title: Detection of the Smqnr quinolone protection gene and its prevalence in clinical isolates of Stenotrophomonas maltophilia in China.
abstract: The aim of this study was to detect novel variants of the Stenotrophomonas maltophilia Smqnr gene family and analyse the prevalence of Smqnr genes in clinical isolates of S. maltophilia in China. In total, 442 clinical isolates of S. maltophilia were collected from nine hospitals in four provinces in China. Antimicrobial susceptibility testing against six commonly used antibiotics was performed on these isolates. The sequences of the Smqnr genes amplified by PCR were aligned with those of known Smqnr genes in GenBank and an Smqnr database. The resistance rate against co-trimoxazole was highest at 48.6 %, followed by resistance rates against ceftazidime, chloramphenicol, ticarcillin/clavulanate and tigecycline at 28.7, 21.3, 19.0 and 16.1 %, respectively. The highest susceptibility was shown to levofloxacin, with a resistance rate of just 6.1 %. Smqnr genes were detected in 114 isolates, and comprised 11 previously identified genes and 20 new variants, bringing the total number of known Smqnr genes to 47. The 20 novel Smqnr genes were designated Smqnr28-47 and the encoded proteins showed only 1-12 amino acid differences among each other. The most common Smqnr genes in China were Smqnr8 and its variant Smqnr35 with prevalences of 17.5 % (20/114) and 13.2 % (15/114), respectively. Both the known and the novel Smqnr genes were discovered in both quinolone non-sensitive and sensitive isolates with similar frequency, suggesting that the Smqnr gene makes little contribution to quinolone resistance in this organism.
authors.affiliation: Second Affiliated Hospital of Zhejiang University, 88 JieFang Road, Hangzhou 310009, PR China.
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Second Affiliated Hospital of Zhejiang University, 88 JieFang Road, Hangzhou 310009, PR China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Sun
authors.affiliation: Beijing Hospital, Beijing 100730, PR China.
authors.forename: Yun-Jian
authors.initials: YJ
authors.lastname: Hu
authors.affiliation: People's Hospital of Sichuan, Chengdu 610072, PR China.
authors.forename: Hua
authors.initials: H
authors.lastname: Yu
authors.affiliation: People's Hospital of Henan, Zhengzhou 450003, PR China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.affiliation: First People's Hospital of Hangzhou, Hangzhou 310009, PR China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Shen
authors.affiliation: Central Hospital of Lishui, Lishui 323000, PR China.
authors.forename: Guo-Xiong
authors.initials: GX
authors.lastname: Li
authors.affiliation: Zhejiang Hospital of Traditional Chinese Medicine, Hangzhou 310009, PR China.
authors.forename: Jun-Min
authors.initials: JM
authors.lastname: Cao
authors.affiliation: Hangzhou Hospital of Traditional Chinese Medicine, Hangzhou 310009, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.affiliation: People's Hospital of Zhuji, Zhuji 311800, PR China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Second Affiliated Hospital of Zhejiang University, 88 JieFang Road, Hangzhou 310009, PR China.
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Zhou
authors.affiliation: Second Affiliated Hospital of Zhejiang University, 88 JieFang Road, Hangzhou 310009, PR China.
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Hu
authors.affiliation: Second Affiliated Hospital of Zhejiang University, 88 JieFang Road, Hangzhou 310009, PR China.
authors.forename: Gong-Xiang
authors.initials: GX
authors.lastname: Chen
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002681:China / Q000453:epidemiology; D024881:Drug Resistance, Bacterial; D015964:Gene Expression Regulation, Bacterial; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology*; D006801:Humans; D020128:Inhibitory Concentration 50; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010802:Phylogeny; D015363:Quinolones / Q000494:pharmacology*; D020615:Stenotrophomonas maltophilia / Q000235:genetics* / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015363:Quinolones