风心病术后获得性耐甲氧西林金黄色葡萄球菌感染机制研究

A study on the mechanism by which methicillin-resistant Staphylococcus aureus infecting postoperative patients with rheumatic heart disease develops drug resistance

目的分析风心病患者术后感染耐甲氧西林金黄色葡萄球菌SCCmec基因型别及耐药情况,为不同感染型别耐甲氧西林金黄色葡萄球菌的治疗提供指导。方法收集2015年1-12月风心病术后患者临床资料,对从患者临床标本中分离出的耐甲氧西林金黄色葡萄球菌进行SCCmec基因检测,K-B法分析不同基因型别菌株的耐药情况。结果63株耐甲氧西林金黄色葡萄球菌中,59株检测到SCCmecⅢ型基因,4株检测到SCCmecⅡ型基因。下呼吸道痰液标本分离耐甲氧西林金黄色葡萄球菌39株,其中携带SCCmecⅢ型基因37株,占94.87%,携带SCCmecⅡ型基因2株,占5.13%;血液标本分离18株,其中携带SCCmecⅢ型基因16株,占88.88%,携带SCCmecⅡ型基因2株,占11.12%;腹水以及伤口分泌物标本分别分离4和2株,均携带SCCmecⅢ型基因。携带SCCmecⅢ型基因的耐甲氧西林金黄色葡萄球菌对氨苄西林、左氧氟沙星、环丙沙星、庆大霉素、氯霉素和利福平等的耐药率分别为100.00%、49.15%、37.29%、33.90%、10.17%和8.47%,对万古霉素和利奈唑胺仍然敏感;携带SCCmecⅡ型基因的耐甲氧西林金黄色葡萄球菌对氨苄西林、左氧氟沙星、环丙沙星、庆大霉素、利福平的耐药率分别为100.00%、50.00%、25.00%、25.00%、25.00%,对氯霉素、万古霉素和利奈唑胺仍然敏感。结论耐甲氧西林金黄色葡萄球菌临床分离株基因型以SCCmecⅢ型为主,抗感染治疗时应首选万古霉素和利奈唑胺。

Objective To type SCCmec genes and to analyze the drug resistance of methicillin-resistant Staphylococcus aureus infecting postoperative patients with rheumatic heart disease in order to guide the treatment of infections with dif- ferent types of methicillin-resistant S. aureus. Methods Clinical data on postoperative patients with rheumatic heart disease were collected from January to December 2015. SCCmec genes of methicillin-resistant S. aureus were detected, and the drug resistance of strains with different types of those genes was analyzed using the K-B method. Results Six- ty-three strains of methicillin-resistant S. aureus were identified. Of those, 59 had an SCCmec type III gene and 4 had an SCCmec type II gene. Thirty-nine strains of methicillin-resistant S. aureus were isolated from samples of sputum from the lower respiratory tract. Of those, 37 had an SCCmec type III gene （94. 87%） and 2 had an SCCmec type II gene （5.13 %）. Eighteen strains of methicillin-resistant S. a ureus were isolated from blood samples. Of those, 16 had an SCC- mec type III gene （88.88%） and 2 had an SCCmec type II gene （11.12%）. Four strains of methicillin-resistant S. aureus were isolated from the ascitic fluid samples and 2 strains from wound secretions, and all 4 had an SCCmec type III gene. Methicillin-resistant S. aureus with an SCCmec type III gene had resistance to ampicillin of 100.00%, resistance to levo- floxacin of 49.15 %, resistance to ciprofloxacin of 37.29%, resistance to gentamycin of 33.90%, resistance to chloram- phenicol of 10.17%, and resistance to rifampin of 8.47%. However, methicillin-resistant S. aureus with an SCCmec type III gene was sensitive to vancomycin and linezolid. Strains with an SCCmec type II gene had resistance to ampicillin of 100.00%, resistance to levofloxacin of 50.00%, resistance to ciprofloxacin of 25.00%, resistance to gentamycin of 25.00%, and resistance to rifampin of 25.00%, but strains were sensitive to chloramphenicol, vancomycin, and linezolid. Conclusion Clinical isolates of melhicillin-resistant S. aureus primarily had an SCCmec type III gene, and the use of wmcomycin and linezolid should be prioritized in the clinical treatment of infections with methicillin-resistant S. aureus.