Quinolone Resistance Genes and Their Contribution to Resistance in Vibrio cholerae Serogroup O139

Abstract

Background. Quinolones are commonly used for reducing the duration of diarrhea, infection severity, and limiting further transmission of disease related to Vibrio cholerae, but V. cholerae susceptibility to quinolone decreases over time. In addition to mutations in the quinolone-resistance determining regions (QRDRs), the presence of qnr and other acquired genes also contributes to quinolone resistance. Results. We determined the prevalence of quinolone resistance related genes among V. cholerae O139 strains isolated in China. We determined that eight strains carried qnrVC, which encodes a pentapeptide repeat protein of the Qnr subfamily, the members of which protect topoisomerases from quinolone action. Four qnrVC alleles were detected: qnrVC1, qnrVC5, qnrVC12, and qnrVC9. However, the strains carrying qnrVC1, qnrVC5, and qnrVC12 were ciprofloxacin (CIP)-sensitive. Contrastingly, the strain carrying qnrVC9 demonstrated high CIP resistance. qnrVC9 was carried by a small plasmid, which was conjugative and contributed to the high CIP resistance to the receptor V. cholerae strain. The same plasmid was also detected in V. vulnificus. The qnrVC1, qnrVC5, and qnrVC12 were cloned into expression plasmids and conferred CIP resistance on the host V. cholerae O139 strain. Conclusions. Our results revealed the contribution of quinolone resistance mediated by the qnrVC9 carried on the small plasmid and its active horizontal transfer among Vibrio species. The results also suggested the different effects of qnrVC alleles in different V. cholerae strains, which is possibly due to differences in sequences of qnrVC alleles and even the genetic characteristics of the host strains.

Genetic approach toward linkage of Iran 2012–2016 cholera outbreaks with 7th pandemic Vibrio cholerae

“…This gene has also been found in quinolone-susceptible strains of ST75 (SLV of ST579) in South Africa [ 38 ]. This gene, different alleles of which are located in a chromosomal super-integron, is not necessarily related to resistance as indicated here and in several previous studies [ 39 , 40 ].…”

Whole Genome Sequencing and Pan-Genomic Analysis of Multidrug-Resistant Vibrio cholerae VC01 Isolated from a Clinical Sample

“…Over time, V. cholerae resistance to major classes of antibiotics is concerning. An example is the incidence of quinolone resistance genes in V. cholerae O139 strains from China that were conjugative and contributed due to a CIP-resistant plasmid similar to that observed in V. vulnificus [ 84 ]. Additionally, mobile genetic elements, particularly plasmids, have significantly contributed to the spread of antimicrobial resistance.…”