Isoniazid resistance among rifampicin-susceptible Mycobacterium tuberculosis isolates from tuberculosis patients.

INH resistance among RIF-susceptible isolates was present in 10-15% of the total cases. Among these cases, the use of RIF susceptibility alone will fail to detect INH resistance. Since higher rates of failure, relapse, or acquired resistance are linked with INH resistance, rollout of techniques focusing on RIF resistance must, therefore, be accompanied by strict monitoring for better management of patients.