金黄色葡萄球菌在人工关节感染中的分子型别与耐药基因特征

Molecular types and drug resistance gene characteristics of Staphylococcus aureus in periprosthetic joint infection

目的探讨导致人工关节假体周围感染(PJI)的金黄色葡萄球菌的抗菌药物耐药率、耐药基因和分子型别,为抗感染治疗提供依据和流行病学信息。方法收集2017年1月至2022年1月该院80例髋膝PJI患者关节液及假体周围组织中分离的金黄色葡萄球菌,进行抗菌药敏试验,分析其对骨科常用抗菌药物的耐药率;对菌株进行全基因组测序和生物信息学分析,研究其耐药基因携带情况;采用多点位序列分型(MLST)进行菌株分型和系统发育分析,比较主要流行分子型别对抗菌药物的耐药差异。结果该研究共收集80株金黄色葡萄球菌,耐甲氧西林金黄色葡萄球菌(MRSA)检出率为26.25%,甲氧西林敏感金黄色葡萄球菌(MSSA)检出率为73.75%。耐药性分析结果显示,MRSA对红霉素、克林霉素、氟喹诺酮类药物和四环素的耐药率较高,未发现对万古霉素、利奈唑胺和替加环素耐药菌株。95%的金黄色葡萄球菌携带耐药基因,其中β-内酰胺类耐药基因检出率最高(92.50%)。MRSA平均携带4.3种耐药基因,MSSA平均携带2.2种。金黄色葡萄球菌小菌落变异体(SCVs)检出率为23.75%。MLST结果显示,PJI中金黄色葡萄球菌主要流行克隆复合物型别为ST-398型(22.50%)、ST-5型(13.75%)和ST-59型(11.25%)。ST-59型金黄色葡萄球菌的万古霉素最低抑菌浓度相对较高。结论万古霉素、利奈唑胺可作为PJI中抗MRSA感染的主要选择;PJI中金黄色葡萄球菌SCVs检出率较高;ST-398、ST-5、ST-59型是该院PJI金黄色葡萄球菌的主要流行克隆菌株,应针对不同金黄色葡萄球菌克隆类型采取个性化抗感染治疗策略。

Objective To investigate the antimicrobial resistance rate,drug resistance genes and molecular types of Staphylococcus aureus in periprosthetic joint infection(PJI),and to provide evidence and epidemiological information for anti-infection treatment.Methods The Staphylococcus aureus isolated from the synovial fluid and periprosthetic tissues of 80 patients with hip and knee PJI in the hospital from January 2017 to January 2022 were collected for antimicrobial sensitivity test,and the drug resistance rate of Staphylococcus aureus to commonly used antibiotics in orthopedics was analyzed.Whole genome sequencing and bioinformatics analysis were performed to investigate the prevalence of drug resistance genes.Multipoint sequence typing(MLST)was used for typing and phylogenetic analysis,and the differences in antimicrobial resistance among the main molecular types were compared.Results A total of 80 strains of Staphylococcus aureus were collected in this study.The detection rate of methicillin-resistant Staphylococcus aureus(MRSA)was 26.25%,and the detection rate of methicillin-sensitive Staphylococcus aureus(MSSA)was 73.75%.The results of drug resistance analysis showed that MRSA had high resistance rates to erythromycin,clindamycin,fluoroquinolones and tetracycline,and no strains resistant to vancomycin,linezolid,and tigecycline were found.95%of Staphylococcus aureus carried drug resistance genes,and the detection rate ofβ-lactam resistance genes was the highest(92.50%).MRSA and MSSA carried 4.3 and 2.2 drug resistance genes on average.The detection rate of small colony variants(SCVs)in Staphylococcus aureus was 23.75%.MLST results showed that the main clonal complex types of Staphylococcus aureus in PJI were ST-398(22.50%),ST-5(13.75%)and ST-59(11.25%).The minimal inhibitory concentration of vancomycin in ST-59 Staphylococcus aureus was relatively high.Conclusion Vancomycin and linezolid can be used as the main choice for anti-MRSA infection in PJI.The detection rate of Staphylococcus aureus SCVs in PJI is high.ST-398,ST-5 and ST-59 were the main epidemic clones of Staphylococcus aureus in PJI in this hospital.Individualized anti-infection treatment strategies should be taken according to different Staphylococcus aureus clones.