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salmonella enterica serovar typhi and the pathogenesis of typhoid fever.salmonella enterica serovar typhi, the cause of typhoid, is host restricted to humans. s. typhi has a monophyletic population structure, indicating that typhoid in humans is a relatively new disease. antimicrobial usage is reshaping the current s. typhi global population and may be driving the emergence of a specific haplotype, h58, that is well adapted to transmission in modern settings and is able to resist antimicrobial killing more efficiently than other s. typhi. evidence gathered through g ...201425208300
insertion of a 59 amino acid peptide in salmonella typhimurium membrane results in loss of virulence in mice.we demonstrated previously that expression of a single trans-membrane region of the δ(12) -desaturase gene of synechocystis sp. pcc 6803 in salmonella enterica serovar typhimurium (salmonella typhimurium) altered the membrane physical state of this pathogen, induced a significant change in the pattern of mrna transcription of major heat shock genes, and inhibited pathogen growth inside murine macrophages. in this study, we demonstrate that injection of the modified salmonella strain [stm(pbad200 ...201425208333
age-dependent enterocyte invasion and microcolony formation by salmonella.the coordinated action of a variety of virulence factors allows salmonella enterica to invade epithelial cells and penetrate the mucosal barrier. the influence of the age-dependent maturation of the mucosal barrier for microbial pathogenesis has not been investigated. here, we analyzed salmonella infection of neonate mice after oral administration. in contrast to the situation in adult animals, we observed spontaneous colonization, massive invasion of enteroabsorptive cells, intraepithelial prol ...201425210785
the orphan regulator reid of salmonella enterica is essential for myo-inositol utilization.in salmonella enterica serovar typhimurium (s. typhimurium), the genomic island gei4417/4436 is responsible for the utilization of myo-inositol (mi) as carbon and energy source. here, we report the characterization of a novel, island-encoded positive autoregulator termed reid (stm4423) that is specific to certain s. enterica strains and escherichia coli strain ed1a able to use mi. reid was essential for growth with this polyol and also contributed to s. typhimurium proliferation in swine caecum ...201425213016
prevalence and characterization of salmonella enterica in dried milk-related infant foods in shaanxi, china.the aim of this study was to investigate the existence and characteristics of salmonella enterica in dried milk-related infant foods. twenty-four (3.4%) of 705 samples, including 5 (2.0%) of 246 powdered infant formula, 18 (4.0%) of 445 infant rice cereal, and 1 (7.1%) of 14 other infant foods, were positive for salmonella. fifteen serotypes were identified in 40 salmonella isolates; salmonella duesseldorf (15.0%) and salmonella indiana (15.0%) were more frequently detected than other serotypes. ...201425218754
structure of a bacterial α2-macroglobulin reveals mimicry of eukaryotic innate immunity.alpha-2-macroglobulins (a2ms) are plasma proteins that trap and inhibit a broad range of proteases and are major components of the eukaryotic innate immune system. surprisingly, a2m-like proteins were identified in pathogenically invasive bacteria and species that colonize higher eukaryotes. bacterial a2ms are located in the periplasm where they are believed to provide protection to the cell by trapping external proteases through a covalent interaction with an activated thioester. here we report ...201425221932
characterization of variants of the pore-forming toxin clya from escherichia coli controlled by a redox switch.the α-pore-forming toxin cytolysin a (clya) is responsible for the hemolytic phenotype of several escherichia coli and salmonella enterica strains. clya is a soluble, 34 kda monomer that assembles into a dodecameric pore complex in the presence of membranes or detergent. the comparison of the x-ray structures of monomeric clya and the clya protomer in the pore complex revealed one of the largest conformational transitions observed so far in proteins, involving the structural rearrangement of mor ...201425222267
characterization of pseudomonas aeruginosa lpxt reveals dual positional lipid a kinase activity and co-ordinated control of outer membrane modification.gram-negative bacteria have evolved modification machinery to promote a dynamic outer membrane in response to a continually fluctuating environment. the kinase lpxt, for example, adds a phosphate group to the lipid a moiety of some gram-negatives including escherichia coli and salmonella enterica. lpxt activity is inhibited under conditions that compromise membrane integrity, resulting instead in the addition of positively charged groups to lipid a that increase membrane stability and provide re ...201425223756
cellular requirements for systemic control of salmonella enterica serovar typhimurium infections in mice.the rational design of vaccines requires an understanding of the contributions of individual immune cell subsets to immunity. with this understanding, targeted vaccine delivery approaches and adjuvants can be developed to maximize vaccine efficiency and to minimize side effects (s. h. e. kaufmann et al., immunity 33:555-577, 2010; t. ben-yedidia and r. arnon, hum. vaccines 1:95-101, 2005). we have addressed the contributions of different immune cell subsets and their ability to contribute to the ...201425225248
a novel, broad-range, ctxφ-derived stable integrative expression vector for functional studies.ctxφ, a filamentous vibriophage encoding cholera toxin, uses a unique strategy for its lysogeny. the single-stranded phage genome forms intramolecular base-pairing interactions between two inversely oriented xerc and xerd binding sites (xbs) and generates a functional phage attachment site, attp(+), for integration. the attp(+) structure is recognized by the host-encoded tyrosine recombinases xerc and xerd (xercd), which enables irreversible integration of ctxφ into the chromosome dimer resoluti ...201425225263
a community outbreak of salmonella enterica serotype typhimurium associated with an asymptomatic food handler in two local restaurants.between january and april 2012, the city of long beach department of health and human services investigated an outbreak involving 19 case patients who had tested positive for salmonella enterica serotype typhimurium with indistinguishable pulsed-field gel electrophoresis patterns. all cases were residents of or traveled to the city of long beach, california, during their incubation period, and the majority of patients reported eating at one of two restaurants in long beach. this article describe ...201425226780
saccharomyces boulardii prevention of the hepatic injury induced by salmonella enteritidis infection.salmonella enterica subsp. enterica serovar enteritidis (salmonella enteritidis) is the predominant cause of serovar-associated food-borne outbreaks in many countries and causes significant clinical symptoms of liver injury, enteritis, and diarrheal diseases. saccharomyces boulardii is used in clinical application for prophylaxis and the treatment of a variety of diseases caused by bacterial infection. we used a mouse model of salmonella enteritidis infection, which included pretreatment with s. ...201425231732
the effects of vaccination and immunity on bacterial infection dynamics in vivo.salmonella enterica infections are a significant global health issue, and development of vaccines against these bacteria requires an improved understanding of how vaccination affects the growth and spread of the bacteria within the host. we have combined in vivo tracking of molecularly tagged bacterial subpopulations with mathematical modelling to gain a novel insight into how different classes of vaccines and branches of the immune response protect against secondary salmonella enterica infectio ...201425233077
correction for rehman et al., high-quality draft whole-genome sequences of 162 salmonella enterica subsp. enterica serovar enteritidis strains isolated from diverse sources in canada. 201425237031
spi-23 of s. derby: role in adherence and invasion of porcine tissues.salmonella enterica serovars derby and mbandaka are isolated from different groups of livestock species in the uk. s. derby is predominantly isolated from pigs and turkeys and s. mbandaka is predominantly isolated from cattle and chickens. alignment of the genome sequences of two isolates of each serovar led to the discovery of a new putative salmonella pathogenicity island, spi-23, in the chromosome sequence of s. derby isolates. spi-23 is 37 kb in length and contains 42 orfs, ten of which are ...201425238397
bacteriophage p22 to challenge salmonella in foods.in this study we considered the influence of phage addition on the fate of salmonella enterica serovar typhimurium in different foods. phage p22 was applied to the following: liquid eggs, energy drinks, whole and skimmed milk, apple juice, chicken breast and chicken mince all spiked with its host, whose growth was monitored for 24 and 48 h at 4 °c. appreciable host inactivation, generally in the order of 2 log cycles, was achieved compared to phage-free controls in all food matrices when 10(4) u ...201425240138
a novel multiplex pcr for the simultaneous detection of salmonella enterica and shigella species.salmonella enterica and shigella species are commonly associated with food and water borne infections leading to gastrointestinal diseases. the present work was undertaken to develop a sensitive and reliable pcr based detection system for simultaneous detection of salmonella enterica and shigella at species level. for this the conserved regions of specific genes namely ipah1, ipah, wbgz, wzy and inva were targeted for detection of shigella genus, s. flexneri, s. sonnei, s. boydii and salmonella ...201425242957
the antimicrobial efficacy of lippia alba essential oil and its interaction with food ingredients.the objective of this study was to evaluate the antimicrobial potential of lippia alba essential oil (eola) and to investigate the effect of food ingredients on its efficacy. the antimicrobial potential of the oil was determined by the presence or absence of inhibition zones, minimum inhibitory concentration (mic) and minimum bactericidal concentration (mbc) against escherichia coli, listeria innocua, listeria monocytogenes, pseudomonas aeruginosa, salmonella choleraesuis and staphylococcus aure ...201425242961
arcobacter butzleri induces a pro-inflammatory response in thp-1 derived macrophages and has limited ability for intracellular survival.recent case reports have identified arcobacter (a.) butzleri to be another emerging pathogen of the family campylobacteraceae causing foodborne diseases. however, little is known about its interaction with the human immune system. as macrophages act as first defense against bacterial infections, we studied for the first time the impact of a. butzleri on human macrophages using thp-1 derived macrophages as an in vitro infection model. our investigations considered the inflammatory response, intra ...201425245281
monotreme lactation protein is highly expressed in monotreme milk and provides antimicrobial protection.monotremes (platypus and echidna) are the descendants of the oldest ancestor of all extant mammals distinguished from other mammals by mode of reproduction. monotremes lay eggs following a short gestation period and after an even briefer incubation period, altricial hatchlings are nourished over a long lactation period with milk secreted by nipple-less mammary patches located on the female's abdomen. milk is the sole source of nutrition and immune protection for the developing young until weanin ...201425245409
characterization of blatem-52-carrying plasmids of extended-spectrum-β-lactamase-producing salmonella enterica isolates from chicken meat with a common supplier in japan.the acquisition of resistance to cephalosporins among salmonella spp. is a major public health concern. this study identified clonal plasmids carrying bla(tem-52) from 10 salmonella enterica serovar infantis and manhattan isolates from retail chicken meats that originated from a common supplier in japan. whole-genome analyses of the representative plasmids, including pym4, revealed that they are 38 kb in size and that pym4 is identical to pdkx1 from beef in denmark, suggesting a global dissemina ...201425246394
the essential protein for bacterial flagella formation flgj functions as a β-n-acetylglucosaminidase.the flagellum is a major virulence factor of motile pathogenic bacteria. this structure requires more than 50 proteins for its biogenesis and function, one of which is flgj. homologs of flgj produced by the β- and γ-proteobacteria, such as salmonella enterica, vibrio spp., and both sphingomonas sp. and pseudomonas spp. are bifunctional, possessing an n-terminal domain responsible for proper rod assembly and a c-terminal domain possessing peptidoglycan lytic activity. despite the amount of resear ...201425248745
gastrointestinal microbiota-mediated control of enteric pathogens.the gastrointestinal (gi) microbiota is a complex community of microorganisms residing within the mammalian gastrointestinal tract. the gi microbiota is vital to the development of the host immune system and plays a crucial role in human health and disease. the composition of the gi microbiota differs immensely among individuals yet specific shifts in composition and diversity have been linked to inflammatory bowel disease, obesity, atopy, and susceptibility to infection. in this review, we desc ...201425251855
the structure and regulation of flagella in bacillus subtilis.bacterial flagellar motility is among the most extensively studied physiological systems in biology, but most research has been restricted to using the highly similar gram-negative species escherichia coli and salmonella enterica. here, we review the recent advances in the study of flagellar structure and regulation of the distantly related and genetically tractable gram-positive bacterium bacillus subtilis. b. subtilis has a thicker layer of peptidoglycan and lacks the outer membrane of the gra ...201425251856
red-mediated recombineering of salmonella enterica genomes.the mutagenesis of enterobacterial genomes using phage λ red recombinase functions is a rapid and versatile experimental tool. in addition to the rapid generation of deletions in the genome of salmonella enterica, variations of the method allow site-directed mutagenesis, generation of reporter fusions, generation of chimeric genes, or transplantation of regulatory elements directly in the chromosome. we describe the application of these approaches with focus on practical aspects and critical ste ...201525253248
generation and use of site-directed chromosomal cyaa' translational fusions in salmonella enterica.cyaa from bordetella pertussis is a calmodulin-dependent adenylate cyclase. fusions to the catalytic domain of cyaa (cyaa') are useful tools to detect translocation of type iii secretion system effectors from gram-negative pathogens like salmonella enterica. these fusions are usually generated using plasmids with strong promoters. here, we describe a protocol to insert the cyaa'-encoding sequence in a specific site in the bacterial chromosome in order to get a monocopy fusion whose expression is ...201525253250
applications of microscopy in salmonella research.salmonella enterica is a gram-negative enteropathogen that can cause localized infections, typically resulting in gastroenteritis, or systemic infection, e.g., typhoid fever, in humans and many other animals. understanding the mechanisms by which salmonella induces disease has been the focus of intensive research. this has revealed that salmonella invasion requires dynamic cross-talk between the microbe and host cells, in which bacterial adherence rapidly leads to a complex sequence of cellular ...201525253256
live cell imaging of intracellular salmonella enterica.during the intracellular phase of the pathogenic lifestyle, salmonella enterica massively alters the endosomal system of its host cells. two hallmarks are the remodeling of phagosomes into the salmonella-containing vacuole (scv) as a replicative niche, and the formation of tubular structures, such as salmonella-induced filaments (sifs). to study the dynamics and the fate of these salmonella-specific compartments, live cell imaging (lci) is a method of choice. in this chapter, we compare currentl ...201525253257
multiplex isothermal solid-phase recombinase polymerase amplification for the specific and fast dna-based detection of three bacterial pathogens.we report on the development of an on-chip rpa (recombinase polymerase amplification) with simultaneous multiplex isothermal amplification and detection on a solid surface. the isothermal rpa was applied to amplify specific target sequences from the pathogens neisseria gonorrhoeae, salmonella enterica and methicillin-resistant staphylococcus aureus (mrsa) using genomic dna. additionally, a positive plasmid control was established as an internal control. the four targets were amplified simultaneo ...201425253912
reorganization of the endosomal system in salmonella-infected cells: the ultrastructure of salmonella-induced tubular compartments.during the intracellular life of salmonella enterica, a unique membrane-bound compartment termed salmonella-containing vacuole, or scv, is formed. by means of translocated effector proteins, intracellular salmonella also induce the formation of extensive, highly dynamic membrane tubules termed salmonella-induced filaments or sif. here we report the first detailed ultrastructural analyses of the scv and sif by electron microscopy (em), em tomography and live cell correlative light and electron mi ...201425254663
a versatile and highly efficient method for scarless genome editing in escherichia coli and salmonella enterica.recently developed methods for genome editing in bacteria take advantage of the introduction of double-strand breaks by i-scei in a mutation cassette to select for cells in which homologous recombination has healed the break and introduced a desired mutation. this elegantly designed method did not work well in our hands for most genes.201425255806
co-occurrence of free-living protozoa and foodborne pathogens on dishcloths: implications for food safety.in the present study, the occurrence of free-living protozoa (flp) and foodborne bacterial pathogens on dishcloths was investigated. dishcloths form a potentially important source of cross-contamination with flp and foodborne pathogens in food-related environments. first various protocols for recovering and quantifying flp from dishcloths were assessed. the stomacher technique is recommended to recover flagellates and amoebae from dishcloths. ciliates, however, were more efficiently recovered us ...201425260173
thiouracil-forming bacteria identified and characterized upon porcine in vitro digestion of brassicaceae feed.in recent years, the frequent detection of the banned thyreostat thiouracil (tu) in livestock urine has been related to endogenous tu formation following digestion of glucosinolate-rich brassicaceae crops. recently, it was demonstrated that, upon in vitro digestion of brassicaceae, fecal bacteria induce tu detection in livestock (porcine livestock > bovines). therefore, the present study was intended to isolate and identify bacteria involved in this intestinal tu formation upon brassicaceae dige ...201425261511
sensitization of intracellular salmonella enterica serovar typhimurium to aminoglycosides in vitro and in vivo by a host-targeted antimicrobial agent.aminoglycosides exhibit relatively poor activity against intracellular salmonella enterica serovar typhimurium due to their low permeativity across eukaryotic cell membranes. previously, we identified the unique ability of ar-12, a celecoxib-derived small-molecule agent, to eradicate intracellular salmonella typhimurium in macrophages by facilitating autophagosome formation and suppressing akt kinase signaling. in light of this unique mode of antibacterial action, we investigated the ability of ...201425267669
salmonella enterica serovar enteritidis antimicrobial peptide resistance genes aid in defense against chicken innate immunity, fecal shedding, and egg deposition.salmonella enterica serovar enteritidis (s. enteritidis) is a major etiologic agent of nontyphoid salmonellosis in the united states. s. enteritidis persistently and silently colonizes the intestinal and reproductive tract of laying hens, resulting in contaminated poultry products. the consumption of contaminated poultry products has been identified as a significant risk factor for human salmonellosis. to understand the mechanisms s. enteritidis utilizes to colonize and persist in laying hens, w ...201425267840
molecular typing, antibiotic resistance, virulence gene and biofilm formation of different salmonella enterica serotypes.salmonella enterica isolates representing commonly isolated serotypes in tunisia were analyzed using genotyping and phenotyping methods. eric and its-pcr applied to 48 salmonella spp. isolates revealed the presence of 12 and 10 different profiles, respectively. the distribution of profiles among serotypes demonstrated the presence of strains showing an identical fingerprinting pattern. all salmonella strains used in this study were positive for the sdia gene. three salmonella isolates belonging ...201425273985
survival and fate of salmonella enterica serovar montevideo in adult horn flies (diptera: muscidae).contamination of cattle peripheral lymph nodes with salmonella enterica is proposed to occur via a transdermal route of entry. if so, bacteria may be introduced to cattle by biting arthropods. biting flies, such as horn flies (haematobia irritans irritans (l.)) (diptera: muscidae), are intriguing candidates for transmitting salmonella to cattle because they provide a route of entry when they breach the skin barrier during blood feeding. using a green fluorescent protein-expressing strain of salm ...201425276929
use of a live attenuated salmonella enterica serovar typhimurium vaccine on farrow-to-finish pig farms.salmonella enterica infection in pigs is economically important and poses a zoonotic risk. in this study, the efficacy of an attenuated s. enterica serovar typhimurium strain was evaluated in three farrow-to-finish pig herds. in each herd, 120 piglets were vaccinated orally at 3 and 24 days of age, while 120 piglets served as unvaccinated controls. faeces, ileocaecal lymph nodes and caecal contents were examined for s. typhimurium by isolation and serum was analysed for antibodies against s. typ ...201425278382
microbiological analysis of environmental samples collected from child care facilities in north and south carolina.children cared for outside the home are at an increased risk of enteric disease. microbiological analyses were performed on environmental samples collected from child care facilities in north and south carolina.201425278392
first complete genome sequence of salmonella enterica subsp. enterica serovar typhimurium strain atcc 13311 (nctc 74), a reference strain of multidrug resistance, as achieved by use of pacbio single-molecule real-time technology.we report the first complete genomic sequence of salmonella enterica subsp. enterica serovar typhimurium strain atcc 13311, the leading food-borne pathogen and a reference strain used in drug resistance studies. de novo assembly with pacbio sequencing completed its chromosome and one plasmid. they will accelerate the investigation into multidrug resistance in salmonella typhimurium.201425278532
microarray-based detection of salmonella enterica serovar enteritidis genes involved in chicken reproductive tract colonization.salmonella enterica serovar enteritidis has developed the potential to contaminate table eggs internally, by colonization of the chicken reproductive tract and internalization in the forming egg. the serotype enteritidis has developed mechanisms to colonize the chicken oviduct more successfully than other serotypes. until now, the strategies exploited by salmonella enteritidis to do so have remained largely unknown. for that reason, a microarray-based transposon library screen was used to identi ...201425281378
salmonella serovars and antimicrobial resistance in strains isolated from wild animals in captivity in sinaloa, mexico.the aim of the present study was to evaluate the frequency of antibiotic resistance in salmonella spp. strains from wild animals in captivity at the culiacan zoo and the mazatlan aquarium in sinaloa, mexico. we identified 17 different salmonella enterica serovars at a prevalence of 19.90% (culiacan zoo) and 6.25% (mazatlan aquarium). antibiotic sensitivity tests revealed that, of the 83 strains studied, 100% were multidrug resistant (mdr). the drugs against which the greatest resistance was obse ...201425282954
a comparison of the bax system method to the u.s. food and drug administration's bacteriological analytical manual and international organization for standardization reference methods for the detection of salmonella in a variety of soy ingredients.the performances of two dupont bax system pcr assays for detecting salmonella on a variety of low-moisture soy ingredients were evaluated against the u. s. food and drug administration's bacteriological analytical manual (fda bam) method or the international organization for standardization (iso) 6579 reference method. these evaluations were conducted as a single laboratory validation at an iso 17025 accredited third-party laboratory. validations were conducted on five soy ingredients: isolated ...201425285497
bacterial nucleoid-associated protein uncouples transcription levels from transcription timing.the histone-like nucleoid-structuring (h-ns) protein binds to horizontally acquired genes in the bacterium salmonella enterica serovar typhimurium, silencing their expression. we now report that overcoming the silencing effects of h-ns imposes a delay in the expression of genes activated by the transcriptional regulator phop. we determine that phop-activated genes ancestral to salmonella are expressed before those acquired horizontally. this expression timing reflects the in vivo occupancy of th ...201425293763
[study on the molecular epidemiology and antibiotic resistance of salmonella enterica serovar pomona].to study the epidemiological characteristics and antibiotic resistance of salmonella enterica serovar pomona (s. pomona).201425294079
development of a new molecular subtyping tool for salmonella enterica serovar enteritidis based on single nucleotide polymorphism genotyping using pcr.the lack of a sufficiently discriminatory molecular subtyping tool for salmonella enterica serovar enteritidis has hindered source attribution efforts and impeded regulatory actions required to disrupt its food-borne transmission. the underlying biological reason for the ineffectiveness of current molecular subtyping tools such as pulsed-field gel electrophoresis (pfge) and phage typing appears to be related to the high degree of clonality of s. enteritidis. by interrogating the organism's genom ...201425297333
study on the promotion of bacterial biofilm formation by a salmonella conjugative plasmid and the underlying mechanism.to investigate the effect of the prst98 plasmid, originally isolated from salmonella enterica serovar typhi (s. typhi), on biofilm (bf) formation, we carried out in vitro experiments using s. typhi, salmonella enterica serovar typhimurium (s. typhimurium) and escherichia coli (e. coli). we further explored the effects of prst98 in vivo by establishing two animal models, a tumor-bearing mouse model and a mouse urethral catheter model. moreover, we examined the relationship between the quorum-sens ...201425299072
antimicrobial activity of fermented theobroma cacao pod husk extract.theobroma cacao l. contains more than 500 different chemical compounds some of which have been traditionally used for their antioxidant, anti-carcinogenic, immunomodulatory, vasodilatory, analgesic, and antimicrobial activities. spontaneous aerobic fermentation of cacao husks yields a crude husk extract (che) with antimicrobial activity. che was fractioned by solvent partition with polar solvent extraction or by silica gel chromatography and a total of 12 sub-fractions were analyzed for chemical ...201425299086
complete genome sequence of salmonella enterica serovar choleraesuis vaccine strain c500 attenuated by chemical mutation.salmonella enterica serovar choleraesuis strain c500 is a live vaccine attenuated by chemical methods. here, we report the complete genome sequence of the strain, which may be helpful for elucidating the attenuation mechanism of the vaccine strain.201425301657
salmonella typhimurium strain atcc14028 requires h2-hydrogenases for growth in the gut, but not at systemic sites.salmonella enterica is a common cause of diarrhea. for eliciting disease, the pathogen has to colonize the gut lumen, a site colonized by the microbiota. this process/initial stage is incompletely understood. recent work established that one particular strain, salmonella enterica subspecies 1 serovar typhimurium strain sl1344, employs the hyb h2-hydrogenase for consuming microbiota-derived h2 to support gut luminal pathogen growth: protons from the h2-splitting reaction contribute to the proton ...201425303479
an ail family protein promotes type three secretion system-1-independent invasion and pathogenesis of salmonella enterica serovar typhi.adhesion and invasion of intestinal epithelial cells (iecs) are critical for the pathogenesis of salmonella typhi, the aetiological agent of human typhoid fever. while type three secretion system-1 (t3ss-1) is a major invasion apparatus of salmonella, independent invasion mechanisms were described for non-typhoidal salmonellae. here, we show that t2942, an ail-like protein of s. typhi ty2 strain, is required for adhesion and invasion of cultured iecs. that invasion was t3ss-1 independent was pro ...201525308535
trna modification enzymes gida and mnme: potential role in virulence of bacterial pathogens.transfer rna (trna) is an rna molecule that carries amino acids to the ribosomes for protein synthesis. these trnas function at the peptidyl (p) and aminoacyl (a) binding sites of the ribosome during translation, with each codon being recognized by a specific trna. due to this specificity, trna modification is essential for translational efficiency. many enzymes have been implicated in the modification of bacterial trnas, and these enzymes may complex with one another or interact individually wi ...201425310651
protective immunity against enteral stages of trichinella spiralis elicited in mice by live attenuated salmonella vaccine that secretes a 30-mer parasite epitope fused to the molecular adjuvant c3d-p28.the development of a veterinary vaccine against t. spiralis infection is an alternative strategy to control trichinellosis. in an effort to develop an efficient vaccine, balb/c mice were immunized with attenuated salmonella enterica serovar typhimurium sl3261 that expresses a 30-mer peptide (ag30) derived from the gp43 of t. spiralis muscle larvae fused to three copies of the molecular adjuvant p28 (ag30-p283) and it was either displayed on the surface or secreted by recombinant salmonella strai ...201425311159
detection of different serotypes of salmonella enterica in experimentally inoculated equine fecal samples by commercially available rapid tests.salmonella enterica can significantly impact management of animal facilities. comprehensive screening is essential for effective control in high-risk populations. availability of reliable point-of-care diagnostic tests would facilitate these efforts.201725312330
pathogenicity and phenotypic analysis of sopb, sopd and pipd virulence factors in salmonella enterica serovar typhimurium and salmonella enterica serovar agona.salmonella is an important food-borne pathogen causing disease in humans and animals worldwide. salmonellosis may be caused by any one of over 2,500 serovars of salmonella. nonetheless, salmonella enterica serovar typhimurium and salmonella enterica serovar agona are the second most prevalent serovars isolated from humans and livestock products respectively. limited knowledge is available about the virulence mechanisms responsible for diarrheal disease caused by them. to investigate the contribu ...201525312847
inhibition of salmonella enterica biofilm formation using small-molecule adenosine mimetics.biofilms have been widely implicated in chronic infections and environmental persistence of salmonella enterica, facilitating enhanced colonization of surfaces and increasing the ability of the bacteria to be transmitted to new hosts. salmonella enterica serovar typhi biofilm formation on gallstones from humans and mice enhances gallbladder colonization and bacterial shedding, while salmonella enterica serovar typhimurium biofilms facilitate long-term persistence in a number of environments impo ...201525313216
flgm is secreted by the flagellar export apparatus in bacillus subtilis.the bacterial flagellum is assembled from over 20 structural components, and flagellar gene regulation is morphogenetically coupled to the assembly state by control of the anti-sigma factor flgm. in the gram-negative bacterium salmonella enterica, flgm inhibits late-class flagellar gene expression until the hook-basal body structural intermediate is completed and flgm is inhibited by secretion from the cytoplasm. here we demonstrate that flgm is also secreted in the gram-positive bacterium bacil ...201525313396
lon-mediated proteolysis of the feoc protein prevents salmonella enterica from accumulating the fe(ii) transporter feob under high-oxygen conditions.the salmonella feo system consists of the feoa, feob, and feoc proteins and mediates ferrous iron [fe(ii)] import. feob is an inner membrane protein that, along with contributions from two small hydrophilic proteins, feoa and feoc, transports fe(ii). we previously reported that feoc binds to and protects the feob transporter from ftsh-mediated proteolysis. in the present study, we report proteolytic regulation of feoc that occurs in an oxygen-dependent fashion. while relatively stable under low- ...201525313398
antimicrobial profile of essential oils extracted from wild versus cultivated origanum ehrenberjii against enteric bacteria.the role of origanum ehrenberjii against bacteria that cause enteric diseases is well known. salmonella and enterococcus cause high rates of enteric infections around the world. the aim of this study was to extract essential oils from cultivated and naturally growing o. ehrenberjii, compare the chemical profiles of the extracts and estimate their antimicrobial efficacy against enteric pathogens.201425313614
osteomyelitis caused by salmonella enterica serovar derby in boa constrictor.after demonstrating chronic weight loss, prostration, and muscle flaccidness, a captive-bred 9-mo-old boa constrictor (boa constrictor constrictor) died and was submitted for necropsy. along the spinal column there were multiple, yellowish white, macroscopic nodules of 1-5 mm in diameter in the ventral side of the vertebral body and in the intervertebral spaces. severe multifocal necrotizing osteomyelitis associated with granulomatous inflammation was the main histologic finding in the vertebral ...201425314834
detection of zoonotic pathogens and characterization of novel viruses carried by commensal rattus norvegicus in new york city.norway rats (rattus norvegicus) are globally distributed and concentrate in urban environments, where they live and feed in closer proximity to human populations than most other mammals. despite the potential role of rats as reservoirs of zoonotic diseases, the microbial diversity present in urban rat populations remains unexplored. in this study, we used targeted molecular assays to detect known bacterial, viral, and protozoan human pathogens and unbiased high-throughput sequencing to identify ...201425316698
dna phosphorothioate modifications influence the global transcriptional response and protect dna from double-stranded breaks.the modification of dna by phosphorothioate (pt) occurs when the non-bridging oxygen in the sugar-phosphate backbone of dna is replaced with sulfur. this dna backbone modification was recently discovered and is governed by the dndabcde genes in a diverse group of bacteria and archaea. however, the biological function of dna pt modifications is poorly understood. in this study, we employed the rna-seq analysis to characterize the global transcriptional changes in response to pt modifications. our ...201425319634
acid exposure induces multiplication of salmonella enterica serovar typhi.salmonella enterica serovar typhi faces several environmental stresses while going through the stomach (acidic ph) to the small intestine (basic ph) and intracellularly in macrophages (acidic ph) in humans. the acidic ph followed by alkaline ph in the small intestine might be responsible for expression of certain stress-induced genes, resulting in not only better survival but also induction of multiplication and invasion of the bacterium in the small intestine. based on this hypothesis, we devel ...201425320227
pathogenic enterobacteria in lemurs associated with anthropogenic disturbance.as human population density continues to increase exponentially, speeding the reduction and fragmentation of primate habitat, greater human-primate contact is inevitable, making higher rates of pathogen transmission likely. anthropogenic effects are particularly evident in madagascar, where a diversity of endemic lemur species are threatened by rapid habitat loss. despite these risks, knowledge of how anthropogenic activities affect lemur exposure to pathogens is limited. to improve our understa ...201425328106
synthesis, characterization and antibacterial activity of biodegradable films prepared from schiff bases of zein.pure zein is known to be very hydrophobic, but is still inappropriate for coating and film applications because of their brittle nature. in an attempt to improve the flexibility and the antimicrobial activity of these coatings and films, chemical modification of zein through forming schiff bases with different phenolic aldhydes was tried. influence of this modifications on mechanical, topographical, wetting properties and antimicrobial activity of zein films were evaluated. the chemical structur ...201425328181
salmonella enterica serovar enteritidis and listeria monocytogenes in mango (mangifera indica l.) pulp: growth, survival and cross-contamination.this study examined the ability of salmonella enterica serovar enteritidis and listeria monocytogenes to grow or survive in mango pulp stored at -20°c, 4°c, 10°c and 25°c, as well as to cross-contaminate mangoes by means of a knife contaminated with different levels of these pathogens.201425328926
a bivalent typhoid live vector vaccine expressing both chromosome- and plasmid-encoded yersinia pestis antigens fully protects against murine lethal pulmonary plague infection.live attenuated bacteria hold great promise as multivalent mucosal vaccines against a variety of pathogens. a major challenge of this approach has been the successful delivery of sufficient amounts of vaccine antigens to adequately prime the immune system without overattenuating the live vaccine. here we used a live attenuated salmonella enterica serovar typhi strain to create a bivalent mucosal plague vaccine that produces both the protective f1 capsular antigen of yersinia pestis and the lcrv ...201525332120
an evaluation of alternative methods for constructing phylogenies from whole genome sequence data: a case study with salmonella.comparative genomics based on whole genome sequencing (wgs) is increasingly being applied to investigate questions within evolutionary and molecular biology, as well as questions concerning public health (e.g., pathogen outbreaks). given the impact that conclusions derived from such analyses may have, we have evaluated the robustness of clustering individuals based on wgs data to three key factors: (1) next-generation sequencing (ngs) platform (hiseq, miseq, iontorrent, 454, and solid), (2) algo ...201425332847
identification of antigenic proteins of the nosocomial pathogen klebsiella pneumoniae.the continuous expansion of nosocomial infections around the globe has become a precarious situation. key challenges include mounting dissemination of multiple resistances to antibiotics, the easy transmission and the growing mortality rates of hospital-acquired bacterial diseases. thus, new ways to rapidly detect these infections are vital. consequently, researchers around the globe pursue innovative approaches for point-of-care devices. in many cases the specific interaction of an antigen and ...201425333280
transcriptional specialization of human dendritic cell subsets in response to microbial vaccines.the mechanisms by which microbial vaccines interact with human apcs remain elusive. herein, we describe the transcriptional programs induced in human dcs by pathogens, innate receptor ligands and vaccines. exposure of dcs to influenza, salmonella enterica and staphylococcus aureus allows us to build a modular framework containing 204 transcript clusters. we use this framework to characterize the responses of human monocytes, monocyte-derived dcs and blood dc subsets to 13 vaccines. different vac ...201425335753
the mutagenicity analysis of imidapril hydrochloride and its degradant, diketopiperazine derivative, nitrosation mixtures by in vitro ames test with two strains of salmonella typhimurium.the evaluation of mutagenic properties of imidapril hydrochloride (imd) and its degradation impurity, diketopiperazine derivative (dkp), nitrosation mixtures was conducted in order to analyze the carcinogenic risk of imd long-term treatment in patients. in this study an in vitro ames test with salmonella enterica serovar typhimurium ta 98 and ta 100 strains was used.201425337415
characteristic and functional analysis of a newly established porcine small intestinal epithelial cell line.the mucosal surface of intestine is continuously exposed to both potential pathogens and beneficial commensal microorganisms. recent findings suggest that intestinal epithelial cells, which once considered as a simple physical barrier, are a crucial cell lineage necessary for maintaining intestinal immune homeostasis. therefore, establishing a stable and reliable intestinal epithelial cell line for future research on the mucosal immune system is necessary. in the present study, we established a ...201425337908
lyn deficiency leads to increased microbiota-dependent intestinal inflammation and susceptibility to enteric pathogens.the lyn tyrosine kinase governs the development and function of various immune cells, and its dysregulation has been linked to malignancy and autoimmunity. using models of chemically induced colitis and enteric infection, we show that lyn plays a critical role in regulating the intestinal microbiota and inflammatory responses as well as protection from enteric pathogens. lyn(-/-) mice were highly susceptible to dextran sulfate sodium (dss) colitis, characterized by significant wasting, rectal bl ...201425339668
salmonella-host interactions - modulation of the host innate immune system.salmonella enterica (s. enterica) are gram-negative bacteria that can invade a broad range of hosts causing both acute and chronic infections. this phenotype is related to its ability to replicate and persist within non-phagocytic host epithelial cells as well as phagocytic dendritic cells and macrophages of the innate immune system. infection with s. enterica manifests itself through a broad range of clinical symptoms and can result in asymptomatic carriage, gastroenteritis, systemic disease su ...201425339955
the master activator of inca/c conjugative plasmids stimulates genomic islands and multidrug resistance dissemination.dissemination of antibiotic resistance genes occurs mostly by conjugation, which mediates dna transfer between cells in direct contact. conjugative plasmids of the inca/c incompatibility group have become a substantial threat due to their broad host-range, the extended spectrum of antimicrobial resistance they confer, their prevalence in enteric bacteria and their very efficient spread by conjugation. however, their biology remains largely unexplored. using the inca/c conjugative plasmid pvcr94δ ...201425340549
recovery from an acute infection in c. elegans requires the gata transcription factor elt-2.the mechanisms involved in the recognition of microbial pathogens and activation of the immune system have been extensively studied. however, the mechanisms involved in the recovery phase of an infection are incompletely characterized at both the cellular and physiological levels. here, we establish a caenorhabditis elegans-salmonella enterica model of acute infection and antibiotic treatment for studying biological changes during the resolution phase of an infection. using whole genome expressi ...201425340560
esbl-producing salmonella enterica serovar typhi in traveler returning from guatemala to spain.we report a case of typhoid fever in a traveler returning to spain from guatemala that was caused by salmonella enterica serovar typhi which produced an extended-spectrum β-lactamase (esbl). this finding demonstrates the presence of esbl-producing s. enterica ser. typhi strains in the americas. enhanced surveillance is necessary to prevent further spread.201425340972
drug resistance in salmonella enterica ser. typhimurium bloodstream infection, malawi. 201425340988
evaluation of the live vaccine efficacy of virulence plasmid-cured, and phop- or aroa-deficient salmonella enterica serovar typhimurium in mice.we evaluated the protective efficacy of 94-kb virulence plasmid-cured, and phop- or aroa-deficient strains of salmonella enterica serovar typhimurium (δphop or δaroa s. typhimurium) as oral vaccine candidates in balb/c mice. two weeks after the completion of 3 oral immunizations with 1 × 10(8) colony-forming units (cfu) of virulence plasmid-cured, and δphop or δaroa s. typhimurium at 10-day intervals, s. typhimurium lipopolysaccharide (lps)-specific mucosal secretory immunoglobulin a (s-iga) ant ...201525341392
complete genome sequence of salmonella enterica subsp. enterica serovar enteritidis strain sej.salmonella enterica constitutes a group of enteric pathogens with a broad host range, including humans, reptiles, and birds. s. enterica subsp. enterica is a common cause of inflammatory diarrhea in humans. we present the draft genome of s. enterica subsp. enterica serovar enteritidis strain sej, including a 59-kbp plasmid.201425342692
convergent evolution in the assembly of polyubiquitin degradation signals by the shigella flexneri ipah9.8 ligase.the human pathogen shigella flexneri subverts host function and defenses by deploying a cohort of effector proteins via a type iii secretion system. the ipah family of 10 such effectors mimics ubiquitin ligases but bears no sequence or structural homology to their eukaryotic counterpoints. using rates of (125)i-polyubiquitin chain formation as a functional read out, ipah9.8 displays v-type positive cooperativity with respect to varying concentrations of its ubc5b∼(125)i-ubiquitin thioester co-su ...201425342744
comparative analysis of gene expression: uncovering expression conservation and divergence between salmonella enterica serovar typhimurium strains lt2 and 14028s.different strains of the same organism can share a large amount of their genetic material, the so called core pangenome. nevertheless, these species can display different lifestyles and it is still not well known to what extent the core pangenome plays a role in the divergence of lifestyles between the two organisms. here, we present a procedure for uncovering the conservation and divergence of gene expression by using large expression compendia. we will use data from two salmonella enterica ser ...201525343862
immune response of salmonella challenged broiler chickens fed diets containing gallipro®, a bacillus subtilis probiotic.this study was conducted to investigate the effect of feeding a probiotic, bacillus subtilis, on antibody titers against newcastle and infectious bursal viruses in broiler chickens challenged with salmonella enterica serotype enteritidis. one hundred and sixty 1-day-old broiler chicks were randomly assigned to four treatments in a completely randomized design. the treatments were negative control, probiotic-treated group, challenged group, and challenged probiotic treated group. salmonella chall ...201525344127
salmonella enterica in the chicken: how it has helped our understanding of immunology in a non-biomedical model species.salmonella infection of the chicken is important both as a source of foodborne human salmonellosis and as a source of disease in the chicken itself. vaccination and other control strategies require an understanding of the immune response and as such have been important in understanding both mucosal immunity and more generally the response to bacterial infection. in this review, we discuss the contribution the study of avian salmonellosis has made to understanding innate immunity including the fu ...201425346731
evolutionary expansion of a regulatory network by counter-silencing.horizontal gene transfer plays a major role in bacterial evolution. successful acquisition of new genes requires their incorporation into existing regulatory networks. this study compares the regulation of conserved genes in the phopq regulon of salmonella enterica serovar typhimurium with that of phopq-regulated horizontally acquired genes, which are silenced by the histone-like protein h-ns. we demonstrate that phop upregulates conserved and horizontally acquired genes by distinct mechanisms. ...201425348042
proteomes of host cell membranes modified by intracellular activities of salmonella enterica.intracellular pathogens need to establish a growth-stimulating host niche for survival and replication. a unique feature of the gastrointestinal pathogen salmonella enterica serovar typhimurium is the creation of extensive membrane networks within its host. an understanding of the origin and function of these membranes is crucial for the development of new treatment strategies. however, the characterization of this compartment is very challenging, and only fragmentary knowledge of its compositio ...201525348832
temporal and anatomical host resistance to chronic salmonella infection is quantitatively dictated by nramp1 and influenced by host genetic background.the lysosomal membrane transporter, nramp1, plays a key role in innate immunity and resistance to infection with intracellular pathogens such as non-typhoidal salmonella (nts). nts-susceptible c57bl/6 (b6) mice, which express the mutant nramp1d169 allele, are unable to control acute infection with salmonella enterica serovar typhimurium following intraperitoneal or oral inoculation. introducing functional nramp1g169 into the b6 host background, either by constructing a congenic strain carrying n ...201425350459
biofilm formation by enteric pathogens and its role in plant colonization and persistence.the significant increase in foodborne outbreaks caused by contaminated fresh produce, such as alfalfa sprouts, lettuce, melons, tomatoes and spinach, during the last 30 years stimulated investigation of the mechanisms of persistence of human pathogens on plants. emerging evidence suggests that salmonella enterica and escherichia coli, which cause the vast majority of fresh produce outbreaks, are able to adhere to and to form biofilms on plants leading to persistence and resistance to disinfectio ...201425351039
mutualistic interaction between salmonella enterica and aspergillus niger and its effects on zea mays colonization.salmonella typhimurium inhabits a variety of environments and is able to infect a broad range of hosts. throughout its life cycle, some hosts can act as intermediates in the path to the infection of others. aspergillus niger is a ubiquitous fungus that can often be found in soil or associated to plants and microbial consortia. recently, s. typhimurium was shown to establish biofilms on the hyphae of a. niger. in this work, we have found that this interaction is stable for weeks without a noticea ...201425351041
performance of etest and disk diffusion for detection of ciprofloxacin and levofloxacin resistance in salmonella enterica.we compared etest and disk diffusion to broth microdilution for the detection of fluoroquinolone resistance in 135 typhoidal and nontyphoidal serovars of salmonella. categorical agreements for the ciprofloxacin and levofloxacin etests were 89.6 and 83.7%, respectively. disk diffusion categorical agreements were 88.2 and 93.3%, respectively. only minor errors were observed.201525355768
multi-drug resistance and reduced susceptibility to ciprofloxacin among salmonella enterica serovar typhi isolates from the middle east and central asia.typhoid fever is common in developing countries, with an estimated 120 million infections and 700 000 annual deaths, worldwide. fluoroquinolones have been the treatment of choice for infection with multidrug-resistant (mdr) salmonella enterica serovar typhi (s. typhi). however, alarming reports of fluoroquinolone-resistance and failure of typhoid fever treatment have recently been published. to determine the proportion of s. typhi isolates with reduced susceptibility to ciprofloxacin (rsc) from ...201425356352
survival of salmonella enterica in aerated and nonaerated wastewaters from dairy lagoons.salmonella is the most commonly identified foodborne pathogen in produce, meat and poultry. cattle are known reservoirs of salmonella and the pathogen excreted in feces ends up in manure flush lagoons. salmonella enterica survival was monitored in wastewater from on-site holding lagoons equipped or not with circulating aerators at two dairies. all strains had poor survival rates and none proliferated in waters from aerated or settling lagoons. populations of all three salmonella serovars decline ...201425358096
first fully closed genome sequence of salmonella enterica subsp. enterica serovar cubana associated with a food-borne outbreak.salmonella enterica subsp. enterica serovar cubana (salmonella serovar cubana) is associated with human and animal disease. here, we used third-generation, single-molecule, real-time dna sequencing to determine the first complete genome sequence of salmonella serovar cubana cfsan002050, which was isolated from fresh alfalfa sprouts during a multistate outbreak in 2012.201425359917
antimicrobial susceptibility and molecular typing of salmonella agona isolated from humans and other sources.salmonella enterica serotype agona (salmonella agona) has been among the top 10 serotypes that cause human diarrheal diseases in china. a total of 95 salmonella agona (67 from humans, and 28 from animals, food of animal origins, and environmental sources) recovered in shanghai, china from 2005 to 2011 were subjected to antimicrobial susceptibility testing and molecular subtyping using pulsed-field gel electrophoresis (pfge). approximately 68.4% of the salmonella agona isolates were pansusceptibl ...201425361176
pathogenicity of salmonella strains isolated from egg shells and the layer farm environment in australia.in australia, the egg industry is periodically implicated during outbreaks of salmonella food poisoning. salmonella enterica serovar typhimurium and other nontyphoidal salmonella spp., in particular, are a major concern for australian public health. several definitive types of salmonella typhimurium strains, but primarily salmonella typhimurium definitive type 9 (dt9), have been frequently reported during egg-related food poisoning outbreaks in australia. the aim of the present study was to gene ...201525362057
rpos-regulated core genes involved in the competitive fitness of salmonella enterica serovar kentucky in the intestines of chickens.salmonella enterica serovar kentucky has become the most frequently isolated serovar from poultry in the united states over the past decade. despite its prevalence in poultry, it causes few human illnesses in the united states. the dominance of s. kentucky in poultry does not appear to be due to single introduction of a clonal strain, and its reduced virulence appears to correlate with the absence of virulence genes grva, ssei, sope, and sodc1. s. kentucky's prevalence in poultry is possibly att ...201525362062
loss of the lac operon contributes to salmonella invasion of epithelial cells through derepression of flagellar synthesis.salmonella, a genus that is closely related to escherichia coli, includes many pathogens of humans and other animals. a notable feature that distinguishes salmonella from e. coli is lactose negativity, because the lac operon is lost in most salmonella genomes. here, we expressed the lac operon in salmonella enterica serovar typhimurium and compared the virulence of the lac(+) strain to that of the wild-type strain in a murine model, invasion assays, and macrophage replication assays. we showed t ...201525362512
[determination of the antimicrobial capacity of green tea (camellia sinensis) against the potentially pathogenic microorganisms escherichia coli, salmonella enterica, staphylococcus aureus, listeria monocytogenes, candida albicans and aspergillus niger].many studies can be found in scientific literature demonstrating the antimicrobial capacity of different herbs, including green tea. never-theless, many results are divergent or cannot be compared. several green tea formulations may be found in market, but there is scarce or non-information about its activity. in this work, the potential antimicrobial effect of 50 samples of dry green tea and in 10% infusion against escherichia coli, salmonella enterica, listeria monocytogenes, staphylococcus au ...201325362825
synergistic effects of bifidobacterium thermophilum rbl67 and selected prebiotics on inhibition of salmonella colonization in the swine proximal colon polyferms model.probiotics and prebiotics are promising strategies to counteract salmonella prevalence in swine. in the present study, we investigated the effects of prebiotics (fructo- (fos), galacto- (gos) and mannan- (mos) oligosaccharides) and the bacteriocinogenic bifidobacterium thermophilum rbl67 (rbl67) on salmonella enterica subsp. enterica serovar typhimurium n-15 (n-15) colonization using the polyferms in vitro continuous fermentation model simulating the swine proximal colon.201425364390
transcriptional profiling of a cross-protective salmonella enterica serovar typhimurium uk-1 dam mutant identifies a set of genes more transcriptionally active compared to wild-type, and stably transcribed across biologically relevant microenvironments.vaccination with salmonella enterica serovar typhimurium lacking dna adenine methyltransferase confers cross-protective immunity against multiple salmonella serotypes. the mechanistic basis is thought to be associated with the de-repression of genes that are tightly regulated when transiting from one microenvironment to another. this de-repression provides a potential means for the production of a more highly expressed and stable antigenic repertoire capable of inducing cross-protective immune r ...201425364573
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