Attenuated tuberculin skin test responses associated with Mycobacterium intracellulare sputum colonization in an adolescent TB prevalence survey in Western Kenya

Lilian N Njagi; Grace Kaguthi; Jared O Mecha; Thomas R Hawn; Videlis Nduba

doi:10.1016/j.tube.2024.102514

Attenuated tuberculin skin test responses associated with Mycobacterium intracellulare sputum colonization in an adolescent TB prevalence survey in Western Kenya

Tuberculosis (Edinb). 2024 May 5:147:102514. doi: 10.1016/j.tube.2024.102514. Online ahead of print.

Authors

Lilian N Njagi¹, Grace Kaguthi², Jared O Mecha³, Thomas R Hawn⁴, Videlis Nduba⁵

Affiliations

¹ Kenya Medical Research Institute, Centre for Respiratory Diseases Research (CRDR), PO Box 47855-00100, Nairobi, Kenya. Electronic address: njagi.lilian@gmail.com.
² Kenya Medical Research Institute, Centre for Respiratory Diseases Research (CRDR), PO Box 47855-00100, Nairobi, Kenya. Electronic address: skiringa@gmail.com.
³ Department of Clinical Medicine and Therapeutics, Faculty of Health Sciences, University of Nairobi School of Medicine, PO Box 19676 - 00202, Nairobi, Kenya. Electronic address: jomecha@gmail.com.
⁴ Department of Medicine, University of Washington, Seattle, WA, 98195, United States. Electronic address: thawn@uw.edu.
⁵ Kenya Medical Research Institute, Centre for Respiratory Diseases Research (CRDR), PO Box 47855-00100, Nairobi, Kenya. Electronic address: vnduba@gmail.com.

PMID: 38723342
DOI: 10.1016/j.tube.2024.102514

Abstract

Introduction: Exposure to Non-tuberculous Mycobacteria (NTM) varies regionally and may partly explain the disparate outcomes of BCG vaccination and tuberculosis (TB) susceptibility.

Methods: We examined NTM sputum colonization, associations with clinical characteristics, and tuberculin skin test (TST) responses in an adolescent TB prevalence survey.

Results: Among 5004 adolescents screened, 2281 (45.5 %) were evaluated further. TB and NTM prevalence rates were 0.3 % and 8.0 %, respectively. Among 418 NTM isolates, 103 were unidentifiable, and 315 (75 %) comprised 15 species, the most frequent being M. intracellulare (MAC) (108, 26 %), M. scrofulaceum (96, 23 %) and M. fortuitum (51, 12 %). "NTM colonized" adolescents had less frequent chronic cough and night sweats (adjusted odds ratio [aOR] 0.62, 95 % confidence interval [CI] 0.44-0.87and aOR 0.61, CI 0.42-0.89 respectively), and lower TST induration (median 11 mm (interquartile range [IQR] 0-16) vs 13 mm (IQR 6-17; p = 0.006)) when compared to "NTM not colonized" participants. MAC, but not M. scrofulaceum or M. fortuitum, was associated with decreased TST induration (median 7.5 mm (IQR 0-15) vs 13 mm (IQR 6-17) among "MAC colonized" vs "not colonized", p = 0.001).

Conclusion: We observed high NTM prevalence rates with species-specific associations with TST induration, consistent with a model of species-dependent heterologous immunity among mycobacteria.

Keywords: Adolescents; Heterologous immunity; NTM; TB vaccines; TST; Tuberculosis.

Grants and funding

D43 TW011817/TW/FIC NIH HHS/United States