Use of multiple‐locus variable‐number of tandem repeats analysis (MLVA) to investigate genetic diversity of Salmonella enterica subsp. enterica serovar Typhimurium isolates from human, food, and veterinary sources. Issue 1 (23rd August 2017)

• Record Type: Journal Article
• Authors: Mateva, Gergana; Pedersen, Karl; Sørensen, Gitte; Asseva, Galina; Daskalov, Hristo; Petrov, Petar; Kantardjiev, Todor; Alexandar, Irina; Löfström, Charlotta
• Is Part Of: MicrobiologyOpen. Volume 7:Issue 1(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-08-23
• Subjects: antimicrobial resistance -- laboratory surveillance -- MLVA -- public health -- Salmonella genetic diversity -- zoonoses; Microbiology -- Periodicals; 579
• DOI: 10.1002/mbo3.528
• Languages: English
• ISSNs: 2045-8827

Abstract

Abstract: Salmonella enterica subspecies enterica serovar Typhimurium is the most common zoonotic pathogen in Bulgaria. To allow efficient outbreak investigations and surveillance in the food chain, accurate and discriminatory methods for typing are needed. This study evaluated the use of multiple‐locus variable‐number of tandem repeats analysis (MLVA) and compared results with antimicrobial resistance (AMR) determinations for 100 S . Typhimurium strains isolated in Bulgaria during 2008–2012 (50 veterinary/food and 50 human isolates). Results showed that isolates were divided into 80 and 34 groups using MLVA and AMR, respectively. Simpson's index of diversity was determined to 0.994 ± 0.003 and 0.945 ± 0.012. The most frequently encountered MLVA profiles were 3‐11‐9‐NA‐211 ( n = 5); 3‐12‐9‐NA‐211 ( n = 3); 3‐12‐11‐21‐311 ( n = 3); 3‐17‐10‐NA‐311 ( n = 3); 2‐20‐9‐7‐212 ( n = 3); and 2‐23‐NA‐NA‐111 ( n = 3). No clustering of isolates related to susceptibility/resistance to antimicrobials, source of isolation, or year of isolation was observed. Some MLVA types were found in both human and veterinary/food isolates, indicating a possible route of transmission. A majority (83%) of the isolates were found to be resistant against at least one antimicrobial and 44% against ≥4 antimicrobials. Further studies are needed to verify MLVA usefulness over a longer period of time and with more isolates, including outbreak strains. Abstract : This study presents the multiple‐locus variable‐number of tandem repeats analysis (MLVA) as promising tool in differentiation of Salmonella Typhimurium isolates for surveillance. Salmonella molecular typing is used for the first time for 100 Bulgarian isolates from human and veterinary origin. The profiles are compared with other isolates from different countries and could be used for future comparisons. Some MLVA types were found in both human and veterinary/food sources. Forty‐four percent of isolates studied were resistant to ≥4 antimicrobials. It is demonstrated how new molecular strategies could be used to aid classical diagnostic methods for quick comparison of pathogens.