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Molecular characterization of antibiotic resistant Salmonella Typhimurium and Salmonella Kentucky isolated from pre- and post-chill whole broilers carcasses. Food Microbiol 2013; 38:6-15. [PMID: 24290620 DOI: 10.1016/j.fm.2013.08.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 08/02/2013] [Accepted: 08/10/2013] [Indexed: 11/23/2022]
Abstract
There is conflicting data regarding whether commercial chilling has any effect on persistence of Salmonella serovars, including antibiotic resistant variants, on chicken carcasses. A total of 309 Salmonella Typhimurium and Salmonella Kentucky isolates recovered from pre- and post-chill whole broiler carcasses were characterized for genetic relatedness using Pulsed Field Gel Electrophoresis (PFGE) and for the presence of virulence factors (invA, pagC, spvC) by PCR and for aerobactin and colicin production by bioassays. A subset of these isolates (n = 218) displaying resistance to either sulfisoxazole and/or ceftiofur [S. Typhimurium (n = 66) and S. Kentucky (n = 152)] were further tested for the presence of associated antibiotic resistance elements (class-I integrons and blaCMY genes) by PCR. All 145 ceftiofur resistant S. Kentucky and S. Typhimurium isolates possessed blaCMY genes. Class-I integrons were only detected in 6.1% (n = 4/66) of sulfisoxazole resistant S. Typhimurium isolates. The PFGE analysis revealed the presence of genetically diverse populations within the recovered isolates but clusters were generally concordant with serotypes and antimicrobial resistance profiles. At a 100% pattern similarity index, thirty-six percent of the undistinguishable S. Typhimurium and 22% of the undistinguishable S. Kentucky isolates were recovered from the same chilling step. All isolates possessed the invA and pagC genes, but only 1.4%possessed spvC. Irrespective of the chilling step, there was a significant difference (P < 0.05) in the production of aerobactin and colicin between S. Typhimurium and S. Kentucky isolates. Taken together, these results indicate that chilling impacted the recovery of particular Salmonella clonal groups but had no effect on the presence of class-I integrons, blaCMY genes, and tested virulence factors.
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52
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Pathoadaptive mutations in Salmonella enterica isolated after serial passage in mice. PLoS One 2013; 8:e70147. [PMID: 23936152 PMCID: PMC3723669 DOI: 10.1371/journal.pone.0070147] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 06/20/2013] [Indexed: 12/18/2022] Open
Abstract
How pathogenic bacteria adapt and evolve in the complex and variable environment of the host remains a largely unresolved question. Here we have used whole genome sequencing of Salmonella enterica serovar Typhimurium LT2 populations serially passaged in mice to identify mutations that adapt bacteria to systemic growth in mice. We found unique pathoadaptive mutations in two global regulators, phoQ and stpA, which increase the competitive indexes of the bacteria 3- to 5-fold. Also, all mouse-adapted lineages had changed the orientation of the hin invertable element, resulting in production of a FliC type of flagellum. Competition experiments in mice with locked flagellum mutants showed that strains expressing the FliC type of flagellum had a 5-fold increase in competitive index as compared to those expressing FljB type flagellum. Combination of the flagellum cassette inversion with the stpA mutation increased competitive indexes up to 20-fold. These experiments show that Salmonella can rapidly adapt to a mouse environment by acquiring a few mutations of moderate individual effect that when combined confer substantial increases in growth.
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53
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Kim YM, Schmidt BJ, Kidwai AS, Jones MB, Deatherage Kaiser BL, Brewer HM, Mitchell HD, Palsson BO, McDermott JE, Heffron F, Smith RD, Peterson SN, Ansong C, Hyduke DR, Metz TO, Adkins JN. Salmonella modulates metabolism during growth under conditions that induce expression of virulence genes. MOLECULAR BIOSYSTEMS 2013; 9:1522-34. [PMID: 23559334 PMCID: PMC3665296 DOI: 10.1039/c3mb25598k] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium) is a facultative pathogen that uses complex mechanisms to invade and proliferate within mammalian host cells. To investigate possible contributions of metabolic processes to virulence in S. Typhimurium grown under conditions known to induce expression of virulence genes, we used a metabolomics-driven systems biology approach coupled with genome-scale modeling. First, we identified distinct metabolite profiles associated with bacteria grown in either rich or virulence-inducing media and report the most comprehensive coverage of the S. Typhimurium metabolome to date. Second, we applied an omics-informed genome-scale modeling analysis of the functional consequences of adaptive alterations in S. Typhimurium metabolism during growth under our conditions. Modeling efforts highlighted a decreased cellular capability to both produce and utilize intracellular amino acids during stationary phase culture in virulence conditions, despite significant abundance increases for these molecules as observed by our metabolomics measurements. Furthermore, analyses of omics data in the context of the metabolic model indicated rewiring of the metabolic network to support pathways associated with virulence. For example, cellular concentrations of polyamines were perturbed, as well as the predicted capacity for secretion and uptake.
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Affiliation(s)
- Young-Mo Kim
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Brian J. Schmidt
- Department of Bioengineering, University of California at San Diego, San Diego, CA 92093
| | - Afshan S. Kidwai
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97239
| | | | - Brooke L. Deatherage Kaiser
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Heather M. Brewer
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Hugh D. Mitchell
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Bernhard O. Palsson
- Department of Bioengineering, University of California at San Diego, San Diego, CA 92093
| | - Jason E. McDermott
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Fred Heffron
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97239
| | - Richard D. Smith
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352
| | | | - Charles Ansong
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Daniel R. Hyduke
- Department of Bioengineering, University of California at San Diego, San Diego, CA 92093
| | - Thomas O. Metz
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Joshua N. Adkins
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352
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54
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Suez J, Porwollik S, Dagan A, Marzel A, Schorr YI, Desai PT, Agmon V, McClelland M, Rahav G, Gal-Mor O. Virulence gene profiling and pathogenicity characterization of non-typhoidal Salmonella accounted for invasive disease in humans. PLoS One 2013; 8:e58449. [PMID: 23505508 PMCID: PMC3591323 DOI: 10.1371/journal.pone.0058449] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 02/05/2013] [Indexed: 12/27/2022] Open
Abstract
Human infection with non-typhoidal Salmonella serovars (NTS) infrequently causes invasive systemic disease and bacteremia. To understand better the nature of invasive NTS (iNTS), we studied the gene content and the pathogenicity of bacteremic strains from twelve serovars (Typhimurium, Enteritidis, Choleraesuis, Dublin, Virchow, Newport, Bredeney, Heidelberg, Montevideo, Schwarzengrund, 9,12:l,v:- and Hadar). Comparative genomic hybridization using a Salmonella enterica microarray revealed a core of 3233 genes present in all of the iNTS strains, which include the Salmonella pathogenicity islands 1-5, 9, 13, 14; five fimbrial operons (bcf, csg, stb, sth, sti); three colonization factors (misL, bapA, sinH); and the invasion gene, pagN. In the iNTS variable genome, we identified 16 novel genomic islets; various NTS virulence factors; and six typhoid-associated virulence genes (tcfA, cdtB, hlyE, taiA, STY1413, STY1360), displaying a wider distribution among NTS than was previously known. Characterization of the bacteremic strains in C3H/HeN mice showed clear differences in disease manifestation. Previously unreported characterization of serovars Schwarzengrund, 9,12:l,v:-, Bredeney and Virchow in the mouse model showed low ability to elicit systemic disease, but a profound and elongated shedding of serovars Schwarzengrund and 9,12:l,v:- (as well as Enteritidis and Heidelberg) due to chronic infection of the mouse. Phenotypic comparison in macrophages and epithelial cell lines demonstrated a remarkable intra-serovar variation, but also showed that S. Typhimurium bacteremic strains tend to present lower intracellular growth than gastroenteritis isolates. Collectively, our data demonstrated a common core of virulence genes, which might be required for invasive salmonellosis, but also an impressive degree of genetic and phenotypic heterogeneity, highlighting that bacteremia is a complex phenotype, which cannot be attributed merely to an enhanced invasion or intracellular growth of a particular strain.
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Affiliation(s)
- Jotham Suez
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Steffen Porwollik
- The Vaccine Research Institute of San Diego, San Diego, California, United States of America
| | - Amir Dagan
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel
| | - Alex Marzel
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yosef Ilan Schorr
- Government Central Laboratories, Ministry of Health, Jerusalem, Israel
| | - Prerak T. Desai
- The Vaccine Research Institute of San Diego, San Diego, California, United States of America
| | - Vered Agmon
- Government Central Laboratories, Ministry of Health, Jerusalem, Israel
| | - Michael McClelland
- The Vaccine Research Institute of San Diego, San Diego, California, United States of America
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, California, United States of America
| | - Galia Rahav
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ohad Gal-Mor
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel
- * E-mail:
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Kong W, Brovold M, Koeneman BA, Clark-Curtiss J, Curtiss R. Turning self-destructing Salmonella into a universal DNA vaccine delivery platform. Proc Natl Acad Sci U S A 2012; 109:19414-9. [PMID: 23129620 PMCID: PMC3511069 DOI: 10.1073/pnas.1217554109] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We previously developed a biological containment system using recombinant Salmonella Typhimurium strains that are attenuated yet capable of synthesizing protective antigens. The regulated delayed attenuation and programmed self-destructing features designed into these S. Typhimurium strains enable them to efficiently colonize host tissues and allow release of the bacterial cell contents after lysis. To turn such a recombinant attenuated Salmonella vaccine (RASV) strain into a universal DNA vaccine-delivery vehicle, our approach was to genetically modify RASV strains to display a hyperinvasive phenotype to maximize Salmonella host entry and host cell internalization, to enable Salmonella endosomal escape to release a DNA vaccine into the cytosol, and to decrease Salmonella-induced pyroptosis/apoptosis that allows the DNA vaccine time to traffic to the nucleus for efficient synthesis of encoded protective antigens. A DNA vaccine vector that encodes a domain that contributes to the arabinose-regulated lysis phenotype but has a eukaryotic promoter was constructed. The vector was then improved by insertion of multiple DNA nuclear-targeting sequences for efficient nuclear trafficking and gene expression, and by increasing nuclease resistance to protect the plasmid from host degradation. A DNA vaccine encoding influenza WSN virus HA antigen delivered by the RASV strain with the best genetic attributes induced complete protection to mice against a lethal influenza virus challenge. Adoption of these technological improvements will revolutionize means for effective delivery of DNA vaccines to stimulate mucosal, systemic, and cellular protective immunities, and lead to a paradigm shift in cost-effective control and prevention of a diversity of diseases.
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MESH Headings
- Active Transport, Cell Nucleus
- Animals
- Antibodies, Bacterial/immunology
- Antibody Formation/immunology
- Apoptosis
- Base Sequence
- Deoxyribonucleases/metabolism
- Gene Transfer Techniques
- Genes, Bacterial/genetics
- Genetic Engineering
- Genetic Vectors/genetics
- Hemagglutinin Glycoproteins, Influenza Virus/immunology
- Immunization
- Mice
- Molecular Sequence Data
- Plasmids/genetics
- Salmonella/genetics
- Salmonella/immunology
- Salmonella Infections, Animal/immunology
- Salmonella Infections, Animal/microbiology
- Salmonella Infections, Animal/prevention & control
- Salmonella Vaccines/immunology
- Vaccines, Attenuated/immunology
- Vaccines, DNA/immunology
- Vaccines, Synthetic/immunology
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Affiliation(s)
- Wei Kong
- Center for Infectious Diseases and Vaccinology at the Biodesign Institute, and
| | - Matthew Brovold
- Center for Infectious Diseases and Vaccinology at the Biodesign Institute, and
| | | | - Josephine Clark-Curtiss
- Center for Infectious Diseases and Vaccinology at the Biodesign Institute, and
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-5401; and
| | - Roy Curtiss
- Center for Infectious Diseases and Vaccinology at the Biodesign Institute, and
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-5401; and
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56
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Microbiological analysis of nontyphoidal Salmonella strains causing distinct syndromes of bacteremia or enteritis in HIV/AIDS patients in San Diego, California. J Clin Microbiol 2012; 50:3598-603. [PMID: 22933605 DOI: 10.1128/jcm.00795-12] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recurrent invasive nontyphoidal Salmonella (NTS) infection is an AIDS-defining illness that has become less common in the developed world in the era of highly active antiretroviral therapy (HAART), while it has emerged as a major public health problem in developing countries, particularly sub-Saharan Africa. We retrospectively analyzed Salmonella (NTS) infection in HIV/AIDS patients from June 2003 until December 2009 at the University of California, San Diego (UCSD), Medical Center. Bacterial isolates from all patients were tested for selected microbiological properties, including major Salmonella (NTS) virulence loci rpoS, sodCI, spvB, and sseI. Fourteen percent of all Salmonella (NTS) cases recorded at the UCSD Medical Center during this period occurred in known HIV/AIDS patients. The clinical presentations in HIV patients fell into two distinct groups, bacteremia and enteritis. There was little clinical overlap between these two syndromes. All strains were positive for the presence of the rpoS and sodCI virulence loci, and 75% of strains were positive for the presence of the spvB and sseI loci. Antibiotic susceptibility assay showed that all strains were susceptible to trimethoprim-sulfamethoxazole and ciprofloxacin. The clinical presentation did not have a clear relationship to the CD4(+) cell count. Of the bacteremic isolates, all but one isolate, drawn from a patient with substantial enteric comorbidities, had all of the virulence genes tested, but 66% of nonbacteremic, enteritis strains also contained all the tested virulence loci. In conclusion, neither patients' CD4(+) cell count nor bacterial strain properties necessarily predicted the clinical presentation of HIV/AIDS patients with Salmonella (NTS) infection, and AIDS patients can have episodes of Salmonella enteritis without dissemination.
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57
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Williams LE, Wireman J, Hilliard VC, Summers AO. Large plasmids of Escherichia coli and Salmonella encode highly diverse arrays of accessory genes on common replicon families. Plasmid 2012; 69:36-48. [PMID: 22939841 DOI: 10.1016/j.plasmid.2012.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 08/09/2012] [Accepted: 08/13/2012] [Indexed: 11/17/2022]
Abstract
Plasmids are important in evolution and adaptation of host bacteria, yet we lack a comprehensive picture of their own natural variation. We used replicon typing and RFLP analysis to assess diversity and distribution of plasmids in the ECOR, SARA, SARB and SARC reference collections of Escherichia coli and Salmonella. Plasmids, especially large (≥30 kb) plasmids, are abundant in these collections. Host species and genotype clearly impact plasmid prevalence; plasmids are more abundant in ECOR than SAR, but, within ECOR, subgroup B2 strains have the fewest large plasmids. The majority of large plasmids have unique RFLP patterns, suggesting high variation, even within dominant replicon families IncF and IncI1. We found only four conserved plasmid types within ECOR, none of which are widely distributed. Within SAR, conserved plasmid types are primarily serovar-specific, including a pSLT-like plasmid in 13 Typhimurium strains. Conservation of pSLT contrasts with variability of other plasmids, suggesting evolution of serovar-specific virulence plasmids is distinct from that of most enterobacterial plasmids. We sequenced a conserved serovar Heidelberg plasmid but did not detect virulence or antibiotic resistance genes. Our data illustrate the high degree of natural variation in large plasmids of E. coli and Salmonella, even among plasmids sharing backbone genes.
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Affiliation(s)
- Laura E Williams
- Department of Microbiology, University of Georgia, Athens, GA 30602-2605, USA.
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58
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Dunkley KD, Callaway TR, O'Bryan CA, Kundinger MM, Dunkley CS, Anderson RC, Nisbet DJ, Crandall PG, Ricke SC. Comparison of Real Time Polymerase Chain Reaction Quantification of Changes inhilAandrpoSGene Expression of aSalmonellaTyphimurium Poultry Isolate Grown at Fast Versus Slow Dilution Rates in an Anaerobic Continuous Culture System. FOOD BIOTECHNOL 2012. [DOI: 10.1080/08905436.2012.698770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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59
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Feng Y, Liu J, Li YG, Cao FL, Johnston RN, Zhou J, Liu GR, Liu SL. Inheritance of the Salmonella virulence plasmids: Mostly vertical and rarely horizontal. INFECTION GENETICS AND EVOLUTION 2012; 12:1058-63. [DOI: 10.1016/j.meegid.2012.03.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 03/03/2012] [Accepted: 03/06/2012] [Indexed: 11/26/2022]
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60
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Figueira R, Holden DW. Functions of the Salmonella pathogenicity island 2 (SPI-2) type III secretion system effectors. Microbiology (Reading) 2012; 158:1147-1161. [DOI: 10.1099/mic.0.058115-0] [Citation(s) in RCA: 253] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- Rita Figueira
- Section of Microbiology, Centre for Molecular Microbiology and Infection, Imperial College London, Armstrong Road, London SW7 2AZ, UK
| | - David W. Holden
- Section of Microbiology, Centre for Molecular Microbiology and Infection, Imperial College London, Armstrong Road, London SW7 2AZ, UK
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61
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Brooks JT, Matyas BT, Fontana J, DeGroot MA, Beuchat LR, Hoekstra M, Friedman CR. An outbreak of Salmonella serotype Typhimurium infections with an unusually long incubation period. Foodborne Pathog Dis 2012; 9:245-8. [PMID: 22283668 DOI: 10.1089/fpd.2011.0992] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A 1998 investigation of an outbreak of Salmonella serotype Typhimurium infections among children tasting unpasteurized milk during tours of a dairy farm demonstrated a distribution of unusually long incubation periods (median, 8 days; interquartile range [IQR], 6-14 days). Bacterial isolates were highly acid tolerant and contained genes associated with protection against destructive phagocytic reactive oxygen intermediates. We hypothesize that exposure to low-dose oral inoculum of a pathogen with these properties could have contributed to cases of non-typhoidal salmonellosis with the longest incubation period reported to the Centers for Disease Control and Prevention (CDC).
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Affiliation(s)
- John T Brooks
- Foodborne and Diarrheal Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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Ogilvie LA, Firouzmand S, Jones BV. Evolutionary, ecological and biotechnological perspectives on plasmids resident in the human gut mobile metagenome. Bioeng Bugs 2012; 3:13-31. [PMID: 22126801 PMCID: PMC3329251 DOI: 10.4161/bbug.3.1.17883] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Numerous mobile genetic elements (MGE) are associated with the human gut microbiota and collectively referred to as the gut mobile metagenome. The role of this flexible gene pool in development and functioning of the gut microbial community remains largely unexplored, yet recent evidence suggests that at least some MGE comprising this fraction of the gut microbiome reflect the co-evolution of host and microbe in the gastro-intestinal tract. In conjunction, the high level of novel gene content typical of MGE coupled with their predicted high diversity, suggests that the mobile metagenome constitutes an immense and largely unexplored gene-space likely to encode many novel activities with potential biotechnological or pharmaceutical value, as well as being important to the development and functioning of the gut microbiota. Of the various types of MGE that comprise the gut mobile metagenome, plasmids are of particular importance since these elements are often capable of autonomous transfer between disparate bacterial species, and are known to encode accessory functions that increase bacterial fitness in a given environment facilitating bacterial adaptation. In this article current knowledge regarding plasmids resident in the human gut mobile metagenome is reviewed, and available strategies to access and characterize this portion of the gut microbiome are described. The relative merits of these methods and their present as well as prospective impact on our understanding of the human gut microbiota is discussed.
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Affiliation(s)
- Lesley A Ogilvie
- Centre for Biomedical and Health Science Research, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK
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63
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Tzeng JI, Chu CH, Chen SW, Yeh CM, Chiu CH, Chiou CS, Lin JH, Chu C. Reduction of Salmonella enterica serovar Choleraesuis carrying large virulence plasmids after the foot and mouth disease outbreak in swine in southern Taiwan, and their independent evolution in human and pig. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2011; 45:418-25. [PMID: 22209685 DOI: 10.1016/j.jmii.2011.12.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 06/20/2011] [Accepted: 12/08/2011] [Indexed: 10/14/2022]
Abstract
BACKGROUND/PURPOSE Salmonella enterica serovar Choleraesuis (S. Choleraesuis) is a highly invasive zoonotic pathogen that causes bacteremia in humans and pigs. The prevalence of S. Choleraesuis in man has gradually decreased since the outbreak of foot and mouth disease in pigs in 1997 in southern Taiwan. The goal of this study was to investigate the change in prevalence of S. Choleraesuis carrying the virulence plasmid (pSCV) in human and swine isolates collected in 1995-2005 and characterize these. METHODS 380 isolates were collected from human and swine blood samples. Large pSCVs were determined by PCR and Southern blot analysis. Antimicrobial susceptibility and resistance genes, and the phylogenetic association of these large pSCV were analyzed. RESULTS The number of isolates harboring the large pSCV was significantly reduced, and their prevalence differed between human and swine isolates. These large pSCVs were a recombinant of original 50-kb pSCV and R plasmid. In addition, some large pSCVs lacked two pSCV-specific deletion regions from pef to repC and from traT to samA. These large pSCVs carried the resistance genes bla(TEM,)aadA2, and sulI, as well as class I integrons of 0.65 and/or 1.9 kb in size, but were inconjugatible. Phylogenetic analysis demonstrated that the large pSCV evolves independently in human and swine isolates. CONCLUSION S. Choleraesuis with large pSCV was significantly reduced after the foot and mouth disease outbreak and may evolve in human and swine specific isolates.
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Affiliation(s)
- Jann-Inn Tzeng
- Department of Anesthesiology, Chi Mei Medical Center, Yong Kang City, Tainan, Taiwan, ROC
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64
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Abstract
In their stressful natural environments, bacteria often are in stationary phase and use their limited resources for maintenance and stress survival. Underlying this activity is the general stress response, which in Escherichia coli depends on the σS (RpoS) subunit of RNA polymerase. σS is closely related to the vegetative sigma factor σ70 (RpoD), and these two sigmas recognize similar but not identical promoter sequences. During the postexponential phase and entry into stationary phase, σS is induced by a fine-tuned combination of transcriptional, translational, and proteolytic control. In addition, regulatory "short-cuts" to high cellular σS levels, which mainly rely on the rapid inhibition of σS proteolysis, are triggered by sudden starvation for various nutrients and other stressful shift conditons. σS directly or indirectly activates more than 500 genes. Additional signal input is integrated by σS cooperating with various transcription factors in complex cascades and feedforward loops. Target gene products have stress-protective functions, redirect metabolism, affect cell envelope and cell shape, are involved in biofilm formation or pathogenesis, or can increased stationary phase and stress-induced mutagenesis. This review summarizes these diverse functions and the amazingly complex regulation of σS. At the molecular level, these processes are integrated with the partitioning of global transcription space by sigma factor competition for RNA polymerase core enzyme and signaling by nucleotide second messengers that include cAMP, (p)ppGpp, and c-di-GMP. Physiologically, σS is the key player in choosing between a lifestyle associated with postexponential growth based on nutrient scavenging and motility and a lifestyle focused on maintenance, strong stress resistance, and increased adhesiveness. Finally, research with other proteobacteria is beginning to reveal how evolution has further adapted function and regulation of σS to specific environmental niches.
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65
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Molecular epidemiology of Salmonella enterica serovar typhimurium isolates from cattle in hokkaido, Japan: evidence of clonal replacement and characterization of the disseminated clone. Appl Environ Microbiol 2011; 77:1739-50. [PMID: 21239560 DOI: 10.1128/aem.01910-10] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The molecular epidemiology of 545 Salmonella enterica serovar Typhimurium isolates collected between 1977 and 2009 from cattle in Hokkaido, Japan, was investigated using pulsed-field gel electrophoresis (PFGE). Nine main clusters were identified from 116 PFGE patterns. Cluster I comprised 248 isolates, 243 of which possessed a sequence specific to definitive phage type 104 (DT104) or U302. The cluster I isolates were dominant in 1993 to 2003, but their numbers declined beginning in 2004. Beginning in 2002, an increase was observed in the number of cluster VII isolates, consisting of 21 PFGE patterns comprising 165 isolates. A total of 116 isolates representative of the 116 PFGE profiles were analyzed by multilocus variable-number tandem-repeat analysis (MLVA). Other than two drug-sensitive isolates, 19 isolates within cluster VII were classified in the same cluster by MLVA. Among the cluster VII isolates, an antibiotic resistance type showing resistance to ampicillin, chloramphenicol, streptomycin, sulfonamides, tetracycline, kanamycin, cefazolin, and sulfamethoxazole-trimethoprim and a resistance type showing resistance to ampicillin, streptomycin, sulfonamides, tetracycline, and kanamycin were found in 23 and 125 isolates, respectively. In the 19 isolates representative of cluster VII, the bla(TEM-1) gene was found on a Salmonella serotype Typhimurium virulence plasmid, which was transferred to Escherichia coli by electroporation along with resistance to two to four other antimicrobials. Genomic analysis by subtractive hybridization and plasmid analysis suggested that the bla(TEM-1)-carrying virulence plasmid has a mosaic structure composed of elements of different origin. These results indicate an emerging multidrug-resistant S. Typhimurium clone carrying a virulence-resistance plasmid among cattle in Hokkaido, Japan.
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Amano F. SEp22, Salmonella Dps, a Key Molecule Bearing Both Pathogenicity and Resistance to Environmental Stresses in Salmonella. ACTA ACUST UNITED AC 2011. [DOI: 10.1248/jhs.57.458] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Fumio Amano
- Laboratory of Biodefense & Regulation, Osaka University of Pharmaceutical Sciences
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García-Quintanilla M, Casadesús J. Virulence plasmid interchange between strains ATCC 14028, LT2, and SL1344 of Salmonella enterica serovar Typhimurium. Plasmid 2010; 65:169-75. [PMID: 21145349 DOI: 10.1016/j.plasmid.2010.12.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 11/22/2010] [Accepted: 12/03/2010] [Indexed: 11/25/2022]
Abstract
Strains ATCC 14028 and SL1344 of Salmonella enterica serovar Typhimurium are more virulent than LT2 in the BALB/c mouse model. Virulence plasmid swapping between strains ATCC 14208, LT2, and SL1344 does not alter their competitive indexes during mouse infection, indicating that the three plasmids are functionally equivalent, and that their contribution to virulence is independent from the host background. Strains ATCC 14028 and LT2 are more efficient than SL1344 as conjugal donors of the virulence plasmid. Virulence plasmid swapping indicates that reduced ability of conjugal transfer is a property of the SL1344 plasmid, not of the host strain. An A→V amino acid substitution in the TraG protein appears to be the major cause that reduces conjugal transfer in the virulence plasmid of SL1344. Additional sequence differences in the tra operon are found between the SL1344 plasmid and the ATCC 14028 and LT2 plasmids. Divergence in the tra operon may reflect the occurrence of genetic drift either after laboratory domestication or in the environment. The latter might provide evidence that possession of conjugal transfer functions is a neutral trait in Salmonella populations, a view consistent with the abundance of Salmonella isolates whose virulence plasmids are non-conjugative.
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68
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Kwon HJ, Cho SH. Pathogenicity of SG 9R, a rough vaccine strain against fowl typhoid. Vaccine 2010; 29:1311-8. [PMID: 21134445 DOI: 10.1016/j.vaccine.2010.11.067] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 11/16/2010] [Accepted: 11/22/2010] [Indexed: 10/18/2022]
Abstract
SG 9R, a rough vaccine strain of Salmonella gallinarum, has been used for the prevention of fowl typhoid and paratyphoid in the world despite the presence of residual virulence. SG 9R-like rough strains have been recently isolated from fowl typhoid cases; however, molecular markers to differentiate SG 9R from field strains are not well-characterized and the molecular mechanisms of SG 9R residual virulence are unclear. Therefore, we analyzed LPS biosynthesis (rfa gene cluster) and virulence genes (spv, SPI-2) of both SG 9R and S. gallinarum rough field strains. SG 9R carried a unique nonsense mutation in rfaJ (TCA to TAA) and a shared rfaZ mutation (G-deletion) by rough and smooth S. gallinarum strains. SG 9R also carried intact SPI-2 and spvC, B, A, and R (except deleted spvD). SG 9R-like rough strains (n=10) carried identical mutations in virulence-related genes to SG 9R. SG 9R and SG 9R-like rough strains did not demonstrate significant mortality or liver lesions under normal conditions. However, fowl typhoid was successfully reproduced in the present study by SG 9R inoculation to 1-day-old male brown layer chicks per os following starvation. Therefore, the LPS defect may be one of the major mechanisms of SG 9R attenuation, and the possession of intact SPI-2, spvC, B, A, and R virulence genes may be associated with residual SG 9R virulence.
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Affiliation(s)
- Hyuk-Joon Kwon
- Zoonotic Disease Institute, Seoul National University, Shillim-Dong, Gwanak-Gu, Seoul, Republic of Korea.
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69
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Identification of genes that are dispensable for animal infection by Salmonella typhimurium. J Microbiol 2010; 48:399-403. [PMID: 20571960 DOI: 10.1007/s12275-010-9332-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Accepted: 01/28/2010] [Indexed: 12/17/2022]
Abstract
In the current study, we generated a pool of Salmonella typhimurium mutants using the Tn10d-cam mini-transposon. This pool of mutants was administered to BALB/c mice through the oral route, and bacteria were recovered from the spleen 3 days post-infection. After three rounds of serial passage, we observed enrichment of two insertion mutants, a yddG insertion and an amyA insertion. These two genes have been implicated in growth on plant products (amyA) and survival in the presence of paraquat (yddG), both of which are natural environments for Salmonella. Thus, while in vivo expression technology has identified S. typhimurium genes that are absolutely necessary for animal infection, other genes involved in vegetative growth also appear to play role in the establishment of pathogenesis.
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70
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Parvathi A, Vijayan J, Murali G, Chandran P. Comparative Virulence Genotyping and Antimicrobial Susceptibility Profiling of Environmental and Clinical Salmonella enterica from Cochin, India. Curr Microbiol 2010; 62:21-6. [PMID: 20490498 DOI: 10.1007/s00284-010-9665-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 04/23/2010] [Indexed: 11/26/2022]
Affiliation(s)
- Ammini Parvathi
- Molecular Biology Laboratory, National Institute of Oceanography (CSIR), Regional Centre, Dr. Salim Ali Road, Post Box No. 1913, Kochi, 682018, India.
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71
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How do bacteria sense and respond to low temperature? Arch Microbiol 2010; 192:85-95. [DOI: 10.1007/s00203-009-0539-y] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Revised: 11/19/2009] [Accepted: 12/21/2009] [Indexed: 11/30/2022]
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FUTAGAWA-SAITO K, OKATANI AT, SAKURAI-KOMADA N, BA-THEIN W, FUKUYASU T. Epidemiological Characteristics of Salmonella enterica Serovar Typhimurium from Healthy Pigs in Japan. J Vet Med Sci 2010; 72:61-6. [DOI: 10.1292/jvms.09-0041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
| | | | - Naomi SAKURAI-KOMADA
- Center for Medical Sciences, School of Health Sciences, Ibaraki Prefectural University of Health Sciences
| | - William BA-THEIN
- Department of Animal Health 2, School of Veterinary Medicine, Azabu University
- Department of Microbiology and Immunology, Shantou University Medical College
| | - Tsuguaki FUKUYASU
- Department of Animal Health 2, School of Veterinary Medicine, Azabu University
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Smith KP, George J, Cadle KM, Kumar S, Aragon SJ, Hernandez RL, Jones SE, Floyd JL, Varela MF. Elucidation of Antimicrobial Susceptibility Profiles and Genotyping of Salmonella enterica Isolates from Clinical Cases of Salmonellosis in New Mexico in 2008. World J Microbiol Biotechnol 2009; 26:1025-1031. [PMID: 20514366 DOI: 10.1007/s11274-009-0265-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
In this study, we investigated the antimicrobial susceptibility profiles and the distribution of some well known genetic determinants of virulence in clinical isolates of Salmonella enterica from New Mexico. The minimum inhibitory concentrations (MICs) for various antimicrobials were determined by using the E-test strip method according to CLSI guidelines. Virulence genotyping was performed by polymerase chain reaction (PCR) using primers specific for known virulence genes of Salmonella enterica. Of 15 isolates belonging to 11 different serovars analyzed, one isolate of Salmonella Typhimurium was resistant to multiple drugs namely ampicillin, amoxicillin / clavulanic acid, chloramphenicol and tetracycline, that also harbored class 1 intergron, bla(TEM) encoding genes for β-lactamase, chloramphenicol acetyl transferase (cat1), plus floR, tet(C) and tet(G). This strain was phage typed as DT104. PCR analysis revealed the presence of invA, hilA, stn, agfA and spvR virulence genes in all the isolates tested. The plasmid-borne pefA gene was absent in 11 isolates, while 5 isolates lacked sopE. One isolate belonging to serogroup E4 (Salmonella Sombre) was devoid of multiple virulence genes pefA, iroB, shdA and sopE. These results demonstrate that clinical Salmonella serotypes from New Mexico used here are predominantly sensitive to multiple antimicrobial agents, but vary in their virulence genotypes. Information on antimicrobial sensitivity and virulence genotypes will help in understanding the evolution and spread of epidemic strains of Salmonella enterica in the region of study.
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Affiliation(s)
- Kenneth P Smith
- Eastern New Mexico University, Department of Biology, Portales, NM, USA 88130
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74
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Chen CL, Wang CY, Chu C, Su LH, Chiu CH. Functional and molecular characterization of pSE34 encoding a type IV secretion system inSalmonella entericaserotype Enteritidis phage type 34. ACTA ACUST UNITED AC 2009; 57:274-83. [DOI: 10.1111/j.1574-695x.2009.00612.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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75
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Kingsley RA, Msefula CL, Thomson NR, Kariuki S, Holt KE, Gordon MA, Harris D, Clarke L, Whitehead S, Sangal V, Marsh K, Achtman M, Molyneux ME, Cormican M, Parkhill J, MacLennan CA, Heyderman RS, Dougan G. Epidemic multiple drug resistant Salmonella Typhimurium causing invasive disease in sub-Saharan Africa have a distinct genotype. Genome Res 2009; 19:2279-87. [PMID: 19901036 DOI: 10.1101/gr.091017.109] [Citation(s) in RCA: 418] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Whereas most nontyphoidal Salmonella (NTS) are associated with gastroenteritis, there has been a dramatic increase in reports of NTS-associated invasive disease in sub-Saharan Africa. Salmonella enterica serovar Typhimurium isolates are responsible for a significant proportion of the reported invasive NTS in this region. Multilocus sequence analysis of invasive S. Typhimurium from Malawi and Kenya identified a dominant type, designated ST313, which currently is rarely reported outside of Africa. Whole-genome sequencing of a multiple drug resistant (MDR) ST313 NTS isolate, D23580, identified a distinct prophage repertoire and a composite genetic element encoding MDR genes located on a virulence-associated plasmid. Further, there was evidence of genome degradation, including pseudogene formation and chromosomal deletions, when compared with other S. Typhimurium genome sequences. Some of this genome degradation involved genes previously implicated in virulence of S. Typhimurium or genes for which the orthologs in S. Typhi are either pseudogenes or are absent. Genome analysis of other epidemic ST313 isolates from Malawi and Kenya provided evidence for microevolution and clonal replacement in the field.
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Affiliation(s)
- Robert A Kingsley
- The Wellcome Trust Sanger Institute, The Wellcome Trust Genome Campus, Cambridge, United Kingdom.
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Genotyping, Plasmid Analysis, and Antimicrobial Susceptibility of Salmonella enterica Serotype Enteritidis Isolates from Humans and Chickens in Central Taiwan. J Formos Med Assoc 2009; 108:765-71. [DOI: 10.1016/s0929-6646(09)60403-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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77
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Chaudhuri RR, Peters SE, Pleasance SJ, Northen H, Willers C, Paterson GK, Cone DB, Allen AG, Owen PJ, Shalom G, Stekel DJ, Charles IG, Maskell DJ. Comprehensive identification of Salmonella enterica serovar typhimurium genes required for infection of BALB/c mice. PLoS Pathog 2009; 5:e1000529. [PMID: 19649318 PMCID: PMC2712085 DOI: 10.1371/journal.ppat.1000529] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Accepted: 07/06/2009] [Indexed: 01/13/2023] Open
Abstract
Genes required for infection of mice by Salmonella Typhimurium can be identified by the interrogation of random transposon mutant libraries for mutants that cannot survive in vivo. Inactivation of such genes produces attenuated S. Typhimurium strains that have potential for use as live attenuated vaccines. A quantitative screen, Transposon Mediated Differential Hybridisation (TMDH), has been developed that identifies those members of a large library of transposon mutants that are attenuated. TMDH employs custom transposons with outward-facing T7 and SP6 promoters. Fluorescently-labelled transcripts from the promoters are hybridised to whole-genome tiling microarrays, to allow the position of the transposon insertions to be determined. Comparison of microarray data from the mutant library grown in vitro (input) with equivalent data produced after passage of the library through mice (output) enables an attenuation score to be determined for each transposon mutant. These scores are significantly correlated with bacterial counts obtained during infection of mice using mutants with individual defined deletions of the same genes. Defined deletion mutants of several novel targets identified in the TMDH screen are effective live vaccines.
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Affiliation(s)
- Roy R. Chaudhuri
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Sarah E. Peters
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Stephen J. Pleasance
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Helen Northen
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Chrissie Willers
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Gavin K. Paterson
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Danielle B. Cone
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | | | | | - Gil Shalom
- Arrow Therapeutics Ltd., London, United Kingdom
| | - Dov J. Stekel
- Centre for Systems Biology, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Ian G. Charles
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Duncan J. Maskell
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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78
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Wiesner M, Zaidi MB, Calva E, Fernández-Mora M, Calva JJ, Silva C. Association of virulence plasmid and antibiotic resistance determinants with chromosomal multilocus genotypes in Mexican Salmonella enterica serovar Typhimurium strains. BMC Microbiol 2009; 9:131. [PMID: 19573249 PMCID: PMC2715408 DOI: 10.1186/1471-2180-9-131] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Accepted: 07/03/2009] [Indexed: 01/03/2023] Open
Abstract
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 backgrounds allowed us to discover genetic subgroups within the population. This study provides information about the importance of the accessory genome in generating genetic variability within a bacterial population.
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Affiliation(s)
- Magdalena Wiesner
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México.
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Pan Z, Carter B, Núñez-García J, AbuOun M, Fookes M, Ivens A, Woodward MJ, Anjum MF. Identification of genetic and phenotypic differences associated with prevalent and non-prevalent Salmonella Enteritidis phage types: analysis of variation in amino acid transport. MICROBIOLOGY-SGM 2009; 155:3200-3213. [PMID: 19574306 DOI: 10.1099/mic.0.029405-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this study, differences at the genetic level of 37 Salmonella Enteritidis strains from five phage types (PTs) were compared using comparative genomic hybridization (CGH) to assess differences between PTs. There were approximately 400 genes that differentiated prevalent (4, 6, 8 and 13a) and sporadic (11) PTs, of which 35 were unique to prevalent PTs, including six plasmid-borne genes, pefA, B, C, D, srgC and rck, and four chromosomal genes encoding putative amino acid transporters. Phenotype array studies also demonstrated that strains from prevalent PTs were less susceptible to urea stress and utilized l-histidine, l-glutamine, l-proline, l-aspartic acid, gly-asn and gly-gln more efficiently than PT11 strains. Complementation of a PT11 strain with the transporter genes from PT4 resulted in a significant increase in utilization of the amino acids and reduced susceptibility to urea stress. In epithelial cell association assays, PT11 strains were less invasive than other prevalent PTs. Most strains from prevalent PTs were better biofilm formers at 37 degrees C than at 28 degrees C, whilst the converse was true for PT11 strains. Collectively, the results indicate that genetic and corresponding phenotypic differences exist between strains of the prevalent PTs 4, 6, 8 and 13a and non-prevalent PT11 strains that are likely to provide a selective advantage for strains from the former PTs and could help them to enter the food chain and cause salmonellosis.
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Affiliation(s)
- Zhensheng Pan
- School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey TW20 0EX, UK.,Department of Food and Environmental Safety, Veterinary Laboratories Agency-Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Ben Carter
- Department of Food and Environmental Safety, Veterinary Laboratories Agency-Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Javier Núñez-García
- Department of Food and Environmental Safety, Veterinary Laboratories Agency-Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Manal AbuOun
- Department of Food and Environmental Safety, Veterinary Laboratories Agency-Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - María Fookes
- The Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Al Ivens
- The Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Martin J Woodward
- Department of Food and Environmental Safety, Veterinary Laboratories Agency-Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Muna F Anjum
- Department of Food and Environmental Safety, Veterinary Laboratories Agency-Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
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80
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Liu WQ, Feng Y, Wang Y, Zou QH, Chen F, Guo JT, Peng YH, Jin Y, Li YG, Hu SN, Johnston RN, Liu GR, Liu SL. Salmonella paratyphi C: genetic divergence from Salmonella choleraesuis and pathogenic convergence with Salmonella typhi. PLoS One 2009; 4:e4510. [PMID: 19229335 PMCID: PMC2640428 DOI: 10.1371/journal.pone.0004510] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2008] [Accepted: 12/15/2008] [Indexed: 01/13/2023] Open
Abstract
Background Although over 1400 Salmonella serovars cause usually self-limited gastroenteritis in humans, a few, e.g., Salmonella typhi and S. paratyphi C, cause typhoid, a potentially fatal systemic infection. It is not known whether the typhoid agents have evolved from a common ancestor (by divergent processes) or acquired similar pathogenic traits independently (by convergent processes). Comparison of different typhoid agents with non-typhoidal Salmonella lineages will provide excellent models for studies on how similar pathogens might have evolved. Methodologies/Principal Findings We sequenced a strain of S. paratyphi C, RKS4594, and compared it with previously sequenced Salmonella strains. RKS4594 contains a chromosome of 4,833,080 bp and a plasmid of 55,414 bp. We predicted 4,640 intact coding sequences (4,578 in the chromosome and 62 in the plasmid) and 152 pseudogenes (149 in the chromosome and 3 in the plasmid). RKS4594 shares as many as 4346 of the 4,640 genes with a strain of S. choleraesuis, which is primarily a swine pathogen, but only 4008 genes with another human-adapted typhoid agent, S. typhi. Comparison of 3691 genes shared by all six sequenced Salmonella strains placed S. paratyphi C and S. choleraesuis together at one end, and S. typhi at the opposite end, of the phylogenetic tree, demonstrating separate ancestries of the human-adapted typhoid agents. S. paratyphi C seemed to have suffered enormous selection pressures during its adaptation to man as suggested by the differential nucleotide substitutions and different sets of pseudogenes, between S. paratyphi C and S. choleraesuis. Conclusions S. paratyphi C does not share a common ancestor with other human-adapted typhoid agents, supporting the convergent evolution model of the typhoid agents. S. paratyphi C has diverged from a common ancestor with S. choleraesuis by accumulating genomic novelty during adaptation to man.
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Affiliation(s)
- Wei-Qiao Liu
- Genomics Research Center, Harbin Medical University, Harbin, China
- Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Ye Feng
- JD Watson Institute of Genome Sciences, Zhejiang University, Hangzhou, China
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Yan Wang
- Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Qing-Hua Zou
- Department of Microbiology, Peking University Health Science Center, Beijing, China
| | - Fang Chen
- Department of Microbiology, Peking University Health Science Center, Beijing, China
| | - Ji-Tao Guo
- Department of Microbiology, Peking University Health Science Center, Beijing, China
| | - Yi-Hong Peng
- Department of Microbiology, Peking University Health Science Center, Beijing, China
| | - Yan Jin
- Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Yong-Guo Li
- Depatment of Infectious Diseases, First Hospital, Harbin Medical University, Harbin, China
| | - Song-Nian Hu
- JD Watson Institute of Genome Sciences, Zhejiang University, Hangzhou, China
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Randal N. Johnston
- Departments of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
| | - Gui-Rong Liu
- Genomics Research Center, Harbin Medical University, Harbin, China
- Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- Department of Microbiology, Peking University Health Science Center, Beijing, China
- * E-mail: (G-RL); (S-LL)
| | - Shu-Lin Liu
- Genomics Research Center, Harbin Medical University, Harbin, China
- Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- Department of Microbiology, Peking University Health Science Center, Beijing, China
- Depatment of Infectious Diseases, First Hospital, Harbin Medical University, Harbin, China
- * E-mail: (G-RL); (S-LL)
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Genome expression analyses revealing the modulation of the Salmonella Rcs regulon by the attenuator IgaA. J Bacteriol 2009; 191:1855-67. [PMID: 19124574 DOI: 10.1128/jb.01604-08] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Intracellular growth attenuator A (IgaA) was identified as a Salmonella enterica regulator limiting bacterial growth inside fibroblasts. Genetic evidence further linked IgaA to repression of the RcsCDB regulatory system, which responds to envelope stress. How IgaA attenuates this system is unknown. Here, we present genome expression profiling data of S. enterica serovar Typhimurium igaA mutants grown at high osmolarity and displaying exacerbated Rcs responses. Transcriptome data revealed that IgaA attenuates gene expression changes requiring phosphorylated RcsB (RcsB~P) activity. Some RcsB-regulated genes, yciGFE and STM1862 (pagO)-STM1863-STM1864, were equally expressed in wild-type and igaA strains, suggesting a maximal expression at low levels of RcsB ~P. Other genes, such as metB, ypeC, ygaC, glnK, glnP, napA, glpA, and nirB, were shown for the first time and by independent methods to be regulated by the RcsCDB system. Interestingly, IgaA-deficient strains with reduced RcsC or RcsD levels exhibited different Rcs responses and distinct virulence properties. spv virulence genes were differentially expressed in most of the analyzed strains. spvA expression required RcsB and IgaA but, unexpectedly, was also impaired upon stimulation of the RcsC-->RcsD-->RcsB phosphorelay. Overproduction of either RcsB(+) or a nonphosphorylatable RcsB(D56Q) variant in strains displaying low spvA expression unveiled that both dephosphorylated RcsB and RcsB~P are required for optimal spvA expression. Taken together, our data support a model with IgaA attenuating the RcsCDB system by favoring the switch of RcsB~P to the dephosphorylated state. This role of IgaA in constantly fine-tuning the RcsB~P/RcsB ratio may ensure the proper expression of important virulence factors, such as the Spv proteins.
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Salmonella enterica serovar typhimurium strains with regulated delayed attenuation in vivo. Infect Immun 2008; 77:1071-82. [PMID: 19103774 DOI: 10.1128/iai.00693-08] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recombinant bacterial vaccines must be fully attenuated for animal or human hosts to avoid inducing disease symptoms while exhibiting a high degree of immunogenicity. Unfortunately, many well-studied means for attenuating Salmonella render strains more susceptible to host defense stresses encountered following oral vaccination than wild-type virulent strains and/or impair their ability to effectively colonize the gut-associated and internal lymphoid tissues. This thus impairs the ability of recombinant vaccines to serve as factories to produce recombinant antigens to induce the desired protective immunity. To address these problems, we designed strains that display features of wild-type virulent strains of Salmonella at the time of immunization to enable strains first to effectively colonize lymphoid tissues and then to exhibit a regulated delayed attenuation in vivo to preclude inducing disease symptoms. We recently described one means to achieve this based on a reversible smooth-rough synthesis of lipopolysaccharide O antigen. We report here a second means to achieve regulated delayed attenuation in vivo that is based on the substitution of a tightly regulated araC P(BAD) cassette for the promoters of the fur, crp, phoPQ, and rpoS genes such that expression of these genes is dependent on arabinose provided during growth. Thus, following colonization of lymphoid tissues, the Fur, Crp, PhoPQ, and/or RpoS proteins cease to be synthesized due to the absence of arabinose such that attenuation is gradually manifest in vivo to preclude induction of diseases symptoms. Means for achieving regulated delayed attenuation can be combined with other mutations, which together may yield safe efficacious recombinant attenuated Salmonella vaccines.
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Leucine-responsive regulatory protein (Lrp) acts as a virulence repressor in Salmonella enterica serovar Typhimurium. J Bacteriol 2008; 191:1278-92. [PMID: 19074398 DOI: 10.1128/jb.01142-08] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Leucine-responsive regulatory protein (Lrp) is a global gene regulator that influences expression of a large number of genes including virulence-related genes in Escherichia coli and Salmonella. No systematic studies examining the regulation of virulence genes by Lrp have been reported in Salmonella. We report here that constitutive expression of Lrp [lrp(Con)] dramatically attenuates Salmonella virulence while an lrp deletion (Deltalrp) mutation enhances virulence. The lrp(Con) mutant caused pleiotropic effects that include defects in invasion, cytotoxicity, and colonization, whereas the Deltalrp mutant was more proficient at these activities than the wild-type strain. We present evidence that Lrp represses transcription of key virulence regulator genes--hilA, invF, and ssrA--in Salmonella pathogenicity island 1 (SPI-1) and 2 (SPI-2), by binding directly to their promoter regions, P(hilA), P(invF), and P(ssrA). In addition, Western blot analysis showed that the expression of the SPI-1 effector SipA was reduced in the lrp(Con) mutant and enhanced in the Deltalrp mutant. Computational analysis revealed putative Lrp-binding consensus DNA motifs located in P(hilA), P(invF), and P(ssrA). These results suggest that Lrp binds to the consensus motifs and modulates expression of the linked genes. The presence of leucine enhanced Lrp binding to P(invF) in vitro and the addition of leucine to growth medium decreased the level of invF transcription. However, leucine had no effect on expression of hilA and ssrA or on cellular levels of Lrp. In addition, Lrp appears to be an antivirulence gene, since the deletion mutant showed enhanced cell invasion, cytotoxicity, and hypervirulence in BALB/c mice.
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85
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Evolution of genes on the Salmonella Virulence plasmid phylogeny revealed from sequencing of the virulence plasmids of S. enterica serotype Dublin and comparative analysis. Genomics 2008; 92:339-43. [PMID: 18718522 DOI: 10.1016/j.ygeno.2008.07.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 07/10/2008] [Accepted: 07/24/2008] [Indexed: 10/21/2022]
Abstract
Salmonella enterica serotype Dublin harbors an approximately 80-kb virulence plasmid (pSDV), which mediates systemic infection in cattle. There are two types of pSDV: one is pSDVu (pOU1113) in strain OU7025 and the other pSDVr (pOU1115) in OU7409 (SD Lane) and many clinical isolates. Sequence analysis showed that pSDVr was a recombinant plasmid (co-integrate) of pSDVu and a plasmid similar to a 35-kb indigenous plasmid (pOU1114) of S. Dublin. Most of the F-transfer region in pSDVu was replaced by a DNA segment from the pOU1114-like plasmid containing an extra replicon and a pilX operon encoding for a type IV secretion system to form pSDVr. We reconstructed the particular evolutionary history of the seven virulence plasmids of Salmonella by comparative sequence analysis. The whole evolutionary process might begin with two different F-like plasmids (IncFI and IncFII), which then incorporated the spv operon and fimbriae operon from the chromosome to form the primitive virulence plasmids. Subsequently, these plasmids descended by deletion from a relatively large plasmid to smaller ones, with some recombination events occurring over time. Our results suggest that the phylogeny of virulence plasmids as a result of frequent recombination provides the opportunity for rapid evolution of Salmonella in response to the environmental cues.
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86
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Hong SF, Chiu CH, Chu C, Feng Y, Ou JT. Complete nucleotide sequence of a virulence plasmid ofSalmonella entericaserovar Dublin and its phylogenetic relationship to the virulence plasmids of serovars Choleraesuis, Enteritidis and Typhimurium. FEMS Microbiol Lett 2008; 282:39-43. [DOI: 10.1111/j.1574-6968.2008.01096.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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87
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Nde CW, Logue CM. Characterization of antimicrobial susceptibility and virulence genes of Salmonella serovars collected at a commercial turkey processing plant. J Appl Microbiol 2008; 104:215-23. [PMID: 17850317 DOI: 10.1111/j.1365-2672.2007.03535.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
AIMS To determine the antimicrobial susceptibility profiles, distribution of class 1 integrons, virulence genes and genes encoding resistance to tetracycline (tetA, tetC, tetD and tetE) and streptomycin (strA, strB and aadA1) in Salmonella recovered from turkeys. METHODS AND RESULTS The antimicrobial susceptibility of 80 isolates was determined using National Antimicrobial Resistance Monitoring System. The distribution of resistance genes, class 1 integrons and virulence genes was determined using PCR. Resistances to tetracycline (76 x 3%) and streptomycin (40%) were common. Sixty-two (77 x 5%) isolates displayed resistance against one or more antimicrobials and 33 were multi-drug resistant. tetA was detected in 72 x 5% of the isolates, while tetC, tetD and tetE were not detected. The strA and strB genes were detected in 73 x 8% of the isolates. Two isolates possessed class 1 integrons of 1 kb in size, containing the aadA1 gene conferring resistance to streptomycin and spectinomycin. Fourteen of the virulence genes were detected in over 80% of the isolates. CONCLUSIONS This study shows that continuous use of tetracycline and streptomycin in poultry production selects for resistant strains. The Salmonella isolates recovered possess significant ability to cause human illness. SIGNIFICANCE AND IMPACT OF THE STUDY Information from this study can be employed in guiding future strategies for the use of antimicrobials in poultry production.
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Affiliation(s)
- C W Nde
- Department of Veterinary and Microbiological Sciences, The Great Plains Institute of Food Safety, North Dakota State University, Fargo, ND 58105, USA
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88
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Foley SL, Lynne AM. Food animal-associated Salmonella challenges: Pathogenicity and antimicrobial resistance1. J Anim Sci 2008; 86:E173-87. [PMID: 17878285 DOI: 10.2527/jas.2007-0447] [Citation(s) in RCA: 216] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Salmonellosis is a worldwide health problem; Salmonella infections are the second leading cause of bacterial foodborne illness in the United States. Approximately 95% of cases of human salmonellosis are associated with the consumption of contaminated products such as meat, poultry, eggs, milk, seafood, and fresh produce. Salmonella can cause a number of different disease syndromes including gastroenteritis, bacteremia, and typhoid fever, with the most common being gastroenteritis, which is often characterized by abdominal pain, nausea, vomiting, diarrhea, and headache. Typically the disease is self-limiting; however, with more severe manifestations such as bacteremia, antimicrobial therapy is often administered to treat the infection. Currently, there are over 2,500 identified serotypes of Salmonella. A smaller number of these serotypes are significantly associated with animal and human disease including Typhimurium, Enteritidis, Newport, Heidelberg, and Montevideo. Increasingly, isolates from these serotypes are being detected that demonstrate resistance to multiple antimicrobial agents, including third-generation cephalosporins, which are recommended for the treatment of severe infections. Many of the genes that encode resistance are located on transmissible elements such as plasmids that allow for potential transfer of resistance among strains. Plasmids are also known to harbor virulence factors that contribute to Salmonella pathogenicity. Several serotypes of medical importance, including Typhimurium, Enteritidis, Newport, Dublin, and Choleraesuis, are known to harbor virulence plasmids containing genes that code for fimbriae, serum resistance, and other factors. Additionally, many Salmonella contain pathogenicity islands scattered throughout their genomes that encode factors essential for bacterial adhesion, invasion, and infection. Salmonella have evolved several virulence and antimicrobial resistance mechanisms that allow for continued challenges to our public health infrastructure.
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Affiliation(s)
- S L Foley
- National Farm Medicine Center, Marshfield Clinic Research Foundation, Marshfield, WI 54449, USA.
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89
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Kishima M, Uchida I, Namimatsu T, Osumi T, Takahashi S, Tanaka K, Aoki H, Matsuura K, Yamamoto K. Nationwide Surveillance of salmonella in the Faeces of Pigs in Japan. Zoonoses Public Health 2008; 55:139-44. [DOI: 10.1111/j.1863-2378.2007.01105.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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90
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Mazurkiewicz P, Thomas J, Thompson JA, Liu M, Arbibe L, Sansonetti P, Holden DW. SpvC is a Salmonella effector with phosphothreonine lyase activity on host mitogen-activated protein kinases. Mol Microbiol 2008; 67:1371-83. [PMID: 18284579 PMCID: PMC2268955 DOI: 10.1111/j.1365-2958.2008.06134.x] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
SpvC is encoded by the Salmonella virulence plasmid. We have investigated the biochemical function of SpvC and the mechanism by which it is secreted by bacteria and translocated into infected macrophages. We constructed a strain carrying a deletion in spvC and showed that the strain is attenuated for systemic virulence in mice. SpvC can be secreted in vitro by either the SPI-1 or SPI-2 type III secretion systems. Cell biological and genetic experiments showed that translocation of the protein into the cytosol of macrophages by intracellular bacteria is dependent on the SPI-2 T3SS. Using antibodies specific to phospho-amino acids and mass spectrometry we demonstrate that SpvC has phosphothreonine lyase activity on full-length phospho-Erk (pErk) and a synthetic 13-amino-acid phospho-peptide containing the TXY motif. A Salmonella strain expressing spvC from a plasmid downregulated cytokine release from infected cells.
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Affiliation(s)
- Piotr Mazurkiewicz
- Centre for Molecular Microbiology and Infection, Imperial College London, Armstrong Road, London SW7 2AZ, UK
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91
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Bueno SM, González PA, Carreño LJ, Tobar JA, Mora GC, Pereda CJ, Salazar-Onfray F, Kalergis AM. The capacity of Salmonella to survive inside dendritic cells and prevent antigen presentation to T cells is host specific. Immunology 2008; 124:522-33. [PMID: 18266715 DOI: 10.1111/j.1365-2567.2008.02805.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Infection with Salmonella enterica serovar Typhimurium (S. Typhimurium) causes a severe and lethal systemic disease in mice, characterized by poor activation of the adaptive immune response against Salmonella-derived antigens. Recently, we and others have reported that this feature relies on the ability of S. Typhimurium to survive within murine dendritic cells (DCs) and avoid the presentation of bacteria-derived antigens to T cells. In contrast, here we show that infection of murine DCs with either S. Typhi or S. Enteritidis, two serovars adapted to different hosts, leads to an efficient T-cell activation both in vitro and in vivo. Accordingly, S. Typhi and S. Enteritidis failed to replicate within murine DCs and were quickly degraded, allowing T-cell activation. In contrast, human DCs were found to be permissive for survival and proliferation of S. Typhi, but not for S. Typhimurium or S. Enteritidis. Our data suggest that Salmonella host restriction is characterized by the ability of these bacteria to survive within DCs and avoid activation of the adaptive immune response in their specific hosts.
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Affiliation(s)
- Susan M Bueno
- Millennium Nucleus on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
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92
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Characterisation of Salmonella enterica serotype Typhimurium isolates from wild birds in northern England from 2005 - 2006. BMC Vet Res 2008; 4:4. [PMID: 18230128 PMCID: PMC2257933 DOI: 10.1186/1746-6148-4-4] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Accepted: 01/29/2008] [Indexed: 11/29/2022] Open
Abstract
Background Several studies have shown that a number of serovars of Salmonella enterica may be isolated from wild birds, and it has been suggested that wild birds may play a role in the epidemiology of human and livestock salmonellosis. However, little is known about the relationship between wild bird S. enterica strains and human- and livestock- associated strains in the United Kingdom. Given the zoonotic potential of salmonellosis, the main aim of this study was to investigate the molecular epidemiology of S. enterica infections in wild birds in the north of England and, in particular, to determine if wild bird isolates were similar to those associated with disease in livestock or humans. Results Thirty two Salmonella enterica isolates were collected from wild birds in northern England between February 2005 and October 2006, of which 29 were S. enterica serovar Typhimurium (S. Typhimurium); one S. Newport, one S. Senftenberg, and one isolate could not be classified by serotyping. Further analysis through phage typing and macro-restriction pulsed-field gel electrophoresis indicated that wild passerine deaths associated with salmonellosis were caused by closely-related S. Typhimurium isolates, some of which were clonal. These isolates were susceptible to all antimicrobials tested, capable of invading and persisting within avian macrophage-like HD11 cells in vitro, and contained a range of virulence factors associated with both systemic and enteric infections of birds and mammals. However, all the isolates lacked the sopE gene associated with some human and livestock disease outbreaks caused by S. Typhimurium. Conclusion The wild bird isolates of S. enterica characterised in this investigation may not represent a large zoonotic risk. Molecular characterisation of isolates suggested that S. Typhimurium infection in wild passerines is maintained within wild bird populations and the causative strains may be host-adapted.
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93
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Conjugal transfer of the Salmonella enterica virulence plasmid in the mouse intestine. J Bacteriol 2008; 190:1922-7. [PMID: 18178735 DOI: 10.1128/jb.01626-07] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
BALB/c mice were infected with two Salmonella enterica serovar Typhimurium strains, one of which lacked the virulence plasmid. Transconjugants were found at high frequencies in the mouse feces and at low frequencies in the liver and the spleen, suggesting that mating occurred in the gut. Laboratory conditions that mimic those of the small intestine (microaerophilic growth in the presence of 0.3 M NaCl) increased the frequency of virulence plasmid transfer. Sodium deoxycholate, which is found at high concentrations in the duodenum, and sodium propionate, which is abundant in the large intestine, reduced the conjugation frequency. Feces inhibited conjugation. Altogether, these observations suggested that transfer of the virulence plasmid occurred in the distal portion of the small intestine. Conjugation trials in ileal loops provided direct evidence that conjugal transfer of the Salmonella virulence plasmid occurs in the ileum in mice.
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94
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Prevalence and characterization of multidrug-resistant (type ACSSuT) Salmonella enterica serovar Typhimurium strains in isolates from four gosling farms and a hatchery farm. J Clin Microbiol 2007; 46:522-6. [PMID: 18077649 DOI: 10.1128/jcm.00709-07] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica serovar Typhimurium strains of phage types DT104 and U302 are often resistant to ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline (the ACSSuT resistance type) and are major zoonotic pathogens. Increased consumption of goose meat may enhance the risk of transferring S. enterica serovar Typhimurium and other enteric pathogens from geese to human due to the consumption of meats from infected geese or improper preparation of meats. Therefore, we characterized S. enterica serovar Typhimurium strains isolated from four goose farms (farms A, B, C, and D) and one hatchery farm (farm E) to determine the epidemic and genetic differences among them. Antibiotic susceptibility tests and multiplex PCR confirmed that 77.6% (52/67) of strains were ACSSuT strains isolated from farms A, C, and E. Antibiotic-susceptible strains were isolated mostly from farm B, and no strain was observed in farm D. All ACSSuT strains harbored a 94.7-kb virulence plasmid and contained one 1.1-kb conserved segment identical to that of Salmonella genomic island 1. Four genotypes were determined among these S. enterica serovar Typhimurium isolates by pulsed-field gel electrophoresis analysis of XbaI-digested DNA fragments. Most isolates (85.29%; 29/34) of major genotype Ib were ACSSuT strains isolated mainly from goslings of farm C and egg membranes of farm E, a hatchery farm, suggesting that S. enterica serovar Typhimurium strains in isolates from goslings might originate from its hatchery, from the egg membranes to the gosling fluff after hatching. Multiple phage types, types 8, 12, U283, DT104, and U302, were identified. In conclusion, geese were a reservoir of diverse multidrug-resistant (type ACSSuT) S. enterica serovar Typhimurium strains, and each farm was colonized with genetically closely related S. enterica serovar Typhimurium strains.
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95
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Foley SL, Zhao S, Walker RD. Comparison of molecular typing methods for the differentiation of Salmonella foodborne pathogens. Foodborne Pathog Dis 2007; 4:253-76. [PMID: 17883310 DOI: 10.1089/fpd.2007.0085] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Bacteria belonging to the genus Salmonella are among the leading causes of foodborne disease of bacterial etiology. These bacteria are also widely disseminated throughout the animal kingdom. The ability to identify the food source from which a human pathogen originated would be of great value in reducing the incidence of foodborne disease and the extent of disease outbreaks due to Salmonella. To date, efforts to identify the origin of these pathogens have centered on phenotypic and genotypic characterization of Salmonella isolates. This review focuses molecular or genotypic techniques that are currently being used for typing, and examines their strengths and weaknesses for determining the source of Salmonella foodborne infections.
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Affiliation(s)
- Steven L Foley
- National Farm Medicine Center, Marshfield Clinic Research Foundation, Marshfield, Wisconsin 54449, USA.
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96
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Logue CM, Nde CW. SalmonellaContamination of Turkey from Processing to Final Product—A Process to Product Perspective. Foodborne Pathog Dis 2007; 4:491-504. [DOI: 10.1089/fpd.2007.0006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Catherine M. Logue
- Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, North Dakota
| | - Chantal W. Nde
- Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, North Dakota
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97
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Heithoff DM, Badie G, Julio SM, Enioutina EY, Daynes RA, Sinsheimer RL, Mahan MJ. In vivo-selected mutations in methyl-directed mismatch repair suppress the virulence attenuation of Salmonella dam mutant strains following intraperitoneal, but not oral, infection of naïve mice. J Bacteriol 2007; 189:4708-17. [PMID: 17468250 PMCID: PMC1913454 DOI: 10.1128/jb.00299-07] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Accepted: 04/18/2007] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica serovar Typhimurium that lacks the DNA adenine methylase (Dam) ectopically expresses multiple genes that are preferentially expressed during infection, is attenuated for virulence, and confers heightened immunity in vaccinated hosts. The safety of dam mutant Salmonella vaccines was evaluated by screening within infected mice for isolates that have an increased capacity to cause disease relative to the attenuated parental strain. Since dam mutant strains are sensitive to the DNA base analog 2-aminopurine (2-AP), we screened for 2-AP-resistant (2-AP(r)) isolates in systemic tissues of mice infected with dam mutant Salmonella. Such 2-AP(r) derivatives were isolated following intraperitoneal but not oral administration and were shown to be competent for infectivity via intraperitoneal but not oral infection of naïve mice. These 2-AP(r) derivatives were deficient in methyl-directed mismatch repair and were resistant to nitric oxide, yet they retained the bile-sensitive phenotype of the parental dam mutant strain. Additionally, introduction of a mutH null mutation into dam mutant cells suppressed the inherent defects in intraperitoneal infectivity and nitric oxide resistance, as well as overexpression of SpvB, an actin cytotoxin required for Salmonella systemic survival. These data suggest that restoration of intraperitoneal virulence of dam mutant strains is associated with deficiencies in methyl-directed mismatch repair that correlate with the production of systemically related virulence functions.
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Affiliation(s)
- Douglas M Heithoff
- Department of Molecular, Cellular and Developmental Biology, University of California-Santa Barbara, CA 93106, USA
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98
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Bessa MC, Michael GB, Canu N, Canal CW, Cardoso M, Rabsch W, Rubino S. Phenotypic and genetic characterization of Salmonella enterica subsp. enterica serovar Typhimurium isolated from pigs in Rio Grande do Sul, Brazil. Res Vet Sci 2007; 83:302-10. [PMID: 17336354 DOI: 10.1016/j.rvsc.2007.01.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Revised: 01/03/2007] [Accepted: 01/12/2007] [Indexed: 11/21/2022]
Abstract
This study aimed to investigate the relatedness of porcine Salmonella enterica subsp. enterica (S.) serovar Typhimurium strains isolated in Southern Brazil. Sixty-six isolates from pigs belonging to three commercial companies were submitted to phage typing, XbaI-macrorestriction (PFGE), IS200 hybridization, rep-PCR, antimicrobial susceptibility testing, and PCR assay targeting the spvR region. All strains presented a unique rep-PCR pattern and 63 strains had a common IS200 profile. One pulse-type (XA) was the most prevalent (39/66 strains) and included strains of phage types DT177, DT192, DT194 and RDNC. The spvR region was detected in three strains, which harboured plasmids of 90 kb. High rates of tetracycline, sulfonamide and streptomycin resistance were found. Isolates from farms located in different geographic regions but associated to the same commercial companies clustered together and presented a common resistance profile. Results suggested that clonal groups of S. Typhimurium are present in pig commercial companies in Southern Brazil.
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Affiliation(s)
- Marjo Cado Bessa
- Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, UFRGS, Av. Bento Gonçalves 9090, 90540-000 Porto Alegre, RS, Brazil
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99
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Boyle EC, Bishop JL, Grassl GA, Finlay BB. Salmonella: from pathogenesis to therapeutics. J Bacteriol 2006; 189:1489-95. [PMID: 17189373 PMCID: PMC1855715 DOI: 10.1128/jb.01730-06] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Erin C Boyle
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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100
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Chiu CH, Su LH, Chu CH, Wang MH, Yeh CM, Weill FX, Chu C. Detection of multidrug-resistant Salmonella enterica serovar typhimurium phage types DT102, DT104, and U302 by multiplex PCR. J Clin Microbiol 2006; 44:2354-8. [PMID: 16825349 PMCID: PMC1489530 DOI: 10.1128/jcm.00171-06] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica serovar Typhimurium is a common cause of nontyphoidal salmonellosis in humans and animals. Multidrug-resistant serovar Typhimurium phage type DT104, which emerged in the 1990s, has become widely distributed in many countries. A total of 104 clinical isolates of Salmonella serogroup B were collected from three major hospitals in Taiwan during 1997 to 2003 and were examined by a multiplex PCR targeting the resistance genes and the spv gene of the virulence plasmid. A total of 51 isolates (49%) were resistant to all drugs (ACSSuT [resistance to ampicillin, chloramphenicol, streptomycin, sulfonamide, and tetracycline]), and all contained a 1.25-kb PCR fragment of integron that is part of the 43-kb Salmonella genomic island 1 (SGI1). The second group was resistant to SSu (28%), and the third was susceptible to all five drugs (13%). Fifty-nine isolates were serotyped to be serovar Typhimurium by the tube agglutination method using H antisera. The virulence plasmid was found in 54 (91.5%) of the 59 serovar Typhimurium isolates. A majority (94.1%) of the Salmonella serogroup B isolates with the ACSSuT resistance pattern harbored a virulence plasmid. Phage typing identified three major phage types: DT104, DT120, and U302. Analysis of the isolates by pulsed-field gel electrophoresis showed six genotypes. We found two genotypes in DT104 strains, two in DT120, and the other two in U302. The presence of a monophasic serovar (4,5,12:i:-) has added difficulty in the determination of the serovars of multidrug-resistant Salmonella serogroup B isolates. Nevertheless, the multiplex PCR devised in the present study appears to be efficient and useful in the rapid identification of ACSSuT-type serovar Typhimurium with SGI1, irrespective of their phage types.
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Affiliation(s)
- Cheng-Hsun Chiu
- Department of Pediatrics, Chang Gung Children's Hospital, and Chang Gung University College of Medicine, Taoyuan, Taiwan
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