Comparison of drug sensitivity and genotypes of clinically isolated strains of levofloxacin-resistant Streptococcus pneumoniae obtained from Okinawa Island, the Japanese main island and Hong Kong
Comparison of drug sensitivity and genotypes of clinically isolated strains of levofloxacin-resistant Streptococcus pneumoniae obtained from Okinawa Island, the Japanese main island and Hong Kong
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DOI：
10.1038/ja.2011.46
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发表时间：
2011-08
期刊：
影响因子：
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通讯作者：
S. Sunagawa;J. Fujita;F. Higa;M. Tateyama;Shusaku Haranaga;I. Nakasone;N. Yamane;Tsukasa Uno
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文献类型：
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作者：
S. Sunagawa;J. Fujita;F. Higa;M. Tateyama;Shusaku Haranaga;I. Nakasone;N. Yamane;Tsukasa Uno
耐氟喹诺酮肺炎链球菌在世界范围内的流行率正在上升。本研究比较了从香港、冲绳岛和日本本州分离的肺炎链球菌对左氧氟沙星(LVFX)的敏感性和基因分型。采用微量肉汤稀释法测定氟喹诺酮类药物(左旋氧氟沙星、托氟沙星、环丙沙星、加替沙星、西他沙星)及其他抗生素(青霉素G、头孢卡彭、头孢妥仑、克拉霉素、阿奇霉素)的MIC值。对这些菌株的gyrA、gyrB、parC和pARE基因进行测序，分析其对喹诺酮类药物的耐药决定区。所有测试的40个菌株在gyrA、gyrB、parc或parE的QRDR上都有一个以上的氨基酸替换。虽然从香港获得的菌株似乎有一些克隆性，但从冲绳和日本获得的菌株没有克隆性。从香港、冲绳岛和日本主岛获得的菌株经脉冲场凝胶电泳法分析表明，它们的遗传差异很大。对L−1耐药株的MIC值范围为0.12~0.5 mg L−1，对耐药株的MIC80值为0.2 5 mg L−1。本研究提示，肺炎链球菌对3个耐药部位的MIC值均相似，且对旋转酶A和拓扑异构酶IV的qrdrs存在多重突变。
The prevalence of fluoroquinolone-resistant Streptococcus pneumoniae is increasing worldwide. In the present study, a comparison of drug sensitivity and genotypes of clinically isolated strains of levofloxacin (LVFX)-resistant S. pneumoniae obtained from Hong Kong, Okinawa Island and the Japanese main island (Honshu) was performed. MICs of quinolones (LVFX, tosufloxacin, ciprofloxacin, gatifloxacin and sitafloxacin (STFX)) and other antibiotics (penicillin G, cefcapene, cefditoren, clarithromycin and azithromycin) were determined by a microdilution broth method according to the Clinical and Laboratory Standards Institute Standards. The quinolone-resistance determining regions (QRDRs) of gyrA, gyrB, parC and parE of these strains were analyzed by PCR-based sequencing. All 40 strains tested had more than one amino-acid substitution in the QRDRs of gyrA, gyrB, parC or parE. Although there seemed to be some clonality in strains obtained from Hong Kong, there was no clonality in strains obtained from Okinawa and Japan. Strains obtained from Hong Kong, Okinawa Island and the Japanese main island were genetically different by pulsed-field gel electrophoresis analysis. The range of MIC values of STFX against isolates resistant to LVFX (MIC 4–32 mg l− 1) was 0.12–0.5 mg l− 1, and MIC 80 values of STFX against LVFX-resistant isolates were 0.25 mg l− 1. This study suggests that LVFX-resistant S. pneumoniae is similar in all three locations and STFX is potent against LVFX-resistant S. pneumoniae with multiple mutations in QRDRs of gyrase A and topoisomerase IV.