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passive protection against salmonella enterica serovar enteritidis infection from maternally derived antibodies of hens vaccinated with a ghost vaccine.this study evaluated maternal immunity against salmonella enterica serovar enteritidis acquired through the egg yolk. two-hundred 19-week-old specific pathogen free (spf) broiler breeders which were randomly divided into two groups of equal size were injected with s. enteritidis ghosts (5 × 10(9) colony forming units in 0.1 ml per hen) and phosphate-buffered saline (pbs, 0.01 mol ⋅ l(-1), ph 7.4) twice, respectively, with an interval of 2 weeks. an indirect enzyme-linked immunosorbent assay (eli ...201425200368
induction of viable but non-culturable (vbnc) state in salmonella cultured in m9 minimal medium containing high glucose.an environmental isolate of salmonella enterica serovar enteritidis (se) clone, se cl#15-1, loses its culturability during 72-h culture in m9 minimal medium containing 0.8% glucose, a concentration twice higher than that in normal m9 medium, whereas the bacterium retains its culturability in normal m9 medium. live/dead analysis using the 5-cyano-2,3-di(p-tolyl) tetrazolium chloride (ctc)-reduction assay revealed that se cells cultured in m9 medium containing 0.8% glucose died with time when in t ...201425109306
rapid whole-genome sequencing for surveillance of salmonella enterica serovar enteritidis.for salmonella enterica serovar enteritidis, 85% of isolates can be classified into 5 pulsed-field gel electrophoresis (pfge) types. however, pfge has limited discriminatory power for outbreak detection. although whole-genome sequencing has been found to improve discrimination of outbreak clusters, whether this procedure can be used in real-time in a public health laboratory is not known. therefore, we conducted a retrospective and prospective analysis. the retrospective study investigated isola ...201425062035
salmonella enterica serovar enteritidis, england and wales, 1945-2011.in england and wales, the emergence of salmonella enterica serovar enteritidis resulted in the largest and most persistent epidemic of foodborne infection attributable to a single subtype of any pathogen since systematic national microbiological surveillance was established. we reviewed 67 years of surveillance data to examine the features, underlying causes, and overall effects of s. enterica ser. enteritidis. the epidemic was associated with the consumption of contaminated chicken meat and egg ...201424960614
evaluation of viability-qpcr detection system on viable and dead salmonella serovar enteritidis.the propidium monoazide (pma) coupled with pcr (viability pcr) is used in foodborne pathogen detection in order to detect only viable bacteria. originally presented to fully remove the signal of dead bacteria, the limits of the viability pcr rapidly came out in the literature. in this study, the use of pma in a viability-qpcr (v-qpcr) was assessed on viable and dead cells of salmonella enterica subsp. enterica serovar enteritidis. the pma treatment protocol was modified (dark incubation duration ...201424927988
molecular typing of salmonella enterica serovar enteritidis isolates from food-producing animals in japan by multilocus variable-number tandem repeat analysis: evidence of clonal dissemination and replacement.salmonella enterica serovar enteritidis is a zoonotic pathogen. human infections are associated with contaminated eggs and egg products. in japan, since 1989, the incidence of food-borne disease caused by s. enteritidis has increased and a pandemic has occurred; however, little is known about changes that occurred before and after this pandemic event in the dominant lineage of isolates from food-producing animals. this study aimed to determine the s. enteritidis lineages in japan over the last f ...201424886658
characterization of multidrug-resistant salmonella enterica serovars indiana and enteritidis from chickens in eastern china.a total of 310 salmonella isolates were isolated from 6 broiler farms in eastern china, serotyped according to the kauffmann-white classification. all isolates were examined for susceptibility to 17 commonly used antimicrobial agents, representative isolates were examined for resistance genes and class i integrons using pcr technology. clonality was determined by pulsed-field gel electrophoresis (pfge). there were two serotypes detected in the 310 salmonella strains, which included 133 salmonell ...201424788434
high-quality draft whole-genome sequences of 162 salmonella enterica subsp. enterica serovar enteritidis strains isolated from diverse sources in canada.we report the high-quality draft genome sequences of 162 strains of salmonella enterica subsp. enterica serovar enteritidis representing diverse phage types and pulsed-field gel electrophoresis (pfge) profiles. the analysis of these genomes will enable the identification of markers that are useful for differentiating strains of this highly clonal serovar and will provide insights into the evolution, virulence, and epidemiology of the strains.201424786953
complete genome sequences of 16 canadian strains of salmonella enterica subsp. enterica serovar enteritidis.salmonella enterica subsp. enterica serovar enteritidis is an important zoonotic food-borne pathogen causing serious human illnesses frequently linked to poultry products. here, we report fully assembled genome sequences of 16 s. enteritidis strains with common pulsed-field gel electrophoresis (pfge) and phage types (8, 13, 13a, and 14b) that predominate in north america.201424762938
emergence and clonal dissemination of salmonella enterica serovar enteritidis causing salmonellosis in mauritius.for decades, salmonella enterica serovar enteritidis has been among the most prevalent serovars reported worldwide. however, it was rarely encountered in mauritius until 2007; since then the number of non-typhoidal salmonella serogroup o:9 (including serovar enteritidis) increased. a study was conducted to investigate the genetic relatedness between s. enteritidis isolates recovered in mauritius from food and clinical specimens (stool, blood, and exudate).201424727511
contribution of salmonella enteritidis virulence factors to intestinal colonization and systemic dissemination in 1-day-old chickens.salmonella enterica serovar enteritidis is one of the most common serovars associated with poultry and poultry product contamination in the united states. we previously identified 14 mutant strains of salmonella enteritidis phage type 4 (pt4) with significantly reduced invasiveness in human intestinal epithelial cells (caco-2), chicken macrophages (hd-11), and chicken hepatocellular epithelial cells (lmh). these included salmonella enteritidis mutants with transposon insertions in 6 newly identi ...201424706964
avra effector protein of salmonella enterica serovar enteritidis is expressed and translocated in mesenteric lymph nodes at late stages of infection in mice.salmonellosis is a major health problem worldwide. salmonella enterica serovar enteritidis (s. enteritidis) has been a primary cause of salmonella outbreaks in many countries. avra is an spi-1 effector protein involved in the enteritis pathway, with critical roles in inhibiting inflammation and apoptosis. in this work, we constructed an avra-flag-tagged strain of s. enteritidis to analyse the expression profile of avra in vitro, in cell culture and in vivo. avra expression and secretion were obs ...201424705228
effects of environmental conditions on growth and survival of salmonella in pasteurized whole egg.this study investigated the influence of three parameters (time, temperature and nacl concentration) on survival and four parameters (temperature, nacl and lysozyme concentrations and ph) on growth of salmonella enterica serovar enteritidis (s. enteritidis) in pasteurized whole egg (pwe). doehlert uniform shell design was employed to choose conditions for trials and data was fitted to polynomial models and were presented as estimated response surfaces. a model for prediction of reduction of s. e ...201424703437
selection for pro-inflammatory mediators yields chickens with increased resistance against salmonella enterica serovar enteritidis.salmonella is a leading cause of foodborne illness and can be transmitted through consumption of contaminated poultry; therefore, increasing a flock's natural resistance to salmonella could improve food safety. previously, we characterized the heterophil-mediated innate immune response of 2 parental broiler lines and f1 reciprocal crosses and showed that increased heterophil function and expression of pro-inflammatory mediators corresponds with increased resistance against diverse pathogens. a p ...201424604845
genetic diversity and evolution of salmonella enterica serovar enteritidis strains with different phage types.phage typing has been used for the epidemiological surveillance of salmonella enterica serovar enteritidis for over 2 decades. however, knowledge of the genetic and evolutionary relationships between phage types is very limited, making differences difficult to interpret. here, single nucleotide polymorphisms (snps) identified from whole-genome comparisons were used to determine the relationships between some s. enteritidis phage types (pts) commonly associated with food-borne outbreaks in the un ...201424574287
an outbreak of salmonella newport associated with mung bean sprouts in germany and the netherlands, october to november 2011.the largest salmonella enterica serovar newport outbreak (n=106) ever reported in germany occurred in october and november 2011. twenty associated cases were reported in the netherlands. the outbreak investigation included an analytical epidemiological study, molecular typing of human and food isolates and food traceback investigations. unspecified salmonella had been detected in samples of mung bean sprouts at a sprout producer (producer a) in the netherlands and mung bean sprouts contaminated ...201424434173
role of the flagellar basal-body protein, flgc, in the binding of salmonella enterica serovar enteritidis to host cells.salmonella enterica serovar enteritidis (se) infection in humans is often associated with the consumption of contaminated poultry products. binding of the bacterium to the intestinal mucosa is a major pathogenic mechanism of salmonella in poultry. transposon mutagenesis identified flgc as a potential binding mutant of se. therefore, we hypothesize flgc which plays a significant role in the binding ability of se to the intestinal mucosa of poultry. to test our hypothesis, we created a mutant of s ...201424420330
salmonella enterica serovar enteritidis modulates intestinal epithelial mir-128 levels to decrease macrophage recruitment via macrophage colony-stimulating factor.the mechanism underlying the ability of virulent salmonella organisms to escape clearance by macrophages is incompletely understood. here, we report a novel mechanism by which salmonella escapes macrophages.201424415783
the influences of se infection on layers' production performance, egg quality and blood biochemical indicators.salmonella enterica serovar enteritidis (se), as a major cause of foodborn illness, infects humans mainly through the egg. however, the symptom of laying hens usually is not typical and hard to diagnosis. in the present study, it is studied that the influences of se infection on layers' performance, egg quality and blood biochemical indicators. it will help us to improve the strategy to control se infection in commercial layers. one hundred layers at 20 wk of age were divided into 2 groups, 60 h ...201424405886
critical role of glycogen synthase kinase-3β in regulating the avian heterophil response to salmonella enterica serovar enteritidis.a microarray-assisted gene expression screen of chicken heterophils revealed glycogen synthase kinase-3β (gsk-3β), a multifunctional ser/thr kinase, to be consistently upregulated 30-180 min following stimulation with salmonella enterica serovar enteritidis (s. enteritidis). the present study was designed to delineate the role of gsk-3β in regulating the innate function of chicken heterophils in response to s. enteritidis exposure. using a specific gsk-3β elisa assay, 30 min after infection with ...201426664916
phage and mlva typing of salmonella enteritidis isolated from layers and humans in belgium from 2000-2010, a period in which vaccination of laying hens was introduced.the aim of the study was to characterize isolates of salmonella enterica serovar enteritidis (s. enteritidis) obtained from humans and layer farms in belgium collected during 2000-2010. three periods were compared, namely (i) before implementation of vaccination (2000-2004), (ii) during voluntary vaccination (2005-2006) and (iii) during implementation of the national control program (ncp) for salmonella including mandatory vaccination against s. enteritidis (2007-2010). the characteristics compa ...201424268005
molecular epidemiological analysis of five outbreaks associated with salmonella enterica serovar enteritidis between 2008 and 2010 on jeju island, republic of korea.with the increasing incidence of salmonella enterica serovar enteritidis (se) infections, five se foodborne outbreaks were identified between 2008 and 2010 on jeju island, republic of korea. in this study, the genetic relatedness of isolates recovered from the five outbreaks was investigated to identify the source of foodborne se infections. in total, 57 se isolates from five outbreaks (17 isolates, 5 isolates, 18 isolates, 8 isolates, and 9 isolates, respectively) were used for antimicrobial su ...201424161024
enumeration of salmonellae in table eggs, pasteurized egg products, and egg-containing dishes by using quantitative real-time pcr.salmonellae are a major cause of food-borne outbreaks in europe, with eggs and egg products being identified as major sources. due to the low levels of salmonellae in eggs and egg products, direct quantification is difficult. in the present study, enrichment quantitative real-time pcr (qpcr) was employed for enumeration of salmonellae in different matrices: table eggs, pasteurized egg products, and egg-containing dishes. salmonella enterica serovar enteritidis and s. enterica serovar tennessee w ...201424362433
estimation of the rate of egg contamination from salmonella-infected chickens.salmonella enterica serovar enteritidis (s. enteritidis) is one of the most prevalent causes for human gastroenteritis and is by far the predominant salmonella serovar among human cases, followed by salmonella typhimurium. contaminated eggs produced by infected laying hens are thought to be the main source of human infection with s. enteritidis throughout the world. although previous studies have looked at the proportion of infected eggs from infected flocks, there is still uncertainty over the ...201423398774
prosthetic joint infection due to salmonella species: a case series.prosthetic joint infection (pji) due to salmonella is rare. numerous outbreaks of salmonella have been reported throughout the united states in the last decade. we reviewed and analyzed cases of salmonella pji seen at our institution.201425424009
immunoprotectivity of salmonella enterica serovar enteritidis virulence protein, invh, against salmonella typhi.typhoid fever is a dreadful disease of a major threat to public health in developing countries. vaccination with bacterial immunodominant components such as surface proteins may prove as a potent alternative to live attenuated vaccines. invh, an important part of needle complex in type three secretion system (ttss) plays important role in efficient bacterial adherence and entry into epithelial cells.201425422747
environmental salmonella in agricultural fair poultry exhibits in colorado.salmonella enterica is a common zoonotic pathogen in humans. transmission typically occurs through consumption of contaminated food products or contact with infected animals, including poultry or their environment. the objective of this study was to estimate the frequency of salmonella contamination in the environment in poultry exhibits at agricultural fairs. samples were collected from cages, feed, floors and tables in the exhibit and cultured for salmonella. at least one environmental sample ...201423773691
[antibiotic resistance and virulence factors in clinical salmonella enterica isolates].the increase of salmonella enterica isolates multi-resistant to different antibiotics, including β-lactams and fluoroquinolones, is a problem of clinical importance. the dissemination of salmonella typhimurium resistant to ampicillin (amp)-chloramphenicol (chl)-streptomycin (str)-sulphonamides and (sul)-tetracycline (tet), that harbour the salmonella genomic island type 1 (sgi1), and the acquisition of transferable genetic material have favoured the multi-resistance in this genus.201423618618
comparison of five molecular subtyping methods for differentiation of salmonella kentucky isolates in tunisia.salmonellosis is one of the most common causes of food-borne infection worldwide. in the last decade, salmonella enterica serovar kentucky has shown an increase in different parts of the world with the concurrent emergence of multidrug-resistant isolates. these drug-resistant types spread from africa and the middle east to europe and asia. although s. kentucky serovar is of potential human relevance, there is currently no standardized fingerprinting method for it, in tunisia. in the present stud ...201423839713
comparative molecular dynamics simulation studies for determining factors contributing to the thermostability of chemotaxis protein "chey".comparative molecular dynamics simulations of chemotaxis protein "chey" from thermophilic origin thermotoga maritima and its mesophilic counterpart salmonella enterica have been performed for 10 ns each at 300 and 350 k, and 20 ns each at 400 and 450 k. the trajectories were analyzed in terms of different factors like root-mean-square deviation, root-mean-square fluctuation, radius of gyration, solvent accessible surface area, h-bonds, salt bridge content, and protein-solvent interactions which ...201423796004
typing of salmonella enterica serovar infantis isolates from 51 outbreaks in germany between 1974 and 2009 by a novel phage-typing scheme.we developed a new phage-typing method and evaluated its application in combination with xbai macrorestriction analysis by pulsed-field gel electrophoresis (pfge) as a useful tool for the long-term epidemiology of salmonella enterica serovar infantis. in this study, we investigated 1008 s. infantis isolates recovered from humans, various animal species and food products from 1973 to 2009. the typing scheme is based on 17 typing phages, defining 61 different patterns within the strain collection. ...201423517655
prevalence and characterization of extended-spectrum β-lactamase-producing clinical salmonella enterica isolates in dakar, senegal, from 1999 to 2009.a total of 1623 clinical isolates of salmonella belonging to 229 serotypes were received by the senegalese reference center for enterobacteria from january 1999 to december 2009. the most common serotypes were enteritidis (19% of the isolates), typhi (8%), typhimurium (7%) and kentucky (4%). a significant increase in the prevalence of resistance to amoxicillin (0.9% in 1999 to 11.1% in 2009) and nalidixic acid (0.9% in 1999 to 26.7% in 2009) was observed in non-typhoidal salmonella serotypes. fo ...201423992040
structural characteristics of thermostable immunogenic outer membrane protein from salmonella enterica serovar typhi.in this work, we explored the acid-induced unfolding pathway of non-porin outer membrane protein (omp), an immunogenic protein from salmonella typhi, by monitoring the conformational changes over a ph range of 1.0-7.0 by circular dichroism, intrinsic fluorescence, ans binding, acrylamide quenching, and dynamic light scattering. the spectroscopic measurements showed that omp in its native state at ph 7.0 exists in more stable and compact conformation. in contrast, at ph 2.0, omp retains substanti ...201423949993
the annexin a2/p11 complex is required for efficient invasion of salmonella typhimurium in epithelial cells.the facultative intracellular pathogen, salmonella enterica, triggers its own uptake into non-phagocytic epithelial cells. invasion is dependent on a type 3 secretion system (t3ss), which delivers a cohort of effector proteins across the plasma membrane where they induce dynamic actin-driven ruffling of the membrane and ultimately, internalization of the bacteria into a modified phagosome. in eukaryotic cells, the calcium- and phospholipid-binding protein annexin a2 (anxa2) functions as a platfo ...201423931152
outbreak of salmonella enterica serotype i 4,5,12:i:- infections: the challenges of hypothesis generation and microwave cooking.we investigated an outbreak of 396 salmonella enterica serotype i 4,5,12:i:- infections to determine the source. after 7 weeks of extensive hypothesis-generation interviews, no refined hypothesis was formed. nevertheless, a case-control study was initiated. subsequently, an iterative hypothesis-generation approach used by a single interviewing team identified brand a not-ready-to-eat frozen pot pies as a likely vehicle. the case-control study, modified to assess this new hypothesis, along with p ...201423916064
diversity and antimicrobial susceptibility of salmonella enterica serovars isolated from pig farms in ibadan, nigeria.animals including food animals play a significant role in the epidemiology of salmonella enterica. the control requires identification of sources and institution of targeted interventions. this study investigates the diversity of s. enterica serovars, antimicrobial susceptibility, and occurrence of plasmid-mediated quinolone resistance (pmqr) genes in pigs in ibadan, nigeria. pooled fresh pen floor fecal samples of pigs collected from 31 pig farms were cultured; the salmonella isolates were sero ...201423893398
national outbreaks of salmonella infection in the uk, 2000-2011.over a 12-year period, the health protection agency's (now public health england's) department of gastrointestinal and emerging infections (gezi) investigated over 100 potential national outbreaks of salmonella enterica. these ranged from a cluster of cases requiring data interrogation and monitoring of the situation, to full blown case-control studies involving hundreds of interviews, many staff, multi-agency collaboration and the media. vehicles of infection ranged from the usual suspects of c ...201423721866
evaluation of pre-pcr processing approaches for enumeration of salmonella enterica in naturally contaminated animal feed.three pre-pcr processing strategies for the detection and/or quantification of salmonella in naturally contaminated soya bean meal were evaluated.201423998352
the salmonella enterica zint structure, zinc affinity and interaction with the high-affinity uptake protein znua provide insight into the management of periplasmic zinc.in gram-negative bacteria the znuabc transporter ensures adequate zinc import in zn(ii)-poor environments, like those encountered by pathogens within the infected host. recently, the metal-binding protein zint was suggested to operate as an accessory component of znuabc in periplasmic zinc recruitment. since zint is known to form a zint-znua complex in the presence of zn(ii) it was proposed to transfer zn(ii) to znua. the present work was undertaken to test this claim.201424128931
carbapenemase-producing enterobacteriaceae and non-enterobacteriaceae from animals and the environment: an emerging public health risk of our own making?acquired carbapenemases pose one of the most pressing public health threats relating to antibiotic resistance. in most countries, the number of carbapenemase-producing bacteria from human clinical specimens is rising, and the epidemiological status of these multiresistant bacteria is progressively worsening. furthermore, there is a growing number of reports of carbapenemases found either in bacteria isolated from non-human sources or in salmonella enterica subsp. enterica, a zoonotic species. ho ...201424092657
salmonella prostatitis in a man with spinal cord injury.prostatitis is a very unusual manifestation of salmonella urinary tract infection and has not been reported in men with spinal cord injury (sci).201424090046
treatment of infected abdominal aortic aneurysm caused by salmonella.we reviewed the outcomes of patients treated for nontyphoidal salmonella-infected abdominal aortic aneurysm (aaa) treatment at a single center.201424084275
development of a novel hexa-plex pcr method for identification and serotyping of salmonella species.salmonella is one of the most important foodborne pathogens, which causes a huge economic burden worldwide. to detect salmonella rapidly is very meaningful in preventing salmonellosis and decreasing economic losses. currently, isolation of salmonella is confirmed by biochemical and serobased serotyping methods, which are time consuming, labor intensive, and complicated. to solve this problem, a hexa-plex polymerase chain reaction (pcr) method was developed using comparative genomics analysis and ...201424066904
salmonella enterica flagellin is recognized via fls2 and activates pamp-triggered immunity in arabidopsis thaliana.infections with salmonella enterica belong to the most prominent causes of food poisoning and infected fruits and vegetables represent important vectors for salmonellosis. recent evidence indicates that plants recognize s. enterica and raise defense responses. nonetheless, the molecular mechanisms controlling the interaction of s. enterica with plants are still largely unclear. here, we show that flagellin from s. enterica represents a prominent pathogen-associated molecular pattern (pamp) in ar ...201424198231
serotype profile and molecular characterization of antimicrobial resistance in non-typhoidal salmonella isolated from gastroenteritis cases over nine years.resistance to third-generation cephalosporins in non-typhoidal salmonella (nts) is emerging worldwide. we report the occurrence of extended-spectrum beta-lactamase (esbl) phenotypes in 53.4 % of nts isolated over a period of nine years from gastroenteritis cases. esbl and ampc co-production was observed in 21 % of the isolates. occurrence of blactx-m-15 and blacmy-2 resistance genes was observed in 11.6 % and 37 % of the isolates respectively. overall, salmonella enterica serovar senftenberg was ...201424149623
evaluating gulls as potential vehicles of salmonella enterica serotype newport (jjpx01.0061) contamination of tomatoes grown on the eastern shore of virginia.salmonella enterica serovar newport pattern jjpx01.0061 has been identified as causing several multistate outbreaks in the last 10 years, primarily due to contamination of tomatoes grown in virginia. the goal of this study was to evaluate gulls as a potential vehicle of s. newport pattern 61 contamination for tomatoes grown on the eastern shore of virginia. gull fecal samples were collected at four sites in eastern virginia for 3 months (may to july) in 2012, resulting in 360 samples, among whic ...201424141129
molecular study of quinolone resistance mechanisms and clonal relationship of salmonella enterica clinical isolates.in the last few years, the number of salmonella enterica strains resistant to nalidixic acid has steadily increased. in a previous study, the quinolone susceptibility phenotype and genotype of 38 s. enterica clinical isolates (19 s. enterica serovar typhimurium and 19 s. enterica serovar enteritidis) were determined. forty-two percent of the isolates showed nalidixic acid resistance associated with a mutation in gyra together with putative overexpression of efflux pump(s). in this study, mutatio ...201424139882
oral vaccination with inhibin dna delivered using attenuated salmonella choleraesuis for improving reproductive traits in mice.the objective of this study was to examine the efficacy and safety of a novel inhibin vaccine containing inhibin α (1-32) fragments in mice. a recombinant plasmid pvax-asd-is was constructed by inserting recombinant inhibin α (1-32) and the hepatitis b surface antigen s into the plasmid in which the asd gene, rather than the kanamycin gene, was a selection marker. ninety kuming mice were divided into six groups consisting of 15 mice each. first group was (c1) injected with 200 µl of pbs, second ...201424123188
dissecting cobamide diversity through structural and functional analyses of the base-activating cobt enzyme of salmonella enterica.cobamide diversity arises from the nature of the nucleotide base. nicotinate mononucleotide (namn):base phosphoribosyltransferases (cobt) synthesize α-linked riboside monophosphates from diverse nucleotide base substrates (e.g., benzimidazoles, purines, phenolics) that are incorporated into cobamides.201424121107
clonal spread of salmonella enterica serovar infantis in serbia: acquisition of mutations in the topoisomerase genes gyra and parc leads to increased resistance to fluoroquinolones.quinolone-resistant salmonella infantis (n = 64) isolated from human stool samples, food and poultry during the years 2006-2011 were analysed for their resistance phenotypes, macrorestriction patterns and molecular mechanisms of decreased susceptibility to fluoroquinolones. minimum inhibitory concentrations (mics) of nalidixic acid (nal) and ciprofloxacin (cip) were determined by the agar dilution procedure, and the susceptibility to additional antimicrobial agents was determined by the disc dif ...201424119387
siia and siib are novel type i secretion system subunits controlling spi4-mediated adhesion of salmonella enterica.the giant non-fimbrial adhesin siie is essential to establish intimate contact between salmonella enterica and the apical surface of polarized epithelial cells. siie is secreted by a type i secretion system (t1ss) encoded by salmonella pathogenicity island 4 (spi4). we identified siia and siib as two regulatory proteins encoded by spi4. mutant strains in siia or siib still secrete siie, but are highly reduced in adhesion to, and invasion of polarized cells. siia and siib are inner membrane prote ...201424119191
postharvest transfer and survival of salmonella enterica serotype enteritidis on living lettuce.the potential for postharvest transfer of salmonella to 'living lettuce' is not well understood. in this study, the transfer of salmonella enterica enteritidis (6 log cfu g(-1) ) from worker hands or contaminated roots to leaves of living lettuce was quantified. transfer rates of salmonella from contaminated gloves to sequentially handled lettuce heads ranged from 94% to head 1, 82% to head 2 and 69% to head 3. on average, 2.9 ± 0.1 log cfu g(-1) (64%) salmonella was transferred from inoculated ...201424117925
molecular characterization of salmonella enterica serovar 4,[5],12:i:- dt193 assut strains from two outbreaks in italy.salmonella enterica subsp. enterica serovar 4,[5],12:i:- dt193 is recognized as an emerging monophasic variant of salmonella typhimurium in many european countries. resistance to ampicillin, streptomycin, sulphonamides, and tetracycline (r-type assut) is described as one of the most common profiles of resistance within this clone. recently, strains presenting such features were isolated from two unrelated outbreaks in italy. strains were characterized by pulsed-field gel electrophoresis (pfge), ...201424328499
a unique megaplasmid contributes to stress tolerance and pathogenicity of an emergent salmonella enterica serovar infantis strain.of all known salmonella enterica serovars, s. infantis is one of the most commonly isolated and has been recently emerging worldwide. to understand the recent emergence of s. infantis in israel, we performed extensive comparative analyses between pre-emergent and the clonal emergent s. infantis populations. we demonstrate the fixation of adaptive mutations in the dna gyrase (gyra) and nitroreductase (nfsa) genes, conferring resistance to quinolones and nitrofurans, respectively, and the carriage ...201424320043
salmonella enterica isolated from infections in australian livestock remain susceptible to critical antimicrobials.salmonella enterica is a zoonotic pathogen causing a variety of diseases in humans and animals. many countries are reporting an increase in the prevalence of multidrug-resistant (mdr) s. enterica in food animals. the aim of this study was to determine whether s. enterica isolated from livestock in new south wales, australia, have similar resistance traits to those reported internationally. salmonella enterica (n=165) from clinical infections in food animals between 2007 and 2011 were serotyped a ...201424314826
transcriptional profile of salmonella enterica subsp. enterica serovar weltevreden during alfalfa sprout colonization.sprouted seeds represent a great risk for infection by human enteric pathogens because of favourable growth conditions for pathogens during their germination. the aim of this study was to identify mechanisms of interactions of salmonella enterica subsp. enterica weltevreden with alfalfa sprouts. rna-seq analysis of s. weltevreden grown with sprouts in comparison with m9-glucose medium showed that among a total of 4158 annotated coding sequences, 177 genes (4.3%) and 345 genes (8.3%) were transcr ...201424308841
typhoid epidemiology, diagnostics and the human challenge model.infection caused by ingestion of human-restricted salmonella enterica serovars typhi and paratyphi predominantly affects the most impoverished sections of society. in this review, we describe recent advances made in estimating the burden of illness and the important role improved diagnostic tests may have in controlling infection and report the development of a new human challenge model of typhoid infection.201424304980
comparison of two sampling and culture systems for detection of salmonella enterica in the environment of a large animal hospital.nosocomial salmonellosis is an important problem in veterinary hospitals that treat horses and other large animals. detection and mitigation of outbreaks and prevention of healthcare-associated infections often require detection of salmonella enterica in the hospital environment.201424303999
inhibition of escherichia coli o157:h7 and salmonella enterica on spinach and identification of antimicrobial substances produced by a commercial lactic acid bacteria food safety intervention.the microbiological safety of fresh produce is of concern for the u.s. food supply. members of the lactic acid bacteria (lab) have been reported to antagonize pathogens by competing for nutrients and by secretion of substances with antimicrobial activity, including organic acids, peroxides, and antimicrobial polypeptides. the objectives of this research were to: (i) determine the capacity of a commercial lab food antimicrobial to inhibit escherichia coli o157:h7 and salmonella enterica on spinac ...201424290643
use of β-cyclodextrin and activated carbon for quantification of salmonella enterica ser. enteritidis from ground beef by conventional pcr without enrichment.the high level of pcr inhibitors present in ground beef is a major factor that affects molecular based techniques, such as the polymerase chain reaction (pcr), for the detection of salmonella enterica. in this study, the use of β-cyclodextrin and milk protein coated activated carbon (mp-cac) allowed the pcr to detect low numbers of salmonella seeded into ground beef without enrichment of samples. inva was used as target gene in the conventional pcr protocol. with 25 g samples of ground beef cont ...201424290629
resistance to third-generation cephalosporins in human non-typhoidal salmonella enterica isolates from england and wales, 2010-12.to identify the mechanism(s) underlying cefotaxime resistance in 118 of 21,641 (0.55%) non-typhoidal salmonella enterica isolates collected from humans throughout england and wales from january 2010 to september 2012.201424288030
altered ifn-γ-mediated immunity and transcriptional expression patterns in n-ethyl-n-nitrosourea-induced stat4 mutants confer susceptibility to acute typhoid-like disease.salmonella enterica is a ubiquitous gram-negative intracellular bacterium that continues to pose a global challenge to human health. the etiology of salmonella pathogenesis is complex and controlled by pathogen, environmental, and host genetic factors. in fact, patients immunodeficient in genes in the il-12, il-23/ifn-γ pathway are predisposed to invasive nontyphoidal salmonella infection. using a forward genomics approach by n-ethyl-n-nitrosourea (enu) germline mutagenesis in mice, we identifie ...201424285835
isolation and molecular characterization of salmonella enterica, escherichia coli o157:h7 and shigella spp. from meat and dairy products in egypt.foodborne pathogens are a major threat to food safety, especially in developing countries where hygiene and sanitation facilities are often poor. salmonella enterica, escherichia coli o157:h7 and shigella spp. are among the major causes of outbreaks of foodborne diseases. this large-scale study investigated the prevalence of these foodborne pathogens in meat (beef and chicken) and dairy products collected from street vendors, butchers, retail markets and slaughterhouses in egypt. a total of 1600 ...201424239976
role of salmonella typhimurium small rnas ryhb-1 and ryhb-2 in the oxidative stress response.as part of the response to specific stress conditions, bacteria express small molecules of non-coding rna which maintain cellular homeostasis by regulating gene expression, commonly at the post-transcriptional level. among these, in salmonella enterica sv. typhimurium, the paralog small non-coding rnas ryhb-1 and ryhb-2 play an important role in iron homeostasis. in addition, in the present work, we show that ryhb-1 and ryhb-2 also participate in the response to hydrogen peroxide (h2o2). deletio ...201424239962
clinically relevant multidrug resistant salmonella enterica in swine and meat handlers at the abattoir.the presence of multidrug resistant (mdr) salmonella serotypes in slaughtered swine, carcasses, meat and meat handlers is scarcely evaluated. recently we demonstrated that diverse salmonella serotypes are frequently present in swine, pork meat and carcasses, and meat handlers at portuguese abattoirs. here we have characterized their antibiotic resistance phenotypes and genotypes, helping elucidate the flow of mdr salmonella in the food chain. testing 60 salmonella isolates from different serotyp ...201424239169
proteomics-based identification of plasma proteins and their association with the host-pathogen interaction in chronic typhoid carriers.current diagnostic tests are inadequate to detect typhoid cases, as well as the chronic carrier state, the sole reservoir of salmonella enterica serovar typhi. the current study was conducted to find new molecular signatures of pathogen/disease to understand the mechanism behind the host-pathogen interaction in enteric fever.201424291468
serovars, bacteriophage types and antimicrobial sensitivities associated with salmonellosis in dogs in the uk (1954-2012).serovars and bacteriophage (phage) types were determined for 442 isolates of salmonella enterica from dogs in the uk submitted to the scottish salmonella reference laboratory from 1954 to 2012. the most frequent serovars were salmonella typhimurium (196 isolates; 44.3 per cent), dublin (40 isolates; 9.0 per cent), enteritidis (28 isolates; 6.3 per cent), montevideo (19 isolates; 4.3 per cent), virchow (10 isolates; 2.3 per cent), heidelberg (8 isolates; 1.8 per cent) and derby (8 isolates; 1.8 p ...201424277916
prevalence and fimbrial genotype distribution of poultry salmonella isolates in china (2006 to 2012).in this study, a total of 323 salmonella enterica strains were isolated from 3,566 rectal swab samples of 51 poultry farms in seven regions of 12 provinces of china between 2006 and 2012. the prevalences of salmonella sp. carriage were 12.4% in geese (66 positive/533 samples), 10.4% in turkeys (32/309), 9.8% in chickens (167/1,706), 6.8% in ducks (41/601), and 4.1% in pigeons (17/417), respectively. these isolates belonged to 20 serovars, in which the most frequent serovars were s. enterica sero ...201424242234
recombination and annealing pathways compete for substrates in making rrn duplications in salmonella enterica.tandem genetic duplications arise frequently between the seven directly repeated 5.5-kb rrn loci that encode ribosomal rnas in salmonella enterica. the closest rrn genes, rrnb and rrne, flank a 40-kb region that includes the purhd operon. duplications of purhd arise by exchanges between rrn loci and form at a high rate (10(-3)/cell/division) that remains high in strains blocked for early steps in recombination (reca, recb, and/or recf), but drops 30-fold in mutants blocked for later holliday jun ...201424214339
evaluation of whole genome sequencing for outbreak detection of salmonella enterica.salmonella enterica is a common cause of minor and large food borne outbreaks. to achieve successful and nearly 'real-time' monitoring and identification of outbreaks, reliable sub-typing is essential. whole genome sequencing (wgs) shows great promises for using as a routine epidemiological typing tool. here we evaluate wgs for typing of s. typhimurium including different approaches for analyzing and comparing the data. a collection of 34 s. typhimurium isolates was sequenced. this consisted of ...201424505344
variations in motility and biofilm formation of salmonella enterica serovar typhi.salmonella enterica serovar typhi (s. typhi) exhibits unique characteristics as an intracellular human pathogen. it causes both acute and chronic infection with various disease manifestations in the human host only. the principal factors underlying the unique lifestyle of motility and biofilm forming ability of s. typhi remain largely unknown. the main objective of this study was to explore and investigate the motility and biofilm forming behaviour among s. typhi strains of diverse background.201424499680
dietary supplementation with soluble plantain non-starch polysaccharides inhibits intestinal invasion of salmonella typhimurium in the chicken.soluble fibres (non-starch polysaccharides, nsp) from edible plants but particularly plantain banana (musa spp.), have been shown in vitro and ex vivo to prevent various enteric pathogens from adhering to, or translocating across, the human intestinal epithelium, a property that we have termed contrabiotic. here we report that dietary plantain fibre prevents invasion of the chicken intestinal mucosa by salmonella. in vivo experiments were performed with chicks fed from hatch on a pellet diet con ...201424498347
bacterial population structure and dynamics during the development of almond drupes.to describe the bacterial populations and their dynamics during the development of almond drupes.201424494712
a low gastric ph mouse model to evaluate live attenuated bacterial vaccines.the low ph of the stomach serves as a barrier to ingested microbes and must be overcome or bypassed when delivering live bacteria for vaccine or probiotic applications. typically, the impact of stomach acidity on bacterial survival is evaluated in vitro, as there are no small animal models to evaluate these effects in vivo. to better understand the effect of this low ph barrier to live attenuated salmonella vaccines, which are often very sensitive to low ph, we investigated the value of the hist ...201424489912
in-feed use of heavy metal micronutrients in u.s. swine production systems and its role in persistence of multidrug-resistant salmonellae.the study aimed to characterize the role of heavy metal micronutrients in swine feed in emergence of heavy-metal-tolerant and multidrug-resistant salmonella organisms. we conducted a longitudinal study in 36 swine barns over a 2-year period. the feed and fecal levels of cu(2+) and zn(2+) were measured. salmonella was isolated at early and late finishing. mics of copper sulfate and zinc chloride were measured using agar dilution. antimicrobial susceptibility was tested using the kirby-bauer metho ...201424487542
evaluation of efficacy, biodistribution and safety of antibiotic-free plasmid encoding somatostatin genes delivered by attenuated salmonella enterica serovar choleraesuis.we describe here a balanced-lethal system using an asd(+) expression plasmid pvgs/2ss-asd encoding two copies of somatostatin (ss) genes carried by δasd/δcrp double mutant salmonella enterica serovar choleraesuis (named c501). the advantage of this novel system is the use of asd (aspartate-semialdehyde dehydrogenase) gene as selection marker to replace the antibiotic resistance markers, thus eliminating the industrial cultivation and environmental problems. we then evaluated the efficacy, biodis ...201424486312
one health and food-borne disease: salmonella transmission between humans, animals, and plants.there are >2,600 recognized serovars of salmonella enterica. many of these salmonella serovars have a broad host range and can infect a wide variety of animals, including mammals, birds, reptiles, amphibians, fish, and insects. in addition, salmonella can grow in plants and can survive in protozoa, soil, and water. hence, broad-host-range salmonella can be transmitted via feces from wild animals, farm animals, and pets or by consumption of a wide variety of common foods: poultry, beef, pork, egg ...201426082128
lack of efflux mediated quinolone resistance in salmonella enterica serovars typhi and paratyphi a.salmonella enterica serovars typhi and paratyphi a isolates from human patients in france displaying different levels of resistance to quinolones or fluoroquinolones were studied for resistance mechanisms to these antimicrobial agents. all resistant isolates carried either single or multiple target gene mutations (i.e., in gyra, gyrb, or parc) correlating with the resistance levels observed. active efflux, through upregulation of multipartite efflux systems, has also been previously reported as ...201424478769
a gene knock-in method used to purify plasmid pspi12 from salmonella enterica serovar pullorum and characterization of ipaj.a small plasmid with 4080 bp long, designated pspi12, was purified from salmonella enterica serovar pullorum using a gene knock-in method by inserting a kanamycin resistance cassette in the plasmid. the g+c content of the plasmid was 51.8%, which is in the range of salmonella genomic dna. a sequence analysis revealed that pspi12 had 99.1% homology to psfd10, which was first reported in the vaccine strain s. enterica serovar chloreaesuis c500, but not prevalent among other strains of s. chloreaes ...201424468333
different efficiency of ozonated water washing to inactivate salmonella enterica typhimurium on green onions, grape tomatoes, and green leaf lettuces.ozonated water washing is one of the emerging techniques to inactivate foodborne pathogens on produce, and limited information is available to optimize processing parameters (treatment time, temperature, and ph) to improve ozone efficacy on salmonella inactivation for different produce. the efficacy of ozonated water washing for inactivation of salmonella enterica typhimurium on green onions, grape tomatoes and green leaf lettuces were studied in our research. surface inoculated fresh produce we ...201424467482
biofilm formation by salmonella enterica serovar 1,4,[5],12:i:- portuguese isolates: a phenotypic, genotypic, and socio-geographic analysis.biofilm-forming ability is well established as an important virulence factor. however, there are no studies available regarding biofilm formation of salmonella typhimurium 1,4,[5],12:i:-, the new pandemic serovar in europe. to address this problem, biofilm expression by salmonella 1,4,[5],12:i:- was evaluated using 133 isolates from clinical, environmental and animal origins, collected in portugal from 2006 to 2011. biofilm detection was performed by phenotypic and genotypic methods, such growth ...201424463530
salmonella isolated from individual reptiles and environmental samples from terraria in private households in sweden.this study investigates salmonella spp. isolated from privately kept reptiles and from environmental samples such as bedding materials or water from the floor of the enclosures (terraria). it also compares isolation of salmonella using modified semisolid rappaport-vassiliadis (msrv) medium or selective enrichment in rappaport-vassiliadis-soya (rvs) pepton broth. cloacal swabs or swabs from the cloacal area were collected from 63 individual reptiles belonging to 14 households. all reptiles were f ...201424461167
complete genome sequence of salmonella enterica serovar agona pulsed-field type sagoxb.0066, cause of a 2008 pan-european outbreak.salmonella enterica serovar agona is in the top 10 most common nontyphoidal serovars reported in humans in the european union. here we report the complete genome sequence of an s. enterica serovar agona isolate, designated 24249, that was the cause of a pan-european outbreak in 2008 with 163 confirmed cases reported.201424459278
whole-genome sequencing of salmonella enterica subsp. enterica serovar cubana strains isolated from agricultural sources.we report the draft genomes of salmonella enterica subsp. enterica serovar cubana strain cvm42234, isolated from chick feed in 2012, and s. cubana strain 76814, isolated from swine in 2004. the genome sizes are 4,975,046 and 4,936,251 bp, respectively.201424459266
a flagellin-derived toll-like receptor 5 agonist stimulates cytotoxic lymphocyte-mediated tumor immunity.toll-like receptor (tlr) mediated recognition of pathogen associated molecular patterns allows the immune system to rapidly respond to a pathogenic insult. the "danger context" elicited by tlr agonists allows an initially non-immunogenic antigen to become immunogenic. this ability to alter environment is highly relevant in tumor immunity, since it is inherently difficult for the immune system to recognize host-derived tumors as immunogenic. however, immune cells may have encountered certain tlr ...201424454895
antimicrobial resistance in salmonella strains clinically isolated in hyogo, japan (2009-2012).the purpose of this study was to examine the in vitro susceptibilities to antimicrobial agents and genetic diversity of 195 clinical strains of salmonella spp., which were isolated and examined for the extended-spectrum β-lactamase (esbl) blactx-m gene and the presence of gyra, gyrb, parc, and pare genes mutations in hyogo, japan, from 2009 to 2012. forty-three of the 195 strains were antimicrobial resistant. two salmonella enterica subsp. enterica strains, 1 serovar schwarzengrund, and 1 serova ...201424451104
antimicrobial beeswax coated polylactide films with silver control release capacity.although the application of silver based antimicrobial systems is a widespread technology, its implementation in areas such as food packaging is still challenging. the present paper describes the fabrication of poly(lactic acid) (pla) coated with beeswax with controlled release properties for sustained antimicrobial performance. release of silver ions from the polymers was monitored voltammetrically under various conditions (surface contact, immersion in various liquid media and at different ph ...201424448276
salmonella vaccines: lessons from the mouse model or bad teaching?salmonella enterica subsp. enterica includes several very important human serovars including typhi, paratyphi, typhimurium and enteritidis. these bacteria cause a significant global burden of disease, typically classified into enteric fever, gastroenteritis and, more recently, invasive non-typhoidal salmonellosis (ints). vaccines have been developed for one of these serovars, s. typhi and the recent increase in ints cases has resulted in a push to develop new vaccines that will inhibit disease b ...201424440968
ompr phosphorylation regulates omps1 expression by differentially controlling the use of promoters.the salmonella enterica omps1 gene encodes a quiescent porin that belongs to the ompc/ompf family. in the present work we analysed the regulatory effects of ompr phosphorylation on omps1 expression. we found that in vivo, ompr in its phosphorylated form (ompr-p) was important in the regulation of the two omps1 promoters: ompr-p activated the p1 promoter and repressed the p2 promoter in an envz-dependent manner; expression occurs from the p2 promoter in an ompr mutant. in vitro, ompr-p had a high ...201424440835
crystal structures of type i dehydroquinate dehydratase in complex with quinate and shikimate suggest a novel mechanism of schiff base formation.a component of the shikimate biosynthetic pathway, dehydroquinate dehydratase (dhqd) catalyzes the dehydration of 3-dehydroquniate (dhq) to 3-dehydroshikimate. in the type i dhqd reaction mechanism a lysine forms a schiff base intermediate with dhq. the schiff base acts as an electron sink to facilitate the catalytic dehydration. to address the mechanism of schiff base formation, we determined structures of the salmonella enterica wild-type dhqd in complex with the substrate analogue quinate and ...201424437575
the zupt transporter plays an important role in zinc homeostasis and contributes to salmonella enterica virulence.zinc is an essential metal for cellular homeostasis and function in both eukaryotes and prokaryotes. to acquire this essential nutrient, bacteria employ transporters characterized by different affinity for the metal. several studies have investigated the role of the high affinity transporter znuabc in the bacterial response to zinc shortage, showing that this transporter has a key role in adapting bacteria to zinc starvation. in contrast, the role of the low affinity zinc importer zupt has been ...201424430377
live oral salmonella enterica serovar typhi vaccines ty21a and cvd 909 induce opsonophagocytic functional antibodies in humans that cross-react with s. paratyphi a and s. paratyphi b.live oral salmonella enterica serovar typhi vaccine ty21a induces specific antibodies that cross-react against salmonella enterica serovar paratyphi a and salmonella enterica serovar paratyphi b, although their functional role in clearance remains unknown. we utilized an in vitro assay with thp-1 macrophages to compare the phagocytosis and survival of salmonella opsonized with heat-inactivated human sera obtained before and after vaccination with ty21a or a live oral s. typhi vaccine, cvd 909. o ...201424429069
how the structure of the large subunit controls function in an oxygen-tolerant [nife]-hydrogenase.salmonella enterica is an opportunistic pathogen that produces a [nife]-hydrogenase under aerobic conditions. in the present study, genetic engineering approaches were used to facilitate isolation of this enzyme, termed hyd-5. the crystal structure was determined to a resolution of 3.2 å and the hydro-genase was observed to comprise associated large and small subunits. the structure indicated that his229 from the large subunit was close to the proximal [4fe-3s] cluster in the small subunit. in a ...201424428762
control of salmonella enteritidis in turkeys using organic acids and competitive exclusion product.to evaluate the use of organic acids (oas) and competitive exclusion (ce) product administered continuously in the feed and transiently in drinking water on the control of salmonella enterica subspecie enterica serotype enteritidis (se) prior to slaughter.201424797347
demonstration of persistent contamination of a cooked egg product production facility with salmonella enterica serovar tennessee and characterization of the persistent strain.the aim of this study was to investigate whether continuous contamination of light pasteurized egg products with salmonella enterica serovar tennessee (s. tennessee) at a large european producer of industrial egg products was caused by persistent contamination of the production facility and to characterize the persistent strains.201424797223
efficacy and safety of an oral somatostatin dna vaccine without antibiotic resistance gene in promoting growth of piglets.this study aimed to evaluate the efficacy and safety of an oral dna vaccine against somatostatin (ss) (pgs/2ss-asd, encoding two copies of somatostatin genes) mediated by attenuated salmonella choleraesuis c500 without antibiotic resistance gene on piglets growth. a total of 50 piglets were uniformly divided into five groups. the animals in the first three groups were orally given vaccine in dose of either 5 9 1010, 5 9 109 or 5 9 108 colony-forming units (cfu).the remaining two groups were oral ...201424795986
preparation and properties of poly(vinyl alcohol)/chitosan blend bionanocomposites reinforced with cellulose nanocrystals/zno-ag multifunctional nanosized filler.a series of novel bionanocomposites were cast using different contents of zinc oxide-silver nanoparticles (zno-agnps) stabilized by cellulose nanocrystals (cnc) as multifunctional nanosized fillers in poly(vinyl alcohol)/chitosan (pva/cs) matrices. the morphological structure, mechanical properties, ultraviolet-visible absorption, and antimicrobial properties of the prepared films were investigated as a function of their cnc/zno-agnp content and compared with pva/chitosan/cnc bionanocomposite fi ...201424790433
multiple-locus variable number of tandem repeats analysis of salmonella enterica serotype paratyphi a from yuxi and comparison with isolates from the chinese medical culture collection center.the aim of the present study was to genotype salmonella enterica serotype paratyphi a (spa) isolated from yuxi, china, in a multiple-locus variable number of tandem repeats (vntrs) analysis (mlva) and to compare them with isolates from the chinese medical culture collection center (cmcc). potential vntrs were screened from the genomes of atcc9150 and aku_12601 using the tandem repeats finder program. nine vntrs were established for mlva typing of 195 spa isolates from yuxi and 20 isolates from c ...201424788795
vespa tropica venom suppresses lipopolysaccharide-mediated secretion of pro-inflammatory cyto-chemokines by abrogating nuclear factor-κ b activation in microglia.the present study was aimed to evaluate the anti-inflammatory potentials of vespa tropica (vt) venom and its isolated peptides. effects of whole venom and its two peptides (vt1512 and vt1386) on lipopolysaccharide (lps) challenged bv-2 murine microglial cells was evaluated.201424781802
unusually long-lived pause required for regulation of a rho-dependent transcription terminator.up to half of all transcription termination events in bacteria rely on the rna-dependent helicase rho. however, the nucleic acid sequences that promote rho-dependent termination remain poorly characterized. defining the molecular determinants that confer rho-dependent termination is especially important for understanding how such terminators can be regulated in response to specific signals. here, we identify an extraordinarily long-lived pause at the site where rho terminates transcription in th ...201424778260
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