Salmonella

Immunopharmacol Immunotoxicol, 2000 Aug, 22(3), 451 - 64
Evaluation of the natural immunity in pups inoculated with a modified-live canine parvovirus type 2b (CPV-2b) strain; Pratelli A et al.; Three pups 2-4 months old were vaccinated subcutaneously with the modified live canine parvovirus, CPV-2b/29-97 strain . During an observation period of two weeks pups remained clinically health, exhibiting a vigorous post-vaccinal active serological response (haemoagglutinating inhibiting antibody titers for CPV-2 ranging from 1:2560 to 1:5120 at 21 days post inoculation) . Phagocytosis and killing of Candida albicans exerted by polymorphonuclear cells and monocytes did not undergo significant modifications 3-6 days post vaccination up to 30 days . Antibacterial activity mediated by peripheral blood lymphocytes (Salmonella typhi was used as a target) was slightly, but not significantly decreased 3 days post vaccination . Conclusively, in pups the CPV type 2b vaccine seems to be safe as far as natural immune responses are concerned, while its immunogenicity is preserved.

New Microbiol, 2000 Jan, 23(1), 11 - 20
Application of PFGE performed with XbaI to an epidemiological and phylogenetic study of Salmonella serotype typhimurium . Relations between genetic types and phage types; Guerra B et al.; PFGE performed with XbaI was evaluated and applied as a typing method in a series of 68 Salmonella serotype Typhimurium strains collected in a Spanish region throughout 1984-1994, and four reference strains . Using bands > 100 kb as a separation criterion, 26 pulsed-field profiles (PFPs) were defined, with a discrimination index of 0.87 . The XbaI-profiles were grouped into three clusters and two additional branches in a dendrogram of similarity (significance level = 0.7) . Strains belonging to PFP-X1 and PFP-X2 predominated (26.4% and 23.6%, respectively) and fell into the major cluster . The series had been previously analysed by phage typing and a three-way ribotyping procedure, and a certain degree of relation among the three methods was revealed, PFGE being the most discriminatory . Combining data from the three methods a further differentiation into 46 clonal lines was obtained, and four lines, at least, could be considered as endemic in the region under study . This procedure proved to be a powerful epidemiological tool for characterization of Typhimurium and in the investigation of outbreaks.

Mutat Res, 2000 Aug 21, 469(1), 41 - 50
Chemical and mutagenic properties of asphalt fume condensates generated under laboratory and field conditions; Reinke G et al.; Exposure to asphalt fumes is widely recognized as a potential occupational health concern for paving and roofing workers . Two studies suggest that asphalt fumes generated in the laboratory are carcinogenic to mice . In this study, asphalt fume condensate (AFC) was collected from the head space of an operating hot mix asphalt storage tank and from a laboratory fume-generating apparatus operating at approximately 149 degrees C and 316 degrees C . Salmonella assays for mutagenesis, in vitro chromosomal aberration assays using Chinese hamster ovary (CHO) cells, chemical analyses, and simulated distillations were performed using gas chromatography to characterize the toxicological and chemical properties of AFCs generated by these two methods . The 316 degrees C lab AFC sample was more mutagenic in the Salmonella assay than the 149 degrees C lab AFC sample, with mutagenicity indices (MIs) of 8.3 and 5.3, respectively . AFCs collected from the storage tank were not mutagenic . Chromosomal aberration assays of all AFCs were negative . Chemical analyses and simulated distillations showed substantial differences in the chemical composition of the AFC samples . The 316 degrees C lab AFC sample contained more higher-boiling-point (three- and four-ring) polycyclic aromatic sulfur heterocycle compounds than the 149 degrees C lab AFC sample, and both lab AFC samples contained 5 to 100 times more of these compounds than AFC samples collected from the asphalt storage tank . These results are consistent with other data reported in the scientific literature describing the carcinogenicity of higher-boiling-point sulfur heterocycle compounds . In contrast to other recent studies, the results of this study indicate that the chemical composition and toxicological properties of laboratory-generated asphalt fumes are not representative of those properties of fumes to which workers and the public might be exposed.

Vet Microbiol, 2000 Sep 25, 76(2), 185 - 92
Orally administered attenuated Salmonella enteritidis reduces chicken cecal carriage of virulent Salmonella challenge organisms; Cerquetti MC et al.; Chickens were immunized orally with 10(9)cfu of the temperature-sensitive (T(s)) mutant E/1/3 of Salmonella enteritidis at 1, 2, 3 and 7 days of age . The animals were challenged with wild-type strains of Salmonella of different serotypes 7 or 14 days following immunization . Chickens receiving multiple oral doses of the vaccine strain showed no signs of disease . Immunized animals shed the vaccine strain for at least 2 weeks after the last inoculation; on the other hand, colonization by the attenuated mutant of internal organs such as spleen and liver was limited . Early exposure of the immunized animals to the virulent bacteria resulted in a reduced cecal colonization by the pathogen . Visceral invasion by the wild-type strain of S . enteritidis or S . gallinarum was drastically diminished in birds challenged 14 days after immunization . Significant differences in the number of these Salmonella were found in the cecal contents, spleen and liver of immunized birds compared with the control animals . In addition, cecal colonization by the virulent strain was reduced in birds challenged with S . typhimurium . These results demonstrate that immunization of newly hatched chickens with live attenuated T(s) mutant E/1/3 of S . enteritidis is safe and reduces Salmonella shedding.

Vet Microbiol, 2000 Sep 25, 76(2), 143 - 51
Prevalence of Salmonella in beef feeder steers as determined by bacterial culture and ELISA serology; Galland JC et al.; Results are presented for monitoring Salmonella infection by bacteriological culture and immune response (enzyme linked immunosorbent assay (ELISA) and haptoglobin) testing of samples collected from beef cattle at a single feedyard sampled over time . A total of 120 beef steers were examined on entry to the feedyard and at days 30, 60, and at time of slaughter (120-150 days) . Isolations of Salmonella decreased over time from 40% of the steers sampled at day 0 to 0% at slaughter, whereas serological results varied by serogroup . Seropositivity increased for Salmonella group B up to day 60, and subsequently decreased to about half of the 60-day positivity rate at the time of slaughter . No significant changes in seropositivity were detected during the course of the study for the four other Salmonella serogroups (C1, C3, D1, and E1) . Haptoglobin measurements were not a good indicator of Salmonella infection status . Sequential Salmonella testing either by culture, ELISA, or both could be used to monitor pathogen control practices.

J Appl Microbiol, 2000 Jul, 89(1), 130 - 6
16S to 23S rRNA spacer fragment length polymorphism of Salmonella enterica at subspecies and serotype levels; Christensen H et al.; The variation in the lengths of the internal transcribed spacer (ITS) between 16S and 23S rRNA genes of 101 strains representing 58 serotypes of Salmonella enterica (used for Salm . choleraesuis) subsp . enterica (I), salamae (II), arizonae (IIIa), diarizonae (IIIb), houtenae (IV) and indica (VI) was used for typing by PCR amplification . Ten fragment lengths were observed by denaturing polyacrylamide gel electrophoresis on an automatic DNA sequencer resulting in 21 unique fragment patterns . Ten out of the 58 serotypes showed specific patterns but 48 serotypes were not fully differentiated . More than one ITS pattern was observed in seven serotypes . Five of the 21 fragment patterns contained representatives of more than one subspecies . Under non-denaturing electrophoresis conditions, serotype specificity was obtained but precise ITS fragment length determination was not possible . DNA sequence comparison between ITSs of individual rrn operons is needed to further interpret ITS diversity within Salm . enterica at serotype and subspecies levels.

J Food Prot, 2000 Aug, 63(8), 1144 - 53
Microbiological safety of mayonnaise, salad dressings, and sauces produced in the United States: a review; Smittle RB; The literature on the death and survival of foodborne pathogens in commercial mayonnaise, dressing, and sauces was reviewed and statistically analyzed with emphasis on Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes . The absence of reports of foodborne illness associated directly with the consumption of commercially prepared acidic dressings and sauces is evidence of their safety . Salmonella, E . coli O157:H7, E . coli, L . monocytogenes, Staphylococcus aureus, and Yersinia enterocolitica die when inoculated into mayonnaise and dressings . Historically, mayonnaise and dressings have been exempt from the acidified food regulations and have justly deserved this status due primarily to the toxic effect of acetic and to a lesser extent lactic and citric acids . These organic acids are inimical to pathogenic bacteria and are effective natural preservatives with acetic being the most effective in killing pathogenic bacteria at the pH values encountered in these products . Statistical analysis on data reported in the literature shows that the most important and significant factor in destroying pathogenic bacteria is pH as adjusted with acetic acid followed by the concentration of acetic acid in the water phase . The reported highest manufacturing target pH for dressings and sauces is 4.4, which is below the 4.75 pKa of acetic acid and below the reported inhibitory pH of 4.5 for foodborne pathogens in the presence of acetic acid . The overall conclusion is that these products are very safe . They should remain exempt from the acidified food regulations providing adequate research has been done to validate their safety, and the predominant acid is acetic and reasonable manufacturing precautions are taken.

J Food Prot, 2000 Aug, 63(8), 1113 - 6
Recalls of foods and cosmetics due to microbial contamination reported to the U.S . Food and Drug Administration; Wong S et al.; In the U.S., food product recalls serve as an important intervention in stemming the consumption of food products contaminated with infectious disease agents . We summarize the number and nature of foods and cosmetics recalled as a result of microbial contamination reported to the U.S . Food and Drug Administration (FDA) for the period 1 October 1993 through 30 September 1998 . During this period, microbial contamination of food and cosmetic products was the leading cause for recalls, accounting for a total of 1,370 recalls (36% of all products recalled) . Listeria monocytogenes accounted for the greatest number of food products recalled because of microbial contamination, whereas Pseudomonas aeruginosa was the most common microbe associated with recalls of cosmetic products . Dairy products, followed by seafood and pastry items, were the types of products most often associated with recalls due to microbial contamination . The FDA was the entity most often responsible for detecting microbial contamination of foods and cosmetics (33% of all such recalls), followed by state regulatory agencies (24%), and manufacturers/retailers (21%) . Nineteen percent of recalls were associated with at least one reported case of illness . Salmonella was the pathogen most often implicated in reports of illness associated with these recalled products.

J Food Prot, 2000 Aug, 63(8), 1053 - 7
Survival of Yersinia enterocolitica and mesophilic aerobic bacteria on eggshell after washing with hypochlorite and organic acid solutions; Favier GI et al.; Populations of Yersinia enterocolitica 0:9 and mesophilic aerobic bacteria on the shell of fresh chicken eggs were assessed prior and after washing with 0.75%, 1%, and 3% acetic and lactic acids, 50, 100, and 200 mg/liter (ppm) of chlorine, and water . Highest reductions of mesophilic aerobic bacterial populations (normal flora) on trypticase soy agar were 1.28 and 2.15 log10 cycles with 100 and 200 mg/liter of chlorine, 0.28 and 0.36 log10 cycles with 1% and 3% acetic acid, and 0.70 and 0.71 log10 cycles with 1% and 3% lactic acid, respectively, as compared to the control group . No Salmonella or Yersinia were detected among the natural flora of the eggs . On Y . enterocolitica O:9-inoculated eggs, reductions of 2.66, 2.77, and 2.92 log10 cycles by 50, 100, and 200 mg/liter of chlorine, of 2.47, 2.48, and 2.49 log10 cycles by 0.75%, 1%, and 3% of acetic acid, and of 2.48 and 2.72 log10 cycles with 1% and 3% of lactic acid, respectively, were observed with respect to the control . Organic acids at 3% caused detachment of the surface cuticle of the eggshell . Y . enterocolitica was more sensitive to the wash treatments than the natural microflora . The absence of potentially pathogenic Y . enterocolitica, observed for other fresh foods, should be a norm for fresh eggs sold in retail stores.

J Vet Med Sci, 2000 Jul, 62(7), 789 - 91
Salmonella contamination in commercial layer feed in Japan; Shirota K et al.; A total of 4,418 samples of commercial layer feeds obtained in 1998 were investigated for the presence of salmonellae . A total of 146 strains of salmonellae which consisted of 32 serovars, including 20 strains of Salmonella Enteritidis, were isolated from 143 feed samples.

J Vet Med Sci, 2000 Jul, 62(7), 767 - 9
Salmonella virchow infection in an infant transmitted by household dogs; Sato Y et al.; A 4-month-old male infant manifested diarrhea and Salmonella Virchow was isolated from his stool . The pathogen was repeatedly isolated from the infant over one month despite three regimens of treatment with antibiotics, to which the isolate was sensitive . Three household dogs were kept in his home and S . Virchow was isolated from two of them . The infant was admitted to hospital and was treated with antibiotic, then the pathogen was finally eliminated . Antibiotic sensitivity pattern and PFGE pattern produced by restriction enzyme Xba I of the isolate from the infant was completely similar to those of the isolates from the dogs . The above findings indicated that the present S . Virchow infection in the infant was transmitted by the household dogs.

East Afr Med J, 2000 Jan, 77(1), 23 - 6
Chronic osteomyelitis in patients with sickle cell disease; Nwadiaro HC et al.; OBJECTIVE: To determine the baseline pattern and audit management modalities of chronic osteomyelitis in patients with sickle cell disease . DESIGN: A retrospective study . SETTING: Jos University Teaching Hospital, Jos, Nigeria from August 1993 to July 1997 . PATIENTS: Twenty four patients with concomitant chronic sickle cell disease . INTERVENTIONS: Fifteen patients had operations; eleven had sequestrectomy and curettage while four had incision and drainage . Eight patients were treated with antibiotics alone and one patient refused surgery . MAIN OUTCOME MEASURES: The demographic data of patients, aetiological agents, culture and sensitivity patterns, aetiopathogenesis, treatment modalities and outcome were analysed . RESULTS: Twenty four (36.9%) out of 65 patients who had chronic osteomyelitis also had sickle cell disease . Male:female ratio was 1.2:1 . The peak age incidence (37.5%) was in the first decade of life . Seventy five per cent of infections were haematogenous . The most frequently isolated organism was Staphylococcus aureus (58.8%) while the rest were Gram negative organisms . There was no case of Salmonella osteomyelitis . The most sensitive antibiotics were gentamicin and the third generation cephalosporins . Twelve patients (50%) had good results while eight (33.3%) were still undergoing treatment . Complications recorded were persistent discharging sinuses in two cases, recurrence of symptoms in one and pathological fracture with non-union in one patient . CONCLUSION: Though the incidence of Gram negative organisms in causation of chronic osteomyelitis in patients who have sickle cell disease is high (41.2%), Salmonella osteomyelitis may be related to endemicity of the organism in a given locality.

Microbiol Immunol, 2000, 44(6), 473 - 9
Blockade of Salmonella enteritidis passage across the basolateral barriers of human intestinal epithelial cells by specific antibody; Sugita-Konishi Y et al.; Antibodies specific to Salmonella enteritidis (S.E.) were obtained from immunized egg yolk, and their protective effects against S.E . were studied by using monolayer-cultured human intestinal epithelial cells, Caco-2 and T84 . The Salmonella adherence and entry to the cells were partially inhibited by the antibodies . The antibodies inhibited the decrease in transepithelial electrical resistance (TEER) of the intestinal epithelial monolayers and IL-8 secretion of the cells induced by S.E . invasion . Also, the antibodies blocked the penetration of bacteria through the cell layer although they did not inhibit the growth of bacteria in the cells . Confocal microscopic photographs revealed the bacteria in the infected monolayer cells were bound to antibodies . These results indicate that anti-S.E . antibodies may protect the cells from destruction induced by S.E . invasion in intestinal epithelial cells in addition to the partial inhibition of adhesion and invasion of S.E . at the cell surface . Passive antibodies against invasive bacteria would be useful to prevent the migration of S.E . to blood not only at the cell surface but also inside of intestinal epithelial cells.

Ned Tijdschr Geneeskd, 2000 Jul 29, 144(31), 1480 - 4
{Clinical thinking and decision making in practice . A patient with persistent fever}; Koopmans RP et al.; A 20-year old man was admitted to hospital with fever and malaise after travel to India . He was soon found to have typhoid fever, caused by a multi-drug resistant Salmonella typhi . According to in-vitro resistance testing he was treated with cefotaxim, but fever and shivering were still present after 7 days of cefotaxim, with liver enzyme disturbances . The physicians caring for him started an extensive search for possible complications of typhoid fever, and they thought of the possibility of an alternative disease to explain the fever . When cefotaxim was stopped all symptoms and signs disappeared . During every medication, drug fever is a possibility . This diagnosis can only be supported by discontinuing the use and if necessary, restarting it (dechallenge and rechallenge).

J Bacteriol, 2000 Sep, 182(17), 4906 - 14
Domain structure of Salmonella FlhB, a flagellar export component responsible for substrate specificity switching; Minamino T et al.; We have investigated the properties of the cytoplasmic domain (FlhB(C)) of the 383-amino-acid Salmonella membrane protein FlhB, a component of the type III flagellar export apparatus . FlhB, along with the hook-length control protein FliK, mediates the switching of export specificity from rod- and hook-type substrates to filament-type substrates during flagellar morphogenesis . Wild-type FlhB(C) was unstable (half-life, ca . 5 min), being specifically cleaved at Pro-270 into two polypeptides, FlhB(CN) and FlhB(CC), which retained the ability to interact with each other after cleavage . Full-length wild-type FlhB was also subject to cleavage . Coproduction of the cleavage products, FlhB(delta CC) (i.e., the N-terminal transmembrane domain FlhB(TM) plus FlhB(CN)) and FlhB(CC), resulted in restoration of both motility and flagellar protein export to an flhB mutant host, indicating that the two polypeptides were capable of productive association . Mutant FlhB proteins that can undergo switching of substrate specificity even in the absence of FliK were much more resistant to cleavage (half-lives, 20 to 60 min) . The cleavage products of wild-type FlhB(C), existing as a FlhB(CN)-FlhB(CC) complex on an affinity blot membrane, bound the rod- and hook-type substrate FlgD more strongly than the filament-type substrate FliC . In contrast, the intact form of FlhB(C) (mutant or wild type) or the FlhB(CC) polypeptide alone bound FlgD and FliC to about the same extent . FlhB(CN) by itself did not bind substrates appreciably . We propose that FlhB(C) has two substrate specificity states and that a conformational change, mediated by the interaction between FlhB(CN) and FlhB(CC), is responsible for the specificity switching process . FliK itself is an export substrate; its binding properties for FlhB(C) resemble those of FlgD and do not provide any evidence for a physical interaction beyond that of the export process.

Int J Syst Evol Microbiol, 2000 Jul, 50 Pt 4, 1693 - 4
Arguments against the replacement of type species of the genus Salmonella from Salmonella choleraesuis to 'Salmonella enterica' and the creation of the term 'neotype species', and for conservation of Salmonella choleraesuis; Yabuuchi E et al.; The proposals of Le Minor and Popoff in 1987 and again of Euzeby in 1999 on the type species of the genus Salmonella are in violation of Rule 20a of the Bacteriological Code (1990 Revision) and should be rejected . The introduction of the term 'neotype species' should be rejected . The specific epithet choleraesuis in the binary combination Salmonella choleraesuis should be conserved . The serovar name Choleraesuis should be changed to Hogcholera.

Indian J Med Res, 2000 Mar, 111, 75 - 6
Occurrence of Salmonella typhi infection in Rourkela, Orissa; Bhattacharya SS et al.; Between January 1996 and December 1998, the isolation rate of Salmonella typhi in Rourkela was found to be on a steady rise . Of the 7866 samples (blood and bone marrow) tested, 988 were found positive for S . typhi giving an overall per cent positivity of 12.56 . Enteric fever was found to occur almost throughout the year with a peak from early winter up to the end of summer . In this study, chloramphenicol was found to have an average sensitivity of 87.46 per cent . Ceftriaxone showed 100 per cent sensitivity.

Turk J Pediatr, 2000 Apr-Jun, 42(2), 151 - 4
Salmonella septic arthritis in a patient with acute idiopathic thrombocytopenic purpura treated with steroid; Kanra G et al.; Salmonella has three clinical presentations: self-limiting gastroenteritis, a systemic syndrome (enteric or typhoid fever), and bacteremia with focal infection . Hematogenous infections can cause focal lesions, but unusual manifestations occur more often when predisposing factors such as T cell defect, hemolytic disorders (sickle cell disease, malaria) or trauma are present . Salmonella tend to invade bones and joints . There is no mention of acute idiopathic (immune) thrombocytopenic purpura as a predisposing factor for salmonella septic arthritis; however there are reports about the importance of platelets for the immune response . Here we present a case of Salmonella enteritidis septic arthritis following acute idiopathic (immune) thrombocytopenic purpura in a 15-year-old female patient who has been on steroid therapy for the last two weeks.

Chem Biol Interact, 2000 Jul 3, 127(2), 163 - 80
Genotoxic effects of allyl isothiocyanate (AITC) and phenethyl isothiocyanate (PEITC); Kassie F et al.; Two isothiocyanates (ITCs) commonly found in human diet, allyl isothiocyanate (AITC) and phenethyl isothiocyanate (PEITC), were tested for genotoxic effects in a battery of assays: Salmonella/microsome assay with TA 98 and TA 100, differential DNA repair assay with E . coli and micronucleus (MN) induction assay with human derived Hep G2 cells . Albeit to a different degree, both ITCs induced genotoxic effects in all test systems . AITC was more genotoxic in bacterial test systems than in Hep G2 cells; in contrast, the effect of PEITC was stronger in Hep G2 cells . In in vivo assays with E . coli indicators in which mice were exposed to relatively high doses of the compounds (90 and 270 mg/kg), AITC induced moderate but significant effects; PEITC failed to induce significant effects in any of the organs . To find out the reason for the weak genotoxicity of AITC and PEITC under in vivo test conditions, we exposed E . coli indicator cells to the test substances in the absence or presence of rat liver homogenate (with and without cofactors), bovine serum albumin (BSA) and human saliva . All of them markedly attenuated the genotoxicity of AITC and PEITC, implying that the test substances are detoxified by direct non-enzymatic binding to proteins . Additional experiments carried out on the mechanistic aspects of AITC and PEITC-induced genotoxicity showed that the compounds induce the formation of thiobarbituric acid reactive substances (TBARS) in Hep G2 cells . Furthermore, in in vitro assays with E . coli, radical scavengers reduced the differential DNA damage induced by AITC and PEITC . The latter two findings give a clue that reactive oxygen species might be involved in the genotoxic effect of the ITCs . Although ITCs have been repeatedly advocated as very promising anticancer agents, the data presented here indicate that the compounds are genotoxic, and probably carcinogenic, in their own right.

Rev Sci Tech, 2000 Aug, 19(2), 405 - 24
Fowl typhoid and pullorum disease; Shivaprasad HL; Fowl typhoid (FT) and pullorum disease (PD) are septicaemic diseases, primarily of chickens and turkeys, caused by Gram negative bacteria, Salmonella Gallinarum and S . Pullorum, respectively . Clinical signs in chicks and poults include anorexia, diarrhoea, dehydration, weakness and high mortality . In mature fowl, FT and PD are manifested by decreased egg production, fertility, hatchability and anorexia, and increased mortality . Gross and microscopic lesions due to FT and PD in chicks and poults include hepatitis, splenitis, typhlitis, omphalitis, myocarditis, ventriculitis, pneumonia, synovitis, peritonitis and ophthalmitis . In mature fowl, lesions include oophoritis, salpingitis, orchitis, peritonitis and perihepatitis . Transovarian infection resulting in infection of the egg and subsequently the chick or poult is one of the most important modes of transmission of these two diseases . Salmonella Gallinarum and S . Pullorum can be isolated by use of selective and non-selective media . Salmonella Pullorum produces rapid decarboxylation of ornithine whereas S . Gallinarum does not, an important biochemical difference between the two bacteria . Both FT and PD can be detected serologically by use of a macroscopic tube agglutination test, rapid serum test, stained antigen whole blood test or microagglutination test . Both diseases can be controlled and eradicated by use of serological testing and elimination of positive birds . Vaccines may be used to control the disease and antibiotics for the treatment of FT and PD . Although FT and PD are widely distributed throughout the world, the diseases have been eradicated from commercial poultry in developed countries such as the United States of America, Canada and most countries of Western Europe . Both S . Gallinarum and S . Pullorum are highly adapted to the host species, and therefore are of little public health significance.

Rev Sci Tech, 2000 Aug, 19(2), 351 - 75
The paratyphoid salmonellae; Barrow PA; The paratyphoid Salmonella bacteria, comprising more than 2,000 serovars or serotypes, are a major problem to the poultry industry . This is largely the result of entry of the bacteria into the human food chain . Human infection takes the form of a gastroenteritis, which in highly susceptible individuals can result in death . Some strains of certain serotypes have the capacity to produce morbidity and mortality in very young chickens . In adult birds, some serovars become localised in the reproductive tract with concomitant vertical transmission . The association between S . Enteritidis and table eggs has produced a great deal of publicity and concern with resulting national and international attempts at controlling the major serotypes, S . Typhimurium and S . Enteritidis, at the breeder and layer level . Control is possible through rigorous hygiene and management procedures, but is not always economically viable . As a result, control by serological and bacteriological testing and slaughter may also not be feasible . Antibiotics have been used to reduce carriage but can cause problems of resistance and increased susceptibility . The use of growth promoting antibiotics can also increase susceptibility to infection . Other means of increasing the resistance of poultry to infection are therefore being sought . These include the use of intestinal flora preparations for competitive exclusion of Salmonella from newly hatched chicks . Killed and live vaccines are used, both with some success . However, the safety of some live vaccines is still uncertain.

J Med Microbiol, 2000 Aug, 49(8), 691 - 6
Adhesion of Salmonella enterica var Enteritidis strains lacking fimbriae and flagella to rat ileal explants cultured at the air interface or submerged in tissue culture medium; Robertson JM et al.; Rat ileal air interface and submerged explant models were developed and used to compare the adhesion of Salmonella enterica var Enteritidis wild-type strains with that of their isogenic single and multiple deletion mutants . The modified strains studied were defective for fimbriae, flagella, motility or chemotaxis and binding was assessed on tissues with and without an intact mucus layer . A multiple afimbriate/aflagellate (fim-/fla-) strain, a fimbriate but aflagellate (fla-) strain and a fimbriate/flagellate but non-motile (mot-) strain bound significantly less extensively to the explants than the corresponding wild-type strains . With the submerged explant model this difference was evident in tissues with or without a mucus layer, whereas in the air interface model it was observed only in tissues with an intact mucus layer . A smooth swimming chemotaxis-defective (che-) strain and single or multiple afimbriate strains bound to explants as well as their corresponding wild-type strain . This suggests that under the present experimental conditions fimbriae were not essential for attachment of S . enterica var Enteritidis to rat ileal explants . However, the possession of active flagella did appear to be an important factor in enabling salmonellae to penetrate the gastrointestinal mucus layer and attach specifically to epithelial cells.

Rev Latinoam Microbiol, 1999 Jul-Sep, 41(3), 121 - 6
{Antimicrobial resistance among species of Salmonella, Shigella, Escherichia, and aeromonas isolated from children with diarrhea in 7 Argentinian centers}; Binsztein N et al.; The increasing levels of resistance of enteropathogenic bacteria against antimicrobial agents present geographic variations . We have analysed the antimicrobial susceptibility of isolates obtained from 4,364 children under 5 years of age with acute diarrhea, in 7 cities of Argentina . Diarrheagenic E . coli exhibited 74.5% of resistance against ampicillin, 64.2% against sulfametoxazole-trimethoprim, and Shigella spp., 62% and 75.6% respectively . Salmonella sp . showed 35%, 14%, 41.8%, 65.4%, 14.5%, and 13.6% of resistance against ampicillin, chloranfenicol, sulfametoxazole-trimetoprim, sulfadiazin, gentamycin, and fosfomycin respectively . These values are higher than the ones observed in developed countries . Aeromonas showed significantly lower resistance percentage . Important differences in our country were observed, consequently, local trials should be carried out in order to apply corrective measures.

Mol Microbiol, 2000 Jul, 37(2), 300 - 15
The cis requirements for transcriptional activation by HilA, a virulence determinant encoded on SPI-1; Lostroh CP et al.; In several models of pathogenesis, Salmonella requires genes encoded on Salmonella pathogenicity island 1 (SPI-1) for virulence . In Salmonella enterica serovar Typhimurium (S . typhimurium), most SPI-1 genes are arranged in operons and are co-ordinately regulated in response to environmental signals via the SPI-1-encoded protein HilA . In order to understand how HilA controls the transcription of SPI-1 genes, we have analysed the invF and prgH promoters . We have reconstituted HilA-dependent activation of both promoters in Escherichia coli by supplying hilA on a plasmid, strongly suggesting that HilA acts directly on the promoters . By analysing the HilA-dependent activity of deletions and mutations in PinvF, we identified cis elements necessary for HilA-dependent activation . Through biochemical studies, we have defined a probable HilA-binding sequence in the invF promoter . This 'HilA box' is intact in the minimal promoter identified through deletion analysis, and it is disrupted in one class of PinvF mutants that has reduced activation by HilA . The prgH promoter also contains a HilA box in the same position relative to the +1 of transcription . This work is the first to connect HilA-dependent environmental regulation with a specific sequence in a SPI-1 virulence gene promoter.

Eur J Biochem, 2000 Aug, 267(16), 5023 - 31
Hadrurin, a new antimicrobial peptide from the venom of the scorpion Hadrurus aztecus; Torres-Larios A et al.; A new antimicrobial peptide, hadrurin, was isolated from the venom of the Mexican scorpion Hadrurus aztecus, by gel filtration on a Sephadex G-50 column, followed by high performance liquid chromatography . It is a basic peptide composed of 41 amino-acid residues with a molecular mass of 4436 Da, and contains no cysteines . A model of the three-dimensional folding of hadrurin is compatible with that of an amphipatic molecule with two alpha-helical segments . Hadrurin demonstrates antimicrobial activity at low micromolar concentration, inhibiting the growth of bacteria such as: Salmonella thyphi, Klebsiella pneumoniae, Enterococcus cloacae, Pseudomonas aeruginosa, Escherichia coli and Serratia marscences . It also shows cytolytic activity when tested in human erythrocytes . Hadrurin and two analogs (C-terminal amidated, and all D-enantiomer) were chemically synthesized . They were used to study the possible molecular mechanism of action by testing their ability to dissipate the diffusion potential of liposomes of different compositions . The results obtained indicate that there are no specific receptor molecules for the action of hadrurin, and the most probable mechanism is through a membrane destabilization activity . It is surmised that hadrurin is used by the scorpion as both an attack and defense element against its prey and putative invasive microorganisms . It is a unique peptide among all known antimicrobial peptides described, only partially similar to the N-terminal segment of gaegurin 4 and brevinin 2e, isolated from frog skin . It would certainly be a model molecule for studying new antibiotic activities and peptide-lipid interactions.

FEMS Microbiol Lett, 2000 Aug 15, 189(2), 285 - 91
Partial characterization of a genomic island associated with the multidrug resistance region of Salmonella enterica Typhymurium DT104; Boyd DA et al.; This study describes the identification of the insertion site and partial characterization of a 43-kb region harboring the genes associated with the penta-resistant phenotype of a Canadian isolate of Salmonella enterica Typhymurium DT104 labelled 96-5227 . The 43-kb fragment, here referred to as Salmonella genomic island I (SgiI), was found in the genome of S . enterica Typhymurium between the thdf and a prophage CP-4-like integrase (int2) gene and is flanked by an imperfect 18-bp direct repeat . A region downstream of sulI in the right end of SgiI contained four open reading frames which includes an IS6100 element, and a 2-kb region from the left end contained two open reading frames which showed homology to an integrase and an excisionase . Furthermore, a 1.9-kb retron sequence located between int2 and yidY was identified which may be unique to the S . enterica Typhymurium genome . The int-retron sequence is flanked by a 27-bp imperfect direct repeat.

Z Naturforsch {C}, 2000 May-Jun, 55(5-6), 489 - 93
Prevalence of multi-drug resistant Salmonella typhi among clinically diagnosed typhoid fever patients in Lagos, Nigeria; Akinyemi KO et al.; A total of 635 clinically diagnosed typhoid fever patients were bled from three different health institutions in the metropolis of Lagos, Nigeria over a period of 15 months, May 1997 to July 1998 . Out of the total blood cultured, 101 (15.9%) isolates of Salmonella species were isolated of which 68 (67.3%) were S . typhi, 17 (16.8%) and 16 (15.8%) were S . paratyphi A . and S . arizonae respectively . The overall isolation rate of S . typhi among patients is 10.7%, with most isolates 45.9% found among the severely-ill young adults, age group 16-30 years . All isolates were subjected to anti-microbial susceptibility testing using 12 different antibiotics: chloramphenicol, ampicillin, cotrimoxazole, gentamicin, colistin sulfate, nalidixic acid, nitrofurantoin, cefotaxime, tetracycline, streptomycin, ofloxacin and ciprofloxacin . All the S . typhi and S . paratyphi A isolates showed resistance to two or more of the 10 of 12 antibiotics tested particularly the 3-first-line antibiotics commonly used (chloramphenicol, ampicillin and cotrimoxazole) in the treatment of typhoid fever in Nigeria . No isolate showed resistance to ofloxacin and ciprofloxacin, however, nalidixic acid and gentamicin showed a moderate and appreciable inhibition to most of our isolates.

Southeast Asian J Trop Med Public Health, 1999 Dec, 30(4), 776 - 8
Incidence of new Salmonella serovar (S . ratchaburi) in Thailand; Bangtrakulnonth A et al.; Eighteen strains of Salmonella group E from stool samples were confirmed as Salmonella new serovar . 3, 10 : Z35 : 1, 6 by Centre International des Salmonella, Institut Pasteur, Paris, WHO Collaborating Center for Salmonella, Atlanta, USA and Salmonella-Zentrale Hygienischen Institut, Hamburg, Germany . The name of this new serovar was proposed as S . ratchaburi according to the place of its first isolation in Ratchaburi province . The new serovar of Salmonella was sensitive to many antimicrobial agents except streptomycin and erythromycin.

Southeast Asian J Trop Med Public Health, 1999 Dec, 30(4), 764 - 9
Comparison of the efficacy of ceftibuten and norfloxacin in the treatment of acute gastrointestinal infection in children; Moolasart P et al.; A prospective randomized study was conducted at an infectious disease hospital in Thailand . Ceftibuten was compared with norfloxacin, both given orally for five days for treatment of acute gastroenteritis in children . One hundred and seventy cases were included in the study . Eighty-eight cases were treated with ceftibuten and eighty-two cases with norfloxacin . The baseline characteristics of the patients in both treatment groups were similar . The results showed that mean durations of diarrhea in the ceftibuten and norfloxacin groups were 2.48 days and 2.29 days, respectively, but there was no statistically significant difference between the two groups (p > 0.05) . There were Salmonella spp and Shigella spp isolated in both treatment groups and all were susceptible to both antibiotics . The mean durations of Salmonella diarrhea in the ceftibuten and norfloxacin groups were 2.7 and 2.2 days, respectively, while those of Shigella diarrhea were 2.3 days and 2.0 days, respectively . There were no statistically significant differences in either comparison (p > 0.05) . Neither complications nor clinical relapses were observed after both antibiotics' treatment.

Acta Paediatr Taiwan, 1999 Nov-Dec, 40(6), 430 - 3
Characterization of group D1 non-typhoid Salmonella isolates by serotyping and pulsed field gel electrophoresis; Li WC et al.; Non-typhoid salmonella infection is not uncommon in immunocompetent patients in Taiwan . Bacterial factors may play an important role in the pathogenesis of such infections . In a previous study, Salmonella group D1 was found to have the tendency to cause bacteremia with a higher frequency than other serotypes . In the present study, we prospectively collected 94 Salmonella group D1 isolates for serotyping and molecular typing . Salmonella panama and Salmonella dublin seemed more invasive than other serotypes . Pulsed field gel electrophoresis was also done to characterize of Salmonella enteritidis and Salmonella dublin . PFGE type "a" of Salmonella dublin appeared to be more invasive than the other two PFGE types . All six Salmonella dublin isolates were Vi antigen negative . Further study using a larger number of isolates is needed to identify the tendency to invade blood stream of Salmonella dublin and Salmonella panama.

Berl Munch Tierarztl Wochenschr, 2000 Jun, 113(6), 246 - 52
{A new live Salmonella enteritidis vaccine for chickens--experimental evidence of its safety and efficacy}; Springer S et al.; Within the works for the registration of a new live Salmonella Enteritidis vaccine for layers, safety and efficacy of the vaccine strain were tested by experimental studies . After oral administration of the single and the tenfold dose, no incompatibility reactions were seen in day-old chicks . The laying performance and the egg weight were not affected by the vaccination of the chickens during the laying period . There was only a limited period in which the excretion of the vaccine strain and its persistency in organs were seen . Even after the threefold oral vaccination the vaccine strain could not be isolated from eggs and internal organs of slaughtered chickens . Moreover, a high safety for non-target animals (cattle, pigs) could be established . Studies with BALB/c mice proved that a cell-mediated immunity and the development of complement-fixing antibodies is induced by the vaccine . Efficacy studies in target animals were carried out by a proved dependable oral challenge system that reproduces a latent infection with marked S . Enteritidis strains and by means of the seeder-bird method . The test results demonstrate that the vaccination is capable to avert or to reduce an infection significantly.

Berl Munch Tierarztl Wochenschr, 2000 Jun, 113(6), 225 - 33
{Results of the German investigation in the EU Project "Salmonella in Pork (Salinpork)"--2 . Investigations in a slaughterhouse}; von Altrock A et al.; In 1997 bacteriological examinations for the distribution of Salmonella in slaughterhouses were carried out in Germany within the framework of an international study "Salmonella in Pork (Salinpork)" . During 6 days, 1,200 swab and water samples from slaughtered pigs and the environment were taken . 4.4% of the samples (n = 53) were Salmonella positive . S . typhimurium was isolated mainly (69.8%; n = 37), and 6 phagetypes were differentiated . In addition, S . derby and S . panama could be demonstrated . The resistance pattern of the different isolated S . typhimurium-phagetypes are presented . The phagetype DT 104 was multiresistant to ampicillin, spectinomycin, streptomycin, sulphonamide and tetracycline . In comparison with the serological prevalence of 7.3% of the fattening pigs in the farms (Part 1), only 1.0% of the samples taken from the surface of the carcass were Salmonella-positive . Swabs taken from the liver were in 2.7% positive and samples from the tongue gave in 5.3% of the cases Salmonella-positive results . In the examination of the environment Salmonella was demonstrated mainly from the water outlets, whereas Salmonella could not be isolated from water of the scalding tank . There was only one case (0.7%) in which Salmonella could be isolated from the hands of the personnel, and also only one swab of the polishing machine was positive (1.1%) . But 6.7% samples of the saw were Salmonella-positive . A comparison of repeated, at intervals taken samples showed that the number of Salmonella-positive samples was higher in the last examination round of the particular slaughter days . The reason is suspected in the increasing number of slaughtered pigs and supplying farms, which may increase the probability of bringing in Salmonella.

Vet Microbiol, 2000 Sep 15, 76(1), 61 - 9
Strain discrimination of a novel serotype of Salmonella from harbour porpoises (Phocoena phocoena) by molecular techniques; Crichton PB et al.; The relatedness of 41 isolates of Salmonella of a novel serotype (antigenic formula 4,12:a:-) of serogroup B, obtained from harbour porpoises (Phocoena phocoena) stranded at various sites around the coastline of Scotland, was assessed by two molecular typing methods . Ribotyping showed that these isolates belonged to seven EcoRI (E) ribotypes and 11 PstI (P) ribotypes that were, in each case, distinct but closely related . Combined ribotyping data identified 15 different E/P ribotypes, the most common of which, E1/P1, was represented by 15 isolates from 14 animals stranded on both east and west coastlines . Strain discrimination achieved by E/P ribotyping was high (D=0.84) . IS200 profiling revealed only three different fingerprints and strain discrimination by this method alone was poor (D=0.39) . When E/P ribotyping and IS200 profiling were used together, they revealed the existence of 17 different types among the 41 isolates which formed two distinct, but related, groups of Salmonella serotype 4,12:a:- . This information should prove helpful in future studies examining the mode of transmission of this novel salmonella serotype and its association with disease in harbour porpoises.

Int J Epidemiol, 2000 Aug, 29(4), 730 - 3
Have lessons been learned from the UK bovine spongiform encephalopathy (BSE) epidemic?
O'Brien M.
History is full of examples of public health, commerce and politics in conflict . In recent years attempts to protect UK egg producers, after the discovery of Salmonella enteritidis (phage type 4) in hens' eggs, strained previously good working relationships between medical and veterinary epidemiologists and ended the political career of a government minister who spoke out in defence of the public health . Against the background lessons of earlier high profile public health problems in the UK conflict should have been avoided when bovine spongiform encephalopathy (BSE) started . It might have been expected that its significance for human health could have been recognized and researched earlier . Public announcements about it could have been timely and clear . Unfortunately this was not the case and it looks as though similar mistakes are going to be repeated over genetically modified foods.

Proc Natl Acad Sci U S A, 2000 Aug 1, 97(16), 8822 - 8
Role of the cystic fibrosis transmembrane conductance regulator in innate immunity to Pseudomonas aeruginosa infections; Pier GB; Chronic Pseudomonas aeruginosa infection occurs in 75-90% of patients with cystic fibrosis (CF) . It is the foremost factor in pulmonary function decline and early mortality . A connection has been made between mutant or missing CF transmembrane conductance regulator (CFTR) in lung epithelial cell membranes and a failure in innate immunity leading to initiation of P . aeruginosa infection . Epithelial cells use CFTR as a receptor for internalization of P . aeruginosa via endocytosis and subsequent removal of bacteria from the airway . In the absence of functional CFTR, this interaction does not occur, allowing for increased bacterial loads in the lungs . Binding occurs between the outer core of the bacterial lipopolysaccharide and amino acids 108-117 in the first predicted extracellular domain of CFTR . In experimentally infected mice, inhibiting CFTR-mediated endocytosis of P . aeruginosa by inclusion in the bacterial inoculum of either free bacterial lipopolysaccharide or CFTR peptide 108-117 resulted in increased bacterial counts in the lungs . CFTR is also a receptor on gastrointestinal epithelial cells for Salmonella enterica serovar Typhi, the etiologic agent of typhoid fever . There was a significant decrease in translocation of this organism to the gastrointestinal submucosa in transgenic mice that are heterozygous carriers of a mutant DeltaF508 CFTR allele, suggesting heterozygous CFTR carriers may have increased resistance to typhoid fever . The identification of CFTR as a receptor for bacterial pathogens could underlie the biology of CF lung disease and be the basis for the heterozygote advantage for carriers of mutant alleles of CFTR.

Proc Natl Acad Sci U S A, 2000 Aug 1, 97(16), 8754 - 61
Striking a balance: modulation of the actin cytoskeleton by Salmonella; Galan JE et al.; Salmonella spp . have evolved the ability to enter into cells that are normally nonphagocytic . The internalization process is the result of a remarkable interaction between the bacteria and the host cells . Immediately on contact, Salmonella delivers a number of bacterial effector proteins into the host cell cytosol through the function of a specialized organelle termed the type III secretion system . Initially, two of the delivered proteins, SopE and SopB, stimulate the small GTP-binding proteins Cdc42 and Rac . SopE is an exchange factor for these GTPases, and SopB is an inositol polyphosphate phosphatase . Stimulation of Cdc42 and Rac leads to marked actin cytoskeleton rearrangements, which are further enhanced by SipA, a Salmonella protein also delivered into the host cell by the type III secretion system . SipA lowers the critical concentration of G-actin, stabilizes F-actin at the site of bacterial entry, and increases the bundling activity of the host-cell protein T-plastin (fimbrin) . The cellular responses stimulated by Salmonella are short-lived; therefore, immediately after bacterial entry, the cell regains its normal architecture . Remarkably, this process is mediated by SptP, another target of the type III secretion system . SptP exert its function by serving as a GTPase-activating protein for Cdc42 and Rac, turning these G proteins off after their stimulation by the bacterial effectors SopE and SopB . The balanced interaction of Salmonella with host cells constitutes a remarkable example of the sophisticated nature of a pathogen/host relationship shaped by evolution through a longstanding coexistence.

Aten Primaria, 2000 May 31, 25(9), 634 - 8
{Results of the application of a health test in a population of immigrants}; Lacalle Rodriguez-Labajo M et al.; OBJECTIVE: To describe the demographic characteristics and the results of a healthcare exam of immigrants . DESIGN: A retrospective descriptive study . SETTING: Rural doctor office of Villafranca del Castillo . Madrid . PATIENTS: All immigrants (n = 76) that came for care between May of 1996 and May of 1998 . INTERVENTIONS: History, physical exam and basic laboratory tests . RESULTS: Demographic data: 82% are women with a medium age of 33 years (SD 8.49) . Their places of origin are Central America: 70%, Philippines: 20%, Africa: 5% and South America: 3% . 97% of them work as household employees or gardeners . They have been living in Spain for an average time of 56 months . Health data: 21.1% are smokers and 17.1% low risk drinkers . 64.5% lack tetanus vaccine and 11.8% lack both tetanus and rubeola vaccines . Serologic test for HBV are negative in 68.4% . 14.5% have past infection and there are no cases of chronic or active infection . PPD is over 10 mm in 35.5%, and between 5 and 10 mm in 7.9% . Prevalence of active TBC is 0% . Stool culture is positive in 6.5% . Salmonella tiphy is identified in one case . Stool examination for ova and parasites is positive in 42.1% of the patients . Protozoos (88%) are more common than helminths (12%) . CONCLUSIONS: This study reveals a selective young and healthy immigrant group . The low presence of hepatitis B and tuberculosis infections are notable . The majority present parasites in stool samples.

J Radiol, 2000 Aug, 81(8), 899 - 901
{Infected aneurysm of abdominal aorta: early CT finding}; Sellami D et al.; Infected abdominal aortic aneurysm is an uncommon but life-threatening disease, especially in case of salmonella infection . Early CT findings should be well known in order to allow immediate diagnosis and accurate management . The authors present an early CT finding of a salmonella infected aneurysm of abdominal aorta in an HIV-infected patient . This pattern consists in a slight-enhancing focal densification of periaortic soft-tissue, while aorta remains of normal size . Within two weeks, infection progressed to the constitution of an infected aneurysm . This CT finding seems to be initial to previously described signs.

J Infect Dis, 2000 Aug, 182(2), 474 - 81 Epub 2000 Jul 18.
Natural T, gammadelta, and NK cells in mycobacterial, Salmonella, and human immunodeficiency virus infections; Jason J et al.; NK cells, gammadelta T cell antigen receptor chain-positive cells, and CD3(+)CD16/56(+) (natural T {NT}) cells are involved in innate immunity and immunoregulation; however, their role in clinical infection is not well defined . Cytofluorometric analysis was used to examine peripheral blood from bacteremic, nonbacteremic, and healthy human immunodeficiency virus (HIV)-positive and -negative persons in Malawi, Africa . Mycobacteremia was associated with a higher proportion of CD3(+)CD8(-) gammadelta cells (median, 16.6% vs . 0.7% for all other cells; P<.001), and Salmonella bacteremia was associated with a higher proportion of NT cells (4.3% vs . 2.2%; P= . 002) . HIV plasma RNA levels were weakly positively correlated with NT cells (rs=.39; P=.002), NK cells (rs=.38; P=.003), and gammadelta cells (rs=.43; P<.001) . Compared with patients who survived, patients who died had a higher percentage of NT cells (3.7% vs . 1 . 9%; P=.017) and a higher percentage of NT cells that spontaneously produced interferon-gamma (2.4% vs . 1.2%; P=.035) . The data support the clinical relevance of gammadelta and NT cells in mycobacterial, Salmonella, and HIV infections and of NT cells in mortality.

J Food Prot, 2000 Jul, 63(7), 958 - 60
Isolation of Salmonella spp . from the housefly, Musca domestica L., and the dump fly, Hydrotaea aenescens (Wiedemann) (Diptera: Muscidae), at caged-layer houses; Olsen AR et al.; Flies, especially houseflies, are widely recognized as potential reservoirs and vectors of foodborne Salmonella pathogens . In this study, flies were collected at caged-layer facilities that had produced eggs that were implicated as the food vehicle in two recent outbreaks of Salmonella Enteritidis infections . The flies were separated by species into pools for microbiological testing . A total of 15 species pools of houseflies, Musca domestica L., and 7 species pools of bronze dump flies, Hydrotaea aenescens (Wiedemann) (Diptera: Muscidae), were analyzed . Salmonella Enteritidis was isolated from 2 of the 15 pools of houseflies . Other species of Salmonella were isolated from three pools of flies, including Salmonella Infantis from houseflies and from dump flies and Salmonella Heidelberg from houseflies . Salmonella Mbandaka was isolated from a lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae).

J Food Prot, 2000 Jul, 63(7), 876 - 83
Attachment and growth of Salmonella Chester on apple fruits and in vivo response of attached bacteria to sanitizer treatments; Liao CH et al.; Attachment and growth of Salmonella Chester on fresh-cut apple disks and in vivo response of attached bacteria to sanitizer treatments were investigated . Apple disks (14 mm in diameter and 3 to 4 mm in thickness) were immersed in a bacterial suspension that contained 8.17 log CFU/ml of Salmonella Chester and air dried at room temperature for 10 min . After two rinses, the population of Salmonella Chester retained on apple disks that contained no skin was 13 to 19% higher than that retained on disks that contained skin, indicating that Salmonella Chester attached more firmly to the surfaces of injured tissue than to the unbroken skin . The number of bacteria attached to the disk was not affected by the immersion time but was directly proportional to the concentration of bacteria in the suspension . The distribution of artificially inoculated Salmonella Chester on the surfaces of three different parts of whole fruit was determined; 94% of attached bacteria was found on the stem and calyx cavity areas and 6% on the skin of the remaining area of the fruit . Despite their acidic pH (4.1), apple disks supported the growth of Salmonella Chester at 20 degrees C but not at 8 degrees C . All four sanitizers tested in the study, including 6% hydrogen peroxide, 2% trisodium phosphate, 0.36% calcium hypochlorite, and 1.76% sodium hypochlorite, were effective in reducing the population of Salmonella Chester on apple disks by 1 to 2 logs . However, 5 to 13% of bacteria survived the sanitizer treatments . Hydrogen peroxide, which reduced the population of Salmonella Chester on skin by 3 to 4 logs and the population of bacteria on stem or calyx by 1 to 2 logs, was the most effective among the four sanitizers tested . Firm attachment of bacteria on calyx, stem, and injured tissue and partial resistance of attached bacteria to sanitizer treatments are two major obstacles to be considered when developing methods for cleaning and decontaminating apple fruits destined for juice production and fresh consumption.

J Food Prot, 2000 Jul, 63(7), 871 - 5
Reduction of Salmonella spp . and strains of Escherichia coli O157:H7 by gamma radiation of inoculated sprouts; Rajkowski KT et al.; There have been several recent outbreaks of salmonellosis and infections with Escherichia coli O157:H7 linked to the consumption of raw sprouts . Use of ionizing radiation was investigated as a means to reduce or to totally inactivate these pathogens, if present, on the sprouts . The radiation D value, which is the amount of irradiation in kilograys for a 1-log reduction in cell numbers, for these pathogens was established using a minimum of five doses at 19 +/- 1 degrees C . Before inoculation, the sprouts were irradiated to 6 kGy to remove the background microflora . The sprouts were inoculated either with Salmonella spp . cocktails made with either meat or vegetable isolates or with E . coli O157:H7 cocktails made with either meat or vegetable isolates . The radiation D values for the Salmonella spp . cocktails on sprouts were 0.54 and 0.46 kGy, respectively, for the meat and vegetable isolates . The radiation D values for the E . coli O157:H7 cocktails on sprouts were 0.34 and 0.30 kGy, respectively, for the meat and vegetable isolates . Salmonella was not detected by enrichment culture on sprouts grown from alfalfa seeds naturally contaminated with Salmonella after the sprouts were irradiated to a dose of 0.5 kGy or greater . Ionizing radiation is a process that can be used to reduce the population of pathogens on sprouts.

J Food Prot, 2000 Jul, 63(7), 867 - 70
Commercial field trial evaluation of mucosal starter culture to reduce Salmonella incidence in processed broiler carcasses; Bailey JS et al.; A series of four paired-house studies was conducted in Arkansas, Alabama, and Georgia (two farms) to determine the efficacy of Mucosal Starter Culture (MSC) in eliminating or reducing salmonellae in broiler chickens . Randomly designated chicks were treated twice with MSC . First they were sprayed with an MSC solution using a spray vaccination cabinet in the hatchery, and then they received MSC in the first drinking water at the growing house . Chicks were grown in identically constructed and equipped paired houses managed by the same grower . At the end of grow-out, broilers were tested for the presence of salmonellae on the farm and during processing . In three trials where no hatchery salmonellae were found, less salmonellae were found on MSC-treated chickens compared to untreated chickens . On the farm at the end of grow-out, salmonellae were detected in 54 of 150 untreated control chickens compared to 40 of 180 MSC-treated chickens . In the processing plant, significantly (P < or = 0.05) more salmonellae were detected on prechill untreated control carcasses (23 of 180) compared to MSC-treated carcasses (12 of 180) and on untreated postchill processed carcasses (9 of 180) compared to MSC-treated carcasses (0 of 180) . In one trial where appreciable (28% of egg shell samples) salmonellae was found before treatment with the MSC, more salmonellae were found in the treated birds than in the control birds both on the farm and after processing . These data confirm that when salmonellae levels were controlled in the hatchery, a significant reduction in the salmonellae was found on processed broiler carcasses treated with MSC and that this reduction in salmonellae was carried through processing to the final processed carcass, thus potentially reducing consumer exposure to salmonellae.

J Bacteriol, 2000 Aug, 182(16), 4406 - 13
Tissue-specific gene expression identifies a gene in the lysogenic phage Gifsy-1 that affects Salmonella enterica serovar typhimurium survival in Peyer's patches; Stanley TL et al.; In vivo expression technology was used to identify Salmonella enterica serovar Typhimurium genes that are transcriptionally induced when the bacteria colonize the small intestines of mice . These genes were subsequently screened for those that are transcriptionally inactive during the systemic stages of disease . This procedure identified gipA, a gene that is specifically induced in the small intestine of the animal . The gipA gene is carried on the lambdoid phage Gifsy-1 . Consistent with the expression profile, the sole defect conferred by a gipA null mutation is in growth or survival in a Peyer's patch . The gipA strain is wild type in its ability to initially colonize the small intestine and invade the intestinal epithelium . The mutant also survives and propagates at wild-type levels during the systemic stages of disease . The gipA open reading frame is homologous to a family of putative insertion sequence elements, although our evidence shows that transposition is not required for gipA function in the Peyer's patch . These results suggest that the bacteria sense and respond to the particular environment of the Peyer's patch, a critical site for the replication of Salmonella serovar Typhimurium.

J Bacteriol, 2000 Aug, 182(16), 4375 - 9
rpoS mutants in archival cultures of Salmonella enterica serovar typhimurium; Sutton A et al.; Long-term survival under limited growth conditions presents bacterial populations with unique environmental challenges . The existence of Salmonella enterica serovar Typhimurium cultures undisturbed in sealed nutrient agar stab vials for 34 to 45 years offered a unique opportunity to examine genetic variability under natural conditions . We have initiated a study of genetic changes in these archival cultures . We chose to start with examination of the rpoS gene since, among gram-negative bacteria, many genes needed for survival are regulated by RpoS, the stationary-phase sigma factor . In each of 27 vials examined, cells had the rpoS start codon UUG instead of the expected AUG of Salmonella and Escherichia coli strains recorded in GenBank . Ten of the 27 had additional mutations in the rpoS gene compared with the X77752 wild-type strain currently recorded in GenBank . The rpoS mutations in the 10 strains included two deletions as well as point mutations that altered amino acid sequences substantially . Since these stored strains were derived from ancestral cells inoculated decades ago and remained undisturbed, it is assumed that the 10 rpoS mutations occurred during storage . Since the remaining 17 sequences were wild type (other than in the start codon), it is obvious that rpoS remained relatively stable during decades of sealed storage.

Toxicol Sci, 2000 Aug, 56(2), 351 - 6
Mutagenicity studies of benzidine and its analogs: structure-activity relationships; Chung KT et al.; The Ames SALMONELLA:/microsome assay was employed to test the mutagenicity of benzidine and its analogs using strains TA98 and TA100 in the presence and absence of Aroclor 1254-induced rat S9 mix . 3,3'-Dichlorobenzidine-2HCl and 4,4'-dinitro-2-biphenylamine were directly mutagenic to TA98, while 4,4'-dinitro-2-biphenylamine was directly mutagenic to both TA98 and TA100 in the absence of S9 mix . 2-Aminobiphenyl, 3-aminobiphenyl, and 3,3'-5,5'-tetramethylbenzidine were not mutagenic in either strains in the presence or absence of S9 . In the presence of S9 mix, 4-aminobiphenyl, benzidine, 3, 3'-dichlorobenzidine-2HCl, 3,3'-dimethoxybenzidine, 3,3'-4, 4'-tetraaminobiphenyl, o-tolidine, N, N-N', N'-tetramethylbenzidine, and 4,4'-dinitro-2-biphenylamine were mutagenic to TA98; 4-aminobiphenyl, 3,3'-dichlorobenzidine-2HCl, 3, 3'-dimethoxybenzidine, and 4,4'-dinitro-2-biphenylamine were mutagenic to TA100 . Physicochemical parameters of these compounds including oxidation potentials, the energy difference between the lowest unoccupied molecular orbital and the highest occupied molecular orbital, ionization potentials, dipole moment, relative partition coefficient, and basicity did not correlate with their bacterial mutagenic activities.

Acta Paediatr Taiwan, 2000 Jan-Feb, 41(1), 43 - 6
Toxic megacolon in Salmonella colitis: report of two cases; Tiao MM et al.; Toxic megacolon is a complication that usually presents in inflammatory bowel disease such as ulcerative colitis or Crohn's disease . It also occurs in typhoid fever, acute bacillary dysentery, amebic colitis, ischemic colitis, pseudomembranous colitis and severe salmonellosis . This report describes the occurrence of toxic megacolon in two young children with Salmonella colitis manifesting as abdominal distension, diarrhea and fever . The clinical course of these two cases suggests that toxic megacolon is a severe complication of salmonellosis in children, irrespective of the use of antibiotics . In the light of its paucity in children and severity, accurate diagnosis and appropriate intensive medical-surgical management is essential.

Acta Paediatr Taiwan, 2000 Jan-Feb, 41(1), 28 - 32
Typhoid fever in children: a fourteen-year experience; Chiu CH et al.; From 1982 to 1995, 71 children admitted in our medical center were diagnosed to have typhoid fever by culture or serology . Of the 71 children, most (83%) were aged 5-15 years . These children usually presented with fever and gastrointestinal symptoms, including abdominal pain, diarrhea, nausea or vomiting, and constipation . Hepatosplenomegaly was the most common physical sign observed and abdominal tenderness ranked the second . Thrombocytopenia occurring in 9 patients (13%) was the most common mode of complication . Other complications included intestinal perforation (3%), rectal bleeding (3%), ascites or pleural effusion (4%), and meningitis (1%) . The incidence of complications tended to be higher among children 5 years of age or older (p = 0.31) . Most patients responded well to appropriate antimicrobial therapies . There was no mortality . Relapse was observed in two children, although both had received 10 days of chloramphenicol therapy . The clinical isolates of Salmonella typhi were susceptible in vitro to all the antibiotics tested, including chloramphenicol, which, however, showed a higher MIC90 level than other drugs tested . In conclusion, there were age-specific differences of typhoid fever in children in terms of the incidence and morbidity and antibiotic resistance of S . typhi has not been a problem in this area at least up to 1995.

Acta Paediatr Taiwan, 1999 Sep-Oct, 40(5), 339 - 40
Typhoid fever presenting as infection-associated hemophagocytic syndrome: report of one case; Chien YH et al.; This report describes a 13-year-old boy who had high fever with severe pancytopenia and acute psychosis as initial presentation . Bone marrow examination was compatible with infection-associated hemophagocytic syndrome (IAHS) . Blood culture showed no growth of bacteria while the culture of bone marrow yielded Salmonella typhi . The clinical condition stabilized shortly after the use of ceftriaxone . This case illustrates that typhoid fever must be included in the differential diagnosis of IAHS . In cases with IAHS, bacterial culture as well as morphological study of bone marrow is necessary for the evaluation of etiological agent and to avoid injudicious use of chemotherapy.

Am J Epidemiol, 2000 Jul 15, 152(2), 171 - 7
How many foodborne outbreaks of Salmonella infection occurred in France in 1995? Application of the capture-recapture method to three surveillance systems; Gallay A et al.; Despite control measures, foodborne outbreaks of non-typhi Salmonella infection continue to occur in developed countries . The authors aimed to assess the number of foodborne Salmonella outbreaks that occurred in France in 1995 using a capture-recapture approach . Data from three sources--the National Public Health Network (NPHN), the Ministry of Agriculture (MA), which receives mandatory notification, and the National Salmonella and Shigella Reference Center (NRC)-were collected . Matching algorithms permitted identification of matched outbreaks . The total number of outbreaks was estimated by log-linear modeling taking into account source dependencies and the variable catchability . The final estimate was adjusted for the positive predictive value (66%) of the NRC case definition . The dependence between the NPHN and the MA was also evaluated by means of a qualitative survey . A total of 716 foodborne Salmonella outbreaks were reported to the three sources, and 108 matches were identified . The best-fitting model, taking into account a positive dependence between the NPHN and MA sources, gave an estimate of 757 outbreaks . The sensitivity was 15% for the NPHN, 10% for the MA, and 50% for the NRC . In France, routine mandatory reporting of foodborne Salmonella outbreaks is very incomplete, and it is not representative of the serotype and the type of outbreak.

J Vet Med Sci, 2000 Jun, 62(6), 615 - 9
Detection of Salmonella by using the colorimetric DNA/rRNA sandwich hybridization in microtiter wells; Namimatsu T et al.; A rapid and readily available DNA probe kit was developed for the detection of Salmonella spp . This kit utilized the colorimetric DNA/rRNA sandwich hybridization method in microtiter wells . Within 3 hr Salmonella spp . in selective enrichment broth cultures were detected by the DNA probe kit . The kit effectively identified all of 187 strains of Salmonella tested and yielded no false-positive reactions in the examination of 674 pure cultures of non-salmonellae . The DNA probe kit could detect 10(5) cfu/ml in pure culture . A total of 379 naturally contaminated samples (raw chicken meat, liquid egg, animal feeds, poultry feces and frozen foods) were tested, both by the standard culture method and the DNA probe kit . The 169 of these samples were culture positive and 210 were culture negative . The sensitivity of the DNA probe kit was 98.2% (166/169) and the specificity was 99.5% (209/210) . These results show that the DNA probe kit is a useful tool to examine a large number of various samples for contamination by Salmonella spp . in food and livestock industry.

J Vet Med Sci, 2000 Jun, 62(6), 565 - 70
Chronological recognition by chicken of antigenic polypeptides in Salmonella enteritidis with different plasmid profiles: relationship to infection rate; Barbour EK et al.; The antigenic polypeptides in Salmonella Enteritidis (SE) were chronologically recognized by the chicken immune system, using Western immunoblotting . Broiler chicks challenged at three days of age with SE strain carrying the most prevalent plasmid profile of 14.1 and about (approximately) 50 kb were bled at 17, 24, 31, 38 and 45 days of age . Pooled sera of blood collected at each age was reacted by Western immunoblotting with banded polypeptides of three predominant SE strains that acquired the following respective plasmid profiles: 14.1 kb; 14.1 and approximately 50.0 kb; and 1.8, 14.1 and approximately 50.0 kb . The immunoblots of each pooled sera collected at a specific age against the three SE strains were similar . More specifically, the early immune response at 17 days of age had antibodies recognizing only one polypeptide in the three SE strains namely, the 35.8 kDa . At 24 or 31 days of age, the acquired immunity to infection had antibodies recognizing five similar polypeptides in the three SE strains namely, the 14.4 (fimbriae protein), 21.5 (fimbriae protein), 30.5, 35.8, and 66.2 kDa . At 38 and 45 days of age, the antibodies recognized additional polypeptides namely, the 41.5 and 55.6 kDa, respectively . The recognition of the 41.5 and 55.6 kDa polypeptides at 45 days of age was associated with higher invasiveness of SE to spleens and livers (15.6%) and in higher cecal colonization (59.4%) in comparison to absence of recognition to the two polypeptides at 31 days of age associated with low infectivity to spleens (0%), livers (3.1%), and ceca (9.4%).

Przegl Lek, 2000, 57(1), 54 - 5
{Hemolytic-uremic syndrome in a patient with bacterial food poisoning}; Kalinowska-Nowak A et al.; A rare case of a 47-year-old man with bacterial food poisoning due to Salmonella enteritidis, complicated by haemolitic-uraemic syndrome was described.

Microb Pathog, 2000 Aug, 29(2), 121 - 6
Experimental Salmonella typhi infection in the domestic pig, Sus scrofa domestica; Metcalf ES et al.; The domestic pig, Sus scrofa domestica, was examined as a model for typhoid fever, a severe and systemic disease of humans caused by Salmonella typhi . Six pigs were inoculated 1 week post-weaning with approximately 10(10)colony forming units (cfu) of wild type Salmonella typhi strain ISP1820 intranasally and observed for 3 weeks . S . typhi was cultured from the tonsils of 50% of the pigs at necropsy . Cultures from all other organs analysed (ileum, colon, spleen and liver) were negative . No clinical or histopathological signs of disease were observed . Pigs inoculated in parallel with swine-virulent S . choleraesuis all exhibited signs of systemic salmonellosis indicating that the parameters of the experimental infection with S . typhi (e.g . route) were appropriate . Whereas the pig has a gastrointestinal tract that is very similar to humans, our results indicated that the unique features of host and microbe interaction needed to produce typhoid fever were not mimicked in swine . Nevertheless, our observation of tonsillar involvement was consistent with former observations of S . choleraesuis and S . typhimurium infections in swine and supports a role for the tonsil in all porcine salmonella infections .

J Comp Pathol, 2000 Jul, 123(1), 1 - 6
Effect of experimental zinc deficiency on immunological responses in Salmonella-infected guinea-pigs; Gupta RP et al.; Cellular and humoral immune responses to Salmonella dublin infection were studied in guinea-pigs given zinc-deficient (ZnD) or zinc-adequate (ZnA) diet, containing 1.03 or 52.4 mg Zn/kg, respectively . On day 30, each animal of each dietary group was inoculated intraperitoneally with 10(6)viable cells of S . dublin strain 493 . On the 15th day after infection, the immune responses were assessed by skin hypersensitivity (SH) tests and enzyme-linked immunosorbent assay (ELISA) for serum antibody with Salmonella -extract antigen . ZnD animals had significantly decreased ability to produce Salmonella -specific immediate and delayed type SH responses . These results were further substantiated by histological examination of skin sections . The ELISA indicated significantly lower Salmonella -specific serum antibody titres in ZnD animals than in ZnA animals . Mean viable counts of S . dublin in the liver and spleen of ZnD animals were significantly higher than those in ZnA animals .

Emerg Infect Dis, 2000 Jul-Aug, 6(4), 420 - 1
Drug-resistant Salmonella enterica serotype paratyphi A in India; Chandel DS et al.; The incidence of enteric fever caused by Salmonella enterica serotype Paratyphi A has been increasing in India since 1996 . In 1998, the incidence of enteric fever caused by drug- resistant S . Paratyphi A abruptly increased in the New Delhi region . In the first 6 months of 1999, 32% of isolates were resistant to both chloramphenicol and cotrimoxazole and another 13% were resistant to more than two antibiotics.

Emerg Infect Dis, 2000 Jul-Aug, 6(4), 401 - 3
Antimicrobial resistance in Salmonella enteritidis, southern Italy, 1990-1998; Nastasi A et al.; During 1990 to 1998, we identified multidrug-resistant isolates of Salmonella Enteritidis in southern Italy . Plasmids containing class I integrons and codifying for synthesis of extended- spectrum beta-lactamases were detected . Active surveillance for resistance to antimicrobial agents is needed to guard against the possible spread of resistant clones.

Anal Chem, 2000 Jul 1, 72(13), 2809 - 13
A Salmonella detection system using an engineered DNA binding protein that specifically captured a DNA sequence; Takeuchi A et al.; We have developed a novel method for the detection with high selectivity of a double-stranded DNA fragment using an engineered DNA-binding protein, DnaA IV, a fusion protein of the DNA-binding domain of DnaA and glutathione S-transferase . The DNA fragment detection system is based on DNA-protein interaction and consists of sequence-specific binding of DnaA IV with a DNA fragment containing the DnaA box . DnaA IV, while not capturing other DNA fragments, specifically captured that containing the DnaA box . Because the oriC fragment containing the DnaA box could be specifically amplified by PCR from the genus Salmonella, the DNA fragment detection system was adapted for the detection of Salmonella . The Salmonella detection system using PCR amplification and the engineered DNA-binding protein could distinguish 104 cfu/mL Salmonella from 106 cfu/ mL contaminating bacteria.

Enferm Infecc Microbiol Clin, 2000 Mar, 18(3), 125 - 32
{Epidemiology of non-typhoid salmonellosis in a hospital in Pontevedra (1994-1997)}; Bellver P et al.; BACKGROUND: Since data on non-typhoidal salmonellosis in our health care area are scarce, we undertook an epidemiological study covering a four year period (1994-1997) . METHODS: Retrospective descriptive study carried out through review of the medical and clinical microbiologic records at Hospital Provincial de Pontevedra . Culture, isolation, identification, antibiotic susceptibility and serotypification were done according to usual Clinical Microbiology protocols . RESULTS: Along the period under study 459 cases of non-typhoidal salmonellosis were diagnosed . The relative incidence was higher among pediatric than adult patients . Between 1994-1996 top incidence was detected in August, while in 1997 another maximum was found in April, closely related to climatic variations . The most frequent serogroup was D, with an increase in serogroup B since 1996 . We found 16 different serotypes, being the more frequent in decreasing order Enteritidis (87.2%), Typhimurium (3.6%) and Hadar (2.3%) . This distribution shows differences with regard to other national series covering a similar period of time . The more frequently detected antibiotic resistance was to ampicillin (39.0% strains), ampicillin-sulbactam (17.6%) and nalidixic acid (5.9%) . Neither 3rd-generation cephalosporines nor fluoroquinolones resistance was detected . Serotype Typhimurium was the most resistant . We found association between certain resistance patterns and serotypes Hadar, Paratyphi B and Typhimurium . Most diagnosed cases corresponded to acute gastroenteritis (95.6%) . Patients under 3 and over 69 suffered more frequently from extraintestinal salmonellosis . CONCLUSIONS: The high incidence of alimentary toxinfection due to Salmonella spp . in our area should warrant strict epidemiological surveillance programmes to detect sources of infection, evaluate sanitary control measures and use of antibiotics.

J Med Assoc Thai, 1997 Oct, 80(10), 613 - 8
Nontyphoidal Salmonella diarrhea in Thai children: a study at Bamrasnaradura Hospital, Nonthaburi, Thailand; Moolasart P et al.; From July 1, 1994 to June 30, 1996, 394 children with Nontyphoidal Salmonella diarrhea were studied at Bamrasnaradura Infectious Disease Hospital in Thailand . The ages ranged from 1 month to 12 years (mean, 1.4 years) . Eighty-seven per cent of patients were in the first 2 years of life . Diarrhea, mostly acute with watery stool and fever were the most common presenting symptoms . The duration of diarrhea ranged from 1 to 20 days (mean, 5.2 days) . Salmonella group B was the most common serogroup (56.1%) . Most isolates were multiresistant strains, however, they were all sensitive to norfloxacin . Four (1%) patients were HIV-infected . Pneumonia found in 2 patients (0.5%) and septicemia in 1 patient (0.3%) . None of the patients died . We conclude that nontyphoidal Salmonella diarrhea in children is still endemic in Thailand, especially among infants and high multidrug resistance occurs.

Arthritis Rheum, 2000 Jul, 43(7), 1527 - 34
Modification of disease outcome in Salmonella-infected patients by HLA-B27; Ekman P et al.; OBJECTIVE: To study whether HLA-B27 modifies the outcome of Salmonella infection in vivo . METHODS: The frequency of HLA-B27 was determined in 198 Salmonella-infected patients and 100 healthy controls by immunofluorescence and polymerase chain reaction . The excretion of Salmonella was monitored at monthly intervals . The symptoms of acute infection and possible joint involvement were evaluated using questionnaires . RESULTS: Thirty-eight of 198 Salmonella-infected patients (19.2%) and 13 of 100 healthy controls (13.0%) were HLA-B27 positive . The excretion of Salmonella did not differ significantly between HLA-B27-positive and -negative patients, or for patients with versus those without joint symptoms . As many as 35 patients (17.7%) reported Salmonella-triggered joint symptoms . Three of 14 patients (21.4%) with arthralgia, 5 of 13 patients (38.5%) with probable reactive arthritis (ReA), and 6 of 8 patients (75%) with confirmed ReA were HLA-B27 positive . The duration and severity of joint symptoms directly correlated with HLA-B27 positivity . Women reported Salmonella-induced pain and swelling of joints more frequently than men (P = 0.07 and P = 0.03, respectively) . Patients with Salmonella-triggered joint symptoms reported abdominal pain and headache more frequently than patients without joint symptoms (P = 0.05 and P = 0.004, respectively) . CONCLUSION: HLA-B27 did not (at least, not strongly) confer susceptibility to Salmonella infection . Salmonella excretion correlated neither with HLA-B27 positivity nor with the occurrence of joint symptoms . Joint symptoms were surprisingly common during or after Salmonella infection . HLA-B27-positive patients had a significantly increased risk of developing joint and tendon symptoms . Moreover, HLA-B27 positivity correlated with the development of more severe and prolonged joint symptoms.

Commun Dis Public Health, 2000 Jun, 3(2), 95 - 100
Four linked outbreaks of Salmonella enteritidis phage type 4 infection--the continuing egg threat; Ejidokun OO et al.; Four outbreaks of Salmonella enteritidis phage type (PT) 4 occurred among guests at functions for which a single commercial caterer supplied food . Retrospective cohort studies were used to describe the epidemiology of three of these outbreaks and identify the vehicle(s) responsible . Of 172 guests at these three events, 47 fitted the clinical case definition for illness and 24 cases were confirmed to have S . enteritidis PT4 infection . Food containing raw egg was identified epidemiologically as the likely vehicle of infection in two of the three outbreaks (odds ratios (OR) and 95% confidence intervals 9.1 (2.2-39.9) and 6.9 (1.2-46.4)) . Logistic regression analysis yielded OR = 10.7 (p = 0.0022) and OR = 9.3 (p = 0.015) for egg consumption in two of the outbreaks . These outbreaks highlighted the continuing need to remind the public and commercial caterers of the potential high risks of contracting salmonella from shell eggs . Education of caterers includes advice to obtain eggs and other products from reputable and identifiable suppliers.

Commun Dis Public Health, 2000 Jun, 3(2), 90 - 4
Survey of raw egg use by home caterers; Sin J et al.; Outbreaks of egg related salmonella infection continue to occur despite over ten years of national guidance on this subject . Fifty-four out of 70 registered home caterers in Cheshire responded to a telephone questionnaire, which revealed that a sixth prepared raw egg dishes containing shell eggs, none used pasteurised egg, and advice about storage of eggs and handwashing was not always followed . A postal questionnaire sent to 13 wholesalers and major supermarket chains showed that pasteurised egg was available in large packs from wholesalers but not from supermarkets . It is time to consider new approaches to reinforce advice about pasteurised egg use for raw egg dishes, storage, and measures to prevent cross contamination . These findings have implications for the training of home caterers and the general public.

Vet Rec, 2000 Jun 17, 146(25), 721 - 8
Pulmonary pathology of harbour porpoises (Phocoena phocoena) stranded in England and Wales between 1990 and 1996; Jepson PD et al.; The pathological changes observed in the lungs of 197 freshly dead to moderately decomposed harbour porpoises (Phocoenaphocoena) stranded in England and Wales between October 1990 and December 1996 were reviewed . In 135 (69 per cent of the cases) macroscopic nematode infections of the bronchial tract with Pseudalius inflexus and Torynurus convolutus, either singly or in combination, were recorded, and 106 (54 per cent) also had P inflexus within the pulmonary blood vessels . All the macroscopically parasitised porpoises were adults or juveniles although two neonates had histological evidence of nematode infection . There were 62 cases of mild to severe, subacute to chronic bronchitis and bronchiolitis, 113 cases of mild to severe chronic granulomatous interstitial pneumonia, and 34 cases of mild to severe vasculitis or thrombovasculitis of pulmonary blood vessels attributable to these nematode infections . In 35 cases necropurulent or purulent (broncho)pneumonias were attributed either to secondary bacterial infections of the lungs or to septicaemias associated in seven cases with Streptococcus canis, in two cases with group B Salmonella species, in one case with Escherichia coli and in one case with Streptococcus lactis . The pulmonary lesions in 67 animals known or diagnosed to have been entrapped in fishing gear were non-specific and included persistent foam in the airways in 45 cases, diffuse congestion in 53, oedema in 50, and multifocal intra-alveolar haemorrhage in 33 cases . Seven cases of acute fibrinous or chronic fibrous pleuritis, seven cases of chronic necropurulent pneumonia associated with mycotic infections, four porpoises with traumatic lesions of the thorax and other parts of the body consistent with fatal attack from bottlenose dolphins (Tursiops truncatus), and one case of diffuse bronchointerstitial pneumonia associated with generalised morbillivirus infection were also recorded.

Infect Immun, 2000 Aug, 68(8), 4782 - 5
Salmonella enterica serovars gallinarum and pullorum expressing Salmonella enterica serovar typhimurium type 1 fimbriae exhibit increased invasiveness for mammalian cells; Wilson RL et al.; Salmonella enterica serovars Gallinarum and Pullorum are S . enterica biotypes that exhibit host specificity for poultry and aquatic birds and are not normally capable of causing disease in mammalian hosts . During their evolution toward host restriction serovars Gallinarum and Pullorum lost their ability to mediate mannose-sensitive hemagglutination (MSHA), a phenotype correlated with adherence to certain cell types . Because adherence is an essential requirement for invasion of cells by bacterial pathogens, we examined whether MHSA type 1 fimbriae would increase the ability of serovars Pullorum and Gallinarum to invade normally restrictive cells . Serovars Gallinarum and Pullorum expressing S . enterica serovar Typhimurium strain LT2 type 1 fimbriae exhibited a 10- to 20-fold increased ability to adhere to and a 20- to 60-fold increased invasion efficiency of the human epithelial HEp-2 cell line . Invasion was accompanied by extensive ruffling of the membranes of the HEp-2 cells . In a murine ligated ileal loop model, a 32% increase in the number of M-cell ruffles was seen when serovar Gallinarum expressed serovar Typhimurium type 1 fimbriae.

Infect Immun, 2000 Aug, 68(8), 4647 - 52
Constitutive expression of the Vi polysaccharide capsular antigen in attenuated Salmonella enterica serovar typhi oral vaccine strain CVD 909; Wang JY et al.; Live oral Ty21a and parenteral Vi polysaccharide vaccines provide significant protection against typhoid fever, albeit by distinct immune mechanisms . Vi stimulates serum immunoglobulin G Vi antibodies, whereas Ty21a, which does not express Vi, elicits humoral and cell-mediated immune responses other than Vi antibodies . Protection may be enhanced if serum Vi antibody as well as cell-mediated and humoral responses can be stimulated . Disappointingly, several new attenuated Salmonella enterica serovar Typhi oral vaccines (e.g., CVD 908-htrA and Ty800) that elicit serum O and H antibody and cell-mediated responses following a single dose do not stimulate serum Vi antibody . Vi expression is regulated in response to environmental signals such as osmolarity by controlling the transcription of tviA in the viaB locus . To investigate if Vi antibodies can be stimulated if Vi expression is rendered constitutive, we replaced P(tviA) in serovar Typhi vaccine CVD 908-htrA with the constitutive promoter P(tac), resulting in CVD 909 . CVD 909 expresses Vi even under high-osmolarity conditions and is less invasive for Henle 407 cells . In mice immunized with a single intranasal dose, CVD 909 was more immunogenic than CVD 908-htrA in eliciting serum Vi antibodies (geometric mean titer of 160 versus 49, P = 0.0007), whereas O antibody responses were virtually identical (geometric mean titer of 87 versus 80) . In mice challenged intraperitoneally with wild-type serovar Typhi 4 weeks after a single intranasal immunization, the mortality of those immunized with CVD 909 (3 of 8) was significantly lower than that of control mice (10 of 10, P = 0.043) or mice given CVD 908-htrA (9 of 10, P = 0.0065).

Infect Immun, 2000 Aug, 68(8), 4485 - 91
Salmonella enterica serovar typhimurium waaP mutants show increased susceptibility to polymyxin and loss of virulence In vivo; Yethon JA et al.; In Escherichia coli, the waaP (rfaP) gene product was recently shown to be responsible for phosphorylation of the first heptose residue of the lipopolysaccharide (LPS) inner core region . WaaP was also shown to be necessary for the formation of a stable outer membrane . These earlier studies were performed with an avirulent rough strain of E . coli (to facilitate the structural chemistry required to properly define waaP function); therefore, we undertook the creation of a waaP mutant of Salmonella enterica serovar Typhimurium to assess the contribution of WaaP and LPS core phosphorylation to the biology of an intracellular pathogen . The S . enterica waaP mutant described here is the first to be both genetically and structurally characterized, and its creation refutes an earlier claim that waaP mutations in S . enterica must be leaky to maintain viability . The mutant was shown to exhibit characteristics of the deep-rough phenotype, despite its ability to produce a full-length core capped with O antigen . Further, phosphoryl modifications in the LPS core region were shown to be required for resistance to polycationic antimicrobials . The waaP mutant was significantly more sensitive to polymyxin in both wild-type and polymyxin-resistant backgrounds, despite the decreased negative charge of the mutant LPSs . In addition, the waaP mutation was shown to cause a complete loss of virulence in mouse infection models . Taken together, these data indicate that WaaP is a potential target for the development of novel therapeutic agents.

Antimicrob Agents Chemother, 2000 Aug, 44(8), 2166 - 9
Antimicrobial resistance and spread of class 1 integrons among Salmonella serotypes; Guerra B et al.; The resistance profiles, for 15 antimicrobial agents, of 333 Salmonella strains representing the most frequent nontyphoidal serotypes, isolated between 1989 and 1998 in a Spanish region, and 9 reference strains were analyzed . All strains were susceptible to amikacin, ceftazidime, ciprofloxacin, and imipenem, and 31% were susceptible to all antimicrobials tested . The most frequent types of resistance were to sulfadiazine, tetracycline, streptomycin, spectinomycin, ampicillin, and chloramphenicol (ranging from 46 to 22%); 13% were resistant to these six drugs . This multidrug resistance pattern was found alone or together with other resistance types within serotypes Typhimurium (45%), Panama (23%), and Virchow (4%) . Each isolate was also screened for the presence of class 1 integrons and selected resistance genes therein; seven variable regions which carried one (aadA1a, aadA2, or pse-1) or two (dfrA14-aadA1a, dfrA1-aadA1a, oxa1-aadA1a, or sat1-aadA1a) resistance genes were found in integrons.

Int J Food Microbiol, 2000 Jun 30, 58(1-2), 107 - 11
Analysis of Salmonella serotypes from selected carcasses and raw ground products sampled prior to implementation of the Pathogen Reduction; Hazard Analysis and Critical Control Point Final Rule in the US; Schlosser W et al.; In July 1996, the US Department of Agriculture (USDA), Food Safety and Inspection Service (FSIS), published the Pathogen Reduction; Hazard Analysis and Critical Control Point (HACCP) Systems final rule to improve food safety of meat and poultry products . The final rule established, among other requirements, pathogen reduction performance standards for Salmonella for food animal carcasses and raw ground products . The final rule is to be fully implemented in three stages in successively smaller federally inspected meat and poultry slaughter and processing establishments . Implementation began in January 1998 and was completed in January 2000 . Samples of carcasses of four species of food animals (cattle, swine, chickens, turkeys), and raw ground product from each of these species, were collected by FSIS from establishments prior to implementation of the final rule and cultured for Salmonella . This paper reports Salmonella serotype results of samples collected from June 1997 through August 1998 . These results represent a baseline for future comparisons.

Trans R Soc Trop Med Hyg, 2000 Mar-Apr, 94(2), 212 - 5
Antibiotic susceptibility and genotypes of non-typhi Salmonella isolates from children in Kilifi on the Kenya coast; Oundo JO et al.; A 4-year retrospective study was undertaken at the Kilifi District Hospital on the coast of Kenya to determine the antibiotic-susceptibility patterns and genotypes of non-typhi Salmonella (NTS) isolates from children . Overall, during the period 1994-97, positive cultures were obtained from 543 (14%) of 3885 blood samples, 364 (30%) of 1210 stool samples and 143 (11%) of 1283 cerebrospinal fluid (CSF) samples . NTS were isolated from 151 (27.8%), 72 (19.8%), and 11 (7.7%) of these positive cultures, respectively . The total 234 NTS isolates were serotyped: the most frequent were Salmonella enterica serotype Enteritidis (41%) and S . enterica serotype Typhimurium (38%) . Antibiotic sensitivity testing was done using ampicillin (amp), chloramphenicol (chl), gentamicin (cn), co-trimoxazole (s-t), cefuroxime (cxm), ciprofloxacin (cip), cefotaxime (ctx), amoxicillin-clavulanic acid 20 micrograms-10 micrograms (amc), and tobramycin (tob) . Of the 234 isolates, 43 were sensitive to all antibiotics tested and 133 were multiple drug resistant (MDR) . The most common resistance type seen was amp, cn, cxm, s-t, ctx, amc, tob (36/234) . Our results indicate a high proportion of MDR amongst the isolates from Kilifi . We conclude that 2 major serotypes of salmonella, i.e., S . enterica serotype Typhimurium and S . enterica serotype Enteritidis, of micro-epidemic nature that have been previously unrecognized in Kilifi are responsible for infection in Kilifi district on the coast of Kenya and that over half (56.8%) of total NTS isolates are MDR.

Rev Esp Quimioter, 1999 Dec, 12(4), 366 - 8
{Evolution of resistance to quinolones in Salmonella enterica in our setting}; Ruiz M et al.; Salmonella enterica is mainly associated with acute gastroenteritis; however, it is also associated with other more severe disease processes, for which quinolones are the treatment of choice . We retrospectively studied the evolution of resistance to nalidixic acid and ciprofloxacin of all the clinical isolates of S . enterica from 1992 to 1998 in our hospital environment . A total of 848 strains from feces, blood and other locations were studied . We detected an increase in the resistance to nalidixic acid from 12% in 1992 to 21.3% in 1998, especially in the Enteritidis and Hadar serotypes . We did not detect resistance to ciprofloxacin, but there was in increase in the MIC in the nalidixic acid-resistant strains . Although this is interpreted as sensitive according the the NCCLS criteria, if we apply the cutoff points established by MENSURA, 89.46% of the strains do not fit into this category (S <0.12 mg/l) . This puts into question the utility of quinolones in the long-term treatment of severe disease processes produced by this type of strain.

J Bacteriol, 2000 Aug, 182(15), 4304 - 9
Reduction of Cob(III)alamin to Cob(II)alamin in Salmonella enterica serovar typhimurium LT2; Fonseca MV et al.; Reduction of the cobalt ion of cobalamin from the Co(III) to the Co(I) oxidation state is essential for the synthesis of adenosylcobalamin, the coenzymic form of this cofactor . A cob(II)alamin reductase activity in Salmonella enterica serovar Typhimurium LT2 was isolated to homogeneity . N-terminal analysis of the homogeneous protein identified NAD(P)H:flavin oxidoreductase (Fre) (EC 1.6.8.1) as the enzyme responsible for this activity . The fre gene was cloned, and the overexpressed protein, with a histidine tag at its N terminus, was purified to homogeneity by nickel affinity chromatography . His-tagged Fre reduced flavins (flavin mononucleotide {FMN} and flavin adenine dinucleotide {FAD}) and cob(III)alamin to cob(II)alamin very efficiently . Photochemically reduced FMN substituted for Fre in the reduction of cob(III)alamin to cob(II)alamin, indicating that the observed cobalamin reduction activity was not Fre dependent but FMNH(2) dependent . Enzyme-independent reduction of cob(III)alamin to cob(II)alamin by FMNH(2) occurred at a rate too fast to be measured . The thermodynamically unfavorable reduction of cob(II)alamin to cob(I)alamin was detectable by alkylation of the cob(I)alamin nucleophile with iodoacetate . Detection of the product, caboxymethylcob(III)alamin, depended on the presence of FMNH(2) in the reaction mixture . FMNH(2) failed to substitute for potassium borohydride in in vitro assays for corrinoid adenosylation catalyzed by the ATP:co(I)rrinoid adenosyltransferase (CobA) enzyme, even under conditions where Fre and NADH were present in the reaction mixture to ensure that FMN was always reduced . These results were interpreted to mean that Fre was not responsible for the generation of cob(I)alamin in vivo . Consistent with this idea, a fre mutant displayed wild-type cobalamin biosynthetic phenotypes . It is proposed that S . enterica serovar Typhimurium LT2 may not have a cob(III)alamin reductase enzyme and that, in vivo, nonadenosylated cobalamin and other corrinoids are maintained as co(II)rrinoids by reduced flavin nucleotides generated by Fre and other flavin oxidoreductases.

J Bacteriol, 2000 Aug, 182(15), 4227 - 33
Identification of an alternative nucleoside triphosphate: 5'-deoxyadenosylcobinamide phosphate nucleotidyltransferase in Methanobacterium thermoautotrophicum delta H; Thomas MG et al.; Computer analysis of the archaeal genome databases failed to identify orthologues of all of the bacterial cobamide biosynthetic enzymes . Of particular interest was the lack of an orthologue of the bifunctional nucleoside triphosphate (NTP):5'-deoxyadenosylcobinamide kinase/GTP:adenosylcobinamide-phosphate guanylyltransferase enzyme (CobU in Salmonella enterica) . This paper reports the identification of an archaeal gene encoding a new nucleotidyltransferase, which is proposed to be the nonorthologous replacement of the S . enterica cobU gene . The gene encoding this nucleotidyltransferase was identified using comparative genome analysis of the sequenced archaeal genomes . Orthologues of the gene encoding this activity are limited at present to members of the domain Archaea . The corresponding ORF open reading frame from Methanobacterium thermoautotrophicum Delta H (MTH1152; referred to as cobY) was amplified and cloned, and the CobY protein was expressed and purified from Escherichia coli as a hexahistidine-tagged fusion protein . This enzyme had GTP:adenosylcobinamide-phosphate guanylyltransferase activity but did not have the NTP:AdoCbi kinase activity associated with the CobU enzyme of S . enterica . NTP:adenosylcobinamide kinase activity was not detected in M . thermoautotrophicum Delta H cell extract, suggesting that this organism may not have this activity . The cobY gene complemented a cobU mutant of S . enterica grown under anaerobic conditions where growth of the cell depended on de novo adenosylcobalamin biosynthesis . cobY, however, failed to restore adenosylcobalamin biosynthesis in cobU mutants grown under aerobic conditions where de novo synthesis of this coenzyme was blocked, and growth of the cell depended on the assimilation of exogenous cobinamide . These data strongly support the proposal that the relevant cobinamide intermediates during de novo adenosylcobalamin biosynthesis are adenosylcobinamide-phosphate and adenosylcobinamide-GDP, not adenosylcobinamide . Therefore, NTP:adenosylcobinamide kinase activity is not required for de novo cobamide biosynthesis.

J Bacteriol, 2000 Aug, 182(15), 4207 - 15
Role of FliJ in flagellar protein export in Salmonella; Minamino T et al.; We isolated and characterized spontaneous mutants with defects in the 147-amino-acid Salmonella protein FliJ, which is a cytoplasmic component of the type III flagellar export apparatus . These mutants, including ones with null mutations, have the ability to form swarms on motility agar plates after prolonged incubation at 30 degrees C; i.e., they display a leaky motile phenotype . One mutant, SJW277, which formed significantly bigger swarms than the others, encoded only the N-terminal 73 amino acids of FliJ, one-half of the protein . At 30 degrees C, overproduction of this mutant protein improved, to wild-type levels, both motility and the ability to export both rod/hook-type (FlgD; hook capping protein) and filament-type (FliC; flagellin) substrates . At 42 degrees C, however, export was inhibited, indicating that the mutant FliJ protein was temperature sensitive . Taking advantage of this, we performed temperature upshift experiments, which demonstrated that FliJ is directly required for the export of FliC . Co-overproduction of FliJ and either of two export substrates, FliE or FlgG, hindered their aggregation in the cytoplasm . We conclude that FliJ is a general component of the flagellar export apparatus and has a chaperone-like activity for both rod/hook-type and filament-type substrates.

Am J Gastroenterol, 2000 Jun, 95(6), 1495 - 502
Phagocytosis, killing, lymphocyte-mediated antibacterial activity, serum autoantibodies, and plasma endotoxins in inflammatory bowel disease; Caradonna L et al.; OBJECTIVE: Alteration of mucosal and systemic immune responses may play an important role in the pathogenesis of inflammatory bowel disease (IBD) . The aim of this study was to evaluate natural immune responses (i.e., phagocytosis, killing, and antibacterial activity), serum autoantibodies (antineutrophil cytoplasmic antibodies {ANCA} and anti-lactoferrin {LF} antibodies), and plasma endotoxins in patients affected by ulcerative colitis (UC) and Crohn's disease (CD) . METHODS: Blood samples were obtained from 71 patients with UC, 32 patients with CD, and 32 control subjects . Disease activity was scored using Truelove's criteria in patients with UC and the Crohn's Disease Activity Index (CDAI) in patients with CD . Candida albicans served as a target for evaluation of phagocytosis and killing exerted by polymorphonuclear cells (PMN) and monocytes (MO), whereas Salmonella typhi was used for assessing lymphocyte-mediated antibacterial activity . ANCA were detected by indirect immunofluorescence, whereas anti-LF antibodies were assayed by means of enzyme-linked immunosorbent assay . Plasma endotoxins were measured by Limulus amoebocyte lysate assay . RESULTS: Phagocytosis and killing exerted by PMN and MO, as well as lymphocyte-mediated antibacterial activity, were significantly reduced (p < 0.0001) in patients affected by UC and CD in comparison with controls, irrespective of either disease activity or treatment . Plasma endotoxins were detected in 12/71 (17%) patients with UC, and in 10/32 (31%) patients with CD . ANCA were present in 42/71 (59%) patients with UC and in 3/32 (9%) patients with CD, whereas anti-LF antibodies were detected in 31 (44%) UC patients and in six (19%) CD patients . No significant differences in phagocytosis and killing exerted by PMN were found between ANCA-positive and ANCA-negative UC patients . CONCLUSIONS: Our data demonstrate an impairment of natural immunity exerted by peripheral blood phagocytes and lymphocytes in patients with UC and CD . ANCA and anti-LF antibodies were present mainly in UC patients but their presence did not affect PMN-mediated phagocytosis and killing . Finally, plasma endotoxins may contribute to the chronic inflammatory status, likely by inducing release of proinflammatory mediators.

Nature, 2000 Jul 6, 406(6791), 64 - 7
Parallel evolution of virulence in pathogenic Escherichia coli; Reid SD et al.; The mechanisms underlying the evolution and emergence of new bacterial pathogens are not well understood . To elucidate the evolution of pathogenic Escherichia coli strains, here we sequenced seven housekeeping genes to build a phylogenetic tree and trace the history of the acquisition of virulence genes . Compatibility analysis indicates that more than 70% of the informative sites agree with a single phylogeny, suggesting that recombination has not completely obscured the remnants of ancestral chromosomes . On the basis of the rate of synonymous substitution for E . coli and Salmonella enterica (4.7 x 10(-9) per site per year), the radiation of clones began about 9 million years ago and the highly virulent pathogen responsible for epidemics of food poisoning, E . coli O157:H7, separated from a common ancestor of E . coli K-12 as long as 4.5 million years ago . Phylogenetic analysis reveals that old lineages of E . coli have acquired the same virulence factors in parallel, including a pathogenicity island involved in intestinal adhesion, a plasmid-borne haemolysin, and phage-encoded Shiga toxins . Such parallel evolution indicates that natural selection has favoured an ordered acquisition of genes and the progressive build-up of molecular mechanisms that increase virulence.

Vet Microbiol, 2000 Jul 31, 75(2), 155 - 65
Genotypic characterisation by PFGE of Salmonella enterica serotype Enteritidis phage types 1, 4, 6, and 8 isolated from animal and human sources in three European countries; Laconcha I et al.; A total of 101 strains of Salmonella Enteritidis phage types (PT) 1, 4, 6, and 8 from Denmark, England and Spain were studied by PFGE to elucidate genetic relationships among strains isolated from animal, human and environmental sources between 1983 and 1997 . Analysis with Xba I, Bln I and Spe I enzymes showed that the power of discrimination of this method was increased by the combination of the three enzymes (D=0.802), subdividing the strains into 28 genomic groups or genotypes . Many of the PT1, PT4, and PT6 strains from the three countries shared the same PFGE combination profile A1-A1-A1, confirming the close relationship among these phage types and the protracted spread of a single clone over a large geographical area . In general, strains from Denmark showed more variation in their PFGE profiles than those from England and Spain . PT4 strains exhibited genetic homogeneity in the three countries independently of their sources and period of isolation . Spe I gave the highest index of discrimination among PT6 strains as evidenced by a variety of PFGE profiles . The data clearly confirmed that PT8 strains isolated in the three countries were of a unique clonal origin, and the PFGE combination profile A10-A10-A1 was predominant and specific for this phage type . It is concluded that PFGE, in combination with phage typing, represents a suitable tool for the epidemiological typing of Salmonella Enteritidis strains which could be used for investigations or surveillance of the international spread of these clones.

J Agric Food Chem, 2000 Jun, 48(6), 2253 - 9
Solid phase microextraction/gas chromatography of Salmonella-infected beef; Ogihara H et al.; Eight strains of Salmonellae were incubated in TSB culture medium at 37 degrees C for 24 h . Volatile compounds derived from the bacteria were collected using solid-phase microextraction fibers and then applied to gas chromatography (GC) . Similarity analysis of the GC patterns thus obtained could separate these strains on principal component similarity (PCS) scattergrams . Five major food-related pathogenic bacteria and 10 other bacteria (including one Salmonella strain) were also classified by growing in the same medium . It is then proposed to utilize this approach to improve the GC/PCS method of Nakai et al . {Nakai, S.; Wang, Z . H.; Dou, J.; Nakamura, S.; Ogawa, M.; Nakai, E.; Vangerstoep, J . J . Agric . Food Chem . 1999, 47, 576-583} that has been developed for screening safe foods by detecting bacteria contaminated foods . Inoculating food samples pre-enriched through preliminary incubation into a culture medium and then subjecting to the GC/PCS method after secondary incubation enhances the detectability of pathogenic bacteria.

JPEN J Parenter Enteral Nutr, 2000 Jul-Aug, 24(4), 215 - 22
Effect of alanyl-glutamine on leucine and protein metabolism in endotoxemic rats; Holecek M et al.; BACKGROUND: Branched-chain amino acids (BCAA; valine, leucine, and isoleucine) have a regulatory effect on protein metabolism and are the main donor for synthesis of alanine and glutamine in the skeletal muscle . This study was performed to investigate whether exogenous alanine or glutamine would affect leucine and protein metabolism in intact and endotoxemic rats . METHODS: Rats were injected with endotoxin of Salmonella enteritidis or saline . Thirty minutes later, the effects of endotoxemia and L-alanyl-L-glutamine (AG) on leucine and protein metabolism were evaluated using a primed constant infusion of {1-14C}leucine, endotoxin, and AG (200 mg/mL) solution or an infusion of {1-14C}leucine without endotoxin or AG . The specificity of the effect of exogenous alanine and glutamine was evaluated by a single infusion of alanine, glutamine, and glycine in a separate study . RESULTS: Endotoxin treatment induced more negative net protein balance caused mainly by an increase in whole-body proteolysis . Protein synthesis increased in kidneys, colon, and spleen, while a decrease was observed in skeletal muscle . The impressive effects of AG were the decrease in plasma branched-chain amino acid (BCAA) levels, decrease in leucine oxidized fraction, and improvement of protein balance associated with a decrease in whole-body proteolysis . Similar changes in leucine and protein metabolism were induced by infusion of alanine or glutamine but not by infusion of glycine . CONCLUSIONS: IV administration of alanine or glutamine improves protein balance and decreases leucine oxidized fraction in postabsorptive state and in endotoxemia . Decreased proteolysis is the main cause of decreased plasma BCAA levels after AG treatment.

J Zoo Wildl Med, 2000 Mar, 31(1), 20 - 7
Proliferative osteoarthritis and osteoarthrosis in 15 snakes; Isaza R et al.; Fifteen snakes representing seven species with segmental, proliferative osteoarthritis and osteoarthrosis of the spine were presented for examination . All the snakes were captive, privately owned, and fed domestic rodents . Physical examination, radiography, blood culture, bone culture, necropsy, and histopathology were performed on each snake . All the snakes had similar physical examination, radiologic, and necropsy findings . There were three histologic types of lesions: active bacterial osteoarthritis, predominantly noninflammatory osteoarthrosis with multifocal inflammation suggestive of chronic bacterial osteoarthritis, and noninflammatory lesions consistent with osteoarthrosis without evidence of inflammation or bacteria . These findings suggest that all these snakes represent a single disease process, bacterial infection of the vertebrae . The different histologic lesions observed in these snakes may be a continuum of lesions, from acute to chronic . Gram-negative bacteria were isolated from the blood or bone lesions of 8 of the 15 snakes . In six of these eight snakes, Salmonella species were isolated . Gram-positive bacteria (Streptococcus sp.) were isolated from two other snakes . Blood and bone culture results were well correlated, so blood culture may be effective for detecting active bacterial osteoarthritis.

Avian Dis, 2000 Apr-Jun, 44(2), 470 - 8
Severe leukopenia and liver necrosis in young African grey parrots (Psittacus erithacus erithacus) infected with psittacine circovirus; Schoemaker NJ et al.; This paper describes the signs, clinical pathology, and postmortem findings in 14 young African grey parrots (Psittacus erithacus erithacus) that were naturally infected with psittacine beak and feather disease (PBFD) virus (psittacine circovirus) . All but two of the parrots had severe leukopenia at clinical presentation . Two other parrots also had severe anemia . All birds died within 3 wk after presentation . Postmortem examination documented liver necrosis in 11 of 14 birds and secondary bacterial or fungal infections in 9 of 14 birds . Tests for Chlamydia psittaci, polyomavirus, and Salmonella sp . were negative . PBFD viral infection could be demonstrated in all birds by polymerase chain reaction . Supporting evidence of PBFD viral infection was gathered by histologic examination of the bursa of Fabricius, electron microscopy, and DNA in situ hybridization . Electron microscopic examination of both the bursa of Fabricius and liver revealed virus particles resembling circovirus . DNA in situ hybridization of six liver tissue samples confirmed the presence of PBFD virus and excluded the presence of avian polyomavirus . Our findings suggest that a specific presentation of peracute PBFD viral infection, characterized by severe leukopenia, anemia, or pancytopenia and liver necrosis in the absence of feather and beak abnormalities, may occur in young African grey parrots.

Avian Dis, 2000 Apr-Jun, 44(2), 291 - 6
Establishment of an enzyme-linked immunosorbent assay with a coated deflagellated Salmonella enteritidis antigen for detection of a specific chicken antibody; Yamane Y et al.; We attempted to establish an enzyme-linked immunosorbent assay (ELISA) for field monitoring/profiling purposes for Salmonella enteritidis (SE) infection of poultry flocks . Serotyping rabbit sera, commercially obtained, specific for Salmonella identification sera to O2, O4, O7, O8, S . Vi, S . Hm, and O9, showed negative ELISA (E)-values (< 0.2) on ELISA, except the O9 identification serum (E-value > 0.5) . Similar negative E-value results were obtained for antisera to Echerichia coli (E . O antigen) . Field serum samples originating from SE-isolated flocks yielded similar positive ratios on both ELISAs including the present coated deflagellated SE antigen and a commercially obtained flagellated SE antigen and that of rapid plate aggregation with a pullorum antigen (PD-RPA) . About 100 days after the first monitoring, no SE isolation in the same flock was observed resulting in a carrier state of SE infection . Although both the monitoring results with commercially obtained ELISA and PD-RPA showed lower positive or negative ratios, the present ELISA showed a higher positive ratio than that of the first monitoring . The present ELISA is suggested to be a suitable method to do accurate profiling on the carrier state of infection.

Avian Dis, 2000 Apr-Jun, 44(2), 249 - 55
Results of a Salmonella enteritidis vaccination field trial in broiler-breeder flocks in The Netherlands; Feberwee A et al.; From August 1995 until December 1997, the effect of adding Salmonella enteritidis (SE) vaccination to a certified standardized biosecurity program in a situation of increased infection risk was examined in a field trial in The Netherlands . In this field trial, two groups of broiler-breeder flocks with increased infection risk were vaccinated, one group with VAC-T/TALOVAC logSE(group A) and the second group with SALENVAC (group B) . The determination of increased infection risk in groups A and B was based on an SE infection history; flocks were either previously infected and treated (PIT) or had other risk factors than previously infected and treated (OPIT) . SE infections in both vaccinated groups were assessed by monitoring according to the Dutch salmonella control program . Under field conditions, designation of a vaccinated and a control group on the farm was not possible . In the same period as the vaccinated groups, 608 nonvaccinated flocks (group C) were hatched and monitored according to the Dutch salmonella control program . The flock level occurrence of SE infection in the vaccinated groups was compared with the flock level occurrence of SE infection in the nonvaccinated group on the basis of comparability of infection risk . In group C, whether or not flocks had infection risk PIT was known and for risk factor OPIT, only whether or not a flock had been placed on a previously contaminated farm (= risk of reinfection) was known . The proportion of SE-infected flocks with risk factor PIT in the vaccinated groups was not significantly different from that in the nonvaccinated group C . Only the proportion of SE-infected flocks with a risk of reinfection in the vaccinated group B (0) was significantly lower (P = 0.02) than in the nonvaccinated group C (18%) . The fact that no significant result was found in favor of group A is because of the small number of flocks in this part of the study . On the basis of the conditions of the setup of this trial, it can only be concluded that there is an indication that vaccination contributes in the reduction of SE reinfection in broiler breeder flocks.

Zh Mikrobiol Epidemiol Immunobiol, 2000 Jan-Feb, (1), 24 - 7
{The criterion of cell division synchronization for assessing the stressor exposure of a Salmonella typhi population}; Druzhinin OG et al.; Criterion of the synchronization (CS) of cells division for S . typhi population is proposed . The criterion is based on the assumption of the normal distribution of cells with different generation time in the population after stressor (shock) action . CS is equal to the ratio of the dispersion of the generation time of cells in the population to the average generation time of the whole population and determined from the parameters of the mathematical model . The quantitative values of the parameters of the mathematical model were obtained by the minimization of error between the calculation and experimental data . CS was used for the evaluation and choice of the optimum stressor action in the synchronization of the division of S . typhi.

Zh Mikrobiol Epidemiol Immunobiol, 2000 Jan-Feb, (1), 6 - 10
{The interaction of Yersinia, Listeria and Salmonella with plant cells}; Timchenbko NF et al.; The results of the interaction of bacteria of the genera Yersinia, Listeria and Salmonella, pathogenic for humans and animals, with callus cultures of different plant species are presented . As revealed in this study, complicated interactions developed between bacteria and plant cells . Plant cells were shown to be highly sensitive to the action of bacteria . Yersinia, Listeria and Salmonella were found to be capable of callus damage . The influence of plant cells on bacteria was more complicated: both the stimulation of bacterial growth and its inhibition were noted, depending on the time of cultivation.

Int J Biometeorol, 2000 May, 44(1), 31 - 43
Thermoregulation in complex situations: combined heat exposure, infectious fever and water deprivation; Blatteis CM; Heat exposure, infectious fever and water deprivation are stressors that, individually, produce disturbances in more than one regulated system, calling for diverse compensatory responses . A potential conflict is created when these stimuli are combined and impose concurrent stressful loads on the body because the homeostatic defenses mobilized against one are also partly needed against the other stressors . To learn how the competing demands of combined stressors for shared regulatory systems are met, rabbits were exposed to 32 degrees C and 37 degrees C (heat), administered lipopolysaccharide (Salmonella enteritidis LPS, 2 lg/kg, i.v.) in temperatures of 22 degrees C or 27 degrees C, or water-deprived for 1 or 2 days in 22 degrees C or 27 degrees C, in separate experiments . The corresponding controls were exposed to 22 degrees C or 27 degrees C, administered pyrogen-free saline i.v . in 22 degrees C or 27 degrees C, or normally hydrated in 22 degrees C or 27 degrees C . In subsequent experiments, two or all three of these treatments were applied concurrently . Core and ear skin temperatures and respiratory rates were monitored continuously . The results indicated that the concomitant needs of moderate heat exposure, fever and 1 day of water deprivation were generally met by the regulatory systems involved, but different patterns of thermoeffector activities were evoked and the eventual body temperature changes produced were different under each condition . However, when the test conditions were severe, their combined needs were not met adequately and the eventual compensatory response depended not only on the particular stimulus intensity, but also on the immediate importance for survival of the functions being defended . Thus, dehydration was the most dangerous factor to the physiological integrity of the animals . In sum, conflicting physiological stimuli appear to result in responses that are different from the responses to a single perturbation, the eventual output representing the resultant of the inputs rather than a singular output dictated by one dominant drive to the exclusion of the others.

Rev Esp Quimioter, 1999, 12(4), 366 - 368
{Evolution of resistance to quinolonesin Salmonella enterica in our environment}; Ruiz M et al.; Salmonella enterica is mainly associated with acute gastroenteritis; however, it is also associated with other more severe disease processes, for which quinolones are the treatment of choice . We retrospectively studied the evolution of resistance to nalidixic acid and ciprofloxacin of all the clinical isolates of S . enterica from 1992 to 1998 in our hospital environment . A total of 848 strains from feces, blood and other locations were studied . We detected an increase in the resistance to nalidixic acid from 12% in 1992 to 21.3% in 1998, especially in the Enteritidis and Hadar serotypes . We did not detect resistance to ciprofloxacin, but there was in increase in the MIC in the nalidixic acid-resistant strains . Although this is interpreted as sensitive according the the NCCLS criteria, if we apply the cutoff points established by MENSURA, 89.46% of the strains do not fit into this category (S <0.12 mg/l) . This puts into question the utility of quinolones in the long-term treatment of severe disease processes produced by this type of strain.

Philos Trans R Soc Lond B Biol Sci, 2000 May 29, 355(1397), 681 - 93
Type III secretion: a bacterial device for close combat with cells of their eukaryotic host; Cornelis GR; Salmonella, Shigella, Yersinia, Pseudomonas aeruginosa, enteropathogenic Escherichia coli and several plant-pathogenic Gram-negative bacteria use a new type of systems called 'type III secretion' to attack their host . These systems are activated by contact with a eukaryotic cell membrane and they allow bacteria to inject bacterial proteins across the two bacterial membranes and the eukaryotic cell membrane to reach a given compartment and destroy or subvert the target cell . These systems consist of a secretion apparatus made up of about 25 individual proteins and a set of proteins released by this apparatus . Some of these released proteins are 'effectors' that are delivered by extracellular bacteria into the cytosol of the target cell while the others are 'translocators' that help the 'effectors' to cross the membrane of the eukaryotic cell . Most of the 'effectors' act on the cytoskeleton or on intracellular signalling cascades . One of the proteins injected by the enteropathogenic E . coli serves as a membrane receptor for the docking of the bacterium itself at the surface of the cell.

J Mol Biol, 2000 Jul 7, 300(2), 291 - 305
Acetyl phosphate-dependent activation of a mutant PhoP response regulator that functions independently of its cognate sensor kinase; Chamnongpol S et al.; The two-component system is a signal communication network generally consisting of a sensor kinase that receives inputs from the environment and modifies the phosphorylated state of a response regulator that executes an adaptive behavior . PhoP is a response regulator that controls virulence gene expression in Salmonella enterica . Transcription of PhoP-regulated genes is modulated by the Mg(2+) levels detected by the sensor PhoQ . Here, we describe a PhoP mutant protein, PhoP*, that functions in the absence of its cognate sensor, thereby allowing transcription of PhoP-activated genes independently of the Mg(2+ )concentration in the environment . The PhoP* protein harbors a S93N substitution in the response regulator receiver domain . PhoP*-mediated transcription is abolished by either mutation of the aspartate residue that is conserved among response regulators as the site of phosphorylation or inactivation of the pta-encoded phosphotransacetylase . This enzyme mediates the production of acetyl phosphate, which has been shown to serve as a low molecular mass phosphate donor for certain response regulators . The purified PhoP* protein autophosphorylated from acetyl phosphate more efficiently than the wild-type PhoP protein in vitro . The PhoP* protein retained the capacity to interact with the PhoQ protein, which promoted phosphorylation of the PhoP* protein in vitro and abolished PhoP*-mediated transcription under high Mg(2+ )concentrations in vivo . Cumulatively, our results uncover a role of PhoQ in transcriptional repression during growth in millimolar Mg(2+ )and define a mutant response regulator form with an increased capacity to be phosphorylated by acetyl phosphate .

Cell Immunol, 2000 May 25, 202(1), 61 - 9
gammadelta T cells may dichotomously modulate infection with avirulent Salmonella choleraesuis via IFN-gamma and IL-13 in mice; Naiki Y et al.; To investigate the roles of gammadelta T cells in Salmonella infection, we examined the resolution of an intraperitoneal infection with avirulent Salmonella choleraesuis 31N-1 in mice lacking T-cell-receptor (TCR) alphabeta T cells by disruption of the TCRbeta chain gene (TCRbeta(-/-)) . The bacteria in TCRbeta(-/-) mice decreased with kinetics similar to that seen in control mice (TCRbeta(+/+)) after infection . The number of natural killer (NK) cells in the peritoneal cavity increased on day 6 after infection and thereafter decreased in both TCRbeta(-/-) and TCRbeta(+/+) mice, whereas the number of gammadelta T cells, in place of alphabeta T cells, increased remarkably in the peritoneal cavity of TCRbeta(-/-) mice on day 6 after infection . The NK cells from Salmonella-infected TCRbeta(-/-) mice produced interferon-gamma (IFN-gamma) but neither interleukin-4 (IL-4) nor IL-13 in response to immobilized anti-NK1.1 monoclonal antibody (mAb) . The gammadelta T cells produced IFN-gamma but neither IL-4 nor IL-13 in response to heat-killed Salmonella, whereas both IFN-gamma and IL-13 but no IL-4 was produced by the gammadelta T cells stimulated with immobilized anti-TCRgammadelta mAb . In vivo administration of anti-NK1.1 mAb inhibited the reduction of Salmonella, whereas anti-TCRgammadelta mAb treatment did not affect the bacterial growth in TCRbeta(-/-) mice after Salmonella infection . However, neutralization of endogenous IL-13 with anti-IL-13 mAb enhanced the bacterial clearance in TCRbeta(-/-) mice after infection . These results suggest that NK1.1(+) cells serve mainly to protect against avirulent Salmonella infection in the absence of alphabeta T cells, whereas gammadelta T cells may play dichotomous roles in Salmonella infection through IFN-gamma and IL-13 in TCRbeta(-/-) mice .

Biochem Biophys Res Commun, 2000 May 27, 272(1), 6 - 11
Characterization of large plasmids encoding resistance to toxic heavy metals in Salmonella abortus equi; Ghosh A et al.; Salmonella abortus equi vaccine strains were found to be resistant to high levels of toxic heavy metals--arsenic, chromium, cadmium, and mercury . The two strains 157 and 158 were resistant to ampicillin also . Curing of these strains resulted in loss of one or more resistance marker indicating plasmid borne resistance . Plasmid profile of strain 157 showed presence of three plasmids of 85, 54, and 0.1 Kb, whereas 158 strain showed presence of 85 Kb and 2 Kb plasmids . Plasmids were isolated from strain 157 and introduced into E . coli DH5alpha with a transformation efficiency of 2 x 10(3) transformants/microg DNA . Interestingly the transformants were resistant to antibiotics, heavy metals (As, Cr, Cd, Hg) and was also able to utilize citrate, a trait specific to Salmonella species . We report and establish for the first time the transferable large plasmids encoding resistance to various heavy metals, antibiotics and biochemical nature of S . abortus equi.

Vaccine, 2000 Aug 1, 18(28), 3208 - 13
A comparison of immunogenicity and in vivo distribution of Salmonella enterica serovar Typhi and Typhimurium live vector vaccines delivered by mucosal routes in the murine model; Pasetti MF et al.; We evaluated the immune responses elicited by attenuated Salmonella enterica serovar Typhi vaccine strain CVD 908-htrA and serovar Typhimurium strain SL3261 alone or as live vectors carrying a plasmid encoding fragment C of tetanus toxin (pTETnir15) in mice immunized intranasally and orogastrically, as well as the in vivo distribution of vaccine organisms following immunization . Higher serologic and proliferative responses against both vector and the foreign antigen were elicited when vaccines were delivered by intranasal route . Whereas both Salmonella strains were detected in the nasal tissue, lungs, and Peyer's patches following intranasal and orogastric immunization, larger numbers of vaccine organisms were recovered from these tissues when the vaccines were delivered intranasally.

J Pharmacol Exp Ther, 2000 Jun, 293(3), 968 - 72
Oxidant stress in rat liver after lipopolysaccharide administration: effect of inducible nitric-oxide synthase inhibition; Zhang C et al.; The role of inducible nitric-oxide synthase (iNOS) in lipopolysaccharide (LPS)-induced hepatic oxidant stress was evaluated using the iNOS inhibitor L-iminoethyl-lysine (L-NIL) . Male rats were divided into three groups . One group received LPS (Salmonella minnesota) 2 mg/kg i.v . A second group received LPS plus L-NIL (3 mg/kg i.p.) at the time of LPS administration followed by a second dose 3 h later . A third group received saline i.v . At 6 h, blood and liver tissue were collected . Serum nitrate/nitrite (metabolic products of nitric oxide) levels were increased from 5.4 +/- 1.5 nmol/ml in the saline group to 360 +/- 48 nmol/ml in the LPS group (n = 5) . Values for the LPS + L-NIL group were significantly reduced to 35 +/- 7 nmol/ml . Tissue malondialdehyde levels were increased from 0.20 +/- 0.02 nmol/mg (n = 4) in the saline group to 0.41 +/- 0.03 nmol/mg (n = 4) in the LPS group . L-NIL significantly reduced the values in the LPS group to 0.29 +/- 0.02 nmol/mg (n = 4) . 4-Hydroxynonenal-protein adducts levels were increased 3.6-fold by LPS treatment as compared with saline . L-NIL significantly reversed the levels to 1.6-fold (n = 4) . Intracellular GSH levels were decreased from 8.49 +/- 0.64 nmol/mg (n = 4) in the saline group to 5.63 +/- 0.51 nmol/mg in the LPS group (n = 7) . L-NIL significantly increased the levels in the LPS group to 7.04 +/- 0.46 nmol/mg (n = 7) . These data indicate that LPS-induced nitric oxide generation can result in oxidant stress in the liver, and that inhibitors of iNOS may offer some protection in LPS-induced hepatic toxicity.

J Bacteriol, 2000 Jul, 182(14), 4077 - 86
A PhoP-regulated outer membrane protease of Salmonella enterica serovar typhimurium promotes resistance to alpha-helical antimicrobial peptides; Guina T et al.; The outer membrane protein contents of Salmonella enterica serovar Typhimurium strains with PhoP/PhoQ regulon mutations were compared by two-dimensional gel electrophoresis . At least 26 species of outer membrane proteins (OMPs) were identified as being regulated by PhoP/PhoQ activation . One PhoP/PhoQ-activated OMP was identified by semiautomated tandem mass spectrometry coupled with electronic database searching as PgtE, a member of the Escherichia coli OmpT and Yersinia pestis Pla family of outer membrane proteases . Salmonella PgtE expression promoted resistance to alpha-helical cationic antimicrobial peptides (alpha-CAMPs) . Strains expressing PgtE cleaved C18G, an 18-residue alpha-CAMP present in culture medium, indicating that protease activity is likely to be the mechanism of OmpT-mediated resistance to alpha-CAMPs . PhoP/PhoQ did not regulate the transcription or export of PgtE, indicating that another PhoP/PhoQ-dependent mechanism is required for PgtE outer membrane localization . PgtE is a posttranscriptionally regulated component of the PhoP/PhoQ regulon that contributes to Salmonella resistance to innate immunity.

J Bacteriol, 2000 Jul, 182(14), 4044 - 50
The flagellar hook protein, FlgE, of Salmonella enterica serovar typhimurium is posttranscriptionally regulated in response to the stage of flagellar assembly; Bonifield HR et al.; We investigated the posttranscriptional regulation of flgE, a class 2 gene that encodes the hook subunit protein of the flagella . RNase protection assays demonstrated that the flgE gene was transcribed at comparable levels in numerous strains defective in known steps of flagellar assembly . However, Western analyses of these strains demonstrated substantial differences in FlgE protein levels . Although wild-type FlgE levels were observed in strains with deletions of genes encoding components of the switch complex and the flagellum-specific secretion apparatus, no protein was detected in a strain with deletions of the rod, ring, and hook-associated proteins . To determine whether FlgE levels were affected by the stage of hook-basal-body assembly, Western analysis was performed on strains with mutations at individual loci encompassed by the deletion . FlgE protein was undetectable in rod mutants, intermediate in ring mutants, and wild type in hook-associated protein mutants . The lack of negative regulation in switch complex and flagellum-specific secretion apparatus deletion mutants blocked for flagellar construction prior to rod assembly suggests that these structures play a role in the negative regulation of FlgE . Quantitative Western analyses of numerous flagellar mutants indicate that FlgE levels reflect the stage at which flagellar assembly is blocked . These data provide evidence for negative posttranscriptional regulation of FlgE in response to the stage of flagellar assembly.

J Bacteriol, 2000 Jul, 182(14), 3896 - 903
Metabolic defects caused by mutations in the isc gene cluster in Salmonella enterica serovar typhimurium: implications for thiamine synthesis; Skovran E et al.; The metabolic consequences of two insertions, iscR1::MudJ and iscA2::MudJ, in the isc gene cluster of Salmonella enterica serovar Typhimurium were studied . Each of these insertions had polar effects and caused a nutritional requirement for the thiazole moiety of thiamine . Data showed that IscS was required for the synthesis of nicotinic acid and the thiazole moiety of thiamine and that one or more additional isc gene products were required for a distinct step in the thiazole biosynthetic pathway . Strains with isc lesions had reduced succinate dehydrogenase and aconitase activities . Furthermore, isc mutants accumulated increased levels of pyruvate in the growth medium in response to exogenously added iron (FeCl(3)), and this response required a functional ferric uptake regulator, Fur.

Microb Drug Resist, 2000 Spring, 6(1), 77 - 83
Origins and consequences of antimicrobial-resistant nontyphoidal Salmonella: implications for the use of fluoroquinolones in food animals; Angulo FJ et al.; Human Salmonella infections are common; most infections are self-limiting, however severe disease may occur . Antimicrobial agents, while not essential for the treatment of Salmonella gastroenteritis, are essential for the treatment of thousands of patients each year with invasive infections . Fluoroquinolones and third-generation cephalosporins are the drugs-of-choice for invasive Salmonella infections in humans; alternative antimicrobial choices are limited by increasing antimicrobial resistance, limited efficacy, and less desirable pharmacodynamic properties . Antimicrobial-resistant Salmonella results from the use of antimicrobial agents in food animals, and these antimicrobial resistant Salmonella are subsequently transmitted to humans, usually through the food supply . The antimicrobial resistance patterns of isolates collected from persons with Salmonella infections show more resistance to antimicrobial agents used in agriculture than to antimicrobial agents used for the treatment of Salmonella infections in humans . Because of the adverse health consequences in humans and animals associated with the increasing prevalence of antimicrobial-resistant Salmonella, there is an urgent need to emphasize non-antimicrobial infection control strategies, such as improved sanitation and hygiene, to develop guidelines for the prudent usage of antimicrobial agents, and establishment of adequate public health safeguards to minimize the development and dissemination of antimicrobial resistance and dissemination of Salmonella resistant to these agents.

Microb Drug Resist, 2000 Spring, 6(1), 11 - 7
Quinolone resistance among Salmonella enterica from cattle, broilers, and swine in Denmark; Wiuff C et al.; This study was conducted to determine the susceptibility to nalidixic acid and fluoroquinolones of Salmonella Dublin, S . Enteritidis, and S . Typhimurium isolates from cattle, broilers, and pigs over time in Denmark and to characterise the gyrA, gyrB, and parC genes in quinolone-resistant isolates . A total of 584 S . Typhimiurium and 573 S . Dublin isolates from cattle during 1984 through 1999, and 241 S . Enteritidis and 131 S . Typhimurium from broilers and 452 S . Typhimurium from pigs isolated during 1997-1999 were tested . All isolates from cattle from the period 1984 through 1992 were susceptible to quinolones . A single (1.1%) S . Typhimurium isolate from 1995 and three (5.9%) from 1998 were resistant to nalidixic acid . Six (9.0%) S . Dublin isolates from 1996, four (4.2%) from 1997, and one (1.7%) from 1998 were resistant to nalidixic acid . Resistance was not observed among isolates from cattle in 1999 . All broiler isolates from 1997 except for one were susceptible to nalidixic acid, whereas seven (6.2%) S . Enteritidis and two (6.3%) of the S . Typhimurium isolates from 1998 and 9 S . Enteritidis (26.5%) from 1999 were resistant . Among isolates from pigs, four isolates from 1997, three from 1998, and one from 1999 were resistant to nalidixic acid . All the nalidixic acid-resistant isolates had reduced susceptibility to fluoroquinolones . Sequence analysis of the gyrA gene in 37 nalidixic-resistant isolates identified two different base substitutions at codon serine-83 and two at aspartate-87 . The base substitutions in serine-83 were TCC (Ser)-->TAC (Tyr), and TCC (Ser)-->TTC (Phe) . The base substitutions in aspartic-87 were GAC (Asp)-->AAC (Asn), and GAC (Asp)-->GGC (Gly) . Sequence analysis of the gyrB and parC genes revealed no mutations in 27 selected isolates . This study showed that quinolone-resistant isolates have emerged in recent years among food-producing animals, especially among S . Enteritidis from broilers in Denmark, and that the resistance mainly is associated with mutations in gyrA.

Int J Food Microbiol, 2000 Jun 15, 57(3), 159 - 67
Growth of Salmonella choleraesuis subspecies diarizonae serovar 61:k:1,5,(7) in broth and fresh mutton; Alvseike O et al.; Three serovars of Salmonella choleraesuis (IIIb 61:k:1,5,(7), Enteritidis and Dublin) were grown in broths of pH 5.5 and 6.2 and incubated at 4, 6, 8 or 12 degrees C . Growth in the broth, measured by means of an increase of absorbance, was not observed below 8 degrees C . At 8 and 12 degrees C, the maximum growth rate (mu(max)), lag period and maximum absorbance level (max(abs)) varied according to serovar and pH . In general, serovar IIIb 61:k:1,5,(7) and serovar Enteritidis grew better than serovar Dublin . The effect of pH on lag period, seen for serovar IIIb 61:k:1,5,(7) and serovar Enteritidis at 8 degrees C, was absent at 12 degrees C, while the effect of pH regarding the mu(max) and the max(abs) was observed also at 12 degrees C . Furthermore, the growth serovar IIIb 61:k:1,5,(7) in normal and dark, firm and dry meat at 8 degrees C with ambient air in competition with the natural microbial flora was tested in minced meat and chops . Slow growth of serovar IIIb 61:k:1,5,(7) was observed in minced meat . The low virulence and the ordinary growth capabilities indicate that serovar IIIb 61:k:1,5,(7) will probably not represent a serious hazard to the public health.

Turk J Pediatr, 1997 Jan-Mar, 39(1), 7 - 11
Antibiotic susceptibilities of Salmonella serogroups isolated from Turkish children; Akan O et al.; This study is performed to show the serogroup distribution and in-vitro antibiotic susceptibilities of Salmonella species that cause either gastroenteritis with/without bacteremia or enteric fever at Hacettepe University Ihsan Dogramaci Children's Hospital . Of the 309 Salmonella strains evaluated, serogroup B was the most common isolate (56%) followed by serogroup D (33%) . Antibiotic susceptibility tests using the disk diffusion technique revealed resistance rates of 43 percent for ampicillin, 41 percent for chloramphenicol, 29 percent for trimethoprim-sulfamethoxazole (SXT) and 32 percent for ceftriaxone among Salmonella serogroup B . The same rates were 10, eight, seven and zero percent for Salmonella serogroup D, and seven, 14, and zero percent for serogroup C, respectively . S.thypi strains susceptible to all antibiotics studied except tetracycline (33% resistant) . No resistance was detected against the quinolones . The antibiotic resistance of Salmonella species isolated from children seems to be important, especially in serogroup B . Susceptibility tests should be considered in the antimicrobial therapy of Salmonella infections where indicated.

FEMS Microbiol Lett, 2000 Jul 1, 188(1), 15 - 8
Role of the Salmonella abortusovis virulence plasmid in the infection of BALB/c mice; Uzzau S et al.; Following oral inoculation of BALB/c mice, Salmonella abortusovis strain SS44 was recovered in lower numbers from the Peyer's patches and mesenteric lymph nodes compared with S . typhimurium strain SL1344, whereas splenic infections were equivalent between the two serovars . SS44 was cured of its virulence plasmid or subjected to mutagenesis of the spv genes, and the Spv(-) derivatives were tested for virulence in mice . Plasmid-cured S . abortusovis SU40 retained virulence in BALB/c mice when inoculated intraperitoneally . On the other hand, mice infected orally with SU40 had greatly reduced splenic infection compared to those infected with wild-type SS44 . Similar results were obtained after Tn5 insertion mutagenesis of the spvR gene or deletion of the spvABCD locus . These results suggest that in the gut-associated lymphoid tissues S . abortusovis may replicate less than S . typhimurium and that the S . abortusovis virulence plasmid primarily affects systemic infection after oral inoculation but not after intraperitoneal administration in the mouse model.

Res Microbiol, 2000 Apr, 151(3), 183 - 9
Virulence characterization of a strain of Salmonella enterica subspecies houten (subspecies IV) with chromosomal integrated Salmonella plasmid virulence (spv) genes; Aabo S et al.; The Salmonella plasmid virulence genes (spv) are commonly found on plasmids contained in a small number of serotypes of Salmonella belonging to subspecies I, where they are important for survival within macrophages and the establishment of successful systemic infection . However, in this study, spv genes were detected by the polymerase chain reaction in the chromosome of a plasmid-free strain of S . IV 16:z4, z32:- (Salmonella subspecies IV) . The full range of spv genes (spvR, spvA, spvB, spvC and spvD) was demonstrated, but a 216-bp deletion, accompanied by an insertion of 59-bp cryptic DNA, was present in spvA . S . IV 16:z4, z32:- was avirulent in mice and did not become virulent with the introduction of a fully functionally serotype-associated virulence plasmid (SAP) from S . typhimurium . By use of an spvRAB'-chloramphenicol acetyl transferase fusion gene, it was demonstrated that S . IV 16:z4, z32:- did not express the spv genes . Salmonella subspecies IV is monophasic, and in phylogenetic analyses it clusters distantly to Salmonella subspecies I, where all the serotypes that normally carry SAPs are found . The mechanisms by which spv genes have been transferred to this serotype remain unknown.

Med Dosw Mikrobiol, 1999, 51(1-2), 73 - 9
{Bacteriophage types of Salmonella enteritidis occurring in Poland in 1986-1995}; Dera-Tomaszewska B et al.; The Lalko phages collection was used to phage type a total of 517 Salmonella Enteritidis strains isolated from food-poisoning outbreaks (312 strains) and other common sources (205 strains) in Poland, during the years 1986-1995 . Above 99.0% of all strains tested were recognized as belonging to definitive phage type . Phage types 1, 6 and 7 were predominant . The strains of type 1 and 7 were most numerous . Of the 517 examined strains 312 were isolated from 46 food-poisoning outbreaks . Most of them came from the one phage type outbreaks; 8 mixed outbreaks were noted . The greatest number of the food-poisoning outbreaks was caused by Salmonella Enteritidis phage types 1, 6 and 7 . Phage type 16 was isolated from persons for the first time.

Mutat Res, 2000 Jun 22, 468(1), 19 - 25
In vivo genotoxicity of 2-amino-3,8-dimethylimidazo{4, 5-f}quinoxaline in lacI transgenic (Big Blue) mice; Itoh1 T et al.; 2-Amino-3,8-dimethylimidazo{4,5-f}quinoxaline (MeIQx), a heterocyclic amine found in cooked meat, is a strong mutagen in the Salmonella/microsome assay and was proven to be a hepatocarcinogen in rodents . We used the lacI transgenic (Big Blue(R)) mouse to investigate MeIQx genotoxicity in vivo . lacI mutant frequencies were examined in liver and colon after single intragastric administration of MeIQx (males) or 12 weeks of feeding in the diet (males and females) . Micronucleus induction was monitored in the peripheral blood and cell proliferating activity was monitored by proliferating cell nuclear antigen (PCNA) immunostaining, but only after the intragastric administration . Intragastric treatment with MeIQx (100 mg/kg) did not increase mutant frequency (MF) in liver or colon but it did induce a slight but statistically significant increase in the incidence of micronucleated reticulocytes 48 h after the treatment . No apparent increase in PCNA-positive foci was observed in any of tissues analyzed 14 days after the treatment . Administration of MeIQx (300 ppm) in diet for 12 weeks, however, caused MF increases in liver and colon in male and female mice, with greater increases in the females . An increase was also obvious after 4 weeks, but only in females . The sex difference in MF is consistent with the fact that female mice are more susceptible to MeIQx carcinogenesis . These results demonstrated that in the transgenic mouse mutation assay, long-term feeding of MeIQx was more effective than single gastric exposures in revealing the compound's mutagenicity in the target organs of carcinogenicity and that sex differences in susceptibility can also be observed.

Indian J Med Sci, 1999 Nov, 53(11), 486 - 9
Drug resistance pattern and phage types of Salmonella typhi isolates in Manipal, South Karnataka; Ciraj AM et al.; Out of the 226 strains of S . typhi isolated over a period of three years 57.9% of them were multidrug resistant . 8.8% of the isolates were sensitive to all the drugs tested . A significant decline in hte number of multidrug resistant strains was observed in this region . Majority of the isolates belonged to phage type E (75.7%) and Biotype 1 (93.8%) . All strains isolated were sensitive to ciprofloxacin, norfloxacin and ceftriaxone.

Environ Mol Mutagen, 2000, 35(4), 279 - 99
Quantitative structure-activity relationship of flavonoids for inhibition of heterocyclic amine mutagenicity; Hatch FT et al.; The mutagenic/carcinogenic heterocyclic amines formed during the cooking of protein foods have been determined to be a potential risk to human health . Therefore, mitigation measures are beginning to be studied . A recent finding is that the induction of mutation in Salmonella by these amines can be inhibited by the addition of flavonoids to the assay . This study combines data on the inhibitory process with structural, ab initio quantum chemical, hydropathic, and antioxidant factors to develop a quantitative structure-activity relationship (QSAR) database and statistical analysis . For 39 diverse flavonoids the inhibitory potency varied approximately 100-fold . Three predictive variables, in order of decreasing contribution to variance, are: (1) a large dipole moment; (2) after geometric minimization of energy, a small departure from planarity (i.e., small dihedral angle between the benzopyran nucleus and the attached phenyl ring), and a low rotational energy barrier to achieving planarity; and (3) fewer hydroxyl groups on the phenyl ring . However, these variables account for less than half of the variance in inhibitory potency of the flavonoids . Frontier orbital energies and antioxidant or radical scavenging properties showed little or no relationship to potency . We conclude that interference by the flavonoids with cytochrome P450 activation of the promutagens is the probable mechanism for inhibition of mutagenesis, and suggest avenues for further research . Environ . Mol . Mutagen . 35:279-299, 2000 Published 2000 Wiley-Liss, Inc.

Infect Immun, 2000 Jul, 68(7), 4370 - 3
Long-term immunological memory induced by recombinant oral Salmonella vaccine vectors; Kohler JJ et al.; We have previously shown that Salmonella enterica serovar Typhimurium expressing the hagB hemagglutinin gene from Porphyromonas gingivalis can induce primary and recall immune responses in serum and secretions in mice; however, the longevity of memory induced by oral Salmonella carriers has not been adequately demonstrated . In this study, we examined the capacity of mice to mount a recall response 52 weeks after primary immunization . Recall responses were seen in serum immunoglobulin G (IgG) and IgA following boosting at week 52, and in most cases, they were equal to or greater than the primary responses . Significant mucosal IgA recall responses in saliva and vaginal wash were also detected following boosting at week 52 . In addition, there was a considerable residual response in secretions at week 51, prior to boosting . These results indicate that oral Salmonella vectors can induce long-term memory to recombinant HagB and are particularly effective at inducing long-lasting mucosal responses as well as at inducing the capacity for mucosal recall responses.

Infect Immun, 2000 Jul, 68(7), 4349 - 53
Adjuvant activity of a nontoxic mutant of Escherichia coli heat-labile enterotoxin on systemic and mucosal immune responses elicited against a heterologous antigen carried by a live Salmonella enterica serovar Typhimurium vaccine strain; Guillobel HC et al.; Systemic and mucosal antibody responses against both the major subunit of colonization factor antigen I (CFA/I) of enterotoxigenic Escherichia coli (ETEC) and the somatic lipopolysaccharide expressed by recombinant bivalent Salmonella vaccine strains were significantly enhanced by coadministration of a detoxified derivative with preserved adjuvant effects of the ETEC heat-labile toxin, LT((R192G)) . The results further support the adjuvant effects of LT((R192G)) and represent a simple alternative to improve responses against passenger antigens expressed by orally delivered Salmonella vaccine strains.

Infect Immun, 2000 Jul, 68(7), 3793 - 8
Functional analysis of genes in the rfb locus of Leptospira borgpetersenii serovar Hardjo subtype Hardjobovis; Bulach DM et al.; Lipopolysaccharide (LPS) is a key antigen in immunity to leptospirosis . Its biosynthesis requires enzymes for the biosynthesis and polymerization of nucleotide sugars and the transport through and attachment to the bacterial membrane . The genes encoding these functions are commonly clustered into loci; for Leptospira borgpetersenii serovar Hardjo subtype Hardjobovis, this locus, named rfb, spans 36.7 kb and contains 31 open reading frames, of which 28 have been assigned putative functions on the basis of sequence similarity . Characterization of the function of these genes is hindered by the fact that it is not possible to construct isogenic mutant strains in Leptospira . We used two approaches to circumvent this problem . The first was to clone the entire locus into a heterologous host system and determine if a "recombinant" LPS or polysaccharide was synthesized in the new host . The second approach used putative functions to identify mutants in other bacterial species whose mutations might be complemented by genes on the leptospiral rfb locus . This approach was used to investigate the function of three genes in the leptospiral rfb locus and demonstrated function for orfH10, which complemented a wbpM strain of Pseudomonas aeruginosa, and orfH13, which complemented an rfbW strain of Vibrio cholerae . However, despite the similarity of OrfH11 to WecC, a wecC strain of E . coli was not complemented by orfH11 . The predicted protein encoded by orfH8 is similar to GalE from a number of organisms . A Salmonella enterica serovar Typhimurium strain producing no GalE was used as a background in which orfH8 produced detectable GalE enzyme activity.

J Microbiol Methods, 2000 Jun, 41(1), 35 - 43
Genotypic characterization of Salmonella typhi by amplified fragment length polymorphism fingerprinting provides increased discrimination as compared to pulsed-field gel electrophoresis and ribotyping; Nair S et al.; Amplified fragment length polymorphism (AFLP) is a recently developed, PCR-based high resolution fingerprinting method that is able to generate complex banding patterns which can be used to delineate intraspecific genetic relationships among bacteria . In the present study, AFLP was evaluated for its usefulness in the molecular typing of Salmonella typhi in comparison to ribotyping and pulsed-field gel electrophoresis (PFGE) . Six S . typhi isolates from diverse geographic areas (Malaysia, Indonesia, India, Chile, Papua New Guinea and Switzerland) gave unique, heterogeneous profiles when typed by AFLP, a result which was consistent with ribotyping and PFGE analysis . In a further study of selected S . typhi isolates from Papua New Guinea which caused fatal and non-fatal disease previously shown to be clonally related by PFGE, AFLP discriminated between these isolates but did not indicate a linkage between genotype with virulence . We conclude that AFLP (discriminatory index=0.88) has a higher discriminatory power for strain differentiation among S . typhi than ribotyping (DI=0.63) and PFGE (DI=0.74).

Comp Immunol Microbiol Infect Dis, 2000 Jul, 23(3), 175 - 83
Rotavirus and concurrent infections with other enteropathogens in neonatal diarrheic dairy calves in Spain; Garcia A et al.; Faeces samples from 218, one to 30 days old, diarrheic dairy calves in 65 dairy herds were screened for the presence of rotavirus and concurrent infections with coronavirus, Cryptosporidium, F5+ Escherichia coli and Salmonella spp . Calves were grouped according to their age as follows: 1-7, 8-14, 15-21 and 22-30 days . Rotavirus infection was detected in 46.9%, 45.6%, 33.8% and 48.3% of the calves in the respective age-groups . No significant differences in the detection rate of rotavirus were found among calves on the different age-groups . Rotavirus was the only enteropathogen detected in 39 of the 93 (41.9%) diarrheic calves positive to this agent . Concurrent infections with other enteropathogen(s) were detected in 31.3%, 33.3%, 20.6% and 3.4% of the rotavirus infected calves in the age-groups 1-7, 8-14, 15-21 and 22-30 d, respectively . A significant age-associated decrease in the detection rate of mixed infections (p < 0.01) was found . The detection rates of the other enteropathogens considered in calves with rotavirus infection were 20.4% for coronavirus, 85.2% for Cryptosporidium, 16.7% for F5+ E . coli and 1.8% for Salmonella.

Regul Toxicol Pharmacol, 2000 Apr, 31(2 Pt 1), 182 - 9
The high production volume chemical challenge program: the relevance of the in vivo micronucleus assay; Rosenkranz HS et al.; The in vivo rodent bone marrow micronucleus assay (Mnt) has assumed a pivotal role in screening strategies for the identification of substances potentially carcinogenic to humans . The analysis of the results of the current international 5-year effort to provide toxicological data for high production volume chemicals will play a crucial role in developing future strategies for identifying health hazards . As part of that program, consideration is being given to accepting either in vitro genotoxicity data or results of the Mnt . The present analyses indicate that for hazard identification purposes that, in fact, in vitro genotoxicity test results, such as those derived from the Salmonella mutagenicity assay, may be an acceptable alternative.

J Bacteriol, 2000 Jun, 182(12), 3490 - 7
Analysis of the SOS response in Salmonella enterica serovar typhimurium using RNA fingerprinting by arbitrarily primed PCR; Benson NR et al.; We report an analysis of a sample of the SOS response of Salmonella enterica serovar Typhimurium using the differential display of RNA fingerprinting gels of arbitrarily primed PCR products . The SOS response was induced by the addition of mitomycin C to an exponentially growing culture of serovar Typhimurium, and the RNA population was sampled during the following 2 h . These experiments revealed 21 differentially expressed PCR fragments representing mRNA transcripts . These 21 fragments correspond to 20 distinct genes . All of these transcripts were positively regulated, with the observed induction starting 10 to 120 min after addition of mitomycin C . Fifteen of the 21 transcripts have no homologue in the public sequence data banks and are therefore classified as novel . The remaining six transcripts corresponded to the recE, stpA, sulA, and umuC genes, and to a gene encoding a hypothetical protein in the Escherichia coli lysU-cadA intergenic region; the recE gene was represented twice by nonoverlapping fragments . In order to determine if the induction of these 20 transcripts constitutes part of a classical SOS regulon, we assessed the induction of these genes in a recA mutant . With one exception, the increased expression of these genes in response to mitomycin C was dependent on the presence of a functional recA allele . The exception was fivefold induced in the absence of a functional RecA protein, suggesting another layer of regulation in response to mitomycin C, in addition to the RecA-LexA pathway of SOS induction . Our data reveal several genes belonging to operons known to be directly involved in pathogenesis . In addition, we have found several phage-like sequences, some of which may be landmarks of pathogenicity determinants . On the basis of these observations, we propose that the general use of DNA-damaging agents coupled with differential gene expression analysis may be a useful and easy method for identifying pathogenicity determinants in diverse organisms.

J Bacteriol, 2000 Jun, 182(12), 3361 - 7
Hypersensitivity of Escherichia coli Delta(uvrB-bio) mutants to 6-hydroxylaminopurine and other base analogs is due to a defect in molybdenum cofactor biosynthesis; Kozmin SG et al.; We have shown previously that Escherichia coli and Salmonella enterica serovar Typhimurium strains carrying a deletion of the uvrB-bio region are hypersensitive to the mutagenic and toxic action of 6-hydroxylaminopurine (HAP) and related base analogs . This sensitivity is not due to the uvrB excision repair defect associated with this deletion because a uvrB point mutation or a uvrA deficiency does not cause hypersensitivity . In the present work, we have investigated which gene(s) within the deleted region may be responsible for this effect . Using independent approaches, we isolated both a point mutation and a transposon insertion in the moeA gene, which is located in the region covered by the deletion, that conferred HAP sensitivity equal to that conferred by the uvrB-bio deletion . The moeAB operon provides one of a large number of genes responsible for biosynthesis of the molybdenum cofactor . Defects in other genes in the same pathway, such as moa or mod, also lead to the same HAP-hypersensitive phenotype . We propose that the molybdenum cofactor is required as a cofactor for an as yet unidentified enzyme (or enzymes) that acts to inactivate HAP and other related compounds.

J Food Prot, 2000 Jun, 63(6), 779 - 95
Review of studies on the thermal resistance of Salmonellae; Doyle ME et al.; Heat resistance data for different serotypes of Salmonella enterica in different food products and laboratory media are reviewed . From all D-values reported, the highest heat resistance of Salmonella was in liquid eggs and liquid egg yolks . The equation from a line drawn through the highest D-values, and above all values reported, was log D-value = 11.7 - 0.188T degrees C . From this equation, the calculated z-value was 5.3 degrees C (9.5 degrees F), and a process at 71degrees C (160 degrees F) will require 1.2 s to inactivate 1 log of Salmonella cells . This calculation did not include data that evaluated the heat resistance after stress conditions or data for Salmonella Senftenberg . The heat resistance of Salmonella is highly influenced by the strain tested, the type of experiment (log reduction versus end-point), culture conditions prior to the experiment, heating menstruum, and recovery conditions . Heat resistance data for Salmonella are still nonexistent or scarce in chicken meat, fruit juices, and aquacultured fish.

J Food Prot, 2000 Jun, 63(6), 727 - 34
Antibacterial mechanism of allyl isothiocyanate; Lin CM et al.; Allyl isothiocyanate (AITC), a natural compound in plants belonging to the family Cruciferae, has been shown to have strong antimicrobial activity in liquid media as well as in its vapor form . To understand its antimicrobial mechanism, AITC was tested for bactericidal activities to Salmonella Montevideo, Escherichia coli O157:H7, and Listeria monocytogenes Scott A at different stages of growth and was compared with streptomycin, penicillin G, and polymyxin B, each of known antibacterial mechanisms . Bactericidal activities were determined by measuring bacterial viability and leakage of metabolites . To determine its effects on membrane permeability, beta-galactosidase activity was examined after exposure of E . coli K-12 strain 3.300 to the three antibiotics and to AITC . The two gram-negative bacteria, Salmonella Montevideo and E . coli O157:H7, were more sensitive to AITC and to polymyxin B than the gram-positive L . monocytogenes . AITC and polymyxin B were effective bactericidal agents to bacteria at all growth stages, whereas penicillin G and streptomycin did not exhibit bactericidal activity to stationary cells . High A260 and A280 values of cellular filtrate and beta-galactosidase activity were obtained after treatments of AITC and polymyxin B . These data indicated that AITC was most similar to polymyxin B with respect to its antibacterial effect on cell membranes and on leakage of cellular metabolites . Gaseous AITC caused metabolite leakages, measurable increases in 3-galactosidase activity, and reduction of viable bacteria . The effectiveness of AITC in inhibiting bacteria at all growth stages and its strong activity in vapor phase support its application in food preservation.

Indian J Chest Dis Allied Sci, 2000 Jan-Mar, 42(1), 31 - 3
Pleural involvement by Salmonella senftenberg: a report of two cases; Ramanathan RM et al.; Non-typhoidal serovars of salmonella are an unusual cause of pleuropulmonary infections . We report two patients with empyema caused by Salmonella senftenberg . One patient had associated diabetes and gall bladder carcinoma, and infection was acquired in hospital . Both patients responded well to parenteral antibiotics.

J Bacteriol, 2000 Jul, 182(13), 3874 - 6
Phosphorylated PmrA interacts with the promoter region of ugd in Salmonella enterica serovar typhimurium; Aguirre A et al.; The Salmonella PmrA-PmrB system controls the expression of genes necessary for polymyxin B resistance . Four loci were previously identified as part of the regulon, and interaction of PmrA with the promoter region of three of them was observed . Here we characterized the interaction of PmrA with the promoter region of ugd, previously suggested to be regulated indirectly by PmrA . Our results indicate that PmrA controls the expression of ugd by interacting with a specific sequence in the promoter region of this gene.

J Bacteriol, 2000 Jul, 182(13), 3638 - 43
Evidence for a signaling system in Helicobacter pylori: detection of a luxS-encoded autoinducer; Joyce EA et al.; Helicobacter pylori possesses a homolog of the luxS gene, initially identified by its role in autoinducer production for the quorum-sensing system 2 in Vibrio harveyi . The genomes of several other species of bacteria, notably Escherichia coli, Salmonella enterica serovar Typhimurium, and Vibrio cholerae, also include luxS homologs . All of these bacteria have been shown to produce active autoinducers capable of stimulating the expression of the luciferase operon in V . harveyi . In this report, we demonstrate that H . pylori also synthesizes a functional autoinducer (AI-2) that can specifically activate signaling system 2 in V . harveyi . Maximal activity is produced during early log phase, and the activity is diminished when cells enter stationary phase . We show that AI-2 is not involved in modulating any of the known or putative virulence factors in H . pylori and that a luxS null mutant has a two-dimensional protein profile identical to that of its isogenic parent strain . We discuss the implications of having an AI-2-like quorum-sensing system in H . pylori and suggest possible roles that it may play in H . pylori infection.

J Med Microbiol, 2000 Jun, 49(6), 503 - 11
Comparative study of the invasiveness of Salmonella serotypes Typhimurium, Choleraesuis and Dublin for Caco-2 cells, HEp-2 cells and rabbit ileal epithelia; Bolton AJ et al.; Patterns of invasiveness of Salmonella serotypes Typhimurium, Choleraesuis and Dublin in Caco-2 cells (without centrifugation) were compared with previously published studies of the rabbit ileal invasion assay (RIIA) and (where relevant) a HEp-2 cell invasion assay . Optimal conditions for the use of Caco-2 cell monolayers in bacterial invasion assays were defined . Centrifuge-assisted attachment of bacteria to cells was not used routinely as this increased the invasiveness of known hypo-invasive strains and detachment of Caco-2 cells . Inocula with too high bacterial numbers resulted in rapid acidification of media and detachment of the monolayers . The invasiveness of Typhimurium strains TML, WAKE, WII8, LT7, SL1027 and M206 in Caco-2 cells reflected that seen in the RIIA . The invasiveness of Choleraesuis strain A50 was similar to that in the RIIA except that bacteria grown at 37 degrees C and used without storage at 4 degrees C were slightly more invasive than those grown at 37 degrees C and stored at 4 degrees C before use . Dublin strain 3246 showed no apparent temperature-regulated invasiveness in Caco-2 cells, in contrast to the results observed in the RIIA . Dublin strain 3246 did not cleave tight junctions in the Caco-2 cell monolayer as it did in rabbit ileal epithelia both in vitro and in vivo . Three TnphoA insertion LPS mutants of Typhimurium TML were uniformly hypo-invasive in both Caco-2 cells and the RIIA; in contrast, they were differentially invasive in HEp-2 cells . Three smooth TnphoA insertion mutants of Typhimurium TML (invH, invG and pagC) were hypo-invasive in both the Caco-2 and HEp-2 cell invasion assays but not in the RIIA.

Eur J Epidemiol, 2000 Feb, 16(2), 135 - 9
Surveillance of multidrug-resistant strains of Salmonella enterica serotype Typhimurium in southern Italy in the years 1992-1997; Nastasi A et al.; Spread of multidrug-resistant strains of Salmonella enterica serotype Typhimurium (S . typhimurium) is increasingly reported worldwide . The presence of a pattern of resistance to ampicillin, chloramphenicol, streptomycin, sulfonamides and tetracycline (ACSSuT), in some cases associated to trimethoprim and infrequently to quinolones, is of particular concern . This resistance pattern appears to be chromosomally encoded and, in most epidemiological studies, closely related to definitive type 104 (DT104) . In southern Italy multidrug-resistant isolates of S . typhimurium had been identified since 1980, but only during 1992 S . typhimurium strains with chromosomally encoded drug resistance were first isolated from domestic animals . One hundred fifty-five isolates--52.5% of the multidrug-resistant strains identified in the years 1992-1997--were submitted to phage typing and plasmid profile analysis . Ribotyping was also performed in comparison with a random sample of 150 strains susceptible or resistant to three or less antibiotics identified in the same interval of time . Four ribotypes (RTs)--1, 5, 8, and 48--included approximately 90% of the multiresistant strains, RT8 accounting for 61.2% . Phage type (PT) 193 is the most prevalent phage type . Phage typing and ribotyping suggest that few bacterial clones are involved in spread of multidrug-resistant S . typhimurium strains in southern Italy.

Mol Microbiol, 2000 Jun, 36(5), 1015 - 23
Salmonella pathogenicity island 2; Hensel M; Systemic infections by Salmonella enterica, such as typhoid fever, are a significant threat to human health . Recent studies indicate that the function of a type III secretion system encoded by Salmonella Pathogenicity Island 2 (SPI2) is central for the ability of S . enterica to cause systemic infections and for intracellular pathogenesis . This review summarizes approaches leading to the identification of SPI2, the molecular genetics and evolution of SPI2, and the current understanding of the regulation of gene expression . Recent studies have indicated that SPI2 is used by intracellular Salmonella to actively modify functions of the host cells . The role of SPI2 during pathogenesis of salmonellosis and current models regarding function will be discussed.

Mol Microbiol, 2000 Jun, 36(5), 1006 - 14
Host adaptation and the emergence of infectious disease: the Salmonella paradigm; Kingsley RA et al.; The recent emergence of food-borne pathogens, such as Salmonella enterica serotype Enteritidis (S . enteritidis) and Escherichia coli O157:H7, has generated increasing interest in how infectious diseases can invade, persist and spread within new host populations . To alter their host range pathogens require adaptations, which ensure their circulation in a new animal population . Adaptations for circulation in different populations of vertebrate hosts seem to have been acquired multiple times within the genus Salmonella because extant Salmonella serotypes differ greatly with regard to host range . In this article, mechanisms involved in host adaptation are deduced by considering the influence of the host immune response on circulation of Salmonella serotypes within populations of vertebrate animals . This approach contributes to the identification of genes involved in host adaptation and provides new insights into the emergence of food-borne pathogens.

Mol Microbiol, 2000 Jun, 36(5), 997 - 1005
Molecular basis of Salmonella-induced enteritis; Wallis TS et al.; Salmonella pathogenesis is a complex and multifactorial phenomenon . Many genes required for full virulence in mice have been identified, but only a few of these have been shown to be necessary for the induction of enteritis . Likewise, at least some of the Salmonella virulence factors affecting enteritis do not appear to be required for infection of systemic sites in mice . This suggests that subsets of virulence genes influence distinct aspects of Salmonella pathogenesis . Recently, considerable progress has been made in characterizing the virulence mechanisms influencing enteritis caused by non-typhoid Salmonella spp . The Salmonella pathogenicity island-1-encoded type III secretion system mediates the translocation of secreted effector proteins into target epithelial cells . These effector proteins are key virulence factors required for Salmonella intestinal invasion and the induction of fluid secretion and inflammatory responses.

Mol Microbiol, 2000 May, 36(3), 749 - 61
Salmonella SsrB activates a global regulon of horizontally acquired genes; Worley MJ et al.; Salmonella enterica is a bacterial pathogen of humans that can proliferate within epithelial cells as well as professional phagocytes of the immune system . This ability requires an S . enterica specific locus termed Salmonella pathogenicity island 2 (SPI-2) . SPI-2 encodes a type III secretion system that injects effectors encoded within the island into host cell cytosol to promote virulence . SsrAB is a two-component regulator encoded within SPI-2 that was assumed to activate SPI-2 genes exclusively . Here, it is shown that SsrB in fact activates a global regulon . At least 10 genes outside SPI-2 are SsrB regulated within epithelial and macrophage cells . Nine of these 10 SsrB-regulated genes outside SPI-2 reside within previously undescribed regions of the Salmonella genome . Most share no sequence homology with current database entries . However, one is remarkably homologous to human glucosyl ceramidase, an enzyme involved in the ceramide signalling pathway . The SsrB regulon is modulated by the two-component regulatory systems PhoP/PhoQ and OmpR/EnvZ, and is upregulated in the intracellular microenvironment.

Mutat Res, 2000 May 8, 467(2), 113 - 7
Chlorophyllin {CHLN} and the mutagenicity of monofunctional alkylating agents in Drosophila: the action of CHLN need not include an influence on metabolic activation; Olvera O et al.; The effect of chlorophyllin (CHLN) on the mutagenicity of four monofunctional alkylating agents (MFAAs) was evaluated in the wing spot test in Drosophila . Three of the compounds are direct-acting (ethylnitrosamine (ENU), methylnitrosourea (MNU), and methylmethanesulfonate (MMS)) and one indirect-acting (diethylnitrosamine, DEN) . Results indicate that the mutagenicity of all four compounds is strongly inhibited by CHLN . The findings are not in agreement with the conclusion of Romert et al . (1992) that CHLN has no effect on the mutagenicity of direct acting MFFAs inferred from their work with MNU and ethylmethanesulfonate (EMS) in the V79 and Salmonella in vitro test systems . The results suggest the possibility that the action of CHLN need not include an inhibiting effect on metabolic activation.

Mutat Res, 2000 May 30, 450(1-2), 5 - 17
Influence of DNA repair on mutation spectra in Salmonella; DeMarini DM; This paper reviews the influence of DNA repair on spontaneous and mutagen-induced mutation spectra at the base-substitution (hisG46) and -1 frameshift (hisD3052) alleles present in strains of the Salmonella (Ames) mutagenicity assay . At the frameshift allele (mostly a CGCGCGCG target), DeltauvrB influences the frequency of spontaneous hotspot mutations (-CG), duplications, and deletions, and it also shifts the sites of deletions and duplications . Cells with pKM101+DeltauvrB spontaneously produce complex frameshifts (frameshifts with an adjacent base substitution) . The spontaneous frequency of 1-base insertions or concerted (templated) mutations is unaffected by DNA repair, and neither mutation is inducible by mutagens . Glu-P-1, 1-nitropyrene (1NP), and 2-acetylaminofluorene (2AAF) induce only hotspot mutations and are unaffected by pKM101, whereas benzo(a)pyrene and 4-aminobiphenyl induce only hotspot in pKM101(-), and hotspot plus complex in pKM101(+) . At the base-substitution allele (mostly a CC/GG target), the DeltauvrB allele increases spontaneous transitions in the absence of pKM101 and increases transversions in its presence . The frequency of suppressor mutations is decreased 4x by DeltauvrB, but increased 7 . 5x by pKM101 . Both repair factors cause a shift in the proportion of mutations to the second position of the CC/GG target . With UV light and gamma-rays, the DeltauvrB allele increases the proportion of transitions relative to transversions . pKM101 is required for mutagenesis by Glu-P-1 and 4-AB, and the types and positions of the substitutions are not altered by the addition of the DeltauvrB allele . Changes in DNA repair appear to cause more changes in spontaneous than in mutagen-induced mutation spectra at both alleles . There is a high correlation (r(2)=0.8) between a mutagen's ability to induce complex frameshifts and its relative base-substitution/frameshift mutagenic potency . A mutagen induces the same primary class of base substitution in TA100 (DeltauvrB, pKM101) as it does in Escherichia coli, mammalian cells, or rodents as well as in the p53 gene of human tumors associated with exposure to that mutagen . Thus, a mutagen induces the same primary class of base substitution in most organisms, reflecting the conserved nature of DNA replication and repair processes.

Kansenshogaku Zasshi, 2000 Apr, 74(4), 345 - 52
{Increasing nalidixic-acid-resistance in Salmonella strains isolated from sporadic cases in Tokyo}; Matsushita S et al.; A total of 118 nalidixic-acid (NA)-resistant Salmonella strains consisting of 68 domestic strains and 50 imported strains isolated during 1988-1998 in Tokyo were examined regarding their annual incidence, serovars, drug-resistance patterns, and minimum inhibitory concentrations(MIC) to fluoroquinolones (NFLX, OFLX, ENX, and CPFX) . NA-resistant strains accounted for 1.3% of all Salmonella (5,302 strains) isolated from domestic cases, and 2.5% of all Salmonella (1,981 strains) isolated from imported cases . The incidence of NA-resistant strains has increased since 1995, and it has been remarkable in imported cases . The results of the serotyping showed that the NA-resistant strains were classified into 25 serovars, excluding untypable strains . Among those, S . Enteritidis (21 strains), S . Blockley (13 strains), S . Litchifield (13 strains), S . Typhimurium (13 strains), S . Hadar (9 strains), and S . Virchow (8 strains) were predominant . Drug-resistance patterns of NA-resistant strains, including other drugs (CP, TC, SM, KM, ABPC, ST, FOM, and NFLX) tested varied among the 26 types . Among those, multidrug-resistant strains accounted for 61.9% (73 strains), and one strain among them was high-resistant to NFLX . MIC distribution of NA-resistant strains to fluoroquinolones showed that the ranges of all drugs were 4-128 times higher than NA-sensitive strains used for controls.

Nat Biotechnol, 2000 Jun, 18(6), 645 - 8
Surface-displayed viral antigens on Salmonella carrier vaccine; Lee JS et al.; We have developed a recombinant live oral vaccine using the ice-nucleation protein (Inp) from Pseudomonas syringae to display viral antigens on the surface of Salmonella spp . Fusion proteins containing viral antigens were expressed in the oral vaccine strain, Salmonella typhi Ty21a . Surface localization was verified by immunoblotting and fluorescence-activated cell sorting . The immunogenicity of surface-displayed viral antigens on the recombinant live vaccine strain was assessed in mice inoculated intranasally and intraperitoneally . Inoculation resulted in significantly higher serum antibody level than those induced by viral antigens expressed intracellularly . Thus, this multivalent mucosal live vaccine may provide an effective means for inducing mucosal or systemic immune responses against multiple viral antigens.

J Clin Microbiol, 2000 Jun, 38(6), 2403 - 6
Epidemiologic typing of Salmonella enterica serotype enteritidis in a Canada-wide outbreak of gastroenteritis due to contaminated cheese; Ahmed R et al.; A major Canada-wide outbreak of gastroenteritis due to Salmonella enterica serotype Enteritidis phage type (PT) 8 occurred in 1998, and this was traced to contaminated cheese in a commercial lunch pack product . Phage typing and pulsed-field gel electrophoresis linked the clinical and cheese isolates of serotype Enteritidis but failed to differentiate outbreak from nonoutbreak PT 8 strains . Further differentiation was made by biotyping based on melibiose fermentation.

Eur J Clin Microbiol Infect Dis, 2000 Apr, 19(4), 275 - 81
Evaluation of phenotypic and genotypic markers for characterisation of the emerging gastroenteritis pathogen Salmonella hadar; Valdezate S et al.; Over the last 4 years Salmonella hadar has increasingly been isolated in Europe in conjunction with food-borne gastroenteritis . The aim of this study was to evaluate epidemiological methods (phage typing, antimicrobial susceptibility testing, DNA plasmid analysis, ribotyping and pulsed-field gel electrophoresis analysis) for characterising Salmonella hadar isolates . The 100% phage typeability of isolates and the high discriminatory index of 0.8856 suggest that phage typing is the method of choice . In order to obtain subdivisions of the most frequent Salmonella hadar phage types, a combination of molecular methods, such as ribotyping performed with Bg/I and EcoRI or pulsed-field gel electrophoresis using XbaI and XhoI, would be desirable as the usefulness of each technique varies with the phage type being analysed . Of note was the high (86%) rate of resistance to tetracycline and nalidixic acid but full susceptibility to ciprofloxacin in the strains studied.

Microbiology, 2000 May, 146 ( Pt 5), 1171 - 8
The Salmonella FlgA protein, a putativeve periplasmic chaperone essential for flagellar P ring formation; Nambu T et al.; P ring is a periplasmic substructure of the flagellar basal body and is believed to connect with the peptidoglycan layer in Salmonella . Two flagellar genes, flgA and flgI, are known to be indispensable for P ring formation . The flgI gene encodes the component protein of the P ring . However, the role of the flgA gene product in P ring assembly remained unknown . Here, evidence is presented that FlgA is synthesized as a precursor form and exported via the Sec secretory pathway into the periplasmic space where P ring formation takes place . Overproduction of the FlgI protein led flgA mutants to form flagella with a P ring, suggesting that FlgA plays an auxiliary role in P ring assembly . Far-Western blot analysis revealed that FlgA binds in vitro to both FlgI and FlgA itself . Though a direct FlgI-FlgI interaction in the absence of FlgA could not be demonstrated, an indirect or direct interaction between the FlgI proteins was observed in the presence of FlgA . FlgA alone was very unstable in vivo, but co-expression with FlgI could stabilize FlgA . This suggests the presence of FlgA-FlgI interaction in vivo . On the basis of these results, a hypothesis is proposed that FlgA acts as a periplasmic chaperone, which assists a polymerization reaction of FlgI into the P ring through FlgA-FlgI interaction.

Vet Microbiol, 2000 Jun 12, 74(4), 345 - 51
Dynamics of lymphocyte subpopulation changes in the cecal tonsils of chickens infected with Salmonella enteritidis; Sasai K et al.; Salmonella enteritidis (SE)-induced changes in various T and B lymphocyte subpopulations in the cecal tonsils of chickens were analyzed using flow cytometry . At 1 day post-SE inoculation, the percentages of CD3(+) and CD8(+) T lymphocytes were significantly decreased in the group inoculated with 1x10(9) SE colony-forming units (CFU) (SE high) and in the group inoculated with 1x10(6) SE CFU (SE low) compared with the uninfected control group . The percentage of CD4(+) T lymphocytes was significantly increased in the SE high group compared to the uninfected and the SE low groups at 4 days after SE inoculation . The percentage of IgG(+) B lymphocytes was also significantly increased in both SE high and low groups compared to the uninfected control at 6 days post-SE inoculation . In contrast, the SE low group showed significantly fewer IgM(+) B lymphocytes compared to the uninfected and SE high groups . These results show that SE infection induces significant changes in the cecal tonsil lymphocytes subpopulations shortly following SE inoculation.

Microbiol Res, 2000 Apr, 155(1), 65 - 8
The role of ferrioxamine E in pre-enrichment medium for determining Salmonella in environmental samples according to ISO method; Heinonen-Tanski H et al.; The effect of a siderophoric compound, ferrioxamine E, in the pre-enrichment broth on determining of Salmonella infantis in environmental samples was tested with combination of various pre-enrichment times and enrichment temperatures of 37 and 43 degrees C . Ferrioxamine E slightly improved the determination efficiency of this bacterium but the pre-enrichment time could not be reduced below 17 hours . The enrichment temperature of 43 degrees C was better than of 37 degrees C . The mixing ratios of 1:100 or 1:1000 for samples and pre-enrichment broth were more successful than the ratio of 1:10 as recommended by ISO.

Microbiol Res, 2000 Apr, 155(1), 45 - 7
Transient inhibition of glucose utilization by erythrocytes during the acute stage of typhoid fever; Khajehdehi P; The exact reason for hemolysis of glucose-6-phosphate dehydrogenase-deficient (G6PD) erythrocytes in patients with typhoid fever is unknown . Therefore, glucose utilization by normal and G6PD-deficient erythrocytes was measured during incubation with plasma of healthy controls as well as from patients in acute or recovery stages of typhoid fever . Glucose utilization in normal and G6PD-deficient erythrocytes significantly decreased compared to the controls when incubated with plasma of patients with acute typhoid fever, which normalized to the baseline after recovery from typhoid fever, suggesting an acquired alteration in G6PD enzyme properties by Salmonella typhi or its endotoxins.

Indian J Pediatr, 1995 Nov-Dec, 62(6), 703 - 5
Multiple drug resistant non typhoidal Salmonella spp associated with acute diarrheal disease; Ananthan S et al.; Rectal swabs/stool specimens from 115 children (0-5 years) suffering with acute diarrhea were screened for non typhoidal salmonella species . 7 (6%) patients were found to be positive for non typhoidal salmonella . 4 (3.47%) were positive for S . paratyphi B and 3 (2.6%) were positive for S . typhimurium . Multidrug resistance was seen in 57 percent of the strains . All strains were sensitive to Ciprofloxacin . All strains were resistant to Ampicillin followed by Ciprofloxacin . All strains were resistant to Ampicillin followed by Gentamycin (43%), Kanamycin (43%), Tetracycline (43%), Streptomycin (28.5%) and Chloramphenicol (28.5%).

Indian J Pediatr, 1995 Jul-Aug, 62(4), 445 - 8
An outbreak of multidrug resistant typhoid fever in Bangalore; Rathish KC et al.; Six hundred and eighty five blood cultures from children clinically diagnosed as enteric fever yielded 176 salmonella strains showing isolation success rate of 25.7%, S . typhi were 164 (93.2%), S . paratyphi A 5 (2.8%), S . choleraesuis 4 (2.3%) and S . typhimurium 3 (1.7%) . Antibiogram of 164 isolates of S . typhi showed triple drug resistance (TDR) in 156 strains (95.1%) to chloramphenicol, ampicillin and cotrimoxazole, and sensitivity of 90.2% and 95.1% to norfloxacin and ciprofloxacin respectively . Minimum inhibitory concentrations (MIC) of chloramphenicol were between 360 mcg and 640 mcg per ml . Phage types of 38 strains of TDR S . typhi were predominantly E1 and 0 with prevalences of 47.4% and 36.8% respectively in this region . All children with S . typhi isolates sensitive to quinolones in Vitro responded well to these drugs with almost no relapse and hence, the newer generation of quinolones could be considered as the first choice in the primary treatment of enteric fever.

J Nutr, 2000 Jun, 130(6), 1536 - 42
Copper deficiency suppresses effector activities of differentiated U937 cells; Huang ZL et al.; Dietary copper (Cu) deficiency impairs both innate and acquired branches of immunity . Specific roles of Cu in the activation and effector activities of host-defense cells remain largely unknown . The effects of Cu status on effector activities of a monocytic cell line were investigated as an initial step in the elucidation of specific functions of Cu in phagocytic cells . Exposure of differentiating U937 human promonocytic cells to 5 micromol/L 2,3, 2-tetraamine (tet), a high affinity Cu chelator, for 4 d decreased cellular Cu by 62% without altering cellular Cu,Zn-superoxide dismutase (SOD) activity, Zn content, mitochondrial activity and protein synthesis . In contrast, Cu deficiency suppressed the respiratory burst activity and markedly compromised the ability of U937 cells to kill SALMONELLA: Similarly, treatment of RAW264.7 murine macrophages with 5 micromol/L tet decreased cell Cu by 78% and Cu,Zn-SOD activity by 15% and increased bacterial survival by 180% . The tet-induced impairment of respiratory burst and bactericidal activities was blocked in cultures supplemented with Cu, but not Zn or Fe . In addition, lipopolysaccharide (LPS)-induced secretion of the inflammatory mediators, tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6 and prostaglandin E(2) (PGE(2)), was decreased by 30-60% in tet-treated U937 cells . Flow cytometric analysis of the surface antigens CD11b and CD71 showed that the suppressed activities of Cu-deficient cells were not due to an attenuation in the degree of differentiation or secondary iron deficiency . These data demonstrate that U937 cells provide a useful model for examining the biochemical roles of Cu in monocyte activity.

J Vet Diagn Invest, 2000 May, 12(3), 257 - 60
Assessment of the long-term shedding pattern of Salmonella serovar choleraesuis following experimental infection of neonatal piglets; Anderson RC et al.; In the United States, swine salmonellosis is most often attributed to infections by Salmonella serovar choleraesuis . As a host-adapted pathogen rarely found in nonswine sources, S . choleraesuis is thought to be spread primarily via horizontal transmission, with carrier animals playing an important role . Little has been reported regarding infection of neonatal piglets, particularly regarding their potential to become carriers . Evidence reported herein demonstrates that piglets experimentally infected by S . choleraesuis at 2 days of age were capable of shedding the pathogen for up to 85 days postinfection, at which time the study was concluded . This study also presents findings supporting the use of GN-Hajna as a preenrichment medium for the isolation of S . choleraesuis.

Vaccine, 2000 Jul 1, 18(26), 3031 - 9
Local and systemic immune responses to combined vibrio cholerae CVD103-HgR and salmonella typhi ty21a live oral vaccines after primary immunization and reimmunization; Kollaritsch H et al.; The local and systemic antibody responses elicited following concomitant primary immunization and reimmunization with the live oral attenuated Vibrio cholerae CVD103-HgR and Salmonella typhi Ty21a vaccine strains were determined in healthy adult volunteers . A more pronounced serum vibriocidal antibody response was generated after primary immunization compared to reimmunization 2.5 or 3.5 yr later . The seroconversion rate (> or =4-fold rise over baseline) was 81% subsequent to primary immunization versus 57% (p=0.018) and 65% (p=0.639) upon reimmunization at 2.5 and 3.5 yr, respectively . A similar trend was observed for serum anti-S . typhi lipopolysaccharide (LPS) antibodies . After primary immunization, 48% of subjects manifested a significant rise in coproantibody levels to V . cholerae LPS while 60% did so for cholera toxin (CT) . Upon reimmunization, the response rate for LPS ranged from 38% at 2.5 yr to 56% at 3.5 yr (p>0.05), while that for CT varied from 31% (p=0 . 007) to 50% (p=0.541) at 2.5 and 3.5 yr, respectively . The anti-S . typhi IgA coproantibody response rate was 70% subsequent to primary immunization versus 47% at 2.5 yr (p=0.021) and 63% at 3.5 yr (p=0 . 77).

Clin Infect Dis, 1999 Apr, 28(4), 822 - 7
Nontyphoid Salmonella bacteremia: age-related differences in clinical presentation, bacteriology, and outcome; Shimoni Z et al.; In a retrospective study, 80 episodes of nontyphoid salmonella (NTS) bacteremia in children were compared with 55 episodes in adults over a 10-year period . The study disclosed major differences in the predisposition, clinical presentation, and outcome as well as the microbiology of NTS bacteremia in relation to age . Adults were more likely than children to have predisposing diseases (95% vs . 15%, respectively; P < .0001) and to receive prior medications (95% vs . 23%, respectively; P < .0001), particularly immunosuppressive agents (58% vs . 5%, respectively; P < .0001) . In most adults (67%), NTS infection presented as a primary bacteremia and was associated with a high incidence of extraintestinal organ involvement (34%) and a high mortality rate (33%) . In children, NTS bacteremia was usually secondary to gastroenteritis (75%) and caused no fatalities . Although group D Salmonella (78%) and the serovar Salmonella enteritidis were the predominant isolates from adults, the emergence of infections due to group C Salmonella (46%) and the serovar Salmonella virchow in children was noted.

Indian J Med Res, 2000 Feb, 111, 40 - 2
Occurrence of sef & pef genes among different serovars of Salmonella; Rahman H et al.; A total of 29 strains of Salmonella enterica belonging to seven serovars isolated from human, animals and birds were used to study the occurrence of Salmonella fimbriae genes (sef and pef) by PCR amplification technique using their specific primers . All the strains (15) of S . Enteritidis were found to carry both sef and pef genes irrespective of the source of isolation . S . Typhimurium strains were found to harbour only pef genes, while S . Gallinarum strains harboured only sef genes . Other serovars namely, S . Newport, S . Kentucky, S . Weltevreden and S . Indiana were negative for both pef and sef genes . The importance of fimbriae in the pathogenesis of salmonellosis is suggested.

Br J Biomed Sci, 1999, 56(3), 177 - 81
Microbiological quality of prepared foods from selected kitchen outlets in Lahore, Pakistan; Danish F et al.; Following UK PHLS guidelines, a total of 166 food samples from a variety of different kitchen outlets were examined for microbiological quality . Over 60% of the samples had satisfactory aerobic plate counts, and only 10% (8.5-18.7% of the samples, depending on the nature of the product) were classified as unsatisfactory . Almost 85% of samples presented with low coliform counts, and 6.6% were found to have unsatisfactory or unacceptable levels . Salmonella was found in only one sample, which had been purchased from a street trader.

Ann Trop Paediatr, 2000 Mar, 20(1), 70 - 5
Osteomyelitis in sickle cell haemoglobinopathy with elevated fetal haemoglobin; Narchi H; The prevalence rate and characteristics of osteomyelitis in children below 15 years of age were studied in a population characterized by a high prevalence of sickle cell disease (SCD) with elevated fetal haemoglobin (HbF) . All children born in our institution routinely undergo a haemoglobinopathy screening test . Osteomyelitis developed in 25 children (16 boys and nine girls) with a mean age of 5.5 years . Fourteen had sickle cell disease (SCD) and 11 had no haemoglobinopathy . The prevalence of osteomyelitis in children with SCD was 69 times higher than in those without (283 vs 4/10(5)) . All 14 children with SCD and osteomyelitis also had elevated HbF . Three children had HbS alpha-thalassaemia, with mean HbF 24% and HbS 68.6% . Eleven children had sickle cell anaemia with elevated HbF, mean HbF 31.7% and HbS 66.7% . There was no significant difference in symptoms, signs, leucocyte, neutrophil and band counts, nor in sedimentation rates . Salmonella organisms were significantly more frequently responsible for osteomyelitis in SCD . The presence of elevated HbF in children with SCD should not lead to complacency as they are still at increased risk of developing osteomyelitis.

Ann Trop Paediatr, 2000 Mar, 20(1), 41 - 4
Salmonella meningitis in children in Blantyre, Malawi, 1996-1999; Molyneux EM et al.; Sixty-one episodes of Salmonella meningitis were identified during a 3-year period from February 1996 to January 1999 inclusive . These accounted for 6.8% of all the acute bacterial meningitis cases seen during this time . In contrast, only two children were admitted with Salmonella meningitis in 1982 . The increase may reflect the rise in HIV disease and the associated increase in Salmonella septicaemia . All but one child were under 2 years of age, only six children were well nourished and anaemia was common . The prognosis was poor: 33 (58%) died, 19 made a full recovery and five developed sequelae . Two children relapsed, one of whom died . Patients were routinely treated with chloramphenicol, to which all isolates were sensitive in vitro . The poor outcomes suggest that an alternative antibiotic policy is required.

Eur J Biochem, 2000 Jun, 267(11), 3160 - 7
Structure of the sialic acid-containing O-specific polysaccharide from Salmonella enterica serovar Toucra O48 lipopolysaccharide; Gamian A et al.; Lipopolysaccharide was extracted from cells of Salmonella enterica serovar Toucra O48 and, after mild acid hydrolysis (1% AcOH, 1 h, 100 degrees C or 0.1 M NaOH-AcOH, pH 4.5, 5 h, 100 degrees C), the O-specific polysaccharide was isolated and characterized . The core and an oligosaccharide containing a fragment of the repeating unit linked to the core region were also obtained, depending on hydrolysis conditions . On the basis of sugar and methylation analyses and NMR spectroscopy of the hydrolysis products, the biological repeating unit of the O-specific polysaccharide was shown to be the following trisaccharide: -->4)-alpha-Neup5Ac(2-->3)-L-alpha-FucpNAc(1-->3)-D-beta-Glc pNAc(1--> The polysaccharide O-chain was substituted with a single molar equivalent of O-acetyl group, distributed between the Neu5Ac O-9 and O-7 positions, in an approximate ratio of 7 : 3.

Prev Vet Med, 2000 Jun 12, 45(3-4), 297 - 304
Preliminary findings of Salmonella spp . in captive green iguanas (Iguana iguana) and their environment; Mitchell MA et al.; Captive reptiles are routinely identified as reservoirs of Salmonella spp . and reports of reptile-associated salmonellosis are increasing . Unfortunately, little is known about the epidemiology of Salmonella spp . and green iguanas . We did a limited survey of a green-iguana farm in El Salvador to identify sources of Salmonella spp . in green iguanas and their environment . A limited number of samples for microbiological culture were collected from iguanas (adult, hatchling, and embryos) and their environment (food, water, soil, shelter, insects, and wild-caught lizards) . Salmonella spp . was isolated from the intestine of both adult (3/20) and hatchling iguanas (8/20) . There was no evidence of Salmonella spp . in the reproductive tracts of female iguanas (0/10) . Salmonella spp . was isolated from the surface of 40% (7/16) of the egg surfaces tested . Salmonella spp . was not identified from the externalized yolk-sac of the iguana embryos tested . Soil samples from a breeding pen and a nest were both positive for Salmonella spp . Eight different Salmonella spp . serotypes were identified in this survey . These results suggest that horizontal transmission of Salmonella spp . is a potential source of exposure to hatchling iguanas at this facility.

J Biol Chem, 2000 May 26, 275(21), 16281 - 8
Live Salmonella modulate expression of Rab proteins to persist in a specialized compartment and escape transport to lysosomes; Hashim S et al.; We investigated the intracellular route of Salmonella in macrophages to determine a plausible mechanism for their survival in phagocytes . Western blot analysis of isolated phagosomes using specific antibodies revealed that by 5 min after internalization dead Salmonella-containing phagosomes acquire transferrin receptors (a marker for early endosomes), whereas by 30 min the dead bacteria are found in vesicles carrying the late endosomal markers cation-dependent mannose 6-phosphate receptors, Rab7 and Rab9 . In contrast, live Salmonella-containing phagosomes (LSP) retain a significant amount of Rab5 and transferrin receptor until 30 min, selectively deplete Rab7 and Rab9, and never acquire mannose 6-phosphate receptors even 90 min after internalization . Retention of Rab5 and Rab18 and selective depletion of Rab7 and Rab9 presumably enable the LSP to avoid transport to lysosomes through late endosomes . The presence of immature cathepsin D (48 kDa) and selective depletion of the vacuolar ATPase in LSP presumably contributes to the less acidic pH of LSP . In contrast, proteolytically processed cathepsin D (M(r) 17,000) was detected by 30 min on the dead Salmonella-containing phagosomes . Morphological analysis also revealed that after uptake by macrophages, the dead Salmonella are transported to lysosomes, whereas the live bacteria persist in compartments that avoid fusion with lysosomes, indicating that live Salmonella bypass the normal endocytic route targeted to lysosomes and mature in a specialized compartment.

West Afr J Med, 2000 Jan-Mar, 19(1), 34 - 8
Determination of diagnostic Widal titres in Kumasi, Ghana; Frimpong EH et al.; Three hundred and seven healthy food handlers and 34 blood-culture positive enteric fever patients were screened for Salmonellae agglutinins using the Widal test . Of the 307 healthy food handlers, only 3 (1.0%) had an anti-O titre of > or = 1/160 and 8 (2.6%) an anti-H titre of > or = 1/320 for Salmonella typhi, but the majority, 214 (69.7%) and 149 (48.5%) had titres of < 1/20 for O and H agglutinins respectively . Similar agglutinin titres were also seen for S . Paratyphi A, B, and C . In the 34 enteric fever patients, for S typhi, based on anti-O titre of > or = 1/160, 25 persons showed a significant titre, a sensitivity of 73.5%, and a specificity of 99.0% . And 21 persons showed a significant titre of > or = 1/320 for anti-H, a sensitivity of 61.8% and a specificity of 97.4% . Based on these findings, titres of > or = 1/160 and > or = 1/320 for anti-0 and anti-H respectively, were considered diagnostic for enteric fever in Kumasi, Ghana.

JAMA, 2000 May 24-31, 283(20), 2668 - 73
Laboratory-based surveillance of Salmonella serotype Typhi infections in the United States: antimicrobial resistance on the rise; Ackers ML et al.; CONTEXT: Multidrug-resistant Salmonella serotype Typhi infections have been reported worldwide, but data on the incidence of resistant strains in the United States are lacking . OBJECTIVES: To determine the incidence of antimicrobial-resistant Salmonella Typhi infections and to identify risk factors for infection . DESIGN: Cross-sectional laboratory-based surveillance study . SETTING AND PARTICIPANTS: A total of 293 persons with symptomatic typhoid fever who had Salmonella Typhi isolates and epidemiological information submitted to US public health departments and laboratories from June 1, 1996, to May 31, 1997 . MAIN OUTCOME MEASURES: Proportion of Salmonella Typhi isolates demonstrating resistance to 12 antimicrobial agents; patient epidemiological factors associated with drug-resistant infections . RESULTS: Median age was 21 years (range, 3 months to 84 years); 56% were male . Two hundred twenty-eight (80%) were hospitalized; 2 died . In the 6 weeks before illness onset, 81% of patients had traveled abroad . Seventy-four Salmonella Typhi isolates (25%) were resistant to 1 or more antimicrobial agent, and 51 (17%) were resistant to 5 or more agents, including ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole (multidrug-resistant Salmonella Typhi {MDRST}) . Although no resistance to ciprofloxacin or ceftriaxone was observed, 20 isolates (7%) were nalidixic acid-resistant (NARST) . Patients with MDRST and NARST infections were more likely to report travel outside the United States, particularly to the Indian subcontinent (Bangladesh, India, and Pakistan) (odds ratio {OR}, 29.3; 95% confidence interval {CI}, 6.8-126.7; P<.001 and OR, 35.9; 95% CI, 3.4-377.3; P<.001, respectively) . CONCLUSIONS: Our data suggest that ciprofloxacin and ceftriaxone are appropriate empirical therapy for suspected typhoid fever; however, resistance may be anticipated . Continued monitoring of antimicrobial resistance among Salmonella Typhi strains will help determine vaccination and treatment policies . JAMA . 2000;283:2668-2673.

Lab Anim, 2000 Apr, 34(2), 217 - 22
Attempted eradication of salmonellosis from a colony of short-tail grey opossums (Monodelphis domestica); Wilkinson MJ et al.; Prior to re-housing a colony of laboratory short-tail grey opossums, the animals were found to harbour salmonella . This paper describes an unsuccessful attempt to eradicate the infection from the colony by means of antibiotic treatment and hygienic measures . A pilot treatment of five animals which received enrofloxacin 10 mg/kg for 5 days appeared to be successful in that no salmonellae were recovered from faeces or organs sampled after treatment . The process was repeated on the whole colony prior to a change of accommodation but 2 animals were found to be still infected, 5 weeks after cessation of treatment.

Infect Immun, 2000 Jun, 68(6), 3780 - 3
Curli loci of Shigella spp; Sakellaris H et al.; An unstable chromosomal element encoding multiple antibiotic resistance in Shigella flexneri serotype 2a was found to include sequences homologous to the csg genes encoding curli in Escherichia coli and Salmonella enterica serovar Typhimurium . As curli have been implicated in the virulence of serovar Typhimurium, we investigated the csg loci in all four species of Shigella . DNA sequencing and PCR analysis showed that the csg loci of a wide range of Shigella strains, of diverse serotypes and different geographical distributions, were almost universally disrupted by deletions or insertions, indicating the existence of a strong selective pressure against the expression of curli . Strains of enteroinvasive E . coli (EIEC), which share virulence traits with Shigella spp . and cause similar diseases in humans, also possessed insertions or deletions in the csg locus or were otherwise unable to produce curli . Since the production of curli is a widespread trait in environmental isolates of E . coli, our results suggest that genetic lesions that abolish curli production in the closely related genus Shigella and in EIEC are pathoadaptive mutations.

Infect Immun, 2000 Jun, 68(6), 3772 - 5
A functional cra gene is required for Salmonella enterica serovar typhimurium virulence in BALB/c mice; Allen JH et al.; A minitransposon mutant of Salmonella enterica serovar Typhimurium SR-11, SR-11 Fad(-), is unable to utilize gluconeogenic substrates as carbon sources and is avirulent and immunogenic when administered perorally to BALB/c mice (M . J . Utley et al., FEMS Microbiol . Lett., 163:129-134, 1998) . Here, evidence is presented that the mutation in SR-11 Fad(-) that renders the strain avirulent is in the cra gene, which encodes the Cra protein, a regulator of central carbon metabolism.

Infect Immun, 2000 Jun, 68(6), 3768 - 71
Mutation of waaN reduces Salmonella enterica serovar Typhimurium-induced enteritis and net secretion of type III secretion system 1-dependent proteins; Watson PR et al.; Mutation of waaN, a gene involved in lipid A biosynthesis, reduced enteropathogenic responses induced by Salmonella enterica serovar Typhimurium in bovine ligated ileal loops . However, the secretion of key virulence determinants was also reduced, and therefore the reduction in enteropathogenicity cannot be solely attributed to a reduction in biological activity of lipid A.

Infect Immun, 2000 Jun, 68(6), 3758 - 62
Constitutive mutations of the Salmonella enterica serovar Typhimurium transcriptional virulence regulator phoP; Gunn JS et al.; The PhoP-PhoQ two-component system is necessary for the virulence of Salmonella spp . and is responsible for regulating several modifications of the lipopolysaccharide (LPS) . Mutagenesis of the transcriptional regulator phoP resulted in the identification of a mutant able to activate transcription of regulated genes approximately 100-fold in the absence of PhoQ . Sequence analysis showed two single-base alterations resulting in amino acid changes at positions 93 (S93N) and 203 (Q203R) . These mutations were individually created, and although each resulted in a constitutive phenotype, the double mutant displayed a synergistic effect both in the induction of PhoP-activated gene expression and in resistance to antimicrobial peptides . The constitutive phoP gene was placed under the control of an arabinose-inducible promoter to examine the kinetics of PhoP-activated gene induction and the resultant modifications of LPS . Gene induction and 2-hydroxymyristate modification of the lipid A were shown to occur within minutes of the addition of arabinose and to peak at 4 h . As the first constitutive mutant of phoP identified, this allele will be invaluable to future genetic and biochemical studies of this and likely other regulatory systems.

Infect Immun, 2000 Jun, 68(6), 3744 - 7
Salmonella enterica serovars Typhimurium and Dublin can lyse macrophages by a mechanism distinct from apoptosis; Watson PR et al.; Salmonella enterica serovars Typhimurium and Dublin lysed primary bovine alveolar macrophages and immortalized J774.2 macrophage-like cells in the absence of either the morphological changes or DNA fragmentation characteristic of apoptosis . Macrophage lysis was dependent on a subset of caspases and an intact sipB gene.

Infect Immun, 2000 Jun, 68(6), 3419 - 25
The response regulator PhoP is important for survival under conditions of macrophage-induced stress and virulence in Yersinia pestis; Oyston PC et al.; The two-component regulatory system PhoPQ has been identified in many bacterial species . However, the role of PhoPQ in regulating virulence gene expression in pathogenic bacteria has been characterized only in Salmonella species . We have identified, cloned, and sequenced PhoP orthologues from Yersinia pestis, Yersinia pseudotuberculosis, and Yersinia enterocolitica . To investigate the role of PhoP in the pathogenicity of Y . pestis, an isogenic phoP mutant was constructed by using a reverse-genetics PCR-based strategy . The protein profiles of the wild-type and phoP mutant strains, grown at either 28 or 37 degrees C, revealed more than 20 differences, indicating that PhoP has pleiotrophic effects on gene expression in Y . pestis . The mutant showed a reduced ability to survive in J774 macrophage cell cultures and under conditions of low pH and oxidative stress in vitro . The mean lethal dose of the phoP mutant in mice was increased 75-fold in comparison with that of the wild-type strain, indicating that the PhoPQ system plays a key role in regulating the virulence of Y . pestis.

Infect Immun, 2000 Jun, 68(6), 3368 - 76
Transcriptional organization and function of invasion genes within Salmonella enterica serovar Typhimurium pathogenicity island 1, including the prgH, prgI, prgJ, prgK, orgA, orgB, and orgC genes; Klein JR et al.; Salmonella enterica serovar Typhimurium initiates infection of a host by inducing its own uptake into specialized M cells which reside within the epithelium overlaying Peyer's patches . Entry of Salmonella into intestinal epithelial cells is dependent upon invasion genes that are clustered together in Salmonella pathogenicity island 1 (SPI-1) . Upon contact between serovar Typhimurium and epithelial cells targeted for bacterial internalization, bacterial proteins are injected into the host cell through a type III secretion system that leads to internalization of the bacteria . Previous work has established that the prgH, -I, -J, and -K and orgA genes reside in SPI-1, and the products of these genes are predicted to be components of the invasion secretion apparatus . We report that an error in the published orgA DNA sequence has been identified so that this region encodes two small genes rather than a single large open reading frame . These genes have been designated orgA and orgB . Additionally, an opening reading frame downstream of orgB, which we have designated orgC, has been identified and partially characterized . Previously published work has indicated that the prgH, -I, -J, and -K genes are transcribed from a promoter distinct from that used by the gene immediately downstream, orgA . Here, we present experiments indicating that orgA expression is driven by the prgH promoter . In addition, using reverse transcriptase PCR analysis, we have found that this polycistronic message extends downstream of prgH to include a total of 10 genes . To more fully characterize this invasion operon, we demonstrate that the prgH, prgI, prgJ, prgK, orgA, and orgB genes are each required for invasion and secretion, while orgC is not essential for the invasive phenotype.

Infect Immun, 2000 Jun, 68(6), 3344 - 8
Antibody is required for protection against virulent but not attenuated Salmonella enterica serovar typhimurium; McSorley SJ et al.; Resolution of infection with attenuated Salmonella is an active process that requires CD4(+) T cells . Here, we demonstrate that costimulation via the surface molecule CD28, but not antibody production by B cells, is required for clearance of attenuated aroA Salmonella enterica serovar typhimurium . In contrast, specific antibody is critical for vaccine-induced protection against virulent bacteria . Therefore, CD28(+) CD4(+) T cells are sufficient for clearance of avirulent Salmonella in naive hosts, whereas CD4(+) T cells and specific antibodies are required for protection from virulent Salmonella in immune hosts.

Infect Immun, 2000 Jun, 68(6), 3305 - 13
Characterization of FimY as a coactivator of type 1 fimbrial expression in Salmonella enterica serovar Typhimurium; Tinker JK et al.; Type 1 fimbriae of Salmonella enterica serovar Typhimurium are surface appendages that carry adhesins specific for mannosylated host glycoconjugates . Regulation of the major fimbrial subunit is thought to be controlled by a number of ancillary fim genes, including fimZ, fimY, fimW, and fimU . Previous studies using a FimZ mutant have indicated that this protein is necessary for fimA expression, and in vitro DNA binding assays determined that FimZ is a transcriptional activator that binds directly to the fimA promoter . To determine the role of FimY as a potential regulator of fimbrial expression, a fimY mutant of serovar Typhimurium was generated by allelic exchange . This mutant was found to be phenotypically nonfimbriate . No transcription from the fimA promoter was detected in a fimY mutant containing a fimA-lacZ reporter construct located on the chromosome . In addition, transcription from the cloned fimY promoter was not detected in Escherichia coli unless both FimZ and FimY were present, indicating that these proteins also act as coactivators of fimY expression . Consistent with these results, there is no transcription from a fimY-lacZ reporter construct within a serovar Typhimurium fimY or fimZ mutant . Studies using the fimY-lacZ construct reveal that expression of this gene varies with environmental conditions in a manner similar to fimA expression . Extensive in vitro DNA binding assays using extracts from E . coli that overexpress FimY, as well as partially purified FimY, were unable to identify a specific interaction between FimY and the fimA or fimY promoter . The results indicate that FimY is a positive regulator of fimbrial expression and that this protein acts in cooperation with FimZ to regulate the expression of Salmonella type 1 fimbrial appendages.

Infect Immun, 2000 Jun, 68(6), 3280 - 5
CS22, a novel human enterotoxigenic Escherichia coli adhesin, is related to CS15; Pichel M et al.; Enterotoxigenic Escherichia coli (ETEC) expresses a broad spectrum of O:H antigens . Serogroup O20 is one of the most prevalent among the ETEC strains lacking any of the defined colonization factors (CFs), in Argentina . An O20:H- strain, ARG-3, adhered to Caco-2 cells and exhibited a thermoregulated 15.7-kDa protein band upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) . An antiserum against this protein inhibited ARG-3 adhesion to Caco-2 cells and bound to very thin fibrilla-like structures on the bacterial surface . A 15.7-kDa protein-defective mutant failed to adhere to Caco-2 cells and lacked immunogold-labeled surface structures . The N-terminal amino acid sequence of the structural subunit showed 95% homology to that of CS15 of ETEC (former antigen 8786) and 65% homology with fimbria SEF14 of Salmonella enterica serovar Enteritidis . Nevertheless, the molecular size of ARG-3 adhesin was different from that of CS15, as revealed by SDS-PAGE and mass spectrometry . Both proteins are immunologically related, yet not identical, since an antiserum against the 15.7-kDa protein reacted solely with ARG-3 after absorption with bacteria bearing CS15 . Moreover, only under low stringency conditions could DNA from strain ARG-3 be amplified by PCR using primers derived from the nfaA sequence of CS15 . Thus, from the DNA sequence obtained from the ARG-3 PCR product, it could be deduced that the subunit protein differed in 30 residues from that of CS15 . ARG-3 adhesin was found in 60% of the O20:H- CF-negative ETEC strains from Argentina; however, it appeared restricted to this serotype . We propose the designation CS22 for the herein identified nonfimbrial adhesin of human ETEC.

Infect Immun, 2000 Jun, 68(6), 3158 - 63
SspA is required for lethal Salmonella enterica serovar Typhimurium infections in calves but is not essential for diarrhea; Tsolis RM et al.; Salmonella pathogenicity island 1 (SPI-1) encodes virulence determinants, which are important for enteropathogenicity in calves . To determine whether the Salmonella enterica serovar Typhimurium SPI-1 effector proteins SspA and SptP are important for enteropathogenicity, strains lacking these proteins were tested during oral infection of calves . Calves infected with a sptP mutant or its isogenic parent developed diarrhea and lethal morbidity . In contrast, calves infected with an sspA mutant developed diarrhea, which resolved within 10 days but did not result in mortality . The sspA mutant was recovered from bovine intestinal tissues at numbers similar to those obtained for its isogenic parent and caused marked intestinal lesions . Thus, the severity of pathological changes caused by serovar Typhimurium strains or their ability to cause diarrhea were not predictive of their ability to cause lethal morbidity in calves . We conclude that factors other than or in addition to bacterial colonization, intestinal lesions, or electrolyte loss contribute to lethal morbidity in calves infected with serovar Typhimurium.

Infect Immun, 2000 Jun, 68(6), 3147 - 52
Microgravity as a novel environmental signal affecting Salmonella enterica serovar Typhimurium virulence; Nickerson CA et al.; The effects of spaceflight on the infectious disease process have only been studied at the level of the host immune response and indicate a blunting of the immune mechanism in humans and animals . Accordingly, it is necessary to assess potential changes in microbial virulence associated with spaceflight which may impact the probability of in-flight infectious disease . In this study, we investigated the effect of altered gravitational vectors on Salmonella virulence in mice . Salmonella enterica serovar Typhimurium grown under modeled microgravity (MMG) were more virulent and were recovered in higher numbers from the murine spleen and liver following oral infection compared to organisms grown under normal gravity . Furthermore, MMG-grown salmonellae were more resistant to acid stress and macrophage killing and exhibited significant differences in protein synthesis than did normal-gravity-grown cells . Our results indicate that the environment created by simulated microgravity represents a novel environmental regulatory factor of Salmonella virulence.

Infect Immun, 2000 Jun, 68(6), 3129 - 39
Mucosal and systemic immune responses to chimeric fimbriae expressed by Salmonella enterica serovar typhimurium vaccine strains; Chen H et al.; Recombinant live oral vaccines expressing pathogen-derived antigens offer a unique set of attractive properties . Among these are the simplicity of administration, the capacity to induce mucosal and systemic immunity, and the advantage of permitting genetic manipulation for optimal antigen presentation . In this study, the benefit of having a heterologous antigen expressed on the surface of a live vector rather than intracellularly was evaluated . Accordingly, the immune response of mice immunized with a Salmonella enterica serovar Typhimurium vaccine strain expressing the Escherichia coli 987P fimbrial antigen on its surface (Fas(+)) was compared with the expression in the periplasmic compartment (Fas(-)) . Orally immunized BALB/c mice showed that 987P fimbriated Salmonella serovar Typhimurium CS3263 (aroA asd) with pCS151 (fas(+) asd(+)) elicited a significantly higher level of 987P-specific systemic immunoglobulin G (IgG) and mucosal IgA than serovar Typhimurium CS3263 with pCS152 (fasD mutant, asd(+)) expressing 987P periplasmic antigen . Further studies were aimed at determining whether the 987P fimbriae expressed by serovar Typhimurium chi4550 (cya crp asd) could be used as carriers of foreign epitopes . For this, the vaccine strain was genetically engineered to express chimeric fimbriae carrying the transmissible gastroenteritis virus (TGEV) C (379-388) and A (521-531) epitopes of the spike protein inserted into the 987P major fimbrial subunit FasA . BALB/c mice administered orally serovar Typhimurium chi4550 expressing the chimeric fimbriae from the tet promoter in pCS154 (fas(+) asd(+)) produced systemic antibodies against both fimbria and the TGEV C epitope but not against the TGEV A epitope . To improve the immunogenicity of the chimeric fimbriae, the in vivo inducible nirB promoter was inserted into pCS154, upstream of the fas genes, to create pCS155 . In comparison with the previously used vaccine, BALB/c mice immunized orally with serovar Typhimurium chi4550/pCS155 demonstrated significantly higher levels of serum IgG and mucosal IgA against 987P fimbria . Moreover, mucosal IgA against the TGEV C epitope was only detected with serovar Typhimurium chi4550/pCS155 . The induced antibodies also recognized the epitopes in the context of the full-length TGEV spike protein . Hence, immune responses to heterologous chimeric fimbriae on Salmonella vaccine vectors can be optimized by using promoters known to be activated in vivo.

Infect Immun, 2000 Jun, 68(6), 3116 - 20
Effect of preexisting immunity to Salmonella on the immune response to recombinant Salmonella enterica serovar typhimurium expressing a Porphyromonas gingivalis hemagglutinin; Kohler JJ et al.; Recombinant Salmonella strains expressing foreign heterologous genes have been extensively studied as live oral vaccine delivery vectors . We have investigated the mucosal and systemic immune responses following oral immunization with a recombinant Salmonella enterica serovar Typhimurium expressing the hemagglutinin HagB from Porphyromonas gingivalis, a suspected etiological agent of adult periodontal disease . We have previously shown a primary mucosal and systemic response following oral immunization with chi4072/pDMD1 and recall responses following boosting at 14 weeks after primary immunization . In this study, we examined the effects of earlier boosting as well as the effects of deliberately induced immunity to the Salmonella carrier strain on subsequent immune responses . Mice boosted at week 7 following immunization, a point which corresponded to the peak of the primary response, generally showed lower responses than those boosted at week 14 . When mice were preimmunized with the Salmonella carrier alone and then immunized with the recombinant strain 7 or 14 weeks later, significant reductions were seen for serum immunoglobulin G (IgG) antibodies at week 14 and for salivary IgA at week 7 . No reductions were seen in serum IgA or vaginal wash IgA antibodies . Mice appear to be refractory to boosting with orally administered salmonellae at 7 weeks . Deliberate immunization with the carrier strain did not appreciably affect recall responses at 14 weeks, with the exception of the serum IgG responses, nor did it affect colonization of the Peyer's patches.

Infect Immun, 2000 Jun, 68(6), 3079 - 89
Extending the CD4(+) T-cell epitope specificity of the Th1 immune response to an antigen using a Salmonella enterica serovar typhimurium delivery vehicle; Lo-Man R et al.; We analyzed the CD4 T-cell immunodominance of the response to a model antigen (Ag), MalE, when delivered by an attenuated strain of Salmonella enterica serovar Typhimurium (SL3261*pMalE) . Compared to purified MalE Ag administered with adjuvant, the mapping of the peptide-specific proliferative responses showed qualitative differences when we used the Salmonella vehicle . We observed the disappearance of one out of eight MalE peptides' T-cell reactivity upon SL3261*pMalE immunization, but this phenomenon was probably due to a low level of T-cell priming, since it could be overcome by further immunization . The most striking effect of SL3261*pMalE administration was the activation and stimulation of new MalE peptide-specific T-cell responses that were silent after administration of purified Ag with adjuvant . Ag presentation assays performed with MalE-specific T-cell hybridomas showed that infection of Ag-presenting cells by this intracellular attenuated bacterium did not affect the processing and presentation of the different MalE peptides by major histocompatibility complex (MHC) class II molecules and therefore did not account for immunodominance modulation . Thus, immunodominance of the T-cell response to microorganisms is governed not only by the frequency of the available T-cell repertoire or the processing steps in Ag-presenting cells that lead to MHC presentation but also by other parameters probably related to the infectious process and to the bacterial products . Our results indicate that, upon infection by a microorganism, the specificity of the T-cell response induced against its Ags can be much more effective than with purified Ags and that it cannot completely be mimicked by purified Ags administered with adjuvant.

Infect Immun, 2000 Jun, 68(6), 3067 - 73
Salmonella enterica serovar typhi uses type IVB pili to enter human intestinal epithelial cells; Zhang XL et al.; DNA sequencing upstream of the Salmonella enterica serovar Typhi pilV and rci genes previously identified in the ca . 118-kb major pathogenicity island (X.-L . Zhang, C . Morris, and J . Hackett, Gene 202:139-146, 1997) identified a further 10 pil genes apparently forming a pil operon . The product of the pilS gene, prePilS protein (a putative type IVB structural prepilin) was purified, and an anti-prePilS antiserum was raised in mice . Mutants of serovar Typhi either lacking the whole pil operon or with an insertion mutation in the pilS gene were constructed, as was a strain in which the pilN to pilV genes were driven by the tac promoter . The pil(+) strains synthesized type IVB pili, as judged by (i) visualization in the electron microscope of thin pili in culture supernatants of one such strain and (ii) the presence of PilS protein (smaller than the prePilS protein by removal of the leader peptide) on immunoblotting of material pelleted by high-speed centrifugation of either the culture supernatant or sonicates of pil(+) strains . Control pil mutants did not express the PilS protein . A pilS mutant of serovar Typhi entered human intestinal INT407 cells in culture to levels only 5 to 25% of those of the wild-type strain, and serovar Typhi entry was strongly inhibited by soluble prePilS protein (50% inhibition of entry at 1.4 microM prePilS).

Clin Infect Dis, 2000 May, 30(5), 823 - 4
Mycotic aneurysm of the abdominal aorta in a patient undergoing hemodialysis: an unusual complication of Staphylococcus aureus bacteremia; Lee CC et al.; When Staphylococcus aureus is repeatedly positive in blood cultures even under effective antibiotics therapy (vancomycin, teicoplanin, or rifampin), computed tomography scan and sonography should be performed early to exclude mycotic aneurysm of the deeply seated arteries, especially in patients with abdominal aortic calcification . Before 1990, the most common causative organism of suprarenal aortic mycotic aneurysm was Salmonella; since 1990, it has been gram-positive cocci (i.e., Streptococcus and Staphylococcus) rather than gram-negative bacilli (i.e., Salmonella), possibly because of the more invasive procedures performed in clinical settings, but this hypothesis needs further investigation.

Epidemiol Infect, 2000 Apr, 124(2), 185 - 92
Molecular epidemiology of an outbreak caused by Salmonella enterica serovar Newport in Finland and the United Kingdom; Lyytikainen O et al.; Between December 1997 and January 1998 an increase in the number of isolates of Salmonella enterica serovar Newport, a serotype rarely causing indigenous infections in Finland, was detected . This included two clusters of gastroenteritis following funeral meals . An inquiry via Enter-net revealed a concomitant increase in cases of S . Newport in the United Kingdom . To investigate the Finnish outbreak, a total of 56 S . Newport strains (22 from the outbreak period, 27 from pre- and post-outbreak period, and 7 from imported food producing animals) were studied by pulsed-field gel electrophoresis (PFGE); selected isolates were also phage typed . Two retrospective questionnaire studies evaluating food exposures among the funeral attendants were conducted . All isolates from the clusters had an identical PFGE pattern which was also found in 13 infections temporally close to but not associated with the clusters . The Finnish outbreak was caused by the same phage type as the one in the United Kingdom . In both clusters, an epidemiological link between illness and exposure to cured ham was found . In conclusion, the outbreak was not limited to the two clusters but was more widely spread both in and outside Finland . Early alarm systems of food-borne outbreaks and collaboration between European countries are needed for investigating international outbreaks.

Adv Exp Med Biol, 2000, 465, 57 - 63
Tumor-targeted Salmonella . Highly selective delivery vectors; Bermudes D et al.; Genetically engineered Salmonella offer an intriguing new approach to selectively target solid tumors, including melanoma, lung, colon, breast, kidney and liver . These bacteria target tumors after systemic administration and selectively replicate within them . Specificity for tumors is often more than 1,000 times greater than for any other tissue . Auxotrophic mutations make these bacteria highly safe and form the basis for maintaining tumor specificity . An altered lipid greatly reduces the potential for septic shock yet also retains the antitumor properties of these bacteria . These bacteria have innate antitumor activity towards both primary and metastatic tumors and the ability to deliver proteins capable of activating chemotherapeutic agents directly within tumors . The delay in tumor growth results in mice that survive up to twice as long . These bacteria are susceptible to a wide range of antibiotics, allowing external control of the vector after administration . The combination of these features within a single vector seems specially surprising considering their unlikely source.

J Commun Dis, 1999 Mar, 31(1), 29 - 34
Typhoid fever caused by a typical variants of Salmonella typhi--a preliminary report; Ranjitham M et al.; In the study carried out from, February, 1996 to January, 1999 . 42 (33.9%) a typical variants of S typhi which fermented sucrose were encountered . This variant was identified as of antigenic structure 9, 12, v1, d1 and typed as phage type E1 and Bio type I.

J Commun Dis, 1998 Dec, 30(4), 279 - 82
Prevalance and resistance pattern of Salmonella serotypes in India; Mahajan R et al.; During the period 1990-91, 3222 Salmonella strains were identified at the National Salmonella and Escherichia Centre (NSEC) at Central Research Institute, Kasauli . Of these, 2894 were from humans, 226 from poultry, 84 from animals and remaining 18 from reptiles, birds and other sources . These strains belonged to 53 different serotypes . These include 4 serotypes reported for the first time in India, namely S . kedogou, S . VP . bornheim, S . kisarawe and S . madras . Drug resistance studies revealed that 573 strains were sensitive to all the antibiotics commonly used, 1351 single drug resistant, 594 resistant to two drugs and 704 were multidrug resistant . One strain from human stool was resistant to all the antibiotics used . Prevalence of various Salmonella serotypes and their response to various drugs is discussed.

Biochem Pharmacol, 2000 Jan 15, 59(2), 203 - 9
Role of nitric oxide in lipopolysaccharide-induced oxidant stress in the rat kidney; Zhang C et al.; Lipopolysaccharide (LPS)-induced renal oxidant injury and the role of nitric oxide (NO) were evaluated using the inducible nitric oxide synthase (iNOS) inhibitor L-iminoethyl-lysine (L-NIL) . One group of male rats received LPS (Salmonella minnesota; 2 mg/kg, i.v.) . A second group received LPS plus L-NIL (3 mg/kg, i.p.) . A third group received saline i.v . At 6 hr, iNOS protein was induced in the kidney cortex, and plasma nitrate/nitrite levels were increased from 4 +/- 2 nmol/mL in the Saline group to 431 +/- 23 nmol/mL in the LPS group . The value for the LPS + L-NIL group was reduced significantly to 42 +/- 9 nmol/mL . LPS increased blood urea nitrogen levels from 13 +/- 1 to 47 +/- 3 mg/dL . LPS + L-NIL reduced these levels significantly to 29 +/- 2 mg/dL . Plasma creatinine levels were unchanged in all groups . Tissue lipid peroxidation products in the kidney were increased from 0.16 +/- 0.01 nmol/mg in the Saline group to 0.30 +/- 0.03 nmol/mg in the LPS group . LPS + L-NIL reduced the values significantly to 0.22 +/- 0.02 nmol/mg . Intracellular glutathione levels were decreased in the kidneys from 1.32 +/- 0.1 nmol/mg in the Saline group to 0.66 +/- 0.08 nmol/mg in the LPS group . LPS + L-NIL increased the levels significantly to 0.99 +/- 0.13 nmol/mg . LPS increased the 3-nitrotyrosine-protein adducts in renal tubules as detected by immunohistochemistry, indicating the generation of peroxynitrite . L-NIL decreased adduct formation . These data indicated that LPS-induced NO generation resulted in peroxynitrite formation and oxidant stress in the kidney and that inhibitors of iNOS may offer protection against LPS-induced renal toxicity.

J Bacteriol, 2000 Jun, 182(11), 3125 - 35
Sequence diversity of Pseudomonas aeruginosa: impact on population structure and genome evolution; Kiewitz C et al.; Comparative sequencing of Pseudomonas aeruginosa genes oriC, citS, ampC, oprI, fliC, and pilA in 19 environmental and clinical isolates revealed the sequence diversity to be about 1 order of magnitude lower than in comparable housekeeping genes of Salmonella . In contrast to the low nucleotide substitution rate, the frequency of recombination among different P . aeruginosa genotypes was high, leading to the random association of alleles . The P . aeruginosa population consists of equivalent genotypes that form a net-like population structure . However, each genotype represents a cluster of closely related strains which retain their sequence signature in the conserved gene pool and carry a set of genotype-specific DNA blocks . The codon adaptation index, a quantitative measure of synonymous codon bias of genes, was found to be consistently high in the P . aeruginosa genome irrespective of the metabolic category and the abundance of the encoded gene product . Such uniformly high codon adaptation indices of 0.55 to 0.85 fit the ubiquitous lifestyle of P . aeruginosa.

J Bacteriol, 2000 Jun, 182(11), 3029 - 36
Interaction between FliE and FlgB, a proximal rod component of the flagellar basal body of Salmonella; Minamino T et al.; FliE is a flagellar basal body protein of Salmonella whose detailed location and function have not been established . A mutant allele of fliE, which caused extremely poor flagellation and swarming, generated extragenic suppressors, all of which mapped to flgB, one of four genes encoding the basal body rod; the fliE flgB pseudorevertants were better flagellated and swarmed better than the fliE parent, especially when the temperature was reduced from 37 to 30 degrees C . Motility of the pseudorevertants in liquid culture was markedly better than motility on swarm plates; we interpret this to mean that reduced flagellation is less deleterious at low viscous loads . Overproduction of the mutant FliE protein improved the motility of the parental fliE mutant and its pseudorevertants, though not to wild-type levels . Overproduction of suppressor FlgB (but not wild-type FlgB) in the fliE mutant also resulted in improved motility . The second-site FlgB mutation by itself had no phenotype; cells swarmed as well as wild-type cells . When overproduced, wild-type FliE was dominant over FliE-V99G, but the reverse was not true; that is, overproduced FliE-V99G was not negatively dominant over wild-type FliE . We conclude that the mutant protein has reduced probability of assembly but, if assembled, functions relatively well . Export of the flagellar protein FlgD, which is known to be FliE dependent, was severely impaired by the FliE-V99G mutation but was significantly improved in the suppressor strains . The FliE mutation, V99G, was close to the C terminus of the 104-amino-acid sequence; the suppressing mutations in FlgB were all either G119E or G129D, close to the C terminus of its 138-amino-acid sequence . Affinity blotting experiments between FliE as probe and various basal body proteins as targets and vice versa revealed strong interactions between FliE and FlgB; much weaker interactions between FliE and other rod proteins were observed and probably derive from the known similarities among these proteins . We suggest that FliE subunits constitute a junction zone between the MS ring and the rod and also that the proximal rod structure consists of FlgB subunits.

J Bacteriol, 2000 Jun, 182(11), 3022 - 8
Deletion analysis of the flagellar switch protein FliG of Salmonella; Kihara M et al.; The flagellar motor/switch complex, consisting of the three proteins FliG, FliM, and FliN, plays a central role in bacterial motility and chemotaxis . We have analyzed FliG, using 10-amino-acid deletions throughout the protein and testing the deletion clones for their motility and dominance properties and for interaction of the deletion proteins with the MS ring protein FliF . Only the N-terminal 46 amino acids of FliG (segments 1 to 4) were important for binding to FliF; consistent with this, an N-terminal fragment consisting of residues 1 to 108 bound FliF strongly, whereas a C-terminal fragment consisting of residues 109 to 331 did not bind FliF at all . Deletions in the region from residues 37 to 96 (segments 4 to 9), 297 to 306 (segment 30), and 317 to 326 (segment 32) permitted swarming, though not at wild-type levels; all other deletions caused paralyzed or, more commonly, nonflagellate phenotype . Except for those near the N terminus, deletions had a dominant negative effect on wild-type cells.

Zh Mikrobiol Epidemiol Immunobiol, 2000 Mar-Apr, (2), 22 - 5
{A comparison of the yield of Vi and O antigens during the adaptation of Salmonella typhi strains to cultivation under starvation conditions}; Basnak'ian IA et al.; S . typhi strains Ty(2)4446 and Vi-1S underwent multiple passages in f synthetic liquid starvation culture medium consisting of water with salts and glucose added . In the process of the adaptation of the cultures to these stress conditions (starvation stress) the increasing yield of biomass from passage to passage was observed . Differences in the accumulation of Vi- and O-antigens were noted in two strains under study . In the cultures of strain Ty(2)4446 an insignificant increase in the antigen content from passage to passage was observed, while in the cultures of strain Vi-1S an increase in the content of Vi- and O-antigens was 4- to 5-fold . With the adaptation of the culture the Vi-antigen to O-antigen ratio changed from 1:57 to 1:20 for strain Ty(2)4446 and from 1:2.7 tp 1:2.2 for strain Vi-1S . Strain Ty(2)4446 had an advantage over strain Vi-1S with respect to the synthesis of Vi-antigen . These data are indicative of the expediency of using not only strain Ty(2)4446, but also strain Vi-1S for the preparation of typhoid vaccine, especially the one based on Vi-antigen.

Vet Microbiol, 2000 Jun 1, 74(3), 259 - 72
Adsorption of Salmonella enteritidis by cetylpyridinium-exchanged montmorillonite clays; Herrera P et al.; Recent experiments in our laboratory have suggested that certain montmorillonite clays, when exchanged with the cationic surfactant cetylpyridinium (CP), may be useful in removing bacteria from aqueous solution . During an initial study, screening various CP-exchanged products for potential antibacterial activity, three CP-exchanged clays - CP*AAM (acid-activated montmorillonite), CP*STx-1 (Ca(++)-montmorillonite), and CP*SWy-2 (Na(+)-montmorillonite), proved to be the most effective . Binding studies were performed using 1mg each of CP-exchanged AAM, STx-1, and SWy-2 with a standardized Salmonella enteritidis solution containing approximately 40,000 colony forming units (CFU)/ml . The modified clays reduced bacterial numbers 98.1, 97.6, and 95.2%, respectively . In contrast, the parent clays only produced reductions of 39.8, 16.9, and 16.6%, respectively . Attempts were made to desorb CP from the modified clays by washing in sterile physiological saline for 24h . The resulting wash solutions failed to produce any significant reduction in bacterial colony counts; while, the washed clays retained their full antimicrobial activity . These findings suggested that the antibacterial effect of the clays is localized on the clay surface and is not due to CP dissociating from the clay . Electron microscopy revealed that the bacteria adhered to the surface of the CP-exchanged clays, but not the parent clays . Results from timed binding studies showed that the antibacterial effect was stable over the period observed . Rates of binding were positively influenced by increasing temperature, not affected by changes in pH, and negatively influenced by the presence of organic contaminants . The mechanism by which bacterial counts are reduced may involve the enhanced hydrophobicity and affinity of the CP-exchanged clay for Salmonella and the antibacterial activity of CP.

Vet Microbiol, 2000 Jun 1, 74(3), 217 - 25
Subdivision of Salmonella enterica serovar enteritidis phage types PT14b and PT21 by plasmid profiling; Rychlik I et al.; We have shown that plasmid profiling is a sensitive method for further identification of strains of Salmonella enterica serovar enteritidis (S . enteritidis) phage type PT21 and to a lesser extent the strains of phage type PT14b . Five and three plasmid types were identified within 33 strains of phage type PT21 and 19 strains of phage type PT14b, respectively . Plasmid types in strains of phage type PT21 showed significant correlation with geographical origin of the strain . In strains of phage type PT14b a single isolate predominated suggesting that the plasmid designated as 'C' can be directly linked with S . enteritidis PT14b strains . Application of IS200 fingerprinting did not reveal any other differences and showed just one copy of IS200 in all the 52 analysed strains . All the strains were tested for antibiotic resistance and only four strains were resistant to ampicillin, cefotaxime, cefuroxime and cotrimoxazole . This indicates that low molecular weight plasmids in Salmonella enteritidis are not responsible for the spread of antibiotic resistance.

J Biol Chem, 2000 Jul 28, 275(30), 22948 - 54
The phosphatase activity is the target for Mg2+ regulation of the sensor protein PhoQ in Salmonella; Castelli ME et al.; The PhoP/PhoQ two-component system controls the expression of essential virulence traits in the pathogenic bacterium Salmonella enterica serovar Typhimurium . Environmental deprivation of Mg(2+) activates the PhoP/PhoQ signal transduction cascade, which results in an increased expression of genes necessary for survival inside the host . It was previously demonstrated that the interaction of Mg(2+) with the periplasmic domain of PhoQ promotes a conformational change in the sensor protein that leads to the down-regulation of PhoP-activated genes . We have now examined the regulatory effect of Mg(2+) on the putative activities of the membrane-bound PhoQ . We demonstrated that Mg(2+) promotes a phospho-PhoP phosphatase activity in the sensor protein . This activity depends on the intactness of the conserved His-277, suggesting that the phosphatase active site overlaps the H box . The integrity of the N-terminal domain of PhoQ was essential for the induction of the phosphatase activity, because Mg(2+) did not stimulate the release of inorganic phosphate from phospho-PhoP in a fusion protein that lacks this sensing domain . These findings reveal that the sensor PhoQ harbors a phospho-PhoP phosphatase activity, and that this phosphatase activity is the target of the extracellular Mg(2+)-triggered regulation of the PhoP/PhoQ system.

J Microbiol Immunol Infect, 2000 Mar, 33(1), 39 - 44
An outbreak of Salmonella infection after a Chinese year-end party in central Taiwan; Hwang KL et al.; An outbreak of food poisoning caused by Salmonella O7 serogroup C1 and O8 serogroup C2, occurred in Taichung City after a Chinese year-end buffet party with 127 attendees including employees, relatives and guests of the Psychiatry Department of Changhua Christian Hospital (CCH) . Among the 114 attendees interviewed, 96 (84.2%) reported developing symptoms within 120 h after the dinner on February 4, 1999 . The time of onset ranged from 2 h to 101 h after the dinner with an average of 20 +/- 16 h . The median and mode incubation periods were 17 h and 16 h, respectively . Salmonella C1 and C2 serogroups were isolated from the stool samples of 45 attendees . Based on the results of interview questionnaire, the most likely contaminated food was eel kabayaki (OR = 4.8, 95% CI:1.6-14.9, p < 0.01) followed by baked mussels (OR = 4.04, 95% CI:1.3-12.1, p = 0.01) . However, this result could not be confirmed by food sample investigation due to the lack of leftover food . Possible techniques for the prevention of food-borne disease transmission, enhancement of communication about foodborne disease outbreaks within the health reporting system, and the reduction of response time during an outbreak of infection are required.

Med Dosw Mikrobiol, 1999, 51(3-4), 281 - 8
{Use of WARD et al's scheme for bacteriophage typing of Salmonella enteritidis strains isolated in Poland}; Dera-Tomaszewska B et al.; The typing phages set of Ward et al . was used to type a total of 517 strains of Salmonella Enteritidis isolated in Poland in 1986-1995 . According to the Ward et al . scheme, 56.5% of the strains tested were assigned to 14 different phage types . Phage types 8, 4, 1 and 4a were placed first, second, third and fourth, respectively . They were dominated both in the outbreak isolates and in the isolates from the other sources . Ten phage types were represented by single strains . Other strains reacted with phages without showing any of the designated phage type (37.1%) or were untypable (6.4%) . The Ward et al . scheme seems to demonstrate not enough high degree of strain discrimination for Salmonella Enteritidis isolates in Poland . It seems that the Ward et al . scheme is not enough useful for the epidemiological investigations of Salmonella Enteritidis in Poland.

Nat Struct Biol, 2000 May, 7(5), 398 - 402
RmlC, the third enzyme of dTDP-L-rhamnose pathway, is a new class of epimerase; Giraud MF et al.; Deoxythymidine diphosphate (dTDP)-L-rhamnose is the precursor of L-rhamnose, a saccharide required for the virulence of some pathogenic bacteria . dTDP-L-rhamnose is synthesized from glucose-1-phosphate and deoxythymidine triphosphate (dTTP) via a pathway involving four distinct enzymes . This pathway does not exist in humans and the enzymes involved in dTDP-L-rhamnose synthesis are potential targets for the design of new therapeutic agents . Here, the crystal structure of dTDP-6-deoxy-D-xylo-4-hexulose 3,5 epimerase (RmlC, EC5.1.3.13) from Salmonella enterica serovar Typhimurium was determined . The third enzyme of the rhamnose biosynthetic pathway, RmlC epimerizes at two carbon centers, the 3 and 5 positions of the sugar ring . The structure was determined by multiwavelength anomalous diffraction to a resolution of 2.17 A . RmlC is a dimer and each monomer is formed mainly from two beta-sheets arranged in a beta-sandwich . The structure of a dTDP-phenol-RmlC complex shows the substrate-binding site to be located between the two beta-sheets; this site is formed from residues of both monomers . Sequence alignments of other RmlC enzymes confirm that this region is very highly conserved . The enzyme is distinct structurally from other epimerases known and thus, is the first example of a new class of carbohydrate epimerase.

Przegl Epidemiol, 1999, 53(3-4), 365 - 9
{Salmonella serovars determined in the National Salmonella Center between 1995 and 1997}; Dera-Tomaszewska B et al.; A total of 897 human and non-human (from animal, food, feed and other sources) isolates of Salmonella were serotyped in the National Salmonella Centre during the period 1995-1997 . They had been referred to the Centre by several field laboratories all over the country . Serological and biochemical identification was performed according to the standard methods . Forty seven Salmonella serovars were isolated from human sources . The most common Salmonella serovars were S . Thompson, S . Mbandaka and S . Enteritidis . The other were S . Hadar, S . Infantis, S . Albany, S . Typhimurium and S . Virchow . The serovars isolated from the food products were almost the same as from human sources . A total of 37 Salmonella serovars were found in isolates from animal sources . The dominating serovars were S . Enteritidis, S . Mbandaka, S . Bredeney, S . Infantis, S . Anatum, S . Typhimurium, S . Hadar, S . Saintpaul, S . Agona, S . Virchow, S . Heidelberg and S . Thompson . The fact that a number of the same serovars were found on lists of the most commonly isolated serovars from human and animal sources underlines the importance of the relationship . The lack of information of Salmonella contaminated food products and animal infections was noticed More detail examination of isolates from animal sources is advised to help the fight against human salmonellosis.

Przegl Epidemiol, 1999, 53(3-4), 355 - 64
{Salmonella serovars defined in Poland}; Dera-Tomaszewska B et al.; One hundred and sixty nine serovars of Salmonella, belonging to 28 different O groups, were defined in the National Salmonella Centre . All the serovars were isolated in Poland . Above 70% (121/169) of them belonged to five O groups--O:4 (31 serovars), O:7 (28 serovars), O:8 (27 serovars), O:3,10 (20 serovars) and O:9 (15 serovars) . Other O groups were represented by some (1 to 8) serovars . All the serovars were described according to the changes in taxonomy of the genus Salmonella and in serovars nomenclature . These changes, proposed by WHO Collaborating Centre for Reference and Research on Salmonella (Paris, France), reflect the recent advances in Salmonella taxonomy.

J Biol Chem, 2000 May 12, 275(19), 14084 - 94
Analysis by high density cDNA arrays of altered gene expression in human intestinal epithelial cells in response to infection with the invasive enteric bacteria Salmonella; Eckmann L et al.; Many clinically important enteric pathogens initiate disease by invading and passing through the intestinal epithelium, a process accompanied by increased epithelial expression of proinflammatory cytokines . To further define the role intestinal epithelial cells play in initiating and modulating the host response to infection with invasive bacteria, hybrid selection on high density cDNA arrays was used to characterize the mRNA expression profile of approximately 4,300 genes in human intestinal epithelial cells after infection with the prototypic invasive bacteria, Salmonella . Selected findings were further evaluated by reverse transcription-polymerase chain reaction, Northern blot analysis, and protein assays . Epithelial infection with Salmonella significantly up-regulated mRNA expression of a relatively small fraction of all genes tested . Of these, several cytokines (granulocyte colony-stimulating factor, inhibin A, Epstein-Barr virus-induced gene 3, interleukin-8, macrophage inflammatory protein-2alpha), kinases (TKT, Eck, HEK), transcription factors (interferon regulatory factor-1), and HLA class I were the most prominent . Furthermore, the transcription factor NF-kappaB is shown to be important for inducible mRNA expression for a broad group of genes tested . These findings expand the repertoire of known epithelial cell responses to infection with an invasive enteric pathogen . The results also show that evaluation of mRNA expression profiles by cDNA array analysis is a powerful approach to characterizing and understanding host-pathogen interactions.

J Med Microbiol, 2000 May, 49(5), 481 - 7
The role of SEF14 and SEF17 fimbriae in the adherence of Salmonella enterica serotype Enteritidis to inanimate surfaces; Woodward MJ et al.; To gain an understanding of the role of fimbriae and flagella in the adherence of Salmonella enterica serotype Enteritidis to inanimate surfaces, the extent of adherence of viable wild-type strains to a polystyrene microtitration plate was determined by a crystal violet staining assay . Elaboration of surface antigens by adherent bacteria was assayed by fimbriae- and flagella-specific ELISAs . Wild-type Enteritidis strains adhered well at 37 degrees C and 25 degrees C when grown in microtitration wells in Colonisation Factor Antigen broth, but not in other media tested . At 37 degrees C, adherent bacteria elaborated copious quantities of SEF14 fimbrial antigen, whereas at 25 degrees C adherent bacteria elaborated copious quantities of SEF17 fimbrial antigen . Non-fimbriate and non-flagellate knock-out mutant strains were also assessed in the adherence assay . Mutant strains unable to elaborate SEF14 and SEF17 fimbriae adhered poorly at 37 degrees C and 25 degrees C, respectively, but adherence was not abolished . Non-motile mutant strains showed reduced adherence whilst type-1, PEF and LPF fimbriae appeared not to contribute to adherence in this assay . These data indicate that SEF17 and SEF14 fimbriae mediate bacterial cell aggregation on inanimate surfaces under appropriate growth conditions.

Indian J Med Sci, 1999 Jan, 53(1), 7 - 9
Salmonella typhi VI antigen co-agglutination test for the rapid diagnosis of typhoid fever; Rao PS et al.; A slide Co-agglutination test for the detection of Salmonella typhi Vi antigen in blood was evaluated for its efficiency in rapid diagnosis of Typhoid fever . The results were compared with conventional methods like Blood culture and Widal test . The test showed a sensitivity of 86.67% and specificity of 88.83% when compared with blood culture positivity or Widal titre above 160 . This is a useful rapid diagnostic test for the early diagnosis of Typhoid fever.

Dakar Med, 1999, 44(1), 40 - 4
{Contribution of medical imaging in osteoarticular manifestations of sickle cell anemia in the child}; Cisse R et al.; Drepanocytosis is one of the qualitative hemoglobinopathies which are the most widespread in the word . In a retrospective study on 16 drepanocytary patients observed at the Bordeaux Children's hospital, 7 patients showed medullar hyperplasia, 10 patients showed vaso-occlusive, and 4 patients showed infections . Medullar hyperplasia: bone demineralisation was the current appearance (47%), cortical thinning down (40.5%) . They touch long bone . Thrombosis: bone demineralisation was the current appearance (86.3%) and touch long bone, 1 first appearance right femoral head infarct . Some particular appearances we found . 2 cases of "hand foot syndrome", 1 case ischemic aseptic arthritis and 1 case of vertebra "step staircase" . Three salmonella pandiaphysite and 1 tuberculosis spondylodiscite were observed . The authors analyse the major radiological appearances of this hemoglobinopathy and recall the interest in knowing this disease even in low endemicity countries.

Cochrane Database Syst Rev . 2000;(2):CD001261.
Vaccines for preventing typhoid fever; Engels EA et al.; BACKGROUND: Whole cell vaccines, consisting of relatively crude preparations of Salmonella typhi administered parenterally, are effective but have a high incidence of adverse effects . Two vaccines have been developed more recently . Ty21a (an attenuated strain of S . typhi administered orally) and Vi (the purified bacterial capsule, given parenterally), have appeared less toxic than the older whole cell vaccines and are thought to be equally effective . OBJECTIVES: The objective of this review was to assess the effects of typhoid fever vaccines . SEARCH STRATEGY: We searched the Cochrane Library, Medline, Index Medicus, Embase and reference lists of articles . SELECTION CRITERIA: Randomised trials comparing typhoid vaccines to other types of vaccine or placebo . DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality and extracted data . MAIN RESULTS: Seventeen studies, involving nearly two million people, were included . For the whole cell vaccines single dose regimens provided significant protection for the first two years . Two dose regimens provided significant protection for five years . For the Ty21a vaccine, both two and three dose regimens provided statistically significant protection for two years . The three dose regimen provided protection in the third and fourth years, but protection was not statistically significant in the fifth year . The Vi vaccine provided protection for two years, but the protection in the third year was not significant . The three year cumulative efficacy of two doses of whole cell vaccines was 73% (95% confidence interval 65-80), three doses of Ty21a was 51%, (95% confidence interval 35 to 63) and one dose of Vi was 55% (95% confidence interval 30 to 71) . Data on adverse effects were limited, but indicate that whole cell vaccines are more toxic than the newer Ty21a and Vi vaccines . REVIEWER'S CONCLUSIONS: The whole cell vaccines provided more prolonged protection than either the Ty21a vaccine or the Vi vaccine . However whole cell vaccines are associated with higher toxicity.

Cochrane Database Syst Rev . 2000;(2):CD001167.
Antibiotics for treating salmonella gut infections; Sirinavin S et al.; BACKGROUND: Antibiotic treatment of salmonella infections aims to shorten illness and prevent serious complications . There are also concerns about increasing antibiotic drug resistance . OBJECTIVES: The objective of this review was to assess the effects of antibiotics in adults and children with diarrhoea who have salmonella . SEARCH STRATEGY: We searched the Cochrane Infectious Diseases Group trials register, the Cochrane Controlled Trials Register, Medline, Science Citation Index, African Index Medicus, Lilacs, Extra Med and reference lists of relevant articles . We also contacted experts in the field . SELECTION CRITERIA: Randomised and quasi-randomised trials comparing antibiotic therapy with placebo or no antibiotic therapy for salmonella infections in symptomatic or asymptomatic adults or children . Typhoid and paratyphoid salmonella infections were excluded . DATA COLLECTION AND ANALYSIS: Trial quality assessment and data were extracted independently by two reviewers . MAIN RESULTS: Twelve trials involving 778 participants (with at least 258 infants and children) were included . There were no significant differences in length of illness, diarrhoea or fever between any antibiotic regimen and placebo . The weighted mean difference for length of illness was -0.07 days, 95% confidence interval -0.55 to 0.40; diarrhoea -0.03 days, 95% confidence interval -0.53 to 0.48; fever -0.45 days, 95% confidence interval -0 . 98 to 0.08 . Antibiotic regimens resulted in more negative cultures during the first week of treatment . Relapses were more frequent in those receiving antibiotics, and there were more cases with positive cultures in the antibiotic groups after three weeks . Adverse drug reactions were more common in the antibiotic groups (odds ratio 1.67, 95% confidence interval 1.05 to 2.67) . REVIEWER'S CONCLUSIONS: There appears to be no evidence of a clinical benefit of antibiotic therapy in otherwise healthy children and adults with non-severe salmonella diarrhoea . Antibiotics appear to increase adverse effects and they also tend to prolong salmonella detection in stools.

Dig Dis Sci, 2000 May, 45(5), 900 - 3
Carcinoma of the gallbladder--is it a sequel of typhoid?
Shukla VK, Singh H, Pandey M, Upadhyay SK, Nath G.
Gallbladder diseases, including carcinoma, are common in the northern part of India and so are Salmonella typhi infection and typhoid carrier state . This study was aimed to find out the association of typhoid carrier state in patients with cholelithiasis, carcinoma of the gallbladder, and controls . The three groups are comparable in age and sex composition . This is the first study of its kind from an area of high endemicity for both typhoid infection and carcinoma of the gallbladder . A case-control study was carried out to detect typhoid carrier state among the patients with biliary diseases and healthy controls, using indirect haemagglutination assay measuring antibodies against highly purified S . typhi Vi polysaccharide antigen . A significantly high Vi positivity was observed in patients with gallbladder carcinoma (29.4%) compared to controls (5%) (chi2 = 6.325, P < 0.004, OR = 7.19) and patients with cholelithiasis (10.7%) (chi2 = 5.066, P < 0.01, OR = 3.86) . There is 8.47 times more risk of developing carcinoma of the gallbladder in culture-positive typhoid carriers than the noncarriers . The present study suggests the typhoid carrier state to be one of the possible mechanisms of gallbladder carcinogenesis.

Int J Antimicrob Agents, 2000 May, 14(4), 285 - 90
Antibiotic resistance monitoring: the Spanish programme . The VAV Network . Red de Vigilancia de Resistencias Antibióticas en Bacterias de Origen Veterinario; Moreno MA et al.; Antimicrobial resistance is a problem in modern public health and antimicrobial use and especially misuse, the most important selecting force for bacterial antibiotic resistance . As this resistance must be monitored we have designed the Spanish network 'Red de Vigilancia de Resistencias Antibioticas en Bacterias de Origen Veterinario' . This network covers the three critical points of veterinary responsibility, bacteria from sick animals, bacteria from healthy animals and bacteria from food animals . Key bacteria, antimicrobials and animal species have been defined for each of these groups along with laboratory methods for testing antimicrobial susceptibility and for data analysis and reporting . Surveillance of sick animals was first implemented using Escherichia coli as the sentinel bacterium . Surveillance of E . coli and Enterococcus faecium from healthy pigs was implemented in 1998 . In July 1999, data collection on Salmonella spp . was initiated in poultry slaughterhouses . Additionally, the prevalence of vancomycin resistant E . faecium was also monitored . This network has specific topics of interest related to methods of determining resistance, analysis and reporting of data, methods of use for veterinary practitioners and collaboration with public health authorities.

Int J Antimicrob Agents, 2000 May, 14(4), 275 - 83
The French antibiotic resistance monitoring programs; Martel JL et al.; Surveillance of antimicrobial resistance in bacteria from animal origin in France is organised by the French Agency for Food Safety (Agence Francaise de Securite Sanitaire des Aliments, AFSSA) through two types of networks . The first collects non-human zoonotic Salmonella strains in one centre (AFSSA, Paris) where they are tested for their antimicrobial susceptibility . The others, managed by AFSSA Lyon, deal with bovine pathogenic strains and are multicentric, that is they collecting antibiotic sensitivity and other data from the local public veterinary diagnostic laboratories . This requires standardisation of the methods used in each partner laboratory . Statistical analysis of any change in French resistance patterns can be monitored by these three networks either as a function of strain pathogenicity and/or of the ecological origin of the isolate . The system also encourages efficient collaboration between veterinarians and the laboratory . Such collaboration improves both the quality of routine antibiotic testing and understanding of the molecular mechanisms underlying resistance.

Mol Microbiol, 2000 Apr, 36(2), 498 - 507
The use of listeriolysin to identify in vivo induced genes in the gram-positive intracellular pathogen Listeria monocytogenes; Gahan CG et al.; Listeria monocytogenes is capable of growth within the cytoplasm of infected host cells . Escape from the host cell phagosome is mediated primarily through secretion of listeriolysin, a haemolytic factor which functions to actively lyse the phagosomal membrane . Listeriolysin negative mutants of L . monocytogenes are non-haemolytic on blood agar plates and demonstrate a significant reduction of virulence in the mouse model of infection . We have developed a system for the identification of in vivo induced genes in L . monocytogenes which utilizes the listeriolysin gene, hly, as both a reporter of gene expression and as a means of selection of promoter elements expressed in vivo . The system is analogous to in vivo expression technology (IVET) first reported for Salmonella, however, as listeriolysin functions in the environment of the host phagosome the loci identified in this study are most likely expressed during residence in the phagosome . The system was successfully tested using the promoter of the inducible virulence gene plcA . A bank was created by fusing a promoterless copy of hly to random promoter elements in a listeriolysin negative IVET host . Sequential inoculations of mice with this bank resulted in the isolation of clones with increased survival potential in the mouse model relative to a negative control, but which remained haemolysin negative on blood agar plates . Nine in vivo induced loci were identified including genes encoding a DNA topoisomerase III, a cellobiose transporter and a fumarase . Two isolates represented fusions to proteins of unknown function and three isolates contained no significant homologues in the database . A mutant in the fumarase gene demonstrated reduced virulence for mice and an inability to grow in cultured mouse phagocytes.

Lett Appl Microbiol, 2000 Apr, 30(4), 267 - 71
Probeliatrade mark PCR system for rapid detection of Salmonella in milk powder and ricotta cheese; Wan J et al.; The Probeliatrade mark Salmonella sp . PCR amplification and detection kits (Sanofi Diagnostics Pasteur, Marnes La Coquette, France) were evaluated for the rapid and specific detection of Salmonella agona artificially inoculated into skim milk powder and ricotta cheese . The Probeliatrade mark results were compared with those obtained using the Australian Standard Method . Using a pure culture of Salm . agona, the detection limit of Probeliatrade mark was between 8 and 79 cfu ml-1, equivalent to 0.2-2 cfu per PCR reaction . Detection of Salm . agona inoculated in skim milk powder (at 5-10 cfu g-1, stored at 5, 15 or 25 degrees C) and ricotta cheese (at 1-2, 10-20 and 100-200 cfu per 25 g) was effected by using non-selective enrichment prior to the PCR determinations . For all of the 40 milk powder samples and 12 ricotta cheese samples, the Probeliatrade mark results were consistent with those using the Australian Standard Method . Using Probeliatrade mark, Salmonella was detected to genus level in the dairy products within 24-28 h, whereas the cultural technique required 3-4 d for presumptive positive isolates and further time for confirmation.

Am J Vet Res, 1999 Oct, 60(10), 1201 - 6
Effects of the antimicrobial growth promoter tylosin on subclinical infection of pigs with Salmonella enterica serotype Typhimurium; Baggesen DL et al.; OBJECTIVE: To determine whether feeding tylosin, an antimicrobial growth promoter, to pigs was associated with increased risk of infection with and excretion of Salmonella enterica serotype Typhimurium . ANIMALS: 17 healthy pigs . PROCEDURE: A commercial pelleted dry feed was given in 2 feeding trials . In trial A, 11 pigs were given feed with tylosin, 11 pigs were given feed without tylosin, and 11 pigs were given feed with tylosin before and feed without tylosin after inoculation with S Typhimurium . In trial B, 44 pigs were given feed that contained tylosin, and 44 pigs were given feed without tylosin . Three weeks after the start of each trial, pigs were orally inoculated with approximately 5 x 10(6) colony-forming units of S Typhimurium . Feces were examined for S Typhimurium, using semiquantitative microbiologic techniques before and for 5 or 6 weeks after inoculation . Serum antibody titers against S enterica were measured by use of ELISA . RESULTS: None of the pigs developed clinical signs of salmonellosis . However, after inoculation, S Typhimurium was isolated from feces of most pigs, and all but 2 pigs developed serum antibodies against S enterica . Significant differences were not detected between experimental and control groups in either trial . CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that tylosin fed as an antimicrobial growth promoter to pigs may not be an important factor in promoting infection with or excretion of S enterica serotype Typhimurium.

Int J Food Microbiol, 2000 Apr 10, 55(1-3), 143 - 6
Influence of different factors on the inactivation of Salmonella senftenberg by pulsed electric fields; Alvarez I et al.; The influence of growth phase, cell concentration, pH and conductivity of treatment medium on the inactivation of Salmonella senftenberg by high electric field pulses (HELP) was studied . Cells were more resistant to HELP treatments at the beginning of the logarithmic phase and at the stationary phase . Microbial inactivation was not a function of the initial cell concentration . At constant input voltage, electric field strength obtained in the treatment chamber depended on medium conductivity . At the same electric field strength, conductivity did not influence S . senftenberg inactivation . At the same conductivity, inactivation of S . senftenberg was bigger at neutral than acidic pH.

Genes Genet Syst, 1999 Dec, 74(6), 287 - 92
Two novel regulatory genes, fliT and fliZ, in the flagellar regulon of Salmonella; Kutsukake K et al.; The flagellar operons of Salmonella are divided into three classes with respect to their transcriptional hierarchy . Expression of the class 2 operons requires the class 1 gene products, FlhD and FlhC, and is increased by mutation in the flgM gene, which encodes a class 3-specific anti-sigma factor . Here we report the identification of two novel regulatory genes for class 2 transcription . Presence of the fliZ and fliT genes on multicopy plasmids enhanced and inhibited, respectively, transcription from a chromosomal class 2 promoter . Disruption of the fliZ and fliT genes on the chromosome decreased and increased, respectively, class 2 expression . These results suggest that the fliZ and fliT genes may encode positive and negative regulatory factors, respectively, for class 2 expression . Enhancement of class 2 expression by the flgM mutation was cancelled by the coexisting fliZ mutation, indicating that FliZ is essential for this enhancement.

J Clin Microbiol, 2000 May, 38(5), 1860 - 5
Genetic relatedness of Salmonella isolates from nondomestic birds in Southeastern United States; Hudson CR et al.; Salmonella infections have been implicated in large-scale die-offs of wild birds in the United States . Although we know quite a bit about the epidemiology of Salmonella infection among domestic fowl, we know little about the incidence, epidemiology, and genetic relatedness of salmonellae in nondomestic birds . To gain further insight into salmonellae in these hosts, 22 Salmonella isolates from diseased nondomestic birds were screened for the presence of virulence and antibiotic resistance-associated genes and compared genetically using pulsed-field gel electrophoresis (PFGE) and random amplified polymorphic DNA analysis . Of the 22 Salmonella isolates examined, 15 were positive for the invasion gene invA and the virulence plasmid-associated genes spvC and pef . Most (15 of 22) were generally sensitive to antibiotics . However, two Salmonella isolates from pet birds were identified as Salmonella enterica serovar Typhimurium DT104 . Despite the general susceptibility of these Salmonella isolates to most antimicrobial agents, antibiotic resistance-associated genes intI1, merA, and aadA1 were identified in a number of these isolates . Five distinct XbaI and nine distinct BlnI DNA patterns were observed for the 22 Salmonella isolates typed by PFGE . PFGE analysis determined that Salmonella isolates from passerines in Georgia and Wyoming were genetically related.

Appl Environ Microbiol, 2000 May, 66(5), 2001 - 5
Lactic acid permeabilizes gram-negative bacteria by disrupting the outer membrane; Alakomi HL et al.; The effect of lactic acid on the outer membrane permeability of Escherichia coli O157:H7, Pseudomonas aeruginosa, and Salmonella enterica serovar Typhimurium was studied utilizing a fluorescent-probe uptake assay and sensitization to bacteriolysis . For control purposes, similar assays were performed with EDTA (a permeabilizer acting by chelation) and with hydrochloric acid, the latter at pH values corresponding to those yielded by lactic acid, and also in the presence of KCN . Already 5 mM (pH 4.0) lactic acid caused prominent permeabilization in each species, the effect in the fluorescence assay being stronger than that of EDTA or HCl . Similar results were obtained in the presence of KCN, except for P . aeruginosa, for which an increase in the effect of HCl was observed in the presence of KCN . The permeabilization by lactic and hydrochloric acid was partly abolished by MgCl(2) . Lactic acid sensitized E . coli and serovar Typhimurium to the lytic action of sodium dodecyl sulfate (SDS) more efficiently than did HCl, whereas both acids sensitized P . aeruginosa to SDS and to Triton X-100 . P . aeruginosa was effectively sensitized to lysozyme by lactic acid and by HCl . Considerable proportions of lipopolysaccharide were liberated from serovar Typhimurium by these acids; analysis of liberated material by electrophoresis and by fatty acid analysis showed that lactic acid was more active than EDTA or HCl in liberating lipopolysaccharide from the outer membrane . Thus, lactic acid, in addition to its antimicrobial property due to the lowering of the pH, also functions as a permeabilizer of the gram-negative bacterial outer membrane and may act as a potentiator of the effects of other antimicrobial substances.

Appl Environ Microbiol, 2000 May, 66(5), 1769 - 76
Immobilization with metal hydroxides as a means to concentrate food-borne bacteria for detection by cultural and molecular methods; Lucore LA et al.; The application of nucleic acid amplification methods to the detection of food-borne pathogens could be facilitated by concentrating the organisms from the food matrix before detection . This study evaluated the utility of metal hydroxide immobilization for the concentration of bacterial cells from dairy foods prior to detection by cultural and molecular methods . Using reconstituted nonfat dry milk (NFDM) as a model, two food-borne pathogens (Listeria monocytogenes and Salmonella enterica serovar Enteritidis) were concentrated from 25-ml samples by the sequential steps of clarification and high-speed centrifugation (designated primary concentration) and immobilization with zirconium hydroxide and low-speed centrifugation (designated secondary concentration) . Sample volume reduction after immobilization with zirconium hydroxide was 50-fold, with total bacterial recoveries ranging from 78 to 96% of input for serovar Enteritidis and 65 to 96% of input for L . monocytogenes . Immobilized bacteria remained viable and could be enumerated by standard cultural procedures . When followed by RNA extraction and subsequent detection by reverse transcription (RT)-PCR, detection limits of 10(1) to 10(2) CFU/25 ml of reconstituted NFDM were achieved for both organisms . The bacterial-immobilization step was relatively nonspecific, resulting in recovery of >50% of the input cells when evaluated on a panel of representative bacterial strains of significance to foods . The method could be adapted to more complex dairy products, such as whole milk and ice cream, for which bacterial recoveries after immobilization ranged from 64 to >100%, with subsequent RT-PCR detection limits of >/=10(2) CFU/ml for whole milk and >/=10(1) CFU for ice cream for both serovar Enteritidis and L . monocytogenes . The bacterial-immobilization method is easy, rapid, and inexpensive and may have applications for the concentration of a wide variety of food-borne bacteria prior to detection by both conventional and alternative methods.

MMWR CDC Surveill Summ, 2000 Mar 17, 49(1), 1 - 62
Surveillance for foodborne-disease outbreaks--United States, 1993-1997; Olsen SJ et al.; PROBLEM/CONDITION: Since 1973, CDC has maintained a collaborative surveillance program for collection and periodic reporting of data on the occurrence and causes of foodborne-disease outbreaks (FBDOs) in the United States . REPORTING PERIOD COVERED: This summary reviews data from January 1993 through December 1997 . DESCRIPTION OF SYSTEM: The Foodborne-Disease Outbreak Surveillance System reviews data concerning FBDOs, defined as the occurrence of two or more cases of a similar illness resulting from the ingestion of a common food . State and local public health departments have primary responsibility for identifying and investigating FBDOs . State, local, and territorial health departments use a standard form to report these outbreaks to CDC . RESULTS: During 1993-1997, a total of 2,751 outbreaks of foodborne disease were reported (489 in 1993, 653 in 1994, 628 in 1995, 477 in 1996, and 504 in 1997) . These outbreaks caused a reported 86,058 persons to become ill . Among outbreaks for which the etiology was determined, bacterial pathogens caused the largest percentage of outbreaks (75%) and the largest percentage of cases (86%) . Salmonella serotype Enteritidis accounted for the largest number of outbreaks, cases, and deaths; most of these outbreaks were attributed to eating eggs . Chemical agents caused 17% of outbreaks and 1% of cases; viruses, 6% of outbreaks and 8% of cases; and parasites, 2% of outbreaks and 5% of cases . INTERPRETATION: The annual number of FBDOs reported to CDC did not change substantially during this period or from previous years . During this reporting period, S . Enteritidis continued to be a major cause of illness and death . In addition, multistate outbreaks caused by contaminated produce and outbreaks caused by Escherichia coli O157:H7 remained prominent . ACTIONS TAKEN: Current methods to detect FBDOs are improving, and several changes to improve the ease and timeliness of reporting FBDO data are occurring (e.g., a revised form to simplify FBDO reporting by state health departments and electronic reporting methods) . State and local health departments continue to investigate and report FBDOs as part of efforts to better understand and define the epidemiology of foodborne disease in the United States . At the regional and national levels, surveillance data provide an indication of the etiologic agents, vehicles of transmission, and contributing factors associated with FBDOs and help direct public health actions to reduce illness and death caused by FBDOs.

Intensive Care Med, 2000, 26 Suppl 1, S98 - 102
Cytokine and cytokine receptor polymorphisms in infectious disease; van Deventer SJ; Host immune responses strongly control the outcome of infectious disease, and the resistance to bacterial infections in humans is in part genetically determined . Responses to Gram-negative bacterial endotoxin are affected by the concentration of plasma lipoproteins and lipid transport proteins that are genetically controlled . Alterations of plasma lipid profiles by genetic manipulation in mice indeed strongly modify resistance to bacterial infections . Recently, the TLR-4 receptor has been identified as the endotoxin receptor, and TLR-4 mutations are the cause of endotoxin resistance in mice . It is probable that such defects also exist in humans, although they must be rare . The capacity of monocytes to produce TNFalpha varies more than tenfold, and several polymorphisms within the TNFalpha gene have been associated with increased TNFalpha production and increased mortality of sepsis . However, these associations most likely result from linkage disequilibrium with other immune response genes on chromosome 6 . Polymorphisms within the IL-1beta and the IL-1RA genes (located on chromosome 2) are associated with altered protein production rates, and certain haplotypes have been linked to inflammatory disease (no studies in bacterial infectious disease have been published) . Mutations in the receptors for IL-12 and IFNgamma, both critical for clearance of intracellular infectious pathogens, occur in consanguineous populations and are associated with severe recurrent infections with Salmonella species and mycobacteria . In conclusion, no human cytokine deficiency syndromes are known, and it remains uncertain whether genetically determined differences in the production rate of pro-inflammatory cytokines alter the outcome of sepsis . In contrast, mutations in the IL-12 and IFNgamma receptor (and possibly the endotoxin receptor) genes are associated with recurrent bacterial infections, whereas TNFR1 mutations cause fever of unknown origin.

Indian J Exp Biol, 1999 Nov, 37(11), 1101 - 4
Induction of Salmonella enterotoxin (stn) gene expression by epithelial cells (IEC-6); Rahman H et al.; Prevalence of Salmonella enterotoxin (stn) gene among Salmonella enterica and S . bongori was investigated by polymerase chain reaction (PCR) and gene probe and its status of phenotypic expression was examined on chinese hamster ovary cells by cultivating the strains with conventional method for enterotoxin production and by cultivating the organisms in contact with intestinal epithelial cells of rats (IEC-6) . All the 19 strains and serovars of S . enterica such as Typhimurium, Enteritidis, Newport, Weltevreden, Indiana, Gallinarum and Kentucky were found to carry stn gene as examined by PCR and gene probe but only a limited number of strains (13 out of 19) expressed phenotypically the enterotoxin when cultured by conventional method . Cultivation of organisms in contact with epithelial cells induced expression of stn gene phenotypically in all the 19 strains . In contrast to S . enterica, strains of S . bongori were found neither genotypically (stn) nor phenotypically (Stn) positive.

Acta Vet Scand Suppl, 1999, 91, 51 - 8
Programmes to control or eradicate Salmonella in animal production in Denmark; Flensburg J; The number of diagnosed cases of salmonella infections in humans has been increasing during the latest 10 years, for the last 5 years mainly because of an increase in infections with Salmonella Enteritidis . As far as Danish produced animal products is concerned, it is assumed that the most important sources of human salmonella infections are, in order of priority: eggs, poultry meat and pork . In Denmark there are at the moment public and voluntary salmonella pre-harvest reduction programmes in the production of pigs, broilers and eggs . The programme in the pig production is a control programme, that means that the aim is to maintain a generally low level of salmonella in pig herds . At the same time the goal of a low level of salmonella contamination of pork is also pursued through general and specific hygiene measures in the slaughterhouses . The programmes in the poultry production are limited to broilers and hens eggs . They are, at least in theory, eradication programmes where the aim is total freedom from salmonella . According to the rules of Council Directive 92/117/EEC, flocks of hens producing eggs for hatching must be free from Salmonella Enteritidis and Typhimurium, whereas according to the Danish national requirements (Veterinary Service Orders to come into effect shortly), these two salmonella serotypes must be eradicated from flocks of hens producing eggs for sale to consumers and all salmonella serotypes must be eradicated from flocks of hens producing eggs for hatching.

N Engl J Med, 2000 Apr 27, 342(17), 1242 - 9
Ceftriaxone-resistant salmonella infection acquired by a child from cattle; Fey PD et al.; BACKGROUND: The emergence of resistance to antimicrobial agents within the salmonellae is a worldwide problem that has been associated with the use of antibiotics in livestock . Resistance to ceftriaxone and the fluoroquinolones, which are used to treat invasive salmonella infections, is rare in the United States . We analyzed the molecular characteristics of a ceftriaxone-resistant strain of Salmonella enterica serotype typhimurium isolated from a 12-year-old boy with fever, abdominal pain, and diarrhea . METHODS: We used pulsed-field gel electrophoresis and analysis of plasmids and beta-lactamases to compare the ceftriaxone-resistant S . enterica serotype typhimurium from the child with four isolates of this strain obtained from cattle during a local outbreak of salmonellosis . RESULTS: The ceftriaxone-resistant isolate from the child was indistinguishable from one of the isolates from cattle, which was also resistant to ceftriaxone . Both ceftriaxone-resistant isolates were resistant to 13 antimicrobial agents; all but one of the resistance determinants were on a conjugative plasmid of 160 kb that encoded the functional group 1 beta-lactamase CMY-2 . Both ceftriaxone-resistant isolates were closely related to the three other salmonella isolates obtained from cattle, all of which were susceptible to ceftriaxone . CONCLUSIONS: This study provides additional evidence that antibiotic-resistant strains of salmonella in the United States evolve primarily in livestock . Resistance to ceftriaxone, the drug of choice for invasive salmonella disease, is a public health concern, especially with respect to children, since fluoroquinolones, which can also be used to treat this disease, are not approved for use in children.

Poult Sci, 2000 Apr, 79(4), 559 - 63
Influence of the level and location of contamination on the multiplication of Salmonella enteritidis at different storage temperatures in experimentally inoculated eggs; Gast RK et al.; Prompt refrigeration to temperatures capable of restricting microbial growth has been recommended as an approach to reducing the likelihood that contaminated eggs will transmit Salmonella enteritidis to humans . By using experimentally contaminated egg components, the present study determined the extent to which small numbers of S . enteritidis could grow to more dangerous levels at different temperatures over a period up to 3 d . This model was intended to simulate the potential opportunities for S . enteritidis multiplication following oviposition and prior to the achievement of internal temperatures able to prevent further microbial growth in eggs . At a relatively warmer incubation temperature (25 C) and with higher inoculum doses (150 cells), rapid and substantial S . enteritidis multiplication often occurred, especially when the bacteria had an opportunity for access to yolk nutrients and when contaminated eggs were incubated for 2 or 3 d before sampling . Extensive multiplication of S . enteritidis was less frequently observed at lower inoculum doses (15 cells), shorter storage times (1 d), and lower temperatures (10 to 17.5 C) and when contaminants were introduced into the albumen.

Genome Res, 2000 Apr, 10(4), 577 - 86
PipMaker--a web server for aligning two genomic DNA sequences; Schwartz S et al.; PipMaker is a World-Wide Web site for comparing two long DNA sequences to identify conserved segments and for producing informative, high-resolution displays of the resulting alignments . One display is a percent identity plot (pip), which shows both the position in one sequence and the degree of similarity for each aligning segment between the two sequences in a compact and easily understandable form . Positions along the horizontal axis can be labeled with features such as exons of genes and repetitive elements, and colors can be used to clarify and enhance the display . The web site also provides a plot of the locations of those segments in both species (similar to a dot plot) . PipMaker is appropriate for comparing genomic sequences from any two related species, although the types of information that can be inferred (e.g., protein-coding regions and cis-regulatory elements) depend on the level of conservation and the time and divergence rate since the separation of the species . Gene regulatory elements are often detectable as similar, noncoding sequences in species that diverged as much as 100-300 million years ago, such as humans and mice, Caenorhabditis elegans and C . briggsae, or Escherichia coli and Salmonella spp . PipMaker supports analysis of unfinished or "working draft" sequences by permitting one of the two sequences to be in unoriented and unordered contigs.

FEMS Microbiol Ecol, 2000 Apr 1, 32(1), 77 - 85
PCR typing of tetracycline resistance determinants (Tet A-E) in Salmonella enterica serotype Hadar and in the microbial community of activated sludges from hospital and urban wastewater treatment facilities in Belgium; Guillaume G et al.; The distribution of tetracycline resistance determinants Tet A-E was studied by PCR in 40 tetracycline-resistant Salmonella enterica serotype Hadar (S . hadar) isolates collected from human patients in 1996 and 1997, as well as in the microbial community originating from activated sludges of hospital and urban wastewater treatment facilities . A fast DNA extraction and purification method from activated sludges was used to provide amplifiable DNA . The method is based on the direct lysis of bacteria improved by bead-beating followed by DNA purification on polyvinylpolypyrrolidone spin columns to remove PCR inhibitors . The purified DNAs from salmonellae and activated sludges were characterized for the presence of tetracycline determinants with specific primer pairs designed on the basis of published sequences . The Tet A determinant was present in all clinical isolates and DNAs extracted from the bacterial community of the selected activated sludges . The Tet C determinant was identified in only one of the 40 clinical isolates and in six of the seven environmental samples . No signal was detected for Tet B, D and E determinants . This study revealed a high and stable prevalence of the Tet A determinant in both salmonellae clinical isolates and the microbial community of activated sludges from hospital and urban wastewater treatment facilities over a 2-year period.

Vet Res, 2000 Mar-Apr, 31(2), 169 - 85
Epidemiological surveillance of infectious diseases in France; Dufour B et al.; Epidemiological surveillance, namely the continuous monitoring of diseases and health determinants in a population, has developed over the past fifteen years, in the sphere of human health as well as in animal health . All epidemiological surveillance networks include the following four stages: data collection, data transmission, data processing and dissemination of information . However, despite this basic similarity, the very many networks existing in France are extremely varied in nature . At the national level, the bodies involved in epidemiological surveillance for infectious animal diseases are the Direction generale de l'alimentation, the Agence francaise de securite sanitaire des aliments and, to a lesser degree, the Institut francais de recherche pour l'exploitation de la mer . In the field, the networks rely on the Direction des services veterinaires, veterinary practitioners, laboratories in each departement, and livestock producers' groups (especially animal health protection groups) . Some twenty French networks currently in operation are presented in this article according to a classification based on published criteria . In the case of human infectious diseases, epidemiological surveillance is carried out almost entirely by the Direction generale de la sante and the Directions departementales d'action sanitaire et sociale, the Institut de veille sanitaire and the various Centres nationaux de reference (CNRs) . Most human infectious diseases are monitored by one or more of the following broad categories of networks: reporting of notifiable diseases, the CNRs, the network of sentinel doctors, the network of hospital laboratories and departments, and medical causes of death . An example where surveillance is covered by several networks is also presented, namely surveillance for salmonellosis and Salmonella . Lastly, methods for evaluating networks are discussed.

Indian J Med Sci, 1999 Jun, 53(6), 259 - 66
Multidrug resistant Salmonella; Gandhi R et al.; A total of 326 salmonella strains was isolated and studied from suspected enteric fever cases in Mumbai (Bombay) during a 2 year period from May 1992 to July 1994 . These were identified using standard biochemical and serological tests . Bacteriophage typing, antibiotic sensitivity and conjugation experiments were also carried out . S . typhi was the most common serotype accounting for 75.46% of the strains . Among S . typhi strains 87% were biotype I and 13% were biotype II . 9.5% strains were of S . paratyphi A, 5.52% of S . typhimurium, 4.60% of S . worthington, 4.30% of S . havana and 0.62% of S . enteritidis . The commonest bacteriophage type of S . typhi was E1, and of S . paratyphi A type 1, whereas 88.88% strains of S . typhimurium were untypable . Most of the strains were multidrug resistant including commonly used antibiotics such as chloramphemicol, ampicillin, and cotrimaxazole . Quinolone derivatives such as Ciprofloxacin were found to be the most effective drugs . In the conjugation experiments there was direct transfer of resistance pattern and enbloc transfer of resistance was observed in most strains . Salmonella typhi is still the most commonly encountered species . There is an alarming increase in multidrug resistance.

Chem Res Toxicol, 2000 Apr, 13(4), 281 - 6
Mutagenic activity of surface soil and quantification of 1,3-, 1,6-, and 1,8-dinitropyrene isomers in soil in Japan; Watanabe T et al.; To clarify the mutagenic potential of nonagricultural surface soil in Japan, 110 soil samples were collected from five geographically different areas between November 1996 and March 1997, and organic extracts of the soil samples were examined by the Ames/Salmonella assay . Most of the soil extracts showed mutagenicity toward both strains TA98 and TA100 in the presence and/or absence of a mammalian metabolic activation system (S9 mix), suggesting that surface soil is largely contaminated with environmental mutagens . Soil samples collected at Hekinan, Kobe, and Osaka were highly mutagenic toward both strains, and their potencies toward TA98 without S9 mix were extremely high, inducing more than 12 000 revertants per gram of soil . On the other hand, soil samples from Muroran showed strong mutagenicity toward TA100 with S9 mix . Furthermore, 1, 3-dinitropyrene (DNP), 1,6-DNP, and 1,8-DNP in soil samples collected at 10 sampling sites in three metropolitan areas were quantified by fluorometric detection of the corresponding diaminopyrene isomers using high-performance liquid chromatography (HPLC) . Three DNP isomers were detected in all soil samples, and the amounts of 1,3-, 1,6-, and 1,8-DNP isomers in the soil samples were 12-3270, 14-5587, and 13-6809 pg/g, respectively . The gross amount of three DNP isomers in surface soil collected at Hekinan was more than 10 ng per gram of soil . The highest contribution ratios of DNP isomers to the mutagenicity of soil extracts were observed for the samples collected at Osaka, and the total of the contribution ratios of three DNP isomers was about 50% . These results suggest that surface soil is largely contaminated with mutagenic compounds and that DNP isomers are one class of major mutagenic and carcinogenic compounds contaminating surface soil.

EMBO J, 2000 Apr 17, 19(8), 1861 - 72
A small protein that mediates the activation of a two-component system by another two-component system; Kox LF et al.; The PmrA-PmrB two-component system of Salmonella enterica controls resistance to the peptide antibiotic polymyxin B and to several antimicrobial proteins from human neutrophils . Transcription of PmrA-activated genes is induced by high iron, but can also be promoted by growth in low magnesium in a process that requires another two-component system, PhoP-PhoQ . Here, we define the genetic basis for the interaction between the PhoP-PhoQ and PmrA-PmrB systems . We have identified pmrD as a PhoP-activated gene that mediates the transcriptional activation of PmrA-regulated genes during growth in low magnesium . When transcription of pmrD is driven from a heterologous promoter, expression of PmrA-activated genes occurs even at repressing magnesium concentrations and becomes independent of the phoP and phoQ genes . The PmrD effect is specific for PmrA-regulated genes and requires functional PmrA and PmrB proteins . A pmrD mutant is sensitive to polymyxin if grown in low magnesium, but resistant if grown in high iron . The PmrD protein controls the activity of the PmrA-PmrB system at a post-transcriptional level.

Southeast Asian J Trop Med Public Health, 1999 Jun, 30(2), 324 - 7
An outbreak of salmonellosis linked to a marine turtle; O'Grady KA et al.; In September 1998, an outbreak of gastroenteritis occurred in a coastal Aboriginal community in the Northern Territory over a seven day period . An investigation was conducted by the Center for Disease Control, Territory Health Services . Thirty-six cases were detected and 17% (n=6) were hospitalized . Salmonella chester was isolated from eight of nine stool specimens . Sixty-two percent of cases interviewed (n=28) reported consumption of a green turtle (Chelonia mydas) within a median of 24 hours prior to onset of illness . Of the remainder, all but two were contacts of other cases . Salmonella chester was isolated from a section of partially cooked turtle meat . There are no previous published reports of salmonellosis associated with consumption of sea turtles despite them being a popular food source in coastal communities in the Pacific.

Indian J Pediatr, 1998 Jul-Aug, 65(4), 561 - 4
Rapid diagnosis of typhoid fever; Kalhan R et al.; A Reverse Passive Haemagglutination Test (RPHA) was designed for the detection of Salmonella typhi antigen and rapid diagnosis of typhoid fever . Two per cent fresh sheep RBC's were coated with 32 micrograms/ml of immunoglobulin . The minimal detectable level of the antigen was 1250 micrograms/ml . Cross reactions were observed with the samples of patients suffering from Salmonella paratyphi A and pseudomonas infections . The RPHA established was used for the detection of S . typhi antigen in culture broths from 100 patients with clinically suspected typhoid fever with culture and/or widal positive, 50 patients with septicemia caused by bacteria other than S . typhi and 50 normal, afebrile healthy controls . It was found that the sensitivity and specificity of this assay was 70% and 92% respectively.

J Hosp Infect, 2000 Apr, 44(4), 261 - 6
Hospital outbreak of Salmonella virchow possibly associated with a food handler; Maguire H et al.; A foodborne outbreak of salmonella infection at a private hospital in London in 1994 was found to be associated with eating turkey sandwiches prepared by a food handler . One patient, nine staff, and a foodhandler's baby were confirmed to have Salmonella enterica serotype virchow, phage type 26 infection . The attack rate was estimated to be 5% among the approximately 200 patients and staff at risk . A food handler reportedly became ill days after, but her baby days before, the first hospital case . Although it appeared to be a single outbreak, antibiogram analysis, supplemented by plasmid profile typing, demonstrated that there were two strains of S . virchow involved, one with resistance to sulphonamides and trimethoprim and a second sensitive to these antimicrobial drugs . Mother and child had different strains . The investigation demonstrated the importance of full phenotypic characterization of putative outbreak strains including antimicrobial susceptibility testing.Outbreaks of foodborne infection in hospitals are preventable and are associated with high attack rates and disruption of services . There is a need for good infection control policies and training of all staff involved in patient care as well as in catering services . Consultants in Communicable Disease (CCDCs) should include private hospitals in their outbreak control plans . Good working relations between Infection Control Doctors (ICDs) in the private health sector and their local CCDCs are important if outbreaks are to be properly investigated .

Nucleic Acids Res, 2000 May 15, 28(10), 2177 - 86
The complete DNA sequence and analysis of R27, a large IncHI plasmid from Salmonella typhi that is temperature sensitive for transfer; Sherburne CK et al.; Salmonella typhi, the causative agent of typhoid fever, annually infects 16 million people and kills 600 000 world wide . Plasmid-encoded multiple drug resistance in S . typhi is always encoded by plasmids of incompatibility group H (IncH) . The complete DNA sequence of the large temperature-sensitive conjugative plasmid R27, the prototype for the IncHI1 family of plasmids, has been compiled and analyzed . This 180 kb plasmid contains 210 open reading frames (ORFs), of which 14 have been previously identified and 56 exhibit similarity to other plasmid and prokaryotic ORFs . A number of insertion elements were found, including the full Tn 10 transposon, which carries tetracycline resistance genes . Two transfer regions, Tra1 and Tra2, are present, which are separated by a minimum of 64 kb . Homologs of the DNA-binding proteins TlpA and H-NS that act as temperature-regulated repressors in other systems have been located in R27 . Sequence analysis of transfer and replication regions supports a mosaic-like structure for R27 . The genes responsible for conjugation and plasmid maintenance have been identified and mechanisms responsible for thermosensitive transfer are discussed.

Southeast Asian J Trop Med Public Health, 1998 Dec, 29(4), 864 - 71
Detection of IgM antibody against region IV flagellin of Salmonella paratyphi A; Korbsrisate S et al.; Salmonella paratyphi A is a pathogenic bacterium that causes paratyphoid fever . The current laboratory diagnostic techniques are unsatisfactory . To improve diagnosis, a plasmid (pSK-8E) encoding phase 1 flagellin gene nucleotide position 452-890 from S . paratyphi A has been constructed . The recombinant protein expressed from the plasmid has been used to develop an indirect ELISA for IgM antibody detection . Sera from patients with hemoculture positive for S . paratyphi A, S . typhi, other gram-positive and gram-negative bacteria, and dengue hemorrhagic fever as well as from healthy control subjects were tested . Sensitivity, specificity, positive and negative predictive values of the test were 56.9%, 98.8%, 90.6% and 92.1%, respectively . Since the sensitivity was low, the explanation for this result was investigated . It was found that the sensitivity of the test could be increased to 83.3% if the sera were obtained 9-12 days after onset of fever . The sera obtained earlier or later gave only 33.3% and 66.6% sensitivity, respectively . This result suggests that the IgM antibody detection assay which we have developed is a valuable tool for diagnosis of S . paratyphi A infection when the serum samples are taken at the appropriate time.

J AOAC Int, 2000 Mar-Apr, 83(2), 299 - 303
Rapid enzyme-linked immunoassay for detection of Salmonella in food and feed products: performance testing program; Bolton FJ et al.; The BIOLINE Salmonella ELISA Test for Salmonella spp., which is a rapid, easy, and convenient assay was evaluated for use in detecting Salmonella in foods and feeds . Each food matrix or feed was artificially contaminated with low levels of Salmonella . Twenty different matrixes were studied and 20 different Salmonella strains from a broad variety of serogroups (B, C, D, E, F, G, H, I, M, O, P, and U) were used . The EUSA Test kit detected levels as low as 1 cfu/25 g sample with at least 4 of the 20 matrixes tested . The test kit is applicable to all sample types tested . The BIOLINE Salmonella ELISA Test kit has been granted AOAC-RI performance tested status.

Mutat Res, 2000 Apr 13, 467(1), 11 - 9
Statistical modeling and analyses of a base-specific Salmonella mutagenicity assay; Piegorsch WW et al.; Statistical features of a base-specific Salmonella mutagenicity assay are considered in detail, following up on a previous report comparing responses of base-specific Salmonella (Ames II) strains with those of traditional tester strains . In addition to using different Salmonella strains, the new procedure also differs in that it is performed as a microwell fluctuation test, as opposed to the standard plate or preincubation test . This report describes the statistical modeling of data obtained from the use of these new strains in the microwell test procedure . We emphasize how to assess any significant interactions between replicate cultures and exposure doses, and how to identify a significant increase in the mutagenic response to a series of concentrations of a test substance.

Antimicrob Agents Chemother, 2000 May, 44(5), 1359 - 61
Occurrence of a Salmonella enterica serovar typhimurium DT104-like antibiotic resistance gene cluster including the floR gene in S . enterica serovar agona; Cloeckaert A et al.; Recently a chromosomal locus possibly specific for Salmonella enterica serovar Typhimurium DT104 has been reported that contains a multiple antibiotic resistance gene cluster . Evidence is provided that Salmonella enterica serovar Agona strains isolated from poultry harbor a similar gene cluster including the newly described floR gene, conferring cross-resistance to chloramphenicol and florfenicol.

Antimicrob Agents Chemother, 2000 May, 44(5), 1223 - 8
Evidence for active efflux as the primary mechanism of resistance to ciprofloxacin in Salmonella enterica serovar typhimurium; Giraud E et al.; The occurrence of active efflux and cell wall modifications were studied in Salmonella enterica serovar Typhimurium mutants that were selected with enrofloxacin and whose phenotypes of resistance to fluoroquinolones could not be explained only by mutations in the genes coding for gyrase or topoisomerase IV . Mutant BN18/21 exhibited a decreased susceptibility to ciprofloxacin (MIC = 0.125 microg/ml) but did not have a mutation in the gyrA gene . Mutants BN18/41 and BN18/71 had the same substitution, Gly81Cys in GyrA, but exhibited different levels of resistance to ciprofloxacin (MICs = 2 and 8 microg/ml, respectively) . None of the mutants had mutations in the parC gene . Evidence for active efflux was provided by a classical fluorimetric method, which revealed a three- to fourfold decrease in ciprofloxacin accumulation in the three mutants compared to that in the parent strain, which was annulled by addition of the efflux pump inhibitor carbonyl cyanide m-chlorophenylhydrazone . In mutant BN18/71, a second fluorimetric method also showed a 50% reduction in the level of accumulation of ethidium bromide, a known efflux pump substrate . Immunoblotting and enzyme-linked immunosorbent assay experiments with an anti-AcrA antibody revealed that the resistance phenotype was strongly correlated with the expression level of the AcrAB efflux pump and suggested that decreased susceptibility to ciprofloxacin due to active efflux probably related to overproduction of this pump could occur before that due to gyrA mutations . Alterations were also found in the outer membrane protein and lipopolysaccharide profiles of the mutants, and these alterations were possibly responsible for the decrease in the permeability of the outer membrane that was observed in the mutants and that could act synergistically with active efflux to decrease the level of ciprofloxacin accumulation.

Infect Immun, 2000 May, 68(5), 2985 - 91
Interaction of Salmonella enterica serotype Typhimurium with dendritic cells is defined by targeting to compartments lacking lysosomal membrane glycoproteins; Garcia-Del Portillo F et al.; Dendritic cells (DCs) play a central role in the generation of acquired immunity to infections by pathogenic microorganisms . Salmonella enterica serotype Typhimurium is known to survive and proliferate intracellularly within macrophages and nonphagocytic cells, but no data exist on how this pathogen interacts with DCs . In this report, we show the capacity of serotype Typhimurium to survive within the established mouse DC line CB1 . In contrast to the case for the macrophage model, the compartments of DCs containing serotype Typhimurium are devoid of lysosomal membrane glycoproteins and the PhoPQ two-component regulatory system is not essential for pathogen intracellular survival.

Infect Immun, 2000 May, 68(5), 2735 - 43
The flagellar sigma factor FliA (sigma(28)) regulates the expression of Salmonella genes associated with the centisome 63 type III secretion system; Eichelberg K et al.; One of the essential features of all pathogenic strains of Salmonella enterica is the ability to enter into nonphagocytic cells . This pathogenic property is mediated by the Salmonella pathogenicity island 1 (SPI-1)-encoded type III secretion system . Expression of components and substrates of this system is subject to complex regulatory mechanisms . These mechanisms include a number of specific and global transcriptional regulatory proteins . In this study we have compared in S . enterica serovars Typhimurium and Typhi the effect of mutations in flagellar genes on the phenotypes associated with the SPI-1 type III protein secretion system . We found that serovar Typhi strains carrying a null mutation in either of the flagellar regulatory genes flhDC or fliA were severely deficient in entry into cultured epithelial cells and macrophage cytotoxicity . This defect could not be reversed by applying a mild centrifugal force, suggesting that the effects of the mutations were not due to the absence of motility . In contrast, the same mutations had no significant effect on the ability of serovar Typhimurium to enter into cultured Henle-407 cells or to induce macrophage cell death . Consistent with these observations, we found that the mutations in the flagellar regulatory proteins significantly reduced the expression of components of the SPI-1-encoded type III system in serovar Typhi but had a marginal effect in serovar Typhimurium . Our results therefore indicate that there is an overlap between regulatory mechanisms that control flagellar and type III secretion gene expression in Salmonella serovar Typhi.

Infect Immun, 2000 May, 68(5), 2503 - 12
Tetanus toxin fragment C expressed in live Salmonella vaccines enhances antibody responses to its fusion partner Schistosoma haematobium glutathione S-transferase; Lee JJ et al.; Tetanus toxoid has been used widely as an adjuvant . The atoxic fragment C from tetanus toxin (TetC) is potently immunogenic when expressed in Salmonella vaccine strains and has been used as a fusion partner for antigens (Ag) . However, there has been no formal comparison of the immunomodulatory impact of TetC on its fusion partners . In this study, we have addressed this important issue . The protective 28-kDa glutathione S-transferase (GST) from Schistosoma haematobium (Sh28GST) was expressed either as a fusion to TetC or as the full-length Sh28GST alone in a nonvirulent aroA-attenuated strain of Salmonella enterica serovar Typhimurium . The Sh28GST proteins were soluble and stably expressed in Salmonella, as evaluated by Western blotting with TetC and/or Sh28GST antisera . Mice were immunized orally with a single dose of the live recombinant Salmonella . The constructs were stable in mice but, dramatically, only the strain expressing the TetC-Sh28GST fusion elicited significant antibody (Ab) responses directed against Sh28GST as determined by enzyme-linked immunosorbent assay . An analysis of the isotype profiles showed that these mice also produced anti-Sh28GST immunoglobulin A and GST-neutralizing assays revealed high levels of neutralizing Abs in sera . These are important correlates of protection in schistosomiasis . In addition, stimulation of spleen cells from immunized mice with Sh28GST Ag showed that both strains, expressing Sh28GST alone or the TetC-Sh28GST fusion, were able to stimulate the secretion of Th1-related cytokines (gamma interferon and interleukin 2) to comparable levels . Thus, TetC has modulated the immune responses generated against its fusion partner, Sh28GST, by markedly enhancing the Ab responses elicited . These results have important implications in the rational development of live vaccines.

Infect Immun, 2000 May, 68(5), 2410 - 7
Lipopolysaccharide-binding protein and phospholipid transfer protein release lipopolysaccharides from gram-negative bacterial membranes; Vesy CJ et al.; Although animals mobilize their innate defenses against gram-negative bacteria when they sense the lipid A moiety of bacterial lipopolysaccharide (LPS), excessive responses to this conserved bacterial molecule can be harmful . Of the known ways for decreasing the stimulatory potency of LPS in blood, the binding and neutralization of LPS by plasma lipoproteins is most prominent . The mechanisms by which host lipoproteins take up the native LPS that is found in bacterial membranes are poorly understood, however, since almost all studies of host-LPS interactions have used purified LPS aggregates . Using native Salmonella enterica serovar Typhimurium outer membrane fragments (blebs) that contained (3)H-labeled lipopolysaccharide (LPS) and (35)S-labeled protein, we found that two human plasma proteins, LPS-binding protein (LBP) and phospholipid transfer protein (PLTP), can extract {(3)H}LPS from bacterial membranes and transfer it to human high-density lipoproteins (HDL) . Soluble CD14 (sCD14) did not release LPS from blebs yet could facilitate LBP-mediated LPS transfer to HDL . LBP, but not PLTP, also promoted the activation of human monocytes by bleb-derived LPS . Whereas depleting or neutralizing LBP significantly reduced LPS transfer from blebs to lipoproteins in normal human serum, neutralizing serum PLTP had no demonstrable effect . Of the known lipid transfer proteins, LBP is thus most able to transfer LPS from bacterial membranes to the lipoproteins in normal human serum.

J Laryngol Otol, 1999 Dec, 113(12), 1122 - 4
Spontaneous resolution of internal jugular vein thrombosis in a Salmonella neck abscess patient; Lin CH et al.; This article describes a rare case of Salmonella neck abscess complicated by internal jugular vein thrombosis in a 51-year-old patient with previously undiagnosed diabetes . The patient was discharged without any complications after a combination of medical and surgical treatment . Also discussed here are the clinical manifestations, imaging findings, and spontaneous resolution of the internal jugular vein thrombosis . Being immunocompromised is a critical predisposing factor for Salmonella neck abscess . Patient recovery is largely determined by proper incision, drainage of pus and adequate intravenous antibiotics according to bacterial sensitivity tests . Detection of an internal jugular vein thrombosis does not signify a poor prognosis . Spontaneous resolution of thrombosis is encountered after treating the infection.

Mutat Res, 2000 Apr, 462(2-3), 209 - 17
Early detection of carcinogenic substances and modifiers in rats; Ito N et al.; Over the past 20 years, we have been developing in vivo medium-term bioassay systems in rats for detecting carcinogenic and modifying effects of test compounds . The systems are based on the two-step hypothesis of carcinogenesis . In a liver model, male F344 rats are initially given a single dose of diethylnitrosamine (DEN, 200 mg/kg, i.p.) and starting 2 weeks later are treated with test compounds for 6 weeks and then killed, all rats being subjected to two-thirds partial hepatectomy at week 3 . Carcinogenic potential is scored by comparing the numbers and areas per cm(2) of induced glutathione S-transferase placental form (GST-P) positive foci in the livers of groups of about 15 rats with those of corresponding control groups given DEN alone . A positive response is defined as a significant increase in the quantitative values of GST-P-positive foci, such a negative response as no change or a decrease . The results obtained have been compared with reported Salmonella/microsome and long-term carcinogenicity test findings for the same compounds . Of the liver carcinogens, 30 out of 31 (97%) mutagenic and 29 out of 33 (88%) non-mutagenic compounds gave positive results . Carcinogens other than hepatocarcinogens gave a lower proportion of positive results (9 out of 42, 21%) . This bioassay also provides information concerning inhibitory potential . The practical utility and benefits of a multi-organ medium-term experimental protocol for early detection of carcinogenic agents and modifiers acting at sites other than the liver are also discussed.

Biometrics, 1996 Jun, 52(2), 381 - 400
Mixed Poisson regression models with covariate dependent rates; Wang P et al.; This paper studies a class of Poisson mixture models that includes covariates in rates . This model contains Poisson regression and independent Poisson mixtures as special cases . Estimation methods based on the EM and quasi-Newton algorithms, properties of these estimates, a model selection procedure, residual analysis, and goodness-of-fit test are discussed . A Monte Carlo study investigates implementation and model choice issues . This methodology is used to analyze seizure frequency and Ames salmonella assay data.

Cell Mol Life Sci, 2000 Feb, 57(2), 323 - 32
The role of M cells in mucosal immunity; Hathaway LJ et al.; Mucosa-associated lymphoid tissue in the respiratory and digestive tracts are covered by a specialized epithelium, the follicle-associated epithelium, which includes M cells, which are specialized for the uptake and transcytosis of macromolecules and microorganisms . Following transcytosis, antigens are released to cells of the immune system in lymphoid aggregates beneath the epithelium where antigen processing and presentation and stimulation of specific B and T lymphocytes are achieved . Circulation of the lymphoid cells enables their homing to their original, and other, mucosal sites where they exert the effector function . Such a response may be dominated by secretory immunoglobulin A release and may include cytotoxic T lymphocyte action . Binding of particles to the apical M cell membrane may be nonspecific or due to specific interaction between molecules such as integrins and lectins . Exploiting the specific binding to M cells is an aim for mucosal vaccination, for example to increase the efficiency of uptake of an oral vaccine by its conjugation to an M-cell-specific molecule . Alternatively, an M-cell-specific live vector, such as attenuated Salmonella bacteria, may be used to deliver epitopes of other organisms . Mucosal vaccination efficiency may also be enhanced by a temporary increase in the number of M cells . Therefore, investigation of the properties and ontogeny of M cells must be pursued to allow the development of better mucosal vaccines for the future.

Biochim Biophys Acta, 2000 Apr 12, 1484(2-3), 183 - 94
Accumulation of unsaturated lipids in monocytes during early phase pyrogen tolerance; Szewczenko-Pawlikowski M et al.; This paper presents data that inspired a new explanation for the mechanism of early phase endotoxin tolerance . Rabbits injected intravenously with LPS from Salmonella abortus developed a two-phase fever (6 h) and monophasic hyperlipidemia of very low density lipoproteins (two consecutive days) . If during these days rabbits were injected with the same dose of LPS at 24-h intervals, the second phase of fever disappeared, i.e . early phase pyrogenic tolerance was obtained . This was correlated with a decrease of lipoprotein hyperlipidemia (measured 1.5 h after LPS injection) and an accumulation of lipids rich in double bonds in monocytes (measured 3.5 h after LPS injection) . Results showed that the degree of unsaturation of acyl chains (AC) in monocytes (AC/DB, DB=double bonds) is negatively correlated (r=-0.72) with fever response (fever index) . The authors maintain that a gradual increase in monocyte membrane fluidity is an adaptation to repeated exposure of monocytes to lipid A and is responsible for the progressive desensitization of monocytes to endotoxin . It is suggested that disorders of this mechanism lead to an accumulation of abnormal quantities of saturated lipids and cholesterol within macrophages, which, as foam cells, are the starting point for atherosclerosis pathology.

Mol Microbiol, 2000 Mar, 35(6), 1518 - 29
Formate protects stationary-phase Escherichia coli and Salmonella cells from killing by a cationic antimicrobial peptide; Barker HC et al.; For a sustained infection, enteric bacterial pathogens must evade, resist or tolerate a variety of antimicrobial host defence peptides and proteins . We report here that specific organic acids protect stationary-phase Escherichia coli and Salmonella cells from killing by a potent antimicrobial peptide derived from the human bactericidal/permeability-increasing protein (BPI) . BPI-derived peptide P2 rapidly halted oxygen consumption by stationary-phase cells preincubated with glucose, pyruvate or malate and caused a 109-fold drop in cell viability within 90 min of addition . In marked contrast, O2 consumption and viability were not significantly affected in stationary-phase cells preincubated with formate or succinate . Experiments with fdhH, fdoG, fdnG, selC and sdhO mutants indicate that protection by formate and succinate requires their oxidation by the Fdh-N formate dehydrogenase and succinate dehydrogenase respectively . Protection was also dependent on the BipA GTPase but did not require the RpoS sigma factor . We conclude that the primary lesion caused by this cationic peptide is not gross permeabilization of the bacterial cytoplasmic membrane but may involve specific disruption of the respiratory chain . Because P2 shares sequence similarity with a range of other antimicrobial peptides, its cytotoxic mechanism has broader significance . Additionally, protective quantities of formate are secreted by E . coli and Salmonella during growth suggesting that such compounds are important determinants of bacterial survival in the host.

Mol Microbiol, 2000 Mar, 35(6), 1375 - 82
A parallel intraphagosomal survival strategy shared by mycobacterium tuberculosis and Salmonella enterica; Buchmeier N et al.; Mycobacterium tuberculosis and Salmonella enterica cause very different diseases and are only distantly related . However, growth within macrophages is crucial for virulence in both of these intracellular pathogens . Here, we demonstrate that in spite of the phylogenetic distance, M . tuberculosis and Salmonella employ a parallel survival strategy for growth within macrophage phagosomes . Previous studies established that the Salmonella mgtC gene is required for growth within macrophages and for virulence in vivo . M . tuberculosis contains an open reading frame exhibiting 38% amino acid identity with the Salmonella MgtC protein . Upon inactivation of mgtC, the resulting M . tuberculosis mutant was attenuated for virulence in cultured human macrophages and impaired for growth in the lungs and spleens of mice . Replication of the mgtC mutant was inhibited in vitro by a combination of low magnesium and mildly acidic pH suggesting that the M . tuberculosis-containing phagosome has these characteristics . The similar phenotypes displayed by the mgtC mutants of M . tuberculosis and Salmonella suggest that the ability to acquire magnesium is essential for virulence in intracellular pathogens that proliferate within macrophage phagosomes.

Eur J Biochem, 2000 Apr, 267(8), 2218 - 26
Rough and smooth forms of fluorescein-labelled bacterial endotoxin exhibit CD14/LBP dependent and independent binding that is influencedby endotoxin concentration; Triantafilou M et al.; Lipopolysaccharide (LPS, or endotoxin), is a major constituent of the outer membrane of Gram-negative bacteria . Bacteria express either smooth LPS, which is composed of O-antigen (O-Ag), complete core oligosaccharides, and the lipid A, or rough LPS which lack O-Ag but possess lipid A and progressively shorter core oligosaccharides . CD14 has been described as the receptor for complexes of LPS with LPS-binding protein (LBP) . Using flow cytometry we have compared the binding of Salmonella minnesota rough LPS (ReLPS) and Escherichia coli smooth LPS labelled with fluorescein isothiocyanate (FITC-LPS) to Chinese hamster ovary (CHO) cells transfected with human CD14 gene (hCD14-CHO), to MonoMac 6 cells and to endothelial cells . Our results showed that both forms of LPS display the same binding characteristics, and that the binding of FITC-LPS to cells was both CD14- and LBP-dependent for LPS concentrations up to 100 ng.mL-1 . At LPS concentrations higher than 100 ng.mL-1 we observed CD14/LBP-independent binding . CD14/LBP-dependent binding was dose dependent, saturable, and enhanced in the presence of human pooled serum (HPS), and the monoclonal anti-CD14 antibody (MY4) or unlabelled LPS could outcompete it.

Int J Syst Evol Microbiol, 2000 Mar, 50 Pt 2, 941 - 4
Proposal of Salmonella paratyphi sp . nov., nom . rev . and request for an opinion to conserve the specific epithet paratyphi in the binary combination Salmonella paratyphi as nomen epitheton conservandum; Ezaki T et al.; We propose Salmonella paratyphi sp . nov., nom . rev., by raising Salmonella choleraesuis subsp . choleraesuis serovar Paratyphi A to species status and request an Opinion to include the specific epithet paratyphi in the binary combination of Salmonella paratyphi in the list of epitheta specifica conservanda.

Eur J Med Res, 2000 Mar 27, 5(3), 93 - 100
Acute endotoxemia protracts leukocyte / endothelium interaction after local ischemia and reperfusion in striated muscle; Galla TJ et al.; Postischemic reperfusion injury and endotoxemia have been shown to promote multiple organ failure in polytraumatized patients . Both pathomechanisms comprise endothelial injury, leukocyte activation, and enhanced leukocyte/endothelium interaction in the microcirculation . Using a dorsal skinfold chamber model for intravital microscopy in striated muscle of awake hamsters, we investigated whether acute endotoxemia enhances postischemic leukocyte/endothelium interaction . - In control animals (n = 8), reperfusion after 2 hours of pressure induced ischemia elicited the rolling and adhesion of fluorescently stained leukocytes to the endothelium of postcapillary venules with a maximum at 0.5 and 2 hours after reperfusion and a decline towards preischemic values after 24 hours . Postischemic leukocyte adhesion was enhanced and protracted in animals where acute endotoxemia was induced through intravenous injection of endotoxin (Salmonella abortus equi, 0.1 microg inverted question markkg superset-1) either 10 minutes prior to ischemia (n = 8) or to reperfusion (n = 8) . - These results suggest that acute endotoxemia has the potential to aggravate the leukocyte-triggered reperfusion damage to striated muscle and presumably to vital organs and thus favours the development of multiple organ failure after primarily successful reperfusion.

FEMS Microbiol Lett, 2000 Apr 15, 185(2), 175 - 9
Inactivation of the flagellin gene of Salmonella enterica serotype enteritidis strongly reduces invasion into differentiated Caco-2 cells; Van Asten FJ et al.; A nonflagellated mutant of Salmonella enterica serotype Enteritidis was constructed by disrupting the flagellin gene (fliC) . Northern blot analysis indicated that the mutation did not affect expression of the downstream fliU gene . Infection experiments with differentiated Caco-2 cells revealed that the mutant was about 50-fold less invasive than the wild-type strain, while bacterial adherence was unaffected . Complementation of the mutant with an intact fliC copy restored flagella formation and efficient bacterial invasion . Our data demonstrate that the fliC gene of S . enterica serotype Enteritidis is essential for the invasion of Caco-2 cells.

Ann Thorac Surg, 2000 Mar, 69(3), 939 - 40
Salmonella infection of a ventricular aneurysm with mural thrombus; Zheng Y et al.; We describe a case of salmonella infection of a left ventricular aneurysm with a mural thrombus and review 12 cases described in the literature . This entity should be looked for in any patient with persistent or relapsing salmonella bacteremia in whom an intracardiac thrombus is demonstrated . Nuclear imaging may help in the diagnosis . A combined medical and surgical approach should be aggressively pursued because patients who do not undergo an aneurysmectomy are unlikely to survive.

Lett Appl Microbiol, 2000 Mar, 30(3), 233 - 7
Activity of hydrolysed lactoferrin against foodborne pathogenic bacteria in growth media: the effect of EDTA; Branen J et al.; Lactoferrin was hydrolysed with pepsin and the antimicrobial activity of the resulting hydrolysate (HLF) was studied in 1% peptone, 0.05% yeast extract, 1% glucose (PYG) medium and tryptic soy broth (TSB) . HLF was effective against Listeria monocytogenes, enterohaemorrhagic Escherichia coli and Salmonella enteritidis in PYG, however, the highest studied concentration (1.6 mg ml-1) did not inhibit growth of any of these organisms in TSB . The addition of EDTA enhanced the activity of HLF in TSB, indicating that the decreased activity of HLF may have been due, in part, to excess cations in the medium.

J Clin Microbiol, 2000 Apr, 38(4), 1623 - 7
Fluorescent amplified-fragment length polymorphism genotyping of Salmonella enterica subsp . enterica serovars and comparison with pulsed-field gel electrophoresis typing; Lindstedt BA et al.; We have performed the fluorescently labeled amplified-fragment length polymorphism (FAFLP) method on 97 strains of the food-borne pathogen Salmonella enterica subsp . enterica comprising seven different serovars using the restriction enzymes EcoRI and MseI . From the total FAFLP fingerprinted strains, 81 were compared with pulsed-field gel electrophoresis (PFGE) typing of the same strains . The FAFLP method showed a discriminatory power equal to that of PFGE . We report a fast, robust, and high-resolution adaptation of the AFLP assay for fingerprinting S . enterica subsp . enterica serovars with capillary electrophoresis that can be scaled to high throughput on automated analysis instruments.

J Clin Microbiol, 2000 Apr, 38(4), 1581 - 6
Characterization of Salmonella enterica serovar typhimurium DT104 isolated from Denmark and comparison with isolates from Europe and the United States; Baggesen DL et al.; A total of 136 isolates of Salmonella enterica serovar Typhimurium DT104 from Denmark (n = 93), Germany (n = 10), Italy (n = 4), Spain (n = 5), and the United Kingdom (n = 9) were characterized by antimicrobial resistance analysis, plasmid profiling, pulsed-field gel electrophoresis (PFGE) with the restriction enzymes XbaI and BlnI, and analysis for the presence of integrons and antibiotic resistance genes . The isolates from Denmark were from nine pig herds, while the isolates from other countries were both of animal and of human origin . All but 10 isolates were resistant to ampicillin, chloramphenicol, spectinomycin, streptomycin, sulfonamides, and tetracycline . Five isolates from the United Kingdom and Spain were sensitive to all antibiotics examined, whereas four isolates from the United Kingdom and the United States were also resistant to one or more of the antibiotics, namely, gentamicin, neomycin, and trimethoprim . All but two strains had the same PFGE profiles when the XbaI restriction enzyme was used, while seven different profiles were observed when the BlnI restriction enzyme was used . Different dominating BlnI types were observed among European isolates compared with the types observed among those from the United States . All the isolates harbored common 95-kb plasmids either alone or in combination with smaller plasmids, and a total of 11 different plasmid profiles were observed . Furthermore, all but one of the multidrug-resistant isolates contained two integrons, ant (3")-Ia and pse-1 . Sensitive isolates contained no integrons, and isolates that were resistant to spectinomycin, streptomycin, and sulfonamides had only one integron containing ant (3")-Ia . When restriction enzyme BlnI was used, the 14 isolates from one of the nine herds in Denmark showed unique profiles, whereas isolates from the remaining herds were homogeneous . Among isolates from seven of nine herds, the same plasmid profile (95 kb) was observed, but isolates from two herds had different profiles . Thus, either PFGE (with BlnI) or plasmid profiling could distinguish isolates from three of nine pig herds in Denmark . The epidemiological markers (antimicrobial susceptibility testing, plasmid profiling, and PFGE) applied demonstrated high in vivo stability in the Danish herds . This may indicate that some different strains of multidrug-resistant S . enterica serovar Typhimurium DT104 have been introduced into Danish food animal herds . The presence of isolates from six different countries with similar profiles by PFGE with XbaI and highly homogeneous profiles by PFGE with BlnI indicate that multidrug-resistant S . enterica serovar Typhimurium DT104 has probably been spread clonally in these countries . However, some minor variation could be observed by using plasmid profiling and profiling by PFGE with BlnI . Thus, a more sensitive technique for subtyping of strains of DT104 and a broader investigation may help in elucidating the epidemiological spread of DT104 in different parts of the world.

J Clin Microbiol, 2000 Apr, 38(4), 1449 - 52
Analysis of plasmid and chromosomal DNA of multidrug-resistant Salmonella enterica serovar typhi from Asia; Mirza S et al.; Molecular analysis of chromosomal DNA from 193 multidrug-resistant (MDR) Salmonella enterica serovar Typhi isolates from 1990 to 1995 from Pakistan, Kuwait, Malaysia, Bangladesh, and India produced a total of five major different pulsed-field gel electrophoresis (PFGE) patterns . Even within a particular country MDR S . enterica serovar Typhi DNA was found to be in different PFGE groups . Similar self-transferable 98-MDa plasmids belonging to either incompatibility group incHI1 or incHI1/FIIA were implicated in the MDR phenotype in S . enterica serovar Typhi isolates from all the locations except Quetta, Pakistan, where the majority were of incFIA . A total of five different PFGE genotypes with six different plasmids, based on incompatibility and restriction endonuclease analysis groups, were found among these MDR S . enterica serovar Typhi isolates.

Int J Food Microbiol, 2000 Mar 10, 54(1-2), 19 - 25
Quantitative survival of native Salmonella serovars during storage of frozen raw pork; Escartin EF et al.; The quantitative survival of material contaminants of Salmonella serovars was studied in raw pork during frozen storage . Raw pork samples were obtained from public markets in Guadalajara, Mexico, and tested for Salmonella . Three positive samples were selected for survival studies in three different trials . Populations of Salmonella were determined by the most probable number (MPN) method, with isolation on bismuth sulfite agar plates . One typical colony was selected from each plate and subjected to serovar identification . Approximately 20 colonies were serotyped for each portion of frozen pork at each sampling time during storage . During frozen storage, numbers of Salmonella were reduced from 7-11 to 1.6 MPN g(-1) over a period of 22 weeks in Trial 1, from 1500 9000 to 2.5 MPN g(-1) over 42 weeks in Trial 2, and from 2000-20,000 to 20 MPN g(-1) over 78 weeks in Trial 3 . The number of different Salmonella serovars identified was 10, 14 and 29 for Trials 1, 2 and 3, respectively . In Trial 3, S . agona, S . newbrunswick, S . drypool and S . anatum predominated over the other 25 serovars identified . S . agona was not only the most prevalent, but also the most abundant . At 15 weeks of storage, estimated MPNs of this serovar were 700 g(-1) of pork . Most serovars were detected sporadically; nine were isolated only once, and nine only twice . Serovars such as S . derby and S . newlands appeared only at the first sampling time, while others such as S . schwarzengrund, S . dublin and S . newport appeared only at the last sampling time . Most serovars identified in this study are commonly isolated from human clinical sources and from raw or processed foods in Mexico.

Indian Pediatr, 2000 Jan, 37(1), 37 - 43
Neonatal diarrhea in a diarrhea treatment center in Bangladesh: clinical presentation, breastfeeding management and outcome; Haider R et al.; OBJECTIVE: To study the clinical presentation and outcome of neonates admitted with diarrhea, and effect of counseling their mothers for exclusive breastfeeding . DESIGN: Prospective study . SETTING: Inpatient unit . RESULTS: Two hundred and forty-four neonates were studied during 1994-95 . Their mean (SD) age was 18 (6.2) days, and body weight and length were 2.18 (0.52) kg and 47.5 (3.2) cm, respectively . More neonates had some dehydration than severe dehydration (78% vs . 11%), with mean (SD) serum bicarbonate values 9.6 (5.1) mmol/1 . V . cholerae was isolated from 25 (12%), Shigella spp . from 8 (3%), and Salmonella spp . from 3 (1%) of the patients who had rectal swab cultures . Mean (SD) hospital stay was 3.6 (2.1) days, during which the majority (80%) recovered fully, but 29 (13%) left earlier . Eleven (4%) of the neonates had to be referred elsewhere for treatment of other problems and 7 (3%) died . None of the neonates were exclusively breastfed on admission . Excluding mothers of adopted neonates, breastfeeding counseling enabled 64% of the mothers to convert to exclusive breastfeeding during the hospital stay . CONCLUSIONS: Most of the neonates admitted with diarrhea were small and underweight, and had poor feeding practices . The majority of neonates recovered soon, and were exclusively breastfeeding when discharged from the hospital . Breastfeeding counseling should be included as an integral part of case management at all health facilities.

Commun Dis Public Health, 2000 Mar, 3(1), 66 - 7
Infantile Salmonella meningitis associated with gecko-keeping; Cyriac J et al.; A serotype found mainly in reptiles was isolated from cerebrospinal fluid from a 2 month old baby with meningitis . A related salmonella was isolated from gecko faeces from the floor of the tank in the baby's home, suggesting a possible source of infection, and indicating the need for hygienic precautions in homes where reptiles are kept as pets.

Appl Environ Microbiol, 2000 Apr, 66(4), 1544 - 52
Diversity of Salmonella strains isolated from the aquatic environment as determined by serotyping and amplification of the ribosomal DNA spacer regions; Baudart J et al.; Salmonella species are pathogenic bacteria often detected in sewage, freshwater, marine coastal water, and groundwater . Salmonella spp . can survive for long periods in natural waters, and the persistence of specific and epidemic strains is of great concern in public health . However, the diversity of species found in the natural environment remains unknown . The aim of this study was to investigate the diversity of Salmonella strains isolated from different natural aquatic systems within a Mediterranean coastal watershed (river, wastewater, and marine coastal areas) . A total of 574 strains isolated from these natural environments were identified by both conventional serotyping and the ribosomal spacer-heteroduplex polymorphism (RS-HP) method (M . A . Jensen and N . Straus, PCR Methods Appl . 3:186-194, 1993) . More than 40 different serotypes were found, and some serotypes probably mobilized from widespread animal-rearing activities were detected only during storm events . These serotypes may be good indicators of specific contamination sources . Furthermore, the RS-HP method based on the PCR amplification of the intergenic spacer region between the 16S and 23S rRNA genes can produce amplicon profiles allowing the discrimination of species at both serotype and intraserotype levels . This method represents a powerful tool that could be used for rapid typing of Salmonella isolates.

Appl Environ Microbiol, 2000 Apr, 66(4), 1274 - 9
Survival and filamentation of Salmonella enterica serovar enteritidis PT4 and Salmonella enterica serovar typhimurium DT104 at low water activity; Mattick KL et al.; In this study we investigated the long-term survival of and morphological changes in Salmonella strains at low water activity (a(w)) . Salmonella enterica serovar Enteritidis PT4 and Salmonella enterica serovar Typhimurium DT104 survived at low a(w) for long periods, but minimum humectant concentrations of 8% NaCl (a(w), 0 . 95), 96% sucrose (a(w), 0.94), and 32% glycerol (a(w), 0.92) were bactericidal under most conditions . Salmonella rpoS mutants were usually more sensitive to bactericidal levels of NaCl, sucrose, and glycerol . At a lethal a(w), incubation at 37 degrees C resulted in more rapid loss of viability than incubation at 21 degrees C . At a(w) values of 0.93 to 0.98, strains of S . enterica serovar Enteritidis and S . enterica serovar Typhimurium formed filaments, some of which were at least 200 microm long . Filamentation was independent of rpoS expression . When the preparations were returned to high-a(w) conditions, the filaments formed septa, and division was complete within approximately 2 to 3 h . The variable survival of Salmonella strains at low a(w) highlights the importance of strain choice when researchers produce modelling data to simulate worst-case scenarios or conduct risk assessments based on laboratory data . The continued increase in Salmonella biomass at low a(w) (without a concomitant increase in microbial count) would not have been detected by traditional microbiological enumeration tests if the tests had been performed immediately after low-a(w) storage . If Salmonella strains form filaments in food products that have low a(w) values (0.92 to 0.98), there are significant implications for public health and for designing methods for microbiological monitoring.

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