Characterization of Mycobacterium Tuberculosis (MTB)-Positive Individuals within the Healthcare Catchment Area of Mzuzu Central Hospital, Malawi

Abstract

Purpose
To investigate the characteristics of the Mycobacterium tuberculosis (MTB)-positive population within the healthcare service area of Mzuzu Central Hospital in Malawi, with the objective of providing a scientific foundation for tuberculosis (TB) prevention and control strategies in the region.
Methods
This retrospective study encompassed 4,711 patients who underwent GeneXpert (GeneXpert MTB/RIF or GeneXpert MTB/RIF Ultra) testing. Data on laboratory results, demographics, HIV status, and residential addresses were analyzed.
Results
Among 4,711 patients, 424 (9%) tested MTB-positive. A strong correlation was observed between MTB and HIV infection, as HIV/TB co-infection accounted for 47.9% of MTB-positive cases (χ²=46.311, p<0.001). The MTB positivity rate for males, at 12.4% (291/2341), is significantly higher ( χ²=66.858, p<0.001) than that for females, which stands at 5.6% (133/2370), irrespective of HIV status. The age distribution of MTB-positive patients peaked in the 21-55 age bracket, with a median age of 37.0 (29.0, 47.0). The third quarter of each year, particularly September exhibited the highest positivity rate of 13.1%. Within Mzimba District, 87.8% of TB patients resided in Mzuzu city, with Luwinga (21.8%), Mchengautuwa (12.5%), and Zolozolo (9.9%) being the top three townships. Most newly diagnosed cases received treatment (85.1%), but the rifampicin resistance rate (4.7%) exceeded the national average.
Conclusion
Within the healthcare catchment area of Mzuzu Central Hospital, MTB infection is significantly associated with HIV. Males show a higher MTB positivity rate than females. The study identifies high-risk age groups, temporal trends, and geographical TB patterns. Rifampicin resistance is a critical issue needing urgent attention.