Genotyping and Drug Resistance Patterns of M. tuberculosis in Eastern Amhara region, Ethiopia

Background: Ethiopia is among the countries with the highest incidence of tuberculosis (TB) and has a early incidence of 379 cases/100,000 population. Of the high TB burden regions, Amhara is the top. So understanding the epidemiology of TB through molecular genotyping techniques such as Spoligotyping have invaluable role to combat TB. It will help to designing appropriate intervention and strengthen TB control program. Objectives: To provide insight about the genetic biodiversity of Mycobacterium tuberculosis, strain specific drug susceptibility and possible associated factors in Eastern Amhara region, Ethiopia. Methods: A facility based cross sectional study was conducted among smear positive TB patients (age ≥ 18 years old) from September 2011 to June 2012. Smear positive sputum samples were processed and decontaminated by the modified Petrof method. Primary isolation and drug susceptibility testing (DST) were carried out on egg based Lowenstein-Jensen (LJ). Genotyping of mycobacterial DNA was performed by spoligotyping and isolates were assigned to families using the SpolDB4 and the model-based program ‘Spotclust’. P-values less than 0.05 were considered as statistically significant. Result: The predominant Mycobacterium tuberculosis strains in the present study were ST 149/T3-ETH 49(22.6%), ST53/T1 18(8.3%) and ST50/H3 16(7.4%). T3-ETH strain showed the highest MDR-TB cases. Conclusion: Our finding suggests that a diversity of Mycobacterium tuberculosis strains accompanied with high rate of drug resistance.