RESISTANCE PATTERNS IN PATIENTS OF DRUG RESISTANT PULMONARY TUBERCULOSIS
Objective: To study the patterns of resistance to anti tuberculosis drugs in patients of drug resistant pulmonary tuberculosis.
Study Design: Cross sectional analytical study.
Place and Duration of Study: Department of Pulmonology, PEMH Rawalpindi from Jul 2016 to Dec 2017.
Methodology: Four hundred and eighty eight (n=488) adult patients with suspected pulmonary tuberculosis based on clinical history or Chest X-ray findings suggestive of pulmonary TB were included in the study after full informed consent and using consecutive sampling. Patients were evaluated with examination of sputum or/and endobronchial washings for AFB smear, MTB GeneXpert/RIF assay and Culture for mycobacterium tuberculosis with drug susceptibility testing for first and second line anti TB drugs. Patients with resistance to any anti TB drug were classified as drug resistant tuberculosis cases and pattern of drug resistance documented.
Results: Overall 74 patients were found to have drug resistant tuberculosis. Treatment naïve patients made up 48.6% of the drug resistant cases while 51.4% of the patients of drug resistant cases were previously treated cases. Among the drug resistant TB patients, 29 Patients (39.2% of the DR TB cases) were found to have MDR TB while 28 patients (37.8%) were found to have mono resistance tuberculosis. Resistance to INH was the commonest being present in 57 (77% of DR TB cases) patients which included 25 patients with mono INH resistance (89.3% of mono drug resistant cases). Fourteen patients (18.9% of DR TB) were found to have rifampicin resistance (RR-TB) on GeneXpert/RIF assay alone. Fluoroquinolone resistance was present in 22 patients (29.7% of the DR TB cases) while resistance to second line injectables was detected in three patients (4.1% of DR TB cases) including two patients diagnosed a XDR TB.
Conclusion: Drug resistant pulmonary tuberculosis was frequent in previously treated as well as new patients of pulmonary tuberculosis. Drug susceptibility testing including molecular methods for detection of resistance to first line and second line drugs are essential for optimum management of these cases.