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equivalence of quality control strains of microorganisms used in the compendial microbiological tests: are national culture collection strains identical?the pharmacopoeias list a number of microorganisms to be used in the compendial microbiological tests for confirming the growth-promoting, indicative, and inhibitory properties of the media and demonstrating the suitability of the test for a specific test article. major national culture collections are specified as the sources for these test strains based on their history of deposition and maintenance and use in the compendial tests. using these microorganisms, it has long been assumed that thes ...201021502014
glycoprotein 2 (gp2): grabbing the fimh bacteria into m cells for mucosal immunity.membranous (m) cells are specialized epithelial antigen-transporting cells scattered in the follicle-associated epithelium covering the gut lymphoid follicles such as peyer's patches. although the importance of m cells as a main portal for luminal antigens has long been recognized, molecular mechanisms for m-cell antigen uptake has remained largely elusive. we have recently found that glycoprotein 2 (gp2) is exclusively expressed on m cells among intestinal epithelial cells and serves as an upta ...201021468225
prevalence of salmonella spp. antibodies to toxoplasma gondii, and newcastle disease virus in feral pigeons (columba livia) in the city of jaboticabal, brazil.the rock pigeon (columba livia) may serve as a reservoir for several pathogenic agents that can be transmitted to poultry, wildlife, domesticated pets, and/or humans via excreta, secretions, or dust from feathers. in addition, ingestion of infected pigeons by wild and domestic animals can also transmit these pathogenic agents. the health status of 126 free-living pigeons in an urban area was evaluated by microbiologic culture for salmonella and serologic testing for the presence of antibodies fo ...201021370639
enterobacteriaceae associated with eggs of podocnemis expansa and podocnemis unifilis (testudines:chelonia) in nonpolluted sites of national park of araguaia plains, brazil.fertile eggs of podocnemis expansa and podocnemis unifilis were investigated for the presence of enterobacteria, as these two endangered species have the potential for conservation measures that include egg transfer. knowledge of normal microflora associated with turtles and turtle eggs would help effectively manage the transfer of these eggs among institutions. thirty eggs of each species were collected, aseptically transferred, cracked inside plastic bags containing tetrathionate broth, and sp ...201021370647
ultrasonographic diagnosis of an endocarditis valvularis in a burmese python (python molurus bivittatus) with pneumonia.an 11-yr-old burmese python (python molurus bivittatus) was presented with a history of respiratory symptoms. computed tomography and an endoscopic examination of the left lung were performed and revealed severe pneumonia. microbiologic examination of a tracheal wash sample and an endoscopy-guided sample from the lung confirmed infection with salmonella enterica ssp. iv, enterobacter cloacae, and klebsiella pneumoniae. computed tomographic examination demonstrated a hyperattenuated structure wit ...201021370657
macrophage apoptosis associated with salmonella enterica serovar typhi plasmid.the present study was undertaken to investigate the relationship between plasmid isolated from s. enterica serovar typhi (pr(st98)) and macrophage apoptosis. pr(st98) was transferred into an attenuated s. enterica serovar typhimurium strain ria to create a transconjugant prst98/ria. standard s. enterica serovar typhimurium virulence strain sr-11 was used as a positive control, and ria as a negative one. murine macrophage-like cell line (j774a.1) was used as an infectious cell model in vitro. in ...201021341534
targeting tumors with salmonella typhimurium- potential for therapy.when one considers the organism salmonella enterica serotype typhimurium (s. typhimurium), one usually thinks of the gram-negative enteric pathogen that causes the severe food borne illness, gastroentertitis. in this context, the idea of salmonella being exploited as a cancer therapeutic seems pretty remote. however, there has been an escalating interest in the development of tumor-therapeutic bacteria for use in the treatment of a variety of cancers. this strategy takes advantage of the remarka ...201021321381
a multiple typing approach is recommended for the laboratory-based surveillance of salmonellosis in romania.in romania, salmonella enterica serovar typhimurium isolates are currently typed by antimicrobial resistance profiles and phage typing, as part of the national laboratory-based surveillance system of human enteric infections. the aim of the present study was to assess the added value of complementing this approach with molecular fingerprinting, namely pulsed-field gel electrophoresis (pfge) and multiple-locus variable-number tandem-repeats analysis (mlva). thirty-six s. typhimurium isolates rece ...201021462834
antimicrobial activity of plant essential oils against bacterial and fungal species involved in food poisoning and/or food decay.the currative properties of aromatic and medicinal plants have been recognized since ancient times and, more recently, the antimicrobial activity of plant essential oils has been used in several applications, including food preservation. the purpose of this study was to create directly comparable, quantitative data on the antimicrobial activity of some plant essential oils prepared in the national institute of research-development for chemistry and petrochemistry, bucharest to be used for the fu ...201021462837
pulsed field gel electrophoresis (pfge) analysis for multidrug resistant salmonella enterica serovar schwarzengrund isolates collected in six years (2000-2005) from retail chicken meat in taiwan.salmonella schwarzengrund is one of the causative agents of human salmonellosis and animal infections. high prevalence of multidrug resistant strains of s. schwarzengrund from chicken meat has been recently reported in taiwan. with an attempt to see if such prevalence in chicken meat was due to the recirculation of s. schwarzengrund strains in traditional marketplaces, a total of 173 s. schwarzengrund strains isolated between 2000 and 2005 from 417 retail chicken meat samples purchased from taip ...201021356444
development and evaluation of dna and rna real-time assays for food analysis using the hila gene of salmonella enterica subspecies enterica.the objective of this study was the development of dna and rna real-time pcr methods for detection of food-borne salmonella sp. as rapid alternatives to the traditional cultural method (iso 6579, 2004) in fresh meat carcasses and processed meat samples. these pcr methods were based on the hila sequence, with primers and hybridisation probes designed against this gene target. the primers and probes were evaluated for their efficiency and dynamic range and subsequently the specificity of the assay ...201021356450
minimal effects of high-pressure treatment on salmonella enterica serovar typhimurium inoculated into peanut butter and peanut products.about 1.2 billion pounds of peanut butter are consumed annually in the united states. in 2008 to 2009, an outbreak involving salmonella typhimurium in peanut butter led to a recall of over 3900 products by over 200 companies. more than 700 people became sick, 100 were hospitalized, and 9 people died from this outbreak. this study examines the efficacy of high-pressure processing (hpp) to decrease s. typhimurium american type culture collection (atcc) 53647 inoculated into peanut butter and model ...201021535491
evaluation of antibacterial activity of 3-butenyl, 4-pentenyl, 2-phenylethyl, and benzyl isothiocyanate in brassica vegetables.this study investigated antibacterial activities of 4 isothiocyanates (3-butenyl, 4-phentenyl, 2-phenylethyl, and benzyl isothiocyanate) against 4 gram-positive bacteria (bacillus cereus, bacillus subtilis, listeria monocytogenes, and staphylococcus aureus) and 7 gram-negative bacteria (aeromonas hydrophila, pseudomonas aeruginosa, salmonella choleaesuis, salmonella enterica, serratia marcescens, shigella sonnei, and vibrio parahaemolyticus) by an agar disc diffusion assay. benzyl isothiocyanate ...201021535549
recovery of salmonella enterica serovars typhimurium and tennessee in peanut butter after electron beam exposure.the effect of electron beam (e-beam) radiation on the recovery of salmonella serotypes tennessee (atcc 10722) and typhimurium (atcc 14028) in creamy peanut butter over a 14-d storage period at 22 °c was studied. each salmonella type was independently inoculated into peanut butter and subjected to e-beam doses that ranged from 0 to 3.1 kgy, confirmed by film dosimetry. after 2-, 4-, 6-, 8-, and 14-d of storage, microbial analyses were conducted. survivors were recovered on growth and selective me ...201021535557
reemergence of chloramphenicol in typhoid fever in the era of antibiotic resistance. 201021568009
anti-inflammatory properties of probiotic bacteria on salmonella-induced il-8 synthesis in enterocyte-like caco-2 cells.invasion of the gut by pathogenic salmonella leads to production of il-8 that initiates inflammatory reactions to combat the bacterium. however, its persistent production causes tissue damage and interventions that suppress il-8 production prevent tissue damage. we hypothesised that probiotics could mediate their benefits via inhibition of il-8 synthesis. caco-2 cells were infected with probiotic bifidobacterium infantis w52, lactobacillus casei w56, lactococcus lactis w58, lactobacillus acidoph ...201021840800
protective effect by bacillus smithii tbmi12 spores of salmonella serotype enteritidis in mice.avoiding food-borne diseases by competitive exclusion agents is a proactive strategy. in the current paper, we report the use of bacillus smithii tbmi12 spores as potential competitive exclusion agents. one group of mice was predosed for three successive days with 10(8) colony forming units of b. smithii tbmi12 spores followed by inoculation with 10(6) colony forming units of wild-type salmonella enterica serotype enteritidis cells. microbial plate counts of the animals' livers and spleens showe ...201021840796
molecular typing and antimicrobial resistance of salmonella enterica subspecies enterica serovar choleraesuis isolates from diseased pigs in japan.salmonella enterica serovar choleraesuis (s. choleraesuis) isolates derived from diseased pigs in japan during 2001 and 2005 were analyzed for biotype, based on h(2)s production and dulcitol fermentation, pulsed-field gel electrophoresis (pfge) profile, and antimicrobial resistance profile. s. choleraesuis biotype choleraesuis (biotype choleraesuis) was classified into one genotype, while varietas kunzendorf (var. kunzendorf) was classified into two genotypes. the isolates of var. kunzendorf bel ...201018809209
salmonella infection of a penile prosthesis.patients with erectile dysfunction (ed) who have failed oral or intracavernosal erectogenic therapy may benefit from inflatable penile prosthesis (ipp) placement. such individuals commonly include patients with diabetes mellitus or chronic renal insufficiency. complications of ipp placement include erosion and infection. most often, infection of ipps involves skin flora that are hypothesized to be introduced at the time of device placement and persist as a biofilm, causing clinical infection as ...200918823319
salmonella indiana as a cause of abortion in ewes: genetic diversity and resistance patterns.salmonella enterica subspecies enterica indiana, a food-borne serovar uncommon in most countries, was responsible for an outbreak of abortion in a flock of lacaune dairy ewes in southern spain. drinking water and feedstuff samples were analysed in an attempt to determine the source of the infection. pigeons (columba livia) and turtledoves (streptopelia turtur) in close contact with the ewes were captured and examined for the bacterium. seventeen s. indiana strains were isolated from the ewes and ...200918823722
salmonella infections in antarctic fauna and island populations of wildlife exposed to human activities in coastal areas of australia.salmonella infections in antarctic wildlife were first reported in 1970 and in a search for evidence linking isolations with exposure to human activities, a comparison was made of serovars reported from marine fauna in the antarctic region from 1982-2004 with those from marine mammals in the northern hemisphere. this revealed that 10 (83%) salmonella enterica serovars isolated from antarctic penguins and seals were classifiable in high-frequency (hf) quotients for serovars prevalent in humans an ...200918789175
distribution of integrons and sgi1 among antibiotic-resistant salmonella enterica isolates of animal origin.in salmonella enterica, resistance to antibiotics can be caused by the presence of sgi1, transposons or conjugative plasmids. in this study we were interested in the relative contribution of these genetic elements to the antibiotic resistance of s. enterica isolates collected within a single year in the czech republic from animal sources. altogether 123 antibiotic-resistant isolates belonging to 16 different s. enterica serovars were classified into 3 groups according to the presence of sgi1 and ...200918723300
multiple-locus variable-number tandem repeat analysis for subtyping of salmonella enterica subsp. enterica serovar enteritidis.salmonella enterica subsp. enterica serovar enteritidis is a major food-borne pathogen that caused most of salmonella infections worldwide. s. enteritidis phage type 4 (pt4) especially presents a real challenge for the classical typing methods. we developed a simple multiple-locus variable-number tandem repeat analysis (mlva) assay based on three hypervariable variable-number tandem repeat (vntr) loci for subtyping of salmonella enteritidis. testing an arbitrary chosen strain collection of 110 s ...200918706857
improvement of the live vaccine strain salmonella enterica serovar typhi ty21a for antigen delivery via the hemolysin secretion system of escherichia coli.the attenuated salmonella enterica serovar typhi strain ty21a (ty21a) is the only attenuated live oral vaccine against typhoid fever. ty21a is also an attractive carrier for the delivery of heterologous antigens. we have used ty21a for antigen delivery via the hemolysin (hlya) secretion system of escherichia coli, the prototype of the type i secretion system (t1ss). in this study, we identified by genetic complementation that the specific mutation of rpos correlated with the hemolysin production ...200918706861
non-typhoidal salmonella septic arthritis in an immunocompetent child with a pharyngeal streptococcal infection.we report the case of an immunocompetent child who showed monoarticular arthritis and fever, preceded by pharyngitis and arthralgias. because group a beta-hemolytic streptococcus had been detected in the pharyngeal swab, erythromycin was given on admission. however, based on ultrasound examination, therapy with ceftriaxone and joint fluid drainage were promptly performed, and a rapid and full recovery followed. meanwhile, salmonella enterica infection was revealed in blood and joint fluid. our c ...200918707909
clya cytolysin from salmonella: distribution within the genus, regulation of expression by slya, and pore-forming characteristics.functional homologs of the escherichia coli cytolysin a (clya, hlye, shea) gene have recently been detected in salmonella enterica serovars typhi (s. typhi) and paratyphi a (s. paratyphi a). in this study, analysis of a collection of salmonella strains showed that all s. typhi and s. paratyphi a strains tested harbor an intact copy of the corresponding clya variant, i.e. clya(sty) and clya(spaa), respectively. on the other hand, clya proved to be absent in the s. enterica serovar paratyphi b and ...200918715828
the in vitro anti-pathogenic activity of immunoglobulin concentrates extracted from ovine blood.an immunoglobulin-rich fraction has been prepared from ovine blood in our laboratory. we have investigated its antibacterial activity and binding activity to pathogenic whole cell antigens, lipopolysaccharide (lps) and staphylococcal enterotoxin b. ovine immunoglobulin concentrate (oic) comprised about 73 +/- 2% of igg and 11 +/- 1% of igm on a protein basis. it inhibited the growth of all 13 strains of pathogens tested, but the inhibitory activity varied according to bacterial strain. the inhib ...200918769875
the use of maplt and mlva analyses of phenotypically closely related isolates of salmonella enterica serovar typhimurium.the resolving power of multiple-locus variable-number tandem repeat analysis (mlva) was undertaken on 78 phenotypically closely related isolates of salmonella enterica serovar typhimurium that were previously analysed with multiple amplification of phage locus typing (maplt) and pulsed-field gel electrophoresis (pfge). isolates were tested with 10 primer sets targeting tandem repeat loci in the s. typhimurium genome. a new primer set targeting the sb21(st64b) locus was also assessed for maplt an ...200918617439
disease threats to the endangered iberian lynx (lynx pardinus).the iberian lynx, (lynx pardinus), is the most endangered felid in the world. to determine whether sympatric carnivores are reservoirs of pathogens posing a disease risk for the lynx, evidence of exposure to 17 viral, bacterial and protozoan agents was investigated in 176 carnivores comprising 26 free-living lynx, 53 domestic cats, 28 dogs, 33 red foxes (vulpes vulpes), 24 egyptian mongooses (herpestes ichneumon), 10 common genets (genetta genetta) and 2 eurasian badgers (meles meles) in the are ...200918555712
mitracarpus frigidus aerial parts exhibited potent antimicrobial, antileishmanial, and antioxidant effects.the crude extract and the hexane, ch(2)cl(2), etoac, n-buoh, and hydromethanolic fractions of the aerial parts of mitracarpus frigidus were evaluated against promastigote forms of two species of leishmania (l. chagasi and l. amazonensis), 11 strains of bacteria (staphylococcus aureus, pseudomonas aeruginosa, salmonella enterica sorovar tythimurium, shigella sonnei, klebsiella pneumoniae, escherichia coli, micrococcus luteus, enterococcus faecalis, enterobacter cloacae, streptococcus pyogenes and ...200918644325
molecular analysis of high-level ciprofloxacin resistance in salmonella enterica serovar typhi and s. paratyphi a: need to expand the qrdr region?fourteen strains of s. typhi (n=13) and s. paratyphi a (n=1) resistant to ciprofloxacin were compared with 30 ciprofloxacin decreased-susceptibility strains on the basis of qnr plasmid analysis, and nucleotide substitutions at gyra, gyrb, parc and pare. in ciprofloxacin-resistant strains, five s. typhi and a single s. paratyphi a showed triple mutations in gyra (ser83-->phe, asp87-->asn, glu133-->gly) and a novel mutation outside the quinolone resistance determining region (qrdr) (met52-->leu). ...200918687156
multiplex pcr for differential diagnosis of emerging typhoidal pathogens directly from blood samples.classically salmonella enterica serovar typhi (s. typhi) is associated with typhoid, a major health problem in developing countries. however, in recent years s. paratyphi a and vi-negative variants of s. typhi have emerged rapidly. we have developed a nested multiplex pcr targeting five different genes for differential diagnosis of typhoidal pathogens which has been optimized to be directly applicable on clinical blood samples. of 42 multiplex pcr-positive blood samples, 26, nine, and two were v ...200918413005
survival of selected pathogens in diluted sludge of a thermophilic waste treatment plant and in nacl-solution under aerobic and anaerobic conditions.decimal reduction times (drt or d-value) of campylobacter jejuni, salmonella enterica (formerly salmonella choleraesuis) serovar senftenberg, escherichia coli, and listeria monocytogenes were determined in two different matrices, diluted fermenter sludge (dfs) and 0.95% nacl-solution (nacl) at 50 degrees c, both under aerobic and anaerobic conditions. depending on aeration, matrix composition, and the respective organism, the d-values varied between 10min and more than 15h. generally the viabili ...200918445518
acid pre-adaptation enhances virulence of salmonella enterica serovar typhimurium dam mutant.it is well established that success or failure of bacterial pathogens during infection relies upon its ability to overcome many lethal environments in the host such as acidity, osmolarity and bile salts. in the present study, we have studied the effects of acid adaptation on the virulence of salmonella enterica serovar typhimurium dam mutant. our results indicated that ld(50) of adapted strains were lower than those of control strains. also, the in vivo assays have shown that the development of ...200918456425
surveillance of antimicrobial resistance of salmonella enterica serotype typhi in seven asian countries.two hundred and four salmonella enterica serotype typhi (s. typhi) isolates were collected from seven asian countries during 2002-2004. multidrug-resistant s. typhi (resistant to > or = 3 antibiotics) was detected in 84 (41.2%) isolates and 142 (69.6%) showed reduced susceptibility to ciprofloxacin (minimum inhibitory concentration=0.125-1.0 mg/l). this study highlights the worsening situation of antimicrobial resistance of s. typhi in asia.200918474127
a multi-state outbreak of salmonella saintpaul in australia associated with cantaloupe consumption.a multi-state outbreak of salmonella enterica serovar saintpaul infection occurred in australia during october 2006. a case-control study conducted in three affected jurisdictions, new south wales, victoria and australian capital territory, included 36 cases with the outbreak-specific strain of s. saintpaul identified by multiple locus variable-number tandem repeat analysis (mlva) in a faecal specimen and 106 controls. consumption of cantaloupe (rockmelon) was strongly associated with illness (a ...200918559128
modulation of macrophage proinflammatory functions by cytokine-expressing salmonella vectors.we previously reported that the intraperitoneal administration of recombinant strains of salmonella enterica serovar typhimurium, engineered to express murine il-2 (designated gidil2) or ifn-gamma (gidifngamma), induced a cytokine-specific modulation of the host innate immune response. interestingly, the bacteria-expressed cytokines were not secreted, but instead were associated with the bacterial cytosol. to understand the mechanism by which these two transfectants influence immune cells, we in ...200918835224
predicting salmonella enterica serotypes by repetitive sequence-based pcr.repetitive extragenic palindromic sequence-based pcr (rep-pcr) utilizing a semi-automated system, was evaluated as a method to determine salmonella serotypes. a group of 216 salmonella isolates belonging to 13 frequently isolated serotypes and one rarer serotype from poultry were used to create a dna fingerprint library with the diversilab system software. subsequently, a blinded set of 44 poultry isolates were fingerprinted and queried against the library in an attempt to putatively assign a se ...200918835303
fluorescent bio-barcode dna assay for the detection of salmonella enterica serovar enteritidis.salmonella enterica serovar enteritidis is one of the most frequently reported causes of foodborne illness. it is a major threat to the food safety chain and public health. a highly amplified bio-barcode dna assay for the rapid detection of the insertion element (iel) gene of salmonella enteritidis is reported in this paper. the biosensor transducer is composed of two nanoparticles: gold nanoparticles (au-nps) and magnetic nanoparticles (mnps). the au-nps are coated with the target-specific dna ...200918835708
potent anti-tumor activity of systemically-administered il2-expressing salmonella correlates with decreased angiogenesis and enhanced tumor apoptosis.salmonella enterica serovar typhimurium (hereafter s. typhimurium) stains have been shown to exert a potent inhibitory effect on the growth of human and mouse tumors in experimental models. our laboratory has previously demonstrated that an attenuated strain of s. typhimurium engineered to express il2 (designated strain gidil2) has demonstrable immunopotentiating properties, particularly affecting the innate arm of the immune system. in the present study, we wished to explore the properties of i ...200918849195
interaction of salmonella enterica with basil and other salad leaves.contaminated salad leaves have emerged as important vehicles for the transmission of enteric pathogens to humans. a recent outbreak of salmonella enterica serovar senftenberg (s. senftenberg) in the united kingdom has been traced to the consumption of contaminated basil. using the outbreak strain of s. senftenberg, we found that it binds to basil, lettuce, rocket and spinach leaves showing a pattern of diffuse adhesion. flagella were seen linking s. senftenberg to the leaf epidermis, and the del ...200918830276
reduction in infection risk through treatment of microbially contaminated surfaces with a novel, portable, saturated steam vapor disinfection system.surface-mediated infectious disease transmission is a major concern in various settings, including schools, hospitals, and food-processing facilities. chemical disinfectants are frequently used to reduce contamination, but many pose significant risks to humans, surfaces, and the environment, and all must be properly applied in strict accordance with label instructions to be effective. this study set out to determine the capability of a novel chemical-free, saturated steam vapor disinfection syst ...200918834748
early immune response following salmonella enterica subspecies enterica serovar typhimurium infection in porcine jejunal gut loops.salmonella enterica subspecies enterica serovar typhimurium, commonly called s. typhimurium, can cause intestinal infections in humans and various animal species such as swine. to analyze the host response to salmonella infection in the pig we used an in vivo gut loop model, which allows the analysis of multiple immune responses within the same animal. four jejunal gut-loops were each inoculated with 3 x 10(8) cfu of s. typhimurium in 3 one-month-old piglets and mrna expressions of various cytok ...200918922229
abelson tyrosine kinase facilitates salmonella enterica serovar typhimurium entry into epithelial cells.the intracellular gram-negative bacterial pathogen salmonella enterica serovar typhimurium gains entry into nonphagocytic cells by manipulating the assembly of the host actin cytoskeleton. s. enterica serovar typhimurium entry requires a functional type iii secretion system, a conduit through which bacterial effector proteins are directly translocated into the host cytosol. we and others have previously reported the enhancement of tyrosine kinase activities during salmonella serovar typhimurium ...200918936177
human polymorphonuclear neutrophil responses to burkholderia pseudomallei in healthy and diabetic subjects.the major predisposing factor for melioidosis is diabetes mellitus, but no immunological mechanisms have been investigated to explain this. in this study, polymorphonuclear neutrophil (pmn) responses to burkholderia pseudomallei, the causative agent of melioidosis, in healthy and diabetic thai subjects were determined by flow cytometry. the results showed that b. pseudomallei displayed reduced uptake by pmns compared to salmonella enterica serovar typhimurium and escherichia coli. additionally, ...200918955471
interleukin-23 orchestrates mucosal responses to salmonella enterica serotype typhimurium in the intestine.salmonella enterica serotype typhimurium causes an acute inflammatory reaction in the ceca of streptomycin-pretreated mice that involves t-cell-dependent induction of gamma interferon (ifn-gamma), interleukin-22 (il-22), and il-17 expression (genes ifn-gamma, il-22, and il-17, respectively). we investigated here the role of il-23 in initiating these inflammatory responses using the streptomycin-pretreated mouse model. compared to wild-type mice, the expression of il-17 was abrogated, il-22 expre ...200918955477
surveillance of antibiotic resistance evolution and detection of class 1 and 2 integrons in human isolates of multi-resistant salmonella typhimurium obtained in uruguay between 1976 and 2000.to study the evolution of antibiotic resistance in isolates of salmonella enterica subspecies enterica serovar typhimurium (salmonella typhimurium) obtained in uruguay between the years 1976 and 2000, and to determine the incidence of class 1 and 2 integrons in the multi-resistant isolates.200918977678
mutagenesis of region 4 of sigma 28 from chlamydia trachomatis defines determinants for protein-protein and protein-dna interactions.transcription factor sigma(28) in chlamydia trachomatis (sigma(28)(ct)) plays a role in the regulation of genes that are important for late-stage morphological differentiation. in vitro mutational and genetic screening in salmonella enterica serovar typhimurium was performed in order to identify mutants with mutations in region 4 of sigma(28)(ct) that were defective in sigma(28)-specific transcription. specially, the previously undefined but important interactions between sigma(28)(ct) region 4 ...200918978051
effect of transcriptional activators rama and soxs on expression of multidrug efflux pumps acrab and acref in fluoroquinolone-resistant salmonella typhimurium.multidrug resistance (mdr) including fluoroquinolone resistance in salmonella typhimurium can result from overexpression of efflux pumps. we examined the mechanisms of fluoroquinolone resistance among in vitro-induced ciprofloxacin-resistant salmonella typhimurium mutants, ltl and lth, derived from laboratory strain lt2.200918984645
characterization of salmonella enterica isolates from infants and toddlers in wuhan, china.extended-spectrum cephalosporins and fluoroquinolones are important antimicrobials for treating invasive salmonellosis, and emerging resistance to these antimicrobials is of paramount concern. this study reports on the antimicrobial susceptibility and molecular characterization of salmonella enterica isolates recovered in 2006 from 0- to 3-year-old outpatients in china.200918984647
porcine in vitro and in vivo models to assess the virulence of salmonella enterica serovar typhimurium for pigs.salmonella typhimurium infections in pigs pose an important human health hazard. one promising control measure is the development of live attenuated vaccine strains using defined knockout mutants. preferably, screening of candidate knockout vaccine strains for attenuation should first be done in models allowing testing of a large number of strains. thereafter, a limited number of selected strains should be further characterized in an experimental infection model in pigs. the aim of the present s ...200918987064
proteolytic inactivation of tissue factor pathway inhibitor by bacterial omptins.the immune response to infection includes activation of the blood clotting system, leading to extravascular fibrin deposition to limit the spread of invasive microorganisms. some bacteria have evolved mechanisms to counteract this host response. pla, a member of the omptin family of gram-negative bacterial proteases, promotes the invasiveness of the plague bacterium, yersinia pestis, by activating plasminogen to plasmin to digest fibrin. we now show that the endogenous anticoagulant tissue facto ...200918988866
multiple abscesses caused by salmonella enterica and corynebacterium pseudotuberculosis in a dromedary camel.a rare case of arthritis, peri-arthiritis and pleurits associated with salmonella enterica and corynebacterium pseudotuberculosis infection in a dromedary camel is reported. articular infections caused by non-typhoidal salmonella have been exceptionally described in human medicine. to our knowledge, this would be the first description of articular infections associated with non-thyphoidal salmonella in other mammals than humans. possible pathogenesis of the infection is discussed.200918989744
fatal community-acquired pneumonia caused by legionella pneumophila and fluoroquinolone-resistant salmonella enterica serotype choleraesuis bacteraemia. 200918993035
correlating blood immune parameters and a cct7 genetic variant with the shedding of salmonella enterica serovar typhimurium in swine.the porcine response to salmonella infection is critical for control of salmonella fecal shedding and the establishment of salmonella carrier status. in this study, 40 crossbred pigs were intranasally inoculated with salmonella enterica serovar typhimurium (salmonella typhimurium) and monitored for salmonella fecal shedding and blood immune parameters at 2, 7, 14 and 20 days post-inoculation (dpi). using a multivariate permutation test, a positive correlation was observed between salmonella typh ...200918996651
occurrence and characterization of salmonella enterica subspecies enterica serovar 9,12:l,v:- strains from bulgaria, denmark, and the united states.in 2006, salmonella enterica serovar i 9,12:l,v:- emerged in bulgaria. the aim of this study was to characterize salmonella serovar i 9,12:l,v:- isolates from bulgaria, denmark, and the united states. we compared isolates of salmonella i 9,12:l,v:- and diphasic serovars with similar antigenic formulas by pulsed-field gel electrophoresis (pfge) and antimicrobial susceptibility. the phase 2 flagellin gene (fljb) was also sequenced for selected isolates. by pfge, the salmonella i 9,12:l,v:- isolate ...200918998175
the potassium transporter trk and external potassium modulate salmonella enterica protein secretion and virulence.potassium (k(+)) is the most abundant intracellular cation and is essential for many physiological functions of all living organisms; however, its role in the pathogenesis of human pathogens is not well understood. in this study, we characterized the functions of the bacterial trk k(+) transport system and external k(+) in the pathogenesis of salmonella enterica, a major food-borne bacterial pathogen. here we report that trk is important for salmonella to invade and grow inside epithelial cells. ...200919001074
characterization of plasmids harbouring qnrs1, qnrb2 and qnrb19 genes in salmonella.the aim of this study was to identify and characterize plasmids carrying qnrs1, qnrb2 and qnrb19 genes identified in salmonella strains from the netherlands. the identification of plasmids may help to follow the dissemination of these resistance genes in different countries and environments.200919001452
differential mrna expression of the avian-specific toll-like receptor 15 between heterophils from salmonella-susceptible and -resistant chickens.pattern recognition receptors (prrs) are essential for recognition of conserved molecular constituents found on infectious microbes. toll-like receptors (tlrs) are a critical component of the prr repertoire and are coupled to downstream production of cytokines, chemokines, and antimicrobial peptides by tlr adaptor proteins. our laboratory previously demonstrated a role for tlr function in the differential innate response of two lines of chickens to bacterial infections. the aim of the present st ...200919002681
functional analysis of a large non-conserved region of flgk (hap1) from rhodobacter sphaeroides.the single subpolar flagellum of rhodobacter sphaeroides shows an enlarged hook-filament junction. one of the two proteins that compose this section of the filament is hap1(rs) (flgk(rs)) it contains a central non-conserved region of 860 amino acids that makes this protein about three times larger than its homologue in salmonella enterica serovar typhimurium. we investigated the role of this central portion of the unusually large hap1 protein of r. sphaeroides by monitoring the effects of serial ...200919003427
salmonella induces death of cd8alpha(+) dendritic cells but not cd11c(int)cd11b(+) inflammatory cells in vivo via myd88 and tnfr1.dendritic cells (dcs), whose lifespan influences their ability to stimulate the immune system, are potent apcs that are critical for initiating immunity. here, we show that oral infection with salmonella enterica serovar typhimurium induces death of dcs in the gut-draining lymph nodes. although cd8alpha(+) dcs were sensitive to salmonella-induced death, cd8alpha(-) dcs and in particular recruited cd11c(int)cd11b(+) inflammatory cells, were resistant. infecting mice deficient for myd88 revealed t ...200919004989
influence of promoter, gene copy number, and preexisting immunity on humoral and cellular responses to a vectored antigen delivered by a salmonella enterica vaccine.attenuated salmonella strains are currently in production as vaccines for protection of animals against salmonellosis. such commercial strains offer the potential to deliver heterologous antigen to protect animals against other diseases. one vaccine strain, attenuated salmonella enterica serovar typhimurium (stm-1), was tested for the ability to deliver ovalbumin and to induce immune responses in mice. two vaccine trials were performed testing the influence of promoter choice, the location of th ...200919005022
controlled evaluation of bactec peds plus/f and bactec lytic/10 anaerobic/f media for isolation of salmonella enterica serovars typhi and paratyphi a from blood.we compared anaerobic lytic (al) and pediatric aerobic resin-containing (peds plus/f) blood culture media for the isolation of salmonella enterica serotype typhi or paratyphi a from children. the yields from al and peds plus/f media were the same with equal volumes of blood, but recovery was faster from al medium than peds plus/f medium (10.7 and 16.4 h, respectively) (p < 0.001).200919005140
ciprofloxacin-resistant salmonella enterica serovar typhi from kuwait with novel mutations in gyra and parc genes.blood isolates of salmonella enterica serovar typhi from two recently returned bangladeshi patients in kuwait were ciprofloxacin resistant, with ciprofloxacin mics of 12 mg/liter for both isolates. both isolates had three novel gyra mutations (55-leu-->trp, 87-asp-->ala, and 106-gln-->arg) and three novel parc mutations (84-glu-->lys, 106-trp-->gly, and 128-tyr-->asp).200918971360
characterization of the myo-inositol utilization island of salmonella enterica serovar typhimurium.knockout mutation of stm4432 resulted in a growth-deficient phenotype of salmonella enterica serovar typhimurium in the presence of myo-inositol (mi) as the sole carbon source. stm4432 is part of a 22.6-kb genomic island which spans stm4417 to stm4436 (genomic island 4417/4436) and is responsible for mi degradation. genome comparison revealed the presence of this island in only six salmonella strains and a high variability of the iol gene organization in gram-negative bacteria. upon nonpolar del ...200919011032
characterisation of antimicrobial resistance-associated integrons and mismatch repair gene mutations in salmonella serotypes.in this study, we examined the presence of integrons and salmonella genomic island 1 (sgi1) and assessed their contribution to antimicrobial resistance as well as determining the extent of the mutator phenotype in salmonella isolates. a total of 81 salmonella enterica serotype typhimurium isolates were examined for the presence of integrons and sgi1 and for hypermutators using polymerase chain reaction (pcr) and the mutator assay, respectively. an additional 336 salmonella isolates were also use ...200919013057
interleukin-15 and nk1.1+ cells provide innate protection against acute salmonella enterica serovar typhimurium infection in the gut and in systemic tissues.control of bacterial colonization at mucosal surfaces depends on rapid activation of the innate immune system. interleukin-15 (il-15) directs the development, maturation, and function of a population of cells positive for nk1.1, such as natural killer (nk) cells, which are critical components of the innate immune defense against several viral and bacterial pathogens. using il-15-deficient mice, in vivo depletion of nk1.1(+) cells from wild-type mice, and in vivo overexpression of il-15 from a re ...200919015253
truncated tni module adjacent to the complex integron of salmonella genomic island 1 in salmonella enterica serovar virchow.salmonella genomic island 1 was identified for the first time in salmonella enterica serovar virchow isolated from humans in taiwan. the complex class 1 integron conferring multidrug resistance was shown to be inserted within open reading frame (orf) s023 and contains for the first time a partial transpositional module. the 5-bp target duplication flanking the complex integron suggests that its insertion in orf s023 was by transposition.200919015337
a small-molecule screen identifies the antipsychotic drug pimozide as an inhibitor of listeria monocytogenes infection.we developed a screening procedure to identify small-molecule compounds that altered infection by listeria monocytogenes to gain insights into bacterial/host cellular processes required for intracellular pathogenesis. a small-molecule library of 480 compounds with known biological functions was screened, and 21 compounds that altered the l. monocytogenes infection of murine bone marrow-derived macrophages (bmm) were identified. the identified compounds affected various cellular functions, such a ...200919015342
variation in salmonella enterica serovar typhi inchi1 plasmids during the global spread of resistant typhoid fever.a global collection of plasmids of the inchi1 incompatibility group from salmonella enterica serovar typhi were analyzed by using a combination of dna sequencing, dna sequence analysis, pcr, and microarrays. the inchi1 resistance plasmids of serovar typhi display a backbone of conserved gene content and arrangement, within which are embedded preferred acquisition sites for horizontal dna transfer events. the variable regions appear to be preferred acquisition sites for dna, most likely through c ...200919015365
nramp1 drives an accelerated inflammatory response during salmonella-induced colitis in mice.a recently developed model for enterocolitis in mice involves pre-treatment with the antibiotic streptomycin prior to infection with salmonella enterica serovar typhimurium (s. typhimurium). the contribution of nramp1/slc11a1 protein, a critical host defence mechanism against s. typhimurium, to the development of inflammation in this model has not been studied. here, we analysed the impact of nramp1 expression on the early development of colitis using isogenic nramp1(+/+) and nramp1(-/-) mice. w ...200919016783
mechanisms of rnd multidrug efflux pumps.rnd (resistance-nodulation-division) family transporters are widespread especially among gram-negative bacteria, and catalyze the active efflux of many antibiotics and chemotherapeutic agents. they have very large periplasmic domains, and form tripartite complexes with outer membrane channels and periplasmic adaptor proteins. acrab-tolc complex of escherichia coli, which pumps out a very wide range of drugs, has been studied most intensively. early studies showed that the transporter captures ev ...200919026770
effect of sample preparation and bacterial concentration on salmonella enterica detection in poultry meat using culture methods and pcr assaying of preenrichment broths.we evaluated the sensitivity of a pcr assay in the detection of salmonella enterica at the broth preenrichment step of poultry meat. a total of 162 retail poultry meat samples, which were prepared by manual massaging, stomacher or no homogenization were compared for salmonella recovery. using these homogenization methods, the pcr assay at the broth preenrichment step detected salmonella in, respectively, 48.9%, 62.2% and 50.0% of meat and giblet samples detected as salmonella-positive using the ...200919028296
interaction of enteric bacterial pathogens with murine embryonic stem cells.embryonic stem (es) cells are susceptible to genetic manipulation and retain the potential to differentiate into diverse cell types, which are factors that make them potentially attractive cells for studying host-pathogen interactions. murine es cells were found to be susceptible to invasion by salmonella enterica serovar typhimurium and shigella flexneri and to the formation of attaching and effacing lesions by enteropathogenic escherichia coli. s. enterica serovar typhimurium and s. flexneri c ...200919029302
qnrd, a novel gene conferring transferable quinolone resistance in salmonella enterica serovar kentucky and bovismorbificans strains of human origin.in a previous study, four salmonella isolates from humans in the henan province of china showed reduced susceptibility to ciprofloxacin (mic, 0.125 to 0.25 microg/ml) but were susceptible to nalidixic acid (mic, 4 to 8 microg/ml). all isolates were negative for known qnr genes (a, b, and s), aac(6')ib-cr, and mutations in gyra and parc. plasmid dna was extracted from all four isolates and transformed into escherichia coli tg1 and dh10b cells by electroporation, and transformants were selected on ...200919029321
csra and csrb are required for the post-transcriptional control of the virulence-associated effector protein avra of salmonella enterica.the virulence-associated effector protein avra of salmonella enterica is an ubiquitin-like acetyltransferase/cysteine protease, which interferes with the first line of immune response of the target organism. in contrast to translation of the avra protein in s. enterica strains, which takes place either constitutively (class 1 strains), or after acid induction (class 2 strains), or not at all (class 3 strains); the constitutive transcription of the respective avra genes occurs regardless of these ...200919042154
regulation of salmonella-induced membrane ruffling by sipa differs in strains lacking other effectors.the salmonella pathogenicity island 1 (spi-1) type three secretion system (ttss) is essential for salmonella invasion of host cells through its triggering of actin-dependent membrane ruffles. the spi-1 effectors sipa, sope, sope2 and sopb all have actin regulating activities and contribute to invasion. the precise role of actin regulation by sipa in salmonella invasion remains controversial since divergent data have been presented regarding the relationship between sipa and membrane ruffling. we ...200919046340
the malf p2 loop of the atp-binding cassette transporter malfgk2 from escherichia coli and salmonella enterica serovar typhimurium interacts with maltose binding protein (male) throughout the catalytic cycle.we have investigated the interaction of the uncommonly large periplasmic p2 loop of the malf subunit of the maltose atp-binding cassette transporter (malfgk(2)) from escherichia coli and salmonella enterica serovar typhimurium with maltose binding protein (male) by site-specific chemical cross-linking in the assembled transport complex. we focused on possible distance changes between two pairs of residues of the p2 loop and male during the transport cycle. the distance between malf(s205c) and ma ...200919047355
public health assessment of salmonella enterica serovar enteritidis inactivated-vaccine treatment in layer flocks.although there have been several reports on the efficacy assessment of a salmonella enterica serovar enteritidis vaccine against intestinal and parenchymatous organ diseases of laying hens, no public health risk characterization of its long-term effect on eggs has been reported. in this study, we attempted to assess the public health effect of an inactivated s. enterica serovar enteritidis vaccine against serovar enteritidis contamination of chicken eggs. we analyzed serovar enteritidis isolatio ...200919047380
in ovo treatment with cpg oligodeoxynucleotides decreases colonization of salmonella enteriditis in broiler chickens.induction of the innate immune response in newly hatched chickens is important for limiting infections with bacteria, such as salmonella enterica serovar enteriditis (se). cpg oligodeoxynucleotides (cpg-odn) can stimulate the innate immune response of young chickens. therefore, we examined the effectiveness of cpg-odn administered in ovo on intestinal colonization by se and the ability to modulate the function of heterophils in young chickens. heterophils were isolated from 2-day-old chickens an ...200919019459
salmonella serovar specific upregulation of porcine defensins 1 and 2 in a jejunal epithelial cell line.defensins are important antimicrobial effector peptides of the innate immune system, which provides protection against bacterial infections in the intestine. salmonella choleraesuis and salmonella typhimurium are the most commonly isolated serovars in pig, but disease outcome is dependent on the salmonella serovar. these infections are a serious problem for the swine industry and are also posing a major threat to public health because of salmonella-related food-borne illnesses in human. to under ...200919019577
tlr9-independent effects of inhibitory oligonucleotides on macrophage responses to s. typhimurium.detection of bacterial cpg-containing dna (cpg dna) by innate immune cells is dependent on toll-like receptor 9 (tlr9). here we show that the expression of tlr9 mrna was induced in mouse bone marrow-derived macrophages (bmms) upon infection with the facultative gram-negative intracellular bacterium salmonella enterica serovar typhimurium (s. typhimurium). treatment of bmm with the inhibitory oligonucleotide (odn) 2114, an antagonist of tlr9 signalling, enhanced intracellular s. typhimurium numbe ...200919048019
differential expression from two iron-responsive promoters in salmonella enterica serovar typhimurium reveals the presence of iron in macrophage-phagosomes.the metal status of macrophage-phagosomes during salmonella infection is largely unknown. in this study, we have precisely calibrated the metal-specificities of two metal-responsive promoters, p(irobcde) and p(sodb), from salmonella enterica serovar typhimurium and used these to directly monitor iron-levels in salmonella-containing macrophage-phagosomes. expression from the p(irobcde) promoter is highly elevated in metal-depleted media but low in media supplemented with iron or cobalt, and to a ...200919049822
selection, characterization, and application of dna aptamers for the capture and detection of salmonella enterica serovars.sensitive and specific pre-analytical sample processing methods are needed to enhance our ability to detect and quantify food borne pathogens from complex food and environmental samples. in this study, dna aptamers were selected and evaluated for the capture and detection of salmonella enterica serovar. typhimurium. a total of 66 candidate sequences were enriched against s. typhimurium outer membrane proteins (omps) with counter-selection against escherichia coli omps and lipopolysaccharides (lp ...200919049862
detection of qnr genes in salmonella isolated from humans in denmark. 200919056747
probiotic bacteria are antagonistic to salmonella enterica and campylobacter jejuni and influence host lymphocyte responses in human microbiota-associated immunodeficient and immunocompetent mice.a defined human microbiota-associated (hma) mouse model in balb/c and immunodeficient tgepsilon26 mice was used to assess the ability of probiotic lactobacilli and bifidobacteria to enhance colonization resistance to gastrointestinal (gi) tract pathogens. probiotic bacteria (1x10(8) colony forming unit (cfu)/ml) successfully excluded campylobacter jejuni from both strains of mice 7 days after challenge. the probiotic bacteria also reduced the number of salmonella in the large intestines of both ...200919065588
construction of phage mutants.recent studies have established that the most abundant life form, that of phages, has had major influence on the biosphere, bacterial evolution, bacterial genome, and lateral gene transmission. importantly the phages have served and continue to serve as valuable model systems. such studies have led to a renewed interest and activity in the study of phages and their genomes. in order to determine the details of the involvement of phages in these important processes and activities, it is critical ...200919066824
generalized transduction.transduction is the process in which bacterial dna is transferred from one bacterial cell to another by means of a phage particle. there are two types of transduction, generalized transduction and specialized transduction. in this chapter two of the best-studied systems - escherichia coli-phage p1, and salmonella enterica-phage p22 - are discussed from theoretical and practical perspectives.200919066827
detection of salmonella in finishing pigs on farm and at slaughter in piedmont, italy.salmonella is one of the most common causes of human gastroenteritis often associated with pork consumption. the aims of this cross-sectional study were to collect preliminary data on the presence of salmonella enterica in pigs in piedmont (italy), through sampling on farm and at slaughter and to gather pilot data on serotypes and phagetypes present in the sampled area and distribution of anti-microbial resistance among isolated strains. salmonella was detected through culture and identified wit ...200919068072
the immunobiology of avian systemic salmonellosis.avian systemic salmonellosis is primarily caused by salmonella enterica serovar gallinarum and serovar pullorum causing the diseases fowl typhoid and pullorum disease respectively. during infection interaction with the immune system occurs in three main phases. first is invasion via the gastrointestinal tract. infection with s. pullorum or s. gallinarum does not cause substantial inflammation, unlike s. typhimurium or s. enteritidis. through in vitro models it was found that s. gallinarum does n ...200919070366
oral delivery of dna vaccine encoding vp28 against white spot syndrome virus in crayfish by attenuated salmonella typhimurium.protective immune responses in shrimp induced by dna vaccines against white spot syndrome virus (wssv) with intramuscular injection have been reported in recent reports. in this study, we investigated the utilities of attenuated salmonella enterica serovar typhimurium (salmonella typhimurium) as a bactofection vehicle for the oral delivery of a dna vaccine plasmid to crayfish (cambarus clarkii). the dna vaccine plasmid pcdna3.1-vp28, encoding viral envelope protein vp28, was transformed to an at ...200919071178
outbreak of salmonella enterica serotype montevideo infections in france linked to consumption of cheese made from raw milk.in 2006, an outbreak of salmonella enterica serotype montevideo infections occurred in france. a matched case-control study and microbiological, environmental, and veterinary investigations were conducted to determine the source of this outbreak. a case was defined as a resident of france in whom salmonella montevideo was isolated from a stool or blood specimen between october 16, 2006, and january 6, 2007. patients were interviewed using a standardized questionnaire. salmonella montevideo food ...200919072083
bacterial dna topology and infectious disease.the gram-negative bacterium escherichia coli and its close relative salmonella enterica have made important contributions historically to our understanding of how bacteria control dna supercoiling and of how supercoiling influences gene expression and vice versa. now they are contributing again by providing examples where changes in dna supercoiling affect the expression of virulence traits that are important for infectious disease. available examples encompass both the earliest stages of pathog ...200919073701
molecular characterization and antimicrobial susceptibility of salmonella isolates from infections in humans in henan province, china.we characterized 208 human salmonella isolates from 2006 to 2007 and 27 human salmonella enterica serovar typhimurium isolates from 1987 to 1993 from henan province, china, by serotyping, by antimicrobial susceptibility testing, and, for the most common serovars, by pulsed-field gel electrophoresis (pfge). the most common serovars among the 2006-2007 isolates were s. enterica serovar typhimurium (27%), s. enterica serovar enteritidis (17%), s. enterica serovar derby (10%), s. enterica serovar in ...200919073874
leucine-responsive regulatory protein (lrp) acts as a virulence repressor in salmonella enterica serovar typhimurium.leucine-responsive regulatory protein (lrp) is a global gene regulator that influences expression of a large number of genes including virulence-related genes in escherichia coli and salmonella. no systematic studies examining the regulation of virulence genes by lrp have been reported in salmonella. we report here that constitutive expression of lrp [lrp(con)] dramatically attenuates salmonella virulence while an lrp deletion (deltalrp) mutation enhances virulence. the lrp(con) mutant caused pl ...200919074398
association of is26-composite transposons and complex in4-type integrons generates novel multidrug resistance loci in salmonella genomic island 1.clinical isolates of salmonella enterica serovar haifa and newport, which displayed extended multidrug resistance phenotypes, were investigated for the presence of salmonella genomic island 1 (sgi1) and the genetic organization of its antibiotic resistance gene clusters.200919074421
identification and characterization of class 1 integron resistance gene cassettes among salmonella strains isolated from imported seafood.a total of 210 salmonella isolates, representing 64 different serovars, were isolated from imported seafood samples, and 55/210 isolates were found to be resistant to at least one antibiotic. class 1 integrons from three multidrug-resistant salmonella enterica strains (salmonella enterica serovars newport [strain 62], typhimurium var. copenhagen [strain 629], and lansing [strain 803], originating from hong kong, the philippines, and taiwan, respectively) were characterized. southern hybridizatio ...200919074612
a mixture containing galactooligosaccharide, produced by the enzymic activity of bifidobacterium bifidum, reduces salmonella enterica serovar typhimurium infection in mice.the prebiotic bimuno is a mixture containing galactooligosaccharide, produced by the galactosyltransferase activity of bifidobacterium bifidum ncimb 41171 in the presence of lactose. previous studies have implicated prebiotics in reducing infections by enteric pathogens, thus it was hypothesized that bimuno may confer some protection in the murine host from salmonella enterica serovar typhimurium (s. typhimurium) infection. in this study, infection caused by s. typhimurium sl1344nal(r) in the pr ...200919074651
characterization of bacteriophages used in the salmonella enterica serovar enteritidis phage-typing scheme.the 16 salmonella enterica serovar enteritidis (s. enteritidis) typing phages (setps) used in the laboratory of enteric pathogens (health protection agency, london, uk) phage-typing scheme have not previously been characterized in detail. we have examined the adsorption properties of the phages with respect to a number of s. enterica serovars and defined phage morphology with electron microscopy. pfge was used to estimate overall genome size and banding patterns generated by electrophoresis foll ...200919074657
downregulation of rpon-controlled genes protects salmonella cells from killing by the cationic antimicrobial peptide polymyxin b.salmonella enterica polymyxin b (pm) resistance is modulated mainly by substitutions of the acyl chains and the phosphate groups on the lipid a moiety of lipopolysaccharide. these modifications are mediated by genes under the control of the pmra/pmrb and phop/phoq two-component regulatory systems. in this study, a deletion in the gene encoding the alternative sigma(54) factor, rpon, was shown to increase pm resistance without affecting protamine sensitivity. the results presented here showed tha ...200919076233
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