Mycobacterium Tuberculosis Resistance to Anti-tuberculosis Drugs in Coast Provincial General Hospital Mombasa, Kenya.

Abstract

Background: Kenya is one of the countries with a high TB infection rate and globally, it is ranked fifteenth amongst twenty-two countries with a high prevalence. The development of drug resistant Mycobacterium tuberculosis (MTB) strains and consequent treatment failure is a common clinical scenario in TB disease, associated with high mortality rates. However, information on drug resistance as well as both multi-drug and extensively drug resistance tuberculosis is currently very scanty in Kenya. Despite the isolated reported cases of MDR-TB in Mombasa-Kenya, detection rates are still very low, as diagnostic methods available in the public health facilities are still largely based on sputum slide smear microscopy. Therefore, the current study assessed the detection of MDR-TB and XDR-TB by molecular assay, in smear positive TB patients presenting to Coast Provincial General Hospital (CPGH), Mombasa, Kenya. Broad objective: To determine the proportion of DR-TB, MDR-TB and XDR-TB in sputa smear positive TB patients at Coast Provincial General Hospital (CPGH), Mombasa, Kenya. Materials and methods: Two hundred and fifty-six confirmed sputa smear positive TB cases diagnosed by fluorescent microscopy technique were randomly selected for molecular Gene Lipa assay for detection of mutant genes responsible for TB drug resistance to first line and second line drugs, between January and September, 2012 at the CPGH-Mombasa, irrespective of any previous TB treatment were included in the study. But prior to start of treatment for this episode, ethical approval to conduct the study was obtained from KNH/UON and CPGH ethical research committees. Questionnaire was administered to obtain both demographic and clinical data from study participants who met the inclusion criteria. Approximately 2mls of sputum was collected in a falcon-tube, decontaminated and transported to UON, molecular laboratory for mycobacteria DNA analyses using HAINS line probe assays, to detect first line drug resistance genes. This was followed by random selection of 83 cases for second line drug resistance genes. Data was analyzed for statistical correlations using SPSS statistical package version 19.0. Results: From the 256 cases in this study, male to female ratio was 1:2. The age range was 9 to 75 years, with median age of 30. The age category of 21-30 years was found to have the highest prevalence rate of PTB infection. Majority of the participants were new cases (98%), while the rest (2%) were retreatment cases. Seven of the new cases were PTB negative, constituting 4 (1.6%) PTB negative and 3(1.1%) NTM. For drug resistance detection, GenoType MTBDR® plus detected 91.7% new cases which showed full susceptibility to (INH) and (RIF). Of the remainder of the new cases, 8 (3.1%) and 1(0.4%) cases had mono- resistance to isoniazid (INH) and rifampicin (RIF), respectively. All the retreatment cases did not show drug resistance to first line drugs. Ethambutol mutation probes were included in the Hains Life sciences Genotype MTBDRsl Probe assay. For second line drug resistance testing using GenoType MTBDRsl Probe assay, 83(32%) specimens were analysed and one case each showed mono resistance to both ethambutol and fluoroquinolone (FQ). One case each was also detected for drug cross poly resistance to both (EMB) and (FQ) with second line injectable antibiotics. The proportion of cases that had HIV/AIDS -TB co-infection was 46 (17.8%), out of which 44 (17.1%) showed full susceptibility to TB drugs, while 2 (0.8%) were INH resistant. Equally no significance correlation was established between TB and the second line drugs (p=0.855). Conclusion: Conclusion: The findings of this study showed that proportion of various types of DR-TB was on the increase, and with the introduction of molecular tools such as MDRTB Lipa gene assay, at the patient’s first point of care, TB diagnosis and management could be greatly improved.