phenylbutazone (PB), oxyphenbutazone (OPB), antipyrine (AP) and dipyrone (DP) are four important pyrazolone derivatives mainly used as anti-inflammatory, antipyretic and analgesic drugs . At present these are the most widely used pyrazolone derivatives throughout the world . The widespread use of these drugs are of great concern for human health problems . In the present study these four drugs were tested in mutagenicity assays in Salmonella strains TA97a, TA98, TA100 and TA102 using a plate incorporation assay both with and without S-9 mix and for in vivo sister chromatid exchanges (SCE) in bone marrow cells of mice . The first three drugs were negative in all the tester strains but dipyrone showed a weak mutagenic activity at higher concentrations in all four strains both with and without metabolic activation . In the in vivo SCE assay in male mice, all four drugs showed a statistically significant increase in SCE in bone marrow cells when compared with control .

Antimicrob Agents Chemother, 1998 Dec, 42(12), 3053 - 8
Class 1 integron-borne multiple-antibiotic resistance carried by IncFI and IncL/M plasmids in Salmonella enterica serotype typhimurium; Tosini F et al.; The presence and genetic content of integrons were investigated for 37 epidemiologically unrelated multiple-drug-resistant strains of Salmonella enterica serotype Typhimurium from humans . All isolates were resistant to ampicillin, chloramphenicol, kanamycin, streptomycin, sulfonamides, and trimethoprim, as well as to tetracycline and/or nalidixic acid; 20% of them were also resistant to gentamicin and amikacin . Three different class 1 integrons (In-t1, In-t2, and In-t3) were identified by Southern blot hybridization, PCR, and DNA sequencing, and these integrons were found to carry the aadB, catB3, oxa1, aadA1a, aacA4, and aacC1 gene cassettes . Integrons In-t1 (aadB and catB3) and In-t2 (oxa1 and aadA1a) were both located on a conjugative IncFI plasmid of 140 kb . In-t3 (aacA4, aacC1, and aadAIa) was located on an IncL/M plasmid of 100 kb which was present, in association with the IncFI plasmid, in gentamicin- and amikacin-resistant isolates . Despite the extensive similarity at the level of the antibiotic resistance phenotype, integrons were not found on the prototypic IncFI plasmids carried by epidemic Salmonella strains isolated during the late 1970s . The recent appearance and the coexistence of multiple integrons on two conjugative plasmids in the same Salmonella isolate are examples of how mobile gene cassettes may contribute to the acquisition and dissemination of antibiotic resistance.

J Food Prot, 1998 Nov, 61(11), 1507 - 10
Performance of the Dynabeads anti-Salmonella system in the detection of Salmonella species in foods, animal feeds, and environmental samples; Shaw SJ et al.; The immunomagnetic separation Dynabeads anti-Salmonella technique was evaluated for the detection of Salmonella species in a variety of foods, feeds, and environmental samples . Salmonella cells in preenrichment broths were captured using the Dynabeads anti-Salmonella system and were then washed and plated on indicator media . A total of 308 naturally contaminated samples were analyzed, including 46 cheese and egg products, 183 animal feeds, and 79 environmental swabs . The results of the Dynabeads method gave 100% correlation with the results of the standard culture technique used for foods and the modified semisolid Rappaport-Vassiliadis method used for feeds and environmental samples.

J Food Prot, 1998 Nov, 61(11), 1504 - 6
Comparison of enrichment methods for recovery and chick infectivity of chlorine-injured Salmonella enteritidis; Sarlin LL et al.; In recent years, several preenrichment media have been shown to be effective for use in the recovery of sublethally injured Salmonella organisms . Selective enrichment without preenrichment has resulted in a lower recovery of organisms, particularly with regard to injured or stressed salmonellae . The present experiments compared the ability of nonselective preenrichment followed by selective enrichment or direct selective enrichment alone to recover chlorine-injured Salmonella organisms . Additionally, the Salmonella detection limits of the two enrichment methods were compared with minimal infectious dose in neonatal chicks . In three experiments, Salmonella enteritidis cells were exposed to chlorine for specific times and subsequently cultured by using preenrichment followed by selective enrichment or selective enrichment alone . Simultaneously, neonatal chicks were orally challenged with S . enteritidis cells from each exposure time to chlorine . The results indicated a marginal, but significantly (P < 0.05) higher level of recovery of sublethally injured salmonellae by using nonselective preenrichment followed by selective enrichment, as compared to selective enrichment alone . Interestingly, both culture methods were capable of detecting injured S . enteritidis cells at levels incapable of infecting neonatal chicks.

Proc Natl Acad Sci U S A, 1998 Nov 24, 95(24), 14057 - 9
SopB, a protein required for virulence of Salmonella dublin, is an inositol phosphate phosphatase; Norris FA et al.; Several proteins secreted by enteric bacteria are thought to contribute to virulence by disturbing the signal transduction of infected cells . Here, we report that SopB, a protein secreted by Salmonella dublin, has sequence homology to mammalian inositol polyphosphate 4-phosphatases and that recombinant SopB has inositol phosphate phosphatase activity in vitro . SopB hydrolyzes phosphatidylinositol 3,4,5-trisphosphate, an inhibitor of Ca2+-dependent chloride secretion . In addition, SopB hydrolyzes inositol 1,3,4,5,6 pentakisphosphate to yield inositol 1,4,5, 6-tetrakisphosphate, a signaling molecule that increases chloride secretion indirectly by antagonizing the inhibition of chloride secretion by phosphatidylinositol 3,4,5-trisphosphate {Eckmann, L., Rudolf, M . T., Ptasznik, A., Schultz, C., Jiang, T., Wolfson, N., Tsien, R., Fierer, J., Shears, S . B., Kagnoff, M . F., et al . (1997) Proc . Natl . Acad . Sci . USA 94, 14456-14460} . Mutation of a conserved cysteine that abolishes phosphatase activity of SopB results in a mutant strain, S . dublin SB c/s, with decreased ability to induce fluid secretion in infected calf intestine loops . Moreover, HeLa cells infected with S . dublin SB c/s do not accumulate high levels of inositol 1,4,5,6-tetrakisphosphate that are characteristic of wild-type S . dublin-infected cells . Therefore, SopB mediates virulence by interdicting inositol phosphate signaling pathways.

Infect Immun, 1998 Dec, 66(12), 5599 - 606
Molecular and functional characterization of Salmonella enterica serovar typhimurium poxA gene: effect on attenuation of virulence and protection; Kaniga K et al.; Salmonella enterica poxA mutants exhibit a pleiotropic phenotype, including reduced pyruvate oxidase activity; reduced growth rate; and hypersensitivity to the herbicide sulfometuron methyl, alpha-ketobutyrate, and amino acid analogs . These mutants also failed to grow in the presence of the host antimicrobial peptide, protamine . In this study, PoxA- mutants of S . enterica serovar Typhimurium (S . typhimurium) were found to be 10,000-fold attenuated in orally inoculated BALB/c mice and 1,000-fold attenuated in intraperitoneally inoculated BALB/c mice, compared to wild-type S . typhimurium UK-1 . In addition, poxA mutants were found to be capable of colonizing the spleen, mesenteric lymph nodes, and Peyer's patches; to induce strong humoral immune responses; and to protect mice against a lethal wild-type Salmonella challenge . A 2-kb DNA fragment was isolated from wild-type S . typhimurium UK-1 based on its ability to complement an isogenic poxA mutant . The nucleotide sequence of this DNA fragment revealed an open reading frame of 325 amino acids capable of encoding a polypeptide of 36.8 kDa that was confirmed in the bacteriophage T7 expression system . Comparison of the translated sequence to the available databases indicated high homology to a family of lysyl-tRNA synthetases . Our results indicate that a mutation of poxA has an attenuating effect on Salmonella virulence . Further, poxA mutants are immunogenic and could be useful in designing live vaccines with a variety of bacterial species . To our knowledge, this is the first report on the effect of poxA mutation on bacterial virulence.

Infect Immun, 1998 Dec, 66(12), 5799 - 804
Secreted effector proteins of Salmonella dublin act in concert to induce enteritis; Jones MA et al.; The ability of enteropathogenic salmonellae to recruit inflammatory cells and induce secretory responses in the infected ileum is considered to be a main feature in Salmonella-induced enteritis . Interactions between the pathogen and intestinal epithelial cells result in a variety of cellular responses mediating inflammation and fluid secretion . It is becoming apparent that proteins secreted by the Inv-Spa type III secretion system of Salmonella spp . play a key role in the induction of these responses . We have recently demonstrated that the SopB effector protein is translocated into eukaryotic cells via a Sip-dependent pathway and mediates inflammation and fluid secretion in infected ileal mucosa . However, SopB did not appear to be the only effector involved, as inactivation of the sopB gene only partially impaired enteropathogenicity . We suggested that at least some of such protein effectors are likely to be proteins of the same class as SopB, i.e., secreted effector proteins translocated into eukaroyotic cells via a Sip-dependent pathway . In this work, we identify SopD, another secreted protein belonging to the family of Sop effectors of Salmonella dublin . Using the cya reporter system we showed that SopD is translocated into eukaroyotic cells . We assessed the potential involvement of SopD in enteropathogenicity and found that inactivation of sopD has an additive effect in relation to the sopB mutation.

Infect Immun, 1998 Dec, 66(12), 5630 - 5
Differences in immune responses induced by oral and rectal immunizations with Salmonella typhi Ty21a: evidence for compartmentalization within the common mucosal immune system in humans; Kantele A et al.; Based on the concept of the common mucosal immune system, immunization at various inductive sites can induce an immune response at other, remote mucosal surfaces . The immune responses elicited through rectal and oral routes of antigen delivery were compared with respect to (i) measurement of antibody responses in serum and various external secretions of the vaccinees and (ii) characterization of the nature and homing potentials of circulating antibody-secreting cells (ASC) . Specific ASC appeared in the circulation in 4 of 5 volunteers after oral and 9 of 11 volunteers after rectal immunization with Salmonella typhi Ty21a . The kinetics, magnitude, and immunoglobulin isotype distribution of the ASC responses were similar in the two groups . In both groups, almost all ASC (99 or 95% after oral or rectal immunization, respectively) expressed alpha4 beta7, the gut homing receptor (HR), whereas L-selectin, the peripheral lymph node HR, was expressed only on 22 or 38% of ASC, respectively . Oral immunization elicited a more pronounced immune response in saliva and vaginal secretion, while rectal immunization was more potent in inducing a response in nasal secretion, rectum, and tears . No major differences were found in the abilities of the two immunization routes to induce a response in serum or intestinal secretion . Thus, the rectal antigen delivery should be considered as an alternative to the oral immunization route . The different immune response profiles found in various secretions after oral versus rectal antigen administration provide evidence for a compartmentalization within the common mucosal immune system in humans.

Infect Immun, 1998 Dec, 66(12), 5620 - 9
Large-scale identification of virulence genes from Streptococcus pneumoniae; Polissi A et al.; Streptococcus pneumoniae is the major cause of bacterial pneumonia, and it is also responsible for otitis media and meningitis in children . Apart from the capsule, the virulence factors of this pathogen are not completely understood . Recent technical advances in the field of bacterial pathogenesis (in vivo expression technology and signature-tagged mutagenesis {STM}) have allowed a large-scale identification of virulence genes . We have adapted to S . pneumoniae the STM technique, originally used for the discovery of Salmonella genes involved in pathogenicity . A library of pneumococcal chromosomal fragments (400 to 600 bp) was constructed in a suicide plasmid vector carrying unique DNA sequence tags and a chloramphenicol resistance marker . The recent clinical isolate G54 was transformed with this library . Chloramphenicol-resistant mutants were obtained by homologous recombination, resulting in genes inactivated by insertion of the suicide vector carrying a unique tag . In a mouse pneumonia model, 1.250 candidate clones were screened; 200 of these were not recovered from the lungs were therefore considered virulence-attenuated mutants . The regions flanking the chloramphenicol gene of the attenuated mutants were amplified by inverse PCR and sequenced . The sequence analysis showed that the 200 mutants had insertions in 126 different genes that could be grouped in six classes: (i) known pneumococcal virulence genes; (ii) genes involved in metabolic pathways; (iii) genes encoding proteases; (iv) genes coding for ATP binding cassette transporters; (v) genes encoding proteins involved in DNA recombination/repair; and (vi) DNA sequences that showed similarity to hypothetical genes with unknown function . To evaluate the virulence attenuation for each mutant, all 126 clones were individually analyzed in a mouse septicemia model . Not all mutants selected in the pneumonia model were confirmed in septicemia, thus indicating the existence of virulence factors specific for pneumonia.

Epidemiol Infect, 1998 Oct, 121(2), 295 - 301
Pathogenicity in isolates of Salmonella enterica serotype Enteritidis PT4 which differ in RpoS expression: effects of growth phase and low temperature; Humphrey TJ et al.; Experiments with 2 wild type isolates of Salmonella enterica serotype Enteritidis PT4, which differed in RpoS expression, tolerance to certain hostile environments and pathogenicity, found that changes in in vitro acid, heat, or peroxide tolerance had no effect on the ability of the isolates to multiply in the spleens of C57/BL7/J mice infected orally . Thus, with the pathogenic RpoS-positive isolate, the infectivity of log phase chilled cells, which are profoundly acid-sensitive, was the same as that of non-chilled stationary phase cells which are acid-tolerant . Similarity the infectivity of the RpoS-negative, sensitive isolate, was not enhanced by increases in any tolerance . The ability to survive on surfaces, like infectivity, was also largely unaffected by either growth phase or cold exposure . These two attributes may thus be related and, given that the pathogenic PT4 isolate is capable of prolonged survival and the nonpathogenic isolate survives poorly, survival could serve as a potential marker of pathogenicity . Although the pathogenicity of the two isolates was very different, they showed an almost identical increase in acid tolerance following culture at pH 4.0 for up to 60 min.

Epidemiol Infect, 1998 Oct, 121(2), 289 - 93
Molecular fingerprinting defines a strain of Salmonella enterica serotype Anatum responsible for an international outbreak associated with formula-dried milk; Threlfall EJ et al.; Molecular analyses based on plasmid profile typing and pulsed-field gel electrophoresis have defined a strain of Salmonella enterica serotype Anatum associated with the consumption of a particular brand of formula-dried milk responsible for an outbreak in late 1996/early 1997 involving 15 infants and 2 relatives in the UK, and 2 infants in France . The study has demonstrated the value of laboratory-based surveillance involving identification of the outbreak strain at the molecular level coupled with food microbiology and targeted epidemiological investigations, and has highlighted the importance of rapid communication and subsequent international collaboration through the European Union-funded Salm-Net salmonella surveillance network.

Zh Mikrobiol Epidemiol Immunobiol, 1998 Sep-Oct, (5), 22 - 5
{Development of principles for the controlled autolysis of Escherichia and Salmonella}; Akaizin ES; The autolysis of Escherichia and Salmonella, depending on the conditions of the medium where the cultivation and lysis of the bacteria took place, was studied . The study revealed that the autolysis of these bacteria was most intensive if lysis was induced at the moment when the culture achieved the maximum specific growth rate, as well as in case when the extreme conditions were maintained in the medium during the autolytic process . Approaches to controlling the process of the induced autolysis of Escherichia and Salmonella were proposed and substantiated.

Zh Mikrobiol Epidemiol Immunobiol, 1998 Sep-Oct, (5), 17 - 9
{Experimental study of mixed infection by Vibrio cholerae and Salmonella typhi}; Lobanov VV et al.; Mixed infection caused by V.cholerae and S.typhi was studied on guinea pig gall-bladder, used as an experimental model . These microorganisms coexisted in association in animals and exhibited no pronounced antagonistic properties in vitro . The cultures isolated from the organs of infected guinea pigs did not differ from initial ones . The study revealed that in nutrient broth containing 50% of dried bile salmonellae were preserved, but not V.cholerae . The latter could co-exist with S.typhi in 1% biliary medium prepared on meat-peptone broth (MPB) . The use of bile and MPB as the basis for media intended for the study of material obtained from cholera and typhoid fever patients is recommended.

FEBS Lett, 1998 Oct 30, 438(1-2), 15 - 20
The effect of the lipid A analog E5531 on phospholipid membrane properties; Asai Y et al.; In order to determine the effect of the lipid A analog, E5531, on phospholipid membranes, we used dipalmitoylphosphatidylcholine (DPPC) and investigated the physicochemical interaction between E5531 and DPPC membranes . E5531 and DPPC are miscible in the bulk phase at 25 degrees C . Within the E5531 mole fraction range (X(E5531)) of 0-0.5, E5531 decreased the zeta potentials of DPPC membranes but did not change the size of the DPPC liposomes . E5531/DPPC mixtures formed liposome-like structures . E5531 increased the fluidity of the DPPC membrane and decreased pyrene diffusion in the membrane . E5531 decreased the phase transition temperature and the cooperative interactions between DPPC molecules . These effects of E5531 on phospholipid membranes were different from those of lipid A from Escherichia coli and Salmonella minnesota.

Cornea, 1998 Nov, 17(6), 672 - 4
Peripheral ulcerative keratitis after Salmonella gastroenteritis; Yang J et al.; PURPOSE: To describe a case of bilateral peripheral ulcerative keratitis after Salmonella gastroenteritis . METHODS: Case report with description of treatment and outcome . RESULTS: The peripheral ulcerative keratitis gradually resolved in both eyes after appropriate systemic antibiotic therapy and local ocular care . CONCLUSION: Peripheral ulcerative keratitis can result as a consequence of infectious gastroenteritis.

J Clin Invest, 1998 Nov 15, 102(10), 1815 - 23
Apoptosis of human intestinal epithelial cells after bacterial invasion; Kim JM et al.; Epithelial cells that line the human intestinal mucosa are the initial site of host invasion by bacterial pathogens . The studies herein define apoptosis as a new category of intestinal epithelial cell response to bacterial infection . Human colon epithelial cells are shown to undergo apoptosis following infection with invasive enteric pathogens, such as Salmonella or enteroinvasive Escherichia coli . In contrast to the rapid onset of apoptosis seen after bacterial infection of mouse monocyte-macrophage cell lines, the commitment of human intestinal epithelial cell lines to undergo apoptosis is delayed for at least 6 h after bacterial infection, requires bacterial entry and replication, and the ensuing phenotypic expression of apoptosis is delayed for 12-18 h after bacterial entry . TNF-alpha and nitric oxide, which are produced as components of the intestinal epithelial cell proinflammatory program in the early period after bacterial invasion, play an important role in the later induction and regulation of the epithelial cell apoptotic program . Apoptosis in response to bacterial infection may function to delete infected and damaged epithelial cells and restore epithelial cell growth regulation and epithelial integrity that are altered during the course of enteric infection . The delay in onset of epithelial cell apoptosis after bacterial infection may be important both to the host and the invading pathogen since it provides sufficient time for epithelial cells to generate signals important for the activation of mucosal inflammation and concurrently allows invading bacteria time to adapt to the intracellular environment before invading deeper mucosal layers.

J Infect, 1998 May, 36(3), 289 - 95
Reactive arthritis following an outbreak of Salmonella Bovismorbificans infection; Mattila L et al.; A large, single-source Salmonella outbreak caused by a rare serovar Bovismorbificans (6,8:r:1,5) occurred in southern Finland in 1994 . The origin of the outbreak was sprouted alfalfa seeds . A questionnaire was mailed to all 210 subjects with positive stool culture . Ninety-one percent (191/210) returned the questionnaire . One hundred and fifty-three (80%) were adults . One hundred and fifty-nine out of one hundred and ninety-one (83%) reported diarrhoea, 109 (57%) fever, 104 (54%) abdominal pains, 83 (43%) fatigue, 66 (35%) articular symptoms and 20 (10%) had no symptoms . The median duration of diarrhoea was 5 days (range 1-35), that of other symptoms 4 days (range 1-30) . Those reporting articular symptoms were examined (51 patients) or contacted by telephone (13 patients) . Twelve percent (22/191) fulfilled the criteria for reactive arthritis (ReA) . The difference in the incidence of ReA between children and adults was not significant (8%, vs . 12%) . The median onset of joint symptoms was 8.5 days; symptoms were oligoarticular in 14 (67%) and polyarticular in four (19%) patients . Mostly ReA was mild, but in four patients (18%) the joint symptoms lasted for more than 4 months . Ten (45%) ReA patients had HLA-B27 tissue type . The duration and severity of ReA did not differ between HLA-B27 positive and negative patients . Fourteen (64%) ReA patients had received fluoroquinolone treatment before reactive joint or tendon symptoms manifested, but this treatment did not prevent ReA symptoms.

Microb Pathog, 1998 Oct, 25(4), 165 - 73
Genetic analysis of Shigella sonnei form I antigen: identification of a novel IS630 as an essential element for the form I antigen expression; Houng HS et al.; The form I coding region of Shigella sonnei was cloned and shown to have an operon-like rfb organization . It was found that the 11.0 kb HindIII-XbaI fragment of pHH201 encoding the form I antigen contains 10 contiguous open reading frames (ORF), ORF1 to ORF10 . Deletions from either end of pHH201, within ORF1 or ORF10, eliminated form I expression . ORF1 and ORF2 share significant nucleic and amino acids homologies to two ORF's of the Salmonella typhi Vi antigen genes . ORF5 in pHH201 is identical to IS630 . pHH2064, derived from pHH201, lacks the IS630 element and can stably express the form I antigen inE . coli HB101 . However, pHH2064 is structurally unstable in a S . sonnei form II host . This indicates that the presence of the IS630 gene within the S . sonnei rfb operon may be necessary for the stability of form I expression in S . sonnei . This finding is substantiated by the observation that all virulent S . sonnei isolates examined in this study retained the IS630 element within their rfb operon .

Scand J Infect Dis, 1998, 30(4), 355 - 7
Treatment with ciprofloxacin in children with typhoid fever; Thomsen LL et al.; We investigated the use, treatment results and safety of ciprofloxacin in the treatment of childhood typhoid and paratyphoid infections in an industrialized country . The study was retrospective, and the material consisted of children admitted to Hvidovre or Glostrup University Hospitals from 1991 to 1995, and treated with ciprofloxacin for a culture proven diagnosis of typhoid fever . 21 children were included, 18 had positive cultures for Salmonella typhi and 3 had positive cultures for S . paratyphi A . All isolates were fully susceptible to ciprofloxacin . The median duration of treatment was 10 d, median oral dose was 24 mg/kg/d and the median intravenous dose was 15 mg/kg/d . Within 4 d after start of treatment all subjects had a normal body temperature . No subjects had clinical or microbiological relapse and all stool cultures after end of treatment were negative . Adverse events were rare, but in 2 children a transient limb/ataxia or a period of confusion were recorded . Both children recovered within a few days without sequelae . We conclude that ciprofloxacin was effective and well tolerated for treatment of typhoid fever in children . The few adverse events that were recorded left no permanent sequelae, and were likely to be caused by the disease itself.

J Travel Med, 1997 Mar 1, 4(1), 32 - 37
Typhim Vitrade mark Vaccine; Fanning WL; Long before the term "Typhoid Mary" entered the vernacular in the early 1900s, investigators such as Huxham1 in 1782 and Schoenlein2 in 1839 had already differentiated typhoid fever-the typhus-like fever caused by Salmonella typhi-from other prolonged febrile syndromes such as rickettsial typhus fever.3 The notorious Mary Mallon had been identified as a carrier of the typhoid fever bacillus in 1907; by the time she was captured 8 years later, she had infected at least 50 people (causing the death of three) while working as a New York City cook under several assumed names.4 Even though the incidence of this serious infection has obviously decreased since 1900 in developed countries, it continues to be prevalent in developing countries . Consequently, most cases reported in the United States occur in international travelers . Prevention is critical because typhoid fever is associated with a high rate of complications, its course can be severe and prolonged, and multidrug-resistant strains have recently emerged.5

J Travel Med, 1995 Sep 1, 2(3), 165 - 168
Clinical Importance of Salmonella Paratyphi A Infection to Enteric Fever in Nepal; Shlim DR et al.; Background: Enteric fever in Nepal is caused by infection with Salmonella typhi or Salmonella paratyphi A . The clinical presentation of these two illnesses has never been compared in a population of travelers and expatriates . If the illnesses are clinically comparable, and if S . paratyphi A infection is sufficiently common, the choice of typhoid vaccine for Nepal may have to take into account the vaccine's efficacy in preventing infection with S . paratyphi A . Methods: NonNepalese patients presenting to the CIWEC Clinic with a history of 3 days of fever or greater were considered eligible for the study . Patients with positive blood or stool cultures for S . typhi or S . paratyphi A were entered into the study (along with three patients who had positive Widal titers only) . A questionnaire was administered by a physician to determine signs and symptoms . Treatment with oral chloramphenicol was openly compared to treatment with oral ciprofloxacin . Results: Forty-five cases of enteric fever were diagnosed during the 2 years of the study . Infection with S . typhi accounted for 20 cases, and S . paratyphi A was isolated in 22 cases . The illnesses were clinically indistinguishable . Treatment with chloramphenicol and ciprofloxacin was clinically comparable . Conclusions: Infection with S . paratyphi A accounts for a significant percentage of enteric fever presentations among tourists in Nepal, and the illness is comparable to infection with S . typhi . Therefore, the choice of typhoid vaccine for long-term travelers or expatriates in Nepal should take into account the vaccine's potential ability to also prevent S . paratyphi A infection . The only typhoid vaccine that can currently offer this type of cross protection is the whole-cell killed preparation.

Environ Mol Mutagen, 1998, 32(3), 269 - 80
1,4-Dioxane is not mutagenic in five in vitro assays and mouse peripheral blood micronucleus assay, but is in mouse liver micronucleus assay; Morita T et al.; 1,4-Dioxane, an animal carcinogen, was not previously genotoxic in in vitro assays . We reevaluated the compound's genotoxic potential in five in vitro genotoxicity tests in the presence and absence of S9 mix using recommended new protocols . We used the bacterial reverse mutation assay with Salmonella TA and E . coli WP2 strains, including the plate and preincubation methods, the CHO chromosomal aberration assay, including examination of polyploid induction and extended sampling time, the CHO sister-chromatid exchange assay with short and long treatment time, the mouse lymphoma tk assay (microtiter method), including longer treatment time (24 hr), and the CHO micronucleus assay with short and long treatment times . The highest concentration we used was five mg/ml or plate . We also evaluated the genotoxic effect of 1,4-dioxane in vivo by conducting peripheral blood and liver micronucleus assays in the same mice after single oral administration of up to 3,000 mg/kg . All in vitro assays and the peripheral blood micronucleus assay were negative . The mouse liver micronucleus assay, on the other hand, was positive, indicating that 1,4-dioxane might be genotoxic . It is also conceivable that the positive result in mouse liver micronucleus assay was due to a nongenotoxic mechanism, i.e., errors in genetic repair following enhancement of hepatocyte proliferation.

Zhonghua Liu Xing Bing Xue Za Zhi, 1997 Feb, 18(1), 26 - 9
{Efficacy and side effects following immunization with Salmonella typhi Vi capsular polysaccharide vaccine}; Wang ZG et al.; Efficacy and side effects following the immunization with Salmonella typhi Vi capsular polysaccharide vaccine (Vi) were assessed . The diluted solution (DS) of Vi was used as placebo . A total number of 777 children and adults were observed for side effect response . Mild and moderate fever appeared 16.93% and 0.05% in Vi group, 15.01% and 0.03% in DS group, respectively (statistically significant) . Two cases with mild local reaction were observed in Vi group . A total number of 81,506 vaccinees were investigated on the efficacy of Vi vaccine, using positive blood culture of Salmonolla typhi as a diagnostic criterion . The protective rate and index of vaccine were 71.35% and 3.49% respectively . If 2 cases of positive Widal's test were included in, the protective rate would come up to 78.17% with a protective index 4.85 . Clinical data showed that fever seen in the cases in Vi group was much lower than that of DS group . The systematic and local reaction of Vi vaccine were mild . The vaccine is safe and has high protective rate . It can also decrease the degree of fever with only one single dose as primary immunization . We believe Vi vaccine may serve as a vaccine of new generation to be promoted.

Lett Appl Microbiol, 1998 Oct, 27(4), 216 - 8
Phage types of Australian isolates of Salmonella enterica subsp . enterica serovar Virchow; Sullivan AM et al.; Australian isolates (79) of Salmonella enterica subsp . enterica serovar Virchow (Salmonella Virchow) were characterized by phage typing . Thirteen phage types were identified, of which phage type (PT) 8, representing 54 of 79 isolates, was predominant, as it had been in England and Wales up to 1994 when it was replaced by PT26 . Other phage types identified in Australia were distinct from those observed in England and Wales . This suggests that PT8 may be a global phage type, while others may be distinct to particular geographical regions.

Lett Appl Microbiol, 1998 Oct, 27(4), 207 - 10
Antimicrobial activity of Pelargonium essential oils added to a quiche filling as a model food system; Lis-Balchin M et al.; Eight essential oils obtained by steam distillation from the scented leaves of Pelargonium species and cultivars were added at 250, 500 and 1000 ppm to a quiche filling, inoculated with either Saccharomyces ludwigii or Zygosaccharomyces bailii (at 10(8) cfu g-1), Salmonella enteriditis or Listeria innocua (at 10(9) cfu g-1) . The quiche fillings were then kept at 25 degrees C for 24 h and the residual number of micro-organisms determined using the pour plate technique . There was an effective antimicrobial activity by the Pelargonium essential oils at 250 ppm, comparable with that of commercial thyme oil, an excellent antimicrobial agent, against Saccharomyces ludwigii and Zygosaccharomyces bailii, and a lesser inhibition compared with commercial thyme against Salm, enteriditis . There was a greater diversity of activity against L . innocua, which was in some cases more effective than commercial thyme oil . At 500 ppm, there was a greatly increased inhibition of microbial growth using the Pelargonium essential oils, which was comparable with that of commercial thyme, clove, geranium and coriander oils . As there is no evidence for the toxicity of any of these novel Pelargonium oils, and their odour does not make the delicately flavoured quiche filling unpalatable, there is a strong potential for their use in food processing.

J Appl Microbiol, 1998 Oct, 85(4), 693 - 702
Application of random amplified polymorphic DNA analysis to differentiate strains of Salmonella typhi and other Salmonella species; Shangkuan YH et al.; A Random Amplified Polymorphic DNA (RAPD) fingerprinting method was developed to differentiate isolates of Salmonella serotype typhi (S . typhi) and other Salmonella isolates . A panel of five primers was used to examine 63 isolates of Salm . typhi, including 56 strains isolated in Taiwan and seven strains obtained abroad . Twenty-one RAPD types were revealed using the RAPD fingerprinting method . An RAPD with primer 6032 yielded a polymorphism in a 350 bp fragment that differentiated the attenuated vaccine strain Salm . typhi Ty21a from the rest of the Salm . typhi strains . Strains of Salm . typhi were divided into five types with primer D14307 . Primer D14307 also proved capable of discrimination among 65 other Salmonella isolates representing 42 different serotypes . The bacterial DNA used in this RAPD protocol was obtained using a commercially available DNA extraction kit (GeneReleaser) . The DNA of various strains of Salmonella from this simple extraction procedure could be discriminated within a few hours using the RAPD technique.

Zentralbl Bakteriol, 1995 Oct, 282(4), 474 - 97
Pattern analysis of human Salmonella enteritidis infection; Bogel K et al.; Information on salmonella serovar, community, and date of isolation concerning 10,368 cases of S . enteritidis (SE) infection and 1163 cases of S . typhimurium (ST) infection reported in 1992 to the Salmonella Data Bank of the Land of Brandenburg have been analyzed for clusters and trends on case/time diagrams . A breakdown by district provided a suitable degree of "resolution" for discrimination of "Episodes of Increased Case Frequency" (EICF) and 7 days moving averages . Thus 39 of the 44 districts of the Land were included in the evaluation of SE cases . The population size of the remaining 5 districts was too high for clear episode discrimination . EICFs were subdivided into (a) 16 outbreaks (another 10 outbreaks occurred outside EICFs), which had also been identified and officially reported by local health services as a result of compulsory investigation of cases and their social environment, and (b) 44 "case accumulations" (ACCs), which were only identified by retrospective analysis of the case/time diagrams . By this procedure, three case categories of distinct properties have been found for SE transmission from the animal reservoir to the human population: outbreaks, ACCs, and "truly sporadic cases" scattered over the district outside outbreaks and ACCs (Table 3) . Truly sporadic cases (Table 6) represented the largest proportion of SE cases . ACCs accounted for 37% and outbreaks, for 12% . The most striking result concerns the ACCs, which cover slightly larger geographical areas (mean: 3.5 communities) and last longer (mean: 3 weeks, but up to 7 weeks) than officially recorded outbreaks (means: 2 communities and 2 weeks) . SE-ACCs differed from SE outbreaks also in the seasonal pattern . Otherwise, ACCs met outbreak characteristics including the average number of persons involved (mean: 64, for outbreaks: 42; Table 4) . The results suggest that SE-ACCs represent an important and distinct element in the SE epidemic . This conclusion is supported by a comparison of the findings with results obtained by the same procedure for ST cases . ST outbreaks do not differ from ST-ACCs in any respect, and both types of ST-episodes are of significantly shorter duration and comprise less people than episodes due to SE . The public health significance of the SE-ACCs as a newly detected and particular element of the current SE epidemic is discussed . In view of the epidemiological significance, i.e . the high proportion of all SE cases involved, it appears justified to develop methods for the early detection of ACCs and the search for the "missing link" between the cases and their source at the community level.

Sci Total Environ, 1998 Sep 29, 221(1), 31 - 42
Statistical procedures for estimating the detection limit and determination limit of the Ames Salmonella mutagenicity assay; Takanashi H et al.; Novel and flexible procedures for estimating the detection limit as well as the determination limit of the Ames mutagenicity assay were proposed to evaluate the genetoxicity of a water sample . The accumulated data under the test conditions of TA 100-S9 by our group were taken as examples and analyzed to estimate the detection limit and the determination limit . The detection limit was estimated at 1.7 as the MR value when duplicate plates were used in the negative control test . However, it decreased to 1.4 as the MR level when quadruple plates were used in the negative control test . Therefore it was found that the sensitivity of the Ames mutagenicity assay was improved very easily by increasing the number of plates for the negative control test from two to four . The application of the conventional twofold rule to the data obtained with the strain TA100 was considered too conservative . The determination limit was regarded at 2.2 as the MR value under the following conditions: (a) quadruple plates were used in the negative control test; (b) three dose-steps including negative control step were designed at regular intervals; and (c) duplicate plates were used for each dose-step . It was proved by comparing data of two students that the detection limit and the determination limit estimated in this study were considered acceptable to any well trained students.

JAMA, 1998 Nov 4, 280(17), 1504 - 9
Outbreak of Salmonella serotype Hartford infections associated with unpasteurized orange juice; Cook KA et al.; CONTEXT: Acidic foods such as orange juice have been thought to be unlikely vehicles of foodborne illness . OBJECTIVE: To investigate an outbreak of Salmonella enterica serotype Hartford (Salmonella Hartford) infections among persons visiting a theme park in Orlando, Fla, in 1995 . DESIGN: Review of surveillance data, matched case-control study, laboratory investigation, and environmental studies . SETTING: General community . PARTICIPANTS: The surveillance case definition was Salmonella Hartford or Salmonella serogroup C1 infection in a resident of or a visitor to Orlando in May or June 1995 . In the case-control study, case patients were limited to theme park hotel visitors and controls were matched to case patients by age group and hotel check-in date . MAIN OUTCOME MEASURES: Risk factors for infection and source of implicated food . RESULTS: Sixty-two case patients from 21 states were identified . Both Salmonella Hartford and Salmonella enterica serotype Gaminara (Salmonella Gaminara) were isolated from stool samples of 1 ill person . Thirty-two case patients and 83 controls were enrolled in the case-control study . Ninety-seven percent of case patients had drunk orange juice in the theme park vs 54% of controls (matched odds ratio, undefined; 95% confidence interval, 5.2 to undefined) . The orange juice was unpasteurized and locally produced . Salmonella Gaminara was isolated from 10 of 12 containers of orange juice produced during May and July, indicating ongoing contamination of juice probably because of inadequately sanitized processing equipment . CONCLUSIONS: Unpasteurized orange juice caused an outbreak of salmonellosis in a large Florida theme park . All orange juice was recalled and the processing plant closed . Pasteurization or other equally effective risk-management strategies should be used in the production of all juices.

Nat Med, 1998 Nov, 4(11), 1247 - 52
Regulation of host immune responses by modification of Salmonella virulence genes; VanCott JL et al.; Modifying bacterial virulence genes to probe the nature of host immunity is mostly unexplored . Here we investigate whether host immune responses can be regulated by modification of bacterial virulence genes . In mice, attenuated Salmonella mutant strains with clinical relevance elicited differential host immune responses . Oral administration of a mutant strain with a PhoP-null phenotype promoted potent innate immune responses of macrophages that were sufficient for host defense . In contrast, administration of an Aro- mutant strain elicited stronger specific antibody and T-helper (Th)-cell responses, wherein Th1-type cells were required for clearance . Thus, genetic manipulation of bacteria may be used to broadly alter immune mechanisms that regulate attenuation within the host and to tailor host immunity to specific bacterial pathogens.

Zentralbl Bakteriol, 1998 Oct, 288(2), 181 - 93
Inter- and intra-phage type differentiation of Salmonella enterica subsp . enterica serovar enteritidis isolates using molecular typing methods; Weide-Botjes M et al.; Seventy-six Salmonella enterica subsp . enterica serovar Enteritidis (S . Enteritidis) isolates which represented 14 phage types and RDNC isolates were investigated by several independent molecular methods . Eleven different plasmid profiles were detected . Plasmid-encoded virulence genes of the spv gene cluster were shown by hybridization with a spvB/C gene probe to be located on plasmids of either 55 kbp or 95 kbp . Ribotyping as performed with gene probes that recognized either the entire rrn operon or 16S rRNA genes allowed no differentiation between the S . Enteritidis isolates . Three different hybridization patterns could be observed by IS200-typing . Macrorestriction analysis of XbaI-, SpeI- and NotI-digested whole cell DNA proved to be the most discriminatory method as confirmed by the calculation of discriminatory indices . Based on the data obtained from plasmid analysis and macrorestriction analyses with three suitable restriction endonucleases, the 76 S . Enteritidis isolates were assigned to 26 different genomic groups . The observation that several genomic groups included isolates of different phage types has suggested that a combination of suitable molecular methods and phage typing is most useful for tracing S . Enteritidis isolates in epidemiological investigations.

FEMS Microbiol Lett, 1998 Oct 15, 167(2), 263 - 9
Molecular characterization of Salmonella enterica subsp . enterica serovar Typhimurium DT009 isolates: differentiation of the live vaccine strain Zoosaloral from field isolates; Frech G et al.; A total of 25 epidemiologically unrelated Salmonella enterica subsp . enterica (S.) serovar Typhimurium DT009 isolates from various human and animal sources, the original S . Typhimurium DT009 Zoosaloral live vaccine strain and two Zoosaloral strains reisolated from vaccinated chickens were investigated by various molecular typing methods (I) to determine the most suitable method or combination of methods for the differentiation of DT009 field isolates and (II) to investigate which molecular methods are suitable to differentiate the Zoosaloral live vaccine strain from field isolates of the same phage type . Based on the results of plasmid profile analysis, IS200 typing and macrorestriction analysis with XbaI, SpeI and BlnI, the 28 S . Typhimurium DT009 isolates were assigned to 16 different genomic groups, one of which was exclusively represented by the original and the reisolated Zoosaloral strains . IS200 typing was the most discriminatory single method for the differentiation of the DT009 isolates followed by plasmid profile analysis and BlnI-macrorestriction analysis . The Zoosaloral vaccine strain differed from the DT009 field isolates by its unique HindIII-fragment pattern of the virulence plasmid and by its unique SpeI-macrorestriction pattern.

FEMS Microbiol Lett, 1998 Oct 15, 167(2), 245 - 53
The variant rpoS allele of S . enteritidis strain 27655R does not affect virulence in a chick model nor constitutive curliation but does generate a cold-sensitive phenotype; Allen-Vercoe E et al.; Adherence of pathogenic Escherichia coli and Salmonella spp . to host cells is in part mediated by curli fimbriae which, along with other virulence determinants, are positively regulated by RpoS . Interested in the role and regulation of curli (SEF17) fimbriae of Salmonella enteritidis in poultry infection, we tested the virulence of naturally occurring S . enteritidis PT4 strains 27655R and 27655S which displayed constitutive and null expression of curli (SEF17) fimbriae, respectively, in a chick invasion assay and analysed their rpoS alleles . Both strains were shown to be equally invasive and as invasive as a wild-type phage type 4 strain and an isogenic derivative defective for the elaboration of curli . We showed that the rpoS allele of 27655S was intact even though this strain was non-curliated and we confirmed that a S . enteritidis rpoS::strr null mutant was unable to express curli, as anticipated . Strain 27655R, constitutively curliated, possessed a frameshift mutation at position 697 of the rpoS coding sequence which resulted in a truncated product and remained curliated even when transduced to rpoS::strr . Additionally, rpoS mutants are known to be cold-sensitive, a phenotype confirmed for strain 27655R . Collectively, these data indicated that curliation was not a significant factor for pathogenesis of S . enteritidis in this model and that curliation of strains 27655R and 27655S was independent of RpoS . Significantly, strain 27655R possessed a defective rpoS allele and remained virulent . Here was evidence that supported the concept that different naturally occurring rpoS alleles may generate varying virulence phenotypic traits.

Carcinogenesis, 1998 Oct, 19(10), 1795 - 801
Mint prevents shamma-induced carcinogenesis in hamster cheek pouch; Samman MA et al.; Shamma, a complex mixture of powdered tobacco, slaked lime, ash, oils, spices and other additives, has been linked to oral cancer in Saudi Arabia . Shamma varies in colour and odour due to the nature of the additives which characterize different brands . Using the Ames Salmonella assay, a chloroform extract of a brand named 'white shamma' (WSH) was found to be mutagenic, while that of a brand called 'brown shamma' (BSH), which is known to contain mint as a flavouring agent, was found to be non-mutagenic . Using HPLC, a mutagenic and a non-mutagenic fraction were isolated from the extract of BSH . The non-mutagenic fraction of BSH was found to neutralize the genotoxic effect of the mutagenic fraction when the two were recombined . A chloroform extract of mint showing no mutagenic activity in the Ames assay effectively inhibited the mutagenicity of carcinogens/mutagens like benzo{a}-pyrene, aflatoxin B1, methylmethane sulfonate and extract of WSH . A carcinogenicity assay designed to test the effects of WSH and BSH in the hamster cheek pouch model showed that the former was tumorigenic, while the latter was not . However, when crushed leaves of mint were mixed with powdered WSH (in 1:1 proportion), the tumorigenic effect of the latter was abolished . These data strongly suggested that mint has a chemopreventive effect against shamma-induced carcinogenesis, which could be due to its antimutagenic properties.

Mutat Res, 1998 Nov 9, 419(1-3), 53 - 68
Effect of Salmonella assay negative and positive carcinogens on intrachromosomal recombination in S-phase arrested yeast cells; Galli A et al.; A wide variety of carcinogens including Ames assay (Salmonella) positive as well as Salmonella negative carcinogens induce intrachromosomal recombination (DEL recombination) in Saccharomyces cerevisiae . We have shown previously that the Salmonella positive carcinogens, ethyl methanesulfonate (EMS), methyl methanesulfonate (MMS) and 4-Nitroquinoline-N-oxide (4-NQO, and the Salmonella negative carcinogens, safrole, benzene, thiourea, carbon tetrachloride, and urethane, induced DEL recombination in growing, in G1 and in G2 arrested yeast cells . Since we found interesting differences in response between dividing and arrested cells, we wanted to find out whether these differences were due to the difference between cell division versus cell cycle arrest or to any particular cell cycle phase . In the present paper we incubated cells in the presence of hydroxyurea (HU) for cell cycle arrest in S-phase and exposed them to the above carcinogens, and plated them onto selective medium to determine DEL and interchromosomal recombination (ICR) frequencies . It was surprising that carbon tetrachloride had no effect on DEL recombination or ICR in HU treated cells even though it induced DEL recombination in G1 and G2 arrested as well as dividing cells . Further experiments are in agreement with the interpretation that carbon tetrachloride was responsible for prematurely pushing G1 cells into S-phase . The consequence of this may be replication on a damaged template which may be responsible for the action of carbon tetrachloride . EMS, MMS, 4-NQO and urethane were more recombinagenic in HU treated cells than in previous experiments with G2 arrested cells . None of the carcinogens appeared to be activated by S9 for either DEL recombination or ICR induction . Furthermore, we only detect cytochrome P-450 in dividing but not in arrested cells, arguing that possible differences in the ability to metabolize the compounds does not explain the observed differences for DEL recombination induction in the different cell cycle phases . We discuss these data in terms of the mechanism of induced DEL recombination and the possible biological activities of these carcinogens .

East Afr Med J, 1998 Jul, 75(7), 396 - 401
Bacterial meningitis in a rural Kenyan hospital; Honnas A et al.; In a prospective study to investigate mortality and antibiotic resistance in meningitis patients, thirty two meningitis cases were seen over a three month period . Mean age was 11.3 years (range one month-60 years) . Cerebrospinal fluid cultures were positive in 26 patients (81.3%) . S.pneumoniae was responsible for 15 cases (46.9%), followed by H.influenzae in seven (21.9%) . Salmonella infection was seen in two patients, and E.coli and N.meningitidis in one each . Twelve patients (37.5%) died during hospitalisation with most of the deaths occurring within 48 hours after admission . No patients presented with atypical signs of meningitis . No significant differences were found between delay and outcome . Malaria parasites were found in blood of thirteen patients (41%), but did not contribute to higher mortality . Three of H.influenzae isolates (42.9%) were resistant to ampicillin and penicillin . Reduced sensitivity to penicillin was found in two (13.3%) of S.pneumoniae isolates.

Psychoneuroendocrinology, 1998 Jul, 23(5), 427 - 37
Endotoxin-induced changes in sleep and sleepiness during the day; Hermann DM et al.; Sleepiness is a common symptom of infectious diseases . However, the peculiarities and causes of impaired vigilance during host defense activation are largely unknown . It has been shown earlier that mild host defense activation by endotoxin does not affect daytime sleepiness and non-rapid eye movement (NREM) sleep in humans . In the present study we investigated the effects of a more intensive stimulation of the host defense by Salmonella abortus equi endotoxin (0.8 ng/kg), administered 12 h following host response priming by granulocyte colony-stimulating factor (300 micrograms s.c.), on daytime sleep and sleepiness in a placebo-controlled design in ten healthy men . Six equidistant polysomnographically monitored naps were scheduled across the day and the time course of subjective sleepiness was assessed . Endotoxin induced prominent increases in rectal temperature, and in the plasma levels of tumor necrosis factor-alpha, interleukin-6, interleukin-1 receptor antagonist, and cortisol . In the first nap, 1 h following endotoxin administration, total sleep time and NREM sleep stage 2 were reduced, whereas wakefulness and sleep onset latency were increased . Following this nap sleepiness transiently increased peaking prior to the second nap . However, this nap and the following ones were not influenced by endotoxin . These results suggest that prominent host defense activation reduces daytime NREM sleep and increases sleepiness . One cause of daytime sleepiness during infections may be prior sleep disruption and this kind of sleepiness may not necessarily be associated with an increased sleep pressure.

J Food Prot, 1998 Oct, 61(10), 1405 - 7
Cheese-associated outbreaks of human illness in the United States, 1973 to 1992: sanitary manufacturing practices protect consumers; Altekruse SF et al.; To identify contributing factors for cheese-associated outbreaks, we reviewed all cheese-associated outbreaks of human illness reported to the Centers for Disease Control and Prevention (CDC) with onsets during 1973 to 1992 . The infrequency of large, cheese-associated outbreaks was notable because such outbreaks had been a frequent public health problem before the mid-20th century . Of 32 reported cheese-associated outbreaks, 11 attributed to manufacturing errors caused most of the illnesses and hospitalizations and all 58 deaths . Important factors in these 11 outbreaks were manufacturing cheese with raw or improperly pasteurized milk and postpasteurization contamination . If current Food and Drug Administration sanitary requirements for cheesemaking had been met, these outbreaks would have been preventable . In two outbreaks of Salmonella infections, fewer than 10 Salmonella per 100 g of cheese were detected . In two outbreaks of Brucella infections, efforts to recover the pathogen from the implicated cheese were unsuccessful, emphasizing the inadequacy of end product testing for assuring consumer safety . Curing cheeses kills most bacteria present in cheeses; however, evidence from sources other than the CDC Foodborne Disease Outbreak Surveillance System suggests that curing alone may not be a sufficient pathogen control step to eliminate Salmonella, Listeria, and E . coli O157:H7 from cheese.

J Food Prot, 1998 Oct, 61(10), 1381 - 3
Confirmation of presumptive Salmonella colonies by the polymerase chain reaction; Stefanovicova A et al.; The potential of a genus-specific polymerase chain reaction (PCR) for the confirmation of Salmonella colonies was evaluated on 209 presumptive Salmonella colonies obtained by the standard method ISO 6579 . The PCR method employing primers ST11 and ST15 (S . Aabo et al., Mol . Cell . Probes 7:171-178, 1993) gave results identical (100%) to those of the biochemical and serological identification, in terms of discrimination of Salmonella from non-Salmonella strains . PCR could be used directly on the colonies from selective plating media, which allowed a reduction of the time required for confirmation to a maximum of 6 h.

J Food Prot, 1998 Oct, 61(10), 1305 - 11
Efficacy of spray application of chlorinated water in killing pathogenic bacteria on raw apples, tomatoes, and lettuce; Beuchat LR et al.; Washing whole and cut produce by dipping or submerging in chlorinated water has a sanitizing effect, although reduction in microbial populations is minimal and is usually less than 100-fold . A study was undertaken to evaluate the efficacy of a spray application of chlorine in killing Salmonella, Escherichia coli O157:H7, Listeria monocytogenes, yeasts and molds, and total aerobic mesophilic microorganisms on whole apples, tomatoes, and lettuce leaves . Inoculated produce was treated (sprayed and then soaked) with water (control) or solutions containing 200 or 2,000 ppm of chlorine for 0, 1, 3, 5, or 10 min, rinsed with sterile water, and analyzed for populations (CFU/cm2) of target microorganisms . Compared to the control treatment, further reductions in numbers of pathogens of 0.35 to 2.30 log CFU/cm2 were achieved by treatment with chlorine . Chlorine was generally more effective at 2,000 ppm than at 200 ppm . Inactivation of microorganisms occurred essentially within 1 min after application of chlorine . These reductions are significant relative to populations of pathogenic microorganisms that may be present on produce . Spray application of chlorine to raw produce at food service or household levels may be a suitable, and more convenient, alternative to treatment by dipping or submersion.

Gastroenterology, 1998 Nov, 115(5), 1272 - 7
Antibiotic resistance in Helicobacter pylori: implications for therapy; Graham DY; Helicobacter pylori is a conventional gram-negative bacteria that causes an infection of the gastric mucosa . The organism is sensitive to most common antibiotics and theoretically should be easy to eradicate, provided that the patient takes antibiotics to which the organism is sensitive using a sufficient dose and duration of therapy . Unfortunately, the infection has proved difficult to cure . There are many other examples of bacterial infections that resist treatment with antibiotics even when the individual organisms demonstrate antibiotic sensitivity in vitro (e.g., Salmonella in the biliary tract) . Failure can be due to the presence of antibiotic-resistant organisms, features of the infection may make it inaccessible to the antibiotics despite having antibiotic-sensitive organisms (a resistant infection), or both . Acquired resistance of H . pylori to clarithromycin, metronidazole, tetracycline, and amoxicillin have all been described.

Appl Environ Microbiol, 1998 Nov, 64(11), 4623 - 6
Response of Salmonella choleraesuis LT2 spheroplasts and permeabilized cells to the bacteriocin AS-48; Abriouel H et al.; The bacteriocin AS-48 was not active against intact cells of Salmonella choleraesuis LT2 at neutral pH, but it was very effective on spheroplasts, suggesting that the outer membrane (OM) acts as a protective barrier . Cells sublethally injured by heat or treated with OM-permeabilizing agents (i.e., EDTA and Tris) became sensitive to AS-48 . The combination of two or more treatments decreased the amount of AS-48 required for cell killing . The activity of AS-48 against heat-injured cells did not change significantly in the pH range of 4.0 to 8.0 . AS-48 showed bactericidal activity against intact cells of Salmonella at pH 4.0 . The potency of AS-48 increased greatly when the bacteriocin was dissolved at pH 9.0.

Eur J Clin Microbiol Infect Dis, 1998 Aug, 17(8), 551 - 5
Multiple analysis of a foodborne outbreak caused by infant formula contaminated by an atypical Salmonella virchow strain; Usera MA et al.; An outbreak of food poisoning involving most autonomous Spanish communities was detected in the first half of 1994 . The causative food was infant formula milk contaminated by lactose-fermenting Salmonella virchow . It was not possible to isolate the causative strain from the manufacturer's facilities . During the same period of time, there was a significant increase in lactose-non-fermenting Salmonella virchow strains compared with the same period in previous years . Simultaneously, lactose-non-fermenting strains were recovered from clinical samples from children and from some milk samples that were involved in the outbreak . Therefore, it was speculated that the outbreak might be more extensive than initially thought . The following epidemiological markers were used for typing the Salmonella virchow strains involved in the outbreak: (i) phage typing: (ii) ribotyping, using a set of 20 different endonucleases: and (iii) pulsed-field gel electrophoresis, using three different endonucleases . The most useful markers for this serotype were phage typing and pulsed-field gel electrophoresis, since ribotyping was not able to distinguish all strains tested . The results obtained revealed that the outbreak was caused by at least two strains: one presenting phage type 4-4a and pulsed-field patterns A1 or A2 and L+ or L-, and another presenting phage type 2 and pulsed-field patterns A1 or A2 and L+ or L- . The results indicate that the outbreak was more extensive than initially thought and that the Virchow serotype is very clonal in Spain.

Vaccine, 1998 Dec, 16(20), 1993 - 9
Enhanced immunogenicity of a recombinant genital warts vaccine adjuvanted with monophosphoryl lipid A; Thompson HS et al.; The regression of genital warts is believed to be a T-cell-mediated immune effect . We have sought to enhance the immunogenicity of a therapeutic vaccine for the treatment of genital warts with the use of the adjuvant monophosphoryl lipid A (MPL-immunostimulant), a detoxified form of the lipopolysaccharide (LPS) of Salmonella minnesota R595 . The comparative immunogenicity and reactogenicity of a recombinant human papillomavirus type 6 (HPV6) L2E7 fusion protein in either aqueous, oil-in-water emulsions or Alhydrogel formulations containing MPL was evaluated . We conclude that the simple addition of MPL to the L2E7 fusion protein already adsorbed onto Alhydrogel preferentially enhances antigen specific in vitro T-cell proliferative responses, IFN gamma production and in vivo delayed type hypersensitivity responses without increasing its reactogenicity.

Res Microbiol, 1998 Sep, 149(8), 601 - 4
Supplement 1997 (no . 41) to the Kauffmann-White scheme; Popoff MY et al.; This supplement reports the characterization of 15 new Salmonella serovars recognized in 1997 by the WHO Collaborating Centre for Reference and Research on Salmonella: 8 were assigned to S . enterica subsp . enterica, 4 to subspecies salamae, 2 to subspecies diarizonae, and 1 to subsp . houtenae . In addition, the antigenic factors H:z85 and H:z87 are described and one modification to the Kauffmann-White scheme is reported.

Protein Sci, 1998 Oct, 7(10), 2223 - 32
Phage P22 tailspike protein: removal of head-binding domain unmasks effects of folding mutations on native-state thermal stability; Miller S et al.; A shortened, recombinant protein comprising residues 109-666 of the tailspike endorhamnosidase of Salmonella phage P22 was purified from Escherichia coli and crystallized . Like the full-length tailspike, the protein lacking the amino-terminal head-binding domain is an SDS-resistant, thermostable trimer . Its fluorescence and circular dichroism spectra indicate native structure . Oligosaccharide binding and endoglycosidase activities of both proteins are identical . A number of tailspike folding mutants have been obtained previously in a genetic approach to protein folding . Two temperature-sensitive-folding (tsf) mutations and the four known global second-site suppressor (su) mutations were introduced into the shortened protein and found to reduce or increase folding yields at high temperature . The mutational effects on folding yields and subunit folding kinetics parallel those observed with the full-length protein . They mirror the in vivo phenotypes and are consistent with the substitutions altering the stability of thermolabile folding intermediates . Because full-length and shortened tailspikes aggregate upon thermal denaturation, and their denaturant-induced unfolding displays hysteresis, kinetics of thermal unfolding were measured to assess the stability of the native proteins . Unfolding of the shortened wild-type protein in the presence of 2% SDS at 71 degrees C occurs at a rate of 9.2 x 10(-4) s(-1) . It reflects the second kinetic phase of unfolding of the full-length protein . All six mutations were found to affect the thermal stability of the native protein . Both tsf mutations accelerate thermal unfolding about 10-fold . Two of the su mutations retard thermal unfolding up to 5-fold, while the remaining two mutations accelerate unfolding up to 5-fold . The mutational effects can be rationalized on the background of the recently determined crystal structure of the protein.

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