Molecular characteristics of drug-resistance Mycobacterium tuberculosis strains isolated from extra pulmonary tuberculosis sites

Objectives: China is the second high tuberculosis (TB) burden country in the world. This article was to determinate the molecular characteristic of drug resistance Mycobacterium tuberculosis (DRTB) strains from extra pulmonary tuberculosis (EPTB).

Methods: The medical records of patients with EPTB were reviewed and collected from 2006 to 2016. The drug sensitivity of all samples was studied. All multiple drug resistance (MDR) and extensive drug resistance (XDR) strains were included. The detection of the deletion of region of difference 105 (RD105) and mycobacterial interspersed repetitive-unit variable-number tandem-repeat (MIRU-VNTR) were used to discriminate the molecular type of EPTB strains.

Results: 162 DRTB isolates were from patients with EPTB including 104 male and 58 female. Beijing genotype had a significant correlation with the patterns of DR (P<0.05), re-treatment patients (P<0.05) and gender (P<0.05). The history of treatment had a statistically significant correlation with patterns of DR (P<0.05) and gender (P<0.05). Patterns of DR had no correlation with gender (P>0.05). Of 162 strains Beijing family strains represented 91.4%. The cluster rate was 17.9% and clustering ratio was 11.1%. Beijing family genotype is predominant in the patients with EPTB. The cluster rate and clustering ratio was low.

Conclusions: Beijing family genotype is predominant and highly epidemic in the patients with drug resistance extra pulmonary tuberculosis (DR-EPTB). The cluster rate and clustering ratio was low. Genotype of re-treatment male patient with DR-EPTB is more likely Beijing family genotype.