2015年分离自中国大陆食品的1 070株沙门菌耐药性分析

目的 了解我国2015年食源性沙门菌的耐药状况及mcr-1基因在硫酸粘菌素(conlistin,CT)耐药菌株中的分布情况。方法 采用微量肉汤稀释法测定1 070株食源性沙门菌对10类16种抗生素的药物敏感性,采用荧光定量聚合酶链式反应(PCR)方法检测196株CT耐药菌株中是否存在mcr-1基因。结果 71.9%(769/1 070)的沙门菌对受试的16种抗生素呈现不同程度的耐药性,其中萘啶酸(NAL)、四环素(TET)、氨苄西林(AMP)、氨苄西林/舒巴坦(SAM)4种抗生素的耐药率较高,均在40%以上,未见碳青霉烯类耐药菌株,47.5%(508/1 070)的沙门菌同时耐受3类或3类以上抗生素,表现为多重耐药,同时耐受抗生素种类最高为9类。共存在141种耐药谱,优势耐药谱型为NAL、AMP-SAM-NAL-CT和TET。196株CT耐药沙门菌检出1株携带mcr-1基因且超广谱β-内酰胺酶(ESBLs)阳性的菌株,该菌株为伦敦血清型,是所有测试菌株中唯一1株九重耐药株。部分省份沙门菌耐药率较高。生禽肉和生畜肉来源沙门菌耐药率较高,分别为80.6%(349/433)和73.5%(283/385)。结论 我国2015年食源性沙门菌整体耐药水平较高,且多重耐药情况严重,生禽畜肉是耐药沙门菌的主要来源,我国食源性沙门菌中存在携带mcr-1基因的严重耐药菌株,应引起关注。

Resistance analysis of 1 070 Salmonella strains isolated from food sample in mainland China, 2015

Objective To understand the antimicrobial resistance of foodborne Salmonella isolates in China in 2015, and to obtain the prevalence of mcr-1 gene in colistin(CT)resistant isolates. Methods Broth microdilution method was used for antimicrobial susceptibility test of 1 070 Salmonella strains against 16 antimicrobial compounds which belonged to 10 categories, and 196 colistin resistant strains were detected for the existence of mcr-1 gene by real-time fluorescence quantitative polymerase chain reaction(PCR). Results About 71.9% (769/1 070) of the isolates showed different antimicrobial resistant levels to 16 antimicrobials, and the resistance rates to nalidixic acid(NAL), tetracycline(TET), ampicillin(AMP) and ampicillin-sulbactam(SAM) were as high as above 40%, while all strains were susceptible to carbapenems. 47.5% (508/1 070) of them were identified as multi-drug resistant (MDR) strains and were resistant to as much as nine classes of antimicrobials. There were 141 antimicrobial resistance spectrums with NAL, AMP-SAM-NAL-CT and TET as the top three spectrums. One strain of mcr-1 gene and ESBLs positive which was identified as Salmonella enterica subsp. enterica ser. London had been detected in 196 colistin resistant isolates and it was the only one strain with resistance against nice categories of antimicrobials. Serious multi-drug resistance was found in some provinces and strains recovered from raw poultry meat were detected to be the worst with resistant rate of 80.6%(349/433), followed by isolates from raw livestock meat (73.5%, 283/385). Conclusion An overall high level antimicrobial resistance was found among foodborne Salmonella isolates in China in 2015, so was the MDR condition, especially for strains recovered from some provinces and from raw poultry and livestock meat. Mcr-1 gene could be carried in foodborne Salmonella isolates recovered from China, therefore, close attention should be paid to its surveillance.