2013年中国桶装水铜绿假单胞菌的复核验证及耐药特征分析

Verification and analysis of antimicrobial resistance on Pseudomonas aeruginosa isolated from bottled water in China,2013

目的了解2013年中国21个省市自治区桶装水来源铜绿假单胞菌的鉴定正确率,对我国桶装水来源铜绿假单胞菌的耐药状况进行初步分析。方法采用基于eta2和opr I两对基因的PCR方法对桶装水来源铜绿假单胞菌进行快速复核,使用Vitek GN生化鉴定卡进行生化验证,评价分离菌株的复核正确率和PCR方法的准确度,采用微量肉汤稀释法,对8类12种抗生素的耐药性进行测定。结果两对引物均能对铜绿假单胞菌扩增出预期的目的条带,但eta2具有更高的特异性;抽样进行生化试验结果显示2013年各地上报并运送的菌株复核正确率为100%;两种基因的PCR方法准确度均在95%以上,但均存在较低比例假阴性;2013年中国21个省市自治区上报的531株铜绿假单胞菌耐药率为11.68%(62/531),主要耐受多粘菌素B(5.27%,28/531)、氨曲南(4.14%,22/531)和美罗培南(3.01%,16/531),替卡西林/克拉维酸和替卡西林的中介率分别为43.31%(230/531)和25.42%(135/531)。结论各地上报分离的铜绿假单胞菌的准确性较高,PCR方法可对桶装水来源铜绿假单胞菌进行快速筛选,结合生化鉴定方法可准确鉴定。桶装水来源铜绿假单胞菌的耐药处于较低水平,但替卡西林/克拉维酸和替卡西林某种程度上显示了一定的耐药趋势,需要定期监测,以阐明桶装水中的铜绿假单胞菌的耐药特征和耐药趋势。

Objective The aim of this study was to evaluate the identification accuracy and to acquire a preliminary analysis for antimicrobial resistance of Pseudomonas aeruginosa isolated from bottled water in 21 provinces of China in2013.Methods PCR method based on eta2 and opr I genes was used in the rapid verification for Pseudomonas aeruginosa isolates,and biochemical method with Vitek GN cards was used as reference method.Broth microdilution method was used to obtain minimal inhibitory concentrations（MICs）of all 531 strains to 12 antibiotics belonging to 8 categories.Results eta2 and opr I genes were validated by target bands and eta2 was more specific.The results of biochemical test showed that the identification accuracy of all provinces was 100%.PCR method using two genes could achieve an accuracy over 95%with few false negative results.Among 531 Pseudomonas aeruginosa strains from 21 provinces in China,there were62（11.68%）drug resistanta isolates in all,and these strains showed the highest resistance to polymyxin B（5.27%）,followed by aztreonam（4.14%）and meropenem（3.01%）.230（43.31%）and 135（25.42%）of the strains tested were intermediate to ticarcillin-clavulanate and ticarcillin respectively.Conclusion The accuracy of Pseudomonas aeruginosa identification in all provinces was qualified,and PCR test could be a rapid and accurate screening method for detecting Pseudomonas aeruginosa in combination with traditional biochemical methods.Compared with clinical isolates,Pseudomonas aeruginosa isolated from bottled water remained at low drug resistance level,but there was a potentialtendency that strains may become more resistant to ticarcillin-clavulanate and ticarcillin to some degree,so regular monitoring was necessary to recognize antimicrobial resistance characteristics and tendency of Pseudomonas aeruginosa isolated from bottled water.