| biochemical evidence that the pdus gene encodes a bifunctional cobalamin reductase. | salmonella enterica degrades 1,2-propanediol (1,2-pd) by a pathway that requires coenzyme b(12) (adenosylcobalamin; adocbl). the genes specifically involved in 1,2-pd utilization (pdu) are found in a large contiguous cluster, the pdu locus. earlier studies have indicated that this locus includes genes for the conversion of vitamin b(12) (cyanocobalamin; cncbl) to adocbl and that the pduo gene encodes an atp : cob(i)alamin adenosyltransferase which catalyses the terminal step of this process. her ... | 2005 | 15817784 |
| characterization of the rdar morphotype, a multicellular behaviour in enterobacteriaceae. | the rdar morphotype, a multicellular behaviour of salmonella enterica and escherichia coli is characterized by the expression of the adhesive extracellular matrix components cellulose and curli fimbriae. the response regulator csgd, which transcriptionally activates the biosynthesis of the exopolysaccharide cellulose and curli, also transforms cell physiology to the multicellular state. however, the only role of csgd in cellulose biosynthesis is the activation of adra, a ggdef domain protein tha ... | 2005 | 15818467 |
| the alternative sigma factor sigma is required for resistance of salmonella enterica serovar typhimurium to anti-microbial peptides. | the enteric pathogen salmonella enterica serovar typhimurium (s. typhimurium) encounters a variety of anti-microbial peptides during the course of infection. we report here that the extracytoplasmic sigma factor sigma(e) (rpoe) is required for salmonella resistance to killing by the bactericidal/permeability-increasing protein (bpi)-derived peptide p2 and the murine alpha-defensin cryptdin-4 (crp4). moreover, sigma(e)-deficient s. typhimurium is attenuated for virulence after oral infection of i ... | 2005 | 15819632 |
| alternative sigma factor interactions in salmonella: sigma and sigma promote antioxidant defences by enhancing sigma levels. | hierarchical interactions between alternative sigma factors control sequential gene expression in gram-positive bacteria, whereas alternative sigma factors in gram-negative bacteria are generally regarded to direct expression of discrete gene subsets. in salmonella enterica serovar typhimurium (s. typhimurium), sigma(e) responds to extracytoplasmic stress, whereas sigma(h) responds to heat shock and sigma(s) is induced during nutrient limitation. deficiency of sigma(e), sigma(h) or sigma(s) incr ... | 2005 | 15819634 |
| factors associated with variation in bulk-tank-milk salmonella dublin elisa odc% in dairy herds. | our objective was to determine factors that contribute to variation in bulk-tank-milk salmonella dublin enzyme-linked immunosorbent assays (elisa) corrected optic-density measurements (odc%) in dairy herds. we constructed hierarchical mixed models with repeated bulk-tank-milk elisa odc% in 31 danish dairy herds. four models included different combinations of explanatory factors, and we compared how well these models described the variation in the data. herd was included as a random effect nested ... | 2005 | 15820114 |
| differential contribution of sodc1 and sodc2 to intracellular survival and pathogenicity of salmonella enterica serovar choleraesuis. | several of the most virulent salmonella enterica strains possess two genes encoding periplasmic cu,zn superoxide dismutase, sodc1 and sodc2, located on a lambdoid prophage and on the chromosome, respectively. these genes contribute to salmonella virulence by protecting bacteria from superoxide generated by the host's phagocytes. to investigate the respective contributions of sodc1 and sodc2 to the virulence of a clinical isolate of salmonella enterica serovar choleraesuis (s. choleraesuis), we h ... | 2005 | 15823516 |
| invasive infection with multidrug-resistant salmonella enterica serotype typhimurium definitive type 104 among hiv-infected adults. | multidrug-resistant salmonella enterica serotype typhimurium definitive type 104 (mrdt104), with resistance to at least ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline (r-type acssut), was first detected in the united states in 1985, and the prevalence increased to account for nearly 7% of salmonella infections in 1998. | 2005 | 15824994 |
| multidrug-resistant shigella sonnei and salmonella enterica serotype typhimurium isolates producing ctx-m beta-lactamases as causes of community-acquired infection in france. | | 2005 | 15825010 |
| purification and characterization of deacylated and/or palmitoylated lipid a species unique to salmonella enterica serovar typhimurium. | the salmonella enterica serovar typhimurium virulence gene products phop/phoq sense host microenvironments to regulate the expression of a lipid a 3-o-deacylase, pagl, and a lipid a palmitoyltransferase, pagp. therefore, deacylation and/or palmitoylation of lipid a could occur in salmonellae adapted to host environments. the phop/phoq-regulated modification of lipid a alters host recognition and signaling, and may play an important role in host defense against salmonellae infection. here we repo ... | 2005 | 15826380 |
| web-based investigation of multistate salmonellosis outbreak. | we investigated a large outbreak of salmonella enterica serotype javiana among attendees of the 2002 u.s. transplant games, including 1,500 organ transplant recipients. web-based survey methods identified pre-diced tomatoes as the source of this outbreak, which highlights the utility of such investigative tools to cope with the changing epidemiology of foodborne diseases. | 2005 | 15829202 |
| thermal resistance of salmonella enterica serotypes, listeria monocytogenes, and staphylococcus aureus in high solids liquid egg mixes. | decimal reduction times (d-values) were determined for salmonella enterica serotypes, listeria monocytogenes, and staphylococcus aureus in two high solids egg mixes designated a and b (water activity [a(w)] = 0.76 and 0.82; solids = 53.12 and 52.63%; ph = 5.09 and 5.29; viscosity = 183 and 119 centipoise/s, respectively) using a low-volume (0.06 ml) sealed glass capillary tube procedure. for salmonella, d-values ranged from 0.035 (70 degrees c) to 0.193 min (64 degrees c) in product a and from 0 ... | 2005 | 15830659 |
| inactivation of salmonella enterica serovar enteritidis on shell eggs by ozone and uv radiation. | the presence of salmonella enterica serovar enteritidis in shell eggs has serious public health implications. several treatments have been developed to control salmonella on eggs with mixed results. currently, there is a need for time-saving, economical, and effective egg sanitization treatments. in this study, shell eggs externally contaminated with salmonella (8.0 x 10(5) to 4.0 x 10(6) cfu/g of eggshell) were treated with gaseous ozone (o3) at 0 to 15 lb/in2 gauge for 0 to 20 min. in other ex ... | 2005 | 15830660 |
| growth of salmonella enterica serovar enteritidis in albumen and yolk contents of eggs inoculated with this organism onto the vitelline membrane. | by using an in vitro model simulating the potential opportunities for salmonella enterica serovar enteritidis (se) to proliferate within eggs contaminated with this organism following oviposition, we investigated growth of se in eggs. seventy to 140 cfu of one of three se strains originating either from egg contents, chicken meat, or a human infection were experimentally inoculated onto the vitelline membrane of eggs collected from specific-pathogen-free flocks of chickens and incubated at 25 de ... | 2005 | 15830661 |
| destruction of salmonella senftenberg on the shells of intact eggs by thermoultrasonication. | the combined effect of ultrasonic waves and heat treatment applied simultaneously was evaluated on the survival of strains of salmonella senftenberg on shells of intact eggs. this combined process has a higher killing effect than heat treatment alone. the decimal reduction times (d-values) were decreased by 65.2 to 11.1% in the temperature range studied (57.8 to 67 degrees c). in contrast to the effect on salmonella enterica serovar enteritidis in a previous study, thermoultrasonication had no i ... | 2005 | 15830681 |
| effectiveness of trisodium phosphate treatment against pathogenic and spoilage bacteria on poultry during refrigerated storage. | to determine the efficacy of trisodium phosphate (tsp) against pathogenic and spoilage bacteria on poultry and to assess the influence of the bacterial combination of inoculum on tsp effect, chicken legs were coinoculated with similar concentrations of a pathogenic (salmonella enterica ser. enteritidis or listeria monocytogenes) and a spoilage (pseudomonas fluorescens or brochothrix thermosphacta) bacteria. samples were dipped in tsp (12%, 15 min) or were not treated (control). microbiological a ... | 2005 | 15830686 |
| a randomized comparison of oral chloramphenicol versus ofloxacin in the treatment of uncomplicated typhoid fever in laos. | we conducted a randomized open trial of oral chloramphenicol (50mg/kg/day in four divided doses for 14 days) versus ofloxacin (15 mg/kg/day in two divided doses for 3 days) in 50 adults with culture-confirmed uncomplicated typhoid fever in vientiane, laos. patients had been ill for a median (range) of 8 (2-30) days. all salmonella enterica serotype typhi isolates were nalidixic acid-sensitive, four (8%) were chloramphenicol-resistant and three (6%) were multidrug-resistant. median (range) fever ... | 2005 | 15837357 |
| precise excision and secondary transposition of tnphoa in non-motile mutants of a salmonella enterica serovar enteritidis clinical isolate. | mutagenesis with tnphoa has been widely used in many bacteria. here, we report the excision and secondary transposition of this transposon in three non-motile (flic, flif and motb) mutants of salmonella enterica serovar enteritidis (s. enteritidis). isolation of motile revertants showed that they were kanamycin resistant and conserved a copy of tnphoa in their genome in an insertion site different from the initial one. they also expressed an intact flagella. characterization of the motile revert ... | 2005 | 15837381 |
| functional characterization of waal, a ligase associated with linking o-antigen polysaccharide to the core of pseudomonas aeruginosa lipopolysaccharide. | the o antigen of pseudomonas aeruginosa b-band lipopolysaccharide is synthesized by assembling o-antigen-repeat units at the cytoplasmic face of the inner membrane by nonprocessive glycosyltransferases, followed by polymerization on the periplasmic face. the completed chains are covalently attached to lipid a core by the o-antigen ligase, waal. in p. aeruginosa the process of ligating these o-antigen molecules to lipid a core is not clearly defined, and an o-antigen ligase has not been identifie ... | 2005 | 15838026 |
| polyphosphate kinase protects salmonella enterica from weak organic acid stress. | mutants of salmonella enterica lacking polyphosphate kinase (ppk) grow poorly in the presence of the weak organic acids acetate, propionate, and benzoate. this sensitivity is corrected by methionine and seems to result from destabilization of meta (homoserine transsuccinylase), the first enzyme in methionine biosynthesis. the meta protein is known to be sensitive to thermal inactivation, and ppk mutants are more sensitive to heat-induced methionine auxotrophy. peroxide increases the sensitivity ... | 2005 | 15838036 |
| exopolysaccharide sugars contribute to biofilm formation by salmonella enterica serovar typhimurium on hep-2 cells and chicken intestinal epithelium. | recently, we demonstrated that salmonella enterica serovar typhimurium can form biofilm on hep-2 cells in a type 1 fimbria-dependent manner. previous work on salmonella exopolysaccharide (eps) in biofilm indicated that the eps composition can vary based upon the substratum on which the bacterial biofilm forms. we have investigated the role of genes important in the production of colanic acid and cellulose, common components of eps. a mutation in the colanic acid biosynthetic gene, wcam, was intr ... | 2005 | 15838049 |
| a reduced level of charged trnaargmnm5ucu triggers the wild-type peptidyl-trna to frameshift. | frameshift mutations can be suppressed by a variety of differently acting external suppressors. the +1 frameshift mutation hisc3072, which has an extra g in a run of gs, is corrected by the external suppressor mutation suff44. we have shown that suff44 and five additional allelic suppressor mutations are located in the gene argu coding for the minor trnaargmnm5ucu and alter the secondary and/or tertiary structure of this trna. the c61u, g53a, and c32u mutations influence the stability, whereas t ... | 2005 | 15840821 |
| macrophage cell death due to salmonella enterica serovar typhi and its acid stress protein has features of apoptosis. | salmonella spp. have been shown to cause apoptosis of various host cell types as a part of their infection process. however, the induction of apoptosis remains to be looked into under the different host environments including acidic stress experienced by the pathogen. in order to simulate the in vivo acidic conditions, we studied the potential of s. typhi and its protein expressed under in vitro acidic conditions to induce apoptosis in macrophages. murine macrophages were isolated and interacted ... | 2005 | 15840957 |
| genetic and molecular analysis of gogb, a phage-encoded type iii-secreted substrate in salmonella enterica serovar typhimurium with autonomous expression from its associated phage. | salmonella enterica serovar typhimurium is lysogenized by several temperate bacteriophages that encode lysogenic conversion genes, which can act as virulence factors during infection and contribute to the genetic diversity and pathogenic potential of the lysogen. we have investigated the temperate bacteriophage called gifsy-1 in s.enterica serovar typhimurium and show here that the product of the gogb gene encoded within this phage shares similarity with proteins from other gram-negative pathoge ... | 2005 | 15843015 |
| eliminating the carriage of salmonella enterica serovar enteritidis in domestic fowls by feeding activated charcoal from bark containing wood vinegar liquid (nekka-rich). | the protective efficacy of activated charcoal containing wood vinegar liquid (nekka-rich) against intestinal infection with salmonella enterica serovar enteritidis was sought. in the present study, the adsorption effects of activated charcoal of nekka-rich on s. enteritidis and normal bacterial flora in the intestine, enterococcus faecium, were examined. s. enteritidis was effectively adsorbed by activated charcoal of nekka-rich. on the other hand, activated charcoal of nekka-rich showed lower b ... | 2005 | 15844805 |
| emergence of salmonella epidemics: the problems related to salmonella enterica serotype enteritidis and multiple antibiotic resistance in other major serotypes. | two major changes in the epidemiology of salmonellosis occurred in the second half of the 20th century: the emergence of food-borne human infections caused by s. enteritidis and by multiple-antibiotic resistant strains of salmonella. this review updates information on the s. enteritidis pandemic and focuses on the emergence of salmonella, carrying the sgi1 antibiotic resistance gene cluster, resistant to extended-spectrum cephalosporins, or resistant to fluoroquinolones. the factors responsible ... | 2005 | 15845226 |
| characterization of salmonella-induced cell death in human macrophage-like thp-1 cells. | salmonella strains are facultative intracellular pathogens that produce marked cytopathology during infection of host cells. different forms of cytopathic effects have been associated with the virulence systems encoded by the two salmonella pathogenicity islands (spi-1 and spi-2) and the spv locus. we used salmonella enterica serovar dublin to investigate the induction of cytopathology during infection of the human macrophage-like cell line thp-1. analysis of host cells by flow cytometry using a ... | 2005 | 15845488 |
| gamma irradiation or cd4+-t-cell depletion causes reactivation of latent salmonella enterica serovar typhimurium infection in c3h/hen mice. | upon infection with salmonella, a host develops an immune response to limit bacterial growth and kill and eliminate the pathogen. salmonella has evolved mechanisms to remain dormant within the body, only to reappear (reactivate) at a later time when the immune system is abated. we have developed an in vivo model for studying reactivation of salmonella enterica serovar typhimurium infection in mice. upon subcutaneous infection, c3h/hen (ity(r)) mice showed an increase in bacterial numbers in live ... | 2005 | 15845491 |
| differential induction of the toll-like receptor 4-myd88-dependent and -independent signaling pathways by endotoxins. | the biological response to endotoxin mediated through the toll-like receptor 4 (tlr4)-md-2 receptor complex is directly related to lipid a structure or configuration. endotoxin structure may also influence activation of the myd88-dependent and -independent signaling pathways of tlr4. to address this possibility, human macrophage-like cell lines (thp-1, u937, and mm6) or murine macrophage raw 264.7 cells were stimulated with picomolar concentrations of highly purified endotoxins. harvested supern ... | 2005 | 15845500 |
| infection of the reproductive tract and eggs with salmonella enterica serovar pullorum in the chicken is associated with suppression of cellular immunity at sexual maturity. | salmonella enterica serovar pullorum causes persistent infections in laying hens. splenic macrophages are the main site of persistence. at sexual maturity, numbers of bacteria increase and spread to the reproductive tract, which may result in vertical transmission to eggs or chicks. in this study we demonstrate that both male and female chickens may develop a carrier state following infection but that the increases in bacterial numbers and spread to the reproductive tract are phenomena restricte ... | 2005 | 15845505 |
| requirement of mgtc for brucella suis intramacrophage growth: a potential mechanism shared by salmonella enterica and mycobacterium tuberculosis for adaptation to a low-mg2+ environment. | a brucella suis mgtc mutant is defective for growth within macrophages and in low-mg(2+) medium. these phenotypes are strikingly similar to those observed with mgtc mutants from salmonella enterica and mycobacterium tuberculosis, two other pathogens that proliferate within phagosomes. mgtc appears as a remarkable virulence factor that would have been acquired by distantly related intracellular pathogens to contribute to the adaptation to a low-mg(2+) environment in the phagosome. | 2005 | 15845525 |
| mccj25 c-terminal is involved in rna-polymerase inhibition but not in respiration inhibition. | microcin j25 appears to have two intracellular targets: (1) rna polymerase, which was described in escherichia coli and salmonella enterica serovars, and (2) cell respiration in salmonella enterica serovars. c-terminal glycine amidation of the threaded segment localized in the mccj25 lariat ring region specifically blocked the rna-polymerase inhibition, but not the cell respiration inhibition and peptide uptake. these results suggest that different regions of the molecule are responsible for eac ... | 2005 | 15850794 |
| systemic administration of attenuated salmonella choleraesuis in combination with cisplatin for cancer therapy. | some anaerobic and facultative anaerobic bacteria have been employed as anticancer agents. previously, we have demonstrated tumor-targeting and antitumor activities of attenuated salmonella choleraesuis carrying antiangiogenic genes. here we exploited s. choleraesuis as a single-agent therapy and as part of a combination therapy with low-dose cisplatin for syngeneic murine lung tumor and hepatoma. systemically injected s. choleraesuis preferentially accumulated within tumors for at least 4 weeks ... | 2005 | 15851009 |
| compensatory role of pspa, a member of the phage shock protein operon, in rpoe mutant salmonella enterica serovar typhimurium. | sigma(e) is an alternative sigma factor that responds to and ameliorates extracytoplasmic stress. in salmonella enterica serovar typhimurium (s. typhimurium), sigma(e) is required for oxidative stress resistance, stationary-phase survival and virulence in mice. microarray analysis of stationary-phase gene expression in rpoe mutant bacteria revealed a dramatic increase in expression of pspa, a member of the phage shock protein (psp) operon. the psp operon can be induced by filamentous bacteriopha ... | 2005 | 15853886 |
| genetic environment and expression of the extended-spectrum beta-lactamase blaper-1 gene in gram-negative bacteria. | the genetic location of the gene coding for the expanded-spectrum beta-lactamase per-1 was analyzed in a series of gram-negative isolates. it was identified as part of a composite transposon bracketed by two novel insertion elements, ispa12 and ispa13, belonging to the is4 family that possess transposases that share 63% amino acid identity and that are chromosomally located in pseudomonas aeruginosa, providencia stuartii, and acinetobacter baumannii. on the contrary, the bla(per-1) gene was iden ... | 2005 | 15855485 |
| application of an in vitro infection model and simulation for reevaluation of fluoroquinolone breakpoints for salmonella enterica serotype typhi. | salmonella enterica serotype typhi and nontyphoidal salmonella remain major causes of morbidity and mortality worldwide. ampicillin, trimethoprim-sulfamethoxazole, and chloramphenicol no longer provide reliable coverage of salmonella, and fluoroquinoloes have emerged as first-line treatment options. due to mounting evidence of decreased in vitro susceptibility and diminished clinical response to fluoroquinolone therapy, it has been suggested that the nccls breakpoints for the salmonellae be reev ... | 2005 | 15855495 |
| salmonella enterica serovar infantis producing a ctx-m-9 beta-lactamase. | | 2005 | 15855550 |
| a "gain of function" mutation in a protein mediates production of novel modified nucleosides. | the mutation sufy204 mediates suppression of a +1 frameshift mutation in the histidine operon of salmonella enterica serovar typhimurium and synthesis of two novel modified nucleosides in trna. the sufy204 mutation, which results in an amino-acid substitution in a protein, is, surprisingly, dominant over its wild-type allele and thus it is a "gain of function" mutation. one of the new nucleosides is 5-methylaminomethyl-2-thiouridine (mnm(5)s(2)u34) modified by addition of a c(10)h(17) side chain ... | 2005 | 15861125 |
| salmonella isolates from wild birds and mammals in the basque country (spain). | the authors investigated the prevalence of salmonella spp. in 205 wild birds and mammals belonging to 45 species during the years 2001 and 2002 in the basque country (spain). salmonella was isolated from 16 (7.8%) animals. the prevalence was 8.5% (7/82) in birds, and 7.2% (9/123) in mammals. nine serotypes, all of them belonging to the species salmonella enterica, were identified: two isolates of typhimurium (from 1/3 griffon vultures [gyps fulvus], and 1/5 sparrowhawks [accipiter nisus]); one o ... | 2004 | 15861885 |
| the product of the qacc gene of staphylococcus epidermidis ch mediates resistance to beta-lactam antibiotics in gram-positive and gram-negative bacteria. | we have characterized a natural isolate of staphylococcus epidermidis resistant to heavy metals that carries a small 2391-bp plasmid, psepch, encoding the qacc gene. the s. epidermidis qacc gene confers resistance to a number of beta-lactam antibiotics and to ethidium bromide in its natural host and in escherichia coli k12 and salmonella enterica sv. typhimurium. this is the first communication of a small multidrug resistance (smr) pump involved in resistance to beta-lactam antibiotics. experime ... | 2005 | 15862444 |
| persistence of escherichia coli o157:h7, salmonella newport, and salmonella poona in the gut of a free-living nematode, caenorhabditis elegans, and transmission to progeny and uninfected nematodes. | a study was undertaken to determine the persistence of escherichia coli o157:h7 and salmonellae in the gut of a free-living nematode, caenorhabditis elegans, as affected by temperature and relative humidity and to determine if infected worms transmit salmonella enterica serotype newport to progeny and uninfected worms. worms were fed cells of a non-pathogenic strain of e. coli (op50), e. coli o157:h7, s. enterica serotype newport, and s. enterica serotype poona, followed by incubating at 4, 20, ... | 2005 | 15862884 |
| defective o-antigen polymerization in tola and pal mutants of escherichia coli in response to extracytoplasmic stress. | we have previously shown that the tola protein is required for the correct surface expression of the escherichia coli o7 antigen lipopolysaccharide (lps). in this work, delta tola and delta pal mutants of e. coli k-12 w3110 were transformed with pmf19 (encoding a rhamnosyltransferase that reconstitutes the expression of o16-specific lps), pwq5 (encoding the klebsiella pneumoniae o1 lps gene cluster), or pwq802 (encoding the genes necessary for the synthesis of salmonella enterica o:54). both del ... | 2005 | 15866920 |
| identification of cpta, a pmra-regulated locus required for phosphoethanolamine modification of the salmonella enterica serovar typhimurium lipopolysaccharide core. | in response to the in vivo environment, the salmonella enterica serovar typhimurium lipopolysaccharide (lps) is modified. these modifications are controlled in part by the two-component regulatory system pmra-pmrb, with the addition of 4-aminoarabinose (ara4n) to the lipid a and phosphoethanolamine (petn) to the lipid a and core. here we demonstrate that the pmra-regulated stm4118 (cpta) gene is necessary for the addition of petn to the lps core. pmrc, a pmra-regulated gene necessary for the add ... | 2005 | 15866924 |
| mechanisms of strand replacement synthesis for plasmid dna transferred by conjugation. | a single strand of plasmid dna is transferred during conjugation. we examined the mechanism of complementary strand synthesis in recipient cells following conjugative mobilization of derivatives of the incq plasmid r1162. a system for electroporation of donor cells, followed by immediate mating, was used to eliminate plasmid-specific replicative functions. under these conditions, escherichia coli recipients provided a robust mechanism for initiation of complementary strand synthesis on transferr ... | 2005 | 15866925 |
| the salmonella translocated effector sopa is targeted to the mitochondria of infected cells. | this study investigates the salmonella effector protein sopa. we show that in salmonella enterica serovar dublin-infected cells, sopa(1-347) fused to two carboxy-terminal hemagglutinin tags partially colocalized with mitochondria. transfection of eukaryotic cells with a panel of constructs encoding truncated versions of sopa identified that amino acids 100 to 347 were sufficient to target sopa to the mitochondria. | 2005 | 15866946 |
| potential role of diploscapter sp. strain lkc25, a bacterivorous nematode from soil, as a vector of food-borne pathogenic bacteria to preharvest fruits and vegetables. | diploscapter, a thermotolerant, free-living soil bacterial-feeding nematode commonly found in compost, sewage, and agricultural soil in the united states, was studied to determine its potential role as a vehicle of salmonella enterica serotype poona, enterohemorrhagic escherichia coli o157:h7, and listeria monocytogenes in contaminating preharvest fruits and vegetables. the ability of diploscapter sp. strain lkc25 to survive on agar media, in cow manure, and in composted turkey manure and to be ... | 2005 | 15870330 |
| clonal expansion may account for high levels of quinolone resistance in salmonella enterica serovar enteritidis. | we have observed a high incidence of isolated nalidixic acid resistance in salmonella enterica serovar enteritidis isolates in ireland, particularly isolates of phage type 1 (pt1). a group of nalidixic acid-resistant (n = 22) and nalidixic acid-susceptible (n = 28) isolates of serovar enteritidis from multiple sites in ireland were selected. isolates were typed by pulsed-field gel electrophoresis (pfge) with xbai, and the mics for nalidixic acid and ciprofloxacin were determined. mutations assoc ... | 2005 | 15870349 |
| production of autoinducer 2 in salmonella enterica serovar thompson contributes to its fitness in chickens but not on cilantro leaf surfaces. | food-borne illness caused by salmonella enterica has been linked traditionally to poultry products but is associated increasingly with fresh fruits and vegetables. we have investigated the role of the production of autoinducer 2 (ai-2) in the ability of s. enterica serovar thompson to colonize the chicken intestine and the cilantro phyllosphere. a mutant of s. enterica serovar thompson that is defective in ai-2 production was constructed by insertional mutagenesis of luxs. the population size of ... | 2005 | 15870357 |
| sensitivity of planktonic and biofilm-associated salmonella spp. to ionizing radiation. | salmonella enterica forms biofilms that are relatively resistant to chemical sanitizing treatments. ionizing radiation has been used to inactivate salmonella on a variety of foods and contact surfaces, but the relative efficacy of the process against biofilm-associated cells versus free-living planktonic cells is not well documented. the radiation sensitivity of planktonic or biofilm-associated cells was determined for three food-borne-illness-associated isolates of salmonella. biofilms were for ... | 2005 | 15870365 |
| dose determination for acute salmonella infection in pigs. | pigs were exposed to various levels of salmonella enterica subsp. enterica serovar typhimurium by either intranasal inoculation or by subjecting them to a contaminated environment. more than 10(3) salmonellae were required to induce acute salmonella infection. these results indicate that intervention against acute salmonella infection in lairage may be more readily achieved than previously thought. | 2005 | 15870368 |
| increasing ceftriaxone resistance in salmonella isolates from a university hospital in taiwan. | salmonella infection is a distressing health problem worldwide. this study reports the changing epidemiology of salmonella infections in taiwan during 1999-2003, with emphasis on increasing ceftriaxone resistance. | 2005 | 15872047 |
| multilocus sequence typing lacks the discriminatory ability of pulsed-field gel electrophoresis for typing salmonella enterica serovar typhimurium. | nontyphoidal salmonellae are among the leading causes of food-borne disease in the united states. because of the importance of salmonella enterica in food-borne disease, numerous typing methodologies have been developed. among the several molecular typing methods, pulsed-field gel electrophoresis (pfge) is currently considered the "gold standard" technique in typing salmonella. the aim of this study was to compare the discriminatory power of pfge to multilocus sequence typing (mlst) in typing sa ... | 2005 | 15872244 |
| characterization of ampc-mediated resistance in clinical salmonella isolates recovered from humans during the period 1992 to 2003 in england and wales. | the increase in ampc-mediated resistance in salmonellae constitutes a serious public health concern, since these enzymes confer resistance to a wide range of beta-lactams. one hundred six isolates were selected from 278,308 salmonella isolates based on resistance to ampicillin and cephalosporins and were subjected to further characterization. nine isolates had a cefoxitin inhibition diameter < or = 17 mm and were proven to be ampc positive by multiplex pcr. sequence analysis revealed the presenc ... | 2005 | 15872253 |
| modulation of gut mucosal biofilms. | non-digestible inulin-type fructans, such as oligofructose and high-molecular-weight inulin, have been shown to have the ability to alter the intestinal microbiota composition in such a way that members of the microbial community, generally considered as health-promoting, are stimulated. bifidobacteria and lactobacilli are the most frequently targeted organisms. less information exists on effects of inulin-type fructans on the composition, metabolism and health-related significance of bacteria a ... | 2005 | 15877893 |
| rapid clearance of a recombinant salmonella vaccine carrier prevents enhanced antigen-specific cd8 t-cell responses after oral boost immunizations. | the type iii secretion system of salmonella enterica serovar typhimurium can be used to target heterologous antigens directly into the cytosol of antigen-presenting cells. our laboratory has previously reported that the single oral immunization of mice with a recombinant salmonella strain expressing the translocated yersinia outer protein e fused to the immunodominant antigen p60 from listeria monocytogenes results in the efficient induction of p60-specific cd8 t cells and confers protection aga ... | 2005 | 15878680 |
| switching aconitase b between catalytic and regulatory modes involves iron-dependent dimer formation. | in addition to being the major citric acid cycle aconitase in escherichia coli the aconitase b protein (acnb) is also a post-transcriptional regulator of gene expression. the acnb proteins represent a distinct branch of the aconitase superfamily that possess a heat-like domain (domain 5). the heat domains of other proteins are implicated in protein:protein interactions. gel filtration analysis has now shown that cell-free extracts contain high-molecular-weight species of acnb. furthermore, in vi ... | 2005 | 15882410 |
| interaction of the salmonella-containing vacuole with the endocytic recycling system. | upon entry of the pathogen salmonella enterica serovar typhimurium into host cells, the majority of bacteria reside in a membrane-bound compartment called the salmonella-containing vacuole (scv). previous studies have established that the scv transiently interacts with early endosomes but only acquires a subset of late endosomal/lysosomal proteins. however, the complete set of interactions between the scv and the endocytic machinery has yet to be characterized. in this study, we have shown that ... | 2005 | 15886200 |
| outbreak of multidrug-resistant salmonella typhimurium associated with rodents purchased at retail pet stores--united states, december 2003-october 2004. | during 2004, the minnesota department of health (mdh) public health laboratory notified cdc about the isolation of multidrug-resistant salmonella enterica serotype typhimurium from ill hamsters from a minnesota pet distributor. this report describes two of the first identified human cases associated with this outbreak, summarizes the multistate investigation of human s. typhimurium infections associated with exposure to rodents (e.g., hamsters, mice, and rats) purchased at pet stores, and highli ... | 2005 | 15889011 |
| formation of a novel surface structure encoded by salmonella pathogenicity island 2. | the type iii secretion system (t3ss) encoded by salmonella pathogenicity island 2 (spi2) is essential for virulence and intracellular proliferation of salmonella enterica. we have previously identified spi2-encoded proteins that are secreted and function as a translocon for the injection of effector proteins. here, we describe the formation of a novel spi2-dependent appendage structure in vitro as well as on the surface of bacteria that reside inside a vacuole of infected host cells. in contrast ... | 2005 | 15889142 |
| salmonella derby clonal spread from pork. | the genetic diversity of the derby serotype of salmonella enterica in spain was examined by pulsed-field gel electrophoresis (pfge). out of 24 identified pfge profiles, a major clone was detected in 19% of strains from humans, 52% from food, and 62% from swine. this clone (clone 1) was isolated from pork products, suggesting swine as its source. | 2005 | 15890121 |
| host-pathogen interactions: a proteomic view. | host-pathogen interactions reflect the balance of host defenses and pathogen virulence mechanisms. advances in proteomic technologies now afford opportunities to compare protein content between complex biologic systems ranging from cells to animals and clinical samples. thus, it is now possible to characterize host-pathogen interactions from a global proteomic view. most reports to date focus on cataloging protein content of pathogens and identifying virulence-associated proteins or proteomic al ... | 2005 | 15892564 |
| biofilm formation, cellulose production, and curli biosynthesis by salmonella originating from produce, animal, and clinical sources. | the ability of 71 strains of salmonella enterica originating from produce, meat, or clinical sources to form biofilms was investigated. a crystal violet binding assay demonstrated no significant differences in biofilm formation by isolates from any source when tested in any of the following three media: luria-bertani broth supplemented with 2% glucose, tryptic soy broth (tsb), or 1/20th-strength tsb. incubation was overnight at 30 degrees c under static conditions. curli production and cellulose ... | 2005 | 15895720 |
| [class 1 integrons among salmonella enterica isolates producing different types of beta-lactamases from the health region of tortosa (spain)]. | to assess the frequency of class 1 integrons among isolates of salmonella enterica producing different types of beta-lactamases from the health region of tortosa, and to attempt to establish the resistance genes located within their variable regions. | 2005 | 15899175 |
| spatial distribution of antibodies to salmonella enterica serovar typhimurium o antigens in bulk milk from texas dairy herds. | environmental factors that enhance either the survivability or dispersion of salmonella enterica serovar typhimurium (s. typhimurium) could result in a spatial pattern of disease risk. the objectives of this study were to: (1) describe herd status based on antibody response to salmonella typhimurium as estimated from bulk tank milk samples and (2) to describe the resulting geographical patterns found among texas dairy herds. eight hundred and fifty-two bulk milk samples were collected from geore ... | 2005 | 15899296 |
| residue leu-641 of acetyl-coa synthetase is critical for the acetylation of residue lys-609 by the protein acetyltransferase enzyme of salmonella enterica. | posttranslational regulation of protein function by acetylation is present throughout nature. regulation of protein function by sir2 protein (sirtuin) deacetylases is conserved in all domains of life. in the prokaryote salmonella enterica, the metabolic enzyme acetyl-coenzyme a synthetase (acs) is regulated by a sir2-dependent protein acetylation/deacetylation system (sdpads). the recent identification of the acetyltransferase enzyme responsible for the acetylation of acs defined the sdpads in p ... | 2005 | 15899897 |
| [a case with fever of unknown origin during treatment for malaria: multi-drug resistant salmonella typhi infection]. | typhoid fever is an acute infectious disease caused by salmonella serotype typhi, leading to endemic or epidemic outbreaks in tropical/ subtropical countries (especially in india, southeast asia, central and south africa). in this report, a 27 years old male patient with malaria has been presented. the patient was diagnosed to have malaria while working in afghanistan, and received malaria treatment since one month. he admitted to our hospital because of still continuing high fever, and other co ... | 2005 | 15900841 |
| a gene encoding l-methionine gamma-lyase is present in enterobacteriaceae family genomes: identification and characterization of citrobacter freundii l-methionine gamma-lyase. | citrobacter freundii cells produce l-methionine gamma-lyase when grown on a medium containing l-methionine. the nucleotide sequence of the hybrid plasmid with a c. freundii ecori insert of about 3.0 kbp contained two open reading frames, consisting of 1,194 nucleotides and 1,296 nucleotides, respectively. the first one (denoted megl) encoded l-methionine gamma-lyase. the enzyme was overexpressed in escherichia coli and purified. the second frame encoded a protein belonging to the family of perme ... | 2005 | 15901718 |
| the intracellular fate of salmonella depends on the recruitment of kinesin. | salmonella enterica causes a variety of diseases, including gastroenteritis and typhoid fever. the success of this pathogen depends on its capacity to proliferate within host cells in a membrane-bound compartment. we found that the salmonella-containing vacuole recruited the plus-end-directed motor kinesin. bacterial effector proteins translocated into the host cell by a type iii secretion system antagonistically regulated this event. among these effectors, sifa targeted skip, a host protein tha ... | 2005 | 15905402 |
| identification and sequencing of salmonella enterica serotype typhi isolates obtained from patients with perforation and non-perforation typhoid fever. | we describe the characterization of salmonella enterica serovar typhi, isolated from the blood of patients with perforation and non-perforation typhoid fever, by a combination of conventional microbiological tests, 16s rrna gene sequencing, and flagellin gene and cdp-tyvelose epimerase (rfbe) gene sequencing. the 16s rrna gene sequencing showed that there were four base mutations from perforation samples and only three from non-perforation samples. these findings indicated that the isolates were ... | 2005 | 15906653 |
| cryptic plasmid prk2 from escherichia coli w: sequence analysis and segregational stability. | cryptic plasmid prk2 of the strain escherichia coli w (atcc 9637), an ancestor of production strains for penicillin g acylase, was sequenced and characterized. based on the data on replication region and origin (ori sequence aac, 924-926nt), the plasmid was classified as cole1-like plasmid. dna sequence analysis revealed five orfs hypothetical products of which shared a significant sequence similarity with putative proteins encoded by dna of plasmid pcole1. orf1 codes for protein rom involved in ... | 2005 | 15907542 |
| salmonella enterica serovar typhimurium pathogenicity island 2 is necessary for complete virulence in a mouse model of infectious enterocolitis. | salmonella species cause a wide range of disease in multiple hosts. salmonella enterica serovar typhimurium causes self-limited intestinal disease in humans and systemic typhoid-like illness in susceptible mice. the prevailing dogma in murine s. enterica serovar typhimurium pathogenesis is that distinct virulence mechanisms-salmonella pathogenicity islands 1 and 2 (spi1 and spi2)-perform distinct roles in pathogenesis, the former being important for invasion and intestinal disease and the latter ... | 2005 | 15908346 |
| comparison of salmonella enterica serovar typhimurium colitis in germfree mice and mice pretreated with streptomycin. | salmonella enterica subspecies 1 serovar typhimurium is a common cause of bacterial enterocolitis. mice are generally protected from salmonella serovar typhimurium colonization and enterocolitis by their resident intestinal microflora. this phenomenon is called "colonization resistance" (cr). two murine salmonella serovar typhimurium infection models are based on the neutralization of cr: (i) in specific-pathogen-free mice pretreated with streptomycin (strspf mice) antibiotics disrupt the intest ... | 2005 | 15908347 |
| the salmonella enterica serotype typhimurium lpf, bcf, stb, stc, std, and sth fimbrial operons are required for intestinal persistence in mice. | salmonella enterica serotype typhimurium causes human infections that can frequently be traced back through the food chain to healthy livestock whose intestine is colonized by the pathogen. little is known about the genes important for intestinal carriage of s. enterica serotype typhimurium in vertebrate animals. here we characterized the role of 10 fimbrial operons, agf, fim, lpf, pef, bcf, stb, stc, std, stf, and sth, using competitive infection experiments performed in genetically susceptible ... | 2005 | 15908362 |
| the vi capsular antigen of salmonella enterica serotype typhi reduces toll-like receptor-dependent interleukin-8 expression in the intestinal mucosa. | human infections with nontyphoidal salmonella serotypes, such as s. enterica serotype typhimurium, are characterized by a massive neutrophil influx in the colon and terminal ileum. in contrast, neutrophils are scarce in intestinal infiltrates of typhoid fever patients. here, we show that in s. enterica serotype typhi, the causative agent of typhoid fever, expression of the vi capsular antigen reduced expression of the neutrophil chemoattractant interleukin-8 (il-8) in host cells. capsulated bact ... | 2005 | 15908363 |
| gamma interferon enhances internalization and early nonoxidative killing of salmonella enterica serovar typhimurium by human macrophages and modifies cytokine responses. | gamma interferon (ifn-gamma) is a critical cytokine in host defense against salmonella infections, but its role in phagocytic killing of intracellular salmonella spp. has been investigated mainly in animal rather than human cells. we measured the effect of recombinant ifn-gamma (rifn-gamma) priming on bacterial internalization, intracellular killing, oxidative burst, and cytokine release during phagocytosis of salmonella enterica serovar typhimurium by human monocyte-derived macrophages (mdm). e ... | 2005 | 15908373 |
| immunization of volunteers with salmonella enterica serovar typhi strain ty21a elicits the oligoclonal expansion of cd8+ t cells with predominant vbeta repertoires. | cd8(+) t cells are likely to play an important role in host defense against salmonella enterica serovar typhi by several effector mechanisms, including lysis of infected cells (cytotoxicity) and gamma interferon (ifn-gamma) secretion. in an effort to better understand these responses, we studied the t-cell receptor (tcr) repertoire of serovar typhi-specific cd8(+) t cells in humans. to this end, we determined the tcr beta chain (vbeta) usage of cd8(+) t cells from three volunteers orally immuniz ... | 2005 | 15908381 |
| molecular and functional characterization of o antigen transfer in vibrio cholerae. | the majority of gram-negative bacteria transfer o antigen polysaccharides onto the lipid a-core oligosaccharide via the action of surface polymer:lipid a-core ligases (waal). here, we characterize the waal proteins of vibrio cholerae with emphasis on structural and functional characterization of o antigen transfer and core oligosaccharide recognition. we demonstrate that the activity of two distantly related o antigen ligases is dependent on the presence of n-acetylglucosamine, and substitution ... | 2005 | 15908430 |
| genetic basis of antimicrobial drug resistance in clinical isolates of salmonella enterica serotype hadar from a spanish region. | the genetic bases of antimicrobial drug resistance (r) of 79 salmonella enterica serotype hadar clinical isolates (recovered during 1995-2001 in a spanish region) was investigated. the isolates showed a limited genomic variation, as demonstrated by pfge analysis using xbai (three profiles, s>or=0.77) and blni (seven profiles, s>or=0.49; with 95% of the isolates falling into two clusters, s>or=0.75). thirteen r-profiles, ranging from susceptible to multidrug resistant, were recognized. all suscep ... | 2005 | 15910235 |
| identification of ctx-m-14 {beta}-lactamase in a salmonella enterica serovar enteritidis isolate from japan. | we analyzed the resistance to cefotaxime of a salmonella enterica serovar enteritidis isolate from a stool culture of a 4-year-old boy. it produced a beta-lactamase ctx-m-14, encoded by two related r plasmids. the region surrounding the blactx-m-14 gene had an original mosaic structure containing insertion sequences (is26 and is903d). | 2005 | 15917576 |
| problem pathogens: extra-intestinal complications of salmonella enterica serotype typhi infection. | typhoid fever, caused by salmonella enterica seroptype typhi (s typhi), has an estimated worldwide prevalence of 12-33 million cases. the pathogenesis of this disease depends on the ingested inoculum size of s typhi, the virulence of the strain, the host's immune response and previous exposure, and local protective factors. numerous extra-intestinal complications can occur with s typhi infection, including the involvement of the central nervous system (3-35%), cardiovascular system (1-5%), pulmo ... | 2005 | 15919620 |
| paneth cell alpha-defensins: peptide mediators of innate immunity in the small intestine. | epithelial cells contribute to innate immunity by releasing antimicrobial peptides (amps) onto mucosal surfaces. in the small bowel, paneth cells at the base of the crypts of lieberkühn secrete alpha-defensins and additional amps at high levels in response to cholinergic stimulation and when exposed to bacterial antigens. the release of paneth cell products into the crypt lumen is inferred to protect mitotically active crypt cells that renew the epithelial cell monolayer from colonization by pot ... | 2005 | 15931529 |
| identification of plasmids by pcr-based replicon typing. | the epidemiological importance of tracing plasmids conferring drug resistance prompted us to develop a pcr method based on replicons (inc/rep pcr) of the major plasmid incompatibility groups among enterobacteriaceae. eighteen pairs of primers were designed to perform 5 multiplex- and 3 simplex-pcrs, recognizing fia, fib, fic, hi1, hi2, i1-igamma, l/m, n, p, w, t, a/c, k, b/o, x, y, f, and fiia. the specificity of the method was tested on a collection of 61 reference plasmids and on 20 salmonella ... | 2005 | 15935499 |
| hyper-susceptibility of a fusidic acid-resistant mutant of salmonella to different classes of antibiotics. | fusidic acid resistance (fus(r)) in salmonella enterica serovar typhimurium is caused by mutations in fusa, encoding elongation factor g (ef-g). pleiotropic phenotypes are observed in fus(r) mutants. thus, the fusa1 allele (ef-g p413l) is associated with slow growth rate, reduced ppgpp and rpos levels, reduced heme levels, and increased sensitivity to oxidative stress. the fusa1-15 allele, (ef-g p413l and t423i) derived from fusa1 in a selection for growth rate compensation, is partially compens ... | 2005 | 15935566 |
| temperature-dependent conjugative transfer of r27: role of chromosome- and plasmid-encoded hha and h-ns proteins. | inchi plasmids encode multiple-antibiotic resistance in salmonella enterica serovar typhi. these plasmids have been considered to play a relevant role in the persistence and reemergence of this microorganism. the inchi1 plasmid r27, which can be considered the prototype of inchi plasmids, is thermosensitive for transfer. conjugation frequency is highest at low temperature (25 to 30 degrees c), decreasing when temperature increases. r27 codifies an h-ns-like protein (open reading frame 164 [orf16 ... | 2005 | 15937157 |
| characterization of gla(kp), a udp-galacturonic acid c4-epimerase from klebsiella pneumoniae with extended substrate specificity. | in escherichia coli and salmonella enterica, the core oligosaccharide backbone of the lipopolysaccharide is modified by phosphoryl groups. the negative charges provided by these residues are important in maintaining the barrier function of the outer membrane. in contrast, klebsiella pneumoniae lacks phosphoryl groups in its core oligosaccharide but instead contains galacturonic acid residues that are proposed to serve a similar function in outer membrane stability. gla(kp) is a udp-galacturonic ... | 2005 | 15937173 |
| the role of cd1d-restricted nk t lymphocytes in the immune response to oral infection with salmonella typhimurium. | cd1d-restricted natural killer t (nkt) cells belong to the innate-like lymphocytes which respond rapidly to stress and infectious challenge. we have studied murine cd1d-restricted nkt cells in the early immune response to virulent salmonella enterica serovar typhimurium after oral infection. in the liver and spleen, neutrophil and macrophage numbers had increased several-fold by day 5 post-infection, while the frequency of b and t lymphocytes decreased. these cellular changes occurred independen ... | 2005 | 15940666 |
| beta-lactamases among extended-spectrum beta-lactamase (esbl)-resistant salmonella from poultry, poultry products and human patients in the netherlands. | the purpose of this work was to study the genetic determinants responsible for extended-spectrum beta-lactamase (esbl) resistance of salmonella isolated from dutch poultry, poultry meat and hospitalized humans. | 2005 | 15941775 |
| oral immunization with a dam mutant of yersinia pseudotuberculosis protects against plague. | inactivation of the gene encoding dna adenine methylase (dam) has been shown to attenuate some pathogens such as salmonella enterica serovar typhimurium and is a lethal mutation in others such as yersinia pseudotuberculosis strain ypiii. in this study the dam methylase gene in yersinia pseudotuberculosis strain ip32953 was inactivated. unlike the wild-type, dna isolated from the mutant could be digested with mboi, which is consistent with an altered pattern of dna methylation. the mutant was sen ... | 2005 | 15941999 |
| the phop/phoq system controls the intramacrophage type three secretion system of salmonella enterica. | spi/ssa is a unique type three secretion system that functions exclusively when salmonella enterica is inside eukaryotic cells. expression of the spi/ssa system and its secreted effectors is dependent on ssrb/spir, a two-component regulatory system encoded in the spi-2 pathogenicity island that also harbours the spi/ssa genes. here we determine that the phop/phoq two-component system controls the intramacrophage expression of spi/ssa genes by regulating the ssrb/spir system. we establish that ph ... | 2005 | 15948951 |
| salmonella enterica serotype typhimurium misl is an intestinal colonization factor that binds fibronectin. | misl is an autotransporter protein encoded by salmonella pathogenicity island 3 (spi3). to investigate the role of misl in salmonella enterica serotype typhimurium (s. typhimurium) pathogenesis, we characterized its function during infection of mice and identified a host receptor for this adhesin. in a mouse model of s. typhimurium intestinal persistence, a misl mutant was shed with the faeces in significantly lower numbers than the wild type and was impaired in its ability to colonize the cecum ... | 2005 | 15948960 |
| antimicrobial activity of ultrasonic cleaners. | this study assessed the antimicrobial activity of two cleaning solutions and tap water after varying periods of use in one ultrasonic cleaner. testing involved filling the cleaner's tank and a centred glass beaker with the same test solution. an aluminium foil strip test first determined that no significant differences in cavitational activity existed inside the beaker compared with outside. standardized solutions of staphylococcus aureus, pseudomonas aeruginosa and salmonella choleraesuis were ... | 2005 | 15949617 |
| expanding the bactericidal action of the food color additive phloxine b to gram-negative bacteria. | phloxine b (d&c red no. 28) is a color additive for food, drugs, and cosmetics. it has been previously shown to have anti-staphylococcus aureus activities. in this work, the effect of phloxine b on various gram-negative bacteria and other gram-positive bacteria including bacillus cereus, bacillus thuringiensis, bacillus mycoides, bacillus subtilis, bacillus aureus, salmonella, escherichia coli and shigella was studied, along with the mechanism of anti-microbial activity. in the presence of fluor ... | 2005 | 15949926 |
| effect of alternative on-site wastewater treatment on the viability and culturability of salmonella choleraesuis. | the objective of this study was to determine how alternative on-site wastewater treatment systems (i.e. subsurface flow constructed wetlands, intermittent sand filters and intermittent peat filters) affect the viability and culturability of salmonella choleraesuis (serotype typhimurium, atcc 23567). influent was a high strength septic tank effluent (bod5 240-344 mgl(-1), tn approximately 100 mgl(-1), tp approximately 15 mgl(-1)) at the natural resources research institute's (nrri) alternative tr ... | 2005 | 15952448 |
| new concepts in salmonella virulence: the importance of reducing the intracellular growth rate in the host. | the literature refers to salmonella enterica as an intracellular bacterial pathogen that proliferates within vacuoles of mammalian cells. however, recent in vivo studies have revealed that the vast majority of infected cells contain very few intracellular bacteria (three to four organisms). salmonella intracellular growth is also limited in cultured dendritic cells and fibroblasts, two cell types abundant in tissues located underneath the intestinal epithelium. recently, a salmonella factor prev ... | 2005 | 15953023 |
| antimicrobial resistance of salmonella enterica group c strains isolated from humans in turkey, 2000-2002. | fifty-three salmonella enterica group c isolates obtained from various human samples (47 stool, 4 blood and 2 urine) in ten provinces of turkey between 1 july 2000 and 30 june 2002 were serotyped and resistance to antimicrobials was investigated by agar dilution tests. the isolates were identified as s. choleraesuis (11), s. hadar (7), s. irumu (4), s. virchow (3), s. tallahassee (3), s. paratyphi c (2), s. braenderup (2), s. othmarschen (2), s. menston (2), s. concord (2), s. infantis (2), s. k ... | 2005 | 15953709 |
| a study of the prevalence and enumeration of salmonella enterica in cattle and on carcasses during processing. | salmonella prevalence and counts were estimated for samples from the oral cavity, hide, rumen, and feces of 100 cattle at slaughter and from the pre- and postchill carcasses of these cattle. samples were collected from 25 consecutively slaughtered cattle from each of four unrelated groups slaughtered at a single abattoir on different days. ten additional fecal samples from each group were collected from their respective abattoir holding pens prior to slaughter. the prevalence of salmonella was e ... | 2005 | 15954700 |
| efficacy of gaseous chlorine dioxide as a sanitizer for killing salmonella, yeasts, and molds on blueberries, strawberries, and raspberries. | gaseous chlorine dioxide (clo2) was tested for its effectiveness in killing salmonella, yeasts, and molds on blueberries, strawberries, and red raspberries. an inoculum (100 microl, 6.0 to 6.8 log cfu/g of fruit) that contained five serotypes of salmonella enterica was deposited on the skin, calyx tissue, or stem scar tissue of blueberries, skin or stem scar tissue of strawberries, and skin of red raspberries, dried for 2 h at 22 degrees c, then held for 20 h at 4 degrees c and 2 h at 22 degrees ... | 2005 | 15954703 |
| evaluation of gaseous chlorine dioxide as a sanitizer for killing salmonella, escherichia coli o157:h7, listeria monocytogenes, and yeasts and molds on fresh and fresh-cut produce. | gaseous chlorine dioxide (clo2) was evaluated for effectiveness in killing salmonella, escherichia coli o157:h7, and listeria monocytogenes on fresh-cut lettuce, cabbage, and carrot and salmonella, yeasts, and molds on apples, peaches. tomatoes, and onions. inoculum (100 microl, ca. 6.8 log cfu) containing five serotypes of salmonella enterica, five strains of e. coli o157:h7, or five strains of l. monocytogenes was deposited on the skin and cut surfaces of fresh-cut vegetables, dried for 30 min ... | 2005 | 15954704 |
| chips and snps, bugs and thugs: a molecular sleuthing perspective. | recent events both here and abroad have focused attention on the need for ensuring a safe and secure food supply. although much has been written about the potential of particular select agents in bioterrorism, we must consider seriously the more mundane pathogens, especially those that have been implicated previously in foodborne outbreaks of human disease, as possible agents of bioterrorism. given their evolutionary history, the enteric pathogens are more diverse than agents such as bacillus an ... | 2005 | 15954721 |
| spectroscopic and computational studies of the atp:corrinoid adenosyltransferase (coba) from salmonella enterica: insights into the mechanism of adenosylcobalamin biosynthesis. | coba from salmonella enterica is a member of an enzymatic system responsible for the de novo biosynthesis of adenosylcobalamin (adocbl), catalyzing the formation of the essential co-c bond by transferring the adenosyl group from a molecule of atp to a transient co(1+)corrinoid species generated in the enzyme active site. a particularly fascinating aspect of this reaction is that the flavodoxin in vivo reducing agent that serves as the electron donor to coba possesses a reduction potential that i ... | 2005 | 15954777 |
| fluoroquinolone treatment of experimental salmonella enterica serovar typhimurium dt104 infections in chickens selects for both gyra mutations and changes in efflux pump gene expression. | to determine the efficacy of enrofloxacin (baytril) in chickens in eradicating three different resistance phenotypes of salmonella enterica and to examine the resistance mechanisms of resulting mutants. | 2005 | 15956100 |