1
|
McIvor A, Gordhan BG, Waja Z, Otwombe K, Martinson NA, Kana BD. Supplementation of sputum cultures with culture filtrate to detect tuberculosis in a cross-sectional study of HIV-infected individuals. Tuberculosis (Edinb) 2021; 129:102103. [PMID: 34144375 DOI: 10.1016/j.tube.2021.102103] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 03/02/2021] [Accepted: 06/09/2021] [Indexed: 10/21/2022]
Abstract
While some healthcare systems have shifted to molecular diagnostics, culture still remains the gold standard for tuberculosis diagnosis, but it is limited by its long duration to a positive result. Methods to reduce time to culture positivity (TTP) are urgently required. We determined if growth factor supplementation in the mycobacterial growth indicator tube (MGIT) culture system reduces TTP. MGITs were supplemented with fresh culture filtrate (CF) as a source of growth stimulatory molecules from axenic Mycobacterium tuberculosis culture. Different volumes of CF and media components were tested. The performance of these modified MGITs was assessed with sputum from HIV-TB co-infected individuals. Reducing the volume of MGIT cultures and removal of detergent from cultures grown to generate CF had a marginal but significant benefit on reducing TTP. In a subset of specimens, CF inhibited growth. Following optimization of methods, a reduced TTP occurred in specimens with low bacillary load as measured by GeneXpert, smear microscopy and colony forming units. Three specimens that were negative under standard conditions flagged positive following CF supplementation. Our data provide preliminary evidence that addition of CF to MGIT cultures can enhance detection of M. tuberculosis in HIV-TB co-infected patients with low sputum bacillary loads.
Collapse
Affiliation(s)
- Amanda McIvor
- DST/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, South Africa
| | - Bhavna Gowan Gordhan
- DST/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, South Africa
| | - Ziyaad Waja
- Perinatal HIV Research Unit (PHRU), University of the Witwatersrand, Johannesburg, South Africa
| | - Kennedy Otwombe
- Perinatal HIV Research Unit (PHRU), University of the Witwatersrand, Johannesburg, South Africa; School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, South Africa
| | - Neil A Martinson
- DST/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, South Africa; Perinatal HIV Research Unit (PHRU), University of the Witwatersrand, Johannesburg, South Africa; John Hopkins University, Centre for Tuberculosis Research, Baltimore, MD, USA
| | - Bavesh Davandra Kana
- DST/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, South Africa; CAPRISA, Centre for the AIDS Programme of Research in South Africa, Durban, South Africa.
| |
Collapse
|