H (2010) qnrVC-like gene located in a novel complex class 1 integron harboring the ISCR1 element in an Aeromonas punctata strain from an aquatic environment in Shandong Province, China. Antimicrob Agents Chemother 54

A qnrVC-like gene, qnrVC4, was found in a novel complex class 1 integron gene cassette array following the ISCR1 element and blaPER-1 in a multidrug-resistant strain of the aquatic bacterium Aeromonas punctata. The deduced QnrVC4 protein sequence shares 45 % to 81 % amino acid identity with quinolone resistance determinants QnrB6, QnrA1, QnrS1, QnrC, QnrVC1, and QnrVC3. A Ser-83 to Ile amino acid substitution in gyrase A may be mainly responsible for ciprofloxacin resistance in this strain. Aeromonas spp. have various class 1 integrons and have been proposed as clinical and environmental reservoirs of antibiotic determinants (2, 9). Resistance to quinolones de-pends on mutations in the gyrase and/or topoisomerase IV genes (6, 15), and plasmid-mediated resistance determi-nants (qnrS2) have been found in Aeromonas spp. (2, 12, 18). Since qnr was first detected (11), 6 qnrA variants, 20 qnrB variants, and 4 qnrS variants have been described (7). Two homologs, qnrVC1 and qnrVC2, have been found in inte-grons (5). Recently, qnrC and qnrD were isolated in Chin