基质辅助激光解吸/电离飞行时间质谱仪快速鉴别青霉素耐药及敏感的肺炎链球菌的应用

目的 探讨基质辅助激光解吸/电离飞行时间质谱仪（matrix-assisted laser desorption/ ionization time of flight mass spectrometry,MALDI-TOF MS）快速鉴别青霉素耐药及青霉素敏感的肺炎链球菌的可行性。方法 收集2017年1月到2019年12月广州市番禺区中心医院青霉素耐药的肺炎链球菌（PRSP）10株及青霉素敏感的肺炎链球菌（PSSP）30株。其中31株肺炎链球菌分离自呼吸道标本,占77.5%,18株肺炎链球菌分离自儿科,占45.0%。年龄分布,60岁以上15株,12岁以下18株。用MALDI-TOF MS进行菌株鉴定,用VITEK 2 Compact的药敏卡AST-GP68进行耐药性检测,用VITEK MS的Launch pad软件对MALDI-TOF MS鉴定的肺炎链球菌所产生的质谱峰图进行分析。结果 质谱峰m/z的3992、4419为肺炎链球菌的特征峰,质谱峰m/z的 3853、4218、4619是用于区分PRSP及PSSP最主要的特征峰,不同菌株质谱峰略有不同。164株肺炎链球菌青霉素的耐药率为8.5%,万古霉素﹑利奈唑胺﹑厄他培南的敏感率均为100.0%。90株PSSP及64株PRSP对15种抗生素的药敏结果显示,PSSP的阿莫西林及青霉素的敏感率分别为100.0%,而PRSP的阿莫西林及青霉素的敏感率为0。结论 MALDI-TOF MS可快速准确鉴别PRSP及PSSP,具有耗时短,灵敏度高,特异性好等特点。

Application of matrix-assisted laser desiolation/ionization time of flight mass spectrometer in identifying penicillin-resistance and penicillin-sensitive Streptococcus pneumoniae

Objective To explore the feasibility of a matrix-assisted laser desorption/ionization time of flight mass spectrometer(MALDI-TOF MS)to quickly identify penicillin resistance and penicillin-sensitive Streptococcus pneumoniae.MethodsA total of 10 strains of penicillin-resistant Streptococcus pneumoniae(PRSP)and 30 strains of penicillin-sensitive Streptococcus pneumoniae(PSSP)(31 strains of streptococcus isolated from respiratory tracts accounting for 77.5%,and 18(45.0%)strains isolated from Department of Pediatrics)were collected in Panyu District Central Hospital,Guangzhou,Jan.2017-Dec.2019.Age distribution,15 strains were from over 60 years old,and 18 strains were from under 12 years old.All strains identified with MALDI-TOF MS,VITEK 2 Compact’s drug-sensitive card AST-GP68 was used for drug resistance testing,and the mass spectra of Streptococcus pneumoniae identified by MALDI-TOF MS were analyzed by Launch pad software of VITEK MS.ResultsThe mass spectrometry peak m/z of 3992,4419 were the characteristic peak of Streptococcus pneumoniae,and the mass spectrometry peak m/z of 3853,4218,4619 was used to distinguish the most important characteristic peaks of PRSP and PSSP.The mass spectrometry peak skewed of different strains was slightly different.The resistance rate of penicillin in 164 strains of Streptococcus pneumoniae was 8.5%,the sensitivity rates of vancomycin,linezolid and ertapenem were 100.0%.The sensitivity of 90 PSSP and 64 PRSP strains to 15 kinds of antibiotics showed that the sensitivity rates of amoxicillin and penicillin in PSSP were 100.0%,while the sensitivity rates of amoxicillin and penicillin in PRSP were 0.Conclusion MALDI-TOF MS can quickly and accurately identify PRSP and PSSP,which is short-time-consuming,highsensitivity and good specificity.