The impact of isoniazid resistant Mycobacterium tuberculosis on the epidemic of multi-drug resistant tuberculosis / 中华传染病杂志

ABSTRACT

Objective To investigate the impact of isoniazid (INH)-resistant Mycobacterium tuberculosis (Mtb) on the prevalence and dissemination of multi-drug resistant tuberculosis (MDR-TB).Methods A total of 251 patients diagnosed with tuberculosis in designated hospitals of Guanyun,Jiangsu and Deqing,Zhejiang from 2010 to 2011 were included in the study.The drug susceptibility tests (DST) were performed on all the Mtb isolates available from the sputum cultures.Mycobacteral interspersed repetitive units-variable number tandem repeats (MIRU-VNTR) was conducted for genotyping for all available Mtb isolates.Chi-square test,Fisher exact test,ANOVA and non-conditional Logistic regression modelling were applied for data analysis.Results Among 251 patients with Mtb isolates and DST results available,72 (28.7％) were resistant to INH,including 13 were INH mono-drug resistant.Of the remaining 59 INH-resistant Mtb,34 (13.5％) were resistant to rifampin TB and 25 were resistant to streptomycin and/or ethambutol.The clustering analysis based on MIRU-VNTR genotyping revealed 29 clustered genotypes (including 105 isolates) and 146 unique genotypes (including 119 isolates).Twentyfive clusters contained drug resistant Mtb and 16 clusters of them comprised by 37 INH-resistant isolates and 20 MDR-TB isolates,which accounted for 51.4％ of the INH-resistant isolates and 58.8％ of the MDR-TB isolates.Single factor analysis showed that sex,age,previous tuberculosis treatment history and sputum smear results were all related to INH-resistant tuberculosis and MDR-TB (all P ＜ 0.05).Multiple factors analysis showed that previous tuberculosis treatment history was risk factor of MDR-TB (OR=8.40,95 ％CI3.342-21.105),while the risk factors of INH-resistant tuberculosis were previous tuberculosis treatment history (OR=3.52,95％CI1.570-7.910),pulmonary caviry (OR=2.27,95％CI1.075-4.799) and sputum smear results (OR=0.50,95％CI0.275-0.892).Conclusions That INH-resistant strain may evolve to the MDR-TB after recent transmission is a possible trend.Patients with previous treatment history and advanced age are at high risk of INH-resistant tuberculosis and MDR-TB.