Detection of virulence genes and plasmid replicons in Salmonella enterica subsp. enterica, which were allocated during 2014–2017 on the territory of Ukraine

Abstract

The article presents the results of the identification of virulence and antibiotic resistance genes, as well as plasmid replicons in isolates of Salmonella enterica subsp. enterica, which were isolated on the territory of Ukraine during 2014–2017. Also, plasmid replicons were identified for further determination of the type of plasmids contained in the genome of the isolates. The ability of Salmonella to obtain new properties is well known. The most common way is gaining of genetic information as a result of conjugation. In this case, genes encoding factors of pathogenicity, adhesion, virulence, or antibiotic resistance are localized on mobile genetic elements: replicons, transposons, or plasmids. The purpose of the work was to investigate isolates for the presence of genes of virulence, antibiotic resistance and replicons of plasmids in 50 isolates of Salmonella enterica subsp. enterica, isolated during 2014–2017 in Ukraine. The research was carried out by polymerase chain reaction with primers for 10 target genes/loci (invA, agfB, sefA, prt, sul1, 5'-3'CS, tetG, pN, pFIA, pFIIA) followed by visualization in agarose gel electrophoresis. It was found that 100% of all strains (50/50) had invA and agfB genes. SefA and prt genes were identified in 44% (22/50) and 58% (29/50) isolates, respectively. The sulfonamide resistance gene sul1 was detected in only four isolates, including 2 S. enteritidis isolates from Odesa and Kyiv oblasts, one isolate S. Virchow, and one unidentified isolate. The resistance gene for tetG tetracyclines was found only in 34% of isolates (17/50). The conservative sequence of integron In104 was detected in 52% of isolates (26/50). Replicon plasmid pN was detected in 68% of isolates (34/50), pFIIA – in 44% (22/50). Replicon pFIA is found in 8% (4/50) isolates. Solving the problem of non-typhoid salmonellosis is possible by controlling the epidemiological and epizootiological situation. According to WHO, more than 90 million cases of non-typhoid infection are reported annually. The cause of disease were mostly Enteritidis and Typhimurium. The variety and widespread distribution of salmonella is due primarily to their ability to adapt to the organism that they infect. The results obtained are important for determining the pathogenicity of isolates circulating in a particular area, as well as expanding the possibilities for tracking the source of infection.