Studies on the Co-Infectivity Of HIV and Atypical Mycobacteria In Nsukka Local Government Area Of Enugu State

Abstract

The increasing global incidence of tuberculosis and nontuberculous mycobacteria (NTM) has been attributed to immunosuppresion due to the Human immunodeficiency virus (HIV) epidemic. The paucity of information on the contribution of NTM to mycobacterial infections in Africa including Nigeria has however been closely associated with limited laboratory culture for its isolation and identification. This study investigated the co-infectivity of HIV and Atypical Mycobacteria in Nsukka L.G.A. Two hundred cases (100 HIV negative: 56 males and 44 females and 100 HIV positive- 39 males and 61 females), between the ages of 15 and 71 years with mean age of 37.5 years participated in the research. HIV antibodies were screened using two HIV test kits: the Determine (Abbot Co Ltd, Japan) for preliminary test and the Gold (Unigold) which was used to check for consistency. CD4+ count was carried out using the cytometry (CyFlow®), while acid fast bacilli (AFB) were identified by the Ziehl-Neelson staining technique. AFB positive samples were subjected to nested PCR for species identification. T-test was employed to check for statistical significance between the mean prevalence in test and control groups and CD4 count of HIV single infection and co infection with TB. Chi square correlation was also employed to check for relationship between the demographic characteristics and the distribution of the disease. A preponderance of HIV infection was observed among the age group 21-50 years (72.5%) with overall HIV prevalence of 19.4%. The highest AFB prevalence of 26.6% was observed among patients aged 21-30 years, with overall prevalence of 24%. About 79.1% of TB infection occurred at CD4 count less than 400 cells/µl. Molecular analysis of the samples (using nested PCR) showed 97 (78.9%) M. tuberculosis, 14 (11.4%) M. bovis and 10 (8.1%) NTM. The NTM identified was M. avium complex (MAC). The prevalence rate of TB/HIV co-infection was 24 (24%) out of which 14 (53.8%) were M. tuberculosis, 5 (20.8%) were M. bovis and 3 (12.5%) were NTM. The highest NTM prevalence of 66.7% was observed among patients aged 21-30 years in the HIV positive group while the highest prevalence of 42.8% was observed among 41-50 years in the HIV negative group. TB co-infection was significantly associated with CD4+ cell count (P <0.05). Individuals with lower level of education and the rural settlers were observed to be at higher risk of TB co-infection with HIV (RR =1.40, P =0.002) and (RR = 3.17, P = 0.01). This study establishes the significant role of non-tuberculous AFB organisms in pulmonary TB and HIV co-infection and subsequently enhanced progression to the active disease, AIDS. Furthermore, it underscores the importance of introduction of molecular screening assays for the rapid and efficient detection of NTM infections in high burden, and resource limited settings such as Nigeria for effective management and control of HIV/TB co-infectivity.