J Food Prot, 2003 Apr, 66(4), 700 - 9 Models of antimicrobial resistance and foodborne illness: examining assumptions and practical applications; Barber DA et al.; Antimicrobial resistance is an issue of increasing global concern . Several investigators have suggested that antibiotic use in food-producing animals is a major contributor to the increasing incidence of antimicrobial-resistant organisms causing illness in humans (F . J . Angulo, K . R . Johnson, R . V . Tauxe, and M . L . Cohen, Microb . Drug Res . 6:77-83, 2000; P . D . Fey, T . J . Safranek, M . E . Rupp, E . F . Dunne, R . Efrain, P . C . Iwen, P . A . Bradford, F . J . Angulo, and S . H . Hinrichs, N . Engl . J . Med . 342:1242-1249, 2000; S . A . McEwen and P . J . Fedorka-Cray, Commun . Infect . Dis . 34(Suppl . 3):S93-S106, 2002; D . L . Smith, A . D . Harris, J . A . Johnson, E . K . Silbergeld, and J . G . Morris, Jr., Proc . Natl . Acad . Sci . USA 99:6434-6439, 2002; D . G . White, S . Zhao, R . Sudler, S . Ayers, S . Friedman, S . Chen, P . F . McDermott, D . D . Wagner, and J . Meng, N . Engl . J . Med . 345:1147-1154, 2001; W . Witte, Science 279:996, 1998) . In this paper, we discuss this and other assumptions relevant to a quantitative risk assessment model for salmonellosis in humans . We also discuss other important aspects of modeling food safety and food-associated antimicrobial resistance risk to humans . We suggest that the role of food-producing animals in the origin and transmission of antimicrobial resistance and "foodborne" pathogens has been overestimated and overemphasized in the scientific literature; consequently, nonfoodborne transmission, including pet-associated human cases, has been underemphasized . Much evidence exists for the potential contribution to infectious disease that may be of human or pet origin (that may contact humans through food but not be of a food origin) . Risk analyses that do not acknowledge the potential for these sources of cross-contamination will understate the contribution that origin has in the realm of foodborne and food-associated diseases (e.g., Salmonella) and the resulting uncertainty levels in the food system, thus leading to biased inferences . We emphasize the importance of evaluating both the foodborne and nonfoodborne transmission risk for salmonellosis and outline the basics of an analytical modeling approach in food safety with examples to illustrate strengths and limitations in the modeling . Examples illustrate, on a simplistic level, how varying assumptions and other inputs can influence the output of food-associated quantitative risk models. J Food Prot, 2003 Apr, 66(4), 656 - 9 Incubation of supplemented egg contents pools to support rapid detection of Salmonella enterica serovar Enteritidis; Gast RK et al.; Detecting internal contamination of eggs with Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) is an important aspect of efforts to identify infected laying flocks . When egg contents pools are tested for Salmonella Enteritidis, a preliminary incubation step is often employed to allow small initial populations of contaminants to multiply to more easily detectable numbers . Consistent detection of Salmonella Enteritidis in egg pools by direct plating requires the presence of at least 10(5) CFU/ml, whereas some very rapid methods can require as many as 10(7) CFU/ml . The present study determined the rates at which initial inocula of approximately 10 Salmonella Enteritidis cells multiplied in 10-egg pools, some of which were supplemented with concentrated nonselective enrichment broth or with a source of iron . At 37 degrees C, Salmonella Enteritidis concentrations in supplemented egg pools usually reached 10(5) CFU/ml within 12 h and 10(7) CFU/ml by 12 to 15 h of incubation . At 25 degrees C, Salmonella Enteritidis concentrations in supplemented egg pools typically attained 10(5) CFU/ml by 18 to 27 h and 10(7) CFU/ml by 27 to 36 h of incubation . At both temperatures, Salmonella Enteritidis multiplication was significantly slower in unsupplemented pools . Accordingly, the length of incubation time necessary for consistent detection of small numbers of Salmonella Enteritidis in egg contents pools depends on the incubation temperature used, on whether the egg pools are supplemented to increase the rate of bacterial multiplication, and on the sensitivity of subsequent tests applied to the incubated pools. J Food Prot, 2003 Apr, 66(4), 549 - 58 Viability of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in yellow fat spreads as affected by storage temperature; Holliday SL et al.; A study was conducted to characterize the survival and inactivation kinetics of a five-serotype mixture of Salmonella (6.23 to 6.55 log10 CFU per 3.5-ml or 4-g sample), a five-strain mixture of Escherichia coli O157:H7 (5.36 to 6.14 log10 CFU per 3.5-ml or 4-g sample), and a six-strain mixture of Listeria monocytogenes (5.91 to 6.18 log10 CFU per 3.5-ml or 4-g sample) inoculated into seven yellow fat spreads (one margarine, one butter-margarine blend, and five dairy and nondairy spreads and toppings) after formulation and processing and stored at 4.4, 10, and 21 degrees C for up to 94 days . Neither Salmonella nor E . coil O157:H7 grew in any of the test products . The time required for the elimination of each pathogen depended on the product and the storage temperature . Death was more rapid at 21 degrees C than at 4.4 or 10 degrees C . Depending on the product, the time required for the elimination of viable cells at 21 degrees C ranged from 5 to 7 days to >94 days for Salmonella, from 3 to 5 days to 28 to 42 days for E . coli O157:H7, and from 10 to 14 days to >94 days for L . monocytogenes . Death was most rapid in a water-continuous spray product (pH 3.66, 4.12% salt) and least rapid in a butter-margarine blend (pH 6.66, 1.88% salt) . E . coli O157:H7 died more rapidly than did Salmonella or L . monocytogenes regardless of storage temperature . Salmonella survived longer in high-fat (> or = 61%) products than in products with lower fat contents . The inhibition of growth is attributed to factors such as acidic pH, salt content, the presence of preservatives, emulsion characteristics, and nutrient deprivation . L . monocytogenes did not grow in six of the test products, but its population increased between 42 and 63 days in a butter-margarine blend stored at 10 degrees C and between 3 and 7 days when the blend was stored at 21 degrees C . On the basis of the experimental parameters examined in this study, traditional margarine and spreads not containing butter are not "potentially hazardous foods" in that they do not support the growth of Salmonella, E . coli O157:H7, or L . monocytogenes. J Food Prot, 2003 Apr, 66(4), 542 - 8 Effectiveness of electrolyzed acidic water in killing Escherichia coli O157:H7, Salmonella enteritidis, and Listeria monocytogenes on the surfaces of tomatoes; Bari ML et al.; A study was conducted to evaluate the efficacy of electrolyzed acidic water, 200-ppm chlorine water, and sterile distilled water in killing Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes on the surfaces of spot-inoculated tomatoes . Inoculated tomatoes were sprayed with electrolyzed acidic water, 200-ppm chlorine water, and sterile distilled water (control) and rubbed by hand for 40 s . Populations of E . coli O157:H7, Salmonella, and L . monocytogenes in the rinse water and in the peptone wash solution were determined . Treatment with 200-ppm chlorine water and electrolyzed acidic water resulted in 4.87- and 7.85-log10 reductions, respectively, in Escherichia coli O157:H7 counts and 4.69- and 7.46-log10 reductions, respectively, in Salmonella counts . Treatment with 200-ppm chlorine water and electrolyzed acidic water reduced the number of L . monocytogenes by 4.76 and 7.54 log10 CFU per tomato, respectively . This study's findings suggest that electrolyzed acidic water could be useful in controlling pathogenic microorganisms on fresh produce. Vet Microbiol, 2003 May 29, 93(3), 223 - 33 Adhesion of Salmonella enterica serotype Enteritidis isolates to chicken isthmal glandular secretions; De Buck J et al.; The ability of Salmonella enterica serotype Enteritidis isolates to adhere to immobilized secretions of the isthmus of the laying hen was determined in an ELISA-type assay . One-third of the 56 isolates tested in the logarithmic growth phase, adhered to the isthmal secretions . Using a binding assay of the isolates to thin paraffin sections of the oviduct, we demonstrated that the receptor of the adhesion was localized inside the tubular gland cells of the isthmus . The adhesion to immobilized isthmal secretions as well as to the paraffin sections was blocked by the addition of mannose . A fimD mutant of S . Enteritidis, lacking type 1 fimbriae, did not adhere, confirming that the adhesion was mediated by type 1 fimbriae . Mannosylated glycoproteins were demonstrated in the isthmus glandular cells using confocal laser scanning microscopy by FITC-labelled Lens culinaris lectins . It is hypothesized that the binding of S . Enteritidis to isthmal secretions could play a role in the contamination of eggs through incorporation of the bacteria in the shell membranes. Mutat Res, 2003 Apr 20, 536(1-2), 91 - 101 Carcinogenic semicarbazide induces sequence-specific DNA damage through the generation of reactive oxygen species and the derived organic radicals; Hirakawa K et al.; Semicarbazide, a hydrazine derivative, is carcinogenic to mice but shows no or little mutagenicity in the Salmonella-microsome test . To clarify whether or not the genotoxic mechanism contributes to the non-mutagenic carcinogenicity of semicarbazide, we investigated DNA damage induced by semicarbazide using 32P-5'-end-labeled DNA fragments obtained from the c-Ha-ras-1 protooncogene and the p53 tumor suppressor gene . Semicarbazide caused DNA damage frequently at the thymine and cytosine residues in the presence of Cu(II) . Catalase and bathocuproine partially inhibited DNA damage, suggesting that hydrogen peroxide plus Cu(I) participates in DNA damage . When a high concentration of semicarbazide was used in the presence of catalase, DNA damage was induced, especially at G in 5'-AG and slightly at 5'-G in GG and GGG sequences . An electron paramagnetic resonance (EPR) spectroscopic study has confirmed that the reaction of semicarbazide with Cu(II) produces carbamoyl radicals (z.rad;CONH(2)), possibly generated via the nitrogen-centered radicals of semicarbazide . Azodicarbonamide also produced carbamoyl radicals and induced DNA damage frequently at 5'-G in GG and GGG sequences, suggesting that carbamoyl radicals participate in this sequence-specific DNA damage by semicarbazide . On the basis of our previous reports, we consider that the sequence-specific DNA damage at G in 5'-AG in the present study is due to the nitrogen-centered radicals . This study has shown that semicarbazide induces DNA damage in the presence of Cu(II) through the formation of hydrogen peroxide and Cu(I) . In addition, semicarbazide-derived free radicals participate in DNA damage . DNA damage induced by these reactive species may be relevant to the carcinogenicity of semicarbazide. J Appl Microbiol, 2003, 94(5), 826 - 35 Cross-contamination with Salmonella on a broiler slaughterhouse line demonstrated by use of epidemiological markers; Olsen JE et al.; AIMS: To investigate contamination of surfaces on a poultry slaughter line from infected poultry and subsequent cross-contamination of non-infected poultry . METHODS AND RESULTS: A broiler slaughterhouse was investigated for the presence of Salmonella on 17 defined points over two 1-week periods . Flocks supplied to slaughter and neck skin samples from processed chicken were likewise investigated . Salmonella was detected in 10 out of 18 flocks at ante-mortem inspection, while seven flocks tested positive in the finished products . Equipment at all but one control point at the slaughter line tested positive at least once during the study . The chicken receiving area was the most contaminated . By comparison of typing results from serotyping, plasmid profile typing and phage typing, direct evidence for cross-contamination with Salm . serotype Typhimurium, Salm . Serotype 4.12:b:- and Salm . serotype Virchow on the slaughter line was obtained for four of the flocks . The cleaning procedure in place did not remove all Salmonella from the contaminated areas . CONCLUSIONS: Evidence for contamination of equipment on a slaughter line and subsequent cross-contamination to non-infected chicken was provided by typing methods . SIGNIFICANCE AND IMPACT OF THE STUDY: This study has provided detailed information on cross-contamination on a slaughter line by the use of phage typing and plasmid profiling . The study stresses the importance of controlling Salmonella in the primary production, as contamination of the equipment on the slaughter line will act as a vehicle to contaminate finished products . Cleaning procedures on slaughter lines cannot be expected to control this problem with the current equipment. J Assoc Physicians India, 2003 Jan, 51, 9 - 11 Role of modified Widal test in the diagnosis of enteric fever; Pai AP et al.; OBJECTIVES: To evaluate the diagnostic specificity of modified Widal for recent infection in comparison with conventional Widal test . METHOD: Modified widal test was simultaneously done along with conventional Widal test in serum samples obtained from 50 bacteriologically positive cases of Salmonella typhi infection as well as 50 healthy individuals . RESULTS: A four-fold difference in the titres was noticed in the 50 sera of the test group and no charge in the titres of the control group . The early rising O antibodies which are predominantly IgM in nature . These are due to recent infection and are inactivated by 2-mercaptoethanol . On the other hand H is a mixture of IgG and IgM hence IgM portion gets inactivated giving rise to fall in titre . By inactivating IgM antibodies in modified Widal test, the agglutination would be brought about only by specific IgG while in the conventional Widal test agglutination is due to specific IgG and IgM . The difference in the titres indicates specific IgM class of antibodies which is the hallmark of recent infection . CONCLUSION: If conventional Widal test and modified Widal test are simultaneously done, one can be definite about the diagnosis of enteric fever. Jpn J Thorac Cardiovasc Surg, 2003 Feb, 51(2), 59 - 61 Successful treatment of a Salmonella aortic arch aneurysm; Hamamoto H et al.; A 52-year-old man hospitalized for hoarseness and chest pain was found in chest computed tomography to have an impending aortic arch aneurysm rupture . Laboratory studies showed the presence of severe inflammation . Based on a clinical diagnosis of infected aortic arch aneurysm, we conducted total arch replacement . Salmonella was identified in the aneurismal wall and antibiotics were administered long-term . The postoperative course was uneventful . The patient was discharged on postoperative day 48 . He has remained afebrile and asymptomatic in the 10 months since surgery but continues to take 300 mg/d of oral levofloxacin. J Virol, 2003 May, 77(9), 5209 - 17 Attenuated Salmonella enterica serovar Typhi and Shigella flexneri 2a strains mucosally deliver DNA vaccines encoding measles virus hemagglutinin, inducing specific immune responses and protection in cotton rats; Pasetti MF et al.; Measles remains a leading cause of child mortality in developing countries . Residual maternal measles antibodies and immunologic immaturity dampen immunogenicity of the current vaccine in young infants . Because cotton rat respiratory tract is susceptible to measles virus (MV) replication after intranasal (i.n.) challenge, this model can be used to assess the efficacy of MV vaccines . Pursuing a new measles vaccine strategy that might be effective in young infants, we used attenuated Salmonella enterica serovar Typhi CVD 908-htrA and Shigella flexneri 2a CVD 1208 vaccines to deliver mucosally to cotton rats eukaryotic expression plasmid pGA3-mH and Sindbis virus-based DNA replicon pMSIN-H encoding MV hemagglutinin (H) . The initial i.n . dose-response with bacterial vectors alone identified a well-tolerated dosage (1 x 10(9) to 7 x 10(9) CFU) and a volume (20 micro l) that elicited strong antivector immune responses . Animals immunized i.n . on days 0, 28, and 76 with bacterial vectors carrying DNA plasmids encoding MV H or immunized parenterally with these naked DNA vaccine plasmids developed MV plaque reduction neutralizing antibodies and proliferative responses against MV antigens . In a subsequent experiment of identical design, cotton rats were challenged with wild-type MV 1 month after the third dose of vaccine or placebo . MV titers were significantly reduced in lung tissue of animals immunized with MV DNA vaccines delivered either via bacterial live vectors or parenterally . Since attenuated serovar Typhi and S . flexneri can deliver measles DNA vaccines mucosally in cotton rats, inducing measles immune responses (including neutralizing antibodies) and protection, boosting strategies can now be evaluated in animals primed with MV DNA vaccines. Klin Lab Diagn, 2003 Feb, (2), 51 - 2 {Rare serotypes of salmonella circulating in Kazakhstan}; Tabaeva AA et al.; The serotypic picture of rare-type salmonellas, isolated in the South region of Kazakhstan, was studied . The circulation of 31 serotypes of 17 groups was established . The circulation of serotypes 0:13, 0:38, 0:44 serogroups, was found among people (patients and bacterium-carriers) . Serotypes 0:28, 0:42, 0:62, 0:66 serogroups, were isolated only from the environment . The combined circulation (patients, bacterium-carriers, environment) was registered for seroviruses 0:14, 0:35 and serogroups 0:58 . The obtained data suggested that separate rare salmonella types area tied to ecology. J Clin Microbiol, 2003 Apr, 41(4), 1617 - 22 Analysis of molecular epidemiology of Chilean Salmonella enterica serotype enteritidis isolates by pulsed-field gel electrophoresis and bacteriophage typing; Fernandez J et al.; Human Salmonella enterica serotype Enteritidis infections emerged in Chile in 1994 . S . enterica serotype Enteritidis phage type 1 isolates predominated in the north, and phage type 4 isolates predominated in the central and southern regions . A study was planned to characterize this epidemic using the best discriminatory typing technique . Research involved 441 S . enterica serotype Enteritidis isolates, including clinical preepidemic samples (n = 74; 1975 to 1993) and epidemic (n = 199), food (n = 72), poultry (n = 57), and some Latin American (n = 39) isolates . The best method was selected based on a sample of preepidemic isolates, analyzing the discriminatory power (DP) obtained by phage typing and randomly amplified polymorphic DNA and pulsed-field gel electophoresis (PFGE) analysis . The highest DP was associated with BlnI PFGE-bacteriophage typing analysis (0.993) . A total of 38 BlnI patterns (B patterns) were identified before the epidemic period, 19 since 1994, and only 4 in both periods . Two major clusters were identified by phylogenetic analysis, and the predominant B patterns clustered in the same branch . Combined analysis revealed that specific B pattern-phage type combinations (subtypes) disappeared before 1994, that different genotypes associated with S . enterica serotype Enteritidis phage type 4 had been observed since 1988, and that strain diversity increased before the expansion of S . enterica serotype Enteritidis in 1994 . Predominant subtype B3-phage type 4 was associated with the central and southern regions, and subtype B38-phage type 1 was associated with the north (P < 0.0001) . Food and poultry isolates matched the predominant S . enterica serotype Enteritidis subtypes, but isolates identified in neighboring countries (Peru and Bolivia) did not match S . enterica serotype Enteritidis subtypes identified in the north of Chile . The results of this work demonstrate that genetic diversity, replacement, and expansion of specific S . enterica serotype Enteritidis subtypes were associated with epidemic changes. J Clin Microbiol, 2003 Apr, 41(4), 1469 - 79 DNA fingerprinting of Salmonella enterica subsp . enterica serovar typhimurium with emphasis on phage type DT104 based on variable number of tandem repeat loci; Lindstedt BA et al.; Seventy-eight human and environmental strains of Salmonella enterica subsp . enterica serovar Typhimurium, as well as 18 isolates of other Salmonella serovars and 6 isolates of Escherichia coli, were subjected to a novel variable number of tandem repeats (VNTR)-based fingerprinting method that showed high discrimination and reproducibility for typing serovar Typhimurium isolates . The method is based on capillary separation of PCR products from fluorescence-labeled VNTR in the serovar Typhimurium genome . The serovar Typhimurium isolates displayed 54 VNTR patterns, and the VNTR assay correctly identified strains from a well-characterized outbreak . Among 37 serovar Typhimurium phage type DT104 isolates, 28 distinct VNTR patterns were found . This VNTR-based method is fast and suitable for complete automation . Our VNTR-based method was capable of high discrimination within the homogeneous serovar Typhimurium DT104 phage type and can be used to trace outbreaks and to monitor DT104 as well as other phage types . The VNTR assay was compared to XbaI pulsed-field gel electrophoresis, amplified fragment length polymorphism analysis, integron-cassette profiles and gene PCR of intI1, qacEDelta1, sulI1, and floR . The VNTR assay showed greatly improved resolution compared to all other tested methods in this study. Microbiol Immunol, 2003, 47(2), 161 - 5 Screening method for Salmonella enterica serovar Typhi and serovar Paratyphi A with reduced susceptibility to fluoroquinolones by PCR-restriction fragment length polymorphism; Hirose K et al.; Salmonella enterica serovar Typhi and serovar Paratyphi A with reduced susceptibility to fluoroquinolones (MICs of ciprofloxacin, 0.25 to 2 microg/ml) have a mutation at codon either Ser-83 or Asp-87 of gyrA gene . A screening method by PCR-restriction fragment length polymorphism (PCR-RFLP) was designed to screen the mutations at codon Ser-83 and Asp-87 of the gyrA gene of S . enterica serovar Typhi and serovar Paratyphi A clinical isolates . This method successfully screened the gyrA mutations of S . enterica serovar Typhi and serovar Paratyphi A with reduced susceptibility to fluoroquinolones. Russ J Immunol, 2000 Jul, 5(2), 209 - 216 Application of Transmission Electron Microscopy for Analysis of Ultrastructural Organization of Circulating Immune Complexes in Patients with Typhoid Fever and Chronic Carriers of Salmonella typhi; Didenko LV et al.; Transmission electron microscopy was used to study the ultrastructural organization of circulating immune complexes (CIC), isolated from patients with typhoid fever in the different periods of acute infectious process (febrile period, period of an early and late reconvalescence), relapse and from acute and chronic carriers of Salmonella typhi in the period of pathogen excreting . It has been shown that preparations of CIC from healthy donors consisted of amorphous mean electron density material, including a cell-like detritus . At acute and chronic infectious process there were bacterial cells in a structure of the CIC . Depending on the period of disease, bacteria had different ultrastructural organization in the CIC . In the febrile period, in the period of an early reconvalescence and in the period of formation of acute carriage of S . typhi, and also in relapse, bacteria had a typical structure, with reference to gram-negative microorganisms . In the period of formation of acute and chronic carriers of S . typhi, in a period of excretion of S . typhi, bacteria in the CIC had ultrastructural organization, relevant to the forms of bacteria with a defective cell wall . Immunocytochemistry research made with the purpose of visualization the O-antigen of S . typhi in bacteria has demonstrated positive immunolabeling on the O-antigen in the bacterial forms and forms with a defective cell wall, and on amorphous mean electron density material . The analysis of ultrastructural organization of the circulating immune complexes and immunolabeling on the O-antigen of S . typhi have allowed to conclude that S . typhi, both typical bacterial form, and the forms with a defective cell wall were the main structural component of circulating immune complexes in acute and chronic forms of infectious process. Microbiology, 2003 Apr, 149(Pt 4), 925 - 39 Genetic modulation of Shigella flexneri 2a lipopolysaccharide O antigen modal chain length reveals that it has been optimized for virulence; Morona R et al.; The lipopolysaccharide (LPS) molecules of Shigella flexneri 2a have O antigen (Oag) polysaccharides with two modal chain length distributions . The chromosomal wzz(SF) gene results in short (S) type Oag chains {11-17 Oag repeat units (RUs)}, and the pHS-2 plasmid-located wzz(pHS2) gene results in very long (VL) type Oag chains (>90 Oag RUs) . S . flexneri wzz(SF) mutants are unable to form plaques on HeLa cell monolayers and F-actin comet tails, indicating that IcsA/VirG function in actin-based motility (ABM) is defective . An S . flexneri wzz(SF) wzz(pHS2) double mutant had LPS with relatively short, random length Oag chains and, paradoxically, was able to form plaques and F-actin comet tails . The influence of Oag modal chain length distribution on virulence and related properties was investigated using complementation with different wzz genes . Wzz(O139) from Vibrio cholerae O139 and Wzz(ST) from Salmonella enterica serovar Typhimurium were fully functional in Shigella flexneri, resulting in LPS with either very short (VS) type Oag chains (2-7 Oag RUs) or long (L) type Oag chains (19-35 RUs), respectively . In the absence of VL-type Oag chains, the VS-, S- and L-type Oag chains were permissive for plaque and F-actin comet tail formation . However, in the presence of LPS with VL-type Oag chains, the VS- and S-type Oag chains but not the L-type Oag chains were permissive for plaque and F-actin comet tail formation . These data, and the results of a previous investigation, show that IcsA function in ABM requires LPS Oag chains with at least two but less than 18 RUs when VL-type Oag chains are co-expressed on the cell surface . However, in the absence of the VL-type Oag chains, LPS Oag chains with at least two but less than 90 RUs are able to support IcsA function in ABM . Indirect immunofluorescence staining of IcsA on the cell surface of the S . flexneri strains did not correlate with the observed effect of Oag chain length on plaque and F-actin comet tail formation . However, when intracellular bacteria lacking VL-type Oag chains were examined, an inverse correlation between Oag modal chain length and detection of IcsA was observed, i.e . staining decreased with increased modal length . It is hypothesized that Oag chains can mask IcsA and interfere with its function in ABM, and a model is presented to explain how LPS Oag and IcsA may interact . It is suggested that S . flexneri 2a has evolved to synthesize LPS with two Oag modal chain lengths, as S-type Oag chains allow IcsA to function in ABM in the presence of VL-type Oag chains that confer resistance to serum. Scand J Infect Dis, 2003, 35(1), 67 - 8 Postoperative mediastinitis due to Salmonella; Fernandez-Ayala M et al.; Mediastinitis remains one of the most serious and dreaded complications of median sternotomy . Salmonella is a rare cause of mediastinal infection . The case is reported of a patient who underwent heart valve surgery and developed a Salmonella enteritidis bacteraemia in the postoperative period, which caused aortic dissection and mediastinitis. Indian J Chest Dis Allied Sci, 2003 Jan-Mar, 45(1), 75 - 7 Pneumonia due to an unusual serotype of Salmonella; Ghadage DP et al.; Salmonella species is a rare cause of infection in the respiratory tract . Pleuropulmonary infection with these organisms are however associated with high mortality . We report a case where serotype Worthington was isolated from a patient of acute pneumonia. Comb Chem High Throughput Screen, 2003 Mar, 6(2), 161 - 6 SAR modeling: effect of experimental ambiguity; Thampatty BP et al.; The applicability of SAR (structure-activity relationship) techniques to data obtained using high throughput screening (HTS) and toxicogenomic techniques is explored . The reason for this study derives from the fact that for economical and time considerations HTS bioassays may consist of single determinations, i.e . lack of duplication . This introduces an element of uncertainty . Using two different data bases of fairly complex biological phenomena (allergic contact dermatitis in humans and the induction of mutations in Salmonella), it is demonstrated that the resulting SAR models can tolerate up to 20% ambiguity in the experimental data. Comb Chem High Throughput Screen, 2003 May, 6(3), 235 - 44 The use of fluorescence polarization assays for the detection of infectious diseases; Jolley ME et al.; Fluorescence Polarization Assays (FPAs) have been shown to have great utility in the detection of infectious diseases . Examples are presented of the use of O-polysaccharides (OPSs) for the detection of antibodies in serum, whole milk and whole blood to gram negative organisms (Brucella spp., Salmonella spp.) . The use of proteins and peptides are also described for the detection of Mycobacterium bovis and Equine Infectious Anemia Virus . Fluorescence Polarization Inhibition Assays (FPIAs) are discussed for the specific and sensitive detection and quantitation of Salmonella spp . cells from culture . An example of the detection of enterohemorrhagic E . coli (EHECS) by Strand Displacement Amplification (SDA), coupled with FP, down to the single cell level, within thirty minutes, is described. East Afr Med J, 2002 Dec, 79(12), 633 - 9 Non-typhi salmonella in children with severe malaria; Oundo JO et al.; OBJECTIVE: To determine the association between Plasmodium falciparum malaria and non-typhi Salmonella in children . DESIGN: Cross-sectional hospital based study . SETTING: Kilifi District Hospital (KDH) between January 1997 and June 2001 . SUBJECTS: Children aged between three months to 123 months (mean age 28.28 months) and who had been admitted to the paediatric or High Dependency Research Ward (HDRW) of the KDH . METHODS: A total of 19, 118 blood cultures routinely obtained for all admissions and 1,820 clinically indicated stools samples were obtained from 9,147 children admitted with malaria . The specimens were cultured and antibiotic sensitivity done using standard laboratory procedures with stringent internal and external quality control in place . RESULTS: The total bacterial pathogens isolated from blood and stool were 1,395/19,118 (7.3%) and 342/1,820 (19%) respectively . Non-typhi salmonella consisted of 260/1,395 (18.6%) of the positive blood cultures and 92/324 (28.4%) of the stool cultures out of which a total of 101 NTS occurred in children with severe malaria . Out of the 9,147 malaria cases admitted, 101/9,147 (1.10%) had concomitant NTS infection . NTS with severe malaria as a proportion of all malaria admissions for the period varied between 0.8% and 1.5% . There was a significant association (p-value=0.032) between clinical outcome of death and female sex of the patient . The NTS isolates which occurred with severe malaria showed various levels of antibiotic resistance . They were resistant to ampicillin (35%), chloramphenicol (18%), gentamicin (22%), cefuroxime (29%), sulphamethoxazole-trimethoprim (39%), ciprofloxacin (3%), cefotaxime (14%), amoxycillin-clavulanic acid (26%) and tobramycin (18.0%) . Multidrug resistance (MDR) was seen in 34 (33.6%) of the isolates . CONCLUSIONS: NTS and severe malaria occurring together are a problem in this area and that a large number of the isolates are MDR . An elaborate case-controlled study is required to elucidate the chain of events of both NTS and malaria parasite co-existence. J Environ Pathol Toxicol Oncol, 2003, 22(1), 69 - 76 Bioassay-guided isolation of antimutagenic factors from fruits of Terminalia bellerica; Kaur S et al.; In the course of our search for novel polyphenolic antimutagenic agents from medicinal plants, we examined water, acetone, and chloroform extracts of Terminalia bellerica for their antimutagenic potency using the Ames Salmonella/microsome assay . Acetone extract exhibited variable inhibitory activity of 65.6%, and 69.7% with 4-O-nitrophenylenediamine (NPD) and sodium azide, respectively (as direct-acting mutagens), and 81.4% with 2-aminofluorene (2AF) (an S9-dependent mutagen), in the preincubation mode of experimentation . Inhibition with chloroform and water extracts was rather insignificant . Studies are well underway to isolate and identify the active polyphenolic compounds from acetone extract, which could be used as effective chemopreventive agents in the future. J Environ Pathol Toxicol Oncol, 2003, 22(1), 59 - 67 Studies on correlation of antimutagenic and antiproliferative activities of Juglans regia L; Kaur K et al.; We investigated the effect of water and acetone extract of Juglans regia L . to evaluate its antimutagenic and antiproliferative activities . The antimutagenic study using TA98 and TA100 tester strains of Salmonella revealed the water and acetone extracts to be more effective than the benzene and chloroform extracts in inhibiting the revertants induced by 2-aminoflourene (2AF) in TA100 tester strains . The most effective extracts in the Ames assay were further evaluated using the Lucifer luciferase assay and in time course studies for antiproliferative activities using the Hoechst staining to observe apoptotic cell deaths . The acetone extract showed a correlation of antimutagenic activities in the Ames assay with its antiproliferative effect in different cell lines, while the water extract exerted its effect distinctly in each cell line . Further studies are still needed to evaluate the cytotoxicity in experiments carried out in vivo. Can Vet J, 2003 Mar, 44(3), 230 - 1 Prevalence of Salmonella in dairy herds in Alberta; Sorensen O et al.; Fifty dairy herds in Alberta were tested for the presence of Salmonella . Four (8%) dairy herds had at least 1 cow shedding Salmonella . Different isolates were identified by serotyping, phage typing, and antibiotic resistance patterns . Pulsed-field gel electrophoresis patterns were determined for unique isolates. Proc Natl Acad Sci U S A, 2003 Apr 15, 100(8), 4706 - 11 Epub 2003 Apr 03. Closing the loop: the PmrA/PmrB two-component system negatively controls expression of its posttranscriptional activator PmrD; Kato A et al.; A fundamental question in biology is how an organism integrates multiple signals to mediate an appropriate cellular response . The PmrAPmrB two-component system of Salmonella enterica can be activated independently by Fe(3+), which is sensed by the PmrB protein, and in low Mg(2+), which is sensed by the PhoQ protein . The low-Mg(2+) activation requires pmrD, a PhoPPhoQ-activated gene that activates the response regulator PmrA at a posttranscriptional level . We now report that pmrD expression is negatively regulated by the PmrAPmrB system . Conditions that activate the PmrA protein independently of pmrD, such as exposure to Fe(3+), resulted in lower levels of pmrD transcription . The PmrA protein footprinted the pmrD promoter upstream of the PhoP-binding site but did not interfere with binding of the PhoP protein . Mutation of the PmrA-binding site in the pmrD promoter abolished PmrA-mediated repression . Negative regulation of the PhoPPhoQ-activated pmrD gene by the PmrAPmrB system closes a regulatory circuit designed to maintain proper cellular levels of activated PmrA protein and constitutes a singular example of a multicomponent feedback loop. Bioresour Technol, 2003 Aug, 89(1), 49 - 56 Transport and survival of bacterial and viral tracers through submerged-flow constructed wetland and sand-filter system; Vega E et al.; Untreated or improperly treated wastewater has often been cited as the primary contamination source of groundwater . The use of decentralized wastewater treatment systems has applicability around the world since it obviates the need for extensive infrastructure development and expenditures . The use of a submerged flow constructed wetland (CW) and a sand filter to remove bacterial and viral pathogens from wastewater streams was evaluated in this study Salmonella sp . and a bacteriophages tracer were used in conjunction with the conservative bromide tracer to understand the fate and transport of these organisms in these treatment systems . Viral breakthrough numbers in the sand filter and CW were similar with a Spearman Rank correlation of 0.8 (P<0.05) . In the CW, the virus exhibited almost a 3-log reduction, while in the sand filter, the viruses exhibited a 2-log reduction . The bacterial tracers, however, did not exhibit similar reductions . Low numbers of bacteria and viruses were still detectable in the effluent streams suggesting that disinfection of the effluent is critical . The survival of the tracer bacteria and viruses was as expected dependent on the biotic and abiotic conditions existing within the wastewater . The results suggest that the microbial removal characteristics of decentralized wastewater treatment systems can vary and depend on factors such as adsorption, desorption and inactivation which in turn depend on the design specifics such as filter media characteristics and local climatic conditions. Thromb Res, 2002 Dec 15, 108(5-6), 329 - 34 Consumption of plasma factor VII in a rabbit model of non-overt disseminated intravascular coagulation; Clarke BJ et al.; INTRODUCTION: We have recently described an experimental animal model of non-overt disseminated intravascular coagulation (DIC) in the rabbit in which the induction of tissue factor (TF) mRNA and TF antigen expression in peripheral blood leukocytes (PBL) was demonstrated to occur within 2 h of administration of low-dose endotoxin {Hematol . J . 2 (2001) 188} . In the present study, we demonstrate that the leukocyte TF expressed has procoagulant activity leading to a rapid decline in the concentration of factor VII (FVII) in rabbit plasma . METHODS: Total plasma FVII antigen and FVIIa were quantitated by rabbit FVII-specific immunoassay and FVIIa-specific clotting assays, respectively . Plasma samples from either saline-injected rabbits or rabbits administered a single bolus of 10 microg/kg Salmonella lipopolysaccharide were compared over a 24-h period . RESULTS: Total plasma FVII antigen decreased progressively post-endotoxin injection, reaching 71% of the baseline concentration at 8 h (p<0.001, n=18), and remained low (78%) at 24 h post-injection (p<0.01, n=16), returning to normal by 48 h . Plasma FVIIa levels increased to 120% within 2 h of endotoxin injection, fell to 73% of the baseline concentration at 8 h (p<0.05, n=18) and returned to normal by 24 h post-endotoxin administration . Procoagulant activity of rabbit peripheral blood leukocytes was enhanced at 2 h (p<0.01, n=6) and 4 h (p<0.05, n=6) post-endotoxin injection . The prothrombin time (PT) was increased by <3 s, and thrombin-antithrombin (TAT) complex formation was not significantly increased in the plasma of endotoxin-treated rabbits . No significant changes in total plasma FVII antigen, FVIIa or leukocyte procoagulant activity were observed in rabbits treated with saline . CONCLUSIONS: We conclude that the activation of FVII to FVIIa and rapid consumption of total FVII/FVIIa occur very early and likely are integral events linked to the initiation and propagation of non-overt DIC induced by endotoxin. J Appl Microbiol, 2003, 94 Suppl, 114S - 119S The rise and fall of Salmonella Enteritidis in the UK; Cogan TA et al.; After rising in the early 1980s, the number of recorded human cases of Salmonella enterica subsp . enterica in the UK has fallen in the last 5 years, with a particular decline in cases of infection with serovar Enteritidis . This decline has been concomitant with the introduction of vaccination of egg-laying hens against serovar Enteritidis . It is likely that other factors such as improved biosecurity in egg-laying flocks, a build-up of immunity in other animals and the rise in the number of livestock infections with host-adapted serovars of Salmonella have also played a part in this decline . Although human Salmonella cases are currently at their lowest level since 1987, it is important to remember that the reasons for the dominance of Enteritidis in human infection are poorly understood and it is possible that other serovars could share similar properties and the eradication of Enteritidis may leave a niche for them to fill. Mol Microbiol, 2003 Apr, 48(2), 573 - 85 Protein-peptidoglycan interactions modulate the assembly of the needle complex in the Salmonella invasion-associated type III secretion system; Pucciarelli MG et al.; The invasion-associated type III secretion system of Salmonella enterica assembles as a supra-molecular structure, termed needle complex, which spans the bacterial envelope . Here, we present evidence for protein-peptidoglycan interactions that modulate the assembly of this organelle . The presence of major membrane components of the needle complex (PrgH, PrgK and InvG) and InvH, required for efficient assembly of the organelle, was examined in peptidoglycan purified by extensive boiling of bacteria in 4% SDS . InvH, PrgH and PrgK, but not InvG, were detected in this purified material . InvH was present in the peptidoglycan in higher relative amounts than PrgH or PrgK, and was the only protein efficiently bound to peptidoglycan in cross-linking experiments . Analysis in mutants defective for needle complex proteins showed that the needle proteins PrgI and PrgJ and, to a lesser extent, InvH, sustain the association of PrgH and PrgK with peptidoglycan . In contrast, the association of InvH with peptidoglycan did not necessitate other needle complex proteins . Functional analysis showed that the association of InvH, PrgH and PrgK with peptidoglycan is abolished in live bacteria carrying structural modifications in the peptidoglycan . The loss of these interactions caused a marked reduction in the number of needle complexes and, concomitantly, in protein secretion and bacterial invasion of cultured eukaryotic cells . Altogether, these data provide the first evidence for an association between proteins of the Salmonella needle complex and the peptidoglycan . In addition, we demonstrate that these protein-peptidoglycan interactions are critical for an efficient and correct assembly of this specialized organelle. Mol Microbiol, 2003 Apr, 48(2), 549 - 59 The role of DNA base excision repair in the pathogenesis of Salmonella enterica serovar Typhimurium; Suvarnapunya AE et al.; The intracellular pathogen, Salmonella enterica serovar Typhimurium, is able to proliferate in phagocytes, although reactive oxygen and nitrogen intermediates are lethal to most phagocytosed bacteria . To determine whether repair of oxidatively damaged DNA is involved in S . typhimurium intramacrophage proliferation, null mutants of the DNA base excision repair (BER) system were generated . These mutants were deficient in discrete enzymes (Deltanth, Deltanei, Deltaxth, Deltanfo) or in the defined glycosylase (Deltanth/nei) and endonuclease (Deltaxth/nfo) steps . In this study, S . typhimurium BER mutants are characterized for the first time . In vitro characterization of the Salmonella BER mutants revealed phenotypes that are mostly consistent with characterized Escherichia coli BER mutants . These strains were used to evaluate the role of BER in the context of Salmonella virulence . S . typhimurium Deltaxth and Deltaxth/nfo were significantly impaired for survival in both cultured and primary macrophages activated with interferon (IFN)-gamma . Survival of Deltaxth and Deltaxth/nfo was improved nearly to wild-type levels in activated primary macrophages lacking both phagocyte oxidase and inducible nitric oxide synthase . In the murine typhoid fever model, Deltanth/nei was fivefold attenuated and Deltaxth/nfo was 12-fold attenuated compared with wild type . These data indicate that DNA oxidation is a mechanism that macrophages use to damage intracellular Salmonella, and suggest that BER-mediated repair of this damage may be important in the establishment of Salmonella infection . We speculate that adaptation to a pathogenic lifestyle may influence the acquisition and retention of redundant BER enzymes. Mol Microbiol, 2003 Apr, 48(2), 385 - 400 virK, somA and rcsC are important for systemic Salmonella enterica serovar Typhimurium infection and cationic peptide resistance; Detweiler CS et al.; Salmonella must express and deploy a type III secretion system located in Salmonella pathogenicity island 2 (SPI-2) in order to survive in host phagocytic vacuoles and to cause systemic infection in mouse models of typhoid fever . A genome-wide approach to screening for Salmonella genes that are transcriptionally co-regulated in vitro with SPI-2 genes was used to identify bacterial loci that might function in a mouse model of systemic disease . Strains with mutations in three SPI-2 co-expressed genes were constructed and tested for their ability to cause disease in mice . We found that virK, a homologue of a Shigella virulence determinant, and rcsC, a sensor kinase, are important at late stages of infection . A second Salmonella gene that has VirK homology, somA, is also important for systemic infection in mice . We have shown that expression of both virK and somA requires the transcription factor PhoP, whereas rcsC does not . Additionally, rcsC expression does not require the transcription factor OmpR, but expression of one of the known targets of RcsC, the yojN rcsB putative operon, does require OmpR . virK, somA and rcsC are expressed in tissue culture macrophages and confer Salmonella resistance to the cationic peptide polymyxin B . We conclude that virK, somA and rcsC are important for late stages of Salmonella enteric fever, and that they probably contribute to the remodelling of the bacterial outer membrane in response to the host environment. J Mol Microbiol Biotechnol, 2003, 5(1), 17 - 28 Acid shock accumulation of sigma S in Salmonella enterica involves increased translation, not regulated degradation; Audia JP et al.; Enteric pathogens such as Salmonella enterica and Escherichia coli face the daunting task of surviving passage through the extremely acid pH of the stomach in order to establish an infection in the host intestinal tract . These organisms have evolved elaborate stress response systems that aid in survival . The alternative sigma factor sigma(S) is a key regulator of many stress responses in S . enterica and is regulated at the levels of transcription, translation, and protein stability . Of these control mechanisms, proteolysis has been considered paramount in determining sigma(S) levels in the cell . Until the current report, acid shock was thought to increase sigma(S) levels by directly regulating degradation . However, mutant strains unable to degrade sigma(S) still exhibited acid shock induction of sigma(S) . We demonstrate here that RPOS translation is a major focus of acid stress control and is responsible for the observed increase in sigma(S) levels . A series of deletions of the 566-nucleotide untranslated region of the RPOS mRNA were constructed to examine the importance of this regulatory region in acid shock induction of RPOS . Progressive deletions starting from the 5' end of the RPOS message produced alternating loss and recovery of acid shock control . The results suggest that competing stem-loop structures work in concert to control the acid shock induction of RPOS . Further, the half-life of sigma(S) was unchanged in response to acid shock and over-expression of the MviA recognition protein resulted in constitutive sigma(S) degradation under acid stress conditions . The data indicate that in log phase, nonstressed cells increasing sigma(S) production is sufficient to increase protein half-life . In toto, these results suggest that acid shock stabilization of sigma(S) is the result of increased synthesis via translational control and does not involve changes in the activity of the MviA (RssB/SprE) ClpXP degradation complex . Therefore, constitutive degradation may enable the cell to reset the level of sigma(S) once acid stress is alleviated . Phytother Res, 2003 Mar, 17(3), 269 - 73 Mutagenic and antimutagenic potential of the medicinal plants M . laevigata and C . xanthocarpa; Fernandes JB et al.; Aqueous extracts of medicinal plants (Mikania laevigata and Campomanesia xanthocarpa) were screened for the presence of mutagenic activity in the Salmonella/microsome assay . The extracts of Campomanesia xanthocarpa showed frameshift (TA97a strain) signs of mutagenic activity without exogenous metabolism (S9 fraction) . The infusions of Mikania laevigata, negative for mutagenic activity, showed high percentages of inhibition of mutagenesis induced by mutagens 2AF (2-amino fluorene), in the presence of exogenous metabolism (S9 fraction), for frameshift (TA98) and base pair substitution (TA100) lesions . In addition, these inhibitions were observed against mutagen SAZ (sodium azide) in assays with the TA100 strain, without exogenous metabolism (S9 fraction) . A synergistic effect was also observed in frameshift mutagenic events, with direct action in the presence of 4NQO (4-oxide-1-nitroquinoline) and a tendency to a low percentage of action enhancement, in the presence of the 2AF mutagen . The variable responses observed in the extract assays show the potentials for interaction of the different active principles in genetic material . Eur J Immunol, 2003 Apr, 33(4), 950 - 61 Combinatorial immunoglobulin light chain variability creates sufficient B cell diversity to mount protective antibody responses against pathogen infections; Senn BM et al.; To analyze how combinatorial light (L) chain diversity influences the B cell repertoire, we studied mice with a homozygous immunoglobulin-heavy-chain null mutation (mu MT), in which the B cell developmental block was overridden by the expression of a transgenic immunoglobulin mu heavy (H) chain derived from a vesicular stomatitis virus Indiana serotype (VSV-IND)-neutralizing Ab (T11 mu MT mice) . The randomly integrated transgene could not undergo secondary rearrangements and was expressed in combination with endogenous kappa or lambda chains . T11 mu MT mice had a skewed B cell repertoire as evidenced by 30-60% VSV-IND-specific peripheral B cells and spontaneous VSV-IND-neutralizing serum titers . Upon immunization, T11 mu MT mice mounted specific IgM antibody responses against VSV-IND but, interestingly, they also responded against VSV New Jersey serotype (VSV-NJ), lymphocytic choriomeningitis virus, poliovirus and Salmonella typhi porins . Variable-region sequence analysis revealed that VSV-NJ-specific antibodies expressed numerous L chains in combination with the transgenic H chain, which was devoid of hypermutations . Thus, in T11 mu MT mice combinatorial L chain variability alone is able to build up a sufficiently complex B cell repertoire to mount protective immunoglobulin responses against a variety of pathogens. Immunogenetics, 2003 Mar, 54(12), 817 - 29 Epub 2003 Feb 21. Genetic variations in the interleukin-12/interleukin-23 receptor (beta1) chain, and implications for IL-12 and IL-23 receptor structure and function; van de Vosse E et al.; Cell-mediated immunity (CMI) plays an essential role in human host defense against intracellular bacteria . Type-1 cytokines, particularly gamma interferon (IFN-gamma), interleukin-12 (IL-12), and IL-23, the major cytokines that regulate IFN-gamma production, are essential in CMI . This is illustrated by patients with unusual severe infections caused by poorly pathogenic mycobacteria and Salmonella species, in whom genetic deficiencies have been identified in several key genes in the type-1 cytokine pathway, including IL12RB1, the gene encoding the beta1 chain of the IL-12 and IL-23 receptors . Several mutations in IL12RB1 with deleterious effects on human IL-12R function have been identified, including nonsense and missense mutations . In addition, a number of coding IL12RB1 polymorphisms have been reported . In order to gain more insight into the effect that IL12RB1 mutations and genetic variations can have on IL-12Rbeta1 function, three approaches have been followed . First, we determined the degree of conservation at the variant amino acid positions in IL-12Rbeta1 between different species, using known deleterious mutations, known variations in IL-12Rbeta1, as well as novel coding variations that we have identified at position S74R and R156H . Second, we analyzed the potential impact of these amino acid variations on the three-dimensional structure of the IL-12Rbeta1 protein . Third, we analyzed the putative functions of different IL-12Rbeta1 domains, partly based on their homology with gp130, and analyzed the possible effects of the above amino acid variations on the function of these domains . Based on these analyses, we propose an integrated model of IL-12Rbeta1 structure and function . This significantly enhances our molecular understanding of the human IL-12 and IL-23 systems. J Bacteriol, 2003 Apr, 185(8), 2485 - 92 Substrate specificity classes and the recognition signal for Salmonella type III flagellar export; Hirano T et al.; Most flagellar proteins of Salmonella are exported to their assembly destination via a specialized apparatus . This apparatus is a member of the type III superfamily, which is widely used for secretion of virulence factors by pathogenic bacteria . Extensive studies have been carried out on the export of several of the flagellar proteins, most notably the hook protein (FlgE), the hook-capping protein (FlgD), and the filament protein flagellin (FliC) . This has led to the concept of two export specificity classes, the rod/hook type and the filament type . However, little direct experimental evidence has been available on the export properties of the basal-body rod proteins (FlgB, FlgC, FlgF, and FlgG), the putative MS ring-rod junction protein (FliE), or the muramidase and putative rod-capping protein (FlgJ) . In this study, we have measured the amounts of these proteins exported before and after hook completion . Their amounts in the culture supernatant from a flgE mutant (which is still at the hook-type specificity stage) were much higher than those from a flgK mutant (which has advanced to the filament-type specificity stage), placing them in the same class as the hook-type proteins . Overproduction of FliE, FlgB, FlgC, FlgF, FlgG, or FlgJ caused inhibition of the motility of wild-type cells and inhibition of the export of the hook-capping protein FlgD . We also examined the question of whether export and translation are linked and found that all substrates tested could be exported after protein synthesis had been blocked by spectinomycin or chloramphenicol . We conclude that the amino acid sequence of these proteins suffices to mediate their recognition and export. J Biol Chem, 2003 Jun 6, 278(23), 20708 - 15 Epub 2003 Mar 31. The YggX protein of Salmonella enterica is involved in Fe(II) trafficking and minimizes the DNA damage caused by hydroxyl radicals: residue CYS-7 is essential for YggX function; Gralnick JA et al.; Previous work from our laboratory identified YggX as a protein whose accumulation increased the resistance of Salmonella enterica to superoxide stress, reversed defects attributed to oxidized {Fe-S} clusters, and decreased the spontaneous mutation frequency of the cells . Here we present work aimed at determining why the accumulation of YggX correlates with reduced mutation frequency . Genetic and biochemical data showed that accumulation of YggX reduced the damage to DNA by hydroxyl radicals . The ability of purified YggX to protect DNA from Fenton chemistry mediated damage in vitro and to decrease the concentration of Fe(II) ions in solution available for chelation provided a framework for the interpretation of data obtained from in vivo experiments . The interpretation of in vitro assay results, within the context of the in vivo phenotypes, was validated by a mutant variant of YggX (C7S) that was unable to function in vivo or in vitro . We propose a model, based on data presented here and reported earlier, that suggests YggX is a player in Fe(II) trafficking in bacteria. FEMS Microbiol Lett, 2003 Mar 28, 220(2), 181 - 6 Exposure of Salmonella Enteritidis to chlorine or food preservatives decreases {corrected} susceptibility to antibiotics; Potenski CJ et al.; Mutants of Salmonella Enteritidis selected following exposure to the sanitizer chlorine or to the preservatives sodium nitrite, sodium benzoate or acetic acid show resistance to multiple antibiotics (tetracycline, chloramphenicol, nalidixic acid, and ciprofloxacin) . Complementation experiments with a functional marR restored antibiotic susceptibility of selected mutants to levels similar to wild-type strains, suggesting that mar mutation was responsible for resistance . The multiple antibiotic resistance (mar) operon is a global regulator controlling intrinsic resistance towards structurally and functionally unrelated antibiotics and other noxious agents . Mutants selected after exposure to an inducing agent maintained elevated antibiotic resistance after serial subculture in media void of the inducing agent . Results highlight the importance of monitoring the use of antimicrobial agents to ensure that concentrations capable of inactivating target pathogens are used. Curr Opin Mol Ther, 2003 Feb, 5(1), 10 - 9 Live attenuated bacteria as vectors to deliver plasmid DNA vaccines; Dietrich G et al.; Live attenuated bacterial vaccines allow vaccination via the mucosal surfaces and specific targeting to professional antigen presenting cells located at the inductive sites of the immune system . A novel approach exploits attenuated intracellular bacteria as a delivery system for eukaryotic antigen expression vectors (so-called DNA vaccines) . Candidate carrier bacteria include attenuated strains of Salmonella, Shigella and Listeria spp, which have been shown, in vitro, to deliver DNA vaccines to human cells . Bacterial DNA vaccine delivery has also demonstrated in vivo efficacy in several experimental animal models of infectious diseases and tumors . The next step should be the clinical assessment of the safety, immunogenicity and efficacy of DNA vaccine delivery by live bacterial vaccines. J Antimicrob Chemother, 2003 May, 51(5), 1287 - 91 Epub 2003 Mar 28. Antimicrobial resistance in clinical isolates of Salmonella enterica serotype Enteritidis: relationships between mutations conferring quinolone resistance, integrons, plasmids and genetic types; Soto SM et al.; In 481 clinical isolates of Salmonella enterica serotype Enteritidis collected from a Spanish region in 2000, 108, 83 and four isolates were resistant, respectively, to nalidixic acid, ampicillin or both . Nalidixic acid resistance was the result of DNA gyrase mutations involving the codons Asp-87 (97 isolates) and Ser-83 (15 isolates) of the gyrA gene; no mutations in parC were detected . In ampicillin-resistant strains, blaTEM genes located on plasmids and/or the chromosome were implicated . Five plasmids containing blaTEM1-like genes were identified, ranging from 7 to 100 kb, four of which were self-transferable; one of these contained a class 1 sul1 integron with an aadA1a gene cassette . This integron was also found on the chromosome of an isolate resistant to ampicillin, streptomycin and sulfadiazine . A relationship between a 40 kb self-transferable plasmid and strains of Salmonella Enteritidis phage type 6a with a distinctive RAPD profile was established. Trends Cell Biol, 2003 Apr, 13(4), 204 - 9 Caspase-1 activation by Salmonella; Jarvelainen HA et al.; Salmonella is an interesting example of how the selective pressure of host environments has led to the evolution of sophisticated bacterial virulence mechanisms . This microbe exploits the first-line of defence, the macrophage, as a crucial tool in the initiation of disease . After invasion of intestinal macrophages, a virulence protein secreted by Salmonella specifically induces apoptotic cell death by activating the cysteine protease caspase-1 . The pro-apoptotic capability is necessary for successful pathogenesis . The study of mechanisms by which Salmonella induces programmed cell death offers new insights into how pathogens cause disease and into general mechanisms of activation of the innate immune system. Clin Microbiol Infect, 2003 Mar, 9(3), 234 - 8 Detection of bloodstream pathogens in a bacille Calmette-Guérin (BCG)-vaccinated pediatric population in Malawi: a pilot study; Archibald LK et al.; Children in Malawi receive bacille Calmette-Guerin (BCG) vaccination within the first 3 days of life . Thus, we hypothesized that Malawian children infected with the human immunodeficiency type 1 virus (HIV-1) might be particularly vulnerable to dissemination of the BCG Mycobacterium bovis strain with which they were vaccinated . Following informed consent by parents, we studied children admitted to a Malawi general hospital during the 1998 wet and dry seasons . Blood from cohorts of acutely ill children was cultured for bacteria, including mycobacteria, and fungi, and tested for anti-HIV-1 antibodies . It was shown that non-typhi Salmonella and Escherichia coli were the predominant bloodstream pathogens during the wet and dry seasons, and that bloodstream dissemination of the BCG M . bovis strain is uncommon in HIV-1-infected children who receive the BCG vaccine. Rocz Panstw Zakl Hig, 2002, 53(4), 351 - 8 {Assessment of microbiological quality of minced meat designed for retail sale}; Bialasiewicz D et al.; In the years 2000-2001 eighty nine portions (445 samples) of minced meat (beef and pork, beef, pork, veal, turkey) produced by supermarkets and other meat producers from Lodz and around Lodz were examined to check if they meet the standard requirements of PN-97/A-82009 and PN-97/A-82009/A1 . The following parameters were determined according to PN-94/A-82055: the total number of microorganisms, most probable number of Escherichia coli, enumeration of Staphylococcus aureus and detection of Salmonella . In addition the presence of Listeria was determined in 25 g of examined meat . The examination showed that 36 (40.4%) portions of minced meat did not meet the requirements of standards mainly because the number of most probable number of E . coli exceeded the norm values. Vet Clin Pathol, 1995, 24(4), 109 - 116 A review of antimicrobial peptides: defensins and related cationic peptides; Evans EW et al.; Cationic antimicrobial peptides are present throughout the plant and animal kingdoms and bear striking structural and functional similarities across species lines . They provide primitive, nonspecific means of combating a variety of bacteria, fungi, enveloped viruses, and protozoa . Some are also cytotoxic against host cells, including neoplastic cells . Cationic antimicrobial peptides may play various roles in inflammation and tissue repair . Antimicrobial peptides are found in epithelial tissues regularly exposed to microbial attack as well as in cells whose primary function is defense against potential pathogens . They constitute an important part of the nonoxidative antimicrobial arsenal of leukocytes . They are preformed and/or readily synthesized when the cells are stimulated by exposure to pathogens . They exert their effects directly by inserting into membranes of target cells and forming ion channels which increase membrane permeability; however, antimicrobial peptides can also act as opsonins to facilitate phagocytosis . Resistance to defensins is a virulence factor for organisms such as Salmonella sp . The study of cationic antimicrobial peptides is increasing our understanding of innate immunity, inflammation, and the pathogenesis of genetic diseases such as specific granule disease in humans . Therapeutic applications of antimicrobial peptides are currently under investigation. J Mol Evol, 2003 Apr, 56(4), 498 - 508 Rates of DNA sequence evolution in experimental populations of Escherichia coli during 20,000 generations; Lenski RE et al.; We examined rates of DNA sequence evolution in 12 populations of Escherichia coli propagated in a glucose minimal medium for 20,000 generations . Previous work saw mutations mediated by mobile elements in these populations, but the extent of other genomic changes was not investigated . Four of the populations evolved defects in DNA repair and became mutators . Some 500 bp was sequenced in each of 36 genes for 50 clones, including 2 ancestral variants, 2 clones from each population at generation 10,000, and 2 from each at generation 20,000 . Ten mutations were found in total, all point mutations including mostly synonymous substitutions and nonsynonymous polymorphisms; all 10 were found in mutator populations . We compared the observed sequence evolution to predictions based on different scenarios . The number of synonymous substitutions is lower than predicted from measured mutation rates in E . coli, but the number is higher than rates based on comparing E . coli and Salmonella genomes . Extrapolating to the entire genome, these data predict about 250 synonymous substitutions on average per mutator population, but only about 3 synonymous substitutions per nonmutator population, during 20,000 generations . These data illustrate the challenge of finding sequence variation among bacterial isolates that share such a recent ancestor . However, this limited variation also provides a useful baseline for research aimed at finding the beneficial substitutions in these populations. Bull Exp Biol Med, 2002 Dec, 134(6), 551 - 3 Perftoran as a means modulating the functional activity of liver macrophages; Kovelenov AY et al.; Experiments on mice showed that perfluorocarbon emulsion Perftoran modulated phagocytic activity of liver macrophages (evaluated by LD50 for Salmonella typhi endotoxin and the rate of elimination of Chinese ink particles from the bloodflow) . Phagocytic activity was suppressed for 3 days after injection of 10 mg/kg emulsion, but then increased above the control . Perftoran had a favorable impact on the course of experimental hepatitis in a model experiment based on hyperactivity of Kupffer cells . Perftoran virtually prevented the development of severe hepatitis after prophylactic injection and notably attenuated hepatocyte cytolysis when used as therapeutic mean. Biochem Biophys Res Commun, 2003 Apr 4, 303(2), 458 - 62 Chemical modification of microcin J25 with diethylpyrocarbonate and carbodiimide: evidence for essential histidyl and carboxyl residues; Bellomio A et al.; In this paper we compared the antibacterial activity of native microcin J25, a peptide antibiotic, with the activities of two analogues obtained by chemical modifications . In the first analogue, the negative charge of glutamic carboxyl group was specifically blocked with an L-glycine methyl ester and in the second the histidine imidazole ring was carbethoxylated . Both analogues decreased notably its antibiotic activity against Escherichia coli and Salmonella newport, strains sensible to the native microcin J25 . The biological activity of the carbethoxylated analogue was completely recovered after treatment with hydroxylamine . The extreme importance of both polar residues could be interpreted as specific structural features indispensable for the peptide transportation into the cell, extrusion outside the cell or alternatively to inhibit the RNA-polymerase. Indian Pediatr, 2003 Mar, 40(3), 252 - 4 Pleural effusion in complicated Salmonella paratyphi A infection; Mathur P et al.; Enteric fever can present with unusual manifestations . We observed a rare case of Salmonella paratyphi A infection in which multiple organs were involved and the organism was isolated from pleural fluid and blood . In the present era of antimicrobial drug resistance, awareness about such atypical presentations is essential to initiate a prompt treatment. Chemosphere, 2003 Jan, 50(3), 275 - 82 Contribution of metabolites to mutagenicity during anaerobic biodegradation of fenitrothion; Matsushita T et al.; The contribution of fenitrothion and its microbial metabolites to the mutagenicity of a fenitrothion-containing solution was investigated during anaerobic biodegradation . Although a mixed culture of bacteria obtained from a paddy field degraded fenitrothion and reduced its concentration from 4.6 to 0.1 mg/l in 6 days, the indirect mutagenicity of the solution in Salmonella strain YG1029 increased . This increase was found to be partially due to amino-fenitrothion generated during the biodegradation . In addition, other unidentified metabolites contributed to the mutagenicity . In contrast, the indirect mutagenicity in strain YG1042, which was initially large because of fenitrothion, then decreased, and increased again . This increase in mutagenicity was also due to amino-fenitrothion and other unidentified metabolites . The mutagenicity in strains YG1029 and YG1042 decreased after day 6 . The greatest contribution of amino-fenitrothion to the mutagenicity was calculated to be 73% and 61% in YG1029 and YG1042 on day 3 of incubation, respectively . That of unidentified metabolites was calculated at 49% and 61% on day 20, respectively . Therefore, because not all the toxic metabolites of a compound can be identified, it is important to evaluate the toxicity of a whole solution in a bioassay such as the Ames assay rather than deducing the toxicity of the solution from the combined toxicities of known metabolites. Proc Natl Acad Sci U S A, 2003 Apr 1, 100(7), 3677 - 82 Epub 2003 Mar 24. Salmochelins, siderophores of Salmonella enterica and uropathogenic Escherichia coli strains, are recognized by the outer membrane receptor IroN; Hantke K et al.; Members of a family of catecholate siderophores, called salmochelins, were isolated by reversed-phase HPLC from Salmonella enterica serotype Typhimurium and structurally characterized by Fourier transform ion cyclotron resonance-MSMS and GC-MS . The tentative structure of salmochelin 1 contained two 2,3- dihydroxybenzoylserine moieties bridged by a glucose residue, bound to the serine hydroxyl group of one moiety and the carboxylate of the second moiety . Salmochelin 2 contained in addition a second glucose residue linked to a third 2,3-dihydroxybenzoylserine moiety . Salmochelins were not produced by an iroBC mutant, which indicated that the IroB protein might be responsible for the glucosyl transfer predicted by sequence similarities to known glycosyltransferases . Uptake experiments with radiolabeled (55)Fe-salmochelin and growth promotion tests with salmochelins showed that the IroN outer membrane receptor, encoded in the iroA locus of S . enterica and uropathogenic Escherichia coli strains, was the main receptor for ferric salmochelin transport. Nucleic Acids Res, 2003 Apr 1, 31(7), 1869 - 76 A non-redundant microarray of genes for two related bacteria; Porwollik S et al.; A microarray with sequences from the annotated open reading frames (ORFs) in Salmonella enterica subspecies 1, serovar Typhimurium was supplemented with annotated chromosomal ORFs from serovar Typhi that are divergent from Typhimurium (>10% DNA sequence divergence) . This non- redundant array was used to (i) measure changes in gene copy number in DNA from actively growing versus stationary Typhi and (ii) to reveal the transcriptional response of Typhi to peroxide, a stress similar to that experienced when they are phagocytosed by macrophages . In S.enterica subspecies 1, pairs of genomes differ in the presence or absence of approximately 10% of their genes . An array twice the size of that needed to cover all ORFs for one genome could carry close homologs of all the ORFs for 10 genomes . Non-redundant DNA arrays could be constructed for any group of closely related organisms that differ by the presence and absence of a few genes. Infect Immun, 2003 Apr, 71(4), 2258 - 61 Vector priming reduces the immunogenicity of Salmonella-based vaccines in Nramp1+/+ mice; Vindurampulle CJ et al.; The present studies in Nramp1(-/-) BALB/c and Nramp1(+/+) CBA mice question the significance of this genotype as a determinant of the level of gut colonization following oral administration of naturally attenuated or highly virulent Salmonella strains . In line with previous results in BALB/c hosts, vector priming of CBA mice with Salmonella enterica serovar Stanley was found to significantly compromise the immunogenicity of a recombinant construct expressing a foreign pilus protein. Infect Immun, 2003 Apr, 71(4), 2247 - 52 Molecular characterization of the prototrophic Salmonella mutants defective for intraepithelial replication; Suvarnapunya AE et al.; Three MudJ prototrophs demonstrated that intracellular replication is a Salmonella virulence trait (K . Y . Leung and B . B . Finlay, Proc . Natl . Acad . Sci . USA, 88:11470-11474, 1991) . mutS and mutH are disrupted in mutants 3-11 and 12-23, and ssaQ is disrupted in mutant 17-21 . Further analysis revealed that loss of Salmonella pathogenicity island 2 function underlies the intracellular replication defect of 3-11 and 17-21. Infect Immun, 2003 Apr, 71(4), 2182 - 91 Rapid protection of gnotobiotic pigs against experimental salmonellosis following induction of polymorphonuclear leukocytes by avirulent Salmonella enterica; Foster N et al.; Oral inoculation of 5-day-old gnotobiotic pigs with Salmonella enterica serovar Typhimurium strain F98 resulted in severe enteritis and invasive disease . Preinoculation 24 h earlier with an avirulent mutant of Salmonella enterica serovar Infantis (1326/28) completely prevented disease for up to 14 days (when the experiment was terminated) . S . enterica serovar Infantis colonized the alimentary tract well, with high bacterial counts in the intestinal lumen but with almost no invasion into the tissues . Unprotected pigs had high S . enterica serovar Typhimurium counts in the intestines, blood, and major nonintestinal organs . Recovery of this strain from the blood and major organs in S . enterica serovar Infantis-protected pigs was substantially reduced despite the fact that intestinal counts were also very high . Protection against disease thus did not involve a colonization exclusion phenomenon . Significant (P < 0.05) infiltration of monocytes/macrophages was observed in the submucosal regions of the intestines of both S . enterica serovar Infantis-protected S . enterica serovar Typhimurium-challenged pigs and unprotected S . enterica serovar Typhimurium-challenged pigs . However, only polymorphonuclear neutrophils (PMNs) were observed throughout the villus, where significant (P < 0.05) numbers infiltrated the lamina propria and the subnuclear and supranuclear regions of the epithelia, indicating that PMN induction and positioning following S . enterica serovar Infantis inoculation was consistent with rapid protection against the challenge strain . Similarly, in vitro experiments using a human fetal intestinal epithelial cell line (INT 407) demonstrated that, although significantly (P < 0.05) fewer S . enterica serovar Infantis than S . enterica serovar Typhimurium organisms invaded the monolayers, S . enterica serovar Infantis induced an NF-kappaB response and significantly (P < 0.05) raised interleukin 8 levels and transmigration of porcine PMN . The results of this study suggest that attenuated Salmonella strains can protect the immature intestine against clinical salmonellosis by PMN induction . They also demonstrate that PMN induction is not necessarily associated with clinical symptoms and/or intestinal pathology. Infect Immun, 2003 Apr, 71(4), 2102 - 9 Salmonella infection induces a hypersecretory phenotype in human intestinal xenografts by inducing cyclooxygenase 2; Bertelsen LS et al.; Enteric Salmonella infection is accompanied by inflammation and diarrhea, and yet little is known about its effects on intestinal epithelial physiology . Since species differences limit the utility of animal tissues and cell lines lack relevant cell-cell interactions, we have used a human model of fetal intestine grown as xenografts in SCID mice . We investigated here the effects of Salmonella enterica serovar Typhimurium SL1344 on xenograft ion transport . Harvested xenografts were stripped of seromuscular layers by blunt dissection, infected with Salmonella, and mounted in Ussing chambers . Salmonella infection for 1 h increased baseline ion transport without altering tissue conductance or morphology . The increased transport was blocked by the cyclooxygenase inhibitor, indomethacin, or the specific Cox-2 inhibitor, NS-398 . Further, xenografts infected for 2 h showed increased secretory responses to the calcium-dependent agonist, carbachol, and the cyclic AMP-dependent agonists prostaglandin E(2) (PGE(2)) and forskolin, which were blocked by indomethacin . Western blot experiments revealed that infection was accompanied by increased cyclooxygenase 2 (Cox-2) expression, with no change in Cox-1 levels . Immunoassay demonstrated basolateral PGE(2) release, which was inhibited by indomethacin . Histological examination of infected xenografts illustrated that upregulated Cox-2 expression was restricted to the epithelium and that little or no invasion of the tissue by Salmonella occurred for up to 2 h . In summary, Salmonella infection rapidly increases Cox-2 expression in human intestinal tissue, accounting for increased epithelial ion transport characteristic of infectious diarrhea. Infect Immun, 2003 Apr, 71(4), 2079 - 86 Major histocompatibility complex heterozygote superiority during coinfection; McClelland EE et al.; Genes of the major histocompatibility complex (MHC) play a critical role in immune recognition, and many alleles confer susceptibility to infectious and autoimmune diseases . How these deleterious alleles persist in populations is controversial . One hypothesis postulates that MHC heterozygote superiority emerges over multiple infections because MHC-mediated resistance is generally dominant and many allele-specific susceptibilities to pathogens will be masked by the resistant allele in heterozygotes . We tested this hypothesis by using experimental coinfections with Salmonella enterica (serovar Typhimurium C5TS) and Theiler's murine encephalomyelitis virus (TMEV) in MHC-congenic mouse strains where one haplotype was resistant to Salmonella and the other was resistant to TMEV . MHC heterozygotes were superior to both homozygotes in 7 out of 8 comparisons (P = 0.0024), and the mean standardized pathogen load of heterozygotes was reduced by 41% over that of homozygotes (P = 0.01) . In contrast, no heterozygote superiority was observed when the MHC haplotype combinations had similar susceptibility profiles to the two pathogens . This is the first experimental evidence for MHC heterozygote superiority against multiple pathogens, a mechanism that would contribute to the evolution of MHC diversity and explain the persistence of alleles conferring susceptibility to disease. Infect Immun, 2003 Apr, 71(4), 1944 - 52 Autodisplay: development of an efficacious system for surface display of antigenic determinants in Salmonella vaccine strains; Kramer U et al.; To optimize antigen delivery by Salmonella vaccine strains, a system for surface display of antigenic determinants was established by using the autotransporter secretion pathway of gram-negative bacteria . A modular system for surface display allowed effective targeting of heterologous antigens or fragments thereof to the bacterial surface by the autotransporter domain of AIDA-I, the Escherichia coli adhesin involved in diffuse adherence . A major histocompatibility complex class II-restricted epitope, comprising amino acids 74 to 86 of the Yersinia enterocolitica heat shock protein Hsp60 (Hsp60(74-86)), was fused to the AIDA-I autotransporter domain, and the resulting fusion protein was expressed at high levels on the cell surface of E . coli and Salmonella enterica serovar Typhimurium . Colonization studies in mice vaccinated with Salmonella strains expressing AIDA-I fusion proteins demonstrated high genetic stability of the generated vaccine strain in vivo . Furthermore, a pronounced T-cell response against Yersinia Hsp60(74-86) was induced in mice vaccinated with a Salmonella vaccine strain expressing the Hsp60(74-86)-AIDA-I fusion protein . This was shown by monitoring Yersinia Hsp60-stimulated IFN-gamma secretion and proliferation of splenic T cells isolated from vaccinated mice . These results demonstrate that the surface display of antigenic determinants by the autotransporter pathway deserves special attention regarding the application in live attenuated Salmonella vaccine strains. Infect Immun, 2003 Apr, 71(4), 1919 - 28 Contribution of the Shigella flexneri Sit, Iuc, and Feo iron acquisition systems to iron acquisition in vitro and in cultured cells; Runyen-Janecky LJ et al.; Shigella flexneri possesses multiple iron acquisition systems, including proteins involved in the synthesis and uptake of siderophores and the Feo system for ferrous iron utilization . We identified an additional S . flexneri putative iron transport gene, sitA, in a screen for S . flexneri genes that are induced in the eukaryotic intracellular environment . sitA was present in all Shigella species and in most enteroinvasive Escherichia coli strains but not in any other E . coli isolates tested . The sit locus consists of four genes encoding a potential ABC transport system . The deduced amino acid sequence of the S . flexneri sit locus was homologous to the Salmonella enterica serovar Typhimurium Sit and Yersinia pestis Yfe systems, which mediate both manganese and iron transport . The S . flexneri sit promoter was repressed by either iron or manganese, and the iron repression was partially dependent upon Fur . A sitA::cam mutation was constructed in S . flexneri . The sitA mutant showed reduced growth, relative to the wild type, in Luria broth containing an iron chelator but formed wild-type plaques on Henle cell monolayers, indicating that the sitA mutant was able to acquire iron and/or manganese in the host cell . However, mutants defective in two of these iron acquisition systems (sitA iucD, sitA feoB, and feoB iucD) formed slightly smaller plaques on Henle cell monolayers . A strain carrying mutations in sitA, feoB, and iucD did not form plaques on Henle cell monolayers. J Antimicrob Chemother, 2003 Apr, 51(4), 1007 - 9 Epub 2003 Feb 25. Florfenicol resistance in Salmonella enterica serovar Newport mediated by a plasmid related to R55 from Klebsiella pneumoniae; Meunier D et al.; Florfenicol resistance has emerged over the past few years in multidrug-resistant Salmonella enterica serovars Typhimurium, Agona and Paratyphi B . The floR gene encoding florfenicol resistance is chromosomally located in these serovars within a genomic island of 43 kb called SGI1 (Salmonella genomic island 1) . In the present study, we characterized florfenicol resistance in a strain of S . enterica serovar Newport isolated from a turkey in 1990 and that lacked SGI1 . Florfenicol resistance was mediated by a conjugative plasmid related to R55 from Klebsiella pneumoniae, which was characterized initially in the 1970s and harbours a gene 95% identical to floR. Antimicrob Agents Chemother, 2003 Apr, 47(4), 1427 - 9 Integron-associated antibiotic resistance in Salmonella enterica serovar typhi from Asia; Ploy MC et al.; Eighteen of 25 isolates of Salmonella enterica serovar Typhi were multidrug resistant and contained class 1 integrons with a single cassette, dfrVII or aadA1 . The dfrVII-containing integron was likely borne on an IncHI1 plasmid . Salmonella serovar Typhi could become resistant to broad-spectrum cephalosporins by integrating cassettes, such as veb-1, a common cassette in Asia. Antimicrob Agents Chemother, 2003 Apr, 47(4), 1297 - 300 Imipenem resistance in a Salmonella clinical strain due to plasmid-mediated class A carbapenemase KPC-2; Miriagou V et al.; A Salmonella enterica serotype Cubana isolate exhibiting resistance to most beta-lactam antibiotics, including oxyimino-cephalosporins and imipenem, was isolated from a 4-year-old boy with gastroenteritis in Maryland . beta-Lactam resistance was mediated by a conjugative plasmid that encoded KPC-2, a class A carbapenemase previously found in a Klebsiella pneumoniae isolate from the Maryland area as well . Sequence analysis of the flanking regions indicated a potential association of bla(KPC-2) with mobile structures. J Microbiol Methods, 2003 May, 53(2), 273 - 85 Specific and selective biosensor for Salmonella and its detection in the environment; Olsen EV et al.; The specific and selective detection of Salmonella typhymurium based on the use of a polyclonal antibody immobilized by the Langmuir-Blodgett method on the surface of a quartz crystal acoustic wave device was demonstrated in liquid samples . These biosensors were selective to S . typhymurium in the presence of large concentrations of Escherichia coli O157:H7 . They were also specific to S . typhymurium since bacteria preincubated with free antibody produced no signal . Dark-field and electron microscopy showed that two different antibodies, polyvalent somatic O and flagellar H7, were immobilized on the sensor surface producing two distinct attachments of bacteria at the liquid-solid interface . The somatic O antibody exhibits a rigid, binding, while the flagellar H7 antibody forms a flexible connection allowing a large degree of freedom . When the attachment of bacteria was rigid and strong, the responses of the acoustic wave sensors correlated with changes in the mass of bacteria present at the liquid-solid interface . In contrast, when attachment was flexible, the sensor signals were inversely proportional to the additional mass of bound bacteria . This difference is probably determined by the interfacial viscoelasticity and by acoustic and electromagnetic coupling . The signals of environmentally aged sensors with either predominantly rigid or flexible positioning of bacteria were correlated with changes in mass at the liquid-solid interface . Sensors with O or H type of binding could be used for analytical purposes. J Microbiol Methods, 2003 May, 53(2), 199 - 209 Detection of pathogenic bacteria in shellfish using multiplex PCR followed by CovaLink NH microwell plate sandwich hybridization; Lee CY et al.; Outbreak of diseases associated with consumption of raw shellfish especially oysters is a major concern to the seafood industry and public health agencies . A multiplex PCR amplification of targeted gene segments followed by DNA-DNA sandwich hybridization was optimized to detect the etiologic agents . First, a multiplex PCR amplification of hns, spvB, vvh, ctx and tl was developed enabling simultaneous detection of total Salmonella enterica serotype Typhimurium, Vibrio vulnificus, Vibrio cholerae and Vibrio parahaemolyticus from both pure cultures and seeded oysters . Amplicons were then subjected to a colorimetric CovaLink NH microwell plate sandwich hybridization using phosphorylated and biotinlylated oligonucleotide probes, the nucleotide sequences of which were located internal to the amplified DNA . The results from the hybridization with the multiplexed PCR amplified DNA exhibited a high signal/noise ratio ranging between 14.1 and 43.2 measured at 405 nm wavelength . The sensitivity of detection for each pathogen was 10(2) cells/g of oyster tissue homogenate . The results from this study showed that the combination of the multiplex PCR with a colorimetric microwell plate sandwich hybridization assay permits a specific, sensitive, and reproducible system for the detection of the microbial pathogens in shellfish, thereby improving the microbiological safety of shellfish to consumers. Bioresour Technol, 2003 Jan, 86(2), 177 - 81 Survival of Salmonella spp . in a simulated acid-phase anaerobic digester treating sewage sludge; Fukushi K et al.; The presence of pathogenic microorganisms in municipal waste sludge may create a serious outbreak of water borne diseases if the sludge is used for agricultural purpose . An attempt to decrease the number of pathogenic microorganisms, Salmonella spp . using a simulated acid-phase anaerobic digester was tested in a laboratory-scale batch experiment . Reduction of Salmonella spp . was demonstrated in a mixture of sludge and organic acid, simulating an acid digester of a two-phase anaerobic digestion process . A high concentration of organic acid at a pH value of 5.5-6.0 prevents a decrease in Salmonella spp . concentration . Almost complete destruction of Salmonella spp . is observed within two days if the pH value is maintained below 5.5. DNA Seq, 2002 Dec, 13(6), 333 - 41 Cloning and characterization of an iron regulated locus, iroA, in Salmonella enterica serovar Choleraesuis; Wu WS et al.; To identify genes belonging to the Ferric update regulator (Fur) regulon of Salmonella enterica serovar Choleraesuis, the Fur titration assay (FURTA) was used to screen a genomic library for Fur promoters and iron-regulated genes . Fifteen FURTA positive clones were identified from this assay . DNA sequence analysis of these clones showed that 11 out of 15 clones had a Fur binding site (Fur box), and 6 of these clones showed homology to the iron-regulated genes of S . enterica serovar Typhi and/or E . coli . One of these clones (pSC4) was homologous to the iroB gene of the iroA locus of S . enterica serovar Typhi . The iroA locus of S . enterica serovar Choleraesuis was cloned from a lambda-dash library and subjected to DNA sequencing . The complete nucleotide sequence of 9848 bp of the iroA locus of S . enterica serovar Choleraesuis consists of iroB, C, D, E and N genes, which are transcriptionally regulated by Fur . The amino acid sequence of IroB, C, D, E and N was 95%, 86, 89, 96 and 96% identity to that of S . enterica serovar Typhi . The IroN gene was homologous to the family of TonB-dependent outer membrane receptors and the putative virulence factor, IroNE . coli, of the extraintestinal pathogenic E . coli . The convalescent porcine sera contained antibodies against the three major iron-regulated outer membrane proteins of S . enterica serovar Choleraesuis . An insertional inactivation of the iroN gene of S . enterica serovar Choleraesuis by allelic exchange resulted in the loss of expression of the 78 kDa protein . However, this mutant had a similar LD50 to mice compared to the parent strain when given intraperitoneally. Clin Infect Dis, 2003 Apr 1, 36(7), 829 - 34 Epub 2003 Mar 18. Risk factors for primary bacteremia and endovascular infection in patients without acquired immunodeficiency syndrome who have nontyphoid salmonellosis; Hsu RB et al.; This study sought to find the risk factors for primary bacteremia, endovascular infection, and in-hospital death for patients without acquired immunodeficiency syndrome who have nontyphoid salmonellosis . From September 1995 through September 2001, 301 patients with nontyphoid salmonellosis were admitted to our hospital; of these patients, 121 had primary bacteremia, and 28 had endovascular infection . Of the 121 patients with primary bacteremia, 64 were aged >50 years, and 26 had endovascular infection . Overall, 90 patients (29.9%) had immunodeficiency . Predictors of primary bacteremia were age; presence of systemic lupus erythematosus; group B, group C, or group D Salmonella infection; and immunodeficiency . The positive predictor of endovascular infection in adult patients with primary bacteremia was group C Salmonella infection, and negative predictors were immunodeficiency and solid-organ cancer . The overall in-hospital mortality rate was 12%; for primary bacteremia, it was 24.8%; for endovascular infection, it was 14.3% . Predictors of in-hospital death were age, extraintestinal infection, and solid-organ malignancy. Mutat Res, 2003 Apr 9, 525(1-2), 77 - 83 Mutation spectra of smoky coal combustion emissions in Salmonella reflect the TP53 and KRAS mutations in lung tumors from smoky coal-exposed individuals; Granville CA et al.; Nonsmoking women in Xuan Wei County, Yunnan Province, China who use smoky coal for cooking and heating in poorly ventilated homes have the highest lung cancer mortality rate in China, and their lung cancer is linked epidemiologically to their use of smoky coal . The emissions contain 81% organic matter, of which 43% is polycyclic aromatic hydrocarbons (PAHs) . Exposure assessment and molecular analysis of the lung tumors from nonsmoking women who use smoky coal strongly indicate that PAHs in the emissions are a primary cause of the elevated lung cancer in this population . Here we have determined the mutation spectra of an extract of smoky coal emissions in Salmonella TA98 and TA100; the extract was not mutagenic in TA104 . The extract was 8.7 x more mutagenic in TA100 with S9 than without (8.7 rev/microg versus 1.0 rev/microg) and was >3 x more mutagenic in TA100 than in TA98--consistent with a prominent role for PAHs in the mutagenicity of the extract because PAHs are generally more mutagenic in the base-substitution strain TA100 than in the frameshift strain TA98 . The extract induced only a hotspot mutation in TA98; another combustion emission, cigarette smoke condensate (CSC), also induces this single class of mutation . In TA100, the mutation spectra of the extract were not significantly different in the presence or absence of S9 and were primarily (78-86%) GC --> TA transversions . This mutation is induced to a similar extent by CSC (78%) and the PAH benzo{a}pyrene (B{a}P) (77%) . The frequency of GC --> TA transversions induced in Salmonella by the extract (78-86%) is similar to the frequency of this mutation in the TP53 (76%) and KRAS (86%) genes of lung tumors from nonsmoking women exposed to smoky coal emissions . The mutation spectra of the extract reflect the presence of PAHs in the mixture and support a role for PAHs in the induction of the mutations and tumors due to exposure to smoky coal emissions. Vet Rec, 2003 Mar 8, 152(10), 283 - 7 Observations on Salmonella contamination of commercial laying farms before and after cleaning and disinfection; Davies R et al.; Little is known about the effectiveness of the cleaning and disinfection methods in use on commercial laying farms in Great Britain . Samples were taken from poultry house structures and equipment of five cage layer flocks, five barn egg production flocks and two free-range flocks . In the free-range houses there was a decrease in Salmonella after cleaning and disinfection, although the soil in the paddocks remained contaminated . In the barn and especially the cage layer houses, significant residual contamination remained on the surfaces of buildings and equipment . Wildlife pests were also found to be carrying Salmonella in the disinfected houses and free-range paddocks. Med Dosw Mikrobiol, 2002, 54(4), 347 - 55 {Evaluation of usefulness for selected virulence markers for identifying pathogenic Yersinia enterocolitica strains . IV . Genes myfA and ureC}; Gierczynski R et al.; We check by polymerase chain reaction (PCR) the presence of gene ureC and myfA, encoding subunits of urease and Myf fimbriae, among clinical and food-originated strains of Yersinia to determine their usefulness as molecular virulence markers of Y . enterocolitica . The examinations were done on 130 clinical strains of Y . enterocolitica O:3/4 isolated in Poland from humans . All strains were obtained from stool and possessed the virulence plasmid pYV . In addition 40 isogenic, plasmid-cured strains were tested . The 52 strains including Y . enterocolitica (biotype 1A, 4, 2 and 1B), Y . pseudotuberculosis, Y . intermedia, Y . frederiksenii, Y . kristensenii, E . coli, Citrobatcer, Shigella and Salmonella were used as controls . The PCR assay resulted in detection of genes: ureC and myfA in genomic DNA of all 130 tested clinical strains of Y . enterocolitica pYV+, as well as in plasmid cured strains . Furthermore, ureC was found in all tested strains of Y . enterocolitica biotype A1 and in one strain of Y . intermedia and Y . kristensenii . In contrast to ureC, myfA was detected only in strains of Y . enterocolitica considered as pathogenic . Obtained results show, gene myfA seems to be the reliable virulence marker of Y . enterocolitica, whereas ureC is not recommended for identification of pathogenic strains of this species. Med Dosw Mikrobiol, 2002, 54(4), 325 - 34 {Phage types and plasmid profiles of plasmid DNA strains of Salmonella enterica subsp . enterica ser . Enteritidis (S . Enteritidis) isolated from food poisoning outbreaks in 2001}; Cieslik A et al.; Salmonella Enteritidis strains are the most often isolated Salmonella serovar in Poland . In the present study, phage typing, antibiotic resistance testing and plasmid profile analysis, have been applied to characterise 41 Polish S . Enteritidis isolates originated from human cases of salmonellosis and from other sources . The typing phages of Ward and colleagues scheme were used to type a total of 41 S . Enteritidis strains coming from Poland . All 41 strains were typable and 5 different phage types were observed . Among 41 strains tested, both PT6 and PT21 were recognized in the 15 strains (36.6%) . Nine strains (22%) belonged to phage type 8 . The others PTs were represented by small amount of strains (PT1var and PT4) . Among all tested isolates only 4 different plasmid profiles were observed . Of the 41 strains investigated, 16 (39%) contained the 57 kb plasmid alone . The remaining 25 strains (61%) except 57 kb plasmid, possessed additional DNA particles . The probable phage type conversion of PT21 to PT1var strain, possibly connected with smaller DNA particle presence, was observed . This hypothesis needs confirmation . The real S . Enteritidis epidemiological situation in Poland should be known after introducing of systematic, annual research program. Indian J Med Sci, 2002 Jun, 56(6), 273 - 5 Enteric fever due to Salmonella Weltevreden in a four-year-old child; Ghadage DP et al.; A four-year old child was admitted with signs and symptoms suggestive of enteric fever . Blood culture and serial stool cultures were undertaken . Weltevreden, a rare Salmonella serotype was isolated from the stool samples . The isolate was sensitive to ampicillin, cefotaxime, gentamicin, chloramphenicol and ciprofloxacin. FEMS Immunol Med Microbiol, 2003 Apr 1, 35(3), 207 - 13 Comparison of the genome sequences of Listeria monocytogenes and Listeria innocua: clues for evolution and pathogenicity; Buchrieser C et al.; Listeria monocytogenes, an invasive opportunistic, food-borne pathogen, remains one of the leading causes of mortality from food-borne infections . The recently determined complete genome sequences of L . monocytogenes strain EGDe and of that of the closely related non-pathogenic species Listeria innocua strain CLIP11262 enhance our knowledge of the genetic basis of the virulence of L . monocytogenes and advance our understanding of the evolution of these Listeria species . Both genomes encode a high number of surface, transport and regulatory proteins . Comparison of the genome organisation revealed a perfect synteny between the two Listeria genomes . Comparison with other closely related bacteria also showed a high conservation in genome organisation among the Listeria, Staphylococcus and Bacillus group of low G+C content bacteria . Distinct G+C content of a number of strain-specific genes suggests intensive lateral gene transfer . The identification of a 55-kb locus encoding proteins with high homology to Salmonella enterica serovar Typhimurium vitamin B(12) synthesis proteins as well as those necessary for degradation of ethanolamine and propanediol further indicates acquisition of a complete metabolic pathway by horizontal gene transfer and a probable role of this locus in anaerobic growth in the host. J Clin Immunol, 2003 Jan, 23(1), 55 - 61 Long-term follow-up and prognosis of chronic granulomatous disease in Yugoslavia: is there a role for early bone marrow transplantation? Pasic S, Minic A, Minic P, Veljkovic D, Lilic D, Slavkovic B, Pejnovic N, Abinun M. We report the long-term follow-up of 12 pediatric-aged patients with chronic granulomatous disease (CGD) . The mean age at the onset of infections was 5 months with a median delay in diagnosis of 2.5 years . Bacille Calmette-Guerin lymphadenitis was the most common presenting infection (6) followed by suppurative lymphadenitis (4), liver abscess (1), or Salmonella sepsis (1) . Prophylaxis with cotrimoxazole was recommended to all patients . During the mean follow-up of 10 years (range, 4-23 years) pneumonitis was the most prevalent infection (91%) followed by lymphadenitis (83%), aphtous stomatitis (58%), and liver abscesses (25%) . Seven (58%) patients developed chronic lung disease due to grossly delayed diagnosis (3) or poor compliance with antimicrobial prophylaxis (4) . Five (41%) patients died during the second decade of life of aspergillosis (3) or chronic lung disease (2) . Probability of survival into the third decade of life was estimated to be only 19% . We argue that HLA-identical bone marrow transplantation (BMT), if possible, should be attempted at early age because of significant morbidity and mortality in adolescence . BMT also should be considered in patients who suffer severe infections despite antimicrobial prophylaxis or patients with evidence of chronic lung disease . Possibility of elective BMT from unrelated donors remains to be carefully evaluated. J Formos Med Assoc, 2002 Sep, 101(9), 665 - 8 Ceftriaxone-resistant Salmonella enterica serovar Hadar: evidence for interspecies transfer of blaCMY-2 in a Taiwanese university hospital; Yan JJ et al.; The emergence of resistance to extended-spectrum cephalosporins in salmonellae is an increasing clinical problem . We report the characteristics of a ceftriaxone-resistant Salmonella enterica serovar Hadar strain collected in 2001 from a patient with a postoperative wound infection in a university hospital in Taiwan . Resistance to extended-spectrum cephalosporins was found to be due to production of the plasmid-mediated CMY-2 AmpC beta-lactamase . To our knowledge, this is the first report of S . hadar harboring blaCMY-2 . Seven CMY-2-producing Escherichia coli isolates collected in 2000 were investigated for comparison . Conjugation experiments and plasmid analysis showed an identical plasmid carrying blaCMY-2 in both the Salmonella isolate and one E . coli isolate, suggesting the possibility that the Salmonella isolate acquired the resistance plasmid from E . coli . These findings suggest that measures are necessary to restrict antibiotic use and so prevent the spread and development of antibiotic resistance in Taiwan. J Formos Med Assoc, 2002 Sep, 101(9), 661 - 4 Identification of Escherichia coli O157:H7 by multiplex PCR with primers specific to the hlyA, eaeA, stx1, stx2, fliC and rfb genes; Pan TM et al.; Escherichia coli O157:H7 can cause fatal diseases such as hemolytic-uremic syndrome and thrombotic thrombocytopenic purpura . The early symptoms of E . coli O157:H7 infection are similar to those of infection with other gastrointestinal bacteria, so the availability of a rapid and precise method to identify E . coli O157:H7 is important for early recognition . We report a multiplex polymerase chain reaction (PCR) with primers to detect the presence of the E . coli O157:H7 genes hlyA, which produces enterohemolysin, eaeA (intimin), stx1 (Shiga-like toxin I), stx2 (Shiga-like toxin II), fliC (flagella H-antigen), and rfb (surface O-antigen) . The technique improves specificity compared to general PCR when used with > or = 10(3) CFU/assay . Specificity was examined using 32 E . coli O157:H7 strains from the USA, Japan, Canada and Taiwan, all of which were positive for hlyA, eaeA, fliC, rfb, and stx1 and/or stx2 . Thirty-five non-O157 enterovirulent E . coli strains, two Shigella sp strains, and two Salmonella sp strains were also examined and none gave the positive gene expression results described above . This multiplex PCR was highly specific in identifying E . coli O157 and was more useful than general PCR in early clinical detection of this pathogen. Jpn J Thorac Cardiovasc Surg, 2003 Jan, 51(1), 16 - 7 Salmonella pericarditis in a patient with primary idiopathic chylopericardium; Yoshioka H et al.; We report a case of a 40-year-old man with chylopericardium who developed purulent pericarditis caused by Salmonella enteritidis . Thoracoscopic pericardiotomy with debridement effectively controlled the pericardial infection. J Bacteriol, 2003 Apr, 185(7), 2330 - 7 Comparative genomics of Salmonella enterica serovar Typhi strains Ty2 and CT18; Deng W et al.; We present the 4.8-Mb complete genome sequence of Salmonella enterica serovar Typhi strain Ty2, a human-specific pathogen causing typhoid fever . A comparison with the genome sequence of recently isolated S . enterica serovar Typhi strain CT18 showed that 29 of the 4,646 predicted genes in Ty2 are unique to this strain, while 84 genes are unique to CT18 . Both genomes contain more than 200 pseudogenes; 9 of these genes in CT18 are intact in Ty2, while 11 intact CT18 genes are pseudogenes in Ty2 . A half-genome interreplichore inversion in Ty2 relative to CT18 was confirmed . The two strains exhibit differences in prophages, insertion sequences, and island structures . While CT18 carries two plasmids, one conferring multiple drug resistance, Ty2 has no plasmids and is sensitive to antibiotics. J Bacteriol, 2003 Apr, 185(7), 2131 - 42 Genomic diversification among archival strains of Salmonella enterica serovar typhimurium LT7; Liu GR et al.; To document genomic changes during long periods of storage, we analyzed Salmonella enterica serovar Typhimurium LT7, a mutator strain that was previously reported to have higher rates of mutations compared to other serovar Typhimurium strains such as LT2 . Upon plating directly from sealed agar stabs that had been stocked at room temperature for up to four decades, many auxotrophic mutants derived from LT7 gave rise to colonies of different sizes . Restreaking from single colonies consistently yielded colonies of diverse sizes even when we repeated single-colony isolation nine times . Colonies from the first plating had diverse genomic changes among and even within individual vials, including translocations, inversions, duplications, and point mutations, which were detected by rare-cutting endonuclease analysis with pulsed-field gel electrophoresis . Interestingly, even though the colony size kept diversifying, all descendents of the same single colonies from the first plating had the same sets of detected genomic changes . We did not detect any colony size or genome structure diversification in serovar Typhimurium LT7 stocked at -70 degrees C or in serovar Typhimurium LT2 stocked either at -70 degrees C or at room temperature . These results suggest that, although colony size diversification occurred during rapid growth, all detected genomic changes took place during the storage at room temperature and were carried over to their descendents without further changes during rapid growth in rich medium . We constructed a genomic cleavage map on the LT7 strain that had been stocked at -70 degrees C and located all of the detected genomic changes on the map . We speculated on the significance of mutators for survival and evolution under environmentally stressed conditions. Emerg Infect Dis, 2003 Mar, 9(3), 323 - 8 Emergence of ceftriaxone-resistant Salmonella isolates and rapid spread of plasmid-encoded CMY-2-like cephalosporinase, Taiwan; Yan JJ et al.; Of 384 Salmonella isolates collected from 1997 to 2000 in a university hospital in Taiwan, six ceftriaxone-resistant isolates of Salmonella enterica serovar Typhimurium were found in two patients in 2000 . The resistance determinants were on conjugative plasmids that encoded a CMY-2-like cephalosporinase . During the study period, the proportion of CMY-2-like enzyme producers among Escherichia coli increased rapidly from 0.2% in early 1999 to >4.0% in late 2000 . Klebsiella pneumoniae isolates producing a CMY-2-like beta-lactamase did not emerge until 2000 . The presence of bla(CMY)-containing plasmids with an identical restriction pattern from Salmonella, E . coli, and K . pneumoniae isolates was found, which suggests interspecies spread and horizontal transfer of the resistance determinant . Various nosocomial and community-acquired infections were associated with the CMY-2-like enzyme producers . Our study suggests that the spread of plasmid-mediated CMY-2-like beta-lactamases is an emerging threat to hospitalized patients and the public in Taiwan. East Afr Med J, 2002 Jun, 79(6), 317 - 22 Mycoplasma pneumoniae in children with pneumonia at Mbagathi District Hospital, Nairobi; Bii CC et al.; OBJECTIVE: To determine the prevalence of mycoplasma pneumoniae in nasophar