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interference with the quorum sensing systems of salmonella enterica serovar typhimurium: possibilities and implications. 200718018856
modelling of the regulation of the hila promoter of type three secretion system of salmonella enterica serovar typhimurium.one of the most common modes of secretion of toxins in gram-negative bacteria is via the type three secretion system (ttss), which enables the toxins to be specifically exported into the host cell. the hila gene product is a key regulator of the expression of the ttss located on the pathogenicity island (spi-1) of salmonella enterica serovar typhimurium. it has been proposed earlier that the regulation of hila expression is via a complex feedforward loop involving the transactivators hild, hilc ...200719003447
isolasion, identification and antimicrobial resistance patterns of salmonella from meat products in tehran.the present study was carried out from 400 samples in different slaughterhouses to report the isolation along with the serotypes and antibiogram pattern of salmonella among products in tehran. salmonella was isolated from samples of chicken, beef; veal, mutton, roast beef and sausage fermentive meat collected at slaughterhouses. the isolates were characterized by serotyping and antimicrobial-susceptibility testing. eighty isolates of salmonella enterica belonging to 19 serotypes--s. adelaide, s. ...200719069997
variable number of tandem repeats (vntr) and its application in bacterial epidemiology.molecular epidemiology is the using of molecular techniques to study bacterial distribution in human populations. recently molecular epidemiologist benefit from several techniques such as variable number tandem repeat (vntr) typing method to typing bacterial strains. variable number tandem repeat (vntr) typing is a tool for genotyping and provides data in a simple and numeric format based on the number of repetitive sequences. vntr for first time identified in m. tuberculosis as mycobacterial in ...200719070072
nmr assignment of reduced form of copper, zinc superoxide dismutase from salmonella enterica.almost complete assignment (97%) of nmr resonances was obtained for the reduced, cu(i), form of prokaryotic cuznsod from salmonella enterica. 13c direct detection was used to complement the standard bouquet of 1h detected triple resonance experiments and contributed to the identification of proline backbone resonances and to side chains assignments of asx, glx and aromatic rings. this is the only complete assignment available for monomer sod from prokaryotic organisms.200719636828
genotypic characterization of antibiotic-resistant salmonella enteritidis isolates in dakar, senegal.it is well established that salmonella enterica is a major cause of food-borne disease worldwide. in africa, according to the who global salm-surv country data bank from 2000 to 2002 salmonella enterica serovar enteritidis was the most common serotype involved in human salmonellosis. in dakar this serotype of salmonella has been reported as a frequent and an increasing cause of human infection.200719734606
biosynthesis of proline.proline was among the last biosynthetic precursors to have its biosynthetic pathway unraveled. this review recapitulates the findings on the biosynthesis and transport of proline. glutamyl kinase (gk) catalyzes the atp-dependent phosphorylation of l-glutamic acid. purification of γ-gk from escherichia coli was facilitated by the expression of the prob and proa genes from a high-copy-number plasmid and the development of a specific coupled assay based on the nadph-dependent reduction of gp by γ-g ...200726443591
regulation of fimbrial expression.fimbria-mediated interaction with the host elicits both innate and adaptive immune responses, and thus their expression may not always be beneficial in vivo. furthermore, the metabolic drain of producing fimbriae is significant. it is not surprising, therefore, to find that fimbrial production in escherichia coli and salmonella enterica is under extensive environmental regulation. in many instances, fimbrial expression is regulated by phase variation, in which individual cells are capable of swi ...200726443581
nadh as donor.the number of nadh dehydrogenases and their role in energy transduction in escherchia coli have been under debate for a long time. now it is evident that e. coli possesses two respiratory nadh dehydrogenases, or nadh:ubiquinone oxidoreductases, that have traditionally been called ndh-i and ndh-ii. this review describes the properties of these two nadh dehydrogenases, focusing on the mechanism of the energy converting nadh dehydrogenase as derived from the high resolution structure of the soluble ...200726443579
epidemiological investigation of an outbreak of enteric fever.ninety five cases of enteric fever among military recruits from a regimental training centre at maharastra were admitted to the local military hospital in a few weeks time.200727408039
reemergence of chloramphenicol sensitivity in enteric fever.enteric fever is a global health problem and rapidly developing resistance to various drugs makes the situation more alarming. drug sensitivity in salmonella enterica serovar typhi and salmonella enterica serovar paratyphi a isolated from 45 blood culture positive cases of enteric fever was tested to determine in-vitro susceptibility pattern of prevalent strains in northern india.200727407999
clinical pathogenesis of typhoid fever.human infections with salmonella enterica results in two major groups of diseases: gastroenteritis and typhoid fever. clinical observations suggest that gastroenteritis, caused by non-typhoidal salmonella serovars, is characterized by a massive neutrophil influx, which keeps the infection localized to the intestinal mucosa. in contrast, the absence of neutrophilic intestinal infiltrates in the acute phase of typhoid fever suggests a propensity for typhoidal salmonella serovars (s. typhi, s. para ...200819741286
spi-7: salmonella's vi-encoding pathogenicity island.salmonella pathogenicity island-7 (spi-7) is a large, mosaic, genetic island, found in several serovars of salmonella enterica subsp. enterica associated with systemic disease. as well as encoding genes which may aid its own transmission, it carries genes for potential virulence factors such as vi antigen, sope effector and type ivb pili. the stability of spi-7 is of interest with respect to typhoid fever and related vaccines.200819741287
inchi plasmids, a dynamic link between resistance and pathogenicity.plasmids of incompatibility group (inc) hi1 are important vectors of antibiotic resistance in both of the major causal agents of enteric fever: salmonella enterica subspecies enterica serovar typhi and s. paratyphi a. in s. typhi, inchi1 plasmids appeared in the 1970s and spread globally. in some circumstances they are maintained within the bacterial population even in the absence of selection from antibiotics. the low cost associated with inch plasmids in salmonella is due, in part, to the pres ...200819741288
enteric fever in south china: guangxi province.guangxi is a province of china endemic for enteric fever. salmonella enterica serovar paratyphi a has been found to be causing more and more enteric fever episodes in the last 10 years, evident not only from routine surveillance but also from prospective population-based surveillance. the prevalent pattern of paratyphoid seen was different from typhoid since it mainly occurred in outbreaks. almost all strains collected from different areas and years in guangxi were resistance to nalidixic acid, ...200819741290
antibiotic resistance among salmonella enterica serovars typhi and paratyphi a in pakistan (2001-2006).to compare antimicrobial resistance in s. typhi and s. paratyphi a isolates from pakistan.200819741291
emergence of plasmid-mediated multidrug resistance in epidemic and non-epidemic strains of salmonella enterica serotype typhi from jordan.enteric fever caused by salmonella enterica serovar typhi has not been adequately explored in jordan.200819741292
association of carcinoma of the gallbladder with typhoid carriage in a typhoid endemic area using nested pcr.although well studied the association between chronic typhoid carrier state and carcinoma of the gallbladder (cagb) remains unproven.200819741293
mimotopes of heat shock proteins of salmonella enterica serovar typhi identified from phage-displayed peptide library.heat shock proteins (hsps) are known to be involved in the pathogenesis of salmonella enterica serovar typhi (s. typhi), the causative agent of typhoid fever. the objective of this study was to apply a phage display library to identify mimotopes of two hsps, hsp90 and dnak in s. typhi.200819741295
a case report and review of the literature: ciprofloxacin resistant salmonella enterica serovar typhi in india.enteric fever is a major public health problem in india. the current treatment of choice is the fluoroquinolones.200819741296
regulation of vi capsular polysaccharide synthesis in salmonella enterica serotype typhi.the synthesis of vi polysaccharide, a major virulence determinant in salmonella enterica serotype typhi (s. typhi), is under the control of two regulatory systems, ompr-envz and rscb-rscc, which respond to changes in osmolarity. some s. typhi isolates exhibit over-expression of vi polysaccharide, which masks clinical detection of lps o-antigen. this variation in vi polysaccharide and o-antigen display (vw variation) has been observed since the initial studies of s. typhi. we have reported that t ...200819745516
the laboratory diagnosis of enteric fever.the diagnosis of enteric fever currently depends upon the isolation of salmonella from a patient, most commonly by blood culture. this facility is not available in many areas where the disease is endemic. serodiagnosis depends upon the 100-year-old widal test, and other serological diagnostic tools have limitations because of their low sensitivity and/or specificity. the most promising recently published results are from pcr-based amplification of dna from the blood of enteric fever patients but ...200819745517
treatment of enteric fever.enteric fever is systemic illness caused by salmonella typhi and salmonella paratyphi a, b and c. it is believed to be a readily treatable illness by many clinicians in the developing world where it is endemic; however, with the emergence of drug resistance to fluoroquinolones, treatment is becoming increasingly difficult. while drugs such as cefixime, previously believed to be effective, have been proven otherwise, new agents such as gatifloxacin and azithromycin have proven to be promising. re ...200819745518
typhi genes expressed during infection or involved in pathogenesis.salmonella enterica serovar typhi (typhi), the aetiologic agent of typhoid fever, is a human restricted pathogen. elucidation of the interactions between the infected host and this pathogen is critical to understand infectious diseases but is deterred by a lack of in vivo infection assays, since typhi uniquely infects humans and there is no suitable animal model. macrophages can be used as an alternative model, as the ability to survive and replicate within these cells is thought to be one of th ...200819745519
invasive salmonellosis in malawi.the incidence of invasive salmonellosis has increased among children and hiv-infected adults in malawi. this has been associated with the emergence of drug resistance in the non-typhoidal salmonella serovars enteritidis and typhimurium. in contrast, s. typhi isolates have remained fully sensitive to commonly used antibiotics and the estimated incidence of typhoid fever, although still present, has fallen slightly among both adults and children. infection with s. typhi is not closely associated w ...200819745520
typhoid fever in sub-saharan africa: challenges of diagnosis and management of infections.typhoid fever, caused by salmonella enterica serovar typhi (s. typhi), is a disease transmitted by the faecal-oral route. it continues to be a public health problem in many developing countries in sub-saharan africa. school-age children, especially those from resource-poor settings with inadequate water and sanitation systems, are disproportionately affected. it is estimated that a total of 400,000 cases occur annually in africa, an incidence of 50 per 100,000 persons per year. lack of effective ...200819745521
typhoid fever in ethiopia.this review focuses on the reports of salmonellosis by investigators in different parts of ethiopia, in particular focusing on the levels of typhoid fever. many of the reports are published in local journals that are not available online. there have been seven studies which diagnosed typhoid fever by laboratory culture and there is no coordinated epidemiological surveillance. all conducted research and reports from different health institutions in ethiopia indicate that typhoid fever was still a ...200819745522
epidemiology of typhoid and paratyphoid fever in india.enteric fever (typhoid and paratyphoid fever) is a major human bacterial infection. although the disease is not common in industrialised countries, it remains an important and persistent health problem in developing nations. hospital-based studies and outbreak reports from india indicate that enteric fever is a major public health problem in this country, with salmonella enterica serovar typhi (s. typhi) the most common aetiologic agent but with an apparently increasing number of cases due to s. ...200819745523
tlr4-induced ifn-gamma production increases tlr2 sensitivity and drives gram-negative sepsis in mice.gram-negative bacterial infection is a major cause of sepsis and septic shock. an important inducer of inflammation underlying both syndromes is the cellular recognition of bacterial products through pattern recognition receptors (prrs), including toll-like receptors (tlrs). we identified a novel antagonistic mab (named 1a6) that recognizes the extracellular portion of the tlr4-md-2 complex. if applied to mice before infection with clinical isolates of salmonella enterica or escherichia coli and ...200818644971
salmonella administration induces a reduction of wheel-running activity via a tlr5-, but not a tlr4, dependent pathway in mice.in general, systemic bacterial infections induce sickness behavior. in mice, lipopolysaccharide (lps), a component of gram-negative bacteria, strongly reduces physical activity via toll-like receptor (tlr) 4. however, gram-negative bacteria, such as salmonella, also express flagella containing flagellin (fg) which binds to tlr5 and induces pro-inflammatory cytokine production. it is unclear whether fg induces sickness behavior. to determine whether salmonella administration regulates the reducti ...200819203083
[report on typhoid fever case in maringá, state of paraná].typhoid fever is an acute bacterial disease caused by salmonella enterica serotype typhi, which is acquired by consumption of contaminated food or water. this paper had the aim of describing a case of typhoid fever that occurred in maringá, state of paraná, after three years without any notifications of the disease.200819142452
transmission of salmonella between wildlife and meat-production animals in denmark.to investigate the transmission of salmonella spp. between production animals (pigs and cattle) and wildlife on production animal farms in denmark.200819146492
effects of repeated cycles of acid challenge and growth on the phenotype and virulence of salmonella enterica.the aim of the study was to investigate how stresses like low ph, which may be encountered in farms or food preparation premises, shape populations of salmonella enterica by the selection of stress-resistant variants.200819146498
regulation of mara, soxs, rob, acrab and micf in salmonella enterica serovar typhimurium.importance of the overexpression of acrab efflux pumps in the low-level resistance of pathogens to antimicrobials requires a better understanding of the acrab regulation. the goal of the present research was to study the transcription of acrab, as well as the genes that play a role in its regulation in salmonella enterica serovar typhimurium. we monitored the transcription of these genes during growth at 30 degrees c and 37 degrees c, and thoroughly studied the effect of salicylate, paraquat and ...200819120970
[mechanism of interaction of tumor necrosis factor (tnf-alpha) of macroorganism with the salmonella enterica cells (ser. typhimurium)].the goal of this work was to elucidate the mechanism of direct interaction of bacterial cells with tumor necrosis factor (tnf-alpha; cytokine). it was shown earlier that this interaction facilitated activation of bacterial growth and recultivation of non-cultivated forms in vitro and in vivo. it was shown in experiments with mice deficient in the genes encoding eucaryotic tnf-alpha receptors and infected with salmonella that addition of exogenous tnf-alpha to suspension of infection cells caused ...200819172874
dna recognition by the salmonella enterica serovar typhimurium transcription factor slya.the salmonella regulatory protein slya is implicated in virulence, survival in macrophages and resistance to oxidative stress and anti-microbial peptides. slya is a member of the marr family of winged-helix transcription factors. systematic mutational analysis of the slya operator sequence and of the predicted dna-binding region of slya shows that no single base pair in the palindromic slya operator sequence is essential for dna binding, and identifies amino acid residues required to allow slya ...200819204896
intestinal mmc-related electric fields and pancreatic juice control the adhesion of gram-positive and gram-negative bacteria to the gut epithelium--in vitro study.the adhesion of six different lactobacillus and lactococcus and three pathogenic escherichia and salmonella strains was studied using caco-2 cell line. in this in vitro model system the influence of weak electric field (ef) on bacterial adhesion was tested. the ef source was the in vitro reconstruction of spiking potentials recorded in the duodenum of a healthy calf during one myoelectrical migration complex (mmc) cycle. the ability to adhere to caco-2 cells of bacteria belonging to two groups, ...200819212012
construction of highly attenuated salmonella enterica serovar typhimurium live vectors for delivering heterologous antigens by chromosomal integration.attenuated live salmonella enterica serovar typhimurium is a versatile organism for the generation of live recombinant vaccines for mucosal immunization and various approaches were devised for the stable and efficient expressions of heterologous antigens by attenuated s. enterica strains. phage lamda red recombinase has recently been devised for gene replacements in s. enterica after introduction of pcr products as a one-step deletion approach and flp-mediated recombination allows the subsequent ...200819216101
genotyping and antimicrobial susceptibility of salmonella enterica serotype panama isolated in taiwan.previous studies have indicated that salmonella enterica serotype panama causes systemic infections in humans. the present study was undertaken to gain more understanding of the molecular epidemiology and antimicrobial resistance of salmonella panama.200819255695
rapid detection of salmonella in foods using real-time pcr.conventional methods for detection of salmonella serovars in foods are generally time-consuming and labor intensive. a real-time pcr method has been developed with custom designed primers and a taqman probe to detect the presence of a 262-bp fragment of the salmonella-specific inva gene. the method has been tested with a total of 384 field-isolated salmonella serovars and non-salmonella stock strains, as well as 420 u.s. food and drug administration food samples, comprising a variety of food mat ...200819256088
cross-protective effect of acid-adapted salmonella enterica on resistance to lethal acid and cold stress conditions.to evaluate the cross-protected salmonella enterica cells under acid and cold stress conditions.200819241522
salmonella sofia differs from other poultry-associated salmonella serovars with respect to cell surface hydrophobicity.salmonella enterica is one of the most important foodborne pathogens. salmonella enterica subsp. ii 4,12:b:- (salmonella sofia) is commonly found in australian poultry. it has been suggested that physicochemical properties such as surface charge and hydrophobicity may affect bacterial attachment to surfaces and their ability to persist in food systems. a possible link between hydrophobicity cell surface charge and persistence of salmonella from the poultry system was examined. hydrophobicity of ...200819244894
splenic abscess due to salmonella enterica serotype typhi in a young adult. 200819245162
[application of pulsed-field gel electrophoresis in a food-borne outbreak of salmonella serotype muenchen infection].to investigate the application of pulsed-field gel electrophoresis (pfge) in food-borne outbreak.200819176144
effect of hemidesmus indicus r.br. root extract against salmonella enterica serovar typhimurium-induced apoptosis in murine macrophage cell line (p388d1).previous studies on natural products had mainly dealt with their antimicrobial activity and studies on the interference of these bioactive compounds with host-bacterial interaction is limited. the present study was undertaken to investigate the effect of the sterols and fatty acids present in the chloroform fraction of crude methanol extract of hemidesmus indicus root (chi) on salmonella enterica serovar typhimurium (s. typhimurium) mediated apoptosis in a murine macrophage cell line (p388d1).200819179687
evaluation of genome-derived amplicon length polymorphism pcr primers for the genetic evaluation of related strains of salmonella.the intent of this study is to exploit both the genetic diversity and conservation demonstrated between the salmonella enterica ssp. enterica serovar typhi ct18 and salm. enterica ssp. enterica serovar typhimurium lt2 genomes by utilizing amplicon length polymorphism (alp) to detect and differentiate various salmonella strains.200819552779
differentially evolved genes of salmonella pathogenicity islands: insights into the mechanism of host specificity in salmonella.the species salmonella enterica (s. enterica) includes many serovars that cause disease in avian and mammalian hosts. these serovars differ greatly in their host range and their degree of host adaptation. the host specificity of s. enterica serovars appears to be a complex phenomenon governed by multiple factors acting at different stages of the infection process, which makes identification of the cause/s of host specificity solely by experimental methods difficult.200819050757
detection of salmonella enterica serotype typhimurium dt104 in mozambique.the spread of salmonella enterica serotype typhimurium definitive phage type dt104 in sub-saharan africa is a public health concern. we obtained two isolates of s. typhimurium dt104 from blood cultures of infants with malaria in mozambique. both isolates contained salmonella genomic island 1a and had the same pulsed-field gel electrophoresis pulsenet pattern (stymxb.0005). results showed the need for continuous surveillance of salmonella spp. serotypes circulating in this area.200819052305
typhoid fever in southern taiwan: a medical center experience.typhoid fever is caused by salmonella enterica serotype typhi (5. typhi). growing communication between taiwan and neighboring regions in recent years could be an important source of typhoid fever. the aim of this study was to analyze the clinical characteristics of typhoid fever treated at a medical center in southern taiwan.200819054916
[antagonistic properties of enterococci isolated from gastrointestinal tract of long-livers].the strains with antagonistic activity against indicator strains pseudomonas aeruginosa, proteus vulgaris, staphylococcus aureus, staphylococcus epidermidis, escherichia coli, klebsiella pneumonia, salmonella enterica were revealed among 58 enterococcus strains isolated from gastrointestinal tract of long-livers. the influence of different components of mrs medium on the antagonistic effect was established. antagonistic activity remained on the medium without glucose in 36% of strains, on the me ...200819044009
risk associated with transportation and lairage on hide contamination with salmonella enterica in finished beef cattle at slaughter.transportation of cattle to the slaughter plant could influence hide contamination with salmonella enterica. fecal and hide samples were obtained from 40 lots of cattle at the feedlot and again at the slaughter plant. potential risk factors for hide contamination were evaluated. a multilevel poisson regression model was used to determine whether transportation and lairage were associated with hide contamination by salmonella. cattle with hide samples positive for salmonella at the feedlot had tw ...200819044266
differentiation of salmonella enterica serovars and strains in cultures and food using infrared spectroscopic and microspectroscopic techniques combined with soft independent modeling of class analogy pattern recognition analysis.detection of pathogenic microorganisms in food is often a tedious and time-consuming exercise. developing rapid and cost-effective techniques for identifying pathogens to subspecies is critical for tracking causes of foodborne disease outbreaks. the objective of this study was to develop a method for rapid identification and differentiation of salmonella serovars and strains within these serovars through isolation on hydrophobic grid membrane filters (hgmfs), examination by infrared (ir) spectro ...200819044269
inactivation of salmonella enterica serovar senftenberg 775w in liquid whole egg by ultrahigh pressure homogenization.two batches of samples of liquid whole egg were inoculated with a load of approximately 3 and 7 log cfu/ml, respectively, of salmonella enterica serovar senftenberg 775w and submitted to different ultrahigh pressure homogenization (uhph) treatments at 150, 200, and 250 mpa. the inlet temperature of the samples was 6 degrees c. counts of viable and injured salmonella cells were obtained 2 h after the uhph treatments and after 5, 10, 15, and 20 days of storage at 4 degrees c. the level of pressure ...200819044274
development of unique bacterial strains for use as positive controls in the food microbiology testing laboratory.nalidixic acid-resistant (nalr) mutants of salmonella enterica serovar berta and escherichia coli o157:h7 were derived from wild-type laboratory cultures to serve as distinguishable control strains for routine use in food microbiology testing programs. the prevalence of the nalr phenotype among different bacteria was verified using panels of related and unrelated strains with the ability to grow vigorously on plating media containing nalidixic acid, being restricted to the nalr mutants. the nalr ...200819044277
analysis of salmonella enterica with reduced susceptibility to the third-generation cephalosporin ceftriaxone isolated from u.s. cattle during 2000-2004.over the past decade enteric bacteria in europe, africa, and asia have become increasingly resistant to cephalosporin antimicrobial agents. this is largely due to the spread of genes encoding extended-spectrum beta-lactamase (esbl) enzymes that can inactivate many cephalosporins. recently, these resistance mechanisms have been identified in salmonella isolated from humans in the united states. due to the potential for transmission of resistant bacteria to humans via food animals, salmonella anim ...200819025468
burkholderia cenocepacia-induced delay of acidification and phagolysosomal fusion in cystic fibrosis transmembrane conductance regulator (cftr)-defective macrophages.the burkholderia cepacia complex (bcc) is a group of opportunistic bacteria chronically infecting the airways of patients with cystic fibrosis (cf). several laboratories have shown that bcc members, in particular b. cenocepacia, survive within a membrane-bound vacuole inside phagocytic and epithelial cells. we have previously demonstrated that intracellular b. cenocepacia causes a delay in phagosomal maturation, as revealed by impaired acidification and slow accumulation of the late phagolysosom ...200819047750
salmonella translocates across an in vitro m cell model independently of spi-1 and spi-2.we have used an in vitro model of intestinal m cells to examine the mechanisms by which salmonella enterica translocates across these specialized cells, which constitute a primary site of infection of the mammalian host. s. enterica can invade cultured cells by deploying a type iii secretion system (ttss) encoded within salmonella pathogenicity island 1 (spi-1) to translocate effector proteins into the host cell cytoplasm that trigger cellular responses, including prominent cytoskeletal rearrang ...200819047755
contamination of chicken meat with salmonella enterica serovar haardt with nalidixic acid resistance and reduced fluoroquinolone susceptibility.salmonella contamination in chicken meat was studied with 100 chicken meat samples purchased from 55 shops located in various regions. a total of 21 isolates of salmonella enterica were isolated from 21 chicken meat samples from four shops located at open markets, whereas there were none from supermarkets with well-equipped cold systems. among these, 18 isolates were identified as salmonella enterica serotype haardt (s. haardt) and three isolates were s. enterica serotype muenchen. when the mini ...200819047832
outbreak of salmonella thompson infection in a swedish dairy herd.salmonella typhimurium was isolated from a faecal sample from a cow in a swedish dairy herd after calving. when investigations were undertaken in the herd, salmonella thompson was isolated from heifers on a separate pasture, and when these heifers were brought into the herd s thompson spread rapidly. control strategies managed to rid the herd of the s typhimurium infection and the prevalence of s thompson was at first substantially reduced. there was a rapid increase in its prevalence when the a ...200819011246
the solution structure of the monomeric copper, zinc superoxide dismutase from salmonella enterica: structural insights to understand the evolution toward the dimeric structure.the structure of the sodcii-encoded monomeric cu, zn superoxide dismutase from salmonella enterica has been solved by nmr spectroscopy. this represents the first solution structure of a natural and fully active monomeric superoxide dismutase in solution, providing information useful for the interpretation of the evolutional development of these enzymes. the protein scaffold consists of the characteristic beta-barrel common to the whole enzyme family. the general shape of the protein is quite sim ...200819006322
risk factors for infection with pathogenic and antimicrobial-resistant fecal bacteria in northern elephant seals in california.the goal of this study was to identify potential environmental and demographic factors associated with campylobacter jejuni (c. jejuni), salmonella enterica (salmonella spp.), and antimicrobial-resistant escherichia coli (e. coli) infection in northern elephant seals stranded along the california coastline.200819006978
a reservoir of drug-resistant pathogenic bacteria in asymptomatic hosts.the population genetics of pathogenic bacteria has been intensively studied in order to understand the spread of disease and the evolution of virulence and drug resistance. however, much less attention has been paid to bacterial carriage populations, which inhabit hosts without producing disease. since new virulent strains that cause disease can be recruited from the carriage population of bacteria, our understanding of infectious disease is seriously incomplete without knowledge on the populati ...200819015729
protective immunity to systemic infection with attenuated salmonella enterica serovar enteritidis in the absence of il-12 is associated with il-23-dependent il-22, but not il-17.il-12 is essential for protective t cell-mediated immunity against salmonella infection. to characterize the role of the related cytokine il-23, wild-type (wt) c57bl/6 and p19(-/-) mice were infected systemically with an attenuated strain of salmonella enterica serovar enteritidis (s. enteritidis). il-23-deficient mice controlled infection with s. enteritidis similarly as wt mice. similar ifn-gamma production as compared with wt mice, but defective il-17a and il-22 production was found in the ab ...200819017979
polyhexamethylene guanidine hydrochloride-based disinfectant: a novel tool to fight meticillin-resistant staphylococcus aureus and nosocomial infections.polyhexamethylene guanidine hydrochloride (phmgh), an antimicrobial biocide of the guanidine family, was tested for efficacy against quality-control strains of staphylococcus aureus, pseudomonas aeruginosa, salmonella choleraesuis, meticillin-resistant s. aureus (mrsa) and escherichia coli. bactericidal activity against s. aureus, p. aeruginosa and salmonella choleraesuis was determined using the official methods of analysis of the association of official analytical chemists, with modifications ...200819018024
role of global regulator rma for multidrug efflux-mediated fluoroquinolone resistance in salmonella.the genetic basis for multidrug resistance (mdr) due to overexpression of mdr efflux pumps in escherichia coli usually includes alterations in genes encoding global regulators, like mara, soxs, and rob. in salmonella, in addition to these regulators, rma, for which no homolog exists in e. coli, seems to play a role in the regulation of efflux pumps. however, the exact mechanisms remain unclear. therefore, this study aimed at investigating the influence of the regulator rma on the expression of m ...200819018673
biological and antibacterial activities of the natural herb houttuynia cordata water extract against the intracellular bacterial pathogen salmonella within the raw 264.7 macrophage.salmonellosis is a major bacterial zoonosis that causes a variety of disease syndromes, from self-limiting enteritis to fatal infection in animals and food-borne infection and typhoid fever in humans. recently, the emergence of multidrug-resistant strains of salmonella sp. has caused more serious problems in public health. the present study investigated the antibacterial effects of houttuynia cordata water extract (hcwe) against murine salmonellosis. in raw 264.7 cells, there was no detectable c ...200818981565
assessment of antibiotic resistance phenotype and integrons in salmonella enterica serovar typhimurium isolated from swine.salmonella enterica serovar typhimurium (s. typhimurium) isolated and identified from swine were subjected for the analysis of antibiotic resistance pattern and clinically important class 1 and 2 integrons. in addition, s. typhimurium isolates exhibiting ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, tetracycline and florfenicol (acssutf) resistance pattern as described in most salmonella enterica serotype typhimurium definitive type 104 (dt104) were characterized by polymerase cha ...200818981675
maintenance of the salmonella-containing vacuole in the juxtanuclear area: a role for intermediate filaments.until recently, intermediate filaments (if) were thought to be only involved in resistance to physical stress and mechanical integrity of cells and tissues. recent data indicate that if play a much more important role in cellular physiology including organelle structure and positioning within the cell. here, we show that salmonella enterica serovar typhimurium (s. typhimurium) induces in epithelial cells and macrophages the formation of an aggresome-like structure with a dramatic remodelling of ...200818977288
update: recall of dry dog and cat food products associated with human salmonella schwarzengrund infections--united states, 2008.on may 16, 2008, cdc reported on a 2006-2007 multistate outbreak of infection with salmonella enterica serotype schwarzengrund that was associated with dry dog food. at the time of that report, a total of 70 cases had been reported from 19 states, with the last case identified on october 1, 2007. subsequently, an additional case was identified on december 29, 2007. epidemiologic and environmental investigations have suggested the source of the outbreak was dry pet food produced by one manufactur ...200818987615
mutants of the rna-processing enzyme rnase e reverse the extreme slow-growth phenotype caused by a mutant translation factor ef-tu.salmonella enterica with mutant ef-tu (gln125arg) has a low level of ef-tu, a reduced rate of protein synthesis and an extremely slow growth rate. eighty independent suppressor mutations were selected that restored normal growth. in some cases (n= 7) suppression was due to mutations in tufa but, surprisingly, in most cases (n= 73) to mutations in rne, the gene coding for rnase e. these rne mutations alone had only modest effects on growth rate. fifty different suppressor mutations were isolated ...200818990188
the role of interleukin-12 in the heavy metal-elicited immunomodulation: relevance of various evaluation methods.abstract:200818990205
gene expression profiling in chicken heterophils with salmonella enteritidis stimulation using a chicken 44 k agilent microarray.salmonella enterica serovar enteritidis (se) is one of the most common food-borne pathogens that cause human salmonellosis and usually results from the consumption of contaminated poultry products. the mechanism of se resistance in chickens remains largely unknown. previously, heterophils isolated from broilers with different genetic backgrounds (se-resistant [line a] and -susceptible [line b]) have been shown to be important in defending against se infections. to dissect the interplay between h ...200818990222
characterization of multidrug-resistant salmonella enterica serovar heidelberg isolated from humans and animals.salmonella enterica serovar heidelberg has been recognized as one of the most common serovar associated with foodborne infections in the united states. it is also frequently isolated from nonhuman sources and has increasingly shown resistance to various antimicrobial agents. the present study was undertaken to identify the predominant antimicrobial resistance phenotypes and genotypes of salmonella heidelberg (n = 95) isolates of human, swine, and turkey origin. antimicrobial susceptibility was d ...200818991546
excess of infections due to a multi-drug sensitive salmonella enterica serotype typhimurium in france in june 2008.an unusually high number of cases of salmonella typhimurium was reported in france in june 2008. in the course of epidemiological investigations 112 cases were ascertained, of whom 75 were interviewed. subtyping by pfge and mlva identified a strain named "majority profile". subtyping results were available for 45 interviewed cases, 30 of whom (majority below 15 years of age) were found to be infected with the majority profile strain. evidence suggested the occurrence of an outbreak due to a mono ...200819000564
outbreak of salmonella enterica serovar typhimurium in switzerland, may-june 2008, implications for production and control of meat preparations.an increased number of salmonella typhimurium cases were reported in switzerland between may and june 2008. investigations involved 72 cases. results of pfge typing identified several outbreak strains, the dominating one present in 43 of the 72 isolates. strains affecting one third of the cases were also found in animal samples, in particular pork. however, no specific food source could be identified. outbreaks described in this paper highlight the importance of food safety regulations such as t ...200819000565
dexamethasone modulates salmonella enterica serovar typhimurium infection in vivo independently of the glucocorticoid-inducible protein annexin-a1.salmonella enterica serovar typhimurium (s. typhimurium) infection causes an inflammatory response through activation of toll-like receptor 4 by lipopolysaccharide. dexamethasone, a glucocorticoid analogue, suppresses inflammatory responses by many mechanisms including inhibition of the lipopolysaccharide-induced production of proinflammatory mediators. there is little information on the effect of glucocorticoids on murine salmonellosis. in this study, we treated susceptible balb/c mice by subcu ...200819049646
genomic analysis of bacteriophage epsilon 34 of salmonella enterica serovar anatum (15+).the presence of prophages has been an important variable in genetic exchange and divergence in most bacteria. this study reports the determination of the genomic sequence of salmonella phage epsilon 34, a temperate bacteriophage that was important in the early study of prophages that modify their hosts' cell surface and is of a type (p22-like) that is common in salmonella genomes.200819091116
analysis of the role of 13 major fimbrial subunits in colonisation of the chicken intestines by salmonella enterica serovar enteritidis reveals a role for a novel locus.salmonella enterica is a facultative intracellular pathogen of worldwide importance. over 2,500 serovars exist and infections in humans and animals may produce a spectrum of symptoms from enteritis to typhoid depending on serovar- and host-specific factors. s. enteritidis is the most prevalent non-typhoidal serovar isolated from humans with acute diarrhoeal illness in many countries. human infections are frequently associated with direct or indirect contact with contaminated poultry meat or eggs ...200819091138
a simple screen to identify promoters conferring high levels of phenotypic noise.genetically identical populations of unicellular organisms often show marked variation in some phenotypic traits. to investigate the molecular causes and possible biological functions of this phenotypic noise, it would be useful to have a method to identify genes whose expression varies stochastically on a certain time scale. here, we developed such a method and used it for identifying genes with high levels of phenotypic noise in salmonella enterica ssp. i serovar typhimurium (s. typhimurium). ...200819096504
rapid real-time pcr assay for detecting salmonella in raw and ready-to-eat meats.a real-time pcr assay was evaluated for the rapid detection (10 h) of salmonella in meats using molecular beacon probes available as a commercial kit (iq-check, bio-rad laboratories). raw (chicken, pork) and ready-to-eat (rte) meats were artificially contaminated with salmonella enterica serovar typhimurium at the estimated level of 2 to 4 cells per 25 g. after 8 h of pre-enrichment in buffered peptone water, a molecular beacon-based pcr assay was performed to detect contamination in raw and rte ...200819149100
[invasive salmonella dublin infection in a case]. 200819099872
[increased liver enzymes and fever]. 200819100197
phage type and antimicrobial susceptibility of salmonella enterica serovar enteritidis from food-producing animals in japan between 1976 and 2004.a total of 56 isolates of salmonella enterica serovar enteritidis, including 38 isolates from poultry, 16 from cattle and two from pigs, collected between 1976 and 2004, were subjected to bacteriophage typing and antimicrobial susceptibility testing. phage type (pt) 8 was predominant in bovine isolates, whereas pt1 and pt4 were predominant in poultry isolates. resistance was found for 8 of 11 antimicrobials tested, at the following rates: 46.4% for dihydrostreptomycin followed by ampicillin and ...200819123313
bacteriological detection of salmonella enteritidis in eggs: a review.the detection of salmonella enterica serovar enteritidis (se) in eggs is hampered by a typically low prevalence of contaminated eggs, the low number of se organisms in such eggs, and the presence of inhibitory substances in the egg albumin. for these reasons, the analysis of large pools of eggs is normally necessary, which presents logistic and microbiological challenges associated with a low number of target organisms from a large volume of sample matrix. in some studies using artificially inoc ...200819284035
emerging trends in enteric fever in nepal: 9124 cases confirmed by blood culture 1993-2003.this was a retrospective study in an urban hospital in kathmandu, nepal to determine the changing burden of salmonella septicaemia, the proportion of salmonella paratyphi a, and the emergence of drug-resistant organisms. the participants were outpatients and inpatients over the period 1993-2003, and the main outcome measures were blood culture isolates and antibiotic sensitivity testing. the results showed that of 82467 blood cultures performed, a bacterium was isolated from 12252. salmonella ac ...200818023462
cloning, expression and characterization of heat shock protein 60 (groel) of salmonella enterica serovar typhi and its role in protective immunity against lethal salmonella infection in mice.heat shock proteins (hsps) represent dominant antigens in numerous microbial infections, suggesting a potential use of pathogen-derived hsps for vaccination. the present study evaluates the immunogenicity and protective efficacy of groel (hsp60) of salmonella enterica serovar typhi against lethal challenge by s. typhi ty2 and salmonella enterica serovar typhimurium in mice. the groel gene was cloned and expressed in escherichia coli bl21 and purified by affinity chromatography. immunization of m ...200818024219
luxs affects flagellar phase variation independently of quorum sensing in salmonella enterica serovar typhimurium.luxs catalyzes the synthesis of the quorum-sensing signaling molecule autoinducer 2. we show that in salmonella enterica serovar typhimurium, deletion of the luxs gene polarizes flagellar phase variation toward the more immunogenic phase 1 flagellin. this phenotype is complementable by luxs in trans but is independent of quorum-sensing signals.200818024511
salmonella enterica burden in harvest-ready cattle populations from the southern high plains of the united states.our objectives were to quantify the salmonella enterica burdens in harvest-ready cattle and to identify specific at-risk populations of cattle most likely to harbor multiply resistant s. enterica. hide swabs were collected in abattoirs from three cohorts of cattle (feedlot origin cattle that had achieved desirable harvest characteristics and dairy- and beef-type cows harvested because of poor productivity). feces were collected from two cohorts housed in feedlots (cattle that had achieved desira ...200818024678
influence of gastric acid on susceptibility to infection with ingested bacterial pathogens.despite the widely held belief that gastric acid serves as a barrier to bacterial pathogens, there are almost no experimental data to support this hypothesis. we have developed a mouse model to quantify the effectiveness of gastric acid in mediating resistance to infection with ingested bacteria. mice that were constitutively hypochlorhydric due to a mutation in a gastric h(+)/k(+)-atpase (proton pump) gene were infected with yersinia enterocolitica, salmonella enterica serovar typhimurium, citr ...200818025100
the role of the qsec quorum-sensing sensor kinase in colonization and norepinephrine-enhanced motility of salmonella enterica serovar typhimurium.transcriptional analysis of salmonella enterica serovar typhimurium (s. typhimurium) in the presence of the mammalian hormone norepinephrine revealed up-regulation of genes in the flagellar and chemotaxis regulon. motility assays confirmed enhanced motility of wild-type s. typhimurium in the presence of norepinephrine that could be blocked by the alpha-adrenergic antagonist, phentolamine. furthermore, a mutation in the qsec gene, encoding the sensor kinase of the two-component qsebc quorum-sensi ...200817997077
immunological responses against salmonella enterica serovar typhimurium braun lipoprotein and lipid a mutant strains in swiss-webster mice: potential use as live-attenuated vaccines.we generated and characterized salmonella enterica serovar typhimurium mutants that were deleted for the genes encoding braun lipoprotein (lpp) alone or in conjunction with the msbb gene, which codes for an enzyme required for the acylation of the lipid a moiety of lipopolysaccharide. two copies of the lpp gene, designated as lppa and lppb, exist on the chromosome of s. typhimurium. these mutants were highly attenuated in a mouse infection model and induced minimal histopathological changes in m ...200817997275
salmonella infection of afferent lymph dendritic cells.the interactions of salmonella enterica subspecies i serotype abortusovis (s. abortusovis) with ovine afferent lymph dendritic cells (aldcs) were investigated for their ability to deliver maedi visna virus (mvv) gag p25 antigens to aldcs purified from afferent lymph. salmonellae were found to enter aldc populations by a process of cell invasion, as confirmed by electron and confocal microscopy. this led to phenotypical changes in aldc populations, as defined by cd1b and cd14 expression. no diffe ...200817986631
the role of roof rats ( rattus rattus) in the spread of salmonella enteritidis and s. infantis contamination in layer farms in eastern japan.the prevalence of salmonella in four layer farms in eastern japan was investigated between 2004 and 2006 to determine the role of roof rats (rattus rattus) in the epizootology of salmonella enterica subsp. enterica serovar enteritidis (s. enteritidis). persistent s. enteritidis and s. infantis contamination of the environment and pooled egg samples were detected in three out of four layer farms. a total of 113 (13.3%) and 158 (18.6%) out of 851 rats examined were positive for s. enteritidis and ...200817988423
effect of fixed or changing temperatures during prolonged storage on the growth of salmonella enterica serovar enteritidis inoculated artificially into shell eggs.the fate of salmonella enterica serovar enteritidis (se) in whole, unbroken eggs was monitored during storage at fixed or changing temperatures after inoculation with 20-47 c.f.u. of se. eggs stored at 10 degrees c and 20 degrees c showed little or no bacterial growth over 6 weeks, while egg storage at 30 degrees c increased the percentage of the eggs that contained >10(6) c.f.u. after 3 weeks. egg storage at 20 degrees c for 5 days followed by 10 degrees c caused only a few eggs with >10(6) c.f ...200817988424
the leucine-responsive regulatory protein, lrp, activates transcription of the fim operon in salmonella enterica serovar typhimurium via the fimz regulatory gene.the fim operon of salmonella enterica serovar typhimurium encodes type 1 fimbriae. the expression of fim is controlled in response to environmental signals through a complex regulatory cascade involving the proteins fimw, fimy, and fimz and a genetic locus, fimu, that encodes a rare arginine trna. we discovered that a knockout mutation in lrp, the gene that codes for the leucine-responsive regulatory protein (lrp), inhibited fim transcription. the loss of fim gene expression was accompanied by a ...200817981960
one pathway can incorporate either adenine or dimethylbenzimidazole as an alpha-axial ligand of b12 cofactors in salmonella enterica.corrinoid (vitamin b12-like) cofactors contain various alpha-axial ligands, including 5,6-dimethylbenzimidazole (dmb) or adenine. the bacterium salmonella enterica produces the corrin ring only under anaerobic conditions, but it can form "complete" corrinoids aerobically by importing an "incomplete" corrinoid, such as cobinamide (cbi), and adding appropriate alpha- and beta-axial ligands. under aerobic conditions, s. enterica performs the corrinoid-dependent degradation of ethanolamine if given ...200817981976
evidence of lethal and sublethal injury in food-borne bacterial pathogens exposed to high-intensity pulsed-plasma gas discharges.to apply scanning electron microscopy, image analysis and a fluorescent viability stain to assess lethal and sublethal injury in food-borne bacteria exposed to pulsed-plasma gas discharges (ppgd).200817983430
a conserved toll-like receptor is required for caenorhabditis elegans innate immunity.pathogen recognition through toll-like receptors (tlrs) is crucial in order to mount an appropriate immune response against microorganisms. on the basis of a lack of evidence indicating that caenorhabditis elegans uses tlrs to elicit an immune response and on the absence of genes encoding rel-like transcription factors in its genome, it is believed that tlr-mediated immunity arose after coelomates split from pseudocoelomates and acoelomates. here, we show that c. elegans tol-1(nr2033) mutants ar ...200817975555
salmonella choleraesuis as an anticancer agent in a syngeneic model of orthotopic hepatocellular carcinoma.some anaerobic and facultative anaerobic bacteria represent novel therapeutic agents that have been recently applied in cancer therapy. previously, we found that salmonella choleraesuis in combination with cisplatin could retard tumor growth in the murine subsutaneous hepatocellular carcinoma (hcc) model. in this regard, we investigated the antitumor activity of s. choleraesuis in the ml-1 orthotopic tumor model. systemically administered s. choleraesuis accumulated within not only subcutaneous ...200817960612
oral vaccination with salmonella enterica as a cruzipain-dna delivery system confers protective immunity against trypanosoma cruzi.to stimulate both local and systemic immune responses against trypanosoma cruzi, salmonella enterica serovar typhimurium aroa was exploited as a dna delivery system for cruzipain (scz). in a murine model we compared scz alone (gi) or coadministered with salmonella carrying a plasmid encoding granulocyte-macrophage colony-stimulating factor (gii), as well as protocols in which scz priming was followed by boosting with recombinant cruzipain (rcz) admixed with either cpg-odn (giii) or malp-2, a syn ...200817967857
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