Prevalence of non-tuberculous mycobacteria among previously treated TB patients in the Gulf of Guinea, Africa

B D Thumamo Pokam; D Yeboah-Manu; S Ofori; P W Guemdjom; P M Teyim; L Lawson; D Amiteye; N Y Yhiler; I C Djuikoue; A E Asuquo

doi:10.1016/j.ijregi.2022.05.003

Prevalence of non-tuberculous mycobacteria among previously treated TB patients in the Gulf of Guinea, Africa

IJID Reg. 2022 May 14:3:287-292. doi: 10.1016/j.ijregi.2022.05.003. eCollection 2022 Jun.

Authors

B D Thumamo Pokam^{1

2}, D Yeboah-Manu², S Ofori², P W Guemdjom³, P M Teyim⁴, L Lawson⁵, D Amiteye⁶, N Y Yhiler^{1

7}, I C Djuikoue^{8

9}, A E Asuquo¹⁰

Affiliations

¹ Department of Medical Laboratory Science, University of Buea, Buea, Cameroon.
² Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana.
³ Department of Public Health, University of Buea, Buea, Cameroon.
⁴ Douala Tuberculosis Reference Laboratory, Littoral Region, Cameroon.
⁵ Zankli Medical Centre, Utako, Abuja, Nigeria.
⁶ Department of Biomedical Engineering, All Nations University College, Koforidua, Ghana.
⁷ Department of Allied Health, Biaka University Institute, Buea, Cameroon.
⁸ Microbiology Department, Faculty of Health Sciences, Université des Montagnes, Bangangte, Cameroon.
⁹ Foundation Prevention and Control, Cameroon.
¹⁰ Department of Medical Laboratory Science, College of Medicine, University of Calabar, Calabar, Nigeria.

Abstract

Objective: Differentiation between non-tuberculous mycobacteria (NTM) and Mycobacterium tuberculosis complex (MTBC) is crucial for case management with the appropriate antimycobacterials. This study was undertaken in three West and Central African countries to understand NTM associated with pulmonary tuberculosis in the sub-region.

Methods: A collection of 503 isolates (158 from Cameroon, 202 from Nigeria and 143 from Ghana) obtained from solid and liquid cultures were analysed. The isolates were tested for drug susceptibility, and MTBC were confirmed using IS6110. All IS6110-negative isolates were identified by 65-kilodalton heat shock protein (hsp65) gene amplification, DNA sequencing and BLAST analysis.

Results: Overall, the prevalence of NTM was 16/503 (3.2%), distributed as 2/202 (1%) in Nigeria, 2/158 (1.3%) in Cameroon and 12/143 (8.4%) in Ghana. The main NTM isolates included 5/16 (31.3%) M. fortuitum, 2/16 (12.5%) M. intracellulare and 2/16 (12.5%) M. engbaekii. Eight (57.1%) of the 14 previously treated patients harboured NTM (odds ratio 0.21, 95% confidence interval 0.06-0.77; P=0.021). Three multi-drug-resistant strains were identified: M. engbaekii, M. fortuitum and M. intracellulare.

Conclusion: NTM were mainly found among individuals with unsuccessful treatment. This highlights the need for mycobacterial species differentiation using rapid molecular tools for appropriate case management, as most are resistant to routine first-line antimycobacterials.

Keywords: Drug resistance; NTM; Retreatment patients; West/Central Africa; hsp65 sequencing.