SMIS检测分枝菌酸在分枝杆菌菌种鉴定中的作用

Evaluation of mycolic acid analysis in identification of Mycobacterium species through SMIS

目的 评估用SMIS检测分枝菌酸在分枝杆菌菌种鉴定中的作用。方法 收集北京市结核病胸部肿瘤研究所2007年1—12月的分枝杆菌118株，通过PNB培养基初筛，其中结核分枝杆菌复合群25株，非结核分枝杆菌93株。同时用测序方法和SMIS分析分枝菌酸方法鉴定118株分枝杆菌，以16SrDNA和16—23SrDNAITS测定作为菌种鉴定的标准，评估利用SMIS分离分枝菌酸鉴定分枝杆菌菌种的符合率及一致性；并验证以上两种方法鉴定结果分别与PNB初筛分结核分枝杆菌复合群和非结核分枝杆菌结果的符合率及一致性。结果 SMIS与测序鉴定分枝杆菌相比的符合率为92％（108／118），其中结核分枝杆菌复合群鉴定的符合率为95％（35／37），非结核分枝杆菌为90％（73／81），Kappa分析显示两种方法鉴定结果的一致性很好（Kappa=0．96）。回顾验证初筛结果显示，SMIS与PNB培养基方法鉴定结果符合率90％（106／118），一致性较好（Kappa=0．73）；测序方法与PNB培养基方法鉴定结果符合率也为90％（106／118），一致性较好（Kappa=0．74），但有11株测序和分枝菌酸菌种鉴定方法结果相同的结核分枝杆菌复合群与PNB实验结果不一致。结论 利用分枝菌酸对临床分离的分枝杆菌进行菌种鉴定是一种快速、简便和准确的方法，对处置应急和突发公共卫生事件中的分枝杆菌菌种鉴定具有一定的参考价值，是分枝杆菌菌种多相鉴定策略的重要组成部分。

Objective To evaluate the usefulness of mycolic acid for identification of Mycobacterium species using SMIS. Methods One hundred and eighteen clinical Mycobacterium isolates collected from Beijing Tuberculosis and Thoracic Tumor Research Institute through whole year of 2007 were analyzed. The 118 isolates contain 25 isolates of Mycobacterium tuberculosis and 93 non tuberculosis Mycobacterium identified by PNB method. Myeolic acid analysis using SMIS is evaluated for identification of a broad range of Mycobacteria in comparison with 16S rDNA , 16-23S rDNA ITS sequencing to measure the concordance rate and agreement, and verify the concordance rate and agreement among results of mycolic acid, sequencing and PNB in identifying Mycobacterium tuberculosis and non tuberculosis Mycobacterium. Results The concordance rate between mycolic acid method analysis and DNA sequencing is 92% （ 108/118 ）, of which concordance rate in Mycobacterium tuberculosis complex and non tuberculosis Mycobacterium are 95% （35/ 37） and 90% （73/81） respectively, agreement of both is great（ agreement Kappa value is 0. 96）. Through retrospective analysis, the concordance of resuhs between SMIS and PNB method analysis is 90% （106/118） and agreement is well（ agreement Kappa value is 0. 73 ） , the concordance of results between sequencing and PNB method analysis is also 90% （106/118） and agreement is well（ agreement Kappa value is 0. 74）, despite the identification results of 11 isolates by PNB method are discordant. Conclusion Mycolic acid analysis by SMIS enables rapid identification of a broad range of clinical Mycobacterium species, which could play an important role in polyphasic identification of Mycobacterium species.