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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 ...201223209414
infection cycle of salmonella enterica serovar enteritidis in latent carrier mice.this work reports the distribution of an oral dose of salmonella enterica serovar enteritidis (se) in c57bl/6-bcgr mice, to study its pathogenesis in a latent carrier animal. mice orally inoculated with a high dose of se developed a latent infection characterized by the absence of clinical symptoms in which the cecum is functioning as a "strategic site" of se proliferation, releasing bacteria into feces intermittently over the 4-week study. a sequence of disruptions occurred in the small intesti ...201223210996
salmonella and campylobacter baseline in retail ground beef and whole-muscle cuts purchased during 2010 in the united states.salmonella enterica and campylobacter spp. cause a considerable number of human illnesses each year, and the vast majority of cases are foodborne. the purpose of this study was to establish the baseline of salmonella and campylobacter in beef products purchased from u.s. retail markets. sampling was carried out in 38 american cities. retail raw ground and whole-muscle beef (n = 2,885) samples were purchased and examined for the presence of salmonella. samples testing positive for salmonella were ...201223212006
modeling to predict growth/no growth boundaries and kinetic behavior of salmonella on cutting board surfaces.this study developed models to predict the growth probabilities and kinetic behavior of salmonella enterica strains on cutting boards. polyethylene coupons (3 by 5 cm) were rubbed with pork belly, and pork purge was then sprayed on the coupon surface, followed by inoculation of a five-strain salmonella mixture onto the surface of the coupons. these coupons were stored at 13 to 35°c for 12 h, and total bacterial and salmonella cell counts were enumerated on tryptic soy agar and xylose lysine deox ...201223212007
detection of escherichia coli o157:h7 and salmonella enterica in air and droplets at three u.s. commercial beef processing plants.bacteria are known to be present in the air at beef processing plants, but published data regarding the prevalences of airborne escherichia coli o157:h7 and salmonella enterica are very limited. to determine if airborne pathogens were present in beef processing facilities, we placed sedimentation sponges at various locations in three commercial beef plants that processed cattle from slaughter through fabrication. for the 291 slaughter area air samples, e. coli o157:h7 was isolated from 15.8% and ...201223212019
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 ...201223213248
[real-time pcr detection and quantification of emerging waterborne pathogens (ewps) and antibiotic resistance genes (args) in the downstream area of jiulong river].the emerging waterborne pathogens (ewps) and antibiotic resistance genes (args) are important for drinking water safety. the detection and quantification of 7 ewps and 4 args were carried out in jiulong river, which is the main water source of southwestern fujian province. the water samples were collected from four sites of the jiulong river downstream area and a drinking water treatment plant nearby. dna was extracted and quantified by real-time (sybr green) pcr methods after the samples were f ...201223213891
a fresh view of the cell biology of copper in enterobacteria.copper ions are essential but also very toxic. copper resistance in bacteria is based on export of the toxic ion, oxidation from cu(i) to cu(ii), and sequestration by copper-binding metal chaperones, which deliver copper ions to efflux systems or metal-binding sites of copper-requiring proteins. in their publication in this issue, osman et al. (2013) demonstrate how tightly copper resistance, homeostasis and delivery pathways are interwoven in salmonella enterica sv. typhimurium. copper is trans ...201323217080
lack of evidence of spill-over of salmonella enterica between cattle and sympatric iberian ibex (capra pyrenaica) from a protected area in catalonia, ne spain.salmonella enterica is a zoonotic agent of worldwide importance found in a wide range of wild hosts. however, its prevalence in many popular game species has never been assessed. iberian ibex (capra pyrenaica) is the main game caprinae of the iberian peninsula and around two thousand individuals are hunted every year for trophy or for home consumption. in this work, 313 iberian ibexes from the ports de tortosa i beseit national game reserve (ne spain) were tested for salmonella enterica in faece ...201423217161
pleural empyema due to salmonella typhi.salmonella serotypes most often produce gastroenteritis, enteric fever, bacteremia, vascular infection and chronic carrier state. localized infection may occur at any site after salmonella bacteremia. pulmonary involvement due to salmonella infection is rare. empyema occurs usually in elderly patients or in patients with underlying diseases such as diabetes mellitus, malignancy, or pulmonary disease. we report the case of an 83-year-old male diabetic patient who presented with fever, productive ...201223217492
interactions of salmonella enterica with dendritic cells.dendritic cells (dcs) form an important link between innate and adaptive immunity. however, dcs are also deployed as vehicles for systemic spread of pathogens. salmonella is an important gastrointestinal pathogen causing diseases ranging from gastroenteritis to typhoid fever. dcs play an important role in the immunity against salmonella infection, but this pathogen has also evolved efficient mechanisms to persist after phagocytosis by dcs, to spread using dcs as vehicles and to interfere with th ...201223221476
neurologic manifestations associated with an outbreak of typhoid fever, malawi--mozambique, 2009: an epidemiologic investigation.the bacterium salmonella enterica serovar typhi causes typhoid fever, which is typically associated with fever and abdominal pain. an outbreak of typhoid fever in malawi-mozambique in 2009 was notable for a high proportion of neurologic illness.201223226492
effects of natural mutations in the ramra locus on invasiveness of epidemic fluoroquinolone-resistant salmonella enterica serovar typhimurium isolates.fluoroquinolone (fq) resistance is increasing worldwide among salmonella species. among the mechanisms involved, increased efflux via the tripartite acrab-tolc efflux system is mainly modulated through control of expression via the ramra regulatory locus gene products. interestingly, in some reference strains these have also been experimentally shown to regulate cell invasion-related genes of the type iii secretion system 1 (t3ss-1). in this study, we investigated whether natural mutations occur ...201323230062
exposure of salmonella enterica serovar typhimurium to a protective monoclonal iga triggers exopolysaccharide production via a diguanylate cyclase-dependent pathway.sal4 is a monoclonal polymeric iga antibody directed against the o antigen (o-ag) of salmonella enterica serovar typhimurium (s. typhimurium), which is sufficient to protect mice against intestinal infections from s. typhimurium. we recently reported that the exposure of s. typhimurium to sal4 results in the immediate loss of flagellum-based motility, in alterations to the outer membrane (om) integrity, and in the concomitant appearance of a mucoid phenotype that is reminiscent of cells in the e ...201323230292
ensuring safety of home-produced eggs to control salmonellosis in poland: lessons from an outbreak in september 2011.implementation of control measures in line with european commission regulations has led to a decrease in salmonellosis in the european union since 2004. however, control programmes do not address laying hens whose eggs are produced for personal consumption or local sale. this article reports an investigatxion of a salmonellosis outbreak linked to home-produced eggs following a family event held in a farm in september 2011 near warsaw, poland. in the outbreak, 34 people developed gastroenteritis ...201223231857
molecular identification in monophasic and nonmotile variants of salmonella enterica serovar typhimurium.variant strains of salmonella enterica serovar typhimurium, lacking one or both flagellar phases have been widely reported. the monophasic s.1,4,[5],12:i:- variant has emerged worldwide in the past few years and has become one of the most frequently encountered in many countries. in contrast, monophasic s.1,4,[5],12:-:1,2 and nonmotile s.1,4,[5],12:-:- strains are rarely described. this study investigated seven molecular markers to identify and delineate monophasic s.1,4,[5],12:i:- (n = 90), s.1 ...201223233427
genome sequencing and analysis of salmonella enterica serovar typhi strain cr0063 representing a carrier individual during an outbreak of typhoid fever in kelantan, malaysia.salmonella typhi is a human restricted pathogen with a significant number of individuals as asymptomatic carriers of the bacterium. salmonella infection can be effectively controlled if a reliable method for identification of these carriers is developed. in this context, the availability of whole genomes of carrier strains through high- throughput sequencing and further downstream analysis by comparative genomics approaches is very promising. herein we describe the genome sequence of a salmonell ...201223234298
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 ...201323235264
attenuated salmonella typhimurium lacking the pathogenicity island-2 type 3 secretion system grow to high bacterial numbers inside phagocytes in mice.intracellular replication within specialized vacuoles and cell-to-cell spread in the tissue are essential for the virulence of salmonella enterica. by observing infection dynamics at the single-cell level in vivo, we have discovered that the salmonella pathogenicity island 2 (spi-2) type 3 secretory system (t3ss) is dispensable for growth to high intracellular densities. this challenges the concept that intracellular replication absolutely requires proteins delivered by spi-2 t3ss, which has bee ...201223236281
bifidobacterium infantis 35624 protects against salmonella-induced reductions in digestive enzyme activity in mice by attenuation of the host inflammatory response.salmonella-induced damage to the small intestine may decrease the villi-associated enzyme activity, causing malabsorption of nutrients and diarrhea, and thus contribute to the symptoms of infection. the objective of this study was to determine the mechanism by which different doses and durations of salmonella infection and lipopolysaccharide (lps) affect brush border enzyme activity in the mouse, and to determine if the probiotic bifidobacterium longum subspecies infantis 35624 could attenuate t ...201223238232
a novel target of iscs in escherichia coli: participating in dna phosphorothioation.many bacterial species modify their dna with the addition of sulfur to phosphate groups, a modification known as dna phosphorothioation. dnda is known to act as a cysteine desulfurase, catalyzing a key biochemical step in phosphorothioation. however, bioinformatic analysis revealed that 19 out of the 31 known dnd gene clusters, contain only four genes (dndb-e), lacking a key cysteine desulfurase corresponding gene. there are multiple cysteine desulfurase genes in escherichia coli, but which one ...201223240007
salmonella enterica serovar typhi variants in long-term carriers.long-term typhoid carriers can simultaneously excrete salmonella enterica serovar typhi variants with considerable genetic differences, a situation that complicates the interpretation of the subtyping data used in outbreak investigations and disease surveillance.201323241373
l-asparaginase ii produced by salmonella typhimurium inhibits t cell responses and mediates virulence.salmonella enterica serovar typhimurium avoids clearance by the host immune system by suppressing t cell responses; however, the mechanisms that mediate this immunosuppression remain unknown. we show that s. typhimurium inhibit t cell responses by producing l-asparaginase ii, which catalyzes the hydrolysis of l-asparagine to aspartic acid and ammonia. l-asparaginase ii is necessary and sufficient to suppress t cell blastogenesis, cytokine production, and proliferation and to downmodulate express ...201223245323
intranasal vaccination in mice with an attenuated salmonella enterica serovar 908htr a expressing cp15 of cryptosporidium: impact of malnutrition with preservation of cytokine secretion.cryptosporidium is a protozoan parasite associated with acute and persistent diarrhea that, even in asymptomatic persons, can impair normal growth and potentially cognitive and physical development in young children. the recent availability of the complete gene sequence for cryptosporidium hominis antigen cp15 allows examination of innovative vaccine regimens involving intra-nasal antigen priming with live bacterial vectors applicable to human populations. we used a recently described weaned mou ...201323246541
detection of salmonella enterica serovar enteritidis using real time pcr, immunocapture assay, pna fish and standard culture methods in different types of food samples.several methods for the rapid and specific detection of salmonella in food samples have been described. here, we compare 4 of those methods in terms of assay time, procedure complexity, detection limit, sensitivity, specificity and accuracy. milk, eggs and mayonnaise samples were artificially contaminated with salmonella enterica serovar enteritidis cell concentrations ranging from 1×10(-2) to 1×10(2) cfu per 25 g or ml of food. samples were then pre-enriched and analyzed by either: i) real-time ...201323246608
the b subunit of an ab5 toxin produced by salmonella enterica serovar typhi up-regulates chemokines, cytokines, and adhesion molecules in human macrophage, colonic epithelial, and brain microvascular endothelial cell lines.the principal function of bacterial ab5 toxin b subunits is to interact with glycan receptors on the surfaces of target cells and mediate the internalization of holotoxin. however, b subunit-receptor interactions also have the potential to impact cell signaling pathways and, in so doing, contribute to pathogenesis independently of the catalytic (toxic) a subunits. various salmonella enterica serovars, including salmonella enterica serovar typhi, encode an ab5 toxin (artab), the a subunit of whic ...201323250951
dna sequence analysis of plasmids from multidrug resistant salmonella enterica serotype heidelberg isolates.salmonella enterica serovar heidelberg is among the most detected serovars in swine and poultry, ranks among the top five serotypes associated with human salmonellosis and is disproportionately associated with invasive infections and mortality in humans. salmonella are known to carry plasmids associated with antimicrobial resistance and virulence. to identify plasmid-associated genes in multidrug resistant s. enterica serovar heidelberg, antimicrobial resistance plasmids from five isolates were ...201223251446
antimicrobial activity of plant essential oils against escherichia coli o157:h7 and salmonella on lettuce.foodborne outbreaks associated with the consumption of fresh produce have increased. in an effort to identify natural antimicrobial agents as fresh produce-wash, the effect of essential oils in reducing enteric pathogens on iceberg and romaine lettuce was investigated. lettuce pieces were inoculated with a five-strain cocktail of escherichia coli o157:h7 or salmonella enterica (5 log cfu/g) and then immersed in a treatment solution containing 5 ppm free chlorine, cinnamaldehyde, or sporan(®) (80 ...201323256843
zoonotic fecal pathogens and antimicrobial resistance in county fair animals.livestock fairs present a unique opportunity for the public to experience close contact with animals, but may also expose people to zoonotic pathogens through contact with animal feces. the goal of this study was to screen cattle, sheep, goat, chicken, rabbit and horse feces from a livestock fair in california for the potentially zoonotic pathogens escherichia coli o157:h7, salmonella, campylobacter, vibrio, cryptosporidium and giardia spp., as well as determining the level of antimicrobial resi ...201323260373
safety and protective efficacy of live attenuated salmonella gallinarum mutants in rhode island red chickens.salmonella enterica serovar gallinarum is the causative agent of fowl typhoid, an important systemic disease of poultry with economic consequences in developing nations. a live attenuated orally applied s. gallinarum vaccine could provide a low cost method for controlling this disease. we constructed s. gallinarum strains in which the expression of the crp, rfc and rfah genes, important for virulence of salmonella typhimurium in mice, were under the control of an arabinose-regulated promoter. we ...201323261043
sero- and genotyping of salmonella in slaughter pigs, from farm to cutting plant, with a focus on the slaughter process.the objective of this study was to investigate the role of the slaughtering process in salmonella carcass contamination by typing isolates recovered previously in a double study of the following: (1) a tracking survey from the farm to the slaughterhouse and (2) a survey of the slaughterhouse environment (i.e., lairage area, slaughter line, cutting plant and carcasses). the salmonella serotypes identified on the carcasses of the 16 tracked batches were frequently linked to lairage, whereas the se ...201323261811
critical role of type i interferon-induced macrophage necroptosis during infection with salmonella enterica serovar typhimurium. 201323262973
salmonella infection in a remote, isolated wild pig population.although wild pig populations are known to sometimes be infected by salmonella, the situation in australia has received little attention and few population-based, planned studies have been conducted. understanding the distribution of salmonella infections within wild pig populations allows the potential hazard posed to co-grazing livestock to be assessed. we sampled a remote and isolated wild pig population in northwestern australia. faecal and mesenteric lymph node samples were collected from 6 ...201323266110
microbiological study of biofilm formation in isolates of salmonella enterica typhimurium dt104 and dt104b cultured from the modern pork chain.the purpose of this study was to characterise 172 salmonella typhimurium isolates taken from the pork chain for their biofilm forming abilities and to analyse their potential to survive on food processing surfaces. many salmonella have the ability to form biofilms. these natural structures, elaborated by bacteria are important in food production because their formation contributes to bacterial survival. adherent bacterial cells are more resilient to displacement strategies including physical and ...201323266499
sesbania grandiflora leaf extract mediated green synthesis of antibacterial silver nanoparticles against selected human pathogens.simple, effective and rapid approach for the green synthesis of silver nanoparticles (agnps) using leaf extract of sesbania grandiflora and their in vitro antibacterial activity against selected human pathogens has been demonstrated in the study. various instrumental techniques were adopted to characterize the synthesized agnps viz. uv-vis, ftir, xrd, tem, edx and afm. surface plasmon spectra for agnps are centered at 422 nm with dark brown color. the synthesized agnps were found to be spherical ...201223270884
antimicrobial susceptibility and multi-drug resistance of salmonella enterica subspecies enterica serovars in sudan.this study was undertaken to determine the antimicrobial resistance patterns of salmonella enterica subspecies enterica recovered from human, food, water, and animal samples collected in khartoum state, sudan. a total of 64 salmonella isolates belonging to 28 different serovars were tested for their susceptibility to 13 antimicrobial agents. the majority of isolates (98.4 %) were resistant to at least one antimicrobial agent. isolates were frequently resistant to ampicillin (90.6 %), cephalexin ...201323271416
azithromycin and ciprofloxacin resistance in salmonella bloodstream infections in cambodian adults.salmonella enterica is a frequent cause of bloodstream infection (bsi) in asia but few data are available from cambodia. we describe salmonella bsi isolates recovered from patients presenting at sihanouk hospital centre of hope, phnom penh, cambodia (july 2007-december 2010).201223272255
optimized microbial dna extraction from diarrheic stools.the detection of enteropathogens in stool specimens increasingly relies on the detection of specific nucleic acid sequences. we observed that such detection was hampered in diarrheic stool specimens and we set-up an improved protocol combining lyophilization of stools prior to a semi-automated dna extraction.201223273000
systemic exposure, tissue distribution, and disease evolution of a high solubility ciprofloxacin-aluminum complex in a murine model of septicemia induced by salmonella enterica serotype enteritidis.a new pharmaceutical derivative obtained by stoichiometric complexation of ciprofloxacin (cip) with aluminum (cip-complex) has been investigated and reported in this study. such product has high solubility in the gastrointestinal ph range and was successful in the development of optimized formulations while maintaining its antimicrobial potency. the systemic exposure, tissue distribution, and the disease evolution after given cip-complex were assessed. the systemic exposure and distribution in i ...201323273286
a weibull model to describe antimicrobial kinetics of oregano and lemongrass essential oils against salmonella enteritidis in ground beef during refrigerated storage.the antimicrobial effect of oregano (origanum vulgare l.) and lemongrass (cymbopogon citratus (dc.) stapf.) essential oils (eos) against salmonella enterica serotype enteritidis in in vitro experiments, and inoculated in ground bovine meat during refrigerated storage (4±2 °c) for 6 days was evaluated. the weibull model was tested to fit survival/inactivation bacterial curves (estimating of p and δ parameters). the minimum inhibitory concentration (mic) value for both eos on s. enteritidis was 3. ...201323273476
β-lactamases, transferable quinolone resistance determinants, and class 1 integron-mediated antimicrobial resistance in human clinical salmonella enterica isolates of non-typhimurium serotypes.this work investigates the occurrence and features of class 1 integrons and the presence of transferable quinolone resistance determinants (tqrd) among 382 clinical salmonella enterica isolates of non-typhimurium serotypes as well as the β-lactamases produced by amoxicillin-resistant isolates. these isolates were recovered in 2001 and from 2004 to 2009 from patients from the health region of terres de l'ebre (catalonia, spain) and comprised 41 different serotypes, mostly of serovar enteritidis ( ...201323273534
exploring the immune response of porcine mesenteric lymph nodes to salmonella enterica serovar typhimurium: an analysis of transcriptional changes, morphological alterations and pathogen burden.infections caused by salmonella enterica serovar typhimurium (s. typhimurium) cause important economic problems in the swine industry and threaten the integrity of a safe and healthy food supply. controlling the prevalence of salmonella in pig production requires a thorough knowledge of the response processes that occurs in the gut associated immune tissues. to explore the in vivo porcine response to s. typhimurium, mln samples from four control pigs and twelve infected animals at 1, 2 and 6 day ...201323274115
molecular serotyping of salmonella enterica by complete rpob gene sequencing.serotyping has been the gold standard for identifying salmonella, but it requires large amounts of standard antisera. multilocus sequence typing (mlst) has been applied to identify salmonella serovars, but the recombination of 4-7 housekeeping genes and multiple analytic steps diminish its applicability. in the present study, we determined the complete sequences of the rna polymerase beta subunit gene (rpob) and 7 housekeeping genes (aroc, dnan, hemd, hisd, pure, suca, and thra) for 76 strains o ...201223274983
mobile effector proteins on phage genomes.bacteriophage genomes found in a range of bacterial pathogens encode a diverse array of virulence factors ranging from superantigens or pore forming lysins to numerous exotoxins. recent studies have uncovered an entirely new class of bacterial virulence factors, called effector proteins or effector toxins, which are encoded within phage genomes that reside among several pathovars of escherichia coli and salmonella enterica. these effector proteins have multiple domains resulting in proteins that ...201223275865
[role of pathogen surveillance and subtyping in outbreak recognition of food-borne bacterial infections. microbiological perspective - aims, methods and prospects of pathogen subtyping].the recognition of infection clusters via determination of clonal relationships between pathogen isolates represents the major aim of pathogen subtyping during outbreaks. in addition, a continuing and comprehensive subtyping of pathogen isolates is a prerequisite for early recognition of changes within pathogen populations, especially of new pathogen types and variants. here, in an exemplary manner, we outline the current practice in germany for three important agents of food-borne infections, s ...201323275955
characterization of citrobacter sp. line 328 as a source of vi for a vi-crm(197) glycoconjugate vaccine against salmonella typhi.salmonella enterica serovar typhi is the causative agent of typhoid fever with over 22 million cases and over 200,000 deaths reported annually. a vaccine is much needed for use in young children and the novartis vaccines institute for global health (nvgh) is developing a conjugate vaccine which targets s. typhi vi capsular polysaccharide.201223277501
human isolates of salmonella enterica serovar typhimurium from taiwan displayed significantly higher levels of antimicrobial resistance than those from denmark.salmonella enterica serovar typhimurium is a major zoonotic pathogen with a high prevalence of antimicrobial resistance. this pathogen can disseminate across borders and spread far distances via the food trade and international travel. in this study, we compared the genotypes and antimicrobial resistance of 378 s. typhimurium isolates collected in taiwan and denmark between 2009 and 2010. genotyping revealed that many s. typhimurium strains were concurrently circulating in taiwan, denmark and ot ...201323279815
salmonella typhimurium's transthyretin-like protein is a host-specific factor important in fecal survival in chickens.the transthyretin-like protein (tlp) from salmonella enterica subspecies i is a periplasmic protein with high level structural similarity to a protein found in mammals and fish. in humans, the protein homologue, transthyretin, binds and carries retinol and thyroxine, and a series of other, unrelated aromatic compounds. here we show that the amino acid sequence of the tlp from different species, subspecies and serovars of the salmonella genus is highly conserved and demonstrate that the tlp gene ...201223284609
evaluation of salmonella enterica serovar typhimurium ttss-2 deficient fur mutant as safe live-attenuated vaccine candidate for immunocompromised mice.salmonella enterica serovar typhimurium has been extensively exploited as live attenuated vaccines (lav) which generally confers better protection than killed or subunit vaccines. however, many lav are limited by their inherent ability to access systemic organs in many of the vaccinated hosts, especially those which are immunocompromised. we evaluated the efficacy of a live-attenuated spi2-deficient (δssav) s. typhimurium vaccine candidate (mt13) that additionally devoids the ferric uptake regul ...201223284865
early diagnosis of typhoid fever by nested pcr for flagellin gene of salmonella enterica serotype typhi.typhoid fever caused by salmonella typhi continues to be a major health problem in spite of the use of antibiotics and the development of newer antibacterial drugs. inability to make an early laboratory diagnosis and resort to empirical therapy, often lead to increased morbidity and mortality in cases of typhoid fever. this study was aimed to optimize a nested pcr for early diagnosis of typhoid fever and using it as a diagnostic tool in culture negative cases of suspected typhoid fever.201223287134
pitfalls of interpreting ciprofloxacin minimum inhibitory concentrations in salmonella enterica serovar typhi. 201223287141
molecular characterization of the inve regulator in the secretion of type iii secretion translocases in salmonella enterica serovar typhimurium.the type iii secretion systems (t3sss) are exploited by many gram-negative pathogenic bacteria to deliver a set of effector proteins into the host cytosol during cell entry. the t3ss of salmonella enterica serovar typhimurium is composed of more than 20 proteins that constitute the membrane-associated base, the needle and the tip complex at the distal end of the t3ss needle. membrane docking and piercing between the t3ss and host cells is followed by the secretion of effector proteins. therefore ...201323288540
occurrence of β-lactamase genes among non-typhi salmonella enterica isolated from humans, food animals, and retail meats in the united states and canada.non-typhi salmonella cause over 1.7 million cases of gastroenteritis in north america each year, and food-animal products are commonly implicated in human infections. for invasive infections, antimicrobial therapy is indicated. in north america, the antimicrobial susceptibility of salmonella is monitored by the u.s. national antimicrobial resistance monitoring system (narms) and the canadian integrated program for antimicrobial resistance surveillance (cipars). in this study, we determined the s ...201323289438
an essential serotype recognition pocket on phage p22 tailspike protein forces salmonella enterica serovar paratyphi a o-antigen fragments to bind as nonsolution conformers.bacteriophage p22 recognizes o-antigen polysaccharides of salmonella enterica subsp. enterica (s.) with its tailspike protein (tsp). in the serovars s. typhimurium, s. enteritidis, and s. paratyphi a, the tetrasaccharide repeat units of the respective o-antigens consist of an identical main chain trisaccharide but different 3,6-dideoxyhexose substituents. here, the epimers abequose, tyvelose and paratose determine the specific serotype. p22 tsp recognizes o-antigen octasaccharides in an extended ...201323292517
[genetic determinants of secreted lysozyme inhibitors and enterobacteria anti-lysozyme phenotype].determination of interconnection of genetic determinants of secreted lysozyme inhibitors with enterobacteria anti-lysozyme phenotype.201323297624
colonization of internal organs by salmonella enteritidis in experimentally infected laying hens housed in conventional or enriched cages.more human illnesses caused by salmonella enterica subspecies enterica serovar enteritidis throughout the world have been linked to the consumption of contaminated eggs than to any other food vehicle. deposition of this pathogen in the edible contents of eggs occurs when systemic infections of laying hens involve colonization of reproductive organs. in recent years, the consequences of different housing systems for laying flocks have become the focus of international attention from both animal w ...201323300315
an allele of an ancestral transcription factor dependent on a horizontally acquired gene product.changes in gene regulatory circuits often give rise to phenotypic differences among closely related organisms. in bacteria, these changes can result from alterations in the ancestral genome and/or be brought about by genes acquired by horizontal transfer. here, we identify an allele of the ancestral transcription factor pmra that requires the horizontally acquired pmrd gene product to promote gene expression. we determined that a single amino acid difference between the pmra proteins from the hu ...201223300460
isolation of salmonella mutants resistant to the inhibitory effect of salicylidene acylhydrazides on flagella-mediated motility.salicylidene acylhydrazides identified as inhibitors of virulence-mediating type iii secretion systems (t3sss) potentially target their inner membrane export apparatus. they also lead to inhibition of flagellar t3ss-mediated swimming motility in salmonella enterica serovar. typhimurium. we show that inp0404 and inp0405 act by reducing the number of flagella/cell. these molecules still inhibit motility of a salmonella δflih-flii-flij/flhb((p28t)) strain, which lacks three soluble components of th ...201323300965
evaluation antibacterial activity of quaternary-based chitin/chitosan derivatives in vitro.total of 3 water-soluble quaternary-based chitin/chitosan derivatives, which have an identical molecular weight and anion, were synthesized and characterized. their antibacterial activities against salmonella cholerae-suis and bacillus subtilis were evaluated in vitro. the polysaccharides exhibited the antibacterial efficiency. their minimum inhibitory concentration (mic) values vary from 0.02 to 20.48 mg/ml, and their minimum bactericidal concentration (mbc) values vary from 0.08 to 40.96 mg/ml ...201323301607
escherichia coli o157:h7 induces stronger plant immunity than salmonella enterica typhimurium sl1344.consumption of fresh produce contaminated with bacterial human pathogens has resulted in various, sometimes deadly, disease outbreaks. in this study, we assessed plant defense responses induced by the fully pathogenic bacteria escherichia coli o157:h7 and salmonella enterica serovar typhimurium sl1344 in both arabidopsis thaliana and lettuce (lactuca sativa). unlike sl1344, o157:h7 induced strong plant immunity at both pre-invasion and post-invasion steps of infection. for instance, o157:h7 trig ...201323301812
virulence and stress-related periplasmic protein (visp) in bacterial/host associations.gram-negative bacteria have an outer membrane containing lps. lps is constituted of an oligosaccharide portion and a lipid-a moiety that embeds this molecule within the outer membrane. lps is a pathogen-associated molecular pattern, and several pathogens modify their lipid-a as a stealth strategy to avoid recognition by the innate immune system and gain resistance to host factors that disrupt the bacterial cell envelope. an essential feature of salmonella enterica typhimurium pathogenesis is its ...201323302685
immune profiling with a salmonella typhi antigen microarray identifies new diagnostic biomarkers of human typhoid.current serological diagnostic assays for typhoid fever are based on detecting antibodies against salmonella lps or flagellum, resulting in a high false-positive rate. here we used a protein microarray containing 2,724 salmonella enterica serovar typhi antigens (>63% of proteome) and identified antibodies against 16 igg antigens and 77 igm antigens that were differentially reactive among acute typhoid patients and healthy controls. the igg target antigens produced a sensitivity of 97% and specif ...201323304434
hunanamycin a, an antibiotic from a marine-derived bacillus hunanensis.hunanamycin a, the first natural product with a pyrido[1,2,3-de]quinoxaline-2,3-dione core, was isolated from a marine-derived bacillus hunanensis. hunanamycin a is related to a degradation product of riboflavin but has undergone an n-prenylation and subsequent cyclization. the structure, including stereochemistry, was determined by nmr and ms methods. hunanamycin a exhibits a minimum inhibitory concentration (mic) of 12.4 μm against the bacterial pathogen salmonella enterica.201323305153
antioxidant and antimicrobial properties of monofloral bee pollen.the main aim of this study was to determine antioxidant properties and antibacterial activity of monofloral bee pollen samples to pathogenic bacteria. these samples were collected in different localities in slovakia. the antioxidant properties of examined plant species were different and decreasing in the following order: brassica napus subsp. napus l > papaver somniferum l. > helianthus annuus l. the antimicrobial effect of the bee product samples were tested by using the agar well diffusion me ...201323305281
role of the salmonella enterica serovar typhi fur regulator and small rnas rfra and rfrb in iron homeostasis and interaction with host cells.iron is an essential element but can be toxic at high concentrations. therefore, its acquisition and storage require tight control. salmonella encodes the global regulator fur (ferric uptake regulator) and the small regulatory non-coding rnas (srnas) rfra and rfrb, homologues of ryhb. the role of these iron homeostasis regulators was investigated in salmonella enterica serovar typhi (s. typhi). strains containing either single or combined deletions of these regulators were obtained. the mutants ...201323306672
lack of effect of the salmonella deubiquitinase ssel on the nf-κb pathway.intracellular replication of salmonella enterica requires effector proteins translocated across the salmonella-containing vacuolar membrane by salmonella pathogenicity island-2 (spi-2) encoded type iii secretion system (t3ss). the spi-2 t3ss effector ssel is a deubiquitinase that contributes to virulence in mice. previous work has produced conflicting evidence as to the involvement of ssel in interference with the nf-κb pathway. to attempt to clarify these discrepancies, we compared mrna levels ...201323308136
reactive arthritis following salmonella infection: a population-based study.to study the incidence and clinical picture of salmonella-associated reactive arthritis (rea), as well as other reactive musculoskeletal symptoms and the arthritogenicity of various salmonella enterica ssp. enterica serotypes in the population.201323311895
characterization of an acid-inducible sulfatase in salmonella enterica serovar typhimurium.sulfatases of enteric bacteria can provide access to heavily sulfated mucosal glycans. in this study, we show that asla (stm0084) of salmonella enterica serovar typhimurium lt2 encodes a sulfatase that requires mildly acidic ph for its expression and activity. asla is not regulated by sulfur compounds or tyramine but requires the envz-ompr and phopq regulatory systems, which play an important role in pathogenesis.201323315743
a genomewide mutagenesis screen identifies multiple genes contributing to vi capsular expression in salmonella enterica serovar typhi.a transposon-based, genomewide mutagenesis screen exploiting the killing activity of a lytic viii bacteriophage was used to identify salmonella enterica serovar typhi genes that contribute to vi polysaccharide capsule expression. genes enriched in the screen included those within the viab locus (tviabcde and vexabcde) as well as oxyr, bara/sira, and yrff, which have not previously been associated with vi expression. the role of these genes in vi expression was confirmed by constructing defined n ...201323316043
bactericidal activities of health-promoting, food-derived powders against the foodborne pathogens escherichia coli, listeria monocytogenes, salmonella enterica, and staphylococcus aureus.we evaluated the relative bactericidal activities (ba(50) ) of 10 presumed health-promoting food-based powders (nutraceuticals) and, for comparison, selected known components against the following foodborne pathogens: escherichia coli o157:h7, salmonella enterica, listeria monocytogenes, and staphylococcus aureus. the relative activities were evaluated using quantitative bactericidal activity [(ba(50) value, defined as the percentage of the sample in the assay mixture that resulted in a 50% decr ...201323317422
antimicrobial resistance of salmonella enterica isolates from bulk tank milk and milk filters in the united states.salmonella isolates were recovered from bulk tank milk as part of the national animal health monitoring system (nahms) dairy 2002 and 2007 surveys. in-line milk filters were also tested in the 2007 survey. the objective of this study was to determine the prevalence of antimicrobial resistance among salmonella enterica isolates from bulk milk and milk filters in the nahms dairy 2002 and 2007 surveys and to further characterize resistant isolates. susceptibilities to 15 antibiotics were determined ...201323317852
thermal inactivation of salmonella enteritidis pt 30 in almond kernels as influenced by water activity.salmonellosis outbreaks related to consumption of raw almonds have encouraged the scientific community to study the inactivation kinetics of pathogens in this dry commodity. however, the low moisture content of the product presents a challenge for thermal control, because the time required to achieve the desired thermal inactivation of microorganisms increases sharply with reduced moisture content and water activity. in this study, we explored and modeled the heat inactivation of salmonella ente ...201323317853
initial contamination of chicken parts with salmonella at retail and cross-contamination of cooked chicken with salmonella from raw chicken during meal preparation.the current study was undertaken to acquire data on contamination of chicken parts with salmonella at retail and to acquire data on cross-contamination of cooked chicken with salmonella from raw chicken during meal preparation. whole raw chickens (n = 31) were obtained from local retail stores and cut into two wings, two breasts without skin or bones, two thighs, and two drumsticks. data for cross-contamination were obtained by cutting up a sterile, cooked chicken breast with the same board and ...201323317854
inhibitory effect of cinnamon powder on pathogen growth in laboratory media and oriental-style rice cakes (sulgidduk).there has been an increasing interest in the use of natural plant materials as alternative food preservatives. we examined the antimicrobial effects of natural plant materials used as additives against foodborne pathogens in laboratory media and sulgidduk, oriental-style rice cakes. cinnamon, mugwort, and garlic powder solutions (3%) were tested for their antimicrobial activities against pathogens in laboratory media. sulgidduk prepared with different amounts of cinnamon powder (1, 3, and 6%) wa ...201323317869
intratumoral injection of attenuated salmonella vaccine can induce tumor microenvironmental shift from immune suppressive to immunogenic.attenuated salmonella vaccines show therapeutic anti-cancer effects, but the underlying mechanism has not been well investigated. in the current study, intratumoral (i.t.) injection of recombinant attenuated salmonella enterica serovar typhimurium vaccine (rasv) significantly inhibited her-2/neu-expressing tumor growth. although depletion of cd8(+) cells in rasv-treated mice significantly restored tumor growth, the induction of her-2/neu-specific cytotoxic t lymphocytes (ctls) was not well corre ...201323318147
salmonella polarises peptide-mhc-ii presentation towards an unconventional type b cd4+ t-cell response.distinct peptide-mhc-ii complexes, recognised by type a and b cd4(+) t-cell subsets, are generated when antigen is loaded in different intracellular compartments. conventional type a t cells recognize their peptide epitope regardless of the route of processing, whereas unconventional type b t cells only recognise exogenously supplied peptide. type b t cells are implicated in autoimmune conditions and may break tolerance by escaping negative selection. here we show that salmonella differentially ...201323319341
ingress of salmonella enterica typhimurium into tomato leaves through hydathodes.internal contamination of salmonella in plants is attracting increasing attention for food safety reasons. in this study, three different tomato cultivars "florida lanai", "crown jewel", "ailsa craig" and the transgenic line sp5 of "ailsa craig" were inoculated with 1 µl gfp-labeled salmonella typhimurium through guttation droplets at concentrations of 10(9) or 10(7) cfu/ml. survival of salmonella on/in tomato leaves was detected by both direct plating and enrichment methods. salmonella cells su ...201323320087
development of ceftriaxone resistance affects the virulence properties of salmonella enterica serotype typhimurium strains.development of antibiotic resistance may alter the virulence properties of bacterial organisms. in this study, nine clinical ceftriaxone-susceptible salmonella enterica serotype typhimurium strains were subjected to stepwise selection with increasing concentrations of ceftriaxone in culture media. mutations in virulence-associated genes and antibiotic efflux genes were analyzed by polymerase chain reaction (pcr) and dna sequencing. the expression levels of virulence genes inva and stn as well as ...201323320420
characterization of salmonella food isolates with concurrent resistance to ceftriaxone and ciprofloxacin.foodborne salmonellosis is an important public health problem worldwide. most human salmonella infections occur through the consumption of contaminated food of animal origin. the study reported the first isolation of two salmonella enterica serovar oranienburg strains from pork in china with concurrent resistance to ciprofloxacin and ceftriaxone. both isolates also showed resistance to norfloxacin, trimethoprim-sulfamethoxazole, and chloramphenicol, and an elevated minimal inhibitory concentrato ...201323320422
genetic types, gene repertoire, and evolution of isolates of the salmonella enterica serovar 4,5,12:i:- spanish clone assigned to different phage types.salmonella enterica subsp. enterica 4,[5],12:i:- is one of the most prevalent serovars associated with human infections worldwide. two multidrug-resistant clones, designated spanish and european clones, are recognized as having importance for public health and are subject to control measures in the european union. in this study, 23 clinical isolates belonging to the spanish clone were characterized by multilocus sequence typing, multiple-locus variable number tandem repeat analysis (mlva), pcr a ...201323325816
current antibiogram and clonal relatedness among drug-resistant salmonella enterica serovar typhi in northern india.in view of the changing sensitivity pattern of salmonella, this study was carried out to investigate the current antibiogram and clonal relatedness among the drug-resistant salmonella enterica serovar typhi in northern india.201323330551
the plasmidome of a salmonella enterica serovar derby isolated from pork meat.the complete nucleotide sequences of four plasmids hosted by a salmonella enterica serovar. derby strain 6mk1 isolated from pork were determined by shotgun sanger sequencing. a 107,637 base pairs (bp) conjugative plasmid psd107 containing 150 putative coding sequences (cds) could be assigned to the narrow host range incompatibility group inci1. a detailed annotation of all cds was carried out, revealing the presence of genes needed for plasmid replication, conjugal transfer, plasmid partitioning ...201323333216
active modification of host inflammation by salmonella.the dampening of host immune responses is a critical aspect of pathogenesis for the enteropathogen salmonella enterica. our laboratory has recently described a role for the secreted effector gogb in disruption of nfκb activation and limitation of the host inflammatory response to infection. gogb alters the nfκb pathway by preventing iκb degradation by the host scf e3 ubiquitin ligase, through an interaction with skp1 and fbxo22. the prevention of nfκb activation through this interaction dampens ...201323333857
survival of food-borne pathogens on natural black table olives after post-processing contamination.the aim of this study was to evaluate the survival of salmonella, escherichia coli o157:h7, listeria monocytogenes, and staphylococcus aureus on natural black olives during aerobic storage without brine and to conclude about the safety of this fermented food. fermented black olives (ph 3.95; nacl 6.02%) were artificially inoculated with 4 strains of salmonella enterica ser. enteritidis, 4 strains of s. enterica ser. typhimurium, 3 strains of e. coli o157:h7, 3 strains of l. monocytogenes, and 3 ...201323334099
long-term survival of escherichia coli o157:h7 and salmonella enterica on butterhead lettuce seeds, and their subsequent survival and growth on the seedlings.the long-term survival of enteric pathogens on butterhead lettuce seeds, and their subsequent survival and growth on seedlings were investigated. lettuce seeds were inoculated at a high level with two salmonella enterica and two escherichia coli o157:h7 strains each (±8 log₁₀ cfu/g seed) and the survival of the pathogens was monitored over two years using standard plating techniques on selective medium. the salmonella strains (serovars typhimurium and thompson) survived significantly better on t ...201323334101
a t-bet gradient controls the fate and function of ccr6-rorγt+ innate lymphoid cells.at mucosal surfaces, the immune system should not initiate inflammatory immune responses to the plethora of antigens constantly present in the environment, but should remain poised to unleash a potent assault on intestinal pathogens. the transcriptional programs and regulatory factors required for immune cells to switch from homeostatic (often tissue-protective) function to potent antimicrobial immunity are poorly defined. mucosal retinoic-acid-receptor-related orphan receptor-γt-positive (rorγt ...201323334414
inactivation of pathogens in feces by desiccation and urea treatment for application in urine-diverting dry toilets.ecological sanitation technologies can be effective in providing health and environmental pollution control if they can efficiently reduce the pathogenicity of microorganisms carried in fecal material to safe levels. this study evaluated the sanitizing effects of different additives for dry treatment of feces from urine-diverting dry toilets, based on inactivation of enterococcus faecalis, salmonella enterica serovar typhimurium, bacteriophages ms2 and φx, and ascaris suum. the additives, ash (a ...201323335764
wksl3, a new biocontrol agent for salmonella enterica serovars enteritidis and typhimurium in foods: characterization, application, sequence analysis, and oral acute toxicity study.of the salmonella enterica serovars, s. enteritidis and s. typhimurium are responsible for most of the salmonella outbreaks implicated in the consumption of contaminated foods in the republic of korea. because of the widespread occurrence of antimicrobial-resistant salmonella in foods and food processing environments, bacteriophages have recently surfaced as an alternative biocontrol tool. in this study, we isolated a virulent bacteriophage (wksl3) that could specifically infect s. enteritidis, ...201323335772
outbreak of salmonella typhi enteric fever in sub-urban area of north india: a public health perspective.outbreaks of enteric fever are a major health concern not only due to significant human morbidity and mortality but also fear of spread of multidrug resistant strains. we report an outbreak of enteric fever caused by salmonella enterica serotype typhi in a suburban area, in city chandigarh of north india. twenty-seven strains of s. typhi were isolated from blood cultures over a period of two weeks with 18 of these 27 patients residing in the same area. maximum cases were in the age group 5-14 ye ...201323339924
reassessing the type i dehydroquinate dehydratase catalytic triad: kinetic and structural studies of glu86 mutants.dehydroquinate dehydratase (dhqd) catalyzes the third reaction in the biosynthetic shikimate pathway. type i dhqds are members of the greater aldolase superfamily, a group of enzymes that contain an active site lysine that forms a schiff base intermediate. three residues (glu86, his143, and lys170 in the salmonella enterica dhqd) have previously been proposed to form a triad vital for catalysis. while the roles of lys170 and his143 are well defined-lys170 forms the schiff base with the substrate ...201323341204
contribution of thy1+ nk cells to protective ifn-γ production during salmonella typhimurium infections.ifn-γ is critical for immunity against infections with intracellular pathogens, such as salmonella enterica. however, which of the many cell types capable of producing ifn-γ controls salmonella infections remains unclear. using a mouse model of systemic salmonella infection, we observed that only a lack of all lymphocytes or cd90 (thy1)(+) cells, but not the absence of t cells, retinoic acid-related orphan receptor (ror)-γt-dependent lymphocytes, (nk)1.1(+) cells, natural killer t (nkt), and/or ...201323345426
antimicrobial resistance genes in multidrug-resistant salmonella enterica isolated from animals, retail meats, and humans in the united states and canada.salmonella enterica is a prevalent foodborne pathogen that can carry multidrug resistance (mdr) and pose a threat to human health. identifying the genetics associated with mdr in salmonella isolated from animals, foods, and humans can help determine sources of mdr in food animals and their impact on humans. s. enterica serovars most frequently carrying mdr from healthy animals, retail meats, and human infections in the united states and canada were identified and isolates resistant to the larges ...201323350745
systemic administration of lipopolysaccharide in laying hens stimulates antimicrobial properties of egg white against staphylococcus aureus.the natural protective system of eggs relies on egg yolk immunoglobulins and on antimicrobial proteins/peptides mainly concentrated in the egg white. there is much evidence concerning the specific stimulation of immunoglobulins by antigens but to date, the influence of the hen milieu on the regulation of the egg innate molecular immunity has not been established. to explore the hypothesis of modulation in egg antimicrobial molecules, laying hens were immune-challenged with intravenous injections ...201323351641
the molecular adjuvant mc3d enhances the immunogenicity of fima from type i fimbriae of salmonella enterica serovar enteritidis.the fimbriae of salmonella enterica serovar enteritidis are used for colonization and invasion into host cells, and have drawn considerable interest because fimbriae can serve as potential immunogens against many pathogenic bacteria that colonize on epithelial surfaces. the purpose of the study is to use a molecular adjuvant, c3d, to enhance the immunogenicity of fima proteins against salmonella enterica serovar enteritidis.201423352331
microfluidic chip-based detection and intraspecies strain discrimination of salmonella serovars derived from whole blood of septic mice.salmonella is a zoonotic pathogen that poses a considerable public health and economic burden in the united states and worldwide. resultant human diseases range from enterocolitis to bacteremia to sepsis and are acutely dependent on the particular serovar of salmonella enterica subsp. enterica, which comprises over 99% of human-pathogenic s. enterica isolates. point-of-care methods for detection and strain discrimination of salmonella serovars would thus have considerable benefit to medical, vet ...201323354710
stochasticity in colonial growth dynamics of individual bacterial cells.conventional bacterial growth studies rely on large bacterial populations without considering the individual cells. individual cells, however, can exhibit marked behavioral heterogeneity. here, we present experimental observations on the colonial growth of 220 individual cells of salmonella enterica serotype typhimurium using time-lapse microscopy videos. we found a highly heterogeneous behavior. some cells did not grow, showing filamentation or lysis before division. cells that were able to gro ...201323354712
the type vi secretion system encoded in salmonella pathogenicity island 19 is required for salmonella enterica serotype gallinarum survival within infected macrophages.salmonella enterica serotype gallinarum is the causative agent of fowl typhoid, a disease characterized by high morbidity and mortality that causes major economic losses in poultry production. we have reported that s. gallinarum harbors a type vi secretion system (t6ss) encoded in salmonella pathogenicity island 19 (spi-19) that is required for efficient colonization of chicks. in the present study, we aimed to characterize the spi-19 t6ss functionality and to investigate the mechanisms behind t ...201323357385
pathogenicity of yersinia pestis synthesis of 1-dephosphorylated lipid a.synthesis of escherichia coli lpxl, which transfers a secondary laurate chain to the 2' position of lipid a, in yersinia pestis produced bisphosphoryl hexa-acylated lipid a at 37°c, leading to significant attenuation of virulence. our previous observations also indicated that strain χ10015(pcd1ap) (δlpxp32::p(lpxl) lpxl) stimulated a strong inflammatory reaction but sickened mice before recovery and retained virulence via intranasal (i.n.) infection. the development of live, attenuated y. pestis ...201323357387
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 ...201323358892
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 ...201323359678
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