Mycobacterial adenitis: role of Mycobacterium bovis, non-tuberculous mycobacteria, HIV infection, and risk factors in Arusha, Tanzania.

OBJECTIVE

To assess risk factors and mycobacterial agents in mycobacterial adenitis.

DESIGN

Cross sectional involving comparison analysis of high-risk groups.

SETTING

Seven hospitals in rural and semi-rural districts of Arusha.

SUBJECTS: The study comprised of 457 patients of clinically diagnosed mycobacterial adenitis.

INTERVENTIONS: Biopsy materials were cultured and identification of mycobacterial isolates, and HIV infection testing were performed using standard methods. A questionnaire was used to establish information for assessing risk factors.

MAIN OUTCOME MEASURES: Proportions of mycobacterial isolates, risk factors and odds ratios.

RESULTS

Of the 457 specimens, 65(14.2%) were culture positive. Isolates identified were M. bovis, 7(10.8%) M. tuberculosis, 27(41.5%) and non-tuberculous mycobacteria 31(47.7%). HIV infection and ingestion of raw milk were linked with increased risk of M. bovis infection by OR of 13.6 (95% CI, 1.7 - 109.9) and 15.28 (3.26 - 71.7), respectively. On multivariate analysis, an OR of 16.2 (1.3 - 201.3) for having M. bovis adenitis was linked to HIV infection, raw milk and houses with poor ventilation. An OR of 5.2 (1.2 - 20.6) for non-tuberculous mycobacterial adenitis was linked to history of TB in the family, HIV infection, raw milk, raw animal products and poor knowledge on transmission of tuberculosis.

CONCLUSIONS

M. bovis caused one out of ten cases of culture positive mycobacterial adenitis. Non-tuberculous mycobacteria were more common than M. tuberculosis (50% and 40% of the cases, respectively). HIV infection and raw animal products are among the risk factors identified for M. bovis and non-tuberculous mycobacterial adenitis.