广州地区ST17无乳链球菌的分子流行病学特征及快速鉴定  

Molecular epidemiological characteristics and rapid identification of Streptococcus agalactiae ST17 strains in Guangzhou

作　　者：程招敏[1,2] 柯培锋[1,2] 蓝锴[1,2] 周强[1,2] 曹楠楠[1,2] 秦笙[1,2] 张文[1,2] CHENG Zhao-min;KE Pei-feng;LAN Kai;ZHOU Qiang;CAO Nan-nan;QIN Sheng;ZHANG Wen(Guangdong Provincial Hospital of Chinese Medicine,Guangzhou,Guangdong 510120,China)

机构地区：[1]广东省中医院检验科,广东广州510120 [2]广州中医药大学第二临床学院,广东广州510120

出　　处：《中华医院感染学杂志》2020年第8期1210-1216,共7页Chinese Journal of Nosocomiology

基　　金：广东省中医药局科研基金资助项目(20181102)。

摘　　要：目的了解广州地区ST17无乳链球菌的分子流行病学特征,运用基质辅助激光解吸/电离飞行时间质谱(Matrix assisted laser desorption/ionization time of flight mass spectrometry,MALDI-TOF MS)建立其快速筛查方法。方法收集侵袭性无乳链球菌98株,进行多位点序列分型(Multilocus sequence typing,MLST)和分子血清学分型,进行药敏试验并检测红霉素和克林霉素耐药基因(ermB、ermA/E、ermTR和linB基因),运用MALDI-TOF MS分析ST17菌株的特征质谱峰。结果所有菌株被分为10个ST,来源于7个克隆群,其中ST17占16.3%。ST17菌株均为血清学Ⅲ型。ST17菌株对红霉素与克林霉素耐药率分别为93.8%和87.5%,检出ermB和mefA/E两种耐药基因,阳性率分别为100.0%和20.0%,未检出ermTR和linB基因。ST17菌株与非ST17菌株对红霉素和克林霉素耐药性以及ermB和mefA/E携带率的差异均具有统计学意义(P<0.05)。10种ST中,仅ST17在7620 Da处有特征质谱峰。结论广州地区流行的侵袭性无乳链球菌具有较高遗传多样性。ST17/血清学Ⅲ型菌株是该地区流行的主要侵袭性菌株之一,对红霉素和克林霉素耐药率高,红霉素耐药主要由ermB介导。MALDI-TOF MS可用于ST17菌株的快速筛查。OBJECTIVE To investigate the molecular epidemiological characteristics of Streptococcus agalactiae ST17 strains in Guangzhou,and to establish a rapid screening method for these strains by using matrix assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF MS). METHODS In this study, 98 invasive S. agalactiae strains were collected in Guangzhou. For all the strains, multilocus sequence typing(MLST) and molecular serotyping were performed. Antibiotic susceptibilities were tested, and all isolates were assessed for erythromycin and clindamycin resistance genes detection, respectively. MALDI-TOF MS was performed to discriminate ST17 strains from other sequence types strains. RESULTS All strains were divided into ten ST types, which were derived from seven clonal complexes. ST17 strains accounted for 16.3%, all of which were serotype Ⅲ. The erythromycin and clindamycin resistance rates of ST17 strains were 93.8% and 87.5%, respectively. The ermB and mefA/E genes were detected in ST17 strains, and the positive rates were 100.0% and 20.0%, respectively. ermTR and linB genes were not detected. There were significant differences in erythromycin and clindamycin resistance and the rate of carrying ermB and mefA/E genes between ST17 strains and non-ST17 strains(P<0.05). Among the 10 different ST strains, only ST17 strains had characteristic mass peak at 7620 Da. CONCLUSION The prevalent pathogenic S. agalactiae in Guangzhou has relatively high genetic diversity. ST17/serotype Ⅲ strain is one of the major invasive strains prevalent in the region with high resistance to erythromycin and clindamycin. And erythromycin resistance is mainly mediated by ermB gene. MALDI-TOF MS can be used for rapid screening of ST17 strains.

关 键 词：无乳链球菌 多位点序列分型 分子血清分型 耐药基因 基质辅助激光解吸/电离飞行时间质谱 

分 类 号：R378[医药卫生—病原生物学]