临床分离表皮葡萄球菌耐药性分析及毒力基因研究

Analysis of antimicrobial resistance and virulence genes in clinical isolates of Staphylococcus epidermidis

目的进一步明确临床分离得到的表皮葡萄球菌毒力及耐药基因的携带情况,并探讨其与耐药性的关系,为临床抗感染治疗提供理论依据。方法收集2019年1月—2022年1月上海市奉贤区中心医院临床样本中非重复分离的表皮葡萄球菌82株,采用Microflex LT/SH微生物质谱鉴定仪及Vitek2-Compact全自动微生物分析仪进行细菌鉴定和药敏分析,聚合酶链反应(PCR)筛查生物膜相关基因icaA、bhp、IS256以及耐药基因mecA、ermC、aac(6')/aph(2")、aph(3')-Ⅲ,并分析毒力及耐药基因携带与临床常用抗感染治疗药物耐药性之间的关系。结果82株表皮葡萄球菌,主要来自于新生儿科(18/82,21.95%),肾内科(10/82,12.19%),急诊科(8/82,9.76%)和骨科(6/82,7.30%);以血液,分泌物,尿液来源为主(61/82,74.38%)。82株表皮葡萄球菌中,icaA检出率为18.29%(15/82),bhp检出率为25.61%(21/82),IS256检出率为20.73%(17/82),mecA检出率为70.73%(58/82),ermC检出率为29.27%(24/82)、aac(6')/aph(2")检出率为31.71%(26/82)、aph(3')-Ⅲ检出率为13.41%(11/82)。生物膜相关基因IS256阳性菌株对苯唑西林、克林霉素、莫西沙星、甲氧苄啶/磺胺甲噁唑、庆大霉素和利福平具有更高的耐药率(P<0.05)。检出mecA阳性株58株(70.73%)。82株表皮葡萄球菌对青霉素、苯唑西林、红霉素耐药率均高于60%,并未发现万古霉素、替加环素、利奈唑胺或呋喃妥因耐药菌株。结论本研究临床分离表皮葡萄球菌mecA携带率较高,生物膜相关基因IS256与细菌耐药性密切相关。

Objective To further clarify the virulence and drug resistance genes of Staphylococcus epidermidis isolated from the clinic,and explore the relationship between these genes and drug resistance to provide theoretical basis for clinical anti-infective treatment.Methods 82 isolates of S.epidermidis that were not duplicated in clinical samples collected from Fengxian District Central hospital of Shanghai from January 2019 to January 2022 were collected.Bacterial identification was performed by using Microflex LT/SH microbial mass spectrometry and antimicrobial sensitivity analysis was performed by usingVitek2-Compact automatic microbial analyzer.Polymerase chain reaction(PCR)was used to detect biofilm-related genes icaA,bhp,IS256 and antimicrobial resistance genes mecA,ermC,aac(6')/aph(2"),aph(3')-III,and to analyze the relationship between virulence gene,antimicrobial resistance genes and antimicrobial agents that commonly used in clinical anti-infective therapeutics.Results The 82 isolates of S.epidermidis were mainly from neonatology department(18/82,21.95%),nephrology department(10/82,12.19%),emergency department(8/82,9.76%)and orthopedics department(6/82,7.30%).The main sources were blood,secretion and urine(61/82,74.38%).Among the 82 isolates of S.epidermidis,the detection rate of icaA,bhp,IS256 and mecA were 18.29%(15/82),25.61%(21/82),20.73%(17/82)and 70.73%(58/82),respectively.The detection rate of ermC was 29.27%(24/82),that of aac(6')/aph(2")was 31.71%(26/82),and that of aph(3')-III was 13.41%(11/82).Biofilm-related gene IS256 positive isolates had higher resistance rates to benzacillin,clindamycin,moxifloxacin,trimethoprim/sulfamethoxazole,gentamicin and rifampicin(P<0.05).MecA positive isolates were detected in 58 isolates(70.73%).The resistance rates of 82 isolates of S.epidermidis to penicillin,benzacillin and erythromycin were all above 60%,and no isolate of resistant to vancomycin,tegacycline,linezolid or nitrofurantoin was found.Conclusions In this study,the mecA carrying rate of S.epidermidis was high,and the biofilm-related gene IS256 was closely related to bacterial resistance.