Tandem Repeat Analysis for Surveillance of Human<i>Salmonella</i>Typhimurium Infections

Torpdahl, Mia; Sørensen, Gitte; Lindstedt, Bjørn-Arne; Nielsen, Eva Møller

doi:10.3201/eid1303.060460

Cited by 101 publications

(112 citation statements)

References 25 publications

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“…Isolates generated restriction fragments with molecular size ranging from 40 to 700 kb fragments, representing 11 distinct macro restriction profiles. Dendrogram showing similarities of Xba1 digested macro restriction profiles of NTS isolates generated by bio-rod finger printing with the band matching coefficient of Dice and the UPGMA clustering many laboratories [32][33][34]. Genotyping of Salmonella is a rapidly expanding field and many new methods have been developed in recent years.…”

Section: Discussionmentioning

confidence: 99%

Molecular Epidemiology of Nontyphoidal Salmonella in Poultry and Poultry Products in India: Implications for Human Health

et al. 2015

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Human infections with non-typhoidal Salmonella (NTS) serovars are increasingly becoming a threat to human health globally. While all motile Salmonellae have zoonotic potential, Salmonella Enteritidis and Salmonella Typhimurium are most commonly associated with human disease, for which poultry are a major source. Despite the increasing number of human NTS infections, the epidemiology of NTS in poultry in India has not been fully understood. Hence, as a first step, we carried out epidemiological analysis to establish the incidence of NTS in poultry to evaluate the risk to human health. A total of 1215 samples (including poultry meat, tissues, egg and environmental samples) were collected from 154 commercial layer farms from southern India and screened for NTS. Following identification by cultural and biochemical methods, Salmonella isolates were further characterized by multiplex PCR, allele-specific PCR, enterobacterial repetitive intergenic consensus (ERIC) PCR and pulse field gel electrophoresis (PFGE). In the present study, 21/1215 (1.73 %) samples tested positive for NTS. We found 12/392 (3.06 %) of tissue samples, 7/460 (1.52 %) of poultry products, and 2/363 (0.55 %) of environmental samples tested positive for NTS. All the Salmonella isolates were resistant to oxytetracycline, which is routinely used as poultry feed additive. The multiplex PCR results allowed 16/21 isolates to be classified as S. Typhimurium, and five isolates as S. Enteritidis. Of the five S. Enteritidis isolates, four were identified as group D Salmonella by allele-specific PCR. All of the isolates produced different banding patterns in ERIC PCR. Of the thirteen macro restriction profiles (MRPs) obtained by PFGE, MRP 6 was predominant which included 6 (21 %) isolates. In conclusion, the findings of the study revealed higher incidence of contamination of NTS Salmonella in poultry tissue and animal protein sources used for poultry. The results of the study warrants further investigation on different type of animal feed sources, food market chains, processing plants, live bird markets etc., to evaluate the risk factors, transmission and effective control measures of human Salmonella infection from poultry products.

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Section: Discussionmentioning

confidence: 99%

Molecular Epidemiology of Nontyphoidal Salmonella in Poultry and Poultry Products in India: Implications for Human Health

et al. 2015

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“…The allele difference at one locus was thought to be a mutation occurring during the epidemic period (Torpdahl et al, 2007). In the two outbreak investigations tested here, there were mixed bacterial populations in the infectious food sources with different genotypes at fnbB locus in the first investigation and at the sdrD locus in the second investigation (Table 4).…”

Section: Discussionmentioning

confidence: 97%

Selection of optimal combinations of loci by the Optimal Combination Finder computer program from a group of variable number tandem repeat loci for use in Staphylococcus aureus food poisoning case investigations

Wang

Huang

Blair

et al. 2012

Journal of Medical Microbiology

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Staphylococcus aureus is a pathogen that can be the cause of nosocomial infections, communityacquired diseases and food-borne disease outbreaks. A number of variable number tandem repeat loci have been reported by various groups for use in epidemiological studies and outbreak investigations. The aim of this study was to systematically evaluate a total of 18 commonly used loci with the same S. aureus population so that the properties of each locus could be compared and used for typing, and to develop a computer program enabling calculation of the Simpson index (SI) of all possible loci combinations so that an optimal combination of loci could be identified for multilocus variable-number tandem-repeat analysis (MLVA) typing. A collection of 160 S. aureus isolates from patients with sporadic food-borne illnesses, and pet animals, such as canine, feline and equine pets, with skin infections were used to assess the MLVA loci. The newly developed Optimal Combination Finder (OCF) computer program was used for the analysis and it was found that the minimal number of loci combinations that produced the same SI (0.999528) as that of the 18 loci combined was eight; SIRU05, SIRU07, SIRU13, SIRU15, SIRU21, fnbB, sdrD and clfB. This suggested that the optimal combination of eight loci could be used for the routine investigation and surveillance of future S. aureus outbreaks instead of using all 18 loci. In addition, the OCF software could be a useful tool for the development of typing schemes for other organisms.

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“…Typhimurium DT104 and 16 DT104b were obtained from persons with clinical disease in Denmark. Several outbreaks and clusters of DT104 were detected; some have previously been reported (5)(6)(7)(8). The 323 isolates were characterized by MLVA (97% of isolates), PFGE (78%), and susceptibility testing (100%).…”

Section: The Studymentioning

confidence: 89%

“…Susceptibility to a standard panel of antimicrobial agents (www.danmap.org) was determined by microbroth dilution and interpreted according to Clinical and Laboratory Standards Institute (CLSI) guidelines (9), except for ciprofl oxacin (>0.125 μg/mL was used as breakpoint). The 5-locus MLVA described by Lindstedt et al (10) and PFGE, according to the PulseNet protocol (11), were performed and analyzed as previously described (5). To obtain a cluster-independent data set, we reduced the 323 isolates to 146 unique strains on the basis of the MLVA and resistance profi le (i.e., with different MLVA and/or resistance profi le) ( Table 1).…”

Section: The Studymentioning

confidence: 99%

Variation in Antimicrobial Resistance in Sporadic and Outbreak-relatedSalmonella entericaSerovar Typhimurium

Nielsen¹,

Torpdahl²,

Ethelberg³

et al. 2009

Emerg. Infect. Dis.

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The prevalence of different antimicrobial resistance profiles and variants of the Salmonella genomic island 1 (SGI1) was reported for Salmonella enterica serovar Typhimurium DT104 strains isolated from patients in Denmark. Variation in antimicrobial resistance and corresponding changes of SGI1 were shown among isolates from a foodborne outbreak.

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Tandem Repeat Analysis for Surveillance of HumanSalmonellaTyphimurium Infections

Cited by 101 publications

References 25 publications

Molecular Epidemiology of Nontyphoidal Salmonella in Poultry and Poultry Products in India: Implications for Human Health

Molecular Epidemiology of Nontyphoidal Salmonella in Poultry and Poultry Products in India: Implications for Human Health

Selection of optimal combinations of loci by the Optimal Combination Finder computer program from a group of variable number tandem repeat loci for use in Staphylococcus aureus food poisoning case investigations

Variation in Antimicrobial Resistance in Sporadic and Outbreak-relatedSalmonella entericaSerovar Typhimurium

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