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novel genomic tools for specific and real-time detection of biothreat and frequently encountered foodborne pathogens.the bacterial genera escherichia, salmonella, shigella, vibrio, yersinia, and francisella include important food safety and biothreat agents. by extensive mining of the whole genome and protein databases of diverse, closely and distantly related bacterial species and strains, we have identified novel genome regions, which we utilized to develop a rapid detection platform for these pathogens. the specific genomic targets we have identified to design the primers in francisella tularensis subsp. tu ...201222488053
bacterial pathogens commandeer rab gtpases to establish intracellular niches.intracellular bacterial pathogens deploy virulence factors termed effectors to inhibit degradation by host cells and to establish intracellular niches where growth and differentiation take place. here, we describe mechanisms by which human bacterial pathogens (including chlamydiae; coxiella burnetii; helicobacter pylori; legionella pneumophila; listeria monocytogenes; mycobacteria; pseudomonas aeruginosa, salmonella enterica) modulate endocytic and exocytic rab gtpases in order to thrive in host ...201222901006
rapid discrimination of salmonella enterica serovar typhi from other serovars by maldi-tof mass spectrometry.systemic infections caused by salmonella enterica are an ongoing public health problem especially in sub-saharan africa. essentially typhoid fever is associated with high mortality particularly because of the increasing prevalence of multidrug-resistant strains. thus, a rapid blood-culture based bacterial species diagnosis including an immediate sub-differentiation of the various serovars is mandatory. at present, maldi-tof based intact cell mass spectrometry (icms) advances to a widely used rou ...201222768195
multidrug-resistant salmonella enterica serovar panama carrying class 1 integrons is invasive in taiwanese children.an increase in group d salmonella isolates with high antimicrobial resistant rates is being seen in taiwan. this study aimed to determine the multidrug-resistant (mdr, more than three antibiotics) phenotype, genotype, and the correlation between the presence of class 1 integrons and its invasiveness of salmonella panama and salmonella enteritidis isolated from children.201223660223
the combination of crispr-mvlst and pfge provides increased discriminatory power for differentiating human clinical isolates of salmonella enterica subsp. enterica serovar enteritidis.salmonella enterica subsp. enterica serovar enteritidis (s. enteritidis) is a major cause of foodborne salmonellosis. rapid, efficient and accurate methods for identification are required to track specific strains of s. enteritidis during outbreaks of human salmonellosis. by exploiting the hypervariable nature of virulence genes and clustered regularly interspaced short palindromic repeats (crisprs), we previously developed a powerful sequence-based subtyping approach, designated crispr-mvlst. t ...201223498194
antimicrobial activity of oregano oil against antibiotic-resistant salmonella enterica on organic leafy greens at varying exposure times and storage temperatures.the objective of this study was to evaluate the effectiveness of oregano oil on four organic leafy greens (iceberg and romaine lettuces and mature and baby spinaches) inoculated with salmonella newport as a function of treatment exposure times as well as storage temperatures. leaf samples were washed, dip inoculated with s. newport (6-log cfu/ml) and dried. oregano oil was prepared at 0.1, 0.3, and 0.5% concentrations in sterile phosphate buffered saline (pbs). inoculated leaves were immersed in ...201223498188
performance of the aoac use-dilution method with targeted modifications: collaborative study.the u.s. environmental protection agency (epa), in collaboration with an industry work group, spearheaded a collaborative study designed to further enhance the aoac use-dilution method (udm). based on feedback from laboratories that routinely conduct the udm, improvements to the test culture preparation steps were prioritized. a set of modifications, largely based on culturing the test microbes on agar as specified in the aoac hard surface carrier test method, were evaluated in a five-laboratory ...201223451377
toward integrative genomics study of genetic resistance to salmonella and campylobacter intestinal colonization in fowl.salmonella enterica serotypes enteritidis and typhimurium and campylobacter jejuni are responsible for most cases of food poisoning in europe. these bacteria do not cause severe disease symptoms in chicken, but they are easily propagated by symptomless chicken carriers which cannot be easily isolated. this animal tolerance is detrimental to food safety. in this particular case, increasing animal's resistance is not sufficient, since some animals considered as resistant are able to carry bacteria ...201223412643
lactic acid bacteria and bifidobacteria attenuate the proinflammatory response in intestinal epithelial cells induced by salmonella enterica serovar typhimurium.inflammation is a physiological response to infections and tissue injury; however, abnormal immune responses can give rise to chronic inflammation and contribute to disease progression. various dietary components, including probiotic lactic acid bacteria and prebiotics, have the potential to modulate intestinal inflammatory responses. one factor in particular, the chemokine interleukin-8 (il-8, cxcl-8), is one of the major mediators of the inflammatory response. the purpose of this study was to ...201223391223
evaluation of salmonella enterica serovar typhimurium ttss-2 deficient fur mutant as safe live-attenuated vaccine candidate for immunocompromised mice.salmonella enterica serovar typhimurium has been extensively exploited as live attenuated vaccines (lav) which generally confers better protection than killed or subunit vaccines. however, many lav are limited by their inherent ability to access systemic organs in many of the vaccinated hosts, especially those which are immunocompromised. we evaluated the efficacy of a live-attenuated spi2-deficient (δssav) s. typhimurium vaccine candidate (mt13) that additionally devoids the ferric uptake regul ...201223284865
salmonella typhimurium's transthyretin-like protein is a host-specific factor important in fecal survival in chickens.the transthyretin-like protein (tlp) from salmonella enterica subspecies i is a periplasmic protein with high level structural similarity to a protein found in mammals and fish. in humans, the protein homologue, transthyretin, binds and carries retinol and thyroxine, and a series of other, unrelated aromatic compounds. here we show that the amino acid sequence of the tlp from different species, subspecies and serovars of the salmonella genus is highly conserved and demonstrate that the tlp gene ...201223284609
characterization of citrobacter sp. line 328 as a source of vi for a vi-crm(197) glycoconjugate vaccine against salmonella typhi.salmonella enterica serovar typhi is the causative agent of typhoid fever with over 22 million cases and over 200,000 deaths reported annually. a vaccine is much needed for use in young children and the novartis vaccines institute for global health (nvgh) is developing a conjugate vaccine which targets s. typhi vi capsular polysaccharide.201223277501
optimized microbial dna extraction from diarrheic stools.the detection of enteropathogens in stool specimens increasingly relies on the detection of specific nucleic acid sequences. we observed that such detection was hampered in diarrheic stool specimens and we set-up an improved protocol combining lyophilization of stools prior to a semi-automated dna extraction.201223273000
azithromycin and ciprofloxacin resistance in salmonella bloodstream infections in cambodian adults.salmonella enterica is a frequent cause of bloodstream infection (bsi) in asia but few data are available from cambodia. we describe salmonella bsi isolates recovered from patients presenting at sihanouk hospital centre of hope, phnom penh, cambodia (july 2007-december 2010).201223272255
sesbania grandiflora leaf extract mediated green synthesis of antibacterial silver nanoparticles against selected human pathogens.simple, effective and rapid approach for the green synthesis of silver nanoparticles (agnps) using leaf extract of sesbania grandiflora and their in vitro antibacterial activity against selected human pathogens has been demonstrated in the study. various instrumental techniques were adopted to characterize the synthesized agnps viz. uv-vis, ftir, xrd, tem, edx and afm. surface plasmon spectra for agnps are centered at 422 nm with dark brown color. the synthesized agnps were found to be spherical ...201223270884
spontaneous non-rdar mutations increase fitness of salmonella in plants.proliferation of human enteric pathogens within alternate hosts, like plants, leads to temporal changes in gene expression and also selects for the phenotypic variants of the enterics that are presumed to be more fit within plants. human enteric pathogens recovered from produce-borne outbreaks exhibit peculiar phenotypes, for example many of them do not display the rdar (red dry and rough) phenotype. the non-rdar phenotype results from mutations in cellulose and/or curli synthesis or regulation. ...201223760832
root internalization, transport and in-planta survival of salmonella enterica serovar newport in sweet basil.it is now acknowledged that food-borne pathogens present in the irrigation water or soil can become associated with crop plants in the field, penetrate internal plant tissues via the root, translocate and survive inside plants. only little information is available concerning interaction between enteric pathogens and plants. the present study evaluated the potential for contamination of the aromatic plant, sweet basil during cultivation, by salmonella enterica serovar newport. root internalizatio ...201223757144
evaluation of the strain variability of salmonella enterica acid and heat resistance.the inherent acid and heat resistances of 60 salmonella enterica strains were assessed in tryptone soy broth without dextrose acidified to ph 3.0 or heated at 57 °c. a total of 360 inactivation curves were generated. regarding the acid challenge experiments, the inactivation rate (kacid), estimated using the log-linear model, ranged from 0.47 to 3.25 h(-1). a log-linear model with a "survival tail" was used to describe the thermal inactivation of the strains, and the estimated inactivation rate ...201223541192
inactivation of salmonella enterica serovar typhimurium and escherichia coli o157:h7 in peanut butter cracker sandwiches by radio-frequency heating.a multistate outbreak of salmonella enterica serovar typhimurium recently occurred in the usa, which was traced back to various food products made with contaminated peanut butter. this study was conducted to investigate the efficacy of radio-frequency (rf) heating to inactivate s. typhimurium and escherichia coli o157:h7 in peanut butter cracker sandwiches using creamy and chunky commercial peanut butter and to determine the effect on quality by measuring color changes and sensory evaluation. sa ...201223498191
salmonella enterica serovar typhi in breast abscess: a case report. 201223455830
characterization of the elphis prophage from salmonella enterica serovar enteritidis strain lk5.phages are a primary driving force behind the evolution of bacterial pathogens by transferring a variety of virulence genes into their hosts. similar to other bacterial genomes, the salmonella enterica serovar enteritidis lk5 genome contains several regions that are homologous to phages. although genomic analyses demonstrated the presence of prophages, it was unable to confirm which phage elements within the genome were viable. genetic markers were used to tag one of the prophages in the genome ...201222247173
survival and growth of foodborne pathogens in minimally processed vegetables at 4 and 15 °c.we conducted this study to investigate the survival and growth of pathogens on fresh vegetables stored at 4 and 15 °c. vegetables (romaine lettuce, iceberg lettuce, perilla leaves, and sprouts) were inoculated with 4 pathogens (salmonella enterica serovar typhimurium, staphylococcus aureus, listeria monocytogenes, and escherichia coli o157:h7) and stored at 2 different temperatures for different periods of time (3, 6, 9, 12, and 15 d at 4 °c and 1, 2, 3, 5, and 7 d at 15 °c). populations of the ...201222260117
Resolving the contributions of the membrane-bound and periplasmic nitrate reductase systems to nitric oxide and nitrous oxide production in Salmonella enterica serovar Typhimurium.The production of cytotoxic nitric oxide (NO) and conversion into the neuropharmacological agent and potent greenhouse gas nitrous oxide (N2O) is linked with anoxic nitrate catabolism by Salmonella enterica serovar Typhimurium. Salmonella can synthesize two types of nitrate reductase: a membrane-bound form (Nar) and a periplasmic form (Nap). Nitrate catabolism was studied under nitrate-rich and nitrate-limited conditions in chemostat cultures following transition from oxic to anoxic conditions. ...201222039967
analysis of thic variants in the context of the metabolic network of salmonella enterica.in bacteria, the 4-amino-hydroxymethyl-2-methylpyrimidine (hmp) moiety of thiamine is synthesized from 5-aminoimidazole ribotide (air), a branch point metabolite of purine and thiamine biosynthesis. thic is a member of the radical s-adenosylmethionine (adomet) superfamily and catalyzes the complex chemical rearrangement of air to hmp-p. as reconstituted in vitro, the thic reaction requires adomet, air, and reductant. this study analyzed variants of thic in vivo and in vitro to probe the metaboli ...201222961850
multiplicity of salmonella entry mechanisms, a new paradigm for salmonella pathogenesis.the salmonella enterica species includes about 2600 diverse serotypes, most of which cause a wide range of food- and water-borne diseases ranging from self-limiting gastroenteritis to typhoid fever in both humans and animals. moreover, some serotypes are restricted to a few animal species, whereas other serotypes are able to infect plants as well as cold- and warm-blooded animals. an essential feature of the pathogenicity of salmonella is its capacity to cross a number of barriers requiring inva ...201223170225
quantification of bacterial indicators and zoonotic pathogens in dairy wastewater ponds.zoonotic pathogens in land-applied dairy wastewaters are a potential health risk. the occurrence and abundance of 10 pathogens and 3 fecal indicators were determined by quantitative real-time pcr (qpcr) in samples from 30 dairy wastewaters from southern idaho. samples tested positive for campylobacter jejuni, stx(1)- and eaea-positive escherichia coli, listeria monocytogenes, mycobacterium avium subsp. paratuberculosis, and salmonella enterica, with mean recoveries of genomic dna corresponding t ...201222983964
humanized tlr4/md-2 mice reveal lps recognition differentially impacts susceptibility to yersinia pestis and salmonella enterica.although lipopolysaccharide (lps) stimulation through the toll-like receptor (tlr)-4/md-2 receptor complex activates host defense against gram-negative bacterial pathogens, how species-specific differences in lps recognition impact host defense remains undefined. herein, we establish how temperature dependent shifts in the lipid a of yersinia pestis lps that differentially impact recognition by mouse versus human tlr4/md-2 dictate infection susceptibility. when grown at 37°c, y. pestis lps is hy ...201223071439
phosphate groups of lipid a are essential for salmonella enterica serovar typhimurium virulence and affect innate and adaptive immunity.lipid a is a key component of the outer membrane of gram-negative bacteria and stimulates proinflammatory responses via the toll-like receptor 4 (tlr4)-md2-cd14 pathway. its endotoxic activity depends on the number and length of acyl chains and its phosphorylation state. in salmonella enterica serovar typhimurium, removal of the secondary laurate or myristate chain in lipid a results in bacterial attenuation and growth defects in vitro. however, the roles of the two lipid a phosphate groups in b ...201222753374
immunological characterization of a gida mutant strain of salmonella for potential use in a live-attenuated vaccine.salmonella is often associated with gastrointestinal disease outbreaks in humans throughout the world due to the consumption of contaminated food. our previous studies have shown that deletion of glucose-inhibited division gene (gida) significantly attenuated salmonella enterica serovar typhimurium (stm) virulence in both in vitro and in vivo models of infection. most importantly, immunization with the gida mutant protected mice from a lethal dose challenge of wild-type stm. in this study, we fu ...201223194372
natural lysogenization and transduction in salmonella enterica serovar choleraesuis by bacteriophage p1.it has been reported that bacteriophage p1 injects dna into serovar choleraesuis without evidence of productive infection. however, we found that p1 generates progeny and is capable of transduction in serovar choleraesuis. this is not the case with other serovars of salmonella enterica we tested. therefore, p1 could play a role in serovar choleraesuis evolution and contribute to its genetic manipulation and analysis.201222995628
detection and identification of salmonella enterica, escherichia coli, and shigella spp. via pcr-electrospray ionization mass spectrometry: isolate testing and analysis of food samples.an assay to identify the common food-borne pathogens salmonella, escherichia coli, shigella, and listeria monocytogenes was developed in collaboration with ibis biosciences (a division of abbott molecular) for the plex-id biosensor system, a platform that uses electrospray ionization mass spectroscopy (esi-ms) to detect the base composition of short pcr amplicons. the new food-borne pathogen (fbp) plate has been experimentally designed using four gene segments for a total of eight amplicon targe ...201223001674
prevalence and relative risk of cronobacter spp., salmonella spp., and listeria monocytogenes associated with the body surfaces and guts of individual filth flies.although flies are important vectors of food-borne pathogens, there is little information to accurately assess the food-related health risk of the presence of individual flies, especially in urban areas. this study quantifies the prevalence and the relative risk of food-borne pathogens associated with the body surfaces and guts of individual wild flies. one hundred flies were collected from the dumpsters of 10 randomly selected urban restaurants. flies were identified using taxonomic keys before ...201222941079
structural insight into the clostridium difficile ethanolamine utilisation microcompartment.bacterial microcompartments form a protective proteinaceous barrier around metabolic enzymes that process unstable or toxic chemical intermediates. the genome of the virulent, multidrug-resistant clostridium difficile 630 strain contains an operon, eut, encoding a bacterial microcompartment with genes for the breakdown of ethanolamine and its utilisation as a source of reduced nitrogen and carbon. the c. difficile eut operon displays regulatory genetic elements and protein encoding regions in co ...201223144756
development of an improved selective and differential medium for isolation of salmonella spp.we describe an improved selective, differential, and cost-effective medium, xa medium, which contains d-arabinose, to facilitate the selective isolation of salmonella spp. the sensitivity and the specificity of xa medium were compared to those of xylose lysine desoxycholate agar (xld) using stock cultures and naturally contaminated food samples. xa medium and xld were evaluated with a total of 82 salmonella and 69 non-salmonella stock cultures. of 82 strains of salmonella spp. tested, 76 produce ...201222814469
multiplex t-rflp allows for increased target number and specificity: detection of salmonella enterica and six species of listeria in a single test.a multiplex t-rflp test was developed to detect and identify salmonella enterica and all six species of listeria inoculated into milk at minimal levels. extensive in silico analysis was used to design a fifteen-primer, six-amplimer methodology and in vitro application showed target organism dna, when amplified individually, yielded the predicted terminal restriction fragments (trfs) following digestion. non-target organisms were either not-amplified or yielded trfs which did not interfere with t ...201222937073
engineered protein nano-compartments for targeted enzyme localization.compartmentalized co-localization of enzymes and their substrates represents an attractive approach for multi-enzymatic synthesis in engineered cells and biocatalysis. sequestration of enzymes and substrates would greatly increase reaction efficiency while also protecting engineered host cells from potentially toxic reaction intermediates. several bacteria form protein-based polyhedral microcompartments which sequester functionally related enzymes and regulate their access to substrates and othe ...201222428024
complete fiber structures of complex trimeric autotransporter adhesins conserved in enterobacteria.trimeric autotransporter adhesins (taas) are modular, highly repetitive surface proteins that mediate adhesion to host cells in a broad range of gram-negative pathogens. although their sizes may differ by more than one order of magnitude, they all follow the same basic head-stalk-anchor architecture, where the head mediates adhesion and autoagglutination, the stalk projects the head from the bacterial surface, and the anchor provides the export function and attaches the adhesin to the bacterial ...201223213248
engineering of acetyl-coa metabolism for the improved production of polyhydroxybutyrate in saccharomyces cerevisiae.through metabolic engineering microorganisms can be engineered to produce new products and further produce these with higher yield and productivities. here, we expressed the bacterial polyhydroxybutyrate (phb) pathway in the yeast saccharomyces cerevisiae and we further evaluated the effect of engineering the formation of acetyl coenzyme a (acetyl-coa), an intermediate of the central carbon metabolism and precursor of the phb pathway, on heterologous phb production by yeast. we engineered the ac ...201223009357
the nsrr regulon in nitrosative stress resistance of salmonella enterica serovar typhimurium.nitric oxide (no·) is an important mediator of innate immunity. the facultative intracellular pathogen salmonella has evolved mechanisms to detoxify and evade the antimicrobial actions of host-derived no· produced during infection. expression of the no·-detoxifying flavohaemoglobin hmp is controlled by the no·-sensing transcriptional repressor nsrr and is required for salmonella virulence. in this study we show that nsrr responds to very low no· concentrations, suggesting that it plays a primary ...201222831173
the pduq enzyme is an alcohol dehydrogenase used to recycle nad+ internally within the pdu microcompartment of salmonella enterica.salmonella enterica uses a bacterial microcompartment (mcp) for coenzyme b(12)-dependent 1,2-propanediol (1,2-pd) utilization (pdu). the pdu mcp consists of a protein shell that encapsulates enzymes and cofactors required for metabolizing 1,2-pd as a carbon and energy source. here we show that the pduq protein of s. enterica is an iron-dependent alcohol dehydrogenase used for 1,2-pd catabolism. pduq is also demonstrated to be a new component of the pdu mcp. in addition, a series of in vivo and i ...201223077559
inhibition of bacterial virulence: drug-like molecules targeting the salmonella enterica phop response regulator.two-component signal transduction (tcst) is the predominant signaling scheme used in bacteria to sense and respond to environmental changes in order to survive and thrive. a typical tcst system consists of a sensor histidine kinase to detect external signals and an effector response regulator to respond to external changes. in the signaling scheme, the histidine kinase phosphorylates and activates the response regulator, which functions as a transcription factor to modulate gene expression. one ...201222339993
glycoconjugate vaccine strategies for protection against invasive salmonella infections.salmonella enterica serovars typhi and paratyphi a and b and certain non-typhoidal salmonella enterica (nts) serovars are important causes of invasive salmonella disease worldwide. nts serovars typhimurium and enteritidis typically cause gastroenteritis in healthy children and adults in industrialized countries but in certain hosts (e.g., young infants, the elderly, immunocompromised individuals) they also cause invasive infections. these two serovars also cause invasive disease in infants and y ...201222370510
the promoter architectural landscape of the salmonella phop regulon.the dna-binding protein phop controls virulence and mg²⁺ homeostasis in the gram-negative pathogen salmonella enterica serovar typhimurium. phop regulates expression of a large number of genes that differ both in their ancestry and in the biochemical functions and physiological roles of the encoded products. this suggests that phop-regulated genes are differentially expressed. to understand how a bacterial activator might generate varied gene expression behaviour, we investigated the cis-acting ...201222435712
a naturally occurring single nucleotide polymorphism in the salmonella spi-2 type iii effector srfh/ssei controls early extraintestinal dissemination.cd18 expressing phagocytes associated with the gastro-intestinal (gi) epithelium can shuttle salmonella directly into the bloodstream within a few minutes following microbial ingestion. we have previously demonstrated that salmonella controls the cd18 pathway to deeper tissue, manipulating the migratory properties of infected cells as an unappreciated component of its pathogenesis. we have observed that one type iii effector, srfh (also called ssei) that salmonella secretes into infected phagocy ...201223028876
invasive non-typhoidal salmonella disease: an emerging and neglected tropical disease in africa.invasive strains of non-typhoidal salmonellae have emerged as a prominent cause of bloodstream infection in african adults and children, with an associated case fatality of 20-25%. the clinical presentation of invasive non-typhoidal salmonella disease in africa is diverse: fever, hepatosplenomegaly, and respiratory symptoms are common, and features of enterocolitis are often absent. the most important risk factors are hiv infection in adults, and malaria, hiv, and malnutrition in children. a dis ...201222587967
type vi secretion system-associated gene clusters contribute to pathogenesis of salmonella enterica serovar typhimurium.the enteropathogen salmonella enterica serovar typhimurium employs a suite of tightly regulated virulence factors within the intracellular compartment of phagocytic host cells resulting in systemic dissemination in mice. a type vi secretion system (t6ss) within salmonella pathogenicity island 6 (spi-6) has been implicated in this process; however, the regulatory inputs and the roles of noncore genes in this system are not well understood. here we describe four clusters of noncore t6ss genes in s ...201222493086
a glycine betaine importer limits salmonella stress resistance and tissue colonization by reducing trehalose production.mechanisms by which salmonella establish chronic infections are not well understood. microbes respond to stress by importing or producing compatible solutes, small molecules that stabilize proteins and lipids. the salmonella locus opuabcd (also called opuc) encodes a predicted importer of the compatible solute glycine betaine. under stress conditions, if glycine betaine cannot be imported, salmonella enterica produce the disaccharide trehalose, a highly effective compatible solute. we demonstrat ...201222375627
srfj, a salmonella type iii secretion system effector regulated by phop, rcsb, and iolr.virulence-related type iii secretion systems are present in many gram-negative bacterial pathogens. these complex devices translocate proteins, called effectors, from the bacterium into the eukaryotic host cell. here, we identify the product of srfj, a salmonella enterica serovar typhimurium gene regulated by ssrb, as a new substrate of the type iii secretion system encoded by salmonella pathogenicity island 2. the n-terminal 20-amino-acid segment of srfj was recognized as a functional secretion ...201222661691
functional and computational analysis of amino acid patterns predictive of type iii secretion system substrates in pseudomonas syringae.bacterial type iii secretion systems (t3sss) deliver proteins called effectors into eukaryotic cells. although n-terminal amino acid sequences are required for translocation, the mechanism of substrate recognition by the t3ss is unknown. almost all actively deployed t3ss substrates in the plant pathogen pseudomonas syringae pathovar tomato strain dc3000 possess characteristic patterns, including (i) greater than 10% serine within the first 50 amino acids, (ii) an aliphatic residue or proline at ...201222558318
caspase-1 activity is required to bypass macrophage apoptosis upon salmonella infection.here we report awp28, an activity-based probe that can be used to biochemically monitor caspase-1 activation in response to proinflammatory stimuli. using awp28, we show that apoptosis is triggered upon salmonella enterica var. typhimurium infection in primary mouse bone marrow macrophages lacking caspase-1. furthermore, we report that upon salmonella infection, inflammasome-mediated caspase-1 activity is required to bypass apoptosis in favor of proinflammatory pyroptotic cell death.201222797665
differential biofilm formation and chemical disinfection resistance of sessile cells of listeria monocytogenes strains under monospecies and dual-species (with salmonella enterica) conditions.this study aimed to investigate the possible influence of bacterial intra- and interspecies interactions on the ability of listeria monocytogenes and salmonella enterica to develop mixed-culture biofilms on an abiotic substratum, as well as on the subsequent resistance of sessile cells to chemical disinfection. initially, three strains from each species were selected and left to attach and form biofilms on stainless steel (ss) coupons incubated at 15°c for 144 h, in periodically renewable trypto ...201222307304
functional dissection of ssef, a membrane-integral effector protein of intracellular salmonella enterica.during intracellular life, the bacterial pathogen salmonella enterica translocates a complex cocktail of effector proteins by means of the spi2-encoded type iii secretions system. the effectors jointly modify the endosomal system and vesicular transport in host cells. ssef and sseg are two effectors encoded by genes within salmonella pathogenicity island 2 and both effector associate with endosomal membranes and microtubules and are involved in the formation of salmonella-induced filaments. our ...201222529968
the dub-ious lack of alis in salmonella infection: a salmonella deubiquitinase regulates the autophagy of protein aggregates.ubiquitinated aggregates are formed in eukaryotic cells in response to several external stimuli, including exposure to bacterial lipopolysaccharide (lps). although salmonella enterica serovar typhimurium (s. typhimurium) lps has been shown to induce aggresome-like induced structures (alis) in macrophages, these have not been described in s. typhimurium-infected macrophages. given that lps is present in infection, this suggests that s. typhimurium might suppress the formation of alis. we found th ...201222931829
type 1 interferon-associated necroptosis: a novel mechanism for salmonella enterica typhimurium to induce macrophage death. 201223147719
the salmonella deubiquitinase ssel inhibits selective autophagy of cytosolic aggregates.cell stress and infection promote the formation of ubiquitinated aggregates in both non-immune and immune cells. these structures are recognised by the autophagy receptor p62/sequestosome 1 and are substrates for selective autophagy. the intracellular growth of salmonella enterica occurs in a membranous compartment, the salmonella-containing vacuole (scv), and is dependent on effectors translocated to the host cytoplasm by the salmonella pathogenicity island-2 (spi-2) encoded type iii secretion ...201222719249
human genome-wide rnai screen for host factors that modulate intracellular salmonella growth.salmonella enterica is a bacterial pathogen of humans that can proliferate within epithelial cells as well as professional phagocytes of the immune system. while much has been learned about the microbial genes that influence the infectious process through decades of intensive research, relatively little is known about the host factors that affect infection. we performed a genome-wide sirna screen to identify host genes that salmonella enterica serovar typhimurium (s. typhimurium) utilizes to fac ...201222701604
salmonella enterica: a surprisingly well-adapted intracellular lifestyle.the infectious intracellular lifestyle of salmonella enterica relies on the adaptation to nutritional conditions within the salmonella-containing vacuole (scv) in host cells. we summarize latest results on metabolic requirements for salmonella during infection. this includes intracellular phenotypes of mutant strains based on metabolic modeling and experimental tests, isotopolog profiling using (13)c-compounds in intracellular salmonella, and complementation of metabolic defects for attenuated m ...201222563326
functional analysis of bacillus subtilis genes involved in the biosynthesis of 4-thiouridine in trna.thii has been identified as an essential enzyme involved in the biosynthesis of thiamine and the trna thionucleoside modification, 4-thiouridine. in escherichia coli and salmonella enterica, thii acts as a sulfurtransferase, receiving the sulfur donated from the cysteine desulfurase iscs and transferring it to the target molecule or additional sulfur carrier proteins. however, in bacillus subtilis and most species from the firmicutes phylum, thii lacks the rhodanese domain that contains the site ...201222773787
identification of a third osmoprotectant transport system, the osmu system, in salmonella enterica.the growth of salmonella enterica serovar typhimurium mutants lacking the prop and prou osmoprotectant transport systems is stimulated by glycine betaine in high-osmolarity media, suggesting that this organism has an additional osmoprotectant transport system. bioinformatic analysis revealed that the genome of this organism contains a hitherto-unidentified operon, designated osmu, consisting of four genes whose products show high similarity to abc-type transport systems for osmoprotectants in ot ...201222609924
a trade-off between the fitness cost of functional integrases and long-term stability of integrons.horizontal gene transfer (hgt) plays a major role in bacterial microevolution as evident from the rapid emergence and spread of antimicrobial drug resistance. few studies have however addressed the population dynamics of newly imported genetic elements after hgt. here, we show that newly acquired class-1 integrons from salmonella enterica serovar typhimurium and acinetobacter baumannii, free of associated transposable elements, strongly reduce host fitness in acinetobacter baylyi. insertional in ...201223209414
functional analysis of the genes encoding diaminopropionate ammonia lyase in escherichia coli and salmonella enterica serovar typhimurium.diaminopropionate ammonia lyase (dapal) is a pyridoxal-5'phosphate (plp)-dependent enzyme that catalyzes the conversion of diaminopropionate (dap) to pyruvate and ammonia and plays an important role in cell metabolism. we have investigated the role of the ygex gene of escherichia coli k-12 and its ortholog, stm1002, in salmonella enterica serovar typhimurium lt2, presumed to encode dapal, in the growth kinetics of the bacteria. while salmonella typhimurium lt2 could grow on dl-dap as a sole carb ...201222904288
effect of systemic infection induced by pseudomonas aeruginosa on the brain uptake of colistin in mice.in view of reports of colistin-induced neurotoxicity in infected patients, the aim of this study was to assess whether the integrity of the blood-brain barrier (bbb) and the brain uptake of colistin are altered in the presence of systemic pseudomonas aeruginosa infection. bacteremia was confirmed 8 h after intramuscular administration of p. aeruginosa atcc 27853 to swiss outbred mice, at which time a single subcutaneous dose of colistin sulfate (40 mg/kg of body weight) or an intravenous dose of ...201222850514
colistin resistance in escherichia coli and salmonella enterica strains isolated from swine in brazil.reports about acquired resistance to colistin in different bacteria species are increasing, including e. coli of animal origin, but reports of resistance in wild s. enterica of different serotypes from swine are not found in the literature. results obtained with one hundred and twenty-six e. coli strains from diseased swine and one hundred and twenty-four s. enterica strains from diseased and carrier swine showed a frequency of 6.3% and 21% of colistin-resistant strains, respectively. when compa ...201222973166
impact of antibiotic mic on infection outcome in patients with susceptible gram-negative bacteria: a systematic review and meta-analysis.the objective of this study was to analyze the impact of mic values within the susceptible range of antibiotics on the outcomes of patients with gram-negative infections. the pubmed and scopus electronic databases were searched. we identified 13 articles (1,469 patients) that studied the impact of antibiotic mics on the outcomes of infections; β-lactams were studied in 10 of them. infections due to salmonella enterica strains with high fluoroquinolone mics were associated with more treatment fai ...201222615292
factors associated with encephalopathy in patients with salmonella enterica serotype typhi bacteremia presenting to a diarrheal hospital in dhaka, bangladesh.to characterize clinical correlates of typhoid fever-associated encephalopathy, we performed a retrospective chart review of patients with salmonella enterica serotype typhi bacteremia who were hospitalized at the international centre for diarrhoeal disease research, bangladesh, from february of 2009 to june of 2011. of 207 patients bacteremic with salmonella typhi who were ≥ 5 years of age, we identified 43 (21%) patients with encephalopathy. univariate analysis revealed that patients with ence ...201222492156
crosstalk between virulence loci: regulation of salmonella enterica pathogenicity island 1 (spi-1) by products of the std fimbrial operon.invasion of intestinal epithelial cells is a critical step in salmonella infection and requires the expression of genes located in salmonella pathogenicity island 1 (spi-1). a key factor for spi-1 expression is dna adenine (dam) methylation, which activates synthesis of the spi-1 transcriptional activator hild. dam-dependent regulation of hild is postranscriptional (and therefore indirect), indicating the involvement of unknown cell functions under dam methylation control. a genetic screen has i ...201222291968
a connecter-like factor, caca, links rssb/rpos and the cpxr/cpxa two-component system in salmonella.bacteria integrate numerous environmental stimuli when generating cellular responses. increasing numbers of examples describe how one two-component system (tcs) responds to signals detected by the sensor of another tcs. however, the molecular mechanisms underlying this phenomenon remain poorly defined.201223031642
reciprocal control between a bacterium's regulatory system and the modification status of its lipopolysaccharide.gram-negative bacteria often modify their lipopolysaccharide (lps), thereby increasing resistance to antimicrobial agents and avoidance of the host immune system. however, it is unclear how bacteria adjust the levels and activities of lps-modifying enzymes in response to the modification status of their lps. we now address this question by investigating the major regulator of lps modifications in salmonella enterica. we report that the pmra/pmrb system controls expression of a membrane peptide t ...201222921935
accessibility and conservation: general features of bacterial small rna-mrna interactions?bacterial small rnas (srnas) are a class of structural rnas that often regulate mrna targets via post-transcriptional base pair interactions. we determined features that discriminate functional from non-functional interactions and assessed the influence of these features on genome-wide target predictions. for this purpose, we compiled a set of 71 experimentally verified srna-target pairs from escherichia coli and salmonella enterica. furthermore, we collected full-length 5' untranslated regions ...201222767260
automated pangenomic analysis in target selection for pcr detection and identification of bacteria by use of ssgenefinder webserver and its application to salmonella enterica serovar typhi.with the advent of high-throughput dna sequencing, more than 4,000 bacterial genomes have been sequenced and are publicly available. we report a user-friendly web platform, ssgenefinder webserver (http://147.8.74.24/ssgenefinder/), which is updated weekly for the automated pangenomic selection of specific targets for direct pcr detection and the identification of clinically important bacteria without the need of gene sequencing. to apply the ssgenefinder webserver for identifying specific target ...201222442318
polyfunctional cd4+ t cell responses to immunodominant epitopes correlate with disease activity of virulent salmonella.salmonella enterica serovars are intracellular bacteria capable of causing typhoid fever and gastroenteritis of significant morbidity and mortality worldwide. current prophylactic and therapeutic treatment is hampered by the emergence of multidrug-resistant (mdr) strains of salmonella, and vaccines provide only temporal and partial protection in vaccinees. to develop more effective salmonella vaccines, it is important to understand the development of protective adaptive immunity to virulent salm ...201222912884
evolution of the metabolic and regulatory networks associated with oxygen availability in two phytopathogenic enterobacteria.dickeya dadantii and pectobacterium atrosepticum are phytopathogenic enterobacteria capable of facultative anaerobic growth in a wide range of o2 concentrations found in plant and natural environments. the transcriptional response to o2 remains under-explored for these and other phytopathogenic enterobacteria although it has been well characterized for animal-associated genera including escherichia coli and salmonella enterica. knowledge of the extent of conservation of the transcriptional respo ...201222439737
characterization of salmonella type iii secretion hyper-activity which results in biofilm-like cell aggregation.we have previously reported the cloning of the salmonella enterica serovar typhimurium spi-1 secretion system and the use of this clone to functionally complement a δspi-1 strain for type iii secretion activity. in the current study, we discovered that s. typhimurium cultures containing cloned spi-1 display an adherent biofilm and cell clumps in the media. this phenotype was associated with hyper-expression of spi-1 type iii secretion functions. the biofilm and cell clumps were associated with c ...201222412985
mapping the aetiology of non-malarial febrile illness in southeast asia through a systematic review--terra incognita impairing treatment policies.an increasing use of point of care diagnostic tests that exclude malaria, coupled with a declining malaria burden in many endemic countries, is highlighting the lack of ability of many health systems to manage other causes of febrile disease. a lack of knowledge of distribution of these pathogens, and a lack of screening and point-of-care diagnostics to identify them, prevents effective management of these generally treatable contributors to disease burden. while prospective data collection is v ...201222970193
structure, diversity, and mobility of the salmonella pathogenicity island 7 family of integrative and conjugative elements within enterobacteriaceae.integrative and conjugative elements (ices) are self-mobile genetic elements found in the genomes of some bacteria. these elements may confer a fitness advantage upon their host bacteria through the cargo genes that they carry. salmonella pathogenicity island 7 (spi-7), found within some pathogenic strains of salmonella enterica, possesses features indicative of an ice and carries genes implicated in virulence. we aimed to identify and fully analyze ices related to spi-7 within the genus salmone ...201222247511
a constitutively mannose-sensitive agglutinating salmonella enterica subsp. enterica serovar typhimurium strain, carrying a transposon in the fimbrial usher gene stbc, exhibits multidrug resistance and flagellated phenotypes.static broth culture favors salmonella enterica subsp. enterica serovar typhimurium to produce type 1 fimbriae, while solid agar inhibits its expression. a transposon inserted in stbc, which would encode an usher for stb fimbriae of a non-flagellar salmonella enterica subsp. enterica serovar typhimurium lb5010 strain, conferred it to agglutinate yeast cells on both cultures. rt-pcr revealed that the expression of the fimbrial subunit gene fima, and fimz, a regulatory gene of fima, were both incr ...201222654583
antisense transcription is pervasive but rarely conserved in enteric bacteria.noncoding rnas, including antisense rnas (asrnas) that originate from the complementary strand of protein-coding genes, are involved in the regulation of gene expression in all domains of life. recent application of deep-sequencing technologies has revealed that the transcription of asrnas occurs genome-wide in bacteria. although the role of the vast majority of asrnas remains unknown, it is often assumed that their presence implies important regulatory functions, similar to those of other nonco ...201222872780
recent findings about the yersinia enterocolitica phage shock protein response.the phage shock protein (psp) system is a conserved extracytoplasmic stress response in bacteria that is essential for virulence of the human pathogen yersinia enterocolitica. this article summarizes some recent findings about y. enterocolitica psp system function. increased psp gene expression requires the transcription factor pspf, but under non-inducing conditions pspf is inhibited by an interaction with another protein, pspa, in the cytoplasm. a psp-inducing stimulus causes pspa to relocate ...201222367931
structural characterization of the plig lysozyme inhibitor family.several gram-negative bacteria protect themselves against the lytic action of host lysozymes by producing specific proteinaceous inhibitors. so far, four different families of lysozyme inhibitors have been identified including ivy (inhibitor of vertebrate lysozyme), mlic/plic (membrane associated/periplasmic inhibitor of c-type lysozyme), plii and plig (periplasmic inhibitors of i- and g-type lysozymes, respectively). here we provide the first crystallographic description of the plig family. cry ...201222634186
emergence and stability of high-pressure resistance in different food-borne pathogens.high hydrostatic pressure (hhp) processing is becoming a valuable nonthermal food pasteurization technique, although there is reasonable concern that bacterial hhp resistance could compromise the safety and stability of hhp-processed foods. while the degree of natural hhp resistance has already been shown to vary greatly among and within bacterial species, a still unresolved question remains as to what extent different food-borne pathogens can actually develop hhp resistance. in this study, we t ...201222344661
ssef, a type iii effector protein from the mammalian pathogen salmonella enterica, requires resistance-gene-mediated signalling to activate cell death in the model plant nicotiana benthamiana.type iii effector proteins (t3es) of many gram-negative pathogenic bacteria manipulate highly conserved cellular processes, indicating conservation in virulence mechanisms during the infection of hosts of divergent evolutionary origin. in order to identify conserved effector functions, we used a cross-kingdom approach in which we expressed selected t3es from the mammalian pathogen salmonella enterica in leaves of nicotiana benthamiana and searched for possible virulence or avirulence phenotypes. ...201222471508
antimicrobial and synergistic effects of silver nanoparticles synthesized using soil fungi of high altitudes of eastern himalaya.fifty three fungi isolated from soils of different microhabitats of eastern himalayan range (3,400~3,600 msl) were screened for mycosynthesis of silver nanaoparticles (agnps) and their efficacy as antimicrobials were assessed in combination with commonly used antibiotics. three isolates aspergillus terreus sp5, paecilomyces lilacinus sf1 and fusarium sp. mp5 identified based on morphological and 18s rrna gene sequences were found to synthesize agnps. these nanoparticles were characterized by vis ...201222783131
characterization of lactic acid bacteria from naturally-fermented manzanilla aloreña green table olives.manzanilla aloreña (or aloreña) table olives are naturally fermented traditional green olives with a denomination of protection (dop). the aim of this study was to search for lactic acid bacteria (lab) with technological properties of interest for possible inclusion in a starter or protective culture preparation or also as probiotics. a collection of 144 lab obtained from aloreña green table olives naturally-fermented by four small-medium enterprises (smes) from málaga (spain), including lactoba ...201222986194
antibacterial effect of phosphates and polyphosphates with different chain length.the aim of this study was to monitor the antibacterial effect of seven phosphate salts on selected strains of gram-negative and gram-positive bacteria, which could be considered responsible for food-borne diseases (bacillus cereus, bacillus subtilis, enterococcus faecalis, micrococcus luteus, staphylococcus aureus, citrobacter freundii, escherichia coli, proteus mirabilis, salmonella enterica ser. enteritidis and pseudomonas aeruginosa). for these purposes, phosphates differing in chain length w ...201222934995
probiotic activity of a bacterial strain isolated from ancient permafrost against salmonella infection in mice.bacillus cereus strain f, collected from relict permafrost located in siberia, was analyzed for probiotic activity in the mouse salmonella enterica model. viable bacterial cells were found in frozen soils taken at mammoth mountain in yakutia from a depth below the level of seasonal thawing. geological data indicated the absence of a thawing within millions of years of deposited soils, which helped to ensure the ancient origin of our sample. according to dna analysis, bacterial cells collected fr ...201226782040
antibiotic resistance and probiotic properties of dominant lactic microflora from tungrymbai, an ethnic fermented soybean food of india.the present investigation was conducted to assess lactic acid bacteria present in traditionally fermented food of ethnic tribes in india for probiotic properties, antibacterial activity, and antibiotic tolerance behavior. enterococcus sp., lactobacillus sp., and lactococcus sp. showed antibacterial activity against bacillus cereus mtcc 430, staphylococcus aureus subsp. aureus mtcc 740, and salmonella enterica ser. paratyphi a mtcc 735. lactococcus sp. and lactobacillus sp. could tolerate acidic ...201222752919
identification of a new bacillus licheniformis strain producing a bacteriocin-like substance.the emergence of antibiotic resistance has spurred a great number of studies for development of new antimicrobials in the past decade. the purpose of this study was to screen environmental samples for bacillus strains producing potent antimicrobial agents. a new strain, which showed strong antimicrobial activity against staphylococcus aureus and salmonella enterica ser. pullorum, was isolated from soil and designated as b116. this new isolate was identified as bacillus licheniformis by morpholog ...201222752909
antimicrobial effects of silver nanoparticles against bacterial cells adhered to stainless steel surfaces.given the increasing number of antibiotic-resistant bacteria and the need to synthesize new antimicrobials, silver has attracted interest in the scientific community because of its recognized antimicrobial activity. this study aimed to evaluate the antimicrobial effects of silver nanoparticles (np) obtained by a new method and tested at concentrations of 6 μg/ml and 60 μg/ml against the species staphylococcus aureus, listeria innocua, salmonella choleraesuis, pseudomonas aeruginosa, escherichia ...201222488058
controlling salmonella infection in weanling pigs through water delivery of direct-fed microbials or organic acids: part ii. effects on intestinal histology and active nutrient transport.the objective of this study was to evaluate the effects of water-delivered, direct-fed microbials (dfm) or organic acids on intestinal morphology and active nutrient absorption in weanling pigs after deliberate salmonella infection. pigs (n = 88) were weaned at 19 ± 2 d of age and assigned to 1 of the following treatments, which were administered for 14 d: 1) control diet; 2) control diet + dfm (enterococcus faecium, bacillus subtilis, and bacillus licheniformis) in drinking water at 10(9) cfu/l ...201222344321
effects of parabens and isothiazolinone on the microbiological quality of baby shampoo: the challenge test.an in vitro microbial challenge test has been developed to predict the likelihood of consumer contamination of baby shampoo. four preservatives were tested in our study: the parbens medcide d, medcide pb, sepicide hb. and isothiazolinone methylisothiazolinone/chloromethylisothiazolinone [mi/mci]. these preservatives were tested separately and in combination. the challenge test involved inoculating the product with micrococcus luteus, staphylococcus aureus, escherichia coli, salmonella enterica, ...201223007105
diversity and biological activities of endophytic fungi of emblica officinalis, an ethnomedicinal plant of india.in the present study, an attempt to evaluate the antimicrobial and antioxidant activity of fungal endophytes inhabiting emblica officinalis has been made keeping in view the medicinal importance of the selected host plant in indian traditional practices. a total of four endophytic fungi belonging to phylum ascomycetes were isolated from different parts of the plant which were characterized morphologically and by using rdna-internal transcribed spacer. the most frequently isolated endophyte was p ...201222783128
structures of a unique o-polysaccharide of edwardsiella tarda pcm 1153 containing an amide of galacturonic acid with 2-aminopropane-1,3-diol and an abequose-containing o-polysaccharide shared by e. tarda pcm 1145, pcm 1151 and pcm 1158.lipopolysaccharides of four strains of edwardsiella tarda were degraded by mild acid hydrolysis, and the released o-polysaccharides were isolated by gpc and studied by sugar and methylation analyses along with (1)h and (13)c nmr spectroscopy, including 2d (1)h, (1)h cosy, tocsy, roesy, (1)h, (13)c hmbc, hsqc and hsqc-tocsy experiments. the o-polysaccharide from e. tarda pcm 1153 was found to contain d-gala, d-glcnac, d-gal and 2-amino-1,3-propanediol (gron). in the tetrasaccharide repeating unit ...201222578768
a genomic island in salmonella enterica ssp. salamae provides new insights on the genealogy of the locus of enterocyte effacement.the genomic island encoding the locus of enterocyte effacement (lee) is an important virulence factor of the human pathogenic escherichia coli. lee typically encodes a type iii secretion system (t3ss) and secreted effectors capable of forming attaching and effacing lesions. although prominent in the pathogenic e. coli such as serotype o157:h7, lee has also been detected in citrobacter rodentium, e. albertii, and although not confirmed, it is likely to also be in shigella boydii. previous phyloge ...201222860002
quantitative proteomic analysis of type iii secretome of enteropathogenic escherichia coli reveals an expanded effector repertoire for attaching/effacing bacterial pathogens.type iii secretion systems are central to the pathogenesis and virulence of many important gram-negative bacterial pathogens, and elucidation of the secretion mechanism and identification of the secreted substrates are critical to our understanding of their pathogenic mechanisms and developing potential therapeutics. stable isotope labeling with amino acids in cell culture-based mass spectrometry is a quantitative and highly sensitive proteomics tool that we have previously used to successfully ...201222661456
discovery of an archetypal protein transport system in bacterial outer membranes.bacteria have mechanisms to export proteins for diverse purposes, including colonization of hosts and pathogenesis. a small number of archetypal bacterial secretion machines have been found in several groups of bacteria and mediate a fundamentally distinct secretion process. perhaps erroneously, proteins called 'autotransporters' have long been thought to be one of these protein secretion systems. mounting evidence suggests that autotransporters might be substrates to be secreted, not an autonom ...201222466966
activation of type iii interferon genes by pathogenic bacteria in infected epithelial cells and mouse placenta.bacterial infections trigger the expression of type i and ii interferon genes but little is known about their effect on type iii interferon (ifn-λ) genes, whose products play important roles in epithelial innate immunity against viruses. here, we studied the expression of ifn-λ genes in cultured human epithelial cells infected with different pathogenic bacteria and in the mouse placenta infected with listeria monocytogenes. we first showed that in intestinal lovo cells, induction of ifn-λ genes ...201222720036
glutathione deficiency in type 2 diabetes impairs cytokine responses and control of intracellular bacteria.individuals with type 2 diabetes are at increased risk of acquiring melioidosis, a disease caused by burkholderia pseudomallei infection. although up to half of melioidosis patients have underlying diabetes, the mechanisms involved in this increased susceptibility are unknown. we found that b. pseudomallei-infected pbmcs from diabetic patients were impaired in il-12p70 production, which resulted in decreased ifn-γ induction and poor bacterial killing. the defect was specific to the il-12-ifn-γ a ...201222546856
pathogenicity of salmonella enterica in caenorhabditis elegans relies on disseminated oxidative stress in the infected host.feeding caenorhabditis elegans with salmonella enterica serovar typhimurium significantly shortens the lifespan of the nematode. s. typhimurium-infected c. elegans, stained with 2',7'-dichlorodihydrofluorescein diacetate which fluoresces upon exposure to reactive oxygen species, revealed intestinal luminal staining that along with the time of infection progressed to a strong staining in the hypodermal tissues of the nematode. still, we could not detect invasion beyond the nematode's intestinal e ...201223028994
long-amplicon propidium monoazide-pcr enumeration assay to detect viable campylobacter and salmonella.the effect of amplicon length on the ability of propidium monoazide-pcr (pma-pcr) to reliably quantify viable cells without interference from dead cells was tested on heat- and ultraviolet (uv)-killed salmonella enterica and campylobacter jejuni, two important enteric pathogens of concern in environmental, food and clinical samples.201222747901
campylobacter jejuni is highly susceptible to killing by chicken host defense peptide cathelicidin-2 and suppresses intestinal cathelicidin-2 expression in young broilers.little is known about the interactions of chicken host defense peptides (hdps) with campylobacter jejuni in young chicks. to examine the role of the chicken hdp, cathelicidin-2 (cath-2) in host-pathogen interactions we challenged 4-day-old ross 308 broilers with a chicken-derived c. jejuni isolate (ws356) and used the chicken pathogen salmonella enterica enteritidis phage type 4 (fgt1) as a reference. immunohistochemical staining was used to localize cath-2, c. jejuni and salmonella enteritidis. ...201222728124
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