Antimicrob Agents Chemother 2020 08 20;64(9). Epub 2020 Aug 20.
Key Laboratory of Medical Genetics of Zhejiang Province, Key Laboratory of Laboratory Medicine, Ministry of Education, China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
Members of the complex are important opportunistic human pathogens capable of causing a wide variety of infections. During recent decades, aminoglycoside-resistant complex isolates have increasingly been reported and have become a major concern. Here, we employed high-throughput sequencing in combination with specific PCR assays to investigate the prevalence of aminoglycoside resistance genes among 170 isolates of the complex collected from a teaching hospital in Wenzhou, China. A total of 12 known genes [, , , , , , , , , , , and ] and 1 novel gene [] were identified, with (71.18%), (55.29%), and (52.35%) being the most prevalent, and was detected with a positive rate of 21.76% (37/170). The gene was 810 bp in length and encoded a protein that shared 72 to 78% identities with previously known AAC(3)-II aminoglycoside 3--acetyltransferases. The MICs of gentamicin and tobramycin were 512 μg/ml and 64 μg/ml, respectively, when was cloned into DH5α. All -positive isolates exerted broad aminoglycoside resistance profiles, mediated by the coexistence of multiple resistance genes. Moreover, aminoglycoside resistance and resistance genes were found to be transferable in most strains (24/37). Nevertheless, pulsed-field gel electrophoresis (PFGE) and dendrogram analysis showed clonal diversity among these isolates. S1 nuclease PFGE, Southern hybridization, and whole-genome sequencing indicated that was located on transferable as well as nontransferable plasmids of various sizes. The analysis of the genetic environment suggested that is embedded within a class 1 integron, with IS playing an important role in its mobility.