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corrected genome annotations reveal gene loss and antibiotic resistance as drivers in the fitness evolution of salmonella enterica serovar typhimurium.horizontal acquisition of novel chromosomal genes is considered to be a key process in the evolution of bacterial pathogens. however, the identification of gene presence or absence could be hindered by the inconsistencies in bacterial genome annotations. here, we performed a cross-annotation of omnipresent core and mosaic accessory genes in the chromosome of salmonella enterica serovar typhimurium across a total of 20 fully assembled genomes deposited into genbank. cross-annotation resulted in a ...201627621280
aroa-deficient salmonella enterica serovar typhimurium is more than a metabolically attenuated mutant.recombinant attenuated salmonella enterica serovar typhimurium strains are believed to act as powerful live vaccine carriers that are able to elicit protection against various pathogens. auxotrophic mutations, such as a deletion of aroa, are commonly introduced into such bacteria for attenuation without incapacitating immunostimulation. in this study, we describe the surprising finding that deletion of aroa dramatically increased the virulence of attenuated salmonella in mouse models. mutant bac ...201627601574
mapping the regulatory network for salmonella enterica serovar typhimurium invasion.salmonella enterica pathogenicity island 1 (spi-1) encodes proteins required for invasion of gut epithelial cells. the timing of invasion is tightly controlled by a complex regulatory network. the transcription factor (tf) hild is the master regulator of this process and senses environmental signals associated with invasion. hild activates transcription of genes within and outside spi-1, including six other tfs. thus, the transcriptional program associated with host cell invasion is controlled b ...201627601571
an orally administered dna vaccine targeting vascular endothelial growth factor receptor-3 inhibits lung carcinoma growth.lung cancer is the leading cause of mortality and 5-year survival rate is very low worldwide. recent studies show that vascular endothelial growth factor receptor-3 (vegfr-3) signaling pathway contributes to lung cancer progression. so we hypothesize that an oral dna vaccine that targets vegfr-3 carried by attenuated salmonella enterica serovar typhimurium strain sl3261 has impacts on lung cancer progression. in this study, the oral vegfr-3-based vaccine-immunized mice showed appreciable inhibit ...201626376999
laboratory-acquired infection with salmonella enterica serovar typhimurium exposed by whole-genome sequencing.despite advances in laboratory design, professional training, and workplace biosafety guidelines, laboratory-acquired infections continue to occur. effective tools are required to investigate cases and prevent future illness. here, we demonstrate the value of whole-genome sequencing as a tool for the identification and source attribution of laboratory-acquired salmonellosis.201626511736
genome sequence of bacteriophage gg32, which can infect both salmonella enterica serovar typhimurium and escherichia coli o157:h7.we report here a new virulent salmonella enterica serovar typhimurium (s typhimurium) bacteriophage, gg32, which was isolated from the guem river in the republic of korea. the strain can infect both s typhimurium and escherichia coli (e. coli) o157:h7 and may be a good candidate for a bio-control agent.201627932635
molecular profiling: catecholamine modulation of gene expression in escherichia coli o157:h7 and salmonella enterica serovar typhimurium.investigations of escherichia coli o157:h7 and salmonella enterica serovar typhimurium have demonstrated that these bacterial pathogens can respond to the presence of catecholamines including norepinephrine and/or epinephrine in their environment by modulating gene expression and exhibiting various phenotypes. for example, one of the most intensively investigated phenotypes following exposure of e. coli and s. typhimurium to norepinephrine is enhanced bacterial growth in a serum-based medium. ho ...201626589218
higher storage temperature causes greater salmonella enterica serovar typhimurium internal penetration of artificially contaminated, commercially available, washed free range eggs.foodborne salmonellosis is a major public health concern, with contaminated eggs identified as a significant source of infection. in australia, the most prevalent cause of salmonellosis from eggs is salmonella enterica subsp. enterica serovar typhimurium. this study explored the effect of temperature after 1, 7, 14, 21, and 28 days of storage on commercially available washed free range eggs, artificially contaminated with salmonella typhimurium on the external surface. at each time point, the ex ...201627357046
antimicrobial resistance and class 1 integron-associated gene cassettes in salmonella enterica serovar typhimurium isolated from pigs at slaughter and abattoir environment.forty-five multi-resistant salmonella enterica subsp. enterica serovar (s.) typhimurium isolates obtained at five pig abattoirs in southern brazil were characterized. their relatedness was determined by xbai-macrorestriction analysis. resistance genes, integrons and plasmid-mediated quinolone resistance genes (pmqr) were investigated by pcr. amplicons for the variable part of class 1 integrons and the quinolone resistance-determining regions (qrdr) were sequenced. plasmids were characterized by ...201627142182
complete genome sequence of salmonella enterica serovar typhimurium strain so2 (sequence type 302) isolated from an asymptomatic child in mexico.the complete genome sequence ofsalmonella entericaserovar typhimurium strain so2, isolated from an asymptomatic child in mexico, was determined using pacbio single-molecule real-time technology. strain so2 has six complete chromosomal prophages, namely, st104, gifsy-2, st64b, gifsy-1, elphis, and fsl sp-004, and carries asalmonellavirulence plasmid.201627081133
cobalamin production by lactobacillus coryniformis: biochemical identification of the synthetized corrinoid and genomic analysis of the biosynthetic cluster.despite the fact that most vitamins are present in a variety of foods, malnutrition, unbalanced diets or insufficient intake of foods are still the cause of vitamin deficiencies in humans in some countries. vitamin b12 (cobalamin) is a complex compound that is only naturally produced by bacteria and archea. it has been reported that certain strains belonging to lactic acid bacteria group are capable of synthesized water-soluble vitamins such as those included in the b-group, as vitamin b12. in t ...201627737643
live attenuated human salmonella vaccine candidates: tracking the pathogen in natural infection and stimulation of host immunity.salmonellosis, caused by members of the genus salmonella, is responsible for considerable global morbidity and mortality in both animals and humans. in this review, we will discuss the pathogenesis of salmonella enterica serovar typhi and salmonella enterica serovar typhimurium, focusing on human salmonella infections. we will trace the path of salmonella through the body, including host entry sites, tissues and organs affected, and mechanisms involved in both pathogenesis and stimulation of hos ...201627809955
lose to win: mart pseudogenization in salmonella enterica serovar typhi contributed to the surv-dependent survival to h2o2, and inside human macrophage-like cells.the difference in host range between salmonella enterica serovar typhimurium (s. typhimurium) and salmonella enterica serovar typhi (s. typhi) can be partially attributed to the gain of functions, to the loss of functions (i.e. pseudogenization), or to a combination of both processes. as previously reported, the loss of functions by pseudogenization may play a role in bacterial evolution, especially in host-restricted pathogens such as s. typhi. the mart-fidl operon, located at the spi-3, encode ...201627567490
salmonella extracellular matrix components influence biofilm formation and gallbladder colonization.salmonella enterica serovar typhi, the causative agent of typhoid fever in humans, forms biofilms encapsulated by an extracellular matrix (ecm). biofilms facilitate colonization and persistent infection in gallbladders of humans and mouse models of chronic carriage. individual roles of matrix components have not been completely elucidated in vitro or in vivo to examine individual functions, strains of salmonella enterica serovar typhimurium, the murine model of s typhi, in which various ecm gene ...201627600501
loss of multicellular behavior in epidemic african nontyphoidal salmonella enterica serovar typhimurium st313 strain d23580.nontyphoidal salmonella enterica serovar typhimurium is a frequent cause of bloodstream infections in children and hiv-infected adults in sub-saharan africa. most isolates from african patients with bacteremia belong to a single sequence type, st313, which is genetically distinct from gastroenteritis-associated st19 strains, such as 14028s and sl1344. some studies suggest that the rapid spread of st313 across sub-saharan africa has been facilitated by anthroponotic (person-to-person) transmissio ...201626933058
exploiting a host-commensal interaction to promote intestinal barrier function and enteric pathogen tolerance.commensal intestinal bacteria can prevent pathogenic infection; however, limited knowledge of the mechanisms by which individual bacterial species contribute to pathogen resistance has restricted their potential for therapeutic application. here, we examined how colonization of mice with a human commensal enterococcus faecium protects against enteric infections. we show that e. faecium improves host intestinal epithelial defense programs to limit salmonella enterica serotype typhimurium pathogen ...201628580440
intermediate filaments enable pathogen docking to trigger type 3 effector translocation.type 3 secretion systems (t3sss) of bacterial pathogens translocate bacterial effector proteins that mediate disease into the eukaryotic cytosol. effectors traverse the plasma membrane through a translocon pore formed by t3ss proteins. in a genome-wide selection, we identified the intermediate filament vimentin as required for infection by the t3ss-dependent pathogen s. flexneri. we found that vimentin is required for efficient t3ss translocation of effectors by s. flexneri and other pathogens t ...201627572444
complete, closed genome sequences of 10 salmonella enterica subsp. enterica serovar typhimurium strains isolated from human and bovine sources.salmonella enterica is a leading cause of enterocolitis for humans and animals. s. enterica subsp. enterica serovar typhimurium infects a broad range of hosts. to facilitate genomic comparisons among isolates from different sources, we present the complete genome sequences of 10 s typhimurium strains, 5 each isolated from human and bovine sources.201627811097
genomic analysis of salmonella enterica serovar typhimurium from wild passerines in england and wales.passerine salmonellosis is a well-recognized disease of birds in the order passeriformes, which includes common songbirds such as finches and sparrows, caused by infection with salmonella enterica serovar typhimurium. previous research has suggested that some subtypes of s typhimurium-definitive phage types (dts) 40, 56 variant, and 160-are host adapted to passerines and that these birds may represent a reservoir of infection for humans and other animals. here, we have used the whole-genome sequ ...201627613688
novel approach of a phage-based magnetoelastic biosensor for the detection of salmonella enterica serovar typhimurium in soil.to date, there has been no employment of a magnetoelastic (me) biosensor method to detect salmonella enterica serovar typhimurium in soil. the me biosensor method needs to be investigated and modified for its successful performance. the filtration method, cation-exchange resin method, and combinations of both methods were employed for the extraction of s. typhimurium from soil. the number of s. typhimurium and the resonant frequency shift of the me sensor were then compared using a brilliant gre ...201627728960
a case study on salmonella enterica serovar typhimurium at a dairy farm associated with massive sparrow death.salmonella enterica typhimurium (s. typhimurium) is the most common cause of bovine salmonellosis in japan and where it is also cause of salmonellosis in wild birds. in 2008, a postpartum cow at a dairy farm developed diarrhea caused by s. typhimurium. the herd was extensively surveilled for salmonella sp. and we characterized bacterial isolates from this and other cows to determine the source of infection.201627112780
wild-type and mutant avra- salmonella induce broadly similar immune pathways in the chicken ceca with key differences in signaling intermediates and inflammation.salmonella enterica serovar typhimurium (st) is a serious infectious disease throughout the world, and a major reservoir for salmonella is chicken. chicken infected with salmonella do not develop clinical disease, this may be the result of important host interactions with key virulence proteins. to study this, we inoculated chicken with mutant salmonella typhimurium that lacked the virulence protein avra (avra(-)). avra is referred to as an avirulence factor, as it moderates the host immune resp ...201626574031
the effect of recombinant human lactoferrin from the milk of transgenic cows on salmonella enterica serovar typhimurium infection in mice.lactoferrin (lf) is a multifunctional protein with antibacterial and immunomodulatory activities. given this beneficial effect, transgenic approaches have been used to produce lactoferrin. the aim of the current study was to investigate the in vivo effect of recombinant human lactoferrin (rhlf) from the milk of transgenic cows on salmonella enterica serovar typhimurium (st) infection in mice. two hours before the infection with 0.3 ml at 2 × 10(5) cfu ml(-1) of st, each animal in the st + rhlf g ...201626469086
the architecture of the cytoplasmic region of type iii secretion systems.type iii secretion systems (t3sss) are essential devices in the virulence of many gram-negative bacterial pathogens. they mediate injection of protein effectors of virulence from bacteria into eukaryotic host cells to manipulate them during infection. t3sss involved in virulence (vt3sss) are evolutionarily related to bacterial flagellar protein export apparatuses (ft3sss), which are essential for flagellar assembly and cell motility. the structure of the external and transmembrane parts of both ...201627686865
breast abscess due to salmonella typhimurium in a patient with rheumatoid arthritis: a case report.this is the first report of breast abscess due to salmonella enterica serotype typhimurium. staphylococcus aureus is known as the most common cause of breast abscess. salmonella spp. may occasionally form localized abscesses after dissemination to various organ systems following a bacteraemia. but breast abscess related to salmonella spp is a very rare complication.201627448659
ex vivo perfusion of the isolated rat small intestine as a novel model of salmonella enteritis.using an ex vivo perfused rat small intestinal model, we examined pathological changes to the tissue, inflammation induction, as well as dynamic changes to smooth muscle activity, metabolic competence, and luminal fluid accumulation during short-term infection with the enteropathogenic bacteria salmonella enterica serovar typhimurium and yersinia enterocolitica. although few effects were seen upon yersinia infection, this system accurately modeled key aspects associated with salmonella enteritis ...201626564721
complete genome sequence of a myoviridae bacteriophage infecting salmonella enterica serovar typhimurium.the bacteriophage 118970_sal3 was isolated from water buffalo feces in southern italy, exhibiting lytic activity against salmonella enterica serovar typhimurium. this bacteriophage belongs to the myoviridae family and has a 39,464-bp double-stranded dna (ds-dna) genome containing 53 coding sequences (cdss).201627688333
curcumin reduces the motility of salmonella enterica serovar typhimurium by binding to the flagella, thereby leading to flagellar fragility and shedding.one of the important virulence properties of the pathogen is its ability to travel to a favorable environment, cross the viscous mucus barrier (intestinal barrier for enteric pathogens), and reach the epithelia to initiate pathogenesis with the help of an appendage, like flagella. nonetheless, flagella can act as an "achilles heel," revealing the pathogen's presence to the host through the stimulation of innate and adaptive immune responses. we assessed whether curcumin, a dietary polyphenol, co ...201627091154
prevalence, seasonal occurrence, and antimicrobial resistance of salmonella spp. isolates recovered from chicken carcasses sampled at major poultry processing plants of south korea.the current study was conducted to assess salmonella spp. contamination in chicken carcasses produced at major poultry processing plants in south korea. in total, 120 chicken carcasses were collected through 12 individual trials (10 chickens per trial) from six poultry processing plants in the summer of 2014 and the winter of 2015. eighteen chicken samples (15%) were contaminated with salmonella, with a higher rate of contamination observed during summer (14 isolates, 11.7%) than during winter ( ...201627442349
application of antimicrobial agents via commercial spray cabinet to inactivate salmonella on skinless chicken meat.salmonella enterica subsp. enterica serovar typhimurium is a food safety concern for raw poultry products. new and innovative application methods of antimicrobials for the reduction of salmonella in poultry and poultry products are essential. the aim of this study was to determine the efficacy of three antimicrobial compounds against salmonella on raw chicken meat when applied individually and in combination using a commercial spray cabinet. raw chicken thigh meat inoculated with 5 log cfu/g sal ...201627052860
characterization of virulence-associated genes, antimicrobial resistance genes, and class 1 integrons in salmonella enterica serovar typhimurium isolates from chicken meat and humans in egypt.foodborne pathogens are leading causes of illness especially in developing countries. the current study aimed to characterize virulence-associated genes and antimicrobial resistance in 30 salmonella typhimurium isolates of chicken and human origin at mansoura, egypt. the results showed that inva, avra, mgtc, stn, and bcfc genes were identified in all the examined isolates, while 96.7% and 6.7% were positive for sopb and pef genes, respectively. the highest resistance frequencies of the isolates ...201626977940
novel two-step hierarchical screening of mutant pools reveals mutants under selection in chicks.contaminated chicken/egg products are major sources of human salmonellosis, yet the strategies used by salmonella to colonize chickens are poorly understood. we applied a novel two-step hierarchical procedure to identify new genes important for colonization and persistence of salmonella enterica serotype typhimurium in chickens. a library of 182 s. typhimurium mutants each containing a targeted deletion of a group of contiguous genes (for a total of 2,069 genes deleted) was used to identify regi ...201626857572
mucosal immunization of balb/c mice with dna vaccines encoding the sen1002 and sen1395 open reading frames of salmonella enterica serovar enteritidis induces protective immunity.salmonella enteritidis is the main cause of foodborne salmonellosis worldwide. the limited effectiveness of current interventions against this pathogen has been the main incentive to develop new methods for the efficient control of this infection. to investigate the use of dna vaccines against s. enteritidis in humans, immune responses stimulated by two plasmids containing the genes designated sen1002, located in the pathogenicity island spi-19 and encoding a hcp protein involved in transport me ...201626113459
physiological fluid shear alters the virulence potential of invasive multidrug-resistant non-typhoidal salmonella typhimurium d23580.salmonella enterica serovar typhimurium strains belonging to sequence type st313 are a major cause of fatal bacteremia among hiv-infected adults and children in sub-saharan africa. unlike "classical" non-typhoidal salmonella (nts), gastroenteritis is often absent during st313 infections and isolates are most commonly recovered from blood, rather than from stool. this is consistent with observations in animals, in which st313 strains displayed lower levels of intestinal colonization and higher re ...201628725732
towards an understanding of salmonella enterica serovar typhimurium persistence in swine.salmonella enterica is an important food borne pathogen that is frequently carried by swine. carrier animals pose a food safety risk because they can transmit s. enterica to finished food products in the processing plant or by contamination of the environment. environmental contamination has become increasingly important as non-animal foods (plant-based) have been implicated as sources of s. enterica. the prevalence of s. enterica in swine is high and yet carrier animals remain healthy. s. enter ...201628155802
evolution of variable number tandem repeats and its relationship with genomic diversity in salmonella typhimurium.salmonella enterica serovar typhimurium is the most common salmonella serovar causing human infections in australia and many other countries. a total of 12,112 s. typhimurium isolates from new south wales were analyzed by multi-locus variable number of tandem repeat (vntr) analysis (mlva) using five vntrs from 2007 to 2014. we found that mid ranges of repeat units of 8-14 in vntr locus sttr5, 6-13 in sttr6, and 9-12 in sttr10 were always predominant in the population (>50%). in vitro passaging e ...201628082952
an unusual case of septic arthritis of the hip.non-typhoidal salmonella, particularly salmonella enterica serovar typhimurium is food borne pathogen causing mild self-limiting diarrhoea in healthy adults. it can occasionally cause extraintestinal focal infection in susceptible patients. salmonella, as the aetiological agent of osteomyelitis and septic arthritis is rare and has been mostly reported in patients with sickle cell disease or thalassaemia. we report a case of septic arthritis by salmonellatyphimurium in an immunocompromised patien ...201628050370
peroxiredoxin-3 is involved in bactericidal activity through the regulation of mitochondrial reactive oxygen species.peroxiredoxin-3 (prdx3) is a mitochondrial protein of the thioredoxin family of antioxidant peroxidases and is the principal peroxidase responsible for metabolizing mitochondrial hydrogen peroxide. recent reports have shown that mitochondrial reactive oxygen species (mros) contribute to macrophage-mediated bactericidal activity in response to toll-like receptors. herein, we investigated the functional effect of prdx3 in bactericidal activity. the mitochondrial localization of prdx3 in hek293t ce ...201628035213
near-atomic-resolution cryo-em analysis of the salmonella t3s injectisome basal body.the type iii secretion (t3s) injectisome is a specialized protein nanomachine that is critical for the pathogenicity of many gram-negative bacteria, including purveyors of plague, typhoid fever, whooping cough, sexually transmitted infections and major nosocomial infections. this syringe-shaped 3.5-mda macromolecular assembly spans both bacterial membranes and that of the infected host cell. the internal channel formed by the injectisome allows for the direct delivery of partially unfolded virul ...201627974800
the infectious intracellular lifestyle of salmonella enterica relies on the adaptation to nutritional conditions within the salmonella-containing vacuole.salmonella enterica serovar typhimurium (s. typhimurium) is a gram-negative pathogen that causes various host-specific diseases. during their life cycle, salmonellae survive frequent exposures to a variety of environmental stresses, e.g. carbon-source starvation. the virulence of this pathogen relies on its ability to establish a replicative niche, named salmonella-containing vacuole, inside host cells. however, the microenvironment of the scv and the bacterial metabolic pathways required during ...201627936347
protective immunity elicited by oral immunization of mice with salmonella enterica serovar typhimurium braun lipoprotein (lpp) and acetyltransferase (msbb) mutants.we evaluated the extent of attenuation and immunogenicity of the δlppab and δlppab δmsbb mutants of salmonella enterica serovar typhimurium when delivered to mice by the oral route. these mutants were deleted either for the braun lipoprotein genes (lppa and lppb) or in combination with the msbb gene, which encodes an acetyltransferase required for lipid a modification of lipopolysaccharide. both the mutants were attenuated (100% animal survival) and triggered robust innate and adaptive immune re ...201627891321
studies on the therapeutic effect of propolis along with standard antibacterial drug in salmonella enterica serovar typhimurium infected balb/c mice.antibiotic resistance is an emerging public health problem. centers for disease control and prevention (cdc) has described antibiotic resistance as one of the world's most pressing health problems in 21(st) century. who rated antibiotic resistance as "one of the three greatest threats to human health". one important strategy employed to overcome this resistance is the use of combination of drugs. many plants, natural extracts have been shown to exhibit synergistic response with standard drugs ag ...201627887651
genome-guided design of a defined mouse microbiota that confers colonization resistance against salmonella enterica serovar typhimurium.protection against enteric infections, also termed colonization resistance, results from mutualistic interactions of the host and its indigenous microbes. the gut microbiota of humans and mice is highly diverse and it is therefore challenging to assign specific properties to its individual members. here, we have used a collection of murine bacterial strains and a modular design approach to create a minimal bacterial community that, once established in germ-free mice, provided colonization resist ...201627869789
mg2+ regulates transcription of mgta in salmonella typhimurium via translation of proline codons during synthesis of the mgtl peptide.in salmonella enterica serovar typhimurium, mg(2+) limitation induces transcription of the mgta mg(2+) transport gene, but the mechanism involved is unclear. the 5' leader of the mgta mrna contains a 17-codon, proline-rich orf, mgtl, whose translation regulates the transcription of mgta [park s-y et al. (2010) cell 142:737-748]. rapid translation of mgtl promotes formation of a secondary structure in the mgta mrna that permits termination of transcription by the rho protein upstream of mgta, whe ...201627849575
single-cell rna-seq ties macrophage polarization to growth rate of intracellular salmonella.intracellular bacterial pathogens can exhibit large heterogeneity in growth rate inside host cells, with major consequences for the infection outcome. if and how the host responds to this heterogeneity remains poorly understood. here, we combined a fluorescent reporter of bacterial cell division with single-cell rna-sequencing analysis to study the macrophage response to different intracellular states of the model pathogen salmonella enterica serovar typhimurium. the transcriptomes of individual ...201627841856
effect of holarrhena antidysentrica (ha) and andrographis paniculata (ap) on the biofilm formation and cell membrane integrity of opportunistic pathogen salmonella typhimurium.increasing occurrence of gastroenteritis outbreaks caused by food borne opportunistic microorganisms has become a major problem in food industry as well as in immunocompromised host. antimicrobial agents are losing their efficacy due to increase in the microbial resistance. for such reasons, conventional treatment has become limited to manage the infections state. need of the hour is to instigate the search for safer holistic alternatives. the present study was hence conducted to assess the anti ...201627836761
a proteomic approach to the development of diva elisa distinguishing pigs infected with salmonella typhimurium and pigs vaccinated with a salmonella typhimurium-based inactivated vaccine.salmonella enterica serovar typhimurium is one of the most common enteropathogenic bacteria found in pigs in europe. in our previous work, we demonstrated the protective effects in suckling piglets when their dams had been vaccinated with an s. typhimurium-based inactivated vaccine. this study is focused on a procedure leading to serological discrimination between vaccinated and infected pigs. as we supposed, distinct environment during natural infection and in bacterial cultures used for vaccin ...201627835998
pgadb-builder: a web service tool for creating pan-genome allele database for molecular fine typing.with the advance of next generation sequencing techniques, whole genome sequencing (wgs) is expected to become the optimal method for molecular subtyping of bacterial isolates. to use wgs as a general subtyping method for disease outbreak investigation and surveillance, the layout of wgs-based typing must be comparable among laboratories. whole genome multilocus sequence typing (wgmlst) is an approach that achieves this requirement. to apply wgmlst as a standard subtyping approach, a pan-genome ...201627824078
a salmonella nanoparticle mimic overcomes multidrug resistance in tumours.salmonella enterica serotype typhimurium is a food-borne pathogen that also selectively grows in tumours and functionally decreases p-glycoprotein (p-gp), a multidrug resistance transporter. here we report that the salmonella type iii secretion effector, sipa, is responsible for p-gp modulation through a pathway involving caspase-3. mimicking the ability of salmonella to reverse multidrug resistance, we constructed a gold nanoparticle system packaged with a sipa corona, and found this bacterial ...201627452236
nutrient deprivation affects salmonella invasion and its interaction with the gastrointestinal microbiota.salmonella enterica serovar typhimurium (s. typhimurium) is a foodborne enteric pathogen and a major cause of gastroenteritis in humans. it is known that molecules derived from the human fecal microbiota downregulate s. typhimurium virulence gene expression and induce a starvation-like response. in this study, s. typhimurium was cultured in minimal media to mimic starvation conditions such as that experienced by s. typhimurium in the human intestinal tract, and the pathogen's virulence in vitro ...201627437699
energy taxis toward host-derived nitrate supports a salmonella pathogenicity island 1-independent mechanism of invasion.salmonella enterica serovar typhimurium can cross the epithelial barrier using either the invasion-associated type iii secretion system (t3ss-1) or a t3ss-1-independent mechanism that remains poorly characterized. here we show that flagellum-mediated motility supported a t3ss-1-independent pathway for entering ileal peyer's patches in the mouse model. flagellum-dependent invasion of peyer's patches required energy taxis toward nitrate, which was mediated by the methyl-accepting chemotaxis protei ...201627435462
gold nanoparticle-dna aptamer conjugate-assisted delivery of antimicrobial peptide effectively eliminates intracellular salmonella enterica serovar typhimurium.antimicrobial peptides (amps) are a promising new class of antibacterial compounds. however, their applications in the treatment of intracellular pathogenic bacteria have been limited by their in vivo instability and low penetrating ability into mammalian cells. here, we report that gold nanoparticles conjugated with dna aptamer (aunp-apt) efficiently delivered amps into mammalian living systems with enhanced stability of the amps. c-terminally hexahistidine-tagged a3-apo (a3-apo(his)) amps were ...201627424215
regulated delayed synthesis of lipopolysaccharide and enterobacterial common antigen of salmonella typhimurium enhances immunogenicity and cross-protective efficacy against heterologous salmonella challenge.lipopolysaccharide (lps) o-antigen and enterobacterial common antigen (eca) are two major polysaccharide structures on the surface of salmonella enterica serovar typhimurium. previous studies have demonstrated that regulated truncation of lps enhances the cross-reaction against conserved outer membrane proteins (omps) from enteric bacteria. we speculate that the regulation of both o-antigen and eca may enhance the induction of immune responses against conserved omps from enteric bacteria. in thi ...201627423383
models of intestinal infection by salmonella enterica: introduction of a new neonate mouse model.salmonella enterica serovar typhimurium is a foodborne pathogen causing inflammatory disease in the intestine following diarrhea and is responsible for thousands of deaths worldwide. many in vitro investigations using cell culture models are available, but these do not represent the real natural environment present in the intestine of infected hosts. several in vivo animal models have been used to study the host-pathogen interaction and to unravel the immune responses and cellular processes occu ...201627408697
lps remodeling triggers formation of outer membrane vesicles in salmonella.outer membrane vesicles (omv) are proposed to mediate multiple functions during pathogenesis and symbiosis. however, the mechanisms responsible for omv formation remain poorly understood. it has been shown in eukaryotic membranes that lipids with an inverted-cone shape favor the formation of positive membrane curvatures. based on these studies, we formulated the hypothesis that lipid a deacylation might impose shape modifications that result in the curvature of the outer membrane (om) and subseq ...201627406567
mice deficient in angiopoietin-like protein 2 (angptl2) gene show increased susceptibility to bacterial infection due to attenuated macrophage activity.macrophages play crucial roles in combatting infectious disease by promoting inflammation and phagocytosis. angiopoietin-like protein 2 (angptl2) is a secreted factor that induces tissue inflammation by attracting and activating macrophages to produce inflammatory cytokines in chronic inflammation-associated diseases such as obesity-associated metabolic syndrome, atherosclerosis, and rheumatoid arthritis. here, we asked whether and how angptl2 activates macrophages in the innate immune response. ...201627402837
licoflavonol is an inhibitor of the type three secretion system of salmonella enterica serovar typhimurium.as an important food-borne human pathogen, salmonella enterica serovar typhimurium depends on its type iii secretion system (t3ss) as a major virulence factor to cause disease all over the world. the t3ss secretes effector proteins to facilitate invasion into host cells. in this study, twenty prenylated flavonoids (1-20) were screened for their anti-t3ss activity, revealing that several analogs exhibited strong inhibitory effects on the secretion of salmonella pathogenicity island 1 (spi-1)-asso ...201627387231
beneficial effects of sodium phenylbutyrate administration during infection with salmonella enterica serovar typhimurium.sodium phenylbutyrate (pba) is a derivative of the short-chain fatty acid butyrate and is approved for treatment of urea cycle disorders and progressive familial intrahepatic cholestasis type 2. previously known functions include histone deacetylase inhibitor, endoplasmic reticulum stress inhibitor, ammonia sink, and chemical chaperone. here, we show that pba has a previously undiscovered protective role in host mucosal defense during infection. administration of pba to taconic mice resulted in ...201627382022
igg subclasses targeting the flagella of salmonella enterica serovar typhimurium can mediate phagocytosis and bacterial killing.invasive non-typhoidal salmonella are a common cause of invasive disease in immuno-compromised individuals and in children. multi-drug resistance poses challenges to disease control, with a critical need for effective vaccines. flagellin is an attractive vaccine candidate due to surface exposure and high epitope copy number, but its potential as a target for opsonophacytic antibodies is unclear. we examined the effect of targeting flagella with different classes of igg on the interaction between ...201627366588
transfer of salmonella enterica serovar typhimurium from beef to tomato through kitchen equipment and the efficacy of intermediate decontamination procedures.it is well established that a high percentage of foodborne illness is caused by failure of consumers to prepare food in a hygienic manner. indeed, a common practice in households is to use the same kitchen equipment for both raw meat and fresh produce. such a practice may lead to cross-contamination of fruits and vegetables, which are mainly consumed without further processing, with pathogenic microorganisms originating from raw meat. the present study was performed to examine the transfer of th ...201627357047
trna(pro) -mediated downregulation of elongation factor p is required for mgtcbr expression during salmonella infection.bacterial ribosome requires elongation factor p to translate fragments harbouring consecutive proline codons. given the abundance of orfs with potential ef-p regulated sites, ef-p was assumed to be constitutively expressed. here, we report that the intracellular pathogen salmonella enterica serovar typhimurium decreases efp mrna levels during course of infection. we determined that the decrease in efp mrna is triggered by low levels of charged trna(pro) , a condition that salmonella experiences ...201627350030
hydrosol of thymbra capitata is a highly efficient biocide against salmonella enterica serovar typhimurium biofilms.salmonella is recognized as one of the most significant enteric foodborne bacterial pathogens. in recent years, the resistance of pathogens to biocides and other environmental stresses, especially when they are embedded in biofilm structures, has led to the search for and development of novel antimicrobial strategies capable of displaying both high efficiency and safety. in this direction, the aims of the present work were to evaluate the antimicrobial activity of hydrosol of the mediterranean s ...201627342550
salmonella mitigates oxidative stress and thrives in the inflamed gut by evading calprotectin-mediated manganese sequestration.neutrophils hinder bacterial growth by a variety of antimicrobial mechanisms, including the production of reactive oxygen species and the secretion of proteins that sequester nutrients essential to microbes. a major player in this process is calprotectin, a host protein that exerts antimicrobial activity by chelating zinc and manganese. here we show that the intestinal pathogen salmonella enterica serovar typhimurium uses specialized metal transporters to evade calprotectin sequestration of mang ...201627281571
phenotypic and genetic changes in the life cycle of small colony variants of salmonella enterica serotype typhimurium induced by streptomycin.small colony variants (scvs), constituting a slow-growing subpopulation of bacteria that facilitates persistence in lethal environmental conditions, are able to revert to the phenotype of rapid growth for further proliferation and transmission. salmonella enterica serotype typhimurium is one of the most important foodborne pathogens. this study investigated the genetic mechanisms how scvs induced by streptomycin reverted to the fast-growing phenotype and the phenotypic changes of scvs among thei ...201627245674
poor biofilm-forming ability and long-term survival of invasive salmonella typhimurium st313.salmonella enterica serovar typhimurium, an enteric pathogen that causes a self-limiting gastroenteritis, forms biofilms on different surfaces. in sub-saharan africa, salmonella typhimurium of a novel sequence type (st) 313 was identified and produces septicemia in the absence of gastroenteritis. no animal reservoir has been identified, and it is hypothesized that transmission occurs via human to human. in this study, we show that invasive salmonella typhimurium st313 strains from mali are poor ...201627222487
comparison of methods for quantitating salmonella enterica typhimurium and heidelberg strain attachment to reusable plastic shipping container coupons and preliminary assessment of sanitizer efficacy.salmonella serovars, one of the leading contributors to foodborne illness and are especially problematic for foods that are not cooked before consumption, such as fresh produce. the shipping containers that are used to transport and store fresh produce may play a role in cross contamination and subsequent illnesses. however, methods for quantitatively attached cells are somewhat variable. the overall goal of this study was to compare conventional plating with molecular methods for quantitating a ...201627192211
strains, mechanism, and perspective: salmonella-based cancer therapy.recently, investigation of bacterial-based tumor therapy has regained focus due to progress in molecular, cellular, and microbial biology. many bacteria such as salmonella, listeria, escherichia, and clostridium have proved to have tumor targeting and in some cases even tumor-destroying phenotypes. furthermore, bacterial clinical treatments for cancer have been improved by combination with other therapeutic methods such as chemotherapeutic drugs and radioactive agents. synthetic biology techniqu ...201627190519
pediatric epidemic of salmonella enterica serovar typhimurium in the area of l'aquila, italy, four years after a catastrophic earthquake.a salmonella enterica epidemic occurred in children of the area of l'aquila (central italy, abruzzo region) between june 2013 and october 2014, four years after the catastrophic earthquake of 6 april 2009.201627164121
rapid dna transformation in salmonella typhimurium by the hydrogel exposure method.even with advances in molecular cloning and dna transformation, new or alternative methods that permit dna penetration in salmonella enterica subspecies enterica serovar typhimurium are required in order to use this pathogen in biotechnological or medical applications. in this work, an adapted protocol of bacterial transformation with plasmid dna based on the "yoshida effect" was applied and optimized on salmonella enterica serovar typhimurium lt2 reference strain. the plasmid transference based ...201627154729
bacteriophages with potential to inactivate salmonella typhimurium: use of single phage suspensions and phage cocktails.the aim of this study was to compare the dynamics of three previously isolated bacteriophages (or phages) individually (phse-1, phse-2 and phse-5) or combined in cocktails of two or three phages (phse-1/phse-2, phse-1/phse-5, phse-2/phse-5 and phse-1/phse-2/phse-5) to control salmonella enterica serovar typhimurium (salmonella typhimurium) in order to evaluate their potential application during depuration. phages were assigned to the family siphoviridae and revealed identical restriction digest ...201627126773
outbreak of unusual salmonella enterica serovar typhimurium monophasic variant 1,4 [5],12:i:-, italy, june 2013 to september 2014.monophasic variant of salmonella enterica subspecies enterica serovar typhimurium (monophasic s. typhimurium), with antigenic structure 1,4,[5],12:i:-, appears to be of increasing importance in europe. in italy, monophasic s. typhimurium represented the third most frequent salmonella serovar isolated from human cases between 2004 and 2008. from june 2013 to october 2014, a total of 206 human cases of salmonellosis were identified in abruzzo region (central italy). obtained clinical isolates char ...201627105170
assessing the effect of sodium dichloroisocyanurate concentration on transfer of salmonella enterica serotype typhimurium in wash water for production of minimally processed iceberg lettuce (lactuca sativa l.).this study evaluated the impact of sodium dichloroisocyanurate (5, 10, 20, 30, 40, 50 and 250 mg l(-1) ) in wash water on transfer of salmonella typhimurium from contaminated lettuce to wash water and then to other noncontaminated lettuces washed sequentially in the same water. experiments were designed mimicking the conditions commonly seen in minimally processed vegetable (mpv) processing plants in brazil. the scenarios were as follows: (1) washing one inoculated lettuce portion in nonchlorina ...201627105015
complete genome sequence of salmonella enterica serovar typhimurium strain so3 (sequence type 302) isolated from a baby with meningitis in mexico.the complete genome of italic! salmonella entericaserovar typhimurium strain so3 (sequence type 302), isolated from a fatal meningitis infection in mexico, was determined using pacbio technology. the chromosome hosts six complete prophages and is predicted to harbor 51 genomic islands, including 13 pathogenicity islands (spis). it carries the italic! salmonellavirulence plasmid (pstv).201627103717
complete genome sequence of salmonella enterica serovar typhimurium strain yu15 (sequence type 19) harboring the salmonella genomic island 1 and virulence plasmid pstv.the complete genome ofsalmonella entericasubsp.entericaserovar typhimurium sequence type 19 (st19) strain yu15, isolated in yucatán, mexico, from a human baby stool culture, was determined using pacbio technology. the chromosome contains five intact prophages and thesalmonellagenomic island 1 (sgi1). this strain carries thesalmonellavirulence plasmid pstv.201627081132
depletion of butyrate-producing clostridia from the gut microbiota drives an aerobic luminal expansion of salmonella.the mammalian intestine is host to a microbial community that prevents pathogen expansion through unknown mechanisms, while antibiotic treatment can increase susceptibility to enteric pathogens. here we show that streptomycin treatment depleted commensal, butyrate-producing clostridia from the mouse intestinal lumen, leading to decreased butyrate levels, increased epithelial oxygenation, and aerobic expansion of salmonella enterica serovar typhimurium. epithelial hypoxia and salmonella restricti ...201627078066
selection and characterization of aptamers using a modified whole cell bacterium selex for the detection of salmonella enterica serovar typhimurium.this study describes the selection of single-stranded dna (ssdna) aptamers against salmonella enterica serovar typhimurium using a modified whole cell systematic evolution of ligands by exponential enrichment (whole cell selex). for evolving specific aptamers, ten rounds of selection to live salmonella cells, alternating with negative selection against a cocktail of related pathogens, were performed. the resulting highly enriched oligonucleotide pools were sequenced and clustered into eight grou ...201627070414
ctx-m-27 producing salmonella enterica serotypes typhimurium and indiana are prevalent among food-producing animals in china.salmonella spp. is one of the most important food-borne pathogens causing digestive tract and invasive infections in both humans and animals. extended-spectrum β-lactamases (esbls) especially the ctx-m-type esbls are increasingly being reported worldwide and in china. these studies seldom focused on salmonella isolates from food-producing animals. the aim of this study was to characterize the antimicrobial resistance profiles, serotypes and esbls and in particular, ctx-m producing salmonella iso ...201627065989
impacts of salmonella enterica serovar typhimurium and its speg gene on the transcriptomes of in vitro m cells and caco-2 cells.microfold or membranous (m) cells are specialized intestinal epithelial cells responsible for host immunity. the speg mutant of salmonella typhimurium (s. typhimurium) is a nonreplicating strain within human cells to be a candidate vaccine vector for interacting with m cells. we conducted this study to identify the genes are differently expressed between in vitro m cells and caco-2 cells, and to determine whether s. typhimurium and speg affect the transcriptomes of both cell types. in vitro m ce ...201627064787
multiple roles of putrescine and spermidine in stress resistance and virulence of salmonella enterica serovar typhimurium.polyamines (putrescine and spermidine) are small-cationic amines ubiquitous in nature and present in most living cells. in recent years they have been linked to virulence of several human pathogens including shigella spp and salmonella enterica serovar typhimurium (s. typhimurium). central to s. typhimurium virulence is the ability to survive and replicate inside macrophages and resisting the antimicrobial attacks in the form of oxidative and nitrosative stress elicited from these cells. in the ...201627041598
salmonella typhimurium infection primes a nutriprive mechanism in piglets.salmonella enterica serovar typhimurium (s. typhimurium) is an important cause of acute food- borne zoonoses worldwide, typically carried by pigs. it is well known that salmonella has evolved a wide array of strategies enabling it to invade the host, but little information is available on the specific host responses to salmonella infections. in the present study, we used an in vivo approach (involving piglets infected with a virulent or an attenuated s. typhimurium strain) coupled to histologica ...201627016766
immunogenicity and cross-protective efficacy induced by outer membrane proteins from salmonella typhimurium mutants with truncated lps in mice.lipopolysaccharide (lps) is a major virulence factor present in the outer membrane of salmonella enterica serovar typhimurium (s. typhimurium). outer membrane proteins (omps) from salmonella show high immunogenicity and provide protection against salmonella infection, and truncated lps alters the outer membrane composition of the cell wall. in our previous study, we demonstrated that salmonella mutants carrying truncated lps failed to induce strong immune responses and cross-reaction to other en ...201627011167
antioxidant defense by thioredoxin can occur independently of canonical thiol-disulfide oxidoreductase enzymatic activity.the thiol-disulfide oxidoreductase cxxc catalytic domain of thioredoxin contributes to antioxidant defense in phylogenetically diverse organisms. we find that although the oxidoreductase activity of thioredoxin-1 protects salmonella enterica serovar typhimurium from hydrogen peroxide in vitro, it does not appear to contribute to salmonella's antioxidant defenses in vivo. nonetheless, thioredoxin-1 defends salmonella from oxidative stress resulting from nadph phagocyte oxidase macrophage expressi ...201626997275
increased efficacy of inactivated vaccine candidates prepared with salmonella enterica serovar typhimurium strains of predominant genotypes in ducks.salmonella enterica serovar typhimurium has been a major causative agent of food-borne human disease, mainly due to consumption of contaminated food animal products. in particular, ducks serve as a reservoir of serovar typhimurium, and are one of the common sources of human infection. to prevent infection of ducks, and therefore minimize human infection, it is critical to control the persistent epidemic strains in ducks. here, we analyzed the genetic diversity and virulence of serovar typhimuriu ...201626994209
specific monoclonal antibody overcomes the salmonella enterica serovar typhimurium's adaptive mechanisms of intramacrophage survival and replication.salmonella-specific antibodies play an important role in host immunity; however, the mechanisms of salmonella clearance by pathogen-specific antibodies remain to be completely elucidated since previous studies on antibody-mediated protection have yielded inconsistent results. these inconsistencies are at least partially attributable to the use of polyclonal antibodies against salmonella antigens. here, we developed a new monoclonal antibody (mab)-449 and identified its related immunogen that pro ...201626986057
proteomic insight into the effects of the salmonella ubiquitin ligase slrp on host cells.the virulence of the human and animal pathogen salmonella enterica serovar typhimurium is dependent on two type iii secretion systems. these systems translocate proteins called effectors into eukaryotic host cells. slrp is a salmonella type iii secretion effector with ubiquitin ligase activity. here, we used two complementary proteomic approaches, two-dimensional gel electrophoresis and itraq (isobaric tags for relative and absolute quantification) to study the consequences of the presence of sl ...201626966069
global genomic epidemiology of salmonella enterica serovar typhimurium dt104.it has been 30 years since the initial emergence and subsequent rapid global spread of multidrug-resistant salmonella entericaserovar typhimurium dt104 (mdr dt104). nonetheless, its origin and transmission route have never been revealed. we used whole-genome sequencing (wgs) and temporally structured sequence analysis within a bayesian framework to reconstruct temporal and spatial phylogenetic trees and estimate the rates of mutation and divergence times of 315s typhimurium dt104 isolates sample ...201626944846
characterization of salmonella enterica serovar typhimurium isolates from pigs and pig environment-related sources and evidence of new circulating monophasic strains in spain.a total of 117 salmonella enterica serovar typhimurium and 59 monophasic salmonella typhimurium (s. enterica serovar 4,[5],12:i:-) strains isolated between 2008 and 2012 from pig, wild bird, rodent, and farm environment samples from the northeast of spain were characterized by phage typing, antibiotic susceptibility testing, and multiple-locus variable-number tandem repeat analysis in order to evaluate their phenotypic and genetic relatedness. in salmonella 4,[5],12:i:-, the most prevalent phage ...201626939650
optimizing salmonella enterica serovar typhimurium for bacteria-mediated tumor therapy.bacteria-mediated tumor therapy using salmonella enterica serovar typhimurium is a therapeutic option with great potential. numerous studies explored the potential of salmonella typhimurium for therapeutic applications, however reconciling safety with vectorial efficacy remains a major issue. recently we have described a conditionally attenuated salmonella vector that is based on genetic lipopolysaccharide modification. this vector combines strong attenuation with appropriate anti-tumor properti ...201626939530
detection of a novel gyrb mutation associated with fluoroquinolone-nonsusceptible salmonella enterica serovar typhimurium isolated from a bloodstream infection in ghana.a multidrug-resistant salmonella enterica serovar typhimurium with reduced susceptibility to ciprofloxacin was isolated from the blood of a hospitalized child in ghana. dna sequencing identified a novel gyrb mutation at codon 466 (glu466asp). an increase in fluoroquinolone susceptibility after the introduction of a wild-type gyrb(+) allele demonstrated that the gyrb466 mutation had a direct effect on fluoroquinolone susceptibility.201626933021
determination of the stoichiometry of the complete bacterial type iii secretion needle complex using a combined quantitative proteomic approach.precisely knowing the stoichiometry of their components is critical for investigating structure, assembly, and function of macromolecular machines. this has remained a technical challenge in particular for large, hydrophobic membrane-spanning protein complexes. here, we determined the stoichiometry of a type iii secretion system of salmonella enterica serovar typhimurium using two complementary protocols of gentle complex purification combined with peptide concatenated standard and synthetic sta ...201626900162
intestinal long-chain fatty acids act as a direct signal to modulate expression of the salmonella pathogenicity island 1 type iii secretion system.salmonella enterica serovar typhimurium uses the salmonella pathogenicity island 1 (spi1) type iii secretion system (t3ss) to induce inflammatory diarrhea and bacterial uptake into intestinal epithelial cells. the expression of hila, encoding the transcriptional activator of the t3ss structural genes, is directly controlled by three arac-like regulators, hild, hilc, and rtsa, each of which can activate hild, hilc, rtsa, and hila genes, forming a complex feed-forward regulatory loop. expression o ...201626884427
real-time optotracing of curli and cellulose in live salmonella biofilms using luminescent oligothiophenes.extracellular matrix (ecm) is the protein- and polysaccharide-rich backbone of bacterial biofilms that provides a defensive barrier in clinical, environmental and industrial settings. understanding the dynamics of biofilm formation in native environments has been hindered by a lack of research tools. here we report a method for simultaneous, real-time, in situ detection and differentiation of the salmonella ecm components curli and cellulose, using non-toxic, luminescent conjugated oligothiophen ...201628721253
modulation of the substitution pattern of 5-aryl-2-aminoimidazoles allows fine-tuning of their antibiofilm activity spectrum and toxicity.we previously synthesized several series of compounds, based on the 5-aryl-2-aminoimidazole scaffold, that showed activity preventing the formation of salmonella enterica serovar typhimurium and pseudomonas aeruginosa biofilms. here, we further studied the activity spectrum of a number of the most active n1- and 2n-substituted 5-aryl-2-aminoimidazoles against a broad panel of biofilms formed by monospecies and mixed species of bacteria and fungi. an n1-substituted compound showed very strong act ...201627550355
exploring the diversity and antimicrobial potential of marine actinobacteria from the comau fjord in northern patagonia, chile.bioprospecting natural products in marine bacteria from fjord environments are attractive due to their unique geographical features. although, actinobacteria are well known for producing a myriad of bioactive compounds, investigations regarding fjord-derived marine actinobacteria are scarce. in this study, the diversity and biotechnological potential of actinobacteria isolated from marine sediments within the comau fjord, in northern chilean patagonia, were assessed by culture-based approaches. ...201627486455
salmonella suppresses the trif-dependent type i interferon response in macrophages.salmonella enterica is an intracellular pathogen that causes diseases ranging from gastroenteritis to typhoid fever. salmonella bacteria trigger an autophagic response in host cells upon infection but have evolved mechanisms for suppressing this response, thereby enhancing intracellular survival. we recently reported that s. enterica serovar typhimurium actively recruits the host tyrosine kinase focal adhesion kinase (fak) to the surface of the salmonella-containing vacuole (scv) (k. a. owen et ...201626884434
identification of essential genes in the salmonella phage spn3us reveals novel insights into giant phage head structure and assembly.giant tailed bacterial viruses, or phages, such as pseudomonas aeruginosa phage ϕkz, have long genomes packaged into large, atypical virions. many aspects of ϕkz and related phage biology are poorly understood, mostly due to the fact that the functions of the majority of their proteins are unknown. we hypothesized that the salmonella enterica phage spn3us could be a useful model phage to address this gap in knowledge. the 240-kb spn3us genome shares a core set of 91 genes with ϕkz and related ph ...201627605673
the in vitro redundant enzymes purn and purt are both essential for systemic infection of mice in salmonella enterica serovar typhimurium.metabolic enzymes show a high degree of redundancy, and for that reason they are generally ignored in searches for novel targets for anti-infective substances. the enzymes purn and purt are redundant in vitro in salmonella enterica serovar typhimurium, in which they perform the third step of purine synthesis. surprisingly, the results of the current study demonstrated that single-gene deletions of each of the genes encoding these enzymes caused attenuation (competitive infection indexes [ci] of ...201627113361
trogocytosis-associated cell to cell spread of intracellular bacterial pathogens.macrophages are myeloid-derived phagocytic cells and one of the first immune cell types to respond to microbial infections. however, a number of bacterial pathogens are resistant to the antimicrobial activities of macrophages and can grow within these cells. macrophages have other immune surveillance roles including the acquisition of cytosolic components from multiple types of cells. we hypothesized that intracellular pathogens that can replicate within macrophages could also exploit cytosolic ...201626802627
persistence and potential viable but non-culturable state of pathogenic bacteria during storage of digestates from agricultural biogas plants.despite the development of on-farm anaerobic digestion as a process for making profitable use of animal by-products, factors leading to the inactivation of pathogenic bacteria during storage of digestates remain poorly described. here, a microcosm approach was used to evaluate the persistence of three pathogenic bacteria (salmonella enterica derby, campylobacter coli and listeria monocytogenes) in digestates from farms, stored for later land spreading. nine samples, including raw digestates, liq ...201627695451
subtyping of salmonella enterica subspecies i using single-nucleotide polymorphisms in adenylate cyclase.methods to rapidly identify serotypes of salmonella enterica subspecies i are of vital importance for protecting the safety of food. to supplement the serotyping method dkgb-linked intergenic sequence ribotyping (isr), single-nucleotide polymorphisms were characterized within adenylate cyclase (cyaa). the national center for biotechnology information (ncbi) database had 378 cyaa sequences from s. enterica subspecies i, which included 42 unique dna sequences and 19 different amino acid sequences. ...201627035032
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