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an outbreak of multidrug-resistant salmonella enterica serotype oranienburg in michigan dairy calves.the objectives of this study were to report an outbreak of highly drug-resistant salmonella enterica serotype oranienburg in dairy calves, and conduct an epidemiological investigation of oranienburg identified on a dairy herd during a study to determine whether discontinuing feeding medicated milk replacer to preweaned dairy calves resulted in increased antimicrobial susceptibility in enteric bacteria. calf fecal samples and swabs of calf and maternity pens were collected monthly over 18 months. ...201020939741
flio regulation of flip in the formation of the salmonella enterica flagellum.the type iii secretion system of the salmonella flagellum consists of 6 integral membrane proteins: flha, flhb, flio, flip, fliq, and flir. however, in some other type iii secretion systems, a homologue of flio is apparently absent, suggesting it has a specialized role. deleting the flio gene from the chromosome of a motile strain of salmonella resulted in a drastic decrease of motility. incubation of the δflio mutant strain in motility agar, gave rise to pseudorevertants containing extragenic b ...201020941389
genetic evolution of the spanish multidrug-resistant salmonella enterica 4,5,12:i:- monophasic variant.we analyzed a collection of 60 salmonella enterica 4,5,12:i:- phage type u302 multidrug-resistant monophasic variant strains, isolated in spain between 2000 and 2007. most strains showed resistance to ampicillin (a), chloramphenicol (c), sulfamethoxazole (su), gentamicin (g), streptomycin (s), tetracycline (t), and co-trimoxazole (sxt) (an acsugstsxt resistance pattern). only one pulsed-field gel electrophoresis (pfge) type was detected, with 19 subtypes (simpson's index of diversity [sid]=0.89) ...201020943866
first report of salmonella enterica serotype paratyphi a azithromycin resistance leading to treatment failure.the prevalence of salmonella enterica serotype paratyphi a infection is increasing, and multidrug resistance is a well-recognized problem. resistance to fluoroquinolones is common and leads to more frequent use of newer agents like azithromycin. we report the first case of azithromycin resistance and treatment failure in a patient with s. paratyphi a infection.201020943875
chemical composition, antioxidant and antibacterial properties of the essential oils of etlingera elatior and cinnamomum pubescens kochummen.plant essential oils are widely used as fragrances and flavours. therefore, the essential oils from the leaves of cinnamomum pubescens kochummen (cp) and the whole plant of etlingera elatior (ee) were investigated for their antioxidant, antibacterial and phytochemical properties.201020945508
krüppel-like factor 4, a novel transcription factor regulates microglial activation and subsequent neuroinflammation.activation of microglia, the resident macrophages of the central nervous system (cns), is the hallmark of neuroinflammation in neurodegenerative diseases and other pathological conditions associated with cns infection. the activation of microglia is often associated with bystander neuronal death. nuclear factor-κb (nf-κb) is one of the important transcription factors known to be associated with microglial activation which upregulates the expression of inducible nitric oxide synthase (inos), cycl ...201020946687
purification of mbp-envz fusion proteins using an automated system.bacteria use two-component signal transduction systems to detect and respond to environmental changes. these systems have been studied systematically in escherichia coli as a model organism. most of the signal transduction systems present in e. coli are conserved in related pathogenic bacteria; however, differences in regulation by these systems have been reported from one bacterial species to another [oropeza, r., and calva, e. (2009). the cysteine 354 and 277 residues of salmonella enterica se ...201020946843
salmonella pathogenesis and processing of secreted effectors by caspase-3.the enteric pathogen salmonella enterica serovar typhimurium causes food poisoning resulting in gastroenteritis. the s. typhimurium effector salmonella invasion protein a (sipa) promotes gastroenteritis by functional motifs that trigger either mechanisms of inflammation or bacterial entry. during infection of intestinal epithelial cells, sipa was found to be responsible for the early activation of caspase-3, an enzyme that is required for sipa cleavage at a specific recognition motif that divide ...201020947770
outer membrane protein a of salmonella enterica serovar typhimurium activates dendritic cells and enhances th1 polarization.typhoid, which is caused by salmonella enterica serovar typhimurium, remains a major health concern worldwide. multidrug-resistant strains of salmonella have emerged which exhibit increased survivability and virulence, thus leading to increased morbidity. however, little is known about the protective immune response against this microorganism. the outer membrane protein (omp)a of bacteria plays an important role in pathogenesis.201020950448
the evolution and distribution of phage st160 within salmonella enterica serotype typhimurium.summarysalmonellosis is an internationally important disease of mammals and birds. unique epidemics in new zealand in the recent past include two salmonella serovars: salmonella enterica subsp. enterica serovar typhimurium definitive type (dt) 160 (s. typhimurium dt160) and s. brandenburg. although not a major threat internationally, in new zealand s. typhimurium dt160 has been the most common serovar isolated from humans, and continues to cause significant losses in wildlife. we have identified ...201020950514
salmonella enterica serovar agona european outbreak associated with a food company.summarywe investigated an international outbreak of salmonella agona with a distinct pfge pattern associated with an irish food company (company x) producing pre-cooked meat products sold in various food outlet chains in europe. the outbreak was first detected in ireland. we undertook national and international case-finding, food traceback and microbiological investigation of human, food and environmental samples. we undertook a matched case-control study on irish cases. in total, 163 cases in s ...201020950515
validation of dna and rna real-time assays for food analysis using the hila gene of salmonella enterica serovars.in europe, alternative methods for the detection of food-borne pathogens can be used instead of the standard iso/cen reference protocol, if validated according to the protocol outlined in iso 16140, 2003. in this study, the performance of two novel methods for the detection of salmonella sp. using real-time pcr technology in tandem with an adapted two-step enrichment protocol were assessed and validated against a reference culture method, iso 6579, 2004. the dna and rna real-time pcr assays ampl ...201020951170
rapid multiple-locus variable-number tandem-repeats analysis of shigella spp. using multicolour capillary electrophoresis.the multiple-locus variable-number tandem-repeats analysis (mlva) method for genotyping has proven to be a fast and reliable typing tool in several bacterial species. mlva is in our laboratory the routine typing method for salmonella enterica subsp. enterica serovar typhimurium, escherichia coli (two assays), listeria monocytogenes and yersinia enterocolitica. the gram-negative invasive enteropathogenic bacterium shigella is the most common cause of bacillary dysentery (shigellosis) worldwide, a ...201020951171
probiotic properties of lactobacillus strains isolated from the feces of breast-fed infants and taiwanese pickled cabbage.this study assessed potential probiotic lactobacillus strains isolated from the feces of breast-fed infants and from taiwanese pickled cabbage for their possible use in probiotic fermented foods by evaluating their (i) in vitro adhesive ability, resistance to biotic stress, resistance to pathogenic bacteria, and production of β-galactosidase; (ii) milk technological properties; and (iii) in vivo adhesive ability, intestinal survival and microbial changes during and after treatment. five lactobac ...201020951815
a mouse model for the human pathogen salmonella typhi.salmonella enterica serovar typhi (s. typhi) causes typhoid fever, a life-threatening human disease. the lack of animal models due to s. typhi's strict human host specificity has hindered its study and vaccine development. we find that immunodeficient rag2(-/-) γc(-/-) mice engrafted with human fetal liver hematopoietic stem and progenitor cells are able to support s. typhi replication and persistent infection. a s. typhi mutant in a gene required for virulence in humans was unable to replicate ...201020951970
detection of changes in the cellular composition of salmonella enterica serovar typhimurium in the presence of antimicrobial compound(s) of lactobacillus strains using fourier transform infrared spectroscopy.it was previously established that lactobacillus fermentum aca-dc 179, lactobacillus plantarum aca-dc 287 and lactobacillus plantarum aca-dc 2350 exhibit antimicrobial activity against salmonella enterica serovar typhimurium. in order to further investigate the killing effect of these microorganisms against salmonella cells, we employed fourier transform infrared spectroscopy (ft-ir). salmonella cells were incubated with different concentrated lactobacilli supernatants and their ft-ir spectra we ...201020952082
contribution of enhanced efflux to reduced susceptibility of salmonella enterica serovar choleraesuis to fluoroquinolone and other antimicrobials.we examined antimicrobial susceptibility and efflux systems in laboratory-derived mutants of salmonella enterica serovar choleraesuis selected by culture on fluoroquinolone-containing plates. the mutants exhibited decreased susceptibilities to quinolones and several other antimicrobials. mutations in the gyra gene were not always found in the mutants. accumulation assays revealed that intracellular enrofloxacin concentrations were significantly lower in the mutants compared with parent isolates. ...201020953129
molecular and phenotypic characteristics of cmy-2 β-lactamase-producing salmonella enterica serovar typhimurium isolated from cattle in japan.isolates of extended-spectrum cephalosporin (esc)-resistant salmonella enterica serovar typhimurium obtained from two different farms in fukushima prefecture, japan, in 2007 were characterized in order to determine the genetic basis of resistance. esc resistance in the two isolates was mediated by an ampc β-lactamase encoded by the bla(cmy-2) gene, which is located in a large self-transmissible plasmid in each isolate. the sizes of the bla(cmy-2)-carrying plasmids were different. the replicon ty ...201020953133
immunological, antioxidative, and morphological response in combined treatment of ofloxacin and lactobacillus fermentum me-3 probiotic in salmonella typhimurium murine model.we aimed to elucidate the immunological (cytokines), biochemical (antioxidative), and patho-morphological responses in the gut and liver evoked by the addition of lactobacillus fermentum me-3 to ofloxacin (ofx) treatment in an experimental infection model of salmonella enterica serovar typhimurium. after challenge with s. typhimurium and treatment according to different schemes, either with ofx and/or addition of l. fermentum me-3, the mice were killed. blood, liver, spleen, and small intestine ...201020955459
evaluation of the taxonomic utility of six-enzyme pulsed-field gel electrophoresis in reconstructing salmonella subspecies phylogeny.pulsed-field gel electrophoresis (pfge) remains an important tool in the molecular epidemiological evaluation of strains emerging from disease outbreak clusters. recent studies of escherichia coli o157:h7 and salmonella enteritidis have noted marked improvements in the discriminatory power of pfge when combining band profiles from up to six restriction enzyme datasets into a single concatenated analysis. this approach has provided more accurate assignments of genetic relationships among closely ...201020959148
phenotypic profile linked to inhibition of the major zn influx system in salmonella enterica: proteomics and ionomics investigations.zinc is required for a wide variety of cellular functions and plays a key role in bacterial metabolism and virulence. however, zn can also be toxic and, therefore, its influx is tightly regulated. the high affinity zinc uptake transporter znuabc is the main zn influx system in salmonella enterica under conditions of zn starvation. it has been shown that deletion of the gene encoding for its periplasmic subunit znua significantly affects s. typhimurium growth rate and virulence, highlighting the ...201020959928
different mutations in the oafa gene lead to loss of o5-antigen expression in salmonella enterica serovar typhimurium.to analyse genetic changes in the oafa gene explaining the loss of o5-antigen expression in salmonella typhimurium and salm. 4,[5],12:i:-.201020961365
development of multiplex real-time pcr with internal amplification control for simultaneous detection of salmonella and cronobacter in powdered infant formula.contamination of powdered infant formula (pif) by the bacteria cronobacter spp. and salmonella enterica was deemed a matter of great concern by the world health organization and the food and agriculture organization of the united nations in 2004. therefore, we developed a rapid and sensitive multiplex real-time pcr assay for the simultaneous detection of cronobacter and salmonella in pif. in addition, an internal amplification control (iac) was also included for exclusion of false negative resul ...201020961642
puo-sevr1 is an emergent virulence-resistance complex plasmid of salmonella enterica serovar enteritidis. 201020961912
fast detection of volatile organic compounds from bacterial cultures by secondary electrospray ionization-mass spectrometry.we propose a novel application of secondary electrospray ionization-mass spectrometry (sesi-ms) as a real-time clinical diagnostic tool for bacterial infection. it is known that volatile organic compounds (vocs), produced in different combinations and quantities by bacteria as metabolites, generate characteristic odors for certain bacteria. these vocs comprise a specific metabolic profile that can be used for species or serovar identification, but rapid and sensitive analytical methods are requi ...201020962140
salmonella newport omphaloarteritis in a stranded killer whale (orcinus orca) neonate.salmonella enterica serovar newport (salmonella newport) was isolated from multiple tissues in a neonate killer whale (orcinus orca) that stranded dead in 2005 along the central coast of california, usa. necrotizing omphaloarteritis and omphalophlebitis was observed on histologic examination suggesting umbilical infection was the route of entry. genetic analysis of skin samples indicated that the neonate had an offshore haplotype. salmonellosis has rarely been identified in free-ranging marine m ...201020966284
phylogenetic evaluation of the 'typhimurium' complex of salmonella strains using a seven-gene multi-locus sequence analysis.salmonella enterica comprises over 2500 serovars, many of which are significant foodborne pathogens in humans. the ability to subtype these microbes is difficult due to the highly clonal nature of many salmonella strains and a lack of congruence among traditional typing approaches. this work examines the phylogenetic utility of a multi-locus sequence typing (mlst) approach to discriminate between members of a closely related collection of salmonellae, the salmonella reference collection a (sara) ...201020970525
novel cooperation experimentally evolved between species.cooperation violates the view of "nature red in tooth and claw" that prevails in our understanding of evolution, yet examples of cooperation abound. most work has focused on maintenance of cooperation within a single species through mechanisms such as kin selection. the factors necessary for the evolutionary origin of aiding unrelated individuals such as members of another species have not been experimentally tested. here, i demonstrate that cooperation between species can be evolved in the labo ...201020100214
characterization of a novel sialic acid transporter of the sodium solute symporter (sss) family and in vivo comparison with known bacterial sialic acid transporters.the function of sialic acids in the biology of bacterial pathogens is reflected by the diverse range of solute transporters that can recognize these sugar acids. here, we use an escherichia colideltanant strain to characterize the function of known and proposed bacterial sialic acid transporters. we discover that the stm1128 gene from salmonella enterica serovar typhimurium, which encodes a member of the sodium solute symporter family, is able to restore growth on sialic acid to the deltanant st ...201020100283
characterization of small cole1-like plasmids conferring kanamycin resistance in salmonella enterica subsp. enterica serovars typhimurium and newport.multi-antibiotic resistant (mr) salmonella enterica serovars typhimurium and newport are an increasing concern in human and animal health. many strains are known to carry antibiotic resistance determinants on multiple plasmids, yet detailed information has been scarce. three plasmids conferring kanamycin (kan) resistance were isolated and nucleotide sequences were determined. two kan(r) plasmids from salmonella newport strains, psn11/00kan and psn02/01kan, were found to be identical and were 569 ...201020100512
both hemolytic anemia and malaria parasite-specific factors increase susceptibility to nontyphoidal salmonella enterica serovar typhimurium infection in mice.severe pediatric malaria is an important risk factor for developing disseminated infections with nontyphoidal salmonella serotypes (nts). while recent animal studies on this subject are lacking, early work suggests that an increased risk for developing systemic nts infection during malaria is caused by hemolytic anemia, which leads to reduced macrophage microbicidal activity. here we established a model for oral salmonella enterica serotype typhimurium challenge in mice infected with plasmodium ...201020100860
recombinant flagellins with partial deletions of the hypervariable domain lose antigenicity but not mucosal adjuvancy.flagellin contains conserved n/c domains for tlr5 binding to activate innate immunity and a middle hypervariable domain harboring the major antigenic epitopes. however, conflict results existed in the previous studies as to whether the hypervariable domain was involved in the cytokine production and adjuvancy of flagellin. here we constructed three flagellin variants (designated as flicdelta190-278, flicdelta220-320, and flicdelta180-400) with deletions in the hypervariable domain. our data demo ...201020102702
ndp52, a novel autophagy receptor for ubiquitin-decorated cytosolic bacteria.autophagy functions as a cell-autonomous effector mechanism of innate immunity by separating bacteria from cytosolic resources and delivering them for lysosomal destruction. how cytosolic bacteria are targeted for autophagy is incompletely understood. we recently discovered that salmonella enterica serotype typhimurium and streptococcus pyogenes are detected by ndp52 (nuclear dot protein 52 kda), after these bacteria enter the cytosol of human cells and become decorated with polyubiquitinated pr ...201020104023
empyema of preexisting subdural hemorrhage caused by a rare salmonella species after exposure to bearded dragons in a foster home.an infant had a subdural empyema caused by the rare salmonella species enterica subspecies houtenae (iv) serotype 44:z4,z23:- after only indirect exposure to exotic reptiles in her foster home. infants recovering from preexisting subdural hematoma are at risk for development of empyema.201020105642
prime-boost immunization using a dna vaccine delivered by attenuated salmonella enterica serovar typhimurium and a killed vaccine completely protects chickens from h5n1 highly pathogenic avian influenza virus.h5n1 highly pathogenic avian influenza virus (hpaiv) has posed a great threat not only for the poultry industry but also for human health. however, an effective vaccine to provide a full spectrum of protection is lacking in the poultry field. in the current study, a novel prime-boost vaccination strategy against h5n1 hpaiv was developed: chickens were first orally immunized with a hemagglutinin (ha) dna vaccine delivered by attenuated salmonella enterica serovar typhimurium, and boosting with a ...201020107004
development of a bead immunoassay to measure vi polysaccharide-specific serum igg after vaccination with the salmonella enterica serovar typhi vi polysaccharide.vi polysaccharide from salmonella enterica serotype typhi is used as one of the available vaccines to prevent typhoid fever. measurement of vi-specific serum antibodies after vaccination with vi polysaccharide by enzyme-linked immunosorbent assay (elisa) may be complicated due to poor binding of the vi polysaccharide to elisa plates resulting in poor reproducibility of measured antibody responses. we chemically conjugated vi polysaccharide to fluorescent beads and performed studies to determine ...201020107010
development and evaluation of a multiplex real-time polymerase chain reaction procedure to clinically type prevalent salmonella enterica serovars.a multiplex real-time polymerase chain reaction procedure was developed to identify the most prevalent clinical isolates of salmonella enterica subsp. enterica. genes from the rfb, flic, fljb, and viab groups that encode the o, h, and vi antigens were used to design 15 primer pairs and taqman probes specific for the genes rfbj, wzx, flic, fljb, wcdb, the sdf-l sequence, and inva, which was used as an internal amplification control. the primers and probes were variously combined into six sets. th ...201020110454
interaction of saccharomyces boulardii with salmonella enterica serovar typhimurium protects mice and modifies t84 cell response to the infection.salmonella pathogenesis engages host cells in two-way biochemical interactions: phagocytosis of bacteria by recruitment of cellular small gtp-binding proteins induced by the bacteria, and by triggering a pro-inflammatory response through activation of mapks and nuclear translocation of nf-kappab. worldwide interest in the use of functional foods containing probiotic bacteria for health promotion and disease prevention has increased significantly. saccharomyces boulardii is a non-pathogenic yeast ...201020111723
inhibition of the early stage of salmonella enterica serovar enteritidis biofilm development on stainless steel by cell-free supernatant of a hafnia alvei culture.compounds present in hafnia alvei cell-free culture supernatant cumulatively negatively influence the early stage of biofilm development by salmonella enterica serovar enteritidis on stainless steel while they also reduce the overall metabolic activity of s. enteritidis planktonic cells. although acylhomoserine lactones (ahls) were detected among these compounds, the use of several synthetic ahls was not able to affect the initial stage of biofilm formation by this pathogen.201020097823
the zur-regulated zint protein is an auxiliary component of the high-affinity znuabc zinc transporter that facilitates metal recruitment during severe zinc shortage.the pathways ensuring the efficient uptake of zinc are crucial for the ability of bacteria to multiply in the infected host. to better understand bacterial responses to zinc deficiency, we have investigated the role of the periplasmic protein zint in salmonella enterica serovar typhimurium. we have found that zint expression is regulated by zur and parallels that of znua, the periplasmic component of the zinc transporter znuabc. despite the fact that zint contributes to salmonella growth in medi ...201020097857
qsec mediates salmonella enterica serovar typhimurium virulence in vitro and in vivo.the autoinducer-3 (ai-3)/epinephrine (epi)/norepinephrine (ne) interkingdom signaling system mediates chemical communication between bacteria and their mammalian hosts. the three signals are sensed by the qsec histidine kinase (hk) sensor. salmonella enterica serovar typhimurium is a pathogen that uses hks to sense its environment and regulate virulence. salmonella serovar typhimurium invades epithelial cells and survives within macrophages. invasion of epithelial cells is mediated by the type i ...201020028809
combined ramr mutation and presence of a tn1721-associated tet(a) variant in a clinical isolate of salmonella enterica serovar hadar resistant to tigecycline.a salmonella enterica serovar hadar strain resistant to tigecycline (mic, 16 microg/ml) was isolated. molecular characterization revealed the presence of a plasmid-borne tet(a) variant associated with tn1721 mediating a rise of the mic for tigecycline when transferred to escherichia coli. additionally, a truncating mutation in ramr was detected. transformation with wild-type ramr but not with the mutated ramr lowered the mic for tigecycline. characterization of this salmonella isolate implicates ...201020028818
ceftiofur resistance in salmonella enterica serovar heidelberg from chicken meat and humans, canada.the canadian integrated program for antimicrobial resistance surveillance describes a strong correlation (r = 0.9, p<0.0001) between ceftiofur-resistant salmonella enterica serovar heidelberg isolated from retail chicken and incidence of ceftiofur-resistant salmonella serovar heidelberg infections in humans across canada. in quebec, changes of ceftiofur resistance in chicken salmonella heidelberg and escherichia coli isolates appear related to changing levels of ceftiofur use in hatcheries durin ...201020031042
the designer proline-rich antibacterial peptide a3-apo is effective against systemic escherichia coli infections in different mouse models.antimicrobial peptides are considered to be viable alternatives to conventional antibiotics. however, they rarely show systemic efficacy in animal models when added at non-toxic doses. the dimer a3-apo was designed to attack both the bacterial membrane and the enterobacteriaceae-specific domain of the heat shock protein dnak in order to reduce toxicity whilst maintaining activity. the peptide exhibited a minimal inhibitory concentration (mic) range of 2-128 mg/l against 28 clinical escherichia c ...201020031377
molecular characterization of extended-spectrum cephalosporinase-producing salmonella enterica serovar choleraesuis isolates from patients in thailand and denmark.the objective of this study was to characterize extended-spectrum cephalosporinase (esc)-producing isolates of salmonella enterica serovar choleraesuis recovered from patients in thailand and denmark. twenty-four blood culture isolates from 22 patients were included in the study, of which 23 isolates were recovered from 21 thai patients during 2003, 2007, or 2008 and one isolate was recovered from a danish traveler to thailand. esc production was confirmed in 13 out of the 24 isolates by mic tes ...201020032253
the role of the flik molecular ruler in hook-length control in salmonella enterica.a molecular ruler, flik, controls the length of the flagellar hook. flik measures hook length and catalyses the secretion-substrate specificity switch from rod-hook substrate specificity to late substrate secretion, which includes the filament subunits. here, we show normal hook-length control and filament assembly in the complete absence of the c-ring thus refuting the previous 'cup' model for hook-length control. mutants of c-ring components, which are reported to produce short hooks, show a r ...201020132451
carvacrol and cinnamaldehyde inactivate antibiotic-resistant salmonella enterica in buffer and on celery and oysters.the emergence of antibiotic-resistant salmonella is of concern to food processors. the objective of this research was to identify antimicrobial activities of cinnamaldehyde and carvacrol against antibiotic-resistant salmonella enterica in phosphate-buffered saline (pbs) and on celery and oysters. twenty-three isolates were screened for resistance to seven antibiotics. two resistant and two susceptible strains were chosen for the study. s. enterica cultures (10(5) cfu/ml) were added to different ...201020132667
use of electron beam radiation for the reduction of salmonella enterica serovars typhimurium and tennessee in peanut butter.peanut butter and peanut paste products were implicated as the vehicle of contamination in an outbreak of salmonella typhimurium, which began in september 2008, and in the november 2006 outbreak of salmonella tennessee. therefore, this study evaluated the effectiveness of electron beam (e-beam) radiation for the reduction of salmonella serovars tennessee (atcc 10722) and typhimurium (atcc 14028) in creamy peanut butter. each strain was studied independently. peanut butter samples were inoculated ...201020132682
dynamics of intracellular bacterial replication at the single cell level.several important pathogens cause disease by surviving and replicating within host cells. bacterial proliferation is the product of both replication and killing undergone by the population. however, these processes are difficult to distinguish, and are usually assessed together by determination of net bacterial load. in addition, measurement of net load does not reveal heterogeneity within pathogen populations. this is particularly important in persistent infections in which slow or nongrowing b ...201020133586
an oligonucleotide microarray to characterize multidrug resistant plasmids.many of the enterobacteriaceae carry multiple drug resistance (mdr) genes on large plasmids of replicon type inc a/c and inc h1. it is important to understand the transmission of these mdr plasmids because the genes they carry can affect the outcome of antimicrobial therapy. the aim of this study was to design a microarray with oligonucleotide probes for every gene in the six inc a/c and one inc h1 plasmids of interest while representing all redundant sequences only once. the microarray is print ...201020138094
genetic modification of the salmonella membrane physical state alters the pattern of heat shock response.it is now recognized that membranes are not simple physical barriers but represent a complex and dynamic environment that affects membrane protein structures and their functions. recent data emphasize the role of membranes in sensing temperature changes, and it has been shown that the physical state of the plasma membrane influences the expression of a variety of genes such as heat shock genes. it has been widely shown that minor alterations in lipid membranes are critically involved in the conv ...201020139186
relevance of dna alkylation damage repair systems in salmonella enterica virulence.systematic inactivation of pathways involved in dna alkylation damage repair demonstrated that inactivation of the ada, ogt, tag, uvra, and mfd genes is required to detect a salmonella enterica virulence decrease. furthermore, the fitness of s. enterica, defective in these genes, is lowered only when the bacterium is orally, but not intraperitoneally, inoculated.201020139190
changes in membrane fluid state and heat shock response cause attenuation of virulence.so far attenuation of pathogens has been mainly obtained by chemical or heat treatment of microbial pathogens. recently, live attenuated strains have been produced by genetic modification. we have previously demonstrated that in several prokaryotes as well as in yeasts and mammalian cells the heat shock response is controlled by the membrane physical state (mps). we have also shown that in salmonella enterica serovar typhimurium lt2 (salmonella typhimurium) overexpression of a delta(12)-desatura ...201020139193
synthesis of ag/cnt hybrid nanoparticles and fabrication of their nylon-6 polymer nanocomposite fibers for antimicrobial applications.ag-coated cnts hybrid nanoparticles (ag/cnts) were prepared by ultrasonic irradiation of dimethylformamide (dmf) and silver (i) acetate precursors in the presence of cnts. the morphology of ag/cnts was characterized using x-ray diffraction and transmission electron microscopy (tem) techniques. the nylon-6 powder and 1 wt% ag/cnts mixture was dispersed uniformly using a noncontact spinning technique. the dried mixture was melted in a single screw extrusion machine and then extruded through an ori ...201020139493
structural and biochemical characterization of srca, a multi-cargo type iii secretion chaperone in salmonella required for pathogenic association with a host.many gram-negative bacteria colonize and exploit host niches using a protein apparatus called a type iii secretion system (t3ss) that translocates bacterial effector proteins into host cells where their functions are essential for pathogenesis. a suite of t3ss-associated chaperone proteins bind cargo in the bacterial cytosol, establishing protein interaction networks needed for effector translocation into host cells. in salmonella enterica serovar typhimurium, a t3ss encoded in a large genomic i ...201020140193
chicken meat is an infection source of salmonella serovar infantis for humans in japan.the study sets out to either confirm or refute a recent study's findings that chicken meat is an unlikely source of salmonella enterica subspecies enterica serovar infantis (salmonella infantis) in humans in the kyushu-okinawa region, japan.201020141347
antibacterial activity of carvacrol and 2-nitro-1-propanol against single and mixed populations of foodborne pathogenic bacteria in corn flour dough.cereal doughs are an important part of human diet, but at the same time can act as vehicles for the transmission of human pathogenic bacteria. in the present study, four pathogenic or toxinogenic bacteria (escherichia coli o157:h7, salmonella enterica serovar enteritidis, bacillus cereus and staphylococcus aureus) were inoculated in a dough made from corn flour in combination with the single antimicrobial compounds carvacrol and 2-nitro-1-propanol (2npoh). survival of single and mixed population ...201020141946
so similar, yet so different: uncovering distinctive features in the genomes of salmonella enterica serovars typhimurium and typhi.salmonella enterica represents a major human and animal pathogen. many s. enterica genomes have been completed and many more genome sequencing projects are underway, constituting an excellent resource for comparative genome analysis studies leading to a better understanding of bacterial evolution and pathogenesis. salmonella enterica serovar typhimurium and typhi are the best-characterized serovars, with the first being involved in localized gastroenteritis in many hosts and the latter causing a ...201020146749
salmonella enterica serovar typhimurium vaccine strains expressing a nontoxic shiga-like toxin 2 derivative induce partial protective immunity to the toxin expressed by enterohemorrhagic escherichia coli.shiga-like toxin 2 (stx2)-producing enterohemorrhagic escherichia coli (referred to as ehec or stec) strains are the primary etiologic agents of hemolytic-uremic syndrome (hus), which leads to renal failure and high mortality rates. expression of stx2 is the most relevant virulence-associated factor of ehec strains, and toxin neutralization by antigen-specific serum antibodies represents the main target for both preventive and therapeutic anti-hus approaches. in the present report, we describe t ...201020147499
elucidation of the outer membrane proteome of salmonella enterica serovar typhimurium utilising a lipid-based protein immobilization technique.salmonella enterica serovar typhimurium (s. typhimurium) is a major cause of human gastroenteritis worldwide. the outer membrane proteins expressed by s. typhimurium mediate the process of adhesion and internalisation within the intestinal epithelium of the host thus influencing the progression of disease. since the outer membrane proteins are surface-exposed, they provide attractive targets for the development of improved antimicrobial agents and vaccines. various techniques have been developed ...201020149234
characterization of antimicrobial resistance, molecular and phage types of salmonella enterica serovar typhi isolations.isolation rates in canada of salmonella enterica serovar typhi increased from 0.29 to 0.55 isolations/100,000 population during 2000-2006. although no ciprofloxacin resistance was detected, nalidixic acid resistance increased from 41% to 80%. multidrug-resistant s. typhi represented 18% of the strains tested. pulsed-field gel electrophoresis (pfge) analysis of 222 isolates resulted in 91 distinct patterns clustering into four major genetic similarity groups. the five most frequently occurring pf ...201020149265
further evidence of plasmid-encoded bla-(ctx-m-15) and bla-(tem-1) genes in lebanese isolates of salmonella enterica serovar typhimurium that produce extended-spectrum beta-lactamase. 201020149296
ribosomes lacking protein s20 are defective in mrna binding and subunit association.the functional significance of ribosomal proteins is still relatively unclear. here, we examined the role of small subunit protein s20 in translation using both in vivo and in vitro techniques. by means of lambda red recombineering, the rpst gene, encoding s20, was removed from the chromosome of salmonella enterica var. typhimurium lt2 to produce a deltas20 strain that grew markedly slower than the wild type while maintaining a wild-type rate of peptide elongation. removal of s20 conferred a sig ...201020149799
characterisation of pathogenic bacteria in a uasb-polishing pond system using molecular techniques.molecular techniques have been commonly used to detect and quantify pathogenic bacteria in food, clinical and environmental samples, but in wastewater treatment plants few studies have been carried out. this work applied pcr with a specific set of primers to investigate pathogenic bacteria in a wastewater plant comprised of a uasb reactor followed by polishing ponds. in addition, in-situ hybridisation technique (fish) was used to estimate the abundance of escherichia coli in the system. accordin ...201020150719
molecular basis for endotoxin neutralization by amphipathic peptides derived from the alpha-helical cationic core-region of nk-lysin.an analysis of the interaction of the nk-lysin derived peptide nk-2 and of analogs thereof with bacterial lipopolysaccharide (lps, endotoxin) was performed to determine the most important biophysical parameters for an effective lps neutralization. we used microcalorimetry, ftir spectroscopy, zeta potential measurements, and small-angle x-ray scattering to analyze the peptide:lps binding enthalpy, the accessible lps surface charge, the fluidity of the lps hydrocarbon chains, their phase transitio ...201020153101
protecting against antimicrobial effectors in the phagosome allows sodcii to contribute to virulence in salmonella enterica serovar typhimurium.salmonella enterica serovar typhimurium replicates in macrophages, where it is subjected to antimicrobial substances, including superoxide, antimicrobial peptides, and proteases. the bacterium produces two periplasmic superoxide dismutases, sodci and sodcii. although both are expressed during infection, only sodci contributes to virulence in the mouse by combating phagocytic superoxide. the differential contribution to virulence is at least partially due to inherent differences in the sodci and ...201020154132
the second extracellular loop of pore-forming subunits of atp-binding cassette transporters for basic amino acids plays a crucial role in interaction with the cognate solute binding protein(s).in the thermophile geobacillus stearothermophilus, the uptake of basic amino acids is mediated by an abc transporter composed of the substrate binding protein (receptor) artj and a homodimer each of the pore-forming subunit, artm, and the nucleotide-binding subunit, artp. we recently identified two putative binding sites in artj that might interact with the art(mp)(2) complex, thereby initiating the transport cycle (a. vahedi-faridi et al., j. mol. biol. 375:448-459, 2008). here we investigated ...201020154136
the occurrence and sources of campylobacter spp., salmonella enterica and escherichia coli o157:h7 in the salmon river, british columbia, canada.in this study, we wished to assess the prevalence and determine the sources of three zoonotic bacterial pathogens (salmonella, campylobacter, and escherichia coli o157:h7) in the salmon river watershed in southwestern british columbia. surface water, sewage, and animal faecal samples were collected from the watershed. selective bacterial culture and pcr techniques were used to isolate these three pathogens and indicator bacteria from these samples and characterize them. campylobacter was the mos ...201020154400
eric pcr and rapd based fingerprinting of salmonella typhi strains isolated over a period of two decades.salmonella enterica serotype typhi strains (n=113) were isolated from typhoid patients over a period of 2 decades, i.e. 1987-2006. rapd and eric pcr methods were used for random whole genome typing of these strains. eric pcr was found to be very efficient with the discriminatory index (di) of 0.9821 with 100% reproducibility. rapd was satisfactory in discriminating the strains (di=0.8978) but with poor reproducibility (40%). however, composite genotypic analysis was still better with di of 0.998 ...201020156601
virulence mechanisms displayed by salmonella to impair dendritic cell function.dendritic cells (dcs) link innate and adaptive immunity by directly recognizing pathogen-associated molecular patterns (pamps) on bacteria. dcs can capture and degrade bacteria and present their antigens on mhc molecules to t cells. pamp recognition promotes dc maturation, a phenotypic change that empowers them to prime naïve t cells. as a result, an adaptive immune response that specifically targets bacteria-derived antigens is initiated. consequently, any impairment of dc function might contri ...201020158475
the complexities of porin genetic regulation.our understanding of porin regulation has revealed not only increasing complexity in the regulatory mechanisms, but also that the porin repertoire is more extensive than previously conceived. initially, the ompr response regulator was described as the master regulator of porin genes, but many more regulators are involved such as cpxr, phob, lrp, rob, mara, soxs, cadc, crp, fnr, toxr, h-ns, stpa, ihf, hu and leuo. in addition to micf, the first small rna (srna) that was proposed to regulate porin ...201020068355
tracking the dynamic interplay between bacterial and host factors during pathogen-induced vacuole rupture in real time.escape into the host cell cytosol following invasion of mammalian cells is a common strategy used by invasive pathogens. this requires membrane rupture of the vesicular or vacuolar compartment formed around the bacteria after uptake into the host cell. the mechanism of pathogen-induced disassembly of the vacuolar membrane is poorly understood. we established a novel, robust and sensitive fluorescence microscopy method that tracks the precise time point of vacuole rupture upon uptake of gram-nega ...201020070313
molecular typing of salmonella enterica serovar sofia in australia by pulsed-field gel electrophoresis and repetitive element pcr typing.in this study, we used two molecular fingerprinting methods to investigate the genetic and clonal relationship shared by australian salmonella sofia isolates.201020070444
vaccination of mice with salmonella expressing vapa: mucosal and systemic th1 responses provide protection against rhodococcus equi infection.conventional vaccines to prevent the pneumonia caused by rhodococcus equi have not been successful. we have recently demonstrated that immunization with salmonella enterica typhimurium expressing the vapa antigen protects mice against r. equi infection. we now report that oral vaccination of mice with this recombinant strain results in high and persistent fecal levels of antigen-specific iga, and specific proliferation of the spleen cells of immunized mice in response to the in vitro stimulation ...201020072623
glucose and glucose 6-phosphate as carbon sources in extra- and intracellular growth of enteroinvasive escherichia coli and salmonella enterica.to study the role of carbohydrates, in particular glucose, glucose 6-phosphate and mannose, as carbon substrates for extra- and intracellular replication of facultative intracellular enteric bacteria, mutants of two enteroinvasive escherichia coli (eiec) strains and a salmonella enterica serovar typhimurium isolate were constructed that were defective in the uptake of glucose and mannose (deltaptsg, manxyz), glucose 6-phosphate (deltauhpt) or all three carbohydrates (deltaptsg, manxyz, uhpt). th ...201020075042
prevalence and characterization of salmonella gallinarum in the chicken in korea during 2000 to 2008.salmonella enterica serovar gallinarum (salmonella gallinarum) is the causative agent of fowl typhoid (ft), a severe systemic disease of chickens that results in high mortality. since 1992, ft has become one of the most serious bacterial diseases in poultry in korea. the purpose of this study was to investigate the prevalence of ft during 2000 to 2008 and characterize the phenotype and genetic diversity of salmonella gallinarum isolates before and after adopting national-wide vaccination with a ...201020075274
effect of lactic acid bacteria probiotic culture treatment timing on salmonella enteritidis in neonatal broilers.in the present study, a series of experiments were conducted to evaluate the ability of a combination of 3 atcc lactobacilli (lab3) or a commercially available probiotic culture (prob) to reduce salmonella enterica serovar enteritidis (salmonella enteritidis) in broiler chicks. additionally, we varied the timing of prob administration in relationship to salmonella challenge and determined the influence on recovery of enteric salmonella. in experiments 1 to 3, chicks were randomly assigned to tre ...201020075275
exploiting the role of tolc in pathogenicity: identification of a bacteriophage for eradication of salmonella serovars from poultry.using a screening procedure, three bacteriophages, st27, st29, and st35, were identified with selective activity for salmonella enterica serovar typhimurium (sl1344) but not sl1344 tolc::aph. overproduction of tolc led to a lower efficiency of plating (eop), further suggesting that tolc was the target receptor. activity against other serovars of salmonella was observed but not against other species of enterobacteriaceae. this study provides proof of principle that bacteriophages can be active ag ...201020080996
rama, a member of the arac/xyls family, influences both virulence and efflux in salmonella enterica serovar typhimurium.the transcriptomes of salmonella enterica serovar typhimurium sl1344 lacking a functional rama or ramr or with plasmid-mediated high-level overexpression of rama were compared to those of the wild-type parental strain. inactivation of rama led to increased expression of 14 spi-1 genes and decreased expression of three spi-2 genes, and it altered expression of ribosomal biosynthetic genes and several amino acid biosynthetic pathways. furthermore, disruption of rama led to decreased survival withi ...201020081028
interaction of bacillus species and salmonella enterica serovar typhimurium in immune or inflammatory signaling from swine intestinal epithelial cells.previous research evaluated a laboratory strain of bacillus licheniformis (bl) in a model swine epithelium and found it exerted antiinflammatory effects on salmonella enterica serovar typhimurium (sal)-induced secretion of il-8. the current investigation evaluated the antiinflammatory actions of bacillus bacteria available commercially as feed additives for the swine industry. three isolates were obtained from the product, 2 bacillus subtilis (bs1 and bs3) and 1 bl (bl2). swine jejunal epithelia ...201020081082
oral inoculation with salmonella enterica serovar typhimurium or choleraesuis promotes divergent responses in the somatotropic growth axis of swine.enteric disease and immune challenge are processes that have detrimental effects on the growth performance of young swine. the current study tested the hypothesis that salmonella-induced enteric disease would perturb the endocrine growth axis in a serovar-dependent fashion. specifically, we evaluated the effects of salmonella enterica serovar typhimurium (typhimurium) and serovar choleraesuis (choleraesuis) on critical regulatory components of growth in young swine. weaned pigs were housed 2 per ...201020081084
individual and co-operative roles of lactic acid and hydrogen peroxide in the killing activity of enteric strain lactobacillus johnsonii ncc933 and vaginal strain lactobacillus gasseri ks120.1 against enteric, uropathogenic and vaginosis-associated pathogens.the mechanism underlying the killing activity of lactobacillus strains against bacterial pathogens appears to be multifactorial. here, we investigate the respective contributions of hydrogen peroxide and lactic acid in killing bacterial pathogens associated with the human vagina, urinary tract or intestine by two hydrogen peroxide-producing strains. in co-culture, the human intestinal strain lactobacillus johnsonii ncc933 and human vaginal strain lactobacillus gasseri ks120.1 strains killed ente ...201020082639
evaluation of isotope-coded protein labeling (icpl) in the quantitative analysis of complex proteomes.an evaluation of the icpl (isotope-coded protein labeling) non-isobaric labeling technique was performed using two different biological models. two samples containing phage t4 capsids were mixed in a 1:1 ratio after being labeled with the light or heavy versions of the icpl reagent. the analysis of this proteome demonstrated the feasibility of this approach for differential quantitative proteomics and was employed to optimize the experimental parameters of the icpl workflow. icpl-mediated analys ...201020082807
regulation of bacterial conjugation in microaerobiosis by host-encoded functions arcab and sdhabcd.the virulence plasmid of salmonella enterica (pslt) is an f-like conjugative plasmid. high rates of pslt transfer occur in the mammalian gut, a microaerobic environment. in this study, we describe genetic screens for host-encoded activators and repressors of the transfer operon (tra) of pslt. we show that the transcription factor arca is an activator of conjugation, especially under microaerobiosis. in turn, succinate dehydrogenase (sdhabcd) is a repressor of mating in aerobiosis. arca binds ups ...201020083612
duplication frequency in a population of salmonella enterica rapidly approaches steady state with or without recombination.tandem duplications are among the most common mutation events. the high loss rate of duplication suggested that the frequency of duplications in a bacterial population (1/1000) might reflect a steady state dictated by relative rates of formation (k(f)) and loss (k(l)). this possibility was tested for three genetic loci. without homologous recombination (reca), duplication loss rate dropped essentially to zero, but formation rate decreased only slightly and a steady state was still reached rapidl ...201020083614
expression of homing receptors on iga1 and iga2 plasmablasts in blood reflects differential distribution of iga1 and iga2 in various body fluids.although secretory iga is the most abundantly produced ig isotype, the mechanisms underlying the differential distribution of iga subclasses in various body fluids remain unclear. to explore these mechanisms, we examined the distribution of iga subclasses, the influence of the nature and sites of encounters with antigens, and the correlation between iga subclass distribution and homing potentials of circulating iga plasmablasts. iga1 predominated in serum, tears, nasal wash fluid, and saliva; th ...201020089794
characterization of resistance genes in multidrug-resistant salmonella enterica serotype typhimurium isolated from diseased cattle in france (2002 to 2007).we report here the results of the survey of antimicrobial resistance in 148 serotype typhimurium strains isolated from cattle in france from 2002 to 2007 and displaying more than two antimicrobial resistances. salmonella enterica serotype typhimurium of definitive phage type 104 strains that are commonly resistant to ampicillin-amoxicillin, chloramphenicol-florfenicol, streptomycin-spectinomycin, sulfonamides, and tetracycline (acssut phenotype) harbored resistance genes clustered on a complex c ...201020092404
virulotyping and antimicrobial resistance typing of salmonella enterica serovars relevant to human health in europe.the combination of virulence gene and antimicrobial resistance gene typing using dna arrays is a recently developed genomics-based approach to bacterial molecular epidemiology. we have now applied this technology to 523 salmonella enterica subsp. enterica strains collected from various host sources and public health and veterinary institutes across nine european countries. the strain set included the five predominant salmonella serovars isolated in europe (enteritidis, typhimurium, infantis, vir ...201020039795
detection and characterization of extended-spectrum beta-lactamase (tem-52)-producing salmonella serotype infantis from broilers in japan.during 2004 and 2006, multidrug-resistant salmonella enterica subspecies enterica serovar infantis (salmonella infantis) isolates (n = 120) were recovered from broiler cecal samples collected from a meat-processing plant, and the isolates were examined. the study was conducted to detect and characterize extended-spectrum beta-lactamase (esbl)-producing salmonella infantis isolates recovered from broiler chickens and determine the mechanisms of transfer of the resistance traits. extended-spectrum ...201020039796
espm2 is a rhoa guanine nucleotide exchange factor.we investigated how the type iii secretion system wxxxe effectors espm2 of enterohaemorrhagic escherichia coli, which triggers stress fibre formation, and sifa of salmonella enterica serovar typhimurium, which is involved in intracellular survival, modulate rho gtpases. we identified a direct interaction between espm2 or sifa and nucleotide-free rhoa. nuclear magnetic resonance spectroscopy revealed that espm2 has a similar fold to sifa and the guanine nucleotide exchange factor (gef) effector s ...201020039879
successful treatment of refractory septic arthritis caused by salmonella and staphylococcus aureus with preservation of graft function in a long-term renal transplant recipient by total withdrawal of immunosuppressants.an 18-year-old female had received a 2 hla incompatible renal transplant 10 years before. she initially presented with septic arthritis and osteomyelitis caused by salmonella enterica co-infected with staphylococcus aureus of her left knee with development of secondary septic arthritis of the right knee and left shoulder. this was complicated by a recurrent subcutaneous abscess and intermittent high fever. the infection was successfully treated with a combination of a prolonged course of antibio ...201020040356
prevalence and risk factors for salmonella enterica subsp. enterica contamination in french breeding and fattening turkey flocks at the end of the rearing period.an epidemiological study was conducted to estimate the prevalence of salmonella spp. contamination in french commercial breeding and fattening turkey flocks at the end of the rearing period, as part of a european union-wide baseline study. two hundred and five breeding turkey flocks and three hundred and two fattening turkey flocks were included in the study, between october 2006 and september 2007. the salmonella status of flocks was assessed by collecting five environmental faeces samples, ana ...201020044159
structure and mechanisms of a protein-based organelle in escherichia coli.many bacterial cells contain proteinaceous microcompartments that act as simple organelles by sequestering specific metabolic processes involving volatile or toxic metabolites. here we report the three-dimensional (3d) crystal structures, with resolutions between 1.65 and 2.5 angstroms, of the four homologous proteins (euts, eutl, eutk, and eutm) that are thought to be the major shell constituents of a functionally complex ethanolamine utilization (eut) microcompartment. the eut microcompartment ...201020044574
deletion of penicillin-binding protein 5 (pbp5) sensitises escherichia coli cells to beta-lactam agents.escherichia coli penicillin-binding protein 5 (pbp5), a dd-carboxypeptidase encoded by the daca gene, plays a key role in the maintenance of cell shape. although pbp5 shares one of the highest copy numbers among the pbps, it is not essential for cell survival. to determine the effect of this redundant pbp on beta-lactam antibiotic susceptibility, pbp5 was deleted from o-antigen-negative e. coli k-12 (cs109) and o8-antigen-positive e. coli 2443, thus creating strains am15-1 and ag1o5-1, respectiv ...201020047819
changes in the proteome of salmonella enterica serovar thompson as stress adaptation to sublethal concentrations of thymol.thymol is a natural biocide and component of some essential oils from herbs. its inhibitory effect on the growth of different microorganisms is well documented. the precise targets of the antibacterial action of thymol is not yet been fully established, the action seems to take place in different ways. the strain salmonella enterica serovar thompson mcv1 was grown in the presence of a sublethal concentration (0.01%) of thymol. the proteins extracted from treated and untreated cells were subjecte ...201020049861
effect of alpha-cyclodextrin-cinnamic acid inclusion complexes on populations of escherichia coli o157:h7 and salmonella enterica in fruit juices.cinnamic acid (ca), a naturally occurring organic acid found in fruits and spices, has antimicrobial activity against spoilage and pathogenic bacteria, but low aqueous solubility limits its use. the purpose of this study was to determine the effectiveness of solubility-enhancing alpha-cyclodextrin-ca inclusion complexes against escherichia coli o157:h7 and salmonella enterica serovars suspended in apple cider or orange juice at two different incubation temperatures (4 and 26 degrees celsius). tw ...201020051210
immunogenicity of a live recombinant salmonella enterica serovar typhimurium vaccine expressing pspa in neonates and infant mice born from naive and immunized mothers.we are developing a salmonella vectored vaccine to prevent infant pneumonia and other diseases caused by streptococcus pneumoniae. one prerequisite for achieving this goal is to construct and evaluate new recombinant attenuated salmonella vaccine (rasv) strains suitable for use in neonates and infants. salmonella enterica serovar typhimurium strain chi9558(pya4088) specifies delivery of the pneumococcal protective antigen pspa and can protect adult mice from challenge with s. pneumoniae. this st ...201020053873
construction of recombinant attenuated salmonella enterica serovar typhimurium vaccine vector strains for safety in newborn and infant mice.recombinant bacterial vaccines must be safe, efficacious, and well tolerated, especially when administered to newborns and infants to prevent diseases of early childhood. many means of attenuation have been shown to render vaccine strains susceptible to host defenses or unable to colonize lymphoid tissue effectively, thus decreasing their immunogenicity. we have constructed recombinant attenuated salmonella vaccine strains that display high levels of attenuation while retaining the ability to in ...201020053874
effects of exposure to poultry chemical decontaminants on the membrane fluidity of listeria monocytogenes and salmonella enterica strains.there is a lack of work comparing the influence of various poultry chemical decontaminants on the membrane fluidity of pathogenic bacteria. in order to assess the possible role of physical membrane changes on bacterial adaptation to decontaminants, fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (dph) was measured in listeria monocytogenes and salmonella enterica strains before and after growth in the presence of increasing sub-lethal concentrations of decontaminants (trisodium phosphat ...201020056288
contrasting persistence strategies in salmonella and mycobacterium.long-term survival of persistent bacterial pathogens in mammalian hosts critically depends on their ability to avoid elimination by innate and adaptive immune responses. the persistent human pathogens that cause typhoid fever and tuberculosis exemplify alternative strategies for survival in the host: immune evasion and immune adaptation, respectively. salmonella enterica serotype typhi evades host innate immune responses and inflammation by expressing factors that interfere with its detection as ...201020056478
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