曹阳, 遇晓杰, 韩营营, 李杰, 阚飙, 闫梅英. 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[J]. 疾病监测, 2017, 32(5): 365-371. DOI: 10.3784/j.issn.1003-9961.2017.05.005
引用本文: 曹阳, 遇晓杰, 韩营营, 李杰, 阚飙, 闫梅英. 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[J]. 疾病监测, 2017, 32(5): 365-371. DOI: 10.3784/j.issn.1003-9961.2017.05.005
CAO Yang, YU Xiao-jie, HAN Ying-ying, LI Jie, KAN Biao, YAN Mei-ying. Polymyxin resistance and mcr-1 prevalence in non-typhoid Salmonella isolates in China[J]. Disease Surveillance, 2017, 32(5): 365-371. DOI: 10.3784/j.issn.1003-9961.2017.05.005
Citation: CAO Yang, YU Xiao-jie, HAN Ying-ying, LI Jie, KAN Biao, YAN Mei-ying. Polymyxin resistance and mcr-1 prevalence in non-typhoid Salmonella isolates in China[J]. Disease Surveillance, 2017, 32(5): 365-371. DOI: 10.3784/j.issn.1003-9961.2017.05.005

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

  • 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0.125 g/ml至16 g/ml,对多粘菌素B的MIC50、MIC90分别为1 g/ml和8 g/ml;对多粘菌素E的MIC50、MIC90分别为2 g/ml和8 g/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8 g/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%(P0.01);对多粘菌素E的耐药率分别为8.30%、27.94%和0.78%(P0.01)。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8 g/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。

     

    Abstract: 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 g/ml to 16 g/ml. The MIC50 and MIC90 of polymyxin B were 1 g/ml and 8 g/ml, respectively. While the MIC50 and MIC90 of polymyxin E were 2 g/ml and 8 g/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 g/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) (P0.01), 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%) (P0.01). 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-1 gene. Based on MIC distribution data in vitro, MIC of 8 g/ml was recommended as the resistant breakpoints to polymyxin B and colistin for non-typhoid Salmonella in China. The prevalence of polymyxin resistance was low, but it is not negligible. The antimicrobial resistance surveillance for Salmonella from different sources should be strengthened.

     

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