Transmissive Antibiotic Resistance, Associated with the SXT Element, in Cholera Vibrios Isolated in the Territory of Russia

Abstract

Aim. Detection of SXT elements in cholera vibrios O1 and nonO1/nonO139 serogroups and study of the effectiveness of their conjugative transmission to Escherichia coli cells.Materials and methods. In conjugation experiments, Vibrio cholerae O1 El Tor (3) and V. cholerae nonO1/ nonO139 (3) strains were used as donors. Donor strains, recipients, and transconjugants were tested in realtime PCR for sensitivity to antibiotics and for the presence of drug resistance genes and integrase gene (int). Electrophoresis was carried out on a 0.7% agarose gel with ethidium bromide staining.Results. Resistance to chloramphenicol, trimethoprim/sulfamethoxazole, streptomycin was transmitted in conjugation experiments with a frequency of 2.1 × 10–9–7.1 × 10–9. The genes int and dfrA1 (resistance to trimethoprim/sulfamethoxazole) were found in most V. cholerae strains, and were stably transmitted to E. coli QD Rif r cells and in reverse crosses of V. cholerae O1 El Tor 5879 Nalr .Conclusion. The detection of the SXT element in V. cholerae strains and its successful horizontal transfer emphasize the need to detect such mobile genetic elements to control the spread of antibiotic resistance in V. cholerae.