Drug Susceptibility Patterns of Mycobacterium tuberculosis Isolates from Tuberculosis Patients in Coastal Kenya

Abstract

Background: Tuberculosis (TB) is an infectious disease caused by the bacillus Mycobacterium tuberculosis. Anti-tuberculosis drug resistance is an emerging health problem in Kenya and especially in Coastal region. This is a major challenge in tuberculosis control. Diagnosis is based on Ziel-Neelsen staining alone and patients are treated without information on sensitivity patterns. Aim: This study aimed to determine drug susceptibility patterns of Mycobacterium tuberculosis in Coastal Kenya. Study Design: Hospital and laboratory based cross-sectional study was carried between April 2015 and July 2016 at Coast General Referral hospital; Tudor, Port-Reitz, Likoni Sub-County hospitals; Mlaleo, Kongowea and Mikindani health centers. Methodology: Sputum samples from patients with bacteriological confirmed TB on microscopy were cultured on Lowenstein Jensen (LJ) media. Strains of MTB complex from Lowenstein Jensen (LJ) slopes were subjected to drug susceptibility testing (DST) to first-line drugs including isoniazid (H), rifampicin (R), streptomycin (S) and Ethambutol (E) using proportional method on the Mycobacterium Growth Indicator Tube (MGIT) conventional method. Participants were offered diagnostic testing and counselling for HIV testing. Results: Drug sensitivity test was performed for a total of 210 Mycobacterium tuberculosis isolates for the first line anti-TB drugs. About seventy eight percent and twenty nine percent of the strains from new patients and previously treated patients were fully sensitive to all the drugs tested respectively. Prevalence of any resistance to one drug was 102 (48.6%, 95% CI: 20.45 - 28.23). Any single drug resistance was most frequent in isoniazid 30 (16.0%), Ethambutol 20 (10.0%), Streptomycin 18 (18.3%) and Rifampicin 4 (2.1%) in newly diagnosed patients. Among previously treated patients any resistance to streptomycin, ethambutol, isoniaziad and rifampicin was 10 (58.8%), 9 (52.9%), 7 (41.2%) and 4 (23.5%) respectively. Prevalence of MDR-TB defined as resistant to at least both isoniazid and rifampicin was 10 (4.8%) among new and previously treated patients respectively. Conclusion: The current study reveals that the overall resistance to first line anti-TB drugs was high. Although the rate of MDR-TB was relatively low, this signifies that conditions favouring the spread of MDR-TB are on high rise. Therefore, it is essential to address the problems of development of drug re-sistant strains of TB by establishing good TB programmes (DOTS). Patients’ adherence to anti-TB drugs and introducing drug sensitivity testing (DST) services at County level hospitals will minimize occurrence of drug resistant.