Drug Resistance in Mycobacterium tuberculosis Isolates from Northeastern Sudan

The present study intended to determine the drug resistance patterns of Mycobacterium tuberculosis isolates among human new tuberculosis cases from northeastern Sudan using conventional and molecular techniques. Of 100 mycobacterial isolates tested by proportion method, 6% and 2% were identified, respectively, as multi drug resistant-tuberculosis (MDR-TB) and non-multi drug resistant-rifampicin (non-MDR-RIF). A total of 8% was found resistant to rifampicin (RIF), 13% to isoniazid (INH), 34% to streptomycin (STM) and 12% to ethambutol (EMB). Mono-resistant were 0% for RIF, 1% INH, 18% STM and 3% ETH. The remaining 61% isolates were identified as sensitive. Resistance to pyrazinamide was evaluated conventionally for the first time in this country and was found as low as 1%.
Molecularly, mutations of MDR-TB, RIF, INH, EMB and STM resistant isolates were detected in 66.7%, 87.5%, 76.9%, 66.7% and 17.6% of corresponding conventional findings, respectively. The genetic mutations were related to the following codons: rpoB 531 (71.4%) and rpoB 526 (28.6%) for RIF, katG 315 (90%) and mabA-inhA-15 (10%) for INH, embB 306 (66.7%) for EMB and rpsL (17.6%) for STM.
The study showed that drug resistant tuberculosis increased steadily and provided potentially valuable information on resistant genes circulating in the community. The rapid solving of this problem can benefit both public health and patient management.