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Madadi-Goli N, Ahmadi K, Kamakoli MK, Azizi M, Khanipour S, Dizaji SP, Nasehi M, Siadat SD, Fateh A, Vaziri F. The importance of heteroresistance and efflux pumps in bedaquiline-resistant Mycobacterium tuberculosis isolates from Iran. Ann Clin Microbiol Antimicrob 2024; 23:36. [PMID: 38664815 PMCID: PMC11046812 DOI: 10.1186/s12941-024-00694-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 04/04/2024] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND Tuberculosis (TB) continues to pose a threat to communities worldwide and remains a significant public health issue in several countries. We assessed the role of heteroresistance and efflux pumps in bedaquiline (BDQ)-resistant Mycobacterium tuberculosis isolates. METHODS Nineteen clinical isolates were included in the study, of which fifteen isolates were classified as MDR or XDR, while four isolates were fully susceptible. To evaluate BDQ heteroresistance, the Microplate Alamar Blue Assay (MABA) method was employed. For screening mixed infections, MIRU-VNTR was performed on clinical isolates. Mutations in the atpE and Rv0678 genes were determined based on next-generation sequencing data. Additionally, real-time PCR was applied to assess the expression of efflux pump genes in the absence and presence of verapamil (VP). RESULTS All 15 drug-resistant isolates displayed resistance to BDQ. Among the 19 total isolates, 21.05% (4/19) exhibited a heteroresistance pattern to BDQ. None of the isolates carried a mutation of the atpE and Rv0678 genes associated with BDQ resistance. Regarding the MIRU-VNTR analysis, most isolates (94.73%) showed the Beijing genotype. Fifteen (78.9%) isolates showed a significant reduction in BDQ MIC after VP treatment. The efflux pump genes of Rv0676c, Rv1258c, Rv1410c, Rv1634, Rv1819, Rv2459, Rv2846, and Rv3065 were overexpressed in the presence of BDQ. CONCLUSIONS Our results clearly demonstrated the crucial role of heteroresistance and efflux pumps in BDQ resistance. Additionally, we established a direct link between the Rv0676c gene and BDQ resistance. The inclusion of VP significantly reduced the MIC of BDQ in both drug-susceptible and drug-resistant clinical isolates.
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Affiliation(s)
- Nahid Madadi-Goli
- Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, No. 358, 12th Farvardin Ave., Jomhoori St, Tehran, 1316943551, Iran
- Microbiology Research Center (MRC), Pasteur Institute of Iran, Tehran, Iran
- Student Research Committee, Pasteur Institute of Iran, Tehran, Iran
| | - Kamal Ahmadi
- Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, No. 358, 12th Farvardin Ave., Jomhoori St, Tehran, 1316943551, Iran
- Microbiology Research Center (MRC), Pasteur Institute of Iran, Tehran, Iran
- Department of Microbiology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
- Student Research Committee, Pasteur Institute of Iran, Tehran, Iran
| | - Mansour Kargarpour Kamakoli
- Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, No. 358, 12th Farvardin Ave., Jomhoori St, Tehran, 1316943551, Iran
- Microbiology Research Center (MRC), Pasteur Institute of Iran, Tehran, Iran
| | - Mohsen Azizi
- Department of Microbiology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Sharareh Khanipour
- Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, No. 358, 12th Farvardin Ave., Jomhoori St, Tehran, 1316943551, Iran
- Microbiology Research Center (MRC), Pasteur Institute of Iran, Tehran, Iran
| | - Shahin Pourazar Dizaji
- Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, No. 358, 12th Farvardin Ave., Jomhoori St, Tehran, 1316943551, Iran
- Microbiology Research Center (MRC), Pasteur Institute of Iran, Tehran, Iran
| | - Mahshid Nasehi
- Department of Epidemiology and Biostatistics, School of Public Health, Iran University of Medical Sciences, Tehran, Iran
- Center for Communicable Diseases Control, Ministry of Health and Medical Education, Tehran, Iran
| | - Seyed Davar Siadat
- Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, No. 358, 12th Farvardin Ave., Jomhoori St, Tehran, 1316943551, Iran
- Microbiology Research Center (MRC), Pasteur Institute of Iran, Tehran, Iran
| | - Abolfazl Fateh
- Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, No. 358, 12th Farvardin Ave., Jomhoori St, Tehran, 1316943551, Iran.
- Microbiology Research Center (MRC), Pasteur Institute of Iran, Tehran, Iran.
| | - Farzam Vaziri
- Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, No. 358, 12th Farvardin Ave., Jomhoori St, Tehran, 1316943551, Iran.
- Microbiology Research Center (MRC), Pasteur Institute of Iran, Tehran, Iran.
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Komakech K, Nakiyingi L, Fred A, Achan B, Joloba M, Kirenga BJ, Ssengooba W. Effect of mixed Mycobacterium tuberculosis infection on rapid molecular diagnostics among patients starting MDR-TB treatment in Uganda. BMC Infect Dis 2024; 24:70. [PMID: 38200467 PMCID: PMC10782568 DOI: 10.1186/s12879-023-08968-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 12/30/2023] [Indexed: 01/12/2024] Open
Abstract
BACKGROUND Mixed M. tuberculosis (MTB) infection occurs when one is infected with more than one clonally distinct MTB strain. This form of infection can assist MTB strains to acquire additional mutations, facilitate the spread of drug-resistant strains, and boost the rate of treatment failure. Hence, the presence of mixed MTB infection could affect the performance of some rapid molecular diagnostic tests such as Line Probe Assay (LPA) and GeneXpert MTB/RIF (Xpert) assays. METHODS This was a cross-sectional study that used sputum specimens collected from participants screened for STREAM 2 clinical trial between October 2017 and October 2019. Samples from 62 MTB smear-positive patients and rifampicin-resistant patients from peripheral health facilities were processed for Xpert and LPA as screening tests for eligibility in the trial. From November 2020, processed stored sputum samples were retrieved and genotyped to determine the presence of mixed-MTB strain infection using a standard 24-locus Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem-Repeat (MIRU-VNTR). Samples with at least 20/24 MIRU-VNTR loci amplified were considered for analysis. Agar proportional Drug Susceptibility Test (DST) was performed on culture isolates of samples that had discordant results between LPA and Xpert. The impact of the presence of mixed-MTB strain on Xpert and LPA test interpretation was analyzed. RESULTS A total of 53/62 (85%) samples had analyzable results from MIRU-VNTR. The overall prevalence of mixed-MTB infection was 5/53 (9.4%). The prevalence was highest among male's 3/31 (9.7%) and among middle-aged adults, 4/30 (33.3%). Lineage 4 of MTB contributed 3/5 (60.0%) of the mixed-MTB infection prevalence. Having mixed MTB strain infection increased the odds of false susceptible Xpert test results (OR 7.556, 95% CI 0.88-64.44) but not for LPA. Being HIV-positive (P = 0.04) independently predicted the presence of mixed MTB infection. CONCLUSIONS The presence of mixed-MTB strain infection may affect the performance of the GeneXpert test but not for LPA. For patients with high pre-test probability of rifampicin resistance, an alternative rapid method such as LPA should be considered.
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Affiliation(s)
- Kevin Komakech
- Department of Medical Microbiology, Mycobacteriology (BSL-3) Laboratory, Makerere University, Kampala, Uganda
| | - Lydia Nakiyingi
- Department of Medicine, School of Medicine, Makerere University, Kampala, Uganda
| | - Ashab Fred
- Department of Immunology and Molecular Biology, Makerere University, Kampala, Uganda
| | - Beatrice Achan
- Department of Medical Microbiology, Mycobacteriology (BSL-3) Laboratory, Makerere University, Kampala, Uganda
| | - Moses Joloba
- Department of Immunology and Molecular Biology, Makerere University, Kampala, Uganda
| | - Bruce J Kirenga
- Makerere University Lung Institute, Makerere University College of Health Sciences, Kampala, Uganda
| | - Willy Ssengooba
- Department of Medical Microbiology, Mycobacteriology (BSL-3) Laboratory, Makerere University, Kampala, Uganda.
- Makerere University Lung Institute, Makerere University College of Health Sciences, Kampala, Uganda.
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Sharma D, Pooja, Nirban S, Ojha S, Kumar T, Jain N, Mohamad N, Kumar P, Pandey M. Nano vs Resistant Tuberculosis: Taking the Lung Route. AAPS PharmSciTech 2023; 24:252. [PMID: 38049695 DOI: 10.1208/s12249-023-02708-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 11/19/2023] [Indexed: 12/06/2023] Open
Abstract
Tuberculosis (TB) is among the top 10 infectious diseases worldwide. It is categorized among the leading killer diseases that are the reason for the death of millions of people globally. Although a standardized treatment regimen is available, non-adherence to treatment has increased multi-drug resistance (MDR) and extensive drug-resistant (XDR) TB development. Another challenge is targeting the death of TB reservoirs in the alveoli via conventional treatment. TB Drug resistance may emerge as a futuristic restraint of TB with the scarcity of effective Anti-tubercular drugs. The paradigm change towards nano-targeted drug delivery systems is mostly due to the absence of effective therapy and increased TB infection recurrent episodes with MDR. The emerging field of nanotechnology gave an admirable opportunity to combat MDR and XDR via accurate diagnosis with effective treatment. The new strategies targeting the lung via the pulmonary route may overcome the new incidence of MDR and enhance patient compliance. Therefore, this review highlights the importance and recent research on pulmonary drug delivery with nanotechnology along with prevalence, the need for the development of nanotechnology, beneficial aspects of nanomedicine, safety concerns of nanocarriers, and clinical studies.
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Affiliation(s)
- Deepika Sharma
- Department of Pharmaceutical Sciences, Central University of Haryana, Mahendergarh, 123031, Haryana, India
| | - Pooja
- Department of Pharmaceutical Sciences, Central University of Haryana, Mahendergarh, 123031, Haryana, India
| | - Sunita Nirban
- Department of Pharmaceutical Sciences, Central University of Haryana, Mahendergarh, 123031, Haryana, India
| | - Smriti Ojha
- Department of Pharmaceutical Science and Technology, Madan Mohan Malaviya University of Technology, Gorakhpur, India
| | - Tarun Kumar
- Department of Pharmaceutical Sciences, Central University of Haryana, Mahendergarh, 123031, Haryana, India
| | - Neha Jain
- Department of Pharmaceutics, Amity Institute of Pharmacy, Amity University, Noida, India
| | - Najwa Mohamad
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, University of Cyberjaya, Persiaran Bestari, 63000, Cyberjaya, Selangor Darul Ehsan, Malaysia
| | - Pradeep Kumar
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 7 York Road, Parktown, 2193, South Africa
| | - Manisha Pandey
- Department of Pharmaceutical Sciences, Central University of Haryana, Mahendergarh, 123031, Haryana, India.
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Komakech K, Nakiyingi L, Fred A, Achan B, Joloba M, Kirenga BJ, Ssengooba W. Effect of mixed Mycobacterium tuberculosis infection on rapid molecular diagnostics among patients starting MDR-TB treatment in Uganda. RESEARCH SQUARE 2023:rs.3.rs-3324330. [PMID: 37841871 PMCID: PMC10571598 DOI: 10.21203/rs.3.rs-3324330/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
Background We evaluated the effect of mixed-MTB strain infection on the performance of Line Probe Assay (LPA) and GeneXpert MTB/RIF (Xpert) assays among patients initiating MDR-TB treatment in Uganda. Methods This was a cross-sectional study using sputum specimens collected from participants screened for STREAM 2 clinical trial between October 2017 and October 2019. Samples from 62 MTB smear-positive patients and rifampicin-resistant patients from the peripheral health facilities were processed for Xpert and LPA as screening tests for eligibility in the trial. From November 2020, processed stored sputum samples were retrieved and genotyped to determine the presence of mixed-MTB strain infection using a standard 24-locus Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem-Repeat (MIRU-VNTR). Samples with at least 20/24 MIRU-VNTR loci amplified were considered for analysis. Agar proportional Drug Susceptibility Test (DST) was performed on culture isolates of samples that had discordant results between LPA and Xpert. The impact of the presence of mixed-MTB strain on Xpert and LPA test interpretation was analyzed. Results A total of 53/62 (85%) samples had analyzable results from MIRU-VNTR. The overall prevalence of mixed-MTB infection was 5/53 (9.4%). The prevalence was highest among males 3/33 (9.7%) and among middle-aged adults, 4/30 (13.3%). Lineage 4 of MTB contributed 3/33 (9.1%) of the mixed-MTB infection prevalence. Having mixed MTB strain infection increased the odds of false susceptible Xpert test results (OR 7.556, 95% CI 0.88-64.44) but not for LPA. Being HIV-positive (P=0.04) independently predicted the presence of mixed MTB infection. Conclusions The presence of mixed-MTB strain infection may affect the performance of the GeneXpert test but not for LPA. For patients with high pre-test probability of rifampicin resistance, an alternative rapid method such as LPA should be considered.
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Affiliation(s)
| | | | | | | | | | - Bruce J Kirenga
- Makerere University Lung Institute, Makerere University College of Health Sciences
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Dlamini TC, Mkhize BT, Sydney C, Maningi NE, Malinga LA. Molecular investigations of Mycobacterium tuberculosis genotypes among baseline and follow-up strains circulating in four regions of Eswatini. BMC Infect Dis 2023; 23:566. [PMID: 37644382 PMCID: PMC10466871 DOI: 10.1186/s12879-023-08546-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Accepted: 08/18/2023] [Indexed: 08/31/2023] Open
Abstract
BACKGROUND The tuberculosis (TB) epidemic remains a major global health problem and Eswatini is not excluded. Our study investigated the circulating genotypes in Eswatini and compared them at baseline (start of treatment) and follow-up during TB treatment. METHODS Three hundred and ninety (n = 390) participants were prospectively enrolled from referral clinics and patients who met the inclusion criteria, were included in the study. A total of 103 participants provided specimens at baseline and follow-up within six months. Mycobacterium tuberculosis (M.tb) strains were detected by GeneXpert® MTB/RIF assay (Cephied, USA) and Ziehl -Neelsen (ZN) microscopy respectively at baseline and follow-up time-points respectively. The 206 collected specimens were decontaminated and cultured on BACTEC™ MGIT™ 960 Mycobacteria Culture System (Becton Dickinson, USA). Drug sensitivity testing was performed at both baseline and follow-up time points. Spoligotyping was performed on both baseline and follow-up strains after DNA extraction. RESULTS Resistance to at least one first line drug was detected higher at baseline compared to follow-up specimens with most of them developing into multidrug-resistant (MDR)-TB. A total of four lineages and twenty genotypes were detected. The distribution of the lineages varied among the different regions in Eswatini. The Euro-American lineage was the most prevalent with 46.12% (95/206) followed by the East Asian with 24.27% (50/206); Indo-Oceanic at 9.71% (20/206) and Central Asian at 1.94% (4/206). Furthermore, a high proportion of the Beijing genotype at 24.27% (50/206) and S genotype at 16.50% (34/206) were detected. The Beijing genotype was predominant in follow-up specimens collected from the Manzini region with 48.9% (23/47) (p = 0.001). A significant proportion of follow-up specimens developed MDR-TB (p = 0.001) with Beijing being the major genotype in most follow-up specimens (p < 0.000). CONCLUSION Eswatini has a high M.tb genotypic diversity. A significant proportion of the TB infected participants had the Beijing genotype associated with MDR-TB in follow-up specimens and thus indicate community wide transmission.
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Affiliation(s)
- Talent C Dlamini
- Department of Medical Laboratory Sciences, Southern Africa Nazarene University, Manzini, Eswatini.
- Biomedical and Clinical Technology, Department, Durban University of Technology, Durban, South Africa.
| | - Brenda T Mkhize
- Biomedical and Clinical Technology, Department, Durban University of Technology, Durban, South Africa
| | - Clive Sydney
- Biomedical and Clinical Technology, Department, Durban University of Technology, Durban, South Africa
| | | | - Lesibana A Malinga
- Department of Medical Microbiology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
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Zhdanova S, Jiao WW, Sinkov V, Khromova P, Solovieva N, Mushkin A, Mokrousov I, Belopolskaya O, Masharsky A, Vyazovaya A, Rychkova L, Kolesnikova L, Zhuravlev V, Shen AD, Ogarkov O. Insight into Population Structure and Drug Resistance of Pediatric Tuberculosis Strains from China and Russia Gained through Whole-Genome Sequencing. Int J Mol Sci 2023; 24:10302. [PMID: 37373451 DOI: 10.3390/ijms241210302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/07/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
This study aimed to determine phenotypic and genotypic drug resistance patterns of Mycobacterium tuberculosis strains from children with tuberculosis (TB) in China and Russia, two high-burden countries for multi/extensively-drug resistant (MDR/XDR) TB. Whole-genome sequencing data of M. tuberculosis isolates from China (n = 137) and Russia (n = 60) were analyzed for phylogenetic markers and drug-resistance mutations, followed by comparison with phenotypic susceptibility data. The Beijing genotype was detected in 126 Chinese and 50 Russian isolates. The Euro-American lineage was detected in 10 Russian and 11 Chinese isolates. In the Russian collection, the Beijing genotype and Beijing B0/W148-cluster were dominated by MDR strains (68% and 94%, respectively). Ninety percent of B0/W148 strains were phenotypically pre-XDR. In the Chinese collection, neither of the Beijing sublineages was associated with MDR/pre-XDR status. MDR was mostly caused by low fitness cost mutations (rpoB S450L, katG S315T, rpsL K43R). Chinese rifampicin-resistant strains demonstrated a higher diversity of resistance mutations than Russian isolates (p = 0.003). The rifampicin and isoniazid resistance compensatory mutations were detected in some MDR strains, but they were not widespread. The molecular mechanisms of M. tuberculosis adaptation to anti-TB treatment are not unique to the pediatric strains, but they reflect the general situation with TB in Russia and China.
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Affiliation(s)
- Svetlana Zhdanova
- Department of Epidemiology and Microbiology, Scientific Centre for Family Health and Human Reproduction Problems, 664003 Irkutsk, Russia
| | - Wei-Wei Jiao
- National Clinical Research Center for Respiratory Diseases, Beijing Key Laboratory of Pediatric Respiratory Infection Disease, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - Viacheslav Sinkov
- Department of Epidemiology and Microbiology, Scientific Centre for Family Health and Human Reproduction Problems, 664003 Irkutsk, Russia
| | - Polina Khromova
- Department of Epidemiology and Microbiology, Scientific Centre for Family Health and Human Reproduction Problems, 664003 Irkutsk, Russia
| | - Natalia Solovieva
- St. Petersburg Research Institute of Phthisiopulmonology, 191036 St. Petersburg, Russia
| | - Alexander Mushkin
- St. Petersburg Research Institute of Phthisiopulmonology, 191036 St. Petersburg, Russia
| | - Igor Mokrousov
- Laboratory of Molecular Epidemiology and Evolutionary Genetics, St. Petersburg Pasteur Institute, 197101 St. Petersburg, Russia
- Henan International Joint Laboratory of Children's Infectious Diseases, Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital Zhengzhou Children's Hospital, Zhengzhou 450012, China
| | - Olesya Belopolskaya
- The Bio-Bank Resource Center, Research Park, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Aleksey Masharsky
- The Bio-Bank Resource Center, Research Park, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Anna Vyazovaya
- Laboratory of Molecular Epidemiology and Evolutionary Genetics, St. Petersburg Pasteur Institute, 197101 St. Petersburg, Russia
| | - Lubov Rychkova
- Department of Epidemiology and Microbiology, Scientific Centre for Family Health and Human Reproduction Problems, 664003 Irkutsk, Russia
| | - Lubov Kolesnikova
- Department of Epidemiology and Microbiology, Scientific Centre for Family Health and Human Reproduction Problems, 664003 Irkutsk, Russia
| | - Viacheslav Zhuravlev
- St. Petersburg Research Institute of Phthisiopulmonology, 191036 St. Petersburg, Russia
| | - A-Dong Shen
- National Clinical Research Center for Respiratory Diseases, Beijing Key Laboratory of Pediatric Respiratory Infection Disease, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
- Henan International Joint Laboratory of Children's Infectious Diseases, Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital Zhengzhou Children's Hospital, Zhengzhou 450012, China
| | - Oleg Ogarkov
- Department of Epidemiology and Microbiology, Scientific Centre for Family Health and Human Reproduction Problems, 664003 Irkutsk, Russia
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Martinecz A, Boeree MJ, Diacon AH, Dawson R, Hemez C, Aarnoutse RE, Abel Zur Wiesch P. High rifampicin peak plasma concentrations accelerate the slow phase of bacterial decline in tuberculosis patients: Evidence for heteroresistance. PLoS Comput Biol 2023; 19:e1011000. [PMID: 37053266 PMCID: PMC10128972 DOI: 10.1371/journal.pcbi.1011000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 04/25/2023] [Accepted: 03/06/2023] [Indexed: 04/15/2023] Open
Abstract
BACKGROUND Antibiotic treatments are often associated with a late slowdown in bacterial killing. This separates the killing of bacteria into at least two distinct phases: a quick phase followed by a slower phase, the latter of which is linked to treatment success. Current mechanistic explanations for the in vitro slowdown are either antibiotic persistence or heteroresistance. Persistence is defined as the switching back and forth between susceptible and non-susceptible states, while heteroresistance is defined as the coexistence of bacteria with heterogeneous susceptibilities. Both are also thought to cause a slowdown in the decline of bacterial populations in patients and therefore complicate and prolong antibiotic treatments. Reduced bacterial death rates over time are also observed within tuberculosis patients, yet the mechanistic reasons for this are unknown and therefore the strategies to mitigate them are also unknown. METHODS AND FINDINGS We analyse a dose ranging trial for rifampicin in tuberculosis patients and show that there is a slowdown in the decline of bacteria. We show that the late phase of bacterial killing depends more on the peak drug concentrations than the total drug exposure. We compare these to pharmacokinetic-pharmacodynamic models of rifampicin heteroresistance and persistence. We find that the observation on the slow phase's dependence on pharmacokinetic measures, specifically peak concentrations are only compatible with models of heteroresistance and incompatible with models of persistence. The quantitative agreement between heteroresistance models and observations is very good ([Formula: see text]). To corroborate the importance of the slowdown, we validate our results by estimating the time to sputum culture conversion and compare the results to a different dose ranging trial. CONCLUSIONS Our findings indicate that higher doses, specifically higher peak concentrations may be used to optimize rifampicin treatments by accelerating bacterial killing in the slow phase. It adds to the growing body of literature supporting higher rifampicin doses for shortening tuberculosis treatments.
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Affiliation(s)
- Antal Martinecz
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
- Center for Infectious Disease Dynamics, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Martin J Boeree
- Department of Lung Diseases, Radboud Institute for Health Sciences, Radboud university medical center, Nijmegen, the Netherlands
| | - Andreas H Diacon
- Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, South Africa
- TASK Applied Science, Cape Town, South Africa
| | - Rodney Dawson
- Division of Pulmonology and Department of Medicine, University of Cape Town, Cape Town, South Africa
- University of Cape Town Lung Institute, Cape Town, South Africa
| | - Colin Hemez
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
- Graduate program in Biophysics, Harvard University, Boston, Massachusetts, United States of America
| | - Rob E Aarnoutse
- Department of Pharmacy, Radboud Institute for Health Sciences, Radboud university medical center, Nijmegen, The Netherlands
| | - Pia Abel Zur Wiesch
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway
- Center for Infectious Disease Dynamics, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biology, Eberly College of Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Norwegian Institute of Public Health (Folkehelseinstitutt), Oslo, Norway
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