Profiles of Isoniazid and Rifampicin drug resistance conferring mutations in Mycobacterium tuberculosis among new and previously treated pulmonary tuberculosis cases from Kisumu County, Kenya

Abstract

Mycobacterium tuberculosis infection is one of the leading causes of mortality and morbidity in developing countries and drug resistance remains a challenge. Drug resistance is hastened by point mutations in the bacilli genome and their frequencies vary geographically hence the need to understand regional specific patterns for early detection of mutant strains. In this cross sectional study, Sputum samples from pulmonary tuberculosis clinical suspects were collected to detect mutations in Mycobacterium tuberculosis that confers resistance to Isoniazid and rifampicin anti-anti tuberculosis drugs. Detection of mutations was done using GenoType MTBDRplus. Out of a sample of 256 from Tuberculosis clinical suspected cases, 145 were Mycobacterium tuberculosis bacilli confirmed out of which 32 (22%) were new Tuberculosis (TB) cases and 113(78%) retreatment. The total for isoniazid resistance was 9(6.2%), out of which 2(6.3%) were in new cases and 7(6.3%) in retreatment cases. Multi Drug Resistance (MDR) was 2(1.8%) and all in retreatment cases. Rifampicin resistance was 7(4.8%), 1 (3.1%) in new case and 6(5.3%) in retreatment. The MDR among Rifampicin Resistance(RR) was 28.6%. Low Isoniazid resilient strains had changes in the katG gene resulting to nucleotide change from A G C to A C C. Four rifampicin resistant isolates showed mutations at the rpoB gene with nucleotide change from C A C to T A C  and a single isolate displayed mutation at the rpoB gene with nucleotide change from T C G to T T G. Same nucleotide change A G C to A C C  from different patients  in the same facility might be an indication of local  transmission of drug resistance and greater variability of mutations observed in HIV positive and retreatment cases are possibilities of mutations acquired during treatment courses by repeated administration of the same anti-TB drugs.