GenoType MTBDRplus assay for rapid detection of rifampin and isoniazid resistance in Mycobacterium tuberculosis in Sichuan

Objective To explore the molecular and epidemic characteristics of rifampin(RFP) and isoniazid(INH) resistance of mycobacterium tuberculosis(MTB) in Sichuan.Methods GenoType ? MTBDRplus Assay GTplus was used to examine 68 clinical isolates of MTB and 105 clinical specimens for mutations in rpoB,katG and inhA genes related to RFP and INH resistance.Results Of the 151 valid tests obtained,44(29.14%) and 26(17.22%) showed drug resistance and multidrug resistance,respectively.Resistance to RFP and INH was found in 21.85%(33/151) and 24.50%(37/151) of the samples,respectively.The most prevalent mutations were rpoB S531L,katG S315T1 and inhA C-15T.The multidrug resistance rate in the sputum specimens was significantly higher than that in the non-respiratory samples(19.35% vs 7.41%) .Conclusion Drug-resistant,especially multidrug-resistant tuberculosis is highly prevalent in Sichuan.The multidrug-resistant bacteria most frequently show rpoB S531L combined with katG S315T1 mutations,suggesting the necessity of developing rapid clinical identification methods for drug-resistant MTB to control the spread of the resistant strains.