知识与财富的链接
目的 了解致骨关节感染金黄色葡萄球菌(SA)临床分离株的分子分型、毒力和耐药特征,为抗感染治疗提供依据。方法 收集2014年1月—2021年12月首都医科大学附属北京积水潭医院骨关节感染住院患者中分离的SA,基于全基因组测序对菌株进行多位点序列分型(MLST)和葡萄球菌A蛋白(Spa)分型,对耐甲氧西林葡萄球菌(MRSA)进行葡萄球菌染色体mec基因盒(SCCmec)分型;利用在线数据库分析菌株携带的毒力和耐药基因;采用全自动鉴定药敏仪进行抗菌药物敏感试验。结果 100株SA菌株中MRSA占比30.0%。共检测出22种ST型别和39种Spa型别,其中ST优势型为ST59(16.0%)和ST239(14.0%);Spa优势型为t437(13.0%)和t030(10.0%)。MRSA分离株的流行克隆是ST239-SCCmecⅢ-t030/t037(46.7%)。SA中生物被膜基因(icaA、icaB、icaC、icaD、icaR)、溶血素基因(hlb、hld、hlgA、hlgB、hlgC)、黏附素基因(clfA、clfB、fnbA、fnbB、ebp)和免疫逃逸基因(adsA、sbi、scn)普遍存在,检出率为89.0%～100.0%。MRSA中肠毒素基因seb(43.3%)、selk(93.8%)和selq(83.3%)检出率明显高于甲氧西林敏感金黄色葡萄球菌(MSSA)(P均<0.05)。在耐药特征上,SA中blaZ基因检出率最高(87.0%),MRSA分离株中erm(A)、tet(M)、aph(3′)-Ⅲ、ant(6)-Ⅰa、ant(9)-Ⅰa、aac(6′)-aph(2″)基因的检出率为43.3%～50.0%,显著高于MSSA(P均<0.05)。药敏试验结果显示,SA对青霉素、红霉素和克林霉素耐药率较高,分别为89.0%、67.0%和51.0%;MRSA对常见抗菌药物的耐药率明显高于MSSA(P均<0.05)。结论 我院骨关节感染中SA分子流行病学特点呈多样化,ST239-SCCmecⅢ-t030/t037是其常见流行克隆。MRSA与MSSA在耐药基因和耐药率上存在显著差异,应引起临床重视。
Abstract : Objective To investigate the molecular typing,virutlence ,and drug resistance characteristics of Staphylococcus aureus(SA) in lone and joint infections, providing basis for anti-infection treatment.Methods ''The SA strains isolated from inpatients withbone and joint infections in Beijing Jishuitan Hospital , CapitalMedlical University from January 2014 to December 2021 were collecterd.Muli-locus sequrence typing ( MILST) and Staphylococal A protein ( Spa) typing for all the strains and Staphylococcal cassette chromo-some mec ( SCCma. ) typing of methicillin-resistant Staphyloccus aureus ( MRSA) were performed basert on whole genome sequencing.The vinulence genes and drug resistance genes of the strains were identified by online database. The antimicrobial susceptibility testswere caried by automatic microbiological assay system.Results MRSA acounted for 30.0% of the 100 isolated strains of SA. A totalof 22 ST types and 39 Spa types were identified in the 100 strains of S.aureus , among which ST59 (16.0% ) and ST239 ( 14.0%) werethe dominant ST types,and t437 ( 13.0%) and t030 ( 10.0%） were the dominant Spa types. ST239-SCCmecⅢl-030/1037 clone(46.7%) was the main epidemic elone in MRSA isolates. The bioflm gene ( icaA, icaB , icaC, icaD , icaR) , hemolysin gene ( hlb,hld, hegA, hlgB, hgC'') , adhesion gene ( ePfA , cfB, fnbA , finbB, ebp ) , and immume escape gene ( adsA, si , scn) were widespreadin all SA strains, with detection rates ranging from 89.0% to 100.0%. The detection rates of enterotoxin genes seb ( 43.3% ) , selk(93.8% ） and selq ( 83.3%) inMRSA were significamly higher than those in methicillin-sensitive Staphylococus aureus ( MSSA) ( allP<0.05). In tems of drug-resistance chanacteristics , the detection rate of the resistance gene blaZ (87.0%) was the highest among allthe S.aureus strains. In the isolated MBSA strains , the detection rate of resistance genes for erm( A ) , tet( M) , aph(3'')-Ⅲ, an(6)-la,ant(9)-la,and aae(6'')-aph(2") ranged from 43.3% to 50.0%,which were significantly higher than those in MSSA ( all P<0.05 ).The results of the drug-sensitivity test showed that the resistant rates of S. aureus strains to penicillin,erythromycin,and clindamycin were relatively high ( 89.0%,67.0% , and 51.0% ,respectively). The resistant rates of MRSA to the antimicrobial agents commonlyused in clinical practice were significantly higher than those of MSSA ( all P<0.05). Conclusion The molecular epidemiological char-acteristics of SA strains isolated from bone and joint infections were diversified in our hospital. ST239-SCCme ⅢI-t030/1037 was themost common epidemic clone among the strains. There were significant differences in the resistance genes and drug resistance rates be-tween MRSA and MSSA strains,for which clinical altention should be paid.
