苏州市食源性金黄色葡萄球菌耐药分析及基因分型

目的 对苏州市2014~2017年分离的食源性金黄色葡萄球菌进行耐药谱和分子分型分析, 初步建立PFGE(pulsed-field gel electrophoresis)分型数据库。方法 采用微量肉汤稀释法检测金黄色葡萄球菌(Staphylococcus aureus, SAU)对19种常用的抗生素的耐药性, 采用Sma I进行酶切, 脉冲场凝胶电泳进行分子分型。菌株指纹图谱用BioNumerics v6.6软件进行分析。结果 81株SAU中检出10株耐甲氧西林金黄色葡萄球菌(methicillin-resistance Staphylococcus aureus, MRSA), 检出率12.3%。有72株菌存在不同程度的耐药, 耐药率达到88.9%, 其中对青霉素的耐药率最高(82.7%), 其次是氨苄西林(66.7%), 其后是克林霉素和红霉素(均为50.6%)。耐受3种和3种以上药物的多重耐药菌株共38株, 多重耐药率达46.9%。MRSA的多重耐药率高于甲氧西林敏感型金黄色葡萄球菌(methicillin-sensitive Staphylococcus aureus, MSSA), 差异具有统计学意义(P<0.05)。除8株菌不可被PFGE分型外, 其余73株菌可以被分为37个不同型别, 其中有4个优势型别共27株菌, 在可分型菌株中占比达37.0%。这些同源菌株分离自不同时间和地点, 有些还存在一定程度的变异。结论 食源性金黄色葡萄球菌耐药现象普遍存在, 多重耐药率较高, PFGE型别较为多样但有优势型别存在, 耐药谱和PFGE型别关联性较差。

Antimicrobial resistance analysis and genotyping of foodborne Staphylococcus aureus in Suzhou

Objective To analyze antimicrobial resistance and genotyping of foodborne Staphylococcus aureus (SAU) isolated from Suzhou city from 2014 to 2017 and preliminary establish a pulsed-field gel electrophoresis (PFGE) typing database. Methods Staphylococcus aureus strains were tested against 19 commonly used antibiotics by broth micro-dilution method. Genotyping was performed by pulsed-field gel electrophoresis and the cutting enzyme was Sma I. The fingerprints of the isolates were analyzed by BioNumerics software v6.6. Results Ten isolates (12.3%) of all the 81 strains were methicillin-resistant Staphylococcus aureus (MRSA). Totally 72 strains (88.9%) were antibiotic resistant in different degree, and the resistant rate to penicillin was the highest (82.7%), followed by ampicillin (66.7%), and the third place was clindamycin and erythromycin (both 50.6%). Overall, 38 (46.9%) strains were resistant to 3 or more antibiotics. The multi-drug resistance rate of MRSA was statistically significantly higher than that of methicillin-sensitive Staphylococcus aureus (P<0.05). PFGE grouped 73 isolates into 37 different patterns and 8 isolates could not be digested by Sma I. Of 37 patterns, there were 4 dominant types containing a total of 27 strains, constituting 37% of all isolates. These homologous strains were isolated from different time and place, and some of them had some degree of variation. Conclusion Antibiotic resistance among Staphylococcus aureus was prevalent. The multi-drug resistance rate of SAU to antibiotics was high. PFGE types were diverse but there were dominant types, and they had poor relevance to resistance spectrums.