Salmonella

Mutat Res, 1999 Sep 15, 445(1), 1 - 8
Comparative antimutagenic effects of D- and L-centchroman and their comparison with tamoxifen in Salmonella assay; Gupta S et al.; Centchroman (CC)--a contraceptive and a candidate drug for breast cancer has been developed by the Central Drug Research Institute . It has been successfully marketed as a contraceptive for last several years . CC has also been reported to exhibit partial to complete remission of lesions in 40.5% breast cancer patients . Recently, we have reported the antimutagenic effects of CC in Ames Salmonella assay and in vivo and in vitro mammalian cells in multiple mutational assay . The potent antimutagenic activity of CC and its anti-breast cancer activity prompted us to evaluate the antimutagenic effects of its enantiomers, i.e., D-centchroman (DC) and L-centchroman (LC) in the Ames Salmonella strains TA97a, TA98, TA100 and TA102 against known bacterial mutagens . Attempts have also been made to compare the results of antimutagenicity assays of CC and its enantiomers with the known breast cancer drug tamoxifen (TM) . The main objective was to identify the best suitable form of CC having antimutagenic effects with anticancer profile similar to TM, would replace the latter for toxicity reasons . When mutagenicity assays were carried out with these compounds as expected like CC, none of these enantiomers or TM showed any mutagenic effects in these Salmonella strains . In the antimutagenicity assay a significantly reduced number of bacterial histidine revertant colonies were observed when positive compounds were co-incubated with certain concentrations of LC compared with bacterial plates treated with respective positive compound . This was observed in some concentrations in all the four strains in both plate incorporation and preincubation tests . The protective effects of LC in preincubation tests were slightly more than in plate incorporation tests . Both the DC and TM showed protective effects only in certain concentrations in some strains in either plate or preincubation tests . Thus the above results indicate that LC showed more protective effects in Salmonella strains TA97a, TA98, TA100 and TA102 than either DC or TM.

Mutat Res, 1999 Aug 18, 444(2), 463 - 70
Genotoxicity assessment of new synthesized acridine derivative--3,6-diamino-10-methyl-9,10-dihydroacridine; Ferenc T et al.; A new synthesized acridine derivative, 3,6-diamino-10-methyl-9, 10-dihydroacridine (AcrH), was tested for in vitro reverse mutations with Salmonella TA strains, chromosome aberrations and sister chromatid exchanges (SCE) in human lymphocytes, and for in vivo chromosome aberrations in bone marrow of mice . Using the classic plate incorporation method, mutagenicity of AcrH in bacterial cells (TA97a, TA98, TA100 and TA102) was observed in the experiments performed with, and without, rat liver S9 metabolic activation . The reverse mutation assay showed no difference in mutagenic activity between AcrH and acriflavine (Acr(+)) in the test with TA97 . The results of in vitro chromosome aberrations assay revealed potential clastogenicity . The test using macroculture of human lymphocytes induced mainly chromatid gaps . The experiments with human lymphocytes revealed SCE-inducing effect of AcrH and Acr(+) . In an in vivo study, AcrH given intraperitoneally to Balb/c mice did not cause any significant increase in the percentage of cells with aberrations compared to the negative control.

Carbohydr Res, 1999 Jun 30, 319(1-4), 184 - 91
Chemoenzymatic synthesis of the Salmonella group E1 core trisaccharide using a recombinant beta-(1-->4)-mannosyltransferase; Zhao Y et al.; The chemical synthesis of the bacterial O-antigen from Salmonella serogroup E1, 3-O-(4-O-beta-D-mannopyranosyl-alpha-L-rhamnopyranosyl)-alpha-D-galactos e, presents a particular challenge because it contains a beta-(1-->4) mannosidic linkage to L-rhamnose . We report a chemoenzymatic synthesis of this crucial antigenic material which culminates in the enzymatic formation of the critical beta-mannosyl connection catalyzed by Salmonella GDP-alpha-D-Man:alpha Rha1-->3 alpha Gal-PP-Und beta-(1-->4)-mannosyltransferase (ManT beta 4) . In comparison with previous synthetic routes, this method is advantageous since it utilizes intermediates, available in significant yield, which can be readily derivatized from the reducing end to present flexibility for analog construction, while the enzymatic construction of the Man1-->4Rha glycosidic bond is both rapid and occurs in high yield . Furthermore, the reported spectroscopic and enzymatic structural characterization of the trisaccharide product furnishes the first indisputable functional link between wbaO and ManT beta 4 and clearly sets the stage for the future mechanistic study and exploitation of this fascinating glycocatalyst.

Vaccine, 1999 Oct 14, 18(5-6), 449 - 59
Safety and immunogenicity of phoP/phoQ-deleted Salmonella typhi expressing Helicobacter pylori urease in adult volunteers; DiPetrillo MD et al.; Salmonella typhi Ty800, deleted for the Salmonella phoP/phoQ virulence regulon has been shown to be a safe and immunogenic single dose oral typhoid fever vaccine in volunteers . This promising vaccine strain was modified to constitutively express a heterologous protein of Gram negative bacterial origin, Helicobacter pylori urease subunits A and B, yielding S . typhi strain Ty1033 . Seven volunteers received single oral doses of > or = 10(10) colony forming units of Ty1033; an eighth volunteer received two doses 3 months apart . Side effects were similar to those observed previously in volunteers who received the unmodified vector Ty800 . All volunteers had strong mucosal immune responses to vaccination as measured by increases in IgA-secreting cells in peripheral blood directed against S . typhi antigens . Seven of eight volunteers had convincing seroconversion as measured by increases in serum IgG directed against S . typhi flagella and lipopolysaccharide antigens by ELISA . No volunteer had detectable mucosal or humoral immune responses to the urease antigen after immunization with single doses of Ty1033 . A subset of three volunteers received an oral booster vaccination consisting of recombinant purified H . pylori urease A/B and E . coli heat labile toxin adjuvant 15 days after immunization with Ty1033 . None of three had detectable humoral or mucosal immune responses to urease . Expression of a stable immunogenic protein in an appropriately attenuated S . typhi vector did not engender detectable mucosal or systemic antibody responses; additional work will be needed to define variables important for immunogenicity of heterologous antigens carried by live S . typhi vectors in humans.

J R Soc Health, 1999 Sep, 119(3), 146 - 55
Canada goose (Branta canadensis) droppings as a potential source of pathogenic bacteria; Feare CJ et al.; Canada goose droppings, collected in parks to which the public had access, were screened for a range of bacteria that could be pathogenic in man . Droppings of Canada geese, and other waterfowl, did contain such bacteria, including some that are well-known causes of illness in man . These bacteria, plus a species of Salmonella that was experimentally inoculated into droppings, were shown to survive and multiply in the droppings for up to one month after their deposition by geese . Canada geese ranged further from water than other waterfowl species and thus distributed their droppings over a larger area of park grassland . This more widespread distribution of their droppings leads Canada geese to pose a greater potential health risk than other waterfowl studied here, but variations in human responses to challenge with bacteria, and variations in human and waterfowl behaviour in public parks, renders quantification of this risk impossible.

Microbiology, 1999 Sep, 145 ( Pt 9), 2443 - 51
Identification of O-antigen polymerase transcription and translation start signals and visualization of the protein in Salmonella enterica serovar Typhimurium; Wong DK et al.; The wzy/rfc gene, encoding the O-antigen polymerase, of Salmonella enterica serovar Typhimurium has been previously cloned and sequenced . In the present work, the wzy transcriptional startpoint was initially identified by primer extension . Next, wzy promoter strength in Escherichia coli K-12 was measured, and was found to be greater than that of the induced lac promoter . To define the Wzy translational startpoint, DNA including the wzy promoter and the putative first five residues of the Wzy protein was fused to the N-terminus of glutathione-S-transferase, and the fusion protein purified by affinity chromatography . N-terminal amino acid sequencing yielded the Wzy translational startpoint . Next, the Wzy protein was C-terminally tagged with the FLAG peptide, and immunoblotting of an S . typhimurium strain expressing a low-copy wzy-FLAG gene (five copies per cell) localized the intact Wzy protein in the cytoplasmic membrane of S . typhimurium cells . The Wzy protein was not well-expressed from a multi-copy wzy-FLAG+ plasmid in S . typhimurium, or in E . coli K-12.

Respiration, 1999, 66(5), 448 - 54
Effect of nitric oxide synthase inhibition on hemoglobin-oxygen affinity and lipid peroxidation in rabbits during fever; Zinchuk V; BACKGROUND: Nitric oxide (NO) is one of the most important biologic messengers and takes part in the development of fever . It can influence on the body prooxidant-antioxidant balance by different ways including interaction with hemoglobin (Hb) . METHODS: The effects of nitric oxide synthesis inhibition on the febrile response, hemoglobin-oxygen affinity and parameters of lipid peroxidation were studied in rabbits with fever . The fever was induced by intravenous administration of lipopolysaccharide from Salmonella typhi (0.6 microg/kg) . Mixed venous blood was taken before the administration and 60, 120 and 180 min after it . The following parameters were measured: half-saturation oxygen pressure (P(50)), concentrations of conjugated dienes, Schiff bases and alpha-tocopherol in plasma and red blood cells, and activity of catalase in red blood cells . RESULTS: The intravenous administration of the nitric oxide synthase inhibitor (N(omega)-nitro-L-arginine; 5x10(-3) M) reduced the lipopolysaccharide-induced rise in body temperature . After 180 min the actual P(50) had decreased from 35.0+/-1.7 to 29.4+/-1.3 mm Hg . An increase in the lipid peroxidation parameters and a decrease of the antioxidant system indices were observed . The administration of L-arginine to prevent nitric oxide synthase inhibition was accompanied by a shift of the oxyhemoglobin dissociation curve rightwards, more marked activation of the free radical processes and a greater elevation of body temperature . The multiple regression analysis showed a close linear correlation between P(50) and conjugated dienes, Schiff bases, alpha-tocopherol and catalase . CONCLUSION: These results suggest that the increased hemoglobin-oxygen affinity found after the inhibition of nitric oxide synthesis lowers the oxygen flow to tissues and its fraction utilized in free radical oxidations, which finally causes a reduction of the fever response to the lipopolysaccharide.

Emerg Infect Dis, 1999 Sep-Oct, 5(5), 607 - 25
Food-related illness and death in the United States; Mead PS et al.; To better quantify the impact of foodborne diseases on health in the United States, we compiled and analyzed information from multiple surveillance systems and other sources . We estimate that foodborne diseases cause approximately 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths in the United States each year . Known pathogens account for an estimated 14 million illnesses, 60, 000 hospitalizations, and 1,800 deaths . Three pathogens, Salmonella, Listeria, and Toxoplasma, are responsible for 1,500 deaths each year, more than 75% of those caused by known pathogens, while unknown agents account for the remaining 62 million illnesses, 265,000 hospitalizations, and 3,200 deaths . Overall, foodborne diseases appear to cause more illnesses but fewer deaths than previously estimated.

J Am Vet Med Assoc, 1999 Oct 1, 215(7), 973 - 7
Factors associated with prognosis for survival and athletic use in foals with septic arthritis: 93 cases (1987-1994); Steel CM et al.; OBJECTIVE: To identify factors affecting the prognosis for survival and athletic use in foals with septic arthritis . DESIGN: Retrospective study . ANIMALS: 93 foals with septic arthritis . PROCEDURE: Medical records were reviewed to obtain clinical findings, laboratory test results, radiographic findings, treatment method, and outcome . Race records for Thoroughbreds and Standardbreds were evaluated to determine whether foals subsequently raced and whether they raced successfully . RESULTS: 43 foals had 1 affected joint, 44 foals had multiple affected joints, and number of affected joints was not recorded for 6 foals . The femoropatellar and tarsocrural joints were most commonly affected . Osteomyelitis or degenerative joint disease were detected in 59% (46/78) of foals . Failure of passive transfer, pneumonia, and enteritis were common . Foals were treated with lavage, lavage and intra-articular administration of antibiotics, lavage and arthroscopic debridement with or without partial synovectomy, or lavage and arthrotomy to debride infected bone and systemic administration of antibiotics . Seventy-three foals survived to be discharged from hospital, and approximately a third raced . Isolation of Salmonella spp from synovial fluid was associated with an unfavorable prognosis for survival and multisystem disease was associated with an unfavorable prognosis for survival and ability to race; other variables were not significantly associated with survival and ability to race . CONCLUSIONS AND CLINICAL RELEVANCE: With treatment, the prognosis for survival of foals with septic arthritis was favorable, whereas prognosis for ability to race was unfavorable . Multisystem disease, isolation of Salmonella spp from synovial fluid, involvement of multiple joints, and synovial fluid neutrophil count > or = 95% at admission may be of prognostic value.

Emerg Infect Dis, 1999 Sep-Oct, 5(5), 626 - 34
Infections associated with eating seed sprouts: an international concern; Taormina PJ et al.; Recent outbreaks of Salmonella and Escherichia coli O157:H7 infections associated with raw seed sprouts have occurred in several countries . Subjective evaluations indicate that pathogens can exceed 107 per gram of sprouts produced from inoculated seeds during sprout production without adversely affecting appearance . Treating seeds and sprouts with chlorinated water or other disinfectants fails to eliminate the pathogens . A comprehensive approach based on good manufacturing practices and principles of hazard analysis and critical control points can reduce the risk of sprout-associated disease . Until effective measures to prevent sprout-associated illness are identified, persons who wish to reduce their risk of foodborne illness from raw sprouts are advised not to eat them; in particular, persons at high risk for severe complications of infections with Salmonella or E . coli O157:H7, such as the elderly, children, and those with compromised immune systems, should not eat raw sprouts.

J Med Microbiol, 1999 Oct, 48(10), 907 - 16
Intestinal colonisation of gnotobiotic pigs by Salmonella organisms: interaction between isogenic and unrelated strains; Lovell MA et al.; The effect of intestinal colonisation by a Salmonella strain on the establishment in the gut of an isogenic mutant administered orally 24 h after the first strain was studied in gnotobiotic pigs . Irrespective of the clinical outcome of the infection, the extensive colonisation of one Salmonella strain prevented a similar degree of colonisation by an otherwise isogenic antibiotic resistant strain; in some cases the second strain was hardly detectable . The poor colonisation of the challenge Salmonella strains was generally reflected in very low counts of organisms in the tissues . Colonisation by a strain of Escherichia coli reduced the rate of establishment of an isogenic E . coli, strain but did not prevent colonisation by an S . Typhimurium strain . S . Typhimurium with mutations in the tsr (serine chemotaxis receptor protein) or oxrA (transcriptional regulator of anaerobic metabolism) genes did not inhibit colonisation . Mutations in cya (adenylate cyclase), tar and trg (chemotaxis receptor proteins for aspartate and ribose respectively) genes were less inhibitory, while motB (non-motile) and cheR (impaired motility) mutants were fully inhibitory.

Antonie Van Leeuwenhoek, 1999 May, 75(4), 285 - 92
Prevalence of Salmonella serotypes in environmental waters and their relationships with indicator organisms; Polo F et al.; The incidence of serotypes of Salmonella in three types of environmental water (sea, river and fresh reservoirs) from north-east Spain was investigated . The study was performed at specific sampling locations during the summer for a period of five years (1992-1996) . A total of 823 strains were isolated and 55 different serotypes were identified, 42 were recovered from sea water, 32 from river water and 12 from freshwater reservoirs . The most frequently isolated serotypes coincided with those involved in clinical cases in the area studied . Salmonella enteritidis was the most common (111 isolates), it was found in all types of water, although most predominantly in sea water (16.1% of the isolates) . This serotype, together with S . hadar, significantly increased in frequency during the five year study period . The most frequent serotypes in river water and freshwater reservoirs were S . virchow (9.5%) and S . mikawasima (23.8%) respectively . Significant differences were assessed in the indicator organism densities between the samples with serotypes of clinical significance (S . enteritidis, S . infantis, S . typhimurium, S . virchow and S . paratyphi B) and those without clinical significance . Therefore their presence in all environmental waters may be of epidemiological significance.

Vet Microbiol, 1999 Aug 31, 68(3-4), 265 - 72
Salmonella Abortusequi strains of equine origin harbor a 95kb plasmid responsible for virulence in mice; Akiba M et al.; Most Salmonella choleraesuis subsp . choleraesuis serovar Abortusequi strains of equine origin harbor a 95kb plasmid, pSA95 . Results of PCR and Southern blot analysis suggest that pSA95 contains spv genes . A pSA95-cured strain of S . Abortusequi was 48 times less virulent to mice than its parental strain . Virulence was restored by reintroduction of pSA95 . These results provide clear evidence that pSA95 confers virulence on S . Abortusequi in mice . This is the first report describing a virulence plasmid of S . Abortusequi.

J Med Microbiol, 1999 Apr, 48(4), 367 - 74
Increase in incidence of resistance to ampicillin, chloramphenicol and trimethoprim in clinical isolates of Salmonella serotype Typhimurium with investigation of molecular epidemiology and mechanisms of resistance; Gallardo F et al.; Antimicrobial resistance patterns of Salmonella serotype Typhimurium isolates obtained during the period 1987-1994 were examined and the molecular epidemiology and the mechanisms of resistance to ampicillin, chloramphenicol and trimethoprim were investigated in 24 strains isolated during 1994 . Resistance to ampicillin increased from 18% to 78%, to chloramphenicol from 15% to 78%, to tetracycline from 53% to 89% and to co-trimoxazole from 3% to 37%, whereas resistance to norfloxacin remained at 0% . Of Salmonella serotype Typhimurium strains isolated during 1994, all ampicillin-resistant strains had an MIC > 256 mg/L, except one strain in which the MIC was 64 mg/L . Twelve strains (52%) had a TEM-type beta-lactamase, nine (39%) a CARB-type beta-lactamase and two strains (8%) had an OXA-type beta-lactamase . Chloramphenicol acetyl-transferase activity was detected in only nine (47%) of 19 chloramphenicol resistant strains, whereas all eight trimethoprim-resistant strains produced a dihydrofolate reductase type Ia enzyme . Three different epidemiological groups were defined by either low-frequency restriction analysis of chromosomal DNA and pulsed-field gel electrophoresis or repetitive extragenic palindromic-PCR . The latter technique provided an alternative, rapid and powerful genotyping method for S . Typhimurium . Although quinolones provide a good therapeutic alternative, the multiresistance of S . Typhimurium is of public health concern and it is important to continue surveillance of resistance levels and their mechanisms.

Teratology, 1999 Oct, 60(4), 190 - 205
Structural determinants of developmental toxicity in hamsters; Gomez J et al.; A CASE/MULTICASE structure activity relationship (SAR) model of developmental toxicity of chemicals in hamsters (HaDT) was developed . The model exhibited a predictive performance of 74% . The model's overall predictivity and informational content were similar to those of an SAR model of mutagenicity in Salmonella . However, unlike the Salmonella mutagenicity model, the HaDT model did not identify overtly chemically reactive moieties as associated with activity . Moreover, examination of the number and nature of significant structural determinants suggested that developmental toxicity in hamsters was not the result of a unique mechanism or attack on a specific molecular target . The analysis also indicated that the availability of experimental data on additional chemicals would improve the performance of the SAR model .

Mol Cell Probes, 1999 Oct, 13(5), 341 - 7
Comparison of different primers for rapid detection of Salmonella using the polymerase chain reaction; Gooding CM et al.; Salmonella is the leading cause of food-borne diarrhoeas in the US . In recent years polymerase chain reaction (PCR) has become the method of choice for rapid and sensitive detection of Salmonellae in contaminated foods . As a result, several different primer sets have been reported for use in PCR-based assay systems . In order to identify an optimal primer set from among the wide range of primers reported in the literature, we synthesized five different pairs and evaluated their relative performance in PCR under uniform assay conditions using a common panel of the target (Salmonella) and non-target (non- Salmonella) bacterial strains . Of the five sets of primers tested, the one designed on the basis of a 199 bp repeat sequence of S . weltevreden{Jitrapakdee et al . (1995) Molecular and Cellular Probes 9, 375-382} gave optimal results with most bacterial strains examined .

Appl Environ Microbiol, 1999 Oct, 65(10), 4329 - 33
The outer membrane of gram-negative bacteria inhibits antibacterial activity of brochocin-C; Gao Y et al.; Brochocin-C is a two-peptide bacteriocin produced by Brochothrix campestris ATCC 43754 that has a broad activity spectrum comparable to that of nisin . Brochocin-C has an inhibitory effect on EDTA-treated gram-negative bacteria, Salmonella enterica serovar Typhimurium lipopolysaccharide mutants, and spheroplasts of Typhimurium strains LT2 and SL3600 . Brochocin-C treatment of cells and spheroplasts of strains of LT2 and SL3600 resulted in hydrolysis of ATP . The outer membrane of gram-negative bacteria protects the cytoplasmic membrane from the action of brochocin-C . It appears that brochocin-C is similar to nisin and possibly does not require a membrane receptor for its function; however, the difference in effect of the two bacteriocins on intracellular ATP indicates that they cause different pore sizes in the cytoplasmic membrane.

Antimicrob Agents Chemother, 1999 Oct, 43(10), 2430 - 6
Propagation of TEM- and PSE-type beta-lactamases among amoxicillin-resistant Salmonella spp . isolated in France; Llanes C et al.; A survey conducted between 1987 and 1994 at the University Hospital of Besancon, France, demonstrated a dramatic increase (from 0 to 42 . 5%) in the prevalence of amoxicillin resistance among Salmonella spp . Of the 96 resistant isolates collected during this period (including 77 Typhimurium), 54 were found to produce TEM-1 beta-lactamase, 40 produced PSE-1 (equivalent to CARB-2), one produced PSE-1 plus TEM-2, and one produced OXA-1 in isoelectric focusing and DNA hybridization experiments . Plasmids coding for these beta-lactamases were further characterized by (i) profile analysis, (ii) restriction fragmentation pattern analysis, (iii) hybridization with an spvCD-orfE virulence probe, and (iv) replicon typing . In addition, isolates of S . typhimurium were genotypically compared by pulsed-field gel electrophoresis of XbaI-macrorestricted chromosomal DNA . Altogether, these methods showed that 40 of the 41 PSE-1 producers were actually the progeny of a single epidemic S . typhimurium strain lysotype DT104 . Isolates of that strain were found to harbor RepFIC virulence plasmids with somewhat different restriction profiles, but which all carried the bla(PSE-1) gene . Of these virulence/resistance plasmids, 15 were transmissible to Escherichia coli . TEM-1-producing S . typhimurium displayed much greater genotypic and plasmidic diversities, suggesting the acquisition of the bla(TEM-1) gene from multiple bacterial sources by individual strains . In agreement with this, 32 of the 35 S . typhimurium plasmids encoding TEM-1 were found to be conjugative . These data show that development of amoxicillin resistance among Salmonella, especially in serovar Typhimurium, results from both gene transfers and strain dissemination.

Vaccine, 1999 Oct 1, 17 Suppl 2, S22 - 7
Duration of efficacy of Ty21a, attenuated Salmonella typhi live oral vaccine; Levine MM et al.; Currently, two different formulations of Ty21a live oral typhoid vaccine are commercialized . The enteric-coated capsule formulation was licensed based on results of three years of follow-up of a randomized, placebo-controlled, double-blind field trial in Area Occidente, Santiago, Chile, which demonstrated that three doses of this formulation, given on an every other day immunization schedule, conferred the best protection among several options evaluated . Subsequently, a liquid formulation (lyophilized vaccine organisms reconstituted with buffer and water into a vaccine cocktail) was commercialized after it was shown to provide superior protection than enteric-coated capsules over three years of follow-up in a randomized, placebo-controlled field trial in Area Sur Oriente and Area Norte, Santiago . Surveillance in the Area Occidente trial was continued for four additional years (i.e., total seven years of follow-up) and in the Area Sur Oriente/Area Norte trial for two additional years (i.e., a total of five years of follow-up) . These additional surveillance data, which were analyzed to ascertain the longevity of protection conferred by these formulations of Ty21a, revealed that three doses of Ty21a in enteric-coated capsules (every other day schedule) conferred 67% protection over three years and 62% protection over seven years of follow-up, whereas three doses of liquid formulation (every other day schedule) elicited 77% protection over three years and 78% over five years of follow-up . Based on its excellent clinical acceptability, ease of oral administration, proven practicality in school-based mass immunization, and long-term efficacy enduring at least seven years, it is proposed that school-based immunization with Ty21a be utilized as a control measure in areas where the incidence of typhoid fever is high and Salmonella typhi are antibiotic-resistant.

Vaccine, 1999 Oct 1, 17 Suppl 2, S1 - 5
BERNA: a century of immunobiological innovation; Cryz SJ; At the time the Swiss Serum and Vaccine Institute Berne (BERNA) was found in 1898, few vaccines or immune globulins were available . This short list included vaccines against cholera, typhoid fever, plague, smallpox and rabies and equine anti-tetanus and diphtheria immune globulins . Furthermore, their use was restricted due to limited production capacity, uncertainty regarding safety and no public health infrastructure to promote their utilization . Today, safe and effective vaccines exist for more than 30 infectious diseases while human hyperimmune globulins exist to treat or prevent rabies, tetanus, respiratory syncytial virus, cytomegalovirus, hepatitis A, hepatitis B, and herpes virus (Varicella zoster) infections . Throughout its 100 years of existence, BERNA has played a key role in the evolution of the field by introducing novel technology leading to safer, and more efficacious vaccines . It was a pioneer in the development of freeze dried smallpox vaccine free from bacterial contamination . The Salmonella typhi Ty21a typhoid fever vaccine strain demonstrated that oral immunization against enteric bacterial pathogens was not only feasible, but could be accomplished with a virtual lack of attendant adverse reactions . This finding has served as an impetus to develop other live attenuated bacterial strains not only as vaccines, but also as vectors for vaccine antigens and gene therapy . One such example is Vibrio cholerae CVD 103-HgR, the first live vaccine for human use derived through recombinant DNA technology . Subsequent studies have shown that these two vaccine strains can be combined without sacrificing safety or immunogenicity, setting the cornerstone for combined orally administered vaccines . Recently, a novel vaccine antigen delivery system, termed virosomes, has been utilized to construct hepatitis A and influenza vaccines . Such vaccines elicit fewer local adverse reactions than their classical counterparts and display enhanced immunogenicity . Virosome-formulated influenza vaccine has also been shown to be safe and immunogenic, when administered by the intranasal route.

Carcinogenesis, 1999 Oct, 20(10), 1919 - 26
Inhibition of dibenzo{a,l}pyrene-induced multi-organ carcinogenesis by dietary chlorophyllin in rainbow trout; Reddy AP et al.; Cancer chemoprevention by dietary chlorophyllin (CHL) was investigated in a rainbow trout multi-organ tumor model . In study 1, duplicate groups of 130 juvenile trout were treated for 2 weeks with control diet, 500 p.p.m . dibenzo{a,l}pyrene (DB{a,l}P) or 500 p.p.m . DB{a,l}P + 2052 p.p.m . CHL, then returned to control diet . DB{a,l}P alone proved somewhat toxic but induced high tumor incidences in liver (61%), stomach (91%) and swimbladder (53%) 11 months after initiation . CHL co-feeding abrogated DB{a,l}P acute toxicity and reduced tumor incidences to 18% in liver, 34% in stomach and 3% in swimbladder (P </= 0.01) . A second tumor and DNA adduct study using a non-toxic initiation protocol (200 p.p.m . DB{a,l}P +/- 4000 p.p.m . CHL for 4 weeks) confirmed these results . Potential CHL inhibitory mechanisms were investigated . Dietary CHL inhibited hepatic DB{a, l}P-DNA adducts in the two tumor studies by 89 and 76%, respectively . CHL was shown to complex strongly with DB{a,l}P (K(d1,2) = 1.59 +/- 0.01 microM, stoichiometry 2CHL:DB{a,l}P) and strongly inhibited DB{a,l}P mutagenesis in the Salmonella assay . Significant inhibition occurred at CHL concentrations substantially less than stoichiometric with DB{a,l}P and thus not reflecting simple DB{a,l}P sequestration via complexation . These initial findings suggest that CHL chemoprevention reflects complexation that might limit DB{a,l}P uptake in vivo, antimutagenic mechanisms such as catalytic degradation of the proximate electrophile in target cells, or both . These results demonstrate that dietary CHL is a reproducibly effective chemopreventive agent for DB{a,l}P multi-organ tumorigenesis in trout and suggest that reduced DB{a,l}P-DNA adducts may be predictive biomarkers of CHL reduction of DB{a,l}P-initiated hepatic tumors.

Pediatr Hematol Oncol, 1999 Sep-Oct, 16(5), 473 - 6
Acalculous cholecystitis caused by Salmonella paratyphi B infection in a child with acute pre-B-cell lymphoblastic leukemia; Erduran E et al.; Acute acalculous cholecystitis (AC) rarely occurs in children with acute leukemia . The principal treatment modality of AC is emergency surgery . Medical treatment of AC is not a good therapeutic approach . The mortality rate of AC is approximately 100% for medical treatment and 10-15% for emergency surgery . A 9-year-old boy with acute pre-B-cell lymphoblastic leukemia and AC caused by Salmonella paratyphi B infection is presented . He was successfully treated with cefepime, amikacin, and granulocyte-colony stimulating factor (G-CSF) . These treatment combinations led to uneventful recovery after 21 days . It appears that AC in children with acute leukemia may be treated with appropriate intravenous antibiotics . This may be the first case of AC caused by Salmonella paratyphi B infection reported in a child with acute pre-B-cell lymphoblastic leukemia.

Environ Health Perspect, 1999 Oct, 107(10), 805 - 12
p53 induction as a genotoxic test for twenty-five chemicals undergoing in vivo carcinogenicity testing; Duerksen-Hughes PJ et al.; In vivo carcinogenicity testing is an expensive and time-consuming process, and as a result, only a relatively small fraction of new and existing chemicals has been tested in this manner . Therefore, the development and validation of alternative approaches is desirable . We previously developed a mammalian in vitro assay for genotoxicity based on the ability of cells to increase their level of the tumor-suppressor protein p53 in response to DNA damage . Cultured cells are treated with various amounts of the test substances, and at defined times following treatment, they are harvested and lysed . The lysates are analyzed for p53 by Western blot and/or enzyme-linked immunosorbent assay analysis . An increase in cellular p53 following treatment is interpreted as evidence for DNA damage . To determine the ability of this p53-induction assay to predict carcinogenicity in rodents and to compare such results with those obtained using alternate approaches, we subjected 25 chemicals from the predictive toxicology evaluation 2 list to analysis with this method . Five substances (citral, cobalt sulfate heptahydrate, D&C Yellow No . 11, oxymetholone, and t-butylhydroquinone) tested positive in this assay, and three substances (emodin, phenolphthalein, and sodium xylenesulfonate) tested as possibly positive . Comparisons between the results obtained with this assay and those obtained with the in vivo protocol, the Salmonella assay, and the Syrian hamster embryo (SHE) cell assay indicate that the p53-induction assay is an excellent predictor of the limited number of genotoxic carcinogens in this set, and that its accuracy is roughly equivalent to or better than the Salmonella and SHE assays for the complete set of chemicals.

Cancer Lett, 1999 Sep 1, 143(2), 113 - 6
Establishment of a Salmonella tester strain highly sensitive to mutagenic heterocylic amines; Kamataki T et al.; A co-expression plasmid (p1A2OR) carrying human CYP1A2 and NADPH-P450 reductase cDNAs and an expression plasmid (pOAT) carrying Salmonella TA1538/ARO cells . The CYP and OAT expressed in the Salmonella cells showed catalytic activity . The TA1538/ARO strain exhibited high sensitivity to heterocyclic amines (HCAs) such as 2-amino-3,4-dimethylimidazo{4,5-f}quinoline (MeIQ), 2-amino-3-methylimidazo{4,5-f}quinoline (IQ), 2-amino-3,8-dimenthylimidazo{4,5-f}quinoline (MeIQx), 2-amino-1-methyl-6-phenylimidazo{4,5-b}pyridine (PhIP) as compared with the parent Ames tester strain TA1538 . It is suggested that the intracellular expression of drug-metabolising enzymes makes the Salmonella cells highly sensitive to the HCAs.

Lancet . 1999 Sep 18;354(9183):1004.
Myocarditis due to Salmonella virchow and sudden infant death; Neuwirth C et al.; A strain of Salmonella virchow was isolated in the myocardium of a 1 1/2 month child who died suddenly . The source of contamination was the water of a family aquarium containing turtles.

Nature, 1999 Sep 16, 401(6750), 293 - 7
A salmonella protein antagonizes Rac-1 and Cdc42 to mediate host-cell recovery after bacterial invasion; Fu Y et al.; An essential feature of the bacterial pathogen Salmonella spp . is its ability to enter cells that are normally non-phagocytic, such as those of the intestinal epithelium . The bacterium achieves entry by delivering effector proteins into the host-cell cytosol by means of a specialized protein-secretion system (termed type III), which causes reorganization of the cell's actin cytoskeleton and ruffling of its membrane . One of the bacterial effectors that stimulates these cellular responses is SopE, which acts as a guanyl-nucleotide-exchange factor on Rho GTPase proteins such as Cdc42 and Rac . As the actin-cytoskeleton reorganization induced by Salmonella is reversible and short-lived, infected cells regain their normal architecture after bacterial internalization . We show here that the S . Typhimurium effector protein SptP, which is delivered to the host-cell cytosol by the type-III secretion system, is directly responsible for the reversal of the actin cytoskeletal changes induced by the bacterium . SptP exerts this function by acting as a GTPase-activating protein (GAP) for Rac-1 and Cdc42.

J Bacteriol, 1999 Oct, 181(19), 5967 - 75
The propanediol utilization (pdu) operon of Salmonella enterica serovar Typhimurium LT2 includes genes necessary for formation of polyhedral organelles involved in coenzyme B(12)-dependent 1, 2-propanediol degradation; Bobik TA et al.; The propanediol utilization (pdu) operon of Salmonella enterica serovar Typhimurium LT2 contains genes needed for the coenzyme B(12)-dependent catabolism of 1,2-propanediol . Here the completed DNA sequence of the pdu operon is presented . Analyses of previously unpublished pdu DNA sequence substantiated previous studies indicating that the pdu operon was acquired by horizontal gene transfer and allowed the identification of 16 hypothetical genes . This brings the total number of genes in the pdu operon to 21 and the total number of genes at the pdu locus to 23 . Of these, six encode proteins of unknown function and are not closely related to sequences of known function found in GenBank . Two encode proteins involved in transport and regulation . Six probably encode enzymes needed for the pathway of 1,2-propanediol degradation . Two encode proteins related to those used for the reactivation of adenosylcobalamin (AdoCbl)-dependent diol dehydratase . Five encode proteins related to those involved in the formation of polyhedral organelles known as carboxysomes, and two encode proteins that appear distantly related to those involved in carboxysome formation . In addition, it is shown that S . enterica forms polyhedral bodies that are involved in the degradation of 1,2-propanediol . Polyhedra are formed during either aerobic or anaerobic growth on propanediol, but not during growth on other carbon sources . Genetic tests demonstrate that genes of the pdu operon are required for polyhedral body formation, and immunoelectron microscopy shows that AdoCbl-dependent diol dehydratase is associated with these polyhedra . This is the first evidence for a B(12)-dependent enzyme associated with a polyhedral body . It is proposed that the polyhedra consist of AdoCbl-dependent diol dehydratase (and perhaps other proteins) encased within a protein shell that is related to the shell of carboxysomes . The specific function of these unusual polyhedral bodies was not determined, but some possibilities are discussed.

Infect Immun, 1999 Oct, 67(10), 5253 - 7
CD40-CD40 ligand interactions augment survival of normal mice, but not CD40 ligand knockout mice, challenged orally with Salmonella dublin; Marriott I et al.; Interactions between CD40 expressed on macrophages and CD40 ligand expressed on T lymphocytes can be an important signal for optimal macrophage activation . Previous studies have demonstrated that the optimal response against certain intracellular pathogens (e.g., Crytosporidium and Leishmania spp.) by macrophages requires CD40-CD40 ligand interactions . However, this finding is not universal, since two recent reports utilizing CD40 knockout mice have shown no such contribution to the protective immune response against Mycobacterium tuberculosis or Histoplasma capsulatum . We demonstrate here that CD40-CD40 ligand interactions are significant events in the protective response against the intracellular pathogen Salmonella dublin in normal mice but not for animals genetically deficient in CD40 ligand expression . Treating BALB/c mice exogenously with a CD40 agonist (i.e., soluble trimeric CD40 ligand) increased resistance against a lethal, orally administered dose of S . dublin . Conversely, in vivo administration of a monoclonal antibody against CD40 ligand to block endogenous CD40-CD40 ligand interactions resulted in a decreased resistance to salmonellosis . In contrast, CD40 ligand knockout mice demonstrated no increased susceptibility to salmonellosis . In vitro treatment of Salmonella-infected macrophages from BALB/c mice with soluble trimeric CD40 ligand resulted in an elevated production of interleukin 12p70 by these cells, suggesting a mechanism whereby CD40-CD40 ligand interactions might enhance protective immune responses to this pathogen . Taken together, these studies strongly suggest that CD40-CD40 ligand interactions in normal mice play an important protective role in immune responses against the gram-negative, intracellular pathogen S . dublin.

Infect Immun, 1999 Oct, 67(10), 5176 - 85
Induction of cytokine synthesis by flagella from gram-negative bacteria may be dependent on the activation or differentiation state of human monocytes; Ciacci-Woolwine F et al.; We have previously demonstrated that salmonellae, but not Escherichia coli or Yersinia enterocolitica, stimulates tumor necrosis factor alpha (TNFalpha) production in the human promonocytic cell line U38 . Subsequent analysis revealed that the TNFalpha-inducing activity of salmonellae was associated with flagellin, a major component of flagella from gram-negative bacteria . In the present study, we have explored the basis for the apparent specificity of action of Salmonella flagella on TNFalpha expression in U38 cells and have extended this analysis to normal human peripheral blood mononuclear cells (PBMC) . Flagella from the enteropathogenic E . coli strain E2348/69, Y . enterocolitica JB580, and Pseudomonas aeruginosa PAO1, which did not induce significant levels of TNFalpha production in U38 cells, were as potent as Salmonella flagella in terms of TNFalpha and interleukin 1beta activation in PBMC . However, TNFalpha production in U38 cells was greatly enhanced when these cells were stimulated with flagella from E . coli, Y . enterocolitica, and P . aeruginosa in the presence of a costimulant, phorbol 13-myristate acetate . These findings are consistent with the hypothesis that the activation or differentiation state of a monocyte may have a substantial effect on the cell's responsiveness to flagellum stimulation of cytokine synthesis . Furthermore, these results indicate that cytokine induction in monocytes may be a general property of flagella from gram-negative bacteria.

Infect Immun, 1999 Oct, 67(10), 5133 - 41
Use of in vivo-regulated promoters to deliver antigens from attenuated Salmonella enterica var . Typhimurium; Dunstan SJ et al.; This study describes the construction and analysis of three in vivo-inducible promoter expression plasmids, containing pnirB, ppagC, and pkatG, for the delivery of foreign antigens in the DeltaaroAD mutant of Salmonella enterica var . Typhimurium (hereafter referred to as S . typhimurium) . The reporter genes encoding beta-galactosidase and firefly luciferase were used to assess the comparative levels of promoter activity in S . typhimurium in vitro in response to different induction stimuli and in vivo in immunized mice . It was determined that the ppagC construct directed the expression of more beta-galactosidase and luciferase in S . typhimurium than the pnirB and pkatG constructs, both in vitro and in vivo . The gene encoding the C fragment of tetanus toxin was expressed in the aroAD mutant of S . typhimurium (BRD509) under the control of the three promoters . Mice orally immunized with attenuated S . typhimurium expressing C fragment under control of the pagC promoter {BRD509(pKK/ppagC/C frag)} mounted the highest tetanus toxoid-specific serum antibody response . Levels of luciferase expression in vivo and C-fragment expression in vitro from the pagC promoter appeared to be equivalent to if not lower than the levels of expression detected with the constitutive trc promoter . However, mice immunized with BRD509(pKK/ppagC/C frag) induced significantly higher levels of tetanus toxoid-specific antibody than BRD509(pKK/C frag)-immunized mice, suggesting that the specific location of foreign antigen expression may be important for immunogenicity . Mutagenesis of the ribosome binding sites (RBS) in the three promoter/C fragment expression plasmids was also performed . Despite optimization of the RBS in the three different promoter elements, the expression levels in vivo and overall immunogenicity of C fragment when delivered to mice by attenuated S . typhimurium were not affected . These studies suggest that in vivo-inducible promoters may give rise to enhanced immunogenicity and increase the efficacy of S . typhimurium as a vaccine vector.

Infect Immun, 1999 Oct, 67(10), 5021 - 6
Limited interleukin-18 response in Salmonella-infected murine macrophages and in Salmonella-infected mice; Elhofy A et al.; Optimal immune responses against an intracellular bacterial pathogen, such as Salmonella, involve the production of gamma interferon (IFN-gamma), which activates macrophages . It has recently been suggested that, interleukin-18 (IL-18), in addition to IL-12, contributes to the induction of IFN-gamma following infection . Given this hypothesis, an optimal host immune response against intracellular bacterial pathogens would include the induction of IL-18 secretion by macrophages due to Salmonella infection . We questioned whether Salmonella could induce macrophages to upregulate their expression of IL-18 mRNA and secretion of IL-18 . With cultures of murine macrophages, we were surprised to find that infection by wild-type Salmonella dublin resulted in decreased expression of IL-18 mRNA and IL-18 secretion rather than an increase . Reduction of macrophage-derived IL-18 expression by wild-type Salmonella occurred early in the response, suggesting a direct effect . Furthermore, mice orally inoculated with wild-type Salmonella were shown to have reduced IL-18 mRNA expression at mucosal sites within hours postinoculation . Together these studies demonstrate Salmonella-induced reductions in IL-18 expression, suggesting that this intracellular pathogen may be capable of limiting a potentially protective immune response.

J Leukoc Biol, 1999 Sep, 66(3), 382 - 90
Endogenous IL-15 might be responsible for early protection by natural killer cells against infection with an avirulent strain of Salmonella choleraesuis in mice; Hirose K et al.; Interleukin (IL)-15 is a novel cytokine with growth factor activity for T cells, B cells, and natural killer cells (NK cells) . We investigated the role of IL-15 in the host defense against infection with avirulent Salmonella choleraesuis strain 31N-1 cured of 50-kb virulent plasmid . IL-15 was abundantly expressed at transcription and protein levels in macrophages infected with S . choleraesuis 31N-1 . The number of NK cells in the infected sites was increased during the course of infection coincident with IL-15 production . Anti-IL-15 mAb administration inhibited the emergence of NK cells and interferon-gamma (IFN-gamma) production in serum after infection with S . choleraesuis 31N-1 and concurrently impaired the clearance of the bacteria . These results suggested that IL-15 might be responsible for protection against avirulent S . choleraesuis infection at early stage of infection through activation of NK cells in the infected sites.

Electrophoresis, 1999 Aug, 20(11), 2241 - 7
Defining protease specificity with proteomics: a protease with a dibasic amino acid recognition motif is regulated by a two-component signal transduction system in Salmonella; Adams P et al.; Microbial proteases play diverse and important roles in bacterial virulence but their detection and characterisation is often hampered by their limited abundance or lack of expression in the absence of suitable environmental signals . We describe here a sensitive proteomic approach to detect proteases that are under the control of a virulence regulator and to characterise their recognition motifs . Using MG++-depleted growth media or a mutant strain of Salmonella in which the PhoP-PhoQ virulence regulatory system is constitutively active, truncated forms of DnaK, elongation factor G, elongation factor Tu and ribosomal protein S1 proteins were detected . Two other global regulatory mutants and cells exposed to acid or to oxidative stress failed to produce the truncated proteins, indicating specific control of the protease activity by the PhoP-PhoQ system . Our results suggest that at least two proteases are induced . To define the proteolytic cleavage sites of one of the proteases, peptides from each of the truncated proteins were identified by tryptic mass fingerprinting/nanoelectrospray mass spectrometry and mapped onto the sequence of the intact protein . Alignment of the regions around the cut site indicates that the protease recognises a dibasic amino acid motif characteristic of the omptin protease family . The induction of such proteases in bacteria depleted of Mg++ ions may contribute to the PhoPQ-mediated resistance of Salmonella to cationic antimicrobial peptides . Additionally, our results suggest it would be prudent to keep the concentration of this ion above micromolar levels during bacterial sample preparation for proteomic analyses.

Avian Dis, 1999 Jul-Sep, 43(3), 597 - 9
Occurrence of Salmonella enteritidis in pooled table eggs and market-ready chicken carcasses in Zambia; Hang'ombe BM et al.; The level of Salmonella enteritidis contamination in Zambian table eggs and ready market chicken carcasses was studied . Nine of the 240 (3.8%) pooled samples of table eggs and 18 of 382 (4.7%) chicken carcasses were contaminated with S . enteritidis . All the isolates from the table eggs belonged to the enteropathogenic invasive phage type 4, whereas seven isolates from the chicken carcasses belonged to phage type 4, three were phage type 7, and eight were untypable (rough type) . All the isolates were sensitive to gentamycin, ampicillin, tetracycline, cotrimoxazole, amoxycillin, furazolidone, and chloramphenicol.

Avian Dis, 1999 Jul-Sep, 43(3), 538 - 48
Effect of induced molting on heterophil function in White Leghorn hens; Kogut MH et al.; This study was undertaken to determine the effects of induced molt on basal functional activities of heterophils from aging hens . For this purpose, heterophils from both molted and unmolted hens were examined by in vitro bioassays for functional responsiveness and efficiency . We evaluated the ability of the heterophils to migrate to chemotactic stimuli, phagocytize opsonized and nonopsonized Salmonella-enteritidis (SE), and generate an oxidative burst in response to inflammatory agonists . A significant (P < 0.001) heterophilia was found in the molted hens within 2 days after feed withdrawal and remained throughout the length of the experimental feed withdrawal period . No significant differences were found in the random migration of heterophils from either group . The chemotactic movement of heterophils from molted hens was not affected until 8 days after feed withdrawal when compared with heterophil chemotaxis from unmolted hens . A significant decrease in chemotaxis by the heterophils from molted hens was observed days 8-12 after feed withdrawal (P < 0.05) . Significantly (P < 0.05) fewer heterophils from molted hens were able to phagocytize opsonized (59% vs . 38%) and nonopsonized (26% vs . 15%) SE within 2 days after feed withdrawal . Likewise, significantly (P < 0.05) fewer bacteria were phagocytized per heterophil from the molted hens when compared with the number of bacteria per heterophil from the unmolted hens . The oxidative burst of heterophils stimulated by either opsonized zymosan A or phorbol myristate acetate of heterophils from molted hens was significantly (P < 0.05) reduced when compared with that generated by heterophils from the unmolted hens . These results indicate that feed withdrawal to induce molt alters the number and function of peripheral blood heterophils . This decreased efficiency of heterophil functional activity appears to play a role in the increased susceptibility of molting hens to SE infections.

Avian Dis, 1999 Jul-Sep, 43(3), 506 - 15
Pathogenicity of Salmonella enteritidis phage types 4, 8, and 23 in broiler chicks; Dhillon AS et al.; Four hundred fifty day-old Hubbard broiler chicks were subdivided into 15 groups of 30 chicks each . Six groups of chicks received 0.5 ml of broth culture containing 5 x 10(6) colony-forming units (CFU) of Salmonella enteritidis (SE) phage types (PTs) 4, 8, and 23 by crop gavage . Similarly, six other groups received 0.5 ml containing 5 x 10(8) CFU of SE . One group was inoculated with 0.5 ml containing 5 x 10(6) CFU of Salmonella pullorum, and another group received 0.5 ml containing 5 x 10(8) CFU of S . pullorum . A group of 30 chicks were kept as uninoculated controls . Chicks were observed daily for clinical signs and mortality . All birds were weighed at 7, 14, and 21 days postinoculation 21 (DPI) . Four chicks were randomly selected from each treatment group, euthanatized, and necropsied at 7 and 14 DPI . Gross lesions were recorded and selected tissues were collected for histopathology . The higher rates of illness and mortality were observed in chicks inoculated with 5 x 10(6) and 5 x 10(8) CFU of S . pullorum, followed by SE PT4 of human origin and SE PT4 of chicken origin . Moderate to high mortality was observed in chicks inoculated with the higher dose of SE isolates that belonged to PT8 and one SE of PT23 . Variable mortality was evident in groups inoculated with the lower dose of salmonella . The most consistent gross and histopathologic changes, including fibrinous pericarditis and perihepatitis, were seen in the dead birds from various treatment groups . The lower mean body weights were present in all treatment groups compared with uninoculated controls . No illness or mortality was observed in uninoculated control groups.

Avian Dis, 1999 Jul-Sep, 43(3), 497 - 505
Evaluation of the efficacy of Salmonella enteritidis oil-emulsion bacterin in an intravaginal challenge model in hens; Miyamoto T et al.; The efficacy of Salmonella enteritidis (SE) oil-emulsion bacterin (a commercially available vaccine) was evaluated in an intravaginal challenge model in hens producing a high rate of SE-contaminated eggs . Hens were vaccinated at 38 wk of age . A second (booster) bacterin injection was administered 4 wk later . Two weeks after the second vaccination, all hens were challenged intravaginally with 10(7) colony-forming units of SE . After challenge, 36 of 189 eggs (19.0%) in the vaccinated hens were positive for SE, and this contamination rate was significantly (P < 0.01) lower than that in the unvaccinated hens (61 of 165 eggs, 37.0%) . SE was highly recovered from the cloacal and vaginal swabs of the unvaccinated and vaccinated hens, but the number of SE from the cloaca of the vaccinated hens was significantly (P < 0.05) lower than that in the unvaccinated hens at 7 days post-challenge (PC) . The recoveries of SE from the spleen and ovary in the vaccinated hens were significantly (P < 0.05) lower than those in the unvaccinated hens at 7 days PC . At necropsy, SE was recovered from 2 of 15 forming eggs (13.3%) taken from the oviducts of the unvaccinated hens, whereas no SE was recovered from 17 forming eggs in the vaccinated hens . After vaccination, serum antibodies for SE in the vaccinated hens were significantly higher than those in the unvaccinated hens . Antibodies from the oviductal washing, especially immunoglobulin G isotype, in the vaccinated hens were higher than those in the unvaccinated hens after challenge . This intravaginal challenge model produced frequent contaminated eggs and clearly demonstrated the ability of the bacterin to protect against egg contamination . The present model may be a useful tool for further studies to evaluate the protective effect against SE contamination of eggs by potential vaccine candidates.

East Afr Med J, 1998 Sep, 75(9), 512 - 5
Escherichia coli in patients with acute gastroenteritis in Lagos, Nigeria; Akinyemi KO et al.; Over a period of 12 months, a total of 852 stool samples from patients (both children and adults) with acute diarrhoeal diseases attending some public and government recognised health institutions in Lagos metropolis were screened for diarrhoeagenic bacterial agents . One hundred and eighty two bacterial isolates were found out of which 83 (45.6%) were Escherichia coli, 38 (20.9%) Shigella spp, 31 (17%) Salmonella spp, 16 (8.8%) Klebsiella spp, eight (4.4%) Aeromonas spp, while there were only six (3.3%) isolates for Plesiomonas spp . Of the 83 isolates for E . coli group, 49 (59%) were enteropathogenic (EPEC), 17 (20.5%) enterotoxigenic (ETEC), 10 (12.1%) enteroinvasive (EIEC) and seven (8.4%) enterohaemorrhagic (EHEC) . The EPEC strains particularly serotype 055, were mostly encountered in children aged over five years . On the other hand, EIEC and ETEC strains were found mainly in adults while EHEC O157: H7 strains occurred in all the age groups studied . This study further stresses the important role of EIEC and ETEC in acute diarrhoeal diseases and the possible implication of EHEC in acute gastroenteritis, especially in children in Lagos, Nigeria.

J Food Prot, 1999 Sep, 62(9), 980 - 5
Inactivation of Salmonella and Listeria in ground chicken breast meat during thermal processing; Murphy RY et al.; Thermal inactivation of six Salmonella spp . and Listeria innocua was evaluated in ground chicken breast and liquid medium . Survival of Salmonella and Listeria was affected by the medium composition . Under the same thermal process condition, significantly more Salmonella and Listeria survived in chicken breast meat than in 0.1% peptone-agar solution . The thermal lethality of six tested Salmonella spp . was additive in chicken meat . Survival of Listeria in chicken meat during thermal processing was not affected by the presence of the six Salmonella spp . Sample size and shape affected the inactivation of Salmonella and Listeria in chicken meat during thermal processing.

Commun Dis Public Health, 1999 Sep, 2(3), 207 - 9
Pulsed field gel electrophoresis identifies an outbreak of Salmonella enterica serotype Montevideo infection associated with a supermarket hot food outlet; Threlfall EJ et al.; In February 1996 Salmonella enterica serotype Montevideo infection in a patient in the North Tyneside area was attributed to consumption of cooked chicken bought from a supermarket hot food outlet . Isolates from the patient, leftover food, and environmental samples were indistinguishable by pulsed field gel electrophoresis (PFGE) . PFGE also demonstrated that an outbreak of infection with S . Montevideo associated with the hot food outlet had occurred in late 1995 and early 1996 . This study shows the importance of microbial strain discrimination in outbreak investigations and illustrates the value of close liaison between microbiologists, epidemiologists, and environmental health officers in the control of salmonella outbreaks.

Int J Food Microbiol, 1999 Aug 15, 49(3), 169 - 71
Occurrence of Salmonella spp . in imported eggs into Albania; Telo A et al.; Seventy-nine shell egg lots imported into Albania during the 2-years period 1996-1997 (69 lots during 1996 and 10 lots during 1997) were investigated for the presence of the Salmonella spp . Salmonella was detected in 1 out of 79 analysed pooled samples (1.26%) . The Salmonella strain was isolated only from the egg shell, but not from the liquid part . The isolated strain was biochemically identified by the API 20 E system . Following biochemical identification, it was serotyped with Salmonella monovalent sera at the Institute of Public Health, Tirana, Albania and was found belonging to the Salmonella group C . The lot in which Salmonella was detected consisted of 275000 eggs.

Int J Food Microbiol, 1999 Aug 15, 49(3), 161 - 7
Efficacy of disinfection of shell eggs externally contaminated with Salmonella enteritidis . Implications for egg testing; Himathongkham S et al.; Experimental contamination of the surface of shell eggs by dipping in a culture of Salmonella enteritidis resulted in the presence of Salmonella enteritidis in/on the shells as well as shell membranes but not in the egg content . Disinfection with Lugol's solution, chlorhexidine, ethanol, quarternary ammonium solutions or flaming after dipping in ethanol failed to achieve complete decontamination of the shell and membranes with resulting false positives when eggs were broken for culturing of the content . Dipping eggs for three seconds in boiling water resulted in complete destruction of Salmonella enteritidis in shells and membranes but sometimes caused the eggs to crack . A method of aseptically opening eggs without risk of contaminating the content from the shell or membrane was developed . Salmonella enteritidis deposited in/on the shell and membranes did not multiply during storage of the eggs at 20 degrees C for four weeks, the counts seemed to decrease . No Salmonella enteritidis was detected in the contents of any contaminated eggs.

Vet Parasitol, 1999 Sep 1, 85(4), 245 - 57
Role of Cryptosporidium parvum as a pathogen in neonatal diarrhoea complex in suckling and dairy calves in France; Naciri M et al.; This study was carried out to find the importance of Cryptosporidium parvum in diarrhoea of neonatal calves in two types of breeding - suckling and dairy calves - in France . Different agents causing neonatal diarrhoea, E . coli, rotavirus, coronavirus, Salmonella and Cryptosporidium were systematically researched in faeces . 1 . Suckling calves: In 40 livestock farms selected for diarrhoea, 311 calves 4 to 10 days old which had diarrhoea for less than 24h or no diarrhoea, were included in the study . A prophylaxis of neonatal diarrhoea had been carried out in 21 of the 40 livestock farms . On D0 (inclusion day), the mean age was 6 days, 82% presented a good initial general condition and 76.2% had a good appetite; 48.6% were diarrhoeic but 91.3% presented no sign of dehydration . Only 6.1% were infected by E . coli K99, 14.3% by rotavirus, 6.8% by coronavirus, 0.3% by Salmonella but 50% excreted C . parvum oocysts . This later percentage increases up to 84% and 86% by D3 and D7, respectively . We note that 16% of the 4-day-old calves on D0 are excreting oocysts and this percentage increases as a function of the age of the calf on D0 to reach 90% to 95% by the age of 8 days . 10 out of 12 dead calves excreted C . parvum oocysts . From D0 to D14 the other pathogen agents show a relative or a decreasing stability . 2 . Dairy calves: 382 calves which had diarrhoea for less than 24 h or no diarrhoea, aged 8 to 15 days coming from six industrial livestock farms were included in the study . On D0, 99% of the calves presented a good initial general condition, 99.7% had a good appetite and no calf was dehydrated . At this date (D0), 16.8% of the calves excreted cryptosporidia . This percentage increases up to 23% and 51.8% on D3 and D8, respectively, then decreases to 31.9% on D14 . The pressure of the other pathogenicagents remains relatively stable, excepted for rotavirus on D7 (from 9.9% on D0 to 27.2% on D7, then 12.6% on D14) which does not explain the concomitantpeak in diarrhoea because the infection by rotavirus on D7 is more frequent in non-diarrhoeic calves than in diarrhoeic calves . Our results show that Cryptosporidium prevalence is higher in suckling than in dairy calves and C . parvum constitutes actually in both cases the major aetiological agent of neonatal diarrhoea.

Dtsch Tierarztl Wochenschr, 1999 Aug, 106(8), 344 - 51
{Animals as sources of infections in humans--salmonellosis}; Meyer H; Foodborne infections/intoxications of men including salmonelloses increased as a whole in the last years . Some reasons for this development are discussed . From the 2,500 Salmonella serovars known at present only 10 to 15 are of epidemic importance, in the first place S . Typhimurium and S . Enteritidis . Mainly salmonella-contaminated foodstuffs from animals are sources of Salmonella infections in men . In this connection raw eggs and raw egg-containing food, as well as raw meat and meat products are of prime importance . Especially endangered are humans whose mechanisms of infectious defence are not fully developed (infants, young children) or are impaired to some extent (elderly people, immunocompromised persons) . Salmonellosis control has to be carried out as a concerted action along the whole food chain, starting at animal farms and continuing with adequate methods at each stage of food production and processing, in trade, in restaurants and canteens up to private households . In connection with the health protection of consumers hygienic education of staff handling foodstuffs, as well as information of consumers are very important . Despite some deficiencies our knowledge is sufficient to work effectively in practice to improve the situation.

EMBO J, 1999 Sep 15, 18(18), 4926 - 34
Direct nucleation and bundling of actin by the SipC protein of invasive Salmonella; Hayward RD et al.; Salmonella causes severe gastroenteritis in humans, entering non-phagocytic cells to initiate intracellular replication . Bacterial engulfment occurs by macropinocytosis, which is dependent upon nucleation of host cell actin polymerization and condensation ('bundling') of actin filaments into cables . This is stimulated by contact-induced delivery of an array of bacterial effector proteins, including the four Sips (Salmonella invasion proteins) . Here we show in vitro that SipC bundles actin filaments independently of host cell components, a previously unknown pathogen activity . Bundling is directed by the SipC N-terminal domain, while additionally the C-terminal domain nucleates actin polymerization, an activity so far known only in eukaryotic proteins . The ability of SipC to cause actin condensation and cytoskeletal rearrangements was confirmed in vivo by microinjection into cultured cells, although as SipC associates with lipid bilayers it is possible that these activities are normally directed from the host cell membrane . The data suggest a novel mechanism by which a pathogen directly modulates the cytoskeletal architecture of mammalian target cells.

Epidemiol Infect, 1999 Aug, 123(1), 37 - 46
Application of ribotyping and IS200 fingerprinting to distinguish the five Salmonella serotype O6,7:c:1,5 groups: Choleraesuis sensu stricto, Choleraesuis var . Kunzendorf, Choleraesuis var . Decatur, Paratyphi C, and Typhisuis; Uzzau S et al.; Sixty-seven strains of the five described Salmonella serotypes having antigens 6,7:c:1,5, that is S . enterica serotype Choleraesuis sensu stricto, Choleraesuis var . Kunzendorf, Choleraesuis var . Decatur, Paratyphi C, and Typhisuis, were examined for 16S rrn profile ribotype, presence of IS200 and phenotypic characters, including rate of change of flagellar-antigen phase and nutritional character . Choleraesuis sensu stricto and its Kunzendorf variant had related but distinct ribotypes . Therefore, ribotyping appears to be a suitable method for differentiating Choleraesuis non-Kunzendorf from Choleraesuis var . Kunzendorf . Some strains of Paratyphi C had 16S profiles that resembled that of Choleraesuis non-Kunzendorf, while others resembled that of Choleraesuis var . Kunzendorf . The Typhisuis profiles were like those of Choleraesuis non-Kunzendorf, while the Choleraesuis var . Decatur profiles were unlike those of any of the other four groups . Furthermore, IS200 fingerprinting discriminated between Choleraesuis var . Decatur and the other strains with antigenic formula O6,7:c:1,5, and comparison of IS200 patterns showed a high degree of genetic divergence within Choleraesuis var . Decatur . Our findings show that ribotyping and IS200 fingerprinting, combined with classical microbiological methods, distinguish the groups Choleraesuis non-Kunzendorf, Choleraesuis var . Kunzendorf, Choleraesuis var . Decatur, Paratyphi C and Typhisuis.

Epidemiol Infect, 1999 Aug, 123(1), 31 - 5
An international outbreak of Salmonella enteritidis associated with lasagne; lessons on the need for cross-national co-operation in investigating food-borne outbreaks; Nylen G et al.; We investigated an outbreak of Salmonella enteritidis involving at least 19 British tourists returning from one hotel in another European country . A retrospective cohort study of 47 hotel guests identified lasagne as the most likely vehicle of transmission (RR 11.5; 95% CI 3.0-44.1; P < 0.0001) . However, difficulties in information exchange and lack of formal mechanisms to agree on the aims of the cross-national investigation hampered efficient management of the outbreak . The factors leading to contamination of the food vehicle were not identified and therefore specific action to prevent reoccurrence could not be taken . There is need to develop protocols for cross-national investigations of outbreaks in Europe which should include specifying objectives, roles and responsibilities of investigators and control agencies, with formal reporting of the outcome of the investigation.

Kansenshogaku Zasshi, 1999 Aug, 73(8), 758 - 65
{Recovery and its evaluation of Shigella bacilli or Salmonella from healthy food handlers in Tokyo (1961-1997)}; Yamada S et al.; Since 1961, recovery of Shigella bachilli from healthy food handlers in Tokyo has been carrying out, and detection of Salmonella carriers has also been adding from 1980 . Recovery rate of Shigella has decreased from 0.28% (589 cases) in 1961 to 0.01% (9 cases) in 1969, and 7 cases between 1971 and 1975 and only 3 carriers since 1976 have been detected . On the other hand, Salmonella has been detected from about 9,000 cases (0.07%) during 18 years . The isolates were typed into 150 serovars, in which the most frequent one was S . Enteritidis, following S . Litchfield, S . Thompson, S . Hadar, S . Typhimurium, S . Infantis, S . Tennessee, S . Montevideo, S . Agona and S . Braenderup . These serovars except S . Agona caused in 90% of 1,650 Salmonella food poisoning outbreaks which had occurred between 1980 and 1996 . Recovery of S . Enteritidis from healthy subjects increased year by year since 1989, and this tendency was well consistent with the increase of food poisoning outbreak caused by this serovar . These results indicate that the recovery of carrier with enteropathogen from food handlars is significant as preventive measures or food hygiene.

Berl Munch Tierarztl Wochenschr, 1999 Aug, 112(8), 296 - 300
{Attempt to estimate the share of human Salmonella infections, which are attributable to Salmonella originating from swine}; Steinbach G et al.; On the basis of the data obtained in 1996 and 1997 in Germany on the frequency of detection of Salmonella and also of single Salmonella serovars in foods and infected humans, attempts were made to assess the relevance of Salmonella from swine as a source of human infection . Four assumptions considered as reasonable were made concerning the development of human salmonellosis . On the basis of these assumptions, a model for the estimation of the share of human Salmonella infections attributable to the swine population is proposed . According to this, ca . 20% of human cases of salmonellosis have been caused by Salmonella originating from swine.

J Biotechnol, 1999 Aug 20, 73(2-3), 185 - 94
Molecular characterization and module composition of P22-related Salmonella phage genomes; Schicklmaier P et al.; Genomes of newly isolated Salmonella phages were analysed by comparison of their EcoRI restriction patterns and by hybridization . Characteristic hybridization probes from reference phages P22, ES18 and E . coli phage lambda were chosen . Four probes selected from the lysis region examined the dispersal of the lambdoid lysis genes . Other probes characterized were the replication genes and part of the structural genes . The complex immunity region was investigated by means of hybridization as well as biological tests . The results showed the relationship of the isolated phages to the P22 branch of the lambdoid phages and revealed their modular genome organization consisting of different proportions of P22-related sequences . DNA restriction patterns of phages released from Salmonella strains sampled in limited geographical areas were significantly less heterogeneous than those of phages released from the worldwide sampled SARA collection . The use of prophage restriction patterns as a tool for the typing of Salmonellae to support the epidemiologic classification of pathogenic strains is discussed.

J Bacteriol, 1999 Sep, 181(18), 5808 - 13
Effect of hook subunit concentration on assembly and control of length of the flagellar hook of Salmonella; Muramoto K et al.; The flagellar hook of Salmonella is a filamentous polymer made up of subunits of the protein FlgE . Hook assembly is terminated when the length reaches about 55 nm . After our recent study of the effect of cellular levels of the hook length control protein FliK, we have now analyzed the effect of cellular levels of FlgE itself . When FlgE was overproduced in a wild-type strain, a fliC (flagellin) mutant, or a fliD (hook-associated protein 2 {HAP2}, filament capping protein) mutant, the hooks remained at the wild-type length . In a fliK (hook length control protein) mutant, which produces long hooks (polyhooks), the overproduction of FlgE resulted in extraordinarily long hooks (superpolyhooks) . In a flgK (HAP1, first hook-filament junction protein) mutant or a flgL (HAP3, second hook-filament junction protein) mutant, the overproduction of FlgE also resulted in longer than normal hooks . Thus, at elevated hook protein levels not only FliK but also FlgK and FlgL are necessary for the proper termination of hook elongation . When FlgE was severely underproduced, basal bodies without hooks were often observed . However, those hooks that were seen were of wild-type length, demonstrating that FlgE underproduction decreases the probability of the initiation of hook assembly but not the extent of hook elongation.

J Med Microbiol, 1999 Sep, 48(9), 801 - 10
Invasiveness of Salmonella serotypes Typhimurium, Choleraesuis and Dublin for rabbit terminal ileum in vitro; Bolton AJ et al.; Ten recent clinical isolates of Salmonella serotype Typhimurium from man that were tested for their invasiveness in rabbit ileal explants in vitro, were compared with Typhimurium strain TML, a well-characterised invasive strain isolated from a case of human gastro-enteritis . Nine of the 10 strains showed invasiveness that was comparable to that of strain TML . One isolate (GM3) was apparently substantially less invasive; electron microscopy showed this strain to be histotoxic - the probable reason for its reduced recovery from ileal mucosa and thus apparent 'low' invasiveness . Salmonella serotype Choleraesuis strain A50, isolated from a case of systemic salmonellosis in pigs, and serotype Dublin strain 3246, isolated from a case of systemic salmonellosis in calves, were also examined . Dublin strain 3246, when grown at 37 degrees C and used immediately in the invasion assay, damaged the mucosa in a manner similar to that of Typhimurium strain GM3, whereas Dublin strain 3246 grown at 37 degrees C and stored overnight at 4 degrees C did not . This was reflected in an apparently lower invasiveness of freshly grown organisms compared with that of organisms stored at 4 degrees C . In contrast, the histotoxicity of Typhimurium strain GM3 was not affected by storage at 4 degrees C . When stored at 4 degrees C, the levels of invasiveness of Choleraesuis strain A50 and Dublin strain 3246 were not significantly different from each other or from Typhimurium strain TML.

Dtsch Tierarztl Wochenschr, 1999 Jul, 106(7), 282 - 8
{Salmonella infections in swine herds--epidemiology and importance for human diseases}; Steinbach G et al.; Based on pertinent literature and research work performed by the authors, a report is presented on the presence of salmonellas in swine herds and the importance of these organisms as agents of disease in swine and source of infection for human salmonellosis . The share among human cases of salmonellosis which are caused by salmonellas originating from swine is estimated at ca . 20% . It has to be assumed that a very large proportion of swine herds is contaminated by Salmonella . Salmonellas may be introduced through infected pigs (parent animals, pigs from other herds added to the herd) or carriers among other animal species (e.g . rodent pests, birds) as well as by feeding stuffs with primary or secondary contamination . So far, the individual importance of the various routes cannot be reliably assessed . It appears that the level of Salmonella prevalence within a herd essentially depends on the hygienic conditions, the mode of keeping and the management of the animals . Serological examinations of meat juice permit conclusions as to the level of Salmonella contamination in slaughtered pigs . The results can thus be used for programmes to reduce the introduction of salmonellas into the food chain.

J Biol Chem, 1999 Sep 17, 274(38), 27185 - 90
Molecular characterization of the PmrA regulon; Wosten MM et al.; The two-component system PmrA/PmrB of Salmonella enterica controls expression of several loci including those mediating modifications in the lipopolysaccharide that result in polymyxin resistance . To gain insight in the regulation of polymyxin resistance, we mapped the transcription start sites of the PmrA-regulated genes pmrC, pmrG, pbgPE, and ugd and identified a conserved sequence in the promoter region of the first three genes . His-tagged PmrA protein could gel shift DNA fragments containing the promoters of the pmrC, pmrG, and pbgPE genes but not the udg promoter . DNase I footprinting analysis of the pmrC, pmrG, and pbgPE promoters indicate that phosphorylated as well as unphosphorylated PmrA bind to a 16-base pair imperfect inverted repeat sequence (5'-TTAAKTTCTTAAKGTT-3'), which is found 40, 80, and 38 nucleotides upstream from the transcription start sites of the pmrC, pmrG, and pbgPE genes, respectively . Our data suggest that a PmrA dimer activates transcription of the divergent pmrG and pbgPE promoters by binding to a single site in the pmrG-pbgPE intergenic region and that the ugd gene is regulated by the PmrA/PmrB system only indirectly.

Microbiol Immunol, 1999, 43(6), 535 - 42
Protective efficacy and immunogenicity of Vi-porin conjugate against Salmonella typhi; Singh M et al.; A conjugate vaccine against Salmonella typhi was prepared by covalently binding capsular polysaccharide (Vi) with porin, both isolated from S . typhi . First, Vi and porins were extracted . The Vi was purified from S . typhi Ty2 . The purified Vi conformed to the requirements of the World Health Organization . Porins were purified from S . typhi 0901 . The Vi was bound to the porins by a heterobifunctional cross-linking reagent, N-succinimidyl-3-(2-pyridyl dithio)-propionate (SPDP) . After preparing the Vi-porin conjugate, its protective ability and immunogenicity were studied in mice following systemic immunization . The results showed that the conjugate is 6.5-fold more protective than Vi alone against S . typhi . The mice immunized with conjugate elicited higher anti-Vi antibody (IgG) levels (P < 0.01) than the mice immunized with Vi alone . Anti-porin antibodies were also induced by the conjugate . To study the mucosal immune responses, secretory IgA (sIgA) in the intestinal fluid was measured . Conjugate-immunized mice showed the induction of sIgA as compared to Vi alone . The results showed that when Vi is bound to porins, both isolated from same organism, the resultant conjugate induced both systemic and mucosal immune responses and provided better protection against S . typhi than Vi alone.

J Infect Dis, 1999 Oct, 180(4), 1361 - 4
An outbreak of Salmonella serogroup Saphra due to cantaloupes from Mexico; Mohle-Boetani JC et al.; An outbreak of Salmonella serogroup Saphra (S . saphra) infections was studied by laboratory-based surveillance, case-control and trace-back studies, and a survey of cantaloupe preparation practices . Twenty-four patients with S . saphra infections had illness onsets between 23 February and 15 May 1997; 75% were </=6 years old; 23% were hospitalized . Case patients were more likely than controls to have consumed cantaloupe (88% vs . 45%; matched odds ratio {MOR}, 15 . 5; 95% confidence interval {CI}, 1.7-139) and precut cantaloupe (59% vs . 19%; MOR, 14.5; 95% CI, 1.6-128) . The trace-back study identified 1 growing region in Mexico as the source of cantaloupes for 95% of the patients who ate cantaloupes . Only 17% of case patients washed cantaloupes before cutting them . This outbreak is another example of gastrointestinal disease in the United States associated with imported contaminated produce . Consumers and retailers should wash cantaloupes before cutting them; there should be international efforts to ensure food safety.

J Infect Dis, 1999 Oct, 180(4), 1214 - 9
An increase in sporadic and outbreak-associated Salmonella enteritidis infections in Wisconsin: the role of eggs; Trepka MJ et al.; In Wisconsin, reported Salmonella enterica serotype enteritidis (SE) infections during 1997 more than doubled compared with the previous 9 years . A case-control study was conducted to determine risk factors for sporadic infections, and results of outbreak investigations were reviewed . Eating raw eggs (matched odds ratio {MOR}=14.5; 95% confidence interval {CI}, 1.7-591.6), eating raw or undercooked eggs (MOR=5.8; 95% CI, 1.3-28.0), eating any eggs (MOR=4.2; 95% CI, 1.2-16.2), and dining at a restaurant (MOR=4.7; 95% CI, 1.4-18.4) were associated with infection in the case-control study . For 3 of the 8 outbreaks, a probable source was identified, in each instance, foods containing eggs . Human infections decreased after eggs were diverted from implicated flocks . This epidemic demonstrates the continuing need for quality assurance on egg farms and enhanced education of consumers and commercial food preparers regarding safe handling of eggs.

Mutat Res, 1999 Jul 21, 444(1), 25 - 39
Cytotoxic and genotoxic effects of energetic compounds on bacterial and mammalian cells in vitro; Lachance B et al.; The mutagenicity and toxicity of energetic compounds such as 2,4, 6-trinitrotoluene (TNT), 1,3,5-trinitrobenzene (TNB), hexahydro-1,3, 5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3, 5,7-tetrazocine (HMX), and of amino/nitro derivatives of toluene were investigated in vitro . Mutagenicity was evaluated with the Salmonella fluctuation test (FT) and the V79 Chinese hamster lung cell mutagenicity assay . Cytotoxicity was evaluated using V79 and TK6 human lymphoblastic cells . For the TK6 and V79 assays, TNB and 2, 4,6-triaminotoluene were more toxic than TNT, whereas RDX and HMX were without effect at their maximal aqueous solubility limits . The primary TNT metabolites (2-amino-4,6-dinitrotoluene, 4-amino-2, 6-dinitrotoluene, 2,4-diamino-6-nitrotoluene and 2, 6-diamino-4-nitrotoluene) were generally less cytotoxic than the parent compound . The FT results indicated that TNB, TNT and all the tested primary TNT metabolites were mutagenic . Except for the cases of 4-amino-2,6-dinitrotoluene and 2,4-diamino-6-nitrotoluene in the TA98 strain, addition of rat liver S9 resulted in either no effect, or decreased activity . None of the tested compounds were mutagenic for the V79 mammalian cells with or without S9 metabolic activation . Thus, the FT assay was more sensitive to the genotoxic effects of energetic compounds than was the V79 test, suggesting that the FT might be a better screening tool for the presence of these explosives . The lack of mutagenicity of pure substances for V79 cells under the conditions used in this study does not preclude that genotoxicity could actually exist in other mammalian cells . In view of earlier reports and this study, mutagenicity testing of environmental samples should be considered as part of the hazard assessment of sites contaminated by TNT and related products.

Mutat Res, 1999 Jul 21, 444(1), 17 - 23
Mutagenic and genotoxic effects of theophylline and theobromine in Salmonella assay and in vivo sister chromatid exchanges in bone marrow cells of mice; Giri AK et al.; The mutagenic and genotoxic effects of two methylxanthines, theophylline (TH) and theobromine (TB), were assessed in the Ames mutagenicity assay (in strains TA97a, TA100, TA102 and TA104) and in vivo sister chromatid exchanges (SCEs) in bone marrow cells of mice . These are the two most commonly used nervous system stimulators throughout the world . TH is used in the long-term treatment of asthma . Bacterial mutagenicity assay showed very weak mutagenic effects of both drugs in Salmonella strains TA102 and TA104 only in certain concentrations when S9 was added to it . No mutagenic effects were observed in any other strains used in this assay either with or without metabolic activation . But results of in vivo SCE assay indicate that these two drugs can induce significant SCE in bone marrow cells of mice.

Mutat Res, 1999 Jul 21, 444(1), 7 - 16
Mutagenicity of commercial Monascus fermentation products and the role of citrinin contamination; Sabater-Vilar M et al.; Pigments produced as secondary metabolites by various isolates of moulds belonging to the genus Monascus have been used traditionally as colorants in Oriental food . Modern food industry has rediscovered these moulds as promising source for natural colorants . However, recent studies evidence that one of the secondary metabolites produced by Monascus is identical in structure to the mycotoxin citrinin . Thus, a sensitive HPLC method was developed to analyse these food colorants for contamination with citrinin . The mycotoxin could be detected in all the commercial Monascus samples at concentrations varying between 0.2 to 17.1 microg/g . In addition, the mutagenicity of commercial Monascus samples applying Salmonella-microsome assay and Salmonella-hepatocyte-assay was investigated and compared to the results obtained with citrinin . Citrinin and two Monascus extracts induced a positive dose depending mutagenic response in the Salmonella-hepatocyte-assay applying strain TA-98 . However, no mutagenicity could be detected in the Salmonella-microsome assay, neither with nor without S9-mix, for citrinin and Monascus extracts, applying TA-98, TA-100, TA-1535, TA-1538 and TA-97 . These findings provide further evidence that citrinin requires complex cellular biotransformation to exert mutagenicity.

Int J Food Microbiol, 1999 Aug 1, 49(1-2), 63 - 74
A predictive model for the non-thermal inactivation of Salmonella enteritidis in a food model system supplemented with a natural antimicrobial; Koutsoumanis K et al.; Home-made taramasalad, a traditional Greek appetizer, was inoculated with Salmonella enteritidis supplemented with different concentrations of oregano essential oil (0.0, 0.5, 1.0, 2.0% v/w) and stored at different temperatures (5, 10, 15, 20 degrees C) . The product's pH was adjusted from 4.3 to 5.3 with lemon juice . At each combination of the environmental factors, the bacterial counts were modelled as a function of time in order to estimate the kinetic parameters of the pathogen . For comparison, two different models were used . A reduction of Salmonella enteritidis was observed in all cases and its death rate depended on the pH, the storage temperature and the essential oil concentration . Death responses as a function of pH, storage temperature and concentration of oregano essential oil were described using a quadratic function which was then used to predict the death of Salmonella enteritidis in home-made taramasalad of different compositions.

Lancet, 1999 Aug 28, 354(9180), 734 - 7
Typhoid fever in children aged less than 5 years; Sinha A et al.; BACKGROUND: Calculation of the incidence of typhoid fever during preschool years is important to define the optimum age of immunisation and the choice of vaccines for public-health programmes in developing countries . Hospital-based studies have suggested that children younger than 5 years do not need vaccination against typhoid fever, but this view needs to be re-examined in community-based longitudinal studies . We undertook a prospective follow-up study of residents of a low-income urban area of Delhi, India, with active surveillance for case detection . METHODS: A baseline census was undertaken in 1995 . Between Nov 1, 1995, and Oct 31, 1996, we visited 8172 residents of 1820 households in Kalkaji, Delhi, twice weekly to detect febrile cases . Blood samples were obtained from febrile patients, and those who tested positive for Salmonella typhi were treated with ciprofloxacin . FINDINGS: 63 culture-positive typhoid fever cases were detected . Of these, 28 (44%) were in children aged under 5 years . The incidence rate of typhoid per 1000 person-years was 27.3 at age under 5 years, 11.7 at 5-19 years, and 1.1 between 19 and 40 years . The difference in the incidence of typhoid fever between those under 5 years and those aged 5-19 years (15.6 per 1000 person-years {95% CI 4.7-26.5}), and those aged 19-40 years (26.2 {16.0-36.3}) was significant (p<0.001 for both) . The difference between the incidence of typhoid at 5-19 years and the incidence at 19-40 years was also significant (10.6 {6.3-14.8}, p<0.001) . Morbidity in those under 5 and in older people was similar in terms of duration of fever, signs and symptoms, and need for hospital admission . INTERPRETATION: Our findings challenge the common view that typhoid fever is a disorder of school-age children and of adults . Typhoid is a common and significant cause of morbidity between 1 and 5 years of age . The optimum age of typhoid immunisation and the choice of vaccines needs to be reassessedPIP: This study was conducted to measure the incidence of typhoid fever among preschoolers . It was suggested that children aged 5 years do not need vaccination against typhoid fever . However, it is important to re-examine this view, particularly in infants and young children in the low-income urban area of Delhi, India, through active surveillance . Blood samples were obtained from febrile patients, and those who tested positive for Salmonella typhi were treated with ciprofloxacin . Findings revealed 63 culture-positive typhoid fever cases, about 44% of which were in children under 5 years of age . Morbidity in children under age 5 and in older people was similar in terms of duration of fever, signs and symptoms, and the need for hospital admission . The incidence of typhoid fever and the age distribution of the case varied between developing countries . Thus, the age patterns of typhoid fever observed in the urban study area may differ in rural areas within India or in other developing countries . A reevaluation of the optimum age and vaccine of choice is needed .

Mutagenesis, 1999 Sep, 14(5), 479 - 82
Induction of genetic damage in human lymphocytes and mutations in Salmonella by trihalomethanes: role of red blood cells and GSTT1-1 polymorphism; Landi S et al.; The brominated trihalomethanes (THMs) are mutagenic and carcinogenic disinfection by-products frequently found in chlorinated drinking water . They can be activated to mutagens by the product of the glutathione S-transferase-Theta (GSTT1++-1) gene in Salmonella RSJ100, which has been transfected with this gene . To evaluate this phenomenon in humans, we have examined the genotoxicity of a brominated THM, bromoform (BF), using the Comet assay in human whole blood cultures exposed in vitro . No differences were found in the comet tail length between cultures from GSTT1-1(+) versus GSTT1-1(-) individuals (1.67 +/- 0.40 and 0.74 +/- 0.54 microm/mM, respectively, P = 0.28) . The high variability was due to the relatively weak induction of comets by BF . Combining the data from both genotypic groups, the genotoxic potency of BF was 1.20 +/- 0.34 microm/mM (P = 0.003) . GSTT1-1 is expressed in red blood cells but not in the target cells (lymphocytes), and expression within the target cell (as in Salmonella RSJ100) may be necessary for enhanced mutagenesis in GSTT1-1(+) relative to GSTT1-1(-) cultures . To examine this, we exposed Salmonella RSJ100 and a control strain not expressing the gene (TPT100) to the most mutagenic brominated THM detected in Salmonella, dibromochloromethane (DBCM), either in the presence or absence of S9 or red blood cells from GSTT1-1(+) or GSTT1-1(-) individuals . S9 did not activate DBCM in the non-expressing strain TPT100, and it did not affect the ability of the expressing strain RSJ100 to activate DBCM . As with S9, red cells from either genotypic group were unable to activate DBCM in TPT100 . However, red cells (whole or lysed) from both genotypic groups completely repressed the ability of the expressing strain RSJ100 to activate DBCM to a mutagen . Such results suggest a model in which exposure to brominated THMs may pose an excess genotoxic risk in GSTT1-1(+) individuals to those organs and tissues that both express this gene and come into direct contact with the brominated THM, such as the colon . In contrast, those organs to which brominated THMs would be transported via the blood might be protected by erythrocytes . Such a proposal is reasonably consistent with the organ specificity of drinking water-associated cancer in humans, which shows slightly elevated risks for cancer of the colon and bladder but not of the liver.

Appl Environ Microbiol, 1999 Sep, 65(9), 4248 - 51
Variation in resistance to hydrostatic pressure among strains of food-borne pathogens; Alpas H et al.; Among food-borne pathogens, some strains could be resistant to hydrostatic pressure treatment . This information is necessary to establish processing parameters to ensure safety of pressure-pasteurized foods (N . Kalchayanand, A . Sikes, C . P . Dunne, and B . Ray, J . Food Prot . 61:425-431, 1998) . We studied variation in pressure resistance among strains of Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, and Salmonella species at two temperatures of pressurization . Early-stationary-phase cells in 1% peptone solution were pressurized at 345 MPa either for 5 min at 25 degrees C or for 5, 10, or 15 min at 50 degrees C . The viability loss (in log cycles) following pressurization at 25 degrees C ranged from 0.9 to 3.5 among nine L . monocytogenes strains, 0.7 to 7.8 among seven S . aureus strains, 2.8 to 5.6 among six E . coli O157:H7 strains, and 5.5 to 8.3 among six Salmonella strains . The results show that at 25 degrees C some strains of each species are more resistant to pressure than the others . However, when one resistant and one sensitive strain from each species were pressurized at 345 MPa and 50 degrees C, the population of all except the resistant S . aureus strain was reduced by more than 8 log cycles within 5 min . Viability loss of the resistant S . aureus strain was 6.3 log cycles even after 15 min of pressurization . This shows that strains of food-borne pathogens differ in resistance to hydrostatic pressure (345 MPa) at 25 degrees C, but this difference is greatly reduced at 50 degrees C . Pressurization at 50 degrees C, in place of 25 degrees C, will ensure greater safety of foods.

Toxicol Lett, 1999 Jul 30, 108(1), 27 - 35
In vitro and in vivo toxicological study of the Pterodon pubescens seed oil; Sabino KC et al.; The oil of Pterodon pubescens seeds (PpSO) is known for its cercaricidal and anti-inflammatory effects . Its anti-rheumatic activity was recently reported using mice with collagen II-induced arthritis treated with a hydroalcoholic extract of PpSO, mimicking the wine infusion used in popular medicine . In the present study, PpSO was tested for acute toxicity, mutagenic activity and cytotoxicity for human peripheral blood mononuclear cells (PBMNC) . PpSO was obtained after seed extraction with 100% ethanol and evaporation . Cytotoxicity was estimated using the tetrazolium salt reduction test (MTT assay) by PBMNC (2.5 x 10(5) cells/ml) after exposure to 0.07, 0.7 and 7 microg PpSO/ml for 24 and 48 h . In the mutagenesis assay, the Salmonella/mammalian microsome assay was employed with or without metabolization . Acute toxicity was studied on 30 (n = 10/group) male DBA1/J mice (20 +/- 2 g) after a single oral dose of 2, 4, and 8 g PpSO/kg b.w . The animals were observed for 24 h, anesthetized, sacrificed and autopsied . The organs were processed for histopathology by staining with hematoxylin-eosin . The IC50 of PpSO to PBMNC in RPMI 1640 supplemented with 5% fetal calf serum (FCS) was 2 and 1 microg PpSO/ml after 24 and 48 h, respectively . The mutagenic test performed with or without metabolic activation of PpSO did not show mutagenic activity for the concentrations tested (7 and 70 microg/ml) . Mouse mortality or significant signs of acute toxicity (ocular, cardiovascular, gastrointestinal, motor or respiratory signs) for the PpSO doses tested was not observed . The organs did not show any macroscopic alterations . Histopathologic analysis of the tissues also did not demonstrate any lesions . The present study provides data to classify PpSO as non-cytotoxic to PBMNC, non-mutagenic, and non-toxic after acute administration since the PpSO doses tested were extremely higher than those used by the population.

Vet Microbiol, 1999 Jul 1, 67(4), 263 - 75
Salmonella infections in finishing pigs in The Netherlands: bacteriological herd prevalence, serogroup and antibiotic resistance of isolates and risk factors for infection; van der Wolf PJ et al.; Salmonellae are wide spread in man and animals world wide and are of increasing significance as causative agents of foodborne diseases in man . The European Union, national authorities and the pig industry are therefore more and more interested in the Salmonella status of the pig population . The aim of this study was to estimate the bacteriological prevalence of Salmonella in finishing pig herds, the serogroup and the resistance to antibiotics of the isolated Salmonellae and a preliminary risk analysis of factors associated with infection . For this, 317 finishing pig herds were randomly selected from a database containing 1500 herds in the southern part of the Netherlands . In each herd 24 samples of fresh faeces were collected from two compartments with pigs close to market weight . Per compartment 12 samples of faeces were pooled into one pooled sample . Pooled samples were cultured in duplicate . Salmonella spp . were recovered from 71 out of 306 herds (23%) in which two compartments could be sampled . A total of 108 isolated Salmonella's were serotyped: 71 serogroup B, 3 serogroup C1, 6 serogroup C2, 22 serogroup D1, and 6 isolates neither serogroup B, C or D1 . Of a total of 115 Salmonella isolates tested, none were resistant to colistin, enrofloxacin, flumequin or gentamicin . Automated liquid feeding of by-products, and membership of an Integrated Quality Control (IQC) production group were associated with a decreased risk of infection, while use of trough feeding was associated with an increased risk of infection . It is necessary to test these presumed risk factors in intervention studies to evaluate their potency to reduce the Salmonella prevalence in finishing pigs and thereby reduce the risk of Salmonellosis in people consuming pork.

Am Fam Physician, 1999 Aug, 60(2), 499 - 503, 507
Reactive arthritis (Reiter's syndrome); Barth WF et al.; Reactive arthritis, also called Reiter's syndrome, is the most common type of inflammatory polyarthritis in young men . It is sometimes the first manifestation of human immunodeficiency virus infection . An HLA-B27 genotype is a predisposing factor in over two thirds of patients with reactive arthritis . The syndrome most frequently follows genitourinary infection with Chlamydia trachomatis, but other organisms have also been implicated . Treatment with doxycycline or its analogs sometimes shortens the course or aborts the onset of the arthritis . Reactive arthritis may also follow enteric infections with some strains of Salmonella or Shigella, but use of antibiotics in these patients has not been shown to be effective . Reactive arthritis should always be considered in young men who present with polyarthritis . Symptoms may persist for long periods and may, in some cases, cause long-term disability . Initial treatment consists of high doses of potent nonsteroidal anti-inflammatory drugs . Patients with large-joint involvement may also benefit from intra-articular corticosteroid injection.

J Food Prot, 1997 Jan, 60(1), 16 - 22
Attachment of Salmonella choleraesuis choleraesuis to beef muscle and adipose tissues; Bouttier S et al.; The attachment of Salmonella choleraesuis subsp . choleraesuis ATCC 15790 to beef muscle and adipose tissues was investigated . S . choleraesuis was found to adhere in higher numbers to muscle than to fat . The charge and the hydrophobicity of the surface of S . choleraesuis were evaluated by measurement of electrophoretic mobility, the contact angle with water, adhesion to hexadecane, and hydrophobic interaction chromatography . The overall negative charge of S . choleraesuis was masked by the high electrolyte concentration in the attachment medium (0.15 M phosphate-buffered saline) . This bacterium was shown to possess a hydrophilic surface . Electrostatic interactions do not affect the attachment of S . choleraesuis to both lean and fat tissue, and there was no evidence for a role of hydrophobic interactions . However, the attachment of S . choleraesuis was reduced by 90% after mechanical removal of the flagella or after treatment of the bacteria with specific antiflagella serum . This reduction was attributed to a loss of bacterial mobility leading to a reduction in the number of cells reaching the tissue during the period of contact . Treatment of the tissue with a concentrated suspension of flagella or treatment of the bacteria with antisomatic serum (OMD) did not reduce the attachment of S . choleraesuis to tissues, indicating an absence of specific attachment sites for flagella or antigen O on the beef tissue surface.

J Food Prot, 1997 Jan, 60(1), 10 - 5
Provision of lactose to molting hens enhances resistance to Salmonella enteritidis colonization; Corrier DE et al.; Older leghorn hens, more than 50 weeks of age, were divided into three groups designated 1, unmolted controls; 2, molted; or 3, molted treated with lactose . Forced molt was induced by 14 days of feed removal . Lactose was provided to the hens in group 3 as 2.5% (wt/vol) of the daily drinking water . Each hen in all groups was challenged orally with 10(5) Salmonella enteritidis (SE) cells on day 7 of feed removal . The study was repeated in three replicated trials . The concentrations of acetic, propionic, and total volatile fatty acids (VFA) in the cecal contents of the molted hens in groups 2 and 3 decreased significantly (P < 0.05) on days 6 and 14 of molt compared with the unmolted controls . Forced molt had no apparent effect on pH or on the oxidation-reduction potential of the ceca . Compared to the unmolted controls, SE cecal and spleen and liver colonization was significantly increased (P < 0.05) in the molted hens in group 2 . Compared to the molted hens in group 2, SE cecal and spleen and liver colonization was significantly decreased (P < 0.05) in two of three trials in the hens in group 3 provided with lactose . The results suggested that the increased susceptibility of molting hens to SE colonization may be associated with decreased fermentation and production of VFA by cecal bacteria or by a depletion of the number of VFA-producing bacteria present in the ceca . The results further suggest that providing lactose in the drinking water during molting may significantly enhance resistance to SE colonization.

J Food Prot, 1996 Mar, 59(3), 322 - 6
Cetylpyridinium chloride (CPC) treatment on poultry skin to reduce attached Salmonella; Kim JW et al.; Cetylpyridinium chloride (1-hexadecylpyridinium chloride, CPC) was evaluated for its effectiveness in removing or killing salmonellae attached to poultry skin . Two different treatment methods were used: (i) spraying 0.1% CPC solution at 15 degrees C or 50 degrees C against inoculated skin surface for I min at 138 kPa, and (ii) immersing inoculated skin surface in 0.1% CPC solution at room temperature for either 1 min, 1 min plus 2 min holding without CPC, or 3 min . After rinsing, cells on the skins were enumerated by conventional plating as well as direct counting from scanning electron microscopy (SEM) . Compared with controls, CPC spraying reduced the numbers of salmonellae by 0.9 to 1.7 log units (87 to 98%) assayed by the plating method (P < 0.05) . SEM gave results similar to plating . Generally 50 degrees C CPC spraying showed greater reduction than 15 degrees C CPC spraying; however, the differences were not always significant . Water spraying at either temperature did not show any reduction compared to nonsprayed skins . In the immersion test, significant differences also were noticed among the control and the three other CPC-immersed groups (P < 0.05) as assayed by plating, ranging from 1.0 to 1.6 log units, which were similar to the CPC spraying results . However, no difference was noticed among the three CPC-immersed groups . Direct counting from SEM was not a suitable method for recovering cells in CPC immersion tests because dead cells were still attached to the skin while retaining their intact morphology . On the basis of the amount of CPC used, immersion appears to be more cost-effective than spraying CPC on poultry skin.

J Food Prot, 1996 Mar, 59(3), 287 - 94
Consumer knowledge of foodborne microbial hazards and food-handling practices; Altekruse SF et al.; A national telephone survey was conducted of 1,620 randomly selected U.S . residents who spoke English, were at least 18 years old, and resided in households with kitchen facilities . Respondents were interviewed about their recognition of foodborne pathogens, foods at risk for transmitting infection, knowledge of safe food handling, and food-handling practices . One-third of the respondents who prepared meals reported unsafe food hygiene practices: e.g., they did not wash hands or take precautions to prevent cross-contamination from raw meat . Unsafe practices were reported more often by men, adults 18 to 29 years of age, and occasional food preparers than by women, persons 30 years old or older, and frequent food preparers . Respondents who identified a food vehicle for Salmonella spp . were more likely to report washing their hands and cleaning cutting boards after preparing raw meat and poultry . The results raise concerns about consumer food-handling practices . The influence of food safety training, food-handling experience, and age on food-handling practices should be studied further . Awareness of a food vehicle for Salmonella spp., for example, may indicate knowledge of the etiology of foodborne disease that promotes safe food handling . Understanding the factors associated with safe food handling will assist in development of effective safe-food instruction programs.

J Food Prot, 1996 Mar, 59(3), 238 - 43
Comparison of a microtitration plate ELISA with a standard cultural procedure for the detection of Salmonella spp . in chicken; Wyatt GM et al.; A rapid antibody-capture enzyme-linked immunosorbent assay (ELISA) detecting a wide range of Salmonella serotypes and employing only one culture stage was used to analyze the giblets and body cavity rinsings from frozen chickens . The results from the ELISA were compared with those obtained using a standard cultural procedure in current use in two laboratories, Norwich (N) and Ipswich (I), of the Public Health Laboratory Service (PHLS) in the UK . ELISAs were carried out on the same samples at each of two PHLS laboratories and at the Institute of Food Research with good agreement (94% and 90%) . When compared with the cultural method there was 80% and 70% agreement with the ELISA with the PHLS(N) and PHLS(I) samples . The ELISA appeared to have a false-positive rate of 17% (samples from PHLS(N)) but on reculture of the "negative" samples this rate fell to 7% . The false-negative rate for the ELISA was 26% (samples from PHLS(N)) which appeared to be due to insufficient growth of the Salmonella spp . in the single cultural step employed in the ELISA rather than lack of recognition by the antibodies . The problem of false negatives with the cultural method is also discussed . These results are comparable to previously published studies relating immunoassays and the conventional procedure for Salmonella detection when analyzing similar samples . Suggestions are made as to how further increases in ELISA efficiency might be brought about.

Commun Dis Public Health, 1999 Jan, 2(1), 66 - 7
Undercooked hens eggs remain a risk factor for sporadic Salmonella enteritidis infection; Hayes S et al.; The prevalence of salmonella contamination in hens' eggs remains high . A case control study of sporadic cases of Salmonella enteritidis infection in Wales in 1997 confirmed the association of infection with consumption of raw or lightly cooked eggs.

Commun Dis Public Health, 1999 Jan, 2(1), 32 - 4
Common source outbreak of salmonellosis in a food factory; Wilson D et al.; Seventy-three employees at a food processing factory employing 2700 staff reported vomiting, diarrhoea, or abdominal pain between 30 July and 3 August 1997 . Salmonella enteritidis phage type (PT) 4 was isolated from 47 symptomatic cases and five asymptomatic canteen staff . The epidemic curve suggested a point exposure to a common source: 60% of cases reported illness on 31 July . An uncooked dessert containing raw shell eggs was identified as a possible vehicle of infection . Caterers are reminded that pasteurised egg should be substituted for shell egg in dishes that are eaten raw or only lightly cooked.

Vaccine, 1999 Aug 6, 17(23-24), 2941 - 5
Impaired antibody response after immunization of HIV-infected individuals with the polysaccharide vaccine against Salmonella typhi (Typhim-Vi); Kroon FP et al.; Infections with Salmonella species, including Salmonella typhi, are more frequently observed in HIV-infected individuals than in healthy individuals . HIV-infected individuals were vaccinated with polysaccharide vaccine against Salmonella typhi (Typhim-Vi) which is assumed to be a T-cell-independent antigen . We found that the antibody response in patients with < 200 x 10(6)/l CD4+ T lymphocytes was significantly lower compared with patients with > or = 200 x 10(6)/l CD4+ T lymphocytes and healthy controls . The antibody response after vaccination with the polysaccharide salmonella Vi-antigen was correlated with the number of CD4+ T lymphocytes and therefore Typhim-Vi can be considered to be a T-cell-independent type 2 antigen . The results of this study indicate that after vaccination the proportion of HIV-infected individuals with protective antibody concentrations against Salmonella typhi will be lower than in healthy controls.

Int J Antimicrob Agents, 1999 Aug, 12(3), 257 - 62
Antimicrobial activity of spices; Arora DS et al.; Spices have been shown to possess medicinal value, in particular, antimicrobial activity . This study compares the sensitivity of some human pathogenic bacteria and yeasts to various spice extracts and commonly employed chemotherapeutic substances . Of the different spices tested only garlic and clove were found to possess antimicrobial activity . The bactericidal effect of garlic extract was apparent within 1 h of incubation and 93% killing of Staphylococcus epidermidis and Salmonella typhi was achieved within 3 h . Yeasts were totally killed in 1 h by garlic extract but in 5 h with clove . Some bacteria showing resistance to certain antibiotics were sensitive to extracts of both garlic and clove . Greater anti-candidal activity was shown by garlic than by nystatin . Spices might have a great potential to be used as antimicrobial agents.

Epidemiol Infect, 1999 Jun, 122(3), 497 - 504
Discrimination between endemic and feedborne Salmonella Infantis infection in cattle by molecular typing; Lindqvist N et al.; Salmonella enterica serovar Infantis is endemic in Finnish cattle . Feed contaminated with S . Infantis was distributed to cattle farms in May 1995 . Following increased sampling, S . Infantis was detected on 242 farms in 1995 . Molecular typing was used to differentiate the farms that were infected by the feed-related Infantis from those infected by other endemic strains . Twenty-three isolates from feed in 1995 and 413 from cattle (72 from 19924, 324 from 1995, 17 from 1996-7) were analysed . The feed-related Infantis was clonally related to the endemic infection by the ribotype, IS200-type and XbaI-profile . The feed isolates had a distinctive plasmid that appeared in pulsed-field gel electrophoresis as a 60 kb band when cleaved with XbaI or linearized by S1-nuclease . This plasmid appeared in cattle only since the outbreak and seemed stable on the follow-up farms . In addition to contact farms, the feedborne strain was found on 19% of the farms infected with S . Infantis in 1995 but not having bought suspected feedstuffs, possibly as secondary infections.

Epidemiol Infect, 1999 Jun, 122(3), 395 - 402
Virulence of Salmonella enterica serotype Enteritidis aflagellate and afimbriate mutants in a day-old chick model; Allen-Vercoe E et al.; Certain fimbriae and the flagellae of Salmonella enterica serovar Typhimurium have been shown to contribute to attachment and invasion of gut epithelium in the murine typhoid infection model and to contribute to pathogenesis in the chick . However, little is known of the role these organelles play in Enteritidis poultry infections and, to study this, day-old chicks were dosed orally in separate experiments with defined multiply afimbriate and/or aflagellate mutant strains of Enteritidis . The colonization and invasion characteristics of each mutant were compared with those of the isogenic wild type strain by the determination of the number of bacteria recovered from livers and spleens at known time points post infection . Compared with wild type Enteritidis, a mutant unable to express flagella but retaining the genetic potential to express fimbriae was recovered post mortem from livers and spleens in significantly reduced numbers compared to the isogenic wild-type at all time points post infection (P < 0.001) . Conversely, a flagellate but multiply afimbriate mutant (defective for the elaboration of five different fimbrial types) and a flagellate but non-motile 'paralysed' mutant were recovered from livers and spleens in similar numbers to the wild-type . The data suggested that Enteritidis flagella, but not fimbriae, played an important role in pathogenesis in the chick model and that the flagellar apparatus itself and not motility per se contributed significantly to this role.

Epidemiol Infect, 1999 Jun, 122(3), 385 - 93
Outbreaks of salmonellosis associated with eating uncooked tomatoes: implications for public health . The Investigation Team; Hedberg CW et al.; Laboratory-based surveillance of salmonella isolates serotyped at four state health departments (Illinois, Michigan, Minnesota and Wisconsin) led to the identification of multistate outbreaks of salmonella infections during 1990 (176 cases of S . javiana) and 1993 (100 cases of S . montevideo) . Community-based case-control studies and product traceback implicated consumption of tomatoes from a single South Carolina tomato packer (Packer A) MOR 16.0; 95% CI2.1, 120.6; P < 0.0001 in 1990 and again in 1993 (MOR 5.7; 95 % CI 1.5, 21.9; P = 0.01) as the likely vehicle . Contamination likely occurred at the packing shed, where field grown tomatoes were dumped into a common water bath . These outbreaks represent part of a growing trend of large geographically dispersed outbreaks caused by sporadic or low-level contamination of widely distributed food items . Controlling contamination of agricultural commodities that are also ready-to-eat foods, particularly fruits and vegetables, presents a major challenge to industry, regulators and public health officials.

Diagn Microbiol Infect Dis, 1999 Aug, 34(4), 321 - 3
Pleuro pulmonary infection with Salmonella group E; Nair D et al.; A patient was admitted with a history of cough, shortness of breath and fever . After investigations, he was found to have a left-sided pneumonia with pleural effusion . Culture of the patient's sputum, pleural fluid and blood revealed Salmonella senftenberg . The patient was started on antibiotics according to the sensitivity report and responded to therapy . The past history revealed attempt at suicide by the intake of corrosive acid, which caused an esophageal stricture . The leak of gastric contents into the mediastinum lead to the infection of the pleural cavity and pneumonia.

Infect Immun, 1999 Sep, 67(9), 4628 - 36
Attenuation and immunogenicity of Deltacya Deltacrp derivatives of Salmonella choleraesuis in pigs; Kennedy MJ et al.; Six different isogenic Deltacya Deltacrp derivatives of a strain of Salmonella choleraesuis var . kunzendorf-chi3246 virulent for pigs were constructed by transposon-mediated deletion mutagenesis . These strains were evaluated for virulence and ability to elicit a protective immune response in young weaned pigs after oral administration and were compared to a commercially available vaccine which lacks the 50-kb virulence plasmid (vpl(-)) . These derivatives were Deltacya Deltacrp vpl(+), Deltacya Deltacrp vpl(-), Deltacya Delta(crp-cdt) vpl(+), Deltacya Delta(crp-cdt) vpl(-), Deltacya Deltacrp pmi-3834 vpl(+), and Deltacya Delta(crp-cdt) pmi-3834 . In experiments to evaluate safety, no significant adverse effects of any of the vaccine constructs were observed, except that two of the strains which carried the virulence plasmid (vpl(+)) caused a small, short-term elevation in maximum temperature compared to pretreatment temperature values . Orally immunized animals, except for those vaccinated with the Deltacya Deltacrp pmi-3834 vpl(+) strain or SC-54, developed significant serum antibody responses 21 days postvaccination as measured by enzyme-linked immunosorbent assay . No cell-mediated immune responses to heat-killed S . choleraesuis were noted at the same time point as measured with heat-killed bacteria as antigen in a lymphocyte proliferation assay . In an oral challenge exposure model with a highly virulent heterologous strain of S . choleraesuis, the Deltacya Deltacrp strains with deletions in pmi were not protective . As measured by morbidity scores, the responses to challenge of the pigs vaccinated with the other four Deltacya Deltacrp derivatives were significantly better than those of the nonvaccinated, challenged group . With the exception of temperature elevation and slight differences in diarrhea scores postchallenge, none of these strains differed significantly from each other in the other clinical parameters analyzed . While the commercial vaccine was protective by most of the parameters measured, it was not fully protective against challenge with virulent S . choleraesuis as judged by diarrhea scores and temperature elevation . Collectively, these data demonstrate that Deltacya Deltacrp derivatives, with or without the virulence plasmid but not with deletions in the pmi gene, are candidates for vaccines for protection against salmonellosis in pigs.

J Paediatr Child Health, 1999 Aug, 35(4), 379 - 82
Salmonella meningitis and its complications in infants; Lee WS et al.; OBJECTIVE: To review the presenting features, complications and outcome of infants with Salmonella meningitis . METHODOLOGY: Retrospective review of all cultures of cerebrospinal fluid positive for bacteria in children below 12 years of age, processed at the Department of Medical Microbiology, University of Malaya Medical Centre, Kuala Lumpur from 1973 to 1997 . Records of all cases positive for Salmonella species were retrieved and studied . RESULTS: Thirteen infants aged 3 days to 9 months with Salmonella meningitis were included . The median age of onset of symptoms was 4 months . The clinical and laboratory features were similar to other causes of bacterial meningitis . Salmonella enteritidis was the commonest serotype isolated . Nine infants developed fits, six of which were difficult to control . Other complications noted were hydrocephalus (five), subdural effusions (four), empyema (three), ventriculitis (two), intracranial haemorrhage and cerebral abscess (one each) . The use of ampicillin and/or chloramphenicol and inadequate duration of therapy resulted in recrudescence or relapse in five infants . The overall mortality was 18% . The presence of empyema, intracerebral abscess, ventriculitis, hydrocephalus, and intracranial haemorrhage were associated with adverse neurodevelopmental sequelae or death . More than half of those who survived had normal long-term outcome . CONCLUSION: Infants who developed neurological complications as a result of Salmonella meningitis had significant mortality and adverse long-term neurodevelopment outcome.

Infect Immun, 1999 Sep, 67(9), 4499 - 509
Invasive ability of an Escherichia coli strain isolated from the ileal mucosa of a patient with Crohn's disease; Boudeau J et al.; Crohn's disease (CD) is an inflammatory bowel disease in which Escherichia coli strains have been suspected of being involved . We demonstrated previously that ileal lesions of CD are colonized by E . coli strains able to adhere to intestinal Caco-2 cells but devoid of the virulence genes so far described in the pathogenic E . coli strains involved in gastrointestinal infections . In the present study we compared the invasive ability of one of these strains isolated from an ileal biopsy of a patient with CD, strain LF82, with that of reference enteroinvasive (EIEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), enteraggregative (EAggEC), enterohemorrhagic (EHEC), and diffusely adhering (DAEC) E . coli strains . Gentamicin protection assays showed that E . coli LF82 was able to efficiently invade HEp-2 cells . Its invasive level was not significantly different from that of EIEC and EPEC strains (P > 0.5) but significantly higher than that of ETEC (P < 0.03), EHEC (P < 0 . 005), EAggEC (P < 0.004) and DAEC (P < 0.02) strains . Strain LF82 also demonstrated efficient ability to invade intestinal epithelial cultured Caco-2, Intestine-407, and HCT-8 cells . Electron microscopy examination of infected HEp-2 cells revealed the presence of numerous intracellular bacteria located in vacuoles or free in the host cell cytoplasm . In addition, the interaction of strain LF82 with epithelial cells was associated with the elongation of microvillar extensions that extruded from the host cell membranes and engulfed the bacteria . This internalization mechanism strongly resembles Salmonella- or Shigella-induced macropinocytosis . The use of cytochalasin D and colchicine showed that the uptake of strain LF82 by HEp-2 cells was mediated by both an actin microfilament-dependent mechanism and microtubule involvement . In addition, strain LF82 survived for at least 24 h in HEp-2 and Intestine-407 cells and efficiently replicated intracellularly in HEp-2 cells . PCR and hybridization experiments did not reveal the presence of any of the genetic determinants encoding EIEC, EPEC, or ETEC proteins involved in bacterial invasion . Thus, these findings show that LF82, which colonized the ileal mucosa of a patient with CD, is a true invasive E . coli strain and suggest the existence of a new potentially pathogenic group of E . coli, which we propose be designated adherent-invasive E . coli.

Infect Immun, 1999 Sep, 67(9), 4360 - 6
Intranasal administration of synthetic recombinant peptide-based vaccine protects mice from infection by Schistosoma mansoni; Ben-Yedidia T et al.; Schistosomiasis is the cause of a chronic debilitating disease which accounts for significant mortality and morbidity every year, especially in tropical and subtropical areas . An epitope derived from the protective surface protein 9B-Ag of Schistosoma mansoni, designated 9B peptide-1, was previously showed to be protective in mice when conjugated to bovine serum albumin and administered subcutaneously in complete Freund's adjuvant . In this work, this protective peptide was expressed in the flagellin of a Salmonella vaccine strain, and the isolated recombinant flagella were used for immunization of mice . Since during the invasion of the parasite into the host the schistosomula migrate first to the lungs, the intranasal route of administration was employed in order to halt the parasite at an early stage of the infection . Such intranasal immunization with this peptide expressed in flagellin, without the addition of adjuvants, resulted in a significant humoral response and also led to protection against challenge infection, manifested as a reduction of the worm burden by an average of 42%.

J Food Prot, 1999 Aug, 62(8), 940 - 3
Inhibition of food-related pathogenic bacteria by god-transformed Penicillium nalgiovense strains; Geisen R; Two strains of Penicillium nalgiovense, which carried the god gene of Aspergillus niger and had increased glucose oxidase (GOD) activity compared with the wild-type strain, were tested for their ability to suppress the growth of certain food-related pathogenic bacteria . In contrast to the wild type, which showed no antibacterial effect when grown in mixed culture with different bacteria, the two transformed strains were highly antagonistic . The strain that expressed higher amounts of GOD in general had higher inhibitory activity . Both strains showed antibacterial activity against Listeria monocytogenes, Salmonella Enteritidis, and Staphylococcus aureus . The inhibitory activity was dependent on the glucose concentration in the medium . S . aureus was completely inhibited at 1% glucose in the presence of the higher GOD-producing transformant . In contrast, if arabinose was used as a carbon source, no inhibition occurred . If catalase was added to the medium, the inhibitory activity of the transformants was completely inactivated, indicating that the hydrogen peroxide produced was responsible for the antibacterial activity of the transformants.

J Food Prot, 1999 Aug, 62(8), 850 - 6
Behavior of enterohemorrhagic Escherichia coli O157:H7 on alfalfa sprouts during the sprouting process as influenced by treatments with various chemicals; Taormina PJ et al.; The behavior of Escherichia coli O157:H7 on alfalfa seeds subjected to conditions similar to those used commercially to grow and market sprouts as it is affected by applications of NaOCl, Ca(OCl)2, acidified NaClO2, acidified ClO2, Na3PO4, Vegi-Clean, Tsunami, Vortexx, or H2O2 at various stages of the sprouting process was determined . Application of 2,000 ppm of NaOCl, 200 and 2,000 ppm of Ca(OCl)2, 500 ppm of acidified ClO2, 10,000 ppm of Vegi-Clean, 80 ppm of Tsunami, or 40 and 80 ppm of Vortexx to germinated seeds significantly reduced the population of E . coli O157:H7 . With the exception of acidified NaOCl2 at 1,200 ppm, spray applications of these chemicals did not significantly reduce populations or control the growth of E . coli O157:H7 on alfalfa sprouts during the sprouting process . Populations of E . coli on alfalfa sprouts peaked at 6 to 7 log10 CFU/g 48 h after initiation of the sprouting process and remained stable despite further spraying with chemicals . The population of E . coli O157:H7 on sprouts as they entered cold storage at 9 +/- 2 degrees C remained essentially unchanged for up to 6 days . None of the chemical treatments evaluated was able to eliminate or satisfactorily reduce E . coli O157:H7 on alfalfa seeds and sprouts . Observations on the ability of E . coli O157:H7 to grow during production of alfalfa sprouts not subjected to chemical treatments are similar to those from a previous study in our laboratory on the behavior of Salmonella Stanley . Our results do not reveal a chemical treatment method to eliminate the pathogen from alfalfa sprouts . We have demonstrated that currently recommended procedures for sanitizing alfalfa seeds fail to eliminate E . coli O157:H7 and that the pathogen can grow to populations exceeding 7 1og10 CFU/g of sprouts produced using techniques not dissimilar to those used in the sprout industry.

South Med J, 1999 Aug, 92(8), 799 - 801
Clinical presentation and treatment of a Salmonella bredeney epidemic in Shelby County, Alabama; Jahraus CD et al.; BACKGROUND: Numerous residents of Shelby County, Alabama, were infected with Salmonella when a restaurant unknowingly served food tainted with the bacterium . Because of the similarity in symptoms caused by other gastrointestinal pathogens and the variability in time of presentation, an outbreak such as this could be confused with one of another pathogenic origin . The pathogen identified, Salmonella bredeney, is a particularly rare cause of food poisoning . It makes up only 0.1% of the Salmonella isolates identified by the Centers for Disease Control and Prevention (CDC) each year . METHODS: We analyzed patient presentations through chart review and combined this information with that obtained from the state laboratories in Montgomery and the Shelby County Health Department . RESULTS: Symptoms were mostly gastrointestinal and ranged greatly in severity . The total number of patients affected in this incident exceeded 170, making it the largest epidemic of its kind in the recent history of Alabama . CONCLUSIONS: The outbreak in Shelby County was caused by an exceedingly rare species of Salmonella . At this time, it is the only outbreak of S bredeney reported in MEDLINE-accessible literature since 1983.

J Biol Chem, 1999 Aug 27, 274(35), 25069 - 77
Characterization of dTDP-4-dehydrorhamnose 3,5-epimerase and dTDP-4-dehydrorhamnose reductase, required for dTDP-L-rhamnose biosynthesis in Salmonella enterica serovar Typhimurium LT2; Graninger M et al.; The thymidine diphosphate-L-rhamnose biosynthesis pathway is required for assembly of surface glycoconjugates in a growing list of bacterial pathogens, making this pathway a potential therapeutic target . However, the terminal reactions have not been characterized . To complete assignment of the reactions, the four enzymes (RmlABCD) that constitute the pathway in Salmonella enterica serovar Typhimurium LT2 were overexpressed . The purified RmlC and D enzymes together catalyze the terminal two steps involving NAD(P)H-dependent formation of dTDP-L-rhamnose from dTDP-6-deoxy-D-xylo-4-hexulose . RmlC was assigned as the thymidine diphosphate-4-dehydrorhamnose 3,5-epimerase by showing its activity to be NAD(P)H-independent . Spectrofluorometric and radiolabeling experiments were used to demonstrate the ability of RmlC to catalyze the formation of dTDP-6-deoxy-L-lyxo-4-hexulose from dTDP-6-deoxy-D-xylo-4-hexulose . Under reaction conditions, RmlC converted approximately 3% of its substrate to product . RmlD was unequivocally identified as the thymidine diphosphate-4-dehydrorhamnose reductase . The reductase property of RmlD was shown by equilibrium analysis and its ability to enable efficient biosynthesis of dTDP-L-rhamnose, even in the presence of low amounts of dTDP-6-deoxy-L-lyxo-4-hexulose . Comparison of 23 known and predicted RmlD sequences identified several conserved amino acid residues, especially the serine-tyrosine-lysine catalytic triad, characteristic for members of the reductase/epimerase/dehydrogenase protein superfamily . In conclusion, RmlD is a novel member of this protein superfamily.

Microb Pathog, 1999 Sep, 27(3), 155 - 71
Role of Salmonella enterotoxin in overall virulence of the organism; Chopra AK et al.; In this study, the Salmonella enterotoxin gene (stn) was mutated by marker exchange mutagenesis, and the overall virulence of the organism was evaluated . Salmonella marker exchange mutants evoked significantly less fluid secretion in mouse intestinal loops compared to that seen with wild-type S . typhimurium . Salmonella mutants were as invasive as wild-type bacteria for HeLa cells; however, their capacity to cause destruction of the intestinal mucosa was impaired, when compared with wild-type bacteria by electron microscopy . Upon oral challenge of mice, the LD(50)of the Salmonella mutants was greater than that for the wild-type bacteria . The fluid secretory potential, as well as a reduction in the LD(50)of these mutants was restored when the mutated stn gene was replaced by the native stn gene sequence . These mutations had no effect on the aerobic growth of these bacteria in minimal or complete medium; anaerobic growth was also not affected . With these studies, we demonstrated that the presence of an intact stn gene contributed significantly to the overall virulence of S . typhimurium in a murine model .

J Diarrhoeal Dis Res, 1998 Dec, 16(4), 248 - 51
Detection of Shigellae from stools of dysentery patients by culture and polymerase chain reaction techniques; Islam MS et al.; In Bangladesh, the isolation rates of Shigella spp . range from 11% to 12% by the conventional culture technique . Since the sensitivity of this technique is low, the polymerase chain reaction (PCR) technique was used for detecting small number of Shigellae from patients' stools . Sensitivity and specificity of the two techniques were also compared . Stool samples were collected from 41 patients with dysentery who attended the Clinical Research and Service Centre of the ICDDR,B: Centre for Health and Population Research . All stool specimens were directly plated onto MacConkey, Salmonella-Shigella, Xylose lysin deoxycholate and Hectoen enteric agar media, and Shigellae were detected following standard procedures . DNA was extracted from the stool samples, and the target sequence of invasive plasmid antigen (ipa)H locus was amplified by PCR with 130 ng each of two primers (primer H8 {5'-GTTCCTTGACCGCCTTTCCGATAC-3'} and primer H15 {5'-GCCGGTCAGCCACCCTA-3'}) following standard procedures . The amplified product was hybridized using an ipaH probe . The isolation rates of Shigella dysenteriae type 1, S . flexneri, S . sonnei, and S . boydii were, respectively, 17.1%, 19.5%, 4.9% and 2.4% by the conventional method . The results of the PCR technique showed that 700 bp fragment was generated in 18 of the 18 culture-positive and in 7 of the 23 culture-negative stools . One hundred twenty-three strains of Escherichia coli were also tested by PCR for identifying the enteroinvasive E . coli, but none of them yielded any positive result . This study showed that the sensitivity of the culture technique is 72% and specificity is 100%, when the PCR technique was considered as gold standard . Therefore, the PCR may be considered a more sensitive and specific technique than the conventional culture technique and has the potential to be employed in routine diagnosis of dysentery in clinical centres as well as in epidemiologic studies.

J Med Microbiol, 1999 Aug, 48(8), 771 - 80
The role of flagella, but not fimbriae, in the adherence of Salmonella enterica serotype Enteritidis to chick gut explant; Allen-Vercoe E et al.; To gain an understanding of the role of fimbriae and flagella in the adherence and colonisation of Salmonella enterica serotype Enteritidis in chickens, an in-vitro gut adherence assay was developed and used to assess the adherence of a wild-type Enteritidis strain and isogenic non-fimbriate and non-flagellate mutant strains . Enteritidis strain S1400/94, a clinical isolate virulent in chickens, was shown to possess genes which encoded type 1, SEF14, SEF17, plasmid-encoded and long polar fimbriae . Mutant strains unable to elaborate these fimbriae were created by allelic exchange . Each fimbrial operon was inactivated by the insertion of an antibiotic resistance gene cassette . In addition, fliC, motAB and cheA loci, which encode the major subunit of the flagellum, the energy-translation system for motility and one of the chemotaxis signalling proteins, respectively, were similarly inactivated . Non-flagellate mutant strains were significantly less adherent than the wild-type strain, whereas mutant strains defective for the elaboration of any of the types of fimbriae adhered as well as the wild-type strain . A flagellate but non-motile (paralysed) mutant strain and a smooth-swimming chemotaxis-deficient mutant strain were shown to be less adherent than the wild-type strain, but that observation depended on the assay conditions used.

Trans R Soc Trop Med Hyg, 1999 Mar-Apr, 93(2), 127 - 9
An update on concurrent malaria and typhoid fever in Cameroon; Ammah A et al.; Malaria and typhoid fever are endemic diseases in Cameroon, with overlapping signs and symptoms . While the high prevalence of malaria is an established fact, it is only within the past 5 years that an unusually high number of illnesses have been diagnosed as malaria co-existing with typhoid fever . The Widal test is widely used as the sole laboratory test for the diagnosis of typhoid fever . To investigate the extent of the malaria and typhoid fever association, we used blood and stool cultures as additional diagnostic tests for typhoid fever . We report that, of 200 patients presenting with fever, 17.0% had concurrent malaria and typhoid fever (Salmonella typhi) based on bacteriological proven diagnosis as compared with 47.9% based on the Widal test . A higher proportion of patients (32.5%) had malaria coexisting with S . typhimurium when compared to S . paratyphi (2%) and S . typhi (P < 0.05) . We conclude that the number of fever cases diagnosed as malaria co-existing with typhoid fever is overestimated.

Boll Chim Farm, 1999 May, 138(5), 207 - 10
Synthesis, characterization and antimicrobial studies of metal(II) bis-chelates and mixed-ligand complexes of alpha-(2-hydroxyphenyl)-N-(1-phenyl-2-nitroethyl)nitrone; Thirumalaikumar M et al.; This paper describes the synthesis of complexes of the type MB2 . 2H2O and CuBL.2H2O where BH = alpha-(2-hydroxyphenyl)-N-(1-phenyl-2-nitroethyl)-nitrone, M = copper(II)/cobalt(II)/nickel(II) and LH = salicylaldehyde/salicylaldoxime/8-hydroxyquinoline/2-hydroxypyridine . The magnetic moment, ligand field spectra, thermal and ESR studies reveals that these dihydrates possess octahedral geometry . The antimicrobial studies of these complexes against several microorganisms such as Staphylococcus aureus, Escherichia coli, Klebsiella aerogenes, Salmonella typhi and Pseudomonas sp . have been tested and reported in comparison with ceftazidime standard.

J Clin Microbiol, 1999 Sep, 37(9), 2882 - 6
Value of a single-tube widal test in diagnosis of typhoid fever in Vietnam; Parry CM et al.; The diagnostic value of an acute-phase single-tube Widal test for suspected typhoid fever was evaluated with 2,000 Vietnamese patients admitted to an infectious disease referral hospital between 1993 and 1998 . Test patients had suspected typhoid fever and a blood culture positive for Salmonella typhi (n= 1,400) or Salmonella paratyphi A (n = 45) . Control patients had a febrile illness for which another cause was confirmed (malaria {n = 103}, dengue {n = 76}, or bacteremia due to another microorganism {n = 156} or tetanus (n = 265) . An O-agglutinin titer of >/=100 was found in 18% of the febrile controls and 7% of the tetanus patients . Corresponding values for H agglutinins were 8 and 1%, respectively . The O-agglutinin titer was >/=100 in 83% of the blood culture-positive typhoid fever cases, and the H-agglutinin titer was >/=100 in 67% . The disease prevalence in investigated patients in this hospital was 30.8% (95% confidence interval, 26.8 to 35.1%); at this prevalence, an elevated level of H agglutinins gave better positive predictive values for typhoid fever than did O agglutinins . With a cutoff titer of >/=200 for O agglutinin or >/=100 for H agglutinin, the Widal test would diagnose correctly 74% of the blood culture-positive cases of typhoid fever . However, 14% of the positive results would be false-positive, and 10% of the negative results would be false-negative . The Widal test can be helpful in the laboratory diagnosis of typhoid fever in Vietnam if interpreted with care.

Microbiol Immunol, 1999, 43(5), 461 - 9
The role of intrahepatic gammadelta-T cells for liver injury induced by Salmonella infection in mouse; Ishigami M et al.; Liver injury was induced after infection with Salmonella choleraesuis 31N-1 . In T-cell receptor-delta knockout mice, serum alanine transferase level was significantly decreased in comparison with normal control mice after Salmonella infection . On the contrary, in vivo administration of anti-gammadelta T-cell receptor monoclonal antibody (UC7-13D5) to stimulate gammadelta-T cells in infected mice significantly increased serum alanine transferase level but decreased bacterial growth compared with infected mice given control antibody (UC8; hamster IgG) . These data suggest that gammadelta-T cells have effector activities not only for protection but also for liver injury during Salmonella infection.

Scand J Immunol, 1999 Aug, 50(2), 188 - 94
Influence of immunopotentiators on the antiporin immunoglobulin G subclass: distribution and protective immunity against murine salmonellosis; Nandakumar KS et al.; To improve the immune potential of porin (a pore-forming protein of Salmonella sp.), different immunopotentiators such as Freund's complete adjuvant (FCA), lipopolysaccharide (LPS) and polyoxydonium (PO) were evaluated by studying the nature of the protective immune response induced against murine Salmonellosis . The nontoxic, synthetic heteropolymer polyoxydonium was as good as LPS at inducing antiporin immunoglobulin G (IgG) antibodies and protective immunity . Analysis of the antiporin IgG subclass pattern revealed a preferential increase in a particular subclass based on the immunopotentiator used . Porin, alone or emulsified in FCA, elicited predominantly antiporin IgG1 antibodies, whereas LPS preferentially evoked antiporin IgG2a, IgG2b and IgG3 antibodies . Polyoxydonium induced a clear shift towards antiporin IgG2b antibodies . The significance of these antiporin IgG subclass antibodies in protection against murine Salmonellosis was studied by passive immunization and by analysing the infected mouse sera.

Mol Microbiol, 1999 Aug, 33(4), 791 - 805
Identification and molecular characterization of a novel Salmonella enteritidis pathogenicity islet encoding an ABC transporter; Pattery T et al.; Using a newly constructed minitransposon with a phoA reporter gene in a Salmonella enteritidis phoN mutant, we have identified an iron- and pH-inducible lipoprotein gene sfbA, which is a component of a novel ABC-type transporter system required for virulence . This gene is located on a 4 kb Salmonella-specific chromosomal segment, which constitutes a new pathogenicity islet . This islet encodes an outer membrane protein, OmpX, and contains the operon designated sfbABC (Salmonella ferric binding) encoding a putative periplasmic iron-binding lipoprotein SfbA, a nucleotide-binding ATPase SfbB and a cytoplasmic permease SfbC, as predicted by their characteristic signature sequences . Inactivation of the sfbA gene resulted in a mutant that is avirulent and induces protective immunity in BALB/c mice . The wild-type phenotype could be restored by in vivo complementation with the sfbABC operon . This novel transporter might be involved in iron uptake in Salmonella.

Shock, 1999 Aug, 12(2), 105 - 10
Protective effect of tyrphostin AG-556 on shock induced by endotoxin or gram positive bacteria; Ogura S et al.; The effects of tyrphostin AG-556 (TYR), a tyrosine kinase inhibitor, were evaluated on shock induced by lipopolysaccharide (LPS) or group B streptococcus (GBS) in rats . Mortality and mean survival time were monitored . Plasma 6-keto prostaglandin F1alpha (6-keto PGF1alpha) was also measured at four hours after LPS injection . The effects of TYR on the production of 6-keto PGF1alpha thromboxane B2(TXB2) and nitrite (NO) from LPS or GBS stimulated in vitro peritoneal rat macrophage were also examined . Salmonella enteritidis LPS (12 mg/kg, i.v . ) (n=6) produced severe shock (100% mortality) . Simultaneous treatment with TYR (n=6) significantly (p < 0.01) extended mean survival time and 33% of rats survived . Plasma 6-keto PGF1alpha concentrations were increased in LPS controls, whereas TYR (5 mg/kg) significantly (p < 0.05) decreased the production . Animals treated with GBS/D-galactosamine (n=9) also exhibited shock with 100% lethality and TYR again prolonged survival time (p < 0.05) with 55% of the animals surviving . To evaluate direct effects of TYR on mediator production induced by LPS or GBS, rat macrophages were stimulated with heat-killed GBS or LPS with or without TYR . Supernatants were collected at 24 h for determination of TXB2, 6-keto PGF1alpha and NO . All mediators measured were significantly increased (p < 0.05) with LPS or GBS . TYR inhibited (p < 0.05) the production of all mediators from macrophages induced by LPS or GBS . The decrease in eicosanoids was associated with a reduction of the content of cyclooxygenase-2 (COX-2) as determined by western blotting . Collectively, these results suggest that TYR ameliorates toxic shock induced by LPS or gram positive bacteria . This protection is associated with suppression of macrophage mediator production.

Am J Physiol, 1999 Aug, 277(2 Pt 1), L310 - 9
P-selectin and ICAM-1 mediate endotoxin-induced neutrophil recruitment and injury to the lung and liver; Kamochi M et al.; The role of leukocyte adhesion molecules in endotoxin-induced organ injury was evaluated by administering intraperitoneal Salmonella enteritidis lipopolysaccharide (LPS) to wild-type (WT) mice, P-selectin-deficient mice, intercellular adhesion molecule (ICAM)-1-deficient mice, and P-selectin-ICAM-1 double-mutant mice . In WT mice, there was a sevenfold increase in the number of neutrophils present in the pulmonary vascular lavage fluid, and there were sevenfold more intracapillary neutrophils by electron-microscopic (EM) morphometry at 4 h after intraperitoneal LPS compared with that in control mice . Extravascular albumin accumulation increased approximately twofold in the lungs and liver of WT mice treated with LPS . In the double-mutant mice, although overall mortality after intraperitoneal LPS was not attenuated, there was a significant delay in mortality in the P-selectin-ICAM-1-deficient mutants compared with that in WT mice after intraperitoneal LPS (P < 0.01) . Moreover, compared with LPS-treated WT mice, lung and liver extravascular albumin accumulation was significantly lower in LPS-treated P-selectin-ICAM-1 double-mutant mice . Lung myeloperoxidase activity, normalized per 1,000 circulating neutrophils, increased after endotoxin in WT and P-selectin-deficient mice but not in P-selectin-ICAM-1 double-mutant mice . In addition, lung and liver myeloperoxidase activity per 1,000 circulating neutrophils in endotoxin-treated ICAM-1-deficient mice and P-selectin-ICAM-1 double mutants was significantly lower compared with that in endotoxin-treated WT mice . These data suggest that P-selectin and ICAM-1 significantly contribute to lung and liver injury after systemic endotoxemia.

J AOAC Int, 1999 Jul-Aug, 82(4), 871 - 6
Routine detection of Salmonella species in water: comparative evaluation of the ISO and PROBELIA polymerase chain reaction methods; Coquard D et al.; Water is one of the main transmission routes for Salmonella spp., the causative agents of salmonellosis in humans and animals . This worldwide sanitary problem requires rapid and accurate analyses to be realized so that advisories for exposed people are timely and reliable . Because the traditional method, the ISO 6340 method, does not meet the criterion of rapidity, there was a need for a quicker method . To fulfill this need, a comparative evaluation between the ISO method and one based on polymerase chain reaction (PCR), the PROBELIA, was performed . Waters from different origins were tested either directly or after artificial contamination with selected Salmonella strains isolated from the environment . The results clearly demonstrate that the PCR-based method can advantageously replace the ISO 6340 method . It is quicker, less labor intensive, reproducible, and provides results that match perfectly to those obtained by the ISO method . Furthermore, the PROBELIA method meets the requirements for an efficient sanitary survey: high numbers of samples processed at the same time, reduced cost, and results within 2 days.

Int J Food Microbiol, 1999 Jun 1, 48(3), 221 - 4
An immunoconcentration-PCR assay to detect Salmonella in the environment of poultry houses; Soumet C et al.; An immunoconcentration-PCR assay was developed for the rapid and specific detection of Salmonella . This assay was evaluated against a conventional bacteriological method for the detection of Salmonella from environmental swabs of poultry houses . The 120 samples investigated were pre-enriched in phosphate buffered peptone water and Salmonella was separated by an immunoconcentration process using an automated system (VIDAS bioMerieux, Marcy l'Etoile, France) prior to PCR . The specificity of the assay was high as no false-positives were found . The sensitivity of the assay was 70% . The correlation between the ICS-PCR assay and the bacteriological method was 84%.

Phytother Res, 1999 Aug, 13(5), 397 - 400
Mutagenicity of medicinal plant extracts in Salmonella/microsome assay; de Sa Ferreira IC et al.; Aqueous extracts of medicinal plants used in south Brazilian folk medicine (Myrciaria tenella, Smilax campestris, Tripodanthus acutifolius and Cassia corymbosa) were screened for the presence of mutagenic activity in the Salmonella/microsome assay . Signs of an increased mutagenic induction below revertant rates, which is two times the spontaneous yields, were detected for all extracts . The extracts of C . corymbosa showed signs of mutagenic activity in the following strains: TA100 with and without metabolization and TA98 after metabolization . These mutagenic signs were observed in the M . tenella extracts without metabolization . S . campestris and T . acutifolius infusions also showed signs indicative of direct mutagenic activity in the TA98 strain . The positive results may be related to the presence of flavonoids, tannins and anthraquinones in the extracts .

Biochem Biophys Res Commun, 1999 Aug 11, 261(3), 844 - 7
Mutagenic activity and DNA adduct formation by 1, 2-epoxy-3-(p-nitrophenoxy)propane, an HIV-1 protease inhibitor and GST substrate; Said B et al.; Acid protease inhibitor 1,2-epoxy-3-(p-nitrophenoxy)propane (ENPP) is commonly used in research as a substrate for glutathione-S-transferase activity (GST) and recently was found to inhibit human immunodeficiency virus 1 (HIV-1) protease . The question of DNA-adduct formation and mutagenicity was investigated and found that ENPP causes DNA damage and acts directly to induce mutagenicity in Salmonella . Using HPLC analysis, ENPP was shown to bind covalently to guanine residues . The Salmonella mutagenicity assay indicated that ENPP enhanced the mutation frequencies in the base-substitution strain TA00 by more than 20 times above the background . Its mutagenic potency was comparable to that of well-known carcinogens, N-methyl-N-nitrosourea (MNU) and aflatoxin B(1)-8,9-epoxide (AFB(1)-8,9-epoxide) . The results suggest that ENPP should be classified as a mutagenic compound and a potential carcinogen .

Drugs, 1999 Jul, 58(1), 91 - 6; discussion 97-8
Bivalent cholera and typhoid vaccine; Foster RH et al.; The live attenuated vaccine strains Vibrio cholerae CVD 103-HgR and Salmonella typhi Ty21a can be combined into an oral bivalent vaccine without compromising the immunogenicity of the individual vaccine strains . Seroconversion rates of 87 to 94% for Inaba vibriocidal antibodies and 72 to 91% for anti-S . typhi lipopolysaccharide antibodies (IgG or IgA) were reported in healthy European volunteers receiving a bivalent CVD 103-HgR/Ty21a vaccine-based schedule (bivalent vaccine on day 1 and monovalent Ty21a vaccine on days 3 and 5) . The immunogenicity of bivalent CVD 103-HgR/Ty21a vaccine is not adversely affected by concomitant administration of mefloquine, yellow fever vaccine or oral polio vaccine . Chloroquine may reduce the immunogenicity of the CVD 103-HgR component and proguanil may reduce the immunogenicity of the Ty21a component . Bivalent CVD 103-HgR/Ty21a vaccine does not adversely affect the immunogenicity of the yellow fever YF 17D vaccine . The type, incidence and severity of adverse events seen in individuals receiving bivalent CVD 103-HgR/Ty21a vaccine-based schedules are similar to those that occur with the monovalent vaccines.

Microbiology, 1999 Jul, 145 ( Pt 7), 1769 - 75
FliL is a membrane-associated component of the flagellar basal body of Salmonella; Schoenhals GJ et al.; FliL is one of the least understood proteins in the flagellar systems of Salmonella and Escherichia coli . There is no apparent mutant phenotype associated with it, even when virtually the entire coding sequence has been eliminated . In this study it has been shown that FliL is a cytoplasmic membrane protein associated with the basal body . Although it has a sequence that conforms to the consensus cleavage site for lipoproteins, FliL does not undergo cleavage or modification under physiological conditions.

J Immunol, 1999 Aug 15, 163(4), 2057 - 63
Regulatory role of peritoneal NK1.1+ alpha beta T cells in IL-12 production during Salmonella infection; Naiki Y et al.; NK1.1+ alpha beta T cells emerge in the peritoneal cavity after an i.p . infection with Salmonella choleraesuis in mice . To elucidate the role of the NK1.1+ alpha beta T cells during murine salmonellosis, mice lacking NK1.1+ alpha beta T cells by disruption of TCR beta (TCR beta-/-), beta 2m (beta 2m-/-), or J alpha 281 (J alpha 281-/-) gene were i.p . inoculated with S . choleraesuis . The peritoneal exudate T cells in wild type (wt) mice on day 3 after infection produced IL-4 upon TCR alpha beta stimulation, whereas those in TCR beta-/-, beta 2m-/-, or J alpha 281-/- mice showed no IL-4 production upon the stimulation, indicating that NK1.1+ alpha beta T cells are the main source of IL-4 production at the early phase of Salmonella infection . Neutralization of endogenous IL-4 by administration of anti-IL-4 mAb to wt mice reduced the number of Salmonella accompanied by increased IL-12 production by macrophages after Salmonella infection . The IL-12 production by the peritoneal macrophages was significantly augmented in mice lacking NK1.1+ alpha beta T cells after Salmonella infection accompanied by increased serum IFN-gamma level . The aberrantly increased IL-12 production in infected TCR beta-/- or J alpha 281-/- mice was suppressed by adoptive transfer of T cells containing NK1.1+ alpha beta T cells but not by the transfer of T cells depleted of NK1.1+ alpha beta T cells or T cells from J alpha 281-/- mice . Taken together, it is suggested that NK1 . 1+ alpha beta T cells eliciting IL-4 have a regulatory function in the IL-12 production by macrophages at the early phase of Salmonella infection.

Blood, 1999 Aug 15, 94(4), 1330 - 6
Increased clearance explains lower plasma levels of tissue-type plasminogen activator by estradiol: evidence for potently enhanced mannose receptor expression in mice; Lansink M et al.; Several clinical studies have demonstrated an inverse relationship between circulating levels of estrogen and tissue-type plasminogen activator (t-PA) . The present study was designed to test the hypothesis that estrogens lower plasma levels of t-PA by increasing its clearance from the bloodstream . 17alpha-Ethinyl estradiol (EE) treatment resulted in a significant increase in the clearance rate of recombinant human t-PA in mice (0.46 mL/min in treated mice v 0 . 32 mL/min in controls; P <.01) . The clearance of endogenous, bradykinin-released t-PA in rats was also significantly increased after EE treatment (area under the curve {AUC}, 24.9 ng/mL . min in treated animals v 31.9 ng/mL . min in controls; P <.05) . Two distinct t-PA clearance systems exist in vivo: the low-density lipoprotein receptor-related protein (LRP) on liver parenchymal cells and the mannose receptor on mainly liver endothelial cells . Inhibition of LRP by intravenous injection of receptor-associated protein (RAP) as a recombinant fusion protein with Salmonella japonicum glutathione S-transferase (GST) significantly retarded t-PA clearance in control mice (from 0.41 to 0.25 mL/min; n = 5, P <.001) and EE-treated mice (from 0.66 to 0.35 mL/min; n = 5, P <.005), but did not eliminate the difference in clearance capacity between the 2 experimental groups . Similar results were obtained in mice in which LRP was inhibited via overexpression of the RAP gene in liver by adenoviral gene transduction . In contrast, administration of mannan, a mannose receptor antagonist, resulted in identical clearances (0.22 mL/min in controls and 0.24 mL/min in EE-treated mice) . Northern blot analysis showed a 6-fold increase in mannose receptor mRNA expression in the nonparenchymal liver cells of EE-treated mice, whereas the parenchymal LRP mRNA levels remained unchanged . These findings were confirmed at the protein level by ligand blotting and Western blotting analysis . Our results demonstrate that EE treatment results in increased plasma clearance rate of t-PA via induction of the mannose receptor and could explain for the inverse relationship between estrogen status and plasma t-PA concentrations as observed in humans.

J Ethnopharmacol, 1999 Jul, 66(1), 79 - 82
Antimicrobial activity of Byrsonima crassifolia (L.) H.B.K; Martinez-Vazquez M et al.; From Byrsonima crassifolia (L.) H.B.K . a tropical tree widely distributed in Mexico, Central and South America, which has been used medicinally since prehispanic times, we report here the antibacterial activities of organic extracts of roots and stems . The ethyl acetate of roots was the most active against Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, Shigella flexneri, Staphylococcus aureus, Staphylococcus epididermis, Streptococcus pneumoniae and Micrococcus luteus.

Am J Trop Med Hyg, 1999 Jul, 61(1), 163 - 70
Considerations regarding mass vaccination against typhoid fever as an adjunct to sanitation and public health measures: potential use in an epidemic in Tajikistan; Tarr PE et al.; We report on the ongoing epidemic of typhoid fever in Tajikistan that started in 1996 . It has involved more than 24,000 cases to date, and is characterized by multiple point sources, overflow of sewage, contaminated municipal water, and person-to-person spread . Of the Salmonella typhi isolates available for testing in western laboratories, more than 90% are multidrug-resistant (MDR) . Most recently, 28 (82%) of 34 isolates are resistant to ciprofloxacin, representing the first reported epidemic of quinolone-resistant typhoid fever . In the past, mass immunization during typhoid fever epidemics has been discouraged . A review of this policy is recommended in light of the alarming emergence of quinolone-resistant strains of S . typhi, the availability of improved vaccines, and the ongoing epidemic in Tajikistan . Mass immunization may be a useful measure for the control of prolonged MDR typhoid fever epidemics, as an adjunct to correction of municipal infrastructure and public health intervention.

MMWR Morb Mortal Wkly Rep, 1999 Jul 16, 48(27), 582 - 5
Outbreak of Salmonella serotype Muenchen infections associated with unpasteurized orange juice--United States and Canada, June 1999; Binding of extracellular matrix laminin to Escherichia coli expressing the Salmonella outer membrane proteins Rck and PagC; Department of Pathology, University of Cambridge, UKSalmonella Rck and PagC are closely related virulence-associated proteins . When expressed in non-adherent, non-invasive laboratory Escherichia coli, both proteins localised to the outer membrane . Only Rck conferred adhesion to culture cells, but both proteins induced bacterial binding to the cell monolayer background, to extracellular matrix (ECM) preparations, and to the ECM component laminin . Laminin binding was saturable and competitive, and was reduced by removal of carbohydrate side chains . Pre-incubation with laminin targeted recombinant Rck and PagC bacteria directly to the eukaryotic cell surface, and eliminated background binding.

Appl Environ Microbiol, 1999 Aug, 65(8), 3582 - 7
Use of single-strand conformation polymorphism analysis to examine the variability of the rpoS sequence in environmental isolates of Salmonellae; Jordan SJ et al.; The natural environment places its resident microflora under stress, which may often result in adaptation by the microflora in order to increase the probability of survival . One such mechanism that has been postulated involves rpoS, which encodes a sigma factor that is known to enhance survival upon exposure to stress . The present work aimed to examine the genetic variability of rpoS in a selection of Salmonella enterica subspecies environmental isolates with an automated single-strand conformation polymorphism analysis technique . The results indicated that sequence variation does occur and that these changes are mainly located in two areas: at the center and near the end of the coding region . The variability was generally at the single-base level, although one strain (S . arizonae) did demonstrate significant differences in nucleotide sequence.

Nat Struct Biol, 1999 Aug, 6(8), 755 - 9
The tetramerization domain of the Mnt repressor consists of two right-handed coiled coils; Nooren IM et al.; The tetrameric Mnt repressor is involved in the genetic switch between the lysogenic and lytic growth of Salmonella bacteriophage P22 . The solution structure of its C-terminal tetramerization domain, which holds together the two dimeric DNA-binding domains, has been determined by NMR spectroscopy . This structure reveals an assembly of four alpha-helical subunits, consisting of a dimer of two antiparallel coiled coils with a unique right-handed twist . The superhelical winding is considerably stronger and the interhelical separation closer than those found in the well-known left-handed coiled coils in fibrous proteins and leucine zippers . An unusual asymmetry arises between the two monomers that comprise one right-handed coiled coil . A difference in the packing to the adjacent monomer of the other coiled coil occurs with an offset of two helical turns . The two asymmetric monomers within each coiled coil interconvert on a time scale of seconds . Both with respect to symmetry and handedness of helical packing, the C2 symmetric four-helix bundle of Mnt differs from other oligomerization domains that assemble DNA-binding modules, such as that in the tumor suppressor p53 and the E . coli lac repressor.

Int J Food Microbiol, 1999 May 1, 48(2), 139 - 48
Efficacy of Salmonella enteritidis-immune lymphokines on horizontal transmission of S . arizonae in turkeys and S . gallinarum in chickens; Lowry VK et al.; Salmonella arizonae (SA) and S . gallinarum (SG) are of economic importance to international poultry production because of their pathogenesis in young poultry during the first week after hatching . Previous studies from our laboratory have shown immune lymphokines (ILK) produced by S . enteritidis (SE)-immunized chickens provide protection against SE organ invasion in day-old chickens and turkey poults . Previous studies have also demonstrated that SG organ invasion was significantly decreased by administration of ILK to broiler chicks . The objective of the present study was to determine the effect of ILK on the incidence of horizontal transmission of SA in turkey poults and of SG in broiler chicks . The effect of ILK administration on horizontal transmission of SA in poults and SG in chicks was assessed in a seeder/contact model . Seeders were challenged with the appropriate bacterium (SA turkeys, SG chicks), contacts were either untreated or administered ILK . Seeders and contacts cohabited within an experimental group throughout the experiment . Mortality and organ invasion as a result of horizontal transmission were determined . There were no significant differences in mortality between non-treated and ILK-treated contact poults . In contrast, SG was extremely pathogenic to young broiler chicks . Non-treated contact chicks had a mortality rate of approximately 68% whereas significant (P < 0.05) reduction in mortality was demonstrated in the contact chicks treated with ILK (15%) . Horizontal transmission, as determined by organ invasion, of SA to contact turkey poults and SG to contact broiler chicks was also significantly (P <0.05) decreased by immunoprophylactic administration of ILK . Bacterial recovery of SA from the liver/spleen and the cecal tonsil in contact poults and SG from contact chicks treated with ILK was dramatically reduced when compared to non-treated contact poults and chicks . Our results strongly suggest the immunoprophylactic administration of SE-immune lymphokines to young turkey poults and broiler chicks significantly reduces the horizontal transmission of Salmonella in poultry . These results suggest the possibilities of using a non-vaccine immunologically-based preventative strategy against Salmonella in poultry.

Res Vet Sci, 1999 Aug, 67(1), 99 - 101
Enterotoxigenicity of Salmonellae isolated from dogs in Nigeria; Chah KF et al.; Salmonella dublin, S agama and S typhimurium isolated from local dogs were tested for enterotoxigenic activity using Guinea-Pig Ligated Ileal Loop Technique . One millilitre each of whole-cell culture (WCC) and cell-free filtrate (CFF) of each isolate was injected into replicates of ligated loops . Enterotoxigenic activity, measured as mean dilatation index (DI) was determined for WCC and CFF of each isolate . Both WCC and unheated CFF of all the serotypes induced considerable fluid accumulation in the loops . The mean DI produced by WCC and unheated CFF varied significantly among the three serotypes . This variation seems to support the concept of multiple mechanisms for salmonella-induced diarrhoea .

Prev Vet Med, 1999 Jun 11, 40(3-4), 277 - 92
Salmonella level of Danish swine herds based on serological examination of meat-juice samples and Salmonella occurrence measured by bacteriological follow-up; Christensen J et al.; Analyses of data collected in the Danish Salmonella Control Program in swine herds were conducted to assess the association between bacteriological and serological findings (including the degree to which changing serological status over time modulated the relationship) and to assess the degree to which type of swine operation and age group affected the relationship between bacteriological and serological findings . Although serological status was significantly associated with bacteriological prevalence of salmonella enterica in swine herds, the association was clarified by adding information on the change in serological status over time and the age group being tested . Salmonella infection assessed by serological tests at a single time-point and data on age group tested would allow better targeting and managing control programs.

New Microbiol, 1999 Jul, 22(3), 195 - 202
Detection of Salmonella spp . in food by a rapid PCR-hybridization procedure; Nastasi A et al.; A rapid and sensitive PCR-hybridization procedure for detection of Salmonella serovars in food samples was developed . This method is based on three subsequent steps: (1) extraction of nucleic acids from a 2 ml aliquot of the pre-enrichment medium used for the conventional culture method after 6 h of incubation at 37 degrees C; (2) amplification with primers selected from the sequences of invE and invA genes; (3) Southern blot and hybridization with a biotin labeled oligonucleotide probe . The entire procedure requires 30 h . The PCR-hybridization assay was able to detect as little as 50 fg of purified chromosomal DNA of S . typhimurium and 0.2 cfu g-1 of an artificially contaminated food sample . Of 245 food samples analyzed by culture and PCR-hybridization, 20 were positive by both methods and 16 were positive by PCR-hybridization only . None of the 209 PCR-negative samples tested positive by culture . The sensitivity, specificity, alpha and beta error values of the results of the PCR-hybridization procedure, compared with those of culture, were 100, 92.9, 0 and 7.1%, respectively . These results indicate that a short pre-enrichment and PCR-hybridization could be used as a screening test for the detection of Salmonella in food samples.

J Food Prot, 1999 Jul, 62(7), 778 - 85
Use of hazard analysis critical control point and alternative treatments in the production of apple cider; Senkel IA Jr et al.; The purpose of this study was to evaluate the practices of Maryland cider producers and determine whether implementing hazard analysis critical control point (HACCP) would reduce the microbial contamination of cider . Cider producers (n = 11) were surveyed to determine existing manufacturing practices and sanitation . A training program was then conducted to inform operators of safety issues, including contamination with Escherichia coli O157:H7, and teach HACCP concepts and principles, sanitation procedures, and good manufacturing practice (GMP) . Although all operators used a control strategy from one of the model HACCP plans provided, only one developed a written HACCP plan . None developed specific GMP, sanitation standard operating procedures, or sanitation monitoring records . Six operators changed or added production controls, including the exclusion of windfall apples, sanitizing apples chemically and by hot dip, and cider treatment with UV light or pasteurization . Facility inspections indicated improved sanitation and hazard control but identified ongoing problems . Microbiological evaluation of bottled cider before and after training, in-line apples, pomace, cider, and inoculated apples was conducted . E . coli O157:H7, Salmonella, or Staphylococcus aureus were not found in samples of in-line apple, pomace, and cider, or bottled cider . Generic E . coli was not isolated on in-coming apples but was found in 4 of 32 (13%) in-line samples and 3 of 17 (18%) bottled fresh cider samples, suggesting that E . coli was introduced during in-plant processing . To produce pathogen-free cider, operators must strictly conform to GMP and sanitation procedures in addition to HACCP controls . Controls aimed at preventing or eliminating pathogens on source apples are critical but alone may not be sufficient for product safety.

J Food Prot, 1999 Jul, 62(7), 805 - 7
Fate of Escherichia coli O157:H7 and Salmonella Enteritidis on currency; Jiang X et al.; The fate of foodborne pathogens Escherichia coli O157:H7 and Salmonella Enteritidis on coin surfaces was determined at room temperature (25 degrees C) . A five-strain mixture of E . coli O157:H7 or Salmonella Enteritidis of approximately 5 x 10(4) CFU was applied to the surfaces of sterile U.S . coins (pennies, nickels, dimes, and quarters) and to the surfaces of two control substrata (Teflon and glass coverslips) . During storage at room temperature, E . coli O157:H7 survived for 7, 9, and 11 days on the surfaces of pennies, nickels, and dimes and quarters, respectively . However, the pathogen died off within 4 to 7 days on both the Teflon and glass surfaces . Salmonella Enteritidis survived for 1, 2, 4, and 9 days on the surfaces of pennies, nickels, quarters, and dimes, respectively . Unlike E . coli O157:H7, survival of Salmonella Enteritidis was greatest on both Teflon and glass coverslips, with more than 100 cells per substratum detected at the 17th day of storage . Results indicate that coins could serve as potential vehicles for transmitting both E . coli O157:H7 and Salmonella Enteritidis.

J Food Prot, 1999 Jul, 62(7), 751 - 5
Antagonistic effect of Enterococcus faecium J96 against human and poultry pathogenic Salmonella spp; Audisio MC et al.; Production of antagonistic compounds was studied in a strain of Enterococcus faecium isolated from the intestinal tract of a free-ranging chicken . Production of lactic acid and a bacteriocin was observed in cultures of this bacterium, alone and in mixed culture fermentations with pathogenic Salmonella serotypes (i.e., Gallinarum, Pullorum, Enteritidis, and Typhimurium) . Growth inhibition of these avian and human pathogens was observed after 4 h of incubation at 37 degrees C in CAm broth, a medium developed according to the nutrients present in chicken food . The antibacterial action was due to the combined effect of lactic acid and bacteriocin . Accumulation of these metabolites caused both a bacteriostatic and a bactericidal action against the gram-negative bacteria assayed.

J Food Prot, 1999 Jul, 62(7), 724 - 30
Use of selective media to recover Salmonella and Vibrio cholerae after growth in reconditioned pork-processing wastewater; Rajkowski KT et al.; Selective plating media are used for the enumeration and isolation of bacterial pathogens from food and water samples . This study compared the quantitative recovery of Salmonella spp . and Vibrio cholerae grown in nutrient-limited, filter-sterilized, reconditioned wastewater over the temperature range of 4 to 45 degrees C using nonselective and pathogen-specific selective media . Viable Salmonella were enumerated on tryptic soy agar (TSA) and XLT-4, and viable V . cholerae were enumerated on TSA and thiosulfate-citrate-bile-sucrose agar . There was a statistically significant (P < 0.05) higher recovery of both pathogens over the growth temperature range on TSA compared to the selective media . Trehalose, a stress-induced metabolite of Salmonella, was isolated from the cells grown in the reconditioned wastewater, whereas, the V . cholerae exhibited a change in cellular morphology from rod to coccoid shape . These results suggest that growth in nutrient-limited water injured or stressed the individual pathogens . Care should be used in choosing the procedure and plating medium for quantitative recovery of pathogens from such a nutrient-limiting environment.

Vaccine, 1999 Jun 4, 17(20-21), 2636 - 45
Bacterial expression of the major antigenic regions of porcine rotavirus VP7 induces a neutralizing immune response in mice; Wang L et al.; The outer capsid protein of rotavirus, VP7, is a major neutralization antigen . A chimeric protein comprising Escherichia coli (E . coli) outer membrane protein A (OmpA) and part of porcine rotavirus VP7 containing all three antigenic regions (217 amino acids) was expressed in Salmonella and E . coli as an outer-membrane associated protein . Mice immunized intraperitoneally or orally, respectively, with live E . coli or Salmonella cells expressing this chimeric protein produced antibodies against native VP7 as determined by enzyme-linked immunosorbent assays and neutralization tests . This indicates that the VP7 fragment from a porcine rotavirus which is antigenically similar to human rotavirus serotype 3, when expressed in bacteria as a chimeric protein, can form a structure resembling its native form at least in some of the major neutralization domains . These results indicate that the use of a live bacterial vector expressing rotavirus VP7 may represent a strategy for the development of vaccines against rotavirus-induced diarrhoea in infants.

Vaccine, 1999 Jun 4, 17(20-21), 2538 - 45
Vaccination for control of Salmonella in poultry; Zhang-Barber L et al.; Salmonella spp . are facultative intracellular pathogens causing localised or systemic infections, in addition to a chronic asymptomatic carrier state . They are of worldwide economic and public health significance . In poultry, which represent important sources of cheap protein throughout the world, fowl typhoid and pullorum disease continue to cause economic losses in those parts of the world where the poultry industries are continuing to intensify and where open sided housing is common . A number of serotypes that cause human gastro-enteritis are also increasing . The costs or impracticality of improvements in hygiene and management together with the increasing problems of antibiotic resistance suggest that vaccination in poultry will become more attractive as an adjunct to existing control measures . However, our understandings of the immunology of Salmonella infections in poultry is rudimentary and much poorer than that of equivalent infections in mice and live vaccine development for poultry has therefore been largely empirical . In addition to the killed Salmonella vaccines which have been used over the past few years with variable efficacy, a number of live vaccines have become available and some new vaccines will appear on the market over the next few years . These new vaccines should fulfil the criteria of efficacy, safety and compatibility with existing systems for monitoring infection before they are released on to a mass market . In this review we attempt to summarise the current understanding of Salmonella immunology in poultry together with the progress that has been made in poultry vaccine development.

Zhonghua Yi Xue Za Zhi (Taipei), 1999 Jul, 62(7), 472 - 6
Salmonella infection in total hip replacement--report of successful reimplantation and review of the literature; Chen CM et al.; A case of Salmonella enteritidis group C infection following total hip replacement was treated by resectional arthroplasty and appropriate antibiotics . Total hip replacement with reimplantation of an antibiotic-impregnated cemented hip prosthesis was performed five months later . The postoperative course was smooth and hip function was good, without any sign of infection recurrence throughout 10 years of follow-up . The treatment protocol and clinical results are discussed along with a review of the literature.

FEMS Microbiol Lett, 1999 Jul 1, 176(1), 229 - 33
Characterization of IS1541-like elements in Yersinia enterocolitica and Yersinia pseudotuberculosis; Devalckenaere A et al.; We characterized Yersinia enterocolitica and Yersinia pseudotuberculosis insertion sequences related to insertion sequence 1541, recently identified in Yersinia pestis . For each of the two species, two insertion sequence copies were cloned and sequenced . Genetic elements from Y . pseudotuberculosis were almost identical to insertion sequence 1541, whereas these from Y . enterocolitica were less related . Phylogenetic analysis of the putative transposases encoded by insertion sequences from the three pathogenic members of the genus Yersinia showed that they clustered with those encoded by Escherichia coli and Salmonella enterica elements belonging to the insertion sequence 200/insertion sequence 605 group . Insertion sequences originating from Y . pestis and Y . pseudotuberculosis constitute a monophyletic lineage distinct from that of Y . enterocolitica.

Proc Assoc Am Physicians, 1999 Jul-Aug, 111(4), 283 - 9
The Nramp1 protein and its role in resistance to infection and macrophage function; Canonne-Hergaux F et al.; Susceptibility to infectious diseases is under genetic control in humans . Animal models provide an ideal tool to study the genetic component of susceptibility and to identify candidate genes that can then be tested for association or linkage studies in human populations from endemic areas of disease . The Nramp1 gene was isolated by positional cloning the host resistance locus Bcg/Ity/Lsh, and mutations at this locus impair the resistance of mice to infections with intracellular parasites, such as Salmonella, Leishmania, and Mycobacterium . Allelic variants at the human Nramp1 homologue have recently been found to be associated with susceptibility to tuberculosis and leprosy in humans . The Nramp1 protein is an integral membrane protein expressed exclusively in the lysosomal compartment of monocytes and macrophages . After phagocytosis, Nramp1 is targeted to the membrane of the microbe-containing phagosome, where it may modify the intraphagosomal milieu to affect microbial replication . Although the biochemical mechanism of action of Nramp1 at that site remains unknown, Nramp homologues have been identified in many other animal species and actually define a protein family conserved from bacteria to humans . Some of these homologues have been shown to be divalent cation transporters . Recently, a second member of the mammalian Nramp family, Nramp2, was discovered and shown to be mutated in animal models of iron deficiency . The Nramp2 protein was subsequently shown to be the major transferrin-independent iron uptake system of the intestine . Together, these results suggest that Nramp1 may control intracellular microbial replication by actively removing iron or other divalent cations from the phagosomal space.

Mol Microbiol, 1999 Aug, 33(3), 612 - 22
Multiple insertions of fimbrial operons correlate with the evolution of Salmonella serovars responsible for human disease; Folkesson A et al.; On centisome 7, Salmonella spp . contain a large region not present in the corresponding region of Escherichia coli . This region is flanked by sequences with significant homology to the E . coli tRNA gene aspV and the hypothetical E . coli open reading frame yafV . The locus consists of a mosaic of differentially acquired inserts forming a dynamic cs7 region of horizontally transferred inserts . Salmonella enterica subspecies I, responsible for most Salmonella infections in warm-blooded animals, carries a fimbrial gene cluster (saf) in this region as well as a regulatory gene (sinR) . These genes are flanked by inverted repeats and are inserted in another laterally transferred region present in most members of Salmonella spp . encoding a putative invasin (pagN ) . S . enterica subspecies I serovar Typhi, the Salmonella serovar that causes the most severe form of human salmonellosis, contains an additional insert of at least 8 kb in the sinR-pagN intergenic region harbouring a novel fimbrial operon (tcf ) similar to the coo operon encoding the CS1 fimbrial adhesin expressed by human-specific enterotoxigenic E . coli . It is suggested that the multiple insertions of fimbrial genes that have occurred in the cs7 region have contributed to phylogenetic diversity and host adaptation of Salmonella spp.

Infect Immun, 1999 Aug, 67(8), 4290 - 4
Expression and immunogenicity of a mutant diphtheria toxin molecule, CRM(197), and its fragments in Salmonella typhi vaccine strain CVD 908-htrA; Orr N et al.; Mutant diphtheria toxin molecule CRM(197) and fragments thereof were expressed in attenuated Salmonella typhi CVD 908-htrA, and the constructs were tested for their ability to induce serum antitoxin . Initially, expressed proteins were insoluble, and the constructs failed to induce neutralizing antitoxin . Soluble CRM(197) was expressed at low levels by utilizing the hemolysin A secretion system from Escherichia coli.

Arch Microbiol, 1999 Aug, 172(2), 102 - 8
Antibody responses against flagellin in mice orally immunized with attenuated Salmonella vaccine strains; De Almeida ME et al.; Salmonella fIagellin has been repeatedly used as a carrier for heterologous peptide epitopes either as a parenterally delivered purified antigen or as a parenterally/orally-administered, flagellated, live, attenuated vaccine . Nonetheless, the ability to induce specific antibody responses against the flagellin moiety, fused or not with heterologous peptide, has not usually been reported in mice orally inoculated with a live, attenuated, flagellated Salmonella strain . In this work we evaluated the immunogenicity of flagellin in mice following oral inoculation with an aroA Salmonella enterica serovar Dublin SL5929 strain, which expressed plasmid-encoded recombinant hybrid flagellin fused to the CTP3 epitope (amino acids 50-64) of cholera toxin B-subunit . In contrast to parenterally immunized mice, no significant CTP3- or flagellin-specific antibody responses either in sera (IgG) or feces (IgA) were detected following repeated oral delivery of the recombinant Salmonella strain to C57BL/6 mice . Similarly, flagellin-specific antibody responses were also not detected in mice immunized with strain SL5930, which expressed a nonhybrid flagellin . The lack of flagellin-specific antibody responses was not associated with deficient Peyer patch colonization or spleen invasion . Moreover, stabilization of the flagellin-coding gene by integration into the host chromosome did not significantly improve flagellin-specific antibody responses following administration by the oral route . Taken together, these results suggest that flagellin does not represent an efficient peptide carrier for activation of antibody responses in mice orally immunized with live, attenuated Salmonella strains.

J Immunol, 1999 Aug 1, 163(3), 1457 - 66
NF-kappa B is a central regulator of the intestinal epithelial cell innate immune response induced by infection with enteroinvasive bacteria; Elewaut D et al.; Human intestinal epithelial cells up-regulate the expression of an inflammatory gene program in response to infection with a spectrum of different strains of enteroinvasive bacteria . The conserved nature of this program suggested that diverse signals, which are activated by enteroinvasive bacteria, can be integrated into a common signaling pathway that activates a set of proinflammatory genes in infected host cells . Human intestinal epithelial cell lines, HT-29, Caco-2, and T84, were infected with invasive bacteria that use different strategies to induce their uptake and have different intracellular localizations (i.e., Salmonella dublin, enteroinvasive Escherichia coli, or Yersinia enterocolitica) . Infection with each of these bacteria resulted in the activation of TNF receptor associated factors, two recently described serine kinases, I kappa B kinase (IKK) alpha and IKK beta, and increased NF-kappa B DNA binding activity . This was paralleled by partial degradation of I kappa B alpha and I kappa B epsilon in bacteria-infected Caco-2 cells . Mutant proteins that act as superrepressors of IKK beta and I kappa B alpha inhibited the up-regulated transcription and expression of downstream targets genes of NF-kappa B that are key components of the epithelial inflammatory gene program (i.e., IL-8, growth-related oncogene-alpha, monocyte chemoattractant protein-1, TNF-alpha, cyclooxygenase-2, nitric oxide synthase-2, ICAM-1) activated by those enteroinvasive bacteria . These studies position NF-kappa B as a central regulator of the epithelial cell innate immune response to infection with enteroinvasive bacteria.

Eur J Epidemiol, 1999 Apr, 15(4), 395 - 401
Comparison of two Salmonella enteritidis phage typing schemes; Glosnicka R et al.; The comparison of two phage typing schemes for Salmonella enteritidis was performed . A total of 517 strains were phage-typed according to the schemes of Lalko {27} and Ward et al . {21} . Strains were isolated from food-poisoning outbreaks and other common sources in Poland, between 1986-1995 . Above 99% of all strains tested were differentiated to the definitive phage type using the Lalko collection of typing phages . Phage types 1 and 7 (PTs 1, 7) were the most isolated . The typing phages of Ward enabled to assign 56.5% of all strains (a total of 14 phage types were presented), 37.1% - reacted with phages without showing any of the designated phage types and 6.4% were untypable . Phage type 8 (PT8) predominated . The majority of Salmonella enteritidis strains from one phage type outbreaks of Lalko presented different types of lytic reactions with the Ward phages . Only the correspondence of Salmonella enteritidis PT7 of Lalko with PT8 of Ward et al . {21} was observed.

Gesundheitswesen, 1999 May, 61(5), 241 - 7
{Investigation of foodborne outbreak due to Salmonella infantis using epidemiological and microbiological methods}; Dieckmann H et al.; In foodborne outbreaks, direct microbiological diagnosis is often not possible due to lack of remaining food samples . Therefore, in this investigation of an outbreak of Salmonella infantis at a fair, we chose an epidemiological approach in addition to microbiological testing . In a case control study, fair participants with symptoms of acute gastroenteritis as well as participants showing no signs of disease were interviewed by telephone . Questions concerning what food had been eaten at the fair and the course of disease had priority . Data analysis showed a significantly elevated odds ratio of 144 (p < 0.00001) for the consumption of potato salad . Salmonella infantis was cultured in faeces of symptomatic individuals as well as from left-over potato salad in high concentration . In conclusion, our data show that the cause of a foodborne outbreak can be detected through the application of epidemiologic methods with a high degree of certainty . In order to eliminate memory bias, a structured interview should be carried out as soon as possible after the initial outbreak.

Clin Immunol, 1999 Jul, 92(1), 76 - 89
Attenuated deltaguaBA Salmonella typhi vaccine strain CVD 915 as a live vector utilizing prokaryotic or eukaryotic expression systems to deliver foreign antigens and elicit immune responses; Pasetti MF et al.; Attenuated Salmonella typhi strain CVD 915, harboring a deletion in guaBA that interrupts the biosynthesis of guanine nucleotides, was evaluated as a live vector vaccine for delivering foreign antigens utilizing prokaryotic or eukaryotic expression systems . Plasmids pTETnir15 and pcDNA3tetC encoding fragment C (Frag C) of tetanus toxin under the control of prokaryotic or eukaryotic promoters, respectively, were introduced into CVD 915 and administered intranasally to mice . Purified pcDNA3tetC and Frag C were given intramuscularly . High titers of serum IgG1, IgG2a, and IgG2b antibodies against Frag C were elicited by CVD 915(pTETnir15) and CVD 915(pcDNA3tetC) . These responses were significantly higher than those induced by pcDNA3tetC . Proliferative responses and IL-2 and IFN-gamma production were observed in splenocytes exposed to S . typhi antigens and Frag C . We conclude that CVD 915 is a highly efficient live vector to carry foreign genes under eukaryotic or prokaryotic control and elicit potent immune responses .

Ugeskr Laeger, 1999 May 10, 161(19), 2803 - 6
{An outbreak of Salmonella enteritidis at the New Year celebration of the Copenhagen Medical Association}; Neimann BJ et al.; In order to determine the extent and infectious vehicle of an outbreak of Salmonella enteritidis phage type 6 at the New Year celebration of the Copenhagen Medical Association on 15 January 1999, a cohort study including 77 guests (90% of the participants) and 11 staff was carried out . There was little variation in the degree of exposure among the guests, meaning that identification of the probable infectious vehicle was not possible here . However, among the staff, intake of minced raw salmon was associated with increased risk of disease . Uncooked eggs were used in the preparation of this dish and since S . enteritidis phage type 6 is in Denmark almost exclusively found among egg-laying hens, these findings led to the conclusion that the outbreak was most likely caused by the use of raw eggs . The importance of notification of suspected foodborne disease and microbiological examination of people thereby exposed is stressed.

Mol Microbiol, 1999 Jul, 33(1), 74 - 83
The selC-associated SHI-2 pathogenicity island of Shigella flexneri; Moss JE et al.; Pathogenicity islands are chromosomal gene clusters, often located adjacent to tRNA genes, that encode virulence factors present in pathogenic organisms but absent or sporadically found in related non-pathogenic species . The selC tRNA locus is the site of integration of different pathogenicity islands in uropathogenic Escherichia coli, enterohaemorrhagic E . coli and Salmonella enterica . We show here that the selC locus of Shigella flexneri, the aetiological agent of bacterial dysentery, also contains a pathogenicity island . This pathogenicity island, designated SHI-2 (Shigella island 2), occupies 23.8 kb downstream of selC and contains genes encoding the aerobactin iron acquisition siderophore system, colicin V immunity and several novel proteins . Remnants of multiple mobile genetic elements are present in SHI-2 . SHI-2-hybridizing sequences were detected in all S . flexneri strains tested and parts of the island were also found in other Shigella species . SHI-2 may allow Shigella survival in stressful environments, such as those encountered during infection.

Mol Microbiol, 1999 Jul, 33(1), 63 - 73
The aerobactin iron transport system genes in Shigella flexneri are present within a pathogenicity island; Vokes SA et al.; Genes encoding the synthesis and transport of aerobactin, a hydroxamate siderophore associated with increased virulence of enteric bacteria, were mapped within a pathogenicity island in Shigella flexneri . The island, designated SHI-2 for Shigella pathogenicity island 2, was located downstream of selC, the site of insertion of pathogenicity islands in several other enteric pathogens . DNA sequence analysis revealed the presence of multiple insertion sequences upstream and downstream of the aerobactin genes and an integrase gene that was nearly identical to an int gene found in Escherichia coli O157:H7 . SHI-2 sequences adjacent to selC were similar to sequences at the junction between selC and pathogenicity islands found in E . coli O157:H7 and in enteropathogenic E . coli, but the junctions between the island and downstream yic genes were variable . SHI-2 also encoded immunity to the normally plasmid-encoded colicins I and V, suggesting a common origin for the aerobactin genes in both S . flexneri and E . coli pColV . Polymerase chain reaction and Southern hybridization data indicate that SHI-2 is present in the same location in Shigella sonnei, but the aerobactin genes are not located within SHI-2 in Shigella boydii or enteroinvasive E . coli . Shigella dysenteriae type 1 strains do not produce aerobactin but do contain sequences downstream of selC that are homologous to SHI-2 . The presence of the aerobactin genes on plasmids in E . coli pColV and Salmonella, on a pathogenicity island in S . flexneri and S . sonnei and in a different chromosomal location in S . boydii and some E . coli suggests that these virulence-enhancing genes are mobile, and they may constitute an island within an island in S . flexneri.

J Immunol Methods, 1999 Jun 24, 226(1-2), 49 - 58
Endotoxin potency in the A549 lung epithelial cell bioassay and the limulus amebocyte lysate assay; Hansen LA et al.; The purpose of this study was to elucidate to what extent the potency of endotoxins measured by the limulus amebocyte lysate (LAL) assay is reflected in the potency in an in vitro assay based on release of interleukin-8 (IL-8) from a lung epithelial cell line, A549 . Lipopolysaccharides (LPS) from Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella enteritidis and detoxified LPS from E . coli were applied in serial dilutions in the LAL assay and in the A549 bioassay . Also 19 organic dust samples from waste recycling plants were tested . The A549 cells were incubated for 24 h with LPS or dust, and the IL-8 secretion was determined by ELISA . The method for evaluation of the LAL assay showed linearity for the four endotoxins . Using the slope as a measure of the potency factor (PF), LPS from E . coli and S . enteritidis was about four times more potent than that for LPS from K . pneumoniae and P . aeruginosa . In the A549 bioassay each of the different types of endotoxin had characteristic and very different dose-response curves . The potency of the LPS, in the A549 bioassay, ranked as follows K . pneumoniae > P . aeruginosa > E . coli > or = S . enteritidis . The content of endotoxin in the dust samples did not correlate with their potency in the A549 bioassay . The present study indicates a poor correlation between the potency of endotoxin in the LAL assay compared with the A549 bioassay . The lack of correlation when organic dust samples are tested may reflect the fact that these samples contain biological active compounds, which are non-reactive in the LAL-assay but stimulate IL-8 secretion from epithelial cells.

Indian J Biochem Biophys, 1998 Oct, 35(5), 291 - 5
Spectral studies on the interaction of iodine and anthracene sulfonate with bacterial phospholipids from different mutants of Salmonella minnesota; Saha M et al.; Using spectrophotometric and spectrofluorometric techniques, the interaction of iodine and 2-anthracene sulfonate (ANS) with the phospholipids (PL) isolated from four genetically correlated Salmonella minnesota isolates viz., a smooth form (S), a deeply rough mutant (Rc) and two intermediate forms (Ra and Rb) were studied . Appearance of an isosbestic point and a new band in absorption spectra indicated charge-transfer (C-T) interaction of iodine with the PL through the formation of 1:1 complex . Stern-Volmer type fluorescence quenching of PL was observed with the addition of iodine to PL, while PL enhanced the fluorescence of anionic dye ANS . The values of the binding constants between iodine/PL and ANS/PL, measured by using suitable equations, showed a systematic gradation in the molecular properties of the PL in the membrane structure in smooth (S) and rough (Ra, Rb and Rc) mutants of Salmonella minnesota.

Klin Padiatr, 1999 Mar-Apr, 211(2), 61 - 4
The CNS symptoms of rotavirus infections under the age of two; Schumacher RF et al.; BACKGROUND: Since isolation of the Rotavirus (RV), there is rapidly growing concern about the possible involvement of RV in Central Nervous System (CNS) disorders, especially in Japan . We looked for symptomatic CNS involvement in a large series of RV infections and it's possible risk factors in a European setting . METHODS: Two-year retrospective survey based at the University Children's Hospital of Freiburg, Germany, a secondary and tertiary care centre with a urban and rural catchment area of 400,000 people . First, the case records of all 366 inpatients aged under two years excreting RV were searched for signs and symptoms of CNS involvement . Second, records of all 32 patients hospitalised with meningitis/encephalitis during the study period were checked for evidence of RV infection . RESULTS: In 15 of 366 children signs of CNS involvement (seizures, meningeal and encephalitic signs) were found . They were older (p = 0.023), had higher temperatures (p = 0.001) and CRP values (p = 0.019) . Five of the fifteen had underlying neurological diseases, two had an additional salmonella infection and one suffered from hypernatraemic toxicosis . In the remaining seven children, higher temperature (p = 0.037) and older age (p = 0.05) remained significant risk factors . CNS-signs occurred in 2% of RV-excreting children, a rate equal to the prevalence of febrile seizures among all inpatients during the study period (2.2%) . Of all 32 patients hospitalised with a diagnosis of meningitis or encephalitis only four had their stools tested for RV, all with a negative result . CONCLUSIONS: CNS symptoms in children aged less than two years with rotavirus diarrhoea have the same clinical epidemiology as febrile seizures and thus, in general, don't need additional diagnostic procedures.

EMBO J, 1999 Jul 15, 18(14), 3924 - 33
A Salmonella virulence protein that inhibits cellular trafficking; Uchiya K et al.; Salmonella enterica requires a type III secretion system, designated Spi/Ssa, to survive and proliferate within macrophages . The Spi/Ssa system is encoded within the SPI-2 pathogenicity island and appears to function intracellularly . Here, we establish that the SPI-2-encoded SpiC protein is exported by the Spi/Ssa type III secretion system into the host cell cytosol where it interferes with intracellular trafficking . In J774 macrophages, wild-type Salmonella inhibited fusion of Salmonella-containing phagosomes with lysosomes and endosomes, and interfered with trafficking of vesicles devoid of the microorganism . These inhibitory activities required living Salmonella and a functional spiC gene . Purified SpiC protein inhibited endosome-endosome fusion in vitro . A Sindbis virus expressing the SpiC protein interfered with normal trafficking of the transferrin receptor in vivo . A spiC mutant was attenuated for virulence, suggesting that the ability to interfere with intracellular trafficking is essential for Salmonella pathogenesis.

J Clin Microbiol, 1999 Aug, 37(8), 2466 - 72
Molecular typing of multiple-antibiotic-resistant Salmonella enterica serovar Typhi from Vietnam: application to acute and relapse cases of typhoid fever; Wain J et al.; The rate of multiple-antibiotic resistance is increasing among Salmonella enterica serovar Typhi strains in Southeast Asia . Pulsed-field gel electrophoresis (PFGE) and other typing methods were used to analyze drug-resistant and -susceptible organisms isolated from patients with typhoid fever in several districts in southern Vietnam . Multiple PFGE and phage typing patterns were detected, although individual patients were infected with strains of a single type . The PFGE patterns were stable when the S . enterica serovar Typhi strains were passaged many times in vitro on laboratory medium . Paired S . enterica serovar Typhi isolates recovered from the blood and bone marrow of individual patients exhibited similar PFGE patterns . Typing of S . enterica serovar Typhi isolates from patients with relapses of typhoid indicated that the majority of relapses were caused by the same S . enterica serovar Typhi strain that was isolated during the initial infection . However, some individuals were infected with distinct and presumably newly acquired S . enterica serovar Typhi isolates.

J Clin Microbiol, 1999 Aug, 37(8), 2418 - 27
Salmonella enterica serotype Dublin infection: an emerging infectious disease for the northeastern United States; McDonough PL et al.; Salmonella enterica subspecies enterica serotype Dublin (S . enterica Dublin) emerged for the first time in New York, Pennsylvania, and Ohio in 1988 . Since that time this host-adapted serotype has spread throughout the veal- and dairy beef-raising operations in the region; very few dairy farms have experienced clinical S . enterica Dublin infections . This study details the epidemiology of the outbreaks in cattle . During the period 1988 through 1995, nine New York and four Pennsylvania counties have been affected; 13 different locations were involved in New York, and 10 were involved in Pennsylvania . The morbidity and mortality and seasonal distribution of outbreaks, which totaled 35, is described . The antimicrobial susceptibility pattern of isolates revealed that many of the strains were resistant to a number of commonly used drugs . Clinical case details and pathology information are provided, with a caution to clinicians and microbiologists presented with suspect animals, i.e., most cases occurred in older calves, which is atypical for salmonellosis for this region (calves were 8 or more weeks old) and presented as pneumonia and septicemia rather than the primarily diarrheal syndrome that is more typically recognized for the region . The epidemiology of cases is analyzed through cluster analysis of bacterial isolates and their fatty acid methyl ester profiles; at least six clones appeared in the region during the study period . Results of the epidemiology analysis are used to support a hypothesis regarding the source of S . enterica Dublin for the region and its manner of dissemination.

FEBS Lett, 1999 Jun 25, 453(3), 380 - 2
Crystallization of the immunodominant outer membrane protein OmpC; the first protein crystals from Salmonella typhi, a human pathogen; Arockiasamy A et al.; OmpC, a surface antigen of Salmonella typhi was crystallized after several attempts, using PEG 3350 . Well shaped hexagonal crystals were grown from vapor diffusion method using octyl glucoside and C12E9 as detergents . Crystals are sensitive to X-ray and diffract weakly up to 7 A . Porin isoforms, due to the bound lipopolysaccharides, could be the cause for poor diffraction . Crystal quality depends largely on the purification method, and in case of LPS contamination, the genetic background of the bacteria . Crystallization and initial data collection suggest optimum conditions and the method of choice for OmpC crystallization.

Phytother Res, 1999 Jun, 13(4), 349 - 51
Antimicrobial activity of the essential oil of Calamintha nepeta and its constituent pulegone against bacteria and fungi; Flamini G et al.; The chemical composition of the essential oil of Calamintha nepeta and its antimicrobial activity against Listeria monocytogenes, Bacillus cereus, Salmonella veneziana, S . paratyphi B . S . typhimurium, Fusarium moniliforme, Botrytis cinerea, Aspergillus niger and Pyricularia oryzae have been studied . Moreover the main constituents of the oil (limonene, menthone, pulegone, menthol) have been tested against the same microorganisms . Only pulegone showed antimicrobial activity, particularly against all the Salmonella species.

J Paediatr Child Health, 1999 Jun, 35(3), 260 - 3
Chronic diarrhoea in infants and young children: causes, clinical features and outcome; Lee WS et al.; OBJECTIVES: To review the causes, clinical features and outcomes of Malaysian children who had chronic diarrhoea . METHODOLOGY: A prospective study was performed on children with diarrhoea of more than 14 days' duration who were managed at the Department of Paediatrics, University of Malaya Medical Centre, Kuala Lumpur from 1 January 1996 to 31 December 1997 . RESULTS: Twenty-seven patients (14 boys and 13 girls) were studied . The median age of onset of diarrhoea was 6 months and the mean duration of symptoms before referral was 66.5 days . The underlying causes of diarrhoea were found to be: (i) prolonged diarrhoea due to well-defined entities (intestinal lymphangiectasia, two cases; congenital glucose-galactose malabsorption, one case; post-small bowel resection, one case; (ii) postenteritis diarrhoea (cow's milk protein intolerance, eight cases; secondary lactose intolerance, four cases; transient monosaccharide intolerance, one case; (iii) gastrointestinal infections (nontyphoid Salmonella gastroenteritis, three cases; trichuriasis, two cases; amoebiasis, one case; adenovirus, one case; (iv) cases in which a firm diagnosis could not be established (three cases) . The mean duration of hospital admission was 63 days . Sixteen cases required a change in diet, while nine cases required total parenteral nutrition . One death occurred . CONCLUSIONS: Chronic childhood diarrhoea in Malaysia had a variety of aetiologies . A specific diagnosis could be established in 90% of cases . Making a diagnosis was important because this led to appropriate therapy and a good outcome in 96% of cases.

Asian Pac J Allergy Immunol, 1999 Mar, 17(1), 41 - 51
Detection of Salmonella contamination in food samples by dot-ELISA, DNA amplification and bacterial culture; Tapchaisri P et al.; A dot-blot enzyme-linked immunosorbent assay (dot-ELISA) employing a genus Salmonella specific monoclonal antibody (MAb) was used for detection of the bacteria in food samples in comparison with the conventional culture method and the DNA amplification . Among the 200 chicken and pork samples (100 each) tested, 9% and 33%, 7% and 20% and 7 and 23% were positive for salmonellae by the dot-ELISA, the culture method and the DNA amplification, respectively . Statistical analyses revealed that the sensitivity, specificity, efficacy, and positive and negative predictive values of the detection of Salmonella in the food samples by dot-ELISA compared with the culture method were 93.33%, 91.76%, 92%, 66.66% and 98.73%, respectively . Comparison of the DNA amplification and the culture method revealed the sensitivity, specificity, efficacy, and positive and negative predictive values of 100%, 91.58%, 92%, 65.21% and 100%, respectively . The dot-ELISA and the DNA amplification results were in a better agreement when the two assays were compared . The sensitivity, specificity, efficacy, positive and negative predictive values of the dot-ELISA compared to the DNA amplification were 91.3%, 100%, 98%, 100% and 97.5%, respectively . From this study, the dot-ELISA is rapid, simple, sensitive, specific at low cost with limited amount of infectious waste to be disposed and offers another advantage in that it detects only the smooth LPS of Salmonella which implies the possible presence of the virulent organisms.

Asian Pac J Allergy Immunol, 1999 Mar, 17(1), 31 - 9
Characterization of a phase 1-d epitope on Salmonella typhi flagellin and its role in the serodiagnosis of typhoid fever; Korbsrisate S et al.; A monoclonal antibody (MAb) directed against Salmonella typhi 52 kDa flagellin protein has been previously produced by our group . In this study, we have demonstrated that the epitope specific to the MAb is unique to phase 1-d . To map the epitope, plasmids encoding different regions of S . typhi flagellin gene were constructed . Analysis of protein produced from each recombinant plasmid indicated that the epitope specific to the MAb resided within amino acids 171-303 (region IV) of S . typhi flagellin protein . The recombinant region IV flagellin was used to develop an ELISA for the detection of IgM antibody to S . typhi in serum . In the hemoculture-positive typhoid group, the developed ELISA was positive in 77 of 92 cases . In patients with non-typhoidal Salmonella, gram-positive and gram-negative bacteria or dengue virus, the ELISA was negative in all 78 cases . Two from 116 healthy control subjects had positive reactions with the assay . The calculated sensitivity, specificity, positive and negative predictive values of the test were 83.7%, 99.0%, 97.5% and 92.8%, respectively . With such high validity together with the requirement of only a single serum specimen and one day for performing the test, the developed ELISA should become a valuable diagnostic test for typhoid fever.

Ugeskr Laeger, 1999 Jun 28, 161(26), 4010 - 1
{Vascular prosthesis infected with Salmonella . A rare complication of Salmonella sepsis}; Andersen PJ et al.; A case of vascular graft infection secondary to Salmonella septicaemia is described . The patient was a 69 year old man with an aortic bifurcation graft and a femoropopliteal bypass . Despite antibiotics treatment, operation was necessary . An especially long extra-anatomical bypass was used.

Przegl Epidemiol, 1999, 53(1-2), 83 - 91
{Salmonellosis in 1997}; Gonera E; The gradual decline of number salmonellosis cases has observed since 1988 . In 1997, 23,206 cases of salmonellosis were reported to the sanitary epidemiological stations in the whole country . Incidence rate was 60 per 100,000 inhabitants and was lower than 1996 and median 1991-1995 rates . Most of cases (19,611) was confirmed by isolation of Salmonella strains . The prevalent serotypes distributed at least in 30 of 49 voivodships, were: S . enteritidis (90% of all cases), S . typhimurium --3%, S . infantis--1.3%, S . virchow--1.2% and S . hadar--1% . Rates were highest in children aged under five years . The most serious clinical syndromes and complications were seen in the 49 oldest patients above 50 years old (septicaemia, meningitis, arthritis, osteomyelitis and abscesses) . Five of them had died.

J Korean Med Sci, 1999 Jun, 14(3), 342 - 4
Non-typhoid Salmonella meningitis complicated by a infarction of basal ganglia; Kim H et al.; A previously healthy 16-month-old Korean girl with symptoms of fever, vomiting, and generalized tonic seizure was diagnosed to have Group D non-typhoid Salmonella meningitis . The patient was treated with ceftriaxone (100 mg/kg/day) and amikin (22.5 mg/kg/day) initially and ciprofloxacin (30 mg/kg/day) was added later because of clinical deterioration and disseminated intravascular coagulation . Brain CT performed on the second day showed a well-demarcated low density lesion in the right lentiform nucleus and both caudate nuclei, without evidence of increased intracranial pressure . MRI performed on the 11th day confirmed CT scan findings as well as right subdural fluid collection, brain atrophy, and ventriculomegaly . She underwent subdural drainage and later ventriculo-peritoneal shunt operation . Despite receiving intensive treatment, she still has severe neurologic sequelae . Our case shows that infarctions of basal ganglia and thalami are not specific for tuberculous meningitis and that meningitis complicated by infarction is indicative of grave prognosis.

J Bacteriol, 1999 Jul, 181(14), 4275 - 84
Characterization of the serogroup O11 O-antigen locus of Pseudomonas aeruginosa PA103; Dean CR et al.; We previously cloned a genomic DNA fragment from the serogroup O11 Pseudomonas aeruginosa strain PA103 that contained all genes necessary for O-antigen synthesis and directed the expression of serogroup O11 antigen on recombinant Escherichia coli and Salmonella . To elucidate the pathway of serogroup O11 antigen synthesis, the nucleotide sequence of the biosynthetic genes was determined . Eleven open reading frames likely to be involved in serogroup O11 O-antigen biosynthesis were identified and are designated in order as wzzPaO111 (wzz from P . aeruginosa serogroup O11), wzxPaO11, wbjA, wzyPaO11, wbjB to wbjF, wbpLO11 and wbpMO11 (wbpL and wbpM from serogroup O11) . Consistent with previous descriptions of O-antigen biosynthetic gene loci, the entire region with the exception of wbpMO11 has a markedly reduced G+C content relative to the chromosomal average . WzyPaO11 shows no significant similarity at the protein or DNA sequence level to any database sequence and is very hydrophobic, with 10 to 12 putative transmembrane domains, both typical characteristics of O-antigen polymerases . A nonpolar chromosomal insertion mutation in wzyPaO11 in P . aeruginosa PA103 confirmed the identity of this gene . There is striking similarity between WbjBCDE and Cap(5/8)EFGL, involved in type 5 and type 8 capsule biosynthesis in Staphylococcus aureus . There is nearly total identity between wbpMO11 and wbpMO5, previously shown by others to be present in all 20 P . aeruginosa serogroups . Using similarity searches, we have assigned functions to the proteins encoded by the PA103 O-antigen locus and present the potential steps in the pathway for the biosynthesis of P . aeruginosa serogroup O11 O antigen.

Med Trop (Mars), 1998, 58(4), 403 - 7
{Pleuropulmonary manifestations of salmonellosis}; Hovette P et al.; Salmonella infections are widespread particularly in tropical zones . Each year, 12.5 million cases of typhoid fever are reported with an incidence of 540 cases for every 100,000 inhabitants in developing countries versus 0.2 cases in industrialized countries . Pleuropulmonary manifestations constitute the most common extra-intestinal manifestation of salmonella infection . Counts are usually carried out in the digestive tract . Respiratory tract manifestations result from blood-borne diffusion from mesenteric lymph nodes, but gastroenteritis goes unnoticed in 2 of 3 cases . Predisposing factors are frequent including cancer, previous graft placement and immunosuppressant therapy, sickle cell disease, alcohol abuse, and pre-existing pulmonary disease . Clinical manifestations are usually acute but subacute forms cannot be ruled out . Cough is a common symptom observed in 25% of patients with typhoid fever . Pneumonia is uncommon overall (1%) but occurs in 50% of patients with pleural effusion, empyema, lung abscess, or bronchopleural fistula . A few cases of adult respiratory distress syndrome have been described in the literature . Recognition is important since these manifestations may signal previously unsuspected underlying pulmonary disease . Treatment requires appropriate antimicrobial therapy and close surveillance to prevent recurrence or complications.

Immunol Rev, 1999 Apr, 168, 241 - 55
Type III secretion machines and the pathogenesis of enteric infections caused by Yersinia and Salmonella spp; Lee VT et al.; Salmonella and Yersinia spp . infect the intestinal tract of humans . Although these organisms cause fundamentally different diseases, each pathogen relies on type III secretion machines to either inject virulence factors into the cytosol of eukaryotic cells or release toxins into the extracellular milieu . Type III secretion machines are composed of many different subunits and export several polypeptides with unique substrate requirements . During Salmonella pathogenesis, the type III machine encoded by the Salmonella pathogenicity island (SPI)-1 genetic element functions to cause invasion of the intestinal epithelium, whereas another type III machine (SPI-2) is required for survival in macrophages . Yersinia enterocolitica and Yersinia pseudotuberculosis employ type III machines to resist macrophage phagocytosis and to manipulate the host's immune response, thereby colonizing intestinal lymphoid tissues . We describe what is known about the pathogenic functions of virulence factors secreted by type III machines . Furthermore, type III secretion machines may be exploited for the injection of recombinant proteins, a strategy that has already been successfully employed to elicit a cell-mediated immune response.

Clin Microbiol Rev, 1999 Jul, 12(3), 405 - 28
Molecular basis of the interaction of Salmonella with the intestinal mucosa; Darwin KH et al.; Salmonella is one of the most extensively characterized bacterial pathogens and is a leading cause of bacterial gastroenteritis . Despite this, we are only just beginning to understand at a molecular level how Salmonella interacts with its mammalian hosts to cause disease . Studies during the past decade on the genetic basis of virulence of Salmonella have significantly advanced our understanding of the molecular basis of the host-pathogen interaction, yet many questions remain . In this review, we focus on the interaction of enterocolitis-causing salmonellae with the intestinal mucosa, since this is the initiating step for most infections caused by Salmonella . Animal and in vitro cell culture models for the interaction of these bacteria with the intestinal epithelium are reviewed, along with the bacterial genes that are thought to affect this interaction . Lastly, recent studies on the response of epithelial cells to Salmonella infection and how this might promote diarrhea are discussed.

Environ Mol Mutagen, 1999, 33(4), 303 - 12
Genotoxicity of complex PAH mixtures recovered from contaminated lake sediments as assessed by three different methods; Randerath K et al.; Although human exposure generally occurs to mixtures of chemicals, limited toxicological information is available to characterize the potential interactions of the components of environmental mixtures . This study was conducted to compare the genotoxicity of chemically characterized polycyclic aromatic hydrocarbon (PAH) mixtures using in vitro and in vivo techniques . A total of three extracts (E1-E3) were selected from sediment samples collected from a lake adjacent to an abandoned coal gasification site . Sediments were collected on a grid moving downstream and away from the most likely source of PAH contamination, with E1 collected closest to the shore, E2 at an intermediate distance, and E3 furthest from the shore . The sediment samples were extracted in methylene chloride and methanol, dried, and redissolved in an appropriate solvent for evaluation in a battery of genotoxicity assays . Samples were evaluated for their ability to produce point mutations in bacteria and DNA adducts in vitro without metabolic activation or in vivo . Samples were also analyzed using GC/MS . Sample E1 had both the highest concentration of benzo(a)pyrene (BP) (46.5 ppm) and carcinogenic PAHs and, using 32P-postlabeling, induced the highest adduct levels overall in vitro and in vivo . Sample E2, which had a BP concentration of 14 ppm, induced the greatest number of revertants in the bacterial mutagenicity assay . Sample E3, which had the lowest level of carcinogenic PAHs and BP, induced the lowest adduct levels . However, E3 was capable of inducing a positive genotoxic response in bacteria (with S9), although the slope of the response at lower doses was less than that of E2 . The in vivo data showed that the major adduct formed by E1 and E2 was a BP adduct . This information could not have been obtained with the Salmonella or in vitro postlabeling tests . Among internal organs, the extracts of all three samples induced the greatest adduct levels in the lung, similarly to previous complex PAH mixtures studied . These data demonstrate the limitations of predicting genotoxic or carcinogenic potential based on chemical analysis or a single biological test . The results suggest that mixture interactions, cytotoxicity and metabolism are likely to have an influence on the potential of a complex mixture of chemicals to produce a carcinogenic effect . In addition, the concentration of genotoxic PAHs and both in vitro and in vivo DNA adduct formations were decreased with increasing distance from the shoreline .

Avian Dis, 1999 Apr-Jun, 43(2), 302 - 9
Contamination of Salmonella blockley in the environment of a poultry farm; Limawongpranee S et al.; Cecal and environmental samples were collected and examined for the presence of Salmonella on a farm where a high prevalence of Salmonella blockley in chickens was observed . Of 895 cecal and 525 environmental samples examined, 242 (27.0%) and 202 (38.5%) samples, respectively, yielded S . blockley . From the analysis of plasmid profile patterns, 11 different plasmid profile patterns were found among 444 isolates, with plasmid patterns c and d the most frequent among the isolates from ceca and the environment . Salmonella blockley was isolated from environmental samples such as floor litter, walls, drinking water, waste water, dust, and soil collected when barns were occupied and was positive in drinking water, waste water, and soil when samples were collected from empty barns with occupied neighboring barns, but it was negative in all environmental samples with the exception of soil when the environmental samples were collected from empty barns with empty neighboring barns.

J Mol Biol, 1999 Jul 16, 290(3), 741 - 56
Structural predictions of AgfA, the insoluble fimbrial subunit of Salmonella thin aggregative fimbriae; Collinson SK et al.; The unusually stable and multifunctional, thin aggregative fimbriae common to all Salmonella spp . are principally polymers of the fimbrin subunit, AgfA . AgfA of Salmonella enteritidis consists of two domains: a protease-sensitive, 22 amino acid residue N-terminal region and a protease-resistant, 109 residue C-terminal core . The unusual amino acid sequence of the AgfA core region comprises two-, five- and tenfold internal sequence homology patterns reflected in five conserved, 18-residue tandem repeats . These repeats have the consensus sequence, Sx5QxGx2NxAx3Q and are linked together by four or five residues, (x)xAx2 . The predicted secondary structure for this unusual arrangement of tandem repeats in AgfA indicates mainly extended conformation with the beta strands linked by four to six residues . Candidate proteins of known structure with motifs of alternating beta strands and short loops were selected from folds described in SCOP as a source of coordinates for AgfA model construction . Three all-beta class motifs selected from the Serratia marcescens metalloprotease, myelin P2 protein or vitelline membrane outer protein I were used for initial AgfA homology build-up procedures ultimately resulting in three structural models; beta barrel, beta prism and parallel beta helix . The beta barrel model is a compact, albeit irregular structure, with the beta strands arranged in two antiparallel beta sheet faces . The beta prism model does not reflect the 5 or 10-fold symmetry of the AgfA primary sequence . However, the favored, parallel beta helix model is a compact coil of ten helically arranged beta strands forming two parallel beta sheet faces . This arrangement predicts a regular, potentially stable, C-terminal core region consistent with the observed tandem repeat sequences, protease-resistance and strong tendency of this fimbrin to oligomerize and aggregate . Positional conservation of amino acid residues in AgfA and the Escherichia coli AgfA homologue, CsgA, provides strong support for this model . The parallel beta helix model of AgfA offers an interesting solution to a multifunctional fimbrin molecular surface having solvent exposed areas, regions for major and minor subunit interactions as well as fiber-fiber interactions common to many bacterial fimbriae .

J Nutr, 1999 Jul, 129(7), 1382 - 9
High intake of milk fat inhibits intestinal colonization of Listeria but not of Salmonella in rats; Sprong RC et al.; During fat digestion, fatty acids and monoglycerides are liberated in the gastrointestinal tract . Generally, these lipids are potent inhibitors of gram-positive bacteria in vitro but have less effect on gram-negative microbes . Considering this, we hypothesized that increased intake of bovine milk fat would result in enhanced gastrointestinal killing of Listeria monocytogenes (gram-positive) but have little effect on infection with Salmonella enteritidis (gram-negative) in rats . To test this, rats were fed either low milk fat diets (10% of energy obtained from milk fat, corresponding to 4 . 2 g fat/100 g diet) or high milk fat diets (40% of energy obtained from milk fat, corresponding to 19.6 g fat/100 g diet) . After adaptation to these diets, rats were orally infected with Listeria or Salmonella . Greater milk fat consumption in Listeria-infected rats diminished intestinal colonization of Listeria (P < 0.05) and reduced diarrhea (P < 0.05) . Analysis of gastrointestinal contents showed that killing of Listeria occurred predominantly in the stomach . High milk fat intake significantly augmented this gastric listericidal capacity (P < 0.05) and raised the concentration of medium-chain and saturated long-chain free fatty acids and of monoglycerides of C12:0, C14:0, C16:0, C18:0, and C18:1 in gastric chyme (P < 0.05) . Considering the in vitro listericidal capacity of these agents, it was concluded that particularly the free fatty acids C10:0, C12:0 and C14:0 and the monoglycerides of C12:0, C14:0, and C16:0 seem to play a pivotal role in this enhanced Listeria killing . In contrast, Salmonella infection was not affected by milk fat consumption . In conclusion, high milk fat intake results in higher concentrations of gastric bactericidal lipids and thereby protects against Listeria infection but not against Salmonella.

J Microbiol Methods, 1999 Jul, 37(1), 87 - 91
Automated detection of Salmonella spp . in foods; Tan W et al.; An automated method to detect salmonellae in foods was developed and tested in food samples intentionally contaminated with the test organisms . Liquid eggs, shell eggs, dry eggs, skim milk and chicken were spiked with Salmonella enteritidis, S . typhimurium or S . newport to yield 2 to 25 CFU per 25 g or ml of sample . Following pre-enrichment in universal pre-enrichment broth at 42 degrees C for 6 h (eggs and milk) or 16 h (chicken), Salmonella cells were captured by immunomagnetic beads coated with Salmonella antibody (Vicam, Watertown, MA) . The beads were transferred to selective liquid media containing carbohydrate (dulcitol or xylose), amino acid (lysine or ornithine), and H2S indicator, and incubated at 42 degrees C in the BioSys instrument (MicroSys, Ann Arbor, MI) . Salmonella positive samples were identified by black discoloration of the media during incubation, while negative samples remained colorless . These color changes were recorded by the instrument . All the artificially contaminated samples tested positive within 15-18 h, while control samples remained negative during 24 h incubation . The results agreed with standard identification procedures . A total of 24 h was required to detect 2 to 25 CFU of the pathogen in 25 g or ml of eggs and milk, and up to 36 h in chicken, compared to 72 h in the standard methods.

Chemotherapy, 1999 Jul-Aug, 45(4), 268 - 76
Killing of gram-negative bacteria by ciprofloxacin within both healthy human neutrophils and neutrophils with inactivated O2-dependent bactericidal mechanisms; Canton E et al.; The intraphagocytic killing of Escherichia coli, Serratia marcescens, Pseudomonas aeruginosa, and Salmonella typhi by ciprofloxacin (0.1, 1 and 5 microg/ml) within human neutrophils with intact and impaired (by phenylbutazone treatment) O2-dependent killing mechanisms was studied and compared with the extracellular killing in the same medium of the intraphagocytic killing, but omitting neutrophils . The MIC/MBC of ciprofloxacin in vitro (assays performed according to NCCLS specifications) were: 0.015/0.06 for E . coli, 0.12/32 for S . marcescens, 1/16 for P . aeruginosa, and 0.007/0.06 for S . typhi . Ciprofloxacin showed bactericidal activity both extracellular and within phenylbutazone-treated and untreated neutrophils . The minimum concentration of ciprofloxacin to kill 90% of phagocytosed bacteria within neutrophils with normal O2-dependent killing power after 30 min was: 0.1 microg/ml for E . coli, and S . typhi, 1 microg/ml for P . aeruginosa, and 5 microg/ml for S . marcescens . In contrast, exposure for 60 min was required to reach this percentage within phenylbutazone treated neutrophils . The minimum concentration to kill 90% of extracellular bacteria after 30 min was: 0.1 microg/ml for E . coli, P . aeruginosa and S . typhi, and 5 microg/ml, for S . marcescens . A positive interaction between ciprofloxacin and the O2-dependent mechanisms of phagocytes was found . The reactive oxygen metabolites produced in the respiratory burst did not affect the intraphagocytic activity of ciprofloxacin . Phenylbutazone treatment of phagocytes would be a good experimental model to study the intraphagocytic killing of drugs in situations such as AIDS and chronic granulomatous disease where inefficient oxidative mechanisms of neutrophils exist.

Mutagenesis, 1999 Jul, 14(4), 365 - 73
Cytosol is required for the modulation by dietary casein of the hepatic microsomal activation of aflatoxin B1 to mutagenic metabolites detectable in Salmonella; Woodall GM Jr et al.; We have shown previously that dietary protein (casein) levels can affect the ability of rat liver S9 to metabolize aflatoxin B1 (AFB) as well as other promutagens detectable in Salmonella strain TA98 {Mutat . Res . (1997), 360, 115-126 and 127-143} . The mutagenic potency of AFB was greatest when metabolized by the Aroclor 1254-induced hepatic S9 prepared from F344 male rats that consumed an isocaloric, semisynthetic diet for 6 weeks that contained an adequate (12%) level of methionine-supplemented casein as the sole protein source, compared with S9s from rats fed diets that contained nominally deficient (8%) or high (22%) levels of casein . Here we have extended this observation by performing (i) mutagenicity studies with microsomes, cytosols and reconstituted S9s (recombinations of microsomes and cytosols across dietary groups), and (ii) in vitro incubations followed by analysis of metabolites by fluorescence high-pressure liquid chromatography . Microsomes, but not cytosols, activated AFB; however, activation to the level observed with S9 occurred only when microsomes from the rats fed 12% casein were combined with cytosols from any dietary group . Consistent with the mutagenicity results, the greatest metabolism of the AFB parent compound and the highest level of the glutathione conjugate of the presumptively identified AFB-exo-8,9-epoxide (the ultimate mutagenic form of AFB) were produced by S9s from the rats fed the 12% casein diet . The levels of these metabolites and the mutagenicity of AFB changed in parallel with changes in dietary casein levels . In summary, cytosolic elements, which are not affected by dietary casein levels, interact with microsomal enzymes, which are modulated by dietary casein levels, to influence the ability of hepatic S9 to activate AFB to a mutagen.

Int J Antimicrob Agents, 1999 Jun, 12(1), 47 - 52
In vitro evaluation of intracellular activity of antibiotics against non-typhoid Salmonella; Chiu CH et al.; Non-typhoid salmonellae are the most common causative organisms of bacterial enteritis in children . Clinical studies have failed to show any influence of various antibiotics on the natural course of acute salmonella enteritis . Poor penetration of antibiotics into phagocytic cells that contain intracellular Salmonella spp., and possible intracellular antibiotic inactivation have been considered as possible reasons for this . In this study, we used an in vitro model to assess the intracellular activity of antibiotics against non-typhoid salmonellae . The survival of intracellular Salmonella spp . in P388D1 cells, a mouse macrophage cell line was measured in the presence of various antibiotics . Except for gentamicin, which entered phagocytes poorly, ofloxacin, azithromycin, chloramphenicol and three beta-lactam antibiotics, ampicillin, cefixime and ceftriaxone, exhibited bacteriostatic activity against susceptible intracellular Salmonella spp . at an extracellular concentration equal to the minimal inhibitory concentration (MIC) . At a concentration of 10 x MIC, neither chloramphenicol nor the three beta-lactam antibiotics produced a bactericidal response; however, both ofloxacin and azithromycin were bactericidal after 8-24 h of incubation . The results showed that fluoroquinolones and new macrolides were more efficient than the other antibiotics in eradicating intracellular salmonella and might be useful agents for the treatment of non-typhoid salmonella enteritis in children . Clinical trials should be considered.

Kansenshogaku Zasshi, 1999 May, 73(5), 437 - 44
{Biochemical and molecular characterization of Salmonella ser . enteritidis phage type 1 isolated from food poisoning outbreaks in Tokyo}; Kusunoki J et al.; Since the first outbreak in 1990, the incidence of Salmonella ser . Enteritidis (S . Enteritidis) phage type (PT) 1 food poisoning has gradually increased in Tokyo and has reached approximately 30% of the total S . Enteritidis outbreaks reported . To characterise these S . Enteritidis PT1 food poisoning, a total of 198 strains obtained from 44 outbreaks between 1990 and 1996 were examined for antimicrobial resistance, acid producibility from glycols (propylene and ethylene glycol) and plasmid DNA profiles . The 44 PT1 outbreaks analysed were further subdivided into 11 types by epidemiological markers . The most common patterns were type A (plasmid profile carrying only one plasmid (60 kb) . SM and TC resistance and non producibility from glycols), and type B (plasmid profile carrying two plasmids (60 and 20 kb), SM resistance and no producibility from glycols) and were responsible for 21 (47.7%) and 15 (34.1%) outbreaks, respectively . In 11 of 44 outbreaks, strains carrying identical epidemiological markers were isolated both from patients and vehicle foods, environments, and/or food-handlers . Similar to PT4 and PT34 outbreaks reported in Japan, egg and egg-related foods were also suspected in 8 of these 11 outbreaks . Of interest, chicken which were not pointed out in PT4 and PT 34 outbreaks was also suspected as a vehicle of transmission in two outbreaks.

Microbiol Immunol, 1999, 43(4), 351 - 7
TTG as the initiation codon of Salmonella slyA, a gene required for survival within macrophages; Kawakami T et al.; The slyA gene, which has been implicated in the virulence of Salmonella serovar Typhimurium and its survival in macrophages, is widely distributed among different Salmonella serovars . In this study, we cloned and sequenced the translational initiation region of the slyA gene from nine different serovars and found sequence differences in the previously proposed ATG initiation codon but not in a TTG triplet, another putative initiation codon in the slyA gene . Therefore, we determined the actual translational initiation site of the slyA gene by analyzing slyA genes with defined mutation in either the ATG or TTG sequences in an in vitro translation assay and a quantitative hemolytic assay in Escherichia coli . The replacement of TTG by TTC in the slyA gene significantly reduced both the amount of protein synthesized and the hemolytic activity of a transformed strain of E . coli, while replacement of ATG by ATC had no effect in these assays . In addition, the amino acid sequence analysis of the His-tagged SlyA protein showed that it was identical with the amino acid sequence deduced from the 5' end of the slyA gene with a TTG initiation codon . Our results suggest that TTG serves as the translational initiation codon for the slyA gene of Salmonella.

Vet Microbiol, 1999 May, 66(4), 285 - 90
A Salmonella abortusovis inactivated vaccine protects mice from abortion after challenge; Giannati-Stefanou A et al.; Two types of Salmonella abortusovis vaccines were prepared, one with aluminium hydroxide (vaccine A) and the other with water in oil (vaccine B) adjuvants . They were compared in a pregnant mouse model, aiming at protecting them from abortions after challenge with a virulent strain of S . abortusovis . The protection for vaccine A was from 74% to 77.6% and that for vaccine B from 71% to 79.6% . Abortions occurred 5-10 days post challenge and S . abortusovis was isolated from all aborted fetuses and from the liver and the spleen of their mothers at the end of the experiment (18 days post challenge) . The presence of salmonella in the liver and the spleen of vaccinated non-pregnant but challenged mice was studied in a separate experiment . The bacterium was isolated from one out of 12 vaccinated mice 6 days post challenge as well as from the six controls.

Int Immunol, 1999 Jul, 11(7), 1043 - 51
Intranasal administration of peptide vaccine protects human/mouse radiation chimera from influenza infection; Ben-Yedidia T et al.; Influenza virus is characterized by frequent and unpredictable changes of the surface glycoproteins which enable the virus to escape the immune system . Approved vaccines which consist of the whole virus or the surface glycoproteins fail to induce broad specificity protection . We have previously reported that a peptide-based experimental recombinant vaccine which includes conserved epitopes of B and T lymphocytes was efficient in mice, leading to cross-strain, long-term protection . In the present study, this approach was adapted for the design of a human vaccine, based on epitopes recognized by the prevalent HLAs . These epitopes were expressed in Salmonella flagellin and tested for their efficacy in human/mouse radiation chimera in which human peripheral blood mononuclear cells (PBMC) are functionally engrafted . The vaccinated mice demonstrated clearance of the virus after challenge and resistance to lethal infection . The production of virus-specific human antibodies was also higher in this group . Control groups of either non-vaccinated, or vaccinated mice which had not been engrafted with the human PBMC, did not exhibit the protective immune response . FACS analysis showed that most human cells in the transplanted mice are CD8(+) and CD4(+) . Hence, it may be concluded: (i) that the protection involves cellular mechanisms, but is most probably accomplished without direct lysis of influenza-infected pulmonary cells by cytotoxic T lymphocytes, but rather via a cytokine-mediated mechanism, (ii) that the human/mouse radiation chimera model may be of some value in the investigation of new vaccines, as an additional tool prior to clinical trials, and (iii) that the synthetic recombinant vaccine can induce a response in the human immune system and confers protection against influenza infection . Further investigation is needed to establish the efficacy of such a peptide vaccine in human subjects.

Carcinogenesis, 1999 Jul, 20(7), 1303 - 7
New studies on trans-anethole oxide and trans-asarone oxide; Kim SG et al.; The widespread use of naturally occurring alkenylbenzenes as flavoring and fragrance agents has led to a long-standing interest in their toxicity and carcinogenicity . Among them several allyl- and propenylbenzenes have been found to be mutagenic and carcinogenic . It has been shown that the carcinogenicity of several allylbenzenes can be related to the formation of electrophilic sulfuric acid esters following 1'-hydroxylation . Unlike the allylbenzenes, the mechanisms of carcinogenesis of propenylbenzenes such as anethole and asarone are not clear . It has been reported that one of the main metabolic pathways of trans-anethole is the epoxidation of the side chain 1,2-double bond, which was responsible for cytotoxicity but not for genotoxicity . However, we report here that synthetic trans-anethole oxide prepared from trans-anethole and dimethyldioxirane is not only mutagenic for Salmonella tester strains but is also carcinogenic in the induction of hepatomas in B6C3F1 mice and skin papillomas in CD-1 mice . Synthetic trans-asarone oxide was also carcinogenic in the induction of hepatomas as well as mutagenic for Salmonella strains . Further studies are needed on these side chain oxides of trans-anethole and trans-asarone as possible metabolites in the toxicity, mutagenicity and carcinogenicity of these and other propenylbenzenes.

J Food Prot, 1999 Jun, 62(6), 662 - 4
Detection and isolation of Salmonella from naturally contaminated alfalfa seeds following an outbreak investigation; Inami GB et al.; Naturally contaminated alfalfa seeds, epidemiologically linked to foodborne disease outbreaks in Oregon and British Columbia, were tested for the presence of Salmonella . Ten sample units from the suspected lot were sprouted and grown for 4 days . After enrichment of the grown sprouts, an enzyme immunoassay (EIA) and culture method (modified procedure of the Food and Drug Administration Bacteriological Analytical Manual) were used for the detection and isolation of Salmonella . Four of the 10 sample units were positive with the EIA; however, 5 of the 10 sample units were culture positive (four were positive for Salmonella serotype Newport and a fifth was positive for Salmonella serotype Albany and serotype Schwarzengrund) . The positive alfalfa seed sample units were further tested after shredding, soaking, and washing before culturing . Results suggest that sprouting and shredding methods may yield greater detection and recovery rates of Salmonella, but more research with a larger sample size is warranted.

J Food Prot, 1999 Jun, 62(6), 585 - 91
Rapid growth of Salmonella enteritidis in egg white reconstituted from industrial egg white powder; Baron F et al.; The aim of this study was to evaluate the consequences of the egg white-drying process on egg white ability to limit Salmonella Enteritidis growth in addition to the elucidation of the factors involved . We observed rapid growth of Salmonella Enteritidis inoculated in egg white reconstituted from industrial powder in comparison with that observed in liquid egg white collected in the laboratory: Salmonella cell counts rose from 10(3) to 10(8) cells/ml of egg white from powder during 24 h incubation at 30 degrees C . This rapid growth was observed in powder from all egg-breaking factories investigated, and it was comparable to that observed in optimum medium (tryptone soy broth) . In view of the mechanism of egg white resistance and the major role played by iron availability and by ovotransferrin, we investigated several hypotheses to explain this rapid growth: iron provided during the drying process and/or denaturation of protein (especially ovotransferrin) . The rapid growth observed in egg white reconstituted from powder was in relation to egg white protein denaturation and especially ovotransferrin denaturation during powder pasteurization that enhanced the availability of iron necessary for Salmonella growth . The major role played by ovotransferrin and iron deficiency on Salmonella growth in egg white was illustrated in this study.

Semin Immunol, 1999 Jun, 11(3), 193 - 203
M cells as ports of entry for enteroinvasive pathogens: mechanisms of interaction, consequences for the disease process; Sansonetti PJ et al.; M cells are key sites of antigen sampling for the mucosal-associated lymphoid system (MALT) and consequently are essential components of the structures serving as inductive sites for mucosal immunity . In addition, they have recently been recognized as major sites of adherence and major ports of entry for enteric pathogens . In the case of enteroinvasive pathogens, such as Salmonella, Yersinia and Shigella, few clinical evidences, but lots of experimental data indicate that, at least at the early stage of infection, M cells of the follicular associated epithelium transport the pathogens . This has significantly altered our view on the pathogenesis of enteroinvasive infections . Crossing the epithelial barrier seems an achievable task for these bacteria which express adherence and invasion mechanisms which have often been well characterized in epithelial cell lines . These systems seem to be also used for entering and crossing M cells, although reproducible in vitro assays for M cell infection are now required . Having crossed the epithelial lining, the bacteria face phagocytic cells, particularly the macrophages that are present in the follicle dome . Depending on the capacity to survive in the presence of macrophages, and how this survival is achieved by a given invasive species, the outcome of infection can be dramatically affected . In consequence, M cells can be considered as pathogen translocators toward immunocompetent areas of the gut, thus opening the possibility to harness this property in order to design new mucosal vaccines or vaccine vectors .

J Antimicrob Chemother, 1999 Jan, 43(1), 145 - 8
Increasing fluoroquinolone resistance in salmonella serotypes in Finland during 1995-1997; Hakanen A et al.; Antimicrobial resistance trends were examined for 811 salmonella isolates from humans collected in Finland during 1995-1997 . The material was divided into domestic and foreign isolates according to the origin of infection . A total of 2.3% of the 387 domestic and 7.8% of the 424 foreign isolates were quinolone-resistant (P < 0.001) . Among the domestic isolates we detected an emergence of ciprofloxacin resistance (MIC > or = 0.25 mg/L) with the proportion of resistant isolates increasing from 0 to 2.2% (P = 0.2) . Among the foreign isolates this increase was even more dramatic, from 2.0% to 8.4% (P = 0.037) during the study period.

Infection, 1999 May-Jun, 27(3), 224 - 7
Spontaneous non-typhoidal Salmonella peritonitis in patients with serious underlying disorders; de la Fuente-Aguado J et al.; Non-typhoidal Salmonella is a rare cause of spontaneous bacterial peritonitis (SBP) . Non-typhoidal Salmonella SBP has been reported in patients with relatively normal ascitic fluid protein levels . Five patients with non-typhoidal Salmonella SBP and a review of the literature are reported . These patients had chronic underlying disorders, such as malignancy, or other conditions causing immunosuppression . In previous reports, an ascitic fluid protein level above 1.5 g/dl was present in six patients, and under 1.5 g/dl in two . In the present report, ascitic fluid protein is above 2.5 g/dl in three patients and under 1.5 g/dl in one . Immunosuppression and the virulence of the organism seem to play a major role in non-typhoidal Salmonella SBP . Physicians should be alert to the possibility of non-typhoidal Salmonella infection in patients with SBP and normal protein levels in ascitic fluid.

Chemosphere, 1999 Jul, 39(1), 33 - 43
Genotoxicity of organic extracts of airborne particles in somatic cells of Drosophila melanogaster; Delgado-Rodriguez A et al.; Complex mixtures extracted from air filters exposed for 24 h in two sessions (27 July and 02 August 1991) and at two locations (Merced, downtown, and Pedregal de San Angel, south-west) in Mexico City were analysed . The organic extracts were from airborne particles equal or smaller than 10 microns (PM10), and from total suspended particles (TSP) . These organic extracts were assayed in the somatic mutation and recombination test (SMART) in wings of Drosophila melanogaster using two different crosses as well as in the Salmonella/microsome assay using strain TA98 with and without S9 fraction . The presence of polycyclic aromatic hydrocarbons (PAH) in the extracts was determined by gas chromatography . The genotoxic activities observed in the two test systems were comparable with the indirect mutagens producing greater response than the direct mutagens . The quantities of particulate matter as well as the genotoxic activities were higher on 02 August than on 27 July 1991 for both locations . The amounts of airborne particles and the resulting genotoxic activities were higher at Merced than at Pedregal . In both biological systems, PM10 were more genotoxic than TSP . These results demonstrate the sensitivity of the Drosophila wing SMART-which is an in vivo eukaryotic genotoxicity assay-as a biological monitor of environmental pollution related to airborne particles.

Infect Immun, 1999 Jul, 67(7), 3680 - 5
Mucosal and systemic immune responses in humans after primary and booster immunizations with orally administered invasive and noninvasive live attenuated bacteria; Viret JF et al.; The mucosal and systemic immune responses after primary and booster immunizations with two attenuated live oral vaccine strains derived from a noninvasive (Vibrio cholerae) and an invasive (Salmonella typhi) enteric pathogen were comparatively evaluated . Vaccination with S . typhi Ty21a elicited antibody-secreting cell (ASC) responses specific for S . typhi O9, 12 lipopolysaccharide (LPS), as well as significant increases in levels of immunoglobulin G (IgG) and IgA antibodies to the same antigen in serum . A strong systemic CD4(+) T-helper type 1 cell-mediated immune (CMI) response was also induced . In contrast to results with Ty21a, no evidence of a CMI response was obtained after primary immunization with V . cholerae CVD 103-HgR in spite of the good immunogenicity of the vaccine . Volunteers who received a single dose of CVD 103-HgR primarily developed an IgM ASC response against whole vaccine cells and purified V . cholerae Inaba LPS, and seroconversion of serum vibriocidal antibodies occurred in four of five subjects . Serum IgG anti-cholera toxin antibody titers were of lower magnitude . For both live vaccines, the volunteers still presented significant local immunity 14 months after primary immunization, as revealed by the elevated baseline antibody titers at the time of the booster immunization and the lower ASC, serum IgG, and vibriocidal antibody responses after the booster immunization . These results suggest that local immunity may interfere with colonization of the gut by both vaccine strains at least up to 14 months after basis immunization . Interestingly, despite a low secondary ASC response, Ty21a was able to boost both humoral (anti-LPS systemic IgG and IgA) and CMI responses . Evidence of a CMI response was also observed for one of three volunteers given a cholera vaccine booster dose . The direct comparison of results with two attenuated live oral vaccine strains in human volunteers clearly showed that the capacity of the vaccine strain to colonize specific body compartments conditions the pattern of vaccine-induced immune responses.

Infect Immun, 1999 Jul, 67(7), 3670 - 3
Human monocytic U937 cells kill Salmonella in vitro by NO-independent mechanisms; Ekman P et al.; Nitric oxide (NO) has a central role in host defense against intracellular microbes . HLA-B27 has been shown to directly modulate host-microbe interaction in vitro, leading to the impaired elimination of Salmonella in human monocytic U937 cells . Here, we studied whether impaired elimination of Salmonella would result from differences in NO production between HLA-B27- and HLA-A2-transfected U937 cells . Both human monocytic transfectants produced NO equally well and killed Salmonella via NO-independent mechanisms.

Infect Immun, 1999 Jul, 67(7), 3619 - 24
Salmonella typhi flagella are potent inducers of proinflammatory cytokine secretion by human monocytes; Wyant TL et al.; The cytokine production patterns of human peripheral blood mononuclear cells (PBMC) in response to Salmonella typhi flagella (STF) were examined in culture supernatants of PBMC stimulated with STF . Consistent with previous findings in volunteers vaccinated with aroC aroD deletion mutants of S . typhi, PBMC from volunteers immunized with the licensed live Ty21a S . typhi vaccine secreted gamma interferon following exposure to STF . Stimulation with STF induced rapid de novo synthesis of tumor necrosis factor alpha (TNF-alpha) and interleukin-1beta (IL-1beta), followed by IL-6 and IL-10 . Trypsin treatment of STF abrogated their effects, while polymyxin B had no effect . Intracellular cytokine measurements of STF-stimulated PBMC revealed the existence of monocyte subpopulations that produce only TNF-alpha, IL-1beta or both cytokines . Moreover, STF markedly decreased the percentage of CD14(+) cells . These data demonstrate that STF are powerful monocyte activators which may have important implications for vaccine development and for understanding the pathogenesis of S . typhi infection.

Infect Immun, 1999 Jul, 67(7), 3399 - 402
Induction of lethal shock and tolerance by Porphyromonas gingivalis lipopolysaccharide in D-galactosamine-sensitized C3H/HeJ mice; Tanamoto K; Lipopolysaccharide (LPS) obtained from Porphyromonas gingivalis was found to exhibit marked lethal toxicity in galactosamine-sensitized C3H/HeJ mice . Although no lethality was observed in mice intraperitoneally challenged with 1 mg of P . gingivalis LPS without galactosamine, when they were sensitized with 30 mg of galactosamine, challenge with 1 and 10 micrograms of LPS resulted in 67 and 100% lethality, respectively . The lethal dose of LPS was almost the same in LPS-responsive C57BL/6 mice and non-LPS-responsive C3H/HeJ mice . Furthermore, when 1 microgram of P . gingivalis LPS was administered to each mouse 90 min before the challenge with the same LPS with galactosamine, tolerance to the lethal action of LPS was induced, and the mice were completely protected from death, even at a dose 100-fold greater than the lethal dose of LPS . Neither a lethal effect nor induction of tolerance to the lethality of P . gingivalis LPS was exhibited by Salmonella LPS in galactosamine-sensitized C3H/HeJ mice . A protein-LPS complex derived from Pseudomonas aeruginosa, which exhibited strong lethality and induced tolerance to a subsequent challenge with a lethal dose of LPS in galactosamine-sensitized LPS-responsive mice, did not exhibit lethal toxicity in galactosamine-sensitized C3H/HeJ mice and failed to induce tolerance in these mice to the lethality of P . gingivalis LPS . These results indicate that P . gingivalis LPS plays the central role in the activation of non-LPS-responsive C3H/HeJ mice.

Am J Vet Res, 1999 Jun, 60(6), 708 - 13
Evaluation of 2-deoxy-D-glucose for induction of a stress response in pigs; Stabel TJ; OBJECTIVE: To determine the most effective route and dose for 2-deoxy-D-glucose (2DG) administration in swine, kinetics of 2DG, endogenous glucose concentration in the blood, effects of 2DG on cortisol concentration, and effects of 2DG administration in vivo on lymphocyte proliferation in vitro . ANIMALS: 14 Salmonella-free male and female mixed-breed pigs . PROCEDURE: A cannula was inserted in the femoral artery of each pig to allow for frequent blood collection with minimal external stress . The concentration and duration of 2DG in the blood was monitored while varying dose (250, 500, or 750 mg/kg of body weight) and route (IV, SC, IM, or IP) of 2DG administration . Blood samples were collected at various time points and assayed for lymphocyte response to concanavalin A and cortisol, endogenous glucose, and 2DG concentrations . RESULTS: The 2 best routes for administration of 2DG were IV and SC . If the IV route was chosen, the optimal dose was 500 mg of 2DG/kg; the optimal dose for SC administration was 750 mg/kg . CONCLUSIONS: 2DG induces a stress response in pigs similar to that in rodents . The use of 2DG in a porcine stress model should be effective for studying the possible role of stress in the pathogenesis and shedding of microorganisms.

Microbiology, 1999 May, 145 ( Pt 5), 1023 - 31
Fimbriae- and flagella-mediated association with and invasion of cultured epithelial cells by Salmonella enteritidis; Dibb-Fuller MP et al.; Salmonella enteritidis expresses flagella and several finely regulated fimbriae, including SEF14, SEF17 and SEF21 (type 1) . A panel of mutants was prepared in three strains of S . enteritidis to elucidate the role of these surface appendages in the association with and invasion of cultured epithelial cells . In all assays, the naturally occurring regulatory-defective strain 27655R associated with tissue culture cells significantly more than wild-type progenitor strains LA5 and S1400/94 . Compared with wild-type strains, SEF14 mutants had no effect on association and invasion, whereas SEF17, SEF21 and aflagellate mutants showed significant reductions in both processes . Histological examination suggested a role for SEF17 in localized, aggregative adherence, which could be specifically blocked by anti-SEF17 sera and purified SEF17 fimbriae . SEF21-mediated association was neutralized by mannose and a specific monoclonal antibody, although to observe enhanced association it was necessary for the bacteria to be in fimbriate phase prior to infection . Additionally, aflagellate mutants associated and invaded less than motile bacteria . This study demonstrated the potential for multifactorial association and invasion of epithelial cells which involved SEF17 and SEF21 fimbriae, and flagella-mediated motility.

Curr Opin Immunol, 1999 Jun, 11(3), 346 - 51
IL-12 and IFN-gamma in host defense against mycobacteria and salmonella in mice and men; Jouanguy E et al.; The development of gene-knockout mice and the identification of gene-deficient humans have improved our understanding of the role of IL-12 and IFN-gamma in host defense . Comparison of experimental and natural infections has shown that animals and humans genetically deficient in immunity mediated by IL-12 or IFN-gamma are highly susceptible to mycobacteria and salmonella . Impaired secretion of, or response to, IFN-gamma is the common pathogenic mechanism that accounts for impaired granuloma formation and uncontrolled growth of bacteria within macrophages . The axis formed between IL-12 and IFN-gamma is essential for protective immunity against mycobacteria and salmonella in mice and men.

Int J Food Microbiol, 1999 Apr 1, 48(1), 37 - 50
Resistance of Escherichia coli and Salmonella against nisin and curvacin A; Ganzle MG et al.; We have determined the effects of the following factors on the resistance of Gram-negative bacteria against nisin and curvacin A: (i) chemotype of the lipopolysaccharide (LPS), (ii) addition of agents permeabilizing the outer membrane, (iii) the fatty acid supply of the growth medium, and (iv) the adaptation to acid and salt stress . Bacteriocin activity was determined against growing and resting cells as well as protoplasts . All smooth strains of Escherichia coli and Salmonella enterica serovar Typhimurium were highly resistant towards the bacteriocins, whereas mutants that possess the core of the LPS, but not the O antigen, as well as deep rough LPS mutants were sensitive . Antibiotics with outer membrane permeabilizing activity, polymyxin B and polymyxin B nonapeptide, increased the sensitivity of smooth E . coli towards nisin, but not that of deep rough mutants . Incorporation of 1 g l(-1) of either oleic acid or linoleic acid to the growth media greatly increased the susceptibility of E . coli LTH1600 and LTH4346 towards bacteriocins . Both strains of E . coli were sensitive to nisin and curvacin A at a pH of less than 5.5 and more than 3% (w/v) NaCl . Adaptation to sublethal pH or higher NaCl concentrations (pH 4.54 and 5.35 or 4.5% (w/v) NaCl) provided only limited protection against the bacteriocidal activity of nisin and curvacin A . Adaptation to 4.5% (w/v) NaCl did not result in cross protection to bacteriocin activity at pH 4.4, but rendered the cells more sensitive towards bacteriocins.

Cancer Lett, 1999 Apr 1, 137(2), 137 - 43
Tumorigenicity and liver tumor ras-protooncogene mutations in CD-1 mice treated neonatally with 1- and 3-nitrobenzo{a}pyrene and their trans-7,8-dihydrodiol and aminobenzo{a}pyrene metabolites; Von Tungeln LS et al.; The environmental pollutants 1- and 3-nitrobenzo{a}pyrene (1- and 3-NBaP) are metabolized by mammalian microsomes through ring oxidation to 1-NBaP trans-7,8-dihydrodiol and 3-NBaP trans-7,8-dihydrodiol, and by nitroreduction to 1- and 3-aminobenzo{a}pyrene . To determine if these compounds are tumorigenic, 1- and 3-NBaP, along with several of their metabolites and the parent benzo{a}pyrene (BaP) and its trans-7,8-dihydrodiol metabolite, were tested in the neonatal CD-1 mouse bioassay . Male mice were administered i.p . injections at a total dose of 100 or 400 nmol per mouse on 1, 8 and 15 days after birth . While the liver tumor incidences for BaP, BaP trans-7,8-dihydrodiol, and the positive control 6-nitrochrysene (6-NC) were significantly higher than in the solvent control animals, all the other tested compounds exhibited no tumorigenicity . The frequency of Ha- and Ki-ras mutations in liver tumors of mice treated with BaP, BaP trans-7,8-dihydrodiol, and 6-NC were higher than in the few liver tumors isolated from control mice or mice treated with the NBaPs or their metabolites . Since 1- and 3-NBaP and their metabolites are potent mutagens in the Salmonella assay and moderate mutagens in the Chinese hamster ovary (CHO) mammalian mutagenicity assay, our results indicate that the in vitro mutagenicity of these compounds does not correlate with their tumorigenicity.

Rev Environ Health, 1999 Jan-Mar, 14(1), 31 - 7
The use of epidemiological data in the control of foodborne viruses; Powell SC et al.; The Codex Committee on Food Hygiene has recommended the adoption of Hazard Analysis and Critical Control Point (HACCP) as the basis for food safety control . To provide an objective basis for the construction of HACCP systems, epidemiological data are required . The data should be accurate, up-to-date, and identify emerging pathogens, such as viruses . The number of laboratory reports of small, round-structured viruses in England and Wales has increased from 400 cases in 1990 to 2387 in 1996 . Although a food vehicle is not essential for the spread of viral particles, food my be the primary unidentified vehicle . The Advisory Committee on the Microbiological Safety of Foods recommends the use of the Kaplan Criteria, which can give strong circumstantial evidence that an outbreak is attributable to small, round-structured viruses . The application of these criteria would give a more accurate reflection of the involvement of viruses in the incidence of foodborne disease . This review considers the use of epidemiological data to support HACCP and risk-assessment systems . It discusses the implications of focusing on traditional pathogens, for example Salmonella spp., as opposed to emerging pathogens, for the design of control systems . Recommendations are made for improving the system of data collection.

Microb Pathog, 1999 Jul, 27(1), 55 - 9
Immunization of mice with live oral vaccine based on a Salmonella enterica (sv Typhimurium) aroA strain expressing the Escherichia coli O111 O antigen; Wang L et al.; Shiga toxin-producing Escherichia coli strains of serogroup O111 are the most frequently isolated non-O157 strains causing outbreaks of gastroenteritis with haemolytic uraemic syndrome (HUS) . O antigen is a major antigen in Gram-negative bacteria, and it has been shown that O111 is a protective antigen . Attenuated Salmonella enterica sv Typhimurium aroA strain STM-1 was used as a live carrier to express the E . coli O111 O antigen . Mice immunized intraperitoneally produced serum immunoglobulin G, and mice immunized orally produced serum immunoglobulin G and secretory immunoglobulin A in the intestine against E . coli O111 cells as determined by enzyme-linked immunosorbent assays .

Pediatr Radiol, 1999 Jun, 29(6), 469 - 71
Ultrasonographic assessment of Salmonella enterocolitis in children; Ueda D et al.; BACKGROUND: Salmonella enterocolitis (SE) is one of the important causes of acute infectious diarrhoea . Imaging studies are rarely performed on these patients . Consequently, ultrasound (US) features of SE are controversial . OBJECTIVE: To identify the clinical significance of US in the evaluation of SE . MATERIAL AND METHODS: Abdominal US was performed in 15 patients with SE and 9 patients with Rotavirus enterocolitis (RE) . RESULTS: Ascites was present in 60 % and mural thickening of the colon in 40 % of patients with SE on abdominal US, whereas we could not identify these features in patients with RE . In patients with SE, colonic wall thickening; and ascites, the levels of C-reactive protein (CRP) were significantly higher as compared to patients with SE and no colonic wall thickening or ascites . Also, the stool occult blood test was positive more often in patients with colonic wall thickening and ascites on US than in patients without these findings . The colonic wall thickness significantly correlated with CRP and stool occult blood level . CONCLUSIONS: US is able to identify pathological changes in bowel and intra-abdominal spaces . The US findings of ascites and colonic wall thickening may be useful for determining the severity of SE.

Genetika, 1999 Mar, 35(2), 303 - 8
{Natural plasmid pSD89 (Cmr) from Salmonella derby K89, which increases the radiation tolerance of Escherichia coli strain K-12}; Verbenko VN et al.; Several plasmids with molecular mass of 1.3-9 MDa were found in a clinical isolate of Salmonella derby K89 by electrophoresis in agarose gel . One of these plasmids, designated pSD89 (Cmr), was derived from the K89 strain via transformation of the plasmidless recipient S . derby K82 to chloramphenicol resistance . The plasmid-carrying strain K89 and the K82 strain completely cured of plasmids were equally sensitive to the lethal action of UV light, whereas the plasmid-carrying strain was even more sensitive to ionizing radiation than the plasmidless variant . Nevertheless, transformants carrying only plasmid pSD89 (Cmr) were found to be more resistant to gamma-rays and UV light than the recipient . By using an intermediate host Escherichia coli Z80 (r-m+), plasmid pSD89 (Cmr) was introduced into different E . coli K-12 strains: polA-, recA-, uvrA-, umuC-, and the wild-type strain . A slight increase in radioresistance of E . coli wild-type cells and a significant complementation of a repair defect in recA and polA mutants, but not in uvrA and umuC, were observed.

Vaccine, 1999 Apr 23, 17(17), 2150 - 61
High efficiency gene replacement in Salmonella enteritidis: chimeric fimbrins containing a T-cell epitope from Leishmania major; White AP et al.; A simple, high frequency chromosomal gene replacement method of general utility was developed for Salmonella enteritidis . This system uses an unstable, imperfectly segregating, temperature-sensitive replicon, pHSG415, as a carrier of the recombinant gene of interest . It also allows for site-specific replacement of chromosomal genes without the need for antibiotic resistance markers in the recombinant genes or the use of specific bacterial strains . This strategy was used to replace the chromosomal sefA and agfA fimbrin genes of S . enteritidis 3b with recombinant genes containing a 48 bp DNA fragment encoding PT3, an immunoprotective T-cell epitope from GP63 of Leishmania major . The fidelity of chimeric fimbrial replacements were confirmed by DNA sequence analysis . Nearly 30% of the S . enteritidis clones selected in the final stage of sefA mutagenesis contained the sefA::PT3 recombinant gene, whereas for agfA the efficiency was as high as 10% . To our knowledge, this is the first report of fimbrial epitope replacement in the Salmonellae and the first chimeric fimbrin genes that have been reconstituted into a wild-type genetic background for any organism . As such, this model represents a promising 'organelle' expression system for epitope display in vaccinology.

Zhonghua Yi Xue Za Zhi (Taipei), 1999 Apr, 62(4), 239 - 43
Primary Salmonella iliopsoas abscess: a case report; Yu WL; Primary iliopsoas abscesses are usually hematogenous or seeded via the lymphatic system from an occult focus . Staphylococcus aureus has been reported to be the predominant pathogen, whereas Salmonella sp has rarely been reported to be a major pathogen . We report the case of a 63-year-old woman who presented with a prolonged fever of two weeks' duration . On admission, physical examination revealed tenderness over the left lower abdomen and hip joint, with her thigh in constant flexion . Computerized tomography of the abdomen revealed an iliac fossa abscess . The drained pus culture yielded Salmonella group B . Percutaneous catheter drainage and appropriate antimicrobial therapy with ciprofloxacin eventually yielded good results . There was no evidence of other underlying diseases predisposing the patient to the formation of iliopsoas abscess . Salmonella infection should be considered in the diagnostic protocols of iliopsoas abscess in Taiwan, where salmonellosis is prevalent.

J AOAC Int, 1999 May-Jun, 82(3), 634 - 47
Salmonella in foods--a new enrichment procedure for use with the TECRA Salmonella visual immunoassay: collaborative study; Hughes D et al.; A collaborative study was conducted to compare a new enrichment procedure for the TECRA Salmonella Visual Immunoassay with the reference method given in the U.S . Food and Drug Administration's Bacteriological Analytical Manual (BAM 7th Ed.) . Three food types (milk powder, black pepper, and soy flour) were analyzed in Australia, and 3 food types (milk chocolate, dried egg, and raw turkey) were analyzed in the United States . Thirty-eight collaborators participated in the study . No significant differences (p > 0.05) were observed for the pairwise comparison of the proportion of positive samples for the TECRA method with that for the reference method . The new enrichment procedure for the TECRA method has been adopted First Action by AOAC INTERNATIONAL.

J AOAC Int, 1999 May-Jun, 82(3), 625 - 33
Reveal for Salmonella test system; Bird CB et al.; The Reveal for Salmonella (RSS) test system is a presumptive qualitative test that detects the presence of Salmonella organisms in foods within 21 h total testing time, allowing the user to release negative products 24 h earlier than when using other rapid test kits . Foods are enriched with a proprietary resuscitation medium called Revive and then selectively enriched with either Selenite Cystine or Rappaport-Vassiliadis selective media . The enriched culture is used to inoculate the RSS detection device, which initiates a lateral flow through a reagent zone containing anti-Salmonella antibodies conjugated to colloidal gold particles that capture antigens present in the culture . The antigen-antibody complex migrates farther and is captured by an additional anti-Salmonella antibody, causing the colloidal gold to precipitate and form a visual line, indicating a positive result . A procedural control line also will form regardless of the presence of Salmonella organisms to indicate the test is working properly . Existing AOAC Official Methods for Salmonella organisms require a 48 h enrichment before testing . Hence, a food product has to be held before release, adding extra cost to the company and the consumer . The RSS test system was evaluated by quantitative spiking studies . Although AOAC encourages inclusion of naturally contaminated foods, almost all microbiological AOAC validation studies have been performed with artificially contaminated foods for absolute control over the study . The RSS test system is designed to test many food types for Salmonella organisms and has a limit of detection of 5-10 colony-forming units (cfu)/25 g with a false-negative rate of < 1% and a false-positive rate of < 5.0% . It showed an 81% overall agreement with the traditional procedure of the U.S . Department of Agriculture's Food Safety Inspection Service.

Mol Biotechnol, 1999 Feb, 11(1), 101 - 4
A cloning vector for efficient generation of cholera toxin B gene fusions for epitope screening; Secundino I et al.; Gene fusion proteins with epitopes attached to the amino end of cholera toxin B subunit (CTB) are useful to raise immunological responses . We describe a cloning vector, designated pCTBtet, carrying a tetracycline resistance gene (TetR) between the leader peptide and mature CTB . Removal of TetR to insert oligonucleotides encoding fusion epitopes allowed for screening of tetracycline-sensitive clones . Restoration of the correct CTB reading phase was subsequently used to choose gene fusion candidate colonies . The use of pCTBtet permitted the rapid construction of 8 fusion proteins carrying 9-24 aa from Salmonella typhi OmpC and 6 hybrids with 7-31 aa from Escherichia coli colonization factor CFAI.

Plasmid, 1999 May, 41(3), 207 - 18
Sequencing and characterization of Salmonella typhi plasmid R27 (incompatibility group HI1) trhC, a transfer gene encoding a potential nucleoside triphosphate-binding domain; Taylor DE et al.; IncHI1 plasmids are one of the few plasmids known to mediate multiple antibiotic resistance in Salmonella typhi . These plasmids are temperature-sensitive for transfer and R27 is the prototype plasmid . DNA sequencing within the Tra2 region of R27, encoding genes involved in mating pair formation, identified trhC encoding the TrhC protein of 90,000 Da, which was visualized using an in vitro transcription/translation system . Expression of the TrhC protein also identified two smaller protein products of approximately 23 and 25 kDa which are predicted to be protease digestion products . The migration of these smaller products changed when the reactions were run at 28 vs 37 degrees C . The TrhC protein contained a putative nucleotide triphosphate-binding protein and exhibited sequence similarities with several other proteins implicated in bacterial conjugation, including TraC (F), TraB (pKM101), VirB4 (Ti), TrbE (RP4) . Phylogenetic analysis showed TrhC was most closely related to TraC . Mini-Tn10 insertions in trhC generated transfer defective mutants, and no pili were specified by the trhC mutants . The trhC gene appeared to be a hot spot for transposon insertion as 37.5% mapped into this open reading frame . One trhC mutant, pDT2990, was able to be complemented by a cloned trhC gene giving a transfer frequency of 1 x 10(-3) transconjugants per recipient in an 18-h mating, whereas the wild-type transfer frequency of R27 was 1 x 10(-2) transconjugants per recipient .

Enferm Infecc Microbiol Clin, 1999 Apr, 17(4), 166 - 70
{Salmonella and salmonellosis in the Asturias District, Spain, during a seven year period (1990-1996)}; Gonzalez-Hevia MA et al.; BACKGROUND: Retrospective study of the Salmonella sp . strains and human salmonellosis episodes registered in the Public Health Laboratory of the Principado de Asturias, Spain, over the seven year period 1990-1996 . MATERIAL AND METHODS: All strains were serotyped; strains of serotypes Typhi and Typhimurium were also phage typed . The strains were grouped according to: sample of origin, age group; season of the year; time distribution, and epidemiological presentation (sporadic episode or outbreak) . RESULTS AND DISCUSSION: A total of 3,255 Salmonella isolates were registered and conserved in the period under study . They were adscribed to 45 serotypes, being Enteritidis, Typhimurium, Virchow and Hadar (57.1, 26.6, 4.5 and 2%, respectively) the most frequent . 3,193 isolates were collected from clinical samples (corresponding to 3,067 patients), 32 from environmental water or sewage, 28 from food and 2 from animal stools . Relevant epidemiological findings were: the most affected age group was children under 4 years old (32.3%), the season with highest incidence was the summer . The most frequent clinical presentation was the sporadic episode of gastroenteritis (97%) . Seventy five outbreaks (22 communitary and 53 family) were registered, being associated with six serotypes: Enteritidis (76%), Typhimurium, Virchow, Hadar, Infantis and Coehl.

Int J Exp Pathol, 1999 Feb, 80(1), 11 - 6
Protective effect of pentoxifylline plus thalidomide against septic shock in mice; Arrieta O et al.; Mortality caused by septic shock in experimental animals is reduced by thalidomide, an inhibitor of tumour necrosis factor alpha . Another drug that could act on the pathophysiological mechanisms of septic shock is pentoxifylline, an inhibitor of platelet aggregation that increases the flexibility of the erythrocyte membrane and has fibrinolytic activity . We studied the effect of pentoxifylline alone and combined with thalidomide in septic shock; 97 NIH mice were injected with lipopolysaccharides of Salmonella abortus equi and D galactosamine . Animals were separated in 4 groups; group A (n = 20) was used as control, group B (n = 15) received thalidomide 50 mg/kg, group C (n = 20) received pentoxifylline 40 mg/kg, and group D (n = 15) received thalidomide plus pentoxifylline . Mortality was recorded every hour . Additionally, 5 animals from each group were sacrificed 8 h after the induction of septic shock for histological analysis of heart, lung, brain, kidney, small intestine, adrenal glands and liver . Microscopic findings were rated as absent, mild, moderate and severe damage . In control animals histological analysis showed intense haemorrhage and necrosis in all organs studied . When compared with controls, treatment with pentoxifylline plus thalidomide reduced mortality (P < 0.03) . The tissue damage was less severe in animals from the groups that received pentoxifylline or pentoxifylline plus thalidomide (P < 0.05) . Pentoxifylline seems to potentiate the beneficial effects of thalidomide, reducing mortality and attenuating the pathological changes produced by septic shock.

J Clin Microbiol, 1999 Jul, 37(7), 2381 - 2
Typhoid fever due to Salmonella Kapemba infection in an otherwise healthy middle-aged man; Sarnighausen HE et al.; We report the case of a patient with a Salmonella Kapemba infection, who suffered, 3 weeks after a holiday in Israel, occurrences of high fever and lower back pain for 10 days and icterus for 2 days before admission . Laboratory findings revealed a slight cholestasis and elevation of acute phase protein levels . In the blood culture a Salmonella Kapemba-type organism was cultured . The patient was afebrile for 10 days after hospitalization and then suddenly developed a temperature of 40 degrees C again . At the same time leukopenia, thrombocytopenia, and a rise of D-dimer levels were detected . The patient was admitted to the intensive care unit for a few days, because a disseminated intravascular coagulation was suspected . With magnetic resonance imaging and bone scintigraphy no osteomyelitis or abscess formation could be found . A transesophageal ultrasonography of the heart revealed no signs of endocarditis . In multiple stool cultures no salmonellas could be detected . After antibiotic treatment with ciprofloxacin the fever and lower back pain subsided, and the patient was discharged a fortnight later . This is the first reported case of typhoid fever due to the bacterium Salmonella Kapemba.

J Clin Microbiol, 1999 Jul, 37(7), 2312 - 6
Evaluation of Statens Serum Institut enteric medium for detection of enteric pathogens; Blom M et al.; The efficacy of the Statens Serum Institut (SSI) enteric medium for isolation and direct identification of enteric pathogens was evaluated . Six different biochemical reactions can be read by using the SSI enteric medium, allowing direct identification of a range of enteric pathogens . All 248 gram-negative bacterial species that were tested grew on the SSI enteric medium . Only 10 of 248 bacteria (4%) showed discrepant results in the biochemical reactions, and none of these were enteric pathogens . Forty-three of 47 enteric pathogens (92%) produced identical rates of semiquantitative growth on the SSI enteric medium and 5% blood agar, whereas three Vibrio spp . and one Aeromonas spp . showed reduced growth . Gram-positive bacteria did not grow on the SSI enteric medium . Most enteric pathogens had a detection limit of 50 bacteria per ml of feces, but higher numbers of Vibrio spp . and some Shigella spp . were required for detection . The growth rates of 125 enteric pathogens and 12 Yersinia spp . on the SSI enteric medium, xylose lysine deoxycholate (XLD), Hektoen enteric (HE), Salmonella-Shigella (SS), and cefsulodin-irgasan-novobiocin (CIN) agar were compared . Detection rates after application of 200 CFU were 99% for SSI enteric medium, 92% for XLD, 88% for HE, and 82% for SS agar . The 12 Yersinia spp . grew excellently on both the SSI enteric medium and CIN agar . We conclude that the performance of the SSI enteric medium compares favorably to those of other media tested . Its ability to detect Yersinia spp . may limit the number of media needed in the typical laboratory . The direct identification of enteric pathogens on the medium may also provide a more rapid diagnosis.

J Clin Microbiol, 1999 Jul, 37(7), 2176 - 82
Salmonella enteritidis phage types 1 and 4: pheno- and genotypic epidemiology of recent outbreaks in Finland; Lukinmaa S et al.; In the 1990s, Salmonella enterica subsp . enterica serovar Enteritidis has caused 15 outbreaks in Finland; 12 of them were caused by phage type 1 (PT1) and PT4 . Thus far, there has been no clear evidence as to the source of these Salmonella Enteritidis PT1 and PT4 strains, so it was necessary to try to characterize them further . Salmonella Enteritidis PT1 (n = 57) and PT4 (n = 43) isolates from different sources were analyzed by genomic pulsed-field gel electrophoresis (PFGE), plasmid profiling, and antimicrobial resistance testing to investigate the distribution of their subtypes in Finland . It was also hoped that this investigation would help in identifying the sources of the infections, especially the sources of the outbreaks caused by PT1 and PT4 in the 1990s . The results showed that both PFGE and plasmid profiling, but not antimicrobial susceptibility testing, were capable of differentiating isolates of Salmonella Enteritidis PT1 and PT4 . By genotypic methods, it was possible to divide both PT1 and PT4 isolates into 12 subtypes . It could also be shown that all PT1 outbreak isolates were identical and, at least with this collection of isolates, that the outbreaks did not originate from the Baltic countries or from Russia, where this phage type predominates . It was also established that the outbreaks caused by PT4 all had different origins . Valuable information for future investigations was gained on the distribution of molecular subtypes of strains that originated from the tourist resorts that are popular among Finns and of strains that were isolated from livestock.

FEMS Microbiol Lett, 1999 Jun 1, 175(1), 101 - 6
Molecular cloning of an immunogenic and acid-induced isocitrate dehydrogenase gene from Coxiella burnetii; Van Nguyen S et al.; The Coxiella burnetii icd gene encoding an immunogenic dimeric NADP(+)-dependent isocitrate dehydrogenase (IDH) was cloned by screening a C . burnetii genomic library with a human positive serum and sequenced . The predicted gene product consists of 427 amino acids (M(r) = 46,600) and showed high identity to the IDHs of Escherichia coli (74%), Salmonella enterica (73%) and IDH-I of Vibrio sp . (71%) . The cloned gene complemented an icd-defective E . coli mutant producing a recombinant IDH that had the same biochemical properties as the enzyme from purified C . burnetii . Unlike the homologs from other bacteria, the cloned enzyme was expressed to the highest level in low pH conditions . This distinct property of the cloned IDH suggests that C . burnetii icd gene may have a role in the adaptation of the organism to the harsh acidic environment of the eucaryotic phagolysosomes.

Anal Chem, 1999 May 15, 71(10), 1963 - 6
Colloidal gold filtrates as metal substrates for surface-enhanced infrared absorption spectroscopy; Seelenbinder JA et al.; A new method for obtaining surface-enhanced infrared absorption (SEIRA) spectra of antibodies and antibody/antigen complexes has been developed . Antibodies attached to colloidal gold particles and then collected by filtration onto porous polyethylene membranes show enhanced spectral bands at 1080 and 990 cm-1 regardless of the antibody specificity . Attachment of a model antigen, glucose oxidase, to its specific antibody/colloid complex prior to collection produces enhanced bands at 1540, 1395, and 1250 cm-1 . Similarly, when the antigen Salmonella is attached to its specific antibody/colloid complex prior to collection, a new enhanced band is observed at 1015 cm-1 . Similarities and differences of the SEIRA spectra obtained on gold colloid are compared to previous work on gold films.

Nature, 1999 May 27, 399(6734), 375 - 9
A bacteriophage encoding a pathogenicity island, a type-IV pilus and a phage receptor in cholera bacteria; Karaolis DK et al.; The virulence properties of many pathogenic bacteria are due to proteins encoded by large gene clusters called pathogenicity islands, which are found in a variety of human pathogens including Escherichia coli, Salmonella, Shigella, Yersinia, Helicobacter pylori, Vibrio cholerae, and animal and plant pathogens such as Dichelobacter nodosus and Pseudomonas syringae . Although the presence of pathogenicity islands is a prerequisite for many bacterial diseases, little is known about their origins or mechanism of transfer into the bacterium . The bacterial agent of epidemic cholera, Vibrio cholerae, contains a bacteriophage known as cholera-toxin phage (CTXphi), which encodes the cholera toxin, and a large pathogenicity island called the VPI (for V . cholerae pathogenicity island) which itself encodes a toxin-coregulated pilus that functions as a colonization factor and as a CTXphi receptor . We have now identified the VPI pathogenicity island as the genome of another filamentous bacteriophage, VPIphi . We show that VPIphi is transferred between V . cholerae strains and provide evidence that the TcpA subunit of the toxin-coregulated type IV pilus is in fact a coat protein of VPIphi . Our results are the first description of a phage that encodes a receptor for another phage and of a virus-virus interaction that is necessary for bacterial pathogenicity.

Vet Res Commun, 1999 Mar, 23(2), 81 - 90
Adjuvanted outer membrane protein vaccine protects poultry against infection with Salmonella enteritidis; Meenakshi M et al.; The immunogenicity of a sonicated extract (SE) and of outer membrane proteins (OMP) of Salmonella enteritidis was tested in birds of about 8 weeks of age . The dose, route of vaccination and the adjuvant used varied in different groups of birds . Two vaccine doses with or without adjuvant were given parenterally or orally 3 weeks apart . OMP vaccines gave significantly higher antibody titres than SE vaccines, as indicated by ELISA . The vaccines adjuvanted with oil produced higher antibody titres than those without any adjuvant . A dose of 1 mg of vaccine produced higher antibody titres than 0.5 mg of vaccine . Adjuvanted vaccine given subcutaneously elicited higher antibody responses than oral vaccines given without adjuvant . The birds were challenged with virulent S . enteritidis organisms at the end of the second week after a booster dose . None of the birds given 1 mg of OMP vaccine subcutaneously shed the organisms when tested by culturing cloacal swabs, although a few birds vaccinated with 0.5 mg of OMP vaccine did so . In general, adjuvanted OMP vaccines gave better protection than SE vaccines.

Vnitr Lek, 1998 Sep, 44(9), 551 - 4
{Whipple's disease, early diagnosis, early therapy}; Vykouril J et al.; The authors describe a case of Whipple's disease diagnosed early during gastroduodenofibroscopy from a bioptioc specimen of the prepyloric gastric mucosa, and treated in time . The disease was complicated by superinfection with Salmonella enteritidis . In the clinical picture digestive symptoms predominated, loose stools, malabsorption, loss of body weight, anaemia, skin pigmentation . After antibiotic and later chemotherapeutic treatment clinical symptoms receded and the histological finding in bioptic specimens from the stomach was normal.

Minerva Cardioangiol, 1999 Jan-Feb, 47(1-2), 31 - 7
Salmonella mycotic aneurysms: traditional and "alternative" surgical repair with arterial homograft; Locati P et al.; Salmonella infection of the abdominal aorta with formation of mycotic aneurysm is rare, but associated with a high mortality and morbidity . Prompt surgical treatment and selective and prolonged antibiotic therapy are required because of its rapid and impredictable evolution in a short period of time, even if an infectivous etiology is only suspected . Methods of revascularization can be different: the traditional two are in situ or extraanatomic bypass using synthetic graft . Both these solutions are subject to complications . An "alternative" method of revascularization with low risk of infection and good patency is the use of arterial homograft in situ . We report two cases of Salmonella mycotic aortic aneurysms successfully treated with revascularization respectively by extraanatomic bypass using synthetic graft and in situ arterial homograft . The reasons for our choice are also discussed.

Zh Mikrobiol Epidemiol Immunobiol, 1999 Mar-Apr, (2), 11 - 5
{The effect of an artificial magnetic field on Salmonella infection in mice}; Kalutskii PV et al.; Experimental Salmonella infection in mice, developing simultaneously with the prolonged action of an artificial constant magnetic field with induction equal to 3 x 10(-4) T, was found to induce a pronounced decrease in nonspecific resistance in the animals . The study of Salmonella population structure revealed that the cells selected the animals subjected to the action of the artificial magnetic field had mostly a lesser number of signs of antibiotic resistance . By the end of the experiment Salmonella cultures isolated from the mice subjected to the action of the artificial magnetic field were characterized by greater virulence and resistance to the bactericidal action of blood serum . The use of sodium nucleinate under the conditions of the action of the artificial magnetic field enhanced the level of anti-infectious protection in the animals, which changed the direction of cell selection in Salmonella population towards cells with a greater number of markers of antibiotic resistance.

Epidemiol Infect, 1999 Apr, 122(2), 209 - 15
A Mexican restaurant-associated outbreak of Salmonella Enteritidis type 34 infections traced to a contaminated egg farm; McNeil MM et al.; In May 1996, the Georgia Division of Public Health was notified about a cluster of persons with Salmonella Enteritidis (SE) infections in Waycross, Georgia . A matched pair case-control study to determine risk factors for illness found a statistically significant association of SE infection with a history of having eaten at Restaurant A during the 5 days before onset of illness (relative risk = 13 {95% confidence interval (CI) = 3-62, P < 0.01}) . In a second case-control study, to determine specific food exposures, consumption of a deep-fried Mexican dish (chile relleno) (4 of 21 cases vs . 0 of 26 controls, odds ratio undefined, 95% CI > 1.46, P = 0.034) was found to be significantly associated with SE infection . An environmental investigation found evidence of suboptimal food storage and cooking temperatures at Restaurant A; cross contamination of foods may have contributed to the low attributable risk identified for chile rellenos . Five of 37 Restaurant A food and environment specimens yielded SE strains . All five positive specimens were from chiles rellenos . Of the seven outbreak-associated strains (six patient isolates and one food isolate from Restaurant A) for which phage typing was conducted, all were phage type 34 . A FDA traceback investigation through Restaurant A's single-egg supplier identified the potential source as three interrelated farms in South Carolina . Environmental culture from one of these farms yielded SE phage type 34 . As a result of this outbreak, FDA helped institute a statewide egg quality-assurance programme in South Carolina to minimize SE contamination of eggs.

Epidemiol Infect, 1999 Apr, 122(2), 201 - 7
Salmonellosis in North Thames (East), UK: associated risk factors; Banatvala N et al.; We assessed the rate of salmonella infections and risk factors associated with infection in North East Thames in 1993 . Cases of culture confirmed infection were identified through microbiology laboratories and environmental health officers in the North East Thames . A total of 1730 cases were reported and 209 of these individuals (those who could be contacted within a 3-week interval after onset of symptoms) and matched controls were interviewed by telephone . In addition randomly selected controls were interviewed over a 4-month period about recent gastric acid lowering medication and antimicrobial ingestion . Sixty-six serotypes were identified: S . enteritidis was isolated from 1179 (69%) cases, S . typhimurium from 221 (13%), S . virchow from 77 (4%) and S . newport 25 (1%) . Infections were more frequent in summer months . Highest rates were documented in children under 2 years of age for S . enteritidis (108/100,000) and under 1 year for S . typhimurium (36/100,000) . Using the Townsend score, highest isolation rates of S . enteritidis were in more prosperous areas (36/100,000 vs . 27/100,000; odds ratio (OR) 1.3, 95% confidence intervals (CIs) 1.2-1.6, P < 0.0001), while for S . typhimurium, there was no relation between deprivation index and isolation rates areas (6.4/100,000 vs . 6.1/100,000; OR 1.1, 95% CIs 0.8-1.5, P = 0.77) . The case control study showed a significant association between ingestion of products containing raw eggs and S . enteritidis infection (8/111 cases vs . 0/110 controls; OR undefined, lower 95% CIs 3.4) . Individuals with salmonella infection were significantly more likely to have travelled abroad in the week before the onset of illness {42/186 (23%) vs . 1/182 (0.5%); OR 40, 95% CIs = 5.5-291, P < 0.001} and to report gastroduodenal disease {11/143 (7%) vs . 3/143 (2%); OR 5.0, 95% CIs = 1.1-23, P = 0.04} . There was an association between illness and gastric acid-lowering medications {unmatched controls OR 22.3 (95% CIs 1.5-3.7, P = 0.0002), matched controls OR 3.7 (95% CIs 1.0-3.8, P = 0.07)}, but no association with antimicrobial ingestion.

Shock, 1999 May, 11(5), 330 - 5
Tolerance to LPS decreases macrophage G protein content; Fernando LP et al.; The effects of tolerizing doses of LPS on mRNA and protein levels of three different G protein subunits were investigated to understand the mechanism(s) responsible for the reduction in Gialpha protein content in LPS tolerance . Tolerance was induced in rats using Salmonella enteritidis LPS (intraperitoneal route) with a single dose of 100 microg/kg . Peritoneal macrophages were harvested 6 and 24 h later . In some studies, a second dose of LPS 500 microg/kg was given on the following day, and peritoneal macrophages were harvested 5 days after the first injection . Macrophage RNA or a crude membrane fraction was prepared from macrophages, and the mRNA level or the protein content for Gialpha3, Gialpha2, and Gsalpha was analyzed using Northern or Western blots, respectively . Compared with the control levels, the message for Gialpha3 was reduced (p < .025) at 6 and 24 h and 5 day time periods after LPS treatment . The Gialpha2 mRNA was increased relative to the control levels (p < .05) at 6 h and 5 days after LPS treatment, respectively, and Gsalpha message was not significantly changed . The half-life of Gialpha3 mRNA was not significantly different in control versus tolerant macrophages . The Gialpha3 mRNA and membrane protein were not significantly changed by incubation with LPS for intervals up to 6 h in vitro . Macrophage membrane Gialpha3 and Gialpha1 and 2 protein content from tolerant rats were reduced compared with the controls at 6 and 24 h, respectively (p < .05) . These studies are consistent with our previous observations of selective changes in macrophage Gialpha protein content in LPS tolerance and raise the possibility that this may affect signal transduction events in these cells.

J Bacteriol, 1999 Jun, 181(11), 3536 - 41
Role of genomic rearrangements in producing new ribotypes of Salmonella typhi; Ng I et al.; Salmonella typhi is the only species of Salmonella which grows exclusively in humans, in whom it causes enteric typhoid fever . Strains of S . typhi show very little variation in electrophoretic types, restriction fragment length polymorphisms, cell envelope proteins, and intervening sequences, but the same strains are very heterogeneous for ribotypes which are detected with the restriction endonuclease PstI . In addition, the genome of S . typhi has been proven to undergo genomic rearrangement due to homologous recombination between the seven copies of rrn genes . The relationship between ribotype heterogeneity and genomic rearrangement was investigated . Strains of S . typhi which belong to 23 different genome types were analyzed by ribotyping . A limited number of ribotypes were found within the same genome type group; e . g., most strains of genome type 3 belonged to only two different ribotypes, which result from recombination between rrnH and rrnG operons . Different genome type groups normally have different ribotypes . The size and identity of the PstI fragment containing each of the seven different rrn operons from S . typhi Ty2 were determined, and from these data, one can infer how genomic rearrangement forms new ribotypes . It is postulated that genomic rearrangement, rather than mutation, is largely responsible for producing the ribotype heterogeneity in S . typhi.

J Bacteriol, 1999 Jun, 181(11), 3433 - 7
Growth phase-regulated induction of Salmonella-induced macrophage apoptosis correlates with transient expression of SPI-1 genes; Lundberg U et al.; Invasive Salmonella has been reported to induce apoptosis in a fraction of infected macrophages within 2 to 14 h from the time of infection by a mechanism involving the type III secretion machinery encoded by the Salmonella pathogenicity island 1 (SPI-1) . Here, we show that bacteria in the transition from logarithmic to stationary phase cause 90% of the macrophages to undergo phagocytosis-independent, caspase-mediated apoptosis within 30 to 60 min of infection . The ability of Salmonella to induce this rapid apoptosis was growth phase regulated and cell type restricted, with epithelial cells being resistant . Apoptosis induction was also abrogated by disruption of the hilA gene (encoding a regulator of SPI-1 genes) and by the expression of a constitutively active PhoPQ . hilA itself and a subset of SPI-1 genes were transiently expressed during aerobic growth in liquid medium . Interestingly, however, hilA was found to be required only for the expression of the prgH gene, while sipB, invA, and invF were expressed in a hilA-independent manner . The expression of SPI-1 genes and the secretion of invasion-associated proteins correlated temporally with the induction of apoptosis and are likely to represent its molecular basis . Thus, growth phase transition regulates the expression and secretion of virulence determinants and represents the most efficient environmental cue for apoptosis induction reported to date.

Antimicrob Agents Chemother, 1999 Jun, 43(6), 1441 - 4
Azithromycin versus ciprofloxacin for treatment of uncomplicated typhoid fever in a randomized trial in Egypt that included patients with multidrug resistance; Girgis NI et al.; To compare clinical and bacteriological efficacies of azithromycin and ciprofloxacin for typhoid fever, 123 adults with fever and signs of uncomplicated typhoid fever were entered into a randomized trial . Cultures of blood were positive for Salmonella typhi in 59 patients and for S . paratyphi A in 3 cases; stool cultures were positive for S . typhi in 11 cases and for S . paratyphi A in 1 case . Multiple-drug resistance (MDR; resistance to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole) was present in isolates of 21 of 64 patients with positive cultures . Of these 64 patients, 36 received 1 g of azithromycin orally once on the first day, followed by 500 mg given orally once daily on the next 6 days; 28 patients received 500 mg of ciprofloxacin orally twice daily for 7 days . Blood cultures were repeated on days 4 and 10 after the start of therapy, and stool cultures were done on days 4, 10, and 28 after the start of therapy . All patients in both groups improved during therapy and were cured . Defervescence (maximum daily temperatures of </=38 degrees C) occurred at the following times {mean +/- standard deviation (range)} after the start of therapy: 3.8 +/- 1.1 (2 to 7) days with azithromycin and 3.3 +/- 1.0 (1 to 5) days with ciprofloxacin . No relapses were detected . Cultures of blood and stool during and after therapy were negative in all cases, except for one patient treated with azithromycin who had a positive blood culture on day 4 . These results indicated that azithromycin and ciprofloxacin were similarly effective, both clinically and bacteriologically, against typhoid fever caused by both sensitive organisms and MDR S . typhi.

J Appl Microbiol, 1999 May, 86(5), 761 - 8
Use of pulsed field gel electrophoresis as an epidemiological tool for analysis of sporadic associated strains of Salmonella typhi isolated in Taiwan; Tsen HY et al.; In order to characterize the subtypes of Salmonella typhi which cause sporadic disease in Taiwan, 55 isolates of Salm . typhi obtained from unrelated patients of sporadic cases during 1992-96 were subjected to chromosomal DNA digestion and pulsed field gel electrophoresis (PFGE) . When DNAs of these 55 Salm . typhi strains were digested with XbaI, 41 PFGE patterns were observed . Strains sharing the same XbaI digestion pattern could not be further discriminated by PFGE analysis using SpeI and NotI as digestion enzymes . Thus, considerable genetic diversity exists among the Salm . typhi isolates . Although strains of the same patterns were mainly isolated during the same time, recirculation of certain infectious strains could be possible . When 12 antibiotics, i.e . ampicillin, trimethoprim/sulfamethoxazole, erythromycin, norfloxacin, tetracycline, sulphonamide, streptomycin, neomycin, chloramphenicol, kanamycin, cefoperazone and gentamycin were used to test the antibiotic susceptibility for these Salmonella isolates, only three antibiogram patterns were obtained and 49 of the 55 Salm . typhi isolates were found to belong to one pattern . Phage typing and plasmid profiles were also poor in discriminating these strains . Thus, PFGE alone may be used as a powerful tool for analysis of sporadic associated Salm . typhi strains.

Can J Microbiol, 1998 Dec, 44(12), 1183 - 5
Computer-assisted restriction endonuclease analysis of plasmid DNA in field strains of Salmonella enteritidis; Rychlik I et al.; Computer-assisted restriction endonuclease analysis of plasmid DNA in field strains of Salmonella enterica serovar Enteritidis (S . enteritidis) is described . The procedure consists of plasmid DNA purification, its digestion with restriction endonuclease TaqI, electrophoresis, charge-coupled device camera scanning of the gels, and an analysis of the restriction patterns with the software Gel Manager . The system allowed us to analyse, in detail, results of plasmid profiling in more than 600 field strains of S . enteritidis . In addition to plasmid-free and virulence plasmid only containing strains, 15 additional plasmid types were detected . All the images and detailed protocols are available at the Web site http://www.clark.cz/vri/salmon.htm.

Hepatology, 1999 Jun, 29(6), 1799 - 808
The roles of intrahepatic Valpha14(+) NK1.1(+) T cells for liver injury induced by Salmonella infection in mice; Ishigami M et al.; To investigate the roles of intrahepatic T cells in liver injury after Salmonella infection, we examined serum alanine transaminase (ALT), histopathology, and bacterial numbers in liver after infection with Salmonella choleraesuis strain 31N-1 in mice genetically lacking TCRalpha beta+, CD4(+), CD8(+), or NK1.1(+)T cells with C57BL/6 background . In control (+/+) mice, serum ALT reached a peak level by day 7 after an intraperitoneal inoculation of 2 x 10(6) CFU Salmonella choleraesuis 31N-1 . In TCR-beta-/- mice, liver injury, as assessed by serum ALT level and histological examination, was significantly suppressed on day 7 after Salmonella infection but the numbers of bacteria in liver did not differ from those in normal mice, suggesting that alpha beta T cells are responsible for liver injury induced by Salmonella infection . To further determine which subsets in alpha beta T cells are important for the liver injury, we compared serum ALT level in mice genetically lacking CD4, CD8, beta2-microglobulin (beta2m, IAbeta, or Jalpha281 after Salmonella infection . In CD4(-/-) mice, serum ALT was significantly lower in comparison with control mice, but there was no difference in serum ALT levels in CD8(-/-) and IAbeta-/- mice from that in control mice . Notably, serum ALT levels and pathological lesions in liver were significantly decreased in beta2m-/- or Jalpha281(-/-) mice, which lacked in NK1.1(+) T cells bearing TCR Valpha14-Jalpha281 specific for beta2m-associated CD1d, following Salmonella infection . Taken together, it is suggested that alpha beta T cells bearing NK1.1 and CD4 may be main effector cells for liver injury after Salmonella infection.

Am J Trop Med Hyg, 1999 May, 60(5), 871 - 4
Diarrheal disease in patients infected with human immunodeficiency virus in Bangkok, Thailand; Wanke CA et al.; Diarrheal disease and its associated morbidities occur frequently in patients infected with human immunodeficiency virus (HIV) and may be associated with a decreased quality of life . We studied the spectrum of symptoms, measures of nutritional status, and the enteric pathogens associated with diarrheal disease in a group of 24 patients infected with HIV in Bangkok, Thailand compared with a group of 19 patients infected with HIV without diarrhea cared for at the same clinic . Patients with diarrhea appeared to have more advanced disease by CD4 cell counts and complained more frequently of symptoms such as anorexia, gas, and bloating than patients without diarrhea . Patients with diarrhea had a tendency toward a lower nutritional status, as measured by body mass index and mid arm circumference . Stool culture and examination revealed that enteric pathogens including Salmonella species and Cryptosporidium parvum sporidia were recovered at equal frequencies in patients with and without diarrhea (27% of the patients with diarrhea and 25% of the patients without diarrhea) . Microsporidia was identified in one patient with diarrhea . It was not possible to identify a pathogen in 73% of the patients with diarrhea and 75% of the patients without diarrhea, suggesting that additional agents or factors may be responsible for the diarrheal symptoms in the patients with diarrhea . More extensive studies to identify potentially treatable pathogens in HIV-infected patients with diarrhea in Thailand are warranted and further attempts to better define the syndrome of pathogen-negative diarrheal disease in patients infected with HIV might result in the development of more targeted interventions in these patients.

J Vet Med Sci, 1999 Apr, 61(4), 439 - 42
Epidemiological analysis of Salmonella enteritidis from human outbreaks by pulsed-field gel electrophoresis; Murakami K et al.; To determine the extent of genetic diversity among isolates of Salmonella enteritidis obtained from outbreaks in Fukuoka Prefecture, Japan, from 1989 to 1994, we analyzed a total of 55 isolates of S . enteritidis obtained from 13 distinct outbreaks with pulsed-field gel electrophoresis . These isolates showed three different patterns in pulsed-field profile with Bln I digestion . The groups A, B and C consisted of three outbreaks isolates (Dice coefficient, F = 1), of seven outbreaks (F = 0.56-0.94) and of three outbreaks (F = 0.65-0.78), respectively . This result suggests that a few limited clonal lines of S . enteritidis were successively causing outbreaks in this area from 1989 to 1994.

FEMS Immunol Med Microbiol, 1999 May, 24(1), 97 - 103
Role of interleukin-2 receptor expression on macrophages from Salmonella-infected mice; Matsui K; In this study, it was found that macrophages from Salmonella-infected mice expressed the interleukin-2 receptor (IL-2R) . The IL-2R induced by the infection consisted mainly of both beta and gamma chains, and the expression of IL-2Ralpha was very low . Furthermore, similar expression of IL-2Rbeta and gamma chains was observed in interferon-gamma-treated macrophages . The effect of recombinant interleukin-2 on the intracellular killing activity of macrophages which expressed IL-2Rbeta and gamma was then studied . Our results demonstrated that interleukin-2 acted synergistically with interferon-gamma through the IL-2R in the induction of macrophage intracellular killing activity and established a new role of IL-2R on bactericidal activity of macrophages.

J Food Prot, 1999 May, 62(5), 467 - 73
Incidence of Salmonella on beef carcasses relating to the U.S . meat and poultry inspection regulations; Sofos JN et al.; This article is part of a major study designed to collect baseline contamination data by sampling beef carcasses in seven slaughtering plants (four steer-heifer and three cow-bull plants) during both a dry season (November to January) and a wet season (May to June) . Samples (n = 30) were excised from each of three carcass anatomical sites (brisket, flank, and rump) at each of three points in the slaughtering chain (pre-evisceration, following final carcass washing, after 24-h carcass chilling) . A total of 3,780 samples (100 cm2 each) were analyzed for presence of Salmonella; aerobic plate counts, total coliform counts, and Escherichia coli counts were also made . After 24-h chilling, average incidence (expressed as a percentage) of Salmonella in the brisket, flank, and rump samples, respectively, for steer-heifer carcasses was 0.8+/-1.7, 0, and 2.5+/-5.0 for the wet season and 0.8+/-1.7, 0, and 0 for the dry season; the corresponding percentages for cowbull carcasses were 4.4+/-2.0, 2.2+/-3.9, and 1.1+/-1.9 for the wet season and 2.2+/-3.9, 1.1+/-1.9, and 0 for the dry season . Depending on plant and season, ranges of probabilities of chilled steer-heifer carcasses passing the U.S . regulatory requirements for Salmonella contamination were 0.24 to 1.0 for the brisket, 1.0 for the flank, and 0.002 to 1.0 for the rump; the corresponding ranges for the chilled cow-bull carcasses were 0.25 to 1.0, 0.25 to 1.0, and 0.70 to 1.0 . When the number of positive brisket, flank, and rump samples were combined, the probabilities of passing the regulatory requirements were 0.242 to 1.0 and 0.772 to 1.0 for the wet and dry seasons, respectively, in steer-heifer plants and 0.368 to 0.974 and 0.865 to 1.0 in cow-bull plants . Correlation coefficients of aerobic plate counts, total coliform counts, and E . coli counts with Salmonella incidence were higher (P< or =0.05) for cow-bull samples that had increased incidence of the pathogen when compared to steer-heifer samples.

J Am Vet Med Assoc, 1999 May 15, 214(10), 1511 - 6
Risk factors for nosocomial Salmonella infection among hospitalized horses; House JK et al.; OBJECTIVE: To identify risk factors for nosocomial Salmonella infections among hospitalized horses . DESIGN: Longitudinal study . ANIMALS: 1,583 horses hospitalized in an intensive care unit between January 1992 and June 1996 . PROCEDURE: Survivor functions were used to estimate time to shedding salmonellae for various Salmonella serotypes . Survival analysis was then used to determine how variables associated with patient management, environmental conditions, hospital conditions, and other disease processes affected the risk of nosocomial Salmonella infection . RESULTS: 78 horses shed Salmonella organisms: 35 shed Salmonella krefeld, 26 shed S typhimurium, and 17 shed other Salmonella serotypes . Mean time from admission to shedding was significantly longer for horses shedding S krefeld or S typhimurium than for horses shedding other Salmonella serotypes . Therefore, infection with S krefeld or S typhimurium was considered nosocomial . Seven variables were found to be significantly associated with risk of nosocomial Salmonella infection: mean number of horses in the hospital shedding S krefeld during the 4 days prior to and the day of admission, mean number of horses shedding S typhimurium during this period, a diagnosis of large colon impaction, withholding feed, number of days fed bran mash, duration of treatment with potassium penicillin G, and mean daily ambient temperature . CLINICAL IMPLICATIONS: Results suggest that risk of nosocomial Salmonella infections is greater for horses with large colon impactions . In addition to implementing hospital protocols that minimize cross contamination between patients, strategies to reduce the risk of nosocomial Salmonella infection should include minimizing use of potassium penicillin G and regulation of environmental temperature in the hospital.

An Med Interna, 1999 Apr, 16(4), 191 - 2
{Intravascular infection caused by Salmonella enteritidis}; de la Fuente Aguado J et al.; We report one case of salmonellosis aortitis in a 70 years old man after an episode of gastroenteritis due to Salmonella enteritidis successfully resolved with extraanatomic by-pass and prolonged antibiotic administration.

Microbiol Immunol, 1999, 43(3), 293 - 6
Genotypic characterization of human and environmental isolates of Salmonella choleraesuis subspecies choleraesuis serovar infantis by pulsed-field gel electrophoresis; Murakami K et al.; To determine the extent of genetic diversity of Salmonella choleraesuis subspecies choleraesuis serovar Infantis and whether environmental isolates were similar or identical to human isolates, a total of 110 isolates from humans, broiler samples, egg production facilities, riverwater, sewage, and chicken meat were analyzed epidemiologically by pulsed-field gel electrophoresis . While the isolates showed 35 distinct pulsed-field profiles, none had the genotype of the human isolates . One pulsed-field profile was shared by 43 (39%) of the 110 isolates . These results indicate that relatively fewer clonal lines of S . serovar Infantis had spread widely while multiple clonal lines, including the strain involved in the outbreak, exist in Western Japan.

Berl Munch Tierarztl Wochenschr, 1999 Apr, 112(4), 121 - 3
{Necessity of double testing of meat juice samples from pigs using ELISA for the determination of Salmonella status in pig farms}; Steinbach G et al.; According to the test protocol of the "meat juice ELISA" for detection of salmonella antibodies in pigs, all meat juice samples and serum controls are to be tested in duplicate . Results from routine investigations of repeatedly double tested meat juice and serum samples have been used to analyze the effect of double testing versus single testing with regard to the reliability of the final result . In case of an individual animal, testing of samples in duplicate increases the reliability of the results significantly, especially, if samples are retested at different occasions . In contrast, such a difference between mono and double testing of samples is not of importance when a group of animals is tested in order to determine the mean antibody rate in a herd . Here, results from double testing practically do not contribute to a higher reliability of the final result . This observation provides the possibility to reduce the costs for investigation programmes drastically.

J Immunother, 1999 May, 22(3), 251 - 9
Active specific immunotherapy for metastatic colorectal carcinoma: phase I study of an allogeneic cell vaccine plus low-dose interleukin-1 alpha; Woodlock TJ et al.; A vaccine consisting of four allogeneic colon carcinoma cell lines (DLD-1, HCT116, WiDr, and T84) mixed with the adjuvant DETOX (Mycobacterium phlei cell wall and Salmonella minnesota lipid A) was administered to 25 patients with low-volume metastatic colorectal carcinoma . The first eight patients received vaccine only, given intradermally on three occasions at 3-week intervals . Subsequent patients also received subcutaneous interleukin-1 alpha (IL-1 alpha), 0.3-0.5 microgram/m2 per day for 8 days after each vaccination in an outpatient setting . Vaccine alone caused local erythema, induration, and pruritus . IL-1 caused fevers, chills, and rigors that started in 4 h and lasted 1-2 h . One patient developed a brief loss of consciousness with a rigor that resolved without sequelae . One episode of mild hypotension occurred . Fatigue occurred by day 8 of IL-1 . A substantial increase in the number of patients with positive skin tests to DLD-1 and HCT116 occurred after vaccine treatment both without and with IL-1 alpha . An allogeneic cell vaccine plus subcutaneous IL-1 was administered safely to outpatients with some evidence of in vivo effect observed.

Environ Mol Mutagen, 1999, 33(3), 226 - 39
Computer-aided analysis of mutagenicity and cell transformation data for assessing their relationship with carcinogenicity; Taningher M et al.; Using a computer-aided approach, the tests for Salmonella mutagenicity and transformation in established cell lines were compared for the qualitative bases of their carcinogenicity predictions . For this purpose, a database of 145 chemicals was prepared in which rodent carcinogenicity data and results of the Ames' and transformation tests were available . Using a software program for connectivity analysis (previously developed and validated by us), we assayed the molecular structures of these chemicals for the presence of fragments relatable to their positive (i.e., biophores) or negative (i.e., biophobes) response to the tests in question . These fragments were then studied for their association with genotoxic and nongenotoxic carcinogenicity . The philosophy adopted was that the type and number of molecular fragments chosen by the software to describe the chemicals correctly predicted by the tests could be related to the type of carcinogenic effects to which the tests themselves were sensitive . The classifications made by the software were interpreted by human expertise and the biophores found were compared with the acknowledged structural alerts to DNA reactivity as formalized by Ashby and co-workers {(1991): Mutat Res 257:229-306; (1993): Mutat Res 286: 3-74} . The results show that, in quantitative terms, the overall ability to predict carcinogenicity is about the same for both the Salmonella and transformation tests . However, in qualitative terms the transformation test appears to be sensitive to effects that are more heterogeneous than those inducing mutation, some of which are presumably related to nongenotoxic carcinogenic activities . This study illustrates a possible, innovative model of analysis of chemical structures that, using an automated approach along with the biologist's judgment, could contribute to the detection of complementarities among short-term test endpoints.

Environ Mol Mutagen, 1999, 33(3), 185 - 93
Mutation spectrum in Salmonella induced by environmental tobacco smoke; Zhou R et al.; Environmental tobacco smoke (ETS) is a major source of indoor air pollution . Extractable-respirable particulate (ERP) from the ETS-contaminated indoor air (ERP-ETS) was collected from six passenger train cars and one control room . The mutagenicity of ERP-ETS was tested in the Ames/Salmonella test in the presence of male rat liver microsomal fraction S9 . The mutation spectrum of ERP-ETS was determined by colony probe hybridization and polymerase chain reaction/DNA sequence analysis in approximately 2,370 His+ revertants . The results indicate that the majority of ERP-ETS-induced mutations were a two-base deletion of GC or CG within the hotspot sequence of CGCGCGCG at the frameshift hisD3052 allele in strain TA98 . The ERP-ETS from the control room induced approximately 94.3% such deletions, while the ERP-ETS collected from the passenger cars induced approximately 89.6% such deletions . The ERP-ETS either from the control room or from the passenger cars induced approximately 74% C/G --> A/T transversions, and approximately 23% C/G --> T/A transitions within the primary target CCC at the hisG46 allele in strain TA100.

J Med Microbiol, 1999 Mar, 48(3), 253 - 61
Effect of pH, temperature and surface contact on the elaboration of fimbriae and flagella by Salmonella serotype Enteritidis; Walker SL et al.; Survival of enteric pathogens exposed to various environmental stresses depends upon a number of protective responses, some of which are associated with induction of virulence determinants . Flagella and fimbriae are putative virulence determinants of Salmonella spp . and ELISAs specific for the detection of flagella and SEF21, SEF14 and SEF17 fimbriae were used to assess the effect of temperature and pH upon their elaboration by isolates of Salmonella serotype Enteritidis in planktonic growth and on the surface of two-dimensional gradient agar plates . For three phage type 4 isolates of Enteritidis of comparative clinical provenance, similar phenotypes for the elaboration of these surface antigens were observed . SEF14 fimbriae were elaborated in planktonic growth at 37 degrees C, but not 20 degrees C, at pH 4.77 and above but not at pH 4.04; whereas on agar gradient plates SEF14 fimbriae were elaborated poorly but with best yields at pH 4.04 . SEF17 fimbriae were elaborated in planktonic growth at 20 degrees C, but not at 37 degrees C, at pH 6.18 and above but not at pH 5.09 or below; whereas on agar gradient plates SEF17 fimbriae were elaborated well even at pH 4.65 . SEF21 fimbriae were expressed very poorly under all conditions tested . Planktonic growth at 37 degrees C induced least flagella whereas growth at 20 degrees C, and particularly surface growth at lower pH values, induced a 'hyper-flagellate' phenotype . Single colonies allowed to form on gradient agar plates were shown to generate different colonial morphologies which were dependent on initial pH . These results demonstrate that the physicochemical environment is an important determinant of bacterial response, especially the induction of putative virulence factors.

J Microbiol Methods, 1999 Apr, 35(3), 219 - 23
Preparation of a high titre Salmonella abortusovis H-antigen and antiserum and improvement of the microagglutination test; Giannati A et al.; Serological diagnosis of small ruminant abortions due to Salmonella abortusovis (S.a.o) was improved by using modified procedures to produce high titre H-antigens and anti-H serum . While the titres of the two standard antigens were 1:8 and 1:20, both modified antigens had a titre of 1:50 . Similarly, the use of adjuvanted and non adjuvanted antigens for the production of anti-H hyperimmune serum resulted in a titre of 1:160,000 as compared to 1:20,000 when standard procedures were used . In addition, the slow micro-agglutination test has been modified and results can now be read within the same day.

J Vet Med Sci, 1999 Mar, 61(3), 255 - 9
Prevalence and persistence of Salmonella in broiler chicken flocks; Limawongpranee S et al.; Cecal contents of 2,345 broiler chickens consisting of 28 flocks originated from 12 farms were examined for the prevalence of Salmonella to know the actual status of infection with Salmonella in the chicken flocks . Salmonella was isolated from 336 (14.3%) samples . From these isolates, eight serovars were identified . Of the 336 Salmonella isolates, 242 (72.0%) were serotyped as S . Blockley, 60 (17.9%) S . Hadar, 15 (4.5%) S . Bredeney, nine (2.7%) S . Schwarzengrund, four (1.2%) S . Anatum, three (0.9%) S . Enteritidis, two (0.6%) S . Ohio, and one (0.3%) S . Livingstone . The same serovars of Salmonella were repeatedly found in the chickens from the same farms . S . Typhimurium and S . Enteritidis were detected in pooled broken eggshell samples collected from the hatchery . Analysis of plasmid profiles revealed 11 patterns of S . Blockley and seven patterns of S . Hadar . Strains of the same plasmid profiles of S . Blockley were isolated repeatedly from the same farm over one year after the first isolation.

Kaohsiung J Med Sci, 1999 Apr, 15(4), 202 - 8
Salmonella choleraesuis bacteremia in southern Taiwan; Chen YH et al.; Within a 6-year period from January 1991 to December 1996, 19 patients with Salmonella choleraesuis bacteremia were enrolled for clinical and microbiological analysis . Young children, the elderly and patients with hematological malignancy (36.8%), liver cirrhosis (26.3%), systemic lupus erythematosus (10.5%), chronic renal impairment (10.5%), and peptic ulcer (10.5%) were at high risk of this infection . The ratio of male to female was 3:1 . Three cases (15.8%) were nosocomially acquired . Fever (89.5%), chills (57.9%) and anorexia (52.6%) were the most common clinical manifestations . Seven patients (36.8%) presented no gastrointestinal manifestations . Normal white blood cell count was noted in seven patients (36.8%), and neutropenia caused by underlying diseases or severe infection was found in six cases (31.6%) . Various types of metastatic focal infections were found, such as septic arthritis, cutaneous infection, spontaneous bacterial peritonitis, and pneumonia . The severe immunocompromised status of patients and the high virulence of this pathogen may contribute to the high case fatality rate (21%) . Higher resistance rate to commonly used antimicrobial agents was noted in ampicillin (94.7%), chloramphenicol (89.5%), and TMP/SMZ (63.8%) . All strains of S . choleraesuis were susceptible to third-generation cephalosporins and fluoroquinolones . Generally, S . choleraesuis bacteremia should be taken into account in the differential diagnosis of sepsis in immunocompromised patients, even without gastrointestinal manifestations . The third-generation cephalosporins and fluoroquinolones may be the first choice for treatment of this invasive infections.

Prev Vet Med, 1999 Apr 27, 39(4), 265 - 77
Risk factors for Salmonella enterica subsp . enterica contamination in French broiler-chicken flocks at the end of the rearing period; Rose N et al.; Broiler-chicken are often Salmonella carriers . However, these bacteria are responsible for major food-borne human infection, in which poultry-meat products are frequently implicated . In order to prevent Salmonella spread during the slaughtering process, control measures should be implemented at the farm level to reduce the prevalence before slaughtering . The objective of this study was to identify the risk factors for Salmonella contamination in French commercial broiler flocks at the end of the rearing period . A prospective study was carried out in 1996 and 1997 on 86 broiler flocks located in western France . The Salmonella status of the flocks was assessed by means of litter swabs and dust samples analyzed with classical bacteriological methods . Sixty flocks (70%) had at least one contaminated environmental sample and were classified as Salmonella-contaminated flocks . Logistic regression was used to assess association of managerial practices, general hygiene and results of environmental Salmonella recovery, with the odds that the flock itself would be Salmonella-contaminated at the end of the rearing period . Salmonella contamination of the house before placing day-old chicks and the Salmonella contamination of day-old chicks were significantly related to Salmonella contamination of the flock at the end of the rearing period . The risk for Salmonella contamination of the flock was increased when feed trucks parked near the entrance of the change room and when feed meal, instead of small pellets, was provided at the start.

Prev Vet Med, 1999 Apr 9, 39(3), 211 - 25
Comparison of methods for estimation of individual-level prevalence based on pooled samples; Cowling DW et al.; We review frequentist and Bayesian approaches for estimating animal-level disease prevalence using pooled samples obtained by simple random sampling . We determine the preferred approach for different prevalence scenarios and with varying knowledge about sensitivity and specificity values . When sensitivity and specificity are perfect or known, we can choose between the large-sample theory estimates and the one-to-one relationship exact estimates . When sensitivity and specificity are unknown, we must use large-sample theory estimates or Bayesian methodology (which gives exact estimates) . However, when the large-sample theory produces a negative lower confidence limit, we must use one of the exact methods . We compare estimates from each approach using culture results from pools of 20 eggs from three flocks on a California ranch that were producing eggs that were contaminated with Salmonella enteritidis phage type 4.

Wei Sheng Yan Jiu, 1997 May, 26(3), 208 - 10
{Research on types of Salmonella in some animals in Jilin province}; Liu G et al.; Some animals were examined for the presence of Salmonella in Jilin province . The rate of Salmonella detection was 537 strains from 846 snakes samples (63.5%); 136 strains from 648 frog samples (20%); 185 strains from 369 pig and chick samples (50%) . All isolated Salmonella comprised of two subgenus (SII and SIIIb) . Serologically, groups 04, 07, 08, 09, 01, 03, 19, 03, 10, 016, 035, 043, 048, 050, 058 and 061 were identified and the isolates were classified into 13 groups and 24 serotypes . Two of these isolates SII43:enZ15:1, 6 and SIIIb58:Z52:Z are reported for the first time in China.

J Clin Microbiol, 1999 Jun, 37(6), 2058 - 60
Typing of Salmonella enterica serotype paratyphi C isolates from various countries by plasmid profiles and pulsed-field gel electrophoresis; Kariuki S et al.; Pulsed-field gel electrophoresis (PFGE) of 61 Salmonella enterica serotype Paratyphi C isolates from six countries gave five distinct clusters . Twenty-four isolates from five countries were susceptible to 10 antimicrobials tested and gave similar restriction endonuclease digest patterns of the 38-MDa plasmid . In contrast, plasmid and PFGE profiles of 37 multidrug-resistant isolates from Zaire were different from those from other countries.

J Clin Microbiol, 1999 Jun, 37(6), 1687 - 92
Assessment of strain relatedness among Salmonella serotypes Salinatis, Duisburg, and Sandiego by biotyping, ribotyping, IS200 fingerprinting, and pulsed-field gel electrophoresis; Old DC et al.; Salinatis (antigenic formula, 4,12:d:eh:enz15) is a rare Salmonella serotype currently designated a triphasic variant of the diphasic serotype Duisburg (1,4,12,27:d:enz15) (underlining indicates that the O antigen is determined by phage lysogenization) . Salinatis could also be related to serotype Sandiego (4,{5},12:eh:enz15), from which it might have been derived by loss of H-d flagellin genes . Nineteen Salmonella strains of serotypes Salinatis, Duisburg, and Sandiego were examined by biotyping, PvuII and SmaI ribotyping, IS200 fingerprinting, and pulsed-field gel electrophoretic profiling . Results from these methods, used alone or together, indicate that serotype Salinatis is more likely to be related to serotype Sandiego than to serotype Duisburg . For future lists of serotype names, it is recommended that Salinatis be considered a variant of Sandiego.

Arthritis Rheum, 1999 May, 42(5), 1056 - 61
Systemic lupus erythematosus-associated catastrophic antiphospholipid syndrome occurring after typhoid fever: a possible role of Salmonella lipopolysaccharide in the occurrence of diffuse vasculopathy-coagulopathy; Hayem G et al.; We report a case of well-documented typhoid fever in a 30-year-old woman with inactive systemic lupus erythematosus with asymptomatic lupus anticoagulant and high-titer anticardiolipin antibody (aCL) . Despite prompt eradication of the Salmonella typhi obtained with appropriate antibiotic therapy, multiple organ system dysfunction occurred . The central nervous system was involved, with ischemic infarcts in the occipital lobes . High-dose corticosteroid therapy failed to improve the neurologic manifestations, which responded to repeated plasmapheresis . A sharp fall in aCL and anti-beta2-glycoprotein I antibody titers was recorded before the start of plasmapheresis . At the same time, IgM and IgG antibodies to Salmonella group O:9 lipopolysaccharide became detectable; the IgM antibodies disappeared within 4 months, whereas the IgG antibodies remained detectable during the next 13 months . Despite treatment with high-dose corticosteroids and cyclophosphamide, rapidly progressive glomerulonephritis developed, leading to chronic renal failure . There is convincing evidence of a link between the S . typhi infection and the ensuing catastrophic syndrome in this patient, probably precipitated by bacterial antigens.

New Microbiol, 1999 Apr, 22(2), 129 - 38
Uptake and retention of Vibrio cholerae non-O1, Salmonella typhi, Escherichia coli and Vibrio harvey by mussels in seawater; Marino A et al.; Vibrio cholerae non O1 is known to persist in estuarine and freshwater environments . Experiments evaluated the amount of microorganisms accumulated in mussels maintained in static seawater, contaminated with 10(4) to 10(6) cells/ml and the depuration time required in circulating water . Accumulation and retention times were compared with those for Escherichia coli, Salmonella typhi and Vibrio harvey . E . coli and S . typhi accumulated to a greater extent and were released from mussels more quickly than vibrios which became undetectable 2 to 3 days later than E . coli . Seasonal seawater temperatures (14 to 21 degrees C) had a limited influence on depuration but vibrios appear to be retained with more efficacy over 16 degrees C while E . coli and S . typhi were eliminated to a greater extent . When mussels were contaminated with mixed culture, vibrios appeared to predominate on E . coli, while no interference was observed between E . coli and S . typhi.

Immunopharmacol Immunotoxicol, 1999 May, 21(2), 307 - 30
Enhancement of cellular and humoral immunity in young broilers by the dietary supplementation of beta-hydroxy-beta-methylbutyrate; Peterson AL et al.; As a dietary supplement, beta-Hydroxy-beta-Methylbutyrate (HMB), a catabolite of leucine, has been shown to reduce broiler mortality . In a series of experiments, male broilers (Experiments 1 and 2, n = 576) were grown for 21 days on diets that contained HMB at 0, 0.01 . 0.05, and 0.10% of diet . In Experiment 3 (n = 240), chicks were fed diets containing 0, 0.05, 0.075, and 0.10% HMB . HMB dietary supplementation did not significantly affect broiler weight gain in any experiment . However, a trend toward increased mean broiler weight gain per bird was observed in Experiments 1 and 3 when HMB was consumed at 0.10% of the diet . Mean feed to gain ratio was not affected by the inclusion of HMB in broiler diets . In Experiment 3, HMB supplemented diets did not affect bursa of Fabricius, thymus, and spleen weights at 21 days of age . Cutaneous basophilic hypersensitivity response against pokeweek mitogen was higher (P < or = 0.05) at 48 and 72 hours post-injection in chicks on 0.05% dietary HMB (Experiment 1) . In Experiment 2, this increase occurred 24 hours post-injection in chicks fed HMB at 0.01% of the diet . On the contrary, the T-cell mediated response against PHA-P mitogen was comparable between all dietary treatments in multiple experiments . Macrophage function profiles were determined at 21 days of age . All chicks in experiments 1 and 2 on HMB supplemented diets showed an increase in the recruitment of Sephadex-G50-elicited abdominal exudate cells (AEC) . A 2-fold increase in AEC numbers occurred at the 0.10% HMB level (Experiment 1, P < or = 0.05) . Although HMB supplementation did not significantly affect the phagocytic potential of the abdominal macrophages, nitrite levels in the macrophage culture supernatants were higher in 0.01% and 0.05% treatment groups as compared to the controls (Experiment 2, P < or = 0.04; Experiment 3, P < or = 0.05) . HMB supplementation did not alter the bird's ability to clear Escherichiacoli or Salmonella arizona from the bloodstream . Beginning 7 days post-hatch, chicks were injected i.v . with a 7% sheep red blood cells suspension . Serum samples were collected to determine the primary and secondary antibody response . Chicks receiving the 0.1% HMB diet in Experiments 1 and 2 exhibited increased IgG and total anti-sheep red blood cell (SRBC) antibody levels during the primary response . During the secondary response, birds consuming the 0.10% HMB diet had elevated IgM levels as well as increased total anti-SRBC levels over the controls in Experiments 1 and 3 . These studies show that HMB supplementation improves several immunological functions in young broilers, and such improvement may result in decreased mortality.

Mol Microbiol, 1999 May, 32(3), 629 - 42
Two AraC/XylS family members can independently counteract the effect of repressing sequences upstream of the hilA promoter; Schechter LM et al.; During infection of its hosts, Salmonella enterica serovar Typhimurium (S . typhimurium) enters the epithelial cells of the small intestine . This process requires a number of invasion genes encoded on Salmonella pathogenicity island 1 (SPI1), a 40 kb stretch of DNA located near minute 63 of the S . typhimurium chromosome . Expression of S . typhimurium SPI1 invasion genes is activated by the transcription factor HilA . hilA is tightly regulated in response to many environmental conditions, including oxygen, osmolarity and pH . Regulation of hilA expression may serve to limit invasion gene expression to the appropriate times during Salmonella infection . We have mapped the transcription start site of hilA and identified regions of the promoter that are required for the repression of hilA expression by conditions unfavourable for Salmonella invasion . We have also identified two SPI1-encoded genes, hilC and hilD, that can independently derepress hilA expression . HilC and HilD are both members of the AraC/XylS family of transcriptional regulators . A mutation in hilD significantly reduces the ability of S . typhimurium to enter tissue culture cells, whereas a mutation in hilC only modestly affects Salmonella invasion . Based on these results, we have updated our model of Salmonella SPI1 invasion gene regulation . We also speculate on the possible significance of this model for Salmonella pathogenesis.

Int J Syst Bacteriol, 1999 Apr, 49 Pt 2, 927 - 30
Revised Salmonella nomenclature: designation of Salmonella enterica (ex Kauffmann and Edwards 1952) Le Minor and Popoff 1987 sp . nov., nom . rev . as the neotype species of the genus Salmonella Lignieres 1900 (approved lists 1980), rejection of the name Salmonella choleraesuis (Smith 1894) Weldin 1927 (approved lists 1980), and conservation of the name Salmonella typhi (Schroeter 1886) Warren and Scott 1930 (approved lists 1980) . Request for an opinion; Euzeby JP; The Request for an Opinion by Le Minor and Popoff 1987, proposing designation of 'Salmonella enterica' (ex Kauffman and Edwards 1952) Le Minor and Popoff 1987 as the type and only species of the genus Salmonella Lignieres 1900 (Approved Lists 1980), has not been positively decided upon by the Judicial Commission . However, many bacteriologists use the name 'Salmonella enterica' . To avoid further confusion, it is requested to reject the name Salmonella choleraesuis (Smith 1894) Weldin 1927 (Approved Lists 1980), to recognize the species Salmonella enterica, to conserve the name Salmonella typhi (Schroeter 1886) Warren and Scott 1930 (Approved Lists 1980), and to emend the genus Salmonella with the establishment of a neotype species, Salmonella enterica.

Immunol Cell Biol, 1999 Apr, 77(2), 143 - 52
Suppressive effects of serum on the LPS-induced production of nitric oxide and TNF-alpha by a macrophage-like cell line, WEHI-3, are dependent on the structure of polysaccharide chains in LPS; Ohki K et al.; The effect of serum on LPS-induced activation of a murine macrophage-like cell line, WEHI-3, was examined . Foetal calf serum strongly inhibited the production of nitric oxide (NO) and TNF-alpha by LPS-stimulated WEHI-3 cells, while it enhanced the production of both by other macrophage-like cell lines, J774.1 and BAM3, on treatment with LPS . This suppressive effect of serum on WEHI-3 cells was most remarkable when the cells were stimulated with rough-chemotype LPS, Ra LPS, Rc LPS and Rd2 LPS . Foetal calf serum also inhibited TNF-alpha production by the same cells stimulated with high concentrations of smooth-form LPS (S LPS; > 1000 ng/mL) . Serum-mediated suppression was also observed for expression of the TNF-alpha gene in Rc LPS-stimulated WEHI-3 cells . This suppressive effect of FCS was most remarkable during the 1-2 h before the addition of LPS, but it was not observed when FCS was added at 1 h after the addition of LPS, suggesting dependence on the time of FCS addition to LPS-stimulated cells . No significant difference was observed in the expression of CD14 on WEHI-3 cells cultured in the presence and absence of serum, suggesting that CD14 is not involved in the serum-mediated suppression of these LPS-responses . On the contrary, FCS showed enhancing effects on the production of NO and TNF-alpha by WEHI-3 cells stimulated with low concentrations (< 100 ng/mL) of S LPS and rough mutant Salmonella minnesota Re LPS . These results suggest that the ability of FCS to suppress LPS-induced activation of WEHI-3 cells in mainly dependent on the structure of polysaccharide chains and also on the concentration of LPS employed.

Eur J Immunol, 1999 Apr, 29(4), 1107 - 15
Salmonella efficiently enter and survive within cultured CD11c+ dendritic cells initiating cytokine expression; Marriott I et al.; While Salmonella infects macrophages, this cell population may not be the only one important for disseminating intracellular bacteria from mucosal sites . Dendritic cells (DC) are present in the Peyer's patches and are mobilized following stimulation . Such characteristics would seem to be ideal for the dissemination of an intracellular, mucosal pathogen . However, it has been difficult to obtain sufficient numbers of DC to assess their ability to harbor Salmonella or to monitor DC in vivo . In the present study, this problem has been addressed by expanding DC in vivo using flt3 ligand, followed by the purification of CD11c+ cells using antibody-coated magnetic beads or by fluorescence-activated cell sorting . Salmonella dublin were found to be efficiently internalized, and to survive and replicate within purified CD11c+ DC, and also in CD11c+, CD8alpha+ or CD11c+, CD11b+ DC subpopulations . The ability of Salmonella to enter DC is of similar magnitude to that reported for macrophages, suggesting that this cell population could be an important host cell for dissemination of this pathogen from mucosal sites . Furthermore, infected DC responded to Salmonella by secretion of IL-1, IL-6 and IL-12 . As such, these cells may be important sources of these cytokines during the host response against Salmonella infection.

J Infect Dis, 1999 Jun, 179(6), 1553 - 6
Zidovudine therapy protects against Salmonella bacteremia recurrence in human immunodeficiency virus-infected patients; Casado JL et al.; Fifty-five human immunodeficiency virus-infected patients with Salmonella bacteremia were studied to assess the rate of and causes for recurrence and to determine the influence on relapse of zidovudine, cotrimoxazole, and antimicrobial suppressive therapy according to the susceptibility of the isolates . Overall, 22% of patients relapsed in a median time of 87 days, independent of CD4 cell count, Salmonella serotype, or duration of antibiotic therapy . The use of zidovudine was associated with the lowest rate of recurrences compared with cotrimoxazole or amoxicillin as suppressive therapy . In the microbiologic assay, zidovudine showed bactericidal effect on Salmonella species at current dosages, and resistance to zidovudine was uncommon (2 cases, 4%) . Due to its direct effect on Salmonella species, a zidovudine-containing regimen may protect against the recurrence of the disease.

Food Chem Toxicol, 1999 Feb-Mar, 37(2-3), 125 - 34
Mutagenicity and aromatic amine content of fumes from heated cooking oils produced in Taiwan; Chiang TA et al.; According to toxicological studies, there are several unidentified mutagens derived from cooking oil fumes appearing in kitchens of Chinese homes where women daily prepare food . Data are limited to an analysis of aromatic amines from cooking oil fumes, which are known to be carcinogenic for bladder cancer . Fume samples from three different commercial cooking oils frequently used in Taiwan were collected and analysed for mutagenicity in the Salmonella/microsome assay . Aromatic amines were extracted from the samples and identified by HPLC and confirmed by gas chromatography/mass spectrometry (GC/MS) . Extracts from three cooking oil fumes were found to be mutagenic in the presence of S-9 mix . All samples contained 2-naphthylamine (2-NA) and 4-aminobiphenyl (4-ABP) . Concentrations of 2-NA and 4-ABP were 31.5 and 35.7 microg/m3 in fumes from sunflower oil, 31.9 and 26.4 mg/m3 in vegetable oil, and 48.3 and 23.3 microg/m3 in refined-lard oil, respectively . Mutagenicities of the three cooking oil condensates were significantly reduced (P<0.05) by adding the antioxidant catechin (CAT) into the oils before heating . Significant difference existed between the amounts of aromatic amines with and without adding CAT (P<0.05) . These results indicate that exposure to cooking oil fumes in Taiwan might be an important but controllable risk factor in the aetiology of bladder cancer.

Curr Biol, 1999 Apr 22, 9(8), R277 - 80
Bacterial invasion: Force feeding by Salmonella; Brumell JH et al.; Recent findings have shed new light on mammalian-cell invasion by Salmonella . Using a type III secretion system, Salmonella deliver virulence factors into the host cell that directly activate signal transduction pathways, initiating cytoskeletal rearrangements and bacterial uptake by a ruffling mechanism.

Infect Immun, 1999 May, 67(5), 2575 - 84
Host cell death due to enteropathogenic Escherichia coli has features of apoptosis; Crane JK et al.; Enteropathogenic Escherichia coli (EPEC) is a cause of prolonged watery diarrhea in children in developing countries . The ability of EPEC to kill host cells was investigated in vitro in assays using two human cultured cell lines, HeLa (cervical) and T84 (colonic) . EPEC killed epithelial cells as assessed by permeability to the vital dyes trypan blue and propidium iodide . In addition, EPEC triggered changes in the host cell, suggesting apoptosis as the mode of death; such changes included early expression of phosphatidylserine on the host cell surface and internucleosomal cleavage of host cell DNA . Genistein, an inhibitor of tyrosine kinases, and wortmannin, an inhibitor of host phosphatidylinositol 3-kinase, markedly increased EPEC-induced cell death and enhanced the features of apoptosis . EPEC-induced cell death was contact dependent and required adherence of live bacteria to the host cell . A quantitative assay for EPEC-induced cell death was developed by using the propidium iodide uptake method adapted to a fluorescence plate reader . With EPEC, the rate and extent of host cell death were less that what has been reported for Salmonella, Shigella, and Yersinia, three other genera of enteric bacteria known to cause apoptosis . However, rapid apoptosis of the host cell may not favor the pathogenic strategy of EPEC, a mucosa-adhering, noninvasive pathogen.

Int J Infect Dis, 1998-99 Winter, 3(2), 105 - 8
Typhoid fever and HIV infection: a rare disease association in industrialized countries; Manfredi R et al.; Typhoid fever is still a global health problem, mainly in tropical and subtropical areas of the world and in developing countries, where relatively elevated morbidity and mortality rates still are present, mostly because of persisting poor hygienic conditions . In the majority of Mediterranean regions, including Italy, the disease is constantly present, though with a low prevalence rate, as a result of an endemic persistence of Salmonella typhi infection.1-4 On the other hand, in industrialized countries, most cases of S . typhi infection are related to foreign travel or prior residence in endemic countries.4-6 In the United States, 2445 cases of typhoid fever have been reported in the decade 1985 to 1994, and the annual number of cases remained relatively stable over time: over 70% of episodes were acquired in endemic countries (mostly Mexico and India).6 The persisting morbidity of S . typhi also may be supported by the increasing resistance rate of this pathogen against a number of commonly used antimicrobial compounds . For instance, 6% of 331 evaluable S . typhi strains were resistant to ampicillin, chloramphenicol, and cotrimoxazole, and 22% of isolates were resistant to at least one of these three agents in a recent survey performed in the United States.6 The spread of antibiotic resistance among S . typhi isolates is emerging in many countries, and multidrug-resistant strains have been isolated, as well as isolates with poor susceptibility to fluoroquinolones,3-5,7-9 so that in vitro susceptibility should be determined for all cultured strains, and antimicrobial treatment should be adjusted accordingly . Nevertheless, fluoroquinolones (e.g., ciprofloxacin and pefloxacin) or third-generation cephalosporins, still represent the best choice for empirical treatment,2,4,6-8,10 and mortality remains rare in Western countries (less than 1% of episodes), although it is expected to be greater in developing areas of the world . The aim of this report is to describe two cases of typhoid fever that occurred in patients with human immunodeficiency virus (HIV) infection, a rarely reported disease association in industrialized countries.

Infect Immun, 1999 May, 67(5), 2611 - 4
Comparative physical and genetic maps of the virulence plasmids of Salmonella enterica serovars typhimurium, enteritidis, choleraesuis, and dublin; Chu C et al.; Using fragment profiling, PCR, and Southern hybridization, we found that Salmonella enterica serovar Choleraesuis harbored virulence plasmids of various sizes, whereas serovars Typhimurium, Enteritidis, and Dublin carried a plasmid of a unique size . Also, the virulence plasmid of Typhimurium contained genes in the same order detected in the other three plasmids, all of which contained deletions.

Scand J Infect Dis, 1998, 30(6), 632 - 4
Brain abscess caused by Salmonella enteritidis in an immunocompetent adult patient: successful treatment with cefotaxime and ciprofloxacin; Bonvin P et al.; A previously healthy 43-y-old man, who had spent 2 weeks in northern India, was admitted to hospital after a 2-day history of pyrexia, confusion and frontal headache . Cranial computerized tomography (CT) showed an abscess in the right parietal lobe . Spinal fluid and blood cultures gave growth of Salmonella enteritidis within 24 h . Treatment with cefotaxime was initiated, but ceased after 3 weeks due to drug fever, and ciprofloxacin was then given orally for 4 months . After 6 months, the patient was considered cured . Cases of salmonella brain abscesses are reviewed.

Indian J Physiol Pharmacol, 1998 Apr, 42(2), 223 - 30
Role of bio-metal Fe(III) in anticancer effect of dacarbazine; Shukla J et al.; Physicochemical, Microbial and Pharmacological studies on Fe(III)-Dacarbazine complex have been done in solid and aqueous phase . On the basis of elemental analysis, polarographic studies, amperometric titrations and IR spectral studies the probable formula for the complex has been worked out to be 1:1, Fe(III)-Dacarbazine . The metal ligand interaction has been studied using polarographic method at 25 +/- 1 degrees C and at ionic strength of mu = 1.0 (KCl) . Microbial studies on the complex was done against various pathogenic bacteria viz . Pseudomonas mangiferae, Staphylococcus aureus, Salmonella typhi and Vibrio cholarae and fungi i.e . Trichothecium and Chrysosporium sp . using Raper's method . Mouse sarcoma cell line 180 and Balb/C mice were used for the anticancer screening of solid complex in vitro and in vivo respectively . The observed polarographic data, on lingane treatment revealed the formation of single (1:1) (M:L) complex with Fe(III) and dacarbazine ligands . The results of amperometric titrations of Fe(III) with dacarbazine in IM KCl supporting electrolyte pH 7.0 +/- 0.1 supported the above findings the IR data speaks of the complex formation between the metal and the dacarbazine ligand through the two nitrogen one each of primary amide and trizo groups . The results of microbial and pharmacological studies with the M:Drug complex revealed that the anticancer activity of the drug metal complex is nearly doubled as compared to the pure drug . As such Fe(III) dacarbazine complex may be recommended to the therapeutic experts for its possible use as more potent anticancer drug.

Appl Environ Microbiol, 1999 May, 65(5), 2235 - 7
Detection of Salmonella spp . and Listeria monocytogenes in suspended organic waste by nucleic acid extraction and PCR; Burtscher C et al.; A nucleic acid-based method for the detection of the bacterial pathogens Salmonella spp . and Listeria monocytogenes in biological waste was developed . The detection limits were less than 10 cells per ml of biological waste . The method does not include a phenol extraction step and can be easily performed in 1 to 2 days.

Appl Environ Microbiol, 1999 May, 65(5), 2195 - 201
Clinical and veterinary isolates of Salmonella enterica serovar enteritidis defective in lipopolysaccharide O-chain polymerization; Guard-Petter J et al.; Twelve human and chicken isolates of Salmonella enterica serovar Enteritidis belonging to phage types 4, 8, 13a, and 23 were characterized for variability in lipopolysaccharide (LPS) composition . Isolates were differentiated into two groups, i.e., those that lacked immunoreactive O-chain, termed rough isolates, and those that had immunoreactive O-chain, termed smooth isolates . Isolates within these groups could be further differentiated by LPS compositional differences as detected by gel electrophoresis and gas liquid chromatography of samples extracted with water, which yielded significantly more LPS in comparison to phenol-chloroform extraction . The rough isolates were of two types, the O-antigen synthesis mutants and the O-antigen polymerization (wzy) mutants . Smooth isolates were also of two types, one producing low-molecular-weight (LMW) LPS and the other producing high-molecular-weight (HMW) LPS . To determine the genetic basis for the O-chain variability of the smooth isolates, we analyzed the effects of a null mutation in the O-chain length determinant gene, wzz (cld) of serovar Typhimurium . This mutation results in a loss of HMW LPS; however, the LMW LPS of this mutant was longer and more glucosylated than that from clinical isolates of serovar Enteritidis . Cluster analysis of these data and of those from two previously characterized isogenic strains of serovar Enteritidis that had different virulence attributes indicated that glucosylation of HMW LPS (via oafR function) is variable and results in two types of HMW structures, one that is highly glucosylated and one that is minimally glucosylated . These results strongly indicate that naturally occurring variability in wzy, wzz, and oafR function can be used to subtype isolates of serovar Enteritidis during epidemiological investigations.

Antimicrob Agents Chemother, 1999 May, 43(5), 1098 - 104
Integron- and carbenicillinase-mediated reduced susceptibility to amoxicillin-clavulanic acid in isolates of multidrug-resistant Salmonella enterica serotype typhimurium DT104 from French patients; Poirel L et al.; Fifty-seven Salmonella enterica serotype Typhimurium (S . typhimurium) isolates were collected from human patients in two French hospitals, Hopital Antoine Beclere (Clamart, France) and Hopital Bicetre (Le Kremlin-Bicetre, France), between 1996 and 1997 . Thirty of them (52 percent) were resistant to amino-, carbeni-, and ureidopenicillins, had reduced susceptibility to amoxicillin-clavulanic acid, were susceptible to cephalothin, and were resistant to sulfonamides, streptomycin, chloramphenicol, and tetracyclines . All these strains possessed a blaPSE-1-like gene and were of phage type DT104 . Ten of them were studied in more detail, which revealed that blaPSE-1 is located on the variable region of a class 1 integron . This integron was found to be chromosomally located, as was another class 1 integron containing aadA2, a streptomycin-spectinomycin resistance gene . The reduced susceptibility to amoxicillin-clavulanic acid (and to ticarcillin-clavulanic acid) may result from the high level of hydrolysis of the beta-lactam rather than to the clavulanic acid resistance properties of PSE-1 in these clonally related S . typhimurium isolates.

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