Identification and Clinical Correlation of Non-Tuberculous Mycobacteria isolates from Pulmonary tuberculosis suspects with HIV Co-infection at UTH,Lusaka,Zambia

Abstract

Non-tuberculosis Mycobacteria (NTM) are increasingly recognized as human pathogens especially with the emergence of Acquired Immunodeficiency Syndrome (AIDS). Similarity of clinical symptoms with TB, coupled with limited diagnostic capacities in tuberculosis (TB)- endemic areas has led to misdiagnosis of NTM pulmonary disease especially in Human Immunodeficiency Virus (HIV)-infected patients. The study aimed at assessing the spectrum of NTM species causing pulmonary symptoms in HIV-infected patients, with a secondary objective of assessing association of demographics, anaemia, body mass index (BMI), and CD4 count with NTM pulmonary disease. The study was a laboratory based cross-sectional study involving 56 NTM archival isolates from cultures of suspected pulmonary TB patients with HIV co-infection at the University Teaching Hospital (UTH), Lusaka, Zambia. Geno Type Mycobacterium CM/AS kits were used for speciation of NTM. Descriptive statistics was used to summarize data, while inferential statistics was used to evaluate associations between symptomatic NTM (dependent variable) and predictor variables. M. immunogenum was the most common NTM species (5.0%), followed by M. abscessus (3.75%), M. smegmatis (3.75%) M. gordonae (2.5%), M. fortuitum (1.25%), M. intracellulare, M. mageritense, M. celatum, and M. chelonae, all at 1.25% frequency of isolation. Organisms besides NTM species included members of the M. tuberculosis complex (MTBC) (23.75%), Gram positive bacteria with a high G+C content (43.75%) though not identified to species level. Five isolates were negative, while four could not be identified. Isolation of some pathogenic and potentially pathogenic NTM species with accompanying characteristics of clinical disease in the current study, could be suggestive of their clinical significance in HIV-infected patients in our study. The study also showed some correlations between pulmonary NTM disease and the other predictor variables (BMI, anaemia, and CD4count), though these associations were not statistically significant. The small sample size used in the study however, may not permit generalization of study findings but could form a basis for further research.