| hypochlorous acid and hydrogen peroxide-induced negative regulation of salmonella enterica serovar typhimurium ompw by the response regulator arca. | hydrogen peroxide (h2o2) and hypochlorous acid (hocl) are reactive oxygen species that are part of the oxidative burst encountered by salmonella enterica serovar typhimurium (s. typhimurium) upon internalization by phagocytic cells. in order to survive, bacteria must sense these signals and modulate gene expression. growing evidence indicates that the arcab two component system plays a role in the resistance to reactive oxygen species. we investigated the influx of h2o2 and hocl through ompw and ... | 2012 | 22545862 |
| evidence for lack of acquisition of tolerance in salmonella enterica serovar typhimurium atcc 14028 after exposure to subinhibitory amounts of origanum vulgare l. essential oil and carvacrol. | overnight exposure of salmonella enterica serovar typhimurium to sublethal amounts of origanum vulgare essential oil (ov) and carvacrol (car) did not result in direct and cross-bacterial protection. cells subcultured with increasing amounts of ov or car survived up to the mic of either compound, revealing few significant changes in bacterial susceptibility. | 2012 | 22544235 |
| the transcriptional landscape and small rnas of salmonella enterica serovar typhimurium. | more than 50 y of research have provided great insight into the physiology, metabolism, and molecular biology of salmonella enterica serovar typhimurium (s. typhimurium), but important gaps in our knowledge remain. it is clear that a precise choreography of gene expression is required for salmonella infection, but basic genetic information such as the global locations of transcription start sites (tsss) has been lacking. we combined three rna-sequencing techniques and two sequencing platforms to ... | 2012 | 22538806 |
| quantifying ligand binding to large protein complexes using electrospray ionization mass spectrometry. | an electrospray ionization mass spectrometry (esi-ms) method for quantifying protein-ligand complexes that cannot be directly detected by esi-ms is described. the proxy protein esi-ms method combines direct esi-ms binding measurements with competitive protein-ligand binding. to implement the method, a proxy protein (p(proxy)), which interacts specifically with the ligand of interest with known affinity and can be detected directly by esi-ms, is used to quantitatively monitor the extent of ligand ... | 2012 | 22507285 |
| three-axis model for atg recruitment in autophagy against salmonella. | salmonella enterica serovar typhimurium enter epithelial cells and take up residence there. within epithelial cells, a portion of the bacteria are surrounded by an autophagosome-like double-membrane structure, and they are still residing within the salmonella-containing vacuole (scv). in this paper, we will discuss how the autophagy machinery is recruited in proximity to salmonella. the formation of this double membrane requires atg9l1 and fip200; these proteins are important for autophagy-speci ... | 2012 | 22505927 |
| analysis of hilc/d-dependent invf promoter expression under different culture conditions. | in salmonella enterica serovar typhimurium, many of the genes required for intestinal penetration and invasion of host cells are encoded within the salmonella pathogenicity island 1 (spi1). the expression of invf, which is a positive transcriptional activator of spi1, is controlled by hila-dependent (invf-1) and hilc/d-dependent (invf-2) promoters. transcriptional analysis of invf revealed that the invf-2 promoter (p(invf-2)) was not activated when cells were grown in standing culture conditions ... | 2012 | 22480973 |
| association of a protective monoclonal iga with the o antigen of salmonella enterica serovar typhimurium impacts type 3 secretion and outer membrane integrity. | invasion of intestinal epithelial cells by salmonella enterica serovar typhimurium is an energetically demanding process, involving the transfer of effector proteins from invading bacteria into host cells via a specialized organelle known as the salmonella pathogenicity island 1 (spi-1) type 3 secretion system (t3ss). by a mechanism that remains poorly understood, entry of s. typhimurium into epithelial cells is inhibited by sal4, a monoclonal, polymeric iga antibody that binds an immunodominant ... | 2012 | 22473607 |
| improving resolution of public health surveillance for human salmonella enterica serovar typhimurium infection: 3 years of prospective multiple-locus variable-number tandem-repeat analysis (mlva). | prospective typing of salmonella enterica serovar typhimurium (stm) by multiple-locus variable-number tandem-repeat analysis (mlva) can assist in identifying clusters of stm cases that might otherwise have gone unrecognised, as well as sources of sporadic and outbreak cases. this paper describes the dynamics of human stm infection in a prospective study of stm mlva typing for public health surveillance. | 2012 | 22462487 |
| presence and persistence of salmonella enterica serotype typhimurium in the phyllosphere and rhizosphere of spray-irrigated parsley. | salmonella enterica is one of the major food-borne pathogens associated with ready-to-eat fresh foods. although polluted water might be a significant source of contamination in the field, factors that influence the transfer of salmonella from water to the crops are not well understood, especially under conditions of low pathogen levels in water. the aim of this study was to investigate the short- and long-term (1 h to 28 days) persistence of salmonella enterica serotype typhimurium in the phyllo ... | 2012 | 22447598 |
| enhancement of the anti-salmonella immune response in cd154-deficient mice by an attenuated, ifn-γ-expressing, strain of salmonella enterica serovar typhimurium. | previously, we demonstrated that cell-cell communications via the cd40-cd154 pathway play a critical role in the induction of type 1 cytokine responses, including il-12 and ifn-γ, which in turn greatly influence the response to salmonella infections. mice genetically deficient in the expression of cd154 exhibited markedly increased susceptibility to infection by an attenuated, double auxotrophic (aroa-arod-) strain, designated brd509, of salmonella enterica serovar typhimurium. in the present st ... | 2012 | 22445817 |
| oral and intranasal administration of somatostatin dna vaccine mediated by attenuated salmonella enterica serovar typhimurium to promote growth of piglets. | an attenuated strain of salmonella typhimurium has been used as a carrier for oral and intranasal genetic immunization. here, we evaluate the efficacy of a vaccine strain of s. typhimurium. cso22 (pgm-csf/ss, plasmid granulocyte-macrophage colony-stimulating factor/somatostatin) expressing two copies of ss genes. a total of 115 piglets, aged 2 months old, were either orally or intranasally immunized against the vaccine strain cso22 (pgm-csf/ss) with three dosages (5 × 10(10) colony forming units ... | 2011 | 22440175 |
| the late endosomal adaptor p14 is a macrophage host-defense factor against salmonella infection. | the outcome of an infection depends on the balance between host resistance and bacterial virulence. here, we show that the late endosomal adaptor p14 (also known as lamtor2) is one of the components for cellular host defense against the intracellular pathogen salmonella enterica serovar typhimurium. during salmonella infection, the complex of p14 and mp1 is required for the accurately timed transport of salmonella through the endolysosomal system. loss of p14 opens a time window that allows salm ... | 2012 | 22427693 |
| evasion of human innate immunity without antagonizing tlr4 by mutant salmonella enterica serovar typhimurium having penta-acylated lipid a. | modification of a lipid a moiety in gram-negative bacterial lps to a less acylated form is thought to facilitate bacterial evasion of host innate immunity, thereby enhancing pathogenicity. the contribution of less-acylated lipid a to interactions of whole bacterial cells with host cells (especially in humans) remains unclear. mutant strains of salmonella enterica serovar typhimurium with fewer acylated groups were generated. the major lipid a form in wild-type (wt) and the mutant kcs237 strain i ... | 2012 | 22419537 |
| characterization of dals, an atp-binding cassette transporter for d-alanine, and its role in pathogenesis in salmonella enterica. | expansion into new host niches requires bacterial pathogens to adapt to changes in nutrient availability and to evade an arsenal of host defenses. horizontal acquisition of salmonella pathogenicity island (spi)-2 permitted the expansion of salmonella enterica serovar typhimurium into the intracellular environment of host cells by allowing it to deliver bacterial effector proteins across the phagosome membrane. this is facilitated by the ssra-ssrb two-component regulatory system and a type iii se ... | 2012 | 22418438 |
| strand length-dependent antimicrobial activity and membrane-active mechanism of arginine- and valine-rich β-hairpin-like antimicrobial peptides. | antimicrobial peptides with amphipathic β-hairpin-like structures have potent antimicrobial properties and low cytotoxicity. the effect of vr or rv motifs on β-hairpin-like antimicrobial peptides has not been investigated. in this study, a series of β-hairpin-like peptides, ac-c(vr)(n)(d)pg (rv)(n)c-nh(2) (n = 1, 2, 3, 4, or 5), were synthesized, and the effect of chain length on antimicrobial activity was evaluated. the antimicrobial activity of the peptides initially increased and then decreas ... | 2012 | 22391533 |
| differential outcome of infection with attenuated salmonella in myd88-deficient mice is dependent on the route of administration. | activation of the innate immune system is a prerequisite for the induction of adaptive immunity to both infectious and non-infectious agents. tlrs are key components of the innate immune recognition system and detect pathogen-associated molecular patterns. most tlrs utilize the myd88 adaptor for their signaling pathways. in the current study, we investigated innate and adaptive immune responses to primary as well as secondary salmonella infections in myd88-deficient (myd88(-/-)) mice. using i.p. ... | 2013 | 22386951 |
| genome scanning for conditionally essential genes in salmonella enterica serotype typhimurium. | as more whole-genome sequences become available, there is an increasing demand for high-throughput methods that link genes to phenotypes, facilitating discovery of new gene functions. in this study, we describe a new version of the tn-seq method involving a modified ez:tn5 transposon for genome-wide and quantitative mapping of all insertions in a complex mutant library utilizing massively parallel illumina sequencing. this tn-seq method was applied to a genome-saturating salmonella enterica sero ... | 2012 | 22367088 |
| a third mode of surface-associated growth: immobilization of salmonella enterica serovar typhimurium modulates the rpos-directed transcriptional programme. | although the growth of bacteria has been studied for more than a century, it is only in recent decades that surface-associated growth has received attention. in addition to the well-characterized biofilm and swarming lifestyles, bacteria can also develop as micro-colonies supported by structured environments in both food products and the gi tract. this immobilized mode of growth has not been widely studied. to develop our understanding of the effects of immobilization upon a food-borne bacterial ... | 2012 | 22356617 |
| laboratory-based surveillance of non-typhoidal salmonella infections in guangdong province, china. | salmonella is one of the most common foodborne pathogens in humans. laboratory-based surveillance for non-typhoidal salmonella infection was conducted in guangdong province, china to improve understanding about the disease burden and detection of dispersed outbreaks. salmonella isolated from patients with diarrhea were sent from 16 sentinel hospitals to local public health laboratories for confirmation, serotyping, antimicrobial susceptibility testing, and pulsed-field gel electrophoresis (pfge) ... | 2012 | 22356574 |
| peroral ciprofloxacin therapy impairs the generation of a protective immune response in a mouse model for salmonella enterica serovar typhimurium diarrhea, while parenteral ceftriaxone therapy does not. | nontyphoidal salmonella (nts) species cause self-limiting diarrhea and sometimes severe disease. antibiotic treatment is considered only in severe cases and immune-compromised patients. the beneficial effects of antibiotic therapy and the consequences for adaptive immune responses are not well understood. we used a mouse model for salmonella diarrhea to assess the effects of per os treatment with ciprofloxacin (15 mg/kg of body weight intragastrically 2 times/day, 5 days) or parenteral ceftriaxo ... | 2012 | 22354292 |
| igg keeps virulent salmonella from evading dendritic cell uptake. | dendritic cells (dcs) are phagocytic professional antigen-presenting cells that can prime naive t cells and initiate anti-bacterial immunity. however, several pathogenic bacteria have developed virulence mechanisms to impair dc function. for instance, salmonella enterica serovar typhimurium can prevent dcs from activating antigen-specific t cells. in addition, it has been described that the salmonella pathogenicity island 1 (spi-1), which promotes phagocytosis of bacteria in non-phagocytic cells ... | 2012 | 22352313 |
| hfq and hfq-dependent small rnas are major contributors to multicellular development in salmonella enterica serovar typhimurium. | the rna chaperone hfq and its associated small rnas (srnas) regulate a variety of phenotypes in bacteria. in this work, we show that hfq is a master regulator of biofilm formation in salmonella enterica serovar typhimurium. hfq and two hfq-dependent srnas (arcz and sdsr) are required for rdar morphotype expression in s. typhimurium. hfq controls rdar biofilm formation through the major biofilm regulator csgd. while csgd mrna steady-state levels are altered in a sdsr mutant, arcz seems to work ma ... | 2012 | 22336758 |
| development of carbapenem resistance during therapy for non-typhoid salmonella infection. | multidrug-resistant salmonella infection is a global problem, and carbapenems may represent the last therapeutic choice. we report a case of infection caused by ceftriaxone-resistant and ciprofloxacin-resistant salmonella enterica serotype typhimurium. a bla(cmy-2) -containing tn6092, located on a self-transferable inci1 plasmid, was found in all isolates derived from the patient. during ertapenem treatment, the strain developed carbapenem resistance. apart from the ompd deficiency found in all ... | 2012 | 22329543 |
| dksa-dependent resistance of salmonella enterica serovar typhimurium against the antimicrobial activity of inducible nitric oxide synthase. | in coordination with the ppgpp alarmone, the rna polymerase regulatory protein dksa controls the stringent response of eubacteria, negatively regulating transcription of translational machinery and directly activating amino acid promoters and de novo amino acid biosynthesis. given the effects of nitric oxide (no) on amino acid biosynthetic pathways and the intimate relationship of dksa with amino acid synthesis and transport, we tested whether dksa contributes to the resistance of salmonella to ... | 2012 | 22311927 |
| the evaluation of clusters of hospital infections due to multidrug-resistant salmonella enterica serovar typhimurium in the neonatal unit: a two-year experience. | seven clusters of hospital infection due to salmonella enterica serovar typhimurium were documented in the neonatology clinic of a children's hospital between april 2002 and march 2004. eighty-one neonates were infected. three cases were asymptomatic, 73 cases had gastroenteritis as the only clinical condition, and 5 cases had bacteremia associated with gastroenteritis. all isolates from stool and blood samples (n=86) were identified as salmonella enterica serovar typhimurium. extended-spectrum ... | 2012 | 22272451 |
| proteomic pleiotropy of opggh, an operon necessary for efficient growth of salmonella enterica serovar typhimurium under low-osmotic conditions. | salmonella enterica, a bacterial, food-borne pathogen of humans, can contaminate raw fruits and vegetables. unfortunately for consumers, the bacteria can survive in water used to wash away contaminating bacteria. the ability to survive the low-osmotic conditions of the wash water is attributed to the opggh operon that leads to the production of osmotically regulated periplasmic glucans. mutants lacking opggh grow slowly under low-osmotic conditions, but there are also unexpected traits such as a ... | 2012 | 22264073 |
| death receptor 3 is essential for generating optimal protective cd4⁺ t-cell immunity against salmonella. | the tnf receptor superfamily member death receptor 3 (dr3) exacerbates th2- and th17-cell-mediated inflammatory and autoimmune conditions, yet no role in host defence has been reported. here, we examined the role of dr3 during infection with salmonella enterica serovar typhimurium. infection resulted in protracted expression of the dr3 ligand tl1a but not the related tnf superfamily proteins ox40l or cd30l. tl1a expression was localized to splenic f4/80(+) macrophages where s. enterica typhimuri ... | 2012 | 22259035 |
| foodborne outbreak and nonmotile salmonella enterica variant, france. | we report a food-related outbreak of salmonellosis in humans caused by a nonmotile variant of salmonella enterica serotype typhimurium in france in 2009. this nonmotile variant had been circulating in laying hens but was not considered as typhimurium and consequently escaped european poultry flock regulations. | 2012 | 22257550 |
| cellulose mediates attachment of salmonella enterica serovar typhimurium to tomatoes. | fresh fruit and vegetables are important components of a healthy and balanced diet. however, they are increasingly being recognized as important vehicles for transmission of human pathogens that were traditionally classified as zoonotic. there is a significant gap in our knowledge and understanding of the mechanisms by which human pathogens colonize and survive on or in fruits and vegetables. in this study we investigated the binding of salmonella enterica to tomato fruits (solanum lycopersicum) ... | 2011 | 23761337 |
| intestinal and chronic infections: salmonella lifestyles in hostile environments. | the main disease syndromes caused by salmonella serovars in immunocompetent individuals are gastroenteritis and typhoid fever. these syndromes differ with regard to the host niches in which salmonella serovars grow and survive to ensure their transmission. during gastroenteritis, non-typhoidal salmonella serovars such as salmonella enterica serovar typhimurium (s. typhimurium) use their virulence factors to elicit acute intestinal inflammation, thereby creating a novel luminal niche. reactive ox ... | 2011 | 23761329 |
| intracellular voyeurism: examining the modulation of host cell activities bysalmonella enterica serovar typhimurium. | salmonella spp. can infect host cells by gaining entry through phagocytosis or by inducing host cell membrane ruffling that facilitates bacterial uptake. with its wide host range, salmonella enterica serovar typhimurium has proven to be an important model organism for studying intracellular bacterial pathogenesis. upon entry into host cells, serovar typhimurium typically resides within a membrane-bound compartment termed the salmonella-containing vacuole (scv). from the scv, serovar typhimurium ... | 2005 | 26443522 |