Prevalence and Drug Resistance of Mycobacterium tuberculosis Among Patients Attending DOTS Clinic in Onitsha, Anambra State

Tuberculosis (TB) caused by Mycobacterium tuberculosis remains one of the most important infectious diseases globally, with Nigeria ranked among the high-burden countries. Drug-resistant TB presents heightened challenges for case management and public health control. This study determined the prevalence and drug resistance patterns of M. tuberculosis among patients attending the Directly Observed Treatment Short-course (DOTS) clinic at St. Charles Borromeo Hospital, Onitsha, Anambra State, South East Nigeria. Sputum samples from 150 pulmonary TB suspects were processed by Ziehl-Neelsen (ZN) staining, fluorescence microscopy, and solid Lowenstein-Jensen culture. Drug susceptibility testing for first-line drugs (isoniazid, rifampicin, ethambutol, pyrazinamide, and streptomycin) was performed by the indirect proportion method and GeneXpert MTB/RIF assay for rapid detection of rifampicin resistance. Results showed a smear positivity rate of 34 percent and a culture confirmation rate of 28.7 percent. Rifampicin resistance was detected in 16 percent of culture-confirmed cases by GeneXpert. Multidrug-resistant TB (resistance to at least isoniazid and rifampicin) was confirmed in 10.7 percent of isolates. Prior TB treatment history was the strongest predictor of drug resistance. These findings confirm a substantial drug-resistant TB burden in the study area and support integration of rapid molecular diagnostics into all DOTS clinic workflows in South East Nigeria. Keywords: Mycobacterium tuberculosis, drug-resistant TB, GeneXpert, DOTS, Onitsha.