Index cluster analysis of drug resistance-related genes in multidrug-resistant shigella flexneri

Abstract

Objective To investigate the antimicrobial characteristics of shigella flexneri and to analyze the correlation between acquired resistance genes and mobile genetic elements. Methods 139 strains of shigella flexneri collected from each district of Centers for Disease Control and Prevention in Shanghai from 2010 to 2014 were recovered. The K-B method was used to determine the susceptibility of the strains to 13 antibiotics. And then 17 kinds of acquired resistance genes to β-lactams, sulfonamides, aminoglycosides and 7 kinds of genetic markers of mobile genetic elements were analyzed by PCR. Index cluster analysis was performed to explore the correlation between them. Results Among 139 strains of Shigella flexneri, 3 kinds of genetic markers of mobile genetic elements, ISEcp1, intI1 and trbC, 3 kinds of acquired β-lactam-resistance genes, CTX-M, OXA and TEM, 2 kinds of acquired aminoglycoside-resistance genes, ant(3)-I and aac(6′)-Ib, 1 kind of overlapping gene of quaternary ammonium disinfectant and sulfonamides, qacEΔ1-sull and 1 kind of sulfamethoxazole/trimethoprim-resistant gene, dfrA1 were detected. The resistence genes, OXA, ant(3)-I and drfA1 were highly related with each other, which were mediated by Class 1 integron. TEM, qacEΔl-sull and aac(6′)-Ib were highly related with each other, which were mediated by trbC. Conclusion Acquired multidrug resistance gene transfer mediated by a variety of mobile genetic elements may have largely contributed to the spreading of resistant strains of Shigella.(Chin J Lab Med, 2017, 40: 970-974) Key words: Shigella; Mobile genetic element; Index cluster analysis