Epidemiology of clinical isolates of Mycobacterium tuberculosis at Ibadan, Nigeria.

Despite the huge burden of tuberculosis (TB) in Nigeria, case detection rate of infectious cases still remain low, thus constituting obstacle to eradication of the disease in the community. We carried out a 15 month (1st January 2008 to 30th March 2009) retrospective review of epidemiology of clinical isolates of M. tuberculosis isolated at TB regional reference laboratory at the department of Medical Microbiology and Parasitology, University College Hospital, Ibadan, Nigeria. Fifty isolates were recovered from 720 specimens during the period of study with a recovery rate of 6.9%. Sixty- two (8.6%) of the specimens were contaminated. Thirty eight (76.0%) isolates were from the specimens of male subjects and 12 (24.0%) from female subjects giving a male to female ratio of 3.2: 1.0 Majority (62.0%) of the isolates were from subjects aged 20 years and above with an isolation rate of 7.3% while only two clinical isolates (4.0%) were recovered from specimens from children. A high yield of 20.8% was recovered from specimen collected from Hausa ethnic group who predominantly domiciled in a particular part of the metropolis. In terms of socio-economic status, clinical isolates recovered from specimens from unskilled workers (76.0%) was more than thrice from that obtained from the professionals (24.0%). Seven (14.0%) of the total isolates were recovered from extra-pulmonary lesions while the majority 43 (86.0%) were for pulmonary TB. The isolation rate from children and extra-pulmonary sites are low. This suggests a need to pay more attention to diagnosis of childhood and extra-pulmonary TB in Ibadan, Nigeria.