Discrepancies in Drug Susceptibility Test for Tuberculosis Patients Resulted from the Mixed Infection and the Testing System

作者：Mei, Zaoxian; Sun, Zhaogang; Bai, Dapeng; Xu, Yuhui; Li, Zhiling; Huang, Hairong; Li, Chuanyou; Xu, Shaofa^*; Li, Li

来源：Biomed Research International, 2015, 2015: 651980.

DOI：10.1155/2015/651980

• RESISTANT MYCOBACTERIUM-TUBERCULOSIS
• BACTEC 460 SYSTEM
• LIQUID CULTURE
• MB/BACT SYSTEM
• STRAINS
• ASSOCIATION
• PROPORTION
• MUTATIONS
• DIAGNOSIS
• RIFAMPIN

To find the potential reasons for the discrepancies in the drug susceptibility test (DST) of M. tuberculosis isolates, twenty paired isolates with disputed drug susceptibilities to isoniazid (INH) were selected according to the MGIT960 testing and Lowenstein-Jensen (L-J) proportion methods. Their MICs were confirmed again by broth microdilution method and by L-J proportion method. The spoligotyping results showed that, of all the 20 paired strains, 11 paired isolates belonged to the Beijing genotype and 6 paired isolates belonged to SIT1634, and that each of the remaining 3 paired isolates had two genotypes, namely, SIT1 and SIT1634. Those 3 paired isolates with different intrapair spoligotypes were further confirmed as mixed infection by the results that those three pairs of isolates with different 12 locus MIRU intrapair types and one pair carried different base pair at codon 315 (AGC versus AAC). Totally mutations in the katG gene were identified in 13 paired isolates. No mutations were found in the regulatory sequences and open reading frames (ORF) of the inhA and ahpC genes in any of the tested isolates. Those results showed that the different test systems and the mixed infection with particular genotypes of M. tuberculosis strains contributed to the drug susceptibility discrepancies.

• 出版日期2015
• 单位天津市海河医院; 北京市结核病胸部肿瘤研究所; 首都医科大学; 北京老年医院