Characterisation of Drug-Resistant Strains of Mycobacterium tuberculosis Isolated from TB and HIV Co-Infected Patients Attending Chest Clinic at Kericho County Referral Hospital, Kenya DOI: https://dx.doi.org/10.4314/ajhs.v38i3.4

Abstract

Background: Tuberculosis-HIV (TB-HIV) co-infection remains a leading cause of AIDS-related mortality. HIV-induced immunosuppression increases TB susceptibility and risk of treatment failure when drug-resistant strains occur, making MDR-TB surveillance critical. This study aimed to characterise multidrug-resistant Mycobacterium tuberculosis (MDR-TB) strains among TB-HIV co-infected patients at the Chest Clinic of Kericho County Referral Hospital, Kenya.

Methods: A hospital-based cross-sectional study was conducted among patients receiving highly active antiretroviral therapy (HAART) at the Chest Clinic of Kericho County Referral Hospital between February and September 2024. A total of 174 sputum samples were collected from TB-HIV co-infected patients. Phenotypic and genotypic assays were used to characterise MDR-TB strains and assess their genetic diversity. Statistical analysis was performed using STATA version 18, incorporating inferential tests to evaluate diagnostic agreement and linear regression to identify predictors of drug resistance mutations.

Results: Of the 174 screened patients, 156 were enrolled, comprising 113 females (72.4%) and 43 males (27.6%). Among the HIV-infected patients, Mycobacterium tuberculosis was the predominant species (80.6%, n = 88), while non-tuberculous mycobacteria accounted for 19.4% (n = 25) of isolates. Of the 95 MTB isolates, 19 (20%) exhibited resistance to at least one first-line drug: five (5.3%) to isoniazid, six (6.3%) to rifampicin, and eight isolates were classified as MDR-TB (resistant to both INH and RIF). Resistance-associated mutations were detected in katG and inhA (INH resistance) and rpoB (RIF resistance). Lineage 4 (71.3%) was the most prevalent, followed by Lineage 3 (23.8%).

Conclusion: High female enrollment may reflect gender differences in healthcare access or disease burden. The 20% resistance rate among MTB isolates, including 8.4% MDR-TB with well-characterised mutations, is concerning. Findings highlight the need for enhanced drug susceptibility testing and tailored strategies in high-burden settings.