AUTHOR=Wang Dongguo , Huang Xitian , Chen Jiayu , Mou Yonghua , Li Haijun , Yang Liqin 

TITLE=Characterization of genetic structures of the QepA3 gene in clinical isolates of Enterobacteriaceae

JOURNAL=Frontiers in Microbiology

VOLUME=6

YEAR=2015

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2015.01147

DOI=10.3389/fmicb.2015.01147

ISSN=1664-302X

ABSTRACT=<p><italic>QepA</italic> is one of the genes that confer quinolone resistance in bacteria. The aim of this study was to analyze the genetic structures of plasmids that carry a <italic>qepA3</italic>, a recently discovered allele of <italic>qepA</italic> in <italic>Enterobacteriaceae</italic> clinical isolates. 656 non-redundant <italic>Enterobacteriaceae</italic> clinical isolates were screened for the <italic>qepA3</italic> gene and five isolates were identified to carry the gene. Plasmids were isolated from these isolates and were found to increase antibiotic resistance once the plasmids were transferred to <italic>Escherichia coli</italic>. These plasmids were subcloned and sequenced to analyze the genetic structures surrounding the <italic>qepA3</italic> gene. The results showed that the five plasmids had different genetic structures; two of the <italic>qepA3</italic>-containning isolates had either the <italic>bla</italic><sub>CTX-M-14</sub> or <italic>bla</italic><sub>TEM-12</sub> gene instead of the <italic>bla</italic><sub>TEM-1</sub> gene. The structures of both pKP3764 and pECL3786 have not been previously described. In comparison with pHPA, there were a number of changes in DNA sequences up- and down-stream of the <italic>qepA3</italic> gene. These findings provide better understanding of the genetic variations in <italic>qepA3</italic> and would be useful for diagnosis and control of quinolone resistance in clinical settings.</p>