Molecular detection of rifampicin resistance by GeneXpert(®) assay among treated and untreated pulmonary tuberculosis patients from Khyber Pakhtunkhwa, Pakistan.

OBJECTIVES: Drug-resistant tuberculosis (TB) is an emerging health problem. Rifampicin (RIF) is the major first-line drug against TB. RIF resistance can be used as a marker for the detection of multidrug-resistant TB (MDR-TB). The purpose of this study was to determine the RIF resistance pattern of Mycobacterium tuberculosis complex isolates among treated and untreated patients in Khyber Pakhtunkhwa, Pakistan.

METHODS: A total of 349 drug-treated and untreated TB-diagnosed patients were enrolled in this study. RIF resistance was detected using a GeneXpert(®) assay for amplification of the RIF resistance-determining region (RRDR) region of the rpoB gene.

RESULTS: The overall prevalence of RIF resistance was 5.2% (18/349). Among 49 untreated TB patients, 3 samples (6.1%) were found resistant to RIF. Among 235 patients with a category 1 treatment regimen, 10 samples (4.3%) were resistant to RIF, whilst among 65 patients with a category 2 (Cat-2) treatment regimen, 5 samples (7.7%) were resistant to RIF. A comparison based on patient sex revealed high RIF resistance among male compared with female patients. RIF resistance was highest (4/21; 19.0%) in the 21-40 years age group among Cat-2 patients.

CONCLUSIONS: The overall prevalence of RIF resistance was high among treated and untreated TB patients. These findings will be helpful for better monitoring and management of RIF resistance in TB patients from Khyber Pakhtunkhwa, Pakistan.