DRUG RESISTANCE PATTERN AND MOLECULAR CHARACTERIZATION OF MYCOBACTERIUM TUBERCULOSIS STRAINS IN PUNJAB, PAKISTAN.

Tuberculosis (TB) is a cause of death from a single infectious agent Mycobacterium tuberculosis (MTB), leading to approximately 2.5 million deaths annually worldwide. Information regarding prevalence and pattern of drug resistance among TB patients in Pakistan remains inadequate due to the country’s limited resources. This study compared conventional diagnostic techniques with a PCRbased assay targeting IS6110 sequence. In addition, MTB drug resistant profiles against four first-line drugs (ethambutol, isoniazid, rifampin, and streptomycin) from new and retreatment cases of TB. From 101 sputum samples microscopic examination of Ziehl-Neelsen-stained smears and culturing on Lowenstein Jensen medium resulted in 96% and 100% positives, compared to 98% by PCR. Prevalence of MDR-MTB was 41.5% and 58.5% among new (n = 51) and retreatment (n = 50) cases, but 10% of the former group were sensitive to all four first-line anti-TB drugs. Thus, MDR-MTB is highly prevalent among TB patients in Punjab Province, Pakistan (where the study was conducted) and, although PCR amplification of MTB-specific IS6110 sequence was rapid, it lacked the sensitivity of the culture assay.