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Dewaele I, Rasschaert G, Wildemauwe C, Van Meirhaeghe H, Vanrobaeys M, De Graef E, Herman L, Ducatelle R, Heyndrickx M, De Reu K. Polyphasic characterization of Salmonella Enteritidis isolates on persistently contaminated layer farms during the implementation of a national control program with obligatory vaccination: A longitudinal study. Poult Sci 2012; 91:2727-35. [DOI: 10.3382/ps.2012-02218] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Campos J, Pichel M, Vaz T, Tavechio A, Fernandes S, Muñoz N, Rodriguez C, Realpe M, Moreno J, Araya P, Fernández J, Fernández A, Campos E, Duarte F, Gustafson NW, Binsztein N, Gutierrez EP. Building PulseNet Latin America and Caribbean Salmonella regional database: First conclusions of genetic subtypes of S. Typhi, S. Typhimurium and S. Enteritidis circulating in six countries of the region. Food Res Int 2012. [DOI: 10.1016/j.foodres.2011.10.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Cho S, Whittam T, Boxrud D, Bartkus J, Rankin S, Wilkins M, Somsel P, Downes F, Musser K, Root T, Warnick L, Wiedmann M, Saeed A. Use of multiple‐locus variable number tandem repeat analysis and phage typing for subtyping of
Salmonella
Enteritidis from sporadic human cases in the United States. J Appl Microbiol 2010; 108:859-867. [DOI: 10.1111/j.1365-2672.2009.04492.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S. Cho
- National Food Safety and Toxicology Center, Michigan State University, East Lansing, MI, USA
| | - T.S. Whittam
- National Food Safety and Toxicology Center, Michigan State University, East Lansing, MI, USA
| | - D.J. Boxrud
- Minnesota Department of Health, St. Paul, MN, USA
| | - J.M. Bartkus
- Minnesota Department of Health, St. Paul, MN, USA
| | - S.C. Rankin
- University of Pennsylvania, Philadelphia, PA, USA
| | - M.J. Wilkins
- Michigan Department of Community Health, Lansing, MI, USA
| | - P. Somsel
- Michigan Department of Community Health, Lansing, MI, USA
| | - F.P. Downes
- Michigan Department of Community Health, Lansing, MI, USA
| | - K.A. Musser
- New York State Department of Health, Albany, NY, USA
| | - T.P. Root
- New York State Department of Health, Albany, NY, USA
| | | | | | - A.M. Saeed
- National Food Safety and Toxicology Center, Michigan State University, East Lansing, MI, USA
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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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Pavlic M, Griffiths MW. Principles, Applications, and Limitations of Automated Ribotyping as a Rapid Method in Food Safety. Foodborne Pathog Dis 2009; 6:1047-55. [DOI: 10.1089/fpd.2009.0264] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Marin Pavlic
- Department of Food Science, University of Guelph, Guelph, Ontario, Canada
| | - Mansel W. Griffiths
- Department of Food Science, University of Guelph, Guelph, Ontario, Canada
- Canadian Research Institute for Food Safety, University of Guelph, Guelph, Ontario, Canada
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Kalender H, Şen S, Hasman H, Hendriksen RS, Aarestrup FM. Antimicrobial Susceptibilities, Phage Types, and Molecular Characterization ofSalmonella entericaSerovar Enteritidis from Chickens and Chicken Meat in Turkey. Foodborne Pathog Dis 2009; 6:265-71. [DOI: 10.1089/fpd.2008.9989] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Hakan Kalender
- Veterinary Control and Research Institute, Elazığ, Turkey
| | - Selahattin Şen
- Central Veterinary Control and Research Institute, Ankara, Turkey
| | - Henrik Hasman
- Community Reference Laboratory for Antimicrobial Resistance and WHO Collaborating Centre for Antimicrobial Resistance in Foodborne Pathogens, National Food Institute, Technical University of Denmark, Copenhagen, Denmark
| | - Rene S. Hendriksen
- Community Reference Laboratory for Antimicrobial Resistance and WHO Collaborating Centre for Antimicrobial Resistance in Foodborne Pathogens, National Food Institute, Technical University of Denmark, Copenhagen, Denmark
| | - Frank M. Aarestrup
- Community Reference Laboratory for Antimicrobial Resistance and WHO Collaborating Centre for Antimicrobial Resistance in Foodborne Pathogens, National Food Institute, Technical University of Denmark, Copenhagen, Denmark
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Cho S, Whittam TS, Boxrud DJ, Bartkus JM, Saeed AM. Allele distribution and genetic diversity of VNTR loci in Salmonella enterica serotype Enteritidis isolates from different sources. BMC Microbiol 2008; 8:146. [PMID: 18793420 PMCID: PMC2561042 DOI: 10.1186/1471-2180-8-146] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Accepted: 09/15/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Salmonella enterica serotype Enteritidis (S. Enteritidis) is a zoonotic pathogen, which can be found in many sources including animals and the environment. However, little is known about the molecular relatedness among S. Enteritidis isolates from different sources. We have applied multiple-locus variable number tandem repeat analysis (MLVA) to study the genetic diversity of S. Enteritidis isolates from human and non-human sources. RESULTS We identified 38 unique MLVA types using nine VNTR loci markers for discrimination between 145 S. Enteritidis isolates from different sources including humans (n = 41), chickens (n = 45), and eggs (n = 40). There were 20 distinct MLVA types identified from human isolates, 17 distinct MLVA types from chicken isolates, and 5 from egg isolates. We compared allele distribution and frequency for each VNTR marker and measured allelic polymorphism within each VNTR locus of S. Enteritidis isolates from the sources using Nei's diversity index (D). Differences in allele distribution and frequency were detected in most loci of study isolates. Different genetic diversity for certain loci was identified in isolates from different sources. The average of genetic diversity (D) was lower in egg isolates (0.16) compared to human (0.41) and chicken (0.30). However, for loci SE3, SE7, and SE9, human isolates showed significantly higher diversity than both chicken and egg isolates. Whereas for loci SE5 and SE10, chicken isolates had significantly higher diversity than both human and egg isolates. Minimum-spanning tree (MST) comprised one major cluster, a minor cluster, and four clonal expansions. MLVA application enabled a cluster analysis by the MST of the S. Enteritidis isolates by sources, which allows a great insight into the genetic relatedness and the possible flow of these organisms between different reservoirs and humans. CONCLUSION Differences in allele distribution and genetic diversity of VNTR loci in S. Enteritidis isolates from different sources were found. Polymorphism in most of the VNTR loci was more frequent among human S. Enteritidis isolates than isolates from chickens or eggs. Therefore, VNTR profiles of S. Enteritidis isolates from a specific source should be further evaluated as potential markers in epidemiologic investigations to trace S. Enteritidis to their probable source.
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Affiliation(s)
- Seongbeom Cho
- National Food Safety and Toxicology Center, Michigan State University, East Lansing, MI, USA.
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Cho S, Boxrud DJ, Bartkus JM, Whittam TS, Saeed M. Multiple-locus variable-number tandem repeat analysis of Salmonella Enteritidis isolates from human and non-human sources using a single multiplex PCR. FEMS Microbiol Lett 2007; 275:16-23. [PMID: 17692097 PMCID: PMC2040188 DOI: 10.1111/j.1574-6968.2007.00875.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Simplified multiple-locus variable-number tandem repeat analysis (MLVA) was developed using one-shot multiplex PCR for seven variable-number tandem repeats (VNTR) markers with high diversity capacity. MLVA, phage typing, and PFGE methods were applied on 34 diverse Salmonella Enteritidis isolates from human and non-human sources. MLVA detected allelic variations that helped to classify the S. Enteritidis isolates into more evenly distributed subtypes than other methods. MLVA-based S. Enteritidis clonal groups were largely associated with sources of the isolates. Nei's diversity indices for polymorphism ranged from 0.25 to 0.70 for seven VNTR loci markers. Based on Simpson's and Shannon's diversity indices, MLVA had a higher discriminatory power than pulsed field gel electrophoresis (PFGE), phage typing, or multilocus enzyme electrophoresis. Therefore, MLVA may be used along with PFGE to enhance the effectiveness of the molecular epidemiologic investigation of S. Enteritidis infections.
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Affiliation(s)
- Seongbeom Cho
- Department of Large Animal Sciences and Epidemiology, and National Food Safety and Toxicology Center, Michigan State UniversityEast Lansing, MI, USA
| | - David J Boxrud
- Department of Large Animal Sciences and Epidemiology, and National Food Safety and Toxicology Center, Minnesota Department of HealthSt Paul, MN, USA
| | - Joanne M Bartkus
- Department of Large Animal Sciences and Epidemiology, and National Food Safety and Toxicology Center, Minnesota Department of HealthSt Paul, MN, USA
| | - Thomas S Whittam
- Department of Large Animal Sciences and Epidemiology, and National Food Safety and Toxicology Center, Michigan State UniversityEast Lansing, MI, USA
| | - Mahdi Saeed
- Department of Large Animal Sciences and Epidemiology, and National Food Safety and Toxicology Center, Michigan State UniversityEast Lansing, MI, USA
- Department of Large Animal Sciences and Epidemiology, and National Food Safety and Toxicology Center, Minnesota Department of HealthSt Paul, MN, USA
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Santos FBO, Dsouza DH, Jaykus L, Ferket PR, Sheldon BW. Genotypes, serotypes, and antibiotic resistance profiles of Salmonella isolated from commercial North Carolina turkey farms. J Food Prot 2007; 70:1328-33. [PMID: 17612059 DOI: 10.4315/0362-028x-70.6.1328] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study was designed to determine the serotypes, genotypes, and antibiotic resistance (AbR) patterns of 42 Salmonella isolates recovered from either fecal or litter samples of 12 commercial turkey farms across two seasons (summer and winter) and two ages (3 and 19 weeks). Isolates were serotyped on the basis of the Kauffmann-White scheme. Genotyping was done by restriction digestion of cDNA (XbaI) and subsequent pulsed-field gel electrophoresis (PFGE). The AbR was determined with Sensititre susceptibility plates. Serovar Kentucky was the most prevalent serotype (26%), followed by Senftenberg (19%), Muenster (17%), Mbandaka (10%), Javiana (7%), Hadar (5%), Heidelberg (5%), 8,(20):nonmotile (5%), Agona (2%), Infantis (2%), and 4,12:r:-(2%). Serovars Kentucky, Heidelberg, Hadar, and 8,(20):nonmotile were isolated only from the 19-week-old bird samples, whereas Senftenberg and Muenster were isolated only from the young birds (3 weeks old). Isolates within any one serotype showed minor PFGE banding pattern differences, but dendogram analysis indicated that sequence variability between serotypes was more significant than within serotypes. Isolates were resistant to tetracycline (86%), sulfisoxazole (71%), streptomycin (64%), gentamicin (41%), ampicillin (36%), kanamycin (26%), sulfamethoxazole-trimethoprim (7%), nalidixic acid (5%), cefoxitin (2%), and ceftiofur (2%). One isolate (Muenster) was resistant to nine antibiotics (2%), and the others were resistant to six (7%), five (12%), four (10%), three (21%), two (24%), and one (10%) antibiotic. Only two isolates (5%) were susceptible to all antibiotics tested. The AbR patterns were affected by age; on average, strains recovered from young birds were resistant to more than four drugs compared with fewer than three in older birds (P < 0.05). This study showed that Salmonella enterica subsp. enterica serotypes, genotypes and AbR patterns were affected by bird age but not by season or farm.
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Affiliation(s)
- F B O Santos
- Department of Poultry Science , North Carolina State University, Raleigh, North Carolina 27695, USA
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Morales CA, Musgrove M, Humphrey TJ, Cates C, Gast R, Guard-Bouldin J. Pathotyping of Salmonella enterica by analysis of single-nucleotide polymorphisms in cyaA and flanking 23S ribosomal sequences. Environ Microbiol 2007; 9:1047-59. [PMID: 17359275 DOI: 10.1111/j.1462-2920.2006.01233.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The egg-contaminating phenotype of Salmonella enterica serotype Enteritidis was linked to single-nucleotide polymorphisms (SNPs) occurring in cyaA, which encodes adenylate cyclase that produces cAMP and pyrophosphate from ATP. Ribotyping indicated that SNPs in cyaA were linked to polymorphisms occurring in the rrlC and rrlA 23S ribosomal subunits. Phylogenetic analysis of cyaA discriminated between Salmonella enterica serotypes and within serotype Enteritidis. Serotypes Typhimurium, Heidelberg and Enteritidis produced one, three and six cyaA allelic variants, respectively, among the set of 56 isolates examined. Asparagine(702) of CyaA was converted to serine in a biofilm-producing isolate. Statistical analysis was applied to 42 other genes encoding proteins between 800 and 1000 amino acids (aa). Results show that the 848 aa CyaA of serovar Enteritidis evolved by nucleotide substitutions that did not significantly alter the purine-to-pyrimidine nucleotide substitution ratio, which was a characteristic of large genes that was positively correlated with increasing gene size. In summary, these analyses link SNPs occurring in the rrlC-rrlA genomic fragment of S. enterica to genetic drift within S. Enteritidis that is associated with egg contamination.
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Affiliation(s)
- Cesar A Morales
- Egg Safety and Quality Research Unit, Agricultural Research Service, United States Department of Agriculture, Athens, GA 30605, USA
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Porwollik S, Santiviago CA, Cheng P, Florea L, Jackson S, McClelland M. Differences in gene content between Salmonella enterica serovar Enteritidis isolates and comparison to closely related serovars Gallinarum and Dublin. J Bacteriol 2005; 187:6545-55. [PMID: 16159788 PMCID: PMC1236623 DOI: 10.1128/jb.187.18.6545-6555.2005] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica serovar Enteritidis is often transmitted into the human food supply through eggs of hens that appear healthy. This pathogen became far more prevalent in poultry following eradication of the fowl pathogen S. enterica serovar Gallinarum in the mid-20th century. To investigate whether changes in serovar Enteritidis gene content contributed to this increased prevalence, and to evaluate genetic heterogeneity within the serovar, comparative genomic hybridization was performed on eight 60-year-old and nineteen 10- to 20-year-old serovar Enteritidis strains from various hosts, using a Salmonella-specific microarray. Overall, almost all the serovar Enteritidis genomes were very similar to each other. Excluding two rare strains classified as serovar Enteritidis in the Salmonella reference collection B, only eleven regions of the serovar Enteritidis phage type 4 (PT4) chromosome (sequenced at the Sanger Center) were absent or divergent in any of the other serovar Enteritidis strains tested. The more recent isolates did not have consistent differences from 60-year-old field isolates, suggesting that no large genomic additions on a whole-gene scale were needed for serovar Enteritidis to become more prevalent in domestic fowl. Cross-hybridization of phage genes on the array with related genes in the examined genomes grouped the serovar Enteritidis isolates into two major lineages. Microarray comparisons of the sequenced serovar Enteritidis PT4 to isolates of the closely related serovars Dublin and Gallinarum (biovars Gallinarum and Pullorum) revealed several genomic areas that distinguished them from serovar Enteritidis and from each other. These differences in gene content could be useful in DNA-based typing and in understanding the different phenotypes of these related serovars.
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Affiliation(s)
- S Porwollik
- Sidney Kimmel Cancer Center, 10835 Road to the Cure, San Diego, California 92121, USA
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Morales CA, Porwollik S, Frye JG, Kinde H, McClelland M, Guard-Bouldin J. Correlation of phenotype with the genotype of egg-contaminating Salmonella enterica serovar Enteritidis. Appl Environ Microbiol 2005; 71:4388-99. [PMID: 16085829 PMCID: PMC1183325 DOI: 10.1128/aem.71.8.4388-4399.2005] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Accepted: 02/21/2005] [Indexed: 01/01/2023] Open
Abstract
The genotype of Salmonella enterica serovar Enteritidis was correlated with the phenotype using DNA-DNA microarray hybridization, ribotyping, and Phenotype MicroArray analysis to compare three strains that differed in colony morphology and phage type. No DNA hybridization differences were found between two phage type 13A (PT13A) strains that varied in biofilm formation; however, the ribotype patterns were different. Both PT13A strains had DNA sequences similar to that of bacteriophage Fels2, whereas the PT4 genome to which they were compared, as well as a PT4 field isolate, had a DNA sequence with some similarity to the bacteriophage ST64b sequence. Phenotype MicroArray analysis indicated that the two PT13A strains and the PT4 field isolate had similar respiratory activity profiles at 37 degrees C. However, the wild-type S. enterica serovar Enteritidis PT13A strain grew significantly better in 20% more of the 1,920 conditions tested when it was assayed at 25 degrees C than the biofilm-forming PT13A strain grew. Statistical analysis of the respiratory activity suggested that S. enterica serovar Enteritidis PT4 had a temperature-influenced dimorphic metabolism which at 25 degrees C somewhat resembled the profile of the biofilm-forming PT13A strain and that at 37 degrees C the metabolism was nearly identical to that of the wild-type PT13A strain. Although it is possible that lysogenic bacteriophage alter the balance of phage types on a farm either by lytic competition or by altering the metabolic processes of the host cell in subtle ways, the different physiologies of the S. enterica serovar Enteritidis strains correlated most closely with minor, rather than major, genomic changes. These results strongly suggest that the pandemic of egg-associated human salmonellosis that came into prominence in the 1980s is primarily an example of bacterial adaptive radiation that affects the safety of the food supply.
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Affiliation(s)
- Cesar A Morales
- Egg Safety and Quality Research Unit, Agricultural Research Service, U.S. Department of Agriculture, 950 College Station Rd., Athens, GA 30605, USA
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Guard-Bouldin J, Gast RK, Humphrey TJ, Henzler DJ, Morales C, Coles K. Subpopulation characteristics of egg-contaminating Salmonella enterica serovar Enteritidis as defined by the lipopolysaccharide O chain. Appl Environ Microbiol 2004; 70:2756-63. [PMID: 15128529 PMCID: PMC404386 DOI: 10.1128/aem.70.5.2756-2763.2004] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Characterization of Salmonella enterica serovar Enteritidis was refined by incorporating new data from isolates obtained from avian sources, from the spleens of naturally infected mice, and from the United Kingdom into an existing lipopolysaccharide (LPS) O-chain compositional database. From least to greatest, the probability of avian isolates producing high-molecular-mass LPS O chain ranked as follows: pooled kidney, liver, and spleen; intestine; cecum; ovary and oviduct; albumen; yolk; and whole egg. Mouse isolates were most like avian intestinal samples, whereas United Kingdom isolates were most like those from the avian reproductive tract and egg. Non-reproductive tract organ isolates had significant loss of O chain. Isogenic isolates that varied in ability to make biofilm and to be orally invasive produced different O-chain structures at 25 degrees C but not at 37 degrees C. Hens infected at a 91:9 biofilm-positive/-negative colony phenotype ratio yielded only the negative phenotype from eggs. These results indicate that the environment within the hen applies stringent selection pressure on subpopulations of S. enterica serovar Enteritidis at certain points in the infection pathway that ends in egg contamination. The avian cecum, rather than the intestines, is the early interface between the environment and the host that supports emergence of subpopulation diversity. These results suggest that diet and other factors that alter cecal physiology should be investigated as a means to reduce egg contamination.
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Affiliation(s)
- Jean Guard-Bouldin
- Southeast Poultry Research Laboratory, Agricultural Research Service, U S Department of Agriculture, Athens, Georgia 30605, USA.
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Leuschner RGK, Beresford-Jones N, Robinson C. Difference and consensus of whole cell Salmonella enterica subsp. enterica serovars matrix-assisted laser desorption/ionization time-of-flight mass spectrometry spectra. Lett Appl Microbiol 2004; 38:24-31. [PMID: 14687211 DOI: 10.1046/j.1472-765x.2003.01436.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIM Application of MALDI-TOF MS for characterization of strains of Salmonella enterica subsp. enterica. METHODS AND RESULTS Whole cells were analysed by MALDI-TOF MS. Spectra with a maximum of 500 mass peaks between (m/z) 0 and 25000 were examined for consensus peaks manually and by a computer software algorithm. Consensus peaks were observed by both methods for spectra of Salmonella enterica serovars Derby, Hadar, Virchow, Anatum, Typhimurium and Enteritidis. CONCLUSIONS Differences in numbers of consensus peaks in spectra obtained by manual and computer comparison indicated that development of the software involving statistical analysis of peak accuracy is necessary. SIGNIFICANCE AND IMPACT OF THE STUDY Development of an analysis system for peak profiles in whole cell MALDI-TOF MS spectra to enable intra and interlaboratory comparison.
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Affiliation(s)
- R G K Leuschner
- Department for Environment, Food and Rural Affairs, Central Science Laboratory, Sand Hutton, York, UK.
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Liebana E, Garcia-Migura L, Clouting C, Cassar CA, Clifton-Hadley FA, Lindsay EA, Threlfall EJ, Chappell SA, Davies RH. Investigation of the genetic diversity among isolates of Salmonella enterica serovar Dublin from animals and humans from England, Wales and Ireland. J Appl Microbiol 2003; 93:732-44. [PMID: 12392517 DOI: 10.1046/j.1365-2672.2002.01737.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To assess the degree of genetic diversity among animal Salmonella Dublin UK isolates, and to compare it with the genetic diversity found among human isolates from the same time period. METHODS AND RESULTS One hundred isolates (50 human and 50 animal) were typed using plasmid profiling, XbaI-pulsed field gel electrophoresis (PFGE) and PstI-SphI ribotyping. Antimicrobial resistance data to 16 antibiotics was presented, and the presence of class-I integrons was investigated by real-time PCR. Seven different plasmid profiles, 19 ribotypes and 21 PFGE types were detected. A combination of the three methods allowed clear differentiation of 43 clones or strains. Eighteen isolates were resistant to at least one antimicrobial; five of them were multi-resistant and of these, only three presented class I integrons. CONCLUSIONS Ribotyping data suggest the existence of at least three very different clonal lines; the same distribution in well-defined groups was not evident from the PFGE data. The existence of a variety of clones in both animals and humans has been demonstrated. A few prevalent clones seem to be widely disseminated among different animal species and show a diverse geographical and temporal distribution. The same clones were found in animals and humans, which may infer that both farm and pet animals may act as potential vehicles of infection for humans. Some other clones seem to be less widely distributed. Clustering analysis of genomic fingerprints of Salmonella Dublin and Salm. Enteritidis isolates confirms the existence of a close phylogenetic relationship between both serotypes. SIGNIFICANCE AND IMPACT OF THE STUDY This paper describes the utility of a multiple genetic typing approach for Salm. Dublin. It gives useful information on clonal diversity among human and animal isolates.
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Affiliation(s)
- E Liebana
- Department of Bacterial Diseases, Veterinary Laboratories Agency-Weybridge, Addlestone, UK.
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Liebana E. Molecular tools for epidemiological investigations of S. enterica subspecies enterica infections. Res Vet Sci 2002; 72:169-75. [PMID: 12076110 DOI: 10.1053/rvsc.2001.0550] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Salmonella infection is one of the most prevalent reported food-borne diseases in industrialised countries, most often associated with eating contaminated eggs, poultry and pork. Traditionally, epidemiological investigations for Salmonella enterica have been based on phenotypic characteristics. However, the predominance of certain phenotypes within hosts or locations makes further epidemiological subgrouping necessary. The combination of conventional and molecular epidemiology data is yielding important insights into the understanding of the epidemiology of many infectious diseases, although at present there is no consensus on which molecular method is best suited for intraserotype differentiation within S. enterica. This paper reviews the current methodology for some of the most prevalent animal and human-associated serotypes.
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Affiliation(s)
- E Liebana
- Department of Bacterial Diseases, Veterinary Laboratories Agency-Weybridge, Addlestone, Surrey, KT15 3NB, UK.
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