Resistance Patterns among Multidrug-Resistant Tuberculosis Patients: A Multi-Center Study from Pakistan

Background: The high burden of multi-drug resistance tuberculosis (MDR TB) is a matter of great concern. The increasing resistance to anti tuberculosis drugs has been the area of growing concern and are posing threats to TB control. The aim of this study was to evaluate the drug resistance patterns for the first line and second line anti-Tuberculosis drugs in multiple drug resistant tuberculosis (MDR-TB) patients. Method: The study was retrospective, observational, employing purposive, non-random sampling technique for data collection conducted at the TB Clinic- of the different healthcare centers in the provinces of Pakistan Sindh and Baluchistan from December 2010 to May 2016. All bacteriologically confirmed TB patients who were found to be Rifampin Resistant (RR) on Genotypic drug susceptibility testing (GXP), or detected to be drug resistant on phenotypic Universal drug susceptibility testing were enrolled into the study. Results: Out of total 3776 patients, 96.3% were resistant to Rifampicin and 94.7% were resistant to Isoniazid. 25.5% isolates were resistant to all five first line drugs. Resistances against Pyrazinamide and Ethambutol was 54.2% and 51.6% respectively. 36.3% patients were resistant to Fluoroquinolones (FQ), 9.7% were resistant to Ethionamide (Eto) and 4.1% were resistant to both FQ and Eto. 33.5% patients were MDR plus resistant to FQ. However, the resistance to both FQ plus Aminogycosides was quite low, 2.7%. Conclusion: The drug resistance rates are quiet high in MDR-TB for both first line and second line drugs. The standardized MDR TB regimen needs to be updated, based on the prevalence of drug resistance patterns in the community for the effective management of drug resistant TB.