CAMP阴性无乳链球菌的鉴定及耐药特征  

Identification and resistance characteristics of CAMP-negative Streptococcus agalactiae

作　　者：王秀 冷贵云 唐伟 周强[1] Wang Xiu;Leng Guiyun;Tang Wei;Zhou Qiang(Dept of Clinical Laboratory,The Second Affiliated Hospital of Anhui Medical University,Hefei 230601)

机构地区：[1]安徽医科大学第二附属医院检验科,合肥230601

出　　处：《安徽医科大学学报》2025年第1期142-146,共5页Acta Universitatis Medicinalis Anhui

基　　金：国家自然科学基金(编号:82102460);安徽医科大学校科研基金(编号:2021xkj050);安徽省转化医学研究院科研基金(编号:2021zhyx-C47)。

摘　　要：目的探究CAMP阴性无乳链球菌的鉴定及耐药特征。方法应用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)和CAMP试验,鉴定33株疑似无乳链球菌。16S rDNA验证CAMP阴性菌株;实时荧光定量聚合酶链式反应(qPCR)检测CAMP阴性菌株的cfb基因;微量肉汤稀释法进行药敏检测,对比CAMP阴性和阳性菌株的耐药率。结果MALDI-TOF MS鉴定显示,33株均为无乳链球菌。CAMP试验表明,其中7株阴性,经16S rDNA完成菌株验证。这7株的qPCR结果显示,只有1株检出cfb,为阳性。药敏报告显示,CAMP阴性和阳性菌株对青霉素G、头孢吡肟、头孢噻肟、万古霉素和利奈唑胺均敏感,前者对氯霉素和四环素的耐药率(28.57%、85.71%)略高于后者(15.38%、57.69%),对莫西沙星、左氧氟沙星和红霉素的耐药率(14.29%、14.29%、42.86%)略低于后者(34.62%、34.62%、57.69%),但差异无统计学意义。结论CAMP阴性无乳链球菌的耐药性无异于CAMP阳性菌株,但传统的CAMP试验和只针对cfb的qPCR的鉴定,容易造成临床漏检。MALDI-TOF MS是一项快速、简便、准确的鉴定技术,值得推广。Objective To explore identification and resistance characteristics of CAMP-negative Streptococcus agalactiae.Methods Using matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF MS)and the CAMP assay,33 presumptive strains of Streptococcus agalactiae were identified.The CAMP-negative strains were further validated through 16S rDNA,while the CAMP factor encoding gene(cfb)was detected using real-time fluorescence quantitative polymerase chain reaction(qPCR).Antimicrobial susceptibility testing was conducted using the microbroth dilution method,and the resistance rates of CAMP-negative and CAMP-positive strains were compared.Results Based on MALDI-TOF MS identification,all 33 strains were classified as Streptococcus agalactiae.Among them,7 strains tested negative for CAMP were subsequently confirmed as Streptococcus agalactiae through 16S rDNA.The qPCR results indicated that,only 1 strain showed cfb presence.The CAMP-negative and CAMP-positive strains were sensitive to penicillin G,cefepime,cefotaxime,vancomycin,and linezolid.The resistance rates of the former to chloramphenicol and tetracycline(28.57%,85.71%)were slightly higher than the latter(15.38%,57.69%),while the resistance rates to moxifloxacin,levofloxacin,and erythromycin(14.29%,14.29%,42.86%)were slightly lower than the latter(34.62%,34.62%,57.69%),but was not significant.Conclusion Drug risistance of CAMP-negative Streptococcus agalactiae is the same as CAMP-positive strains,but traditional CAMP assay and cfb-targeted qPCR can result in missed detections.MALDI-TOF MS offers a quick,simple,and accurate identification method that merits wider adoption.

关 键 词：无乳链球菌 基质辅助激光解吸电离飞行时间质谱 CAMP试验 16S rDNA 荧光定量聚合酶链式反应 CFB 

分 类 号：R378.12[医药卫生—病原生物学] Q93-331[医药卫生—基础医学] R446.5[生物学—微生物学]