Serial measurement of M. tuberculosis in blood from critically-ill patients with HIV-associated tuberculosis
David A. Barr,
Charlotte Schutz,
Avuyonke Balfour,
Muki Shey,
Mireille Kamariza,
Carolyn R. Bertozzi,
Timothy J. de Wet,
Ryan Dinkele,
Amy Ward,
Kathryn A. Haigh,
Jean-Paul Kanyik,
Valerie Mizrahi,
Mark P. Nicol,
Robert J. Wilkinson,
David G. Lalloo,
Digby F. Warner,
Graeme Meintjes,
Gerry Davies
Affiliations
David A. Barr
Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory 7925, South Africa; Institute of Infection and Global Health, University of Liverpool, Liverpool L7 3EA, UK; Corresponding author at: Institute of Infection and Global Health, University of Liverpool, Liverpool L7 3EA, UK.
Charlotte Schutz
Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory 7925, South Africa; Department of Medicine, University of Cape Town, Observatory 7925, South Africa
Avuyonke Balfour
Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory 7925, South Africa
Muki Shey
Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory 7925, South Africa; Department of Medicine, University of Cape Town, Observatory 7925, South Africa
Mireille Kamariza
Department of Biology, Stanford University, Stanford, CA 94305, USA
Carolyn R. Bertozzi
Department of Chemistry, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
Timothy J. de Wet
SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine and Department of Pathology, University of Cape Town, Observatory 7925, South Africa
Ryan Dinkele
SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine and Department of Pathology, University of Cape Town, Observatory 7925, South Africa
Amy Ward
Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory 7925, South Africa; Department of Medicine, University of Cape Town, Observatory 7925, South Africa
Kathryn A. Haigh
Institute of Infection and Global Health, University of Liverpool, Liverpool L7 3EA, UK
Jean-Paul Kanyik
Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory 7925, South Africa; Khayelitsha Hospital, Department of Medicine, Cape Town, South Africa
Valerie Mizrahi
Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory 7925, South Africa; SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine and Department of Pathology, University of Cape Town, Observatory 7925, South Africa
Mark P. Nicol
Division of Infection and Immunity School of Biomedical Sciences, University of Western Australia, Perth, Australia,; Division of Medical Microbiology, University of Cape Town, Cape Town, South Africa
Robert J. Wilkinson
Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory 7925, South Africa; Department of Medicine, University of Cape Town, Observatory 7925, South Africa; The Francis Crick Institute, London NW1 1AT, UK; Department of Infectious Disease, Imperial College, London W12 0NN, United Kingdom
David G. Lalloo
Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
Digby F. Warner
Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory 7925, South Africa; SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Institute of Infectious Disease and Molecular Medicine and Department of Pathology, University of Cape Town, Observatory 7925, South Africa
Graeme Meintjes
Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory 7925, South Africa; Department of Medicine, University of Cape Town, Observatory 7925, South Africa
Gerry Davies
Institute of Infection and Global Health, University of Liverpool, Liverpool L7 3EA, UK
Summary: Background: Despite being highly prevalent in hospitalised patients with severe HIV-associated tuberculosis (TB) and sepsis, little is known about the mycobacteriology of Mycobacterium tuberculosis bloodstream infection (MTBBSI). We developed methods to serially measure bacillary load in blood and used these to characterise MTBBSI response to anti-TB therapy (ATT) and relationship with mortality. Methods: We established a microscopy method for direct visualisation of M. tuberculosis bacilli in blood using a novel lysis-concentration protocol and the fluorescent probe, 4-N,N-dimethylaminonaphthalimide-trehalose (DMN-Tre). We tested blood using GeneXpert® MTB/RIF-Ultra (Xpert-ultra) and Myco/F lytic culture after processing blood through lysis-wash steps to remove PCR inhibitors and anti-microbial drug carry-over. HIV-positive patients predicted to have MTBBSI gave blood samples 0, 4, 24, 48 and 72 h after ATT initiation. Bacillary loads were quantified using microscopy, Xpert-ultra cycle threshold, and culture time-to-positivity. Pharmacodynamics were modelled using these measures combined on an ordinal scale, including association with 12-week mortality. Findings: M. tuberculosis was detected in 27 of 28 recruited participants; 25 (89%) by blood Xpert-ultra, 22 (79%) by DMN-Tre microscopy, and 21 (75%) by Myco/F lytic blood culture. Eight (29%) participants died by 12-week follow-up. In a combined pharmacodynamic model, predicted probabilities of negative DMN-Tre microscopy, blood Xpert-ultra, or blood culture after 72 h treatment were 0·64, 0·27, and 0·94, respectively, in those who survived, compared with 0·23, 0·06, and 0·71 in those who died (posterior probability of slower clearance of MTBBSI in those that died >0·99). DMN-Tre microscopy of blood demonstrated heterogenous bacillary morphologies, including microcolonies and clumps. Bacillary cell-length varied significantly with ATT exposure (mean cell-length increase 0·13 log-µm/day; 95%CrI 0·10–0·16). Interpretation: Pharmacodynamics of MTBBSI treatment can be captured using DMN-Tre microscopy, blood Xpert-ultra and culture. This could facilitate interventional trials in severe HIV-associated TB. Funding: Wellcome Trust, NIH Fogarty International Center, South African MRC, NIHR(UK), National Research Foundation of South Africa.
