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Sample records for enterica subspecies enterica

  1. Population structure of Salmonella enterica subspecies enterica (subspecies 1)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We sequenced and assembled 354 new Salmonella enterica ssp. enterica genomes. These genomes were chosen to maximize genetic diversity, representing at least 100 different serovars and distinct PFGE patterns within these serovars. 119 of the strains were of known antibiotic resistance,...

  2. Evolutionary Genomics of Salmonella enterica Subspecies.

    PubMed

    Desai, Prerak T; Porwollik, Steffen; Long, Fred; Cheng, Pui; Wollam, Aye; Bhonagiri-Palsikar, Veena; Hallsworth-Pepin, Kymberlie; Clifton, Sandra W; Weinstock, George M; McClelland, Michael

    2013-01-01

    ABSTRACT Six subspecies are currently recognized in Salmonella enterica. Subspecies I (subspecies enterica) is responsible for nearly all infections in humans and warm-blooded animals, while five other subspecies are isolated principally from cold-blooded animals. We sequenced 21 phylogenetically diverse strains, including two representatives from each of the previously unsequenced five subspecies and 11 diverse new strains from S. enterica subspecies enterica, to put this species into an evolutionary perspective. The phylogeny of the subspecies was partly obscured by abundant recombination events between lineages and a relatively short period of time within which subspeciation took place. Nevertheless, a variety of different tree-building methods gave congruent evolutionary tree topologies for subspeciation. A total of 285 gene families were identified that were recruited into subspecies enterica, and most of these are of unknown function. At least 2,807 gene families were identified in one or more of the other subspecies that are not found in subspecies I or Salmonella bongori. Among these gene families were 13 new candidate effectors and 7 new candidate fimbrial clusters. A third complete type III secretion system not present in subspecies enterica (I) isolates was found in both strains of subspecies salamae (II). Some gene families had complex taxonomies, such as the type VI secretion systems, which were recruited from four different lineages in five of six subspecies. Analysis of nonsynonymous-to-synonymous substitution rates indicated that the more-recently acquired regions in S. enterica are undergoing faster fixation rates than the rest of the genome. Recently acquired AT-rich regions, which often encode virulence functions, are under ongoing selection to maintain their high AT content. IMPORTANCE We have sequenced 21 new genomes which encompass the phylogenetic diversity of Salmonella, including strains of the previously unsequenced subspecies arizonae

  3. The Genomic Blueprint of Salmonella enterica subspecies enterica serovar Typhi P-stx-12

    PubMed Central

    Ong, Su Yean; Pratap, Chandra Bhan; Wan, Xuehua; Hou, Shaobin; Rahman, Ahmad Yamin Abdul; Saito, Jennifer A.; Nath, Gopal; Alam, Maqsudul

    2013-01-01

    Salmonella enterica subspecies enterica serovar Typhi is a rod-shaped, Gram-negative, facultatively anaerobic bacterium. It belongs to the family Enterobacteriaceae in the class Gammaproteobacteria, and has the capability of residing in the human gallbladder by forming a biofilm and hence causing the person to become a typhoid carrier. Here we present the complete genome of Salmonella enterica subspecies enterica serotype Typhi strain P-stx-12, which was isolated from a chronic carrier in Varanasi, India. The complete genome comprises a 4,768,352 bp chromosome with a total of 98 RNA genes, 4,691 protein-coding genes and a 181,431 bp plasmid. Genome analysis revealed that the organism is closely related to Salmonella enterica serovar Typhi strain Ty2 and Salmonella enterica serovar Typhi strain CT18, although their genome structure is slightly different. PMID:24019994

  4. The taxonomic structure of Salmonella enterica subspecies enterica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is the leading cause of food-borne bacterial infection in humans and has a high economic burden in agriculture. Strains differ by sequence additions and losses of up to ~10% of each genome. In the last few decades, some serovars have become more common. Many strains have acquired...

  5. Early immune response following Salmonella enterica subspecies enterica serovar Typhimurium infection in porcine jejunal gut loops.

    PubMed

    Meurens, François; Berri, Mustapha; Auray, Gael; Melo, Sandrine; Levast, Benoît; Virlogeux-Payant, Isabelle; Chevaleyre, Claire; Gerdts, Volker; Salmon, Henri

    2009-01-01

    Salmonella enterica subspecies enterica serovar Typhimurium, commonly called S. Typhimurium, can cause intestinal infections in humans and various animal species such as swine. To analyze the host response to Salmonella infection in the pig we used an in vivo gut loop model, which allows the analysis of multiple immune responses within the same animal. Four jejunal gut-loops were each inoculated with 3 x 10(8) cfu of S. Typhimurium in 3 one-month-old piglets and mRNA expressions of various cytokines, chemokines, transcription factors, antimicrobial peptides, toll like and chemokine receptors were assessed by quantitative real-time PCR in the Peyer's patch and the gut wall after 24 h. Several genes such as the newly cloned CCRL1/CCX-CKR were assessed for the first time in the pig at the mRNA level. Pro-inflammatory and T-helper type-1 (Th1) cytokine mRNA were expressed at higher levels in infected compared to non-infected control loops. Similarly, some B cell activation genes, NOD2 and toll like receptor 2 and 4 transcripts were more expressed in both tissues while TLR5 mRNA was down-regulated. Interestingly, CCL25 mRNA expression as well as the mRNA expressions of its receptors CCR9 and CCRL1 were decreased both in the Peyer's patch and gut wall suggesting a potential Salmonella strategy to reduce lymphocyte homing to the intestine. In conclusion, these results provide insight into the porcine innate mucosal immune response to infection with entero-invasive microorganisms such as S. Typhimurium. In the future, this knowledge should help in the development of improved prophylactic and therapeutic approaches against porcine intestinal S. Typhimurium infections. PMID:18922229

  6. Phylogenomic analysis identifies gene gains that define Salmonella enterica subspecies I.

    PubMed

    Lienau, E Kurt; Blazar, Jeffrey M; Wang, Charles; Brown, Eric W; Stones, Robert; Musser, Steven; Allard, Marc W

    2013-01-01

    Comparative methods for analyzing whole genome sequence (WGS) data enable us to assess the genetic information available for reconstructing the evolutionary history of pathogens. We used the comparative approach to determine diagnostic genes for Salmonella enterica subspecies I. S. enterica subsp. I strains are known to infect warm-blooded organisms regularly while its close relatives tend to infect only cold-blooded organisms. We found 71 genes gained by the common ancestor of Salmonella enterica subspecies I and not subsequently lost by any member of this subspecies sequenced to date. These genes included many putative functional phenotypes. Twenty-seven of these genes are found only in Salmonella enterica subspecies I; we designed primers to test these genes for use as diagnostic sequence targets and data mined the NCBI Sequence Read Archive (SRA) database for draft genomes which carried these genes. We found that the sequence specificity and variability of these amplicons can be used to detect and discriminate among 317 different serovars and strains of Salmonella enterica subspecies I. PMID:24204679

  7. Subtyping of Salmonella enterica subspecies I using single nucleotide polymorphisms in adenylate cyclase (cyaA)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methods to rapidly identify serotypes of Salmonella enterica subspecies I are of vital importance for protecting the safety of food. To supplement the serotyping method dkgB-linked intergenic sequence ribotyping (ISR), single nucleotide polymorphisms (SNPs) were characterized within adenylate cyclas...

  8. Salmonella enterica Subspecies diarizonae Maxillary Sinusitis in a Snake Handler: First Report

    PubMed Central

    Horvath, Lukas; Kraft, Marcel; Fostiropoulos, Karolos; Falkowski, Anna; Tarr, Philip E.

    2016-01-01

    In this study, we report the first case of reptile-associated maxillary sinusitis due to Salmonella enterica subspecies diarizonae in a snake handler and the third case of salmonella-associated sinusitis worldwide. The case highlights the potential of respiratory transmission and atypical salmonellosis presentations. PMID:27186588

  9. Evaluation of aroA deletion mutant of Salmonella enterica subspecies enterica serovar Abortusequi for its vaccine candidate potential.

    PubMed

    Alam, Javad; Singh, B R; Hansda, D; Singh, V P; Verma, J C

    2009-11-01

    The present study on a defined deletion aroA mutant (B-26) of Salmonella enterica subspecies enterica serovar Abortusequi (S. Abortusequi) for residual virulence and safety in experimental model revealed that the virulence of the strain was at no difference in any of the cell assays (caprine alveolar macrophages, bovine alveolar macrophages, guinea pig blood mononuclear cells and horse blood mononuclear cells) than that of its parent virulence plasmid cured (S-787) and wild type (E-156) strains. The mutant did not cause any apparent illness in baby guinea pigs (15 days old), adult male and female guinea pigs and also not in pregnant (54-55 days of gestation) guinea pigs through oral (4.2 x 10(9) cfu/ animal) and intramuscular (im) routes (4.2 x 10(7) cfu/ animal). In pregnant females the mutant also induced abortion as its parent (E-156) though to lesser extent (33%) than the parent strain (100%) on inoculation through intravaginal (4.2 x 10(9) cfu/ animal) and intraperitoneal (4.2 x 10(7) cfu/ animal) routes. The babies born from mutant inoculated mothers survived better and were also resistant to intraperitoneal lethal challenge (7.82 x 10(9) cfu/ animal) with 100% protection. Female guinea pigs challenged after 135-165 days of inoculation with the mutant afforded 100% protection from abortion and mortality caused by lethal infection (7.82 x 10(9) cfu/ animal) of wild type S. enterica Abortusequi (E-156). The study revealed that aroA mutant (B-26) was safe through oral and im routes for immunization and afforded 100% protection against salmonellosis for more than 5.5 months in guinea pigs. Although immunization with aroA mutant in experimental model afforded good protection against abortion and mortality induced by S. Abortusequi, further studies are needed in horses to exploit the strain's vaccine potential in the natural host. PMID:20099460

  10. Spatial Variation and Survival of Salmonella enterica Subspecies in a Population of Australian Sleepy Lizards (Tiliqua rugosa).

    PubMed

    Parsons, Sandra K; Bull, C Michael; Gordon, David M

    2015-09-01

    The life cycles of many enteric bacterial species require a transition between two very distinct environments. Their primary habitat is the gastrointestinal tract of the host, while their secondary habitat, during transmission from one host to another, consists of environments external to the host, such as soil, water, and sediments. Consequently, both host and environmental factors shape the genetic structure of enteric bacterial populations. This study examined the distribution of four Salmonella enterica subspecies in a population of sleepy lizards, Tiliqua rugosa, in a semiarid region of South Australia. The lizards living within the 1,920-m by 720-m study site were radio tracked, and their enteric bacteria were sampled at regular intervals throughout their active seasons in the years 2001, 2002, and 2006. Four of the six subspecies of S. enterica were present in this population and were nonrandomly distributed among the lizards. In particular, S. enterica subsp. diarizonae was restricted to lizards living in the most shaded parts of the study site with an overstorey of Casuarina trees. Experiments undertaken to investigate the survival of S. enterica cells under seminatural conditions revealed that cell survival decreased with increased exposure to elevated temperatures and UV light. Among the three S. enterica subspecies tested, S. enterica subsp. diarizonae consistently had an average expected life span that was shorter than that observed for the other two subspecies. There was no indication in the data that there was any competitive dominance hierarchy among the S. enterica subspecies within individual hosts. Thus, the nonrandom distribution of S. enterica subspecies in this population of lizards appears to be driven by their different survival characteristics in the external environment. PMID:26092451

  11. A MULTIPLEX PCR METHOD FOR THE RAPID SEROTYPING OF COMMON CLINICAL ISOLATES OF SALMONELLA ENTERICA SUBSPECIES ENTERICA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: The bacterial species Salmonella enterica is one of the major causes of gastroenteritis in humans and has over 1,500 serotypes. Serotyping is the most common tool used to identify isolates from diseased patients. However, the serotyping method can take several weeks and sometimes can ...

  12. Subtyping of Salmonella enterica Subspecies I Using Single-Nucleotide Polymorphisms in Adenylate Cyclase.

    PubMed

    Guard, Jean; Abdo, Zaid; Byers, Sara Overstreet; Kriebel, Patrick; Rothrock, Michael J

    2016-07-01

    Methods to rapidly identify serotypes of Salmonella enterica subspecies I are of vital importance for protecting the safety of food. To supplement the serotyping method dkgB-linked intergenic sequence ribotyping (ISR), single-nucleotide polymorphisms were characterized within adenylate cyclase (cyaA). The National Center for Biotechnology Information (NCBI) database had 378 cyaA sequences from S. enterica subspecies I, which included 42 unique DNA sequences and 19 different amino acid sequences. Five representative isolates, namely serotypes Typhimurium, Kentucky, Enteritidis phage type PT4, and two variants of Enteritidis phage type PT13a, were differentiated within a microsphere-based fluidics system in cyaA by allele-specific primer extension. Validation against 25 poultry-related environmental Salmonella isolates representing 11 serotypes yielded a ∼89% success rate at identifying the serotype of the isolate, and a different region could be targeted to achieve 100%. When coupled with ISR, all serotypes were differentiated. Phage lineages of serotype Enteritidis 13a and 4 were identified, and a biofilm-forming strain of PT13a was differentiated from a smooth phenotype within phage type. Comparative ranking of mutation indices to genes such as the tRNA transferases, the diguanylate cyclases, and genes used for multilocus sequence typing indicated that cyaA is an appropriate gene for assessing epidemiological trends of Salmonella because of its relative stability in nucleotide composition. PMID:27035032

  13. Subtyping of Salmonella enterica Subspecies I Using Single-Nucleotide Polymorphisms in Adenylate Cyclase

    PubMed Central

    Abdo, Zaid; Byers, Sara Overstreet; Kriebel, Patrick; Rothrock, Michael J.

    2016-01-01

    Abstract Methods to rapidly identify serotypes of Salmonella enterica subspecies I are of vital importance for protecting the safety of food. To supplement the serotyping method dkgB-linked intergenic sequence ribotyping (ISR), single-nucleotide polymorphisms were characterized within adenylate cyclase (cyaA). The National Center for Biotechnology Information (NCBI) database had 378 cyaA sequences from S. enterica subspecies I, which included 42 unique DNA sequences and 19 different amino acid sequences. Five representative isolates, namely serotypes Typhimurium, Kentucky, Enteritidis phage type PT4, and two variants of Enteritidis phage type PT13a, were differentiated within a microsphere-based fluidics system in cyaA by allele-specific primer extension. Validation against 25 poultry-related environmental Salmonella isolates representing 11 serotypes yielded a ∼89% success rate at identifying the serotype of the isolate, and a different region could be targeted to achieve 100%. When coupled with ISR, all serotypes were differentiated. Phage lineages of serotype Enteritidis 13a and 4 were identified, and a biofilm-forming strain of PT13a was differentiated from a smooth phenotype within phage type. Comparative ranking of mutation indices to genes such as the tRNA transferases, the diguanylate cyclases, and genes used for multilocus sequence typing indicated that cyaA is an appropriate gene for assessing epidemiological trends of Salmonella because of its relative stability in nucleotide composition. PMID:27035032

  14. Profile of Salmonella enterica subsp. enterica (Subspecies I) Serotype 4,5,12:i:− Strains Causing Food-Borne Infections in New York City

    PubMed Central

    Agasan, Alice; Kornblum, John; Williams, George; Pratt, Chi-Chi; Fleckenstein, Phylis; Wong, Marie; Ramon, Alex

    2002-01-01

    Strains of newly emerging Salmonella enterica subsp. enterica (subspecies I) serotype 4,5,12:i:− causing food-borne infections, including a large food poisoning outbreak (n = 86) characterized by persistent diarrhea (14% bloody), abdominal pain, fever, and headache, were examined. The organisms were found in the stool samples from the patients. The biochemical profile of the organisms is consistent with that of S. enterica subsp. I serotypes, except for decreased dulcitol (13%) and increased inositol (96%) utilization. Twenty-eight percent of the strains showed resistance to streptomycin, sulfonamides, or tetracycline only; all three antimicrobial agents; or these agents either alone or in combination with ampicillin, trimethoprim, and trimethoprim-sulfamethoxazole. None of the serotype 4,5,12:i:− strains showed resistance or decreased susceptibility to chloramphenicol or ciprofloxacin. On pulsed-field gel electrophoresis (PFGE), the strains showed 11 or 12 resolvable genomic fragments with 18 banding patterns and three PFGE profile (PFP) clusters (i.e., PFP/A, PFP/B, and PFP/C). Seventy-five percent of the isolates fingerprinted were closely related (zero to three band differences; similarity [Dice] coefficient, 86 to 100%); 63% of these were indistinguishable from each other (PFP/A1). PFP/A1 was common to all strains from the outbreak and 11 hospital sources. Strains from six other hospitals shared clusters PFP/B and PFP/C. PFP/C4, of the environmental isolate, was unrelated to PFP/A and PFP/B. Nine band differences (similarity coefficient, 61%) were noted between PFP/A1 and PFP/E of the multidrug-resistant S. enterica subsp. enterica serotype Typhimurium definitive type 104 strains. Whether these emerging Salmonella strains represent a monophasic, Dul− variant of serotype Typhimurium or S. enterica subsp. enterica serotype Lagos or a distinct serotype of S. enterica subsp. I is not yet known. Some of the phenotypic and genotypic properties of the serotype

  15. Biofilm Formation and Morphotypes of Salmonella enterica subsp.arizonae Differs from Those of Other Salmonella enterica Subspecies in Isolates from Poultry Houses.

    PubMed

    Lamas, A; Fernandez-No, I C; Miranda, J M; Vázquez, B; Cepeda, A; Franco, C M

    2016-07-01

    Salmonella serovars are responsible for foodborne diseases around the world. The ability to form biofilms allows microorganisms to survive in the environment. In this study, 73 Salmonella strains, belonging to four different subspecies, were isolated from poultry houses and foodstuffs and tested. Biofilm formation was measured at four different temperatures and two nutrient concentrations. Morphotypes and cellulose production were evaluated at three different temperatures. The presence of several genes related to biofilm production was also examined. All strains and subspecies of Salmonella had the ability to form biofilms, and 46.57% of strains produced biofilms under all conditions tested. Biofilm formation was strain dependent and varied according to the conditions. This is the first study to analyze biofilm formation in a wide number of Salmonella enterica subsp. arizonae strains, and no direct relationship between the high prevalence of Salmonella enterica subsp. arizonae strains and their ability to form biofilm was established. Morphotypes and cellulose production varied as the temperature changed, with 20°C being the optimum temperature for expression of the red, dry, and rough morphotype and cellulose. Salmonella enterica subsp. arizonae, whose morphotype is poorly studied, only showed a smooth and white morphotype and lacked the csgD and gcpA genes that are implicated in biofilm production. Thus, Salmonella biofilm formation under different environmental conditions is a public health problem because it can survive and advance through the food chain to reach the consumer. PMID:27357031

  16. Salmonella enterica.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian Salmonella infections are important as both a cause of clinical disease in poultry and as a source of food-borne transmission of disease to humans. Host-adapted salmonellae (Salmonella enterica serovar Pullorum and Gallinarum) are responsible for severe systemic diseases, whereas numerous sero...

  17. Resistance phenotypes and genotypes among multiple-antimicrobial-resistant Salmonella enterica subspecies enterica serovar Choleraesuis strains isolated between 2008 and 2012 from slaughter pigs in Okinawa Prefecture, Japan

    PubMed Central

    MATAYOSHI, Masanao; KITANO, Takashi; SASAKI, Tetsu; NAKAMURA, Masaji

    2015-01-01

    A total of 349 Salmonella enterica subspecies enterica serovar Choleraesuis (S. Choleraesuis) strains, which were isolated between 2008 and 2012 from 349 pigs at two slaughterhouses in Okinawa Prefecture, Japan, were investigated for antimicrobial susceptibility and the presence of antimicrobial resistance genes. All isolates were resistant to at least four antimicrobial agents. The antimicrobial agents for which isolates showed a high incidence of resistance were as follows: ampicillin (100%) and streptomycin (100%), followed by gentamicin (99.7%), oxytetracycline (99.7%), sulfamethoxazole/trimethoprim (99.4%), nalidixic acid (40.1%) and oxolinic acid (40.1%). All isolates were sensitive to cefuroxime, ceftiofur, colistin, fosfomycin, enrofloxacin, orbifloxacin and danofloxacin. The predominant resistance phenotypes and genotypes were: resistance to ampicillin, streptomycin, gentamicin, oxytetracycline and sulfamethoxazole/trimethoprim (58.5%, 204/349) and blaTEM-strA-strB-aadA1-aadA2-aacC2-tet (B)-sul1-sul2-dhfrXII-dhfrXIII (36.1%, 126/349). The quinolone resistance-determining regions (QRDRs) of gyrA, gyrB, parC and parE of the quinolone-resistant isolates (n=12) showed amino acid substitutions of Ser-83→Phe or Asp-87→Tyr in GyrA and Ser-107→Ala in ParC. To our knowledge, this is the first report on the molecular characterization of antimicrobial resistance among S. Choleraesuis strains in Japan. PMID:25715779

  18. Molecular typing by random amplification of polymorphic DNA (RAPD) and detection of virulence genes of Salmonella enterica subspecies enterica serovar Gallinarum biovar gallinarum.

    PubMed

    Jin, Ji-Dong; Lee, Dong-Seok; Shin, Eun-Kyung; Kim, Sun-Joong; Jung, Rose; Hahn, Tae-Wook

    2006-12-01

    Salmonella enterica subspecies enterica serovar Gallinarum biovar Gallinarum is the causative agent of fowl typhoid in chickens, outbreaks of which have devastated poultry populations in Korea since 1992. In order to identify genetic differences among S. Gallinarum isolates, bacteria were examined using the random amplified polymorphic DNA (RAPD) method. Of 13 arbitrary primers screened initially, the primer designated as universal rice primer-6 (URP-6) was selected for subsequent typing assays because it produced a distinctive and reproducible DNA fingerprint for a S. Gallinarum reference strain. URP-6-based RAPD analysis assigned 30 S. Gallinarum isolates into 6 types, with 26 isolates (86.6%) belonging to 2 major RAPD types. The distribution of virulence genes in S. Gallinarum isolates was examined by Southern hybridization. All tested isolates had the invasion gene, invA, the virulence plasmid gene, spvB, and the S. Enteritidis fimbrial gene, sefC. The distribution of virulence genes among S. Gallinarum isolates did not correlate with any specific RAPD type. PMID:17213701

  19. Evaluation of vaccine candidate potential of deltaaroA, deltahtrA and deltaaroAdeltahtrA mutants of Salmonella enterica subspecies enterica serovar Abortusequi in guinea pigs.

    PubMed

    Singh, Bhoj Raj; Chandra, Mudit; Hansda, Dhananjoy; Alam, Javed; Babu, Narayanan; Siddiqui, Mehtab Z; Agrawal, Ravi K; Sharma, Gautam

    2013-04-01

    Salmonella enterica subspecies enterica serovar Abortusequi (S. Abortusequi), a host adapted Salmonella causes abortions, still births and foal mortality in equids. Though known since more than 100 years, it is still a problem in many of the developing countries including India. There is dearth of really good vaccine affording immunity lasting at least for one full gestation. In search of a potential vaccine candidate, three defined deletion mutants (deltaaroA, deltahtrA and deltaaroAdeltahtrA) of S. Abortusequi were tested in guinea pig model for attenuation, safety, immunogenicity, humoral immune response, protective efficacy and persistence in host. The deltahtrA and deltaaroAdeltahtrA mutants were found to be safe on oral inoculation in doses as high as 4.2 x 10(9) cfu/animal. Also through subcutaneous inoculation deltaaroAdeltahtrA mutant did not induce any abortion in pregnant guinea pigs. All the three mutants did not induce any illness or death in 1-2 week-old baby guinea pigs except deltahtrA mutant which caused mortality on intraperitoneal inoculation. Inoculation with mutants protected against challenge and increased breeding efficiency of guinea pigs. After >4.5 months of mutant inoculation, guinea pigs were protected against abortifacient dose of wild type S. Abortusequi and mother guinea pigs also conferred resistance to their babies to the similar challenge. Early humoral immune response of S. Abortusequi mutants was characteristic. Faecal excretion of deltaaroA and htrA mutants was detected up to 45 days of inoculation in guinea pigs while deltaaroAdeltahtrA mutant could not be detected after 21 days of inoculation. The results indicated that the double deletion mutant (deltaaroAdeltahtrA) was the most effective and safe candidate for vaccination against S. Abortusequi through mucosal route of inoculation. PMID:24195347

  20. Bacteriophage-encoded type III effectors in Salmonella enterica subspecies 1 serovar Typhimurium.

    PubMed

    Ehrbar, Kristin; Hardt, Wolf-Dietrich

    2005-01-01

    Salmonella spp. are Gram-negative bacteria which cause infections ranging from mild, self-limiting enterocolitis to systemic (typhoid) disease. Recent work has established that the genetic makeup varies considerably between different Salmonella strains. Phages play an important role in this diversity. In fact, Salmonella has emerged as a prime example for the involvement of virulence factor encoding phages in the emergence of new epidemic strains. Among other virulence factors, Salmonella enterica utilizes two specialized protein secretion systems termed type III secretion systems (TTSS) to deliver effector proteins into host cells which manipulate host cell signaling cascades. These two TTSS and several effectors are encoded within Salmonella pathogenicity islands 1 and 2. Some effectors including SopE, SspH1, SseI and SopE2 are encoded by phages or phage remnants. These phage-encoded effectors seem to be transferred between different Salmonella strains. They have attracted much interest because they might contribute to the evolution of Salmonella spp. Here we will focus on SopEPhi which encodes the SPI-1 effector SopE. It provides an excellent example to illustrate how horizontally transferred effector proteins are integrated into the complex regulatory network of a TTSS in a recipient bacterium. Additional data supporting the hypothesis are presented. This is a prerequisite to allow optimization of the bacterium host cell interaction by reassortment of the phage-encoded effector protein repertoire. PMID:15567133

  1. Induction of the carrier state in pigeons infected with Salmonella enterica subspecies enterica serovar typhimurium PT99 by treatment with florfenicol: a matter of pharmacokinetics.

    PubMed

    Pasmans, Frank; Baert, Kris; Martel, An; Bousquet-Melou, Alain; Lanckriet, Ruben; De Boever, Sandra; Van Immerseel, Filip; Eeckhaut, Venessa; de Backer, Patrick; Haesebrouck, Freddy

    2008-03-01

    Paratyphoid caused by Salmonella enterica subsp. enterica serovar Typhimurium is the main bacterial disease in pigeons. The ability of Salmonella serovar Typhimurium to persist intracellularly inside pigeon macrophages results in the development of chronic carriers, which maintain the infection in the flock. In this study, the effect of drinking-water medication with florfenicol on Salmonella infection in pigeons was examined. The pharmacokinetics of florfenicol in pigeons revealed a relatively high volume of distribution of 2.02 liters/kg of body weight and maximum concentrations in plasma higher than the MICs for the Salmonella strain used (4 microg/ml) but quick clearance of florfenicol due to a short half-life of 1.73 h. Together with highly variable bioavailability and erratic drinking-water uptake, these parameters resulted in the inability to reach a steady-state concentration through the continuous administration of florfenicol in the drinking water. Florfenicol was capable of reducing only moderately the number of intracellular salmonellae in infected pigeon macrophages in vitro. Only at high extracellular concentrations (>16 microg/ml) was a more-than-10-fold reduction of the number of intracellular bacteria noticed. Florfenicol treatment of pigeons via the drinking water from 2 days after experimental inoculation with Salmonella serovar Typhimurium until euthanasia at 16 days postinoculation resulted in a reduction of Salmonella shedding and an improvement in the fecal consistency. However, internal organs in florfenicol-treated pigeons were significantly more heavily colonized than those in untreated pigeons. In conclusion, the oral application of florfenicol for the treatment of pigeon paratyphoid contributes to the development of carrier animals through sub-MIC concentrations in plasma that do not inhibit intracellular persistency. PMID:18180355

  2. Induction of the Carrier State in Pigeons Infected with Salmonella enterica Subspecies enterica Serovar Typhimurium PT99 by Treatment with Florfenicol: a Matter of Pharmacokinetics▿

    PubMed Central

    Pasmans, Frank; Baert, Kris; Martel, An; Bousquet-Melou, Alain; Lanckriet, Ruben; De Boever, Sandra; Van Immerseel, Filip; Eeckhaut, Venessa; de Backer, Patrick; Haesebrouck, Freddy

    2008-01-01

    Paratyphoid caused by Salmonella enterica subsp. enterica serovar Typhimurium is the main bacterial disease in pigeons. The ability of Salmonella serovar Typhimurium to persist intracellularly inside pigeon macrophages results in the development of chronic carriers, which maintain the infection in the flock. In this study, the effect of drinking-water medication with florfenicol on Salmonella infection in pigeons was examined. The pharmacokinetics of florfenicol in pigeons revealed a relatively high volume of distribution of 2.02 liters/kg of body weight and maximum concentrations in plasma higher than the MICs for the Salmonella strain used (4 μg/ml) but quick clearance of florfenicol due to a short half-life of 1.73 h. Together with highly variable bioavailability and erratic drinking-water uptake, these parameters resulted in the inability to reach a steady-state concentration through the continuous administration of florfenicol in the drinking water. Florfenicol was capable of reducing only moderately the number of intracellular salmonellae in infected pigeon macrophages in vitro. Only at high extracellular concentrations (>16 μg/ml) was a more-than-10-fold reduction of the number of intracellular bacteria noticed. Florfenicol treatment of pigeons via the drinking water from 2 days after experimental inoculation with Salmonella serovar Typhimurium until euthanasia at 16 days postinoculation resulted in a reduction of Salmonella shedding and an improvement in the fecal consistency. However, internal organs in florfenicol-treated pigeons were significantly more heavily colonized than those in untreated pigeons. In conclusion, the oral application of florfenicol for the treatment of pigeon paratyphoid contributes to the development of carrier animals through sub-MIC concentrations in plasma that do not inhibit intracellular persistency. PMID:18180355

  3. Molecular fingerprinting of Salmonella enterica subsp. enterica Typhimurium and Salmonella enterica subsp. enterica derby isolated from tropical seafood in South India.

    PubMed

    Kumar, Rakesh; Surendran, P K; Thampuran, Nirmala

    2008-09-01

    Salmonella enterica subsp. enterica Typhimurium and Salmonella enterica subsp. enterica Derby strains isolated from different seafood were genotyped by PCR-ribotyping and ERIC-PCR assays. This study has ascertained the genetic relatedness among serovars prevalent in tropical seafood. PCR-ribotyping exhibited genetic variation in both Salmonella serovars, and ribotype profile (II) was most predominant, which was observed in 10/18 of Salmonella enterica subsp. enterica Typhimurium and 7/17 Salmonella enterica subsp. enterica Derby isolates. Cluster analysis of ERIC-PCR for Salmonella enterica subsp. enterica Typhimurium strains exhibited nine different banding patterns and four strains showed >95% genetic homology within the cluster pairs. ERIC-PCR produced more genetic variations in Salmonella enterica subsp. enterica Typhimurium; nevertheless, both methods were found to be comparable for Salmonella enterica subsp. enterica Derby isolates. Discrimination index of PCR-ribotyping for Salmonella enterica subsp. enterica Typhimurium isolates was obtained at 0.674 and index value 0.714 was observed for Salmonella enterica subsp. enterica Derby strains. Molecular fingerprinting investigation highlighted the hypothesis of diverse routes of Salmonella contamination in seafood as multiple clones of Salmonella enterica subsp. enterica Typhimurium and Salmonella enterica subsp. enterica Derby were detected in same or different seafood throughout the study period. PMID:18480975

  4. Whole Genome DNA Sequence Analysis of Salmonella subspecies enterica serotype Tennessee obtained from related peanut butter foodborne outbreaks.

    PubMed Central

    Wilson, Mark R.; Brown, Eric; Keys, Chris; Strain, Errol; Luo, Yan; Muruvanda, Tim; Grim, Christopher; Jean-Gilles Beaubrun, Junia; Jarvis, Karen; Ewing, Laura; Gopinath, Gopal; Hanes, Darcy; Allard, Marc W.; Musser, Steven

    2016-01-01

    Establishing an association between possible food sources and clinical isolates requires discriminating the suspected pathogen from an environmental background, and distinguishing it from other closely-related foodborne pathogens. We used whole genome sequencing (WGS) to Salmonella subspecies enterica serotype Tennessee (S. Tennessee) to describe genomic diversity across the serovar as well as among and within outbreak clades of strains associated with contaminated peanut butter. We analyzed 71 isolates of S. Tennessee from disparate food, environmental, and clinical sources and 2 other closely-related Salmonella serovars as outgroups (S. Kentucky and S. Cubana), which were also shot-gun sequenced. A whole genome single nucleotide polymorphism (SNP) analysis was performed using a maximum likelihood approach to infer phylogenetic relationships. Several monophyletic lineages of S. Tennessee with limited SNP variability were identified that recapitulated several food contamination events. S. Tennessee clades were separated from outgroup salmonellae by more than sixteen thousand SNPs. Intra-serovar diversity of S. Tennessee was small compared to the chosen outgroups (1,153 SNPs), suggesting recent divergence of some S. Tennessee clades. Analysis of all 1,153 SNPs structuring an S. Tennessee peanut butter outbreak cluster revealed that isolates from several food, plant, and clinical isolates were very closely related, as they had only a few SNP differences between them. SNP-based cluster analyses linked specific food sources to several clinical S. Tennessee strains isolated in separate contamination events. Environmental and clinical isolates had very similar whole genome sequences; no markers were found that could be used to discriminate between these sources. Finally, we identified SNPs within variable S. Tennessee genes that may be useful markers for the development of rapid surveillance and typing methods, potentially aiding in traceback efforts during future

  5. Draft Genome Sequences of Salmonella enterica subsp. enterica Serovar Berta ATCC 8392 and a Nalidixic Acid-Resistant Isolate of This Strain

    PubMed Central

    Cooper, Ashley; Koziol, Adam G.; Carrillo, Catherine D.

    2016-01-01

    Salmonella enterica subspecies enterica serovar Berta has been isolated in multiple animal species and has been implicated in human disease. Here, we report a 4.7-Mbp draft genome sequence of S. enterica serovar Berta (ATCC strain 8392) and a nalidixic acid-resistant isolate derived from this strain. PMID:27103707

  6. Complete Genome and Methylome Sequences of Salmonella enterica subsp. enterica Serovar Panama (ATCC 7378) and Salmonella enterica subsp. enterica Serovar Sloterdijk (ATCC 15791).

    PubMed

    Yao, Kuan; Muruvanda, Tim; Roberts, Richard J; Payne, Justin; Allard, Marc W; Hoffmann, Maria

    2016-01-01

    Salmonella enterica spp. are pathogenic bacteria commonly associated with food-borne outbreaks in human and animals. Salmonella enterica spp. are characterized into more than 2,500 different serotypes, which makes epidemiological surveillance and outbreak control more difficult. In this report, we announce the first complete genome and methylome sequences from two Salmonella type strains associated with food-borne outbreaks, Salmonella enterica subsp. enterica serovar Panama (ATCC 7378) and Salmonella enterica subsp. enterica serovar Sloterdijk (ATCC 15791). PMID:26988049

  7. Complete Genome and Methylome Sequences of Salmonella enterica subsp. enterica Serovar Panama (ATCC 7378) and Salmonella enterica subsp. enterica Serovar Sloterdijk (ATCC 15791)

    PubMed Central

    Yao, Kuan; Muruvanda, Tim; Roberts, Richard J.; Payne, Justin; Allard, Marc W.

    2016-01-01

    Salmonella enterica spp. are pathogenic bacteria commonly associated with food-borne outbreaks in human and animals. Salmonella enterica spp. are characterized into more than 2,500 different serotypes, which makes epidemiological surveillance and outbreak control more difficult. In this report, we announce the first complete genome and methylome sequences from two Salmonella type strains associated with food-borne outbreaks, Salmonella enterica subsp. enterica serovar Panama (ATCC 7378) and Salmonella enterica subsp. enterica serovar Sloterdijk (ATCC 15791). PMID:26988049

  8. Substructure within Salmonella enterica subsp. enterica Isolates from Australian Wildlife▿

    PubMed Central

    Parsons, Sandra K.; Bull, C. Michael; Gordon, David M.

    2011-01-01

    Multilocus sequence typing of 56 Salmonella enterica subsp. enterica strains isolated from Australian wildlife hosts was performed. The results of population assignment algorithms revealed that the 56 strains could be subdivided into two distinct clades. Strains belonging to the two clades were further distinguished phenotypically, genotypically, and with respect to host distribution. PMID:21378038

  9. Draft Genome Sequences of Salmonella enterica subsp. enterica Serovars Typhimurium and Nottingham Isolated from Food Products

    PubMed Central

    Zheng, Jie; Ayers, Sherry; Melka, David C.; Curry, Phillip E.; Payne, Justin S.; Laasri, Anna; Wang, Charles; Hammack, Thomas S.; Brown, Eric W.

    2016-01-01

    A quantitative real-time PCR (qPCR) designed to detect Salmonella enterica subsp. enterica serovar Enteritidis, targeting the sdf gene, generated positive results for S. enterica subsp. enterica serovar Typhimurium (CFSAN033950) and S. enterica subsp. enterica serovar Nottingham (CFSAN006803) isolated from food samples. Both strains show pulsed-field gel electrophoresis (PFGE) patterns distinct from those of S. Enteritidis. Here, we report the genome sequences of these two strains. PMID:27445384

  10. Salmonella enterica Diversity in Central Californian Coastal Waterways

    PubMed Central

    Walters, Sarah P.; González-Escalona, Narjol; Son, Insook; Melka, David C.; Sassoubre, Lauren M.

    2013-01-01

    Salmonella enterica is one of the most important bacterial enteric pathogens worldwide. However, little is known about its distribution and diversity in the environment. The present study explored the diversity of 104 strains of Salmonella enterica isolated over 2 years from 12 coastal waterways in central California. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing were used to probe species diversity. Seventy-four PFGE patterns and 38 sequence types (STs) were found, including 18 newly described STs. Nineteen of 25 PFGE patterns were indistinguishable from those of clinical isolates in PulseNet. The most common ST was consistent with S. enterica serovar Typhimurium, and other frequently detected STs were associated with the serovars Heidelberg and Enteritidis; all of these serovars are important etiologies of salmonellosis. An investigation into S. enterica biogeography was conducted at the level of ST and subspecies. At the ST and subspecies level, we found a taxon-time relationship but no taxon-area or taxon-environmental distance relationships. STs collected during wet versus dry conditions tended to be more similar; however, STs collected from waterways adjacent to watersheds with similar land covers did not tend to be similar. The results suggest that the lack of dispersal limitation may be an important factor affecting the diversity of S. enterica in the region. PMID:23624479

  11. Complete Genome and Methylome Sequences of Two Salmonella enterica spp.

    PubMed Central

    Yao, Kuan; Muruvanda, Tim; Roberts, Richard J.; Payne, Justin; Allard, Marc W.

    2016-01-01

    Salmonella enterica is responsible for major foodborne outbreaks worldwide. It can cause gastroenteritis characterized by diarrhea, vomiting, and fever. Salmonella infections raise public health concerns along with consequential economic impacts. In this report, we announce the first complete genome sequences of Salmonella enterica subsp. enterica serovar Choleraeuis (S. Choleraeuis) ATCC 10708 and Salmonella enterica subsp. enterica serovar Pullorum (S. Pullorum) ATCC 9120, isolated from patients with diarrhea. PMID:26798102

  12. Whole-genome sequencing of Salmonella enterica subsp. enterica serovar Cubana strains isolated from agricultural sources

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report draft genomes of Salmonella enterica subsp. enterica Serovar Cubana strain CVM42234 isolated from chick feed in 2012 and Salmonella Cubana strain 76814 isolated from swine in 2004. The genome sizes are 4,975,046 and 4,936,251 base pairs, respectively....

  13. Complete Genome Sequence and Methylome of Salmonella enterica subsp. enterica Cerro, a Frequent Dairy Cow Serovar

    PubMed Central

    Haley, Bradd J.; Pirone, Cary; Muruvanda, Tim; Brown, Eric; Allard, Marc; Karns, Jeffrey S.

    2016-01-01

    Salmonella enterica subsp. enterica serovar Cerro is an infrequent pathogen of humans and other mammals but is frequently isolated from the hindgut of asymptomatic cattle in the United States. To further understand the genomic determinants of S. Cerro specificity for the bovine hindgut, the genome of isolate CFSAN001588 was fully sequenced and deposited in the GenBank database. PMID:26823571

  14. Whole-Genome Sequencing of Salmonella enterica subsp. enterica Serovar Ouakam Isolated from Ground Turkey

    PubMed Central

    Marasini, Daya; Abo-Shama, Usama H.

    2016-01-01

    In this report, we announce the first whole-genome sequencing of Salmonella enterica subsp. enterica serovar Ouakam strain GNT-01, isolated from ground turkey retail meat. The strain has a chromosome of 5,088,451 bp long, with a G+C content of 52.3%, and a plasmid of 109,715 bp. PMID:26798110

  15. Draft Genome Sequence of Salmonella enterica subsp. enterica Serovar Mishmarhaemek Isolated from Bovine Feces

    PubMed Central

    Cooper, Ashley; Lambert, Dominic; Koziol, Adam G.; Seyer, Karine

    2015-01-01

    Salmonella enterica subsp. enterica serovar Mishmarhaemek is a Gram-negative, non-spore-forming, rod-shaped bacterium implicated in human clinical disease. Here, we report a 4.8-Mbp draft genome sequence of a nalidixic acid-resistant isolate of S. serovar Mishmarhaemek. PMID:26472847

  16. Complete genome sequence of salmonella enterica subsp. enterica Serovar Thompson Strain RM6836

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica serovar Thompson (S. Thompson) strain RM6836 was isolated from lettuce in 2002. We report the complete sequence and annotation of the genome of S. Thompson strain RM6836. This is the first reported complete genome sequence for S. Thompson and will provide a point ...

  17. Draft Genome Sequence of Salmonella enterica subsp. enterica Serotype Saintpaul Strain S-70, Isolated from an Aquatic Environment

    PubMed Central

    Estrada-Acosta, Mitzi; Medrano-Félix, Andrés; Jiménez, Maribel; Gómez-Gil, Bruno; León-Félix, Josefina; Amarillas, Luis

    2013-01-01

    Salmonella is a pathogen of worldwide importance, causing disease in a vast range of hosts, including humans. We report the genome sequence of Salmonella enterica subsp. enterica serotype Saintpaul strain S-70, isolated from an aquatic environment. PMID:24336367

  18. Complete and Closed Genome Sequences of 10 Salmonella enterica subsp. enterica Serovar Anatum Isolates from Human and Bovine Sources

    PubMed Central

    Nguyen, Scott V.; Bono, James L.; Smith, Timothy P. L.; Fields, Patricia I.; Dinsmore, Blake A.; Santovenia, Monica; Kelley, Christy M.; Wang, Rong; Bosilevac, Joseph M.; Harhay, Gregory P.

    2016-01-01

    Salmonella enterica is an important pathogen transmitted by numerous vectors. Genomic comparisons of Salmonella strains from disparate hosts have the potential to further our understanding of mechanisms underlying host specificities and virulence. Here, we present the closed genome and plasmid sequences of 10 Salmonella enterica subsp. enterica serovar Anatum isolates from bovine and human sources. PMID:27257192

  19. Complete and Closed Genome Sequences of 10 Salmonella enterica subsp. enterica Serovar Anatum Isolates from Human and Bovine Sources.

    PubMed

    Nguyen, Scott V; Harhay, Dayna M; Bono, James L; Smith, Timothy P L; Fields, Patricia I; Dinsmore, Blake A; Santovenia, Monica; Kelley, Christy M; Wang, Rong; Bosilevac, Joseph M; Harhay, Gregory P

    2016-01-01

    Salmonella enterica is an important pathogen transmitted by numerous vectors. Genomic comparisons of Salmonella strains from disparate hosts have the potential to further our understanding of mechanisms underlying host specificities and virulence. Here, we present the closed genome and plasmid sequences of 10 Salmonella enterica subsp. enterica serovar Anatum isolates from bovine and human sources. PMID:27257192

  20. Complete Genome Sequences of Two Outbreak Strains of Salmonella enterica subsp. enterica Serovar Thompson Associated with Cilantro

    PubMed Central

    Huynh, Steven; Gorski, Lisa; Cooper, Kerry K.; Miller, William G.

    2015-01-01

    Salmonella enterica subsp. enterica serovar Thompson strains RM1984 (CADPH-99A2334) and RM1986 (CADPH-99A2345) are associated with a 1999 outbreak in contaminated cilantro. We report here the complete genome sequences and annotation of these two S. Thompson strains. These genomes are distinct and provide additional data for our understanding of S. enterica. PMID:26586897

  1. Complete Genome Sequences of Two Outbreak Strains of Salmonella enterica subsp. enterica Serovar Thompson Associated with Cilantro.

    PubMed

    Parker, Craig T; Huynh, Steven; Gorski, Lisa; Cooper, Kerry K; Miller, William G

    2015-01-01

    Salmonella enterica subsp. enterica serovar Thompson strains RM1984 (CADPH-99A2334) and RM1986 (CADPH-99A2345) are associated with a 1999 outbreak in contaminated cilantro. We report here the complete genome sequences and annotation of these two S. Thompson strains. These genomes are distinct and provide additional data for our understanding of S. enterica. PMID:26586897

  2. Rapid detection of Salmonella enterica with primers specific for iroB.

    PubMed Central

    Bäumler, A J; Heffron, F; Reissbrodt, R

    1997-01-01

    The iroB gene of Salmonella enterica is absent from the chromosome of the related organism Escherichia coli. We determined the distribution of this gene among 150 bacterial isolates, representing 51 serotypes of different Salmonella species and subspecies and 8 other bacterial species which are frequent contaminants during routine enrichment procedures by Southern hybridization. An iroB-specific DNA probe detected homologous sequences in all strains of S. enterica, including serotypes of S. enterica subsp. enterica (I), salamae (II), diarizonae (IIIb), and houtenae (IV). No hybridization signal was obtained with strains of Salmonella bongori or other bacterial species. In contrast, hybridization with a DNA probe specific for purD, a purine biosynthesis gene, detected homologs in all bacterial species tested. Primers specific for iroB were used to amplify this gene from 197 bacterial isolates by PCR. The iroB gene could be PCR amplified from S. enterica subsp. enterica (I), salamae (II), diarizonae (IIIb), houtenae (IV), arizonae (IIIa), and indica (VI), but not from S. bongori or other bacterial species. Thus, PCR amplification of iroB can be used to distinguish between S. enterica and other bacterial species, including S. bongori. A combination of preenrichment in buffered peptone water supplemented with ferrioxamine E and amplification of iroB by magnetic immuno-PCR allowed detection of S. enterica in albumen within 24 h. In conclusion, PCR amplification of iroB is a new sensitive and selective method which has the potential to rapidly detect S. enterica serotypes. PMID:9114411

  3. Detection of Salmonella enterica subpopulations by phenotype microarray antibiotic resistance patterns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subspecies I is an important cause of food borne illness. We compared 6 strains of for resistance to 240 antibiotics that were included in a commercially available panel and also compared the strains by a conventional assay that is used to determine clinical resistance. Differen...

  4. First report of iliacus abscess caused by Salmonella enterica serovar Othmarschen.

    PubMed

    Jha, Babita; Kim, Choon-Mee; Kim, Dong-Min; Chung, Jong-Hoon; Yoon, Na-Ra; Jha, Piyush; Kim, Seok Won; Jang, Sook Jin; Kim, Seon Gyeong; Chung, Jae Keun

    2016-02-01

    The non-typhoidal bacterium Salmonella enterica subspecies enterica serovar Othmarschen (Salmonella Othmarschen) is a rare human pathogen. Abscess formation due to non-typhoidal Salmonella infections is a very rare complication in this antibiotic era. We report the first case of iliacus abscess after a short period of gastroenteritis which was caused by non-typhoidal Salmonella enterica belonging to group C1, serovar Othmarschen in a patient without any underlying conditions. A young female presented in our hospital complaining of pain in right hip joint area. She gave a history of watery diarrhea 3 days before the onset of pain. On examination the patient was ill-looking and there was tenderness in the right hip joint area. S. enterica was identified using 16S rRNA gene amplification by PCR and serotyped to be serovar Othmarschen from the pus sample of iliacus abscess. This is the first reported case of iliacus abscess due to Salmonella serover Othmarschen infection. Our case suggests that S. enterica serovar Othmarschen can cause severe focal infections associated with gastroenteritis. The literature on the rare association of Salmonella enterica and abscess formation is reviewed. PMID:26482919

  5. Two Draft Genome Sequences of a New Serovar of Salmonella enterica, Serovar Lubbock

    PubMed Central

    den Bakker, Henk C.; Nightingale, Kendra K.; Brichta-Harhay, Dayna M.; Edrington, Thomas S.; Loneragan, Guy H.

    2015-01-01

    Salmonella enterica is principally a foodborne pathogen that shows considerable serovar diversity. In this report, we present two draft genome sequences of Salmonella enterica subsp. enterica serovar Lubbock, a novel serovar. PMID:25883279

  6. Two draft genome sequences of a new serovar of Salmonella enterica, serovar Lubbock

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is principally a foodborne pathogen that shows considerable serovar diversity. In this report, we present two draft genome sequences of Salmonella enterica subsp. enterica serovar Lubbock, a novel serovar....

  7. Muscle Abscess due to Salmonella Enterica

    PubMed Central

    Akkoyunlu, Yasemin; Ceylan, Bahadir; Iraz, Meryem; Elmadag, Nuh Mehmet; Aslan, Turan

    2013-01-01

    Non typhoidal Salmonellae spp. causes clinical symptoms especially in neonates, infants, aged and immunocompromised patients. Hematogenous dissemination may occur in complicated cases whereas the formation of abscess is rare. A 61-year old woman presented to our hospital with pain and a mass in her left arm, without fever and leukocytosis. She was using methotrexate, corticosteroids and quinine for rheumatoid arthritis. She had a history of cervix cancer and was given radiotherapy and chemotherapy 3 years ago. Upon physical examination and magnetic resonance imaging, the mass was considered as an abscess and was surgically drained. Salmonella enterica spp. enterica was yielded in the culture of the drainage material. Ceftriaxon 2g/day was started intramuscularly and continued for 4 weeks. Salmonellosis is usually a self-limited disease, generally restricted to gastrointestinal tract and acquired following food poisoning. Management of Salmonella abscess requires a combination of antibiotherapy, surgical drainage and eradication of primary foci. PMID:24396582

  8. Salmonella enterica Serotype Dublin Infection: an Emerging Infectious Disease for the Northeastern United States

    PubMed Central

    McDonough, Patrick L.; Fogelman, David; Shin, Sang J.; Brunner, Michael A.; Lein, Donald H.

    1999-01-01

    Salmonella enterica subspecies enterica serotype Dublin (S. enterica Dublin) emerged for the first time in New York, Pennsylvania, and Ohio in 1988. Since that time this host-adapted serotype has spread throughout the veal- and dairy beef-raising operations in the region; very few dairy farms have experienced clinical S. enterica Dublin infections. This study details the epidemiology of the outbreaks in cattle. During the period 1988 through 1995, nine New York and four Pennsylvania counties have been affected; 13 different locations were involved in New York, and 10 were involved in Pennsylvania. The morbidity and mortality and seasonal distribution of outbreaks, which totaled 35, is described. The antimicrobial susceptibility pattern of isolates revealed that many of the strains were resistant to a number of commonly used drugs. Clinical case details and pathology information are provided, with a caution to clinicians and microbiologists presented with suspect animals, i.e., most cases occurred in older calves, which is atypical for salmonellosis for this region (calves were 8 or more weeks old) and presented as pneumonia and septicemia rather than the primarily diarrheal syndrome that is more typically recognized for the region. The epidemiology of cases is analyzed through cluster analysis of bacterial isolates and their fatty acid methyl ester profiles; at least six clones appeared in the region during the study period. Results of the epidemiology analysis are used to support a hypothesis regarding the source of S. enterica Dublin for the region and its manner of dissemination. PMID:10405378

  9. Phylogenetic Diversity of the Enteric Pathogen Salmonella enterica subsp. enterica Inferred from Genome-Wide Reference-Free SNP Characters

    PubMed Central

    Timme, Ruth E.; Pettengill, James B.; Allard, Marc W.; Strain, Errol; Barrangou, Rodolphe; Wehnes, Chris; Van Kessel, JoAnn S.; Karns, Jeffrey S.; Musser, Steven M.; Brown, Eric W.

    2013-01-01

    The enteric pathogen Salmonella enterica is one of the leading causes of foodborne illness in the world. The species is extremely diverse, containing more than 2,500 named serovars that are designated for their unique antigen characters and pathogenicity profiles—some are known to be virulent pathogens, while others are not. Questions regarding the evolution of pathogenicity, significance of antigen characters, diversity of clustered regularly interspaced short palindromic repeat (CRISPR) loci, among others, will remain elusive until a strong evolutionary framework is established. We present the first large-scale S. enterica subsp. enterica phylogeny inferred from a new reference-free k-mer approach of gathering single nucleotide polymorphisms (SNPs) from whole genomes. The phylogeny of 156 isolates representing 78 serovars (102 were newly sequenced) reveals two major lineages, each with many strongly supported sublineages. One of these lineages is the S. Typhi group; well nested within the phylogeny. Lineage-through-time analyses suggest there have been two instances of accelerated rates of diversification within the subspecies. We also found that antigen characters and CRISPR loci reveal different evolutionary patterns than that of the phylogeny, suggesting that a horizontal gene transfer or possibly a shared environmental acquisition might have influenced the present character distribution. Our study also shows the ability to extract reference-free SNPs from a large set of genomes and then to use these SNPs for phylogenetic reconstruction. This automated, annotation-free approach is an important step forward for bacterial disease tracking and in efficiently elucidating the evolutionary history of highly clonal organisms. PMID:24158624

  10. Transmission and retention of Salmonella enterica by phytophagous hemipteran insects.

    PubMed

    Soto-Arias, José Pablo; Groves, Russell L; Barak, Jeri D

    2014-09-01

    Several pest insects of human and livestock habitations are known as vectors of Salmonella enterica; however, the role of plant-feeding insects as vectors of S. enterica to agricultural crops remains unexamined. Using a hemipteran insect pest-lettuce system, we investigated the potential for transmission and retention of S. enterica. Specifically, Macrosteles quadrilineatus and Myzus persicae insects were fed S. enterica-inoculated lettuce leaf discs or artificial liquid diets confined in Parafilm sachets to allow physical contact or exclusively oral ingestion of the pathogen, respectively. After a 24-h acquisition access period, insects were moved onto two consecutive noninoculated leaf discs or liquid diets and allowed a 24-h inoculation access period on each of the two discs or sachets. Similar proportions of individuals from both species ingested S. enterica after a 24-h acquisition access period from inoculated leaf discs, but a significantly higher proportion of M. quadrilineatus retained the pathogen internally after a 48-h inoculation access period. S. enterica was also recovered from the honeydew of both species. After a 48-h inoculation access period, bacteria were recovered from a significantly higher proportion of honeydew samples from M. quadrilineatus than from M. persicae insects. The recovery of S. enterica from leaf discs and liquid diets postfeeding demonstrated that both species of insects were capable of transmitting the bacteria in ways that are not limited to mechanical transmission. Overall, these results suggest that phytophagous insects may serve as potential vectors of S. enterica in association with plants. PMID:24973069

  11. Transmission and Retention of Salmonella enterica by Phytophagous Hemipteran Insects

    PubMed Central

    Soto-Arias, José Pablo; Groves, Russell L.

    2014-01-01

    Several pest insects of human and livestock habitations are known as vectors of Salmonella enterica; however, the role of plant-feeding insects as vectors of S. enterica to agricultural crops remains unexamined. Using a hemipteran insect pest-lettuce system, we investigated the potential for transmission and retention of S. enterica. Specifically, Macrosteles quadrilineatus and Myzus persicae insects were fed S. enterica-inoculated lettuce leaf discs or artificial liquid diets confined in Parafilm sachets to allow physical contact or exclusively oral ingestion of the pathogen, respectively. After a 24-h acquisition access period, insects were moved onto two consecutive noninoculated leaf discs or liquid diets and allowed a 24-h inoculation access period on each of the two discs or sachets. Similar proportions of individuals from both species ingested S. enterica after a 24-h acquisition access period from inoculated leaf discs, but a significantly higher proportion of M. quadrilineatus retained the pathogen internally after a 48-h inoculation access period. S. enterica was also recovered from the honeydew of both species. After a 48-h inoculation access period, bacteria were recovered from a significantly higher proportion of honeydew samples from M. quadrilineatus than from M. persicae insects. The recovery of S. enterica from leaf discs and liquid diets postfeeding demonstrated that both species of insects were capable of transmitting the bacteria in ways that are not limited to mechanical transmission. Overall, these results suggest that phytophagous insects may serve as potential vectors of S. enterica in association with plants. PMID:24973069

  12. Complete genomic sequences of two outbreak strains of Salmonella enterica subsp. enterica serovar Thompson associated with cilantro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica serovar Thompson strains RM1984 (CADPH-99A2334) and RM1986 (CADPH -99A2345) are clinical isolates from 1999, putatively related to an outbreak in California from contaminated cilantro. We report the complete genome sequences and annotation of these two S. Thompson...

  13. Genome Sequences of Salmonella enterica subsp. enterica Serovar Lubbock Strains Isolated from Liver Abscesses of Feedlot Cattle

    PubMed Central

    Amachawadi, Raghavendra G.; Thomas, Milton

    2016-01-01

    The genome sequencing of 13 Salmonella enterica subsp. enterica serovar Lubbock strains isolated from liver abscesses of feedlot cattle is reported here. The availability of these genomes will help to further understand the etiologic role of Salmonella strains in liver abscesses of cattle and will serve as references in microbial trace-back studies to improve food safety. PMID:27151794

  14. The complete genome sequence and methylome of Salmonella enterica subsp. enterica serovar Cerro, a frequent dairy cow strain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica serovar Cerro is an infrequent pathogen of humans and other mammals, but is frequently isolated from the hindgut of asymptomatic cattle in the United States. To further understand the genomic determinants of S. Cerro specificity for the bovine hindgut, the genome ...

  15. Complete Genomic Sequences of Two Outbreak Strains of Salmonella enterica subsp. enterica serovar Thompson Associated with Cilantro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica serovar Thompson strains RM1984 (CADPH-99A2334) and RM1986 (CADPH -99A2345) are clinical isolates from 1999, putatively related to an outbreak in California from contaminated cilantro. We report the complete genome sequences and annotation of these two S. Thompson...

  16. Draft Genome Sequence of Salmonella enterica subsp. enterica Serotype Oranienburg Strain S-76, Isolated from an Aquatic Environment

    PubMed Central

    Medrano-Félix, Andrés; Estrada-Acosta, Mitzi; Jiménez, Maribel; Gómez-Gil, Bruno; León-Félix, Josefina; Amarillas, Luis

    2013-01-01

    Salmonella is a widespread microorganism and a common causative agent of food-borne illnesses. Salmonella enterica subsp. enterica serotype Oranienburg is highly prevalent in surface water from tropical ecosystems and is not commonly related to illnesses. Here, we report the first genome sequence of Salmonella Oranienburg strain S-76, isolated from an aquatic environment. PMID:24336368

  17. Evolutionary relationships between known serotypes and unique variants of Salmonella enterica as determined by ISR secondary structure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Intergenic Sequence Ribotyping (ISR) near the dkgB gene of Salmonella enterica subspecies I genome is now used to assign serotype in a manner that is largely concordant with the historical Kauffman-White-LeMinor (KWL) antibody-based scheme. ISR has a number of advantages over the KWL scheme, and it ...

  18. Complete Genome Sequence of Salmonella enterica subsp. enterica Serovar Typhi Isolate B/SF/13/03/195 Associated with a Typhoid Carrier in Pasir Mas, Kelantan, Malaysia

    PubMed Central

    Sim, Kee-Shin; Mohd Nor, Fauziah; Mat Hussin, Hani; Hamzah, Wan Mansor; Najimudin, Nazalan

    2015-01-01

    We report here the complete genome sequence of Salmonella enterica subsp. enterica serovar Typhi B/SF/13/03/195 obtained from a typhoid carrier, who is a food handler in Pasir Mas, Kelantan. PMID:26564035

  19. Genome Sequence of Salmonella enterica subsp. enterica Serovar Typhi Isolate PM016/13 from Untreated Well Water Associated with a Typhoid Outbreak in Pasir Mas, Kelantan, Malaysia.

    PubMed

    Muhamad Harish, Salwani; Sim, Kee-Shin; Najimudin, Nazalan; Aziah, Ismail

    2015-01-01

    Salmonella enterica subsp. enterica serovar Typhi is a human-restricted pathogen that causes typhoid fever. Even though it is a human-restricted pathogen, the bacterium is also isolated from environments such as groundwater and pond water. Here, we describe the genome sequence of the Salmonella enterica subsp. enterica serovar Typhi PM016/13 which was isolated from well water during a typhoid outbreak in Kelantan, Malaysia, in 2013. PMID:26564032

  20. Genome Sequence of Salmonella enterica subsp. enterica Serovar Typhi Isolate PM016/13 from Untreated Well Water Associated with a Typhoid Outbreak in Pasir Mas, Kelantan, Malaysia

    PubMed Central

    Sim, Kee-Shin; Najimudin, Nazalan

    2015-01-01

    Salmonella enterica subsp. enterica serovar Typhi is a human-restricted pathogen that causes typhoid fever. Even though it is a human-restricted pathogen, the bacterium is also isolated from environments such as groundwater and pond water. Here, we describe the genome sequence of the Salmonella enterica subsp. enterica serovar Typhi PM016/13 which was isolated from well water during a typhoid outbreak in Kelantan, Malaysia, in 2013. PMID:26564032

  1. Comparative genetics of the inv-spa invasion gene complex of Salmonella enterica.

    PubMed

    Boyd, E F; Li, J; Ochman, H; Selander, R K

    1997-03-01

    The chromosomal region containing the Salmonella enterica pathogenic island inv-spa was present in the last common ancestor of all the contemporary lineages of salmonellae. For multiple strains of S. enterica, representing all eight subspecies, nucleotide sequences were obtained for five genes of the inv-spa invasion complex, invH, invE, invA, spaM, and spaN, al of which encode proteins that are required for entry of the bacteria into cultured epithelial cells. The invE, invA, spaM, and spaN genes were present in all eight subspecies of S. enterica, and for invE and invA and their products, levels of sequence variation among strains were within the ranges reported for housekeeping genes. In contrast, the InvH, SpaM, and SpaN proteins were unusually variable in amino acid sequence. Furthermore, invH was absent from the subspecies V isolates examined. The SpaM and SpaN proteins provide further evidence of a relationship (first detected by Li et al. [J. Li, H. Ochman, E. A. Groisman, E. F. Boyd, F. Solomon, K. Nelson, and R. K. Selander, Proc. Natl. Acad. Sci. USA 92:7252-7256, 1995]) between the cellular location of the products of the inv-spa genes and evolutionary rate, as reflected in the level of polymorphism within S. enterica. Invasion proteins that are membrane bound or membrane associated are relatively conserved in amino acid sequence, whereas those that are exported to the extracellular environment are hypervariable, possibly reflecting the action of diversifying selection. PMID:9068645

  2. Interaction of Salmonella enterica with Fresh Produce Leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Attachment and colonization of Salmonella enterica serovars to fresh produce leaves was investigated. Biofilm assay and attachment of Salmonella serovars to intact and cut leaves were determined. Salmonella Tennessee and Salmonella Thompson produced stronger biofilms compared to Salmonella Newpor...

  3. Flagella-independent surface motility in Salmonella enterica serovar Typhimurium

    PubMed Central

    Park, Sun-Yang; Pontes, Mauricio H.; Groisman, Eduardo A.

    2015-01-01

    Flagella are multiprotein complexes necessary for swimming and swarming motility. In Salmonella enterica serovar Typhimurium, flagella-mediated motility is repressed by the PhoP/PhoQ regulatory system. We now report that Salmonella can move on 0.3% agarose media in a flagella-independent manner when experiencing the PhoP/PhoQ-inducing signal low Mg2+. This motility requires the PhoP-activated mgtA, mgtC, and pagM genes, which specify a Mg2+ transporter, an inhibitor of Salmonella’s own F1Fo ATPase, and a small protein of unknown function, respectively. The MgtA and MgtC proteins are necessary for pagM expression because pagM mRNA levels were lower in mgtA and mgtC mutants than in wild-type Salmonella, and also because pagM expression from a heterologous promoter rescued motility in mgtA and mgtC mutants. PagM promotes group motility by a surface protein(s), as a pagM-expressing strain conferred motility upon a pagM null mutant, and proteinase K treatment eliminated motility. The pagM gene is rarely found outside subspecies I of S. enterica and often present in nonfunctional allelic forms in organisms lacking the identified motility. Deletion of the pagM gene reduced bacterial replication on 0.3% agarose low Mg2+ media but not in low Mg2+ liquid media. Our findings define a form of motility that allows Salmonella to scavenge nutrients and to escape toxic compounds in low Mg2+ semisolid environments. PMID:25624475

  4. Flagella-independent surface motility in Salmonella enterica serovar Typhimurium.

    PubMed

    Park, Sun-Yang; Pontes, Mauricio H; Groisman, Eduardo A

    2015-02-10

    Flagella are multiprotein complexes necessary for swimming and swarming motility. In Salmonella enterica serovar Typhimurium, flagella-mediated motility is repressed by the PhoP/PhoQ regulatory system. We now report that Salmonella can move on 0.3% agarose media in a flagella-independent manner when experiencing the PhoP/PhoQ-inducing signal low Mg(2+). This motility requires the PhoP-activated mgtA, mgtC, and pagM genes, which specify a Mg(2+) transporter, an inhibitor of Salmonella's own F1Fo ATPase, and a small protein of unknown function, respectively. The MgtA and MgtC proteins are necessary for pagM expression because pagM mRNA levels were lower in mgtA and mgtC mutants than in wild-type Salmonella, and also because pagM expression from a heterologous promoter rescued motility in mgtA and mgtC mutants. PagM promotes group motility by a surface protein(s), as a pagM-expressing strain conferred motility upon a pagM null mutant, and proteinase K treatment eliminated motility. The pagM gene is rarely found outside subspecies I of S. enterica and often present in nonfunctional allelic forms in organisms lacking the identified motility. Deletion of the pagM gene reduced bacterial replication on 0.3% agarose low Mg(2+) media but not in low Mg(2+) liquid media. Our findings define a form of motility that allows Salmonella to scavenge nutrients and to escape toxic compounds in low Mg(2+) semisolid environments. PMID:25624475

  5. Integrative Analysis of Salmonellosis in Israel Reveals Association of Salmonella enterica Serovar 9,12:l,v:− with Extraintestinal Infections, Dissemination of Endemic S. enterica Serovar Typhimurium DT104 Biotypes, and Severe Underreporting of Outbreaks

    PubMed Central

    Marzel, Alex; Desai, Prerak T.; Nissan, Israel; Schorr, Yosef Ilan; Suez, Jotham; Valinsky, Lea; Reisfeld, Abraham; Agmon, Vered; Guard, Jean; McClelland, Michael

    2014-01-01

    Salmonella enterica is the leading etiologic agent of bacterial food-borne outbreaks worldwide. This ubiquitous species contains more than 2,600 serovars that may differ in their host specificity, clinical manifestations, and epidemiology. To characterize salmonellosis epidemiology in Israel and to study the association of nontyphoidal Salmonella (NTS) serovars with invasive infections, 48,345 Salmonella cases reported and serotyped at the National Salmonella Reference Center between 1995 and 2012 were analyzed. A quasi-Poisson regression was used to identify irregular clusters of illness, and pulsed-field gel electrophoresis in conjunction with whole-genome sequencing was applied to molecularly characterize strains of interest. Three hundred twenty-nine human salmonellosis clusters were identified, representing an annual average of 23 (95% confidence interval [CI], 20 to 26) potential outbreaks. We show that the previously unsequenced S. enterica serovar 9,12:l,v:− belongs to the B clade of Salmonella enterica subspecies enterica, and we show its frequent association with extraintestinal infections, compared to other NTS serovars. Furthermore, we identified the dissemination of two prevalent Salmonella enterica serovar Typhimurium DT104 clones in Israel, which are genetically distinct from other global DT104 isolates. Accumulatively, these findings indicate a severe underreporting of Salmonella outbreaks in Israel and provide insights into the epidemiology and genomics of prevalent serovars, responsible for recurring illness. PMID:24719441

  6. Genomic investigation of Salmonella enterica sequences associated with long-term colonization of the bovine gut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica is a leading cause of food and waterborne infections globally in both humans and livestock with an estimated 93 million annual human infections caused by nontyphoidal S. enterica alone. However, some serotypes within this species are known to cause mild infection...

  7. Diversity of Genome Structure in Salmonella enterica Serovar Typhi Populations†

    PubMed Central

    Kothapalli, Sushma; Nair, Satheesh; Alokam, Suneetha; Pang, Tikki; Khakhria, Rasik; Woodward, David; Johnson, Wendy; Stocker, Bruce A. D.; Sanderson, Kenneth E.; Liu, Shu-Lin

    2005-01-01

    The genomes of most strains of Salmonella and Escherichia coli are highly conserved. In contrast, all 136 wild-type strains of Salmonella enterica serovar Typhi analyzed by partial digestion with I-CeuI (an endonuclease which cuts within the rrn operons) and pulsed-field gel electrophoresis and by PCR have rearrangements due to homologous recombination between the rrn operons leading to inversions and translocations. Recombination between rrn operons in culture is known to be equally frequent in S. enterica serovar Typhi and S. enterica serovar Typhimurium; thus, the recombinants in S. enterica serovar Typhi, but not those in S. enterica serovar Typhimurium, are able to survive in nature. However, even in S. enterica serovar Typhi the need for genome balance and the need for gene dosage impose limits on rearrangements. Of 100 strains of genome types 1 to 6, 72 were only 25.5 kb off genome balance (the relative lengths of the replichores during bidirectional replication from oriC to the termination of replication [Ter]), while 28 strains were less balanced (41 kb off balance), indicating that the survival of the best-balanced strains was greater. In addition, the need for appropriate gene dosage apparently selected against rearrangements which moved genes from their accustomed distance from oriC. Although rearrangements involving the seven rrn operons are very common in S. enterica serovar Typhi, other duplicated regions, such as the 25 IS200 elements, are very rarely involved in rearrangements. Large deletions and insertions in the genome are uncommon, except for deletions of Salmonella pathogenicity island 7 (usually 134 kb) from fragment I-CeuI-G and 40-kb insertions, possibly a prophage, in fragment I-CeuI-E. The phage types were determined, and the origins of the phage types appeared to be independent of the origins of the genome types. PMID:15805510

  8. Salmonella enterica: Survival, Colonization, and Virulence Differences among Serovars

    PubMed Central

    Andino, A.; Hanning, I.

    2015-01-01

    Data indicate that prevalence of specific serovars of Salmonella enterica in human foodborne illness is not correlated with their prevalence in feed. Given that feed is a suboptimal environment for S. enterica, it appears that survival in poultry feed may be an independent factor unrelated to virulence of specific serovars of Salmonella. Additionally, S. enterica serovars appear to have different host specificity and the ability to cause disease in those hosts is also serovar dependent. These differences among the serovars may be related to gene presence or absence and expression levels of those genes. With a better understanding of serovar specificity, mitigation methods can be implemented to control Salmonella at preharvest and postharvest levels. PMID:25664339

  9. Growth kinetics of Salmonella enterica in Hajna tetrathionate broth, Rappaport broth and modified semisolid Rappaport agar

    PubMed Central

    FUJIHARA, Masatoshi; TABUCHI, Hiroyuki; UEGAKI, Kaho

    2015-01-01

    To determine the appropriate method for isolating Salmonella enterica, we compared the growth of S. enterica serovars using three selective enrichment media. S. enterica was more successfully isolated from artificially contaminated fecal samples after enrichment in Hajna tetrathionate broth or modified semisolid Rappaport agar than in Rappaport broth. Since most bacteria (other than motile S. enterica) do not migrate on modified semisolid Rappaport agar, the growth characteristics of S. enterica can be interpreted easily and quickly. Two S. enterica isolates did not migrate on modified semisolid Rappaport agar, but did grow in Hajna tetrathionate broth, which suggests that the combined use of these selective enrichment media is appropriate for isolating S. enterica. PMID:26498402

  10. Internal Colonization of Salmonella enterica Serovar Typhimurium in Tomato Plants

    PubMed Central

    Gu, Ganyu; Hu, Jiahuai; Cevallos-Cevallos, Juan M.; Richardson, Susanna M.; Bartz, Jerry A.; van Bruggen, Ariena H. C.

    2011-01-01

    Several Salmonella enterica outbreaks have been traced back to contaminated tomatoes. In this study, the internalization of S. enterica Typhimurium via tomato leaves was investigated as affected by surfactants and bacterial rdar morphotype, which was reported to be important for the environmental persistence and attachment of Salmonella to plants. Surfactants, especially Silwet L-77, promoted ingress and survival of S. enterica Typhimurium in tomato leaves. In each of two experiments, 84 tomato plants were inoculated two to four times before fruiting with GFP-labeled S. enterica Typhimurium strain MAE110 (with rdar morphotype) or MAE119 (without rdar). For each inoculation, single leaflets were dipped in 109 CFU/ml Salmonella suspension with Silwet L-77. Inoculated and adjacent leaflets were tested for Salmonella survival for 3 weeks after each inoculation. The surface and pulp of ripe fruits produced on these plants were also examined for Salmonella. Populations of both Salmonella strains in inoculated leaflets decreased during 2 weeks after inoculation but remained unchanged (at about 104 CFU/g) in week 3. Populations of MAE110 were significantly higher (P<0.05) than those of MAE119 from day 3 after inoculation. In the first year, nine fruits collected from one of the 42 MAE119 inoculated plants were positive for S. enterica Typhimurium. In the second year, Salmonella was detected in adjacent non-inoculated leaves of eight tomato plants (five inoculated with strain MAE110). The pulp of 12 fruits from two plants inoculated with MAE110 was Salmonella positive (about 106 CFU/g). Internalization was confirmed by fluorescence and confocal laser microscopy. For the first time, convincing evidence is presented that S. enterica can move inside tomato plants grown in natural field soil and colonize fruits at high levels without inducing any symptoms, except for a slight reduction in plant growth. PMID:22096553

  11. Colonization and internalization of Salmonella enterica in tomato plants.

    PubMed

    Zheng, Jie; Allard, Sarah; Reynolds, Sara; Millner, Patricia; Arce, Gabriela; Blodgett, Robert J; Brown, Eric W

    2013-04-01

    The consumption of fresh tomatoes has been linked to numerous food-borne outbreaks involving various serovars of Salmonella enterica. Recent advances in our understanding of plant-microbe interactions have shown that human enteric pathogenic bacteria, including S. enterica, are adapted to survive in the plant environment. In this study, tomato plants (Solanum lycopersicum cv. Micro-Tom) grown in sandy loam soil from Virginia's eastern shore (VES) were inoculated with S. enterica serovars to evaluate plausible internalization routes and to determine if there is any niche fitness for certain serovars. Both infested soil and contaminated blossoms can lead to low internal levels of fruit contamination with Salmonella. Salmonella serovars demonstrated a great ability to survive in environments under tomato cultivation, not only in soil but also on different parts of the tomato plant. Of the five serovars investigated, Salmonella enterica serovars Newport and Javiana were dominant in sandy loam soil, while Salmonella enterica serovars Montevideo and Newport were more prevalent on leaves and blossoms. It was also observed that Salmonella enterica serovar Typhimurium had a poor rate of survival in all the plant parts examined here, suggesting that postharvest contamination routes are more likely in S. Typhimurium contamination of tomato fruit. Conversely, S. Newport was the most prevalent serovar recovered in both the tomato rhizosphere and phyllosphere. Plants that were recently transplanted (within 3 days) had an increase in observable internalized bacteria, suggesting that plants were more susceptible to internalization right after transplant. These findings suggest that the particular Salmonella serovar and the growth stage of the plant were important factors for internalization through the root system. PMID:23377940

  12. Colonization and Internalization of Salmonella enterica in Tomato Plants

    PubMed Central

    Allard, Sarah; Reynolds, Sara; Millner, Patricia; Arce, Gabriela; Blodgett, Robert J.; Brown, Eric W.

    2013-01-01

    The consumption of fresh tomatoes has been linked to numerous food-borne outbreaks involving various serovars of Salmonella enterica. Recent advances in our understanding of plant-microbe interactions have shown that human enteric pathogenic bacteria, including S. enterica, are adapted to survive in the plant environment. In this study, tomato plants (Solanum lycopersicum cv. Micro-Tom) grown in sandy loam soil from Virginia's eastern shore (VES) were inoculated with S. enterica serovars to evaluate plausible internalization routes and to determine if there is any niche fitness for certain serovars. Both infested soil and contaminated blossoms can lead to low internal levels of fruit contamination with Salmonella. Salmonella serovars demonstrated a great ability to survive in environments under tomato cultivation, not only in soil but also on different parts of the tomato plant. Of the five serovars investigated, Salmonella enterica serovars Newport and Javiana were dominant in sandy loam soil, while Salmonella enterica serovars Montevideo and Newport were more prevalent on leaves and blossoms. It was also observed that Salmonella enterica serovar Typhimurium had a poor rate of survival in all the plant parts examined here, suggesting that postharvest contamination routes are more likely in S. Typhimurium contamination of tomato fruit. Conversely, S. Newport was the most prevalent serovar recovered in both the tomato rhizosphere and phyllosphere. Plants that were recently transplanted (within 3 days) had an increase in observable internalized bacteria, suggesting that plants were more susceptible to internalization right after transplant. These findings suggest that the particular Salmonella serovar and the growth stage of the plant were important factors for internalization through the root system. PMID:23377940

  13. Plant Pathogen-Induced Water-Soaking Promotes Salmonella enterica Growth on Tomato Leaves

    PubMed Central

    Potnis, Neha; Colee, James; Jones, Jeffrey B.

    2015-01-01

    Plant pathogen infection is a critical factor for the persistence of Salmonella enterica on plants. We investigated the mechanisms responsible for the persistence of S. enterica on diseased tomato plants by using four diverse bacterial spot Xanthomonas species that differ in disease severities. Xanthomonas euvesicatoria and X. gardneri infection fostered S. enterica growth, while X. perforans infection did not induce growth but supported the persistence of S. enterica. X. vesicatoria-infected leaves harbored S. enterica populations similar to those on healthy leaves. Growth of S. enterica was associated with extensive water-soaking and necrosis in X. euvesicatoria- and X. gardneri-infected plants. The contribution of water-soaking to the growth of S. enterica was corroborated by an increased growth of populations on water-saturated leaves in the absence of a plant pathogen. S. enterica aggregates were observed with bacterial spot lesions caused by either X. euvesicatoria or X. vesicatoria; however, more S. enterica aggregates formed on X. euvesicatoria-infected leaves as a result of larger lesion sizes per leaf area and extensive water-soaking. Sparsely distributed lesions caused by X. vesicatoria infection do not support the overall growth of S. enterica or aggregates in areas without lesions or water-soaking; S. enterica was observed as single cells and not aggregates. Thus, pathogen-induced water-soaking and necrosis allow S. enterica to replicate and proliferate on tomato leaves. The finding that the pathogen-induced virulence phenotype affects the fate of S. enterica populations in diseased plants suggests that targeting of plant pathogen disease is important in controlling S. enterica populations on plants. PMID:26386057

  14. Development and application of novel SNP-based serotyping assays in targeting Salmonella enterica within the poultry production and processing continuum.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica serotype Enteriditis (S. Enteriditis) is the leading cause of salmonellosis worldwide. While some S. enterica serotypes are specific to birds, many represent human zoonotic pathogens, thus their presence and survival throughout the continuum of poultry production...

  15. Rapid molecular pathotyping of major salmonella enterica serotypes based on single-nucleotide polymorphisms (SNPs) in the adenylate cyclase (cyaA) gene

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Salmonella enterica subsp. enterica serotype Enteriditis (S. Enteriditis) is the leading cause of salmonellosis worldwide, including the USA. Many S. enterica serotypes known to cause foodborne disease are associated with broiler meat contamination. While some serotypes are specific...

  16. Requirement of siderophore biosynthesis for plant colonization by Salmonella enterica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contaminated fresh produce has become the number one vector of non-typhoidal salmonellosis to humans. However, Salmonella enterica genes essential for the life cycle of this organism outside the mammalian host are for the most part unknown. Screening deletion mutants led to the discovery that an aro...

  17. Limited Genetic Diversity in Salmonella enterica Serovar Enteritidis PT13

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Enteritidis has emerged as a significant food-borne pathogen throughout the world and it is commonly characterized by phage typing (PT). In Canada, PT4, 8 and 13 are the predominant PTs. Epidemiological subtyping of Salmonella is typically done by PFGE but plasmid profil...

  18. Multidrug-Resistant Salmonella enterica Serovar Infantis, Israel

    PubMed Central

    Valinsky, Lea; Weinberger, Miriam; Guy, Sara; Jaffe, Joseph; Schorr, Yosef Ilan; Raisfeld, Abraham; Agmon, Vered; Nissan, Israel

    2010-01-01

    To determine whether rapid emergence of Salmonella enterica serovar Infantis in Israel resulted from an increase in different biotypes or spread of 1 clone, we characterized 87 serovar Infantis isolates on the genotypic and phenotypic levels. The emerging strain comprised 1 genetic clone with a distinct pulsed-field gel electrophoresis profile and a common antimicrobial drug resistance pattern. PMID:21029536

  19. Nationwide pseudo-outbreak of Salmonella enterica ssp. diarizonae, France.

    PubMed

    Thiolet, J M; Jourdan-Da Silva, N; Reggiani, A; De Valk, H; Coignard, B; Weill, F X

    2011-06-01

    To investigate an increased incidence of human cultures growing Salmonella enterica ssp. diarizonae serotype 61:k:1,5,7 in France in 2008, we reviewed medical records of case patients and identified the material used during invasive procedures and for bacterial culture. Trace-back investigations incriminated culture media containing contaminated sheep blood agar. PMID:20718799

  20. Foodborne Outbreak and Nonmotile Salmonella enterica Variant, France

    PubMed Central

    Brisabois, Anne; Accou-Demartin, Marie; Josse, Adeline; Marault, Muriel; Francart, Sylvie; Da Silva, Nathalie Jourdan; Weill, François-Xavier

    2012-01-01

    We report a food-related outbreak of salmonellosis in humans caused by a nonmotile variant of Salmonella enterica serotype Typhimurium in France in 2009. This nonmotile variant had been circulating in laying hens but was not considered as Typhimurium and consequently escaped European poultry flock regulations. PMID:22257550

  1. Regional distribution of two dairy-associated Salmonella enterica serotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is a zoonotic pathogen frequently associated with dairy farms. The organism can cause disease in cows but is also frequently shed in large numbers by dairy cows that are asymptomatic. Cows on a ~100 head dairy farm in Pennsylvania, USA, (focal dairy) were previously shown to have...

  2. Salmonella enterica genomics and genetics of antimicrobial resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is an important food-borne pathogen and an excellent model system for the study of genomics, virulence and pathogenesis. . There are over 2,400 Salmonella serotypes each of which differs in their ability to cause disease in humans and animals, persist within the host, and survive...

  3. Method for the detection of Salmonella enterica serovar Enteritidis

    DOEpatents

    Agron, Peter G.; Andersen, Gary L.; Walker, Richard L.

    2008-10-28

    Described herein is the identification of a novel Salmonella enterica serovar Enteritidis locus that serves as a marker for DNA-based identification of this bacterium. In addition, three primer pairs derived from this locus that may be used in a nucleotide detection method to detect the presence of the bacterium are also disclosed herein.

  4. Limited genetic diversity in Salmonella enterica Serovar Enteritidis PT13

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Enteritidis has emerged as a significant foodborne pathogen throughout the world and is commonly characterized by phage typing. In Canada phage types (PT) 4, 8 and 13 predominate and in 2005 a large foodborne PT13 outbreak occurred in the province of Ontario. The ability ...

  5. Effect of residual sanitizers on Salmonella enterica biofilm formation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Salmonella enterica are a diverse group of bacteria that represent a serious risk to public health. Bacterial attachment on food and contact surfaces can lead to biofilm formation, and once in this state, bacteria are more resistant to sanitization and may serve as a continuous contam...

  6. Salmonella enterica Strains with Reduced Susceptibility to Quarternary Ammonium Compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Salmonella spp. are responsible for 76 million illnesses per year in the U.S. Quaternary ammonium compounds (QAC) are commonly used antimicrobial agents. Reduced susceptibility to these compounds by a broad spectrum of organisms is a concern. Methods: Salmonella enterica strains with r...

  7. Multilocus Sequence Typing as a Replacement for Serotyping in Salmonella enterica

    PubMed Central

    Zhou, Zhemin; Sangal, Vartul; Krauland, Mary G.; Hale, James L.; Harbottle, Heather; Uesbeck, Alexandra; Dougan, Gordon; Harrison, Lee H.; Brisse, Sylvain

    2012-01-01

    Salmonella enterica subspecies enterica is traditionally subdivided into serovars by serological and nutritional characteristics. We used Multilocus Sequence Typing (MLST) to assign 4,257 isolates from 554 serovars to 1092 sequence types (STs). The majority of the isolates and many STs were grouped into 138 genetically closely related clusters called eBurstGroups (eBGs). Many eBGs correspond to a serovar, for example most Typhimurium are in eBG1 and most Enteritidis are in eBG4, but many eBGs contained more than one serovar. Furthermore, most serovars were polyphyletic and are distributed across multiple unrelated eBGs. Thus, serovar designations confounded genetically unrelated isolates and failed to recognize natural evolutionary groupings. An inability of serotyping to correctly group isolates was most apparent for Paratyphi B and its variant Java. Most Paratyphi B were included within a sub-cluster of STs belonging to eBG5, which also encompasses a separate sub-cluster of Java STs. However, diphasic Java variants were also found in two other eBGs and monophasic Java variants were in four other eBGs or STs, one of which is in subspecies salamae and a second of which includes isolates assigned to Enteritidis, Dublin and monophasic Paratyphi B. Similarly, Choleraesuis was found in eBG6 and is closely related to Paratyphi C, which is in eBG20. However, Choleraesuis var. Decatur consists of isolates from seven other, unrelated eBGs or STs. The serological assignment of these Decatur isolates to Choleraesuis likely reflects lateral gene transfer of flagellar genes between unrelated bacteria plus purifying selection. By confounding multiple evolutionary groups, serotyping can be misleading about the disease potential of S. enterica. Unlike serotyping, MLST recognizes evolutionary groupings and we recommend that Salmonella classification by serotyping should be replaced by MLST or its equivalents. PMID:22737074

  8. Epidemiology of a Salmonella enterica subsp. enterica serovar Typhimurium strain associated with a songbird outbreak.

    PubMed

    Hernandez, Sonia M; Keel, Kevin; Sanchez, Susan; Trees, Eija; Gerner-Smidt, Peter; Adams, Jennifer K; Cheng, Ying; Ray, Al; Martin, Gordon; Presotto, Andrea; Ruder, Mark G; Brown, Justin; Blehert, David S; Cottrell, Walter; Maurer, John J

    2012-10-01

    Salmonella enterica subsp. enterica serovar Typhimurium is responsible for the majority of salmonellosis cases worldwide. This Salmonella serovar is also responsible for die-offs in songbird populations. In 2009, there was an S. Typhimurium epizootic reported in pine siskins in the eastern United States. At the time, there was also a human outbreak with this serovar that was associated with contaminated peanuts. As peanuts are also used in wild-bird food, it was hypothesized that the pine siskin epizootic was related to this human outbreak. A comparison of songbird and human S. Typhimurium pulsed-field gel electrophoresis (PFGE) patterns revealed that the epizootic was attributed not to the peanut-associated strain but, rather, to a songbird strain first characterized from an American goldfinch in 1998. This same S. Typhimurium strain (PFGE type A3) was also identified in the PulseNet USA database, accounting for 137 of 77,941 total S. Typhimurium PFGE entries. A second molecular typing method, multiple-locus variable-number tandem-repeat analysis (MLVA), confirmed that the same strain was responsible for the pine siskin epizootic in the eastern United States but was distinct from a genetically related strain isolated from pine siskins in Minnesota. The pine siskin A3 strain was first encountered in May 2008 in an American goldfinch and later in a northern cardinal at the start of the pine siskin epizootic. MLVA also confirmed the clonal nature of S. Typhimurium in songbirds and established that the pine siskin epizootic strain was unique to the finch family. For 2009, the distribution of PFGE type A3 in passerines and humans mirrored the highest population density of pine siskins for the East Coast. PMID:22885752

  9. Epidemiology of a Salmonella enterica subsp. Enterica serovar Typhimurium strain associated with a songbird outbreak.

    USGS Publications Warehouse

    Blehert, David S.; Hernandez, Sonia M.; Keel, Kevin; Sanchez, Susan; Trees, Eija; Peter Gerner-Smidt

    2012-01-01

    Salmonella enterica subsp. enterica serovar Typhimurium is responsible for the majority of salmonellosis cases worldwide. This Salmonella serovar is also responsible for die-offs in songbird populations. In 2009, there was an S. Typhimurium epizootic reported in pine siskins in the eastern United States. At the time, there was also a human outbreak with this serovar that was associated with contaminated peanuts. As peanuts are also used in wild-bird food, it was hypothesized that the pine siskin epizootic was related to this human outbreak. A comparison of songbird and human S. Typhimurium pulsed-field gel electrophoresis (PFGE) patterns revealed that the epizootic was attributed not to the peanut-associated strain but, rather, to a songbird strain first characterized from an American goldfinch in 1998. This same S. Typhimurium strain (PFGE type A3) was also identified in the PulseNet USA database, accounting for 137 of 77,941 total S. Typhimurium PFGE entries. A second molecular typing method, multiple-locus variable-number tandem-repeat analysis (MLVA), confirmed that the same strain was responsible for the pine siskin epizootic in the eastern United States but was distinct from a genetically related strain isolated from pine siskins in Minnesota. The pine siskin A3 strain was first encountered in May 2008 in an American goldfinch and later in a northern cardinal at the start of the pine siskin epizootic. MLVA also confirmed the clonal nature of S. Typhimurium in songbirds and established that the pine siskin epizootic strain was unique to the finch family. For 2009, the distribution of PFGE type A3 in passerines and humans mirrored the highest population density of pine siskins for the East Coast.

  10. Evaluation and comparison of molecular techniques for epidemiological typing of Salmonella enterica subsp. enterica serovar dublin.

    PubMed Central

    Liebisch, B; Schwarz, S

    1996-01-01

    A total of 28 unrelated isolates of the Salmonella enterica subsp. enterica serovar dublin (S. dublin) collected during a 6-year period, as well as four samples of the S. dublin live vaccine strain Bovisaloral and its prototype strain S. dublin 442/039, were investigated by different molecular typing methods for the following reasons: (i) to find the most discriminatory method for the epidemiological typing of isolates belonging to this Salmonella serovar and (ii) to evaluate these methods for their capacity to discriminate among the live vaccine strain Bovisaloral, its prototype strain S. dublin 442/039, and field isolates of the serovar dublin. Five different plasmid profiles were observed; a virulence plasmid of 76 kbp as identified by hybridization with an spvB-spvC gene probe was present in all isolates. The detection of 16S rRNA genes and that of IS200 elements proved to be unsuitable for the epidemiological typing of S. dublin; only one hybridization pattern could be observed with each of these methods. The results obtained from macrorestriction analysis strongly depended on the choice of restriction enzyme. While the enzyme NotI yielded the lowest discriminatory index among all enzymes tested, it was the only enzyme that allowed discrimination between the Bovisaloral vaccine strain and its prototype strain. In contrast to the enzymes XbaI and SpeI, which only differentiated among the S. dublin field isolates, XhoI as well as AvrII also produced restriction fragment patterns of the Bovisaloral strain and of its prototype strain that were not shared by any of the S. dublin field isolates. Macrorestriction analysis proved to be the most discriminatory method not only for the epidemiological typing of S. dublin field isolates but also for the identification of the S. dublin live vaccine strain Bovisaloral. PMID:8904430

  11. Virulence of Broad- and Narrow-Host-Range Salmonella enterica Serovars in the Streptomycin-Pretreated Mouse Model

    PubMed Central

    Suar, Mrutyunjay; Jantsch, Jonathan; Hapfelmeier, Siegfried; Kremer, Marcus; Stallmach, Thomas; Barrow, Paul A.; Hardt, Wolf-Dietrich

    2006-01-01

    Salmonella enterica subspecies I serovars are common bacterial pathogens causing diseases ranging from enterocolitis to systemic infections. Some serovars are adapted to specific hosts, whereas others have a broad host range. The molecular mechanisms defining the virulence characteristics and the host range of a given S. enterica serovar are unknown. Streptomycin pretreated mice provide a surrogate host model for studying molecular aspects of the intestinal inflammation (colitis) caused by serovar Typhimurium (S. Hapfelmeier and W. D. Hardt, Trends Microbiol. 13:497-503, 2005). Here, we studied whether this animal model is also useful for studying other S. enterica subspecies I serovars. All three tested strains of the broad-host-range serovar Enteritidis (125109, 5496/98, and 832/99) caused pronounced colitis and systemic infection in streptomycin pretreated mice. Different levels of virulence were observed among three tested strains of the host-adapted serovar Dublin (SARB13, SD2229, and SD3246). Several strains of host restricted serovars were also studied. Two serovar Pullorum strains (X3543 and 449/87) caused intermediate levels of colitis. No intestinal inflammation was observed upon infection with three different serovar Paratyphi A strains (SARB42, 2804/96, and 5314/98) and one serovar Gallinarum strain (X3796). A second serovar Gallinarum strain (287/91) was highly virulent and caused severe colitis. This strain awaits future analysis. In conclusion, the streptomycin pretreated mouse model can provide an additional tool to study virulence factors (i.e., those involved in enteropathogenesis) of various S. enterica subspecies I serovars. Five of these strains (125109, 2229, 287/91, 449/87, and SARB42) are subject of Salmonella genome sequencing projects. The streptomycin pretreated mouse model may be useful for testing hypotheses derived from this genomic data. PMID:16369020

  12. Draft Genome Sequence of a Salmonella enterica subsp. enterica Serovar Gallinarum bv. Gallinarum Isolate Associated with Fowl Typhoid Outbreaks in Brazil

    PubMed Central

    De Carli, Silvia; Gräf, Tiago; Mayer, Fabiana Q.; Cibulski, Samuel; Lehmann, Fernanda K. M.; Fonseca, André S. K.; Ikuta, Nilo

    2016-01-01

    Salmonella enterica subsp. enterica serovar Gallinarum bv. Gallinarum strains are bird pathogens causing fowl typhoid (FT). Isolate BR_RS12 was obtained from a poultry flock with FT in 2014. The sequencing of this genome will enable to track the origin of the recent outbreaks in Brazil. PMID:26950322

  13. Complete Closed Genome Sequences of Salmonella enterica subsp. enterica Serotypes Anatum, Montevideo, Typhimurium, and Newport, Isolated from Beef, Cattle, and Humans.

    PubMed

    Harhay, Dayna M; Bono, James L; Smith, Timothy P L; Fields, Patricia I; Dinsmore, Blake A; Santovenia, Monica; Kelley, Christy M; Wang, Rong; Harhay, Gregory P

    2016-01-01

    Salmonella enterica spp. are a diverse group of bacteria with a wide range of virulence potential. To facilitate genome comparisons across this virulence spectrum, we present eight complete closed genome sequences of four S. enterica serotypes (Anatum, Montevideo, Typhimurium, and Newport), isolated from various cattle samples and from humans. PMID:26847891

  14. Draft Genome Sequence and Annotation of Phyllosphere-Persisting Salmonella enterica subsp. enterica Serovar Livingstone Strain CKY-S4, Isolated from an Urban Lake in Regina, Canada.

    PubMed

    Tambalo, Dinah D; Perry, Benjamin J; Fitzgerald, Stephen F; Cameron, Andrew D S; Yost, Christopher K

    2015-01-01

    Here, we report the first draft genome sequence of Salmonella enterica subsp. enterica serovar Livingstone. This S. Livingstone strain CKY-S4 displayed biofilm formation and cellulose production and could persist on lettuce. This genome may help the study of mechanisms by which enteric pathogens colonize food crops. PMID:26272568

  15. Draft Genome Sequence and Annotation of Phyllosphere-Persisting Salmonella enterica subsp. enterica Serovar Livingstone Strain CKY-S4, Isolated from an Urban Lake in Regina, Canada

    PubMed Central

    Tambalo, Dinah D.; Perry, Benjamin J.; Fitzgerald, Stephen F.; Cameron, Andrew D. S.

    2015-01-01

    Here, we report the first draft genome sequence of Salmonella enterica subsp. enterica serovar Livingstone. This S. Livingstone strain CKY-S4 displayed biofilm formation and cellulose production and could persist on lettuce. This genome may help the study of mechanisms by which enteric pathogens colonize food crops. PMID:26272568

  16. Draft Genome Sequence of Salmonella enterica subsp. enterica Serovar Napoli Strain SN310, Cause of a Multischool Outbreak in Milan, Italy, in 2014.

    PubMed

    Huedo, Pol; Gori, Maria; Scaltriti, Erika; Morganti, Marina; Casadei, Gabriele; Amato, Ettore; Pontello, Mirella

    2015-01-01

    We report the draft genome sequence of Salmonella enterica subsp. enterica serovar Napoli strain SN310, isolated from a stool sample of an affected pupil during a multischool outbreak in 2014 in Milan, Italy. This represents the first reported draft genome sequence of the emerging serovar Napoli. PMID:26358605

  17. Complete closed genome sequences of Salmonella enterica subsp. enterica serotypes Anatum, Montevideo, Typhimurium and Newport, isolated from beef, cattle, and humans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica are a versatile group of bacteria with a wide range in virulence potential. To facilitate genome comparisons across this virulence spectrum, we present eight complete closed genome sequences of four S. enterica serotypes (Anatum, Montevideo, Typhimurium, and Newport) isolated fro...

  18. Complete and closed genome sequences of 10 Salmonella enterica subsp. enterica serovar Anatum isolated from human and bovine sources

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is an important pathogen transmitted by numerous vectors. Genomic comparisons of Salmonella from disparate hosts have the potential to further our understanding of mechanisms underlying host specificities and virulence. Here, we present closed genome and plasmid sequences of 10...

  19. Quantification of the Sensitivity of Mycobacterium avium subsp paratuberculosis and Salmonella enterica subsp enterica to Low pH and High Organic Acids using Propidium Monoazide and Quantitative PCR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mycobacterium avium subsp paratuberculosis (Map) and Salmonella enterica subsp enterica (S. enterica) are two pathogens that are a concern to food and animal safety due to their ability to withstand harsh conditions encountered in the natural environment and within the host during pathogenesis. Acid...

  20. E-nose identification of Salmonella enterica in poultry manure.

    PubMed

    Kizil, Ü; Genç, L; Genç, T T; Rahman, S; Khaitsa, M L

    2015-04-01

    A DiagNose II electronic nose (e-nose) system was tested to evaluate the performance of such systems in the detection of the Salmonella enterica pathogen in poultry manure. To build a database, poultry manure samples were collected from 7 broiler houses, samples were homogenised, and subdivided into 4 portions. One portion was left as is; the other three portions were artificially infected with S. enterica. An artificial neural network (ANN) model was developed and validated using the developed database. In order to test the performance of DiagNose II and the ANN model, 16 manure samples were collected from 6 different broiler houses and tested using these two systems. The results showed that DiagNose II was able to classify manure samples correctly as infected or non-infected based on the ANN model developed with a 94% level of accuracy. PMID:25650129

  1. Quantitative Oligonucleotide Microarray Fingerprinting of Salmonella enterica isolates

    SciTech Connect

    Willse, Alan R.; Straub, Tim M.; Wunschel, Sharon C.; Small, Jack A.; Call, Douglas R.; Daly, Don S.; Chandler, Darrell P.

    2004-03-22

    We report on a genome-independent microbial fingerprinting method using nucleic acid microarrays for microbial forensics and epidemiology applications. We demonstrate that the microarray method provides high-resolution differentiation between closely related microorganisms using Salmonella enterica strains. In replicate trials we used a simple 192-probe nonamer array to construct a fingerprint library of 25 closely related Salmonella isolates. Controlling false discovery rate for multiple testing at alpha =.05, at least 295 of 300 pairs of S. enterica isolate fingerprints were found to be statistically distinct using a modified Hotelling Tsquared test. Although we find most pairs of Salmonella fingerprints to be distinct, forensic applications will also require a protocol for library construction and reliable microbial classification against a fingerprint library. We outline additional steps required to produce a protocol for library construction and reliable classification of unknown organisms.

  2. Transcriptional profile of Salmonella enterica subsp. enterica serovar Weltevreden during alfalfa sprout colonization

    PubMed Central

    Brankatschk, Kerstin; Kamber, Tim; Pothier, Joël F; Duffy, Brion; Smits, Theo H M

    2014-01-01

    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 transcribed at higher levels with sprouts and in minimal medium respectively. Genes that were higher transcribed with sprouts are coding for proteins involved in mechanisms known to be important for attachment, motility and biofilm formation. Besides gene expression required for phenotypic adaption, genes involved in sulphate acquisition were higher transcribed, suggesting that the surface on alfalfa sprouts may be poor in sulphate. Genes encoding structural and effector proteins of Salmonella pathogenicity island 2, involved in survival within macrophages during infection of animal tissue, were higher transcribed with sprouts possibly as a response to environmental conditions. This study provides insight on additional mechanisms that may be important for pathogen interactions with sprouts. PMID:24308841

  3. Chromosome-Mediated Multidrug Resistance in Salmonella enterica Serovar Typhi

    PubMed Central

    Alam, Munirul; Kuo, Jung-Che; Liu, Yen-Yi; Wang, Pei-Jen

    2014-01-01

    A salmonella genomic island, designated SGI11, was found in 18 of 26 multidrug-resistant Salmonella enterica serovar Typhi isolates from Bangladesh. SGI11 was an IS1 composite transposon and carried 7 resistance genes that conferred resistance to 5 first-line antimicrobials. Eleven of the 18 SGI11-carrying S. Typhi isolates had developed resistance to high levels of ciprofloxacin. PMID:25367917

  4. Regulation of the ansB gene of Salmonella enterica.

    PubMed

    Jennings, M P; Scott, S P; Beacham, I R

    1993-07-01

    The expression of L-asparaginase II (encoded by ansB) in Salmonella enterica was found to be positively regulated by the cAMP receptor protein (CRP) and anaerobiosis. The anaerobic regulation of the S. enterica ansB gene is not mediated by the anaerobic transcriptional activator FNR. This is unlike the situation of the ansB gene of Escherichia coli, which is dependent on both CRP and FNR. To investigate this fundamental difference in the regulation of L-asparaginase II expression in S. enterica, the ansB gene was cloned and the nucleotide sequence of the promoter region determined. Sequence analysis and transcript mapping of the 5' promoter region revealed a single transcriptional start point (tsp) and two regulatory sites with substantial homology with those found in E. coli. One site, centred -90.5 bp from the tsp, is homologous to a hybrid CRP/FNR ('CF') site which is the site of CRP regulation in the E. coli promoter. The other site, centred 40.5 bp upstream of the tsp, is homologous to the FNR binding site of the E. coli promoter. Significantly, however, a single base-pair difference exists in this site, at a position of the related CRP and FNR DNA-binding site consensus sequences known to be involved in CRP versus FNR specificity. Site-directed mutagenesis indicates that this single difference, relative to the homologous E. coli site, results in a CRP binding site and the observed FNR-independent ansB expression in S. enterica.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8412661

  5. Mobilome differences between Salmonella enterica serovars Anatum and Typhimurium isolated from cattle and humans and potential impact on virulence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica is an important group of pathogens capable of inhabiting a range of niches and hosts with varying degrees of impact, from commensal colonization to invasive infection. Recent outbreaks of multi-drug resistant S. enterica, attributed to consumption of contaminated ...

  6. Development of a rapid serotyping method for Salmonella enterica using serotype-specific single-nucleotide polymorphisms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica serotype Enteriditis (S. Enteriditis) is the leading cause of salmonellosis worldwide, including the USA. Many S. enterica serotypes known to cause foodborne disease are associated with broiler meat contamination. While some serotypes are specific to birds (S. e...

  7. A Highly Effective Component Vaccine against Nontyphoidal Salmonella enterica Infections

    PubMed Central

    Ferreira, Rosana B. R.; Valdez, Yanet; Coombes, Brian K.; Sad, Subash; Gouw, Joost W.; Brown, Eric M.; Li, Yuling; Grassl, Guntram A.; Antunes, L. Caetano M.; Gill, Navkiran; Truong, Mimi; Scholz, Roland; Reynolds, Lisa A.; Krishnan, Laskshmi; Zafer, Ahmed A.; Sal-Man, Neta; Lowden, Michael J.; Auweter, Sigrid D.; Foster, Leonard J.

    2015-01-01

    ABSTRACT Nontyphoidal Salmonella enterica (NTS) infections are a major burden to global public health, as they lead to diseases ranging from gastroenteritis to systemic infections and there is currently no vaccine available. Here, we describe a highly effective component vaccine against S. enterica serovar Typhimurium in both gastroenteritis and systemic murine infection models. We devised an approach to generate supernatants of S. enterica serovar Typhimurium, an organism that is highly abundant in virulence factors. Immunization of mice with this supernatant resulted in dramatic protection against a challenge with serovar Typhimurium, showing increased survival in the systemic model and decreased intestinal pathology in the gastrointestinal model. Protection correlated with specific IgA and IgG levels in the serum and specific secretory IgA levels in the feces of immunized mice. Initial characterization of the protective antigens in the bacterial culture supernatants revealed a subset of antigens that exhibited remarkable stability, a highly desirable characteristic of an effective vaccine to be used under suboptimal environmental conditions in developing countries. We were able to purify a subset of the peptides present in the supernatants and show their potential for immunization of mice against serovar Typhimurium resulting in a decreased level of colonization. This component vaccine shows promise with regard to protecting against NTS, and further work should significantly help to establish vaccines against these prevalent infections. PMID:26396246

  8. Structures of the SEp22 dodecamer, a Dps-like protein from Salmonella enterica subsp. enterica serovar Enteritidis

    PubMed Central

    Miyamoto, Takanori; Asahina, Yasuko; Miyazaki, Shohei; Shimizu, Hidetoshi; Ohto, Umeharu; Noguchi, Shuji; Satow, Yoshinori

    2011-01-01

    The crystal structure of SEp22, a DNA-binding protein from starved cells from Salmonella enterica subsp. enterica serovar Enteritidis, has been determined in two forms: the native state at 1.25 Å resolution and an iron-soaked form at 1.30 Å resolution. The SEp22 protomers form a dodecameric shell with 23 symmetry and a single iron ion per protomer was found at the ferroxidase centre in the iron-soaked form. Along the threefold axes of the 23 symmetry, hydrophilic Asp channels that consist of Asp146 were found. Iron ions may flow into the cavity of the dodecameric shell through the Asp channels. PMID:21206015

  9. Antibiotic resistant Escherichia coli and Salmonella enterica in the beef production and processing chain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Concerns have been raised that extended-spectrum cephalosporin-resistant Escherichia coli (CefR EC), trimethoprim-sulfamethoxazole-resistant E. coli (TxsR EC), extended-spectrum cephalosporin-resistant Salmonella enterica (CefR SE), and nalidixic acid-resistant S. enterica (NalR SE) in c...

  10. Genome-scale screening and validation of targets for identification of Salmonella enterica and serovar prediction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is the most common foodborne pathogen worldwide, with a great diversity of 2500 recognized serovars. Detection of S. enterica and its classification into serovars are essential for food safety surveillance and clinical diagnosis. Recently, the polymerase chain reaction (PCR) meth...

  11. Improvements to a PCR-based serogrouping scheme for Salmonella enterica from dairy farm samples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The PCR method described by Herrera-León, et al. (Research in Microbiology 158:122-127, 2007) has proved to be a simple and useful technique for characterizing isolates of Salmonella enterica enterica belonging to serogroups B, C1, C2, D1, and E1, groups which encompass a majority of the isolates fr...

  12. Role of Soil, Crop Debris, and a Plant Pathogen in Salmonella enterica Contamination of Tomato Plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: In the U.S., tomatoes have become the most implicated vehicle for produce-associated Salmonellosis with 12 outbreaks since 1998. Although unconfirmed, trace backs suggest pre-harvest contamination with Salmonella enterica. Routes of tomato crop contamination by S. enterica in the absence...

  13. [Fluorescent and Magnetic Relaxation Switch Immunosensor for the Detecting Foodborne Pathogen Salmonella enterica in Water Samples].

    PubMed

    Wang, Song-bai; Zhang, Yan; An, Wen-ting; Wei, Yan-li; Wang, Yu; Shuang, Shao-min

    2015-11-01

    Fluoroimmunoassay based on quantum dots (QDs) and magnetic relaxation switch (MRS) immunoassay based on superparamagnetic nanoparticles (SMN) were constructed to detect Salmonella enterica (S. enterica) in water samples. In fluoroimmunoassay, magnetic beads was conjugated with S. enterica capture antibody (MB-Ab2) to enrich S. enterica from sample solution, then the QDs was conjugated with the S. enterica detection antibody (QDs-Ab1) to detect S. enterica based on sandwich immunoassay format. And the fluorescence intensity is positive related to the bacteria concentration of the sample. Results showed that the limit of detection (LOD) of this method was 102 cfu · mL⁻¹ and analysis time was 2 h. In MRS assay, magnetic nanoparticle-antibody conjugate (MN-Ab1) can switch their dispersed and aggregated state in the presence of the target. This state of change can modulate the spin-spin relaxation time (T₂) of the neighboring water molecule. The change in T₂(ΔT₂) positively correlates with the amount of the target in the sample. Thus, AT can be used as a detection signal in MRS immunosensors. Results showed that LOD of MRS sensor for S. enterica was 10³ cfu · mL⁻¹ and analysis time was 0.5 h. Two methods were compared in terms of advantages and disadvantages in detecting S. enterica. PMID:26978918

  14. Genome-Scale Screening and Validation of Targets for Identification of Salmonella enterica and Serovar Prediction.

    PubMed

    Zhou, Xiujuan; Zhang, Lida; Shi, Chunlei; Fratamico, Pina M; Liu, Bin; Paoli, George C; Dan, Xianlong; Zhuang, Xiaofei; Cui, Yan; Wang, Dapeng; Shi, Xianming

    2016-03-01

    Salmonella enterica is the most common foodborne pathogen worldwide, with 2,500 recognized serovars. Detection of S. enterica and its classification into serovars are essential for food safety surveillance and clinical diagnosis. The PCR method is useful for these applications because of its rapidity and high accuracy. We obtained 412 candidate detection targets for S. enterica using a comparative genomics mining approach. Gene ontology (GO) functional enrichment analysis of these candidate targets revealed that the GO term with the largest number of unigenes with known function (38 of 177, 21.5%) was significantly involved in pathogenesis (P < 10(-24)). All the candidate targets were then evaluated by PCR assays. Fifteen targets showed high specificity for the detection of S. enterica by verification with 151 S. enterica strains and 34 non-Salmonella strains. The phylogenetic trees of verified targets were highly comparable with those of housekeeping genes, especially for differentiating S. enterica strains into serovars. The serovar prediction ability was validated by sequencing one target (S9) for 39 S. enterica strains belonging to six serovars. Identical mutation sites existed in the same serovar, and different mutation sites were found in diverse serovars. Our findings revealed that 15 verified targets can be potentially used for molecular detection, and some of them can be used for serotyping of S. enterica strains. PMID:26939647

  15. Studies on Biofilm Formation and Interactions of Salmonella enterica with Romaine-Lettuce Leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The association between biofilm formation and the interactions of Salmonella enterica serovars with cut-Romaine-lettuce leaves was investigated. Biofilm formation by 8 S. enterica serovars was tested on polystyrene microtiter plates in the presence of different growth media. Maximal biofilm mass was...

  16. Genome sequences of ten Salmonella enterica serovars isolated from a single dairy farm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Here we report draft genomes of twenty-seven isolates of Salmonella enterica subsp. enterica representing the seven serotypes isolated from cows in a Pennsylvania dairy herd, the farm on which they were reared, and the associated off-site heifer-raising facility over an eight year sampling period. ...

  17. Previously uncharacterized Salmonella enterica genes required for swarming play a role in seedling colonization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Incidences of bacterial foodborne illness caused by ingestion of fresh produce are rising. Instead of being a case of incidental contamination, the animal pathogen Salmonella enterica utilizes specific molecular mechanisms to attach to and colonize plants. This work characterizes two S. enterica gen...

  18. Complete Genome Sequence of Salmonella enterica subsp. enterica Serovar Indiana C629, a Carbapenem-Resistant Bacterium Isolated from Chicken Carcass in China

    PubMed Central

    Liu, Feng; Peng, Zixin; Li, Fengqin

    2016-01-01

    The carbapenem-resistant Salmonella enterica subsp. enterica serovar Indiana strain C629 was isolated from a chicken carcass collected from a slaughterhouse in Qingdao, China. The complete genome sequence of C629 contains a circular 4,791,723-bp chromosome and a circular 210,106-bp plasmid. Genes involved in carbapenem resistance of this bacterium were identified by whole-genome analysis. PMID:27417837

  19. Population structures in the SARA and SARB reference collections of Salmonella enterica according to MLST, MLEE and microarray hybridization.

    PubMed

    Achtman, Mark; Hale, James; Murphy, Ronan A; Boyd, E Fidelma; Porwollik, Steffen

    2013-06-01

    In the 1980's and 1990's, population genetic analyses based on Multilocus Enzyme Electrophoresis (MLEE) provided an initial overview of the genetic diversity of multiple bacterial species, including Salmonella enterica. The genetic diversity within S. enterica subspecies enterica according to MLEE is represented by the SARA and SARB reference collections, each consisting of 72 isolates, which have been extensively used for comparative analyses. MLEE has subsequently been replaced by Multilocus Sequence Typing (MLST). Our initial MLST results indicated that some strains within the SARB collection differed from their published descriptions. We therefore performed MLST on four versions of the SARB collection from different sources and one collection of SARA, and found that multiple isolates in SARB and SARA differ in serovar from their original description, and other SARB isolates differed between different sources. Comparisons with a global MLST database allowed a plausible reconstruction of the serovars of the original collection. MLEE, MLST and microarrays were largely concordant at recognizing closely related strains. MLST was particularly effective at recognizing discrete population genetic groupings while the two other methods provided hints of higher order relationships. However, quantitative pair-wise phylogenetic distances differed considerably between all three methods. Our results provide a translation dictionary from MLEE to MLST for the extant SARA and SARB collections which can facilitate genomic comparisons based on archival insights from MLEE. PMID:23507027

  20. Novel small RNA (sRNA) landscape of the starvation-stress response transcriptome of Salmonella enterica serovar typhimurium.

    PubMed

    Amin, Shivam V; Roberts, Justin T; Patterson, Dillon G; Coley, Alexander B; Allred, Jonathan A; Denner, Jason M; Johnson, Justin P; Mullen, Genevieve E; O'Neal, Trenton K; Smith, Jason T; Cardin, Sara E; Carr, Hank T; Carr, Stacie L; Cowart, Holly E; DaCosta, David H; Herring, Brendon R; King, Valeria M; Polska, Caroline J; Ward, Erin E; Wise, Alice A; McAllister, Kathleen N; Chevalier, David; Spector, Michael P; Borchert, Glen M

    2016-03-01

    Small RNAs (sRNAs) are short (∼50-200 nucleotides) noncoding RNAs that regulate cellular activities across bacteria. Salmonella enterica starved of a carbon-energy (C) source experience a host of genetic and physiological changes broadly referred to as the starvation-stress response (SSR). In an attempt to identify novel sRNAs contributing to SSR control, we grew log-phase, 5-h C-starved and 24-h C-starved cultures of the virulent Salmonella enterica subspecies enterica serovar Typhimurium strain SL1344 and comprehensively sequenced their small RNA transcriptomes. Strikingly, after employing a novel strategy for sRNA discovery based on identifying dynamic transcripts arising from "gene-empty" regions, we identify 58 wholly undescribed Salmonella sRNA genes potentially regulating SSR averaging an ∼1,000-fold change in expression between log-phase and C-starved cells. Importantly, the expressions of individual sRNA loci were confirmed by both comprehensive transcriptome analyses and northern blotting of select candidates. Of note, we find 43 candidate sRNAs share significant sequence identity to characterized sRNAs in other bacteria, and ∼70% of our sRNAs likely assume characteristic sRNA structural conformations. In addition, we find 53 of our 58 candidate sRNAs either overlap neighboring mRNA loci or share significant sequence complementarity to mRNAs transcribed elsewhere in the SL1344 genome strongly suggesting they regulate the expression of transcripts via antisense base-pairing. Finally, in addition to this work resulting in the identification of 58 entirely novel Salmonella enterica genes likely participating in the SSR, we also find evidence suggesting that sRNAs are significantly more prevalent than currently appreciated and that Salmonella sRNAs may actually number in the thousands. PMID:26853797

  1. Mechanisms of antimicrobial resistant Salmonella enterica transmission associated with starling-livestock interactions.

    PubMed

    Carlson, James C; Hyatt, Doreene R; Ellis, Jeremy W; Pipkin, David R; Mangan, Anna M; Russell, Michael; Bolte, Denise S; Engeman, Richard M; DeLiberto, Thomas J; Linz, George M

    2015-08-31

    Bird-livestock interactions have been implicated as potential sources for bacteria within concentrated animal feeding operations (CAFO). European starlings (Sturnus vulgaris) in particular are known to contaminate cattle feed and water with Salmonella enterica through their fecal waste. We propose that fecal waste is not the only mechanisms through which starlings introduce S. enterica to CAFO. The goal of this study was to assess if starlings can mechanically move S. enterica. We define mechanical movement as the transportation of media containing S. enterica, on the exterior of starlings within CAFO. We collected 100 starlings and obtained external wash and gastrointestinal tract (GI) samples. We also collected 100 samples from animal pens. Within each pen we collected one cattle fecal, feed, and water trough sample. Isolates from all S. enterica positive samples were subjected to antimicrobial susceptibility testing. All sample types, including 17% of external starling wash samples, contained S. enterica. All sample types had at least one antimicrobial resistant (AMR) isolate and starling GI samples harbored multidrug resistant S. enterica. The serotypes isolated from the starling external wash samples were all found in the farm environment and 11.8% (2/17) of isolates from positive starling external wash samples were resistant to at least one class of antibiotics. This study provides evidence of a potential mechanism of wildlife introduced microbial contamination in CAFO. Mechanical movement of microbiological hazards, by starlings, should be considered a potential source of bacteria that is of concern to veterinary, environmental and public health. PMID:25960334

  2. Changes in the Porcine Intestinal Microbiome in Response to Infection with Salmonella enterica and Lawsonia intracellularis

    PubMed Central

    Singer, Randall S.; Gebhart, Connie J.; Sreevatsan, Srinand; Johnson, Timothy; Isaacson, Richard E.

    2015-01-01

    Salmonella enterica is a leading cause of food borne illness. Recent studies have shown that S. enterica is a pathogen capable of causing alterations to the composition of the intestinal microbiome. A recent prospective study of French pork production farms found a statistically significant association between Lawsonia intracellularis and carriage of S. enterica. In the current study the composition of the gut microbiome was determined in pigs challenged with S. enterica serovar Typhimurium and or L. intracellularis and compared to non-challenged control pigs. Principal coordinate analysis demonstrated that there was a disruption in the composition of the gut microbiome in the colon and cecum of pigs challenged with either pathogen. The compositions of the microbiomes of challenged pigs were similar to each other but differed from the non-challenged controls. There also were statistically significant increases in Anaerobacter, Barnesiella, Pediococcus, Sporacetigenium, Turicibacter, Catenibacterium, Prevotella, Pseudobutyrivibrio, and Xylanibacter in the challenged pigs. To determine if these changes were specific to experimentally challenged pigs, we determined the compositions of the fecal microbiomes of naturally infected pigs that were carriers of S. enterica. Pigs that were frequent shedders of S. enterica were shown to have similar fecal microbiomes compared to non-shedders or pigs that shed S. enterica infrequently. In a comparison of the differentially abundant bacteria in the naturally infected pigs compared to experimentally challenged pigs, 9 genera were differentially abundant and each exhibited the same increase or decrease in abundance between the two groups. Thus, there were similar changes in the GI microbiome associated with carriage of S. enterica regardless of whether the pigs were experimentally challenged with S. enterica or acquired it naturally. PMID:26461107

  3. Changes in the Porcine Intestinal Microbiome in Response to Infection with Salmonella enterica and Lawsonia intracellularis.

    PubMed

    Borewicz, Klaudyna A; Kim, Hyeun Bum; Singer, Randall S; Gebhart, Connie J; Sreevatsan, Srinand; Johnson, Timothy; Isaacson, Richard E

    2015-01-01

    Salmonella enterica is a leading cause of food borne illness. Recent studies have shown that S. enterica is a pathogen capable of causing alterations to the composition of the intestinal microbiome. A recent prospective study of French pork production farms found a statistically significant association between Lawsonia intracellularis and carriage of S. enterica. In the current study the composition of the gut microbiome was determined in pigs challenged with S. enterica serovar Typhimurium and or L. intracellularis and compared to non-challenged control pigs. Principal coordinate analysis demonstrated that there was a disruption in the composition of the gut microbiome in the colon and cecum of pigs challenged with either pathogen. The compositions of the microbiomes of challenged pigs were similar to each other but differed from the non-challenged controls. There also were statistically significant increases in Anaerobacter, Barnesiella, Pediococcus, Sporacetigenium, Turicibacter, Catenibacterium, Prevotella, Pseudobutyrivibrio, and Xylanibacter in the challenged pigs. To determine if these changes were specific to experimentally challenged pigs, we determined the compositions of the fecal microbiomes of naturally infected pigs that were carriers of S. enterica. Pigs that were frequent shedders of S. enterica were shown to have similar fecal microbiomes compared to non-shedders or pigs that shed S. enterica infrequently. In a comparison of the differentially abundant bacteria in the naturally infected pigs compared to experimentally challenged pigs, 9 genera were differentially abundant and each exhibited the same increase or decrease in abundance between the two groups. Thus, there were similar changes in the GI microbiome associated with carriage of S. enterica regardless of whether the pigs were experimentally challenged with S. enterica or acquired it naturally. PMID:26461107

  4. Mannanoligosaccharide agglutination by Salmonella enterica strains isolated from carrier pigs

    PubMed Central

    Borowsky, Luciane; Corção, Gertrudes; Cardoso, Marisa

    2009-01-01

    Type-1 fimbriae are associated with most Salmonella enterica serovars and are an essential factor for host colonization. Mannanoligosaccharides (MOS), a prebiotic that is agglutinated by type-1 fimbriae, are proposed for the control of enterobacteria colonization and may be an alternative to Salmonella control in pigs. The aim of this study was to evaluate the capability of porcine Salmonella strains to adhere to MOS in vitro. A total of 108 strains of Salmonella sp. isolated from carrier pigs were evaluated for the amplification of fimA and fimH genes, agglutination of MOS and hemagglutination. In all tested strains, amplicons of expected size were detected for both fimA and fimH gene. In the hemagglutination assays, 31 (28.7%) strains presented mannose–sensitive agglutination of erythrocytes, indicating that the strains were expressing type-1 fimbriae. Considering only strains expressing the type-1 fimbriae, 23 (74.2%) presented a strong agglutination of MOS, 3 (9.6%) a weak reaction and 5 (16.2%) none. The results indicate that Salmonella enterica strains expressing type-1 fimbriae can agglutinate effectively in vitro to MOS. PMID:24031388

  5. Molecular identification of Salmonella enterica subsp. enterica serovar Gallinarum biovars Gallinarum and Pullorum by a duplex PCR assay.

    PubMed

    Batista, Diego Felipe Alves; de Freitas Neto, Oliveiro Caetano; de Almeida, Adriana Maria; Barrow, Paul Andrew; de Oliveira Barbosa, Fernanda; Berchieri Junior, Angelo

    2016-07-01

    Salmonella enterica subsp. enterica serovar Gallinarum biovar Gallinarum (S Gallinarum) and biovar Pullorum (S Pullorum) are 2 poultry pathogens that cause major economic losses to the poultry industry worldwide. Control of both diseases mainly relies on the adoption of biosecurity programs, and success is dependent on accurate and fast detection. Based on this concept, we developed a duplex PCR assay, targeting 2 chromosomal sequences, which allowed us to precisely identify and differentiate S Gallinarum and S Pullorum field strains. This assay was validated by testing genomic DNA from 40 S Gallinarum and 29 S Pullorum field strains, 87 other Salmonella serovars, and 7 non-Salmonella strains. The serovar identifier region (SIR) primers produced a fragment only in S Gallinarum and S Pullorum strains, whereas the fragment from the ratA coding sequence, which was previously demonstrated to differentiate the 2 biovars, was also amplified from other Salmonella serovars. Our results showed that the combination of both SIR and ratA amplifications could be used to identify as well as to differentiate colonies of S Gallinarum and S Pullorum reliably. Thus, we believe this methodology can be a useful ancillary tool for routine veterinary diagnostic laboratories by providing rapid, accurate results. PMID:27216724

  6. Genomic Epidemiology of Salmonella enterica Serotype Enteritidis based on Population Structure of Prevalent Lineages

    PubMed Central

    Desai, Prerak T.; den Bakker, Henk C.; Mikoleit, Matthew; Tolar, Beth; Trees, Eija; Hendriksen, Rene S.; Frye, Jonathan G.; Porwollik, Steffen; Weimer, Bart C.; Wiedmann, Martin; Weinstock, George M.; Fields, Patricia I.; McClelland, Michael

    2014-01-01

    Salmonella enterica serotype Enteritidis is one of the most commonly reported causes of human salmonellosis. Its low genetic diversity, measured by fingerprinting methods, has made subtyping a challenge. We used whole-genome sequencing to characterize 125 S. enterica Enteritidis and 3 S. enterica serotype Nitra strains. Single-nucleotide polymorphisms were filtered to identify 4,887 reliable loci that distinguished all isolates from each other. Our whole-genome single-nucleotide polymorphism typing approach was robust for S. enterica Enteritidis subtyping with combined data for different strains from 2 different sequencing platforms. Five major genetic lineages were recognized, which revealed possible patterns of geographic and epidemiologic distribution. Analyses on the population dynamics and evolutionary history estimated that major lineages emerged during the 17th–18th centuries and diversified during the 1920s and 1950s. PMID:25147968

  7. Intestinal Cytokine Responses to Salmonella enterica Serovar Typhimurium Infection in Young Chicks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar typhimurium is one of the most frequently isolated strains in human salmonellosis worldwide, and is commonly found in broilers. Successful prevention and control of Salmonella colonization in poultry require better understanding of intestinal mucosal immune response to ...

  8. Antimicrobial susceptibility and plasmid replicon typing of Salmonella enterica serovar Kentucky isolates recovered from broilers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the United States, Salmonella enterica serotype Kentucky has become the predominate serotype recovered from broiler slaughter samples and the prevalence of resistance to streptomycin and tetracycline has increased dramatically in this serotype. To characterize the relationships between antimicro...

  9. Characterization of the novel T4-like Salmonella enterica bacteriophage STP4-a and its endolysin.

    PubMed

    Li, Meng; Li, Mengzhe; Lin, Hong; Wang, Jingxue; Jin, Yanqiu; Han, Feng

    2016-02-01

    While screening for new antimicrobial agents for multidrug-resistant Salmonella enterica, the novel lytic bacteriophage STP4-a was isolated and characterized. Phage morphology revealed that STP4-a belongs to the family Myoviridae. Bacterial challenge assays showed that different serovars of Salmonella enterica were susceptible to STP4-a infection. The genomic characteristics of STP4-a, containing 159,914 bp of dsDNA with an average GC content of 36.86 %, were determined. Furthermore, the endolysin of STP4-a was expressed and characterized. The novel endolysin, LysSTP4, has hydrolytic activity towards outer-membrane-permeabilized S. enterica and Escherichia coli. These results provide essential information for the development of novel phage-based biocontrol agents against S. enterica. PMID:26563319

  10. Identification and characterization of multidrug-resistant Salmonella enterica serotype Albert isolates in the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is one of the most common causes of bacterial foodborne illness in the United States. Although most Salmonella infections are self-limiting, antimicrobial treatment is critical for invasive salmonellosis. Primary antimicrobial treatment options include fluoroquinolones or extende...

  11. Differential Responses of Macrophages to Salmonella enterica Serovars Enteritidis and Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Macrophages are major effectors against Salmonella infection, and also transport bacteria between host tissues and provide a protected site for intracellular bacterial replication. We hypothesized that differences in chicken macrophage responses to Salmonella enterica serovar Enteritidis (SE) and s...

  12. Analysis of Plasmid and Chromosomal DNA of Multidrug-Resistant Salmonella enterica Serovar Typhi from Asia

    PubMed Central

    Mirza, S.; Kariuki, S.; Mamun, K. Z.; Beeching, N. J.; Hart, C. A.

    2000-01-01

    Molecular analysis of chromosomal DNA from 193 multidrug-resistant (MDR) Salmonella enterica serovar Typhi isolates from 1990 to 1995 from Pakistan, Kuwait, Malaysia, Bangladesh, and India produced a total of five major different pulsed-field gel electrophoresis (PFGE) patterns. Even within a particular country MDR S. enterica serovar Typhi DNA was found to be in different PFGE groups. Similar self-transferable 98-MDa plasmids belonging to either incompatibility group incHI1 or incHI1/FIIA were implicated in the MDR phenotype in S. enterica serovar Typhi isolates from all the locations except Quetta, Pakistan, where the majority were of incFIA. A total of five different PFGE genotypes with six different plasmids, based on incompatibility and restriction endonuclease analysis groups, were found among these MDR S. enterica serovar Typhi isolates. PMID:10747124

  13. Increased water activity reduces the thermal resistance of Salmonella enterica in peanut butter.

    PubMed

    He, Yingshu; Li, Ye; Salazar, Joelle K; Yang, Jingyun; Tortorello, Mary Lou; Zhang, Wei

    2013-08-01

    Increased water activity in peanut butter significantly (P < 0.05) reduced the heat resistance of desiccation-stressed Salmonella enterica serotypes treated at 90 °C. The difference in thermal resistance was less notable when strains were treated at 126 °C. Using scanning electron microscopy, we observed minor morphological changes of S. enterica cells resulting from desiccation and rehydration processes in peanut oil. PMID:23728806

  14. Draft Genome Sequences of 33 Salmonella enterica Clinical and Wildlife Isolates from Chile

    PubMed Central

    Toro, Magaly; Allard, Marc; Brown, Eric W.; Evans, Peter

    2015-01-01

    Salmonella enterica causes health problem worldwide. The relationships among strains that are from the same serotype but different hosts, countries, and continents remain elusive. Few genome sequences are available from S. enterica isolates from South America. Therefore, we sequenced the genomes of 33 strains from diverse sources isolated in Chile and determined that they were of different serotypes. These genomes will improve phylogenetic analysis of Salmonella strains from Chile and the rest of South America. PMID:25792040

  15. Pork Meat as a Potential Source of Salmonella enterica subsp. arizonae Infection in Humans

    PubMed Central

    Kritas, Spyridon; Govaris, Alexander; Burriel, Angeliki R.

    2014-01-01

    Salmonella enterica subsp. arizonae was isolated from 13 of 123 slaughtered pigs in central Greece. The samples cultured were feces, ileum tissue, mesenteric lymph nodes, and gallbladder swabs. A total of 74 isolates from 492 samples were identified as Salmonella spp. by use of standard laboratory culture media and two commercial micromethods and by use of a polyvalent slide agglutination test for the detection of O and H antigens. Among them were 19 (25.68%) suspected to be S. enterica subsp. arizonae according to analysis with standard laboratory culture media. Of those, 14 were identified as S. enterica subsp. arizonae by the API 20E (bioMérieux, France) and the Microgen GnA+B-ID (Microgen Bioproducts, Ltd., United Kingdom) identification systems. All the isolates were tested for resistance to 23 antimicrobials. Strains identified as S. enterica subsp. arizonae were resistant to 17 (70.8%) antibiotics. The highest proportions of resistance were observed for sulfamethoxazole-trimethoprim (71.4%), tetracycline (71.4%), ampicillin (64.3%), and amoxicillin (57.1%). Two isolates were resistant to aztreonam (7.1%) and tigecycline (7.1%), used only for the treatment of humans. Thus, pork meat may play a role in the transmission of antibiotic-resistant S. enterica subsp. arizonae to human consumers. This is the first report of S. enterica subsp. arizonae isolation from pigs. PMID:24335956

  16. Molecular characterization of Salmonella enterica isolates associated with starling-livestock interactions.

    PubMed

    Carlson, James C; Hyatt, Doreene R; Bentler, Kevin; Mangan, Anna M; Russell, Michael; Piaggio, Antoinette J; Linz, George M

    2015-08-31

    Bird-livestock interactions have been implicated as potential sources for bacteria within concentrated animal feeding operations (CAFO). In this study we characterized XbaI-digested genomic DNA from Salmonella enterica using pulsed-field gel electrophoresis (PFGE). The PFGE analysis was conducted using 182 S. enterica isolates collected from a single CAFO between 2009 and 2012. Samples collected in 2012 were subjected to antimicrobial susceptibility testing. The analysis was limited to S. enterica serotypes, with at least 10 isolates, known to occur in both European starlings (Sturnus vulgaris) and cattle (Bos taurus) within this CAFO. A total of five different serotypes were screened; S. Anatum, S. Kentucky, S. Meleagridis, S. Montevideo, S. Muenchen. These samples were recovered from five different sample types; starling gastrointestinal tracts (GI), starling external wash, cattle feces, cattle feed and cattle water troughs. Indistinguishable S. enterica PFGE profiles were recovered from isolates originating in all sample types. Antimicrobial resistance (AMR) was also associated with indistinguishable S. enterica isolates recovered from all samples types. These data suggests that AMR S. enterica is transmitted between cattle and starlings and that shared feed sources are likely contributing to infections within both species. Moreover we isolated indistinguishable PFGE profiles across all years of data collection, suggesting long-term environmental persistence may be mediated by starling visits to CAFO. PMID:25866128

  17. Salmonella enterica flagellin is recognized via FLS2 and activates PAMP-triggered immunity in Arabidopsis thaliana.

    PubMed

    Garcia, Ana Victoria; Charrier, Amélie; Schikora, Adam; Bigeard, Jean; Pateyron, Stephanie; de Tauzia-Moreau, Marie-Ludivine; Evrard, Alexandre; Mithöfer, Axel; Martin-Magniette, Marie Laure; Virlogeux-Payant, Isabelle; Hirt, Heribert

    2014-04-01

    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 Arabidopsis thaliana, which induces PAMP-triggered immunity (PTI) via the recognition of the flg22 domain by the receptor kinase FLS2. The Arabidopsis fls2 mutant shows reduced though not abolished PTI activation, indicating that plants rely also on recognition of other S. enterica PAMPs. Interestingly, the S. enterica type III secretion system (T3SS) mutant prgH- induced stronger defense gene expression than wild-type bacteria in Arabidopsis, suggesting that T3SS effectors are involved in defense suppression. Furthermore, we observe that S. enterica strains show variation in the flg22 epitope, which results in proteins with reduced PTI-inducing activity. Altogether, these results show that S. enterica activates PTI in Arabidopsis and suggest that, in order to accomplish plant colonization, S. enterica evolved strategies to avoid or suppress PTI. PMID:24198231

  18. The structural elucidation of the Salmonella enterica subsp. enterica, reveals that it contains both O-factors 4 and 5 on the LPS antigen.

    PubMed

    De Castro, Cristina; Lanzetta, Rosa; Leone, Serena; Parrilli, Michelangelo; Molinaro, Antonio

    2013-04-01

    Spectroscopic investigation of the O-antigen from Salmonella enterica subsp. enterica revealed fine details on the acetylation pattern, the biological repeating unit and the polymerization degree. Acetylation at O-2 of the abequose residue, defined both O-factors 4 and 5 in the O-antigen chain of the lipopolysaccharide. NMR observation of the terminal non-reducing end of the polymer confirmed previous data regarding the biological repeating unit and showed an average polymerization degree of 5. The information about these structural elements might contribute to the understanding of key features of the biology of this pathogen, as phase variation and/or adaptation to the external environment. PMID:23419941

  19. Virulence Gene Regulation by l-Arabinose in Salmonella enterica

    PubMed Central

    López-Garrido, Javier; Puerta-Fernández, Elena; Cota, Ignacio; Casadesús, Josep

    2015-01-01

    Invasion of the intestinal epithelium is a critical step in Salmonella enterica infection and requires functions encoded in the gene cluster known as Salmonella Pathogenicity Island 1 (SPI-1). Expression of SPI-1 genes is repressed by l-arabinose, and not by other pentoses. Transport of l-arabinose is necessary to repress SPI-1; however, repression is independent of l-arabinose metabolism and of the l-arabinose-responsive regulator AraC. SPI-1 repression by l-arabinose is exerted at a single target, HilD, and the mechanism appears to be post-translational. As a consequence of SPI-1 repression, l-arabinose reduces translocation of SPI-1 effectors to epithelial cells and decreases Salmonella invasion in vitro. These observations reveal a hitherto unknown role of l-arabinose in gene expression control and raise the possibility that Salmonella may use L-arabinose as an environmental signal. PMID:25991823

  20. Gene Transfer between Salmonella enterica Serovar Typhimurium inside Epithelial Cells

    PubMed Central

    Ferguson, Gayle C.; Heinemann, Jack A.; Kennedy, Martin A.

    2002-01-01

    Virulence and antibiotic resistance genes transfer between bacteria by bacterial conjugation. Conjugation also mediates gene transfer from bacteria to eukaryotic organisms, including yeast and human cells. Predicting when and where genes transfer by conjugation could enhance our understanding of the risks involved in the release of genetically modified organisms, including those being developed for use as vaccines. We report here that Salmonella enterica serovar Typhimurium conjugated inside cultured human cells. The DNA transfer from donor to recipient bacteria was proportional to the probability that the two types of bacteria occupied the same cell, which was dependent on viable and invasive bacteria and on plasmid tra genes. Based on the high frequencies of gene transfer between bacteria inside human cells, we suggest that such gene transfers occur in situ. The implications of gene transfer between bacteria inside human cells, particularly in the context of antibiotic resistance, are discussed. PMID:11914355

  1. Osteomyelitis caused by Salmonella enterica serovar derby in boa constrictor.

    PubMed

    de Souza, Suyene O; Casagrande, Renata A; Guerra, Priscila R; Cruz, Cláudio E F; Veit, Evandro; Cardoso, Marisa R I; Driemeier, David

    2014-09-01

    After demonstrating chronic weight loss, prostration, and muscle flaccidness, a captive-bred 9-mo-old boa constrictor (Boa constrictor constrictor) died and was submitted for necropsy. Along the spinal column there were multiple, yellowish white, macroscopic nodules of 1-5 mm in diameter in the ventral side of the vertebral body and in the intervertebral spaces. Severe multifocal necrotizing osteomyelitis associated with granulomatous inflammation was the main histologic finding in the vertebral column. In the liver, there was discrete but similar granulomatous changes. Positive anti-Salmonella immunostaining was observed in the spinal column and in the liver. Salmonella enterica serovar Derby was isolated from fragments of the spinal column. These bacteria are important cause of disease in captive reptiles. PMID:25314834

  2. Cytotoxic T cell adjuvant effects of three Salmonella enterica flagellins

    PubMed Central

    Braga, Catarina J.M.; Massis, Liliana M.; Alencar, Bruna C.G.; Rodrigues, Maurício M.; Sbrogio-Almeida, M.E.; Ferreira, Luís C.S.

    2008-01-01

    Bacterial flagellins are important virulence-associated factors and strong inducers of inflammatory responses in mammalian hosts. Flagellins have also been investigated as potential vaccine adjuvants, either for induction of humoral or cellular immune responses, to different target antigens. In this study we investigated the adjuvant properties of three Salmonella enterica flagellins types (FliCd, FliCi and FljB) to an ovalbumin-derived CD8+ T cell-restricted epitope (OVA257–264). Although mice immunized with the three tested flagellins elicited antigen-specific activated CD8+ T cells, only animals immunized with FliCi and FliCd flagellins admixed with ovalbumin mounted specific in vivo cytotoxic responses to peptide-pulsed target cells. The present results indicate that Salmonella flagellins are endowed with type-specific adjuvant effects toward murine CD8+ T cells, a feature that may impact their use as adjuvants for prophylatic or therapeutic vaccines. PMID:24031176

  3. Quinolone Resistance Mechanisms Among Salmonella enterica in Malaysia.

    PubMed

    Thong, Kwai Lin; Ngoi, Soo Tein; Chai, Lay Ching; Teh, Cindy Shuan Ju

    2016-06-01

    The prevalence of quinolone-resistant Salmonella enterica is on the rise worldwide. Salmonella enterica is one of the major foodborne pathogens in Malaysia. Therefore, we aim to investigate the occurrence and mechanisms of quinolone resistance among Salmonella strains isolated in Malaysia. A total of 283 Salmonella strains isolated from food, humans, and animals were studied. The disk diffusion method was used to examine the quinolone susceptibility of the strains, and the minimum inhibitory concentration (MIC) values of nalidixic acid and ciprofloxacin were also determined. DNA sequencing of the quinolone resistance-determining regions (QRDRs) of gyrase and topoisomerase IV genes and the plasmid-borne qnr genes was performed. The transfer of the qnr gene was examined through transconjugation experiment. A total of 101 nalidixic acid-resistant Salmonella strains were identified. In general, all strains were highly resistant to nalidixic acid (average MICNAL, 170 μg/ml). Resistance to ciprofloxacin was observed in 30.7% of the strains (1 ≤ MICCIP ≤ 2 μg/ml). Majority of the strains contained missense mutations in the QRDR of gyrA (69.3%). Silent mutations were frequently detected in gyrB (75.2%), parC (27.7%), and parE (51.5%) within and beyond the QRDRs. Novel mutations were detected in parC and parE. The plasmid-borne qnrS1 variant was found in 36.6% of the strains, and two strains were found to be able to transfer the qnrS1 gene. Overall, mutations in gyrA and the presence of qnrS1 genes might have contributed to the high level of quinolone resistance among the strains. Our study provided a better understanding on the status of quinolone resistance among Salmonella strains circulating in Malaysia. PMID:26683630

  4. De Novo Amino Acid Biosynthesis Contributes to Salmonella enterica Growth in Alfalfa Seedling Exudates

    PubMed Central

    Kwan, Grace; Pisithkul, Tippapha; Amador-Noguez, Daniel

    2014-01-01

    Salmonella enterica is a member of the plant microbiome. Growth of S. enterica in sprouting-seed exudates is rapid; however, the active metabolic networks essential in this environment are unknown. To examine the metabolic requirements of S. enterica during growth in sprouting-seed exudates, we inoculated alfalfa seeds and identified 305 S. enterica proteins extracted 24 h postinoculation from planktonic cells. Over half the proteins had known metabolic functions, and they are involved in over one-quarter of the known metabolic reactions. Ion and metabolite transport accounted for the majority of detected reactions. Proteins involved in amino acid transport and metabolism were highly represented, suggesting that amino acid metabolic networks may be important for S. enterica growth in association with roots. Amino acid auxotroph growth phenotypes agreed with the proteomic data; auxotrophs in amino acid-biosynthetic pathways that were detected in our screen developed growth defects by 48 h. When the perceived sufficiency of each amino acid was expressed as a ratio of the calculated biomass requirement to the available concentration and compared to growth of each amino acid auxotroph, a correlation between nutrient availability and bacterial growth was found. Furthermore, glutamate transport acted as a fitness factor during S. enterica growth in association with roots. Collectively, these data suggest that S. enterica metabolism is robust in the germinating-alfalfa environment; that single-amino-acid metabolic pathways are important but not essential; and that targeting central metabolic networks, rather than dedicated pathways, may be necessary to achieve dramatic impacts on bacterial growth. PMID:25416761

  5. Characterization of Small ColE1-Like Plasmids Conferring Kanamycin Resistance in Salmonella enterica subsp. enterica serovars Typhimurium and Newport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multi-antibiotic resistant (MR) Salmonella enterica serovars Typhimurium and Newport are an increasing concern in human and animal health. Many strains are known to carry antibiotic resistance determinants on multiple plasmids, yet detailed information is scarce. Three plasmids conferring kanamycin...

  6. Characterization of Salmonella enterica serovar Typhimurium and Salmonella enterica serovar 4,[5],12:i:- isolates from pigs presenting with diarrhea in Korea

    PubMed Central

    LEE, Ki-Eun; LEE, Deog-Yong; CHOI, Hwan-Won; CHAE, Su-Jin; YUN, Young-Sun; LEE, Ki-Chan; CHO, Yun-Sang; YANG, Dong-Kun

    2015-01-01

    Between 2011 and 2012, a total of 896 pig fecal samples were collected from nine provinces in Korea, and 50 salmonella enterica susp. enterica serovar Typhimurium (S. Typhimurium) was isolated. The characteristics of the 50 strains were analyzed, and 4 strains were identified as Salmonella enterica subsp. enterica serovar 4,[5],12:i:-. Salmonella 4,[5],12:i:- could not be distinguished from S. Typhimurium through phage typing, antimicrobial resistance testing or multiple-locus variable-number tandem repeat analysis (MLVA). However, among the four Salmonella 4,[5],12:i:- strains, one (KVCC-BA1400078) was identified as a Salmonella 4,[5],12:i:- clone isolated from humans in the United States, and another (KVCC-BA1400080) was identified as DT193, which has been primarily isolated from humans and animals in European countries. The presence of Salmonella 4,[5],12:i:- in Korea poses a significant threat of horizontal transfer between pigs and humans. PMID:26074410

  7. Gene expression analysis of Salmonella enterica Enteritidis NalR and Salmonella enterica Kentucky 3795 exposed to HCl and acetic acid in rich medium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the United States, serovar Kentucky has become one of the most frequently isolated Salmonella enterica serovars from chickens. The reasons for this prevalence are not well understood. Phenotypic comparisons of poultry Salmonella isolates belonging to various serovars demonstrated that serovar Ken...

  8. Acute Hepatic Necrosis Caused by Salmonella enterica Serotype I 4,5,12:−:1,2 in a Dog

    PubMed Central

    Meiring, Thelma; Grant, Andrew J.; Watson, Penny J.

    2015-01-01

    Acute hepatic necrosis was diagnosed in a dog. Gram staining and fluorescence in situ hybridization identified Salmonella enterica in the liver, subsequently confirmed as S. enterica serotype I 4,5,12:−:1,2. This is the first report of acute hepatic necrosis with liver failure caused by Salmonella in a dog. PMID:26292301

  9. Cross-sectional study examining Salmonella enterica carriage in subiliac lymph nodes of cull and feedlot cattle at harvest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bovine peripheral lymph nodes (LNs), including subiliac LNs, have been identified as a potential source of human exposure to Salmonella enterica, when adipose trim containing these nodes is incorporated into ground beef. In order to gain a better understanding of the burden of S. enterica in periphe...

  10. Intergenic Sequence Ribotyping using a region neighboring dkgB links genovar to Kauffman-White serotype of Salmonella enterica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Intergenic Sequence Ribotyping using a region neighboring dkgB links genovar to Kauffman-White serotype of Salmonella enterica Previous research identified that the 5S ribosomal (rrn) gene and associated flanking sequences that are closely linked to the dkgB gene of Salmonella enterica were highly ...

  11. Characterization of tetracycline resistance in Salmonella enterica strains recovered from irrigation water in the Culiacan Valley, Mexico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is one of the most important pathogens responsible for gastrointestinal infections in humans. The increase of S. enterica strains showing resistance against antibiotics has resulted in limiting the effective treatment of human infections. The present study characterized the resi...

  12. Salmonella enterica serovar Kentucky isolates from dairy cows and poultry demonstrate different evolutionary histories and host-specific polymorphisms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica serovar Kentucky is commonly isolated from dairy cows and poultry in the United States. Although it is not among the most frequently isolated serovars from cases of human salmonellosis, its high prevalence in livestock and poultry indicate it is a potential public...

  13. Effects of integrated treatment of nonthermal UV-C light and different antimicrobial wash on Salmonella enterica on plum tomatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Produce contamination by foodborne pathogens remains a serious threat. This study investigated synergistic effects of ultraviolet-C and various active sanitizers’ washes against Salmonella enterica on plum tomatoes. A bacterial cocktail containing three serotypes of Salmonella enterica (S. Newport H...

  14. Cross-sectional study examining Salmonella enterica carriage in subiliac lymph nodes of cull and feedlot cattle at harvest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bovine peripheral lymph nodes, including subiliac lymph nodes, have been identified as a potential source of human exposure to Salmonella enterica when trim containing these nodes is incorporated into ground beef. In order to gain a better understanding of the burden of S. enterica in subiliac lymp...

  15. Development of a Rapid Multiplex PCR Technique for Determination of Salmonella enterica Serotypes Isolated from Pork and Poultry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: A multiplex PCR technique to discriminate Salmonella enterica serotypes was adapted to a high-throughput, automated assay. Methods: Fifteen target genes were chosen that varied in distribution among common Salmonella enterica serotypes isolated from various hosts. These targets were dete...

  16. Analysis of antimicrobial resistance genes detected in multidrug-resistant salmonella enterica serovar typhimurium isolated from food animals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of multi drug resistance (MDR) in foodborne pathogens such as Salmonella enterica is a concern for both animal and human health. MDR Salmonella enterica serovar Typhimurium is the most prevalent penta-resistant serovar isolated from animals as part of the National Antimicrobial Resis...

  17. Occurrence of antimicrobial-resistant Escherichia coli and Salmonella enterica in the beef cattle production and processing continuum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Specific concerns have been raised that 3rd-generation cephalosporin-resistant (3GCr) Escherichia coli, trimethoprim-sulfamethoxazole-resistant (COTr) E. coli, 3GCr Salmonella enterica, and nalidixic acid-resistant (NALr) S. enterica, may be present in cattle production environments, persist through...

  18. Genomic and Phenotypic Analyses Reveal the Emergence of an Atypical Salmonella enterica Serovar Senftenberg Variant in China.

    PubMed

    Abd El Ghany, Moataz; Shi, Xiaolu; Li, Yinghui; Ansari, Hifzur R; Hill-Cawthorne, Grant A; Ho, Y S; Naeem, Raeece; Pickard, Derek; Klena, John D; Xu, Xuebing; Pain, Arnab; Hu, Qinghua

    2016-08-01

    Human infections with Salmonella enterica subspecies enterica serovar Senftenberg are often associated with exposure to poultry flocks, farm environments, or contaminated food. The recent emergence of multidrug-resistant isolates has raised public health concerns. In this study, comparative genomics and phenotypic analysis were used to characterize 14 Salmonella Senftenberg clinical isolates recovered from multiple outbreaks in Shenzhen and Shanghai, China, between 2002 and 2011. Single-nucleotide polymorphism analyses identified two phylogenetically distinct clades of S Senftenberg, designated SC1 and SC2, harboring variations in Salmonella pathogenicity island 1 (SPI-1) and SPI-2 and exhibiting distinct biochemical and phenotypic signatures. Although the two variants shared the same serotype, the SC2 isolates of sequence type 14 (ST14) harbored intact SPI-1 and -2 and hence were characterized by possessing efficient invasion capabilities. In contrast, the SC1 isolates had structural deletion patterns in both SPI-1 and -2 that correlated with an impaired capacity to invade cultured human cells and also the year of their isolation. These atypical SC1 isolates also lacked the capacity to produce hydrogen sulfide. These findings highlight the emergence of atypical Salmonella Senftenberg variants in China and provide genetic validation that variants lacking SPI-1 and regions of SPI-2, which leads to impaired invasion capacity, can still cause clinical disease. These data have identified an emerging public health concern and highlight the need to strengthen surveillance to detect the prevalence and transmission of nontyphoidal Salmonella species. PMID:27225410

  19. Real-time FRET PCR assay for Salmonella enterica serotype detection in food.

    PubMed

    Olsen, Eric V; Gibbins, Carl S; Grayson, J Kevin

    2009-09-01

    Salmonella enterica subsp. enterica serotypes are leading etiological agents of food-borne gastroenteritis. Traditional identification is laborious and time intensive. Faster molecular methods may allow early identification in contaminated food products. We developed a real-time, fluorescence resonance energy transfer hybridization probe polymerase chain reaction (PCR) assay for S. enterica serotypes on the basis of the exclusive presence of the apeE gene in Salmonella Typhimurium. Assay sensitivity for 12 S. enterica serotypes was as low as 1.87 x 10(2) genomic equivalents per milliliter. PCR efficiency was 94% and the dynamic range was linear over six orders of magnitude from 10(0) to 10(6) copies. The lower limit of detection for 12 different food matrices was between 1.5 x 10(2) and 1.5 x 10(5) CFU/mL without pre-enrichment. When combined with high-throughput automated DNA extraction, 32 food specimens were processed and assayed in less than 2 hours, allowing rapid, specific, sensitive detection of S. enterica serotypes in food products. PMID:19780376

  20. Rapid Classification and Identification of Salmonellae at the Species and Subspecies Levels by Whole-Cell Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry▿ †

    PubMed Central

    Dieckmann, Ralf; Helmuth, Reiner; Erhard, Marcel; Malorny, Burkhard

    2008-01-01

    Variations in the mass spectral profiles of multiple housekeeping proteins of 126 strains representing Salmonella enterica subsp. enterica (subspecies I), S. enterica subsp. salamae (subspecies II), S. enterica subsp. arizonae (subspecies IIIa), S. enterica subsp. diarizonae (subspecies IIIb), S. enterica subsp. houtenae (subspecies IV), and S. enterica subsp. indica (subspecies VI), and Salmonella bongori were analyzed to obtain a phylogenetic classification of salmonellae based on whole-cell matrix-assisted laser desorption ionization-time of flight mass spectrometric bacterial typing. Sinapinic acid produced highly informative spectra containing a large number of biomarkers and covering a wide molecular mass range (2,000 to 40,000 Da). Genus-, species-, and subspecies-identifying biomarker ions were assigned on the basis of available genome sequence data for Salmonella, and more than 200 biomarker peaks, which corresponded mainly to abundant and highly basic ribosomal or nucleic acid binding proteins, were selected. A detailed comparative analysis of the biomarker profiles of Salmonella strains revealed sequence variations corresponding to single or multiple amino acid changes in multiple housekeeping proteins. The resulting mass spectrometry-based bacterial classification was very comparable to the results of DNA sequence-based methods. A rapid protocol that allowed identification of Salmonella subspecies in minutes was established. PMID:18952875

  1. Efficacy of European starling control to reduce Salmonella enterica contamination in a concentrated animal feeding operation in the Texas panhandle

    PubMed Central

    2011-01-01

    Background European starlings (Sturnus vulgaris) are an invasive bird species known to cause damage to plant and animal agriculture. New evidence suggests starlings may also contribute to the maintenance and spread of diseases within livestock facilities. Identifying and mitigating the risk pathways that contribute to disease in livestock is necessary to reduce production losses and contamination of human food products. To better understand the impact starlings have on disease transmission to cattle we assessed the efficacy of starling control as a tool to reduce Salmonella enterica within a concentrated animal feeding operation. We matched a large facility, slated for operational control using DRC-1339 (3-chloro-4-methylaniline hydrochloride, also 3-chloro p-toluidine hydrochloride, 3-chloro-4-methylaniline), with a comparable reference facility that was not controlling birds. In both facilities, we sampled cattle feed, cattle water and cattle feces for S. enterica before and after starling control operations. Results Within the starling-controlled CAFO, detections of S. enterica contamination disappeared from feed bunks and substantially declined within water troughs following starling control operations. Within the reference facility, detections of S. enterica contamination increased substantially within feed bunks and water troughs. Starling control was not observed to reduce prevalence of S. enterica in the cattle herd. Following starling control operations, herd prevalence of S. enterica increased on the reference facility but herd prevalence of S. enterica on the starling-controlled CAFO stayed at pretreatment levels. Conclusions Within the starling-controlled facility detections of S. enterica disappeared from feed bunks and substantially declined within water troughs following control operations. Since cattle feed and water are obvious routes for the ingestion of S. enterica, starling control shows promise as a tool to help livestock producers manage

  2. Salmonella enterica Burden in Harvest-Ready Cattle Populations from the Southern High Plains of the United States▿

    PubMed Central

    Kunze, David J.; Loneragan, Guy H.; Platt, Tammy M.; Miller, Mark F.; Besser, Thomas E.; Koohmaraie, Mohammad; Stephens, Tyler; Brashears, Mindy M.

    2008-01-01

    Our objectives were to quantify the Salmonella enterica burdens in harvest-ready cattle and to identify specific at-risk populations of cattle most likely to harbor multiply resistant S. enterica. Hide swabs were collected in abattoirs from three cohorts of cattle (feedlot origin cattle that had achieved desirable harvest characteristics and dairy- and beef-type cows harvested because of poor productivity). Feces were collected from two cohorts housed in feedlots (cattle that had achieved desirable harvest characteristics and animals identified for salvage recovery because of poor productivity). Facilities were visited on four occasions over a 12-month period. Salmonella enterica isolates were recovered, and organisms were quantified using standard microbiological methodologies. Susceptibility to antimicrobial drugs and serotype were determined for one S. enterica isolate per sample. Salmonella enterica was recovered from 55.6% of 1,681 samples. The prevalences on hides and in feces were 69.6% and 30.3%, respectively. The concentrations of S. enterica organisms averaged (as determined by the most probable number technique) 1.82 log10/100 cm2 of hides and 0.75 log10/g of feces. None of the isolates recovered from cattle that had achieved desirable harvest characteristics were resistant to four or more drugs. For isolates recovered from animals with poor productivity characteristics, 6.5% were resistant to four or more drugs. Twenty-two serovars were identified, with the most common being Salmonella enterica serovar Anatum (25.5%), Salmonella enterica serovar Montevideo (22.2%), and Salmonella enterica serovar Cerro (12.5%). High-level resistance, i.e., resistance to four or more drugs, was clustered within a few relatively uncommon serovars. These results demonstrate that even though S. enterica isolates are readily recoverable from harvest-ready cattle, multiply resistant variants are rare and are associated with specific serovars in cattle harvested because of

  3. A case of extended spectrum beta-lactamase producing Salmonella enterica serotype paratyphi A from India.

    PubMed

    Roy, Priyamvada; Rawat, Deepti; Malik, Sonia

    2015-01-01

    Enteric fever caused by Salmonella enterica is a systemic infection with high rates of morbidity and mortality. Increasing antibiotic resistance in S. enterica has led to shift in the choice of antibiotics used against this organism from chloramphenicol and ampicillin to trimethoprim-sulfamethoxazole, fluoroquinolones, and extended-spectrum cephalosporins. Resistance to cephalosporins, due to the production of extended-spectrum beta-lactamases (ESBLs), is the cause of serious concern worldwide. So far, these enzymes have been detected in many species of the family Enterobacteriaceae including different serotypes of S. enterica. To the best of our knowledge, however, ESBL production in Salmonella Paratyphi A has not yet been reported from India. We present here a case of ESBL producing Salmonella Paratyphi A from India. This is a worrisome finding with grave clinical implications, since the dissemination of this resistance trait would further limit the therapeutic options available for the treatment of enteric fever. PMID:25673610

  4. Antimicrobial Resistance and Molecular Investigation of H2S-Negative Salmonella enterica subsp. enterica serovar Choleraesuis Isolates in China

    PubMed Central

    Li, Peng; Liang, Beibei; Li, Hao; Yang, Xiaoxia; Wang, Ligui; Hao, Rongzhang; Jia, Leili; Wu, Zhihao; Qiu, Shaofu; Song, Hongbin

    2015-01-01

    Salmonella enterica subsp. enterica serovar Choleraesuis is a highly invasive pathogen of swine that frequently causes serious outbreaks, in particular in Asia, and can also cause severe invasive disease in humans. In this study, 21 S. Choleraesuis isolates, detected from 21 patients with diarrhea in China between 2010 and 2011, were found to include 19 H2S-negative S. Choleraesuis isolates and two H2S-positive isolates. This is the first report of H2S-negative S. Choleraesuis isolated from humans. The majority of H2S-negative isolates exhibited high resistance to ampicillin, chloramphenicol, gentamicin, tetracycline, ticarcillin, and trimethoprim-sulfamethoxazole, but only six isolates were resistant to norfloxacin. In contrast, all of the isolates were sensitive to cephalosporins. Fifteen isolates were found to be multidrug resistant. In norfloxacin-resistant isolates, we detected mutations in the gyrA and parC genes and identified two new mutations in the parC gene. Pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and clustered regularly interspaced short palindromic repeat (CRISPR) analysis were employed to investigate the genetic relatedness of H2S-negative and H2S-positive S. Choleraesuis isolates. PFGE revealed two groups, with all 19 H2S-negative S. Choleraesuis isolates belonging to Group I and H2S-positive isolates belonging to Group II. By MLST analysis, the H2S-negative isolates were all found to belong to ST68 and H2S-positive isolates belong to ST145. By CRISPR analysis, no significant differences in CRISPR 1 were detected; however, one H2S-negative isolate was found to contain three new spacers in CRISPR 2. All 19 H2S-negative isolates also possessed a frame-shift mutation at position 760 of phsA gene compared with H2S-positive isolates, which may be responsible for the H2S-negative phenotype. Moreover, the 19 H2S-negative isolates have similar PFGE patterns and same mutation site in the phsA gene, these results indicated

  5. Evaluation of Two Enzyme-Linked Immunosorbent Assays for Detecting Salmonella enterica subsp. enterica Serovar Dublin Antibodies in Bulk Milk

    PubMed Central

    Veling, J.; van Zijderveld, F. G.; van Zijderveld-van Bemmel, A. M.; Schukken, Y. H.; Barkema, H. W.

    2001-01-01

    Two enzyme-linked immunosorbent assays (ELISAs) for the detecting Salmonella enterica subsp. enterica serovar Dublin antibodies in bulk milk were developed and evaluated for potential use in control programs. The ELISAs were based on either lipopolysacharide (LPS ELISA) or flagellar antigen (GP ELISA). Sensitivity was determined with 79 case herds with a wide range of clinical signs. Specificity was determined with 125 Dutch and 200 Swedish control herds. The relation between antibodies in bulk milk, antibodies in serum, and the level of milk production of individual cows was studied with 61 case herds. The optimal optical density (OD) values of the LPS ELISA and the GP ELISA were determined to be 0.2 and 0.5, respectively. The sensitivities of the LPS ELISA and the GP ELISA were 54 and 63%, respectively, with a specificity of 98% for both ELISAs with samples from the Dutch control herds. The specificities for samples from the Swedish herds were 100% for the LPS ELISA and 95% for the GP ELISA. The sensitivity of the combination of tests was 65% when samples were run in parallel, and the specificity was 100% when samples were run in series, irrespective of whether the samples came from Dutch or Swedish control herds. The variance (R2) in the OD value for bulk milk samples could be explained by the percentage of seropositive lactating cows in a herd with the LPS ELISA for 51% of the samples and with the GP ELISA for 72%. The variance in the OD value was best explained by the combination of the percentage of seropositive lactating cows in the herd and the mean log10 serum antibody titer for that herd (R2 = 62% for the LPS ELISA and R2 = 75% for the GP ELISA). Case herds more often tested negative by the ELISA with bulk milk when the percentage of seropositive lactating cows was less than 5%. It is concluded that both ELISAs with bulk milk can be used in control programs to distinguish between infected and noninfected herds. Specificity can be increased by using the

  6. The giant adhesin SiiE of Salmonella enterica.

    PubMed

    Barlag, Britta; Hensel, Michael

    2015-01-01

    Salmonella enterica is a Gram-negative, food-borne pathogen, which colonizes the intestinal tract and invades enterocytes. Invasion of polarized cells depends on the SPI1-encoded type III secretion system (T3SS) and the SPI4-encoded type I secretion system (T1SS). The substrate of this T1SS is the non-fimbrial giant adhesin SiiE. With a size of 595 kDa, SiiE is the largest protein of the Salmonella proteome and consists of 53 repetitive bacterial immunoglobulin (BIg) domains, each containing several conserved residues. As known for other T1SS substrates, such as E. coli HlyA, Ca2+ ions bound by conserved D residues within the BIg domains stabilize the protein and facilitate secretion. The adhesin SiiE mediates the first contact to the host cell and thereby positions the SPI1-T3SS to initiate the translocation of a cocktail of effector proteins. This leads to actin remodeling, membrane ruffle formation and bacterial internalization. SiiE binds to host cell apical membranes in a lectin-like manner. GlcNAc and α2-3 linked sialic acid-containing structures are ligands of SiiE. Since SiiE shows repetitive domain architecture, we propose a zipper-like binding mediated by each individual BIg domain. In this review, we discuss the characteristics of the SPI4-T1SS and the giant adhesin SiiE. PMID:25587788

  7. Salmonella enterica Serotype Choleraesuis: Epidemiology, Pathogenesis, Clinical Disease, and Treatment†

    PubMed Central

    Chiu, Cheng-Hsun; Su, Lin-Hui; Chu, Chishih

    2004-01-01

    Nontyphoid Salmonella strains are important causes of reportable food-borne infection. Among more than 2,000 serotypes, Salmonella enterica serotype Choleraesuis shows the highest predilection to cause systemic infections in humans. The most feared complication of serotype Cholearesuis bacteremia in adults is the development of mycotic aneurysm, which previously was almost uniformally fatal. The advances in diagnostic techniques, surgical care, and antimicrobial therapy have greatly improved the survival of these patients. However, the recent emergence of serotype Choleraesuis that is resistant to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, and, notably, fluoroquinolone antibiotics has aroused concern about the use of these agents for the empirical treatment of systemic infection caused by this organism. In view of the serious implications of the situation, the chain of transmission and mechanism of resistance should be carefully studied to reduce the spread of infection and threat to human health. To date, there are no vaccines available to prevent serotype Choleraesuis infections in humans. The availability, in the near future, of the genome sequence of serotype Cholearesuis will facilitate the development of effective vaccines as well as the discovery of new targets for novel antimicrobial agents. PMID:15084503

  8. Clustered Intracellular Salmonella enterica Serovar Typhimurium Blocks Host Cell Cytokinesis

    PubMed Central

    Durkin, Charlotte H.; Helaine, Sophie; Boucrot, Emmanuel

    2016-01-01

    Several bacterial pathogens and viruses interfere with the cell cycle of their host cells to enhance virulence. This is especially apparent in bacteria that colonize the gut epithelium, where inhibition of the cell cycle of infected cells enhances the intestinal colonization. We found that intracellular Salmonella enterica serovar Typhimurium induced the binucleation of a large proportion of epithelial cells by 14 h postinvasion and that the effect was dependent on an intact Salmonella pathogenicity island 2 (SPI-2) type 3 secretion system. The SPI-2 effectors SseF and SseG were required to induce binucleation. SseF and SseG are known to maintain microcolonies of Salmonella-containing vacuoles close to the microtubule organizing center of infected epithelial cells. During host cell division, these clustered microcolonies prevented the correct localization of members of the chromosomal passenger complex and mitotic kinesin-like protein 1 and consequently prevented cytokinesis. Tetraploidy, arising from a cytokinesis defect, is known to have a deleterious effect on subsequent cell divisions, resulting in either chromosomal instabilities or cell cycle arrest. In infected mice, proliferation of small intestinal epithelial cells was compromised in an SseF/SseG-dependent manner, suggesting that cytokinesis failure caused by S. Typhimurium delays epithelial cell turnover in the intestine. PMID:27185791

  9. Salmonella enterica induces and subverts the plant immune system

    PubMed Central

    García, Ana V.; Hirt, Heribert

    2014-01-01

    Infections with Salmonella enterica belong to the most prominent causes of food poisoning and infected fruits and vegetables represent important vectors for salmonellosis. Although it was shown that plants raise defense responses against Salmonella, these bacteria persist and proliferate in various plant tissues. Recent reports shed light into the molecular interaction between plants and Salmonella, highlighting the defense pathways induced and the means used by the bacteria to escape the plant immune system and accomplish colonization. It was recently shown that plants detect Salmonella pathogen-associated molecular patterns (PAMPs), such as the flagellin peptide flg22, and activate hallmarks of the defense program known as PAMP-triggered immunity (PTI). Interestingly, certain Salmonella strains carry mutations in the flg22 domain triggering PTI, suggesting that a strategy of Salmonella is to escape plant detection by mutating PAMP motifs. Another strategy may rely on the type III secretion system (T3SS) as T3SS mutants were found to induce stronger plant defense responses than wild type bacteria. Although Salmonella effector delivery into plant cells has not been shown, expression of Salmonella effectors in plant tissues shows that these bacteria also possess powerful means to manipulate the plant immune system. Altogether, these data suggest that Salmonella triggers PTI in plants and evolved strategies to avoid or subvert plant immunity. PMID:24772109

  10. Diversity and Antimicrobial Resistance of Salmonella enterica Isolates from Surface Water in Southeastern United States

    PubMed Central

    Vellidis, George; Liu, Huanli; Jay-Russell, Michele; Zhao, Shaohua; Hu, Zonglin; Wright, Anita; Elkins, Christopher A.

    2014-01-01

    A study of prevalence, diversity, and antimicrobial resistance of Salmonella enterica in surface water in the southeastern United States was conducted. A new scheme was developed for recovery of Salmonella from irrigation pond water and compared with the FDA's Bacteriological Analytical Manual (8th ed., 2014) (BAM) method. Fifty-one isolates were recovered from 10 irrigation ponds in produce farms over a 2-year period; nine Salmonella serovars were identified by pulsed-field gel electrophoresis analysis, and the major serovar was Salmonella enterica serovar Newport (S. Newport, n = 29), followed by S. enterica serovar Enteritidis (n = 6), S. enterica serovar Muenchen (n = 4), S. enterica serovar Javiana (n = 3), S. enterica serovar Thompson (n = 2), and other serovars. It is noteworthy that the PulseNet patterns of some of the isolates were identical to those of the strains that were associated with the S. Thompson outbreaks in 2010, 2012, and 2013, S. Enteritidis outbreaks in 2011 and 2013, and an S. Javiana outbreak in 2012. Antimicrobial susceptibility testing confirmed 16 S. Newport isolates of the multidrug resistant-AmpC (MDR-AmpC) phenotype, which exhibited resistance to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline (ACSSuT), and to the 1st, 2nd, and 3rd generations of cephalosporins (cephalothin, amoxicillin-clavulanic acid, and ceftriaxone). Moreover, the S. Newport MDR-AmpC isolates had a PFGE pattern indistinguishable from the patterns of the isolates from clinical settings. These findings suggest that the irrigation water may be a potential source of contamination of Salmonella in fresh produce. The new Salmonella isolation scheme significantly increased recovery efficiency from 21.2 (36/170) to 29.4% (50/170) (P = 0.0002) and streamlined the turnaround time from 5 to 9 days with the BAM method to 4 days and thus may facilitate microbiological analysis of environmental water. PMID:25107969

  11. Resident bacteria on leaves enhance survival of immigrant cells of Salmonella enterica.

    PubMed

    Poza-Carrion, Cesar; Suslow, Trevor; Lindow, Steven

    2013-04-01

    Although Salmonella enterica apparently has comparatively low epiphytic fitness on plants, external factors that would influence its ability to survive on plants after contamination would be of significance in the epidemiology of human diseases caused by this human pathogen. Viable population sizes of S. enterica applied to plants preinoculated with Pseudomonas syringae or either of two Erwinia herbicola strains was ≥10-fold higher than that on control plants that were not precolonized by such indigenous bacteria when assessed 24 to 72 h after the imposition of desiccation stress. The protective effect of P. fluorescens, which exhibited antibiosis toward S. enterica in vitro, was only ≈50% that conferred by other bacterial strains. Although S. enterica could produce small cellular aggregates after incubation on wet leaves for several days, and the cells in such aggregates were less susceptible to death upon acute dehydration than solitary cells (as determined by propidium iodide staining), most Salmonella cells were found as isolated cells when it was applied to leaves previously colonized by other bacterial species. The proportion of solitary cells of S. enterica coincident with aggregates of cells of preexisting epiphytic species that subsequently were judged as nonviable by viability staining on dry leaves was as much as 10-fold less than those that had landed on uncolonized portions of the leaf. Thus, survival of immigrant cells of S. enterica on plants appears to be strongly context dependent, and the presence of common epiphytic bacteria on plants can protect such immigrants from at least one key stress (i.e., desiccation) encountered on leaf surfaces. PMID:23506362

  12. Variable abattoir conditions affect Salmonella enterica prevalence and meat quality in swine and pork.

    PubMed

    Hurd, H S; Gailey, J K; McKean, J D; Griffith, R W

    2005-01-01

    Research suggests that abattoir holding pens pose significant Salmonella enterica risk to swine immediately preharvest. The goal of this study was to evaluate those factors related to holding that increased the prevalence of S. enterica in swine at slaughter. To accomplish this goal, we focused on holding time and flooring. Our objectives were to (1) compare Salmonella enterica prevalence among pigs held for short (15-45 min) versus long (up to 4 h) periods before slaughter; and (2) determine the impact of flooring (slatted vs. concrete) as it relates to the prevalence of S. enterica. The study consisted of seven repetitions at a large volume (11,000 head/day) Midwest abattoir. Each repetition consisted of one truck load of pigs (n = 170) sorted into one of three groups: (1) animals held for a short time (15-45 min) on solid floors (short-hold); (2) animals held for 4 +/- 0.5 h on slatted floors; and (3) animals held for 4 +/- 0.5 h on solid concrete floors. At slaughter, samples were collected from 30 pigs in each group. Cecal contents (20 mL), feces (20 g), and the ileocecal lymph node were cultured for S. enterica. Additionally, the effect of holding time on meat quality parameters (loin pH at 35 min and 6 h, color, drip loss) was evaluated for the first four replicates. The proportion of S. enterica-positive samples was highest (p < 0.05) in the cecum of pigs held on solid concrete floors (72.4%), and slightly less for pigs held on slatted floors (63.3%). Animals held for less than 45 min before slaughter demonstrated the lowest proportion of S. enterica-positive samples (52.9%). The pig prevalence, as measured by any one of the three samples being positive, was significantly different (p < 0.05) between animals held on solid floors (81%) and those animals held for 45 min or less before slaughter (69%). Meat quality, as measured by multiple parameters, was adversely affected by lack of a rest period. The mean 24-h pH was significantly lower for the short

  13. Complete genome sequence of Salmonella enterica serovar typhimurium bacteriophage SPN1S.

    PubMed

    Shin, Hakdong; Lee, Ju-Hoon; Lim, Jeong-A; Kim, Hyeryen; Ryu, Sangryeol

    2012-01-01

    To understand the interaction between the host of pathogenic Salmonella enterica serovar Typhimurium and its bacteriophage, we isolated the bacteriophage SPN1S. It is a lysogenic phage in the Podoviridae family and uses the O-antigen of lipopolysaccharides (LPS) as a host receptor. Comparative genomic analysis of phage SPN1S and the S. enterica serovar Anatum-specific phage ε15 revealed different host specificities, probably due to the low homology of host specificity-related genes. Here we report the complete circular genome sequence of S. Typhimurium-specific bacteriophage SPN1S and show the results of our analysis. PMID:22205721

  14. Acquisition of extended-spectrum cephalosporin- and colistin-resistant Salmonella enterica subsp. enterica serotype Newport by pilgrims during Hajj.

    PubMed

    Olaitan, Abiola Olumuyiwa; Dia, Ndèye Méry; Gautret, Philippe; Benkouiten, Samir; Belhouchat, Khadidja; Drali, Tassadit; Parola, Philippe; Brouqui, Philippe; Memish, Ziad; Raoult, Didier; Rolain, Jean-Marc

    2015-06-01

    Gatherings like the Hajj involving many people who travel from different parts of the world represent a risk for the acquisition and dissemination of infectious diseases. In this study, acquisition of multidrug-resistant (MDR) Salmonella spp. in 2013 Hajj pilgrims from Marseille, France, was investigated. In total, 267 rectal swabs were collected from 129 participants before their departure and after their return from the pilgrimage as well as during the pilgrimage from patients with diarrhoea. Samples were screened for the presence of Salmonella using quantitative real-time PCR and culture. Whole-genome sequencing was performed to characterise one of the isolates, and the mechanism leading to colistin resistance was investigated. Six post-Hajj samples and one sample collected during a diarrhoea episode in Hajj were positive for Salmonella by real-time PCR, with five Salmonella enterica belonging to several serotypes recovered by culture, whereas no pre-Hajj sample was positive. Two of the isolates belonged to the epidemic Newport serotype, were resistant to cephalosporins, gentamicin and colistin, and harboured the bla(CTX-M-2) gene and a 12-nucleotide deletion in the pmrB gene leading to colistin resistance. This study shows that pilgrims acquired Salmonella bacteria, including a novel MDR clone, during the Hajj pilgrimage. This calls for more improved public health surveillance during Hajj because Salmonella is one of the most common diarrhoea-causing bacteria worldwide. Therefore, returning pilgrims could disseminate MDR bacteria worldwide upon returning to their home countries. PMID:25769786

  15. Risk factors for Salmonella enterica subsp. enterica shedding by market-age pigs in French farrow-to-finish herds.

    PubMed

    Beloeil, P-A; Fravalo, P; Fablet, C; Jolly, J-P; Eveno, E; Hascoet, Y; Chauvin, C; Salvat, G; Madec, F

    2004-04-30

    Fattening-pigs carriers of Salmonella enterica are believed to be a main source of carcass and pork contamination at the later steps of the meat process. We did a prospective study in 2000-2001 in 105 French farrow-to-finish pig farms. In each farm, a batch of contemporary fattening pigs housed in the same room was followed throughout the fattening period. Salmonella shedding was assessed on environmental samples of faecal material (taken by means of pairs of gauze socks) analysed by classical bacteriological methods. 36.2% of the batches studied had at least one contaminated environmental sample and therefore were classified as Salmonella-shedding batches. Logistic regression was used to assess the association between managerial and hygiene practices and health status and the shedding risk at the end of the finishing period. Emptying the pit below the slatted floor after the previous batch of sows was removed and frequent removal of sow dung during the lactation period were protective. Presence of residual Salmonella contamination of the floor and pen partitions in the fattening rooms before loading the growing pigs also was a risk factor. The risk for Salmonella shedding at the end of the fattening period was increased when dry feed (versus wet feed) was provided during the fattening period. Lastly, Lawsonia intracellularis seroconversion and PRRSV seropositivity during the fattening period also was a risk factor for Salmonella shedding. PMID:15099720

  16. Variable Carbon Catabolism among Salmonella enterica Serovar Typhi Isolates

    PubMed Central

    Chai, Lay Ching; Kong, Boon Hong; Elemfareji, Omar Ismail; Thong, Kwai Lin

    2012-01-01

    Background Salmonella enterica serovar Typhi (S. Typhi) is strictly a human intracellular pathogen. It causes acute systemic (typhoid fever) and chronic infections that result in long-term asymptomatic human carriage. S. Typhi displays diverse disease manifestations in human infection and exhibits high clonality. The principal factors underlying the unique lifestyle of S. Typhi in its human host during acute and chronic infections remain largely unknown and are therefore the main objective of this study. Methodology/Principal Findings To obtain insight into the intracellular lifestyle of S. Typhi, a high-throughput phenotypic microarray was employed to characterise the catabolic capacity of 190 carbon sources in S. Typhi strains. The success of this study lies in the carefully selected library of S. Typhi strains, including strains from two geographically distinct areas oftyphoid endemicity, an asymptomatic human carrier, clinical stools and blood samples and sewage-contaminated rivers. An extremely low carbon catabolic capacity (27% of 190 carbon substrates) was observed among the strains. The carbon catabolic profiles appeared to suggest that S. Typhi strains survived well on carbon subtrates that are found abundantly in the human body but not in others. The strains could not utilise plant-associated carbon substrates. In addition, α-glycerolphosphate, glycerol, L-serine, pyruvate and lactate served as better carbon sources to monosaccharides in the S. Typhi strains tested. Conclusion The carbon catabolic profiles suggest that S. Typhi could survive and persist well in the nutrient depleted metabolic niches in the human host but not in the environment outside of the host. These findings serve as caveats for future studies to understand how carbon catabolism relates to the pathogenesis and transmission of this pathogen. PMID:22662115

  17. Global Genomic Epidemiology of Salmonella enterica Serovar Typhimurium DT104

    DOE PAGESBeta

    Leekitcharoenphon, Pimlapas; Hendriksen, Rene S.; Le Hello, Simon; Weill, François-Xavier; Baggesen, Dorte Lau; Jun, Se-Ran; Ussery, David W.; Lund, Ole; Crook, Derrick W.; Wilson, Daniel J.; et al

    2016-03-04

    It has been 30 years since the initial emergence and subsequent rapid global spread of multidrug-resistant Salmonella enterica serovar Typhimurium DT104 (MDR DT104). Nonetheless, its origin and transmission route have never been revealed. In this paper, we used whole-genome sequencing (WGS) and temporally structured sequence analysis within a Bayesian framework to reconstruct temporal and spatial phylogenetic trees and estimate the rates of mutation and divergence times of 315 S. Typhimurium DT104 isolates sampled from 1969 to 2012 from 21 countries on six continents. DT104 was estimated to have emerged initially as antimicrobial susceptible in ~1948 (95% credible interval [CI], 1934more » to 1962) and later became MDR DT104 in ~1972 (95% CI, 1972 to 1988) through horizontal transfer of the 13-kb Salmonella genomic island 1 (SGI1) MDR region into susceptible strains already containing SGI1. This was followed by multiple transmission events, initially from central Europe and later between several European countries. An independent transmission to the United States and another to Japan occurred, and from there MDR DT104 was probably transmitted to Taiwan and Canada. An independent acquisition of resistance genes took place in Thailand in ~1975 (95% CI, 1975 to 1990). In Denmark, WGS analysis provided evidence for transmission of the organism between herds of animals. Interestingly, the demographic history of Danish MDR DT104 provided evidence for the success of the program to eradicate Salmonella from pig herds in Denmark from 1996 to 2000. Finally, the results from this study refute several hypotheses on the evolution of DT104 and suggest that WGS may be useful in monitoring emerging clones and devising strategies for prevention of Salmonella infections.« less

  18. Stress Response of Salmonella enterica Serovar Typhimurium to Acidified Nitrite

    PubMed Central

    Mühlig, Anna; Behr, Jürgen; Scherer, Siegfried

    2014-01-01

    The antimicrobial action of the curing agent sodium nitrite (NaNO2), which is added as a preservative to raw meat products, depends on its conversion to nitric oxide and other reactive nitrogen species under acidic conditions. In this study, we used RNA sequencing to analyze the acidified-NaNO2 shock and adaptive responses of Salmonella enterica serovar Typhimurium, a frequent contaminant in raw meat, considering parameters relevant for the production of raw-cured sausages. Upon a 10-min exposure to 150 mg/liter NaNO2 in LB (pH 5.5) acidified with lactic acid, genes involved in nitrosative-stress protection, together with several other stress-related genes, were induced. In contrast, genes involved in translation, transcription, replication, and motility were downregulated. The induction of stress tolerance and the reduction of cell proliferation obviously promote survival under harsh acidified-NaNO2 stress. The subsequent adaptive response was characterized by upregulation of NsrR-regulated genes and iron uptake systems and by downregulation of genes involved in anaerobic respiratory pathways. Strikingly, amino acid decarboxylase systems, which contribute to acid tolerance, displayed increased transcript levels in response to acidified NaNO2. The induction of systems known to be involved in acid resistance indicates a nitrite-mediated increase in the level of acid stress. Deletion of cadA, which encodes lysine decarboxylase, resulted in increased sensitivity to acidified NaNO2. Intracellular pH measurements using a pH-sensitive green fluorescent protein (GFP) variant showed that the cytoplasmic pH of S. Typhimurium in LB medium (pH 5.5) is decreased upon the addition of NaNO2. This study provides the first evidence that intracellular acidification is an additional antibacterial mode of action of acidified NaNO2. PMID:25107963

  19. Global Genomic Epidemiology of Salmonella enterica Serovar Typhimurium DT104

    PubMed Central

    Hendriksen, Rene S.; Le Hello, Simon; Weill, François-Xavier; Baggesen, Dorte Lau; Jun, Se-Ran; Lund, Ole; Crook, Derrick W.; Wilson, Daniel J.; Aarestrup, Frank M.

    2016-01-01

    It has been 30 years since the initial emergence and subsequent rapid global spread of multidrug-resistant Salmonella enterica serovar Typhimurium DT104 (MDR DT104). Nonetheless, its origin and transmission route have never been revealed. We used whole-genome sequencing (WGS) and temporally structured sequence analysis within a Bayesian framework to reconstruct temporal and spatial phylogenetic trees and estimate the rates of mutation and divergence times of 315 S. Typhimurium DT104 isolates sampled from 1969 to 2012 from 21 countries on six continents. DT104 was estimated to have emerged initially as antimicrobial susceptible in ∼1948 (95% credible interval [CI], 1934 to 1962) and later became MDR DT104 in ∼1972 (95% CI, 1972 to 1988) through horizontal transfer of the 13-kb Salmonella genomic island 1 (SGI1) MDR region into susceptible strains already containing SGI1. This was followed by multiple transmission events, initially from central Europe and later between several European countries. An independent transmission to the United States and another to Japan occurred, and from there MDR DT104 was probably transmitted to Taiwan and Canada. An independent acquisition of resistance genes took place in Thailand in ∼1975 (95% CI, 1975 to 1990). In Denmark, WGS analysis provided evidence for transmission of the organism between herds of animals. Interestingly, the demographic history of Danish MDR DT104 provided evidence for the success of the program to eradicate Salmonella from pig herds in Denmark from 1996 to 2000. The results from this study refute several hypotheses on the evolution of DT104 and suggest that WGS may be useful in monitoring emerging clones and devising strategies for prevention of Salmonella infections. PMID:26944846

  20. Tetracycline promotes the expression of ten fimbrial operons in specific Salmonella enterica serovar Typhimurium isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multidrug-resistant (MDR) Salmonella is associated with increased morbidity in humans and presents an important food safety concern. Antibiotic resistance among isolates of Salmonella enterica serovar Typhimurium has become especially prevalent as over 27 per cent of isolates from humans in the Unit...

  1. Effects of Pseudomonas chlororaphis and gaseous chlorine dioxide on the survival of Salmonella enterica on tomatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Produce contamination incited by Salmonella enterica serovars on tomatoes and various outbreaks of Salmonellisis have been reported periodically. Post-harvest intervention measures applied to limit produce contamination will improve food and consumer safety. The aim of this reserach was to evaluat...

  2. Carvacrol and cinnamaldehyde inactivate antibiotic-resistant Salmonella enterica in buffer and on celery and oysters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is one of the leading causes of gastrointestinal foodborne illness. The emergence of antibiotic resistant strains of this pathogen is of concern to food processors, including the produce, poultry, and oyster industries. The objective of this research was to identify the potenti...

  3. Survival of Salmonella enterica in aerated and nonaerated wastewaters from dairy lagoons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella is the most commonly identified foodborne pathogen in produce, meat and poultry. Cattle are known reservoirs of Salmonella and the pathogen excreted in feces end up in manure flush lagoons. Salmonella enterica survival was monitored in wastewater from on-site holding lagoons equipped with...

  4. Polynucleotide phosphorlyase (PNPase) is required for Salmonella enterica serovar Typhimurium colonization in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The pnp gene encodes polynucleotide phosphorylase, an exoribonuclease involved in RNA degradation. A mutation in the pnp gene was previously identified by our group in a signature-tagged mutagenesis screen designed to search for Salmonella enterica serovar Typhimurium genes required for survival in...

  5. Draft Genome Sequences of 37 Salmonella enterica Strains Isolated from Poultry Sources in Nigeria.

    PubMed

    Useh, Nicodemus M; Ngbede, Emmanuel O; Akange, Nguavese; Thomas, Milton; Foley, Andrew; Keena, Mitchel Chan; Nelson, Eric; Christopher-Hennings, Jane; Tomita, Masaru; Suzuki, Haruo; Scaria, Joy

    2016-01-01

    Here, we report the availability of draft genomes of several Salmonella serotypes, isolated from poultry sources from Nigeria. These genomes will help to further understand the biological diversity of S. enterica and will serve as references in microbial trace-back studies to improve food safety. PMID:27151793

  6. SALMONELLA ENTERICA SEROVAR ENTERITIDIS INFECTION MODULATES DIVERSE FUNCTIONAL PROCESSES OF CHICKEN MACROPHAGE AT THE TRANSCRIPTIONAL LEVEL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Enteritidis (SE) is a major etiologic agent of non-typhoid salmonellosis. The organisms colonize adult chicken hosts without causing overt clinical signs. The immunological mechanisms underlying the silent and persistent infection of chickens by SE are not clearly underst...

  7. PORCINE DIFFERENTIAL GENE EXPRESSION IN RESPONSE TO SALMONELLA ENTERICA SEROVARS CHOLERAESUIS AND TYPHIMURIUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using suppression subtractive hybridization (SSH) and real-time PCR, an investigation of the porcine response to infection with Salmonella enterica serovars Choleraesuis (narrow host range) and Typhimurium (broad host range) revealed different transcriptional profiles. Ten genes identified by SSH a...

  8. GLOBAL TRANSCRIPTIONAL RESPONSE OF PORCINE MESENTERIC LYMPH NODES TO SALMONELLA ENTERICA SEROVAR TYPHIMURIUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonellosis is prevalent worldwide and is both a food safety and animal production problem. To understand the host transcriptional response to Salmonella enterica serovar Typhimurium, the Affymetrix GeneChip® porcine genome array was used to identify differentially expressed (DE) genes in mesente...

  9. Hypothesis: A role for the mouse as an amplifier of Salmonella enterica on-farm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The presence of the mouse in the environment of the hen has been consistently identified as a risk factor for the contamination of eggs by Salmonella enterica serovar Enteritidis (SE). To address how much risk the mouse poses for egg contamination, the spleens and intestines of mice caught on-farm f...

  10. THE POXR GENE OF SALMONELLA ENTERICA SEROVAR TYPHIMURIUM IS INVOLVED IN STRESS SURVIVAL AND SWINE COLONIZATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mutations in the poxR gene (STM4344; yjeA; poxA) of Salmonella enterica serovar Typhimurium (S. Typhimurium) have previously been shown to cause several phenotypic alterations including reduced pyruvate oxidase activity, virulence attenuation in the mouse model, and enhanced sensitivity to various ...

  11. Natural surface coating to inactivate Salmonella enterica Serovar Typhimurium and maintain quality of cherry tomatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of the present study were to investigate the effectiveness of zein-based coatings in reducing populations of Salmonella enterica serovar Typhimurium and preserving quality of cherry tomatoes. Tomatoes were inoculated with a cocktail of S. Typhimurium LT2 plus three mutants on the smoo...

  12. Hydrogen-Stimulated carbon acquisition and conservation in salmonella enterica serovar typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Typhimurium can utilize molecular hydrogen for growth and amino acid transport during anaerobic growth. Via microarray we identified H2 gas-affected gene expression changes in Salmonella. Addition of H2 caused altered expression of 965 genes; 176 genes were H2-up-regulate...

  13. Extremely Drug-Resistant Salmonella enterica Serovar Senftenberg Infections in Patients in Zambia

    PubMed Central

    Joensen, Katrine Grimstrup; Lukwesa-Musyani, Chileshe; Kalondaa, Annie; Leekitcharoenphon, Pimlapas; Nakazwe, Ruth; Aarestrup, Frank M.; Hasman, Henrik; Mwansa, James C. L.

    2013-01-01

    Two cases of extremely drug-resistant Salmonella enterica serovar Senftenberg isolated from patients in Zambia were investigated by utilizing MIC determinations and whole-genome sequencing. The isolates were resistant to, and harbored genes toward, nine drug classes, including fluoroquinolones and extended-spectrum cephalosporins, contained two plasmid replicons, and differed by 93 single-nucleotide polymorphisms. PMID:23077128

  14. Potential International Spread of Multidrug-Resistant Invasive Salmonella enterica Serovar Enteritidis

    PubMed Central

    Rodicio, M. Rosario; Guerra, Beatriz; Hopkins, Katie L.

    2012-01-01

    In developing countries, Salmonella enterica serovar Enteritidis causes substantial illness and death, and drug resistance is increasing. Isolates from the United Kingdom containing virulence-resistance plasmids were characterized. They mainly caused invasive infections in adults linked to Africa. The common features in isolates from these continents indicate the role of human travel in their spread. PMID:22709653

  15. Transcriptional Response of Chicken Macrophages to Salmonella enterica serovar Enteritidis Infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Enteritidis (SE) continues to be the predominant etiologic agent of salmonellosis, with contaminated egg products being the primary source of infection. At the present time, the molecular and immunological mechanisms involved in SE colonization of chicken hosts are not we...

  16. Osmoregulated periplasmic glucans of Salmonella enterica serovar Typhimurium are required for optimal virulence in mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We purified osmoregulated periplasmic glucans (OPGs) from Salmonella enterica serovar Typhimurium and found them to be composed of 100% glucose with 2-linked glucose as the most abundant residue with terminal glucose, 2,3-linked and 2,6-linked glucose also present in high quantities. The two structu...

  17. Inc A/C Plasmids are Prevalent in Multidrug-Resistant Salmonella enterica Isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacteria plasmids are fragments of extra-chromosomal double stranded deoxyribonucleic acid (DNA) that can contain a variety of genes beneficial to the host organism like antibiotic resistance. The objective of this study was to characterize a collection of 437 Salmonella enterica isolates from diff...

  18. Survival and fate of Salmonella enterica serovar Montevideo in adult Horn Flies (Diptera: Muscidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contamination of cattle peripheral lymph nodes with Salmonella enterica is proposed to occur via a transdermal route of entry. If so, bacteria may be introduced to cattle by biting arthropods. Biting flies, such as horn flies (Haematobia irritans irritans (L.); Diptera: Muscidae), are intriguing ca...

  19. Genomic epidemiology of Salmonella enterica serotype Enteritidis based on population structure of prevalent lineages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serotype Enteritidis (SE) is one of the most commonly reported causes of human salmonellosis. The low genetic diversity of SE measured by fingerprinting methods has made subtyping a challenge. In this study, we used whole genome sequencing to characterize a total of 125 SE and Sa...

  20. Diagnostic accuracy of rectoanal mucosal swab of feedlot cattle for detection and enumeration of Salmonella enterica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cattle are noted carriers of the foodborne pathogen Salmonella enterica. The perceived need to decrease the potential human health risk posed by excretion of this pathogen has resulted in numerous studies examining the factors that influence cattle shedding of Salmonella. Fecal grab (FG) samples hav...

  1. Inactivation of Salmonella enterica by UV-C Light Alone and in Combination with Mild Temperatures

    PubMed Central

    Gayán, E.; Serrano, M. J.; Raso, J.; Álvarez, I.

    2012-01-01

    The aim of this investigation was to study the efficacy of the combined processes of UV light and mild temperatures for the inactivation of Salmonella enterica subsp. enterica and to explore the mechanism of inactivation. The doses to inactivate the 99.99% (4D) of the initial population ranged from 18.03 (Salmonella enterica serovar Typhimurium STCC 878) to 12.75 J ml−1 (Salmonella enterica serovar Enteritidis ATCC 13076). The pH and water activity of the treatment medium did not change the UV tolerance, but it decreased exponentially by increasing the absorption coefficient. An inactivating synergistic effect was observed by applying simultaneous UV light and heat treatment (UV-H). A less synergistic effect was observed by applying UV light first and heat subsequently. UV did not damage cell envelopes, but the number of injured cells was higher after a UV-H treatment than after heating. The synergistic effect observed by combining simultaneous UV and heat treatment opens the possibility to design combined treatments for pasteurization of liquid food with high UV absorptivity, such as fruit juices. PMID:23001665

  2. Assignment of serotype to Salmonella enterica isolates obtained from poultry and their environment in Southern Brazil.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To assess diversity of Salmonella enterica serotypes present in poultry and their environment from Southern Brazil, the Kauffman-White-LeMinor (KWL) scheme was used to serotype a total of 155 isolates. Isolates were then re-examined with nested PCR and sequencing of the dkgB-linked Intergenic Sequ...

  3. Antibiotics induce the expression of attachment genes in specific isolates of Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than 27 percent of Salmonella enterica serovar Typhimurium isolates from humans in the United States are resistant to three or more antibiotics. This presents an important food safety concern as multidrug-resistant (MDR) Salmonella is associated with increased morbidity in humans. It has been...

  4. Impact of Strain Variation on the Ability of Biosensor Technology to Detect Salmonella enterica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: It is important to develop methods that can quickly and accurately detect the presence of bacteria in the food supply that cause disease. Salmonella enterica is a bacteria that is often associated with contamination of food. Strains vary in their ability to cause illness and to spread...

  5. Invasive Salmonella enterica serotype typhimurium infections, Democratic Republic of the Congo, 2007-2011.

    PubMed

    Ley, Benedikt; Le Hello, Simon; Lunguya, Octavie; Lejon, Veerle; Muyembe, Jean-Jacques; Weill, François-Xavier; Jacobs, Jan

    2014-04-01

    Infection with Salmonella enterica serotype Typhimurium sequence type (ST) 313 is associated with high rates of drug resistance, bloodstream infections, and death. To determine whether ST313 is dominant in the Democratic Republic of the Congo, we studied 180 isolates collected during 2007-2011; 96% belonged to CRISPOL type CT28, which is associated with ST313. PMID:24655438

  6. Salmonella enterica serotype enteritidis in French Polynesia, South Pacific, 2008-2013.

    PubMed

    Le Hello, Simon; Maillard, Fiona; Mallet, Henri-Pierre; Daudens, Elise; Levy, Marc; Roy, Valérie; Branaa, Philippe; Bertrand, Sophie; Fabre, Laetitia; Weill, François-Xavier

    2015-06-01

    Outbreaks of Salmonella enterica serotype Enteritidis infections associated with eggs occurred in French Polynesia during 2008-2013. Molecular analysis of isolates by using clustered regularly interspaced short palindromic repeat polymorphisms and multilocus variable-number tandem-repeat analysis was performed. This subtyping made defining the epidemic strain, finding the source, and decontaminating affected poultry flocks possible. PMID:25988406

  7. TRANSCRIPTIONAL RESPONSE OF CHICKEN MACROPHAGES TO SALMONELLA ENTERICA SEROVAR ENTERITIDIS INFECTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The transcriptional profiles of chicken macrophages (HD11) infected with Salmonella enterica serovar Enteritidis (SE) were analyzed by using avian macrophage microarray and real time RT-PCR. Out of 4,906 array elements interrogated, 269 genes exhibited a 2-fold change (P < 0.001) over a 24-hour time...

  8. Novel Surveillance of Salmonella enterica Serotype Heidelberg Epidemics in a Closed Community

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During 2003-2005, a systematic and regularly timed human and farm-animal wastewater sampling scheme existed in several prison units in Texas. In early July 2003, an outbreak of gastroenteritis caused by Salmonella enterica serotype Heidelberg occurred in the human population at one site. Wastewate...

  9. L-2,3-diaminopropionate generates diverse metabolic stresses in Salmonella enterica.

    PubMed

    Ernst, Dustin C; Anderson, Mary E; Downs, Diana M

    2016-07-01

    Unchecked amino acid accumulation in living cells has the potential to cause stress by disrupting normal metabolic processes. Thus, many organisms have evolved degradation strategies that prevent endogenous accumulation of amino acids. L-2,3-diaminopropionate (Dap) is a non-protein amino acid produced in nature where it serves as a precursor to siderophores, neurotoxins and antibiotics. Dap accumulation in Salmonella enterica was previously shown to inhibit growth by unknown mechanisms. The production of diaminopropionate ammonia-lyase (DpaL) alleviated Dap toxicity in S. enterica by catalyzing the degradation of Dap to pyruvate and ammonia. Here, we demonstrate that Dap accumulation in S. enterica elicits a proline requirement for growth and specifically inhibits coenzyme A and isoleucine biosynthesis. Additionally, we establish that the DpaL-dependent degradation of Dap to pyruvate proceeds through an unbound 2-aminoacrylate (2AA) intermediate, thus contributing to 2AA stress inside the cell. The reactive intermediate deaminase, RidA, is shown to prevent 2AA damage caused by DpaL-dependent Dap degradation by enhancing the rate of 2AA hydrolysis. The results presented herein inform our understanding of the effects Dap has on metabolism in S. enterica, and likely other organisms, and highlight the critical role played by RidA in preventing 2AA stress stemming from Dap detoxification. PMID:27010356

  10. Genome Sequence of Salmonella enterica Serovar Typhi Oral Vaccine Strain Ty21a.

    PubMed

    Xu, Deqi; Cisar, John O; Poly, Frédéric; Yang, Jinghua; Albanese, Jason; Dharmasena, Madushini; Wai, Tint; Guerry, Patricia; Kopecko, Dennis J

    2013-01-01

    Attenuated Salmonella enterica serovar Typhi strain Ty21a is an important vaccine for controlling typhoid fever and serves as an oral vector for delivering heterologous antigens. The key attenuating features of this randomly mutated strain remain in question. Genome sequencing has revealed 679 single nucleotide polymorphisms (SNPs), and will help define alterations contributing to Ty21a safety and immunogenicity. PMID:23969054

  11. Draft Genome Sequences of 37 Salmonella enterica Strains Isolated from Poultry Sources in Nigeria

    PubMed Central

    Useh, Nicodemus M.; Ngbede, Emmanuel O.; Akange, Nguavese; Thomas, Milton; Foley, Andrew; Keena, Mitchel Chan; Nelson, Eric; Christopher-Hennings, Jane; Tomita, Masaru

    2016-01-01

    Here, we report the availability of draft genomes of several Salmonella serotypes, isolated from poultry sources from Nigeria. These genomes will help to further understand the biological diversity of S. enterica and will serve as references in microbial trace-back studies to improve food safety. PMID:27151793

  12. Differences in attachment of Salmonella enterica serovars to cabbage and lettuce leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the ability of five Salmonella enterica serovars to attach to and colonize intact and cut lettuce (Iceberg, Romaine) and cabbage surfaces. Biofilm assay and attachment of Salmonella serovars to intact and cut leaves were determined. Bacterial populations of loosely and strong...

  13. Genomic analysis and Next Generation Sequencing (NGS) of MDR plasmids in Salmonella enterica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Food animals harboring Multi-Drug Resistant (MDR) Salmonella enterica are a possible source of zoonotic human infections and are a potential risk to human health. MDR genes can be transmitted in a number of ways including via plasmids. MDR plasmid prevalence and distribution was investigated by stud...

  14. PRESENCE OF ANTIBIOTIC RESISTANT GENES IN SALMONELLA ENTERICA SEROTYPE UGANDA ISLOATES FROM 1997-2000

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the poultry and meat industry, Salmonella enterica serotype Uganda is rarely isolated in the environment. However, recent reports from veterinary diagnostic laboratories indicate an increased frequency of recovery of S. Uganda. Between 1997 and 2000, the animal arm of the National Antimicrobial...

  15. The effect of UV radiation on survival of Salmonella enterica in dried manure dust

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Animal manure has been shown to harbor Salmonella enterica, an enteric pathogen known to be resilient to environmental stresses such as desiccation and solar UV radiation. In farm settings, it has been observed that unintended aerosolization could occur when manure becomes dehydrated, ...

  16. Draft Whole-Genome Sequences of 25 Salmonella enterica Strains Representing 24 Serovars

    PubMed Central

    Brumwell, Stephanie L.; Lingohr, Erika J.; Ahmad, Aaminah; Blimkie, Travis M.; Kogan, Benjamin A.; Pilsworth, Jessica; Rehman, Muhammad A.; Schleicher, Krista L.; Shanmugaraj, Jenitta; Kropinski, Andrew M.; Nash, John H. E.

    2016-01-01

    We report the draft genome sequences of 25 Salmonella enterica strains representing 24 different serotypes, many of which were not available in public repositories during our selection process. These draft genomes will provide useful reference for the genetic variation between serotypes and aid in the development of molecular typing tools. PMID:26941156

  17. Rapid Molecular Determination of Serotype from Clinical Isolates of Salmonella Enterica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: The conventional serotyping of Salmonella Enterica is time consuming, costly, and requires highly skilled staff. In the present study, we report a multiplex PCR typing method using capillary electrophoresis for fragment analysis that allows for the identification of the 30 most common h...

  18. Differential attachment to and subsequent contamination of agricultural crops by Salmonella enterica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    U.S. salmonellosis outbreaks have occurred following consumption of tomato and cantaloupe but not lettuce. We report differential contamination among agricultural seedlings by Salmonella enterica via soil. Members of the family Brassicaceae had a higher incidence of outbreak than carrot, lettuce, an...

  19. Emergence of Ciprofloxacin-Resistant Salmonella enterica Serovar Typhi in Italy

    PubMed Central

    García-Fernández, Aurora; Gallina, Silvia; Owczarek, Slawomir; Dionisi, Anna Maria; Benedetti, Ildo; Decastelli, Lucia; Luzzi, Ida

    2015-01-01

    In developed countries, typhoid fever is often associated with persons who travel to endemic areas or immigrate from them. Typhoid fever is a systemic infection caused by Salmonella enterica serovar Typhi. Because of the emergence of antimicrobial resistance to standard first-line drugs, fluoroquinolones are the drugs of choice. Resistance to ciprofloxacin by this Salmonella serovar represents an emerging public health issue. Two S. enterica ser. Typhi strains resistant to ciprofloxacin (CIP) were reported to the Italian surveillance system for foodborne and waterborne diseases (EnterNet-Italia) in 2013. The strains were isolated from two Italian tourists upon their arrival from India. A retrospective analysis of 17 other S. enterica ser. Typhi strains isolated in Italy during 2011–2013 was performed to determine their resistance to CIP. For this purpose, we assayed for susceptibility to antimicrobial agents and conducted PCR and nucleotide sequence analyses. Moreover, all strains were typed using pulsed-field gel electrophoresis to evaluate possible clonal relationships. Sixty-eight percent of the S. enterica ser. Typhi strains were resistant to CIP (MICs, 0.125–16 mg/L), and all isolates were negative for determinants of plasmid-mediated quinolone resistance. Analysis of sequences encoding DNA gyrase and topoisomerase IV subunits revealed mutations in gyrA, gyrB, and parC. Thirteen different clonal groups were detected, and the two CIP-resistant strains isolated from the individuals who visited India exhibited the same PFGE pattern. Because of these findings, the emergence of CIP-resistant S. enterica ser. Typhi isolates in Italy deserves attention, and monitoring antibiotic susceptibility is important for efficiently managing cases of typhoid fever. PMID:26121266

  20. Emergence of Ciprofloxacin-Resistant Salmonella enterica Serovar Typhi in Italy.

    PubMed

    García-Fernández, Aurora; Gallina, Silvia; Owczarek, Slawomir; Dionisi, Anna Maria; Benedetti, Ildo; Decastelli, Lucia; Luzzi, Ida

    2015-01-01

    In developed countries, typhoid fever is often associated with persons who travel to endemic areas or immigrate from them. Typhoid fever is a systemic infection caused by Salmonella enterica serovar Typhi. Because of the emergence of antimicrobial resistance to standard first-line drugs, fluoroquinolones are the drugs of choice. Resistance to ciprofloxacin by this Salmonella serovar represents an emerging public health issue. Two S. enterica ser. Typhi strains resistant to ciprofloxacin (CIP) were reported to the Italian surveillance system for foodborne and waterborne diseases (EnterNet-Italia) in 2013. The strains were isolated from two Italian tourists upon their arrival from India. A retrospective analysis of 17 other S. enterica ser. Typhi strains isolated in Italy during 2011-2013 was performed to determine their resistance to CIP. For this purpose, we assayed for susceptibility to antimicrobial agents and conducted PCR and nucleotide sequence analyses. Moreover, all strains were typed using pulsed-field gel electrophoresis to evaluate possible clonal relationships. Sixty-eight percent of the S. enterica ser. Typhi strains were resistant to CIP (MICs, 0.125-16 mg/L), and all isolates were negative for determinants of plasmid-mediated quinolone resistance. Analysis of sequences encoding DNA gyrase and topoisomerase IV subunits revealed mutations in gyrA, gyrB, and parC. Thirteen different clonal groups were detected, and the two CIP-resistant strains isolated from the individuals who visited India exhibited the same PFGE pattern. Because of these findings, the emergence of CIP-resistant S. enterica ser. Typhi isolates in Italy deserves attention, and monitoring antibiotic susceptibility is important for efficiently managing cases of typhoid fever. PMID:26121266

  1. Assignment of serotype to Salmonella enterica isolates obtained from poultry and their environment in southern Brazil

    PubMed Central

    Pulido-Landínez, M; Sánchez-Ingunza, R; Guard, J; do Nascimento, V Pinheiro

    2013-01-01

    To assess diversity of Salmonella enterica serotypes present in poultry and their environment from southern Brazil, the Kauffmann–White–Le Minor (KWL) scheme was used to serotype a total of 155 isolates. Isolates were then re-examined with nested PCR and sequencing of the dkgB-linked intergenic sequence ribotyping (ISR) region that assesses single nucleotide polymorphisms occurring around a 5S ribosomal gene. Serotypes identified were Heidelberg (40·6%), Enteritidis (34·2%), Hadar (8·4%), Typhimurium (3·9%), Gallinarum (3·2%), Agona (1·3%), Cerro (1·3%), Livingstone (1·3%), Infantis (0·6%), Isangi (0·6%), Mbandaka (0·6%), Montevideo (0·6%) and Senftenberg (0·6%). Three unique ISRs were detected from four strains. Day old chicks yielded only S. Enteritidis, whereas S. Heidelberg was most often associated with poultry carcasses. Overall agreement between KWL and ISR was 85·2%, with disagreement possibly due to the ability of ISR to detect mixtures of serotypes in culture. Overall, ISR provided more information than did KWL about the ecology of Salm. enterica on-farm. The O-antigen group D Salm. enterica serovars such as Pullorum, Gallinarum and Enteritidis appear susceptible to overgrowth by other serotypes. Significance and Impact of the Study Single nucleotide polymorphisms found in a group of poultry-associated Salmonella isolates from southern Brazil provided evidence of mixtures of serovar group D serotypes on-farm and in single samples from birds. This finding suggests that co-infection and interserotype competition of Salmonella enterica in poultry could impact the incidence of disease in animals or humans. In addition, unique serotypes were identified on-farm that escaped characterization by antibody typing. Application of cost-efficient and highly discriminatory genomic methods for assigning serotype may alter concepts about the epidemiology of Salm. enterica on-farm and in foods. PMID:23734786

  2. Metabolic parameters linked by Phenotype MicroArray to acid resistance profiles of poultry-associated Salmonella enterica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phenotype microarrays were analyzed for 51 datasets derived from Salmonella enterica. The top 4 serovars associated with poultry products and one associated with turkey, respectively Typhimurium, Enteritidis, Heidelberg, Infantis and Senftenberg, were represented. Datasets were clustered into two ...

  3. Characteristics of Salmonella enterica Serovar 4,[5],12:i:- as a Monophasic Variant of Serovar Typhimurium

    PubMed Central

    Ido, Noriko; Lee, Ken-ichi; Iwabuchi, Kaori; Izumiya, Hidemasa; Uchida, Ikuo; Kusumoto, Masahiro; Iwata, Taketoshi; Ohnishi, Makoto; Akiba, Masato

    2014-01-01

    Salmonella enterica subspecies enterica serovar 4,[5],12:i:- (S. 4,[5]12:i:-) is believed to be a monophasic variant of S. enterica serovar Typhimurium (S. Typhimurium). This study was conducted to corroborate this hypothesis and to identify the molecular and phenotypic characteristics of the S. 4,[5]12:i:- isolates in Japan. A total of 51 S. 4,[5]12:i:- isolates derived from humans, cattle, swine, chickens, birds, meat (pork), and river water in 15 prefectures in Japan between 2000 and 2010 were analyzed. All the S. 4,[5],12:i:- isolates were identified as S. Typhimurium by two different polymerase chain reactions (PCR) for identification of S. Typhimurium. Of the 51 S. 4,[5],12:i:- isolates, 39 (76.5%) harbored a 94-kb virulence plasmid, which is known to be specific for S. Typhimurium. These data suggest that the S. 4,[5],12:i:- isolates are monophasic variants of S. Typhimurium. The flagellar phase variation is induced by three adjacent genes (fljA, fljB, and hin) in the chromosome. The results of PCR mapping of this region and comparative genomic hybridization analysis suggested that the deletion of the fljAB operon and its flanking region was the major genetic basis of the monophasic phenotype of S. 4,[5],12:i:-. The fljAB operon and hin gene were detectable in eight of the S. 4,[5],12:i:- isolates with common amino acid substitutions of A46T in FljA and R140L in Hin. The introduction of these mutations into S. Typhimurium isolates led to the loss of selectability of isolates expressing the phase 2 H antigen. These data suggested that a point mutation was the genetic basis, at least in part, of the S. 4,[5],12:i:- isolates. The results of phenotypic analysis suggested that the S. 4,[5],12:i:- isolates in Japan consist of multiple distinct clones. This is the first detailed characterization of the S. 4,[5],12:i:- isolates derived from various sources across Japan. PMID:25093666

  4. Analysis of Molecular Epidemiology of Chilean Salmonella enterica Serotype Enteritidis Isolates by Pulsed-Field Gel Electrophoresis and Bacteriophage Typing

    PubMed Central

    Fernandez, Jorge; Fica, Alberto; Ebensperger, German; Calfullan, Hector; Prat, Soledad; Fernandez, Alda; Alexandre, Marcela; Heitmann, Ingrid

    2003-01-01

    Human Salmonella enterica serotype Enteritidis infections emerged in Chile in 1994. S. enterica serotype Enteritidis phage type 1 isolates predominated in the north, and phage type 4 isolates predominated in the central and southern regions. A study was planned to characterize this epidemic using the best discriminatory typing technique. Research involved 441 S. enterica serotype Enteritidis isolates, including clinical preepidemic samples (n = 74; 1975 to 1993) and epidemic (n = 199), food (n = 72), poultry (n = 57), and some Latin American (n = 39) isolates. The best method was selected based on a sample of preepidemic isolates, analyzing the discriminatory power (DP) obtained by phage typing and randomly amplified polymorphic DNA and pulsed-field gel electophoresis (PFGE) analysis. The highest DP was associated with BlnI PFGE-bacteriophage typing analysis (0.993). A total of 38 BlnI patterns (B patterns) were identified before the epidemic period, 19 since 1994, and only 4 in both periods. Two major clusters were identified by phylogenetic analysis, and the predominant B patterns clustered in the same branch. Combined analysis revealed that specific B pattern-phage type combinations (subtypes) disappeared before 1994, that different genotypes associated with S. enterica serotype Enteritidis phage type 4 had been observed since 1988, and that strain diversity increased before the expansion of S. enterica serotype Enteritidis in 1994. Predominant subtype B3-phage type 4 was associated with the central and southern regions, and subtype B38-phage type 1 was associated with the north (P < 0.0001). Food and poultry isolates matched the predominant S. enterica serotype Enteritidis subtypes, but isolates identified in neighboring countries (Peru and Bolivia) did not match S. enterica serotype Enteritidis subtypes identified in the north of Chile. The results of this work demonstrate that genetic diversity, replacement, and expansion of specific S. enterica serotype

  5. Salmonella enterica Suppresses Pectobacterium carotovorum subsp. carotovorum Population and Soft Rot Progression by Acidifying the Microaerophilic Environment

    PubMed Central

    Kwan, Grace; Charkowski, Amy O.; Barak, Jeri D.

    2013-01-01

    ABSTRACT Although enteric human pathogens are usually studied in the context of their animal hosts, a significant portion of their life cycle occurs on plants. Plant disease alters the phyllosphere, leading to enhanced growth of human pathogens; however, the impact of human pathogens on phytopathogen biology and plant health is largely unknown. To characterize the interaction between human pathogens and phytobacterial pathogens in the phyllosphere, we examined the interactions between Pectobacterium carotovorum subsp. carotovorum and Salmonella enterica or Escherichia coli O157:H7 with regard to bacterial populations, soft rot progression, and changes in local pH. The presence of P. carotovorum subsp. carotovorum enhanced the growth of both S. enterica and E. coli O157:H7 on leaves. However, in a microaerophilic environment, S. enterica reduced P. carotovorum subsp. carotovorum populations and soft rot progression by moderating local environmental pH. Reduced soft rot was not due to S. enterica proteolytic activity. Limitations on P. carotovorum subsp. carotovorum growth, disease progression, and pH elevation were not observed on leaves coinoculated with E. coli O157:H7 or when leaves were coinoculated with S. enterica in an aerobic environment. S. enterica also severely undermined the relationship between the phytobacterial population and disease progression of a P. carotovorum subsp. carotovorum budB mutant defective in the 2,3-butanediol pathway for acid neutralization. Our results show that S. enterica and E. coli O157:H7 interact differently with the enteric phytobacterial pathogen P. carotovorum subsp. carotovorum. S. enterica inhibition of soft rot progression may conceal a rapidly growing human pathogen population. Whereas soft rotted produce can alert consumers to the possibility of food-borne pathogens, healthy-looking produce may entice consumption of contaminated vegetables. PMID:23404399

  6. Analysis of molecular epidemiology of Chilean Salmonella enterica serotype enteritidis isolates by pulsed-field gel electrophoresis and bacteriophage typing.

    PubMed

    Fernandez, Jorge; Fica, Alberto; Ebensperger, German; Calfullan, Hector; Prat, Soledad; Fernandez, Alda; Alexandre, Marcela; Heitmann, Ingrid

    2003-04-01

    Human Salmonella enterica serotype Enteritidis infections emerged in Chile in 1994. S. enterica serotype Enteritidis phage type 1 isolates predominated in the north, and phage type 4 isolates predominated in the central and southern regions. A study was planned to characterize this epidemic using the best discriminatory typing technique. Research involved 441 S. enterica serotype Enteritidis isolates, including clinical preepidemic samples (n = 74; 1975 to 1993) and epidemic (n = 199), food (n = 72), poultry (n = 57), and some Latin American (n = 39) isolates. The best method was selected based on a sample of preepidemic isolates, analyzing the discriminatory power (DP) obtained by phage typing and randomly amplified polymorphic DNA and pulsed-field gel electophoresis (PFGE) analysis. The highest DP was associated with BlnI PFGE-bacteriophage typing analysis (0.993). A total of 38 BlnI patterns (B patterns) were identified before the epidemic period, 19 since 1994, and only 4 in both periods. Two major clusters were identified by phylogenetic analysis, and the predominant B patterns clustered in the same branch. Combined analysis revealed that specific B pattern-phage type combinations (subtypes) disappeared before 1994, that different genotypes associated with S. enterica serotype Enteritidis phage type 4 had been observed since 1988, and that strain diversity increased before the expansion of S. enterica serotype Enteritidis in 1994. Predominant subtype B3-phage type 4 was associated with the central and southern regions, and subtype B38-phage type 1 was associated with the north (P < 0.0001). Food and poultry isolates matched the predominant S. enterica serotype Enteritidis subtypes, but isolates identified in neighboring countries (Peru and Bolivia) did not match S. enterica serotype Enteritidis subtypes identified in the north of Chile. The results of this work demonstrate that genetic diversity, replacement, and expansion of specific S. enterica serotype

  7. Survival of Salmonella enterica in poultry feed is strain dependent

    PubMed Central

    Andino, Ana; Pendleton, Sean; Zhang, Nan; Chen, Wei; Critzer, Faith; Hanning, Irene

    2014-01-01

    Feed components have low water activity, making bacterial survival difficult. The mechanisms of Salmonella survival in feed and subsequent colonization of poultry are unknown. The purpose of this research was to compare the ability of Salmonella serovars and strains to survive in broiler feed and to evaluate molecular mechanisms associated with survival and colonization by measuring the expression of genes associated with colonization (hilA, invA) and survival via fatty acid synthesis (cfa, fabA, fabB, fabD). Feed was inoculated with 1 of 15 strains of Salmonella enterica consisting of 11 serovars (Typhimurium, Enteriditis, Kentucky, Seftenburg, Heidelberg, Mbandanka, Newport, Bairely, Javiana, Montevideo, and Infantis). To inoculate feed, cultures were suspended in PBS and survival was evaluated by plating samples onto XLT4 agar plates at specific time points (0 h, 4 h, 8 h, 24 h, 4 d, and 7 d). To evaluate gene expression, RNA was extracted from the samples at the specific time points (0, 4, 8, and 24 h) and gene expression measured with real-time PCR. The largest reduction in Salmonella occurred at the first and third sampling time points (4 h and 4 d) with the average reductions being 1.9 and 1.6 log cfu per g, respectively. For the remaining time points (8 h, 24 h, and 7 d), the average reduction was less than 1 log cfu per g (0.6, 0.4, and 0.6, respectively). Most strains upregulated cfa (cyclopropane fatty acid synthesis) within 8 h, which would modify the fluidity of the cell wall to aid in survival. There was a weak negative correlation between survival and virulence gene expression indicating downregulation to focus energy on other gene expression efforts such as survival-related genes. These data indicate the ability of strains to survive over time in poultry feed was strain dependent and that upregulation of cyclopropane fatty acid synthesis and downregulation of virulence genes were associated with a response to desiccation stress. PMID:24570467

  8. Effects of norspermidine and spermidine on biofilm formation by potentially pathogenic Escherichia coli and Salmonella enterica wild-type strains.

    PubMed

    Nesse, Live L; Berg, Kristin; Vestby, Lene K

    2015-03-01

    Polyamines are present in all living cells. In bacteria, polyamines are involved in a variety of functions, including biofilm formation, thus indicating that polyamines may have potential in the control of unwanted biofilm. In the present study, the effects of the polyamines norspermidine and spermidine on biofilms of 10 potentially pathogenic wild-type strains of Escherichia coli serotype O103:H2, Salmonella enterica subsp. enterica serovar Typhimurium, and S. enterica serovar Agona were investigated. We found that exogenously supplied norspermidine and spermidine did not mediate disassembly of preformed biofilm of any of the E. coli and S. enterica strains. However, the polyamines did affect biofilm production. Interestingly, the two species reacted differently to the polyamines. Both polyamines reduced the amount of biofilm formed by E. coli but tended to increase biofilm formation by S. enterica. Whether the effects observed were due to the polyamines specifically targeting biofilm formation, being toxic for the cells, or maybe a combination of the two, is not known. However, there were no indications that the effect was mediated through binding to exopolysaccharides, as earlier suggested for E. coli. Our results indicate that norspermidine and spermidine do not have potential as inhibitors of S. enterica biofilm. Furthermore, we found that the commercial polyamines used contributed to the higher pH of the test medium. Failure to acknowledge and control this important phenomenon may lead to misinterpretation of the results. PMID:25595767

  9. Core Proteomic Analysis of Unique Metabolic Pathways of Salmonella enterica for the Identification of Potential Drug Targets

    PubMed Central

    2016-01-01

    Background Infections caused by Salmonella enterica, a Gram-negative facultative anaerobic bacteria belonging to the family of Enterobacteriaceae, are major threats to the health of humans and animals. The recent availability of complete genome data of pathogenic strains of the S. enterica gives new avenues for the identification of drug targets and drug candidates. We have used the genomic and metabolic pathway data to identify pathways and proteins essential to the pathogen and absent from the host. Methods We took the whole proteome sequence data of 42 strains of S. enterica and Homo sapiens along with KEGG-annotated metabolic pathway data, clustered proteins sequences using CD-HIT, identified essential genes using DEG database and discarded S. enterica homologs of human proteins in unique metabolic pathways (UMPs) and characterized hypothetical proteins with SVM-prot and InterProScan. Through this core proteomic analysis we have identified enzymes essential to the pathogen. Results The identification of 73 enzymes common in 42 strains of S. enterica is the real strength of the current study. We proposed all 73 unexplored enzymes as potential drug targets against the infections caused by the S. enterica. The study is comprehensive around S. enterica and simultaneously considered every possible pathogenic strain of S. enterica. This comprehensiveness turned the current study significant since, to the best of our knowledge it is the first subtractive core proteomic analysis of the unique metabolic pathways applied to any pathogen for the identification of drug targets. We applied extensive computational methods to shortlist few potential drug targets considering the druggability criteria e.g. Non-homologous to the human host, essential to the pathogen and playing significant role in essential metabolic pathways of the pathogen (i.e. S. enterica). In the current study, the subtractive proteomics through a novel approach was applied i.e. by considering only proteins

  10. Salmonella enterica Serovar Typhimurium and Escherichia coli Contamination of Root and Leaf Vegetables Grown in Soils with Incorporated Bovine Manure

    PubMed Central

    Natvig, Erin E.; Ingham, Steven C.; Ingham, Barbara H.; Cooperband, Leslie R.; Roper, Teryl R.

    2002-01-01

    Bovine manure, with or without added Salmonella enterica serovar Typhimurium (three strains), was incorporated into silty clay loam (SCL) and loamy sand (LS) soil beds (53- by 114-cm surface area, 17.5 cm deep) and maintained in two controlled-environment chambers. The S. enterica serovar Typhimurium inoculum was 4 to 5 log CFU/g in manure-fertilized soil. The conditions in the two environmental chambers, each containing inoculated and uninoculated beds of manure-fertilized soil, simulated daily average Madison, Wis., weather conditions (hourly temperatures, rainfall, daylight, and humidity) for a 1 March or a 1 June manure application and subsequent vegetable growing seasons ending 9 August or 28 September, respectively. Core soil samples were taken biweekly from both inoculated and uninoculated soil beds in each chamber. Radishes, arugula, and carrots were planted in soil beds, thinned, and harvested. Soils, thinned vegetables, and harvested vegetables were analyzed for S. enterica serovar Typhimurium and Escherichia coli (indigenous in manure). After the 1 March manure application, S. enterica serovar Typhimurium was detected at low levels in both soils on 31 May, but not on vegetables planted 1 May and harvested 12 July from either soil. After the 1 June manure application, S. enterica serovar Typhimurium was detected in SCL soil on 7 September and on radishes and arugula planted in SCL soil on 15 August and harvested on 27 September. In LS soil, S. enterica serovar Typhimurium died at a similar rate (P ≥ 0.05) after the 1 June manure application and was less often detected on arugula and radishes harvested from this soil compared to the SCL soil. Pathogen levels on vegetables were decreased by washing. Manure application in cool (daily average maximum temperature of <10°C) spring conditions is recommended to ensure that harvested vegetables are not contaminated with S. enterica serovar Typhimurium. Manure application under warmer (daily average maximum

  11. Role of Salmonella enterica exposure in Chilean Crohn's disease patients

    PubMed Central

    Alvarez-Lobos, Manuel; Pizarro, Daniela P; Palavecino, Christian E; Espinoza, Abner; Sebastián, Valentina P; Alvarado, Juan C; Ibañez, Patricio; Quintana, Carlos; Díaz, Orlando; Kalergis, Alexis M; Bueno, Susan M

    2013-01-01

    AIM: To study the association between exposure to Salmonella enterica (SE) and Crohn’s disease (CD) and its clinical implications in Chilean patients. METHODS: Ninety-four unrelated Chilean CD patients from CAREI (Active Cohort Registry of Inflammatory Bowel Disease) presenting to a single inflammatory bowel disease (IBD) unit of a University Hospital were prospectively included in this study. A complete clinical evaluation, including smoking history, was performed at the initial visit, and all the important data of clinical evolution of CD were obtained. Blood samples from these CD patients and 88 healthy sex- and age-matched control subjects were analyzed for exposure to SE and for their NOD2/CARD15 gene status using the presence of anti-Salmonella lipopolysaccharide antibodies [immunoglobulin-G type (IgG)] and polymerase chain reaction (PCR), respectively. We also evaluated exposure to SE in 90 sex- and age-matched patients without CD, but with known smoking status (30 smokers, 30 non-smokers, and 30 former smokers). RESULTS: CD patients comprised 54 females and 40 males, aged 35.5 ± 15.2 years at diagnosis with a mean follow-up of 9.0 ± 6.8 years. CD was inflammatory in 59 patients (62.7%), stricturing in 24 (25.5%) and penetrating in 15 (15.5%). Thirty cases (31.9%) had lesions in the ileum, 29 (30.8%) had ileocolonic lesions, 32 (34.0%) had colonic lesions and 23 (24.4%) had perianal disease. Sixteen CD patients (17%) were exposed to SE compared to 15 (17%) of 88 healthy control subjects (P = 0.8). Thirty-one CD patients (32.9%) were smokers, and 7 (7.4%) were former smokers at diagnosis. In the group exposed to SE, 10 of 16 patients (62.5%) were active smokers compared to 21 of 78 patients (26.9%) in the unexposed group (P = 0.01). On the other hand, 10 of 31 smoking patients (32%) were exposed to SE compared to 5 of 56 nonsmoking patients (9%), and one of the seven former smokers (14%) (P = 0.01). In the group of 90 patients without CD, but whose

  12. Salmonella enterica Serotype Choleraesuis Infection of the Knee and Femur in a Nonbacteremic Diabetic Patient

    PubMed Central

    Sy, Alexander M.; Sandhu, Jagbir; Lenox, Theodore

    2013-01-01

    Osteoarticular infections caused by Salmonella are rare. The rates of osteomyelitis and septic arthritis due to Salmonella are estimated to be less than 1% and 0.1%-0.2%, respectively (Kato et al., 2012). Salmonella enterica serotype Choleraesuis is a nontyphoidal Salmonella, highly pathogenic in humans, usually causing septicemic disease with little or no intestinal involvement. Serotype Choleraesuis accounts for a small percentage of published studies of Salmonella infections in the United States. It is not commonly reported in joint fluid and bones in contrast to serotype Enteritidis and Typhi, where a considerable number of cases have been published. Chen et al. in Taiwan found that 21% of bacteremic patients with this infection subsequently develop focal infections such as septic arthritis, pneumonia, peritonitis, and cutaneous abscess (Chen et al., 1999, Chiu et al., 2004). In contrast, our patient presented with localized osteoarticular infection with Salmonella enterica serotype Cholerasuis, but without evidence of bacteremia. PMID:23781356

  13. Serotypes and Antimicrobial Resistance of Human Nontyphoidal Isolates of Salmonella enterica from Crete, Greece

    PubMed Central

    Maraki, Sofia; Papadakis, Ioannis S.

    2014-01-01

    We report on the serotype distribution and the antimicrobial resistance patterns to 20 different antimicrobials of 150 Salmonella enterica strains isolated from stools of diarrhoeal patients on the island of Crete over the period January 2011-December 2012. Among the S. enterica serotypes recovered, Enteritidis was the most prevalent (37.3%), followed by Typhimurium (28.7%) and Newport (8.7%). No resistance was detected to extended-spectrum cephalosporins and carbapenems. Rates of resistance to ampicillin, amoxicillin/clavulanic acid, chloramphenicol, tetracycline, and cotrimoxazole were 9.3%, 4%, 2%, 15.3%, and 8.7%, respectively. Resistance to ≥4 antibiotics was primarily observed for serotypes Typhimurium and Hadar. Enteritidis remains the predominant serotype in Crete. Although low resistance to most antimicrobials was detected, continued surveillance of susceptibility is needed due to the risk of resistance. PMID:24860606

  14. High-Throughput CRISPR Typing of Mycobacterium tuberculosis Complex and Salmonella enterica Serotype Typhimurium.

    PubMed

    Sola, Christophe; Abadia, Edgar; Le Hello, Simon; Weill, François-Xavier

    2015-01-01

    Spoligotyping was developed almost 18 years ago and still remains a popular first-lane genotyping technique to identify and subtype Mycobacterium tuberculosis complex (MTC) clinical isolates at a phylogeographic level. For other pathogens, such as Salmonella enterica, recent studies suggest that specifically designed spoligotyping techniques could be interesting for public health purposes. Spoligotyping was in its original format a reverse line-blot hybridization method using capture probes designed on "spacers" and attached to a membrane's surface and a PCR product obtained from clustered regularly interspaced short palindromic repeats (CRISPRs). Cowan et al. and Fabre et al. were the first to propose a high-throughput Spoligotyping method based on microbeads for MTC and S. enterica serotype Typhimurium, respectively. The main advantages of the high-throughput Spoligotyping techniques we describe here are their low cost, their robustness, and the existence (at least for MTC) of very large databases that allow comparisons between spoligotypes from anywhere. PMID:25981468

  15. Repeated isolation of Salmonella enterica Goverdhan, a very rare serovar, from Danish poultry surveillance samples.

    PubMed

    Pedersen, Karl; Sørensen, Gitte; Szabo, Istvan; Hächler, Herbert; Le Hello, Simon

    2014-12-01

    We report here the appearance of a very rare serovar of Salmonella, S. enterica subsp. enterica serovar Goverdhan, in routine Salmonella surveillance samples from Danish poultry production. S. Goverdhan was found on nine occasions: in one broiler breeder farm in October 2010, four broiler farms and one broiler breeder farm in June-September 2012, two broiler breeder flocks simultaneously in June 2013, and one layer flock in July 2013. The five isolates from 2012 and the three isolates from 2013 had identical pulsed-field gel electrophoresis profiles, whereas the profile of the isolate from 2010 deviated in a single band. It is the first time this serovar has been described in samples from poultry. The origin of the bacterium is still unknown, but it is suggested that it may have been a pseudo-outbreak caused by contaminated sampling material. PMID:25448451

  16. The Vi Capsular Polysaccharide Enables Salmonella enterica Serovar Typhi to Evade Microbe-Guided Neutrophil Chemotaxis

    PubMed Central

    Wangdi, Tamding; Lee, Cheng-Yuk; Spees, Alanna M.; Yu, Chenzhou; Kingsbury, Dawn D.; Winter, Sebastian E.; Hastey, Christine J.; Wilson, R. Paul

    2014-01-01

    Salmonella enterica serovar Typhi (S. Typhi) causes typhoid fever, a disseminated infection, while the closely related pathogen S. enterica serovar Typhimurium (S. Typhimurium) is associated with a localized gastroenteritis in humans. Here we investigated whether both pathogens differ in the chemotactic response they induce in neutrophils using a single-cell experimental approach. Surprisingly, neutrophils extended chemotactic pseudopodia toward Escherichia coli and S. Typhimurium, but not toward S. Typhi. Bacterial-guided chemotaxis was dependent on the presence of complement component 5a (C5a) and C5a receptor (C5aR). Deletion of S. Typhi capsule biosynthesis genes markedly enhanced the chemotactic response of neutrophils in vitro. Furthermore, deletion of capsule biosynthesis genes heightened the association of S. Typhi with neutrophils in vivo through a C5aR-dependent mechanism. Collectively, these data suggest that expression of the virulence-associated (Vi) capsular polysaccharide of S. Typhi obstructs bacterial-guided neutrophil chemotaxis. PMID:25101794

  17. Transmission of an oxygen availability signal at the Salmonella enterica serovar Typhimurium fis promoter.

    PubMed

    Cameron, Andrew D S; Kröger, Carsten; Quinn, Heather J; Scally, Isobel K; Daly, Anne J; Kary, Stefani C; Dorman, Charles J

    2013-01-01

    The nucleoid-associated protein FIS is a global regulator of gene expression and chromosome structure in Escherichia coli and Salmonella enterica. Despite the importance of FIS for infection and intracellular invasion, very little is known about the regulation of S. enterica fis expression. Under standard laboratory growth conditions, fis is highly expressed during rapid growth but is then silenced as growth slows. However, if cells are cultured in non-aerated conditions, fis expression is sustained during stationary phase. This led us to test whether the redox-sensing transcription factors ArcA and FNR regulate S. enterica fis. Deletion of FNR had no detectable effect, whereas deletion of ArcA had the unexpected effect of further elevating fis expression in stationary phase. ArcA required RpoS for induction of fis expression, suggesting that ArcA indirectly affects fis expression. Other putative regulators were found to play diverse roles: FIS acted directly as an auto-repressor (as expected), whereas CRP had little direct effect on fis expression. Deleting regions of the fis promoter led to the discovery of a novel anaerobically-induced transcription start site (Pfis-2) upstream of the primary transcription start site (Pfis-1). Promoter truncation also revealed that the shortest functional fis promoter was incapable of sustained expression. Moreover, fis expression was observed to correlate directly with DNA supercoiling in non-aerated conditions. Thus, the full-length S. enterica fis promoter region may act as a topological switch that is sensitive to stress-induced duplex destabilisation and up-regulates expression in non-aerated conditions. PMID:24358360

  18. Intermediate Susceptibility to Ciprofloxacin among Salmonella enterica Serovar Typhi Isolates in Lima, Peru

    PubMed Central

    Lejon, Veerle; Horna, Gertrudis; Astocondor, Lizeth; Vanhoof, Raymond; Bertrand, Sophie; Jacobs, Jan

    2014-01-01

    Thirty-three Salmonella enterica serovar Typhi blood isolates from Lima, Peru (2008 to 2012), were fully susceptible to trimethoprim-sulfamethoxazole, chloramphenicol, ceftriaxone, and tetracycline; 8/33 (24.2%) showed intermediate susceptibility to ciprofloxacin carrying mutations in the quinolone resistance-determining region of the gyrA gene (Ser83-Phe and Asp87-Asn) and in the gyrB gene (Ser464-Phe). PMID:24371234

  19. Multidrug-resistant Salmonella enterica serotype Typhi, Gulf of Guinea Region, Africa.

    PubMed

    Baltazar, Murielle; Ngandjio, Antoinette; Holt, Kathryn Elizabeth; Lepillet, Elodie; Pardos de la Gandara, Maria; Collard, Jean-Marc; Bercion, Raymond; Nzouankeu, Ariane; Le Hello, Simon; Dougan, Gordon; Fonkoua, Marie-Christine; Weill, François-Xavier

    2015-04-01

    We identified 3 lineages among multidrug-resistant (MDR) Salmonella enterica serotype Typhi isolates in the Gulf of Guinea region in Africa during the 2000s. However, the MDR H58 haplotype, which predominates in southern Asia and Kenya, was not identified. MDR quinolone-susceptible isolates contained a 190-kb incHI1 pST2 plasmid or a 50-kb incN pST3 plasmid. PMID:25811307

  20. Isolation and Characterization of Antimicrobial-Resistant Nontyphoidal Salmonella enterica Serovars from Imported Food Products.

    PubMed

    Bae, Dongryeoul; Kweon, Ohgew; Khan, Ashraf A

    2016-08-01

    The objective of this study was to determine antimicrobial resistance and elucidate the resistance mechanism in nontyphoidal Salmonella enterica serovars isolated from food products imported into the United States from 2011 to 2013. Food products contaminated with antimicrobial-resistant nontyphoidal S. enterica were mainly imported from Taiwan, Indonesia, Vietnam, and China. PCR, DNA sequencing, and plasmid analyses were used to characterize antimicrobial resistance determinants. Twentythree of 110 S. enterica isolates were resistant to various antimicrobial classes, including β-lactam, aminoglycoside, phenicol, glycopeptide, sulfonamide, trimethoprim, and/or fluoroquinolone antimicrobial agents. Twelve of the isolates were multidrug resistant strains. Antimicrobial resistance determinants blaTEM-1, blaCTX-M-9, blaOXA-1, tetA, tetB, tetD, dfrA1, dfrV, dhfrI, dhfrXII, drf17, aadA1, aadA2, aadA5, orfC, qnrS, and mutations of gyrA and parC were detected in one or more antimicrobial-resistant nontyphoidal S. enterica strains. Plasmid profiles revealed that 12 of the 23 antimicrobial-resistant strains harbored plasmids with incompatibility groups IncFIB, IncHI1, IncI1, IncN, IncW, and IncX. Epidemiologic and antimicrobial resistance monitoring data combined with molecular characterization of antimicrobial resistance determinants in Salmonella strains isolated from imported food products may provide information that can be used to establish or implement food safety programs to improve public health. PMID:27497122

  1. Multidrug-Resistant Salmonella enterica Serotype Typhi, Gulf of Guinea Region, Africa

    PubMed Central

    Baltazar, Murielle; Ngandjio, Antoinette; Holt, Kathryn Elizabeth; Lepillet, Elodie; Pardos de la Gandara, Maria; Collard, Jean-Marc; Bercion, Raymond; Nzouankeu, Ariane; Le Hello, Simon; Dougan, Gordon; Fonkoua, Marie-Christine

    2015-01-01

    We identified 3 lineages among multidrug-resistant (MDR) Salmonella enterica serotype Typhi isolates in the Gulf of Guinea region in Africa during the 2000s. However, the MDR H58 haplotype, which predominates in southern Asia and Kenya, was not identified. MDR quinolone-susceptible isolates contained a 190-kb incHI1 pST2 plasmid or a 50-kb incN pST3 plasmid. PMID:25811307

  2. Cadmium resistance and uptake by bacterium, Salmonella enterica 43C, isolated from industrial effluent.

    PubMed

    Khan, Zaman; Rehman, Abdul; Hussain, Syed Z; Nisar, Muhammad A; Zulfiqar, Soumble; Shakoori, Abdul R

    2016-12-01

    Cadmium resistant bacterium, isolated from industrial wastewater, was characterized as Salmonella enterica 43C on the basis of biochemical and 16S rRNA ribotyping. It is first ever reported S. enterica 43C bared extreme resistance against heavy metal consortia in order of Pb(2+)>Cd(2+)>As(3+)>Zn(2+)>Cr(6+)>Cu(2+)>Hg(2+). Cd(2+) stress altered growth pattern of the bacterium in time dependent manner. It could remove nearly 57 % Cd(2+) from the medium over a period of 8 days. Kinetic and thermodynamic studies based on various adsorption isotherm models (Langmuir and Freundlich) depicted the Cd(2+) biosorption as spontaneous, feasible and endothermic in nature. Interestingly, the bacterium followed pseudo first order kinetics, making it a good biosorbent for heavy metal ions. The S. enterica 43C Cd(2+) processivity was significantly influenced by temperature, pH, initial Cd(2+) concentration, biomass dosage and co-metal ions. FTIR analysis of the bacterium revealed the active participation of amide and carbonyl moieties in Cd(2+) adsorption confirmed by EDX analysis. Electron micrographs beckoned further surface adsorption and increased bacterial size due to intracellular Cd(2+) accumulation. An overwhelming increase in glutathione and other non-protein thiols levels played a significant role in thriving oxidative stress generated by metal cations. Presence of metallothionein clearly depicted the role of such proteins in bacterial metal resistance mechanism. The present study results clearly declare S. enterica 43C a suitable candidate for green chemistry to bioremediate environmental Cd(2+). PMID:27491862

  3. Comparative analysis of twenty-four complete aenome aequences of Salmonella enterica Serotypes Anatum, Montevideo, Typhimurium and Newport isolated from ground beef or asymptomatic cattle on farm or at harvest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica are a versatile group of bacteria with a wide range of variation in virulence potential. Complete S. enterica genome sequences available to date are primarily of strains isolated from humans or of serotypes that commonly cause human disease. To facilitate genomic ...

  4. Influence of prgH on the Persistence of Ingested Salmonella enterica in the Leafhopper Macrosteles quadrilineatus

    PubMed Central

    Dundore-Arias, José Pablo; Groves, Russell L.

    2015-01-01

    Phytophagous insects can encounter Salmonella enterica on contaminated plant surfaces and transmit externally adhered and internalized bacteria on and among leaves. Excretion of ingested S. enterica by the leafhopper Macrosteles quadrilineatus has been previously reported; however, the sites of persistence of ingested bacteria remain undetermined. Fluorescence microscopy revealed the presence and persistence of S. enterica in various organs of M. quadrilineatus fed an inoculated diet for 12 h and then moved to two consecutive noninoculated diets for a total of 48 h. Ingested S. enterica was predominantly observed in the filter chamber, midgut, and Malpighian tubules of M. quadrilineatus dissected immediately after acquisition and at 24- and 48-h post-acquisition access periods (post-AAPs). Additionally, we examined the potential roles of the Salmonella pathogenicity island 1 (SPI-1) and SPI-2 type III secretion systems (T3SSs) in the persistence and excretion of ingested S. enterica. In competition assays, a prgH mutant lacking a functional SPI-1 T3SS was recovered at significantly lower levels than the WT in insect homogenates at 24 h post-AAP, and complementation with prgH restored S. enterica persistence in M. quadrilineatus. Moreover, expression of prgH inside M. quadrilineatus was observed up to 48 post-AAP. No differences were observed between the WT and an ssaK mutant lacking a functional SPI-2 T3SS in insect homogenates or between the WT and either mutant in insect excretions. This study provides novel insight into the presence and persistence of S. enterica inside M. quadrilineatus and demonstrates that the SPI-1 T3SS influences the persistence of the pathogen in the gut of a potential vector. PMID:26150468

  5. Influence of prgH on the Persistence of Ingested Salmonella enterica in the Leafhopper Macrosteles quadrilineatus.

    PubMed

    Dundore-Arias, José Pablo; Groves, Russell L; Barak, Jeri D

    2015-09-01

    Phytophagous insects can encounter Salmonella enterica on contaminated plant surfaces and transmit externally adhered and internalized bacteria on and among leaves. Excretion of ingested S. enterica by the leafhopper Macrosteles quadrilineatus has been previously reported; however, the sites of persistence of ingested bacteria remain undetermined. Fluorescence microscopy revealed the presence and persistence of S. enterica in various organs of M. quadrilineatus fed an inoculated diet for 12 h and then moved to two consecutive noninoculated diets for a total of 48 h. Ingested S. enterica was predominantly observed in the filter chamber, midgut, and Malpighian tubules of M. quadrilineatus dissected immediately after acquisition and at 24- and 48-h post-acquisition access periods (post-AAPs). Additionally, we examined the potential roles of the Salmonella pathogenicity island 1 (SPI-1) and SPI-2 type III secretion systems (T3SSs) in the persistence and excretion of ingested S. enterica. In competition assays, a prgH mutant lacking a functional SPI-1 T3SS was recovered at significantly lower levels than the WT in insect homogenates at 24 h post-AAP, and complementation with prgH restored S. enterica persistence in M. quadrilineatus. Moreover, expression of prgH inside M. quadrilineatus was observed up to 48 post-AAP. No differences were observed between the WT and an ssaK mutant lacking a functional SPI-2 T3SS in insect homogenates or between the WT and either mutant in insect excretions. This study provides novel insight into the presence and persistence of S. enterica inside M. quadrilineatus and demonstrates that the SPI-1 T3SS influences the persistence of the pathogen in the gut of a potential vector. PMID:26150468

  6. Dissemination of antimicrobial-resistant clones of Salmonella enterica among domestic animals, wild animals, and humans.

    PubMed

    Palomo, Gonzalo; Campos, Maria Jorge; Ugarte, María; Porrero, María Concepción; Alonso, Juan Manuel; Borge, Carmen; Vadillo, Santiago; Domínguez, Lucas; Quesada, Alberto; Píriz, Segundo

    2013-02-01

    Non-typhoidal salmonellosis is an important zoonotic disease caused by Salmonella enterica. This work focuses on the identification of Salmonella enterica clonal strains which, presenting a wide distribution potential, express resistance determinants that compromise effectiveness of the antimicrobial therapy. The screening was performed on 506 Salmonella enterica isolates from animals and humans, which were characterized by serovar and phage typing, genome macrorestriction and pulsed-field gel electrophoresis, and detection of phenotypic and genotypic traits for antimicrobial resistance. A Salmonella Enteritidis strain with strong quinolone resistance is spread on three host environments carrying one of the four variants found for the GyrA protein: (1) Asp87Tyr, the major polymorphism found in 39 Salmonella isolates from human origin and six from poultry; (2) Ser83Phe, with four isolates from human origin and one from white stork (Ciconia ciconia); and (3) Asp87Asn or (4) Asp87Gly, with two isolates each from human origins. Several Salmonella Typhimurium strains that presented int1 elements and the classically associated pentaresistance (ACSSuT) phenotype were found distributed between two host environments: domestic animals and humans, domestics and wild animals, or wild fauna plus humans. This study points out the importance of monitoring gut microbiota and its antimicrobial resistance from wildlife, in parallel to livestock animals and humans, especially for animal species that are in close contact with people. PMID:23360170

  7. Effects of postharvest handling conditions on internalization and growth of Salmonella enterica in tomatoes.

    PubMed

    Zhou, Bin; Luo, Yaguang; Nou, Xiangwu; Yang, Yang; Wu, Yunpeng; Wang, Qin

    2014-03-01

    Salmonella internalization in tomatoes during postharvest handling is a major food safety concern. This study was conducted to determine the effect of immersion time, immersion depth, and temperature differential between bacterial suspension and tomato pulp on the internalization of Salmonella enterica in tomato fruits. The effect of storage temperature and duration on the survival and growth of internalized Salmonella cells was also evaluated. Overall, immersion time significantly affected the incidence and extent of S. enterica internalization (P < 0.0001), with a linear correlation between immersion time and Salmonella internalization. The depth of Salmonella internalization in tomato tissues also increased with increasing immersion time. Immersion time also significantly influenced the degree to which the temperature differential affected Salmonella internalization. With an immersion time of 2 min, the temperature differential had no significant effect on Salmonella internalization (P = 0.2536). However, with an immersion time of 15 min, a significantly larger Salmonella population became internalized in tomatoes immersed in solutions with a -30°F (-16.7°C) temperature differential. Internalized S. enterica cells persisted in the core tissues during 14 days of storage. Strain type and storage duration significantly affected (P < 0.05) both the frequency detected and the population of internalized Salmonella recovered, but storage temperatures of 55 to 70°F (12.8 to 21.1°C) did not (P > 0.05). These findings indicate the importance of preventing pathogen internalization during postharvest handling. PMID:24674426

  8. Salmonella enterica bacteraemia: a multi-national population-based cohort study

    PubMed Central

    2010-01-01

    Background Salmonella enterica is an important emerging cause of invasive infections worldwide. However, population-based data are limited. The objective of this study was to define the occurrence of S. enterica bacteremia in a large international population and to evaluate temporal and regional differences. Methods We conducted population-based laboratory surveillance for all salmonella bacteremias in six regions (annual population at risk 7.7 million residents) in Finland, Australia, Denmark, and Canada during 2000-2007. Results A total of 622 cases were identified for an annual incidence of 1.02 per 100,000 population. The incidence of typhoidal (serotypes Typhi and Paratyphi) and non-typhoidal (other serotypes) disease was 0.21 and 0.81 per 100,000/year. There was major regional and moderate seasonal and year to year variability with an increased incidence observed in the latter years of the study related principally to increasing rates of non-typhoidal salmonella bacteremias. Advancing age and male gender were significant risk factors for acquiring non-typhoidal salmonella bacteremia. In contrast, typhoidal salmonella bacteremia showed a decreasing incidence with advancing age and no gender-related excess risk. Conclusions Salmonella enterica is an important emerging pathogen and regional determinants of risk merits further investigation. PMID:20398281

  9. DISSEMINATION OF SALMONELLA ENTERICA SEQUENCE TYPES AMONG ASEAN ECONOMIC COMMUNITY COUNTRIES.

    PubMed

    Patchanee, Prapas; Boonkhot, Phacharaporn; Kittiwan, Nattinee; Tadee, Pakpoom; Chotinun, Suwit

    2015-07-01

    Food-borne illness caused by Salmonella enterica remains a public health problem and results in economic loss worldwide. With the up-coming establish- ment of the ASEAN Economic Community (AEC) allowing unrestricted move- ment of labor and goods, there is a higher risk of pathogen transmission among the AEC countries. This study characterized and investigated the spatial and temporal associations of S. enterica strains isolated in AEC countries during 1940- 2012 compared with those isolated in northern-Thailand during 2011-2013. Of the 173 S. enterica strains examined, 68 sequence types (STs) and 32 clonal complexes (CCs) were identified by multi loci sequence typing. Twenty-one strains belonged to four sequence types new to AEC countries, and they constituted only two CCs. A number of strains originated from various countries with multiple hosts, were highlighted. There was evidence of strains circulating in the AEC region well over a decade. Such information will be important in formulating biosecurity measures, as well as in educating regarding the risk of disease transmission in AEC. PMID:26867391

  10. Antibiotic Resistance in Salmonella enterica Serovar Typhimurium Associates with CRISPR Sequence Type

    PubMed Central

    DiMarzio, Michael; Shariat, Nikki; Kariyawasam, Subhashinie; Barrangou, Rodolphe

    2013-01-01

    Salmonella enterica subsp. enterica serovar Typhimurium is a leading cause of food-borne salmonellosis in the United States. The number of antibiotic-resistant isolates identified in humans is steadily increasing, suggesting that the spread of antibiotic-resistant strains is a major threat to public health. S. Typhimurium is commonly identified in a wide range of animal hosts, food sources, and environments, but little is known about the factors mediating the spread of antibiotic resistance in this ecologically complex serovar. Previously, we developed a subtyping method, CRISPR–multi-virulence-locus sequence typing (MVLST), which discriminates among strains of several common S. enterica serovars. Here, CRISPR-MVLST identified 22 sequence types within a collection of 76 S. Typhimurium isolates from a variety of animal sources throughout central Pennsylvania. Six of the sequence types were identified in more than one isolate, and we observed statistically significant differences in resistance among these sequence types to 7 antibiotics commonly used in veterinary and human medicine, such as ceftiofur and ampicillin (P < 0.05). Importantly, five of these sequence types were subsequently identified in human clinical isolates, and a subset of these isolates had identical antibiotic resistance patterns, suggesting that these subpopulations are being transmitted through the food system. Therefore, CRISPR-MVLST is a promising subtyping method for monitoring the farm-to-fork spread of antibiotic resistance in S. Typhimurium. PMID:23796925

  11. An outbreak of multidrug-resistant Salmonella enterica subsp. enterica serotype Typhimurium, DT104L linked to dried anchovy in Singapore.

    PubMed

    Ling, M L; Goh, K T; Wang, G C Y; Neo, K S; Chua, T

    2002-02-01

    Multidrug-resistant Salmonella enterica subsp. enterica serotype Typhimurium DT104L was first reported in Singapore from mid-July to mid-October 2000. Salmonella strains isolated from clinical laboratories were submitted to a reference laboratory for serotyping, phage-typing and pulsed-field gel electrophoresis (PFGE) using XbaI restriction endonuclease. An epidemiological investigation was conducted to determine the source of infection and mode of transmission using a structured questionnaire. A total of 33 cases involving mainly infants and toddlers were detected in the 3-month long outbreak. The outbreak strain was of the R-type ACGSTSu, i.e. resistant to ampicillin, chloramphenicol, gentamicin, streptomycin, tetracycline and sulphonamide. PFGE showed all isolates had an indistinguishable pattern, indicating a common source of infection. Consumption of imported dried anchovy was found to be the vehicle of transmission after adjusting for all confounding variables in the case-control study using stepwise logistic regression (OR 25.6; 95% CI 3.9-167.9; P = 0.001). Imported dried seafood should be properly processed, packed, labelled, and thoroughly cooked to prevent transmission of multidrug-resistant S. Typhimurium. PMID:11895083

  12. Identification of Key Genes in the Response to Salmonella enterica Enteritidis, Salmonella enterica Pullorum, and Poly(I:C) in Chicken Spleen and Caecum

    PubMed Central

    Sheng, Zhongwei; Dai, Aiqin; Zhai, Fei; Li, Jianchao; Xia, Mingxiu; Hua, Dengke; Xu, Lu; Wang, Hongzhi; Chen, Jing; Liu, Lu; Chen, Guohong

    2014-01-01

    Salmonella enterica Enteritidis (S. Enteritidis) and Salmonella enterica Pullorum (S. pullorum) are regarded as a threat to poultry production. This study's aim is to characterize the expression profiles in response to three different challenges and to identify infection-related genes in the chicken spleen and caecum. Groups of the Chinese chicken breed Langshan were challenged with either S. Enteritidis, S. pullorum, or poly(I:C). The concentrations of cytokines and antibodies and the Salmonella colonization level of the caecum and liver were detected in each group at 7 days postinfection. Expression microarray experiments were conducted using mRNA isolated from both spleen and caecum. Crucial differentially expressed genes (DEGs) associated with immunity were identified. Four DEGs were identified in spleen of all three challenge groups (RBM16, FAH, SOX5, and RBM9) and different four genes in caecum (SOUL, FCN2, ANLN, and ACSL1). Expression profiles were clearly different among the three challenged groups. Genes enriched in the spleen of birds infected with S. pullorum were enriched in lymphocyte proliferation related pathways, but the enriched genes in the caecum of the same group were primarily enriched in innate immunity or antibacterial responses. The DEGs that appear across all three challenge groups might represent global response factors for different pathogens. PMID:24707473

  13. Effects of Leachate from Crumb Rubber and Zinc in Green Roofs on the Survival, Growth, and Resistance Characteristics of Salmonella enterica subsp. enterica Serovar Typhimurium

    PubMed Central

    Crampton, Mollee; Ryan, Allayna; Eckert, Cori; Baker, Katherine H.

    2014-01-01

    The use of green roofs is a growing practice worldwide, particularly in densely populated areas. In an attempt to find new methods for recycling crumb rubber, incorporation of crumb rubber into artificial medium for plant growth in green roofs and similar engineered environments has become an attractive option for the recycling of waste tires. Though this approach decreases waste in landfills, there are concerns about the leaching of zinc and other heavy metals, as well as nutrient and organic compounds, into the environment. The present study analyzed the impact of leachate from crumb rubber and zinc on the growth and viability of Salmonella enterica subsp. enterica serovar Typhimurium. Zinc was chosen for further studies since it has been previously implicated with other biological functions, including biofilm formation, motility, and possible cross-resistance to antimicrobial agents. The study showed that Salmonella can colonize crumb rubber and that crumb rubber extract may provide nutrients that are usable by this bacterium. Salmonella strains with reduced susceptibility (SRS) to zinc were obtained after subculturing in increasing concentrations of zinc. The SRS exhibited differences in gene expression of flux pump genes zntA and znuA compared to that of the parent when exposed to 20 mM added zinc. In biofilm formation studies, the SRS formed less biofilm but was more motile than the parental strain. PMID:24584242

  14. Identification of bapA in Strains of Salmonella enterica subsp. enterica Isolated from Wild Animals Kept in Captivity in Sinaloa, Mexico

    PubMed Central

    López-Valenzuela, Martin; Cárcamo-Aréchiga, Nora; Cota-Guajardo, Silvia; López-Salazar, Mayra; Montiel-Vázquez, Edith

    2016-01-01

    bapA, previously named stm2689, encodes the BapA protein, which, along with cellulose and fimbriae, constitutes biofilms. Biofilms are communities of microorganisms that grow in a matrix of exopolysaccharides and may adhere to living tissues or inert surfaces. Biofilm formation is associated with the ability to persist in different environments, which contributes to the pathogenicity of several species. We analyzed the presence of bapA in 83 strains belonging to 17 serovars of Salmonella enterica subsp. enterica from wildlife in captivity at Culiacan's Zoo and Mazatlán's Aquarium. Each isolate amplified a product of 667 bp, which corresponds to the expected size of the bapA initiator, with no observed variation between different serovars analyzed. bapA gene was found to be highly conserved in Salmonella and can be targeted for the genus-specific detection of this organism from different sources. Since bapA expression improves bacterial proliferation outside of the host and facilitates resistance to disinfectants and desiccation, the survival of Salmonella in natural habitats may be favored. Thus, the risk of bacterial contamination from these animals is increased. PMID:27379195

  15. The combination of CRISPR-MVLST and PFGE provides increased discriminatory power for differentiating human clinical isolates of Salmonella enterica subsp. enterica serovar Enteritidis.

    PubMed

    Shariat, Nikki; DiMarzio, Michael J; Yin, Shuang; Dettinger, Lisa; Sandt, Carol H; Lute, James R; Barrangou, Rodolphe; Dudley, Edward G

    2013-05-01

    Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis) is a major cause of foodborne salmonellosis. Rapid, efficient and accurate methods for identification are required to track specific strains of S. Enteritidis during outbreaks of human salmonellosis. By exploiting the hypervariable nature of virulence genes and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs), we previously developed a powerful sequence-based subtyping approach, designated CRISPR-MVLST. To substantiate the applicability of CRISPR-MVLST, we analyzed a broad set of S. Enteritidis isolates collected over a six-year period. Among 141 isolates we defined 22 Enteritidis Sequence Types (ESTs), the majority of which were novel. Notably, strains exhibiting the common PFGE pattern, JEGX01.0004 (characteristic of ∼40% of S. Enteritidis isolates in the United States), were separated into twelve distinct sequence types. Conversely, isolates of EST4, the most predominant EST we observed, comprised eight different PFGE patterns. Importantly, we showed that some genotypes that were previously associated with the food supply chain at the farm level have now been identified in clinical samples. CRISPR sequence data shows subtle but distinct differences among different alleles of S. Enteritidis, suggesting that evolution of these loci occurs vertically, as opposed to previously reported evolution by spacer acquisition in other bacteria. PMID:23498194

  16. Identification of bapA in Strains of Salmonella enterica subsp. enterica Isolated from Wild Animals Kept in Captivity in Sinaloa, Mexico.

    PubMed

    Silva-Hidalgo, Gabriela; López-Valenzuela, Martin; Cárcamo-Aréchiga, Nora; Cota-Guajardo, Silvia; López-Salazar, Mayra; Montiel-Vázquez, Edith

    2016-01-01

    bapA, previously named stm2689, encodes the BapA protein, which, along with cellulose and fimbriae, constitutes biofilms. Biofilms are communities of microorganisms that grow in a matrix of exopolysaccharides and may adhere to living tissues or inert surfaces. Biofilm formation is associated with the ability to persist in different environments, which contributes to the pathogenicity of several species. We analyzed the presence of bapA in 83 strains belonging to 17 serovars of Salmonella enterica subsp. enterica from wildlife in captivity at Culiacan's Zoo and Mazatlán's Aquarium. Each isolate amplified a product of 667 bp, which corresponds to the expected size of the bapA initiator, with no observed variation between different serovars analyzed. bapA gene was found to be highly conserved in Salmonella and can be targeted for the genus-specific detection of this organism from different sources. Since bapA expression improves bacterial proliferation outside of the host and facilitates resistance to disinfectants and desiccation, the survival of Salmonella in natural habitats may be favored. Thus, the risk of bacterial contamination from these animals is increased. PMID:27379195

  17. Aneurysm of the cranial mesenteric artery as a site of carriage of Salmonella enterica subsp. enterica serovar Abortusequi in the horse.

    PubMed

    Niwa, Hidekazu; Hobo, Seiji; Kinoshita, Yuta; Muranaka, Masanori; Ochi, Akihiro; Ueno, Takanori; Oku, Kazuomi; Hariu, Kazuhisa; Katayama, Yoshinari

    2016-07-01

    Salmonella enterica subsp. enterica serovar Abortusequi is a pathogen restricted to horses. Our investigation targeted 4 draft horses (9-10 months old) kept on a Japanese farm that had suffered an outbreak of S. Abortusequi abortion. The 4 horses were suspected to be carriers of the bacterium owing to their high agglutination titers (≥1:2,560) in tube agglutination testing. The owners' on-farm observations confirmed that the horses had no apparent abnormalities, and S. Abortusequi was not isolated from their blood, rectal swabs, or sternal bone marrow fluid at antemortem investigation. However, at autopsy, all horses displayed the following: suppurative aneurysm of the cranial mesenteric artery with heavy infection with Strongylus vulgaris larvae; heavy intestinal parasitic infection with Gasterophilus intestinalis, Parascaris equorum, Anoplocephala perfoliata, and S. vulgaris; and enlargement of the systemic lymph nodes. In each case, large numbers of S. Abortusequi were isolated from the anterior mesenteric artery thrombus. The thrombus isolates harbored a single virulence plasmid, and the pulsed-field gel electrophoresis profiles of the isolates were identical not only to each other but also to those of Japanese enzootic strains of S. Abortusequi. These results reveal that parasitic aneurysms of the cranial mesenteric artery should be considered an important possible site of carriage of S. Abortusequi in horses. The results also suggest high clonality of the isolated serovar in the horse population in Japan. PMID:27271985

  18. Effects of leachate from crumb rubber and zinc in green roofs on the survival, growth, and resistance characteristics of Salmonella enterica subsp. enterica serovar Typhimurium.

    PubMed

    Crampton, Mollee; Ryan, Allayna; Eckert, Cori; Baker, Katherine H; Herson, Diane S

    2014-05-01

    The use of green roofs is a growing practice worldwide, particularly in densely populated areas. In an attempt to find new methods for recycling crumb rubber, incorporation of crumb rubber into artificial medium for plant growth in green roofs and similar engineered environments has become an attractive option for the recycling of waste tires. Though this approach decreases waste in landfills, there are concerns about the leaching of zinc and other heavy metals, as well as nutrient and organic compounds, into the environment. The present study analyzed the impact of leachate from crumb rubber and zinc on the growth and viability of Salmonella enterica subsp. enterica serovar Typhimurium. Zinc was chosen for further studies since it has been previously implicated with other biological functions, including biofilm formation, motility, and possible cross-resistance to antimicrobial agents. The study showed that Salmonella can colonize crumb rubber and that crumb rubber extract may provide nutrients that are usable by this bacterium. Salmonella strains with reduced susceptibility (SRS) to zinc were obtained after subculturing in increasing concentrations of zinc. The SRS exhibited differences in gene expression of flux pump genes zntA and znuA compared to that of the parent when exposed to 20 mM added zinc. In biofilm formation studies, the SRS formed less biofilm but was more motile than the parental strain. PMID:24584242

  19. Complete Genome Sequence of Salmonella enterica Serovar Agona Pulsed-Field Type SAGOXB.0066, Cause of a 2008 Pan-European Outbreak.

    PubMed

    McCusker, Matthew P; Hokamp, Karsten; Buckley, James F; Wall, Patrick G; Martins, Marta; Fanning, Séamus

    2014-01-01

    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. PMID:24459278

  20. A real-time PCR method for the detection of Salmonella enterica from food using a target sequence identified by comparative genomic analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A 5'-nuclease real-time PCR assay using a minor groove binding probe was developed for the detection of Salmonella enterica from food. Salmonella enterica-specific target sequences were identified by a comparative genomic approach. Several species-specific target sequences were evaluated for speci...

  1. Complete genome sequencing of a multidrug-resistant and human-invasive Salmonella enterica serovar Typhimurium strain of the emerging sequence type 213 genotype

    DOE PAGESBeta

    Calva, Edmundo; Silva, Claudia; Zaidi, Mussaret B.; Sanchez-Flores, Alejandro; Estrada, Karel; Silva, Genivaldo G. Z.; Soto-Jiménez, Luz M.; Wiesner, Magdalena; Fernández-Mora, Marcos; Edwards, Robert A.; et al

    2015-06-18

    Salmonella enterica subsp. enterica serovar Typhimurium strain YU39 was isolated in 2005 in the state of Yucatán, Mexico, from a human systemic infection. The YU39 strain is representative of the multidrug-resistant emergent sequence type 213 (ST213) genotype. The YU39 complete genome is composed of a chromosome and seven plasmids.

  2. Complete Genome Sequencing of a Multidrug-Resistant and Human-Invasive Salmonella enterica Serovar Typhimurium Strain of the Emerging Sequence Type 213 Genotype

    PubMed Central

    Calva, Edmundo; Zaidi, Mussaret B.; Sanchez-Flores, Alejandro; Estrada, Karel; Silva, Genivaldo G. Z.; Soto-Jiménez, Luz M.; Wiesner, Magdalena; Fernández-Mora, Marcos; Edwards, Robert A.

    2015-01-01

    Salmonella enterica subsp. enterica serovar Typhimurium strain YU39 was isolated in 2005 in the state of Yucatán, Mexico, from a human systemic infection. The YU39 strain is representative of the multidrug-resistant emergent sequence type 213 (ST213) genotype. The YU39 complete genome is composed of a chromosome and seven plasmids. PMID:26089426

  3. Complete Genome Sequence of Salmonella enterica Serovar Typhimurium Strain YU15 (Sequence Type 19) Harboring the Salmonella Genomic Island 1 and Virulence Plasmid pSTV

    PubMed Central

    Calva, Edmundo; Puente, José L.; Zaidi, Mussaret B.

    2016-01-01

    The complete genome of Salmonella enterica subsp. enterica serovar Typhimurium sequence type 19 (ST19) strain YU15, isolated in Yucatán, Mexico, from a human baby stool culture, was determined using PacBio technology. The chromosome contains five intact prophages and the Salmonella genomic island 1 (SGI1). This strain carries the Salmonella virulence plasmid pSTV. PMID:27081132

  4. Rapid multiplex PCR and Real-Time TaqMan PCR assays for detection of Salmonella enterica and the highly virulent serovars Choleraesuis and Paratyphi C

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is a human pathogen with over 2,500 serovars characterized. S. enterica serovars Choleraesuis (Cs) and Paratyphi C (Pc) are two globally distributed serovars. We have developed a rapid molecular typing method to detect Cs and Pc in food samples by using a comparative genomics ap...

  5. Antimicrobial resistance-conferring plasmids with similarity to virulence plasmids from avian pathogenic Escherichia coli strains in Salmonella enterica serovar Kentucky isolates from poultry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica, a leading cause of food-borne gastroenteritis worldwide, may be found in any raw food of animal, vegetable, or fruit origin. Salmonella serovars differ in distribution, virulence, and host specificity. Salmonella enterica serovar Kentucky, though often found in the food supply, ...

  6. Preslaughter Holding Environment in Pork Plants Is Highly Contaminated with Salmonella enterica

    PubMed Central

    Rostagno, M. H.; Hurd, H. S.; McKean, J. D.; Ziemer, C. J.; Gailey, J. K.; Leite, R. C.

    2003-01-01

    The objective of this study was to determine whether abattoir pens can provide a Salmonella enterica infection source during the 2 to 4 h of preharvest holding. Previous work has suggested that pigs may be getting infected, but little has been reported on the environmental contamination of abattoir holding pens. For 24 groups of pigs studied (∼150 animals/group) at two high-capacity abattoirs, six pooled fecal samples (n, 10 per pool) were collected from each transport trailer immediately after pigs were unloaded. Holding pens were sampled (one drinking water sample and six pooled floor samples consisting of swabs, residual liquid, and feces) prior to entry of study pigs for the routine holding period (∼2.5 h). After slaughter, cecal contents and ileocecal lymph nodes were collected, on the processing line, from 30 pigs in each studied group. All samples were cultured for the isolation and identification of S. enterica by primary enrichment in GN-Hajna and tetrathionate broths, secondary enrichment in Rappaport-Vassiliadis broth, and plating on brilliant green sulfa and xylose-lysine-tergitol-4 agars, followed by biochemical and serological identification. The study pens were highly contaminated with S. enterica; all holding pens sampled had at least one positive sample. Additionally, 33% (8 of 24) of drinking water samples were positive for S. enterica. All 24 groups of pigs had S. enterica-positive cecal contents and ileocecal lymph nodes, including those groups from transport trailers with no positive samples. From pigs, trailers, and pens, 586 isolates representing 36 different Salmonella serovars were isolated. Of the 353 isolates from pigs (109 from ileocecal lymph nodes plus 244 from cecal contents), 19% were identified as belonging to the same serovars as those isolated from the respective pens; 27% were identified as belonging to the same serovars as those isolated from the trailers. Sixteen percent of the unique serovars were isolated from both pigs

  7. Outbreak of unusual Salmonella enterica serovar Typhimurium monophasic variant 1,4 [5],12:i:-, Italy, June 2013 to September 2014.

    PubMed

    Cito, Francesca; Baldinelli, Francesca; Calistri, Paolo; Di Giannatale, Elisabetta; Scavia, Gaia; Orsini, Massimiliano; Iannetti, Simona; Sacchini, Lorena; Mangone, Iolanda; Candeloro, Luca; Conte, Annamaria; Ippoliti, Carla; Morelli, Daniela; Migliorati, Giacomo; Barile, Nadia Beatrice; Marfoglia, Cristina; Salucci, Stefania; Cammà, Cesare; Marcacci, Maurilia; Ancora, Massimo; Dionisi, Anna Maria; Owczartek, Slawomir; Luzzi, Ida

    2016-04-14

    Monophasic variant of Salmonella enterica subspecies enterica serovar Typhimurium (monophasic S. Typhimurium), with antigenic structure 1,4,[5],12:i:-, appears to be of increasing importance in Europe. In Italy, monophasic S. Typhimurium represented the third most frequent Salmonella serovar isolated from human cases between 2004 and 2008. From June 2013 to October 2014, a total of 206 human cases of salmonellosis were identified in Abruzzo region (Central Italy). Obtained clinical isolates characterised showed S. Typhimurium 1,4,[5],12:i:- with sole resistance to nalidixic acid, which had never been observed in Italy in monophasic S. Typhimurium, neither in humans nor in animals or foods. Epidemiological, microbiological and environmental investigations were conducted to try to identify the outbreak source. Cases were interviewed using a standardised questionnaire and microbiological tests were performed on human as well as environmental samples, including samples from fruit and vegetables, pigs, and surface water. Investigation results did not identify the final vehicle of human infection, although a link between the human cases and the contamination of irrigation water channels was suggested. PMID:27105170

  8. Effectiveness of a spontaneous carvacrol nanoemulsion against Salmonella enterica Enteritidis and Escherichia coli O157:H7 on contaminated broccoli and radish seeds.

    PubMed

    Landry, Kyle S; Micheli, Sean; McClements, David Julian; McLandsborough, Lynne

    2015-10-01

    The incidence of foodborne illness associated with the consumption of fresh produce has continued to increase over the past decade. Sprouts, such as mung bean, alfalfa, radish, and broccoli, are minimally processed and have been sources for foodborne illness. Currently, a 20,000 ppm calcium hypochlorite soak is recommended for the treatment of sprouting seeds. In this study, the efficacy of an antimicrobial carvacrol nanoemulsion was tested against Salmonella enterica subspecies enterica serovar Enteritidis (ATCC BAA-1045) or EGFP expressing Escherichia coli O157:H7 (ATCC 42895) contaminated sprouting seeds. Antimicrobial treatments were performed by soaking inoculated seeds in nanoemulsions (4000 or 8000 ppm) for 30 or 60 min. Following treatment, surviving cells were determined by performing plate counts and/or Most Probable Number (MPN) enumeration. Treated seeds were sprouted and tested for the presence of pathogens. Treatment successfully inactivated low levels (2 and 3 log CFU/g) of S. Enteritidis and E. coli on radish seeds when soaked for 60 min at concentrations ≥4000 (0.4%) ppm carvacrol. This treatment method was not affective on contaminated broccoli seeds. Total sprout yield was not influenced by any treatments. These results show that carvacrol nanoemulsions may be an alternative treatment method for contaminated radish seeds. PMID:26187822

  9. Detection of Salmonella enterica in pigs at slaughter and comparison with human isolates in Italy.

    PubMed

    Bonardi, Silvia; Alpigiani, Irene; Bruini, Ilaria; Barilli, Elena; Brindani, Franco; Morganti, Marina; Cavallini, Pierugo; Bolzoni, Luca; Pongolini, Stefano

    2016-02-01

    In 2013-2014, 201 pigs belonging to 67 batches were tested for Salmonella in their mesenteric lymph nodes (MLN) in one abattoir of Northern Italy. For each batch, faecal material was collected at lairage by swabbing the pen floor for approximately 1600 cm(2). The aim of this study was to investigate the prevalence of Salmonella in MLN of pigs at slaughter, to assess Salmonella contamination at lairage and to evaluate the effect of lairage duration on its prevalence. Serotyping, XbaI PFGE typing and antimicrobial testing of the isolates were performed. Pig and human Salmonella isolates of the same region of Italy were compared to evaluate possible correlations. Salmonella enterica was isolated from 19.9% of the MLN and 49.3% of the environmental faecal samples. Nine different serovars were identified among 75 S. enterica isolates. In MLN Salmonella Derby was the most common (52.5%), followed by S. enterica 4,[5],12:i:- (17.5%) and Salmonella Rissen (10.0%). In faecal samples S. Derby was prevalent (51.4%), followed by S. enterica 4,[5], 12:i:- (20.0%) and Salmonella Brandenburg (14.3%). Lairage holding varied between 1 and ≥ 12 h (median value: 2.5h). In pigs held for 1-3h, 14.1% were positive for Salmonella in MLN but the prevalence reached 31.8% when they were held for ≥ 12 h. The contamination of MLN was statistically different (p=0.0045) between the two groups, thus confirming the role of long-lasting lairage in Salmonella contamination of pigs. XbaI PFGE typing detected 36 PFGE types. Twenty-three PFGE types were identified among the 40 MLN isolates and 22 PFGE types among the 35 faecal isolates. A total of 11 PFGE types were shared between the MLN of pigs and the lairage environment. Among S. Derby, 6 shared PFGE types between MLN and faeces were found and among S. enterica 4,[5],12:i:- one PFGE type was common between MLN and the faecal samples. Shared profiles between human and swine isolates of S. Derby, S. enterica 4,[5],12:i:-, S. Rissen, Salmonella

  10. Identification of Salmonella enterica serovar Dublin-specific sequences by subtractive hybridization and analysis of their role in intestinal colonization and systemic translocation in cattle.

    PubMed

    Pullinger, Gillian D; Dziva, Francis; Charleston, Bryan; Wallis, Timothy S; Stevens, Mark P

    2008-11-01

    Salmonella enterica serovar Dublin is a host-restricted serovar associated with typhoidal disease in cattle. In contrast, the fowl-associated serovar S. enterica serovar Gallinarum is avirulent in calves, yet it invades ileal mucosa and induces enteritis at levels comparable to those induced by S. enterica serovar Dublin. Suppression subtractive hybridization was employed to identify S. enterica serovar Dublin strain SD3246 genes absent from S. enterica serovar Gallinarum strain SG9. Forty-one S. enterica serovar Dublin fragments were cloned and sequenced. Among these, 24 mobile-element-associated genes were identified, and 12 clones exhibited similarity with sequences of known or predicted function in other serovars. Three S. enterica serovar Dublin-specific regions were homologous to regions from the genome of Enterobacter sp. strain 638. Sequencing of fragments adjacent to these three sequences revealed the presence of a 21-kb genomic island, designated S. enterica serovar Dublin island 1 (SDI-1). PCR analysis and Southern blotting showed that SDI-1 is highly conserved within S. enterica serovar Dublin isolates but rarely found in other serovars. To probe the role of genes identified by subtractive hybridization in vivo, 24 signature-tagged S. enterica serovar Dublin SD3246 mutants lacking loci not present in Salmonella serovar Gallinarum SG9 were created and screened by oral challenge of cattle. Though attenuation of tagged SG9 and SD3246 Salmonella pathogenicity island-1 (SPI-1) and SPI-2 mutant strains was detected, no obvious defects of these 24 mutants were detected. Subsequently, a DeltaSDI-1 mutant was found to exhibit weak but significant attenuation compared with the parent strain in coinfection of calves. SDI-1 mutation did not impair invasion, intramacrophage survival, or virulence in mice, implying that SDI-1 does not influence fitness per se and may act in a host-specific manner. PMID:18794283

  11. Reduction of Salmonella enterica on the surface of eggshells by sequential treatment with aqueous chlorine dioxide and drying.

    PubMed

    Choi, Seonyeong; Park, Sunhyung; Kim, Yoonsook; Kim, Byeong-sam; Beuchat, Larry R; Hoikyung, Kim; Ryu, Jee-Hoon

    2015-10-01

    The synergistic effects of sequential treatments with chlorine dioxide (ClO2) and drying in killing Salmonella enterica on the surface of chicken eggshells were investigated. Initial experiments were focused on comparing lethalities of sodium hypochlorite (NaOCl) and ClO2. Eggs surface-inoculated with S. enterica in chicken feces as a carrier were immersed in water, NaOCl (50 or 200 μg/mL), or ClO2 (50 or 200 μg/mL) for 1 or 5 min. For 1-min treatments, lethal activities of sanitizers were not significantly different (P>0.05). However, after treatment with ClO2 for 5 min, reductions of S. enterica were significantly greater (P≤0.05) than reductions after treatment with water or NaOCl. The effect of treatment of eggs with ClO2 or NaOCl, followed by drying at 43% relative humidity and 25 °C for 24 and 48 h, were determined. Populations of S. enterica decreased during drying, regardless of the type of sanitizer treatment. ClO2 treatment, compared to water or NaOCl treatments, resulted in additional reductions of ca. >1.3 log CFU/egg during drying. This indicates that sequential treatments with ClO2 and drying induced synergistic lethal effects against S. enterica on the surface of eggshells. These observations will be useful when selecting a sanitizer to control S. enterica on the surface of eggshells and designing an effective egg sanitization system exploiting the synergistic lethal effects of sanitizer and drying. PMID:26114591

  12. Prevalence of Salmonella Isolates from Chicken and Pig Slaughterhouses and Emergence of Ciprofloxacin and Cefotaxime Co-Resistant S. enterica Serovar Indiana in Henan, China

    PubMed Central

    Bai, Li; Lan, Ruiting; Zhang, Xiuli; Cui, Shenghui; Xu, Jin; Guo, Yunchang; Li, Fengqin; Zhang, Ding

    2015-01-01

    The prevalence of Salmonella from chicken and pig slaughterhouses in Henan, China and antimicrobial susceptibility of these isolates to antibiotics was determined. From 283 chicken samples and 240 pig samples collected, 128 and 70 Salmonella isolates were recovered with an isolation rate of 45.2 and 29.2% respectively. The predominant serovars in chicken samples were S. enterica serovar Enteritidis, S. enterica serovar Hadar and S. enterica serovar Indiana, while those in pig samples were S. enterica serovar Typhimurium, S. enterica serovar Derby and S. enterica serovar Enteritidis. Resistance to ciprofloxacin was 8.6 and 10.0% for isolates from chickens and pigs respectively, whereas resistance to cefotaxime was 5.5 and 8.6%, respectively. Multidrug resistance (resistance to three or more classes of antimicrobial agent) was markedly higher in pig isolates (57.1%) than in chicken isolates (39.8%). Of particular concern was the detection of ciprofloxacin and cefotaxime co-resistant S. enterica serovar Indiana isolates, which pose risk to public health. All 16 S. enterica serovar Indiana isolates detected were resistant to ciprofloxacin, among which 11 were co-resistant to cefotaxime. The S. enterica serovar Indiana isolates accumulated point mutations in quinolone resistance determination regions of gyrA (S83F/D87G or S83F/D87N) and parC (T57S/S80R). Two plasmid mediated quinolone resistant determinants were found with aac (6')-Ib-cr and oqxAB in 16 and 12 S. enterica serovar Indiana isolates respectively. Cefotaxime-resistance of S. enterica serovar Indiana was associated with the acquisition of a blaCTX-M-65 gene. The potential risk of ciprofloxacin and cefotaxime co-resistant S. enterica serovar Indiana infection is a significant concern due to limited alternative treatment options. Reduction of Salmonella in chicken and pig slaughterhouses, in particular, ciprofloxacin and cefotaxime co-resistant S. enterica serovar Indiana will be an important measure to reduce

  13. Evaluation of Surrogate Disk Tests for Detection of Ciprofloxacin and Levofloxacin Resistance in Clinical Isolates of Salmonella enterica

    PubMed Central

    Deak, Eszter; Skov, Robert; Hindler, Janet A.

    2015-01-01

    Detection of fluoroquinolone resistance in Salmonella enterica has become increasingly difficult due to evolving resistance mechanisms to this antimicrobial class in this organism. We evaluated two quinolone disks and five fluoroquinolone disks for their ability to act as a surrogate agent for the detection of fluoroquinolone resistance in a collection of 136 S. enterica isolates, including 111 with intermediate or resistant ciprofloxacin MICs mediated by a variety of resistance mechanisms. Ciprofloxacin, ofloxacin, and pefloxacin disks detected all isolates resistant to ciprofloxacin (0% very major error) and yielded false resistance (major error) in 8, 4, and 12% of susceptible isolates, respectively. Ciprofloxacin and pefloxacin provided clearer differentiation of susceptible and resistant isolates. PMID:26292293

  14. Association of virulence plasmid and antibiotic resistance determinants with chromosomal multilocus genotypes in Mexican Salmonella enterica serovar Typhimurium strains

    PubMed Central

    2009-01-01

    Background Bacterial genomes are mosaic structures composed of genes present in every strain of the same species (core genome), and genes present in some but not all strains of a species (accessory genome). The aim of this study was to compare the genetic diversity of core and accessory genes of a Salmonella enterica subspecies enterica serovar Typhimurium (Typhimurium) population isolated from food-animal and human sources in four regions of Mexico. Multilocus sequence typing (MLST) and macrorestriction fingerprints by pulsed-field gel electrophoresis (PFGE) were used to address the core genetic variation, and genes involved in pathogenesis and antibiotic resistance were selected to evaluate the accessory genome. Results We found a low genetic diversity for both housekeeping and accessory genes. Sequence type 19 (ST19) was supported as the founder genotype of STs 213, 302 and 429. We found a temporal pattern in which the derived ST213 is replacing the founder ST19 in the four geographic regions analyzed and a geographic trend in the number of resistance determinants. The distribution of the accessory genes was not random among chromosomal genotypes. We detected strong associations among the different accessory genes and the multilocus chromosomal genotypes (STs). First, the Salmonella virulence plasmid (pSTV) was found mostly in ST19 isolates. Second, the plasmid-borne betalactamase cmy-2 was found only in ST213 isolates. Third, the most abundant integron, IP-1 (dfrA12, orfF and aadA2), was found only in ST213 isolates. Fourth, the Salmonella genomic island (SGI1) was found mainly in a subgroup of ST19 isolates carrying pSTV. The mapping of accessory genes and multilocus genotypes on the dendrogram derived from macrorestiction fingerprints allowed the establishment of genetic subgroups within the population. Conclusion Despite the low levels of genetic diversity of core and accessory genes, the non-random distribution of the accessory genes across chromosomal

  15. Characterization of pathogenic and resistant genome repertoire reveals two clonal lines in Salmonella enterica subsp. enterica serovar Paratyphi B (+)-tartrate positive.

    PubMed

    Huehn, Stephan; Helmuth, Reiner; Bunge, Cornelia; Guerra, Beatriz; Junker, Ernst; Davies, Rob H; Wattiau, Pierre; van Pelt, Wilfrid; Malorny, Burkhard

    2009-05-01

    A total of 36 contemporary human, animal, and environmental (+)-tartrate-fermenting (dT+) Salmonella enterica serovar Paratyphi B isolates, formerly called Salmonella serovar Java, and five related monophasic S. enterica serovar 4,5,12:b:- isolates from Belgium, Germany, the Netherlands, and the United Kingdom were investigated for clonality and antimicrobial resistance profiles, as well as their virulence and resistance gene repertoire. Two major clonal lines, which could be phenotypically differentiated by the expression of the O:5 antigen, were identified. All O:5 antigen negative strains were multidrug resistant and originated (with two exceptions) from Belgian, Dutch, or German poultry. Strains exhibiting the O:5 antigen encoded by the oafA gene revealed a more heterogeneous group including multidrug-resistant and susceptible strains. Compared to O:5 antigen negative isolates, Salmonella Paratyphi B dT+ O:5 positive strains possessed additional virulence determinants. The Salmonella genomic island 1 was only found in O:5 positive strains. Five monophasic Salmonella 4,5,12:b:- lacking the phase-2 flagellar antigen were assigned to Salmonella Paratyphi B dT+ isolates of the O:5 positive group. The conclusion of the analysis is that Salmonella Paratyphi B dT+ O:5 negative and O:5 positive isolates evolved from a different lineage. Salmonella Paratyphi B dT+ O:5 positive strains possess additional fimbrial and virulence genes that probably enable this clone to interact with a broader range of hosts and the environment. Salmonella Paratyphi B dT+ O:5 negative continuously persists in poultry across Western Europe, especially Belgium, the Netherlands, and Germany. PMID:19292689

  16. TaqMan Salmonella enterica Detection Kit. Performance Tested Method 020803.

    PubMed

    Tebbs, Robert S; Cao, Yan Y; Balachandran, Priva; Petrauskene, Olga

    2009-01-01

    Peanut butter spiked with Salmonella enterica ser. Typhimurium was prepared by an independent laboratory and sent to Applied Biosystems to determine the sensitivity and specificity of the TaqMan Salmonella enterica Detection Kit for detecting Salmonella in peanut butter. The samples were spiked at three levels: five no-spike (0 CFU/25 g); 20 low-spike (0.2 CFU/25 g); and 20 high-spike (2 CFU/25 g). They were coded to create a blind set of 45 samples. The samples were processed based on an unpaired test design that included enrichment in buffered peptone water for the candidate method and lactose broth for the reference method. In the candidate method, a 1 mL aliquot of enriched sample was extracted using PrepMan Ultra Sample Preparation Reagent; the sample was amplified on the Applied Biosystems 7500 real-time PCR system, and analyzed for detection of Salmonella using RapidFinder Version 1.0 software. All samples processed by the candidate method were confirmed by culture according to the U.S. Food and Drug Administration's Bacteriological Analytical Manual procedures. Sensitivity, specificity, and Chi-square analysis were calculated by combining candidate method results with those of the reference method that were collected by the independent laboratory. The TaqMan Salmonella enterica Detection Kit showed 40% sensitivity, 100% specificity, and a Chi-square value equal to 1.52. Chi-square analysis indicated the candidate method and the reference method were comparable. Although the candidate method sensitivity was only 40% when compared with the reference method (unpaired samples), the sensitivity was > 100% when the candidate method results were compared with those of the confirmation method (same sample enrichment). PMID:20166614

  17. Molecular Properties of Salmonella enterica Serotype Paratyphi B Distinguish between Its Systemic and Its Enteric Pathovars

    PubMed Central

    Prager, Rita; Rabsch, Wolfgang; Streckel, Wiebke; Voigt, Wolfgang; Tietze, Erhardt; Tschäpe, Helmut

    2003-01-01

    Salmonella enterica serotype O1,4,5,12:Hb:1,2, designated according to the current Kauffmann-White scheme as S. enterica serotype Paratyphi B, is a very diverse serotype with respect to its clinical and microbiological properties. PCR and blot techniques, which identify the presence, polymorphism, and expression of various effector protein genes, help to distinguish between strains with systemic and enteric outcomes of disease. All serotype Paratyphi B strains from systemic infections have been found to be somewhat genetically related with respect to the pattern of their virulence genes sopB, sopD, sopE1, avrA, and sptP as well as other molecular properties (multilocus enzyme electrophoresis type, pulsed-field gel electrophoresis [PFGE] type, ribotype, and IS200 type). They have been classified as members of the systemic pathovar (SPV). All these SPV strains possess a new sopE1-carrying bacteriophage (designated ΦSopE309) with high SopE1 protein expression but lack the commonly occurring avrA determinant. They exhibit normal SopB protein expression but lack SopD protein production. In contrast, strains from enteric infections classified as belonging to the enteric pathovar possess various combinations of the respective virulence genes, PFGE pattern, and ribotypes. We propose that the PCR technique for testing for the presence of the virulence genes sopE1 and avrA be used as a diagnostic tool for identifying both pathovars of S. enterica serotype Paratyphi B. This will be of great public health importance, since strains of serotype Paratyphi B have recently reemerged worldwide. PMID:12958256

  18. Streptomycin Induced Stress Response in Salmonella enterica Serovar Typhimurium Shows Distinct Colony Scatter Signature

    PubMed Central

    Singh, Atul K.; Drolia, Rishi; Bai, Xingjian; Bhunia, Arun K.

    2015-01-01

    We investigated the streptomycin-induced stress response in Salmonella enterica serovars with a laser optical sensor, BARDOT (bacterial rapid detection using optical scattering technology). Initially, the top 20 S. enterica serovars were screened for their response to streptomycin at 100 μg/mL. All, but four S. enterica serovars were resistant to streptomycin. The MIC of streptomycin-sensitive serovars (Enteritidis, Muenchen, Mississippi, and Schwarzengrund) varied from 12.5 to 50 μg/mL, while streptomycin-resistant serovar (Typhimurium) from 125–250 μg/mL. Two streptomycin-sensitive serovars (Enteritidis and Mississippi) were grown on brain heart infusion (BHI) agar plates containing sub-inhibitory concentration of streptomycin (1.25–5 μg/mL) and a streptomycin-resistant serovar (Typhimurium) was grown on BHI containing 25–50 μg/mL of streptomycin and the colonies (1.2 ± 0.1 mm diameter) were scanned using BARDOT. Data show substantial qualitative and quantitative differences in the colony scatter patterns of Salmonella grown in the presence of streptomycin than the colonies grown in absence of antibiotic. Mass-spectrometry identified overexpression of chaperonin GroEL, which possibly contributed to the observed differences in the colony scatter patterns. Quantitative RT-PCR and immunoassay confirmed streptomycin-induced GroEL expression while, aminoglycoside adenylyltransferase (aadA), aminoglycoside efflux pump (aep), multidrug resistance subunit acrA, and ribosomal protein S12 (rpsL), involved in streptomycin resistance, were unaltered. The study highlights suitability of the BARDOT as a non-invasive, label-free tool for investigating stress response in Salmonella in conjunction with the molecular and immunoassay methods. PMID:26252374

  19. Molecular Characterization of Salmonella enterica Serovar Aberdeen Negative for H2S Production in China.

    PubMed

    Wu, Fuli; Xu, Xuebin; Xie, Jing; Yi, Shengjie; Wang, Jian; Yang, Xiaoxia; Yang, Chaojie; Liang, Beibei; Ma, Qiuxia; Li, Hao; Song, Hongbin; Qiu, Shaofu

    2016-01-01

    Salmonella enterica infections continue to be a significant burden on public health worldwide. The ability of S. enterica to produce hydrogen sulfide (H2S) is an important phenotypic characteristic used to screen and identify Salmonella with selective medium; however, H2S-negative Salmonella have recently emerged. In this study, the H2S phenotype of Salmonella isolates was confirmed, and the selected isolates were subjected to antimicrobial susceptibility testing and molecular identification by multilocus sequence typing, pulsed-field gel electrophoresis, and clustered regularly interspaced short palindromic repeat (CRISPR) analysis. The phs genetic operon was also analyzed. A total of 160 S. enterica serovar Aberdeen isolates were detected between 2005 and 2013 in China. Of them, seven non-H2S-producing isolates were detected. Notably, four samples yielded four pairs of isolates with different H2S phenotypes, simultaneously. The data demonstrated that H2S-negative isolates were genetically closely related to H2S-positive isolates. Three new spacers (Abe1, Abe2, and Abe3) were identified in CRISPR locus 1 in four pairs of isolates with different H2S phenotypes from the same samples. Sequence analysis revealed a new nonsense mutation at position 208 in the phsA gene of all non-H2S-producing isolates. Additionally, we describe a new screening procedure to avoid H2S-negative Salmonella, which would normally be overlooked during laboratory and hospital screening. The prevalence of this pathogen may be underestimated; therefore, it is important to focus on improving surveillance of this organism to control its spread. PMID:27552230

  20. Molecular Characterization of Salmonella enterica Serovar Aberdeen Negative for H2S Production in China

    PubMed Central

    Yi, Shengjie; Wang, Jian; Yang, Xiaoxia; Yang, Chaojie; Liang, Beibei; Ma, Qiuxia; Li, Hao; Song, Hongbin; Qiu, Shaofu

    2016-01-01

    Salmonella enterica infections continue to be a significant burden on public health worldwide. The ability of S. enterica to produce hydrogen sulfide (H2S) is an important phenotypic characteristic used to screen and identify Salmonella with selective medium; however, H2S-negative Salmonella have recently emerged. In this study, the H2S phenotype of Salmonella isolates was confirmed, and the selected isolates were subjected to antimicrobial susceptibility testing and molecular identification by multilocus sequence typing, pulsed-field gel electrophoresis, and clustered regularly interspaced short palindromic repeat (CRISPR) analysis. The phs genetic operon was also analyzed. A total of 160 S. enterica serovar Aberdeen isolates were detected between 2005 and 2013 in China. Of them, seven non-H2S-producing isolates were detected. Notably, four samples yielded four pairs of isolates with different H2S phenotypes, simultaneously. The data demonstrated that H2S-negative isolates were genetically closely related to H2S-positive isolates. Three new spacers (Abe1, Abe2, and Abe3) were identified in CRISPR locus 1 in four pairs of isolates with different H2S phenotypes from the same samples. Sequence analysis revealed a new nonsense mutation at position 208 in the phsA gene of all non-H2S-producing isolates. Additionally, we describe a new screening procedure to avoid H2S-negative Salmonella, which would normally be overlooked during laboratory and hospital screening. The prevalence of this pathogen may be underestimated; therefore, it is important to focus on improving surveillance of this organism to control its spread. PMID:27552230

  1. Effect of desiccation on tolerance of salmonella enterica to multiple stresses.

    PubMed

    Gruzdev, Nadia; Pinto, Riky; Sela, Shlomo

    2011-03-01

    Reducing the available water in food is a long-established method for controlling bacterial growth in the food industry. Nevertheless, food-borne outbreaks of salmonellosis due to consumption of dry foods have been continuously reported. Previous studies showed that dried Salmonella cells acquire high tolerance to heat and ethanol. In order to examine if dehydration also induces tolerance to other stressors, dried Salmonella enterica serotype Typhimurium cells were exposed to multiple stresses, and their viability was assessed. Indeed, desiccated S. Typhimurium acquired higher tolerance to multiple stressors than nondesiccated cells. The dried cells were significantly more resistant to most stressors, including ethanol (10 to 30%, 5 min), sodium hypochlorite (10 to 100 ppm, 10 min), didecyl dimethyl ammonium chloride (0.05 to 0.25%, 5 min), hydrogen peroxide (0.5 to 2.0%, 30 min), NaCl (0.1 to 1 M, 2 h), bile salts (1 to 10%, 2 h), dry heat (100°C, 1 h), and UV irradiation (125 μW/cm(2), 25 min). In contrast, exposure of Salmonella to acetic and citric acids reduced the survival of the dried cells (1.5 log) compared to that of nondesiccated cells (0.5 log). Three other S. enterica serotypes, S. Enteritidis, S. Newport, and S. Infantis, had similar stress responses as S. Typhimurium, while S. Hadar was much more susceptible and gained tolerance to only a few stressors. Our findings indicate that dehydration induces cross-tolerance to multiple stresses in S. enterica, demonstrating the limitations of current chemical and physical treatments utilized by the food industry to inactivate food-borne pathogens. PMID:21216905

  2. Streptomycin Induced Stress Response in Salmonella enterica Serovar Typhimurium Shows Distinct Colony Scatter Signature.

    PubMed

    Singh, Atul K; Drolia, Rishi; Bai, Xingjian; Bhunia, Arun K

    2015-01-01

    We investigated the streptomycin-induced stress response in Salmonella enterica serovars with a laser optical sensor, BARDOT (bacterial rapid detection using optical scattering technology). Initially, the top 20 S. enterica serovars were screened for their response to streptomycin at 100 μg/mL. All, but four S. enterica serovars were resistant to streptomycin. The MIC of streptomycin-sensitive serovars (Enteritidis, Muenchen, Mississippi, and Schwarzengrund) varied from 12.5 to 50 μg/mL, while streptomycin-resistant serovar (Typhimurium) from 125-250 μg/mL. Two streptomycin-sensitive serovars (Enteritidis and Mississippi) were grown on brain heart infusion (BHI) agar plates containing sub-inhibitory concentration of streptomycin (1.25-5 μg/mL) and a streptomycin-resistant serovar (Typhimurium) was grown on BHI containing 25-50 μg/mL of streptomycin and the colonies (1.2 ± 0.1 mm diameter) were scanned using BARDOT. Data show substantial qualitative and quantitative differences in the colony scatter patterns of Salmonella grown in the presence of streptomycin than the colonies grown in absence of antibiotic. Mass-spectrometry identified overexpression of chaperonin GroEL, which possibly contributed to the observed differences in the colony scatter patterns. Quantitative RT-PCR and immunoassay confirmed streptomycin-induced GroEL expression while, aminoglycoside adenylyltransferase (aadA), aminoglycoside efflux pump (aep), multidrug resistance subunit acrA, and ribosomal protein S12 (rpsL), involved in streptomycin resistance, were unaltered. The study highlights suitability of the BARDOT as a non-invasive, label-free tool for investigating stress response in Salmonella in conjunction with the molecular and immunoassay methods. PMID:26252374

  3. Inhibition of Salmonella enterica Biofilm Formation Using Small-Molecule Adenosine Mimetics

    PubMed Central

    Koopman, Jacob A.; Marshall, Joanna M.; Bhatiya, Aditi; Eguale, Tadesse; Kwiek, Jesse J.

    2014-01-01

    Biofilms have been widely implicated in chronic infections and environmental persistence of Salmonella enterica, facilitating enhanced colonization of surfaces and increasing the ability of the bacteria to be transmitted to new hosts. Salmonella enterica serovar Typhi biofilm formation on gallstones from humans and mice enhances gallbladder colonization and bacterial shedding, while Salmonella enterica serovar Typhimurium biofilms facilitate long-term persistence in a number of environments important to food, medical, and farming industries. Salmonella regulates expression of many virulence- and biofilm-related processes using kinase-driven pathways. Kinases play pivotal roles in phosphorylation and energy transfer in cellular processes and possess an ATP-binding pocket required for their functions. Many other cellular proteins also require ATP for their activity. Here we test the hypothesis that pharmacological interference with ATP-requiring enzymes utilizing adenosine mimetic compounds would decrease or inhibit bacterial biofilm formation. Through the screening of a 3,000-member ATP mimetic library, we identified a single compound (compound 7955004) capable of significantly reducing biofilm formation by S. Typhimurium and S. Typhi. The compound was not bactericidal or bacteriostatic toward S. Typhimurium or cytotoxic to mammalian cells. An ATP-Sepharose affinity matrix technique was used to discover potential protein-binding targets of the compound and identified GroEL and DeoD. Compound 7955004 was screened against other known biofilm-forming bacterial species and was found to potently inhibit biofilms of Acinetobacter baumannii as well. The identification of a lead compound with biofilm-inhibiting capabilities toward Salmonella provides a potential new avenue of therapeutic intervention against Salmonella biofilm formation, with applicability to biofilms of other bacterial pathogens. PMID:25313216

  4. Prevalence, Distribution, and Diversity of Salmonella enterica in a Major Produce Region of California▿†

    PubMed Central

    Gorski, Lisa; Parker, Craig T.; Liang, Anita; Cooley, Michael B.; Jay-Russell, Michele T.; Gordus, Andrew G.; Atwill, E. Robert; Mandrell, Robert E.

    2011-01-01

    A survey was initiated to determine the prevalence of Salmonella enterica in the environment in and around Monterey County, CA, a major agriculture region of the United States. Trypticase soy broth enrichment cultures of samples of soil/sediment (n = 617), water (n = 252), wildlife (n = 476), cattle feces (n = 795), and preharvest lettuce and spinach (n = 261) tested originally for the presence of pathogenic Escherichia coli were kept in frozen storage and later used to test for the presence of S. enterica. A multipathogen oligonucleotide microarray was employed to identify a subset of samples that might contain Salmonella in order to test various culture methods to survey a larger number of samples. Fifty-five of 2,401 (2.3%) samples yielded Salmonella, representing samples obtained from 20 different locations in Monterey and San Benito Counties. Water had the highest percentage of positives (7.1%) among sample types. Wildlife yielded 20 positive samples, the highest number among sample types, with positive samples from birds (n = 105), coyotes (n = 40), deer (n = 104), elk (n = 39), wild pig (n = 41), and skunk (n = 13). Only 16 (2.6%) of the soil/sediment samples tested positive, and none of the produce samples had detectable Salmonella. Sixteen different serotypes were identified among the isolates, including S. enterica serotypes Give, Typhimurium, Montevideo, and Infantis. Fifty-four strains were sensitive to 12 tested antibiotics; one S. Montevideo strain was resistant to streptomycin and gentamicin. Pulsed-field gel electrophoresis (PFGE) analysis of the isolates revealed over 40 different pulsotypes. Several strains were isolated from water, wildlife, or soil over a period of several months, suggesting that they were persistent in this environment. PMID:21378057

  5. Small Molecule Restores Itaconate Sensitivity in Salmonella enterica: A Potential New Approach to Treating Bacterial Infections.

    PubMed

    Hammerer, Fabien; Chang, Justin H; Duncan, Dustin; Castañeda Ruiz, Angel; Auclair, Karine

    2016-08-17

    In the context of increasing global antibiotic resistance, the need for alternative therapeutic targets is great. Although new antibiotics and resistance inhibitors provide temporary solutions, they are bound to become obsolete. In this work, we propose a new approach, coined "bacterio-modulation" that aims to restore macrophage potency towards bacterial strains that are able to survive in phagolysosomes. One key defense in the macrophage's arsenal is itaconate, an endogenous molecule with antimicrobial activity. Some intracellular pathogens have evolved to produce itaconate-degrading enzymes, which are required for intracellular proliferation and to promote pathogenicity. We herein present the first molecule able to resensitize Salmonella enterica to itaconate. PMID:27254798

  6. Antibody Is Required for Protection against Virulent but Not Attenuated Salmonella enterica Serovar Typhimurium

    PubMed Central

    McSorley, Stephen J.; Jenkins, Marc K.

    2000-01-01

    Resolution of infection with attenuated Salmonella is an active process that requires CD4+ T cells. Here, we demonstrate that costimulation via the surface molecule CD28, but not antibody production by B cells, is required for clearance of attenuated aroA Salmonella enterica serovar typhimurium. In contrast, specific antibody is critical for vaccine-induced protection against virulent bacteria. Therefore, CD28+ CD4+ T cells are sufficient for clearance of avirulent Salmonella in naive hosts, whereas CD4+ T cells and specific antibodies are required for protection from virulent Salmonella in immune hosts. PMID:10816483

  7. Extended-Spectrum Cephalosporin-Resistant Salmonella enterica serovar Heidelberg Strains, the Netherlands(1).

    PubMed

    Liakopoulos, Apostolos; Geurts, Yvon; Dierikx, Cindy M; Brouwer, Michael S M; Kant, Arie; Wit, Ben; Heymans, Raymond; van Pelt, Wilfrid; Mevius, Dik J

    2016-07-01

    Extended-spectrum cephalosporin-resistant Salmonella enterica serovar Heidelberg strains (JF6X01.0022/XbaI.0251, JF6X01.0326/XbaI.1966, JF6X01.0258/XbaI.1968, and JF6X01.0045/XbaI.1970) have been identified in the United States with pulsed-field gel electrophoresis. Our examination of isolates showed introduction of these strains in the Netherlands and highlight the need for active surveillance and intervention strategies by public health organizations. PMID:27314180

  8. High-Efficiency, Two-Step Scarless-Markerless Genome Genetic Modification in Salmonella enterica.

    PubMed

    Geng, Shizhong; Tian, Qin; An, Shuming; Pan, Zhiming; Chen, Xiang; Jiao, Xinan

    2016-06-01

    We present a two-step method for scarless-markerless genome genetic modification in Salmonella enterica based on the improved suicide plasmid pGMB152. The whole LacZYA gene can provide a lacZ-based blue/white screening strategy for fast selection of double-crossover mutants by allelic exchange. The high efficiency of this genetic engineering strategy permits the study of gene function by gene knockin, site-directed mutagenesis, and gene knockout to construct live attenuated vaccines. PMID:26883127

  9. Extended-Spectrum Cephalosporin-Resistant Salmonella enterica serovar Heidelberg Strains, the Netherlands1

    PubMed Central

    Geurts, Yvon; Dierikx, Cindy M.; Brouwer, Michael S.M.; Kant, Arie; Wit, Ben; Heymans, Raymond; van Pelt, Wilfrid; Mevius, Dik J.

    2016-01-01

    Extended-spectrum cephalosporin-resistant Salmonella enterica serovar Heidelberg strains (JF6X01.0022/XbaI.0251, JF6X01.0326/XbaI.1966, JF6X01.0258/XbaI.1968, and JF6X01.0045/XbaI.1970) have been identified in the United States with pulsed-field gel electrophoresis. Our examination of isolates showed introduction of these strains in the Netherlands and highlight the need for active surveillance and intervention strategies by public health organizations. PMID:27314180

  10. Sensitive Detection and Serovar Differentiation of Typhoidal and Nontyphoidal Salmonella enterica Species Using 16S rRNA Gene PCR Coupled with High-Resolution Melt Analysis

    PubMed Central

    Masek, Billie J.; Hardick, Justin; Won, Helen; Yang, Samuel; Hsieh, Yu-Hsiang; Rothman, Richard E.; Gaydos, Charlotte A.

    2015-01-01

    Salmonella enterica species infections are a significant public health problem causing high morbidity rates worldwide and high mortality rates in the developing world. These infections are not always rapidly diagnosed as a cause of bloodstream infections because of the limitations of blood culture, which greatly affects clinical care as a result of treatment delays. A molecular diagnostic assay that could rapidly detect and identify S. enterica species infections as a cause of sepsis is needed. Nine typhoidal and nontyphoidal S. enterica serovars were used to establish the limit of detection (LOD) of a previously published 16S rRNA gene PCR (16S PCR) in mock whole blood specimens. In addition, 16 typhoidal and nontyphoidal S. enterica serovars were used to evaluate the serovar differentiation capability of 16S PCR coupled with high-resolution melt analysis. The overall LOD of 16S PCR for the nine typhoidal and nontyphoidal S. enterica serovars analyzed was <10 colony-forming units per milliliter (CFU/mL) in mock whole blood specimens, with the lowest and highest LOD at <1 CFU/mL and 9 CFU/mL, respectively. By high-resolution melt analysis, the typhoidal and nontyphoidal S. enterica serovar groups analyzed each generated a unique grouping code, allowing for serovar-level identification. 16S PCR coupled with high-resolution melt analysis could be a useful molecular diagnostic that could enhance the current diagnostic, treatment, and surveillance methods of S. enterica bloodstream infections. PMID:24365382

  11. Crop Isolated Lymphoid Follicles and Ileal Peyer’s patches in Egg-Layer Hens Challenged with Salmonella enterica Enteritidis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The enteric pathogen Salmonella enterica Enteritidis (SE) can be harbored within the upper and lower gastrointestinal (GI) tract of chickens. Induction of immune response by SE at various alimentary tract regions may perhaps be attributable to local gut-associated lymphoid tissue (GALT). The study...

  12. Survival of Salmonella enterica on soybean sprouts following treatments with gaseous chlorine dioxide and biocontrol Pseudomonas bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Control of Salmonella enterica on sprouts and minimally processed, ready-to-eat fruits and vegetables is important for food and consumer safety. The aim of this research was to assess the effects of gaseous chlorine dioxide(ClO2)and biocontrol microorganisms (Pseudomonas chlororaphis and P. fluoresc...

  13. Differences in the motility phenotype of multidrug-resistant Salmonella enterica serovar Typhimurium exposed to various antibiotics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the most prevalent foodborne-associated bacteria in humans and livestock, and over 35 per cent of these isolates are resistant to three or more antibiotics. This is a concern as multidrug-resistant (MDR) Salmonella has been associat...

  14. Evolutionary trends in two strains of Salmonella enterica subsp. I serovar Enteritidis PT13a that vary in virulence potential

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. I serovar Enteritidis (S. Enteritidis) is the world's leading cause of salmonellosis. Eggs contaminated by apparently healthy hens and that have been improperly cooked can result in illness in humans who consume them. Although the incidence of this pathogen within the Uni...

  15. Identification of SNPs in two Salmonella enterica serovar Enteritidis PT13a pathotypes that point to epidemiological trends.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract: Salmonella enterica subsp. I serovar Enteritidis (S. Enteritidis) is the most frequent cause of salmonellosis in the world. Epidemiological data from the Centers for Disease Control indicates that the incidence of illness from S. Enteritidis in the United States increased during 2005 despi...

  16. Intergenic Sequence Ribotyping using a region neighboring dkgB links genovar to Kauffman-White serotype of Salmonella enterica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous research identified that the 5S ribosomal (rrn) gene and associated flanking sequences that are closely linked to the dkgB gene of Salmonella enterica were highly variable between serotypes, but not between subpopulations within the same serotype (PMID: 17005008). The degree of variability ...

  17. Evolutionary trends in two strains of Salmonella enterica subsp. I serovar Enteritidis PT13a that vary in virulence potential.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. I serovar Enteritidis (S. Enteritidis) is the world's leading cause of salmonellosis. Eggs contaminated by apparently healthy hens and that have been improperly cooked can result in illness in humans who consume them. Although the incidence of this pathogen within the Unit...

  18. Refined Live Attenuated Salmonella enterica Serovar Typhimurium and Enteritidis Vaccines Mediate Homologous and Heterologous Serogroup Protection in Mice

    PubMed Central

    Schmidlein, Patrick; Simon, Raphael; Pasetti, Marcela F.; Galen, James E.; Levine, Myron M.

    2015-01-01

    Invasive nontyphoidal Salmonella (NTS) infections constitute a major health problem among infants and toddlers in sub-Saharan Africa; these infections also occur in infants and the elderly in developed countries. We genetically engineered a Salmonella enterica serovar Typhimurium strain of multilocus sequence type 313, the predominant genotype circulating in sub-Saharan Africa. We evaluated the capacities of S. Typhimurium and Salmonella enterica serovar Enteritidis ΔguaBA ΔclpX live oral vaccines to protect mice against a highly lethal challenge dose of the homologous serovar and determined protection against other group B and D serovars circulating in sub-Saharan Africa. The vaccines S. Typhimurium CVD 1931 and S. Enteritidis CVD 1944 were immunogenic and protected BALB/c mice against 10,000 50% lethal doses (LD50) of S. Typhimurium or S. Enteritidis, respectively. S. Typhimurium CVD 1931 protected mice against the group B serovar Salmonella enterica serovar Stanleyville (91% vaccine efficacy), and S. Enteritidis CVD 1944 protected mice against the group D serovar Salmonella enterica serovar Dublin (85% vaccine efficacy). High rates of survival were observed when mice were infected 12 weeks postimmunization, indicating that the vaccines elicited long-lived protective immunity. Whereas CVD 1931 did not protect against S. Enteritidis R11, CVD 1944 did mediate protection against S. Typhimurium D65 (81% efficacy). These findings suggest that a bivalent (S. Typhimurium and S. Enteritidis) vaccine would provide broad protection against the majority of invasive NTS infections in sub-Saharan Africa. PMID:26351285

  19. Identification of multidrug-resistant Salmonella enterica serovar typhimurium isolates that have an antibiotic-induced invasion phenotype

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multidrug-resistant (MDR) Salmonella is an important food safety issue in humans and animals. The National Antimicrobial Resistance Monitoring System (NARMS) has reported that 27.3% of Salmonella enterica serotype Typhimurium isolates in humans were resistant to three or more classes of antibiotics...

  20. Critical role of glycogen synthase kinase-3ß in regulating the avian heterophil response to Salmonella enterica serovar Enteritidis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A microarray-assisted gene expression screen of chicken heterophils revealed glycogen synthase kinase-3ß (GSK-3ß), a multifunctional Ser/Thr kinase, to be consistently up-regulated 30-180 min following stimulation with Salmonella enterica serovar Enteritidis (S. Enteritidis). The present study was ...

  1. Combining essential oils and olive extract for control of multi-drug resistant Salmonella enterica on organic leafy greens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated the combined antimicrobial effects of plant essential oils and olive extract against antibiotic resistant Salmonella enterica serovar Newport on organic leafy greens. Organic baby spinach, mature spinach, romaine lettuce, and iceberg lettuce were inoculated with S. Newport and dip-t...

  2. Refined live attenuated Salmonella enterica serovar Typhimurium and Enteritidis vaccines mediate homologous and heterologous serogroup protection in mice.

    PubMed

    Tennant, Sharon M; Schmidlein, Patrick; Simon, Raphael; Pasetti, Marcela F; Galen, James E; Levine, Myron M

    2015-12-01

    Invasive nontyphoidal Salmonella (NTS) infections constitute a major health problem among infants and toddlers in sub-Saharan Africa; these infections also occur in infants and the elderly in developed countries. We genetically engineered a Salmonella enterica serovar Typhimurium strain of multilocus sequence type 313, the predominant genotype circulating in sub-Saharan Africa. We evaluated the capacities of S. Typhimurium and Salmonella enterica serovar Enteritidis ΔguaBA ΔclpX live oral vaccines to protect mice against a highly lethal challenge dose of the homologous serovar and determined protection against other group B and D serovars circulating in sub-Saharan Africa. The vaccines S. Typhimurium CVD 1931 and S. Enteritidis CVD 1944 were immunogenic and protected BALB/c mice against 10,000 50% lethal doses (LD50) of S. Typhimurium or S. Enteritidis, respectively. S. Typhimurium CVD 1931 protected mice against the group B serovar Salmonella enterica serovar Stanleyville (91% vaccine efficacy), and S. Enteritidis CVD 1944 protected mice against the group D serovar Salmonella enterica serovar Dublin (85% vaccine efficacy). High rates of survival were observed when mice were infected 12 weeks postimmunization, indicating that the vaccines elicited long-lived protective immunity. Whereas CVD 1931 did not protect against S. Enteritidis R11, CVD 1944 did mediate protection against S. Typhimurium D65 (81% efficacy). These findings suggest that a bivalent (S. Typhimurium and S. Enteritidis) vaccine would provide broad protection against the majority of invasive NTS infections in sub-Saharan Africa. PMID:26351285

  3. First report of extended-spectrum-beta-lactamase-producing Salmonella enterica serovar Kentucky isolated from poultry in Ireland.

    PubMed

    Boyle, F; Morris, D; O'Connor, J; Delappe, N; Ward, J; Cormican, M

    2010-01-01

    Therapy of invasive human salmonellosis is complicated by increasing antimicrobial resistance. Food animals are the principal source of infection with nontyphoid Salmonella. We report the emergence of broad-spectrum-cephalosporin resistance in Salmonella enterica serovar Kentucky in poultry in Ireland. PMID:19884382

  4. Clinical Isolates of Salmonella enterica Serovar Agona Producing NDM-1 Metallo-β-Lactamase: First Report from Pakistan

    PubMed Central

    Khan, Erum; Jabeen, Kauser; Bhawan, Pushpa; Hopkins, Katie L.; Day, Martin; Nasir, Amna; Meunier, Daniele; Woodford, Neil

    2014-01-01

    We report two cases of infantile diarrhea due to multidrug-resistant, NDM-1 metallo-β-lactamase-producing Salmonella enterica serovar Agona from Pakistan. This study alerts toward possible risk of NDM-1 transmission to enteric fever pathogens and encourages microbiologists to consider active screening of carbapenem resistance in nontyphoidal Salmonella isolates. PMID:25378577

  5. Evolutionary trends in two strains of Salmonella enterica subsp. I serovar Enteritidis PT13a that vary in virulence potential.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. I serovar Enteritidis (S. Enteritidis) is the world's leading cause of salmonellosis. Eggs contaminated by apparently healthy hens can result in illness in humans who consume them. Although the incidence of this pathogen within the United States has not been as high as it ...

  6. Inactivation of Salmonella enterica serovar Typhimurium and quality maintenance of cherry tomatoes treated with gaseous essential oils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The antimicrobial activity of the essential oils (EOs) from cinnamon bark, oregano, mustard and of their major components cinnamaldehyde, carvacrol, and allyl isothiocyanate (AIT) were evaluated as a gaseous treatment to reduce Salmonella enterica serovar Typhimurium in vitro and on tomatoes. In dif...

  7. Immersion in antimicrobial solutions reduces Salmonella enterica and Shiga toxin-producing Escherichia coli on beef cheek meat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to determine the effect of immersing beef cheek meat in antimicrobial solutions on the reduction of O157:H7 Shiga toxin–producing Escherichia coli (STEC), non-O157:H7 STEC, and Salmonella enterica. Beef cheek meat was inoculated with O157:H7 STEC, non-O157:H7 STEC, an...

  8. sciS, an icmF Homolog in Salmonella enterica Serovar Typhimurium, Limits Intracellular Replication and Decreases Virulence

    PubMed Central

    Parsons, Duncan A.; Heffron, Fred

    2005-01-01

    Salmonella enterica serovar Typhimurium utilizes macrophages to disseminate from the intestine to deeper tissues within the body. While S. enterica serovar Typhimurium has been shown to kill its host macrophage, it can persist intracellularly beyond 18 h postinfection. To identify factors involved in late stages of infection, we screened a transposon library made in S. enterica serovar Typhimurium for the ability to persist in J774 macrophages at 24 h postinfection. Through this screen, we identified a gene, sciS, found to be homologous to icmF in Legionella pneumophila. icmF, which is required for intracellular multiplication, is conserved in several gram-negative pathogens, and its homolog appears to have been acquired horizontally in S. enterica serovar Typhimurium. We found that an sciS mutant displayed increased intracellular numbers in J774 macrophages when compared to the wild-type strain at 24 h postinfection. sciS was maximally transcribed at 27 h postinfection and is repressed by SsrB, an activator of genes required for promoting intracellular survival. Finally, we demonstrate that an sciS mutant is hypervirulent in mice when administered intragastrically. Taken together, these data indicate a role for SciS in controlling intracellular bacterial levels at later stages of infection and attenuating virulence in a murine host PMID:15972528

  9. Multilocus Sequence Typing Lacks the Discriminatory Ability of Pulsed-Field Gel Electrophoresis for Typing Salmonella enterica Serovar Typhimurium

    PubMed Central

    Fakhr, Mohamed K.; Nolan, Lisa K.; Logue, Catherine M.

    2005-01-01

    Nontyphoidal salmonellae are among the leading causes of food-borne disease in the United States. Because of the importance of Salmonella enterica in food-borne disease, numerous typing methodologies have been developed. Among the several molecular typing methods, pulsed-field gel electrophoresis (PFGE) is currently considered the “gold standard” technique in typing Salmonella. The aim of this study was to compare the discriminatory power of PFGE to multilocus sequence typing (MLST) in typing Salmonella enterica serovar Typhimurium clinical isolates. A total of 85 Salmonella Typhimurium clinical isolates from cattle were used in this study. PFGE using XbaI was performed on the 85 isolates by the Centers for Disease Control and Prevention method, and data were analyzed using the BioNumerics software package. Fifty PFGE profiles were observed among the isolates, and these grouped into three major clusters. For the MLST analysis, the manB, pduF, glnA, and spaM genes were amplified by PCR from the same 85 isolates. DNA sequencing of these four genes, manB, pduF, glnA, and spaM, showed no genetic diversity among the isolates tested, with a 100% identity in nucleotide sequence. Moreover, the DNA sequences of the aforementioned genes showed 100% identity to the sequence reported in GenBank for the S. enterica serovar Typhimurium LT2 strain. Therefore, MLST, using these genes, lacks the discriminatory power of PFGE for typing Salmonella enterica serovar Typhimurium. PMID:15872244

  10. Inactivation of Salmonella enterica and Listeria monocytogenes in cantaloupe puree by high hydrostatic pressure with/without added ascorbic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research was to evaluate and develop a method for inactivation of Salmonella enterica and Listeria monocytogenes in cantaloupe puree (CP) by high hydrostatic pressure (HHP). Cantaloupe being the most netted varieties of melons presents a greater risk of pathogen transmission. ...

  11. COLONIZATION OF ARABIDOPSIS THALIANA WITH SALMONELLA ENTERICA AND ENTEROHEMORRHAGIC ESCHERICHIA COLI 157:H7 AND COMPETITIAN BY ENTEROBACTOR ASBURIAE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enteric pathogens, such as Salmonella enterica and Escherichia coli O157:H7, have been shown to contaminate fresh produce. Under appropriate conditions these bacteria will grow on and invade the plant tissue. We have developed Arabidopsis thaliana (thale cress) as a model system with the intention o...

  12. Molecular profiling: Catecholamine modulation of gene expression in Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Investigations of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium have demonstrated that these bacterial pathogens can respond to the presence of catecholamines including norepinephrine and/or epinephrine in their environment by modulating gene expression and exhibiting various ...

  13. A mutation in the pnp gene encoding polynucleotide phosphorylase attenuates virulence of Salmonella enterica serovar typhimurium in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: The pnp gene encodes polynucleotide phosphorylase, an exoribonuclease involved in RNA degradation. A mutation in the pnp gene was previously identified by our group in a signature-tagged mutagenesis screen designed to search for Salmonella enterica serovar Typhimurium genes required for ...

  14. The alternate sigma factor RpoS protects against silver ion toxicity in Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The alternative sigma factor, RpoS controls the expression of many stress response genes, including genes involved in acid and oxidative stresses. In this study, we demonstrated metal tolerance in S. enterica serovar Typhimurium, and silver ion showed the highest toxicity among the tested metal ions...

  15. Mobilization properties of small ColE1-like plasmids carrying kanamycin resistance gene isolated from Salmonella enterica serotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Previously we isolated and characterized various groups of small kanamycin resistance (KanR) ColE1-like plasmids from different serotypes of Salmonella enterica isolates. These plasmids all carried the aph(3)-I gene encoding the aminoglycoside phosphotransferase responsible for the kanam...

  16. Tetracycline accelerates the temporally-regulated invasion response in specific isolates of multidrug-resistant Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background Multidrug-resistant (MDR) Salmonella is associated with increased morbidity compared to antibiotic-sensitive strains and is an important health and safety concern in both humans and animals. Salmonella enterica serovar Typhimurium is a prevalent cause of foodborne disease, and a consider...

  17. Salmonella enterica Typhimurium infection causes metabolic changes in chicken muscle involving AMPK, fatty acid and insulin/mTOR signaling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Typhimurium (ST) infection of chickens more than a few days old results in asymptomatic cecal colonization with persistent shedding of bacteria. We hypothesized that while the bacteria colonize and persist locally in the cecum, it has systemic effects influencing the phy...

  18. High-throughput Molecular Determination of Salmonella enterica Serovars Use of Multiplex PCR and Capillary Electrophoresis Analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is a zoonotic pathogen and is a leading cause of food-borne illness worldwide. There are over 2,500 serotypes of Salmonella reported. Identification of the serotype is key in defining the etiological agent during an outbreak investigation. In the current study, a high-throughput ...

  19. Motility revertants of opgGH mutants of Salmonella enterica serovar Typhimurium remain defective in mice virulence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We recently demonstrated that osmoregulated periplasmic glucans (OPGs) of Salmonella enterica serovar Typhimurium are required for optimal mouse virulence (Bhagwat et al., 2009. Microbiology 155:229-237). However, lack of OPGs also generated pleiotropic phenotypes such as reduced motility and slower...

  20. Analysis of antimicrobial resistance mechanisms in multi-drug resistant (MDR) Salmonella enterica by high-throughput DNA sequencing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Multi drug resistant (MDR) Salmonella enterica is found in food animals and may consequently pose a risk to humans through food borne transmission. To understand the mechanisms that drive this problem, the genetic elements associated with MDR need to be determined. These MDR elements in ...

  1. Effect of chlorate, molybdate, and shikimic acid on Salmonella enterica serovar Typhimurium in aerobic and anaerobic cultures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chlorate is a bactericide that has potential as a pre-slaughter feed additive to improve food safety of meat products. The aims of the present study were to examine the effects of chlorate (5mM), molybdate (1 mM), and shikimate (0.34 mM) on the growth and chlorate-resistance of Salmonella enterica ...

  2. Evolutionary trends associated with niche specialization as modeled by whole genome analysis of egg-contaminating Salmonella enterica serovar Enteritidis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The mosaic nature of the Salmonella enterica genome facilitates its access to multiple environments. Many large scale genomic events have been described that contribute to the combinatorial complexity of the pathogenic Salmonellae. However, the impact of small scale genetic change occurring at the ...

  3. Comparison of dkgB-linked Intergenic Sequence Ribotyping to DNA Microarray Hydridization for Assigning Serotype to Salmonella Enterica.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Kauffman-White scheme has been used for decades to serotype Salmonella enterica, which is a pervasive and persistent cause of food-borne illness. Analysis of whole genomes of the bacterium has revealed that it is unlikely that the Kauffman-White scheme provides the level of discrimination requir...

  4. Antimicrobial activity of apple, hibiscus, olive, and hydrogen peroxide formulations against Salmonella enterica on organic leafy greens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is one of the most common bacterial pathogens involved in foodborne outbreaks with fresh produce in the last decade. In an effort to discover safe antimicrobials for use on fresh produce, the objective of the present study was to evaluate the effectiveness of different antimicro...

  5. Beta-glucan plus ascorbic acid in neonatal calves modulates immune functions with and without Salmonella enterica serovar Dublin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calves often succumb to Salmonella enterica, Dublin after maternal antibody protection has abated. Enhancement of innate immunity or earlier maturation of adaptive immunity to support vaccinations with dietary immune modulators may be the best option for protection during this vulnerable period. I...

  6. Population genetics of multi-drug resistant (MDR) IncA/C plasmid in Salmonella enterica isolated from animals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Food animals harboring Multi-Drug Resistant (MDR) Salmonella enterica are a potential source for acquisition of zoonotic pathogens. Plasmids (small, self-replicating, extra-chromosomal DNA) are often associated with antimicrobial resistance and plasmids carrying MDR genes have been found to be a maj...

  7. First Report of Human Infection with Salmonella enterica Serovar Apapa Resulting from Exposure to a Pet Lizard▿

    PubMed Central

    Cooke, Fiona J.; De Pinna, Elizabeth; Maguire, Clare; Guha, Simantee; Pickard, Derek J.; Farrington, Mark; Threlfall, E. John

    2009-01-01

    We present the first documented human case of Salmonella enterica serovar Apapa infection, isolated concurrently from a hospital inpatient and a pet lizard. The isolates were identical by biochemical profiling and pulsed-field gel electrophoresis. This rare serotype is known to be associated with reptiles. The current practice for avoiding reptile-associated infections is reviewed. PMID:19535527

  8. Intergenic Sequence Ribotyping using a region neighboring dkgB links genovar to Kauffman-White serotype of Salmonella enterica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty six (36) unique sequences which varied in length from 258bp to 530bp were found for Salmonella enterica strains and isolates that are not present in public databases following BLAST analysis searches for similarity. The sequences were found by application of Intergenic Sequence Ribotyping (IS...

  9. Evolutionary trends in two strains of Salmonella enterica subsp. I serovar Enteritidis PT13a that vary in virulence potential.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. I serovar Enteritidis (S. Enteritidis) is the world's leading cause of salmonellosis. Eggs that are contaminated by apparently healthy hens and that have been improperly cooked can result in illness in humans who consume them. Although the incidence of this pathogen within...

  10. Multilocus sequence typing lacks the discriminatory ability of pulsed-field gel electrophoresis for typing Salmonella enterica serovar Typhimurium.

    PubMed

    Fakhr, Mohamed K; Nolan, Lisa K; Logue, Catherine M

    2005-05-01

    Nontyphoidal salmonellae are among the leading causes of food-borne disease in the United States. Because of the importance of Salmonella enterica in food-borne disease, numerous typing methodologies have been developed. Among the several molecular typing methods, pulsed-field gel electrophoresis (PFGE) is currently considered the "gold standard" technique in typing Salmonella. The aim of this study was to compare the discriminatory power of PFGE to multilocus sequence typing (MLST) in typing Salmonella enterica serovar Typhimurium clinical isolates. A total of 85 Salmonella Typhimurium clinical isolates from cattle were used in this study. PFGE using XbaI was performed on the 85 isolates by the Centers for Disease Control and Prevention method, and data were analyzed using the BioNumerics software package. Fifty PFGE profiles were observed among the isolates, and these grouped into three major clusters. For the MLST analysis, the manB, pduF, glnA, and spaM genes were amplified by PCR from the same 85 isolates. DNA sequencing of these four genes, manB, pduF, glnA, and spaM, showed no genetic diversity among the isolates tested, with a 100% identity in nucleotide sequence. Moreover, the DNA sequences of the aforementioned genes showed 100% identity to the sequence reported in GenBank for the S. enterica serovar Typhimurium LT2 strain. Therefore, MLST, using these genes, lacks the discriminatory power of PFGE for typing Salmonella enterica serovar Typhimurium. PMID:15872244

  11. ANTIMICROBIAL ACTIVITIES OF PHENOLIC BENZALDEHYDES AND BENZOIC ACIDS AGAINST CAMPYLOBACTER JEJUNI, ESCHERICHIA COLI, LISTERIA MONOCYTOGENES, AND SALMONELLA ENTERICA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated the bactericidal activities of 70 benzaldehydes and benzoic acids substituted in the benzene ring with zero, one, two, or three hydroxy (OH) and/or methoxy (OCH3) groups in a pH 7 buffer against Escherichia coli O157:H7, Salmonella enterica, Campylobacter jejuni, and Listeria monocytog...

  12. Characterization of Salmonella enterica isolates from turkeys in commercial processing plants for resistance to antibiotics, disinfectants, and a growth promoter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovars isolated from turkeys in commercial processing plants were characterized for susceptibility to antibiotics, disinfectants, disinfectant components, and the organoarsenical growth promotant 4-hydroxy-3-nitrophenylarsonic acid (3-NHPAA) and its metabolites NaAsO2 (As[III])...

  13. Recipes for Antimicrobial Wine Marinades against Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated bactericidal activities of several antimicrobial wine recipes consisting of red and white wine extracts of oregano leaves with added garlic juice and oregano oil against Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica. Dose-response plots were...

  14. Correlating Blood Immune Parameters and a CCT7 Genetic Variant with the Shedding of Salmonella enterica Serovar Typhimurium in Swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the current study, 40 crossbred pigs were intranasally inoculated with Salmonella enterica serovar Typhimurium and monitored for Salmonella fecal shedding and blood immune parameters at 2, 7, 14 and 20 days post-inoculation (dpi). Using a multivariate permutation test, a positive correlation was...

  15. Instability of Escherichia coli R-factors in Salmonella enterica serovar Typhi involves formation of recombinant composite plasmid structures.

    PubMed

    Mendoza-Medellín, Aurelio; Camacho-Carranza, Rafael; Curiel-Quesada, Everardo

    2012-09-01

    In spite of a well-documented ability of Samonella enterica Typhi strains to receive R factors from Escherichia coli and other enterobacteria, epidemiological data show that Typhi is a rather poor host of antibiotic-resistance genes and in fact, of plasmids, suggesting that most of the plasmids naturally acquired by Typhi strains become unstable and eventually segregate. We have previously reported evidence that each of three plasmids conjugatively transferred to S. enterica Typhi experienced deletion-mediated loss of a resistance determinant before plasmid segregation occurred. We now report that in Typhi strains containing these unstable plasmids a superhelical DNA species of lower mobility is detected, probably representing plasmid dimer structures. Plasmid deletion is a RecA-dependent process since it is not detected in derivatives of a recA1 S. enterica Typhi strain containing the corresponding plasmids, and in such strains we were unable to detect either the low-mobility species. We propose that the deletable segments contain key information for plasmid stability in S. enterica Typhi, possibly a multimer resolution system. PMID:22579995

  16. Serotypes of Salmonella enterica Present in the Internal Organs of Mice Caught On-farm From 1995 – 1998.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    : Salmonella enterica is a persistent and pervasive pathogen that impacts the safety of the food supply, especially in regards to poultry and poultry products. The house mouse Mus musculus is a recognized risk factor for introduction on-farm. More information is needed about Salmonella serotypes tha...

  17. Genomic Comparison of the Closely-Related Salmonella enterica Serovars Enteritidis, Dublin and Gallinarum

    PubMed Central

    Matthews, T. David; Schmieder, Robert; Silva, Genivaldo G. Z.; Busch, Julia; Cassman, Noriko; Dutilh, Bas E.; Green, Dawn; Matlock, Brian; Heffernan, Brian; Olsen, Gary J.; Farris Hanna, Leigh; Schifferli, Dieter M.; Maloy, Stanley; Dinsdale, Elizabeth A.; Edwards, Robert A.

    2015-01-01

    The Salmonella enterica serovars Enteritidis, Dublin, and Gallinarum are closely related but differ in virulence and host range. To identify the genetic elements responsible for these differences and to better understand how these serovars are evolving, we sequenced the genomes of Enteritidis strain LK5 and Dublin strain SARB12 and compared these genomes to the publicly available Enteritidis P125109, Dublin CT 02021853 and Dublin SD3246 genome sequences. We also compared the publicly available Gallinarum genome sequences from biotype Gallinarum 287/91 and Pullorum RKS5078. Using bioinformatic approaches, we identified single nucleotide polymorphisms, insertions, deletions, and differences in prophage and pseudogene content between strains belonging to the same serovar. Through our analysis we also identified several prophage cargo genes and pseudogenes that affect virulence and may contribute to a host-specific, systemic lifestyle. These results strongly argue that the Enteritidis, Dublin and Gallinarum serovars of Salmonella enterica evolve by acquiring new genes through horizontal gene transfer, followed by the formation of pseudogenes. The loss of genes necessary for a gastrointestinal lifestyle ultimately leads to a systemic lifestyle and niche exclusion in the host-specific serovars. PMID:26039056

  18. Genomic Comparison of the Closely-Related Salmonella enterica Serovars Enteritidis, Dublin and Gallinarum.

    PubMed

    Matthews, T David; Schmieder, Robert; Silva, Genivaldo G Z; Busch, Julia; Cassman, Noriko; Dutilh, Bas E; Green, Dawn; Matlock, Brian; Heffernan, Brian; Olsen, Gary J; Farris Hanna, Leigh; Schifferli, Dieter M; Maloy, Stanley; Dinsdale, Elizabeth A; Edwards, Robert A

    2015-01-01

    The Salmonella enterica serovars Enteritidis, Dublin, and Gallinarum are closely related but differ in virulence and host range. To identify the genetic elements responsible for these differences and to better understand how these serovars are evolving, we sequenced the genomes of Enteritidis strain LK5 and Dublin strain SARB12 and compared these genomes to the publicly available Enteritidis P125109, Dublin CT 02021853 and Dublin SD3246 genome sequences. We also compared the publicly available Gallinarum genome sequences from biotype Gallinarum 287/91 and Pullorum RKS5078. Using bioinformatic approaches, we identified single nucleotide polymorphisms, insertions, deletions, and differences in prophage and pseudogene content between strains belonging to the same serovar. Through our analysis we also identified several prophage cargo genes and pseudogenes that affect virulence and may contribute to a host-specific, systemic lifestyle. These results strongly argue that the Enteritidis, Dublin and Gallinarum serovars of Salmonella enterica evolve by acquiring new genes through horizontal gene transfer, followed by the formation of pseudogenes. The loss of genes necessary for a gastrointestinal lifestyle ultimately leads to a systemic lifestyle and niche exclusion in the host-specific serovars. PMID:26039056

  19. Experimental infection of chickens by a flagellated motile strain of Salmonella enterica serovar Gallinarum biovar Gallinarum.

    PubMed

    Lopes, P D; Freitas Neto, O C; Batista, D F A; Denadai, J; Alarcon, M F F; Almeida, A M; Vasconcelos, R O; Setta, A; Barrow, P A; Berchieri, A

    2016-08-01

    Salmonella enterica subsp. enterica serovar Gallinarum biovar Gallinarum (SG) causes fowl typhoid (FT), a septicaemic disease which can result in high mortality in poultry flocks. The absence of flagella in SG is thought to favour systemic invasion, since bacterial recognition via Toll-like receptor (TLR)-5 does not take place during the early stages of FT. In the present study, chicks susceptible to FT were inoculated with a wild type SG (SG) or its flagellated motile derivative (SG Fla(+)). In experiment 1, mortality and clinical signs were assessed, whereas in experiment 2, gross pathology, histopathology, systemic invasion and immune responses were evaluated. SG Fla(+) infection resulted in later development of clinical signs, lower mortality, lower bacterial numbers in the liver and spleen, and less severe pathological changes compared to SG. The CD8(+) T lymphocyte population was higher in the livers of chicks infected with SG at 4 days post-inoculation (dpi). Chicks infected with SG had increased expression of interleukin (IL)-6 mRNA in the caecal tonsil at 1 dpi and increased expression of IL-18 mRNA in the spleen at 4 dpi. In contrast, the CD4(+) T lymphocyte population was higher at 6 dpi in the livers of birds infected with SG Fla(+). Therefore, flagella appeared to modulate the chicken immune response towards a CD4(+) T profile, resulting in more efficient bacterial clearance from systemic sites and milder infection. PMID:27387725

  20. Regulation of DNA phosphorothioate modification in Salmonella enterica by DndB

    PubMed Central

    He, Wei; Huang, Teng; Tang, You; Liu, Yanhua; Wu, Xiaolin; Chen, Si; Chan, Wan; Wang, Yajie; Liu, Xiaoyun; Chen, Shi; Wang, Lianrong

    2015-01-01

    DNA phosphorothioate (PT) modification, in which the non-bridging oxygen of the sugar-phosphate backbone is substituted by sulfur, occurs naturally in diverse bacteria and archaea and is regulated by the DndABCDE proteins. DndABCDE and the restriction cognate DndFGHI constitute a new type of defense system that prevents the invasion of foreign DNA in Salmonella enterica serovar Cerro 87. GAAC/GTTC consensus contexts across genomes were found to possess partial PT modifications even in the presence of restriction activity, indicating the regulation of PT. The abundance of PT in cells must be controlled to suit cellular activities. However, the regulatory mechanism of PT modification has not been characterized. The result here indicated that genomic PT modification in S. enterica is controlled by the transcriptional regulator DndB, which binds to two regions in the promoter, each possessing a 5′-TACGN10CGTA-3′ palindromic motif, to regulate the transcription of dndCDE and its own gene. Site-directed mutagenesis showed that the Cys29 residue of DndB plays a key role in its DNA-binding activity or conformation. Proteomic analysis identified changes to a number of cellular proteins upon up-regulation and loss of PT. Considering the genetic conservation of dnd operons, regulation of PT by DndB might be widespread in diverse organisms. PMID:26190504

  1. Temperature-Sensitive Salmonella enterica Serovar Enteritidis PT13a Expressing Essential Proteins of Psychrophilic Bacteria

    PubMed Central

    Duplantis, Barry N.; Puckett, Stephanie M.; Rosey, Everett L.; Ameiss, Keith A.; Hartman, Angela D.; Pearce, Stephanie C.

    2015-01-01

    Synthetic genes based on deduced amino acid sequences of the NAD-dependent DNA ligase (ligA) and CTP synthetase (pyrG) of psychrophilic bacteria were substituted for their native homologues in the genome of Salmonella enterica serovar Enteritidis phage type 13a (PT13a). The resulting strains were rendered temperature sensitive (TS) and did not revert to temperature resistance at a detectable level. At permissive temperatures, TS strains grew like the parental strain in broth medium and in macrophage-like cells, but their growth was slowed or stopped when they were shifted to a restrictive temperature. When injected into BALB/c mice at the base of the tail, representing a cool site of the body, the strains with restrictive temperatures of 37, 38.5, and 39°C persisted for less than 1 day, 4 to 7 days, and 20 to 28 days, respectively. The wild-type strain persisted at the site of inoculation for at least 28 days. The wild-type strain, but not the TS strains, was also found in spleen-plus-liver homogenates within 1 day of inoculation of the tail and was detectable in these organs for at least 28 days. Intramuscular vaccination of White Leghorn chickens with the PT13a strain carrying the psychrophilic pyrG gene provided some protection against colonization of the reproductive tract and induced an anti-S. enterica antibody response. PMID:26187965

  2. Single passage in mouse organs enhances the survival and spread of Salmonella enterica.

    PubMed

    Dybowski, Richard; Restif, Olivier; Goupy, Alexandre; Maskell, Duncan J; Mastroeni, Piero; Grant, Andrew J

    2015-12-01

    Intravenous inoculation of Salmonella enterica serovar Typhimurium into mice is a prime experimental model of invasive salmonellosis. The use of wild-type isogenic tagged strains (WITS) in this system has revealed that bacteria undergo independent bottlenecks in the liver and spleen before establishing a systemic infection. We recently showed that those bacteria that survived the bottleneck exhibited enhanced growth when transferred to naive mice. In this study, we set out to disentangle the components of this in vivo adaptation by inoculating mice with WITS grown either in vitro or in vivo. We developed an original method to estimate the replication and killing rates of bacteria from experimental data, which involved solving the probability-generating function of a non-homogeneous birth-death-immigration process. This revealed a low initial mortality in bacteria obtained from a donor animal. Next, an analysis of WITS distributions in the livers and spleens of recipient animals indicated that in vivo-passaged bacteria started spreading between organs earlier than in vitro-grown bacteria. These results further our understanding of the influence of passage in a host on the fitness and virulence of Salmonella enterica and represent an advance in the power of investigation on the patterns and mechanisms of host-pathogen interactions. PMID:26701880

  3. Diverse distribution of Toxin-Antitoxin II systems in Salmonella enterica serovars

    PubMed Central

    Di Cesare, Andrea; Losasso, Carmen; Barco, Lisa; Eckert, Ester M.; Conficoni, Daniele; Sarasini, Giulia; Corno, Gianluca; Ricci, Antonia

    2016-01-01

    Type II Toxin-Antitoxin systems (TAs), known for their presence in virulent and antibiotic resistant bacterial strains, were recently identified in Salmonella enterica isolates. However, the relationships between the presence of TAs (ccdAB and vapBC) and the epidemiological and genetic features of different non-typhoidal Salmonella serovars are largely unknown, reducing our understanding of the ecological success of different serovars. Salmonella enterica isolates from different sources, belonging to different serovars and epidemiologically unrelated according to ERIC profiles, were investigated for the presence of type II TAs, plasmid content, and antibiotic resistance. The results showed the ubiquitous presence of the vapBC gene in all the investigated Salmonella isolates, but a diverse distribution of ccdAB, which was detected in the most widespread Salmonella serovars, only. Analysis of the plasmid toxin ccdB translated sequence of four selected Salmonella isolates showed the presence of the amino acid substitution R99W, known to impede in vitro the lethal effect of CcdB toxin in the absence of its cognate antitoxin CcdA. These findings suggest a direct role of the TAs in promoting adaptability and persistence of the most prevalent Salmonella serovars, thus implying a wider eco-physiological role for these type II TAs. PMID:27357537

  4. Genomic comparison of the closely-related Salmonella enterica serovars enteritidis, dublin and gallinarum

    DOE PAGESBeta

    Matthews, T. David; Schmieder, Robert; Silva, Genivaldo G. Z.; Busch, Julia; Cassman, Noriko; Dutilh, Bas E.; Green, Dawn; Matlock, Brian; Heffernan, Brian; Olsen, Gary J.; et al

    2015-06-03

    The Salmonella enterica serovars Enteritidis, Dublin, and Gallinarum are closely related but differ in virulence and host range. To identify the genetic elements responsible for these differences and to better understand how these serovars are evolving, we sequenced the genomes of Enteritidis strain LK5 and Dublin strain SARB12 and compared these genomes to the publicly available Enteritidis P125109, Dublin CT 02021853 and Dublin SD3246 genome sequences. We also compared the publicly available Gallinarum genome sequences from biotype Gallinarum 287/91 and Pullorum RKS5078. Using bioinformatic approaches, we identified single nucleotide polymorphisms, insertions, deletions, and differences in prophage and pseudogene content betweenmore » strains belonging to the same serovar. Through our analysis we also identified several prophage cargo genes and pseudogenes that affect virulence and may contribute to a host-specific, systemic lifestyle. These results strongly argue that the Enteritidis, Dublin and Gallinarum serovars of Salmonella enterica evolve by acquiring new genes through horizontal gene transfer, followed by the formation of pseudogenes. The loss of genes necessary for a gastrointestinal lifestyle ultimately leads to a systemic lifestyle and niche exclusion in the host-specific serovars.« less

  5. Chromosomal Rearrangements in Salmonella enterica Serovar Typhi Strains Isolated from Asymptomatic Human Carriers

    PubMed Central

    Matthews, T. David; Rabsch, Wolfgang; Maloy, Stanley

    2011-01-01

    ABSTRACT Host-specific serovars of Salmonella enterica often have large-scale chromosomal rearrangements that occur by recombination between rrn operons. Two hypotheses have been proposed to explain these rearrangements: (i) replichore imbalance from horizontal gene transfer drives the rearrangements to restore balance, or (ii) the rearrangements are a consequence of the host-specific lifestyle. Although recent evidence has refuted the replichore balance hypothesis, there has been no direct evidence for the lifestyle hypothesis. To test this hypothesis, we determined the rrn arrangement type for 20 Salmonella enterica serovar Typhi strains obtained from human carriers at periodic intervals over multiple years. These strains were also phage typed and analyzed for rearrangements that occurred over long-term storage versus routine culturing. Strains isolated from the same carrier at different time points often exhibited different arrangement types. Furthermore, colonies isolated directly from the Dorset egg slants used to store the strains also had different arrangement types. In contrast, colonies that were repeatedly cultured always had the same arrangement type. Estimated replichore balance of isolated strains did not improve over time, and some of the rearrangements resulted in decreased replicore balance. Our results support the hypothesis that the restricted lifestyle of host-specific Salmonella is responsible for the frequent chromosomal rearrangements in these serovars. PMID:21652779

  6. Endogenous Synthesis of 2-Aminoacrylate Contributes to Cysteine Sensitivity in Salmonella enterica

    PubMed Central

    Ernst, Dustin C.; Lambrecht, Jennifer A.; Schomer, Rebecca A.

    2014-01-01

    RidA, the archetype member of the widely conserved RidA/YER057c/UK114 family of proteins, prevents reactive enamine/imine intermediates from accumulating in Salmonella enterica by catalyzing their hydrolysis to stable keto acid products. In the absence of RidA, endogenous 2-aminoacrylate persists in the cellular environment long enough to damage a growing list of essential metabolic enzymes. Prior studies have focused on the dehydration of serine by the pyridoxal 5′-phosphate (PLP)-dependent serine/threonine dehydratases, IlvA and TdcB, as sources of endogenous 2-aminoacrylate. The current study describes an additional source of endogenous 2-aminoacrylate derived from cysteine. The results of in vivo analysis show that the cysteine sensitivity of a ridA strain is contingent upon CdsH, the predominant cysteine desulfhydrase in S. enterica. The impact of cysteine on 2-aminoacrylate accumulation is shown to be unaffected by the presence of serine/threonine dehydratases, revealing another mechanism of endogenous 2-aminoacrylate production. Experiments in vitro suggest that 2-aminoacrylate is released from CdsH following cysteine desulfhydration, resulting in an unbound aminoacrylate substrate for RidA. This work expands our understanding of the role played by RidA in preventing enamine stress resulting from multiple normal metabolic processes. PMID:25002544

  7. Salmonella Enterica Serovar Typhimurium BipA Exhibits Two Distinct Ribosome Binding Modes

    SciTech Connect

    deLivron, M.; Robinson, V

    2008-01-01

    BipA is a highly conserved prokaryotic GTPase that functions to influence numerous cellular processes in bacteria. In Escherichia coli and Salmonella enterica serovar Typhimurium, BipA has been implicated in controlling bacterial motility, modulating attachment and effacement processes, and upregulating the expression of virulence genes and is also responsible for avoidance of host defense mechanisms. In addition, BipA is thought to be involved in bacterial stress responses, such as those associated with virulence, temperature, and symbiosis. Thus, BipA is necessary for securing bacterial survival and successful invasion of the host. Steady-state kinetic analysis and pelleting assays were used to assess the GTPase and ribosome-binding properties of S. enterica BipA. Under normal bacterial growth, BipA associates with the ribosome in the GTP-bound state. However, using sucrose density gradients, we demonstrate that the association of BipA and the ribosome is altered under stress conditions in bacteria similar to those experienced during virulence. The data show that this differential binding is brought about by the presence of ppGpp, an alarmone that signals the onset of stress-related events in bacteria.

  8. Evaluation of Salmonella enterica Type III Secretion System Effector Proteins as Carriers for Heterologous Vaccine Antigens

    PubMed Central

    Hegazy, Wael Abdel Halim; Xu, Xin; Metelitsa, Leonid

    2012-01-01

    Live attenuated strains of Salmonella enterica have a high potential as carriers of recombinant vaccines. The type III secretion system (T3SS)-dependent translocation of S. enterica can be deployed for delivery of heterologous antigens to antigen-presenting cells. Here we investigated the efficacy of various effector proteins of the Salmonella pathogenicity island (SPI2)-encoded T3SS for the translocation of model antigens and elicitation of immune responses. The SPI2 T3SS effector proteins SifA, SteC, SseL, SseJ, and SseF share an endosomal membrane-associated subcellular localization after translocation. We observed that all effector proteins could be used to translocate fusion proteins with the model antigens ovalbumin and listeriolysin into the cytosol of host cells. Under in vitro conditions, fusion proteins with SseJ and SteC stimulated T-cell responses that were superior to those triggered by fusion proteins with SseF. However, in mice vaccinated with Salmonella carrier strains, only fusion proteins based on SseJ or SifA elicited potent T-cell responses. These data demonstrate that the selection of an optimal SPI2 effector protein for T3SS-mediated translocation is a critical parameter for the rational design of effective Salmonella-based recombinant vaccines. PMID:22252866

  9. Pathogenicity of Salmonella enterica in Caenorhabditis elegans relies on disseminated oxidative stress in the infected host.

    PubMed

    Sem, XiaoHui; Rhen, Mikael

    2012-01-01

    Feeding Caenorhabditis elegans with Salmonella enterica serovar Typhimurium significantly shortens the lifespan of the nematode. S. Typhimurium-infected C. elegans, stained with 2',7'-dichlorodihydrofluorescein diacetate which fluoresces upon exposure to reactive oxygen species, revealed intestinal luminal staining that along with the time of infection progressed to a strong staining in the hypodermal tissues of the nematode. Still, we could not detect invasion beyond the nematode's intestinal epithelium at any stage of the infection. A similar dispersion of oxidative response was also noted in nematodes infected with S. Dublin, but not with non-pathogenic Escherichia coli or the defined pathogen Burkholderia thailandensis. Addition of catalase or the reductant ascorbic acid significantly restored the lifespan of S. Typhimurium-infected nematodes. Mutational inactivation of the bacterial thioredoxin 1 resulted in total ablation of the hypodermal oxidative response to infection, and in a strong attenuation of virulence. Virulence of the thioredoxin 1 mutant was restored by trans-complementation with redox-active variants of thioredoxin 1 or, surprisingly, by exposing the thioredoxin 1 mutant to sublethal concentrations of the disulphide catalyst copper chloride prior to infection. In summary, our observations define a new aspect in virulence of S. enterica that apparently does not involve the classical invasive or intracellular phenotype of the pathogen, but that depends on the ability to provoke overwhelming systemic oxidative stress in the host through the redox activity of bacterial thioredoxin 1. PMID:23028994

  10. Characterization of a pore-forming cytotoxin expressed by Salmonella enterica serovars typhi and paratyphi A.

    PubMed

    Oscarsson, Jan; Westermark, Marie; Löfdahl, Sven; Olsen, Björn; Palmgren, Helena; Mizunoe, Yoshimitsu; Wai, Sun Nyunt; Uhlin, Bernt Eric

    2002-10-01

    Cytolysin A (ClyA) is a pore-forming cytotoxic protein encoded by the clyA gene that has been characterized so far only in Escherichia coli. Using DNA sequence analysis and PCR, we established that clyA is conserved in the human-specific typhoid Salmonella enterica serovars Typhi and Paratyphi A and that the entire clyA gene locus is absent in many other S. enterica serovars, including Typhimurium. The gene products, designated ClyA(STy) and ClyA(SPa), show >/=90% amino acid identity to E. coli cytolysin A, ClyA(EC), and they are immunogenically related. The Salmonella proteins showed a pore-forming activity and are hence functional homologues to ClyA(EC). The chromosomal clyA(STy) gene locus was expressed at detectable levels in the serovar Typhi strains S2369/96 and S1112/97. Furthermore, in the serovar Typhi vaccine strain Ty21a, expression of clyA(STy) reached phenotypic levels, as detected on blood agar plates. The hemolytic phenotype was abolished by the introduction of an in-frame deletion in the clyA(STy) chromosomal locus of Ty21a. Transcomplementation of the mutant with a cloned clyA(STy) gene restored the hemolytic phenotype. To our knowledge, Ty21a is the first reported phenotypically hemolytic Salmonella strain in which the genetic determinant has been identified. PMID:12228306

  11. Physiological and Immunological Regulations in Caenorhabditis elegans Infected with Salmonella enterica serovar Typhi.

    PubMed

    Sivamaruthi, Bhagavathi Sundaram; Balamurugan, Krishnaswamy

    2014-03-01

    Studies pertaining to Salmonella enterica serovar Typhimurium infection by utilizing model systems failed to mimic the essential aspects of immunity induced by Salmonella enterica serovar Typhi, as the determinants of innate immunity are distinct. The present study investigated the physiological and innate immune responses of S. Typhi infected Caenorhabditis elegans and also explored the Ty21a mediated immune enhancement in C. elegans. Ty21a is a known live vaccine for typhoidal infection in human beings. Physiological responses of C. elegans infected with S. Typhi assessed by survival and behavioral assays revealed that S. Typhi caused host mortality by persistent infection. However, Ty21a exposure to C. elegans was not harmful. Ty21a pre-exposed C. elegans, exhibited significant resistance against S. Typhi infection. Elevated accumulation of S. Typhi inside the infected host was observed when compared to Ty21a exposures. Transcript analysis of candidate innate immune gene (clec-60, clec-87, lys-7, ilys-3, scl-2, cpr-2, F08G5.6, atf-7, age-1, bec-1 and daf-16) regulations in the host during S. Typhi infection have been assessed through qPCR analysis to understand the activation of immune signaling pathways during S. Typhi infections. Gene silencing approaches confirmed that clec-60 and clec-87 has a major role in the defense system of C. elegans during S. Typhi infection. In conclusion, the study revealed that preconditioning of host with Ty21a protects against subsequent S. Typhi infection. PMID:24426167

  12. Diverse distribution of Toxin-Antitoxin II systems in Salmonella enterica serovars.

    PubMed

    Di Cesare, Andrea; Losasso, Carmen; Barco, Lisa; Eckert, Ester M; Conficoni, Daniele; Sarasini, Giulia; Corno, Gianluca; Ricci, Antonia

    2016-01-01

    Type II Toxin-Antitoxin systems (TAs), known for their presence in virulent and antibiotic resistant bacterial strains, were recently identified in Salmonella enterica isolates. However, the relationships between the presence of TAs (ccdAB and vapBC) and the epidemiological and genetic features of different non-typhoidal Salmonella serovars are largely unknown, reducing our understanding of the ecological success of different serovars. Salmonella enterica isolates from different sources, belonging to different serovars and epidemiologically unrelated according to ERIC profiles, were investigated for the presence of type II TAs, plasmid content, and antibiotic resistance. The results showed the ubiquitous presence of the vapBC gene in all the investigated Salmonella isolates, but a diverse distribution of ccdAB, which was detected in the most widespread Salmonella serovars, only. Analysis of the plasmid toxin ccdB translated sequence of four selected Salmonella isolates showed the presence of the amino acid substitution R99W, known to impede in vitro the lethal effect of CcdB toxin in the absence of its cognate antitoxin CcdA. These findings suggest a direct role of the TAs in promoting adaptability and persistence of the most prevalent Salmonella serovars, thus implying a wider eco-physiological role for these type II TAs. PMID:27357537

  13. Population Dynamics of Salmonella enterica Serotypes in Commercial Egg and Poultry Production ▿

    PubMed Central

    Foley, Steven L.; Nayak, Rajesh; Hanning, Irene B.; Johnson, Timothy J.; Han, Jing; Ricke, Steven C.

    2011-01-01

    Fresh and processed poultry have been frequently implicated in cases of human salmonellosis. Furthermore, increased consumption of meat and poultry has increased the potential for exposure to Salmonella enterica. While advances have been made in reducing the prevalence and frequency of Salmonella contamination in processed poultry, there is mounting pressure on commercial growers to prevent and/or eliminate these human pathogens in preharvest production facilities. Several factors contribute to Salmonella colonization in commercial poultry, including the serovar and the infectious dose. In the early 1900s, Salmonella enterica serovars Pullorum and Gallinarum caused widespread diseases in poultry, but vaccination and other voluntary programs helped eradicate pullorum disease and fowl typhoid from commercial flocks. However, the niche created by the eradication of these serovars was likely filled by S. Enteritidis, which proliferated in the bird populations. While this pathogen remains a significant problem in commercial egg and poultry production, its prevalence among poultry has been declining since the 1990s. Coinciding with the decrease of S. Enteritidis, S. Heidelberg and S. Kentucky have emerged as the predominant serovars in commercial broilers. In this review, we have highlighted bacterial genetic and host-related factors that may contribute to such shifts in Salmonella populations in commercial poultry and intervention strategies that could limit their colonization. PMID:21571882

  14. Assessment of antibiotic resistance phenotype and integrons in Salmonella enterica serovar Typhimurium isolated from swine.

    PubMed

    Rayamajhi, Nabin; Kang, Sang Gyun; Kang, Mi Lan; Lee, Hee Soo; Park, Kyung Yoon; Yoo, Han Sang

    2008-10-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) isolated and identified from swine were subjected for the analysis of antibiotic resistance pattern and clinically important class 1 and 2 integrons. In addition, S. Typhimurium isolates exhibiting ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, tetracycline and florfenicol (ACSSuTF) resistance pattern as described in most Salmonella enterica serotype Typhimurium definitive type 104 (DT104) were characterized by polymerase chain reaction. All the isolates were resistant to more than four antibiotics and showed the highest resistance to streptomycin (94.1%), followed by tetracycline (90.1%), ampicillin (64.7%), chloramphenicol (56.8%) and gentamicin (54.9%). MIC value for the ten isolates ranged between 0.125-2 mug/ml for ciprofloxacin. Among the beta-lactams used, only one of the isolate exhibited resistance to ceftiofur (MIC 8 microg/ml). Sixty eight percent of these multi drug resistance (MDR) S. Typhimurium isolates carried clinically important class 1 integron with 1kb (aadA) and/or 2kb (dhfrXII-orfF-aadA2) resistance gene cassettes. This study reports the increasing trend of multi drug resistance (MDR) S. Typhimurium with clinically important class 1 integron in pigs. In addition, emergence of the ACSSuTF-type resistance in S. Typhimurium PT other than DT104 may limit the use of resistance gene markers in its detection methods by PCR. PMID:18981675

  15. Regulation of fucose and 1,2-propanediol utilization by Salmonella enterica serovar Typhimurium

    PubMed Central

    Staib, Lena; Fuchs, Thilo M.

    2015-01-01

    After ingestion, Salmonella enterica serovar Typhimurium (S. Typhimurium) encounters a densely populated, competitive environment in the gastrointestinal tract. To escape nutrient limitation caused by the intestinal microbiota, this pathogen has acquired specific metabolic traits to use compounds that are not metabolized by the commensal bacteria. For example, the utilization of 1,2-propanediol (1,2-PD), a product of the fermentation of L-fucose, which is present in foods of herbal origin and is also a terminal sugar of gut mucins. Under anaerobic conditions and in the presence of tetrathionate, 1,2-PD can serve as an energy source for S. Typhimurium. Comprehensive database analysis revealed that the 1,2-PD and fucose utilization operons are present in all S. enterica serovars sequenced thus far. The operon, consisting of 21 genes, is expressed as a single polycistronic mRNA. As demonstrated here, 1,2-PD was formed and further used when S. Typhimurium strain 14028 was grown with L-fucose, and the gene fucA encoding L-fuculose-1-phosphate aldolase was required for this growth. Using promoter fusions, we monitored the expression of the propanediol utilization operon that was induced at very low concentrations of 1,2-PD and was inhibited by the presence of D-glucose. PMID:26528264

  16. Incidence and growth of Salmonella enterica on the peel and pulp of avocado (Persea americana) and custard apple (Annona squamosa).

    PubMed

    Rezende, Ana Carolina B; Crucello, Juliana; Moreira, Rafael C; Silva, Beatriz S; Sant'Ana, Anderson S

    2016-10-17

    The aim of this study was to assess the incidence and to estimate the growth kinetic parameters (maximum growth rate, μ; lag time, λ; and maximum population, κ) of Salmonella on the peel and pulp of avocado (Perseaamericana var. americana) and custard apple (Annona squamosa L.) as affected by temperature (10-30°C). The incidence of Salmonella was assessed on the peel and pulp of the fruits (n=200 of each fruit), separately, totalizing 800 analyses. Only three samples of custard apple pulp were positive for Salmonella enterica and the three isolates recovered belonged to serotype S. Typhimurium. Salmonella was not recovered from avocado and custard apple peels and from avocado pulp. Generally, the substrate (pulp or peel) of growth did not affect μ values of S. enterica (p>0.05). Very similar μ values were found for S. enterica inoculated in custard apple and avocado. S. enterica presented the highest λ in the peel of the fruits. The growth of S. enterica resulted in larger λ in custard apple in comparison to avocado. For example, the λ of S. enterica in the pulp of custard apple and avocado were 47.0±0.78h and 10.0±3.78h, respectively. The lowest values of κ were obtained at the lower storage temperature conditions (10°C). For instance, κ values of 3.7±0.06log CFU/g and 2.9±0.03log CFU/g were obtained from the growth of S. enterica in avocado and custard apple pulps at 10°C (p<0.05), respectively. On the other hand, at 30°C, κ values were 6.5±0.25log CFU/g and 6.5±0.05log CFU/g, respectively. Significantly higher κ were obtained from the growth of S. enterica in the pulp than in the peel of the fruits (p<0.05). For instance, the growth of S. enterica in the pulp of avocado led to a κ value of 6.5±0.25log CFU/g, while in the peel led to a κ value of 4.6±0.23log CFU/g (p<0.05). In general, growth kinetic parameters indicated that avocado comprises a better substrate than custard apple for the growth of S. enterica. The square root model

  17. Diversity of multidrug-resistant salmonella enterica strains associated with cattle at harvest in the United States.

    PubMed

    Brichta-Harhay, Dayna M; Arthur, Terrance M; Bosilevac, Joseph M; Kalchayanand, Norasak; Shackelford, Steven D; Wheeler, Tommy L; Koohmaraie, Mohammad

    2011-03-01

    The prevalence and diversity of multidrug-resistant (MDR) Salmonella enterica strains associated with cattle at harvest in the United States were examined. Hides and carcasses of cattle were sampled at processing plants (n = 6) located in four geographically distant regions from July 2005 to April 2006. The mean prevalences of Salmonella on hides, preevisceration carcasses (immediately after hide removal), and postintervention carcasses (in the chiller and after the full complement of interventions) were 89.6%, 50.2%, and 0.8%, respectively. The values for MDR Salmonella enterica strains (defined as those resistant to two or more antimicrobials) as percentages of Salmonella prevalence were 16.7% (95% confidence interval [CI], 8.3 to 25.1%; median percent prevalence, 6.9%), 11.7% (95% CI, 4.4 to 19.0%; median, 4.8%), and 0.33% (95% CI, -0.3 to 0.70%; median, 0%), respectively. In this study, 16,218 Salmonella hide and carcass isolates were screened for antimicrobial resistance. Of these, 978 (6.0%) unique MDR S. enterica isolates were identified and serotyped and their XbaI pulsed-field gel electrophoresis (PFGE) profiles determined. The predominant MDR S. enterica serotypes observed were Newport (53.1%), Typhimurium (16.6%), and Uganda (10.9%). Differences in MDR S. enterica prevalence were detected, and PFGE analysis revealed both epidemic clusters (profiles found in plants in multiple regions/seasons) and endemic clusters (profiles observed in plants in limited regions/seasons) within several of the MDR serotypes examined. Despite these differences, multiple-hurdle processing interventions employed at all plants were found to be quite effective and decreased Salmonella carcass contamination by 98.4% (95% CI, 97.6 to 99.7%). PMID:21239549

  18. Diversity of Multidrug-Resistant Salmonella enterica Strains Associated with Cattle at Harvest in the United States ▿

    PubMed Central

    Brichta-Harhay, Dayna M.; Arthur, Terrance M.; Bosilevac, Joseph M.; Kalchayanand, Norasak; Shackelford, Steven D.; Wheeler, Tommy L.; Koohmaraie , Mohammad

    2011-01-01

    The prevalence and diversity of multidrug-resistant (MDR) Salmonella enterica strains associated with cattle at harvest in the United States were examined. Hides and carcasses of cattle were sampled at processing plants (n = 6) located in four geographically distant regions from July 2005 to April 2006. The mean prevalences of Salmonella on hides, preevisceration carcasses (immediately after hide removal), and postintervention carcasses (in the chiller and after the full complement of interventions) were 89.6%, 50.2%, and 0.8%, respectively. The values for MDR Salmonella enterica strains (defined as those resistant to two or more antimicrobials) as percentages of Salmonella prevalence were 16.7% (95% confidence interval [CI], 8.3 to 25.1%; median percent prevalence, 6.9%), 11.7% (95% CI, 4.4 to 19.0%; median, 4.8%), and 0.33% (95% CI, −0.3 to 0.70%; median, 0%), respectively. In this study, 16,218 Salmonella hide and carcass isolates were screened for antimicrobial resistance. Of these, 978 (6.0%) unique MDR S. enterica isolates were identified and serotyped and their XbaI pulsed-field gel electrophoresis (PFGE) profiles determined. The predominant MDR S. enterica serotypes observed were Newport (53.1%), Typhimurium (16.6%), and Uganda (10.9%). Differences in MDR S. enterica prevalence were detected, and PFGE analysis revealed both epidemic clusters (profiles found in plants in multiple regions/seasons) and endemic clusters (profiles observed in plants in limited regions/seasons) within several of the MDR serotypes examined. Despite these differences, multiple-hurdle processing interventions employed at all plants were found to be quite effective and decreased Salmonella carcass contamination by 98.4% (95% CI, 97.6 to 99.7%). PMID:21239549

  19. Development of Microarray and Multiplex Polymerase Chain Reaction Assays for Identification of Serovars and Virulence Genes in Salmonella enterica of Human or Animal Origin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is an important enteric pathogen consisting of many serotypes that can cause severe clinical diseases in animals and humans. Rapid identification of Salmonella isolates is especially important for epidemiological monitoring and controlling outbreaks of disease. Although immunolo...

  20. A comparative study of thermal and acid inactivation kinetics in fruit juices of Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Senftenberg grown at acidic conditions.

    PubMed

    Alvarez-Ordóñez, Avelino; Fernández, Ana; Bernardo, Ana; López, Mercedes

    2009-11-01

    Acid and heat inactivation in orange and apple juices of Salmonella enterica serovar Typhimurium Colección Española de Cultivos Tipo (i.e., Spanish Type Culture Collection) 443 (CECT 443) (Salmonella Typhimurium) and S. enterica serovar Senftenberg CECT 4384 (Salmonella Senftenberg) grown in buffered brain heart infusion (pH 7.0) and acidified brain heart infusion up to pH 4.5 with acetic, citric, lactic, and hydrochloric acids was evaluated. Acid adaptation induced an adaptive response that increased the subsequent resistance to extreme pH conditions (pH 2.5) and to heat, although the magnitude of these responses differed between the two isolates and fruit juices. The acid resistance in orange juice for acid-adapted cells (D-values of 28.3-34.5 min for Salmonella Senftenberg and 30.0-39.2 min for Salmonella Typhimurium) resulted to be about two to three times higher than that corresponding to non-acid-adapted cells. In apple juice, acid-adapted Salmonella Senftenberg cells survived better than those of Salmonella Typhimurium, obtaining mean D-values of 114.8 +/- 12.3 and 41.9 +/- 2.5 min, respectively. The thermotolerance of non-acid-adapted Salmonella Typhimurium in orange (D(58)-value: 0.028 min) and apple juices (D(58)-value: 0.10 min) was approximately double for acid-adapted cells. This cross-protection to heat was more strongly expressed in Salmonella Senftenberg. D(58)-values obtained for non-acid-adapted cells in orange (0.11 min) and apple juices (0.19 min) increased approximately 10 and 5 times, respectively, after their growth in acidified media. The conditions prevailing during bacterial growth and heat treatment did not significantly influence the z-values observed (6.0 +/- 0.3 degrees C for Salmonella Typhimurium and 7.0 +/- 0.3 degrees C for Salmonella Senftenberg). The enhanced acid resistance found for both isolates could enable them to survive for prolonged time periods in the gastrointestinal tract, increasing the risk of illness. Further, it

  1. Complete genome sequencing of a multidrug-resistant and human-invasive Salmonella enterica serovar Typhimurium strain of the emerging sequence type 213 genotype

    SciTech Connect

    Calva, Edmundo; Silva, Claudia; Zaidi, Mussaret B.; Sanchez-Flores, Alejandro; Estrada, Karel; Silva, Genivaldo G. Z.; Soto-Jiménez, Luz M.; Wiesner, Magdalena; Fernández-Mora, Marcos; Edwards, Robert A.; Vinuesa, Pablo

    2015-06-18

    Salmonella enterica subsp. enterica serovar Typhimurium strain YU39 was isolated in 2005 in the state of Yucatán, Mexico, from a human systemic infection. The YU39 strain is representative of the multidrug-resistant emergent sequence type 213 (ST213) genotype. The YU39 complete genome is composed of a chromosome and seven plasmids.

  2. Effectiveness of a novel spontaneous carvacrol nanoemulsion against Salmonella enterica Enteritidis and Escherichia coli O157:H7 on contaminated mung bean and alfalfa seeds.

    PubMed

    Landry, Kyle S; Chang, Yuhua; McClements, David Julian; McLandsborough, Lynne

    2014-09-18

    Outbreaks of foodborne illness from consumption of sprouts have been linked to contaminated seeds prior to germination. Due to the long sprouting period at ambient temperatures and high humidity, germinating seeds contaminated with low pathogen levels (0.1logCFU/g) can result in sprouts with high numbers (≥10(8)CFU/g) of pathogens. Currently, the recommended treatment method involves soaking seeds in 20,000ppm (2%) calcium hypochlorite prior to germination. In this study, an alternative treatment involving soaking seeds in a carvacrol nanoemulsion was tested for its efficacy against Salmonella enterica subspecies enterica serovar Enteritidis (ATCC BAA-1045) or EGFP expressing E. coli O157:H7 (ATCC 42895) contaminated mung bean and alfalfa seeds. The antimicrobial treatment was performed by soaking inoculated seed batches in the spontaneous nanoemulsion (4000 or 8000ppm) for 30 or 60min. The spontaneous nanoemulsion was formed by titrating the oil phase (carvacrol and medium chain triglycerides) and water-soluble surfactant (Tween 80®) into sodium citrate buffer. Following treatment, the numbers of surviving cells were determined by suspending the seeds in TSB and performing plate counts and/or Most Probable Number (MPN) enumeration. Treated seeds were sprouted and tested for the presence of the appropriate pathogen. This treatment successfully inactivated low levels (2 and 3logCFU/g) of S. Enteritidis and E. coli on either seed types when soaked for either 30 or 60min at nanoemulsion concentrations corresponding to 4000 (0.4%) or 8000 (0.8%) ppm carvacrol. Inoculated alfalfa seeds treated with 4000ppm nanoemulsion, required a 60min treatment time to show a similar 2-3 log reduction. Complete inactivation was confirmed by germinating treated seeds and performing microbiological testing. Total sprout yield was not compromised by any of the tested treatments. These results show that carvacrol nanoemulsions may be an alternative antimicrobial treatment method for

  3. Antimicrobial Resistance of Salmonella enterica Isolates from Tonsil and Jejunum with Lymph Node Tissues of Slaughtered Swine in Metro Manila, Philippines

    PubMed Central

    Ng, Kamela Charmaine S.; Rivera, Windell L.

    2014-01-01

    Due to frequent antibiotic exposure, swine is now recognized as potential risk in disseminating drug-resistant Salmonella enterica strains. This study thus subjected 20 randomly selected S. enterica isolates from tonsil and jejunum with lymph node (JLN) tissues of swine slaughtered in Metro Manila, Philippines, to VITEK 2 antimicrobial susceptibility testing (AST). The test revealed all 20 isolates had resistance to at least one antimicrobial agent, in which highest occurrence of resistance was to amikacin (100%), cefazolin (100%), cefuroxime (100%), cefuroxime axetil (100%), cefoxitin (100%), and gentamicin (100%), followed by ampicillin (50%), and then by sulfamethoxazole trimethoprim (30%). Three multidrug-resistant (MDR) isolates were detected. The sole S. enterica serotype Enteritidis isolate showed resistance to 12 different antibiotics including ceftazidime, ceftriaxone, amikacin, gentamicin, and tigecycline. This study is the first to report worldwide on the novel resistance to tigecycline of MDR S. enterica serotype Enteritidis isolated from swine tonsil tissues. This finding poses huge therapeutic challenge since MDR S. enterica infections are associated with increased rate of hospitalization or death. Thus, continual regulation of antimicrobial use in food animals and prediction of resistant serotypes are crucial to limit the spread of MDR S. enterica isolates among hogs and humans. PMID:24724034

  4. Isolation of Salmonella enterica and serologic reactivity to Leptospira interrogans in opossums (Didelphis virginiana) from Yucatán, México.

    PubMed

    Ruiz-Pina, Hugo Antonio; Puc-Franco, Miguel Angel; Flores-Abuxapqui, Javier; Vado-Solis, Ignacio; Cardenas-Marrufo, María Fidelia

    2002-01-01

    The presence of Salmonella enterica and serologic evidence of infection by Leptospira interrogans, were detected in the opossum Didelphis virginiana in a semi-urban locality of the Yucatán State, México. Ninety-one opossums were captured during the period April 1996 and May 1998. From a total of 17 feces samples, four Salmonella enterica subsp. enterica serotypes (Sandiego, Newport, Anatum, and Minnesota), and one Salmonella enterica subsp. arizonae serovar O44:Z4,Z23:- were isolated. Some opossums presented mixed infections. From 81 sera samples, four (4.9%) were positive to antibodies to Leptospira serovars pomona and wolfii. Both animals infected with Salmonella enterica and those serologically positive to Leptospira interrogans were captured in peridomestic habitat. Opossums infected with Salmonella enterica, were captured in dry season, and those seropositive to Leptospira interrogans during the rainy season. The implications of infection and reactivity of these zoonotic pathogens in D. virginiana in the Yucatan state are briefly discussed. PMID:12219118

  5. Circulating γδ T Cells in Response to Salmonella enterica Serovar Enteritidis Exposure in Chickens

    PubMed Central

    Berndt, Angela; Pieper, Jana; Methner, Ulrich

    2006-01-01

    γδ T cells are considered crucial to the outcome of various infectious diseases. The present study was undertaken to characterize γδ (T-cell receptor 1+ [TCR1+]) T cells phenotypically and functionally in avian immune response. Day-old chicks were orally immunized with Salmonella enterica serovar Enteritidis live vaccine or S. enterica serovar Enteritidis wild-type strain and infected using the S. enterica serovar Enteritidis wild-type strain on day 44 of life. Between days 3 and 71, peripheral blood was examined flow cytometrically for the occurrence of γδ T-cell subpopulations differentiated by the expression of T-cell antigens. Three different TCR1+ cell populations were found to display considerable variation regarding CD8α antigen expression: (i) CD8α+high TCR1+ cells, (ii) CD8α+dim TCR1+ cells, and (iii) CD8α− TCR1+ cells. While most of the CD8α+high TCR1+ cells expressed the CD8αβ heterodimeric antigen, the majority of the CD8α+dim TCR1+ cells were found to express the CD8αα homodimeric form. After immunization, a significant increase of CD8αα+high γδ T cells was observed within the CD8α+high TCR1+ cell population. Quantitative reverse transcription-PCR revealed reduced interleukin-7 receptor α (IL-7Rα) and Bcl-x expression and elevated IL-2Rα mRNA expression of the CD8αα+high γδ T cells. Immunohistochemical analysis demonstrated a significant increase of CD8α+ and TCR1+ cells in the cecum and spleen and a decreased percentage of CD8β+ T cells in the spleen after Salmonella immunization. After infection of immunized animals, immune reactions were restricted to intestinal tissue. The study showed that Salmonella immunization of very young chicks is accompanied by an increase of CD8αα+high γδ T cells in peripheral blood, which are probably activated, and thus represent an important factor for the development of a protective immune response to Salmonella organisms in chickens. PMID:16790770

  6. RpoE may promote flagellar gene expression in Salmonella enterica serovar typhi under hyperosmotic stress.

    PubMed

    Du, Hong; Sheng, Xiumei; Zhang, Haifang; Zou, Xin; Ni, Bin; Xu, Shungao; Zhu, Xueming; Xu, Huaxi; Huang, Xinxiang

    2011-02-01

    Salmonella enterica serovar Typhi z66 positive strain contains a fljBA-like operon on a linear plasmid. The operon contains the gene fljB:z66 which encodes the z66 antigen. RpoE is a sigma factor σ(E) that initiates transcription of a series of genes in Escherichia and Salmonella under environmental stresses. To investigate whether the gene fljB:z66 is regulated by RpoE (σ(E)), a rpoE deletion mutant of S. enterica serovar Typhi (ΔrpoE) was prepared in this study. The defective motility of the ΔrpoE was confirmed firstly. Transcriptional expression of flagellar genes was screened using a genomic DNA microarray. Some class-2 and most class-3 flagellar genes were downregulated in the ΔrpoE after 30 min of hyperosmotic stress. The expression of fliA and fljB:z66, a class-2 flagellar gene and a class-3 flagellar gene, obviously decreased; however, expression of the class-1 flagellar genes flhDC did not change obviously in the ΔrpoE compared to the wild-type strain in the same conditions. Results of quantitative real-time PCR (qRT-PCR) showed that the expression levels of fliA and fljB:z66 in the ΔrpoE after 30 min of hyperosmotic stress decreased about five and eightfold, respectively, compared to the wild-type strain. Similar results were observed at 120 min of hyperosmotic stress. Western blotting and qRT-PCR analysis showed that expression of fliA and fljB:z66 was significantly increased after supplemental expression of rpoE with a recombinant plasmid pBADrpoE in the ΔrpoE strain. These results demonstrated that RpoE promoted the expression of class-3 flagellar genes and it might be performed by initiating the expression of fliA in S. enterica serovar Typhi under hyperosmotic stress. PMID:20717675

  7. The STM4195 Gene Product (PanS) Transports Coenzyme A Precursors in Salmonella enterica

    PubMed Central

    Ernst, Dustin C.

    2015-01-01

    ABSTRACT Coenzyme A (CoA) is a ubiquitous coenzyme involved in fundamental metabolic processes. CoA is synthesized from pantothenic acid by a pathway that is largely conserved among bacteria and eukaryotes and consists of five enzymatic steps. While higher organisms, including humans, must scavenge pantothenate from the environment, most bacteria and plants are capable of de novo pantothenate biosynthesis. In Salmonella enterica, precursors to pantothenate can be salvaged, but subsequent intermediates are not transported due to their phosphorylated state, and thus the pathway from pantothenate to CoA is considered essential. Genetic analyses identified the STM4195 gene product of Salmonella enterica serovar Typhimurium as a transporter of pantothenate precursors, ketopantoate and pantoate and, to a lesser extent, pantothenate. Further results indicated that STM4195 transports a product of CoA degradation that serves as a precursor to CoA and enters the biosynthetic pathway between PanC and CoaBC (dfp). The relevant CoA derivative is distinguishable from pantothenate, pantetheine, and pantethine and has spectral properties indicating the adenine moiety of CoA is intact. Taken together, the results presented here provide evidence of a transport mechanism for the uptake of ketopantoate, pantoate, and pantothenate and demonstrate a role for STM4195 in the salvage of a CoA derivative of unknown structure. The STM4195 gene is renamed panS to reflect participation in pantothenate salvage that was uncovered herein. IMPORTANCE This manuscript describes a transporter for two pantothenate precursors in addition to the existence and transport of a salvageable coenzyme A (CoA) derivative. Specifically, these studies defined a function for an STM protein in S. enterica that was distinct from the annotated role and led to its designation as PanS (pantothenate salvage). The presence of a salvageable CoA derivative and a transporter for it suggests the possibility that this

  8. Cross-sectional Study Examining Salmonella enterica Carriage in Subiliac Lymph Nodes of Cull and Feedlot Cattle at Harvest

    PubMed Central

    Gragg, Sara E.; Loneragan, Guy H.; Brashears, Mindy M.; Arthur, Terrance M.; Bosilevac, Joseph M.; Kalchayanand, Norasak; Wang, Rong; Schmidt, John W.; Brooks, J. Chance; Shackelford, Steven D.; Wheeler, Tommy L.; Brown, Tyson R.; Edrington, Thomas S.

    2013-01-01

    Abstract Bovine peripheral lymph nodes (LNs), including subiliac LNs, have been identified as a potential source of human exposure to Salmonella enterica, when adipose trim containing these nodes is incorporated into ground beef. In order to gain a better understanding of the burden of S. enterica in peripheral LNs of feedlot and cull cattle, a cross-sectional study was undertaken in which 3327 subiliac LNs were collected from cattle at harvest in seven plants, located in three geographically distinct regions of the United States. Samples were collected in three seasons: Fall 2010, Winter/Spring 2011, and Summer/Fall 2011. A convenience sample of 76 LNs per day, 2 days per season (approximately 1 month apart), was collected per plant, from carcasses held in the cooler for no less than 24 h. Every 10th carcass half on a rail was sampled, in an attempt to avoid oversampling any single cohort of cattle. Median point estimates of S. enterica contamination were generally low (1.3%); however, median Salmonella prevalence was found to be greater in subiliac LNs of feedlot cattle (11.8%) compared to those of cull cattle (0.65%). Enumeration analysis of a subset of 618 feedlot cattle LNs showed that 67% of those harboring S. enterica (97 of 144) did so at concentrations ranging from <0.1 to 1.8 log10 CFU/g, while 33% carried a higher burden of S. enterica, with levels ranging from 1.9 to >3.8 log10 CFU/g. Serotyping of S. enterica isolated identified 24 serotypes, with the majority being Montevideo (44.0%) and Anatum (24.8%). Antimicrobial susceptibility phenotypes were determined for all isolates, and the majority (86.1%) were pansusceptible; however, multidrug-resistant isolates (8.3%) were also occasionally observed. As Salmonella contained within LNs are protected from carcass interventions, research is needed to define opportunities for mitigating the risk of Salmonella contamination in LNs of apparently healthy cattle. PMID:23566273

  9. Analysis and construction of pathogenicity island regulatory pathways in Salmonella enterica serovar Typhi.

    PubMed

    Ong, Su Yean; Ng, Fui Ling; Badai, Siti Suriawati; Yuryev, Anton; Alam, Maqsudul

    2010-01-01

    Signal transduction through protein-protein interactions and protein modifications are the main mechanisms controlling many biological processes. Here we described the implementation of MedScan information extraction technology and Pathway Studio software (Ariadne Genomics Inc.) to create a Salmonella specific molecular interaction database. Using the database, we have constructed several signal transduction pathways in Salmonella enterica serovar Typhi which causes Typhoid Fever, a major health threat especially in developing countries. S. Typhi has several pathogenicity islands that control rapid switching between different phenotypes including adhesion and colonization, invasion, intracellular survival, proliferation, and biofilm formation in response to environmental changes. Understanding of the detailed mechanism for S. Typhi survival in host cells is necessary for development of efficient detection and treatment of this pathogen. The constructed pathways were validated using publically available gene expression microarray data for Salmonella. PMID:20861532

  10. Outbreaks of monophasic Salmonella enterica serovar 4,[5],12:i:- in Luxembourg, 2006.

    PubMed

    Mossong, J; Marques, P; Ragimbeau, C; Huberty-Krau, P; Losch, S; Meyer, G; Moris, G; Strottner, C; Rabsch, W; Schneider, F

    2007-06-01

    A monophasic Salmonella enterica serovar 4,[5],12:i:- phage type DT193 emerged as the dominant serovar in Luxembourg in 2006, when it caused two major outbreaks involving 133 laboratory-confirmed human cases, 24 hospitalisations, and one death. The outbreak strain had an uncommon pulsed-field gel electrophoresis pattern STYMXB.0031 and antibiotic resistance profile ASSuT. A high proportion of cases were clustered in institutions for the elderly and in day-care centers. Strains identical to the outbreak strain were recovered from two control meals, a nappy changing table, retail sausages and caecal porcine samples at an abattoir. Locally produced pork meat is strongly suspected to have been the vehicle for the outbreaks, although the precise mechanisms remain unclear. PMID:17991400

  11. An infection-relevant transcriptomic compendium for Salmonella enterica Serovar Typhimurium.

    PubMed

    Kröger, Carsten; Colgan, Aoife; Srikumar, Shabarinath; Händler, Kristian; Sivasankaran, Sathesh K; Hammarlöf, Disa L; Canals, Rocío; Grissom, Joe E; Conway, Tyrrell; Hokamp, Karsten; Hinton, Jay C D

    2013-12-11

    Bacterial transcriptional networks consist of hundreds of transcription factors and thousands of promoters. However, the true complexity of transcription in a bacterial pathogen and the effect of the environments encountered during infection remain to be established. We present a simplified approach for global promoter identification in bacteria using RNA-seq-based transcriptomic analyses of 22 distinct infection-relevant environmental conditions. Individual RNA samples were combined to identify most of the 3,838 Salmonella enterica serovar Typhimurium promoters in just two RNA-seq runs. Individual in vitro conditions stimulated characteristic transcriptional signatures, and the suite of 22 conditions induced transcription of 86% of all S. Typhimurium genes. We highlight the environmental conditions that induce the Salmonella pathogenicity islands and present a small RNA expression landscape of 280 sRNAs. This publicly available compendium of environmentally controlled expression of every transcriptional feature of S. Typhimurium constitutes a useful resource for the bacterial research community. PMID:24331466

  12. Microgravity as a novel environmental signal affecting Salmonella enterica serovar Typhimurium virulence

    NASA Technical Reports Server (NTRS)

    Nickerson, C. A.; Ott, C. M.; Mister, S. J.; Morrow, B. J.; Burns-Keliher, L.; Pierson, D. L.

    2000-01-01

    The effects of spaceflight on the infectious disease process have only been studied at the level of the host immune response and indicate a blunting of the immune mechanism in humans and animals. Accordingly, it is necessary to assess potential changes in microbial virulence associated with spaceflight which may impact the probability of in-flight infectious disease. In this study, we investigated the effect of altered gravitational vectors on Salmonella virulence in mice. Salmonella enterica serovar Typhimurium grown under modeled microgravity (MMG) were more virulent and were recovered in higher numbers from the murine spleen and liver following oral infection compared to organisms grown under normal gravity. Furthermore, MMG-grown salmonellae were more resistant to acid stress and macrophage killing and exhibited significant differences in protein synthesis than did normal-gravity-grown cells. Our results indicate that the environment created by simulated microgravity represents a novel environmental regulatory factor of Salmonella virulence.

  13. Same species, different diseases: how and why typhoidal and non-typhoidal Salmonella enterica serovars differ

    PubMed Central

    Gal-Mor, Ohad; Boyle, Erin C.; Grassl, Guntram A.

    2014-01-01

    Human infections by the bacterial pathogen Salmonella enterica represent major disease burdens worldwide. This highly ubiquitous species consists of more than 2600 different serovars that can be divided into typhoidal and non-typhoidal Salmonella (NTS) serovars. Despite their genetic similarity, these two groups elicit very different diseases and distinct immune responses in humans. Comparative analyses of the genomes of multiple Salmonella serovars have begun to explain the basis of the variation in disease manifestations. Recent advances in modeling both enteric fever and intestinal gastroenteritis in mice will facilitate investigation into both the bacterial- and host-mediated mechanisms involved in salmonelloses. Understanding the genetic and molecular mechanisms responsible for differences in disease outcome will augment our understanding of Salmonella pathogenesis, host immunity, and the molecular basis of host specificity. This review outlines the differences in epidemiology, clinical manifestations, and the human immune response to typhoidal and NTS infections and summarizes the current thinking on why these differences might exist. PMID:25136336

  14. First Case of Lung Abscess due to Salmonella enterica Serovar Abony in an Immunocompetent Adult Patient.

    PubMed

    Pitiriga, Vassiliki; Dendrinos, John; Nikitiadis, Emanuel; Vrioni, Georgia; Tsakris, Athanassios

    2016-01-01

    In healthy individuals, nontyphoidal Salmonella species predominantly cause a self-limited form of gastroenteritis, while they infrequently invade or cause fatal disease. Extraintestinal manifestations of nontyphoidal Salmonella infections are not common and mainly occur among individuals with specific risk factors; among them, focal lung infection is a rare complication caused by nontyphoidal Salmonella strains typically occurring in immunocompromised patients with prior lung disease. We describe the first case of a localized lung abscess formation in an immunocompetent healthy female adult due to Salmonella enterica serovar Abony. The patient underwent lobectomy and was discharged after full clinical recovery. This case report highlights nontyphoidal Salmonellae infections as a potential causative agent of pleuropulmonary infections even in immunocompetent healthy adults. PMID:27429814

  15. Neutrophils Are a Source of Gamma Interferon during Acute Salmonella enterica Serovar Typhimurium Colitis

    PubMed Central

    Spees, Alanna M.; Kingsbury, Dawn D.; Wangdi, Tamding; Xavier, Mariana N.; Tsolis, Renée M.

    2014-01-01

    Gamma interferon (IFN-γ) is an important driver of intestinal inflammation during colitis caused by Salmonella enterica serovar Typhimurium. Here we used the mouse colitis model to investigate the cellular sources of IFN-γ in the cecal mucosa during the acute phase of an S. Typhimurium infection. While IFN-γ staining was detected in T cells, NK cells, and inflammatory monocytes at 2 days after infection, the majority of IFN-γ-positive cells in the cecal mucosa were neutrophils. Furthermore, neutrophil depletion blunted mucosal Ifng expression and reduced the severity of intestinal lesions during S. Typhimurium infection. We conclude that neutrophils are a prominent cellular source of IFN-γ during the innate phase of S. Typhimurium-induced colitis. PMID:24421037

  16. YjgF is required for isoleucine biosynthesis when Salmonella enterica is grown on pyruvate medium.

    PubMed

    Christopherson, Melissa R; Schmitz, G E; Downs, Diana M

    2008-04-01

    The YjgF/YER057c/UK114 family of proteins is conserved across the three domains of life, yet no biochemical function has been clearly defined for any member of this family. In Salmonella enterica, a deletion of yjgF results in a requirement for isoleucine when the mutant strain is grown in glucose-serine or pyruvate medium. Feedback inhibition of IlvA is required for the curative effect of isoleucine on glucose-serine medium. On pyruvate medium, yjgF mutants are unable to synthesize enough isoleucine for growth. From this study, we conclude that the isoleucine requirement of a yjgF mutant on pyruvate is a consequence of the decreased transaminase B (IlvE) activity that has previously been characterized in these mutants. PMID:18296521

  17. Microarray-Based Detection of Salmonella enterica Serovar Enteritidis Genes Involved in Chicken Reproductive Tract Colonization

    PubMed Central

    Raspoet, R.; Appia-Ayme, C.; Shearer, N.; Martel, A.; Pasmans, F.; Haesebrouck, F.; Ducatelle, R.; Thompson, A.

    2014-01-01

    Salmonella enterica serovar Enteritidis has developed the potential to contaminate table eggs internally, by colonization of the chicken reproductive tract and internalization in the forming egg. The serotype Enteritidis has developed mechanisms to colonize the chicken oviduct more successfully than other serotypes. Until now, the strategies exploited by Salmonella Enteritidis to do so have remained largely unknown. For that reason, a microarray-based transposon library screen was used to identify genes that are essential for the persistence of Salmonella Enteritidis inside primary chicken oviduct gland cells in vitro and inside the reproductive tract in vivo. A total of 81 genes with a potential role in persistence in both the oviduct cells and the oviduct tissue were identified. Major groups of importance include the Salmonella pathogenicity islands 1 and 2, genes involved in stress responses, cell wall, and lipopolysaccharide structure, and the region-of-difference genomic islands 9, 21, and 40. PMID:25281378

  18. Survival of Salmonella enterica in Aerated and Nonaerated Wastewaters from Dairy Lagoons

    PubMed Central

    Ravva, Subbarao V.; Sarreal, Chester Z.

    2014-01-01

    Salmonella is the most commonly identified foodborne pathogen in produce, meat and poultry. Cattle are known reservoirs of Salmonella and the pathogen excreted in feces ends up in manure flush lagoons. Salmonella enterica survival was monitored in wastewater from on-site holding lagoons equipped or not with circulating aerators at two dairies. All strains had poor survival rates and none proliferated in waters from aerated or settling lagoons. Populations of all three Salmonella serovars declined rapidly with decimal reduction times (D) of <2 days in aerated microcosms prepared from lagoon equipped with circulators. Populations of Salmonella decreased significantly in aerated microcosms (D = 4.2 d) compared to nonaerated waters (D = 7.4 d) and in summer (D = 3.4 d) compared to winter (D = 9.0 d). We propose holding the wastewater for sufficient decimal reduction cycles in lagoons to yield pathogen-free nutrient-rich water for crop irrigations and fertilization. PMID:25358096

  19. First Case of Lung Abscess due to Salmonella enterica Serovar Abony in an Immunocompetent Adult Patient

    PubMed Central

    Dendrinos, John; Nikitiadis, Emanuel; Vrioni, Georgia; Tsakris, Athanassios

    2016-01-01

    In healthy individuals, nontyphoidal Salmonella species predominantly cause a self-limited form of gastroenteritis, while they infrequently invade or cause fatal disease. Extraintestinal manifestations of nontyphoidal Salmonella infections are not common and mainly occur among individuals with specific risk factors; among them, focal lung infection is a rare complication caused by nontyphoidal Salmonella strains typically occurring in immunocompromised patients with prior lung disease. We describe the first case of a localized lung abscess formation in an immunocompetent healthy female adult due to Salmonella enterica serovar Abony. The patient underwent lobectomy and was discharged after full clinical recovery. This case report highlights nontyphoidal Salmonellae infections as a potential causative agent of pleuropulmonary infections even in immunocompetent healthy adults. PMID:27429814

  20. Diversity and antimicrobial susceptibility of Salmonella enterica serovars isolated from pig farms in Ibadan, Nigeria.

    PubMed

    Fashae, Kayode; Hendriksen, Rene S

    2014-01-01

    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 serotyped and their antimicrobial susceptibility was determined. PMQR genes were screened by polymerase chain reaction. The 229 Salmonella isolates were made of 50 serovars predominated by rare serovars Salmonella Give (n = 36; 15.7 %), Salmonella Brancaster (n = 17; 7.4 %), Salmonella Colindale (n = 15; 6.6 %), Salmonella Elisaberthville (n = 13; 5.7 %), Salmonella Hillingdon (n = 13; 5.7 %), and Salmonella Kingston (n = 13; 5.7 %). The most widely distributed serovars among the farms were Salmonella Give (six farms) and Salmonella Elisaberthville (six farms). Resistance to chloramphenicol, sulfonamides, nalidixic acid, streptomycin, and tetracycline ranged from 11.6 % (n = 26) to 22.8 % (n = 51). Resistance ciprofloxacin and gentamicin was low (n = 2; 0.9 %). Multiply resistant isolates included Salmonella Kentucky, the most resistant serovar. qnrB19 was found in two isolates of Salmonella Corvallis and one isolate of Salmonella Larochelle, respectively, while qnrS1 was found in two isolates of Salmonella Derby. Other PMQR genes were not detected. Pigs constitute an important source of diverse Salmonella serovars in Ibadan. The isolates were more resistant to old antimicrobials with some multiple resistant. Control measures and regulation of antimicrobials are warranted. PMID:23893398

  1. Distribution and Characterization of Salmonella enterica Isolates from Irrigation Ponds in the Southeastern United States.

    PubMed

    Luo, Zhiyao; Gu, Ganyu; Ginn, Amber; Giurcanu, Mihai C; Adams, Paige; Vellidis, George; van Bruggen, Ariena H C; Danyluk, Michelle D; Wright, Anita C

    2015-07-01

    Irrigation water has been implicated as a likely source of produce contamination by Salmonella enterica. Therefore, the distribution of S. enterica was surveyed monthly in irrigation ponds (n = 10) located within a prime agricultural region in southern Georgia and northern Florida. All ponds and 28.2% of all samples (n = 635) were positive for Salmonella, with an overall geometric mean concentration (0.26 most probable number [MPN]/liter) that was relatively low compared to prior reports for rivers in this region. Salmonella peaks were seasonal; the levels correlated with increased temperature and rainfall (P < 0.05). The numbers and occurrence were significantly higher in water (0.32 MPN/liter and 37% of samples) than in sediment (0.22 MPN/liter and 17% of samples) but did not vary with depth. Representative isolates (n = 185) from different ponds, sample types, and seasons were examined for resistance to 15 different antibiotics; most strains were resistant to streptomycin (98.9%), while 20% were multidrug resistant (MDR) for 2 to 6 antibiotics. DiversiLab repetitive extragenic palindromic-element sequence-based PCR (rep-PCR) revealed genetic diversity and showed 43 genotypes among 191 isolates, as defined by >95% similarity. The genotypes did not partition by pond, season, or sample type. Genetic similarity to known serotypes indicated Hadar, Montevideo, and Newport as the most prevalent. All ponds achieved the current safety standards for generic Escherichia coli in agricultural water, and regression modeling showed that the E. coli level was a significant predictor for the probability of Salmonella occurrence. However, persistent populations of Salmonella were widely distributed in irrigation ponds, and the associated risks for produce contamination and subsequent human exposure are unknown, supporting continued surveillance of this pathogen in agricultural settings. PMID:25911476

  2. Distribution and Characterization of Salmonella enterica Isolates from Irrigation Ponds in the Southeastern United States

    PubMed Central

    Luo, Zhiyao; Gu, Ganyu; Ginn, Amber; Giurcanu, Mihai C.; Adams, Paige; Vellidis, George; van Bruggen, Ariena H. C.; Danyluk, Michelle D.

    2015-01-01

    Irrigation water has been implicated as a likely source of produce contamination by Salmonella enterica. Therefore, the distribution of S. enterica was surveyed monthly in irrigation ponds (n = 10) located within a prime agricultural region in southern Georgia and northern Florida. All ponds and 28.2% of all samples (n = 635) were positive for Salmonella, with an overall geometric mean concentration (0.26 most probable number [MPN]/liter) that was relatively low compared to prior reports for rivers in this region. Salmonella peaks were seasonal; the levels correlated with increased temperature and rainfall (P < 0.05). The numbers and occurrence were significantly higher in water (0.32 MPN/liter and 37% of samples) than in sediment (0.22 MPN/liter and 17% of samples) but did not vary with depth. Representative isolates (n = 185) from different ponds, sample types, and seasons were examined for resistance to 15 different antibiotics; most strains were resistant to streptomycin (98.9%), while 20% were multidrug resistant (MDR) for 2 to 6 antibiotics. DiversiLab repetitive extragenic palindromic-element sequence-based PCR (rep-PCR) revealed genetic diversity and showed 43 genotypes among 191 isolates, as defined by >95% similarity. The genotypes did not partition by pond, season, or sample type. Genetic similarity to known serotypes indicated Hadar, Montevideo, and Newport as the most prevalent. All ponds achieved the current safety standards for generic Escherichia coli in agricultural water, and regression modeling showed that the E. coli level was a significant predictor for the probability of Salmonella occurrence. However, persistent populations of Salmonella were widely distributed in irrigation ponds, and the associated risks for produce contamination and subsequent human exposure are unknown, supporting continued surveillance of this pathogen in agricultural settings. PMID:25911476

  3. Safety and immunogenicity of an attenuated Salmonella enterica serovar Paratyphi A vaccine candidate.

    PubMed

    Xiong, Kun; Chen, Zhijin; Zhu, Chunyue; Li, Jianhua; Hu, Xiaomei; Rao, Xiancai; Cong, Yanguang

    2015-09-01

    Enteric fever caused by Salmonella enterica serovar Paratyphi A has progressively increased in recent years and became a global health issue. Currently licensed typhoid vaccines do not confer adequate cross-immunoprotection against S. Paratyphi A infection. Therefore, vaccines specifically against enteric fever caused by S. Paratyphi A are urgently needed. In the present study, an attenuated vaccine strain was constructed from S. Paratyphi A CMCC50093 by the deletions of aroC and yncD. The obtained strain SPADD01 showed reduced survival within THP-1 cells and less bacterial burden in spleens and livers of infected mice compared with the wild-type strain. The 50% lethal doses of SPADD01 and the wild-type strain were assessed using a murine infection model. The virulence of SPADD01 is approximately 40,000-fold less than that of the wild-type strain. In addition, SPADD01 showed an excellent immunogenicity in mouse model. Single intranasal inoculation elicited striking humoral and mucosal immune responses in mice and yielded effective protection against lethal challenge of the wild-type strain. A high level of cross-reactive humoral immune response against LPS of Salmonella enterica serovar Typhi was also detected in immunized mice. However, SPADD01 vaccination only conferred a low level of cross-protection against S. Typhi. Our data suggest that SPADD01 is a promising vaccine candidate against S. Paratyphi A infection and deserves further evaluation in clinical trial. To date, no study has demonstrated a good cross-protection between serovars of S. Typhi and S. Paratyphi A, suggesting that the dominant protective antigens of both serovars are likely different and need to be defined in future study. PMID:26239100

  4. LeuO is a global regulator of gene expression in Salmonella enterica serovar Typhimurium.

    PubMed

    Dillon, Shane C; Espinosa, Elena; Hokamp, Karsten; Ussery, David W; Casadesús, Josep; Dorman, Charles J

    2012-09-01

    We report the first investigation of the binding of the Salmonella enterica LeuO LysR-type transcription regulator to its genomic targets in vivo. Chromatin-immunoprecipitation-on-chip identified 178 LeuO binding sites on the chromosome of S. enterica serovar Typhimurium strain SL1344. These sites were distributed across both the core and the horizontally acquired genome, and included housekeeping genes and genes known to contribute to virulence. Sixty-eight LeuO targets were co-bound by the global repressor protein, H-NS. Thus, while LeuO may function as an H-NS antagonist, these functions are unlikely to involve displacement of H-NS. RNA polymerase bound 173 of the 178 LeuO targets, consistent with LeuO being a transcription regulator. Thus, LeuO targets two classes of genes, those that are bound by H-NS and those that are not bound by H-NS. LeuO binding site analysis revealed a logo conforming to the TN(11) A motif common to LysR-type transcription factors. It differed in some details from a motif that we composed for Escherichia coli LeuO binding sites; 1263 and 1094 LeuO binding site locations were predicted in the S. Typhimurium SL1344 and E. coli MG1655 genomes respectively. Despite differences in motif composition, many LeuO target genes were common to both species. Thus, LeuO is likely to be a more important global regulator than previously suspected. PMID:22804842

  5. Unique lipid anchor attaches Vi antigen capsule to the surface of Salmonella enterica serovar Typhi.

    PubMed

    Liston, Sean D; Ovchinnikova, Olga G; Whitfield, Chris

    2016-06-14

    Polysaccharide capsules are surface structures that are critical for the virulence of many Gram-negative pathogenic bacteria. Salmonella enterica serovar Typhi is the etiological agent of typhoid fever. It produces a capsular polysaccharide known as "Vi antigen," which is composed of nonstoichiometrically O-acetylated α-1,4-linked N-acetylgalactosaminuronic acid residues. This glycan is a component of currently available vaccines. The genetic locus for Vi antigen production is also present in soil bacteria belonging to the genus Achromobacter Vi antigen assembly follows a widespread general strategy with a characteristic glycan export step involving an ATP-binding cassette transporter. However, Vi antigen producers lack the enzymes that build the conserved terminal glycolipid characterizing other capsules using this method. Achromobacter species possess a Vi antigen-specific depolymerase enzyme missing in S enterica Typhi, and we exploited this enzyme to isolate acylated Vi antigen termini. Mass spectrometry analysis revealed a reducing terminal N-acetylhexosamine residue modified with two β-hydroxyl acyl chains. This terminal structure resembles one half of lipid A, the hydrophobic portion of bacterial lipopolysaccharides. The VexE protein encoded in the Vi antigen biosynthesis locus shares similarity with LpxL, an acyltransferase from lipid A biosynthesis. In the absence of VexE, Vi antigen is produced, but its physical properties are altered, its export is impaired, and a Vi capsule structure is not assembled on the cell surface. The structure of the lipidated terminus dictates a unique assembly mechanism and has potential implications in pathogenesis and vaccine production. PMID:27226298

  6. Multidrug resistance in Salmonella enterica serotype Typhimurium from humans in France (1993 to 2003).

    PubMed

    Weill, François-Xavier; Guesnier, Françoise; Guibert, Véronique; Timinouni, Mohammed; Demartin, Marie; Polomack, Lucette; Grimont, Patrick A D

    2006-03-01

    The aim of this study was to determine the distribution of the antimicrobial resistance phenotypes (R types), the phage types and XbaI-pulsed-field gel electrophoresis (PFGE) types, the genes coding for resistance to beta-lactams and to quinolones, and the class 1 integrons among a representative sample of Salmonella enterica serotype Typhimurium isolates collected from humans in 2002 through the French National Reference Center for Salmonella (NRC-Salm) network. The trends in the evolution of antimicrobial resistance of serotype Typhimurium were reviewed by using NRC-Salm data from 1993, 1997, 2000, and 2003. In 2002, 3,998 isolates of serotype Typhimurium were registered at the NRC-Salm among 11,775 serotyped S. enterica isolates (34%). The most common multiple antibiotic resistance pattern was resistance to amoxicillin, chloramphenicol, streptomycin and spectinomycin, sulfonamides, and tetracycline (ACSSpSuTe R type), with 156 isolates (48.8%). One isolate resistant to extended-spectrum cephalosporins due to the production of TEM-52 extended-spectrum beta-lactamase was detected (0.3%), and one multidrug-resistant isolate was highly resistant to ciprofloxacin (MIC > 32 mg/liter). We found that 57.2% of the isolates tested belonged to the DT104 clone. The main resistance pattern of DT104 isolates was R type ACSSpSuTe (83.2%). However, evolutionary changes have occurred within DT104, involving both loss (variants of Salmonella genomic island 1) and acquisition of genes for drug resistance to trimethoprim or to quinolones. PFGE profile X1 was the most prevalent (74.5%) among DT104 isolates, indicating the need to use a more discriminatory subtyping method for such isolates. Global data from the NRC-Salm suggested that DT104 was the main cause of multidrug resistance in serotype Typhimurium from humans from at least 1997 to 2003, with a roughly stable prevalence during this period. PMID:16517842

  7. Novel Salmonella enterica serovar Typhimurium protein that is indispensable for virulence and intracellular replication.

    PubMed

    van der Straaten, T; van Diepen, A; Kwappenberg, K; van Voorden, S; Franken, K; Janssen, R; Kusters, J G; Granger, D L; van Dissel, J T

    2001-12-01

    Upon contact with host cells, the intracellular pathogen Salmonella enterica serovar Typhimurium promotes its uptake, targeting, and survival in intracellular niches. In this process, the bacterium evades the microbicidal effector mechanisms of the macrophage, including oxygen intermediates. This study reports the phenotypic and genotypic characterization of an S. enterica serovar Typhimurium mutant that is hypersusceptible to superoxide. The susceptible phenotype is due to a MudJ insertion-inactivation of a previously undescribed Salmonella gene designated sspJ that is located between 54.4 and 64 min of the Salmonella chromosome and encodes a 392-amino-acid protein. In vivo, upon intraperitoneal injection of 10(4) to 10(7) bacteria in C3H/HeN and 10(1) to 10(4) bacteria in BALB/c mice, the mutant strain was less virulent than the wild type. Consistent with this finding, during the first hour after ingestion by macrophage-like J774 and RAW264.7 cells in vitro, the intracellular killing of the strain carrying sspJ::MudJ is enhanced fivefold over that of wild-type microorganisms. Wild-type salmonellae displayed significant intracellular replication during the first 24 h after uptake, but sspJ::MudJ mutants failed to do so. This phenotype could be restored to that of the wild type by sspJ complementation. The SspJ protein is found in the cytoplasmic membrane and periplasmic space. Amino acid sequence homology analysis did reveal a leader sequence and putative pyrroloquinoline quinone-binding domains, but no putative protein function. We excluded the possibility that SspJ is a scavenger of superoxide or has superoxide dismutase activity. PMID:11705915

  8. Association between Indoor Environmental Contamination by Salmonella enterica and Contamination of Eggs on Layer Farms

    PubMed Central

    Gole, Vaibhav C.; Torok, Valeria; Sexton, Margaret; Caraguel, Charles G. B.

    2014-01-01

    This study involves longitudinal and point-in-time surveys of Salmonella carriage and environmental contamination on two commercial cage layer farms positive for Salmonella enterica subsp. enterica serovar Typhimurium (flock A age, 32 weeks; flock B age, 34 weeks). Salmonella-positive fecal, egg belt, and dust samples were all unconditionally associated with eggshells testing positive for Salmonella. The odds of an eggshell testing positive for Salmonella were 91.8, 61.5, and 18.2 times higher when fecal, egg belt, and dust samples, respectively, tested positive for Salmonella. The agreement between the culture-based methods and real-time PCR on preenriched broths for detecting Salmonella was almost perfect for eggshell (observed agreement, 99.19%; kappa coefficient, 0.94) and egg belt samples (observed agreement, 95%; kappa coefficient, 0.88), and it was substantial for fecal (observed agreement, 87.14%; kappa coefficient, 0.47) and floor dust samples (observed agreement, 80.61%; kappa coefficient, 0.58). A 1-log increase in the load of Salmonella detected in the fecal, egg belt, and floor dust samples resulted in 35%, 43%, and 45% increases, respectively (P < 0.001), in the odds of an eggshell testing positive for Salmonella. The multilocus variable-number tandem-repeat analysis (MLVA) patterns of the S. Typhimurium strains isolated from flock A were distinct from those of flock B. S. Typhimurium strains detected from human food poisoning cases exhibited an MLVA pattern similar to those of the strains isolated from flocks A and B. PMID:24966362

  9. A novel antimicrobial peptide derived from fish goose type lysozyme disrupts the membrane of Salmonella enterica.

    PubMed

    Kumaresan, Venkatesh; Bhatt, Prasanth; Ganesh, Munuswamy-Ramanujam; Harikrishnan, Ramasamy; Arasu, MariadhasValan; Al-Dhabi, Naif Abdullah; Pasupuleti, Mukesh; Marimuthu, Kasi; Arockiaraj, Jesu

    2015-12-01

    In aquaculture, accumulation of antibiotics resulted in development of resistance among bacterial pathogens. Consequently, it became mandatory to find alternative to synthetic antibiotics. Antimicrobial peptides (AMPs) which are described as evolutionary ancient weapons have been considered as promising alternates in recent years. In this study, a novel antimicrobial peptide had been derived from goose type lysozyme (LyzG) which was identified from the cDNA library of freshwater fish Channa striatus (Cs). The identified lysozyme cDNA contains 585 nucleotides which encodes a protein of 194 amino acids. CsLyzG was closely related to Siniperca chuatsi with 92.8% homology. The depicted protein sequence contained a GEWL domain with conserved GLMQ motif, 7 active residues and 2 catalytic residues. Gene expression analysis revealed that CsLyzG was distributed in major immune organs with highest expression in head kidney. Results of temporal expression analysis after bacterial (Aeromonas hydrophila) and fungal (Aphanomyces invadans) challenges indicated a stimulant-dependent expression pattern of CsLyzG. Two antimicrobial peptides IK12 and TS10 were identified from CsLyzG and synthesized. Antibiogram showed that IK12 was active against Salmonella enterica, a major multi-drug resistant (MDR) bacterial pathogen which produces beta lactamase. The IK12 induced loss of cell viability in the bacterial pathogen. Flow cytometry assay revealed that IK12 disrupt the membrane of S. enterica which is confirmed by scanning electron microscope (SEM) analysis that reveals blebs around the bacterial cell membrane. Conclusively, CsLyzG is a potential innate immune component and the identified antimicrobial peptide has great caliber to be used as an ecofriendly antibacterial substance in aquaculture. PMID:26477736

  10. Ethanolamine Utilization Contributes to Proliferation of Salmonella enterica Serovar Typhimurium in Food and in Nematodes▿

    PubMed Central

    Srikumar, Shabarinath; Fuchs, Thilo M.

    2011-01-01

    Only three pathogenic bacterial species, Salmonella enterica, Clostridium perfringens, and Listeria monocytogenes, are able to utilize both ethanolamine and 1,2-propanediol as a sole carbon source. Degradation of these substrates, abundant in food and the gut, depends on cobalamin, which is synthesized de novo only under anaerobic conditions. Although the eut, pdu, and cob-cbi gene clusters comprise 40 kb, the conditions under which they confer a selection advantage on these food-borne pathogens remain largely unknown. Here we used the luciferase reporter system to determine the response of the Salmonella enterica serovar Typhimurium promoters PeutS, PpocR, PpduF, and PpduA to a set of carbon sources, to egg yolk, to whole milk, and to milk protein or fat fractions. Depending on the supplements, specific inductions up to 3 orders of magnitude were observed for PeutS and PpduA, which drive the expression of most eut and pdu genes. To correlate these significant expression data with growth properties, nonpolar deletions of pocR, regulating the pdu and cob-cbi genes, and of eutR, involved in eut gene activation, were constructed in S. Typhimurium strain 14028. During exponential growth of the mutants 14028ΔpocR and 14028ΔeutR, 2- to 3-fold-reduced proliferation in milk and egg yolk was observed. Using the Caenorhabditis elegans infection model, we could also demonstrate that the proliferation of S. Typhimurium in the nematode is supported by an active ethanolamine degradation pathway. Taking these findings together, this study quantifies the differential expression of eut and pdu genes under distinct conditions and provides experimental evidence that the ethanolamine utilization pathway allows salmonellae to occupy specific metabolic niches within food environments and within their host organisms. PMID:21037291

  11. Response of Medicago truncatula Seedlings to Colonization by Salmonella enterica and Escherichia coli O157:H7

    PubMed Central

    Jayaraman, Dhileepkumar; Valdés-López, Oswaldo; Kaspar, Charles W.; Ané, Jean-Michel

    2014-01-01

    Disease outbreaks due to the consumption of legume seedlings contaminated with human enteric bacterial pathogens like Escherichia coli O157:H7 and Salmonella enterica are reported every year. Besides contaminations occurring during food processing, pathogens present on the surface or interior of plant tissues are also responsible for such outbreaks. In the present study, surface and internal colonization of Medicago truncatula, a close relative of alfalfa, by Salmonella enterica and Escherichia coli O157:H7 were observed even with inoculum levels as low as two bacteria per plant. Furthermore, expression analyses revealed that approximately 30% of Medicago truncatula genes were commonly regulated in response to both of these enteric pathogens. This study highlights that very low inoculum doses trigger responses from the host plant and that both of these human enteric pathogens may in part use similar mechanisms to colonize legume seedlings. PMID:24551073

  12. Rapid Emergence and Clonal Dissemination of CTX-M-15-Producing Salmonella enterica Serotype Virchow, South Korea.

    PubMed

    Kim, Jin Seok; Yun, Young-Sun; Kim, Soo Jin; Jeon, Se-Eun; Lee, Deog-yong; Chung, Gyung Tae; Yoo, Cheon-Kwon; Kim, Junyoung

    2016-01-01

    The prevalence of cefotaxime-resistant Salmonella enterica serotype Virchow has dramatically increased in South Korea since the first isolation in 2011. Of 68 isolates collected over 10 years, 28 cefotaxime-resistant isolates harbored the bla(CTX-M-15) extended-spectrum β-lactamase gene and were closely related genetically, demonstrating the clonal dissemination of CTX-M-15-producing Salmonella Virchow in South Korea. PMID:26674083

  13. Salmonella enterica Serovar Typhimurium ompS1 and ompS2 Mutants Are Attenuated for Virulence in Mice

    PubMed Central

    Rodríguez-Morales, Olivia; Fernández-Mora, Marcos; Hernández-Lucas, Ismael; Vázquez, Alejandra; Puente, José Luis; Calva, Edmundo

    2006-01-01

    Salmonella enterica serovar Typhimurium mutants with mutations in the ompS1 and ompS2 genes, which code for quiescent porins, were nevertheless highly attenuated for virulence in a mouse model, indicating a role in pathogenesis. Similarly, a strain with a mutation in the gene coding for LeuO, a positive regulator of ompS2, was also attenuated. PMID:16428792

  14. Flagellin Is Required for Host Cell Invasion and Normal Salmonella Pathogenicity Island 1 Expression by Salmonella enterica Serovar Paratyphi A

    PubMed Central

    Elhadad, Dana; Desai, Prerak; Rahav, Galia; McClelland, Michael

    2015-01-01

    Salmonella enterica serovar Paratyphi A is a human-specific serovar that, together with Salmonella enterica serovar Typhi and Salmonella enterica serovar Sendai, causes enteric fever. Unlike the nontyphoidal Salmonella enterica serovar Typhimurium, the genomes of S. Typhi and S. Paratyphi A are characterized by inactivation of multiple genes, including in the flagellum-chemotaxis pathway. Here, we explored the motility phenotype of S. Paratyphi A and the role of flagellin in key virulence-associated phenotypes. Motility studies established that the human-adapted typhoidal S. Typhi, S. Paratyphi A, and S. Sendai are all noticeably less motile than S. Typhimurium, and comparative transcriptome sequencing (RNA-Seq) showed that in S. Paratyphi A, the entire motility-chemotaxis regulon is expressed at significantly lowers levels than in S. Typhimurium. Nevertheless, S. Paratyphi A, like S. Typhimurium, requires a functional flagellum for epithelial cell invasion and macrophage uptake, probably in a motility-independent mechanism. In contrast, flagella were found to be dispensable for host cell adhesion. Moreover, we demonstrate that in S. Paratyphi A, but not in S. Typhimurium, the lack of flagellin results in increased transcription of the flagellar and the Salmonella pathogenicity island 1 (SPI-1) regulons in a FliZ-dependent manner and in oversecretion of SPI-1 effectors via type three secretion system 1. Collectively, these results suggest a novel regulatory linkage between flagellin and SPI-1 in S. Paratyphi A that does not occur in S. Typhimurium and demonstrate curious distinctions in motility and the expression of the flagellum-chemotaxis regulon between these clinically relevant pathogens. PMID:26056383

  15. Flagellin Is Required for Host Cell Invasion and Normal Salmonella Pathogenicity Island 1 Expression by Salmonella enterica Serovar Paratyphi A.

    PubMed

    Elhadad, Dana; Desai, Prerak; Rahav, Galia; McClelland, Michael; Gal-Mor, Ohad

    2015-09-01

    Salmonella enterica serovar Paratyphi A is a human-specific serovar that, together with Salmonella enterica serovar Typhi and Salmonella enterica serovar Sendai, causes enteric fever. Unlike the nontyphoidal Salmonella enterica serovar Typhimurium, the genomes of S. Typhi and S. Paratyphi A are characterized by inactivation of multiple genes, including in the flagellum-chemotaxis pathway. Here, we explored the motility phenotype of S. Paratyphi A and the role of flagellin in key virulence-associated phenotypes. Motility studies established that the human-adapted typhoidal S. Typhi, S. Paratyphi A, and S. Sendai are all noticeably less motile than S. Typhimurium, and comparative transcriptome sequencing (RNA-Seq) showed that in S. Paratyphi A, the entire motility-chemotaxis regulon is expressed at significantly lowers levels than in S. Typhimurium. Nevertheless, S. Paratyphi A, like S. Typhimurium, requires a functional flagellum for epithelial cell invasion and macrophage uptake, probably in a motility-independent mechanism. In contrast, flagella were found to be dispensable for host cell adhesion. Moreover, we demonstrate that in S. Paratyphi A, but not in S. Typhimurium, the lack of flagellin results in increased transcription of the flagellar and the Salmonella pathogenicity island 1 (SPI-1) regulons in a FliZ-dependent manner and in oversecretion of SPI-1 effectors via type three secretion system 1. Collectively, these results suggest a novel regulatory linkage between flagellin and SPI-1 in S. Paratyphi A that does not occur in S. Typhimurium and demonstrate curious distinctions in motility and the expression of the flagellum-chemotaxis regulon between these clinically relevant pathogens. PMID:26056383

  16. Fate of Salmonella enterica in a mixed ingredient salad containing lettuce, cheddar cheese, and cooked chicken meat.

    PubMed

    Bovo, Federica; De Cesare, Alessandra; Manfreda, Gerardo; Bach, Susan; Delaquis, Pascal

    2015-03-01

    Food service and retail sectors offer consumers a variety of mixed ingredient salads that contain fresh-cut vegetables and other ingredients such as fruits, nuts, cereals, dairy products, cooked seafood, cooked meat, cured meats, or dairy products obtained from external suppliers. Little is known about the behavior of enteric bacterial pathogens in mixed ingredient salads. A model system was developed to examine the fate of Salmonella enterica (inoculum consisting of S. enterica serovars Agona, Typhimurium, Enteritidis, Brandenberg, and Kentucky) on the surface of romaine lettuce tissues incubated alone and in direct contact with Cheddar cheese or cooked chicken. S. enterica survived but did not grow on lettuce tissues incubated alone or in contact with Cheddar cheese for 6 days at either 6 or 14°C. In contrast, populations increased from 2.01 ± 0.22 to 9.26 ± 0.22 CFU/cm(2) when lettuce washed in water was incubated in contact with cooked chicken at 14°C. Populations on lettuce leaves were reduced to 1.28 ± 0.14 CFU/cm(2) by washing with a chlorine solution (70 ppm of free chlorine) but increased to 8.45 ± 0.22 CFU/cm(2) after 6 days at 14°C. Experimentation with a commercial product in which one third of the fresh-cut romaine lettuce was replaced with inoculated lettuce revealed that S. enterica populations increased by 4 log CFU/g during storage for 3 days at 14°C. These findings indicate that rapid growth of bacterial enteric pathogens may occur in mixed ingredient salads; therefore, strict temperature control during the manufacture, distribution, handling, and storage of these products is critical. PMID:25719871

  17. Whole-Genome Sequence of Salmonella enterica Serovar Enteritidis Phage Type 4, Isolated from a Brazilian Poultry Farm

    PubMed Central

    Nascimento, Leandro Costa; Tirabassi, Adriane Holtz; Rodrigues, Dália Prazeres; Pereira, Gonçalo Amarante Guimarães; Brocchi, Marcelo

    2016-01-01

    The draft genome of Salmonella enterica serovar Enteritidis phage type 4 (PT4) strain IOC4647/2004, isolated from a poultry farm in São Paulo state, was obtained with high-throughput Illumina sequencing platform, generating 4,173,826 paired-end reads with 251 bp. The assembly of 4,804,382 bp in 27 scaffolds shows strong similarity to other S. Enteritidis strains. PMID:27174265

  18. Emergence and properties of fluoroquinolone resistant Salmonella enterica serovar Typhi strains isolated from Nepal in 2002 and 2003.

    PubMed

    Nobthai, Panida; Serichantalergs, Oralak; Wongstitwilairoong, Boonchai; Srijan, Apichai; Bodhidatta, Ladaporn; Malla, Sarala; Mason, Carl J

    2010-11-01

    A total of 171 Salmonella enterica serovar Typhi strains isolated from Nepal, mostly from patients with typhoid fever in 2002-2003, were tested for antimicrobial susceptibility by disk diffusion assay. Selected S. enterica serovar Typhi isolates were tested for MICs by E-test for ceftriaxone, ciprofloxacin and ofloxacin. Mutations of DNA gyrase gyrA and gyrB and topoisomerase IV parC and parE were identified by sequencing of PCR amplicons. By disk diffusion assay, 75/171 S. enterica serovar Typhi isolates were resistant to nalidixic acid, ampicillin, choramphenicol, streptomycin, tetracycline, sulfisoxazole, and trimethroprim/sulfamethoxazoles. Multiple drug resistance to the 7 antimicrobials was most predominant among S. enterica serovar Typhi isolates in this study. Resistance to nalidixic acid was detected in 76/111 and 56/60 of total isolates collected in 2002 and 2003, respectively. Nalidixic acid-resistant isolates in 2002 and 2003 showed MIC range for ciprofloxacin of 0.125-0.250 mg/l. Nalidixic acid-resistant isolates contained point mutations in gyrA and parC but not gyrB and parE. The gyrA mutation of nalidixic acid-resistant isolates obtained in 2002 and 2003 had amino acid substitution at position 83 of Serine-->Tyrosine and Serine-->Phenylalanine, respectively. Two different mutations of gyrA were detected among nalidixic acid-resistant isolates. Thus it is necessary to monitor mutation in DNA topoisomerase associated with increases in quinolones resistance. PMID:21329318

  19. Infection of Murine Macrophages by Salmonella enterica Serovar Heidelberg Blocks Murine Norovirus Infectivity and Virus-induced Apoptosis.

    PubMed

    Agnihothram, Sudhakar S; Basco, Maria D S; Mullis, Lisa; Foley, Steven L; Hart, Mark E; Sung, Kidon; Azevedo, Marli P

    2015-01-01

    Gastroenteritis caused by bacterial and viral pathogens constitutes a major public health threat in the United States accounting for 35% of hospitalizations. In particular, Salmonella enterica and noroviruses cause the majority of gastroenteritis infections, with emergence of sporadic outbreaks and incidence of increased infections. Although mechanisms underlying infections by these pathogens have been individually studied, little is known about the mechanisms regulating co-infection by these pathogens. In this study, we utilized RAW 264.7 murine macrophage cells to investigate the mechanisms governing co-infection with S. enterica serovar Heidelberg and murine norovirus (MNV). We demonstrate that infection of RAW 264.7 cells with S. enterica reduces the replication of MNV, in part by blocking virus entry early in the virus life cycle, and inducing antiviral cytokines later in the infection cycle. In particular, bacterial infection prior to, or during MNV infection affected virus entry, whereas MNV entry remained unaltered when the virus infection preceded bacterial invasion. This block in virus entry resulted in reduced virus replication, with the highest impact on replication observed during conditions of co-infection. In contrast, bacterial replication showed a threefold increase in MNV-infected cells, despite the presence of antibiotic in the medium. Most importantly, we present evidence that the infection of MNV-infected macrophages by S. enterica blocked MNV-induced apoptosis, despite allowing efficient virus replication. This apoptosis blockade was evidenced by reduction in DNA fragmentation and absence of poly-ADP ribose polymerase (PARP), caspase 3 and caspase 9 cleavage events. Our study suggests a novel mechanism of pathogenesis whereby initial co-infection with these pathogens could result in prolonged infection by either of these pathogens or both together. PMID:26658916

  20. Prevalence and characterization of multi-drug resistant Salmonella Enterica serovar Gallinarum biovar Pullorum and Gallinarum from chicken

    PubMed Central

    Parvej, Md. Shafiullah; Nazir, K. H. M. Nazmul Hussain; Rahman, M. Bahanur; Jahan, Mueena; Khan, Mohammad Ferdousur Rahman; Rahman, Marzia

    2016-01-01

    Aim: Salmonella is an important zoonotic pathogen responsible for animal and human diseases. The aim of the present study was to determine the prevalence and stereotyping of Salmonella isolates isolated from apparently healthy poultry. Furthermore, the clonal relatedness among the isolated Salmonella serovars was assessed. Materials and Methods: A total of 150 cloacal swab samples from apparently healthy chickens were collected, and were subjected for the isolation and identification of associated Salmonella organisms. The isolated colonies were identified and characterized on the basis of morphology, cultural characters, biochemical tests, slide agglutination test, polymerase chain reaction, and pulsed-field gel electrophoresis (PFGE). Antibiotic sensitivity patterns were also investigated using commonly used antibiotics. Results: Of the 150 samples, 11 (7.33%) produced characteristics pink colony with black center on XLD agar medium, and all were culturally and biochemically confirmed to be Salmonella. All possessed serovar-specific gene SpeF and reacted uniformly with group D antisera, suggesting that all of the isolates were Salmonella Enterica serovar Gallinarum, biovar Pullorum and/or Gallinarum. Antimicrobial susceptibility testing revealed that 54.54% of the isolated Salmonella Enterica serovars were highly sensitive to ciprofloxacin, whereas the 81.81% isolates were resistant to amoxycillin, doxycycline, kanamycin, gentamycin, and tetracycline. Pulsed-field gel electrophoresis of the XbaI-digested genomic DNA exhibited identical banding patterns, suggesting that the multidrug resistant Salmonella Enterica serovars occurring in commercial layers are highly clonal in Bangladesh. Conclusion: The present study was conducted to find out the prevalence of poultry Salmonella in layer chicken and to find out the clonal relationship among them. The data in this study suggest the prevalence of Salmonella Enterica, which is multidrug resistant and highly clonal for

  1. Complete Genome Sequences of Salmonella enterica Serovars Anatum and Anatum var. 15+, Isolated from Retail Ground Turkey

    PubMed Central

    Marasini, Daya; Abo-Shama, Usama H.

    2016-01-01

    The complete genome sequences of two isolates of Salmonella enterica serovars Anatum and Anatum var. 15+ revealed the presence of two plasmids of 112 kb and 3 kb in size in each. The chromosome of Salmonella Anatum (4.83 Mb) was slightly smaller than that of Salmonella Anatum var. 15+ (4.88 Mb). PMID:26798111

  2. A eukaryotic-like 3′ untranslated region in Salmonella enterica hilD mRNA

    PubMed Central

    López-Garrido, Javier; Puerta-Fernández, Elena; Casadesús, Josep

    2014-01-01

    Long 3′ untranslated regions (3′UTRs) are common in eukaryotic mRNAs. In contrast, long 3′UTRs are rare in bacteria, and have not been characterized in detail. We describe a 3′UTR of 310 nucleotides in hilD mRNA, a transcript that encodes a transcriptional activator of Salmonella enterica pathogenicity island 1 (SPI-1). Deletion of the hilD 3′UTR increases the hilD mRNA level, suggesting that the hilD 3′UTR may play a role in hilD mRNA turnover. Cloning of the hilD 3′UTR downstream of the green fluorescent protein (gfp) gene decreases green fluorescent protein (GFP) activity in both Escherichia coli and S. enterica, indicating that the hilD 3′UTR can act as an independent module. S. enterica mutants lacking either ribonuclease E or polynucleotide phosphorylase contain similar amounts of hilD and hilD Δ3′UTR mRNAs, suggesting that the hilD 3′UTR is a target for hilD mRNA degradation by the degradosome. The hilD 3′UTR is also necessary for modulation of hilD and SPI-1 expression by the RNA chaperone Hfq. Overexpression of SPI-1 in the absence of the hilD 3′UTR retards Salmonella growth and causes uncontrolled invasion of epithelial cells. Based on these observations, we propose that the S. enterica hilD 3′UTR is a cis-acting element that contributes to cellular homeostasis by promoting hilD mRNA turnover. PMID:24682814

  3. Infection of Murine Macrophages by Salmonella enterica Serovar Heidelberg Blocks Murine Norovirus Infectivity and Virus-induced Apoptosis

    PubMed Central

    Agnihothram, Sudhakar S.; Basco, Maria D. S.; Mullis, Lisa; Foley, Steven L.; Hart, Mark E.; Sung, Kidon; Azevedo, Marli P.

    2015-01-01

    Gastroenteritis caused by bacterial and viral pathogens constitutes a major public health threat in the United States accounting for 35% of hospitalizations. In particular, Salmonella enterica and noroviruses cause the majority of gastroenteritis infections, with emergence of sporadic outbreaks and incidence of increased infections. Although mechanisms underlying infections by these pathogens have been individually studied, little is known about the mechanisms regulating co-infection by these pathogens. In this study, we utilized RAW 264.7 murine macrophage cells to investigate the mechanisms governing co-infection with S. enterica serovar Heidelberg and murine norovirus (MNV). We demonstrate that infection of RAW 264.7 cells with S. enterica reduces the replication of MNV, in part by blocking virus entry early in the virus life cycle, and inducing antiviral cytokines later in the infection cycle. In particular, bacterial infection prior to, or during MNV infection affected virus entry, whereas MNV entry remained unaltered when the virus infection preceded bacterial invasion. This block in virus entry resulted in reduced virus replication, with the highest impact on replication observed during conditions of co-infection. In contrast, bacterial replication showed a threefold increase in MNV-infected cells, despite the presence of antibiotic in the medium. Most importantly, we present evidence that the infection of MNV-infected macrophages by S. enterica blocked MNV-induced apoptosis, despite allowing efficient virus replication. This apoptosis blockade was evidenced by reduction in DNA fragmentation and absence of poly-ADP ribose polymerase (PARP), caspase 3 and caspase 9 cleavage events. Our study suggests a novel mechanism of pathogenesis whereby initial co-infection with these pathogens could result in prolonged infection by either of these pathogens or both together. PMID:26658916

  4. Pectin and Xyloglucan Influence the Attachment of Salmonella enterica and Listeria monocytogenes to Bacterial Cellulose-Derived Plant Cell Wall Models

    PubMed Central

    Tan, Michelle S. F.; Rahman, Sadequr

    2015-01-01

    Minimally processed fresh produce has been implicated as a major source of foodborne microbial pathogens globally. These pathogens must attach to the produce in order to be transmitted. Cut surfaces of produce that expose cell walls are particularly vulnerable. Little is known about the roles that different structural components (cellulose, pectin, and xyloglucan) of plant cell walls play in the attachment of foodborne bacterial pathogens. Using bacterial cellulose-derived plant cell wall models, we showed that the presence of pectin alone or xyloglucan alone affected the attachment of three Salmonella enterica strains (Salmonella enterica subsp. enterica serovar Enteritidis ATCC 13076, Salmonella enterica subsp. enterica serovar Typhimurium ATCC 14028, and Salmonella enterica subsp. indica M4) and Listeria monocytogenes ATCC 7644. In addition, we showed that this effect was modulated in the presence of both polysaccharides. Assays using pairwise combinations of S. Typhimurium ATCC 14028 and L. monocytogenes ATCC 7644 showed that bacterial attachment to all plant cell wall models was dependent on the characteristics of the individual bacterial strains and was not directly proportional to the initial concentration of the bacterial inoculum. This work showed that bacterial attachment was not determined directly by the plant cell wall model or bacterial physicochemical properties. We suggest that attachment of the Salmonella strains may be influenced by the effects of these polysaccharides on physical and structural properties of the plant cell wall model. Our findings improve the understanding of how Salmonella enterica and Listeria monocytogenes attach to plant cell walls, which may facilitate the development of better ways to prevent the attachment of these pathogens to such surfaces. PMID:26567310

  5. Novel Attenuated Salmonella enterica Serovar Choleraesuis Strains as Live Vaccine Candidates Generated by Signature-Tagged Mutagenesis

    PubMed Central

    Ku, Yu-We; McDonough, Sean P.; Palaniappan, Raghavan U. M.; Chang, Chao-Fu; Chang, Yung-Fu

    2005-01-01

    Salmonella enterica serovar Choleraesuis is a host-adapted pathogen that causes swine paratyphoid. Signature-tagged mutagenesis (STM) was used to understand the pathogenicity of S. enterica serovar Choleraesuis in its natural host and also to develop novel attenuated live vaccine candidates against this disease. A library of 960 signature-tagged mutants of S. enterica serovar Choleraesuis was constructed and screened for attenuation in pigs. Thirty-three mutants were identified by the STM screening, and these mutants were further screened for attenuation by in vivo and in vitro competitive growth. Of these, 20 mutants targeting the outer membrane, type III secretion, transporter, lipopolysaccharide biosynthesis, and other unknown proteins were confirmed for attenuation. Five highly attenuated mutants (SC2D2 [ssaV], SC4A9 [gifsy-1], SC6F9 [dgoT], SC12B12 [ssaJ], and SC10B1[spiA]) were selected and evaluated for safety and protective efficacy in pigs by comparison with a commercially available vaccine strain. STM-attenuated live vaccine strains SC4A9 (gifsy-1) and SC2D2 (ssaV) were superior to commercially available live vaccine because they provided both safety and a protective immune response against challenge in pigs. PMID:16299315

  6. Salmonella enterica Serovar Szentes, a Rare Serotype Causing a 9-Month Outbreak in 2013 and 2014 in Switzerland.

    PubMed

    Nüesch-Inderbinen, Magdalena; Cernela, Nicole; Althaus, Denise; Hächler, Herbert; Stephan, Roger

    2015-11-01

    During the summer of 2013, an increase of Salmonella enterica ssp. enterica serovar Szentes isolates from human clinical cases was registered by the Swiss National Centre for Enteropathogenic Bacteria and Listeria. In the course of the ensuing 9 months, 18 isolates originating from 13 patients and from one food sample were collected. Of the 13 human cases, 10 (77%) were female. The patients' ages ranged from 27 to 83 years (median age 49 years). Pulsed-field gel electrophoresis (PFGE) performed with XbaI, and multilocus sequence typing (MLST) were used to type the strains. PFGE as well as MLST showed the strains as indistinguishable. The PFGE pattern and MLST sequence type (ST427) were identical to those of Salmonella enterica serovar Szentes isolated in previous years (2002-2013) from sporadic cases in Switzerland and Germany. The increased isolation frequency continued for 6 months after the detection of Salmonella Szentes in sprouts. No common food exposure could be established. Due to lack of information on the potential food source, further investigations were not possible. The outbreak of this unusual serotype was detected because of its temporal clustering. PMID:26287690

  7. The distribution of Salmonella enterica serovars and subtypes in surface water from five agricultural regions across Canada.

    PubMed

    Jokinen, C C; Koot, J; Cole, L; Desruisseau, A; Edge, T A; Khan, I U H; Koning, W; Lapen, D R; Pintar, K D M; Reid-Smith, R; Thomas, J L; Topp, E; Wang, L Y; Wilkes, G; Ziebell, K; van Bochove, E; Gannon, V P J

    2015-06-01

    Serovar prevalence of the zoonotic pathogen, Salmonella enterica, was compared among 1624 surface water samples collected previously from five different Canadian agricultural watersheds over multiple years. Phagetyping, pulsed field gel electrophoresis (PFGE), and antimicrobial resistance subtyping assays were performed on serovars Enteritidis, Typhimurium, and Heidelberg. Serovars and subtypes from surface water were compared with those from animal feces, human sewage, and serovars reported to cause salmonellosis in Canadians. Sixty-five different serovars were identified in surface water; only 32% of these were isolated from multiple watersheds. Eleven of the 13 serovars most commonly reported to cause salmonellosis in Canadians were identified in surface water; isolates of these serovars constituted >40% of the total isolates. Common phagetypes and PFGE subtypes of serovars associated with illness in humans such as S. Enteritidis and S. Typhimurium were also isolated from surface water and animal feces. Antimicrobial resistance was generally low, but was highest among S. Typhimurium. Monitoring of these rivers helps to identify vulnerable areas of a watershed and, despite a relatively low prevalence of S. enterica overall, serovars observed in surface water are an indication of the levels of specific S. enterica serovars present in humans and animals. PMID:25799976

  8. Effects of indole on drug resistance and virulence of Salmonella enterica serovar Typhimurium revealed by genome-wide analyses

    PubMed Central

    2012-01-01

    Background Many Gram-positive and Gram-negative bacteria produce large quantities of indole as an intercellular signal in microbial communities. Indole demonstrated to affect gene expression in Escherichia coli as an intra-species signaling molecule. In contrast to E. coli, Salmonella does not produce indole because it does not harbor tnaA, which encodes the enzyme responsible for tryptophan metabolism. Our previous study demonstrated that E. coli-conditioned medium and indole induce expression of the AcrAB multidrug efflux pump in Salmonella enterica serovar Typhimurium for inter-species communication; however, the global effect of indole on genes in Salmonella remains unknown. Results To understand the complete picture of genes regulated by indole, we performed DNA microarray analysis of genes in the S. enterica serovar Typhimurium strain ATCC 14028s affected by indole. Predicted Salmonella phenotypes affected by indole based on the microarray data were also examined in this study. Indole induced expression of genes related to efflux-mediated multidrug resistance, including ramA and acrAB, and repressed those related to host cell invasion encoded in the Salmonella pathogenicity island 1, and flagella production. Reduction of invasive activity and motility of Salmonella by indole was also observed phenotypically. Conclusion Our results suggest that indole is an important signaling molecule for inter-species communication to control drug resistance and virulence of S. enterica. PMID:22632036

  9. Involvement of a Salmonella Genomic Island 1 Gene in the Rumen Protozoan-Mediated Enhancement of Invasion for Multiple-Antibiotic-Resistant Salmonella enterica Serovar Typhimurium▿

    PubMed Central

    Carlson, Steve A.; Sharma, Vijay K.; McCuddin, Zoe P.; Rasmussen, Mark A.; Franklin, Sharon K.

    2007-01-01

    Multiple-antibiotic-resistant Salmonella enterica serotype Typhimurium is a food-borne pathogen that may be more virulent than related strains lacking the multiresistance phenotype. Salmonella enterica serotype Typhimurium phage type DT104 is the most prevalent of these multiresistant/hypervirulent strains. Multiresistance in DT104 is conferred by an integron structure, designated Salmonella genomic island 1 (SGI1), while we recently demonstrated DT104 hyperinvasion mediated by rumen protozoa (RPz) that are normal flora of cattle. Hyperinvasion was also observed in other Salmonella strains, i.e., other S. enterica serovar Typhimurium phage types and other S. enterica serovars, like S. enterica serovar Infantis, possessing SGI1, while DT104 strains lacking SGI1 were not hyperinvasive. Herein we attempted to identify SGI1 genes involved in the RPz-mediated hyperinvasion of Salmonella strains bearing SGI1. Transposon mutagenesis, coupled with a novel reporter system, revealed the involvement of an SGI1 gene previously designated SO13. Disruption of SO13 expression led to an abrogation of hyperinvasion as assessed by tissue culture invasion assays and by bovine challenge experiments. However, hyperinvasion was not observed in non-SGI1-bearing strains of Salmonella engineered to express SO13. That is, SO13 and another SGI1 gene(s) may coordinately upregulate invasion in DT104 exposed to RPz. PMID:17145942

  10. Detection and Molecular Characterization of Salmonella enterica Serovar Eppendorf Circulating in Chicken Farms in Tunisia.

    PubMed

    Ben Salem, R; Abbassi, M S; García, V; García-Fierro, R; Njoud, C; Messadi, L; Rodicio, M R

    2016-06-01

    Salmonella enterica subsp. enterica serovar Eppendorf, with antigenic formula 1,4,12,[27]:d:1,5, is an infrequent serovar. However, 14% (20 of 142) of the isolates recovered during June-July 2012 in chicken farms in Tunisia belonged to S. Eppendorf. These isolates were analysed for resistance and virulence profiles. None of them were susceptible to all antimicrobials tested, while 70%, 60%, 50%, 50%, 20% and 5% were resistant to sulphonamides (sul1, sul2 and sul3), streptomycin (aadA1-like), trimethoprim (dfrA1-like), nalidixic acid (GyrA Asp87 →Asn and not identified), gentamicin (not identified) and ampicillin (blaTEM -1-like). About 30% of the isolates showed decreased susceptibility to ciprofloxacin and carried the qnrB gene; 65% of the isolates were multidrug resistant and contained class 1 integrons with sul1 or sul3 in the 3' conserved segment. The orgA, ssaQ, mgtC, siiD and sopB virulence genes located on SPI1 to SPI5 and the fimbrial bcfC gene were present in all isolates; the sopE1 and sodC1 carried by prophages were variably detected; however, the prophage gipA gene and the spvC gene of serovar-specific virulence plasmids were absent. Altogether, ten resistance and three virulence profiles were identified. Typing of the isolates with XbaI- and BlnI-PFGE supports a close relationship, although they appear to be evolving under selective pressure probably caused by antimicrobial use in chicken husbandry. As far as we know, this is the first study investigating the molecular bases of antimicrobial drug resistance, the virulence gene content and the PFGE profiles of S. Eppendorf. The epidemiological surveillance of this serovar would be necessary to evaluate its possible impact on human health, particularly in Tunisia and other African countries where it was already reported. PMID:26537844

  11. Characterization of FimH adhesins expressed by Salmonella enterica serovar Gallinarum biovars Gallinarum and Pullorum: reconstitution of mannose-binding properties by single amino acid substitution.

    PubMed

    Kisiela, Dagmara; Sapeta, Anna; Kuczkowski, Maciej; Stefaniak, Tadeusz; Wieliczko, Alina; Ugorski, Maciej

    2005-09-01

    Recombinant FimH adhesins of type 1 fimbriae from Salmonella enterica serovar Gallinarum biovars Gallinarum and Pullorum, in contrast to those of Salmonella enterica serovar Typhimurium, did not bind to high-mannose oligosaccharides or to human colon carcinoma HT-29 cells. However, mutated FimH proteins from biovar Gallinarum and biovar Pullorum, in which the isoleucine at position 78 was replaced by the threonine found in S. enterica serovar Typhimurium, bound well to glycoproteins carrying high-mannose oligosaccharides and colon carcinoma cells. The loss of sugar-binding properties by biovar Gallinarum and biovar Pullorum FimH adhesins, which are a part of the type 1 fimbriae, is most probably the result of a single T78I mutation, as was proven by site-directed mutagenesis of FimH proteins. PMID:16113346

  12. Type I interferon induces necroptosis in macrophages during infection with Salmonella enterica serovar Typhimurium

    PubMed Central

    Robinson, Nirmal; McComb, Scott; Mulligan, Rebecca; Dudani, Renu; Krishnan, Lakshmi; Sad, Subash

    2014-01-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is a virulent pathogen that induces rapid host death. Here we observed that host survival after infection with S. Typhimurium was enhanced in the absence of type I interferon signaling, with improved survival of mice deficient in the receptor for type I interferons (Ifnar1−/− mice) that was attributed to macrophages. Although there was no impairment in cytokine expression or inflammasome activation in Ifnar1−/− macrophages, they were highly resistant to S. Typhimurium–induced cell death. Specific inhibition of the kinase RIP1or knockdown of the gene encoding the kinase RIP3 prevented the death of wild-type macrophages, which indicated that necroptosis was a mechanism of cell death. Finally, RIP3-deficient macrophages, which cannot undergo necroptosis, had similarly less death and enhanced control of S. Typhimurium in vivo. Thus, we propose that S. Typhimurium induces the production of type I interferon, which drives necroptosis of macrophages and allows them to evade the immune response. PMID:22922364

  13. Genetic Diversity and Evolution of Salmonella enterica Serovar Enteritidis Strains with Different Phage Types

    PubMed Central

    Pettengill, James; Strain, Errol; Allard, Marc W.; Ahmed, Rafiq; Zhao, Shaohua; Brown, Eric W.

    2014-01-01

    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 United States. Emphasis was placed on the predominant phage types PT8, PT13a, and PT13 in North America. With >89,400 bp surveyed across 98 S. Enteritidis isolates representing 14 distinct phage types, 55 informative SNPs were discovered within 23 chromosomally anchored loci. To maximize the discriminatory and evolutionary partitioning of these highly homogeneous strains, sequences comprising informative SNPs were concatenated into a single combined data matrix and subjected to phylogenetic analysis. The resultant phylogeny allocated most S. Enteritidis isolates into two distinct clades (clades I and II) and four subclades. Synapomorphic (shared and derived) sets of SNPs capable of distinguishing individual clades/subclades were identified. However, individual phage types appeared to be evolutionarily disjunct when mapped to this phylogeny, suggesting that phage typing may not be valid for making phylogenetic inferences. Furthermore, the set of SNPs identified here represents useful genetic markers for strain differentiation of more clonal S. Enteritidis strains and provides core genotypic markers for future development of a SNP typing scheme with S. Enteritidis. PMID:24574287

  14. Efficiency of Conditionally Attenuated Salmonella enterica Serovar Typhimurium in Bacterium-Mediated Tumor Therapy

    PubMed Central

    Frahm, Michael; Kocijancic, Dino; Rohde, Manfred; Hensel, Michael; Curtiss, Roy; Erhardt, Marc; Weiss, Siegfried

    2015-01-01

    ABSTRACT Increasing numbers of cancer cases generate a great urge for new treatment options. Applying bacteria like Salmonella enterica serovar Typhimurium for cancer therapy represents an intensively explored option. These bacteria have been shown not only to colonize solid tumors but also to exhibit an intrinsic antitumor effect. In addition, they could serve as tumor-targeting vectors for therapeutic molecules. However, the pathogenic S. Typhimurium strains used for tumor therapy need to be attenuated for safe application. Here, lipopolysaccharide (LPS) deletion mutants (ΔrfaL, ΔrfaG, ΔrfaH, ΔrfaD, ΔrfaP, and ΔmsbB mutants) of Salmonella were investigated for efficiency in tumor therapy. Of such variants, the ΔrfaD and ΔrfaG deep rough mutants exhibited the best tumor specificity and lowest pathogenicity. However, the intrinsic antitumor effect was found to be weak. To overcome this limitation, conditional attenuation was tested by complementing the mutants with an inducible arabinose promoter. The chromosomal integration of the respective LPS biosynthesis genes into the araBAD locus exhibited the best balance of attenuation and therapeutic benefit. Thus, the present study establishes a basis for the development of an applicably cancer therapeutic bacterium. PMID:25873375

  15. Enhanced survival of Salmonella enterica in vesicles released by a soilborne Tetrahymena species.

    PubMed

    Brandl, M T; Rosenthal, B M; Haxo, A F; Berk, S G

    2005-03-01

    Nondestructive ingestion by soilborne protozoa may enhance the environmental resiliency of important bacterial pathogens and may model how such bacteria evade destruction in human macrophages. Here, the interaction of Salmonella enterica serovar Thompson with a soilborne Tetrahymena sp. isolate was examined using serovar Thompson cells labeled with the green fluorescent protein. The bacteria were mixed in solution with cells of Tetrahymena at several ratios. During incubation with serovar Thompson, Tetrahymena cells released a large number of vesicles containing green fluorescent serovar Thompson cells. In comparison, grazing on Listeria monocytogenes cells resulted in their digestion and thus the infrequent release of this pathogen in vesicles. The number of serovar Thompson cells per vesicle increased significantly as the initial ratio of serovar Thompson to Tetrahymena cells increased from 500:1 to 5,000:1. The density of serovar Thompson was as high as 50 cells per vesicle. Staining with propidium iodide revealed that a significantly higher proportion of serovar Thompson cells remained viable when enclosed in vesicles than when free in solution. Enhanced survival rates were observed in vesicles that were secreted by both starved (F = 28.3, P < 0.001) and unstarved (F = 14.09, P < 0.005) Tetrahymena cells. Sequestration in vesicles also provided greater protection from low concentrations of calcium hypochlorite. Thus, the release of this human pathogen from Tetrahymena cells in high-density clusters enclosed in a membrane may have important implications for public health. PMID:15746361

  16. Models of intestinal infection by Salmonella enterica: introduction of a new neonate mouse model

    PubMed Central

    Schulte, Marc; Hensel, Michael

    2016-01-01

    Salmonella enterica serovar Typhimurium is a foodborne pathogen causing inflammatory disease in the intestine following diarrhea and is responsible for thousands of deaths worldwide. Many in vitro investigations using cell culture models are available, but these do not represent the real natural environment present in the intestine of infected hosts. Several in vivo animal models have been used to study the host-pathogen interaction and to unravel the immune responses and cellular processes occurring during infection. An animal model for Salmonella-induced intestinal inflammation relies on the pretreatment of mice with streptomycin. This model is of great importance but still shows limitations to investigate the host-pathogen interaction in the small intestine in vivo. Here, we review the use of mouse models for Salmonella infections and focus on a new small animal model using 1-day-old neonate mice. The neonate model enables researchers to observe infection of both the small and large intestine, thereby offering perspectives for new experimental approaches, as well as to analyze the Salmonella-enterocyte interaction in the small intestine in vivo. PMID:27408697

  17. Molecular characteristics of Salmonella enterica Paratyphi A in Yunnan Province, southwest China.

    PubMed

    Gu, Wenpeng; Yang, Zushun; Chen, Yujuan; Yin, Jianwen; Yang, Jianbin; Li, Chaoqun; Zhou, Yongming; Yin, Jie; Xu, Wen; Zhao, Shiwen; Liang, Junrong; Wang, Xin; Jing, Huaiqi; Fu, Xiaoqing

    2015-03-01

    Previously, the prevalence of Salmonella enterica Paratyphi A in Yunnan was high; and recently Yunnan was the predominant endemic province in China. To identify the molecular epidemiology, antibiotic resistance profile and genotypic diversity of the S. Paratyphi A isolates from 1995 to 2013 in Yunnan, we performed the study. Antibiotic susceptibility tests, pulse-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to identify the characteristics of the bacterial isolates. The results showed from 1995 to 2013, 366 S. Paratyphi A were isolated: 295 isolates (80.6%) from Yuxi and 68 isolates (18.58%) from Honghe. All of the strains were resistant to nalidixic acid, and some were resistant to ampicillin and trimethoprim/sulfamethoxazole in different years. All the isolates were sensitive to cefotaxime and ciprofloxacin. Identical PFGE with two enzyme digestion patterns were found for 339 isolates. Some environmental isolates in different years were homologous with the strains isolated from food and patients. MLST showed 349 strains were ST85, only 17 isolates were ST129. S. Paratyphi A isolates from Yunnan showed a high similarity, and we found the pathogen isolated from patients, the environment and food had the close epidemiological relationship, forming a transmission circulation. These findings have important implications for paratyphoid-control strategies. PMID:25555526

  18. Requirement for cobalamin by Salmonella enterica serovars Typhimurium, Pullorum, Gallinarum and Enteritidis during infection in chickens

    PubMed Central

    Vaz, Jacqueline Boldrin; Penha Filho, Rafael Antonio Casarin; Junior, Angelo Berchieri; Lemos, Manoel Victor Franco

    2011-01-01

    Salmonella enterica serovar Typhimurium synthesizes cobalamin (vitamin B12) only during anaerobiosis. Two percent of the S. Typhimurium genome is devoted to the synthesis and uptake of vitamin B12 and to B12-dependent reactions. To understand the requirement for cobalamin synthesis better, we constructed mutants of Salmonella serovars Enteritidis and Pullorum that are double-defective in cobalamin biosynthesis (ΔcobSΔcbiA). We compared the virulence of these mutants to that of their respective wild type strains and found no impairment in their ability to cause disease in chickens. We then assessed B12 production in these mutants and their respective wild type strains, as well as in S. Typhimurium ΔcobSΔcbiA, Salmonella Gallinarum ΔcobSΔcbiA, and their respective wild type strains. None of the mutants was able to produce detectable B12. B12 was detectable in S. Enteritidis, S. Pullorum and S. Typhimurium wild type strains but not in S. Gallinarum. In conclusion, the production of vitamin B12in vitro differed across the tested Salmonella serotypes and the deletion of the cbiA and cobS genes resulted in different levels of alteration in the host parasite interaction according to Salmonella serotype tested. PMID:24031771

  19. Biochemical and molecular characterization of Salmonella enterica serovar berta, and comparison of methods for typing.

    PubMed Central

    Olsen, J. E.; Brown, D. J.; Baggesen, D. L.; Bisgaard, M.

    1992-01-01

    Strains of Salmonella enterica serovar berta (S. berta) from Denmark and seven other countries have been characterized with the aim of developing a rational typing strategy in connection with outbreak investigations. Biotyping divided the strains into H2S-positive (90%) and H2S-negative (10%) biovars. Six percent of the strains were resistant to one or more antimicrobial agents. Eighty-eight percent of the strains carried plasmids and 52 different plasmid profiles were recognized. Six of the common plasmid sizes in these profiles were shown by restriction enzyme analyses to contain more than one plasmid species. More than 90% of the strains had the same ribotype with the restriction enzymes Sma I and EcoR I and the same whole cell protein profile. Outer membrane protein profiles and isoenzyme profiles were identical in all S. berta analysed. Plasmid profiling in combination with restriction enzyme analysis of plasmids seemed to be the most rational typing strategy for S. berta. The results indicated that S. berta strains regardless of geographical source or host are possibly clonal in nature. Images Fig. 1 Fig. 2 Fig. 3 PMID:1582467

  20. Direct ROS scavenging activity of CueP from Salmonella enterica serovar Typhimurium.

    PubMed

    Yoon, Bo-Young; Yeom, Ji-Hyun; Kim, Jin-Sik; Um, Si-Hyeon; Jo, Inseong; Lee, Kangseok; Kim, Yong-Hak; Ha, Nam-Chul

    2014-02-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is an intracellular pathogen that has evolved to survive in the phagosome of macrophages. The periplasmic copper-binding protein CueP was initially known to confer copper resistance to S. Typhimurium. Crystal structure and biochemical studies on CueP revealed a putative copper binding site surrounded by the conserved cysteine and histidine residues. A recent study reported that CueP supplies copper ions to periplasmic Cu, Zn-superoxide dismutase (SodCII) at a low copper concentration and thus enables the sustained SodCII activity in the periplasm. In this study, we investigated the role of CueP in copper resistance at a high copper concentration. We observed that the survival of a cueP-deleted strain of Salmonella in macrophage phagosome was significantly reduced. Subsequent biochemical experiments revealed that CueP specifically mediates the reduction of copper ion using electrons released during the formation of the disulfide bond. We observed that the copper ion-mediated Fenton reaction in the presence of hydrogen peroxide was blocked by CueP. This study provides insight into how CueP confers copper resistance to S. Typhimurium in copper-rich environments such as the phagosome of macrophages. PMID:24598994

  1. Multiple antimicrobial resistant Salmonella enterica serovar Paratyphi B variant Java in cattle: a case report.

    PubMed

    Evans, S J; Davies, R H; Binns, S H; Liebana, E; Jones, T W H; Millar, M F; Threlfall, E J; Ward, L R; Hopkins, K L; Mackay, P H S; Gayford, P J R

    2005-03-12

    An epidemiological investigation of a calf rearing premises and a closely associated dairy herd was carried out after the isolation of Salmonella enterica serovar Paratyphi B variant Java phage type 3b variant 2 from clinically diseased calves on the premises. The isolate was resistant to ampicillin, chloramphenicol, streptomycin, sulphonamides, tetracyclines, trimethoprim and cefoperazone. The organism was widespread on the calf unit and was also recovered from the dairy premises, mainly from groups of weaned calves. The investigation was extended to 10 epidemiologically linked farms but no S Java was isolated from any of the 40 to 60 samples collected from each premises. Molecular studies showed that the S Java isolates were genetically most similar to isolates from cases of human disease associated with ornamental fish tanks or feed. Long PCR and resistance gene profiling identified a resistance island which was indistinguishable from the human 'fish tank' strain of S Java and animal and human epidemic strains of S Typhimurium DT104. The isolates were clearly distinguished from multi-resistant S Java strains commonly associated with continental poultry. This is the first report of S Java with this resistance pattern in Great Britain. PMID:15789647

  2. Multiple antibiotic resistance (mar) locus in Salmonella enterica serovar typhimurium DT104.

    PubMed

    Randall, L P; Woodward, M J

    2001-03-01

    In order to understand the role of the mar locus in Salmonella with regard to multiple antibiotic resistance, cyclohexane resistance, and outer membrane protein F (OmpF) regulation, a marA::gfp reporter mutant was constructed in an antibiotic-sensitive Salmonella enterica serovar Typhimurium DT104 background. Salicylate induced marA, whereas a number of antibiotics, disinfectants, and various growth conditions did not. Increased antibiotic resistance was observed upon salicylate induction, although this was shown to be by both mar-dependent and mar-independent pathways. Cyclohexane resistance, however, was induced by salicylate by a mar-dependent pathway. Complementation studies with a plasmid that constitutively expressed marA confirmed the involvement of mar in Salmonella with low-level antibiotic resistance and cyclohexane resistance, although the involvement of mar in down regulation of OmpF was unclear. However, marA overexpression did increase the expression of a ca. 50-kDa protein, but its identity remains to be elucidated. Passage of the marA::gfp reporter mutant with increasing levels of tetracycline, a method reported to select for mar mutants in Escherichia coli, led to both multiple-antibiotic and cyclohexane resistance. Collectively, these data indicate that low-level antibiotic resistance, cyclohexane resistance, and modulation of OMPs in Salmonella, as in E. coli, can occur in both a mar-dependent and mar-independent manner. PMID:11229910

  3. Heat-labile enterotoxin of Escherichia coli promotes intestinal colonization of Salmonella enterica.

    PubMed

    Verbrugghe, Elin; Van Parys, Alexander; Leyman, Bregje; Boyen, Filip; Arnouts, Sven; Lundberg, Urban; Ducatelle, Richard; Van den Broeck, Wim; Yekta, Maryam Atef; Cox, Eric; Haesebrouck, Freddy; Pasmans, Frank

    2015-12-01

    Enterotoxigenic Escherichia coli (ETEC) is an important cause of infantile and travellers' diarrhoea, which poses a serious health burden, especially in developing countries. In addition, ETEC bacteria are a major cause of illness and death in neonatal and recently weaned pigs. The production of a heat-labile enterotoxin (LT) promotes the colonization and pathogenicity of ETEC and may exacerbate co-infections with other enteric pathogens such as Salmonella enterica. We showed that the intraintestinal presence of LT dramatically increased the intestinal Salmonella Typhimurium load in experimentally inoculated pigs. This could not be explained by direct alteration of the invasion or survival capacity of Salmonella in enterocytes, in vitro. However, we demonstrated that LT affects the enteric mucus layer composition in a mucus-secreting goblet cell line by significantly decreasing the expression of mucin 4. The current results show that LT alters the intestinal mucus composition and aggravates a Salmonella Typhimurium infection, which may result in the exacerbation of the diarrhoeal illness. PMID:26616654

  4. Experimental identification and characterization of 97 novel npcRNA candidates in Salmonella enterica serovar Typhi

    PubMed Central

    Chinni, Suresh V.; Raabe, Carsten A.; Zakaria, Robaiza; Randau, Gerrit; Hoe, Chee Hock; Zemann, Anja; Brosius, Juergen; Tang, Thean-Hock; Rozhdestvensky, Timofey S.

    2010-01-01

    We experimentally identified and characterized 97 novel, non-protein-coding RNA candidates (npcRNAs) from the human pathogen Salmonella enterica serovar Typhi (hereafter referred to as S. typhi). Three were specific to S. typhi, 22 were restricted to Salmonella species and 33 were differentially expressed during S. typhi growth. We also identified Salmonella Pathogenicity Island-derived npcRNAs that might be involved in regulatory mechanisms of virulence, antibiotic resistance and pathogenic specificity of S. typhi. An in-depth characterization of S. typhi StyR-3 npcRNA showed that it specifically interacts with RamR, the transcriptional repressor of the ramA gene, which is involved in the multidrug resistance (MDR) of Salmonella. StyR-3 interfered with RamR–DNA binding activity and thus potentially plays a role in regulating ramA gene expression, resulting in the MDR phenotype. Our study also revealed a large number of cis-encoded antisense npcRNA candidates, supporting previous observations of global sense–antisense regulatory networks in bacteria. Finally, at least six of the npcRNA candidates interacted with the S. typhi Hfq protein, supporting an important role of Hfq in npcRNA networks. This study points to novel functional npcRNA candidates potentially involved in various regulatory roles including the pathogenicity of S. typhi. PMID:20460466

  5. Genomic Variability of Serial Human Isolates of Salmonella enterica Serovar Typhimurium Associated with Prolonged Carriage

    PubMed Central

    Octavia, Sophie; Wang, Qinning; Tanaka, Mark M.

    2015-01-01

    Salmonella enterica serovar Typhimurium is an important foodborne human pathogen that often causes self-limiting but severe gastroenteritis. Prolonged excretion of S. Typhimurium after the infection can lead to secondary transmissions. However, little is known about within-host genomic variation in bacteria associated with asymptomatic shedding. Genomes of 35 longitudinal isolates of S. Typhimurium recovered from 11 patients (children and adults) with culture-confirmed gastroenteritis were sequenced. There were three or four isolates obtained from each patient. Single nucleotide polymorphisms (SNPs) were analyzed in these isolates, which were recovered between 1 and 279 days after the initial diagnosis. Limited genomic variation (5 SNPs or fewer) was associated with short- and long-term carriage of S. Typhimurium. None of the isolates was shown to be due to reinfection. SNPs occurred randomly, and the majority of the SNPs were nonsynonymous. Two nonsense mutations were observed. A nonsense mutation in flhC rendered the isolate nonmotile, whereas the significance of a nonsense mutation in yihV is unknown. The estimated mutation rate is 1.49 × 10−6 substitution per site per year. S. Typhimurium isolates excreted in stools following acute gastroenteritis in children and adults demonstrated limited genomic variability over time, regardless of the duration of carriage. These findings have important implications for the detection of possible transmission events suspected by public health genomic surveillance of S. Typhimurium infections. PMID:26311853

  6. Kinetics of the natural, humoral immune response to Salmonella enterica serovar Typhi in Kathmandu, Nepal.

    PubMed

    Pulickal, Anoop S; Gautam, Samir; Clutterbuck, Elizabeth A; Thorson, Stephen; Basynat, Buddha; Adhikari, Neelam; Makepeace, Katherine; Rijpkema, Sjoerd; Borrow, Ray; Farrar, Jeremy J; Pollard, Andrew J

    2009-10-01

    Typhoid fever is a major public health problem in developing countries, conservatively estimated to occur in 17 million cases and be responsible for 200,000 deaths annually. We investigated the acquisition of natural immunity to Salmonella enterica serovar Typhi in a region where typhoid is endemic by testing sera from an age-stratified sample of 210 healthy participants in Kathmandu, Nepal, for bactericidal activity toward S. Typhi and for anti-Vi capsular polysaccharide antibodies. Bactericidal titers in children were significantly lower than those in newborns and adults (P < 0.0001). Anti-S. Typhi bactericidal geometric mean titers were age dependent, increasing 10-fold during childhood. Anti-Vi polysaccharide antibody geometric mean concentrations were also lower in children than in adults. Data presented here indicate the possibility of a relationship between low levels of bactericidal activity toward S. Typhi in serum and susceptibility to disease, as observed for other polysaccharide-encapsulated bacteria. Bactericidal antibody may be a marker of protective immunity against S. Typhi. PMID:19710294

  7. Increased Persistence of Salmonella enterica Serovar Typhi in the Presence of Acanthamoeba castellanii▿

    PubMed Central

    Douesnard-Malo, Frédéric; Daigle, France

    2011-01-01

    Salmonella enterica serovar Typhi (S. Typhi) is the etiological agent of the systemic disease typhoid fever. Transmission occurs via ingestion of contaminated food or water. S. Typhi is specific to humans, and no animal or environmental reservoirs are known. As the free-living amoeba Acanthamoeba castellanii is an environmental host for many pathogenic bacteria, this study investigates interactions between S. Typhi and A. castellanii by using cocultures. Growth of both organisms was estimated by cell count, viable count, flow cytometry, and fluorescence microscopy. Results indicate that S. Typhi can survive at least 3 weeks when grown with A. castellanii, as opposed to less than 10 days when grown as singly cultured bacteria under the same conditions. Interestingly, growth rates of amoebae after 14 days were similar in cocultures or when amoebae were singly cultured, suggesting that S. Typhi is not cytotoxic to A. castellanii. Bacteria surviving in coculture were not intracellular and did not require a physical contact with amoebae for their survival. These results suggest that S. Typhi may have a selective advantage when it is associated with A. castellanii and that amoebae may contribute to S. Typhi persistence in the environment. PMID:21926221

  8. Salmonella enterica Serovar Typhimurium Invades Fibroblasts by Multiple Routes Differing from the Entry into Epithelial Cells▿

    PubMed Central

    Aiastui, Ana; Pucciarelli, M. Graciela; García-del Portillo, Francisco

    2010-01-01

    Fibroblasts are ubiquitous cells essential to tissue homeostasis. Despite their nonphagocytic nature, fibroblasts restrain replication of intracellular bacterial pathogens such as Salmonella enterica serovar Typhimurium. The extent to which the entry route of the pathogen determines this intracellular response is unknown. Here, we analyzed S. Typhimurium invasion in fibroblasts obtained from diverse origins, including primary cultures and stable nontransformed cell lines derived from normal tissues. Features distinct to the invasion of epithelial cells were found in all fibroblasts tested. In some fibroblasts, bacteria lacking the type III secretion system encoded in the Salmonella pathogenicity island 1 displayed significant invasion rates and induced the formation of lamellipodia and filopodia at the fibroblast-bacteria contact site. Other bacterial invasion traits observed in fibroblasts were the requirement of phosphatidylinositol 3-kinase, mitogen-activated protein kinase MEK1, and both actin filaments and microtubules. RNA interference studies showed that different Rho family GTPases are targeted by S. Typhimurium to enter into distinct fibroblasts. Rac1 and Cdc42 knockdown affected invasion of normal rat kidney fibroblasts, whereas none of the GTPases tested (Rac1, Cdc42, RhoA, or RhoG) was essential for invasion of immortalized human foreskin fibroblasts. Collectively, these data reveal a marked diversity in the modes used by S. Typhimurium to enter into fibroblasts. PMID:20368348

  9. Interleukin-17A is required to suppress invasion of Salmonella enterica serovar Typhimurium to enteric mucosa

    PubMed Central

    Mayuzumi, Hirokazu; Inagaki-Ohara, Kyoko; Uyttenhove, Catherine; Okamoto, Yuko; Matsuzaki, Goro

    2010-01-01

    Salmonella enterica serovar Typhimurium (S. typhimurium) causes a localized enteric infection and its elimination is dependent on a T helper type 1 immune response. However, the mechanism of the protective immune response against the pathogen in gut-associated lymphoid tissue (GALT) at an early stage of the infection is not yet clarified. Here, we show that interleukin-17A (IL-17A) was constitutively expressed in GALT; it was also detected on crypt and epithelial cells of the small intestine. Neutralization of the IL-17A in the intestinal lumen exacerbated epithelial damage induced by intestinal S. typhimurium infection at an early stage of the infection. The result suggests that IL-17A has a pivotal role in the immediate early stage of protection against bacterial infection at the intestinal mucosa. As IL-17A neutralization also suppressed the constitutive localization of β-defensin 3 (BD3), an IL-17A-induced antimicrobial peptide, at the apical site of the intestinal mucosa, it is estimated that IL-17A constitutively induces the expression of the antimicrobial peptide to kill invading pathogens at the epithelial surface immediately after the infection. In contrast, interferon-γ is induced around 3 days after S. typhimurium infection, and its expression level increases thereafter. Taken together, the findings lead to the hypothesis that IL-17A participates in the immediate early stage of protection against S. typhimurium intestinal infection whereas interferon-γ is important at a later stage of the infection. PMID:20575990

  10. Changes in the Salmonella enterica Enteritidis phenotypes in presence of acyl homoserine lactone quorum sensing signals.

    PubMed

    Campos-Galvão, Maria Emilene Martino; Ribon, Andrea Oliveira Barros; Araújo, Elza Fernandes; Vanetti, Maria Cristina Dantas

    2016-05-01

    Quorum sensing is used by bacteria to coordinate gene expression in response to population density and involves the production, detection and response to extracellular signaling molecules known as autoinducers (AIs). Salmonella does not synthesize the AI-1, acyl homoserine lactone (AHL) common to gram-negative bacteria; however, it has a receptor for AI-1, the SdiA protein. The effect of SdiA in modulating phenotypes of Salmonella has not been elucidated. In this report, we provide evidence that the AIs-1 affect Salmonella enterica serovar Enteritidis behavior by enhancing the biofilm formation and expression of virulence genes under anaerobic conditions. Biofilm formation by Salmonella was detected by the crystal violet method and by scanning electron microscopy. The presence of AHLs, particularly C12-HSL, increased biofilm formation and promoted expression of biofilm formation genes (lpfA, fimF, fliF, glgC) and virulence genes (hilA, invA, invF). Our results demonstrated that AHLs produced by other organisms played an important role in virulence phenotypes of Salmonella Enteritidis. PMID:26662614

  11. Antimicrobial Drug Resistance and Molecular Typing of Salmonella enterica Serovar Rissen from Different Sources.

    PubMed

    García-Fierro, Raquel; Montero, Ignacio; Bances, Margarita; González-Hevia, Maria Ángeles; Rodicio, María Rosario

    2016-04-01

    Salmonella enterica serovar Rissen is one of the most common serovars found in pigs and pork products in different countries, including Spain. However, information on the molecular bases of antimicrobial drug resistance and the population structure of Salmonella Rissen from different sources in Spain is limited. The present study focused on 84 isolates collected in Spain from pig and beef carcasses, foods and clinical samples associated with sporadic cases of gastroenteritis, and one outbreak. The majority of the isolates were resistant to tetracycline (73.8%), mainly conferred by tet(A). Resistances to streptomycin (aadA1-like, aadA2, and strAB), sulfonamides (sul1, sul2, and sul3), trimethoprim (dfrA1-like and dfrA12), ampicillin (blaTEM-1-like), and chloramphenicol (cmlA1-like) were also detected, with frequencies ranging from 12% to 20.2%. Most of the identified genes were carried by integrons, including three class 1 integrons of the sul1 type, a class 1 integron of the sul3 type, and the class 2 integron of Tn7. Two sul1 integrons, the sul3 integron, and the class 2 integron are first reported in Salmonella Rissen. Typing of the isolates with XbaI pulsed-field gel electrophoresis detected a major clone, which was circulating in humans and animals during the past decade, and was responsible for the outbreak. The obtained results are relevant for food safety and public health. PMID:26295933

  12. Deletion of Invasion Protein B in Salmonella enterica Serovar Typhimurium Influences Bacterial Invasion and Virulence.

    PubMed

    Chen, Songbiao; Zhang, Chunjie; Liao, Chengshui; Li, Jing; Yu, Chuan; Cheng, Xiangchao; Yu, Zuhua; Zhang, Mingliang; Wang, Yang

    2015-12-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) has a wide host range and causes infections ranging from severe gastroenteritis to systemic infections in human, as well as causing typhoid-like disease in murine models of infection. S. Typhimurium translocates its effector proteins through the Salmonella pathogenicity island-I (SPI-I)-encoded T3SS-I needle complex. This study focuses on invasion protein B (SipB) of S. Typhimurium, which plays an active role in SPI-I invasion efficiency. To test our hypothesis, a sipB deletion mutant was constructed through double-crossover allelic using the suicide vector pRE112ΔsipB, and its biological characteristics were analyzed. The results showed that the SipB does not affect the growth of Salmonella, but the adherence, invasion, and virulence of the mutant were significantly decreased compared with wild-type S. Typhimurium (SL1344). This research indicates that SipB is an important virulence factor in the pathogenicity of S. Typhimurium. PMID:26341924

  13. High-throughput Assay to Phenotype Salmonella enterica Typhimurium Association, Invasion, and Replication in Macrophages

    PubMed Central

    Wu, Jing; Pugh, Roberta; Laughlin, Richard C.; Andrews-Polymenis, Helene; McClelland, Michael; Bäumler, Andreas J.; Adams, L. Garry

    2014-01-01

    Salmonella species are zoonotic pathogens and leading causes of food borne illnesses in humans and livestock1. Understanding the mechanisms underlying Salmonella-host interactions are important to elucidate the molecular pathogenesis of Salmonella infection. The Gentamicin protection assay to phenotype Salmonella association, invasion and replication in phagocytic cells was adapted to allow high-throughput screening to define the roles of deletion mutants of Salmonella enterica serotype Typhimurium in host interactions using RAW 264.7 murine macrophages. Under this protocol, the variance in measurements is significantly reduced compared to the standard protocol, because wild-type and multiple mutant strains can be tested in the same culture dish and at the same time. The use of multichannel pipettes increases the throughput and enhances precision. Furthermore, concerns related to using less host cells per well in 96-well culture dish were addressed. Here, the protocol of the modified in vitro Salmonella invasion assay using phagocytic cells was successfully employed to phenotype 38 individual Salmonella deletion mutants for association, invasion and intracellular replication. The in vitro phenotypes are presented, some of which were subsequently confirmed to have in vivo phenotypes in an animal model. Thus, the modified, standardized assay to phenotype Salmonella association, invasion and replication in macrophages with high-throughput capacity could be utilized more broadly to study bacterial-host interactions. PMID:25146526

  14. Host Transmission of Salmonella enterica Serovar Typhimurium Is Controlled by Virulence Factors and Indigenous Intestinal Microbiota▿

    PubMed Central

    Lawley, Trevor D.; Bouley, Donna M.; Hoy, Yana E.; Gerke, Christine; Relman, David A.; Monack, Denise M.

    2008-01-01

    Transmission is an essential stage of a pathogen's life cycle and remains poorly understood. We describe here a model in which persistently infected 129X1/SvJ mice provide a natural model of Salmonella enterica serovar Typhimurium transmission. In this model only a subset of the infected mice, termed supershedders, shed high levels (>108 CFU/g) of Salmonella serovar Typhimurium in their feces and, as a result, rapidly transmit infection. While most Salmonella serovar Typhimurium-infected mice show signs of intestinal inflammation, only supershedder mice develop colitis. Development of the supershedder phenotype depends on the virulence determinants Salmonella pathogenicity islands 1 and 2, and it is characterized by mucosal invasion and, importantly, high luminal abundance of Salmonella serovar Typhimurium within the colon. Immunosuppression of infected mice does not induce the supershedder phenotype, demonstrating that the immune response is not the main determinant of Salmonella serovar Typhimurium levels within the colon. In contrast, treatment of mice with antibiotics that alter the health-associated indigenous intestinal microbiota rapidly induces the supershedder phenotype in infected mice and predisposes uninfected mice to the supershedder phenotype for several days. These results demonstrate that the intestinal microbiota plays a critical role in controlling Salmonella serovar Typhimurium infection, disease, and transmissibility. This novel model should facilitate the study of host, pathogen, and intestinal microbiota factors that contribute to infectious disease transmission. PMID:17967858

  15. Expression divergence between Escherichia coli and Salmonella enterica serovar Typhimurium reflects their lifestyles.

    PubMed

    Meysman, Pieter; Sánchez-Rodríguez, Aminael; Fu, Qiang; Marchal, Kathleen; Engelen, Kristof

    2013-06-01

    Escherichia coli K12 is a commensal bacteria and one of the best-studied model organisms. Salmonella enterica serovar Typhimurium, on the other hand, is a facultative intracellular pathogen. These two prokaryotic species can be considered related phylogenetically, and they share a large amount of their genetic material, which is commonly termed the "core genome." Despite their shared core genome, both species display very different lifestyles, and it is unclear to what extent the core genome, apart from the species-specific genes, plays a role in this lifestyle divergence. In this study, we focus on the differences in expression domains for the orthologous genes in E. coli and S. Typhimurium. The iterative comparison of coexpression methodology was used on large expression compendia of both species to uncover the conservation and divergence of gene expression. We found that gene expression conservation occurs mostly independently from amino acid similarity. According to our estimates, at least more than one quarter of the orthologous genes has a different expression domain in E. coli than in S. Typhimurium. Genes involved with key cellular processes are most likely to have conserved their expression domains, whereas genes showing diverged expression are associated with metabolic processes that, although present in both species, are regulated differently. The expression domains of the shared "core" genome of E. coli and S. Typhimurium, consisting of highly conserved orthologs, have been tuned to help accommodate the differences in lifestyle and the pathogenic potential of Salmonella. PMID:23427276

  16. Cellular Requirements for Systemic Control of Salmonella enterica Serovar Typhimurium Infections in Mice

    PubMed Central

    Bedoui, Sammy

    2014-01-01

    The rational design of vaccines requires an understanding of the contributions of individual immune cell subsets to immunity. With this understanding, targeted vaccine delivery approaches and adjuvants can be developed to maximize vaccine efficiency and to minimize side effects (S. H. E. Kaufmann et al., Immunity 33:555–577, 2010; T. Ben-Yedidia and R. Arnon, Hum. Vaccines 1:95–101, 2005). We have addressed the contributions of different immune cell subsets and their ability to contribute to the control and clearance of the facultative intracellular pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) in a murine model. Using a systematic and reproducible model of experimental attenuated S. Typhimurium infection, we show that distinct lymphocyte deficiencies lead to one of four different infection outcomes: clearance, chronic infection, early death, or late death. Our study demonstrates a high level of functional redundancy in the ability of different lymphocyte subsets to provide interferon gamma (IFN-γ), a critical cytokine in Salmonella immunity. Whereas early control of the infection was entirely dependent on IFN-γ but not on any particular lymphocyte subset, clearance of the infection critically required CD4+ T cells but appeared to be independent of IFN-γ. These data reinforce the idea of a bimodal immune response against Salmonella: an early T cell-independent but IFN-γ-dependent phase and a late T cell-dependent phase that may be IFN-γ independent. PMID:25225248

  17. MdsABC-Mediated Pathway for Pathogenicity in Salmonella enterica Serovar Typhimurium

    PubMed Central

    Song, Saemee; Lee, Boeun; Yeom, Ji-Hyun; Hwang, Soonhye; Kang, Ilnam; Cho, Jang-Cheon; Ha, Nam-Chul; Bae, Jeehyeon

    2015-01-01

    MdsABC is a Salmonella-specific tripartite efflux pump that has been implicated in the virulence of Salmonella enterica serovar Typhimurium; however, little is known about the virulence factors associated with this pump. We observed MdsABC expression-dependent alterations in the degree of resistance to extracellular oxidative stress and macrophage-mediated killing. Thin-layer chromatography and tandem mass spectrometry analyses revealed that overexpression of MdsABC led to increased secretion of 1-palmitoyl-2-stearoyl-phosphatidylserine (PSPS), affecting the ability of the bacteria to invade and survive in host cells. Overexpression of MdsABC and external addition of PSPS similarly rendered the mdsABC deletion strain resistant to diamide. Diagonal gel analysis showed that PSPS treatment reduced the diamide-mediated formation of disulfide bonds, particularly in the membrane fraction of the bacteria. Salmonella infection of macrophages induced the upregulation of MdsABC expression and led to an increase of intracellular bacterial number and host cell death, similar to the effects of MdsABC overexpression and PSPS pretreatment on the mdsABC deletion strain. Our study shows that MdsABC mediates a previously uncharacterized pathway that involves PSPS as a key factor for the survival and virulence of S. Typhimurium in phagocytic cells. PMID:26283336

  18. Interaction of graphene family materials with Listeria monocytogenes and Salmonella enterica

    NASA Astrophysics Data System (ADS)

    Kurantowicz, Natalia; Sawosz, Ewa; Jaworski, Sławomir; Kutwin, Marta; Strojny, Barbara; Wierzbicki, Mateusz; Szeliga, Jacek; Hotowy, Anna; Lipińska, Ludwika; Koziński, Rafał; Jagiełło, Joanna; Chwalibog, André

    2015-01-01

    Graphene family materials have unique properties, which make them valuable for a range of applications. The antibacterial properties of graphene have been reported; however, findings have been contradictory. This study reports on the antimicrobial proprieties of three different graphene materials (pristine graphene (pG), graphene oxide (GO), and reduced graphene oxide (rGO)) against the food-borne bacterial pathogens Listeria monocytogenes and Salmonella enterica. A high concentration (250 μg/mL) of all the analyzed graphenes completely inhibited the growth of both pathogens, despite their difference in bacterial cell wall structure. At a lower concentration (25 μg/mL), similar effects were only observed with GO, as growth inhibition decreased with pG and rGO at the lower concentration. Interaction of the nanoparticles with the pathogenic bacteria was found to differ depending on the form of graphene. Microscopic imaging demonstrated that bacteria were arranged at the edges of pG and rGO, while with GO, they adhered to the nanoparticle surface. GO was found to have the highest antibacterial activity.

  19. Proteome of Salmonella enterica serotype Tyhimurium Grown in Low Mg2+/pH Medium

    SciTech Connect

    Shi, Liang; Ansong, Charles; Smallwood, Heather S.; Rommereim, Leah M.; McDermott, Jason E.; Brewer, Heather M.; Norbeck, Angela D.; Taylor, Ronald C.; Gustin, Jean K.; Heffron, Fred; Smith, Richard D.; Adkins, Joshua N.

    2009-09-04

    To determine the impact of a low Mg2+/pH defined growth medium (MgM) on the proteome of Salmonella enterica serotype Typhimurium, we cultured S. Typhimurium cells in the medium under two different conditions termed MgM Shock and MgM Dilution and then comparatively analyzed the bacterial cells harvested from these conditions by a global proteomic approach. Proteomic results showed that MgM Shock and MgM Dilution differentially affected the S. Typhimurium proteome. MgM Shock induced a group of proteins whose induction usually occurred at low O2 level, while MgM Dilution induced those related to the type III secretion system (T3SS) of Salmonella Pathogenicity Island 2 (SPI2) and those involved in thiamine or biotin biosynthesis. The metabolic state of the S. Typhimurium cells grown under MgM Shock condition also differed significantly from that under MgM Dilution condition. Western blot analysis not only confirmed the proteomic results, but also showed that the abundances of SPI2-T3SS proteins SsaQ and SseE and biotin biosynthesis proteins BioB and BioD increased after S. Typhimurium infection of RAW 264.7 macrophages. Deletion of the gene encoding BioB reduced the bacterial ability to replicate inside the macrophages, suggesting a biotin-limited environment encountered by S. Typhimurium within RAW 264.7 macrophages.

  20. Salmonella enterica isolates from layer farm environments are able to form biofilm on eggshell surfaces.

    PubMed

    Pande, Vivek V; McWhorter, Andrea R; Chousalkar, Kapil K

    2016-08-01

    This study examined the eggshell biofilm forming ability of Salmonella enterica isolates recovered from egg farms. Multicellular behaviour and biofilm production were examined at 22 and 37°C by Congo red morphology and the crystal violet staining assay. The results indicated that the biofilm forming behaviour of Salmonella isolates was dependent on temperature and associated with serovars. Significantly greater biofilm production was observed at 22°C compared with 37°C. The number of viable biofilm cells attached to eggshells after incubation for 48 h at 22°C was significantly influenced by serovar. Scanning electron microscopic examination revealed firm attachment of bacterial cells to the eggshell surface. The relative expression of csgD and adrA gene was significantly higher in eggshell biofilm cells of S. Mbandaka and S. Oranienburg. These findings demonstrate that Salmonella isolates are capable of forming biofilm on the eggshell surface and that this behaviour is influenced by temperature and serovar. PMID:27268931

  1. Genetic and phenotypic evidence of the Salmonella enterica serotype Enteritidis human-animal interface in Chile.

    PubMed

    Retamal, Patricio; Fresno, Marcela; Dougnac, Catherine; Gutierrez, Sindy; Gornall, Vanessa; Vidal, Roberto; Vernal, Rolando; Pujol, Myriam; Barreto, Marlen; González-Acuña, Daniel; Abalos, Pedro

    2015-01-01

    Salmonella enterica serotype Enteritidis is a worldwide zoonotic agent that has been recognized as a very important food-borne bacterial pathogen, mainly associated with consumption of poultry products. The aim of this work was to determine genotypic and phenotypic evidence of S. Enteritidis transmission among seabirds, poultry and humans in Chile. Genotyping was performed using PCR-based virulotyping, pulse-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Pathogenicity-associated phenotypes were determined with survival to free radicals, acidic pH, starvation, antimicrobial resistance, and survival within human dendritic cells. As result of PCR and PFGE assays, some isolates from the three hosts showed identical genotypic patterns, and through MLST it was determined that all of them belong to sequence type 11. Phenotypic assays show diversity of bacterial responses among isolates. When results were analyzed according to bacterial host, statistical differences were identified in starvation and dendritic cells survival assays. In addition, isolates from seabirds showed the highest rates of resistance to gentamycin, tetracycline, and ampicillin. Overall, the very close genetic and phenotypic traits shown by isolates from humans, poultry, and seabirds suggest the inter-species transmission of S. Enteritidis bacteria between hosts, likely through anthropogenic environmental contamination that determines infection of seabirds with bacteria that are potentially pathogenic for other susceptible organism, including humans. PMID:26029196

  2. Survival of Salmonella enterica in Dried Turkey Manure and Persistence on Spinach Leaves.

    PubMed

    Oni, Ruth A; Sharma, Manan; Buchanan, Robert L

    2015-10-01

    Concerns about the microbiological safety of fresh produce have attracted attention in the past three decades due to multiple foodborne outbreaks. Animal manure contaminated with enteric pathogens has been identified as an important preharvest pathogen source. This study investigated the survival of Salmonella enterica in dust particles of dehydrated turkey manure and how association with manure dust may enhance the survival of salmonellae on leafy greens in the field. The survival of a cocktail of multiple Salmonella serotypes in the dried fecal material of various particle sizes (125 to 500 μm) was examined at varying moisture contents (5, 10, and 15%). Survival times of the pathogen were inversely related to moisture content and particle size of manure dust, with viable Salmonella still detectable for up to 291 days in the smallest particle size (125 μm) with 5% moisture. Association with manure dust particles increased the survival of Salmonella when subjected to UV light both under laboratory conditions and on the surface of spinach leaves in a greenhouse setting. The results of this study suggest that aerosolized manure particles could be a potential vehicle for Salmonella dispersal to leafy greens if the microorganism is present in the dry manure. PMID:26408127

  3. Genetics of Swarming Motility in Salmonella enterica Serovar Typhimurium: Critical Role for Lipopolysaccharide

    PubMed Central

    Toguchi, Adam; Siano, Michael; Burkart, Mark; Harshey, Rasika M.

    2000-01-01

    Salmonella enterica serovar Typhimurium can differentiate into hyperflagellated swarmer cells on agar of an appropriate consistency (0.5 to 0.8%), allowing efficient colonization of the growth surface. Flagella are essential for this form of motility. In order to identify genes involved in swarming, we carried out extensive transposon mutagenesis of serovar Typhimurium, screening for those that had functional flagella yet were unable to swarm. A majority of these mutants were defective in lipopolysaccharide (LPS) synthesis, a large number were defective in chemotaxis, and some had defects in putative two-component signaling components. While the latter two classes were defective in swarmer cell differentiation, representative LPS mutants were not and could be rescued for swarming by external addition of a biosurfactant. A mutation in waaG (LPS core modification) secreted copious amounts of slime and showed a precocious swarming phenotype. We suggest that the O antigen improves surface “wettability” required for swarm colony expansion, that the LPS core could play a role in slime generation, and that multiple two-component systems cooperate to promote swarmer cell differentiation. The failure to identify specific swarming signals such as amino acids, pH changes, oxygen, iron starvation, increased viscosity, flagellar rotation, or autoinducers leads us to consider a model in which the external slime is itself both the signal and the milieu for swarming motility. The model explains the cell density dependence of the swarming phenomenon. PMID:11053374

  4. Models of intestinal infection by Salmonella enterica: introduction of a new neonate mouse model.

    PubMed

    Schulte, Marc; Hensel, Michael

    2016-01-01

    Salmonella enterica serovar Typhimurium is a foodborne pathogen causing inflammatory disease in the intestine following diarrhea and is responsible for thousands of deaths worldwide. Many in vitro investigations using cell culture models are available, but these do not represent the real natural environment present in the intestine of infected hosts. Several in vivo animal models have been used to study the host-pathogen interaction and to unravel the immune responses and cellular processes occurring during infection. An animal model for Salmonella-induced intestinal inflammation relies on the pretreatment of mice with streptomycin. This model is of great importance but still shows limitations to investigate the host-pathogen interaction in the small intestine in vivo. Here, we review the use of mouse models for Salmonella infections and focus on a new small animal model using 1-day-old neonate mice. The neonate model enables researchers to observe infection of both the small and large intestine, thereby offering perspectives for new experimental approaches, as well as to analyze the Salmonella-enterocyte interaction in the small intestine in vivo. PMID:27408697

  5. Physiology, pathogenicity and immunogenicity of live, attenuated Salmonella enterica serovar Enteritidis mutants in chicks.

    PubMed

    Si, Wei; Wang, Xiumei; Liu, Huifang; Yu, Shenye; Li, Zhaoli; Chen, Liping; Zhang, Wanjiang; Liu, Siguo

    2015-01-01

    To construct a novel live, attenuated Salmonella vaccine, the lon, cpxR and cpdB genes were deleted from a wild-type Salmonella enterica serovar Enteritidis-6 (SM-6) strain using the phage λ Red homologous recombination system, resulting in SM-△CpxR, SM-△C/Lon and SM-△C/L/CpdB. The growth curves of strain SM-△C/Lon grew more rapidly than the other strains and had OD 600 values higher than the other strains starting at the 4 h time point. The growth curves of strain SM-△C/L/CpdB were relatively flat. The colonization time of SM-△C/L/CpdB is about 8-10 days. Deleting the lon/cpxR/cpdB (SM-6) genes resulted in an approximate 10(3)-fold attenuation in virulence assessed by the analysis of the LD50 of specific pathogen-free (SPF) chicks. This result indicated that the deletion of the lon, cpxR and cpdB genes induced significant virulence attenuation. The protective effects of SM-△C/L/CpdB vaccination in SPF chicks against 5 × 10(9) colony forming units (CFU) of S. Enteritidis were resulted from the induction of an effective immune response. These findings demonstrate the potential of mutant SM-△C/L/CpdB to be used as an effective vaccine. PMID:25819881

  6. Multiple roles of putrescine and spermidine in stress resistance and virulence of Salmonella enterica serovar Typhimurium.

    PubMed

    Espinel, Irene Cartas; Guerra, Priscila Regina; Jelsbak, Lotte

    2016-06-01

    Polyamines (putrescine and spermidine) are small-cationic amines ubiquitous in nature and present in most living cells. In recent years they have been linked to virulence of several human pathogens including Shigella spp and Salmonella enterica serovar Typhimurium (S. Typhimurium). Central to S. Typhimurium virulence is the ability to survive and replicate inside macrophages and resisting the antimicrobial attacks in the form of oxidative and nitrosative stress elicited from these cells. In the present study, we have investigated the role of polyamines in intracellular survival and systemic infections of mice. Using a S. Typhimurium mutant defective for putrescine and spermidine biosynthesis, we show that polyamines are essential for coping with reactive nitrogen species, possibly linking polyamines to increased intracellular stress resistance. However, using a mouse model defective for nitric oxide production, we find that polyamines are required for systemic infections independently of host-produced reactive nitrogen species. To distinguish between the physiological roles of putrescine and spermidine, we constructed a strain deficient for spermidine biosynthesis and uptake, but with retained ability to produce and import putrescine. Interestingly, in this mutant we observe a strong attenuation of virulence during infection of mice proficient and deficient for nitric oxide production suggesting that spermidine, specifically, is essential for virulence of S. Typhimurium. PMID:27041598

  7. Lack of efflux mediated quinolone resistance in Salmonella enterica serovars Typhi and Paratyphi A.

    PubMed

    Baucheron, Sylvie; Monchaux, Isabelle; Le Hello, Simon; Weill, François-Xavier; Cloeckaert, Axel

    2014-01-01

    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 contributing mechanism for other serovars. Therefore, we investigated also the occurrence of non-target gene mutations in regulatory regions affecting efflux pump expression. However, no mutation was detected in these regions in both Typhi and Paratyphi isolates of this study. Besides, no overexpression of the major efflux systems was observed for these isolates. Nevertheless, a large deletion of 2334 bp was identified in the acrS-acrE region of all S. Typhi strains but which did not affect the resistance phenotype. As being specific to S. Typhi, this deletion could be used for specific molecular detection purposes. In conclusion, the different levels of quinolone or FQ resistance in both S. Typhi and S. Paratyphi A seem to rely only on target modifications. PMID:24478769

  8. Biofilm formation ability of Salmonella enterica serovar Typhimurium acrAB mutants.

    PubMed

    Schlisselberg, Dov B; Kler, Edna; Kisluk, Guy; Shachar, Dina; Yaron, Sima

    2015-10-01

    Recent studies offer contradictory findings about the role of multidrug efflux pumps in bacterial biofilm development. Thus, the aim of this study was to investigate the involvement of the AcrAB efflux pump in biofilm formation by investigating the ability of AcrB and AcrAB null mutants of Salmonella enterica serovar Typhimurium to produce biofilms. Three models were used to compare the ability of S. Typhimurium wild-type and its mutants to form biofilms: formation of biofilm on polystyrene surfaces; production of biofilm (mat model) on the air/liquid interface; and expression of curli and cellulose on Congo red-supplemented agar plates. All three investigated genotypes formed biofilms with similar characteristics. However, upon exposure to chloramphenicol, formation of biofilms on solid surfaces as well as the production of curli were either reduced or were delayed more significantly in both mutants, whilst there was no visible effect on pellicle formation. It can be concluded that when no selective pressure is applied, S. Typhimurium is able to produce biofilms even when the AcrAB efflux pumps are inactivated, implying that the use of efflux pump inhibitors to prevent biofilm formation is not a general solution and that combined treatments might be more efficient. Other factors that affect the ability to produce biofilms depending on efflux pump activity are yet to be identified. PMID:26260191

  9. Antagonistic activity of Lactobacillus acidophilus LA10 against Salmonella enterica serovar Enteritidis SE86 in mice

    PubMed Central

    Scapin, Diane; Grando, Williani Fabiola; Rossi, Eliandra Mirlei; Perez, Karla Joseane; Malheiros, Patrícia da Silva; Tondo, Eduardo Cesar

    2013-01-01

    Salmonella enterica serovar Enteritidis is one of the main pathogens responsible for foodborne illness in Brazil. Probiotic bacteria can play a role in defense and recovery from enteropathogenic infections. In this study, the ability of Lactobacillus acidophilus LA10 to colonise and exert antagonistic effects in the gastrointestinal tract was tested before and during experimental infection in conventional mice contaminated with S. Enteritidis (SE86). A dose of 0.1 mL containing 108 viable cells of SE86 and L. acidophilus LA10 was orally administered by gavage to mice. The experiment was divided into groups. As a negative control, Group 1 was administered only sterile saline solution. As a positive control, Group 2 was administered only SE86. Group 3 was first administered SE86, and after 10 days, treated with L. acidophilus LA10. Group 4 was first administered L. acidophilus LA10, and after 10 days, challenged with SE86. The results demonstrated that a significant number of SE86 cells were able to colonize the gastrointestinal tract of mice, specifically in the colon and ileum. L. acidophilus LA10 demonstrated an antagonistic effect against SE86, with better results observed for Group 3 over Group 4. Thus, L. acidophilus LA10 shows potential antagonistic effects against S. Enteritidis SE86, especially if administered after infection. PMID:24159284

  10. Temperate phages promote colicin-dependent fitness of Salmonella enterica serovar Typhimurium.

    PubMed

    Nedialkova, Lubov P; Sidstedt, Maja; Koeppel, Martin B; Spriewald, Stefanie; Ring, Diana; Gerlach, Roman G; Bossi, Lionello; Stecher, Bärbel

    2016-05-01

    Bacteria employ bacteriocins for interference competition in microbial ecosystems. Colicin Ib (ColIb), a pore-forming bacteriocin, confers a significant fitness benefit to Salmonella enterica serovar Typhimurium (S. Tm) in competition against commensal Escherichia coli in the gut. ColIb is released from S. Tm into the environment, where it kills susceptible competitors. However, colicin-specific release proteins, as they are known for other colicins, have not been identified in case of ColIb. Thus, its release mechanism has remained unclear. In the current study, we have established a new link between ColIb release and lysis activity of temperate, lambdoid phages. By the use of phage-cured S. Tm mutant strains, we show that the presence of temperate phages and their lysis genes is necessary and sufficient for release of active ColIb into the culture supernatant. Furthermore, phage-mediated lysis significantly enhanced S. Tm fitness in competition against a ColIb-susceptible competitor. Finally, transduction with the lambdoid phage 933W rescued the defect of E. coli strain MG1655 with respect to ColIb release. In conclusion, ColIb is released from bacteria in the course of phage lysis. Our data reveal a new mechanism for colicin release and point out a novel function of temperate phages in enhancing colicin-dependent bacterial fitness. PMID:26439675

  11. Salmonella enterica Serovar Typhimurium Skills To Succeed in the Host: Virulence and Regulation

    PubMed Central

    Fàbrega, Anna

    2013-01-01

    SUMMARY Salmonella enterica serovar Typhimurium is a primary enteric pathogen infecting both humans and animals. Infection begins with the ingestion of contaminated food or water so that salmonellae reach the intestinal epithelium and trigger gastrointestinal disease. In some patients the infection spreads upon invasion of the intestinal epithelium, internalization within phagocytes, and subsequent dissemination. In that case, antimicrobial therapy, based on fluoroquinolones and expanded-spectrum cephalosporins as the current drugs of choice, is indicated. To accomplish the pathogenic process, the Salmonella chromosome comprises several virulence mechanisms. The most important virulence genes are those located within the so-called Salmonella pathogenicity islands (SPIs). Thus far, five SPIs have been reported to have a major contribution to pathogenesis. Nonetheless, further virulence traits, such as the pSLT virulence plasmid, adhesins, flagella, and biofilm-related proteins, also contribute to success within the host. Several regulatory mechanisms which synchronize all these elements in order to guarantee bacterial survival have been described. These mechanisms govern the transitions from the different pathogenic stages and drive the pathogen to achieve maximal efficiency inside the host. This review focuses primarily on the virulence armamentarium of this pathogen and the extremely complicated regulatory network controlling its success. PMID:23554419

  12. SOS System Induction Inhibits the Assembly of Chemoreceptor Signaling Clusters in Salmonella enterica

    PubMed Central

    Irazoki, Oihane; Mayola, Albert; Campoy, Susana; Barbé, Jordi

    2016-01-01

    Swarming, a flagellar-driven multicellular form of motility, is associated with bacterial virulence and increased antibiotic resistance. In this work we demonstrate that activation of the SOS response reversibly inhibits swarming motility by preventing the assembly of chemoreceptor-signaling polar arrays. We also show that an increase in the concentration of the RecA protein, generated by SOS system activation, rather than another function of this genetic network impairs chemoreceptor polar cluster formation. Our data provide evidence that the molecular balance between RecA and CheW proteins is crucial to allow polar cluster formation in Salmonella enterica cells. Thus, activation of the SOS response by the presence of a DNA-injuring compound increases the RecA concentration, thereby disturbing the equilibrium between RecA and CheW and resulting in the cessation of swarming. Nevertheless, when the DNA-damage decreases and the SOS response is no longer activated, basal RecA levels and thus polar cluster assembly are reestablished. These results clearly show that bacterial populations moving over surfaces make use of specific mechanisms to avoid contact with DNA-damaging compounds. PMID:26784887

  13. Selection of Orphan Rhs Toxin Expression in Evolved Salmonella enterica Serovar Typhimurium

    PubMed Central

    Koskiniemi, Sanna; Garza-Sánchez, Fernando; Sandegren, Linus; Webb, Julia S.; Braaten, Bruce A.; Poole, Stephen J.; Andersson, Dan I.; Hayes, Christopher S.; Low, David A.

    2014-01-01

    Clonally derived bacterial populations exhibit significant genotypic and phenotypic diversity that contribute to fitness in rapidly changing environments. Here, we show that serial passage of Salmonella enterica serovar Typhimurium LT2 (StLT2) in broth, or within a mouse host, results in selection of an evolved population that inhibits the growth of ancestral cells by direct contact. Cells within each evolved population gain the ability to express and deploy a cryptic “orphan” toxin encoded within the rearrangement hotspot (rhs) locus. The Rhs orphan toxin is encoded by a gene fragment located downstream of the “main” rhs gene in the ancestral strain StLT2. The Rhs orphan coding sequence is linked to an immunity gene, which encodes an immunity protein that specifically blocks Rhs orphan toxin activity. Expression of the Rhs orphan immunity protein protects ancestral cells from the evolved lineages, indicating that orphan toxin activity is responsible for the observed growth inhibition. Because the Rhs orphan toxin is encoded by a fragmented reading frame, it lacks translation initiation and protein export signals. We provide evidence that evolved cells undergo recombination between the main rhs gene and the rhs orphan toxin gene fragment, yielding a fusion that enables expression and delivery of the orphan toxin. In this manner, rhs locus rearrangement provides a selective advantage to a subpopulation of cells. These observations suggest that rhs genes play important roles in intra-species competition and bacterial evolution. PMID:24675981

  14. Rescuing chemotaxis of the anticancer agent Salmonella enterica serovar Typhimurium VNP20009.

    PubMed

    Broadway, Katherine M; Denson, Elizabeth A P; Jensen, Roderick V; Scharf, Birgit E

    2015-10-10

    The role of chemotaxis and motility in Salmonella enterica serovar Typhimurium tumor colonization remains unclear. We determined through swim plate assays that the well-established anticancer agent S. Typhimurium VNP20009 is deficient in chemotaxis, and that this phenotype is suppressible. Through genome sequencing, we revealed that VNP20009 and four selected suppressor mutants had a single nucleotide polymorphism (SNP) in cheY causing a mutation in the conserved proline residue at position 110. CheY is the response regulator that interacts with the flagellar motor-switch complex and modulates rotational bias. The four suppressor mutants additionally carried non-synonymous SNPs in fliM encoding a flagellar switch protein. The CheY-P110S mutation in VNP20009 likely rendered the protein unable to interact with FliM, a phenotype that could be suppressed by mutations in FliM. We replaced the mutated cheY in VNP20009 with the wild-type copy and chemotaxis was partially restored. The swim ring of the rescued strain, VNP20009 cheY(+), was 46% the size of the parental strain 14028 swim ring. When tested in capillary assays, VNP20009 cheY(+) was 69% efficient in chemotaxis towards the attractant aspartate as compared to 14028. Potential reasons for the lack of complete restoration and implications for bacterial tumor colonization will be discussed. PMID:26200833

  15. Evidence for an Efflux Pump Mediating Multiple Antibiotic Resistance in Salmonella enterica Serovar Typhimurium

    PubMed Central

    Piddock, Laura J. V.; White, David G.; Gensberg, Karl; Pumbwe, Lilian; Griggs, Deborah J.

    2000-01-01

    The mechanism of multiple antibiotic resistance in six isolates of Salmonella enterica serovar Typhimurium recovered from a patient treated with ciprofloxacin was studied to investigate the role of efflux in the resistance phenotype. Compared to the patient's pretherapy isolate (L3), five of six isolates accumulated less ciprofloxacin, three of six isolates accumulated less chloramphenicol, and all six accumulated less tetracycline. The accumulation of one or more antibiotics was increased by carbonyl cyanide m-chlorophenylhydrazone to concentrations similar to those accumulated by L3 for all isolates except one, in which accumulation of all three agents remained approximately half that of L3. All isolates had the published wild-type sequences of marO and marR. No increased expression of marA, tolC, or soxS was observed by Northern blotting; however, three isolates showed increased expression of acrB, which was confirmed by quantitative competitive reverse transcription-PCR. However, there were no mutations within acrR or the promoter region of acrAB in any of the isolates. PMID:11036033

  16. Salmonella enterica Invasion of Polarized Epithelial Cells Is a Highly Cooperative Effort

    PubMed Central

    Lorkowski, Martin; Felipe-López, Alfonso; Danzer, Claudia A.; Hansmeier, Nicole

    2014-01-01

    The invasion of polarized epithelial cells by Salmonella enterica requires the cooperative activity of the Salmonella pathogenicity island 1 (SPI1)-encoded type III secretion system (T3SS) and the SPI4-encoded adhesin SiiE. The invasion of polarized cells is more efficient than that of nonpolarized cells, and we observed the formation of clusters of bacteria on infected cells. Here we demonstrate that the invasion of polarized cells is a highly cooperative activity. Using a novel live-cell imaging approach, we visualized the cooperative entry of multiple bacteria into ruffles induced on the apical surfaces of polarized cells. The induction of membrane ruffles by activity of Salmonella enables otherwise noninvasive mutant strains to enter polarized host cells. Bacterial motility and chemotaxis were of lower importance for cooperativity in polarized-cell invasion. We propose that cooperative invasion is a key factor for the very efficient entry into polarized cells and a factor contributing to epithelial damage and intestinal inflammation. PMID:24711567

  17. Spatial Segregation of Virulence Gene Expression during Acute Enteric Infection with Salmonella enterica serovar Typhimurium

    PubMed Central

    Laughlin, Richard C.; Knodler, Leigh A.; Barhoumi, Roula; Payne, H. Ross; Wu, Jing; Gomez, Gabriel; Pugh, Roberta; Lawhon, Sara D.; Bäumler, Andreas J.; Steele-Mortimer, Olivia; Adams, L. Garry

    2014-01-01

    ABSTRACT To establish a replicative niche during its infectious cycle between the intestinal lumen and tissue, the enteric pathogen Salmonella enterica serovar Typhimurium requires numerous virulence genes, including genes for two type III secretion systems (T3SS) and their cognate effectors. To better understand the host-pathogen relationship, including early infection dynamics and induction kinetics of the bacterial virulence program in the context of a natural host, we monitored the subcellular localization and temporal expression of T3SS-1 and T3SS-2 using fluorescent single-cell reporters in a bovine, ligated ileal loop model of infection. We observed that the majority of bacteria at 2 h postinfection are flagellated, express T3SS-1 but not T3SS-2, and are associated with the epithelium or with extruding enterocytes. In epithelial cells, S. Typhimurium cells were surrounded by intact vacuolar membranes or present within membrane-compromised vacuoles that typically contained numerous vesicular structures. By 8 h postinfection, T3SS-2-expressing bacteria were detected in the lamina propria and in the underlying mucosa, while T3SS-1-expressing bacteria were in the lumen. Our work identifies for the first time the temporal and spatial regulation of T3SS-1 and -2 expression during an enteric infection in a natural host and provides further support for the concept of cytosolic S. Typhimurium in extruding epithelium as a mechanism for reseeding the lumen. PMID:24496791

  18. Genetic and phenotypic evidence of the Salmonella enterica serotype Enteritidis human-animal interface in Chile

    PubMed Central

    Retamal, Patricio; Fresno, Marcela; Dougnac, Catherine; Gutierrez, Sindy; Gornall, Vanessa; Vidal, Roberto; Vernal, Rolando; Pujol, Myriam; Barreto, Marlen; González-Acuña, Daniel; Abalos, Pedro

    2015-01-01

    Salmonella enterica serotype Enteritidis is a worldwide zoonotic agent that has been recognized as a very important food-borne bacterial pathogen, mainly associated with consumption of poultry products. The aim of this work was to determine genotypic and phenotypic evidence of S. Enteritidis transmission among seabirds, poultry and humans in Chile. Genotyping was performed using PCR-based virulotyping, pulse-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Pathogenicity-associated phenotypes were determined with survival to free radicals, acidic pH, starvation, antimicrobial resistance, and survival within human dendritic cells. As result of PCR and PFGE assays, some isolates from the three hosts showed identical genotypic patterns, and through MLST it was determined that all of them belong to sequence type 11. Phenotypic assays show diversity of bacterial responses among isolates. When results were analyzed according to bacterial host, statistical differences were identified in starvation and dendritic cells survival assays. In addition, isolates from seabirds showed the highest rates of resistance to gentamycin, tetracycline, and ampicillin. Overall, the very close genetic and phenotypic traits shown by isolates from humans, poultry, and seabirds suggest the inter-species transmission of S. Enteritidis bacteria between hosts, likely through anthropogenic environmental contamination that determines infection of seabirds with bacteria that are potentially pathogenic for other susceptible organism, including humans. PMID:26029196

  19. Evaluation of nisin-β-lactam antibiotics against clinical strains of Salmonella enterica serovar Typhi.

    PubMed

    Rishi, Praveen; Preet Singh, Aman; Garg, Neha; Rishi, Madhuri

    2014-12-01

    There is an imperative need to discover novel antimicrobials and anti-infective agents and build up innovative strategies to combat multidrug-resistant Salmonella. In this context, we had earlier confirmed that nisin has the potential to act in conjunction with β-lactams against murine salmonellosis using standard strain. However, evaluation of efficacy of these combinations against clinical isolates of Salmonella could be the next key step to confirm the value added potential of this peptide. The present study was therefore planned to validate the synergistic effects of nisin-β-lactams combinations against clinical isolates of Salmonella enterica serovar Typhi. MICs of the selected β-lactams, EDTA and nisin were determined by micro and macro broth dilution assays. In-vitro synergism between the agents was evaluated by fractional inhibitory concentration (FIC) index (checkerboard test) and time-kill assay. All the tested combinations showed synergy against the tested clinical strains except three, as evident by FIC index (checkerboard test) and time-kill assay. Especially, nisin-ceftriaxone and nisin-cefotaxime combinations demonstrated excellent synergistic activity. In view of the encouraging results obtained from the previous and present study, further studies need to be carried out using large number of strains from different regions to take into account the clinical variability of the strains. Though it is a simple study but highlights an important point about the possibility of using the said combination while making strategies to develop newer formulations. PMID:24961707

  20. Salmonella enterica Serovar Typhimurium Exploits Inflammation to Modify Swine Intestinal Microbiota

    PubMed Central

    Drumo, Rosanna; Pesciaroli, Michele; Ruggeri, Jessica; Tarantino, Michela; Chirullo, Barbara; Pistoia, Claudia; Petrucci, Paola; Martinelli, Nicola; Moscati, Livia; Manuali, Elisabetta; Pavone, Silvia; Picciolini, Matteo; Ammendola, Serena; Gabai, Gianfranco; Battistoni, Andrea; Pezzotti, Giovanni; Alborali, Giovanni L.; Napolioni, Valerio; Pasquali, Paolo; Magistrali, Chiara F.

    2016-01-01

    Salmonella enterica serovar Typhimurium is an important zoonotic gastrointestinal pathogen responsible for foodborne disease worldwide. It is a successful enteric pathogen because it has developed virulence strategies allowing it to survive in a highly inflamed intestinal environment exploiting inflammation to overcome colonization resistance provided by intestinal microbiota. In this study, we used piglets featuring an intact microbiota, which naturally develop gastroenteritis, as model for salmonellosis. We compared the effects on the intestinal microbiota induced by a wild type and an attenuated S. Typhimurium in order to evaluate whether the modifications are correlated with the virulence of the strain. This study showed that Salmonella alters microbiota in a virulence-dependent manner. We found that the wild type S. Typhimurium induced inflammation and a reduction of specific protecting microbiota species (SCFA-producing bacteria) normally involved in providing a barrier against pathogens. Both these effects could contribute to impair colonization resistance, increasing the host susceptibility to wild type S. Typhimurium colonization. In contrast, the attenuated S. Typhimurium, which is characterized by a reduced ability to colonize the intestine, and by a very mild inflammatory response, was unable to successfully sustain competition with the microbiota. PMID:26835435

  1. Proteomes of Host Cell Membranes Modified by Intracellular Activities of Salmonella enterica*

    PubMed Central

    Vorwerk, Stephanie; Krieger, Viktoria; Deiwick, Jörg; Hensel, Michael; Hansmeier, Nicole

    2015-01-01

    Intracellular pathogens need to establish a growth-stimulating host niche for survival and replication. A unique feature of the gastrointestinal pathogen Salmonella enterica serovar Typhimurium is the creation of extensive membrane networks within its host. An understanding of the origin and function of these membranes is crucial for the development of new treatment strategies. However, the characterization of this compartment is very challenging, and only fragmentary knowledge of its composition and biogenesis exists. Here, we describe a new proteome-based approach to enrich and characterize Salmonella-modified membranes. Using a Salmonella mutant strain that does not form this unique membrane network as a reference, we identified a high-confidence set of host proteins associated with Salmonella-modified membranes. This comprehensive analysis allowed us to reconstruct the interactions of Salmonella with host membranes. For example, we noted that Salmonella redirects endoplasmic reticulum (ER) membrane trafficking to its intracellular niche, a finding that has not been described for Salmonella previously. Our system-wide approach therefore has the potential to rapidly close gaps in our knowledge of the infection process of intracellular pathogens and demonstrates a hitherto unrecognized complexity in the formation of Salmonella host niches. PMID:25348832

  2. Regulation and production of Tcf, a cable-like fimbriae from Salmonella enterica serovar Typhi.

    PubMed

    Leclerc, Jean-Mathieu; Quevillon, Eve-Lyne; Houde, Yoan; Paranjape, Kiran; Dozois, Charles M; Daigle, France

    2016-05-01

    tcf (Typhi colonization factor) is one of the 12 putative chaperone/usher fimbrial clusters present in the Salmonella enterica serovar Typhi genome. We investigated the production, expression and regulation of tcf as well as its role during interaction with human cells. The tcf gene cluster was cloned and induced in Escherichia coli and S. Typhi, and the production of intertwined fibres similar to the Cbl (cable) pili of Burkholderia cepacia was observed on the bacterial surface by electron microscopy. In S. Typhi, tcf was expressed more after growth in M63 minimal medium than in standard Luria-Bertani medium. Analysis of the promoter region identified putative binding sites for the global regulators RcsB, ArgR and Fur. The expression of tcf was measured in isogenic strains lacking these global regulators. Under the conditions tested, the results showed that tcf expression was higher in the fur mutant and was regulated by iron concentration. Fur may regulate these fimbriae indirectly via the small RNAs RyhB1 and RyhB2. An isogenic mutant harbouring a deletion of the tcf cluster did not demonstrate any defect in adhesion or invasion of human epithelial cells, or in phagocytosis or survival in macrophages, when compared to the WT serovar Typhi strain. However, the tcf cluster contributed to adherence to human epithelial cells when introduced into E. coli. Thus, tcf genes encode functional fimbriae that can act as an adhesin and may contribute to colonization during typhoid fever. PMID:26944792

  3. Global Transcriptome and Mutagenic Analyses of the Acid Tolerance Response of Salmonella enterica Serovar Typhimurium

    PubMed Central

    Ryan, Daniel; Pati, Niladri Bhusan; Ojha, Urmesh K.; Padhi, Chandrashekhar; Ray, Shilpa; Jaiswal, Sangeeta; Singh, Gajinder P.; Mannala, Gopala K.; Schultze, Tilman; Chakraborty, Trinad

    2015-01-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the leading causative agents of food-borne bacterial gastroenteritis. Swift invasion through the intestinal tract and successful establishment in systemic organs are associated with the adaptability of S. Typhimurium to different stress environments. Low-pH stress serves as one of the first lines of defense in mammalian hosts, which S. Typhimurium must efficiently overcome to establish an infection. Therefore, a better understanding of the molecular mechanisms underlying the adaptability of S. Typhimurium to acid stress is highly relevant. In this study, we have performed a transcriptome analysis of S. Typhimurium under the acid tolerance response (ATR) and found a large number of genes (∼47%) to be differentially expressed (more than 1.5-fold or less than −1.5-fold; P < 0.01). Functional annotation revealed differentially expressed genes to be associated with regulation, metabolism, transport and binding, pathogenesis, and motility. Additionally, our knockout analysis of a subset of differentially regulated genes facilitated the identification of proteins that contribute to S. Typhimurium ATR and virulence. Mutants lacking genes encoding the K+ binding and transport protein KdpA, hypothetical protein YciG, the flagellar hook cap protein FlgD, and the nitrate reductase subunit NarZ were significantly deficient in their ATRs and displayed varied in vitro virulence characteristics. This study offers greater insight into the transcriptome changes of S. Typhimurium under the ATR and provides a framework for further research on the subject. PMID:26386064

  4. Organically managed soils reduce internal colonization of tomato plants by Salmonella enterica serovar Typhimurium.

    PubMed

    Gu, Ganyu; Cevallos-Cevallos, Juan M; Vallad, Gary E; van Bruggen, Ariena H C

    2013-04-01

    A two-phase experiment was conducted twice to investigate the effects of soil management on movement of Salmonella enterica Typhimurium in tomato plants. In the first phase, individual leaflets of 84 tomato plants grown in conventional or organic soils were dip inoculated two to four times before fruiting with either of two Salmonella Typhimurium strains (10(9) CFU/ml; 0.025% [vol/vol] Silwet L-77). Inoculated and adjacent leaflets were tested for Salmonella spp. densities for 30 days after each inoculation. Endophytic bacterial communities were characterized by polymerase chain reaction denaturing gradient gel electrophoresis before and after inoculation. Fruit and seed were examined for Salmonella spp. incidence. In phase 2, extracted seed were planted in conventional soil, and contamination of leaves and fruit of the second generation was checked. More Salmonella spp. survived in inoculated leaves on plants grown in conventional than in organic soil. The soil management effect on Salmonella spp. survival was confirmed for tomato plants grown in two additional pairs of soils. Endophytic bacterial diversities of tomato plants grown in conventional soils were significantly lower than those in organic soils. All contaminated fruit (1%) were from tomato plants grown in conventional soil. Approximately 5% of the seed from infested fruit were internally contaminated. No Salmonella sp. was detected in plants grown from contaminated seed. PMID:23506364

  5. Emergence of clinical Salmonella enterica serovar Typhimurium isolates with concurrent resistance to ciprofloxacin, ceftriaxone, and azithromycin.

    PubMed

    Wong, Marcus Ho Yin; Yan, Meiying; Chan, Edward Wai Chi; Biao, Kan; Chen, Sheng

    2014-07-01

    Salmonella infection is an important public health issue for which the needs of antimicrobial treatment are increasing. A total of 546 human clinical S. enterica serovar Typhimurium isolates were recovered from patients in hospitals in China during the period of 2005 to ∼ 2011. Twenty percent of the isolates exhibited resistance to ciprofloxacin, and 4% were resistant to ceftriaxone. Importantly, for the first time, 12 (2%) S. Typhimurium isolates resistant to both ciprofloxacin and ceftriaxone were recovered; among these 12 isolates, two were also resistant to azithromycin, and one was resistant to all other drugs tested. The combined effects of various transferrable extended-spectrum β-lactamase determinants and a novel efflux-based ciprofloxacin resistance mechanism encoded by the mobile efflux gene oqxAB were responsible for the emergence of these extremely (highly) drug-resistant (XDR) S. Typhimurium isolates. The dissemination of resistance genes, such as those encoding ESBLs and the OqxAB pump, among Salmonella organisms will speed up the selection of XDR Salmonella, posing a huge threat to public health and Salmonella infection control. PMID:24752251

  6. Cellular requirements for systemic control of Salmonella enterica serovar Typhimurium infections in mice.

    PubMed

    Kupz, Andreas; Bedoui, Sammy; Strugnell, Richard A

    2014-12-01

    The rational design of vaccines requires an understanding of the contributions of individual immune cell subsets to immunity. With this understanding, targeted vaccine delivery approaches and adjuvants can be developed to maximize vaccine efficiency and to minimize side effects (S. H. E. Kaufmann et al., Immunity 33:555-577, 2010; T. Ben-Yedidia and R. Arnon, Hum. Vaccines 1:95-101, 2005). We have addressed the contributions of different immune cell subsets and their ability to contribute to the control and clearance of the facultative intracellular pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) in a murine model. Using a systematic and reproducible model of experimental attenuated S. Typhimurium infection, we show that distinct lymphocyte deficiencies lead to one of four different infection outcomes: clearance, chronic infection, early death, or late death. Our study demonstrates a high level of functional redundancy in the ability of different lymphocyte subsets to provide interferon gamma (IFN-γ), a critical cytokine in Salmonella immunity. Whereas early control of the infection was entirely dependent on IFN-γ but not on any particular lymphocyte subset, clearance of the infection critically required CD4(+) T cells but appeared to be independent of IFN-γ. These data reinforce the idea of a bimodal immune response against Salmonella: an early T cell-independent but IFN-γ-dependent phase and a late T cell-dependent phase that may be IFN-γ independent. PMID:25225248

  7. Licoflavonol is an inhibitor of the type three secretion system of Salmonella enterica serovar Typhimurium.

    PubMed

    Guo, Zhixing; Li, Xiaoli; Li, Jianfang; Yang, Xuefei; Zhou, Yuan; Lu, Chunhua; Shen, Yuemao

    2016-09-01

    As an important food-borne human pathogen, Salmonella enterica serovar Typhimurium depends on its type III secretion system (T3SS) as a major virulence factor to cause disease all over the world. The T3SS secretes effector proteins to facilitate invasion into host cells. In this study, twenty prenylated flavonoids (1-20) were screened for their anti-T3SS activity, revealing that several analogs exhibited strong inhibitory effects on the secretion of Salmonella pathogenicity island 1 (SPI-1)-associated effector proteins without affecting the growth of bacteria and the secretion of the flagellar protein FliC. Among the flavonoids 1-20, licoflavonol (20) exhibited a strong inhibitory effect on the secretion of the SPI-1 effector proteins via regulating the transcription of the SicA/InvF genes, and the transportation of the effector protein SipC. In summary, licoflavonol, a novel natural inhibitor of Salmonella T3SS, could be a promising candidate for novel type of anti-virulence drugs. PMID:27387231

  8. Solvent accessibility and purifying selection within proteins of Escherichia coli and Salmonella enterica.

    PubMed

    Bustamante, C D; Townsend, J P; Hartl, D L

    2000-02-01

    The neutral theory of molecular evolution predicts that variation within species is inversely related to the strength of purifying selection, but the strength of purifying selection itself must be related to physical constraints imposed by protein folding and function. In this paper, we analyzed five enzymes for which polymorphic sequence variation within Escherichia coli and/or Salmonella enterica was available, along with a protein structure. Single and multivariate logistic regression models are presented that evaluate amino acid size, physicochemical properties, solvent accessibility, and secondary structure as predictors of polymorphism. A model that contains a positive coefficient of association between polymorphism and solvent accessibility and separate intercepts for each secondary-structure element is sufficient to explain the observed variation in polymorphism between sites. The model predicts an increase in the probability of amino acid polymorphism with increasing solvent accessibility for each protein regardless of physicochemical properties, secondary-structure element, or size of the amino acid. This result, when compared with the distribution of synonymous polymorphism, which shows no association with solvent accessibility, suggests a strong decrease in purifying selection with increasing solvent accessibility. PMID:10677853

  9. Bistable Expression of CsgD in Salmonella enterica Serovar Typhimurium Connects Virulence to Persistence

    PubMed Central

    MacKenzie, Keith D.; Wang, Yejun; Shivak, Dylan J.; Wong, Cynthia S.; Hoffman, Leia J. L.; Lam, Shirley; Kröger, Carsten; Cameron, Andrew D. S.; Townsend, Hugh G. G.; Köster, Wolfgang

    2015-01-01

    Pathogenic bacteria often need to survive in the host and the environment, and it is not well understood how cells transition between these equally challenging situations. For the human and animal pathogen Salmonella enterica serovar Typhimurium, biofilm formation is correlated with persistence outside a host, but the connection to virulence is unknown. In this study, we analyzed multicellular-aggregate and planktonic-cell subpopulations that coexist when S. Typhimurium is grown under biofilm-inducing conditions. These cell types arise due to bistable expression of CsgD, the central biofilm regulator. Despite being exposed to the same stresses, the two cell subpopulations had 1,856 genes that were differentially expressed, as determined by transcriptome sequencing (RNA-seq). Aggregated cells displayed the characteristic gene expression of biofilms, whereas planktonic cells had enhanced expression of numerous virulence genes. Increased type three secretion synthesis in planktonic cells correlated with enhanced invasion of a human intestinal cell line and significantly increased virulence in mice compared to the aggregates. However, when the same groups of cells were exposed to desiccation, the aggregates survived better, and the competitive advantage of planktonic cells was lost. We hypothesize that CsgD-based differentiation is a form of bet hedging, with single cells primed for host cell invasion and aggregated cells adapted for persistence in the environment. This allows S. Typhimurium to spread the risks of transmission and ensures a smooth transition between the host and the environment. PMID:25824832

  10. RosE represses Std fimbrial expression in Salmonella enterica serotype Typhimurium

    PubMed Central

    Chessa, Daniela; Winter, Maria G; Nuccio, Sean-Paul; Tükel, Çagla; Bäumler, Andreas J

    2008-01-01

    The Salmonella enterica serotype Typhimurium (S. typhimurium) genome contains a large repertoire of putative fimbrial operons that remain poorly characterized because they are not expressed in vitro. In this study, insertions that induced expression of the putative stdABCD fimbrial operon were identified from a random bank of transposon mutants by screening with immuno-magnetic particles for ligand expression (SIMPLE). Transposon insertions upstream of csgC and lrhA or within dam, setB and STM4463 (renamed rosE) resulted in expression of StdA and its assembly into fimbrial filaments on the cell surface. RosE is a novel negative regulator of Std fimbrial expression as indicated by its repression of a std::lacZ reporter construct and by binding of the purified protein to a DNA region upstream of the stdA start codon. Expression of Std fimbriae in the rosE mutant resulted in increased attachment of S. typhimurium to human colonic epithelial cell lines (T-84 and CaCo-2). A rosE mutant exhibited a reduced ability to compete with virulent S. typhimurium for colonization of murine organs, while no defect was observed when both competing strains carried a stdAB deletion. These data suggest that a tight control of Std fimbrial expression mediated by RosE is required during host pathogen interaction. PMID:18331470

  11. Osteomyelitis due to Salmonella enterica subsp. arizonae: the price of exotic pets.

    PubMed

    Kolker, S; Itsekzon, T; Yinnon, A M; Lachish, T

    2012-02-01

    We describe a 31-year-old immunocompromised patient who developed sepsis and osteomyelitis due to Salmonella enterica subsp. arizonae secondary to exposure to iguana and snakes kept as pets at her home, and review all 23 previously published cases of bone and joint infections due to this organism, for a total of nine children and 15 adults. Eleven of the adults were female (73%), compared with three (33%) of the children (p <0.01). Significant underlying illnesses were present in all 15 adults and in five children (55%, p <0.05); 10 (77%) of the adults were immunosuppressed, compared with one child only (17%) (p <0.05). In ten of the adults the knee was infected (67%), compared with one child only (11%, p <0.01). Antibiotic therapy was prolonged in both adults and children, and in most cases consisted of 4-6 weeks of parenteral treatment. Complete cure and survival was attained in 11 of 15 adults (73%) and all nine children (NS). Optimal antibiotic treatment probably consists of ceftriaxone or a fluoroquinolone, if the organism is susceptible. PMID:21745257

  12. Characterization of the ELPhiS prophage from Salmonella enterica serovar Enteritidis strain LK5.

    PubMed

    Hanna, L Farris; Matthews, T David; Dinsdale, Elizabeth A; Hasty, David; Edwards, Robert A

    2012-03-01

    Phages are a primary driving force behind the evolution of bacterial pathogens by transferring a variety of virulence genes into their hosts. Similar to other bacterial genomes, the Salmonella enterica serovar Enteritidis LK5 genome contains several regions that are homologous to phages. Although genomic analysis demonstrated the presence of prophages, it was unable to confirm which phage elements within the genome were viable. Genetic markers were used to tag one of the prophages in the genome to allow monitoring of phage induction. Commonly used laboratory strains of Salmonella were resistant to phage infection, and therefore a rapid screen was developed to identify susceptible hosts. This approach showed that a genetically tagged prophage, ELPhiS (Enteritidis lysogenic phage S), was capable of infecting Salmonella serovars that are diverse in host range and virulence and has the potential to laterally transfer genes between these serovars via lysogenic conversion. The rapid screen approach is adaptable to any system with a large collection of isolates and may be used to test the viability of prophages found by sequencing the genomes of various bacterial pathogens. PMID:22247173

  13. Identification of potential drug targets in Salmonella enterica sv. Typhimurium using metabolic modelling and experimental validation.

    PubMed

    Hartman, Hassan B; Fell, David A; Rossell, Sergio; Jensen, Peter Ruhdal; Woodward, Martin J; Thorndahl, Lotte; Jelsbak, Lotte; Olsen, John Elmerdahl; Raghunathan, Anu; Daefler, Simon; Poolman, Mark G

    2014-06-01

    Salmonella enterica sv. Typhimurium is an established model organism for Gram-negative, intracellular pathogens. Owing to the rapid spread of resistance to antibiotics among this group of pathogens, new approaches to identify suitable target proteins are required. Based on the genome sequence of S. Typhimurium and associated databases, a genome-scale metabolic model was constructed. Output was based on an experimental determination of the biomass of Salmonella when growing in glucose minimal medium. Linear programming was used to simulate variations in the energy demand while growing in glucose minimal medium. By grouping reactions with similar flux responses, a subnetwork of 34 reactions responding to this variation was identified (the catabolic core). This network was used to identify sets of one and two reactions that when removed from the genome-scale model interfered with energy and biomass generation. Eleven such sets were found to be essential for the production of biomass precursors. Experimental investigation of seven of these showed that knockouts of the associated genes resulted in attenuated growth for four pairs of reactions, whilst three single reactions were shown to be essential for growth. PMID:24777662

  14. Escherichia coli O157:H7 Induces Stronger Plant Immunity than Salmonella enterica Typhimurium SL1344

    PubMed Central

    Roy, Debanjana; Panchal, Shweta; Rosa, Bruce A

    2014-01-01

    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 triggered stomatal closure even under high relative humidity (RH); an environmental condition that generally weakens plant defenses against bacteria in the field and laboratory conditions. SL1344 instead induced a transient stomatal immunity. We also observed that PR1 gene expression was significantly higher in Arabidopsis leaves infected with O157:H7 as compared to SL1344. These results suggest that plants may recognize and respond to some human pathogens more effectively than others. Furthermore, stomatal immunity can diminish the penetration of human pathogens through the leaf epidermis resulting in low bacterial titers in the plant apoplast suggesting that additional control measures can be employed to prevent food contamination. The understanding of how plant responses can diminish bacterial contamination is paramount in preventing outbreaks and improving the safety of food supplies. PMID:23301812

  15. Diguanylate Cyclases AdrA and STM1987 Regulate Salmonella enterica Exopolysaccharide Production during Plant Colonization in an Environment-Dependent Manner

    PubMed Central

    Cowles, Kimberly N.; Willis, David K.; Engel, Tyler N.; Jones, Jeffrey B.

    2015-01-01

    Increasing evidence indicates that despite exposure to harsh environmental stresses, Salmonella enterica successfully persists on plants, utilizing fresh produce as a vector to animal hosts. Among the important S. enterica plant colonization factors are those involved in biofilm formation. S. enterica biofilm formation is controlled by the signaling molecule cyclic di-GMP and represents a sessile lifestyle on surfaces that protects the bacterium from environmental factors. Thus, the transition from a motile, planktonic lifestyle to a sessile lifestyle may represent a vital step in bacterial success. This study examined the mechanisms of S. enterica plant colonization, including the role of diguanylate cyclases (DGCs) and phosphodiesterases (PDEs), the enzymes involved in cyclic di-GMP metabolism. We found that two biofilm components, cellulose and curli, are differentially required at distinct stages in root colonization and that the DGC STM1987 regulates cellulose production in this environment independent of AdrA, the DGC that controls the majority of in vitro cellulose production. In addition, we identified a new function for AdrA in the transcriptional regulation of colanic acid and demonstrated that adrA and colanic acid biosynthesis are associated with S. enterica desiccation tolerance on the leaf surface. Finally, two PDEs with known roles in motility, STM1344 and STM1697, had competitive defects in the phyllosphere, suggesting that regulation of motility is crucial for S. enterica survival in this niche. Our results indicate that specific conditions influence the contribution of individual DGCs and PDEs to bacterial success, perhaps reflective of differential responses to environmental stimuli. PMID:26655751

  16. Genes ycfR, sirA and yigG Contribute to the Surface Attachment of Salmonella enterica Typhimurium and Saintpaul to Fresh Produce

    PubMed Central

    Salazar, Joelle K.; Deng, Kaiping; Tortorello, Mary Lou; Brandl, Maria T.; Wang, Hui; Zhang, Wei

    2013-01-01

    Salmonella enterica is a frequent contaminant of minimally-processed fresh produce linked to major foodborne disease outbreaks. The molecular mechanisms underlying the association of this enteric pathogen with fresh produce remain largely unexplored. In our recent study, we showed that the expression of a putative stress regulatory gene, ycfR, was significantly induced in S. enterica upon exposure to chlorine treatment, a common industrial practice for washing and decontaminating fresh produce during minimal processing. Two additional genes, sirA involved in S. enterica biofilm formation and yigG of unknown function, were also found to be differentially regulated under chlorine stress. To further characterize the roles of ycfR, sirA, and yigG in S. enterica attachment and survival on fresh produce, we constructed in-frame deletions of all three genes in two different S. enterica serovars, Typhimurium and Saintpaul, which have been implicated in previous disease outbreaks linked to fresh produce. Bacterial attachment to glass and polystyrene microtiter plates, cell aggregation and hydrophobicity, chlorine resistance, and surface attachment to intact spinach leaf and grape tomato were compared among wild-type strains, single-gene deletion mutants, and their respective complementation mutants. The results showed that deletions of ycfR, sirA, and yigG reduced bacterial attachment to glass and polystyrene as well as fresh produce surface with or without chlorine treatment in both Typhimurium and Saintpaul. Deletion of ycfR in Typhimurium significantly reduced bacterial chlorine resistance and the attachment to the plant surfaces after chlorinated water washes. Deletions of ycfR in Typhimurium and yigG in Saintpaul resulted in significant increase in cell aggregation. Our findings suggest that ycfR, sirA, and yigG collectively contribute to S. enterica surface attachment and survival during post-harvest minimal processing of fresh produce. PMID:23451197

  17. Genes ycfR, sirA and yigG contribute to the surface attachment of Salmonella enterica Typhimurium and Saintpaul to fresh produce.

    PubMed

    Salazar, Joelle K; Deng, Kaiping; Tortorello, Mary Lou; Brandl, Maria T; Wang, Hui; Zhang, Wei

    2013-01-01

    Salmonella enterica is a frequent contaminant of minimally-processed fresh produce linked to major foodborne disease outbreaks. The molecular mechanisms underlying the association of this enteric pathogen with fresh produce remain largely unexplored. In our recent study, we showed that the expression of a putative stress regulatory gene, ycfR, was significantly induced in S. enterica upon exposure to chlorine treatment, a common industrial practice for washing and decontaminating fresh produce during minimal processing. Two additional genes, sirA involved in S. enterica biofilm formation and yigG of unknown function, were also found to be differentially regulated under chlorine stress. To further characterize the roles of ycfR, sirA, and yigG in S. enterica attachment and survival on fresh produce, we constructed in-frame deletions of all three genes in two different S. enterica serovars, Typhimurium and Saintpaul, which have been implicated in previous disease outbreaks linked to fresh produce. Bacterial attachment to glass and polystyrene microtiter plates, cell aggregation and hydrophobicity, chlorine resistance, and surface attachment to intact spinach leaf and grape tomato were compared among wild-type strains, single-gene deletion mutants, and their respective complementation mutants. The results showed that deletions of ycfR, sirA, and yigG reduced bacterial attachment to glass and polystyrene as well as fresh produce surface with or without chlorine treatment in both Typhimurium and Saintpaul. Deletion of ycfR in Typhimurium significantly reduced bacterial chlorine resistance and the attachment to the plant surfaces after chlorinated water washes. Deletions of ycfR in Typhimurium and yigG in Saintpaul resulted in significant increase in cell aggregation. Our findings suggest that ycfR, sirA, and yigG collectively contribute to S. enterica surface attachment and survival during post-harvest minimal processing of fresh produce. PMID:23451197

  18. Analysis of plasmid-mediated quinolone and oxyimino-cephalosporin resistance mechanisms in Uruguayan Salmonella enterica isolates from 2011-2013.

    PubMed

    Cordeiro, Nicolás F; Nabón, Adriana; García-Fulgueiras, Virginia; Álvez, Marcelo; Sirok, Alfredo; Camou, Teresa; Vignoli, Rafael

    2016-09-01

    This study characterised the mechanisms of fluoroquinolone and oxyimino-cephalosporin resistance in human Salmonella enterica isolates in Uruguay. Salmonella enterica isolates were collected from 2011-2013 and were selected based on non-susceptibility to ciprofloxacin and/or oxyimino-cephalosporins. The disk diffusion assay was performed for various antibiotics, and the ciprofloxacin minimum inhibitory concentration (MIC) was determined following CLSI guidelines. Genetic relatedness was determined following PulseNet protocols. Extended-spectrum β-lactamases, ampC alleles and plasmid-mediated quinolone resistance were characterised by PCR and sequencing. Plasmid analyses were carried out by conjugation or transformation assays, and plasmid-encoded genes were identified by PCR. Mutations in the quinolone resistance-determining region of gyrases were sought by PCR and sequencing. Among 579 isolates, 105 (18.4%) ciprofloxacin-non-susceptible (CIP-NS) isolates, 9 (1.6%) oxyimino-cephalosporin-resistant isolates and 2 (0.3%) isolates resistant to both antibiotic families were detected. Thirteen isolates carried qnrB alleles (twelve qnrB19 and one qnrB2), four carried blaCTX-M-8, two blaCTX-M-14, two blaSHV-2 and three blaCMY-2-like genes. No correlation was found between mutations in gyrases and ciprofloxacin MICs. Several co-circulating clones of S. enterica ssp. enterica serovar Typhimurium were detected; conversely, S. enterica ssp. enterica serovar Enteritidis corresponded mainly to a single circulating clone. Nine (75%) of twelve of CIP-NS extraintestinal isolates shared the same pulsotype with intestinal isolates. During the study period, the frequency of CIP-NS isolates increased, albeit with ciprofloxacin MICs of 0.125-0.5mg/L. Detection of the same quinolone-resistant clones recovered both from intestinal and extraintestinal samples highlights the significance of epidemiological surveillance of antibiotic susceptibility for every human Salmonella isolate. PMID

  19. Interpretations of Antibody Responses to Salmonella enterica Serotype Enteritidis gm Flagellin in Poultry Flocks Are Enhanced by a Kinetics-Based Enzyme-Linked Immunosorbent Assay

    PubMed Central

    McDonough, Patrick L.; Jacobson, Richard H.; Timoney, John F.; Mutalib, Ahmed; Kradel, David C.; Chang, Yung-fu; Shin, Sang J.; Lein, Donald H.; Trock, Susan; Wheeler, Kaye

    1998-01-01

    Many regulatory and diagnostic programs for the detection of Salmonella enterica serotype Enteritidis infection in commercial poultry flocks have relied on rapid Pullorum agglutination tests to screen birds because of the shared antigens of S. enterica Enteritidis and S. enterica Pullorum and Gallinarum; however, the use of the enzyme-linked immunosorbent assay (ELISA) format affords better analytical sensitivity than crude agglutination tests. In this study, we adapted our earlier conventional indirect ELISA, using gm flagellin as the antigen, to a kinetics-based, computer-controlled ELISA (KELA). The KELA was used to screen for flagellin antibody from three commercial flocks: (i) a large flock involved in a U.S. Department of Agriculture trace back from a human S. enterica Enteritidis foodborne outbreak (n = 3,209), (ii) a flock infected with the endemic S. enterica Enteritidis serotype but which also had multiple other salmonella serotypes (n = 65), and (iii) an S. enterica Pullorum-infected flock (n = 12). The first flock (S. enterica Enteritidis prevalence of 2.45% based on culture) provided a field test of the KELA and allowed the calculation of diagnostic sensitivity (D-Sn) and diagnostic specificity (D-Sp). With a cutoff of 10 (used for screening flocks [i.e., high sensitivity]), the KELA has a D-Sn of 95.2% and a D-Sp of 18.5%; with a cutoff of 140 (used in confirmatory flock testing [i.e., high specificity]), the KELA has a D-Sn of 28.0% and a D-Sp of 99.1%. We found that with a cutoff of 60 (D-Sn = 63.1%; D-Sp = 91.6%), we could eliminate reactions in the KELA caused by other non-S. enterica Enteritidis salmonellae. The KELA was also compared to two commercial rapid Pullorum tests, the Solvay (D-Sn = 94.9%; D-Sp = 55.5%) and the Vineland (D-Sn = 62.0%; D-Sp = 75.3%). PMID:9665965

  20. High-throughput molecular determination of salmonella enterica serovars by use of multiplex PCR and capillary electrophoresis analysis.

    PubMed

    Leader, Brandon T; Frye, Jonathan G; Hu, Jinxin; Fedorka-Cray, Paula J; Boyle, David S

    2009-05-01

    Salmonella enterica is a leading cause of food-borne illness worldwide and is also a major cause of morbidity and mortality in domestic and wild animals. In the current study, a high-throughput molecular assay was developed to determine the most common clinical and nonhuman serovars of S. enterica in the United States. Sixteen genomic targets were identified based on their differential distribution among common serovars. Primers were designed to amplify regions of each of these targets in a single multiplex PCR while incorporating a 6-carboxyfluorescein-labeled universal primer to fluorescently label all amplicons. The fluorescently labeled PCR products were separated using capillary electrophoresis, and a Salmonella multiplex assay for rapid typing (SMART) code was generated for each isolate, based upon the presence or absence of PCR products generated from each target gene. Seven hundred fifty-one blind clinical isolates of Salmonella from Washington State, collected in 2007 and previously serotyped via antisera, were screened with the assay. A total of 89.6% of the isolates were correctly identified based on comparison to a panel of representative SMART codes previously determined for the top 50 most common serovars in the United States. Of the remaining isolates, 6.2% represented isolates that produced a new SMART code for a previously determined serotype, while the final 8.8% were from serotypes not screened in the original panel used to score isolates in the blinded study. This high-throughput multiplex PCR assay allowed simple and accurate typing of the most prevalent clinical serovars of Salmonella enterica at a level comparable to that of conventional serotyping, but at a fraction of both the cost and time required per test. PMID:19261787

  1. Occurrence of Antimicrobial-Resistant Escherichia coli and Salmonella enterica in the Beef Cattle Production and Processing Continuum.

    PubMed

    Schmidt, John W; Agga, Getahun E; Bosilevac, Joseph M; Brichta-Harhay, Dayna M; Shackelford, Steven D; Wang, Rong; Wheeler, Tommy L; Arthur, Terrance M

    2015-01-01

    Specific concerns have been raised that third-generation cephalosporin-resistant (3GC(r)) Escherichia coli, trimethoprim-sulfamethoxazole-resistant (COT(r)) E. coli, 3GC(r) Salmonella enterica, and nalidixic acid-resistant (NAL(r)) S. enterica may be present in cattle production environments, persist through beef processing, and contaminate final products. The prevalences and concentrations of these organisms were determined in feces and hides (at feedlot and processing plant), pre-evisceration carcasses, and final carcasses from three lots of fed cattle (n = 184). The prevalences and concentrations were further determined for strip loins from 103 of the carcasses. 3GC(r) Salmonella was detected on 7.6% of hides during processing and was not detected on the final carcasses or strip loins. NAL(r) S. enterica was detected on only one hide. 3GC(r) E. coli and COT(r) E. coli were detected on 100.0% of hides during processing. Concentrations of 3GC(r) E. coli and COT(r) E. coli on hides were correlated with pre-evisceration carcass contamination. 3GC(r) E. coli and COT(r) E. coli were each detected on only 0.5% of final carcasses and were not detected on strip loins. Five hundred and 42 isolates were screened for extraintestinal pathogenic E. coli (ExPEC) virulence-associated markers. Only two COT(r) E. coli isolates from hides were ExPEC, indicating that fed cattle products are not a significant source of ExPEC causing human urinary tract infections. The very low prevalences of these organisms on final carcasses and their absence on strip loins demonstrate that current sanitary dressing procedures and processing interventions are effective against antimicrobial-resistant bacteria. PMID:25398858

  2. Development and Evaluation of a Multiplex Real-Time Polymerase Chain Reaction Procedure to Clinically Type Prevalent Salmonella enterica Serovars

    PubMed Central

    Muñoz, Nélida; Diaz-Osorio, Miguel; Moreno, Jaime; Sánchez-Jiménez, Miryan; Cardona-Castro, Nora

    2010-01-01

    A multiplex real-time polymerase chain reaction procedure was developed to identify the most prevalent clinical isolates of Salmonella enterica subsp. enterica. Genes from the rfb, fliC, fljB, and viaB groups that encode the O, H, and Vi antigens were used to design 15 primer pairs and TaqMan probes specific for the genes rfbJ, wzx, fliC, fljB, wcdB, the sdf-l sequence, and invA, which was used as an internal amplification control. The primers and probes were variously combined into six sets. The first round of reactions used two of these sets to detect Salmonella O:4, O:9, O:7, O:8, and O:3,10 serogroups. Once the serogroups were identified, the results of a second round of reactions that used primers and probes for the flagellar antigen l genes, 1,2; e,h; g,m; d; e,n,x; and z10, and the Vi gene were used to identify individual serovars. The procedure was standardized using 18 Salmonella reference strains and other enterobacteria. The procedure's reliability and sensitivity was evaluated using 267 randomly chosen serotyped Salmonella clinical isolates. The procedure had a sensitivity of 95.5% and was 100% specific. Thus, our technique is a quick, sensitive, reliable, and specific means of identifying S. enterica serovars and can be used in conjunction with traditional serotyping. Other primer and probe combinations could be used to increase the number of identifiable serovars. PMID:20110454

  3. Trends in Serotype Distribution and Antimicrobial Susceptibility in Salmonella enterica Isolates from Humans in Belgium, 2009 to 2013

    PubMed Central

    Ceyssens, Pieter-Jan; Mattheus, Wesley; Vanhoof, Raymond

    2014-01-01

    The Belgian National Reference Centre for Salmonella received 16,544 human isolates of Salmonella enterica between January 2009 and December 2013. Although 377 different serotypes were identified, the landscape is dominated by S. enterica serovars Typhimurium (55%) and Enteritidis (19%) in a ratio which is inverse to European Union averages. With outbreaks of Salmonella serotypes Ohio, Stanley, and Paratyphi B variant Java as prime examples, 20 serotypes displayed significant fluctuations in this 5-year period. Typhoid strains account for 1.2% of Belgian salmonellosis cases. Large-scale antibiotic susceptibility analyses (n = 4,561; panel of 12 antibiotics) showed declining resistance levels in S. Enteritis and Typhimurium isolates for 8 and 3 tested agents, respectively. Despite low overall resistance to ciprofloxacin (4.4%) and cefotaxime (1.6%), we identified clonal lineages of Salmonella serotypes Kentucky and Infantis displaying rising resistance against these clinically important drugs. Quinolone resistance is mainly mediated by serotype-specific mutations in GyrA residues Ser83 and Asp87 (92.2% not wild type), while an additional ParC_Ser80Ile mutation leads to ciprofloxacin resistance in 95.5% S. Kentucky isolates, which exceeds European averages. Plasmid-mediated quinolone resistance (PMQR) alleles qnrA1 (n = 1), qnrS (n = 9), qnrD1 (n = 4), and qnrB (n = 4) were found in only 3.0% of 533 isolates resistant to nalidixic acid. In cefotaxime-resistant isolates, we identified a broad range of Ambler class A and C β-lactamase genes (e.g., blaSHV-12, blaTEM-52, blaCTX-M-14, and blaCTX-M-15) commonly associated with members of the family Enterobacteriaceae. In conclusion, resistance to fluoroquinolones and cefotaxime remains rare in human S. enterica, but clonal resistant serotypes arise, and continued (inter)national surveillance is mandatory to understand the origin and routes of dissemination thereof. PMID:25385108

  4. 2-Aminoacrylate Stress Induces a Context-Dependent Glycine Requirement in ridA Strains of Salmonella enterica

    PubMed Central

    Ernst, Dustin C.

    2015-01-01

    ABSTRACT The reactive enamine 2-aminoacrylate (2AA) is a metabolic stressor capable of damaging cellular components. Members of the broadly conserved Rid (RidA/YER057c/UK114) protein family mitigate 2AA stress in vivo by facilitating enamine and/or imine hydrolysis. Previous work showed that 2AA accumulation in ridA strains of Salmonella enterica led to the inactivation of multiple target enzymes, including serine hydroxymethyltransferase (GlyA). However, the specific cause of a ridA strain's inability to grow during periods of 2AA stress had yet to be determined. Work presented here shows that glycine supplementation suppressed all 2AA-dependent ridA strain growth defects described to date. Depending on the metabolic context, glycine appeared to suppress ridA strain growth defects by eliciting a GcvB small RNA-dependent regulatory response or by serving as a precursor to one-carbon units produced by the glycine cleavage complex (GCV). In either case, the data suggest that GlyA is the most physiologically sensitive target of 2AA inactivation in S. enterica. The universally conserved nature of GlyA among free-living organisms highlights the importance of RidA in mitigating 2AA stress. IMPORTANCE The RidA stress response prevents 2-aminoacrylate (2AA) damage from occurring in prokaryotes and eukaryotes alike. 2AA inactivation of serine hydroxymethyltransferase (GlyA) from Salmonella enterica restricts glycine and one-carbon production, ultimately reducing fitness of the organism. The cooccurrence of genes encoding 2AA production enzymes and serine hydroxy-methyltransferase (SHMT) in many genomes may in part underlie the evolutionary selection for Rid proteins to maintain appropriate glycine and one-carbon metabolism throughout life. PMID:26574511

  5. Evaluation of a simple blood culture amplification and antigen detection method for diagnosis of Salmonella enterica serovar typhi bacteremia.

    PubMed

    Castonguay-Vanier, Josée; Davong, Viengmon; Bouthasavong, Latsanyphone; Sengdetka, Davanh; Simmalavong, Manivone; Seupsavith, Amphayvanh; Dance, David A B; Baker, Stephen; Le Thi Phuong, Tu; Vongsouvath, Manivanh; Newton, Paul N

    2013-01-01

    In most areas where typhoid is endemic, laboratory diagnosis is not possible due to the lack of appropriate facilities. We investigated whether the combination of blood culture amplification of Salmonella enterica serovar Typhi with an S. Typhi antigen rapid diagnostic test (RDT) could be an accurate and inexpensive tool for the accelerated diagnosis of patients with acute typhoid in Laos. For a panel of 23 Gram-negative reference pathogens, the Standard Diagnostics (catalog no. 15FK20; Kyonggi-do, South Korea) RDT gave positive results for S. Typhi NCTC 8385, S. Typhi NCTC 786 (Vi negative), Salmonella enterica serovar Enteritidis (ATCC 13076), and Salmonella enterica serovar Ndolo NCTC 8700 (all group D). In a prospective study of 6,456 blood culture bottles from 3,028 patients over 15 months, 392 blood culture bottles (6.1%) from 221 (7.3%) patients had Gram-negative rods (GNRs) seen in the blood culture fluid. The sensitivity, negative predictive value, specificity, and positive predictive value were 96.7%, 99.5%, 97.9%, and 87.9%, respectively, for patients with proven S. Typhi bacteremia and 91.2%, 98.4%, 98.9%, and 93.9% for patients with group D Salmonella. The median (range) number of days between diagnosis by RDT and reference assays was 1 (-1 to +2) day for those with confirmed S. Typhi. The use of antigen-based pathogen detection in blood culture fluid may be a useful, relatively rapid, inexpensive, and accurate technique for the identification of important causes of bacteremia in the tropics. PMID:23100346

  6. CTX-M-27 Producing Salmonella enterica Serotypes Typhimurium and Indiana Are Prevalent among Food-Producing Animals in China

    PubMed Central

    Zhang, Wen-Hui; Lin, Xiang-Yan; Xu, Liang; Gu, Xi-Xi; Yang, Ling; Li, Wan; Ren, Si-Qi; Liu, Ya-Hong; Zeng, Zhen-Ling; Jiang, Hong-Xia

    2016-01-01

    Salmonella spp. is one of the most important food-borne pathogens causing digestive tract and invasive infections in both humans and animals. Extended-spectrum β-lactamases (ESBLs) especially the CTX-M-type ESBLs are increasingly being reported worldwide and in China. These studies seldom focused on Salmonella isolates from food-producing animals. The aim of this study was to characterize the antimicrobial resistance profiles, serotypes and ESBLs and in particular, CTX-M producing Salmonella isolates from chickens and pigs in China. Salmonella isolates were identified by API20E system and polymerase chain reaction (PCR) assay; serotypes were determined using slide agglutination with hyperimmune sera; antimicrobial susceptibility was tested using the ager dilution method; the prevalence of ESBLs and PMQR genes were screened by PCR; CTX-M-producing isolates were further characterized by conjugation along with genetic relatedness and plasmid replicon type. In total, 159 Salmonella strains were identified, among which 95 strains were Salmonella enterica serovar Typhimurium, 63 strains were S. enterica serovar Indiana, and 1 strain was S. enterica serovar Enteritidis. All of these isolates presented multi-drug resistant phenotypes. Forty-five isolates carried blaCTX-M genes, the most common subtype was CTX-M-27(34), followed by CTX-M-65(7) and CTX-M-14(4). Most blaCTX-M genes were transmitted by non-typeable or IncN/IncFIB/IncP/IncA/C/IncHI2 plasmids with sizes ranging from 80 to 280 kb. In particular, all the 14 non-typeable plasmids were carrying blaCTX-M-27 gene and had a similar size. PFGE profiles indicated that CTX-M-positive isolates were clonally related among the same serotype, whilst the isolates of different serotypes were genetically divergent. This suggested that both clonal spread of resistant strains and horizontal transmission of the resistance plasmids contributed to the dissemination of blaCTX-M-9G-positive Salmonella isolates. The presence and spread

  7. CTX-M-27 Producing Salmonella enterica Serotypes Typhimurium and Indiana Are Prevalent among Food-Producing Animals in China.

    PubMed

    Zhang, Wen-Hui; Lin, Xiang-Yan; Xu, Liang; Gu, Xi-Xi; Yang, Ling; Li, Wan; Ren, Si-Qi; Liu, Ya-Hong; Zeng, Zhen-Ling; Jiang, Hong-Xia

    2016-01-01

    Salmonella spp. is one of the most important food-borne pathogens causing digestive tract and invasive infections in both humans and animals. Extended-spectrum β-lactamases (ESBLs) especially the CTX-M-type ESBLs are increasingly being reported worldwide and in China. These studies seldom focused on Salmonella isolates from food-producing animals. The aim of this study was to characterize the antimicrobial resistance profiles, serotypes and ESBLs and in particular, CTX-M producing Salmonella isolates from chickens and pigs in China. Salmonella isolates were identified by API20E system and polymerase chain reaction (PCR) assay; serotypes were determined using slide agglutination with hyperimmune sera; antimicrobial susceptibility was tested using the ager dilution method; the prevalence of ESBLs and PMQR genes were screened by PCR; CTX-M-producing isolates were further characterized by conjugation along with genetic relatedness and plasmid replicon type. In total, 159 Salmonella strains were identified, among which 95 strains were Salmonella enterica serovar Typhimurium, 63 strains were S. enterica serovar Indiana, and 1 strain was S. enterica serovar Enteritidis. All of these isolates presented multi-drug resistant phenotypes. Forty-five isolates carried bla CTX-M genes, the most common subtype was CTX-M-27(34), followed by CTX-M-65(7) and CTX-M-14(4). Most bla CTX-M genes were transmitted by non-typeable or IncN/IncFIB/IncP/IncA/C/IncHI2 plasmids with sizes ranging from 80 to 280 kb. In particular, all the 14 non-typeable plasmids were carrying bla CTX-M-27 gene and had a similar size. PFGE profiles indicated that CTX-M-positive isolates were clonally related among the same serotype, whilst the isolates of different serotypes were genetically divergent. This suggested that both clonal spread of resistant strains and horizontal transmission of the resistance plasmids contributed to the dissemination of bla CTX-M-9G-positive Salmonella isolates. The presence and

  8. Highly Drug-Resistant Salmonella enterica Serovar Indiana Clinical Isolates Recovered from Broilers and Poultry Workers with Diarrhea in China.

    PubMed

    Gong, Jiansen; Wang, Chengming; Shi, Shourong; Bao, Hongduo; Zhu, Chunhong; Kelly, Patrick; Zhuang, Linlin; Lu, Guangwu; Dou, Xinhong; Wang, Ran; Xu, Bu; Zou, Jianmin

    2016-03-01

    Highly drug-resistant Salmonella enterica serovar Indiana became the most common serovar in broilers with diarrhea in China over the course of this study (15% in 2010 to 70% in 2014). While most S. Indiana isolates (87%, 384/440) were resistant to 13 to 16 of the 16 antibiotics tested, 89% of non-S. Indiana isolates (528/595) were resistant to 0 to 6 antibiotics. Class 1 integrons and IncHI2-type plasmids were detected in all S. Indiana isolates, but only in 39% and 1% of non-S. Indiana isolates. PMID:26824960

  9. Early Onset Neonatal Sepsis Due to Salmonella enterica Serovar 4,5,12:i:-: A Case Report with Literature Review.

    PubMed

    Vongbhavit, Kannikar; Itdhi, Salocha; Panburana, Jantana; Prommalikit, Olarn

    2015-11-01

    The authors report a case of a 36-week male infant born via spontaneous vaginal delivery who developed Salmonella sepsis at HRH Princess Maha Chakri Sirindhorn Medical Center Srinakharinwirot University, Nakhon Nayok, Thailand. He was born to a mother without identifiable risk factors. On day 3, he developed fever tachycardia, lethargy, poor feeding and diarrhea prompting a sepsis evaluation. Blood and stool cultures were positive for S. enterica serovar 4,5,12:i:-. Therefore, Salmonella infection should be considered in the differential diagnosis of early onset neonatal sepsis (EOS) particularly in endemic areas. PMID:27276847

  10. The reaction mechanism for dehydration process catalyzed by type I dehydroquinate dehydratase from Gram-negative Salmonella enterica

    NASA Astrophysics Data System (ADS)

    Yao, Yuan; Li, Ze-Sheng

    2012-01-01

    The fundamental reaction mechanism for the dehydration process catalyzed by type I dehydroquinate dehydratase from Gram-negative Salmonella enterica has been studied by density functional theory calculations. The results indicate that the dehydration process undergoes a two-step cis-elimination mechanism, which is different from the previously proposed one. The catalytic roles of both the highly conserved residue His143 and the Schiff base formed between the substrate and Lys170 have also been elucidated. The structural and mechanistic insight presented here may direct the design of type I dehydroquinate dehydratase enzyme inhibitors as non-toxic antimicrobials, anti-fungals, and herbicides.

  11. Genomic Comparison of Non-Typhoidal Salmonella enterica Serovars Typhimurium, Enteritidis, Heidelberg, Hadar and Kentucky Isolates from Broiler Chickens

    PubMed Central

    Dhanani, Akhilesh S.; Block, Glenn; Dewar, Ken; Forgetta, Vincenzo; Topp, Edward; Beiko, Robert G.; Diarra, Moussa S.

    2015-01-01

    Background Non-typhoidal Salmonella enterica serovars, associated with different foods including poultry products, are important causes of bacterial gastroenteritis worldwide. The colonization of the chicken gut by S. enterica could result in the contamination of the environment and food chain. The aim of this study was to compare the genomes of 25 S. enterica serovars isolated from broiler chicken farms to assess their intra- and inter-genetic variability, with a focus on virulence and antibiotic resistance characteristics. Methodology/Principal Finding The genomes of 25 S. enterica isolates covering five serovars (ten Typhimurium including three monophasic 4,[5],12:i:, four Enteritidis, three Hadar, four Heidelberg and four Kentucky) were sequenced. Most serovars were clustered in strongly supported phylogenetic clades, except for isolates of serovar Enteritidis that were scattered throughout the tree. Plasmids of varying sizes were detected in several isolates independently of serovars. Genes associated with the IncF plasmid and the IncI1 plasmid were identified in twelve and four isolates, respectively, while genes associated with the IncQ plasmid were found in one isolate. The presence of numerous genes associated with Salmonella pathogenicity islands (SPIs) was also confirmed. Components of the type III and IV secretion systems (T3SS and T4SS) varied in different isolates, which could explain in part, differences of their pathogenicity in humans and/or persistence in broilers. Conserved clusters of genes in the T3SS were detected that could be used in designing effective strategies (diagnostic, vaccination or treatments) to combat Salmonella. Antibiotic resistance genes (CMY, aadA, ampC, florR, sul1, sulI, tetAB, and srtA) and class I integrons were detected in resistant isolates while all isolates carried multidrug efflux pump systems regardless of their antibiotic susceptibility profile. Conclusions/Significance This study showed that the predominant

  12. [Agglutination of hen egg-yolk immunoglobulins (IgY) against Salmonella enterica, serovar enteritidis].

    PubMed

    Terzolo, H R; Sandoval, V E; Caffer, M I; Terragno, R; Alcain, A

    1998-01-01

    Two groups of 6 laying hens were used to produce IgY. In the vaccinated group (V), hens were injected by intramuscular route with two doses of a Salmonella enterica serovar Enteritidis bacterin at 20-day interval. In the control group (T) hens remained unvaccinated. Four IgY extractions were performed on the egg production of both groups. The first two extractions were carried out using the yolks obtained from the eggs produced during the 4th and 5th post-vaccination week (extracts 1V and 1T) and the other two using the ones from the 6th, 7th and 8th week (2V and 2T). Starting from the extracts 1V and 1T other products were obtained by freezing-thawing (1V-A and 1T-A) and simple (1V-B and 1T-B) or double (1V-C and 1T-C) flow capillary dialysis concentration. All these products were compared using an ELISA test specific for the detection of chicken antibodies against flagellar antigens of S. Enteritidis. In this test, V extracts were positive whereas T extracts were negative. The extract 1V was more positive than the extract 2V. The extract 1V-C was the most positive and was therefore selected to be used as an antiserum in the agglutination tests. This extract contained 1.9 g/dl of total proteins, 0.028 g/dl of triglycerides and 0.012 g/dl of cholesterol and showed an electrophoretic pattern characteristic of IgY. The 1T-C extract was used as a negative control in the agglutination tests. Slide somatic and tube flagellar agglutination tests were simultaneously carried out using both IgY extracts and a standard rabbit anti-Salmonella (IgG) sera. Overall 367 strains from the Enterobacteriaceae family were tested together with two other strains belonging to the Vibrionaceae family. The 1V-C extract specifically agglutinated S. Enteritidis strains in the same way as the rabbit sera. This extract also agglutinated other Salmonella strains antigenically related to S. Enteritidis. Salmonella which did not share somatic or flagellar antigens with S. Enteritidis, other

  13. Complete genome sequence of Salmonella enterica subspecies arizonae str. RKS2983.

    PubMed

    Wang, Chun-Xiao; Zhu, Song-Ling; Wang, Xiao-Yu; Feng, Ye; Li, Bailiang; Li, Yong-Guo; Johnston, Randal N; Liu, Gui-Rong; Zhou, Jin; Liu, Shu-Lin

    2015-01-01

    Salmonella arizonae (also called Salmonella subgroup IIIa) is a Gram-negative, non-spore-forming, motile, rod-shaped, facultatively anaerobic bacterium. S. arizonae strain RKS2983 was isolated from a human in California, USA. S. arizonae lies somewhere between Salmonella subgroups I (human pathogens) and V (also called S. bongori; usually non-pathogenic to humans) and so is an ideal model organism for studies of bacterial evolution from non-human pathogen to human pathogens. We hence sequenced the genome of RKS2983 for clues of genomic events that might have led to the divergence and speciation of Salmonella into distinct lineages with diverse host ranges and pathogenic features. The 4,574,836 bp complete genome contains 4,203 protein-coding genes, 82 tRNA genes and 7 rRNA operons. This genome contains several characteristics not reported to date in Salmonella subgroup I or V and may provide information about the genetic divergence of Salmonella pathogens. PMID:26203341

  14. Natural surface coating to inactivate Salmonella enterica serovar Typhimurium and maintain quality of cherry tomatoes.

    PubMed

    Yun, Juan; Fan, Xuetong; Li, Xihong; Jin, Tony Z; Jia, Xiaoyu; Mattheis, James P

    2015-01-16

    The objective of the present study was to investigate the effectiveness of zein-based coatings in reducing populations of Salmonella enterica serovar Typhimurium and preserving quality of cherry tomatoes. Tomatoes were inoculated with a cocktail of S. Typhimurium LT2 plus three attenuated strains on the smooth skin surface and stem scar area. The zein-based coatings with and without cinnamon (up to 20%) and mustard essential oil or a commercial wax formulation were applied onto tomatoes and the treated fruits were stored at 10 °C for up to 3 weeks. Populations of S. Typhimurium decreased with increased essential oil concentration and storage duration. S. Typhimurium populations on the smooth skin surface were reduced by 4.6 and 2.8 log colony forming units(CFU)/g by the zein coatings with 20% cinnamon and 20% mustard oil, respectively, 5h after coating. The same coating reduced populations of S. Typhimurium to levels below detection limit (1.0 log CFU/g) on the stem scar area of tomato during 7 days of storage at 10 °C. Salmonella populations were not reduced on fruit coated with the commercial wax. All of the coatings resulted in reduced weight loss compared with uncoated control. Compared with the control, loss of firmness and ascorbic acid during storage was prevented by all of the coatings except the zein coating with 20% mustard oil which enhanced softening. Color was not consistently affected by any of the coating treatments during 21 days of storage at 10°C. The results suggest that the zein-based coating containing cinnamon oil might be used to enhance microbial safety and quality of tomato. PMID:25462924

  15. Eggshell penetration of various types of hens' eggs by Salmonella enterica serovar Enteritidis.

    PubMed

    Messens, Winy; Grijspeerdt, Koen; De Reu, Koen; De Ketelaere, Bart; Mertens, Kristof; Bamelis, Flip; Kemps, Bart; De Baerdemaeker, Josse; Decuypere, Eddy; Herman, Lieve

    2007-03-01

    Egg weight, shell thickness, number of pores, cuticle deposition, eggshell strength (dynamic stiffness and damping ratio), and the ability of Salmonella enterica serovar Enteritidis (SE) to penetrate the eggshell were determined. Penetration was assessed by filling the eggs with a selective medium that allowed viewing of Salmonella growth on the inside of the shell and membrane complex. After inoculation of each shell with on average 2.71 log CFU, the eggs were stored for up to 14 days at 20 degrees C and 60% relative humidity. Commercially available eggs were used. At 14 days of storage, only 6.0% of the eggs from free-range hens and 16.0% of the generic (i.e., eggs from hens in conventional battery cages that were given standard feed) white eggs were penetrated. The generic brown, organic, and omega-3-enriched eggs were penetrated at a frequency of 30 to 34%. In a second experiment it was shown that the layer strains of the hen (ISA-Brown Warren versus Bovans Goldline), which were kept in furnished cages, did not affect eggshell penetration by SE. For Bovans Goldline hens, the housing system (furnished cage versus aviary) did not affect penetration, while a trend was visible toward a higher fraction of penetrated eggshells when hens were fed corncob mix rather than standard feed. Eggshell penetration was observed more frequently in the absence of cuticle spots and for eggs having lower dynamic stiffness values. Shell contamination at the end of storage was highly correlated with SE penetration. PMID:17388050

  16. Characterization of antimicrobial resistance in Salmonella enterica strains isolated from Brazilian poultry production.

    PubMed

    Mattiello, Samara P; Drescher, Guilherme; Barth, Valdir C; Ferreira, Carlos A S; Oliveira, Sílvia D

    2015-11-01

    Antimicrobial resistance profiles and presence of resistance determinants and integrons were evaluated in Salmonella enterica strains from Brazilian poultry. The analysis of 203 isolates showed that those from the poultry environment (88 isolates) were significantly more resistant to antimicrobials than isolates from other sources, particularly those isolated from poultry by-product meal (106 isolates). Thirty-seven isolates were resistant to at least three antimicrobial classes. Class 1 integrons were detected in 26 isolates, and the analysis of the variable region between the 5' conserved segment (CS) and 3' CS of each class 1 integron-positive isolate showed that 13 contained a typical 3' CS and 14 contained an atypical 3' CS. One Salmonella Senftenberg isolate harbored two class 1 integrons, showing both typical and atypical 3' CSs. The highest percentage of resistance was found to sulfonamides, and sul genes were detected in the majority of the resistant isolates. Aminoglycoside resistance was detected in 50 isolates, and aadA and aadB were present in 28 and 32 isolates, respectively. In addition, strA and strB were detected in 78.1 and 65.6% isolates resistant to streptomycin, respectively. Twenty-one isolates presented reduced susceptibility to β-lactams and harbored bla(TEM), bla(CMY), and/or bla(CTX-M). Forty isolates showed reduced susceptibility to tetracycline, and most presented tet genes. These results highlight the importance of the environment as a reservoir of resistant Salmonella, which may enable the persistence of resistance determinants in the poultry production chain, contributing, therefore, to the debate regarding the impacts that antimicrobial use in animal production may exert in human health. PMID:26337044

  17. Evolution of Salmonella enterica Virulence via Point Mutations in the Fimbrial Adhesin

    PubMed Central

    Kisiela, Dagmara I.; Chattopadhyay, Sujay; Libby, Stephen J.; Karlinsey, Joyce E.; Fang, Ferric C.; Tchesnokova, Veronika; Kramer, Jeremy J.; Beskhlebnaya, Viktoriya; Samadpour, Mansour; Grzymajlo, Krzysztof; Ugorski, Maciej; Lankau, Emily W.; Mackie, Roderick I.; Clegg, Steven; Sokurenko, Evgeni V.

    2012-01-01

    Whereas the majority of pathogenic Salmonella serovars are capable of infecting many different animal species, typically producing a self-limited gastroenteritis, serovars with narrow host-specificity exhibit increased virulence and their infections frequently result in fatal systemic diseases. In our study, a genetic and functional analysis of the mannose-specific type 1 fimbrial adhesin FimH from a variety of serovars of Salmonella enterica revealed that specific mutant variants of FimH are common in host-adapted (systemically invasive) serovars. We have found that while the low-binding shear-dependent phenotype of the adhesin is preserved in broad host-range (usually systemically non-invasive) Salmonella, the majority of host-adapted serovars express FimH variants with one of two alternative phenotypes: a significantly increased binding to mannose (as in S. Typhi, S. Paratyphi C, S. Dublin and some isolates of S. Choleraesuis), or complete loss of the mannose-binding activity (as in S. Paratyphi B, S. Choleraesuis and S. Gallinarum). The functional diversification of FimH in host-adapted Salmonella results from recently acquired structural mutations. Many of the mutations are of a convergent nature indicative of strong positive selection. The high-binding phenotype of FimH that leads to increased bacterial adhesiveness to and invasiveness of epithelial cells and macrophages usually precedes acquisition of the non-binding phenotype. Collectively these observations suggest that activation or inactivation of mannose-specific adhesive properties in different systemically invasive serovars of Salmonella reflects their dynamic trajectories of adaptation to a life style in specific hosts. In conclusion, our study demonstrates that point mutations are the target of positive selection and, in addition to horizontal gene transfer and genome degradation events, can contribute to the differential pathoadaptive evolution of Salmonella. PMID:22685400

  18. The genome sequence of Salmonella enterica serovar Choleraesuis, a highly invasive and resistant zoonotic pathogen

    PubMed Central

    Chiu, Cheng-Hsun; Tang, Petrus; Chu, Chishih; Hu, Songnian; Bao, Qiyu; Yu, Jun; Chou, Yun-Ying; Wang, Hsin-Shih; Lee, Ying-Shiung

    2005-01-01

    Salmonella enterica serovar Choleraesuis (S.Choleraesuis), a highly invasive serovar among non-typhoidal Salmonella, usually causes sepsis or extra-intestinal focal infections in humans. S.Choleraesuis infections have now become particularly difficult to treat because of the emergence of resistance to multiple antimicrobial agents. The 4.7 Mb genome sequence of a multidrug-resistant S.Choleraesuis strain SC-B67 was determined. Genome wide comparison of three sequenced Salmonella genomes revealed that more deletion events occurred in S.Choleraesuis SC-B67 and S.Typhi CT18 relative to S.Typhimurium LT2. S.Choleraesuis has 151 pseudogenes, which, among the three Salmonella genomes, include the highest percentage of pseudogenes arising from the genes involved in bacterial chemotaxis signal-transduction pathways. Mutations in these genes may increase smooth swimming of the bacteria, potentially allowing more effective interactions with and invasion of host cells to occur. A key regulatory gene of TetR/AcrR family, acrR, was inactivated through the introduction of an internal stop codon resulting in overexpression of AcrAB that appears to be associated with ciprofloxacin resistance. While lateral gene transfer providing basic functions to allow niche expansion in the host and environment is maintained during the evolution of different serovars of Salmonella, genes providing little overall selective benefit may be lost rapidly. Our findings suggest that the formation of pseudogenes may provide a simple evolutionary pathway that complements gene acquisition to enhance virulence and antimicrobial resistance in S.Choleraesuis. PMID:15781495

  19. Review of induced molting by feed removal and contamination of eggs with Salmonella enterica serovar Enteritidis.

    PubMed

    Golden, Neal J; Marks, Harry H; Coleman, Margaret E; Schroeder, Carl M; Bauer, Nathan E; Schlosser, Wayne D

    2008-10-15

    As laying hens age, egg production and quality decreases. Egg producers can impose an induced molt on older hens that results in increased egg productivity and decreased hen mortality compared with non-molted hens of the same age. This review discusses the effect of induced molting by feed removal on immune parameters, Salmonella enterica serovar Enteritidis (SE) invasion and subsequent production of SE-contaminated eggs. Experimental oral infections with SE show molted hens are more susceptible to SE infection and produce more SE-contaminated eggs in the first few weeks post-molt compared with pre-molt egg production. In addition, it appears that molted hens are more likely to disseminate SE into their environment. Molted hens are more susceptible to SE infection by contact exposure to experimentally infected hens; thus, transmission of SE among molted hens could be more rapid than non-molted birds. Histological examination of the gastrointestinal tracts of molted SE-infected hens revealed more frequent and severe intestinal mucosal lesions compared with non-molted SE-infected hens. These data suggest that induced molting by feed deprivation alters the normal asymptomatic host-pathogen relationship. Published data suggest the highest proportion of SE-positive eggs is produced within 1-5 weeks post-molt and decreases sharply by 6-10 weeks and dissipates to the background level for non-molted hens by 11-20 weeks. Appropriate treatment measures of eggs produced in the fist 5 weeks post-molting may decrease the risk of foodborne infections to humans. PMID:18479846

  20. Survival and fate of Salmonella enterica serovar Montevideo in adult horn flies (Diptera: Muscidae).

    PubMed

    Olafson, Pia Untalan; Lohmeyer, Kimberly H; Edrington, Thomas S; Loneragan, Guy H

    2014-09-01

    Contamination of cattle peripheral lymph nodes with Salmonella enterica is proposed to occur via a transdermal route of entry. If so, bacteria may be introduced to cattle by biting arthropods. Biting flies, such as horn flies (Haematobia irritans irritans (L.)) (Diptera: Muscidae), are intriguing candidates for transmitting Salmonella to cattle because they provide a route of entry when they breach the skin barrier during blood feeding. Using a green fluorescent protein-expressing strain of Salmonella Montevideo (S. Montevideo-GFP), the current study demonstrated that horn fly grooming subsequent to tactile exposure to the bacteria resulted in acquisition of the bacteria on mouthparts as well as microbial ingestion. Consumption of a bloodmeal containing approximately 10(2), approximately 10(4), or 10(6) S. Montevideo-GFP resulted in horn fly colonization for up to 72 h postingestion (PI). Epifluorescent microscopy indicated that the bacteria were not localized to the crop but were observed within the endoperitrophic space, suggesting that regurgitation is not a primary route of transmission. S. Montevideo-GFP were cultured from excreta of 100% of flies beginning 6-7 h PI of a medium or high dose meal and > 12 h PI in excreta from 60% of flies fed the low-dose meal. Animal hides and manure pats are sources for horn flies to acquire the Salmonella and mechanically transmit them to an animal while feeding. Mean quantities of 5.65-67.5 x 10(2) CFU per fly were cultured from fly excreta passed within 1 d after feeding, suggesting the excreta can provide an additional microbial source on the animal's hide. PMID:25276929