陕西省和上海市市售猪肉中金黄色葡萄球菌分子多样性及耐药性研究

Molecular diversity and drug resistance of Staphylococcus aureus from retail pork in Shaanxi Province and Shanghai City

中文关键词:  猪肉  金黄色葡萄球菌  分子特征  耐药性

英文关键词:pork  Staphylococcus aureus  molecular characteristics  antimicrobial susceptibility

中文摘要:

      目的 了解陕西省和上海市市售猪肉中金黄色葡萄球菌的分子多样性和耐药性。方法 对分离于陕西省和上海市的110株猪肉源金黄色葡萄球菌进行15种抗生素耐药性、26种耐药基因、23种毒力编码基因及金黄色葡萄球菌A蛋白A (Staphylococcus aureus protein A, SPA)分型和多位点序列分型(multilocus sequence typing, MLST)检测。结果 药敏结果显示, 菌株对β-内酰胺类和叶酸代谢途径抑制剂的耐药性最为普遍, 其次为四环素和大环内酯类抗生素。其中β-内酰胺类抗生素耐药相关基因主要为blaZ、四环素类抗生素耐药相关基因主要为tetK和大环内酯类抗生素耐药相关基因主要为ermB和ermC。分离株耐药性受采样地点和耐药基因影响, 分离自上海市分离菌株较陕西省分离株耐药更为严重(P<0.01)。此外, 还检测到2株耐甲氧西林金黄色葡萄球菌菌株。23种被检毒力编码基因中有18种毒力编码基因被检出, 其中seg、sei、sem、sen、seo、seu、sea、sep、sed、sej、ser基因携带率较高。陕西省毒力编码基因的携带率85% (34/40)显著高于上海市27.1% (19/70), 其中经典肠毒素编码基因的携带率分别为65.0% (22/40)和10.0% (10/70)。所有分离株共有31种克隆型, 陕西省的主导分子型为ST6-t701 (22.5%, 9/40), 上海市的主导分子型为ST3055-t084 (31.4%, 22/70)。此外, 分离株携带肠毒素编码基因与分子型有相关性, 如ST6-t701高度携带sea, ST7-t091主要携带sep, ST5-t002主要携带seg-sei-sem-sen-seo-seu。结论 市售猪肉中金黄色葡萄球菌耐药严重, 携带肠毒素编码基因较多, 可能通过食物链进行传播。

英文摘要:

      Objective To investigate the molecular diversity and antibiotic resistance of Staphylococcus aureus from retail pork in Shaanxi Province and Shanghai City. Methods Totally 110 strains of Staphylococcus aureus isolated from retail pork in Shaanxi Province and Shanghai City were characterized by 15 kinds of common antibiotics, 26 kinds of resistance genes, 23 kinds of virulence coding genes, staphylococcal protein A (SPA) and multilocus sequence typing (MLST). Results Antimicrobial susceptibility testing results showed that the isolates were most commonly resistant to β-lactam antibiotics and folate metabolism inhibitor, followed by macrolides and tetracyclines. The resistance related genes of β-lactam antibiotics were mainly blaz, tetracycline antibiotics were mainly tetk and macrolide antibiotics were mainly ermB and ermC. The resistance of the isolates was influenced by the sampling location and the drug resistance genes, and the isolates from Shanghai were more severely resistant than the isolates from Shaanxi Province (P<0.01). In addition, 2 strains of methicillin-resistant Staphylococcus aureus were detected. Eighteen kinds of virulence coding genes were detected by PCR for 23 virulences coding genes. Seg, sei, sem, sen, seo, seu, sea, sep, sed, sej and ser genes were frequently detected. The carrying rate (85%, 34/40) of virulence coding genes in Shaanxi Province was significantly higher than that in Shanghai (27.1%, 19/70). In addition, the carrying rate of classical enterotoxin genes was 65.0% (22/40) and 10.0% (10/70) in Shaanxi Province and Shanghai City, respectively. There were 31 kinds of clonal types in all isolates. The dominant molecular type was ST6-t701 (22.5%, 9/40) and ST3055-t084 (31.4%, 22/70) in Shaanxi Province and in Shanghai, respectively. In addition, virulence coding genes were correlated with molecular phenotypes among the isolates. For example, ST6-t701 highly carried sea, ST7-t091 mainly carried sep, and ST5-t002 mainly carried seg-sei-sem-sen-seo-seu. Conclusion Staphylococcus aureus from retail pork has serious drug resistance and carries more virulence coding genes, which may be transmitted through the food chain.