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目的分析杭州市肺炎链球菌临床菌株parC/parE和gyrA/gyrB喹诺酮耐药决定区(QRDR)突变,及与喹诺酮类药物敏感性下降的相关性。方法采用琼脂稀释法检测37株临床菌株对8种抗生素的最小抑菌浓度(MIC),PCR法扩增目的基因并测序。结果对左氧氟沙星、莫西沙星和万古霉素全部敏感,其余抗生素耐药率都>60%,对左氧氟沙星MIC≤1 mg/L和MIC=2 mg/L分别有21株和16株。所有菌株gyrA/gyrB的均无突变,其中3株parC/parE也未见突变;34株临床菌株parE有突变,其中10株同时存在parC基因突变,parE基因分别有33株和8株发生I460V和D435N突变,parC基因有8株发生S79F突变。MIC=2 mg/L的菌株中parC/parE基因同时突变、S79F和/或D435N突变明显高于MIC≤1 mg/L菌株(χ2=4.2~6.2,P<0.05)。结论本地区未发现左氧氟沙星耐药肺炎链球菌株,parC/parE同时突变、S79F和/或D435N突变使左氧氟沙星MIC提高。监测临床菌株parC/parE和gyrA/gyrB突变情况,防止药物诱导耐药株的产生。
Objective To analyze the mutations of parco-parE and gyrA / gyrB quinolone-resistant-determining region (QRDR) in patients with Streptococcus pneumoniae in Hangzhou and their relationship with the decline of quinolone-sensitive drugs. Methods The minimum inhibitory concentration (MIC) of 37 strains of antibiotics against eight antibiotics was detected by agar dilution method. The target gene was amplified by PCR and sequenced. The results were sensitive to levofloxacin, moxifloxacin and vancomycin. The remaining antibiotic resistance rates were all over 60%. There were 21 and 16 strains of levofloxacin with MIC≤1 mg / L and MIC = 2 mg / L, respectively. All strains gyrA / gyrB no mutation, of which 3 parC / parE no mutation; 34 strains of clinical strains parE mutations, of which 10 were simultaneously parC gene mutations, parE gene were 8 and 8 I460V and D435N mutation, parC gene 8 S79F mutation occurred. The parC / parE gene was mutated simultaneously in MIC = 2 mg / L. The mutation of S79F and / or D435N was significantly higher than that of MIC ≤ 1 mg / L (χ2 = 4.2 ~ 6.2, P <0.05). Conclusion No levofloxacin-resistant Streptococcus pneumoniae strains were found in the region, and parC / parE mutations were simultaneously found. The S79F and / or D435N mutations increased levofloxacin MIC. To monitor the mutations of parC / parE and gyrA / gyrB in clinical isolates to prevent drug-induced drug-resistant strains.