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structural insights into the function of the nicotinate mononucleotide:phenol/p-cresol phosphoribosyltransferase (arsab) enzyme from sporomusa ovata.cobamides (cbas) are cobalt (co) containing tetrapyrrole-derivatives involved in enzyme-catalyzed carbon skeleton rearrangements, methyl-group transfers, and reductive dehalogenation. the biosynthesis of cobamides is complex and is only performed by some bacteria and achaea. cobamides have an upper (coβ) ligand (5'-deoxyadenosyl or methyl) and a lower (coα) ligand base that contribute to the axial co coordinations. the identity of the lower coα ligand varies depending on the organism synthesizin ...201223039029
intracontinental spread of human invasive salmonella typhimurium pathovariants in sub-saharan africa.a highly invasive form of non-typhoidal salmonella (ints) disease has recently been documented in many countries in sub-saharan africa. the most common salmonella enterica serovar causing this disease is typhimurium (salmonella typhimurium). we applied whole-genome sequence-based phylogenetic methods to define the population structure of sub-saharan african invasive salmonella typhimurium isolates and compared these to global salmonella typhimurium populations. notably, the vast majority of sub- ...201223023330
development of a custom 16s rrna gene library for the identification and molecular subtyping of salmonella enterica.the use of 16s rrna gene sequencing within the regulatory workflow may help to reduce the time and labor involved in the identification and differentiation of salmonella enterica isolates. however, a comprehensive, standardized reference library is needed in order to use this method with regulatory samples. the goal of this project was to acquire 16s rrna partial and full gene sequences for a variety of s. enterica isolates and to use these sequences to build a custom 16s rrna reference library. ...201223022443
studies on the substrate specificity of a gdp-mannose pyrophosphorylase from salmonella enterica.a series of methoxy and deoxy derivatives of mannopyranose-1-phosphate (manp-1p) were chemically synthesized, and their ability to be converted into the corresponding guanosine diphosphate mannopyranose (gdp-manp) analogues by a pyrophosphorylase (gdp-manpp) from salmonella enterica was studied. evaluation of methoxy analogues demonstrated that gdp-manpp is intolerant of bulky substituents at the c-2, c-3, and c-4 positions, in turn suggesting that these positions are buried inside the enzyme ac ...201223019451
multidrug-resistant salmonella enterica, democratic republic of the congo. 201223017665
prevalence of quinolone resistance and mutations in the topoisomerase genes in salmonella enterica serotype enteritidis isolates from serbia.the prevalence of quinolone resistance was studied in salmonella enterica serotype enteritidis isolates collected during 2005-2010 in southern bačka county, serbia. a total of 878 clinical isolates were examined, among which 19 (2.2%) nalidixic acid (nal)-resistant s. enteritidis were detected by selection on agar plates containing 64 mg/l nal. antimicrobial susceptibility of the isolates was tested by the agar dilution method. according to clinical and laboratory standards institute (clsi) brea ...201222999768
comparison of dkgb-linked intergenic sequence ribotyping to dna microarray hybridization for assigning serotype to salmonella enterica.two dna-based methods were compared for the ability to assign serotype to 139 isolates of salmonella enterica ssp. i. intergenic sequence ribotyping (isr) evaluated single nucleotide polymorphisms occurring in a 5s ribosomal gene region and flanking sequences bordering the gene dkgb. a dna microarray hybridization method that assessed the presence and the absence of sets of genes was the second method. serotype was assigned for 128 (92.1%) of submissions by the two dna methods. isr detected mixt ...201222998607
[meningitis due to salmonella enterica]. 201222987268
reptile pets-associated salmonella enterica subspecies diarizonae gastroenteritis in a neonate. 201222982955
[salmonella multiphasic flagellar antigen].in the salmonella antigenic pattern, more than one phase of flagellar antigen is observed. the phase of flagellar antigen depends of the gene which encodes the protein building the filament of flagella. the flic gene encodes the 1st phase of flagellar antigen and the fljb gene encodes the 2nd phase of flagellar antigen. the third phase of flagellar antigen is encoded by one of the genes localized on the plasmid. expression of the fljb gene (part of the hinfljba operon) is regulated by a mechanis ...201222922144
oral administration of a combination of select lactic acid bacteria strains to reduce the salmonella invasion and inflammation of broiler chicks.one-day-old chicks are susceptible to infection by strains of salmonella enterica subspecies. because multistrain probiotics are suggested to be more effective than monostrain probiotics due to the additive and synergistic effects, in this study, we prepared a multistrain formula a (mfa) consisting of 4 lactic acid bacteria (lab) strains selected by enhancing the tnf-α production for mouse macrophage 264.7 cells. the antagonistic effect of this mfa against the cecal colonization, viscera invasiv ...201222912447
fis is essential for the stability of linear plasmid pbssb1 and affects the motility of salmonella enterica serovar typhi.pbssb1 is a 27 kb non-bacteriophage-related linear plasmid first found in salmonella enterica serovar typhi (s. typhi), but the mechanism underlying the replication of pbssb1 is currently unknown. previous reports showed that the factor for inversion stimulation (fis) encoded by fis can affect the replication, transcription and other processes through binding dna. here, a fis deletion mutant of s. typhi (δfis) was prepared through the homologous recombination mediated by suicide plasmid and the ...201222911678
immediate after birth transmission of epidemic salmonella enterica typhimurium monophasic strains in pigs is a likely event. 201222904242
a comprehensive subcellular proteomic survey of salmonella grown under phagosome-mimicking versus standard laboratory conditions.towards developing a systems-level pathobiological understanding of salmonella enterica, we performed a subcellular proteomic analysis of this pathogen grown under standard laboratory and phagosome-mimicking conditions in vitro. analysis of proteins from cytoplasmic, inner membrane, periplasmic, and outer membrane fractions yielded coverage of 25% of the theoretical proteome. confident subcellular location could be assigned to over 1000 proteins, with good agreement between experimentally observ ...201222900174
suppressor analyses identify threonine as a modulator of rida mutant phenotypes in salmonella enterica.the rida (yjgf/yer057c/uk114) family of proteins is broadly conserved in the three domains of life yet the functional understanding of these proteins is at an early stage. physiological studies of rida mutant strains of salmonella enterica provided a framework to inform in vitro studies and led to the description of a conserved biochemical activity for this family. rida mutant strains of s. enterica have characteristic phenotypes including new synthesis of thiamine biosynthetic intermediate phos ...201222900093
pathways of genetic adaptation: multistep origin of mutants under selection without induced mutagenesis in salmonella enterica.in several bacterial systems, mutant cell populations plated on growth-restricting medium give rise to revertant colonies that accumulate over several days. one model suggests that nongrowing parent cells mutagenize their own genome and thereby create beneficial mutations (stress-induced mutagenesis). by this model, the first-order induction of new mutations in a nongrowing parent cell population leads to the delayed accumulation of visible colonies. in an alternative model (selection only), sel ...201222887815
detection of salmonella enterica isolates producing ctx-m cephalosporinase in u.s. livestock populations.we report the detection of salmonella carrying bla(ctx-m) in u.s. livestock populations. we identified 12 of 2,034 (0.6%) salmonella isolates originating from turkeys, horses, and pigs from at least 6 u.s. states, all carrying bla(ctx-m-1), many on a pandemic sequence type 1 incn plasmid.201222885753
human infections attributable to the d-tartrate-fermenting variant of salmonella enterica serovar paratyphi b in germany originate in reptiles and, on rare occasions, poultry.in this study, the population structure, incidence, and potential sources of human infection caused by the d-tartrate-fermenting variant of salmonella enterica serovar paratyphi b [s. paratyphi b (dt+)] was investigated. in germany, the serovar is frequently isolated from broilers. therefore, a selection of 108 epidemiologically unrelated s. enterica serovar paratyphi b (dt+) strains isolated in germany between 2002 and 2010 especially from humans, poultry/poultry meat, and reptiles was investig ...201222885742
emergence of fluoroquinolone resistance in salmonella enterica serovar typhi in andaman and nicobar islands, india. 201222885270
genome-wide detection of spontaneous chromosomal rearrangements in bacteria.genome rearrangements have important effects on bacterial phenotypes and influence the evolution of bacterial genomes. conventional strategies for characterizing rearrangements in bacterial genomes rely on comparisons of sequenced genomes from related species. however, the spectra of spontaneous rearrangements in supposedly homogenous and clonal bacterial populations are still poorly characterized. here we used 454 pyrosequencing technology and a 'split mapping' computational method to identify ...201222880062
characterization of extended-spectrum beta-lactamase-producing salmonella enterica serotype brunei and heidelberg at the hussein dey hospital in algiers (algeria).the purpose of this work was to study the genetic determinants responsible for extended-spectrum cephalosporin (esc) resistance of salmonella collected during the period of 1995-2008 at the hussein dey hospital in algiers (algeria). fourteen esc-resistant salmonella isolates were tested towards 22 antimicrobial agents. polymerase chain reaction (pcr) and sequencing were used to determine the underlying genetic determinants responsible for the extended-spectrum beta-lactamase (esbl) phenotypes. e ...201222871227
farm-level associations with the shedding of salmonella and antimicrobial-resistant salmonella in u.s. dairy cattle.salmonella enterica is the leading cause of foodborne-related deaths and hospitalizations within the united states. infections caused by antimicrobial-resistant (amr) strains are associated with higher hospital costs and case fatality. the objective for this study was to determine the association of management practices with the recovery of salmonella and amr salmonella on dairy herds. individual adult cow fecal samples and/or composite fecal samples were collected from 265 dairy herds in 17 sta ...201222870913
multiple pathways of duplication formation with and without recombination (reca) in salmonella enterica.duplications are often attributed to "unequal recombination" between separated, directly repeated sequence elements (>100 bp), events that leave a recombinant element at the duplication junction. however, in the bacterial chromosome, duplications form at high rates (10(-3)-10(-5)/cell/division) even without recombination (reca). here we describe 1800 spontaneous lac duplications trapped nonselectively on the low-copy f'(128) plasmid, where lac is flanked by direct repeats of the transposable ele ...201222865732
cross-reactive gut-directed immune response against salmonella enterica serovar paratyphi a and b in typhoid fever and after oral ty21a typhoid vaccination.there are no vaccines against paratyphoid fever in clinical use. the disease has become more wide-spread and there is a growing problem of antibiotic resistance among the strains. previous reports suggest that the oral live salmonella typhi ty21a-vaccine confers protection against paratyphoid b fever. data on efficacy against paratyphoid a fever are somewhat contentious. the present study investigated the immunological basis for such efficacy reports at a single-cell level: plasmablasts (identif ...201222858557
refractory salmonella enterica serotype choleraesuis-related renal cyst infection in a patient with autosomal dominant polycystic kidney disease undergoing hemodialysis treated successfully with intracystic ciprofloxacin infusion.to report a potential salvage therapy for refractory renal cyst infection secondary to salmonellaenterica serotype choleraesuis (s. choleraesuis).201222710499
association of extended-spectrum β-lactamase veb-5 and 16s rrna methyltransferase arma in salmonella enterica from the united kingdom. 201222710120
salmonellosis outbreak traced to playground sand, australia, 2007-2009.a community outbreak of gastroenteritis in australia during 2007-2009 was caused by ingestion of playground sand contaminated with salmonella enterica paratyphi b, variant java. the bacterium was also isolated from local wildlife. findings support consideration of nonfood sources during salmonellosis outbreak investigations and indicate transmission through the animal-human interface.201222709539
emergence of an sgi1-bearing salmonella enterica serotype kentucky isolated from septic poultry in nigeria.salmonella enterica serotype kentucky was isolated from septic poultry in nigeria. the objective of this study was to characterize this isolate by screening for sgi1 and hyper-virulence.201222706190
the feoa protein is necessary for the feob transporter to import ferrous iron.in many bacterial feo loci, the feoa gene is associated with the feob gene. while the feob-encoded feob protein has been demonstrated as a ferrous iron [fe(ii)] transporter, the function of the feoa gene product, feoa, is unknown. in the present study, we report that the feoa protein interacts with the feob fe(ii) transporter, which is required for feob-mediated fe(ii) uptake in salmonella enterica. iron uptake assay revealed that in the absence of feoa, feob import of fe(ii) is impaired. bacter ...201222705302
assessment of pathogen survival potential during managed aquifer recharge with diffusion chambers.to evaluate the efficacy of using in situ diffusion chambers for pathogen decay studies in the aquifer.201222702409
control of a salmonella virulence locus by an atp-sensing leader messenger rna.the facultative intracellular pathogen salmonella enterica resides within a membrane-bound compartment inside macrophages. this compartment must be acidified for salmonella to survive within macrophages, possibly because acidic ph promotes expression of salmonella virulence proteins. we reasoned that salmonella might sense its surroundings have turned acidic not only upon protonation of the extracytoplasmic domain of a protein sensor but also by an increase in cytosolic atp levels, because condi ...201222699622
characterization of the salmonella bacteriophage vb_sens-ent1.the bacteriophage vb_sens-ent1 (ent1) is a member of the family siphoviridae of tailed bacteriophages and infects a broad range of serovars of the enteric pathogen salmonella enterica. the virion particle is composed of an icosahedral head 64 nm in diameter and a flexible, non-contractile tail of 116 × 8.5 nm possessing terminal fibres. the adsorption rate constant at 37 °c is 6.73 × 10(-9) ml min(-1). latent and eclipse periods are 25 and 20 min, respectively, and the burst size is 35 progeny p ...201222694898
genetic fine structure of a salmonella enterica serovar typhi strain associated with the 2005 outbreak of typhoid fever in kelantan, malaysia.among enteric pathogens, salmonella enterica serovar typhi is responsible for the largest number of food-borne outbreaks and fatalities. the ability of the pathogen to cause systemic infection for extended durations leads to a high cost of disease control. chronic carriers play important roles in the evolution of salmonella typhi; therefore, identification and in-depth characterization of isolates from clinical cases and carriers, especially those from zones of endemicity where the pathogen has ...201222689247
complete genome sequence of the strong mutator salmonella enterica subsp. enterica serotype heidelberg strain b182.in bacteria, normal mutation frequencies are mostly around 10(-10) per base pair. however, there exists natural isolates, called "mutators," that exhibit permanent mutation occurrences up to 1,000-fold greater than usual. as mutations play essential roles, particularly in the evolution of antibiotic resistance, bacteria showing elevated mutation rates could have an important responsibility in the emergence of antibiotic resistance, especially in the clinical background. in this announcement, we ...201222689230
evolution of salmonella enterica virulence via point mutations in the fimbrial adhesin.whereas the majority of pathogenic salmonella serovars are capable of infecting many different animal species, typically producing a self-limited gastroenteritis, serovars with narrow host-specificity exhibit increased virulence and their infections frequently result in fatal systemic diseases. in our study, a genetic and functional analysis of the mannose-specific type 1 fimbrial adhesin fimh from a variety of serovars of salmonella enterica revealed that specific mutant variants of fimh are co ...201222685400
heterogeneity of multifunctional il-17a producing s. typhi-specific cd8+ t cells in volunteers following ty21a typhoid immunization.salmonella enterica serovar typhi (s. typhi), the causative agent of typhoid fever, continues to cause significant morbidity and mortality world-wide. cd8+ t cells are an important component of the cell mediated immune (cmi) response against s. typhi. recently, interleukin (il)-17a has been shown to contribute to mucosal immunity and protection against intracellular pathogens. to investigate multifunctional il-17a responses against s. typhi antigens in t memory subsets, we developed multiparamet ...201222679502
a positive selection approach identifies residues important for folding of salmonella enterica pat, an n(ε)-lysine acetyltransferase that regulates central metabolism enzymes.in salmonella enterica, the protein acetyltransferase (pat) enzyme is part of the sirtuin-dependent acylation/deacylation system (sdpads) that modulates the activity of several proteins via the acylation of lysine residues critical to their activities. pat is a ~98 kda protein with two distinct domains, an n-terminal acyl-coa synthetase (ndp-forming) domain (~700 aa) and a c-terminal acetyltransferase domain (~160 aa), with homology to proteins of the gcn5-related n-acetyltransferase (gnat) supe ...201222677774
emergence of salmonella enterica serovar infantis harboring inci1 plasmid with bla(ctx-m-14) in a broiler farm in japan.cefotaxime (ctx)-resistant and -susceptible salmonella enterica serovar infantis isolates obtained from broilers raised on a farm in january 2010 in japan were characterized to establish their resistance determinants. the ctx-resistant isolates produced ctx-m-14 extended-spectrum β-lactamase and harbored 2 distinct plasmid of approximately 140- and 95-kb, whereas the ctx-susceptible isolates harbored one 140-kb plasmid. the 95-kb plasmids were replicon typed as inci1 carrying the bla(ctx-m-14) g ...201222673563
molecular typing and resistance analysis of travel-associated salmonella enterica serotype typhi.salmonella enterica serotype typhi is a human pathogen causing 12 to 30% mortality and requiring antibiotic therapy to control the severity of the infection. typhoid fever in united states is often associated with foreign travel to areas of endemicity. increasing resistance to multiple drugs, including quinolones, is associated with decreased susceptibility to ciprofloxacin (dcs). we investigated 31 clinical strains isolated in florida from 2007 to 2010, associated with travel to six countries, ...201222649021
genome sequences of five salmonella enterica serovar heidelberg isolates associated with a 2011 multistate outbreak in the united states.salmonella enterica serovar heidelberg has caused numerous outbreaks in humans. here, we report draft genomes of five isolates of serovar heidelberg associated with the recent (2011) multistate outbreak linked to ground turkey in the united states. isolates 2011k-1110 and 2011k-1132 were recovered from humans, while isolates 2011k-1138, 2011k-1224, and 2011k-1225 were recovered from ground turkey. whole-genome sequence analysis of these isolates provides a tool for studying the short-term evolut ...201222628505
antibiotic susceptibility pattern and the indicator of decreased ciprofloxacin susceptibility of salmonella enterica serovar typhi isolated from dhulikhel hospital, nepal.monitoring the antibiotic susceptibility pattern of salmonella enterica serovar typhi (s. typhi) is important for efficiently managing cases of typhoid fever. in this study, the antimicrobial susceptibility patterns of 114 s. typhi isolates, which were collected from a university hospital in nepal during july 2009-december 2010, were investigated by disc diffusion assays. all of the s. typhi isolates were sensitive to amoxycillin-clavulanic acid. more than 95% of the isolates were sensitive to c ...201222627312
antibiotic resistant salmonella and vibrio associated with farmed litopenaeus vannamei.salmonella and vibrio species were isolated and identified from litopenaeus vannamei cultured in shrimp farms. shrimp samples showed occurrence of 3.3% of salmonella and 48.3% of vibrio. the isolates were also screened for antibiotic resistance to oxolinic acid, sulphonamides, tetracycline, sulfamethoxazole/trimethoprim, norfloxacin, ampicillin, doxycycline hydrochloride, erythromycin, chloramphenicol, and nitrofurantoin. salmonella enterica serovar corvallis isolated from shrimp showed individu ...201222619583
salmonella strains isolated from galápagos iguanas show spatial structuring of serovar and genomic diversity.it is thought that dispersal limitation primarily structures host-associated bacterial populations because host distributions inherently limit transmission opportunities. however, enteric bacteria may disperse great distances during food-borne outbreaks. it is unclear if such rapid long-distance dispersal events happen regularly in natural systems or if these events represent an anthropogenic exception. we characterized salmonella enterica isolates from the feces of free-living galápagos land an ...201222615968
a maximum likelihood qtl analysis reveals common genome regions controlling resistance to salmonella colonization and carrier-state.the serovars enteritidis and typhimurium of the gram-negative bacterium salmonella enterica are significant causes of human food poisoning. fowl carrying these bacteria often show no clinical disease, with detection only established post-mortem. increased resistance to the carrier state in commercial poultry could be a way to improve food safety by reducing the spread of these bacteria in poultry flocks. previous studies identified qtls for both resistance to carrier state and resistance to salm ...201222613937
plasmid-mediated quinolone resistance determinant qnrb19 in non-typhoidal salmonella enterica strains isolated in venezuela. 201222610715
a retrospective study of community-acquired salmonella infections in patients attending public hospitals in lagos, nigeria.a retrospective cohort study on salmonella-associated diseases (sads) was conducted in 14 public hospitals across lagos state, nigeria, between 1999 and 2008.201222610704
influence of serotype on the growth kinetics and the ability to form biofilms of salmonella isolates from poultry.the influence of the serotype on the growth behaviour and the ability to form biofilms of salmonella enterica strains was investigated. the relationships between biofilm formation and growth kinetic parameters were also determined. a total of 69 strains (61 isolates from poultry and 8 reference strains from culture collections) belonging to 10 serotypes (s. enterica serotype typhimurium, s. newport, s. paratyphi b, s. poona, s. derby, s. infantis, s. enteritidis, s. virchow, s. agona and s. typh ...201222608221
salmonella cross-contamination in swine abattoirs in portugal: carcasses, meat and meat handlers.in this study the occurrence of salmonella in swine, pork meat and meat handlers along with their clonal relatedness is evaluated at abattoir level. samples from the lymph nodes, carcass surface and meat of 100 pigs and 45 meat handlers were collected in eight abattoirs (july 2007-august 2008). salmonella isolates were serotyped and genotyped by pulsed-field gel electrophoresis (pfge). from the pigs tested, 42 produced at least one positive sample. a relatively high frequency of salmonella occur ...201222607810
first outbreak of food poisoning caused by salmonella enterica subspecies enterica serovar berta in italy.to provide an epidemiologic interpretation of a suspected outbreak of food poisoning caused by salmonella enterica subspecies enterica serovar berta strains isolated from humans and from the leftovers of the implicated foods (cream, dairy-based desserts and eggs).201222607387
a gold nanoparticles based immuno-bioprobe for detection of vi capsular polysaccharide of salmonella enterica serovar typhi.a rapid and sensitive gold-nanobioprobe based immunoassay format has been presented for the detection of capsular vi polysaccharide of salmonella enterica serovar typhi (surface antigen) using anti-vi antibodies. the vi antigen was extracted from serovar typhi cells, under the optimised growth conditions for its over-expression. anti-vi antibodies were produced and conjugated with gold nanoparticles (gnps) of definite size (~30 nm), which served as the nano-bioprobe in the detection system. a sa ...201222592180
shedding light on salmonella carriers.host-to-host transmission in most salmonella serovars occurs primarily via the fecal-oral route. salmonella enterica serovar typhi is a human host-adapted pathogen and some s. typhi patients become asymptomatic carriers. these individuals excrete large numbers of the bacteria in their feces and transmit the pathogen by contaminating water or food sources. the carrier state has also been described in livestock animals and is responsible for food-borne epidemics. identification and treatment of ca ...201222591832
salmonella enterica serotype enteritidis: increasing incidence of domestically acquired infections.salmonella enterica causes an estimated 1 million cases of domestically acquired foodborne illness in humans annually in the united states; enteritidis (se) is the most common serotype. public health authorities, regulatory agencies, food producers, and food processors need accurate information about rates and changes in se infection to implement and evaluate evidence-based control policies and practices.201222572674
application of the random forest method to analyse epidemiological and phenotypic characteristics of salmonella 4,[5],12:i:- and salmonella typhimurium strains.salmonella enterica 4,[5],12:i:- is a monophasic variant of s. typhimurium. in the last decade, its prevalence rose sharply. although s. 4,[5],12:i:- and s. typhimurium are known to pose a considerable public health risk, there is no detailed information on the circulation of these serovars in italy, particularly as far as veterinary isolates are concerned. for this reason, a data set of 877 strains isolated in the north-east of italy from foodstuffs, animals and environment was analysed during ...201222583909
selection of salmonella enterica serovar typhi genes involved during interaction with human macrophages by screening of a transposon mutant library.the human-adapted salmonella enterica serovar typhi (s. typhi) causes a systemic infection known as typhoid fever. this disease relies on the ability of the bacterium to survive within macrophages. in order to identify genes involved during interaction with macrophages, a pool of approximately 10(5) transposon mutants of s. typhi was subjected to three serial passages of 24 hours through human macrophages. mutants recovered from infected macrophages (output) were compared to the initial pool (in ...201222574205
chronic proliferative rhinitis associated with salmonella enterica subspecies diarizonae serovar 61:k:1, 5, (7) in sheep in spain.a chronic proliferative rhinitis in sheep associated with salmonella enterica subspecies diarizonae serovar 61:k:1, 5, (7) is described. ten adult sheep from eight traditionally managed rasa aragonesa flocks located in aragon (spain) were studied. clinical signs began with bilateral thick mucus nasal discharge, wheezing and snoring and progressed to partial or complete obstruction of the nostrils. necropsy examination revealed swollen ventral nasal turbinates with a roughened mucosal surface par ...201222572396
salmonella enterica serovar typhi plasmid impairs dendritic cell responses to infection.salmonella enterica serovar typhi (s. typhi) evades from innate immunity by expression of a variety of pathogenic factors. the "pr(st98)" plasmid of s. typhi is involved in multidrug-resistant and virulence of s. typhi. however, its exact effect on host cell function remains elusive. dendritic cells (dcs) play an important role in shaping immune response against salmonella. for the purpose of investigation whether pr(st98) might target dcs involved in adaptive immune response, murine dcs were in ...201222569891
frequency and antimicrobial resistance of salmonella serotypes on beef carcasses at small abattoirs in jalisco state, mexico.the prevalence and antimicrobial resistance of salmonella serotypes on beef carcasses from four small abattoirs in jalisco state, mexico, were investigated during a 10-month period. following u.s. department of agriculture food safety and inspection service protocols, salmonella was isolated from 78 (15.4%) beef carcasses (n = 505) after the final carcass water wash. isolation frequency differed by establishment (p < 0.05) and was higher (p < 0.05) during the wet season (may through september) f ...201222564935
microbiological analysis of bovine lymph nodes for the detection of salmonella enterica.bovine peripheral lymph nodes (lns) have been identified as a potential source of salmonella when trim containing these nodes is incorporated into ground beef. studies examining the prevalence of salmonella in peripheral lns of cattle are few in number, and the microbiological methods used for these analyses have not been validated. given that salmonella contamination may be found on postintervention carcasses, it is important to understand the extent to which salmonella contamination from surro ...201222564933
virulence of 32 salmonella strains in mice.virulence and persistence in the balb/c mouse gut was tested for 32 strains of salmonella enterica for which genome sequencing is complete or underway, including 17 serovars within subspecies i (enterica), and two representatives of each of the other five subspecies. only serovar paratyphi c strain baa1715 and serovar typhimurium strain 14028 were fully virulent in mice. three divergent atypical enteritidis strains were not virulent in balb/c, but two efficiently persisted. most of the other str ...201222558320
prevalence and characterization of motile salmonella in commercial layer poultry farms in bangladesh.salmonella is a globally widespread food-borne pathogen having major impact on public health. all motile serovars of salmonella enterica of poultry origin are zoonotic, and contaminated meat and raw eggs are an important source to human infections. information on the prevalence of salmonella at farm/holding level, and the zoonotic serovars circulating in layer poultry in the south and south-east asian countries including bangladesh, where small-scale commercial farms are predominant, is limited. ...201222558269
complete nucleotide sequence of pvqs1 containing a quinolone resistance determinant from salmonella enterica serovar virchow associated with foreign travel.nalidixic acid-resistant salmonella enterica serovars kentucky (n = 5) and virchow (n = 6) cultured from individuals were investigated for the presence of plasmid-mediated quinolone resistance (pmqr) determinants.201222553140
dynamics of salmonella infection of macrophages at the single cell level.salmonella enterica causes a range of diseases. salmonellae are intracellular parasites of macrophages, and the control of bacteria within these cells is critical to surviving an infection. the dynamics of the bacteria invading, surviving, proliferating in and killing macrophages are central to disease pathogenesis. fundamentally important parameters, however, such as the cellular infection rate, have not previously been calculated. we used two independent approaches to calculate the macrophage ...201222552918
identification of genes responsible for biofilm formation or virulence in salmonella enterica serovar pullorum.salmonella living in biofilms are more resistant to chemical and physical stresses. however, information regarding the regulation of genes involved in biofilm formation for salmonella enterica serovar pullorum remains limited. in this study, eight mutants with knockout of genes ompr, rpos, rfag, rfbh, rhle, mete, spia, or steb from the salmonella enterica serovar pullorum strain s6702 were constructed. phenotypic analysis revealed that all mutants were similar to the wild-type strain in growth r ...201222545539
heterogeneity of persistence of salmonella enterica serotype senftenberg strains could explain the emergence of this serotype in poultry flocks.salmonella enterica serotype senftenberg (s. senftenberg) has recently become more frequent in poultry flocks. moreover some strains have been implicated in severe clinical cases. to explain the causes of this emergence in farm animals, 134 s. senftenberg isolates from hatcheries, poultry farms and human clinical cases were analyzed. persistent and non-persistent strains were identified in chicks. the non-persistent strains disappeared from ceca a few weeks post inoculation. this lack of persist ...201222545136
high pressure inactivation of salmonella on jalapeño and serrano peppers destined for direct consumption or as ingredients in mexican salsa and guacamole.in summer of 2008, the united states witnessed one of the largest multi-state salmonellosis outbreak linked to the consumption of jalapeño and serrano peppers tainted with salmonella enterica serovar saintpaul. the first objective of this study was to assess the application of high hydrostatic pressure (hhp) to decontaminate jalapeño and serrano peppers from this pathogen. jalapeño and serrano peppers were inoculated with a five-strain cocktail of salmonella to a final level of ca. ~6 log cfu/g ...201222534353
distribution of salmonella serovars and antimicrobial susceptibility of salmonella enteritidis from poultry in zimbabwe.a study was carried out to determine the distribution and antimicrobial susceptibility profiles of salmonella serovars from chickens from large-scale commercial (lsc), small-scale commercial (ssc), and rural free-range (rfr) farms of zimbabwe. pooled cloacal swabs were collected for culture and isolation of salmonella spp. a chi-square test was used to assess distribution differences of salmonellas among the farming sectors. approximately 10% (283/2833) of the swabs were positive for salmonella ...201222515540
the extradomain a of fibronectin enhances the efficacy of lipopolysaccharide defective salmonella bacterins as vaccines in mice.the extradomain a from fibronectin (eda) has an immunomodulatory role as fusion protein with viral and tumor antigens, but its effect when administered with bacteria has not been assessed. here, we investigated the adjuvant effect of eda in mice immunizations against salmonella enterica subspecies enterica serovar enteritidis (salmonella enteritidis). since lipopolysaccharide (lps) is a major virulence factor and the lps o-polysaccharide (o-ps) is the immunodominant antigen in serological diagno ...201222515195
increased resistance to multiple antimicrobials and altered resistance gene expression in cmy-2-positive salmonella enterica following a simulated patient treatment with ceftriaxone.salmonellosis is one of the most common causes of food-borne disease in the united states. increasing antimicrobial resistance and corresponding increases in virulence present serious challenges. currently, empirical therapy for invasive salmonella enterica infection includes either ceftriaxone or ciprofloxacin (e. l. hohmann, clin. infect. dis. 32:263-269, 2001). the bla(cmy-2) gene confers resistance to ceftriaxone, the antimicrobial of choice for pediatric patients with invasive salmonella en ...201222961898
a novel salmonella serovar isolated from peregrine falcon (falco peregrinus) nestlings in sweden: salmonella enterica enterica serovar pajala (salmonella pajala).a novel salmonella serovar was isolated from peregrine falcon (falco peregrinus) nestlings in northern sweden in 2006. three isolates of the same clone was retrieved from three falcon siblings and characterized as salmonella enterica sub-species enterica: o-phase 13, 23:-: e, n, z 15 and the h-phase was not present. we propose the geographical name salmonella enterica, sub-species enterica serovar pajala to this novel salmonella.201222957136
prevalence of salmonella cerro in laboratory-based submissions of cattle and comparison with human infections in pennsylvania, 2005-2010.the aim of this study was to identify salmonella serotypes infecting cattle in pennsylvania, to compare infection rates for the predominant serotype, salmonella enterica serotype cerro, with the infection rates for the same serotype in humans, and to study the clonal diversity and antimicrobial resistance for this serotype in cattle from 2005 to 2010. clonal diversity among the selected isolates was studied using pulsed-field gel electrophoresis (pfge) and repetitive (rep)-polymerase chain react ...201222953739
longitudinal dissemination of salmonella enterica clonal groups through the slaughter process of salmonella-positive pig batches.this study was conducted to assess the dissemination of salmonella clonal groups in slaughterhouses that received batches of salmonella -positive pigs and used different routine processing procedures. eight serial sampling sessions were conducted in three slaughterhouses (a, b, and c). blood was collected randomly (n = 25) from each batch of pigs and processed for serology. carcasses (n = 12) were identified and sampled after dehairing, after singeing, after evisceration, and before chilling. a ...201222947464
increasing quinolone resistance and multidrug resistant isolates among salmonella enterica in hong kong.to study the antimicrobial susceptibility and molecular epidemiology of salmonella enterica isolates from 2005 to 2010 in hong kong.201222947244
comparative proteome and transcriptome analyses of wild-type and live vaccine strains of salmonella enterica serovar gallinarum.salmonella enterica serovar gallinarum causes fowl typhoid in chickens and is of economic importance to the chicken industry. a serovar gallinarum live vaccine strain 9r (sg 9r) has been used to control fowl typhoid in many areas where the disease is endemic. because the attenuation mechanism of sg 9r was not defined, there has been continued concern about reversion to virulence. in this study, we examined the molecular characteristics, which might provide better insight into attenuation of sg 9 ...201222944630
draft genome sequences of eight salmonella enterica serotype newport strains from diverse hosts and locations.salmonellosis is a major contributor to the global public health burden. salmonella enterica serotype newport has ranked among three salmonella serotypes most commonly associated with food-borne outbreaks in the united states. it was thought to be polyphyletic and composed of independent lineages. here we report draft genomes of eight strains of s. newport from diverse hosts and locations.201222933769
insights from the genome sequence of a salmonella enterica serovar typhi strain associated with a sporadic case of typhoid fever in malaysia.salmonella enterica serovar typhi is the causative agent of typhoid fever, which causes nearly 21.7 million illnesses and 217,000 deaths globally. herein, we describe the whole-genome sequence of the salmonella typhi strain st0208, isolated from a sporadic case of typhoid fever in kuala lumpur, malaysia. the whole-genome sequence and comparative genomics allow an in-depth understanding of the genetic diversity, and its link to pathogenicity and evolutionary dynamics, of this highly clonal pathog ...201222933756
whole-genome sequences and comparative genomics of salmonella enterica serovar typhi isolates from patients with fatal and nonfatal typhoid fever in papua new guinea.many of the developing countries of the southeast asian region are significantly affected by endemic typhoid fever, possibly as a result of marginal living standards. it is an important public health problem in countries such as papua new guinea, which is geographically close to some of the foci of endemicity in asia. the severity of the disease varies in different regions, and this may be attributable to genetic diversity among the native strains. genome sequence data on strains from different ...201222933755
salmonella enterica serovar agbeni, british columbia, canada, 2011. 201222932699
interactions between the termini of lumen enzymes and shell proteins mediate enzyme encapsulation into bacterial microcompartments.bacterial microcompartments (mcps) are a widespread family of proteinaceous organelles that consist of metabolic enzymes encapsulated within a protein shell. for mcps to function specific enzymes must be encapsulated. we recently reported that a short n-terminal targeting sequence of propionaldehyde dehydrogenase (pdup) is necessary and sufficient for the packaging of enzymes into a mcp that functions in 1,2-propanediol (1,2-pd) utilization (pdu) by salmonella enterica. here we show that encapsu ...201222927404
salmonella can reach tomato fruits on plants exposed to aerosols formed by rain.outbreaks of salmonella enterica have been associated with tomatoes and traced back to production areas but the spread of salmonella in agricultural fields is still poorly understood. post-rain salmonella transfer from a point source to the air and then to tomato plants was evaluated. gfp-labeled kanamycin-resistant s. enterica serovar typhimurium (10(8)cfu/ml) with and without expression of the rdar morphotype (rough colonies; cells with fimbriae and cellulose) was used as the point source in t ...201222831820
vaccines for typhoid fever and other salmonelloses.this review summarizes the recent advances in vaccination against salmonella enterica serovar typhi and highlights the data supporting the development of next generation vaccines to address paratyphoid fever and invasive nontyphoidal salmonella (ints) disease.201222825288
assessment of root uptake and systemic vine-transport of salmonella enterica sv. typhimurium by melon (cucumis melo) during field production.among melons, cantaloupes are most frequently implicated in outbreaks and surveillance-based recalls due to salmonella enterica. there is limited but compelling evidence that associates irrigation water quality as a significant risk of preharvest contamination of melons. however, the potential for root uptake from water and soil and subsequent systemic transport of salmonella into melon fruit is uncharacterized. the aim of this work was to determine whether root uptake of s. enterica results in ...201222824339
salmonella enterica serovar ohio septic arthritis and bone abscess in an immunocompetent patient: a case report.non-typhi salmonella species cause severe extra-intestinal focal infection after occult bacteremia. although the number of cases of non-typhi salmonellosis is increasing worldwide among patients with immunocompromising conditions such as human immunodeficiency virus infection, infection is uncommon in immunocompetent subjects. we report a case of septic arthritis and bone abscess due to a rare non-typhi salmonella organism that developed after a prolonged asymptomatic period.201222804866
characterization of osmotically induced filaments of salmonella enterica.salmonella enterica forms aseptate filaments with multiple nucleoids when cultured in hyperosmotic conditions. these osmotic-induced filaments are viable and form single colonies on agar plates even though they contain multiple genomes and have the potential to divide into multiple daughter cells. introducing filaments that are formed during osmotic stress into culture conditions without additional humectants results in the formation of septa and their division into individual cells, which could ...201222798362
a new methodology for differentiation and typing of closely related salmonella enterica serovar heidelberg isolates.this study describe the use of a combination of two recently proposed typing approaches, multiple amplification of prophage locus typing (maplt) and multiple-locus variable-number tandem-repeat analysis (mlva) for subdividing within salmonella enterica serovar heidelberg (s. heidelberg). the combined typing method was compared with pulsed-field gel electrophoresis (pfge) by simpson's index of diversity (di). pfge was shown to have a di = 0.84 and was poor at differentiation of the predominant pt ...201222797864
drug resistance in salmonella enterica serotype typhi isolated from chronic typhoid carriers. 201222789724
panm, an acetyl-coenzyme a sensor required for maturation of l-aspartate decarboxylase (pand).coenzyme a (coa) is essential for cellular chemistry in all forms of life. the pantothenate moiety of coa is generated from the condensation of pantoate and β-alanine. β-alanine is formed by decarboxylation of l-aspartate catalyzed by pand, a pyruvoyl enzyme that is synthesized by the cell as an inactive precursor (pro-pand). maturation of pro-pand into pand occurs via a self-cleavage event at residue ser25, which forms the catalytic pyruvoyl moiety. we recently reported that salmonella enterica ...201222782525
selection-driven gene loss in bacteria.gene loss by deletion is a common evolutionary process in bacteria, as exemplified by bacteria with small genomes that have evolved from bacteria with larger genomes by reductive processes. the driving force(s) for genome reduction remains unclear, and here we examined the hypothesis that gene loss is selected because carriage of superfluous genes confers a fitness cost to the bacterium. in the bacterium salmonella enterica, we measured deletion rates at 11 chromosomal positions and the fitness ...201222761588
molecular characterization of salmonella strains in individuals with acute diarrhea syndrome in the state of sucre, venezuela.in venezuela, acute diarrheic syndrome (ads) is a primary cause of morbi-mortality, often involving the salmonella genus. salmonella infections are associated with acute gastroenteritis, one of the most common alimentary intoxications, and caused by the consumption of contaminated water and food, especially meat.201222760131
characterization of extended-spectrum cephalosporin-resistant salmonella enterica serovar heidelberg isolated from food animals, retail meat, and humans in the united states 2009.salmonella enterica is one of the most common causes of foodborne illness in the united states. although salmonellosis is usually self-limiting, severe infections typically require antimicrobial treatment, and ceftriaxone, an extended-spectrum cephalosporin (esc), is commonly used in both adults and children. surveillance conducted by the national antimicrobial resistance monitoring system (narms) has shown a recent increase in esc resistance among salmonella heidelberg isolated from food animal ...201222755514
in vitro susceptibility testing of fluoroquinolone activity against salmonella: recent changes to clsi standards.fluoroquinolone (fq) resistance in salmonella enterica is a significant clinical concern. recognition of resistance by the clinical laboratory is complicated by the multiple fq resistance mechanisms found in salmonella. the clinical laboratory standards institute (clsi) recently addressed this issue by revising the ciprofloxacin break points for salmonella species. it is critical for clinicians and laboratory workers to be aware of the multiple technical issues surrounding these revised break po ...201222752519
the wzx translocases for salmonella enterica o-antigen processing have unexpected serotype specificity.most gram-negative bacteria have an o antigen, a polysaccharide with many repeats of a short oligosaccharide that is a part of the lipopolysaccharide, the major lipid in the outer leaflet of the outer membrane. lipopolysaccharide is variable with 46 forms in salmonella enterica that underpin the serotyping scheme. repeat units are assembled on a lipid carrier that is embedded in the cell membrane, and are then translocated by the wzx translocase from the cytoplasmic face to the outer face of the ...201222497246
chronic infection drives expression of the inhibitory receptor cd200r, and its ligand cd200, by mouse and human cd4 t cells.certain parasites have evolved to evade the immune response and establish chronic infections that may persist for many years. t cell responses in these conditions become muted despite ongoing infection. upregulation of surface receptors with inhibitory properties provides an immune cell-intrinsic mechanism that, under conditions of chronic infection, regulates immune responses and limits cellular activation and associated pathology. the negative regulator, cd200 receptor, and its ligand, cd200, ...201222496920
selective enrichment media bias the types of salmonella enterica strains isolated from mixed strain cultures and complex enrichment broths.for foodborne outbreak investigations it can be difficult to isolate the relevant strain from food and/or environmental sources. if the sample is contaminated by more than one strain of the pathogen the relevant strain might be missed. in this study mixed cultures of salmonella enterica were grown in one set of standard enrichment media to see if culture bias patterns emerged. nineteen strains representing four serogroups and ten serotypes were compared in four-strain mixtures in salmonella-only ...201222496847
salmonella transiently reside in luminal neutrophils in the inflamed gut.enteric pathogens need to grow efficiently in the gut lumen in order to cause disease and ensure transmission. the interior of the gut forms a complex environment comprising the mucosal surface area and the inner gut lumen with epithelial cell debris and food particles. recruitment of neutrophils to the intestinal lumen is a hallmark of non-typhoidal salmonella enterica infections in humans. here, we analyzed the interaction of gut luminal neutrophils with s. enterica serovar typhimurium (s. tm) ...201222493718
use of urine with nested pcr targeting the flagellin gene (flic) for diagnosis of typhoid fever.this study was planned to evaluate the efficacy of the use of nested pcr with a large volume of easily available urine as an effort to devise a test that can meet the levels necessary to be considered a gold standard for the diagnosis of typhoid fever. a total of 60 subjects with suspected cases of typhoid fever and 20 apparently healthy control subjects were included in the study. the study period extended from march 2010 to june 2011. blood, urine, and stool specimens were collected from the p ...201222493333
genome sequence of the invasive salmonella enterica subsp. enterica serotype enteritidis strain la5.salmonella enterica subsp. enterica serotype enteritidis is one of the major causes of gastroenteritis in humans due to consumption of poultry derivatives. here we report the whole-genome sequence and annotation, including the virulence plasmid, of s. enteritidis la5, which is a chicken isolate used by numerous laboratories in virulence studies.201222493198
genome sequence of the persistent salmonella enterica subsp. enterica serotype senftenberg strain ss209.salmonella enterica subsp. enterica serotype senftenberg is an emerging serotype in poultry production which has been found to persist in animals and the farm environment. we report the genome sequence and annotation of the ss209 strain of s. senftenberg, isolated from a hatchery, which was identified as persistent in broiler chickens.201222493197
live oral typhoid vaccine ty21a induces cross-reactive humoral immune responses against salmonella enterica serovar paratyphi a and s. paratyphi b in humans.enteric fever caused by salmonella enterica serovar paratyphi a infection has emerged as an important public health problem. recognizing that in randomized controlled field trials oral immunization with attenuated s. enterica serovar typhi live vaccine ty21a conferred significant cross-protection against s. paratyphi b but not s. paratyphi a disease, we undertook a clinical study to ascertain whether humoral immune responses could explain the field trial results. ty21a immunization of adult resi ...201222492745
comparison of a real-time pcr method with a culture method for the detection of salmonella enterica serotype enteritidis in naturally contaminated environmental samples from integrated poultry houses.conventional culture methods have traditionally been considered the "gold standard" for the isolation and identification of foodborne bacterial pathogens. however, culture methods are labor-intensive and time-consuming. a salmonella enterica serotype enteritidis-specific real-time pcr assay that recently received interim approval by the national poultry improvement plan for the detection of salmonella enteritidis was evaluated against a culture method that had also received interim national poul ...201222488064
prevalence and antimicrobial susceptibility of salmonella isolated from a variety of raw meat sausages in gaborone (botswana) retail stores.the objective of the study was to provide baseline data on the prevalence and antimicrobial susceptibility of salmonella in different types of raw meat sausages directly accessible to the consumers in gaborone, botswana. a total of 300 raw sausages comprising 79 beef, 78 pork, 72 chicken, and 71 mutton samples were concurrently analyzed for the presence of salmonella using a conventional culture method and a validated pcr method. the pcr assay results were in full concordance with those of the c ...201222488050
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