Multilocus variable number tandem repeat analysis for Salmonella enterica subspecies

Abstract

Genomic analysis of Salmonella enterica revealed the existence of a variable number of tandem repeats (VNTR) at multiple loci. Some S. enterica strains are considered as references (Typhi Ty2, Typhi CT18, Typhimurium LT2, Enteritidis LK5, PT4, and Enteritidis 07-2642, and Newport). These allowed the selection of markers to develop the genotyping technique, multiple-locus VNTR analysis (MLVA). These markers were used to discriminate S. enterica isolated from humans, food, or the environment. In this report, the characteristics and specifications of 58 salmonella markers described from 2003 to 2009 are analyzed. Some VNTR loci were used as markers. The markers were used to discriminate S. enterica isolates from different sources and geographical localizations. Among the VNTR loci described in the published reports, eight presented with a high diversity index (DI) of polymorphism of more than 0.80. The selection of several markers within a single locus validated their polymorphism characteristic. Despite unequal DI values, the use of a panel of markers is a powerful discriminatory tool for the surveillance and identification of the source of salmonella outbreak. Depending on the markers selected, MLVA should be used either for macro- or microepidemiological purposes. The main challenge in the future for this technique is standardization.

Molecular Characterization ofSalmonellaEnteritidis: Comparison of an Optimized Multi-Locus Variable-Number of Tandem Repeat Analysis (MLVA) and Pulsed-Field Gel Electrophoresis

“…More recently, multilocus variable number of tandem repeat analysis (MLVA) involving amplification and fragment size analysis of the number of repeats in the variable number tandem repeat (VNTR) regions has been documented (Van Belkum, 2007). Good reproducibility, good discriminatory power, and the ease of performance and interpretation make MLVA a valuable technique (Kruy et al, 2011).…”

Salmonella Detection Methods for Food and Food Ingredients

“…However, serotyping is normally undertaken at reference laboratories and is rarely performed in routine food or clinical laboratories. Reference laboratories are also able to further type isolates using techniques such a phage typing (Anderson and Williams 1956;Callow 1959;Anderson 1964;Anderson et al 1977), antibiotic susceptibility (Bauer et al 1966), pulsed-field gel electrophoresis (PFGE), or other emerging genetic typing technologies such Multiple-Locus Variable Number Tandem Repeat Analysis (MLVA) and Multilocus sequence typing (MLST) (Kruy et al 2011). Although standard culture methods are excessively time-consuming, there is potential for further improvements, and thus many attempts have been made to maximize their efficiency by introducing new technologies, making reliability of detection more convenient, user friendly, as well as by reducing the costs of materials and labour (de Boer and Beumer 1999;Weenk, 1992).…”

Multiple-locus variable number of tandem repeats analysis of Salmonella enterica serotype paratyphi A from Yuxi and comparison with isolates from the Chinese Medical Culture Collection Center

“…Multi-locus variable number tandem repeat (VNTR) analysis (MLVA), a genotyping method based on polymerase chain reaction (PCR) and sequencing, which distinguishes tandem sequence repeats that vary in copy numbers (10,11), may be practical for subtyping SPA due to the simple operation, low cost, high-speed and weak laboratory-dependence (12). Furthermore, MLVA genotyping is becoming an important DNA-based typing tool for investigating strains that are related or unrelated to outbreaks (13). …”