Prevalence and Risk Factors for Pulmonary Mycobacteriosis in Lagos, Nigeria

Abstract

Background: Pulmonary mycobacteriosis has been documented in HIV-infected, diabetics, asthmatics, smokers and alcoholics and its progression and severity are affected by these risk factors. Inappropriate diagnosis of mycobacteriosis could lead to inappropriate treatment with anti- tuberculosis drugs. Methods: This cross-sectional, prospective study was conducted in patients with TB-like diseases attending six DOTs centres in Lagos, Nigeria, from May 2012 to October 2016. Participants’ informed consent was obtained, structured questionnaires administered to obtain socio-demographic and co-morbid data. Sputum samples collected and processed for microscopy and culture using Lowenstein-Jensen medium with or without pyruvate and MGIT 960 liquid medium. Mycobacteria were identified using MPT64 immunochromatographic, biochemical and molecular methods. This study investigated the presence and prevalence of mycobacteriosis in the participants and assessed the risk factors for the mycobacterial infections. Results: Of the 1,020 participants, 339 (33.2%) had mycobacteriosis of which 33 (9.7%) were caused by Non-Tuberculosis Mycobacteria (NTM) and 306 (90.3%) caused by Mycobacterium tuberculosis complex (MTBC). Of the isolated 306 MTBC, 247 (80.7%) were M. tuberculosis, 28 (9.2%) were M. africanum, 23 (7.5%) were M. bovis while 8(2.6%) were M. ulcerans [P < 0.0005]. The 33 NTM showed 11 (33.3%), 20 (60.6%) had HIV, 8(24.2%) M. fortuitum, 2 (6.1%) M. abscessus, 2 (6.1%) M. scrofulacium, 6 (18.2%) M. kansasii, 4 (12.1%) M. megateriense and 11 (33.3%) Mycobacterium avium complex (MAC). Sequence analysis of the 16s rRNA of the 11 MAC showed 3 (27.3%) M. avium, 5(45.5%) M. intracellulare, 2(18.2%) M. colombiense and 1(9.1%) M. velneri.  M. fortuitum and MAC were significantly (P<0.05) associated with HIV infection, while only M. fortuitum relate strongly with diabetes (P <0.05). Conclusion: The study showed that mycobacteriosis is caused by different species of MTBC and NTM. Relatively high mycobacteriosis were detected during dry season and were significantly associated with gender, age, HIV and diabetes.