| a novel anti-microbial function for a familiar rab gtpase. | salmonella enterica is a bacterial pathogen that closely interacts with its host and replicates intracellularly. it has evolved the ability to create an intracellular membrane vacuole where it can survive and replicate. the nature of the salmonella vacuole is still poorly understood, and although it has some features in common with lysosomes, it serves as a suitable niche for its survival. in contrast to broad-host salmonella enterica serovars, salmonella enterica serovar typhi (s. typhi) is a h ... | 2013 | 24321888 |
| a novel antisense rna from the salmonella virulence plasmid pslt expressed by non-growing bacteria inside eukaryotic cells. | bacterial small rnas (srnas) are regulatory molecules playing relevant roles in response to environmental changes, stressful conditions and pathogenesis. the intracellular bacterial pathogen salmonella enterica serovar typhimurium (s. typhimurium) is known to regulate expression of some srnas during colonization of fibroblasts. here, we characterize a previously unknown srna encoded in the s. typhimurium pslt virulence plasmid that is specifically up-regulated by non-growing dormant bacteria per ... | 2013 | 24205037 |
| atg16l1 is required for autophagy in intestinal epithelial cells and protection of mice from salmonella infection. | intestinal epithelial cells aid in mucosal defense by providing a physical barrier against entry of pathogenic bacteria and secreting antimicrobial peptides (amps). autophagy is an important component of immune homeostasis. however, little is known about its role in specific cell types during bacterial infection in vivo. we investigated the role of autophagy in the response of intestinal epithelial and antigen-presenting cells to salmonella infection in mice. | 2013 | 23973919 |
| a bacterial virulence protein promotes pathogenicity by inhibiting the bacterium's own f1fo atp synthase. | several intracellular pathogens, including salmonella enterica and mycobacterium tuberculosis, require the virulence protein mgtc to survive within macrophages and to cause a lethal infection in mice. we now report that, unlike secreted virulence factors that target the host vacuolar atpase to withstand phagosomal acidity, the mgtc protein acts on salmonella's own f1fo atp synthase. this complex couples proton translocation to atp synthesis/hydrolysis and is required for virulence. we establish ... | 2013 | 23827679 |
| quantification of the effects of antibodies on the extra- and intracellular dynamics of salmonella enterica. | antibodies are known to be essential in controlling salmonella infection, but their exact role remains elusive. we recently developed an in vitro model to investigate the relative efficiency of four different human immunoglobulin g (igg) subclasses in modulating the interaction of the bacteria with human phagocytes. our results indicated that different igg subclasses affect the efficacy of salmonella uptake by human phagocytes. in this study, we aim to quantify the effects of igg on intracellula ... | 2013 | 23235264 |
| 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 ... | 2014 | 25267669 |
| an inducible and secreted eukaryote-like serine/threonine kinase of salmonella enterica serovar typhi promotes intracellular survival and pathogenesis. | eukaryote-like serine/threonine kinases (estks) constitute an important family of bacterial virulence factors. genome analysis had predicted putative estks in salmonella enterica serovar typhi, although their functional characterization and the elucidation of their role in pathogenesis are still awaited. we show here that the primary sequence and secondary structure of the t4519 locus of salmonella typhi ty2 have all the signatures of eukaryotic superfamily kinases. t4519 encodes a ∼39-kda prote ... | 2014 | 25404028 |
| the role of clpp, rpos and csra in growth and filament formation of salmonella enterica serovar typhimurium at low temperature. | salmonellae are food-borne pathogens of great health and economic importance. to pose a threat to humans, salmonellae normally have to cope with a series of stressful conditions in the food chain, including low temperature. in the current study, we evaluated the importance of the clp proteolytic complex and the carbon starvation protein, csra, for the ability of salmonella typhimurium to grow at low temperature. | 2014 | 25123657 |
| identification of metabolic pathways essential for fitness of salmonella typhimurium in vivo. | bacterial infections remain a threat to human and animal health worldwide, and there is an urgent need to find novel targets for intervention. in the current study we used a computer model of the metabolic network of salmonella enterica serovar typhimurium and identified pairs of reactions (cut sets) predicted to be required for growth in vivo. we termed such cut sets synthetic auxotrophic pairs. we tested whether these would reveal possible combined targets for new antibiotics by analyzing the ... | 2014 | 24992475 |
| the salmonella spi1 virulence regulatory protein hild directly activates transcription of the flagellar master operon flhdc. | infection of intestinal epithelial cells is dependent on the salmonella enterica serovar typhimurium pathogenicity island 1 (spi1)-encoded type iii injectisome system and flagellar motility. thus, the expression of virulence and flagellar genes is subject to tight regulatory control mechanisms in order to ensure the correct spatiotemporal production of the respective gene products. in this work, we reveal a new level of cross-regulation between the spi1 and flagellar regulatory systems. transpos ... | 2014 | 24488311 |
| control of a salmonella virulence operon by proline-charged trna(pro). | the intracellular pathogen salmonella enterica serovar typhimurium requires the mgtc gene to cause disease. the mgtc transcript includes a long leader region that harbors a short proline codon-rich orf--termed mgtp--the translation of which is predicted to favor formation of one of two alternative stem-loop structures. we now report that the mgtp proline codons are critical for expression of the mgtc coding region inside host cells, for salmonella survival inside macrophages, and for virulence i ... | 2014 | 24516160 |
| cyclic rhamnosylated elongation factor p establishes antibiotic resistance in pseudomonas aeruginosa. | elongation factor p (ef-p) is a ubiquitous bacterial protein that is required for the synthesis of poly-proline motifs during translation. in escherichia coli and salmonella enterica, the posttranslational β-lysylation of lys34 by the poxa protein is critical for ef-p activity. poxa is absent from many bacterial species such as pseudomonas aeruginosa, prompting a search for alternative ef-p posttranslation modification pathways. structural analyses of p. aeruginosa ef-p revealed the attachment o ... | 2015 | 26060278 |
| a diverse range of bacterial and eukaryotic chitinases hydrolyzes the lacnac (galβ1-4glcnac) and lacdinac (galnacβ1-4glcnac) motifs found on vertebrate and insect cells. | there is emerging evidence that chitinases have additional functions beyond degrading environmental chitin, such as involvement in innate and acquired immune responses, tissue remodeling, fibrosis, and serving as virulence factors of bacterial pathogens. we have recently shown that both the human chitotriosidase and a chitinase from salmonella enterica serovar typhimurium hydrolyze lacnac from galβ1-4glcnacβ-tetramethylrhodamine (lacnac-tmr (galβ1-4glcnacβ(ch2)8conh(ch2)2nhco-tmr)), a fluorescen ... | 2015 | 25561735 |
| human genome-wide rnai screen for host factors that facilitate salmonella invasion reveals a role for potassium secretion in promoting internalization. | salmonella enterica can actively invade the gastro-intestinal epithelium. this frequently leads to diarrheal disease, and also gives the pathogen access to phagocytes that can serve as vehicles for dissemination into deeper tissue. the ability to invade host cells is also important in maintaining the carrier state. while much is known about the bacterial factors that promote invasion, relatively little is known about the host factors involved. to gain insight into how salmonella enterica serovar ... | 2016 | 27880807 |
| salmonella effectors ssef and sseg interact with mammalian protein acbd3 (gcp60) to anchor salmonella-containing vacuoles at the golgi network. | following infection of mammalian cells, salmonella enterica serovar typhimurium (s typhimurium) replicates within membrane-bound compartments known as salmonella-containing vacuoles (scvs). the salmonella pathogenicity island 2 type iii secretion system (spi-2 t3ss) translocates approximately 30 different effectors across the vacuolar membrane. ssef and sseg are two such effectors that are required for scvs to localize close to the golgi network in infected epithelial cells. in a yeast two-hybri ... | 2016 | 27406559 |
| a trade-off between the fitness cost of functional integrases and long-term stability of integrons. | horizontal gene transfer (hgt) plays a major role in bacterial microevolution as evident from the rapid emergence and spread of antimicrobial drug resistance. few studies have however addressed the population dynamics of newly imported genetic elements after hgt. here, we show that newly acquired class-1 integrons from salmonella enterica serovar typhimurium and acinetobacter baumannii, free of associated transposable elements, strongly reduce host fitness in acinetobacter baylyi. insertional in ... | 2012 | 23209414 |
| functional analysis of the genes encoding diaminopropionate ammonia lyase in escherichia coli and salmonella enterica serovar typhimurium. | diaminopropionate ammonia lyase (dapal) is a pyridoxal-5'phosphate (plp)-dependent enzyme that catalyzes the conversion of diaminopropionate (dap) to pyruvate and ammonia and plays an important role in cell metabolism. we have investigated the role of the ygex gene of escherichia coli k-12 and its ortholog, stm1002, in salmonella enterica serovar typhimurium lt2, presumed to encode dapal, in the growth kinetics of the bacteria. while salmonella typhimurium lt2 could grow on dl-dap as a sole carb ... | 2012 | 22904288 |
| effect of systemic infection induced by pseudomonas aeruginosa on the brain uptake of colistin in mice. | in view of reports of colistin-induced neurotoxicity in infected patients, the aim of this study was to assess whether the integrity of the blood-brain barrier (bbb) and the brain uptake of colistin are altered in the presence of systemic pseudomonas aeruginosa infection. bacteremia was confirmed 8 h after intramuscular administration of p. aeruginosa atcc 27853 to swiss outbred mice, at which time a single subcutaneous dose of colistin sulfate (40 mg/kg of body weight) or an intravenous dose of ... | 2012 | 22850514 |
| colistin resistance in escherichia coli and salmonella enterica strains isolated from swine in brazil. | reports about acquired resistance to colistin in different bacteria species are increasing, including e. coli of animal origin, but reports of resistance in wild s. enterica of different serotypes from swine are not found in the literature. results obtained with one hundred and twenty-six e. coli strains from diseased swine and one hundred and twenty-four s. enterica strains from diseased and carrier swine showed a frequency of 6.3% and 21% of colistin-resistant strains, respectively. when compa ... | 2012 | 22973166 |
| impact of antibiotic mic on infection outcome in patients with susceptible gram-negative bacteria: a systematic review and meta-analysis. | the objective of this study was to analyze the impact of mic values within the susceptible range of antibiotics on the outcomes of patients with gram-negative infections. the pubmed and scopus electronic databases were searched. we identified 13 articles (1,469 patients) that studied the impact of antibiotic mics on the outcomes of infections; β-lactams were studied in 10 of them. infections due to salmonella enterica strains with high fluoroquinolone mics were associated with more treatment fai ... | 2012 | 22615292 |
| factors associated with encephalopathy in patients with salmonella enterica serotype typhi bacteremia presenting to a diarrheal hospital in dhaka, bangladesh. | to characterize clinical correlates of typhoid fever-associated encephalopathy, we performed a retrospective chart review of patients with salmonella enterica serotype typhi bacteremia who were hospitalized at the international centre for diarrhoeal disease research, bangladesh, from february of 2009 to june of 2011. of 207 patients bacteremic with salmonella typhi who were ≥ 5 years of age, we identified 43 (21%) patients with encephalopathy. univariate analysis revealed that patients with ence ... | 2012 | 22492156 |
| antimicrobial activity of amazonian medicinal plants. | the aqueous extracts of currently utilized amazonian medicinal plants were assayed in vitro searching for antimicrobial activity against human and animal pathogenic microorganisms. | 2013 | 23961431 |
| discrimination of enterobacteriaceae and non-fermenting gram negative bacilli by maldi-tof mass spectrometry. | discrimination of enterobacteriaceae and non-fermenting gram negative bacilli by maldi-tof mass spectrometry matrix assisted laser desorption/ionization time of flight mass spectrometry (maldi-tof ms) has proven to be an effective identification tool in medical microbiology. discrimination to subspecies or serovar level has been found to be challenging using commercially available identification software. by forming our own reference database and using alternative analysis methods, we could reli ... | 2013 | 23919091 |
| purification and host specificity of predatory halobacteriovorax isolates from seawater. | halobacteriovorax (formerly bacteriovorax) is a small predatory bacterium found in the marine environment and modulates bacterial pathogens in shellfish. four strains of halobacteriovorax originally isolated in vibrio parahaemolyticus o3:k6 host cells were separated from their prey by an enrichment-filtration-dilution technique for specificity testing in other bacteria. this technique was essential, since 0.45-μm filtration alone was unable to remove infectious vibrio minicells, as determined by ... | 2016 | 26590288 |
| complete fiber structures of complex trimeric autotransporter adhesins conserved in enterobacteria. | trimeric autotransporter adhesins (taas) are modular, highly repetitive surface proteins that mediate adhesion to host cells in a broad range of gram-negative pathogens. although their sizes may differ by more than one order of magnitude, they all follow the same basic head-stalk-anchor architecture, where the head mediates adhesion and autoagglutination, the stalk projects the head from the bacterial surface, and the anchor provides the export function and attaches the adhesin to the bacterial ... | 2012 | 23213248 |
| bacterial coinfections in travelers with malaria: rationale for antibiotic therapy. | malaria predisposes children in areas where malaria is endemic to concurrent bacteremia, often with severe outcomes. the importance of bacterial coinfections in patients diagnosed with malaria in nonendemic settings has, however, not been reported. a retrospective analysis of microbiology data was performed in 755 travelers diagnosed with malaria in sweden. bacterial cultures from blood and other locations were correlated to clinical outcome and antibiotic treatment. blood cultures were drawn fr ... | 2013 | 23052321 |
| host specificity of bacterial pathogens. | most pathogens are able to infect multiple hosts but some are highly adapted to a single-host species. a detailed understanding of the basis of host specificity can provide important insights into molecular pathogenesis, the evolution of pathogenic microbes, and the potential for pathogens to cross the species barrier to infect new hosts. comparative genomics and the development of humanized mouse models have provided important new tools with which to explore the basis of generalism and speciali ... | 2013 | 24296346 |
| dimethyl adenosine transferase (ksga) deficiency in salmonella enterica serovar enteritidis confers susceptibility to high osmolarity and virulence attenuation in chickens. | dimethyl adenosine transferase (ksga) performs diverse roles in bacteria, including ribosomal maturation and dna mismatch repair, and synthesis of ksga is responsive to antibiotics and cold temperature. we previously showed that a ksga mutation in salmonella enterica serovar enteritidis results in impaired invasiveness in human and avian epithelial cells. in this study, we tested the virulence of a ksga mutant (the ksga::tn5 mutant) of s. enteritidis in orally challenged 1-day-old chickens. the ... | 2013 | 24123731 |
| absence of platelet endothelial cell adhesion molecule 1, pecam-1/cd31, in vivo increases resistance to salmonella enterica serovar typhimurium in mice. | pecam-1/cd31 is known to regulate inflammatory responses and exhibit pro- and anti-inflammatory functions. this study was designed to determine the functional role of pecam-1 in susceptibility to murine primary in vivo infection with salmonella enterica serovar typhimurium and in in vitro inflammatory responses of peritoneal macrophages. lectin profiling showed that cellular pecam-1 and recombinant human pecam-1-ig chimera contain high levels of mannose sugars and n-acetylglucosamine. consistent ... | 2013 | 23509149 |
| computational analysis of bacterial rna-seq data. | recent advances in high-throughput rna sequencing (rna-seq) have enabled tremendous leaps forward in our understanding of bacterial transcriptomes. however, computational methods for analysis of bacterial transcriptome data have not kept pace with the large and growing data sets generated by rna-seq technology. here, we present new algorithms, specific to bacterial gene structures and transcriptomes, for analysis of rna-seq data. the algorithms are implemented in an open source software system c ... | 2013 | 23716638 |
| the vi capsular polysaccharide enables salmonella enterica serovar typhi to evade microbe-guided neutrophil chemotaxis. | salmonella enterica serovar typhi (s. typhi) causes typhoid fever, a disseminated infection, while the closely related pathogen s. enterica serovar typhimurium (s. typhimurium) is associated with a localized gastroenteritis in humans. here we investigated whether both pathogens differ in the chemotactic response they induce in neutrophils using a single-cell experimental approach. surprisingly, neutrophils extended chemotactic pseudopodia toward escherichia coli and s. typhimurium, but not towar ... | 2014 | 25101794 |
| c-terminal domain swapping of ssb changes the size of the ssdna binding site. | single-stranded dna-binding protein (ssb) plays an important role in dna metabolism, including dna replication, repair, and recombination, and is therefore essential for cell survival. bacterial ssb consists of an n-terminal ssdna-binding/oligomerization domain and a flexible c-terminal protein-protein interaction domain. we characterized the ssdna-binding properties of klebsiella pneumoniae ssb (kpssb), salmonella enterica serovar typhimurium lt2 ssb (stssb), pseudomonas aeruginosa pao1 ssb (pa ... | 2014 | 25162017 |
| resistance to β-lactam antibiotics conferred by point mutations in penicillin-binding proteins pbp3, pbp4 and pbp6 in salmonella enterica. | penicillin-binding proteins (pbps) are enzymes responsible for the polymerization of the glycan strand and the cross-linking between glycan chains as well as the target proteins for β-lactam antibiotics. mutational alterations in pbps can confer resistance either by reducing binding of the antibiotic to the active site or by evolving a β-lactamase activity that degrades the antibiotic. as no systematic studies have been performed to examine the potential of all pbps present in one bacterial spec ... | 2014 | 24810745 |
| inflammasome activation causes dual recruitment of nlrc4 and nlrp3 to the same macromolecular complex. | pathogen recognition by nucleotide-binding oligomerization domain-like receptor (nlr) results in the formation of a macromolecular protein complex (inflammasome) that drives protective inflammatory responses in the host. it is thought that the number of inflammasome complexes forming in a cell is determined by the number of nlrs being activated, with each nlr initiating its own inflammasome assembly independent of one another; however, we show here that the important foodborne pathogen salmonell ... | 2014 | 24803432 |
| 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 ... | 2014 | 25253912 |
| the cytokine il-22 promotes pathogen colonization by suppressing related commensal bacteria. | interleukin-22 (il-22) is highly induced in response to infections with a variety of pathogens, and its main functions are considered to be tissue repair and host defense at mucosal surfaces. here we showed that il-22 has a unique role during infection in that its expression suppressed the intestinal microbiota and enhanced the colonization of a pathogen. il-22 induced the expression of antimicrobial proteins, including lipocalin-2 and calprotectin, which sequester essential metal ions from micr ... | 2014 | 24508234 |
| presumable role of outer membrane proteins of salmonella containing sialylated lipopolysaccharides serovar ngozi, sv. isaszeg and subspecies arizonae in determining susceptibility to human serum. | the o48 group comprises salmonella bacteria containing sialic acid in the lipopolysaccharide (lps). bacteria with sialylated surface structures are described as pathogens that avoid immunological response of the host by making similar their surface antigens to the host's tissues (molecular mimicry). it is known that the smooth-type lps of salmonella enterica and outer membrane proteins (omp) pgte, pagc and rck mediate serum resistant phenotype by affecting complement system (c). the aim of this ... | 2015 | 26185527 |
| effects of norspermidine and spermidine on biofilm formation by potentially pathogenic escherichia coli and salmonella enterica wild-type strains. | polyamines are present in all living cells. in bacteria, polyamines are involved in a variety of functions, including biofilm formation, thus indicating that polyamines may have potential in the control of unwanted biofilm. in the present study, the effects of the polyamines norspermidine and spermidine on biofilms of 10 potentially pathogenic wild-type strains of escherichia coli serotype o103:h2, salmonella enterica subsp. enterica serovar typhimurium, and s. enterica serovar agona were invest ... | 2015 | 25595767 |
| outer membrane vesicles from flagellin-deficient salmonella enterica serovar typhimurium induce cross-reactive immunity and provide cross-protection against heterologous salmonella challenge. | outer membrane vesicles (omvs) isolated from salmonella typhimurium are potentially useful for developing subunit vaccines because of high immunogenicity and protective efficacy. however, flagella might remain in omv pellets following omv purification, resulting in non-essential immune responses and counteraction of bacterial protective immune responses when developing a vaccine against infection of multiple serotypes salmonella. in this study, a flagellin-deficient s. typhimurium mutant was con ... | 2016 | 27698383 |
| inhibition of bacterial virulence: drug-like molecules targeting the salmonella enterica phop response regulator. | two-component signal transduction (tcst) is the predominant signaling scheme used in bacteria to sense and respond to environmental changes in order to survive and thrive. a typical tcst system consists of a sensor histidine kinase to detect external signals and an effector response regulator to respond to external changes. in the signaling scheme, the histidine kinase phosphorylates and activates the response regulator, which functions as a transcription factor to modulate gene expression. one ... | 2012 | 22339993 |
| glycoconjugate vaccine strategies for protection against invasive salmonella infections. | salmonella enterica serovars typhi and paratyphi a and b and certain non-typhoidal salmonella enterica (nts) serovars are important causes of invasive salmonella disease worldwide. nts serovars typhimurium and enteritidis typically cause gastroenteritis in healthy children and adults in industrialized countries but in certain hosts (e.g., young infants, the elderly, immunocompromised individuals) they also cause invasive infections. these two serovars also cause invasive disease in infants and y ... | 2012 | 22370510 |
| comparative sequence, structure and redox analyses of klebsiella pneumoniae dsba show that anti-virulence target dsba enzymes fall into distinct classes. | bacterial dsba enzymes catalyze oxidative folding of virulence factors, and have been identified as targets for antivirulence drugs. however, dsba enzymes characterized to date exhibit a wide spectrum of redox properties and divergent structural features compared to the prototypical dsba enzyme of escherichia coli dsba (ecdsba). nonetheless, sequence analysis shows that dsbas are more highly conserved than their known substrate virulence factors, highlighting the potential to inhibit virulence a ... | 2013 | 24244651 |
| salmonella typhi omps1 and omps2 porins are potent protective immunogens with adjuvant properties. | salmonella enterica serovar typhi (s. typhi) is the causal agent of typhoid fever, a disease that primarily affects developing countries. various antigens from this bacterium have been reported to be targets of the immune response. recently, the s. typhi genome has been shown to encode two porins--omps1 and omps2--which are expressed at low levels under in vitro culture conditions. in this study, we demonstrate that immunizing mice with either omps1 or omps2 induced production of specific, long- ... | 2013 | 23432484 |
| design of glycoconjugate vaccines against invasive african salmonella enterica serovar typhimurium. | nontyphoidal salmonellae, particularly salmonella enterica serovar typhimurium, are a major cause of invasive disease in africa, affecting mainly young children and hiv-infected individuals. glycoconjugate vaccines provide a safe and reliable strategy against invasive polysaccharide-encapsulated pathogens, and lipopolysaccharide (lps) is a target of protective immune responses. with the aim of designing an effective vaccine against s. typhimurium, we have synthesized different glycoconjugates, b ... | 2014 | 25547792 |
| the molecular epidemiological characteristics and genetic diversity of salmonella typhimurium in guangdong, china, 2007-2011. | salmonella enterica serovar typhimurium is the most important serovar associated with human salmonellosis worldwide. here we aimed to explore the molecular epidemiology and genetic characteristics of this serovar in guangdong, china. | 2014 | 25380053 |
| effect of human immunodeficiency virus infection on plasma bactericidal activity against salmonella enterica serovar typhimurium. | individuals with human immunodeficiency virus (hiv) infection have increased susceptibility to invasive disease caused by salmonella enterica serovar typhimurium. studies from africa have suggested that this susceptibility is related in part to the development of a high level of lipopolysaccharide (lps)-specific igg that is able to inhibit the killing of s. typhimurium by bactericidal antibodies in healthy individuals. to explore this issue further, we examined the bactericidal activity against ... | 2014 | 25121777 |
| decoration of outer membrane vesicles with multiple antigens by using an autotransporter approach. | outer membrane vesicles (omvs) are spherical nanoparticles that naturally shed from gram-negative bacteria. they are rich in immunostimulatory proteins and lipopolysaccharide but do not replicate, which increases their safety profile and renders them attractive vaccine vectors. by packaging foreign polypeptides in omvs, specific immune responses can be raised toward heterologous antigens in the context of an intrinsic adjuvant. antigens exposed at the vesicle surface have been suggested to elici ... | 2014 | 25038093 |
| transient darwinian selection in salmonella enterica serovar paratyphi a during 450 years of global spread of enteric fever. | multiple epidemic diseases have been designated as emerging or reemerging because the numbers of clinical cases have increased. emerging diseases are often suspected to be driven by increased virulence or fitness, possibly associated with the gain of novel genes or mutations. however, the time period over which humans have been afflicted by such diseases is only known for very few bacterial pathogens, and the evidence for recently increased virulence or fitness is scanty. has darwinian (diversif ... | 2014 | 25092320 |
| structural insights into the lipoprotein outer membrane regulator of penicillin-binding protein 1b. | in bacteria, the synthesis of the protective peptidoglycan sacculus is a dynamic process that is tightly regulated at multiple levels. recently, the lipoprotein co-factor lpob has been found essential for the in vivo function of the major peptidoglycan synthase pbp1b in enterobacteriaceae. here, we reveal the crystal structures of salmonella enterica and escherichia coli lpob. the lpob protein can be modeled as a ball and tether, consisting of a disordered n-terminal region followed by a compact ... | 2014 | 24808177 |
| salmonella enterica serovar virchow meningitis in a young man in italy: a case report. | salmonella enterica is a leading cause of foodborne infections worldwide and includes more than 2500 different serovars, causing primarily gastroenteritis. however, the infection may occur elsewhere and produce characteristic clinical syndromes. meningitis is a rare complication that occurs in less than 1% of clinical salmonellosis. | 2014 | 24884674 |
| serum bactericidal assays to evaluate typhoidal and nontyphoidal salmonella vaccines. | invasive salmonella infections for which improved or new vaccines are being developed include enteric fever caused by salmonella enterica serovars typhi, paratyphi a, and paratyphi b and sepsis and meningitis in young children in sub-saharan africa caused by nontyphoidal salmonella (nts) serovars, particularly s. enterica serovars typhimurium and enteritidis. assays are needed to measure functional antibodies elicited by the new vaccines to assess their immunogenicities and potential protective ... | 2014 | 24623629 |
| crispr is an optimal target for the design of specific pcr assays for salmonella enterica serotypes typhi and paratyphi a. | serotype-specific pcr assays targeting salmonella enterica serotypes typhi and paratyphi a, the causal agents of typhoid and paratyphoid fevers, are required to accelerate formal diagnosis and to overcome the lack of typing sera and, in some situations, the need for culture. however, the sensitivity and specificity of such assays must be demonstrated on large collections of strains representative of the targeted serotypes and all other bacterial populations producing similar clinical symptoms. | 2014 | 24498453 |
| development of a taqman array card for acute-febrile-illness outbreak investigation and surveillance of emerging pathogens, including ebola virus. | acute febrile illness (afi) is associated with substantial morbidity and mortality worldwide, yet an etiologic agent is often not identified. convalescent-phase serology is impractical, blood culture is slow, and many pathogens are fastidious or impossible to cultivate. we developed a real-time pcr-based taqman array card (tac) that can test six to eight samples within 2.5 h from sample to results and can simultaneously detect 26 afi-associated organisms, including 15 viruses (chikungunya, crime ... | 2015 | 26491176 |
| clinical and microbiological features of salmonella meningitis in a south african population, 2003-2013. | the clinical and microbiological characteristics of nontyphoidal salmonella (nts) meningitis in south africa, where human immunodeficiency virus (hiv) prevalence is high (approximately 15% in persons ≥15 years of age), were reviewed. | 2015 | 26449942 |
| monoclonal antibodies of a diverse isotype induced by an o-antigen glycoconjugate vaccine mediate in vitro and in vivo killing of african invasive nontyphoidal salmonella. | nontyphoidal salmonella (nts), particularly salmonella enterica serovars typhimurium and enteritidis, is responsible for a major global burden of invasive disease with high associated case-fatality rates. we recently reported the development of a candidate o-antigen-crm197 glycoconjugate vaccine against s. typhimurium. here, using a panel of mouse monoclonal antibodies generated by the vaccine, we examined the relative efficiency of different antibody isotypes specific for the o:4 antigen of s. ... | 2015 | 26169269 |
| comparative growth analysis of capsulated (vi+) and acapsulated (vi-) salmonella typhi isolates in human blood. | salmonella enterica serovar typhi (s. typhi) is a human restricted pathogen. it biosynthesizes a virulence capsular polysaccharide named as vi antigen. s. typhi regulates expression of genes involved in the biosynthesis of vi antigen in response to osmolarity. beside vi-positive isolates, vi-negative (acapsulated) isolates are also pathogenic. however, vi-positive isolates are more prevalent. the present study was planned to investigate comparative growth of vi-positive and vi-negative s. typhi ... | 2015 | 26417360 |
| the stm4195 gene product (pans) transports coenzyme a precursors in salmonella enterica. | coenzyme a (coa) is a ubiquitous coenzyme involved in fundamental metabolic processes. coa is synthesized from pantothenic acid by a pathway that is largely conserved among bacteria and eukaryotes and consists of five enzymatic steps. while higher organisms, including humans, must scavenge pantothenate from the environment, most bacteria and plants are capable of de novo pantothenate biosynthesis. in salmonella enterica, precursors to pantothenate can be salvaged, but subsequent intermediates ar ... | 2015 | 25645561 |
| serum bactericidal assay for the evaluation of typhoid vaccine using a semi-automated colony-counting method. | typhoid fever, mainly caused by salmonella enterica serovar typhi (s. typhi), is a life-threatening disease, mostly in developing countries. enzyme-linked immunosorbent assay (elisa) is widely used to quantify antibodies against s. typhi in serum but does not provide information about functional antibody titers. although the serum bactericidal assay (sba) using an agar plate is often used to measure functional antibody titers against various bacterial pathogens in clinical specimens, it has rare ... | 2016 | 27216239 |
| toll-like receptor activation by generalized modules for membrane antigens from lipid a mutants of salmonella enterica serovars typhimurium and enteritidis. | invasive nontyphoidal salmonella (ints) disease is a neglected disease with high mortality in children and hiv-positive individuals in sub-saharan africa, caused primarily by africa-specific strains of salmonella enterica serovars typhimurium and enteritidis. a vaccine using gmma (generalized modules for membrane antigens) froms.typhimurium ands.enteritidis containing lipid a modifications to reduce potential in vivo reactogenicity is under development. gmma with penta-acylated lipid a showed th ... | 2016 | 26865597 |
| the promoter architectural landscape of the salmonella phop regulon. | the dna-binding protein phop controls virulence and mg²⁺ homeostasis in the gram-negative pathogen salmonella enterica serovar typhimurium. phop regulates expression of a large number of genes that differ both in their ancestry and in the biochemical functions and physiological roles of the encoded products. this suggests that phop-regulated genes are differentially expressed. to understand how a bacterial activator might generate varied gene expression behaviour, we investigated the cis-acting ... | 2012 | 22435712 |
| a naturally occurring single nucleotide polymorphism in the salmonella spi-2 type iii effector srfh/ssei controls early extraintestinal dissemination. | cd18 expressing phagocytes associated with the gastro-intestinal (gi) epithelium can shuttle salmonella directly into the bloodstream within a few minutes following microbial ingestion. we have previously demonstrated that salmonella controls the cd18 pathway to deeper tissue, manipulating the migratory properties of infected cells as an unappreciated component of its pathogenesis. we have observed that one type iii effector, srfh (also called ssei) that salmonella secretes into infected phagocy ... | 2012 | 23028876 |
| invasive non-typhoidal salmonella disease: an emerging and neglected tropical disease in africa. | invasive strains of non-typhoidal salmonellae have emerged as a prominent cause of bloodstream infection in african adults and children, with an associated case fatality of 20-25%. the clinical presentation of invasive non-typhoidal salmonella disease in africa is diverse: fever, hepatosplenomegaly, and respiratory symptoms are common, and features of enterocolitis are often absent. the most important risk factors are hiv infection in adults, and malaria, hiv, and malnutrition in children. a dis ... | 2012 | 22587967 |
| posttranslational maturation of the invasion acyl carrier protein of salmonella enterica serovar typhimurium requires an essential phosphopantetheinyl transferase of the fatty acid biosynthesis pathway. | salmonella pathogenicity island 1 (spi-1) carries genes required for the formation of a type 3 secretion system, which is necessary for the invasion process of salmonella. among the proteins encoded by spi-1 is iacp, a homolog of acyl carrier proteins. acyl carrier proteins are mainly involved in fatty acid biosynthesis, and they require posttranslational maturation by addition of a 4'-phosphopantetheine prosthetic group to be functional. in this study, we analyzed iacp maturation in vivo. by pe ... | 2013 | 23893113 |
| genome and transcriptome adaptation accompanying emergence of the definitive type 2 host-restricted salmonella enterica serovar typhimurium pathovar. | salmonella enterica serovar typhimurium definitive type 2 (dt2) is host restricted to columba livia (rock or feral pigeon) but is also closely related to s. typhimurium isolates that circulate in livestock and cause a zoonosis characterized by gastroenteritis in humans. dt2 isolates formed a distinct phylogenetic cluster within s. typhimurium based on whole-genome-sequence polymorphisms. comparative genome analysis of dt2 94-213 and s. typhimurium sl1344, dt104, and d23580 identified few differe ... | 2013 | 23982073 |
| the feoc protein leads to high cellular levels of the fe(ii) transporter feob by preventing ftsh protease regulation of feob in salmonella enterica. | in the gammaproteobacteria, the feoa, feob, and feoc proteins constitute the feo system, which mediates ferrous iron [fe(ii)] import. of these feo proteins, feob is an inner membrane fe(ii) transporter that is aided by the small protein feoa. however, the role of another small protein, feoc, has remained unknown. here we report that the feoc protein is necessary for feob protein-mediated fe(ii) uptake in salmonella experiencing low levels of oxygen and iron. the feoc protein was found to directl ... | 2013 | 23708131 |
| bacterial colonization of host cells in the absence of cholesterol. | reports implicating important roles for cholesterol and cholesterol-rich lipid rafts in host-pathogen interactions have largely employed sterol sequestering agents and biosynthesis inhibitors. because the pleiotropic effects of these compounds can complicate experimental interpretation, we developed a new model system to investigate cholesterol requirements in pathogen infection utilizing dhcr24(-/-) mouse embryonic fibroblasts (mefs). dhcr24(-/-) mefs lack the δ24 sterol reductase required for ... | 2013 | 23358892 |
| lipopolysaccharides belonging to different salmonella serovars are differentially capable of activating toll-like receptor 4. | salmonella enterica subsp. enterica serovar (serotype) abortusovis is a member of the enterobacteriaceae. this serotype is naturally restricted to ovine species and does not infect humans. limited information is available about the immune response of sheep to s. abortusovis. s. abortusovis, like salmonella enterica subsp. enterica serovar typhi, causes a systemic infection in which, under natural conditions, animals are not able to raise a rapid immune response. failure to induce the appropriate ... | 2014 | 25135686 |
| patterns of expression and translocation of the ubiquitin ligase slrp in salmonella enterica serovar typhimurium. | slrp is an e3 ubiquitin ligase that can be translocated into eukaryotic host cells by the two type iii secretion systems that are expressed by salmonella enterica serovar typhimurium and are encoded in salmonella pathogenicity islands 1 (spi1) and 2 (spi2). expression of slrp and translocation of its product were examined using lac, 3×flag, and cyaa' translational fusions. although slrp was expressed in different media, optimal expression was found under conditions that imitate the intravacuolar ... | 2014 | 25182488 |
| tc52 amino-terminal-domain dna carried by attenuated salmonella enterica serovar typhimurium induces protection against a trypanosoma cruzi lethal challenge. | in this work we immunized mice with dna encoding full-length tc52 or its amino- or carboxy-terminal (n- and c-term, respectively) domain carried by attenuated salmonella as a dna delivery system. as expected, salmonella-mediated dna delivery resulted in low antibody titers and a predominantly th1 response, as shown by the ratio of igg2a/igg1-specific antibodies. despite modest expression of tc52 in trypomastigotes, the antibodies elicited by vaccination were able to mediate lysis of the trypomas ... | 2014 | 25069980 |
| phage-host interplay: examples from tailed phages and gram-negative bacterial pathogens. | complex interactions between bacteriophages and their bacterial hosts play significant roles in shaping the structure of environmental microbial communities, not only by genetic transduction but also by modification of bacterial gene expression patterns. survival of phages solely depends on their ability to infect their bacterial hosts, most importantly during phage entry. successful dynamic adaptation of bacteriophages when facing selective pressures, such as host adaptation and resistance, dic ... | 2014 | 25191318 |
| invasion-inhibitory antibodies elicited by immunization with plasmodium vivax apical membrane antigen-1 expressed in pichia pastoris yeast. | in a recent vaccine trial performed with african children, immunization with a recombinant protein based on plasmodium falciparum apical membrane antigen 1 (ama-1) conferred a significant degree of strain-specific resistance against malaria. to contribute to the efforts of generating a vaccine against plasmodium vivax malaria, we expressed the ectodomain of p. vivax ama-1 (pvama-1) as a secreted soluble protein in the methylotrophic yeast pichia pastoris. recognized by a high percentage of sera ... | 2014 | 24379279 |
| virulence gene regulation by l-arabinose in salmonella enterica. | invasion of the intestinal epithelium is a critical step in salmonella enterica infection and requires functions encoded in the gene cluster known as salmonella pathogenicity island 1 (spi-1). expression of spi-1 genes is repressed by l-arabinose, and not by other pentoses. transport of l-arabinose is necessary to repress spi-1; however, repression is independent of l-arabinose metabolism and of the l-arabinose-responsive regulator arac. spi-1 repression by l-arabinose is exerted at a single tar ... | 2015 | 25991823 |
| host cell type-dependent translocation and phop-mediated positive regulation of the effector ssek1 of salmonella enterica. | salmonella enterica expresses two virulence-related type iii secretion systems (t3sss) encoded in salmonella pathogenicity island 1 (spi1) and spi2, respectively. ssek1 is a poorly characterized substrate of the spi2-encoded t3ss. here, we show that this effector is essential to get full virulence both in oral and intraperitoneal mice infections, in spite of not having a role in invasion or intracellular proliferation in cultured mammalian cells. in vitro, expression of ssek1 was higher in media ... | 2015 | 25972862 |
| signatures of adaptation in human invasive salmonella typhimurium st313 populations from sub-saharan africa. | two lineages of salmonella enterica serovar typhimurium (s. typhimurium) of multi-locus sequence type st313 have been linked with the emergence of invasive salmonella disease across sub-saharan africa. the expansion of these lineages has a temporal association with the hiv pandemic and antibiotic usage. we analysed the whole genome sequence of 129 st313 isolates representative of the two lineages and found evidence of lineage-specific genome degradation, with some similarities to that observed i ... | 2015 | 25803844 |
| a large family of anti-activators accompanying xyls/arac family regulatory proteins. | arac negative regulators (anr) suppress virulence genes by directly down-regulating arac/xyls members in gram-negative bacteria. in this study, we sought to investigate the distribution and molecular mechanisms of regulatory function for anrs among different bacterial pathogens. we identified more than 200 anrs distributed in diverse clinically important gram negative pathogens, including vibrio spp., salmonella spp., shigella spp., yersinia spp., citrobacter spp., enterotoxigenic (etec) and ent ... | 2016 | 27038276 |
| live and inactivated salmonella enterica serovar typhimurium stimulate similar but distinct transcriptome profiles in bovine macrophages and dendritic cells. | salmonella enterica serovar typhimurium (s. typhimurium) is a major cause of gastroenteritis in cattle and humans. dendritic cells (dc) and macrophages (mø) are major players in early immunity to salmonella, and their response could influence the course of infection. therefore, the global transcriptional response of bovine monocyte-derived dc and mø to stimulation with live and inactivated s. typhimurium was compared. both cell types mount a major response 2 h post infection, with a core common ... | 2016 | 27000047 |
| quantitation of polymyxin-lipopolysaccharide interactions using an image-based fluorescent probe. | the frequency of polymyxin-resistant pathogenic gram-negative bacteria appearing in the clinic is increasing, and the consequences are largely mediated by modification of lipopolysaccharide (lps) in the outer membrane. as polymyxins exert their antibacterial effect by binding to lps, understanding their mode of binding will prove highly valuable for new antibiotic discovery. in this study, we assess the potential of mips-9451, a fluorescent polymyxin analogue designed for imaging studies, as a f ... | 2016 | 26869441 |
| the natural antimicrobial carvacrol inhibits quorum sensing in chromobacterium violaceum and reduces bacterial biofilm formation at sub-lethal concentrations. | the formation of biofilm by bacteria confers resistance to biocides and presents problems in medical and veterinary clinical settings. here we report the effect of carvacrol, one of the major antimicrobial components of oregano oil, on the formation of biofilms and its activity on existing biofilms. assays were carried out in polystyrene microplates to observe (a) the effect of 0-0.8 mm carvacrol on the formation of biofilms by selected bacterial pathogens over 24 h and (b) the effect of 0-8 mm ... | 2014 | 24691035 |
| influence of salmonella enterica serovar typhimurium ssrb on colonization of eastern oysters (crassostrea virginica) as revealed by a promoter probe screen. | although salmonella has been isolated from 7.4 to 8.6% of domestic raw oysters, representing a significant risk for food-borne illness, little is known about the factors that influence their initial colonization by salmonella. this study tested the hypothesis that specific regulatory changes enable a portion of the invading salmonella population to colonize oysters. an in vivo promoter probe library screen identified 19 unique regions as regulated during colonization. the mutants in the nearest ... | 2015 | 26497459 |
| exposure to sub-inhibitory concentrations of cefotaxime enhances the systemic colonization of salmonella typhimurium in balb/c mice. | it has been proposed that sub-inhibitory concentrations of antibiotics play a role in virulence modulation. in this study, we evaluated the ability of salmonella enterica serovar typhimurium (hereafter s. typhimurium) to colonize systemically balb/c mice after exposure to a sub-inhibitory concentration of cefotaxime (ctx). in vivo competition assays showed a fivefold increase in systemic colonization of ctx-exposed bacteria when compared to untreated bacteria. to identify the molecular mechanism ... | 2015 | 26468132 |
| the pduq enzyme is an alcohol dehydrogenase used to recycle nad+ internally within the pdu microcompartment of salmonella enterica. | salmonella enterica uses a bacterial microcompartment (mcp) for coenzyme b(12)-dependent 1,2-propanediol (1,2-pd) utilization (pdu). the pdu mcp consists of a protein shell that encapsulates enzymes and cofactors required for metabolizing 1,2-pd as a carbon and energy source. here we show that the pduq protein of s. enterica is an iron-dependent alcohol dehydrogenase used for 1,2-pd catabolism. pduq is also demonstrated to be a new component of the pdu mcp. in addition, a series of in vivo and i ... | 2012 | 23077559 |
| novel genomic island modifies dna with 7-deazaguanine derivatives. | the discovery of ∼20-kb gene clusters containing a family of paralogs of trna guanosine transglycosylase genes, called tgta5, alongside 7-cyano-7-deazaguanine (preq0) synthesis and dna metabolism genes, led to the hypothesis that 7-deazaguanine derivatives are inserted in dna. this was established by detecting 2'-deoxy-preq0 and 2'-deoxy-7-amido-7-deazaguanosine in enzymatic hydrolysates of dna extracted from the pathogenic, gram-negative bacteria salmonella enterica serovar montevideo. these mo ... | 2016 | 26929322 |
| a connecter-like factor, caca, links rssb/rpos and the cpxr/cpxa two-component system in salmonella. | bacteria integrate numerous environmental stimuli when generating cellular responses. increasing numbers of examples describe how one two-component system (tcs) responds to signals detected by the sensor of another tcs. however, the molecular mechanisms underlying this phenomenon remain poorly defined. | 2012 | 23031642 |
| reciprocal control between a bacterium's regulatory system and the modification status of its lipopolysaccharide. | gram-negative bacteria often modify their lipopolysaccharide (lps), thereby increasing resistance to antimicrobial agents and avoidance of the host immune system. however, it is unclear how bacteria adjust the levels and activities of lps-modifying enzymes in response to the modification status of their lps. we now address this question by investigating the major regulator of lps modifications in salmonella enterica. we report that the pmra/pmrb system controls expression of a membrane peptide t ... | 2012 | 22921935 |
| accessibility and conservation: general features of bacterial small rna-mrna interactions? | bacterial small rnas (srnas) are a class of structural rnas that often regulate mrna targets via post-transcriptional base pair interactions. we determined features that discriminate functional from non-functional interactions and assessed the influence of these features on genome-wide target predictions. for this purpose, we compiled a set of 71 experimentally verified srna-target pairs from escherichia coli and salmonella enterica. furthermore, we collected full-length 5' untranslated regions ... | 2012 | 22767260 |
| automated pangenomic analysis in target selection for pcr detection and identification of bacteria by use of ssgenefinder webserver and its application to salmonella enterica serovar typhi. | with the advent of high-throughput dna sequencing, more than 4,000 bacterial genomes have been sequenced and are publicly available. we report a user-friendly web platform, ssgenefinder webserver (http://147.8.74.24/ssgenefinder/), which is updated weekly for the automated pangenomic selection of specific targets for direct pcr detection and the identification of clinically important bacteria without the need of gene sequencing. to apply the ssgenefinder webserver for identifying specific target ... | 2012 | 22442318 |
| a new protocol to detect multiple foodborne pathogens with pcr dipstick dna chromatography after a six-hour enrichment culture in a broad-range food pathogen enrichment broth. | a quick foodborne pathogen screening method after six-hour enrichment culture with a broad-range food pathogen enrichment broth is described. pathogenic factors of salmonella enterica, shigella spp., enteroinvasive escherichia coli, and enterohemorrhagic e. coli are amplified with a cocktail primer and rapid polymerase chain reaction (pcr), which finishes amplification in 30 min. the pcr amplicon was differentiated with a dipstick dna chromatography assay in 5-10 min. starting from a four- to si ... | 2013 | 24364031 |
| a small rna activates cfa synthase by isoform-specific mrna stabilization. | small rnas use a diversity of well-characterized mechanisms to repress mrnas, but how they activate gene expression at the mrna level remains not well understood. the predominant activation mechanism of hfq-associated small rnas has been translational control whereby base pairing with the target prevents the formation of an intrinsic inhibitory structure in the mrna and promotes translation initiation. here, we report a translation-independent mechanism whereby the small rna rydc selectively act ... | 2013 | 24141880 |
| genetic characterization of atypical citrobacter freundii. | the ability of a bacterial population to survive in different niches, as well as in stressful and rapidly changing environmental conditions, depends greatly on its genetic content. to survive such fluctuating conditions, bacteria have evolved different mechanisms to modulate phenotypic variations and related strategies to produce high levels of genetic diversity. laboratories working in microbiological diagnosis have shown that citrobacter freundii is very versatile in its colony morphology, as ... | 2013 | 24069274 |
| an rpos-dependent srna regulates the expression of a chaperone involved in protein folding. | small noncoding rnas (srnas) are usually expressed in the cell to face a variety of stresses. in this report we disclose the first target for sral (also known as ryja), a srna present in many bacteria, which is highly induced in stationary phase. we also demonstrate that this srna is directly transcribed by the major stress σ factor σ(s) (rpos) in salmonella enterica serovar typhimurium. we show that sral srna down-regulates the expression of the chaperone trigger factor (tf), encoded by the tig ... | 2013 | 23893734 |
| a riboswitch-regulated antisense rna in listeria monocytogenes. | riboswitches are ligand-binding elements located in 5' untranslated regions of messenger rnas, which regulate expression of downstream genes. in listeria monocytogenes, a vitamin b12-binding (b12) riboswitch was identified, not upstream of a gene but downstream, and antisense to the adjacent gene, pocr, suggesting it might regulate pocr in a nonclassical manner. in salmonella enterica, pocr is a transcription factor that is activated by 1,2-propanediol, and subsequently activates expression of t ... | 2013 | 23878253 |
| iron induces bimodal population development by escherichia coli. | bacterial biofilm formation is a complex developmental process involving cellular differentiation and the formation of intricate 3d structures. here we demonstrate that exposure to ferric chloride triggers rugose biofilm formation by the uropathogenic escherichia coli strain uti89 and by enteric bacteria citrobacter koseri and salmonella enterica serovar typhimurium. two unique and separable cellular populations emerge in iron-triggered, rugose biofilms. bacteria at the air-biofilm interface exp ... | 2013 | 23359678 |
| oxa-48 carbapenemase-producing salmonella enterica serovar kentucky isolate of sequence type 198 in a patient transferred from libya to switzerland. | here, we report a case of oxa-48-producing salmonella enterica serovar kentucky of sequence type 198 (st198) from perianal screening cultures of a patient transferred from libya to switzerland. the blaoxa-48 gene was carried by tn1999.2 and located on an ∼60-kb incl/m plasmid. this salmonella strain also possessed the blaveb-8, aac(6)-ib, tet(a), sul1, and mpha resistance genes and substitutions in gyra (ser83phe and asp87asn) and parc (ser80ile). this finding emphasizes that prompt screening st ... | 2014 | 24468781 |
| laboratory-based nationwide surveillance of antimicrobial resistance in ghana. | global efforts are underway to combat antimicrobial resistance (amr). a key target in this intervention is surveillance for local and national action. data on amr in ghana are limited, and monitoring of amr is nonexistent. we sought to generate baseline data on amr, and to assess the readiness of ghana in laboratory-based surveillance. biomedical scientists in laboratories across ghana with capacity to perform bacteriological culture were selected and trained. in-house standard operating protoco ... | 2015 | 26604806 |
| genome rearrangements can make and break small rna genes. | small rnas (srnas) are short, transcribed regulatory elements that are typically encoded in the intergenic regions (igrs) of bacterial genomes. several srnas, first recognized in escherichia coli, are conserved among enteric bacteria, but because of the regulatory roles of srnas, differences in srna repertoires might be responsible for features that differentiate closely related species. we scanned the e. coli mg1655 and salmonella enterica typhimurium genomes for nonsyntenic igrs as a potential ... | 2015 | 25601101 |
| the target spectrum of sdsr small rna in salmonella. | model enteric bacteria such as escherichia coli and salmonella enterica express hundreds of small non-coding rnas (srnas), targets for most of which are yet unknown. some srnas are remarkably well conserved, indicating that they serve cellular functions that go beyond the necessities of a single species. one of these 'core srnas' of largely unknown function is the abundant ∼100-nucleotide sdsr srna which is transcribed by the general stress σ-factor, σ(s) and accumulates in stationary phase. in ... | 2016 | 27407104 |
| mannanoligosaccharide agglutination by salmonella enterica strains isolated from carrier pigs. | type-1 fimbriae are associated with most salmonella enterica serovars and are an essential factor for host colonization. mannanoligosaccharides (mos), a prebiotic that is agglutinated by type-1 fimbriae, are proposed for the control of enterobacteria colonization and may be an alternative to salmonella control in pigs. the aim of this study was to evaluate the capability of porcine salmonella strains to adhere to mos in vitro. a total of 108 strains of salmonella sp. isolated from carrier pigs w ... | 2009 | 24031388 |
| detection and identification of salmonella enterica, escherichia coli, and shigella spp. via pcr-electrospray ionization mass spectrometry: isolate testing and analysis of food samples. | an assay to identify the common food-borne pathogens salmonella, escherichia coli, shigella, and listeria monocytogenes was developed in collaboration with ibis biosciences (a division of abbott molecular) for the plex-id biosensor system, a platform that uses electrospray ionization mass spectroscopy (esi-ms) to detect the base composition of short pcr amplicons. the new food-borne pathogen (fbp) plate has been experimentally designed using four gene segments for a total of eight amplicon targe ... | 2012 | 23001674 |
| prevalence and relative risk of cronobacter spp., salmonella spp., and listeria monocytogenes associated with the body surfaces and guts of individual filth flies. | although flies are important vectors of food-borne pathogens, there is little information to accurately assess the food-related health risk of the presence of individual flies, especially in urban areas. this study quantifies the prevalence and the relative risk of food-borne pathogens associated with the body surfaces and guts of individual wild flies. one hundred flies were collected from the dumpsters of 10 randomly selected urban restaurants. flies were identified using taxonomic keys before ... | 2012 | 22941079 |
| structural insight into the clostridium difficile ethanolamine utilisation microcompartment. | bacterial microcompartments form a protective proteinaceous barrier around metabolic enzymes that process unstable or toxic chemical intermediates. the genome of the virulent, multidrug-resistant clostridium difficile 630 strain contains an operon, eut, encoding a bacterial microcompartment with genes for the breakdown of ethanolamine and its utilisation as a source of reduced nitrogen and carbon. the c. difficile eut operon displays regulatory genetic elements and protein encoding regions in co ... | 2012 | 23144756 |