First-Line Anti-Tuberculosis Drug Resistance and Pattern among Smear or GeneXpert Positive Pulmonary Tuberculosis Patients in Bale Zones of Oromia Region, Southeast Ethiopia

Abstract

Background: Tuberculosis is a communicable disease that significantly contributes to global morbidity and ranks among the top causes of mortality worldwide. The problem is worsened by the emergence and spread of drug-resistant TB, especially in high-burden countries like Ethiopia. However, insufficient data on the magnitude and patterns of TB drug resistance, particularly in remote areas within these countries, hampers disease control. Therefore, this study aimed to determine the magnitude of the rate of resistance and resistance patterns to first-line anti-TB drugs among smear or GeneXpert-positive pulmonary tuberculosis patients visiting health facilities in selected districts of Bale Zones, Southeast Ethiopia.

Methods: An institution-based cross-sectional study was conducted in health facilities across eight districts of the Bale zones, including 152 smear- or GeneXpert-positive pulmonary tuberculosis patients with successful phenotypic drug susceptibility test results. Data on socio-demographics, TB treatment history, and other relevant variables were collected through a structured, pretested questionnaire. Mycobacterial drug susceptibility testing for first-line anti-TB drugs (rifampicin, isoniazid, streptomycin, and ethambutol) was performed using the indirect proportion method. Data analysis was conducted using SPSS version 20 to identify determinants of TB drug resistance.

Results: Of the 173 study participants, 152 were recruited, yielding a response rate of 88%. More than half of the participants were male (53.9%), with an age range of 5-65 years and a mean of 28.1 years (SD + 11.65). Resistance to at least one first-line anti-TB drug was 24.3% (95% CI: 17.8%, 32%). Primary and secondary resistance were 24.1% (95% CI: 17.4%, 31.9 %) and 28.6% (95% CI: 3.7%, 71 %), respectively. Rifampicin resistance was 1.3% (95% CI: 0.2%, 4.7%). Streptomycin exhibited the highest level of primary resistance (15.2%), followed by ethambutol (9%) and isoniazid (7.6%). Primary mono-resistance was greatest for streptomycin (9%) and ethambutol (4.7%). Multidrug-resistant TB was found in a single case, with resistance to all first-line agents. Resistance rates were not substantially different by sex, age, place of residence, educational status, history of previous TB treatment, history of imprisonment, history of chronic diseases, or alcohol drinking.

Conclusion: A high magnitude of primary resistance to at least one first-line anti-TB drug and primary resistance to streptomycin was observed in Bale. Although the frequency of MDR TB was relatively low, resistance to ethambutol and isoniazid was common. Expanding district-level access to drug susceptibility testing facilities and strengthening existing ones are essential for establishing an effective monitoring system for tuberculosis drug resistance. This will enable the effective combat of tuberculosis and provide evidence-based treatment in underserved, remote settings.