Antibiotic sensitivity of Mycobacterium tuberculosis isolates; a retrospective study from a Saudi tertiary hospital

OBJECTIVES: This study aims to examine the antibiotic sensitivity of Mycobacterium tuberculosis isolates and its drug resistance. We also evaluated the relationship between demographic characteristics and tuberculosis (TB) drug susceptibilities. METHODS: A retrospective study was conducted to analyse the antibiotic sensitivity of M. tuberculosis isolates and its resistance to first-line anti-TB drugs. During the period 2008–2013, the medical records of 191 patients from the TB ward and the Out-Patient Department in an Eastern KSA tertiary hospital were reviewed. RESULTS: We classified the specimens into two categories: extra-pulmonary and pulmonary TB. Among the extra-pulmonary TB specimens, 36.5% were from body fluids, 29.2% from tissue cultures and 5.2% from body abscesses. In case of pulmonary TB, sputum samples accounted for the highest proportion of the specimens (28.6%), followed by bronchial aspirates and pleural fluid (13.2% and 5.7%, respectively). Clinical isolates from women showed higher resistance to ethambutol compared to those from men. Isoniazid showed the highest resistance pattern among all antibiotics tested (17%). Meanwhile, tissue cultures had higher resistance to Isoniazid antibiotic compared to the other specimens. CONCLUSION: Resistance to first-line TB drugs is higher in extra-pulmonary TB isolates than pulmonary isolates. Nearly one-fourth of all M. tuberculosis clinical strains were resistant to the antibiotics tested in mono-resistant or multi-resistant manners. Women had greater resistance to TB drug ethambutol as compared to men. Meanwhile, extra-pulmonary TB specimens, specifically that from tissue cultures, showed greater resistance to Isoniazid than other clinical specimens.