我国非伤寒沙门菌对多粘菌素的耐药现况及mcr-1基因携带概况  

Polymyxin resistance and mcr-1 prevalence in non-typhoid Salmonella isolates in China

作　　者：曹阳[1] 遇晓杰[2] 韩营营 李杰[1] 阚飙[1] 闫梅英[1] 

机构地区：[1]中国疾病预防控制中心传染病预防控制所,北京102206 [2]黑龙江省疾病预防控制中心,黑龙江哈尔滨150000

出　　处：《疾病监测》2017年第5期365-371,共7页Disease Surveillance

基　　金：国家重点基础研究发展计划(973计划)(No.2013CB127204)~~

摘　　要：目的初步探究我国非伤寒沙门菌对多粘菌素的耐药情况。方法利用微量肉汤稀释法,测定不同来源404株非伤寒沙门菌对多粘菌素B及多粘菌素E的最小抑菌浓度(MIC),计算耐药率,推测野生沙门菌株的耐药阈值。同时利用聚合酶链式反应(PCR)方法检测菌株携带mcr-1基因的情况。结果 404株沙门菌对多粘菌素B及E的MIC范围为≤0.125μg/ml至>16μg/ml,对多粘菌素B的MIC50、MIC90分别为1μg/ml和8μg/ml;对多粘菌素E的MIC50、MIC90分别为2μg/ml和8μg/ml。优势血清型鼠伤寒沙门菌、肠炎沙门菌及德尔卑沙门菌对多粘菌素B及E的MIC值分布不同。以8μg/ml为耐药阈值判定折点,实验菌株对多粘菌素B及E的耐药率分别为10.89%和15.84%;其中食源性沙门菌、人源性沙门菌及动物源性沙门菌对多粘菌素B的耐药率分别为12.50%、17.16%和0.00%(P<0.01);对多粘菌素E的耐药率分别为8.30%、27.94%和0.78%(P<0.01)。发现7株同时耐多粘菌素及三代头孢的菌株。发现1株人源鼠伤寒沙门菌携带可转移的mcr-1基因,且该菌株产ESBLs。结论发现我国人源产ESBLs的沙门菌携带mcr-1基因。根据体外药敏结果,非伤寒沙门菌对多粘菌素B及E的耐药折点设为8μg/ml较宜。沙门菌对多粘菌素的耐药率尚处于低水平,应加强不同来源沙门菌对多粘菌素的耐药监测。Objective To investigate the prevalence of polymyxin （polymyxin B and polymyxin E） resistance in non- typhoid Salmonella strains in China. Methods Phenotypic antimicrobial susceptibility test was conducted by means of broth dilution to detect the prevalence of polymyxin resistance in 404 strains of non-typhoid Salmonella from different sources in China. The resistant breakpoints for polymyxin B and polymyxin E were set based on minimal inhibitory concentration （MIC） distribution data. The carriage of mcr-1 gene in polymyxin resistant Salmonella strains was detected with PCR. Results The polymyxin MICs ranged from ≤0. 125 txg/ml to 〉 16 μg/ml. The MIC50 and MIC90 of polymyxin B were 1 μg/ml and 8 μg/ml, respectively. While the MIC50 and MIC90 of polymyxin E were 2 μg/ml and 8 μg/ml, respectively. The distributions of MICs for different predominant serotypes, including Salmonella Typhimurium, Salmonella Enteritidis and Salmonella Derby, were different. The resistant breakpoint MICs for polymyxin B and polymyxin E were set at 8 μg/ml based on their MIC frequency distribution. According to this criteria, the overall resistance rates to polymyxin B and polymyxin E were 10.89% and 15.84%, respectively. The resistance rates of Salmonella with different sources to polymyxin B differed significantly （food source 12. 50% , human source 17.16% and animal source 0） （P 〈 0. 01 ）, so did the resistance rates of Salmonella with different sources to polymyxin E （ food source 8.30%, human source 27.94% and animal source 0. 78% ） （P 〈 0. 01 ）. Importantly, seven Salmonella strains showed co-resistance to polymyxin and the third-generation cephalosporins. Moreover, one Salmonella Typhimurium strain producing ESBLs isolated from human stool was mcr-1 gene positive and this gene was carried by a transferable plasmid. Conclusion This is the first report to identify a human original Salmonella strain carrying the mcr-lgene. Based on MIC distribution data in vitro, MIC of 8 ixg/ml was recommended as

关 键 词：多粘菌素 沙门菌 药物敏感性 mcr-1 

分 类 号：R446.5[医药卫生—诊断学]