Detection of the Smqnr quinolone protection gene and its prevalence in clinical isolates of Stenotrophomonas maltophilia in China
Detection of the Smqnr quinolone protection gene and its prevalence in clinical isolates of Stenotrophomonas maltophilia in China
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DOI：
10.1099/jmm.0.037309-0
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发表时间：
2012-04-01
影响因子：
3
通讯作者：
Chen, Gong-Xiang
中科院分区：
文献类型：
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作者：
Zhang, Rong;Sun, Qian;Chen, Gong-Xiang
本研究的目的是检测嗜麦芽寡养单胞菌 Smqnr 基因家族的新变异，并分析 Smqnr 基因在中国嗜麦芽窄食单胞菌临床分离株中的流行情况。总共从中国四个省的九家医院收集了 442 株嗜麦芽糖链球菌临床分离株。对这些分离株进行了针对六种常用抗生素的抗菌药物敏感性测试。通过PCR扩增的Smqnr基因的序列与GenBank和Smqnr数据库中已知的Smqnr基因的序列进行比对。其中对复方新诺明的耐药率最高，为48.6%，其次为头孢他啶、氯霉素、替卡西林/克拉维酸和替加环素，分别为28.7%、21.3%、19.0%和16.1%。对左氧氟沙星的敏感性最高，耐药率仅为6.1%。在 114 个分离株中检测到 Smqnr 基因，其中包括 11 个先前识别的基因和 20 个新变体，使已知的 Smqnr 基因总数达到 47 个。这 20 个新的 Smqnr 基因被命名为 Smqnr28-47，编码的蛋白质彼此之间仅显示 1-12 个氨基酸差异。中国最常见的Smqnr基因是Smqnr8及其变体Smqnr35，患病率分别为17.5%（20/114）和13.2%（15/114）。已知的和新的 Smqnr 基因在喹诺酮不敏感和敏感分离株中均以相似的频率被发现，表明 Smqnr 基因对该生物体的喹诺酮抗性贡献不大。
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.