广州市售生猪肉中金黄色葡萄球菌检测及其耐药性研究

Isolation and Antimicrobial Susceptibilities of Staphylococcus aureus in Commercially Available Raw Pork in Guangzhou

摘要:

了解广州市某区猪肉中金黄色葡萄球菌的污染情况、分子分型及其耐药性特征。根据GB 4789.10-2010对样品进行金黄色葡萄球的分离及鉴定，用多位点序列分型法进行分子分型，纸片扩散法进行抗生素敏感试验，采用PCR法验证MRSA并筛选检测I类整合子及相关耐药基因盒。110份生猪肉样品中有34份样品检出金黄色葡萄球菌（30.9%），得到34株该菌，所有菌株共可分成7种序列分型（sequence types，STs），分别为ST6（1/34）、ST7（16/34）、ST9（9/34）、ST59（1/34）、ST239（4/34）、ST2259（2/34）及一株等位基因谱为5-4-1-4-4-6-53的新型ST，34株金黄色葡萄球菌对12种抗生素耐药率分别为对青霉素100%耐药，对四环素、甲氧苄胺嘧啶、红霉素、克林霉素的耐药率分别为88.2%、76.5%、64.7%、61.8%，MRSA检出率为38.3%（13/34），I类整合子的检测率为14.7%（5/34）,其中2株菌携带相应基因盒。本次实验显示生猪肉中金黄色葡萄球菌污染比较严重且具有严重的抗生素耐药现象，ST7为主要的序列型号，I类整合子存在于食源性金黄色葡萄球菌中，相关基因盒对菌株耐药发挥作用。

Abstract:

The contamination situation, molecular typing and resistance characteristics of Staphylococcus aureus from pork were investigated. S. aureus were separated and identified according to GB 4789.10-2010, MLST method was used for molecular classification, drug susceptibility was tested by disc diffusion assay, and the class one integron, integrated gene cassettes and MRSA were examined by PCR. A total of 110 samples were examined and 34 of which (30.9%) were positive for S. aureus. All strains were divided into seven kinds of STs type, namely ST6( 1/34 ), ST7( 16/34), ST9( 9/34 ), ST59( 1/34 ), ST239( 4/34 ), ST2259( 2/34 ), and one new ST typing. All 34 S. aureus isolates were resistant to penicillin, and the drug resistant rate of tetracycline, trimethoprim, erythrocin, clindamycin, were 88.2%, 76.5%, 64.7%, 61.8%, respectively. 38.3% (13/34) of S. aureus were MRSA, 5 S. aureus isolates were observed as class one integron, and 2 isolates carried integrated gene cassettes. The results showed that raw pork were severely contaminated with S.aureus, and the isolates had serious antimicrobial resistance phenomenon, ST7 was the main sequence typing, the class one integron were existed in foodborne S. aureus, and the integrated gene cassettes played a role in resistant mechanism of isolates.