Drug Resistance in Re-treatment Cases of Pulmonary Tuberculosis by Using the Drug Sensitivity Test

Abstract

Background: Drug resistant tuberculosis (TB), particularly multidrug resistant (MDR) represents a major global public health problem particularly in developing countries like Pakistan. Different studies have found that Drug resistant TB is associated with a higher risk of treatment failure and death. This study was done to determine the magnitude of drug resistance among retreatment cases. Objective: To determine the frequency of drug resistance in re-treatment cases of pulmonary tuberculosis by using the Drug Sensitivity Test (DST). Material and methods: Tubes containing LJ medium were separately supplemented with following drugs in each tube (Streptomycin 10 µg, Isoniazid 1 µg, Ethanbutaol 10 µg, Rifampicin 1 µg, Pyrazinamide 100 µg, Ethionamide 5 µg, Kanamycin 6 µg, Amikacin 6 µg, Ofloxacin 1 µg, Capremycin 10 µg). Any amount of growth observed in any tube with drug was considered as Resistant. If no growth observed in any of those tubes then it was Sensitive. Results: Of these 265 study cases, 157 (59.2) were male patients and 108 (40.8%) were female patients. Mean age of our study cases was 34.16 ± 8.24 years (with minimum age was 20 years while maximum age was noted to be 48 years). Mean weight of our study cases was 59.38 ± 7.54 Kg (with minimum weight was 48 Kg while maximum weight was 75 Kg). Of these 265 retreatment cases, 74 (27.9%) were of treatment failure, with relapse 53 (20%) and 138 (52.1%) were defaulters of the treatment. Drug resistance was noted in 170 (64.2%) of our study cases while 95 (35.8%) showed drug sensitivity. Conclusion: Very High frequency of drug resistance was observed among retreatment patients in our study. Failure to the compliance with treatment (defaulter of treatment) was major risk factor observed in our study. Drug resistance was significantly associated with increasing age, relapse of tuberculosis, defaulter of treatment and diabetes mellitus. More studies are required from different parts of Pakistan to generate database at National level to combat this menace. There is a need to design well directed massive awareness campaign to educate general public and to bring awareness among targeted population. Keywords: Pulmonary tuberculosis, retreatment, drug resistance.