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Peters JS, McIvor A, Papadopoulos AO, Masangana T, Gordhan BG, Waja Z, Otwombe K, Letutu M, Kamariza M, Sterling TR, Bertozzi CR, Martinson NA, Kana BD. Differentially culturable tubercle bacteria as a measure of tuberculosis treatment response. Front Cell Infect Microbiol 2023; 12:1064148. [PMID: 36710965 PMCID: PMC9877613 DOI: 10.3389/fcimb.2022.1064148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 12/22/2022] [Indexed: 01/13/2023] Open
Abstract
Introduction Routine efficacy assessments of new tuberculosis (TB) treatments include quantitative solid culture or routine liquid culture, which likely miss quantification of drug tolerant bacteria. To improve these assessments, comparative analyses using additional measures such as quantification of differentially culturable tubercle bacteria (DCTB) are required. Essential for enabling this is a comparative measure of TB treatment responses using routine solid and liquid culture with liquid limiting dilutions (LLDs) that detect DCTB in sputum. Methods We recruited treatment-naïve TB patients, with and without HIV-infection, and serially quantified their sputum for DCTB over the course of treatment. Results Serial sputum sampling in 73 individuals during their first 14 days of treatment demonstrated that clearance of DCTB was slower compared to routine solid culture. Treatment response appeared to be characterized by four patterns: (1) Classic bi-phasic bacterial clearance; (2) early non-responders with slower clearance; (3) paradoxical worsening with an increase in bacterial count upon treatment initiation; and (4) non-responders with no change in bacterial load. During treatment, LLDs displayed greater bacterial yield when compared with quantitative solid culture. Upon treatment completion, 74% [46/62] of specimens displayed residual DCTB and within this group, two recurrences were diagnosed. Residual DCTB upon treatment completion was associated with a higher proportion of MGIT culture, GeneXpert, and smear positivity at two months post treatment. No recurrences occurred in the group without residual DCTB. Discussion These data indicate that DCTB assays detect distinct subpopulations of organisms in sputum that are missed by routine solid and liquid culture, and offer important alternatives for efficacy assessments of new TB treatments. The residual DCTB observed upon treatment completion suggests that TB treatment does not always eliminate all bacterial populations, a finding that should be investigated in larger cohorts.
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Affiliation(s)
- Julian S. Peters
- Department of Science and Innovation/National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, The National Health Laboratory Service, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Amanda McIvor
- Department of Science and Innovation/National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, The National Health Laboratory Service, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Andrea O. Papadopoulos
- Department of Science and Innovation/National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, The National Health Laboratory Service, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Tshepiso Masangana
- Department of Science and Innovation/National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, The National Health Laboratory Service, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Bhavna G. Gordhan
- Department of Science and Innovation/National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, The National Health Laboratory Service, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Ziyaad Waja
- Perinatal HIV Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Kennedy Otwombe
- Perinatal HIV Research Unit, University of the Witwatersrand, Johannesburg, South Africa,School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Matebogo Letutu
- Perinatal HIV Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Mireille Kamariza
- Department of Biology, Stanford University, Stanford, CA, United States
| | | | - Carolyn R. Bertozzi
- Department of Chemistry, Stanford University, Stanford, CA, United States,Howard Hughes Medical Institute, Stanford University, Stanford, CA, United States
| | - Neil A. Martinson
- Department of Science and Innovation/National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, The National Health Laboratory Service, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa,Perinatal HIV Research Unit, University of the Witwatersrand, Johannesburg, South Africa,Johns Hopkins University Center for TB Research, Baltimore, MD, United States
| | - Bavesh D. Kana
- Department of Science and Innovation/National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, The National Health Laboratory Service, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa,*Correspondence: Bavesh D. Kana,
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