MALDI-TOF MS检测临床复合群菌种及常规方法难鉴定菌种的应用性探讨

Application of MALDI-TOF MS to the identification of clinical composite flora and conventional methods

目的探讨基质辅助激光解析电离飞行时间质谱(matrix-assisted laser desorption/ionization-time of flight mass spectrometry,MALDI-TOF MS)鉴定临床复合群菌种及常规方法难鉴定菌种的应用价值。方法收集烟台毓璜顶医院2020年1月至2021年9月临床分离的153株非重复复合群菌种及常规方法难鉴定菌种,采用MALDI-TOF MS与16SrRNA两种方法进行菌种鉴定。结果以16SrRNA测序鉴定作为金标准,MALDI-TOF MS均可将153株复合群菌种及常规方法难鉴定菌种准确鉴定至属水平,一致性为100%。在种水平鉴定上,143株细菌MALDI-TOF MS鉴定结果与16SrRNA测序鉴定的一致性为93.5%。对于复合群菌种,MALDI-TOF MS鉴定鲍曼不动杆菌复合群、洋葱伯克霍尔德复合群的一致率均为100%,阴沟肠杆菌复合群一致率为50%(6/12),并将6株霍氏肠杆菌中的1株错误鉴定为阿氏肠杆菌,其余5株被错误鉴定成阴沟肠杆菌;对于常规方法难鉴定菌种,凝固酶阴性葡萄球菌属、其他不动杆菌属及其他不常见菌属一致率为100%,诺卡菌属一致率为89.5%,棒状杆菌属一致率为77.8%。2株Appendicis棒状杆菌和弗雷尼棒状杆菌只鉴定到属水平,2株盖尔森基兴诺卡菌鉴定成豚鼠耳炎诺卡菌。结论MALDI-TOF MS在临床复合群菌种及常规方法难鉴定菌种鉴定中具有操作简便、鉴定准确率高的优点,可用于临床微生物实验室对临床复合群菌种及常规方法难鉴定菌种标本的常规鉴定,为临床抗菌药物的使用提供依据。

Objective To explore the application value of matrix-assisted laser desorption/ionization-time of flight mass spectrometry(MALDI-TOF MS)in identifying clinical and complex group bacteria and conventional methods.Methods 153 non repetitive isolates of complex strains or strains difficult to be identified by conventional methods were collected from January 2020 to September 2021 in Yantai Yuhuangding Hospital to explore the application value of matrix-assisted laser desorption/ionization-time of flight mass spectrometry(MALDI-TOF MS)in identifying these stains.MALDI-TOF MS and 16 SrRNA sequencing were used for strain identification.Results MALDI-TOF MS can accurately identify 153 isolates of complex strains and strains difficult to be identified to the genus level,and the consistency is 100%.In species level identification,MALDI-TOF MS was consistent with 16 SrRNA in 143 isolates with a consistency of 93.5%.For complex strains the consistency rate of Acinetobacter baumannii complex and Burkholderia cepacian complex by MALDI-TOF MS was 100%,and the consistency rate of Enterobacter cloacae complex was 50%(6/12).One of the six strains of Enterobacter hormaechei was incorrectly identified as Enterobacter asburiae,and the other five strains were incorrectly identified as Enterobacter cloacae.For species difficult to be identified by conventional methods,the consistency rate was highest(100%)for coagulase-negative Staphylococcus,other Acinetobacter and other uncommon bacterial genera,followed by Norca(89.5%)and Corynebacterium(77.8%).Neither of the two Corynebacterium appendices nor Corynebacterium freneyi included in this study were accurately identified,only to the genus level,and two N.cyriacigeorgica were identified as N.otitidiscaviarium.Conclusion MALDI-TOF MS has the advantages of simple operation and high identification accuracy in the bacterial species identification,which can be used for the routine identification of specimens in the clinical microbial laboratory,providing an accurate and reliable basis for guiding the rational clinical use of antimicrobial drugs.