不同报告时间结核分枝杆菌药物敏感性试验结果不一致的原因  

The Cause Analysis of the Inconsistency in the Outcomes of Drug Susceptibility Test for Mycobacterium tuberculosis by Different Report Time

作　　者：谷蕴婷 于霞[1] 李云絮[1] 赵立平[1] 王桂荣[1] 陈素婷[1] 黄海荣[1] 

机构地区：[1]首都医科大学附属北京胸科医院北京市结核病胸部肿瘤研究所国家结核病临床实验室,101149

出　　处：《结核病与胸部肿瘤》2015年第1期1-5,共5页Tuberculosis and Thoracic Tumor

基　　金：基金项目：北京市重大科技攻关项目（D121100003012001）

摘　　要：目的探讨和分析使用绝对浓度法药物敏感性试验（简称“药敏试验”）时不同报告时间结果不一致的原因。方法2010年1—6月笔者收集采用绝对浓度法于37℃含INH的L-J培养基上培养4周时无菌落生长、时间延长至6周后才生长的13株菌株（含药培养基延迟生长菌株）。这些菌株来源于11例结核病患者（2例患者的菌株在低浓度和高浓度INH时均有菌落生长）；同时收集这11例结核病患者的临床敏感株作为对照菌株，共计24株菌株。进行比例法药敏试验和PCR菌种鉴定，并利用分枝杆菌散在分布重复单位（Mycobacterium interspersed repetitiveunit,MIRU）和结核分枝杆菌间隔区寡核苷酸分型（spoligotyping）技术进行基因分型，并选择对照菌株和含药培养基延迟生长菌株MRIU分型不同的3株菌株进行人工模拟不同浓度INH时混合的敏感菌株和耐药菌株进行绝对浓度法药敏试验，观察不同报告时间（4周和6周）的药敏试验结果。结果24株菌株经PCR鉴定均为结核分枝杆菌复合群。比例法药敏试验中13株含药培养基延迟生长菌株均对INH耐药，11株对照菌株均对INH敏感。3例患者的对照菌株和含药培养基延迟生长菌株Spoligotyping分型属于不同型别，分别为北京基因型和T2型、北京基因型和H3型、北京基因型和T2型。人工混合感染的3株菌株比例（临床株：H37Rv）小于1：128时可能会出现4周无菌落生长而6周有菌落生长的结果。结论对药物敏感性不同的结核分枝杆菌造成的混合感染，当耐药菌株的比例较低时，可能造成不同报告时间药敏试验结果不一致的情况。Objectives To determine when the susceptibility of the colony forming on the slants performed by absolute concentration method the cause analysis of the inconsistency in the outcomes of drug susceptibility test for Mycobacterium tuberculosis by different report time. Methods Thirteen isolates on the INH containing medium from 11 patients with colony forming after six weeks were collected and the strains on the drug free L-J medium were also collected. All 24 collected strains were performed PCR species identification, MIRU and spoligotyping gene typing, drug susceptibility tests （DST）, INH resistant gene and randomly selected 3 strains （7019H0.2, 7285H0.2 and 7325H1） to do DST for Simulation mixed population of INH susceptible and resistant strains. Observe the results in differert report time （4 and 6 weeks）. All the patients were received telephone follow-up about treatment and drug resistance results. Results All 13 isolates from INH contain medium were INH resistant when the proportion method was performed after subculture while all ll strains from drug free medium were all INH susceptible. All the 13 isolates from INH containing medium and 11 isolates from control medium were identified as Mycobacterium tuberculosis complex （MtbC）. of 13 isolates from INH resistant strains, l0 strains （10/13, 76.92%） had mutation in the katG gene （S315T）. Among the ll patients, 3 patients were proved to be INH resistant in the following DST. Three patients owned the different genotype between the drug containing medium and control medium. The genetype were Beijing and T2, Beijing and H3, Beijing and T2. Three strains mixed with H37Rv grown after 6 weeks instead of 4 weeks when the proportion was less than l： 128 （clinical isolate： H37Rv）. Conclusion Case of mixed infection of different drug sensitivity caused by Mycobacterium tuberculosis, when the proportion of resistant strains is low, it may cause inconsistent results in different report time.

关 键 词：分枝杆菌 结核 微生物敏感性试验 偏差 

分 类 号：R378.911[医药卫生—病原生物学]