Drug resistant strains of Mycobacterium tuberculosis identified through PCR-RFLP from patients of Central Punjab, Pakistan.

The study was carried out to determine, by PCR-RFLP, the magnitude of drug resistance in Mycobacterium tuberculosis The study was carried out on 221 random sputum samples collected from patients and 120 suspected cases of drug resistance. Genetic variation in drug-resistant strains was evaluated through PCR-RFLP for isoniazid, ethambutol, streptomycin, and ofloxacin. Out of 341 patients, 91.5% were confirmed as M. tuberculosis complex infected on the basis of PCR. The random samples revealed resistance in 8.2% cases, while 73.3% of those with suspected drug resistance were found resistant. Among drug-resistant isolates, 56.1% were resistant to a single drug, 33.3% to two drugs, and 10.6% to more than two drugs. Ofloxacin resistance was observed along with isoniazid, ethambutol, and streptomycin in 6.5% cases. Resistance to isoniazid was observed in 61% cases, to ethambutol in 50.4%, and to streptomycin in 43.1% cases. It was concluded that PCR-RFLP is a useful molecular technique for the rapid detection of mutations in drug-resistant tuberculosis patients and may be used to diagnose drug resistance at the earliest.