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Tembo G, Mayuni M, Kamng'ona R, Chimgoneko L, Chiwala G, Sichone S, Galafa B, Thole F, Mkandawire C, Chirwa AE, Nsomba E, Nkhoma V, Ngoliwa C, Toto N, Makhaza L, Muyaya A, Kudowa E, Henrion MYR, Dula D, Morton B, Chikaonda T, Gordon SB, Jambo KC. Poor association between 13-valent pneumococcal conjugate vaccine-induced serum and mucosal antibody responses with experimental Streptococcus pneumoniae serotype 6B colonisation. Vaccine 2024; 42:2975-2982. [PMID: 38570270 PMCID: PMC11056720 DOI: 10.1016/j.vaccine.2024.03.055] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 02/23/2024] [Accepted: 03/21/2024] [Indexed: 04/05/2024]
Abstract
BACKGROUND Pneumococcal carriage is the primary reservoir for transmissionand a prerequisite for invasive pneumococcal disease. Pneumococcal Conjugate Vaccine 13 (PCV13) showed a 62% efficacy in protection against experimental Streptococcus pneumoniae serotype 6B (Spn6B) carriage in a controlled human infection model (CHIM) of healthy Malawian adults. We, therefore, measured humoral responses to experimental challenge and PCV-13 vaccination and determined the association with protection against pneumococcal carriage. METHODS We vaccinated 204 young, healthy Malawian adults with PCV13 or placebo and nasally inoculated them with Spn6B at least four weeks post-vaccination to establish carriage. We collected peripheral blood and nasal lining fluid at baseline, 4 weeks post-vaccination (7 days pre-inoculation), 2, 7, 14 and > 1 year post-inoculation. We measured the concentration of anti-serotype 6B Capsular Polysaccharide (CPS) Immunoglobulin G (IgG) and IgA antibodies in serum and nasal lining fluid using the World Health Organization (WHO) standardised enzyme-linked immunosorbent assay (ELISA). RESULTS PCV13-vaccinated adults had higher serum IgG and nasal IgG/IgA anti-Spn6B CPS-specific binding antibodies than placebo recipients 4 to 6 weeks post-vaccination, which persisted for at least a year after vaccination. Nasal challenge with Spn6B did not significantly alter serum or nasal anti-CPS IgG binding antibody titers with or without experimental pneumococcal carriage. Pre-challenge titers of PCV13-induced serum IgG and nasal IgG/IgA anti-Spn6B CPS binding antibodies did not significantly differ between those that got experimentally colonised by Spn6B compared to those that did not. CONCLUSION This study demonstrates that despite high PCV13 efficacy against experimental Spn6B carriage in young, healthy Malawian adults, robust vaccine-induced systemic and mucosal anti-Spn6B CPS binding antibodies did not directly relate to protection.
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Affiliation(s)
- G Tembo
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi.
| | - M Mayuni
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - R Kamng'ona
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - L Chimgoneko
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - G Chiwala
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - S Sichone
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - B Galafa
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - F Thole
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - C Mkandawire
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - A E Chirwa
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - E Nsomba
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - V Nkhoma
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - C Ngoliwa
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - N Toto
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - L Makhaza
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - A Muyaya
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - E Kudowa
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - M Y R Henrion
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi; Liverpool School of Tropical Medicine, Clinical Sciences Department, Pembroke Place, Liverpool, UK
| | - D Dula
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - B Morton
- Liverpool School of Tropical Medicine, Clinical Sciences Department, Pembroke Place, Liverpool, UK
| | - T Chikaonda
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi
| | - S B Gordon
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi; Liverpool School of Tropical Medicine, Clinical Sciences Department, Pembroke Place, Liverpool, UK
| | - K C Jambo
- Malawi-Liverpool-Wellcome Research Programme, Blantyre, Malawi; Liverpool School of Tropical Medicine, Clinical Sciences Department, Pembroke Place, Liverpool, UK.
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Doherty K, Dula D, Chirwa A, Nsomba E, Nkhoma VS, Toto N, Chikaonda T, Kamng'ona R, Phiri J, Reiné J, Ndaferankhande J, Makhaza L, Banda P, Jambo K, Ferreira DM, Gordon SB. Experimental pneumococcal carriage in people living with HIV in Malawi: the first controlled human infection model in a key at-risk population. Wellcome Open Res 2024; 9:2. [PMID: 38362541 PMCID: PMC10864820 DOI: 10.12688/wellcomeopenres.19949.1] [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] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2023] [Indexed: 02/17/2024] Open
Abstract
Background: As well as suffering a high burden of pneumococcal disease people living with HIV (PLHIV) may contribute to community transmission in sub-Saharan African (sSA) settings. Pneumococcal vaccination is not currently offered to PLHIV in sSA but may prevent disease and reduce transmission. More evidence of vaccine effectiveness against carriage in PLHIV is needed. An Experimental Human Pneumococcal Carriage model (EHPC) has been safely and acceptably used in healthy adults in Malawi to evaluate pneumococcal vaccines against carriage and to identify immune correlates of protection from carriage. This study will establish the same model in PLHIV and will be the first controlled human infection model (CHIM) in this key population. Methods: Healthy participants with and without HIV will be inoculated intranasally with Streptococcus pneumoniae serotype 6B. Sequential cohorts will be challenged with increasing doses to determine the optimal safe challenge dose to establish experimental carriage. Nasal fluid, nasal mucosal, and blood samples will be taken before inoculation and on days 2, 7, 14, and 21 following inoculation to measure pneumococcal carriage density and identify immune correlates of protection from carriage. The vast majority of natural pneumococcal carriage events in PLHIV do not result in invasive disease and no invasive disease is expected in this study. However, robust participant safety monitoring is designed to identify signs of invasive disease early should they develop, and to implement treatment immediately. Participants will complete a Likert-style questionnaire at study-end to establish acceptability. Interpretations: We expect the EHPC model to be safely and acceptably implemented in PLHIV. The CHIM can then be used to accelerate pneumococcal vaccine evaluations in this population, and an evidence-based pneumococcal vaccination policy for PLHIV in sSA.
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Affiliation(s)
- Klara Doherty
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Southern Region, Malawi
- Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Dingase Dula
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Southern Region, Malawi
| | - Anthony Chirwa
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Southern Region, Malawi
| | - Edna Nsomba
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Southern Region, Malawi
| | - Vitumbiko S. Nkhoma
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Southern Region, Malawi
| | - Neema Toto
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Southern Region, Malawi
| | - Tarsizio Chikaonda
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Southern Region, Malawi
| | - Raphael Kamng'ona
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Southern Region, Malawi
| | - Joseph Phiri
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Southern Region, Malawi
| | - Jesús Reiné
- Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
- Oxford Vaccine Group, University of Oxford, Oxford, England, UK
| | - John Ndaferankhande
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Southern Region, Malawi
| | - Lumbani Makhaza
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Southern Region, Malawi
| | - Peter Banda
- Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Kondwani Jambo
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Southern Region, Malawi
- Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Daniela M Ferreira
- Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
- Oxford Vaccine Group, University of Oxford, Oxford, England, UK
| | - Stephen B Gordon
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Southern Region, Malawi
- Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
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3
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Dula D, Morton B, Chikaonda T, Chirwa AE, Nsomba E, Nkhoma V, Ngoliwa C, Sichone S, Galafa B, Tembo G, Chaponda M, Toto N, Kamng'ona R, Makhaza L, Muyaya A, Thole F, Kudowa E, Howard A, Kenny-Nyazika T, Ndaferankhande J, Mkandawire C, Chiwala G, Chimgoneko L, Banda NPK, Rylance J, Ferreira D, Jambo K, Henrion MYR, Gordon SB. Effect of 13-valent pneumococcal conjugate vaccine on experimental carriage of Streptococcus pneumoniae serotype 6B in Blantyre, Malawi: a randomised controlled trial and controlled human infection study. Lancet Microbe 2023; 4:e683-e691. [PMID: 37659418 PMCID: PMC10469263 DOI: 10.1016/s2666-5247(23)00178-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 06/01/2023] [Accepted: 06/02/2023] [Indexed: 09/04/2023]
Abstract
BACKGROUND The effect of childhood pneumococcal conjugate vaccine implementation in Malawi is threatened by absence of herd effect. There is persistent vaccine-type pneumococcal carriage in both vaccinated children and the wider community. We aimed to use a human infection study to measure 13-valent pneumococcal conjugate vaccine (PCV13) efficacy against pneumococcal carriage. METHODS We did a double-blind, parallel-arm, randomised controlled trial investigating the efficacy of PCV13 or placebo against experimental pneumococcal carriage of Streptococcus pneumoniae serotype 6B (strain BHN418) among healthy adults (aged 18-40 years) from Blantyre, Malawi. We randomly assigned participants (1:1) to receive PCV13 or placebo. PCV13 and placebo doses were prepared by an unmasked pharmacist to maintain research team and participant masking with identification only by a randomisation identification number and barcode. 4 weeks after receiving either PCV13 or placebo, participants were challenged with 20 000 colony forming units (CFUs) per naris, 80 000 CFUs per naris, or 160 000 CFUs per naris by intranasal inoculation. The primary endpoint was experimental pneumococcal carriage, established by culture of nasal wash at 2, 7, and 14 days. Vaccine efficacy was estimated per protocol by means of a log-binomial model adjusting for inoculation dose. The trial is registered with the Pan African Clinical Trials Registry, PACTR202008503507113, and is now closed. FINDINGS Recruitment commenced on April 27, 2021 and the final visit was completed on Sept 12, 2022. 204 participants completed the study protocol (98 PCV13, 106 placebo). There were lower carriage rates in the vaccine group at all three inoculation doses (0 of 21 vs two [11%] of 19 at 20 000 CFUs per naris; six [18%] of 33 vs 12 [29%] of 41 at 80 000 CFUs per naris, and four [9%] of 44 vs 16 [35%] of 46 at 160 000 CFUs per naris). The overall carriage rate was lower in the vaccine group compared with the placebo group (ten [10%] of 98 vs 30 [28%] of 106; Fisher's p value=0·0013) and the vaccine efficacy against carriage was estimated at 62·4% (95% CI 27·7-80·4). There were no severe adverse events related to vaccination or inoculation of pneumococci. INTERPRETATION This is, to our knowledge, the first human challenge study to test the efficacy of a pneumococcal vaccine against pneumococcal carriage in Africa, which can now be used to establish vaccine-induced correlates of protection and compare alternative strategies to prevent pneumococcal carriage. This powerful tool could lead to new means to enhance reduction in pneumococcal carriage after vaccination. FUNDING Wellcome Trust.
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Affiliation(s)
- Dingase Dula
- Malawi Liverpool Wellcome Research Programme, Blantyre, Malawi
| | - Ben Morton
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK; Critical Care Department, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK.
| | | | | | - Edna Nsomba
- Malawi Liverpool Wellcome Research Programme, Blantyre, Malawi
| | | | - Clara Ngoliwa
- Malawi Liverpool Wellcome Research Programme, Blantyre, Malawi; Department of Medicine, Queen Elizabeth Central Hospital, Blantyre, Malawi
| | - Simon Sichone
- Malawi Liverpool Wellcome Research Programme, Blantyre, Malawi
| | | | - Godwin Tembo
- Malawi Liverpool Wellcome Research Programme, Blantyre, Malawi
| | | | - Neema Toto
- Malawi Liverpool Wellcome Research Programme, Blantyre, Malawi
| | | | - Lumbani Makhaza
- Malawi Liverpool Wellcome Research Programme, Blantyre, Malawi
| | - Alfred Muyaya
- Malawi Liverpool Wellcome Research Programme, Blantyre, Malawi
| | - Faith Thole
- Malawi Liverpool Wellcome Research Programme, Blantyre, Malawi
| | | | - Ashleigh Howard
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Tinashe Kenny-Nyazika
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | | | | | - Gift Chiwala
- Malawi Liverpool Wellcome Research Programme, Blantyre, Malawi
| | | | - Ndaziona P K Banda
- Department of Medicine, Queen Elizabeth Central Hospital, Blantyre, Malawi; School of Medicine, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Jamie Rylance
- Malawi Liverpool Wellcome Research Programme, Blantyre, Malawi
| | - Daniela Ferreira
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK; Department of Paediatrics, University of Oxford, Oxford, UK
| | - Kondwani Jambo
- Malawi Liverpool Wellcome Research Programme, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Marc Y R Henrion
- Malawi Liverpool Wellcome Research Programme, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Stephen B Gordon
- Malawi Liverpool Wellcome Research Programme, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
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4
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Sephton-Clark P, Tenor JL, Toffaletti DL, Meyers N, Giamberardino C, Molloy SF, Palmucci JR, Chan A, Chikaonda T, Heyderman R, Hosseinipour M, Kalata N, Kanyama C, Kukacha C, Lupiya D, Mwandumba HC, Harrison T, Bicanic T, Perfect JR, Cuomo CA. Genomic Variation across a Clinical Cryptococcus Population Linked to Disease Outcome. mBio 2022; 13:e0262622. [PMID: 36354332 PMCID: PMC9765290 DOI: 10.1128/mbio.02626-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 10/13/2022] [Indexed: 11/12/2022] Open
Abstract
Cryptococcus neoformans is the causative agent of cryptococcosis, a disease with poor patient outcomes that accounts for approximately 180,000 deaths each year. Patient outcomes may be impacted by the underlying genetics of the infecting isolate; however, our current understanding of how genetic diversity contributes to clinical outcomes is limited. Here, we leverage clinical, in vitro growth and genomic data for 284 C. neoformans isolates to identify clinically relevant pathogen variants within a population of clinical isolates from patients with human immunodeficiency virus (HIV)-associated cryptococcosis in Malawi. Through a genome-wide association study (GWAS) approach, we identify variants associated with the fungal burden and the growth rate. We also find both small and large-scale variation, including aneuploidy, associated with alternate growth phenotypes, which may impact the course of infection. Genes impacted by these variants are involved in transcriptional regulation, signal transduction, glycosylation, sugar transport, and glycolysis. We show that growth within the central nervous system (CNS) is reliant upon glycolysis in an animal model and likely impacts patient mortality, as the CNS yeast burden likely modulates patient outcome. Additionally, we find that genes with roles in sugar transport are enriched in regions under selection in specific lineages of this clinical population. Further, we demonstrate that genomic variants in two genes identified by GWAS impact virulence in animal models. Our approach identifies links between the genetic variation in C. neoformans and clinically relevant phenotypes and animal model pathogenesis, thereby shedding light on specific survival mechanisms within the CNS and identifying the pathways involved in yeast persistence. IMPORTANCE Infection outcomes for cryptococcosis, most commonly caused by C. neoformans, are influenced by host immune responses as well as by host and pathogen genetics. Infecting yeast isolates are genetically diverse; however, we lack a deep understanding of how this diversity impacts patient outcomes. To better understand both clinical isolate diversity and how diversity contributes to infection outcomes, we utilize a large collection of clinical C. neoformans samples that were isolated from patients enrolled in a clinical trial across 3 hospitals in Malawi. By combining whole-genome sequence data, clinical data, and in vitro growth data, we utilize genome-wide association approaches to examine the genetic basis of virulence. Genes with significant associations display virulence attributes in both murine and rabbit models, demonstrating that our approach can identify potential links between genetic variants and patho-biologically significant phenotypes.
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Affiliation(s)
- Poppy Sephton-Clark
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Jennifer L. Tenor
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Dena L. Toffaletti
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Nancy Meyers
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Charles Giamberardino
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Síle F. Molloy
- Centre for Global Health, Institute of Infection and Immunity, St George's University of London, London, United Kingdom
- Clinical Academic Group in Infection, St George's University Hospital, London, United Kingdom
| | - Julia R. Palmucci
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Adrienne Chan
- Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Tarsizio Chikaonda
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Robert Heyderman
- Division of Infection and Immunity, University College London, London, United Kingdom
| | - Mina Hosseinipour
- UNC Project Malawi, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Newton Kalata
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Cecilia Kanyama
- UNC Project Malawi, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Christopher Kukacha
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Duncan Lupiya
- Tisungane Clinic, Zomba Central Hospital, Zomba, Malawi
| | - Henry C. Mwandumba
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Thomas Harrison
- Centre for Global Health, Institute of Infection and Immunity, St George's University of London, London, United Kingdom
- Clinical Academic Group in Infection, St George's University Hospital, London, United Kingdom
| | - Tihana Bicanic
- Centre for Global Health, Institute of Infection and Immunity, St George's University of London, London, United Kingdom
- Clinical Academic Group in Infection, St George's University Hospital, London, United Kingdom
| | - John R. Perfect
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Christina A. Cuomo
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
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5
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Matoga M, Chen JS, Krysiak R, Ndalama B, Massa C, Bonongwe N, Mathiya E, Kamtambe B, Jere E, Chikaonda T, Golparian D, Unemo M, Cohen MS, Hobbs MM, Hoffman IF. Gentamicin Susceptibility in Neisseria gonorrhoeae and Treatment Outcomes for Urogenital Gonorrhea After 25 Years of Sustained Gentamicin Use in Malawi. Sex Transm Dis 2022; 49:251-256. [PMID: 34772893 PMCID: PMC8940620 DOI: 10.1097/olq.0000000000001580] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Gentamicin has been used for the treatment of gonorrhea in Malawi since 1993. However, declining clinical cure rates have been suspected. We evaluated current Neisseria gonorrhoeae susceptibility to gentamicin in vitro and clinically. METHODS Men with acute urethritis were recruited at the Bwaila District Hospital STI Clinic in Lilongwe, Malawi, between January 2017 and August 2019. All men provided urethral swabs for etiological testing at enrollment and test of cure (TOC), 1 week later, using Gram-stained microscopy and culture. We used Etest to determine minimum inhibitory concentrations (MICs) of gentamicin, azithromycin, cefixime, ceftriaxone, ciprofloxacin, and spectinomycin; disc diffusion for tetracycline susceptibility; and whole-genome sequencing (WGS) to verify/refute treatment failure. RESULTS Among 183 N. gonorrhoeae culture-positive men enrolled, 151 (82.5%) had a swab taken for TOC. Of these 151 men, 16 (10.6%) had a positive culture at TOC. One hundred forty-one baseline isolates were tested for gentamicin susceptibility using Etest: 2 (1.4%), MIC = 2 μg/mL; 111 (78.7%), MIC = 4 μg/mL; and 28 (19.9%), MIC = 8 μg/mL. All isolates were susceptible to azithromycin, cefixime, ceftriaxone, and spectinomycin, whereas 63.1% had intermediate susceptibility or resistance to ciprofloxacin. Almost all (96.1%) isolates were resistant to tetracycline. All examined isolates cultured at TOC (n = 13) had gentamicin MICs ≤8 μg/mL. Ten men had pretreatment and posttreatment isolates examined by whole-genome sequencing; 2 (20%) were verified new infections (4119 and 1272 single-nucleotide polymorphisms), whereas 8 (80%) were confirmed treatment failures (0-1 single-nucleotide polymorphism). CONCLUSIONS Gentamicin MICs poorly predict gonorrhea treatment outcome with gentamicin, and treatment failures are verified with gonococcal strains with in vitro susceptibility to gentamicin. The first-line treatment of gonorrhea in Malawi should be reassessed.
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Affiliation(s)
| | - Jane S Chen
- Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, USA
| | - Robert Krysiak
- UNC Project Malawi, Lilongwe, Malawi
- Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, USA
| | | | | | | | | | - Blessing Kamtambe
- Bwaila District Hospital, Lilongwe District Health Office, Lilongwe, Malawi
| | | | | | - Daniel Golparian
- WHO Collaborating Centre for Gonorrhoea and Other STIs, Örebro University Hospital and Örebro University, Örebro, Sweden
| | - Magnus Unemo
- WHO Collaborating Centre for Gonorrhoea and Other STIs, Örebro University Hospital and Örebro University, Örebro, Sweden
| | - Myron S Cohen
- Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, USA
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Marcia M Hobbs
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Irving F Hoffman
- Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, USA
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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6
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Morton B, Burr S, Chikaonda T, Nsomba E, Manda-Taylor L, Henrion MYR, Banda NP, Rylance J, Ferreira DM, Jambo K, Gordon SB. A feasibility study of controlled human infection with Streptococcus pneumoniae in Malawi. EBioMedicine 2021; 72:103579. [PMID: 34571365 PMCID: PMC8479630 DOI: 10.1016/j.ebiom.2021.103579] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 08/18/2021] [Accepted: 09/02/2021] [Indexed: 01/04/2023] Open
Abstract
Background Persistent carriage of pneumococcal vaccine serotypes has occurred after introduction of PCV13 vaccination in Africa but the mechanisms are unclear. We tested the feasibility of using a human pneumococcal challenge model in Malawi to understand immune correlates of protection against carriage and to trial alternative vaccine candidates. We aimed to identify a dose of Streptococcus pneumoniae serotype 6B sufficient to establish nasopharyngeal carriage in 40% of those nasally inoculated and evaluate nasal mucosal immunity before and after experimental inoculation. Methods Healthy student volunteers were recruited and inoculated with saline, 20,000 CFU/naris or 80,000 CFU/naris of Streptococcus pneumoniae serotype 6B Post inoculation carriage was determined by nasal sampling for bacterial culture and lytA PCR. Immunological responses were measured in serum and nasal mucosal biopsies before and after bacterial inoculation. Findings Twenty-four subjects completed the feasibility protocol with minimal side effects. pneumococcal carriage was established in 0/6, 3/9 and 4/9 subjects in the saline, 20,000 CFU/naris and 80,000 CFU/naris groups, respectively. Incidental (natural) serotype carriage was common (7/24 participants carried non-6B strains, 29.2%. Experimentally induced type 6B pneumococcal carriage was associated with pro-inflammatory nasal mucosal responses prior to inoculation and altered mucosal recruitment of immune cells post bacterial challenge. There was no association with serum anti-capsular antibody. Interpretation The serotype 6B experimental human pneumococcal carriage model is feasible in Malawi and can now be used to determine the immunological correlates of protection against carriage and vaccine efficacy in this population.
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Affiliation(s)
- Ben Morton
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, College of Medicine, P.O. Box 30096, Chichiri, Blantyre, Malawi; Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom; Liverpool University Hospitals NHS Foundation Trust Liverpool L9 7AL, United Kingdom; Queen Elizabeth Central Hospital, P.O. Box 95, Blantyre, Malawi.
| | - Sarah Burr
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, College of Medicine, P.O. Box 30096, Chichiri, Blantyre, Malawi; Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom
| | - Tarsizio Chikaonda
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, College of Medicine, P.O. Box 30096, Chichiri, Blantyre, Malawi.
| | - Edna Nsomba
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, College of Medicine, P.O. Box 30096, Chichiri, Blantyre, Malawi; Queen Elizabeth Central Hospital, P.O. Box 95, Blantyre, Malawi.
| | - Lucinda Manda-Taylor
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, College of Medicine, P.O. Box 30096, Chichiri, Blantyre, Malawi; College of Medicine, Private Bag 360, Chichiri, Blantyre, Malawi.
| | - Marc Y R Henrion
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, College of Medicine, P.O. Box 30096, Chichiri, Blantyre, Malawi; Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom.
| | - Ndaziona Peter Banda
- Queen Elizabeth Central Hospital, P.O. Box 95, Blantyre, Malawi; College of Medicine, Private Bag 360, Chichiri, Blantyre, Malawi
| | - Jamie Rylance
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, College of Medicine, P.O. Box 30096, Chichiri, Blantyre, Malawi; Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom; Queen Elizabeth Central Hospital, P.O. Box 95, Blantyre, Malawi.
| | - Daniela M Ferreira
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom.
| | - Kondwani Jambo
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, College of Medicine, P.O. Box 30096, Chichiri, Blantyre, Malawi; Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom.
| | - Stephen B Gordon
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, College of Medicine, P.O. Box 30096, Chichiri, Blantyre, Malawi; Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom; Queen Elizabeth Central Hospital, P.O. Box 95, Blantyre, Malawi.
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Morton B, Jambo K, Chikaonda T, Rylance J, Henrion MY, Banda NP, Nsomba E, Gondwe J, Ferreira D, Gordon SB. The influence of pneumococcal conjugate vaccine-13 on nasal colonisation in a controlled human infection model of pneumococcal carriage in Malawi: a double-blinded randomised controlled trial protocol. Wellcome Open Res 2021; 6:240. [PMID: 36263101 PMCID: PMC9549377.2 DOI: 10.12688/wellcomeopenres.17172.2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2022] [Indexed: 11/20/2022] Open
Abstract
Streptococcus pneumoniae is the leading cause of morbidity and mortality due to community acquired pneumonia, bacterial meningitis and bacteraemia worldwide. Pneumococcal conjugate vaccines protect against invasive disease, but are expensive to manufacture, limited in serotype coverage, associated with serotype replacement, and demonstrate reduced effectiveness against mucosal colonisation. For Malawi, nasopharyngeal carriage of vaccine-type pneumococci is common in vaccinated children despite national roll-out of 13-valent pneumococcal conjugate vaccine (PCV13) since 2011. Our team has safely transferred an established experimental human pneumococcal carriage method from Liverpool School of Tropical Medicine to the Malawi-Liverpool Wellcome Trust Clinical Research Programme, Malawi. This study will determine potential immunological mechanisms for the differential effects of PCV13 on nasal carriage between healthy Malawian and UK populations. We will conduct a double-blinded randomised controlled trial to vaccinate (1:1) participants with either PCV13 or control (normal saline). After a period of one month, participants will be inoculated with S. pneumoniae serotype 6B to experimentally induce nasal carriage using the EHPC method. Subsequently, participants will be invited for a second inoculation after one year to determine longer-term vaccine-induced immunological effects. Primary endpoint: detection of inoculated pneumococci by classical culture from nasal wash recovered from the participants after pneumococcal challenge. Secondary endpoints: local and systemic innate, humoral and cellular responses to PCV-13 with and without pneumococcal nasal carriage The primary objective of this controlled human infection model study is to determine if PCV-13 vaccination is protective against pneumococcal carriage in healthy adult Malawian volunteers. This study will help us to understand the observed differences in PCV-13 efficacy between populations and inform the design of future vaccines relevant to the Malawian population. Trial Registration: Pan African Clinical Trial Registry (REF: PACTR202008503507113).
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Affiliation(s)
- Ben Morton
- Lung Health, Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Critical Care Medicine, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
- Department of Medicine, Queen Elizabeth Central Hospital, Blantyre, Malawi
| | - Kondwani Jambo
- Lung Health, Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Tarsizio Chikaonda
- Lung Health, Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Jamie Rylance
- Lung Health, Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Department of Medicine, Queen Elizabeth Central Hospital, Blantyre, Malawi
| | - Marc Y.R. Henrion
- Lung Health, Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Ndaziona Peter Banda
- Department of Medicine, Queen Elizabeth Central Hospital, Blantyre, Malawi
- College of Medicine, Malawi, Blantyre, Malawi
| | - Edna Nsomba
- Lung Health, Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Department of Medicine, Queen Elizabeth Central Hospital, Blantyre, Malawi
| | - Joel Gondwe
- Lung Health, Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Daniela Ferreira
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Stephen B. Gordon
- Lung Health, Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Department of Medicine, Queen Elizabeth Central Hospital, Blantyre, Malawi
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Morton B, Jambo K, Chikaonda T, Rylance J, Henrion MY, Banda NP, Nsomba E, Gondwe J, Ferreira D, Gordon SB. The influence of pneumococcal conjugate vaccine-13 on nasal colonisation in a controlled human infection model of pneumococcal carriage in Malawi: a double-blinded randomised controlled trial protocol. Wellcome Open Res 2021; 6:240. [PMID: 36263101 PMCID: PMC9549377 DOI: 10.12688/wellcomeopenres.17172.1] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2021] [Indexed: 11/20/2022] Open
Abstract
Streptococcus pneumoniae is the leading cause of morbidity and mortality due to community acquired pneumonia, bacterial meningitis and bacteraemia worldwide. Pneumococcal conjugate vaccines protect against invasive disease, but are expensive to manufacture, limited in serotype coverage, associated with serotype replacement, and demonstrate reduced effectiveness against mucosal colonisation. For Malawi, nasopharyngeal carriage of vaccine-type pneumococci is common in vaccinated children despite national roll-out of 13-valent pneumococcal conjugate vaccine (PCV13) since 2011. Our team has safely transferred an established experimental human pneumococcal carriage method from Liverpool School of Tropical Medicine to the Malawi-Liverpool Wellcome Trust Clinical Research Programme, Malawi. This study will determine potential immunological mechanisms for the differential effects of PCV13 on nasal carriage between healthy Malawian and UK populations. We will conduct a double-blinded randomised controlled trial to vaccinate (1:1) participants with either PCV13 or control (normal saline). After a period of one month, participants will be inoculated with S. pneumoniae serotype 6B to experimentally induce nasal carriage using the EHPC method. Subsequently, participants will be invited for a second inoculation after one year to determine longer-term vaccine-induced immunological effects. Primary endpoint: detection of inoculated pneumococci by classical culture from nasal wash recovered from the participants after pneumococcal challenge. Secondary endpoints: local and systemic innate, humoral and cellular responses to PCV-13 with and without pneumococcal nasal carriage The primary objective of this controlled human infection model study is to determine if PCV-13 vaccination is protective against pneumococcal carriage in healthy adult Malawian volunteers. This study will help us to understand the observed differences in PCV-13 efficacy between populations and inform the design of future vaccines relevant to the Malawian population. Trial Registration: Pan African Clinical Trial Registry (REF: PACTR202008503507113).
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Affiliation(s)
- Ben Morton
- Lung Health, Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Critical Care Medicine, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
- Department of Medicine, Queen Elizabeth Central Hospital, Blantyre, Malawi
| | - Kondwani Jambo
- Lung Health, Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Tarsizio Chikaonda
- Lung Health, Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Jamie Rylance
- Lung Health, Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Department of Medicine, Queen Elizabeth Central Hospital, Blantyre, Malawi
| | - Marc Y.R. Henrion
- Lung Health, Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Ndaziona Peter Banda
- Department of Medicine, Queen Elizabeth Central Hospital, Blantyre, Malawi
- College of Medicine, Malawi, Blantyre, Malawi
| | - Edna Nsomba
- Lung Health, Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Department of Medicine, Queen Elizabeth Central Hospital, Blantyre, Malawi
| | - Joel Gondwe
- Lung Health, Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Daniela Ferreira
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Stephen B. Gordon
- Lung Health, Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Department of Medicine, Queen Elizabeth Central Hospital, Blantyre, Malawi
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Tegha G, Ciccone EJ, Krysiak R, Kaphatika J, Chikaonda T, Ndhlovu I, van Duin D, Hoffman I, Juliano JJ, Wang J. Genomic epidemiology of Escherichia coli isolates from a tertiary referral center in Lilongwe, Malawi. Microb Genom 2021; 7:mgen000490. [PMID: 33295867 PMCID: PMC8115906 DOI: 10.1099/mgen.0.000490] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 11/17/2020] [Indexed: 02/06/2023] Open
Abstract
Antimicrobial resistance (AMR) is a global threat, including in sub-Saharan Africa. However, little is known about the genetics of resistant bacteria in the region. In Malawi, there is growing concern about increasing rates of antimicrobial resistance to most empirically used antimicrobials. The highly drug resistant Escherichia coli sequence type (ST) 131, which is associated with the extended spectrum β-lactamase blaCTX-M-15, has been increasing in prevalence globally. Previous data from isolates collected between 2006 and 2013 in southern Malawi have revealed the presence of ST131 and the blaCTX-M-15 gene in the country. We performed whole genome sequencing (WGS) of 58 clinical E. coli isolates at Kamuzu Central Hospital, a tertiary care centre in central Malawi, collected from 2012 to 2018. We used Oxford Nanopore Technologies (ONT) sequencing, which was performed in Malawi. We show that ST131 is observed more often (14.9% increasing to 32.8%) and that the blaCTX-M-15 gene is occurring at a higher frequency (21.3% increasing to 44.8%). Phylogenetics indicates that isolates are highly related between the central and southern geographic regions and confirms that ST131 isolates are contained in a single group. All AMR genes, including blaCTX-M-15, were widely distributed across sequence types. We also identified an increased number of ST410 isolates, which in this study tend to carry a plasmid-located copy of blaCTX-M-15 gene at a higher frequency than blaCTX-M-15 occurs in ST131. This study confirms the expanding nature of ST131 and the wide distribution of the blaCTX-M-15 gene in Malawi. We also highlight the feasibility of conducting longitudinal genomic epidemiology studies of important bacteria with the sequencing done on site using a nanopore platform that requires minimal infrastructure.
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Affiliation(s)
| | - Emily J. Ciccone
- Division of Infectious Diseases, School of Medicine, University of North Carolina, USA
| | | | | | | | | | - David van Duin
- Division of Infectious Diseases, School of Medicine, University of North Carolina, USA
| | - Irving Hoffman
- Division of Infectious Diseases, School of Medicine, University of North Carolina, USA
| | - Jonathan J. Juliano
- Division of Infectious Diseases, School of Medicine, University of North Carolina, USA
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, USA
- Curriculum in Genetics and Molecular Biology, School of Medicine, University of North Carolina, USA
| | - Jeremy Wang
- Department of Genetics, School of Medicine, University of North Carolina, USA
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Chikaonda T, Nguluwe N, Barnett B, Gokhale RH, Krysiak R, Thengolose I, Rosenberg NE, Stanley C, Mpunga J, Hoffman IF, Hosseinipour M, Scott L, Stevens W. Performance of Xpert ® MTB/RIF among tuberculosis outpatients in Lilongwe, Malawi. Afr J Lab Med 2017; 6:464. [PMID: 28879160 PMCID: PMC5516918 DOI: 10.4102/ajlm.v6i2.464] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 10/13/2016] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Xpert® MTB/RIF is a molecular test for the detection of Mycobacterium tuberculosis and rifampicin resistance. It is considered to be a great advance over smear microscopy and culture. However, there is very little information regarding the performance characteristics of Xpert MTB/RIF in Malawi. OBJECTIVE We aimed to evaluate the performance of Xpert MTB/RIF in a Malawian setting. METHODS Stored sputum pellets were processed on Xpert MTB/RIF between June 2012 and May 2014. Results were compared to mycobacteria growth indicator tube and Löwenstein-Jensen cultures, LED fluorescent microscopy and GenoType® MTBDRplus assay. Rifampicin resistance was confirmed by DNA sequencing. RESULTS Of the 348 specimens with valid Xpert MTB/RIF results, 129/348 (37%) were smear-positive and 198/348 (57%) were culture-positive. Xpert MTB/RIF demonstrated a sensitivity of 93.8% (95% CI 89.4% - 96.8%) and specificity of 97.4% (95% CI 93.5% - 99.3%), with a positive predictive value of 97.8% (95% CI 94.6% - 99.4%) and a negative predictive value of 92.6% (95% CI 87.4% - 96.1%). Xpert MTB/RIF correctly identified 185/186 (99.5%) rifampicin-sensitive and 2/2 (100%) rifampicin-resistant M. tuberculosis strains. Mutations were not detected by sequencing in one isolate which was rifampicin resistant on Xpert MTB/RIF but sensitive on MTBDRplus. Four non-tuberculous mycobacteria grew from four smear-negative specimens, namely, M. avium (n = 1) and M. intracellulare (n = 3). No cross-reactivity was observed with any of the non-tuberculous mycobacteria when using Xpert MTB/RIF. CONCLUSION When fully implemented, Xpert MTB/RIF may have an impact on patient care in Malawi. The increased diagnostic yield of Xpert MTB/RIF over smear microscopy can increase laboratory-confirmed tuberculosis detection and ensure that treatment is given to appropriate individuals or groups.
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Affiliation(s)
- Tarsizio Chikaonda
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
- University of North Carolina Project, Lilongwe, Malawi
| | | | - Brian Barnett
- University of North Carolina Project, Lilongwe, Malawi
| | | | | | | | | | | | - James Mpunga
- Malawi National Tuberculosis Programme, Lilongwe, Malawi
| | - Irving F. Hoffman
- University of North Carolina Project, Lilongwe, Malawi
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Mina Hosseinipour
- University of North Carolina Project, Lilongwe, Malawi
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Lesley Scott
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Wendy Stevens
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
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Chikaonda T, Ketseoglou I, Nguluwe N, Krysiak R, Thengolose I, Nyakwawa F, Rosenberg NE, Stanley C, Mpunga J, Hoffman IF, Papathanasopoulos MA, Hosseinipour M, Scott L, Stevens W. Molecular characterisation of rifampicin-resistant Mycobacterium tuberculosis strains from Malawi. Afr J Lab Med 2017; 6:463. [PMID: 28879159 PMCID: PMC5523914 DOI: 10.4102/ajlm.v6i2.463] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 10/05/2016] [Indexed: 12/02/2022] Open
Abstract
Background Availability and access to the detection of resistance to anti-tuberculosis drugs remains a significant challenge in Malawi due to limited diagnostic services. The Xpert® MTB/RIF can detect Mycobacterium tuberculosis and resistance to rifampicin in a single, rapid assay. Rifampicin-resistant M. tuberculosis has not been well studied in Malawi. Objectives We aimed to determine mutations in the rifampicin resistance determining region (RRDR) of the rpoB gene of M. tuberculosis strains which were defined as resistant to rifampicin by the Xpert MTB/RIF assay. Methods Rifampicin-resistant isolates from 43 adult patients (≥ 18 years) from various districts of Malawi were characterised for mutations in the RRDR (codons 507–533) of the rpoB gene by DNA sequencing. Results Mutations were found in 37/43 (86%) of the resistant isolates in codons 511, 512, 513, 516, 522, 526 and 531. The most common mutations were in codons 526 (38%), 531 (29.7%) and 516 (16.2%). Mutations were not found in 6/43 (14%) of the resistant isolates. No novel rpoB mutations other than those previously described were found among the rifampicin-resistant M. tuberculosis complex strains. Conclusion This study is the first to characterise rifampicin resistance in Malawi. The chain-termination DNA sequencing employed in this study is a standard method for the determination of nucleotide sequences and can be used to confirm rifampicin resistance obtained using other assays, including the Xpert MTB/RIF. Further molecular cluster analysis, such as spoligotyping and DNA finger printing, is still required to determine transmission dynamics and the epidemiological link of the mutated strains.
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Affiliation(s)
- Tarsizio Chikaonda
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa.,UNC Project, Lilongwe, Malawi
| | - Irene Ketseoglou
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | | | | | | | - Felix Nyakwawa
- Malawi National Tuberculosis Programme, Lilongwe, Malawi
| | | | | | - James Mpunga
- Malawi National Tuberculosis Programme, Lilongwe, Malawi
| | - Irving F Hoffman
- UNC Project, Lilongwe, Malawi.,University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Maria A Papathanasopoulos
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Mina Hosseinipour
- UNC Project, Lilongwe, Malawi.,University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Lesley Scott
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Wendy Stevens
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
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Zungu LI, Magombo T, Chikaonda T, Thomas R, Mwenda R, Kandulu J, Chilima B, Chiwaula M, Mbene A, Saka E. A national quality assurance programme for point-of-care testing in Malawi. Afr J Lab Med 2016; 5:540. [PMID: 28879130 PMCID: PMC5433829 DOI: 10.4102/ajlm.v5i2.540] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 08/11/2016] [Indexed: 11/09/2022] Open
Affiliation(s)
- Lutho I Zungu
- Ministry of Health Directorate of Health Technical services - Diagnostics, Lilongwe, Malawi
| | | | - Tarsizio Chikaonda
- University of North Carolina (UNC) HIV/AIDS Research Project Laboratory, Lilongwe, Malawi
| | | | - Reuben Mwenda
- Ministry of Health Directorate of Health Technical services - Diagnostics, Lilongwe, Malawi
| | - James Kandulu
- Ministry of Health Directorate of Health Technical services - Diagnostics, Lilongwe, Malawi
| | - Benson Chilima
- National Reference Laboratories, Community Health Sciences Unit (CHSU), Lilongwe, Malawi
| | - Mavuto Chiwaula
- National Reference Laboratories, Community Health Sciences Unit (CHSU), Lilongwe, Malawi
| | - Alwin Mbene
- Northern Health Zone, Ministry of Health, Lilongwe, Malawi
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13
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Barnett B, Gokhale RH, Krysiak R, Kanyemba C, Chikaonda T, Bokosi M, Mukuzunga C, Saidi F, Phiri S, Hoffman IF, Hosseinipour MC. Prevalence of drug resistant TB among outpatients at an HIV/TB clinic in Lilongwe, Malawi. Trans R Soc Trop Med Hyg 2016; 109:763-8. [PMID: 26626340 DOI: 10.1093/trstmh/trv092] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND We sought to determine the prevalence of drug resistant TB among outpatients initiating TB treatment in Lilongwe, Malawi. METHODS This was a prospective cohort study of patients 18 years and older initiating TB treatment at Martin Preuss Centre, the primary integrated HIV/TB clinic in Lilongwe, Malawi, from April 2011 to July 2012. Procedures included questionnaires, physical exam, chest x-ray, full blood count and sputum collection. Sputum samples underwent acid-fast bacilli (AFB) smear testing and culture by Lowenstein-Jensen (LJ) and liquid Mycobacteria Growth Indicator Tube (MGIT) methods. Drug sensitivity was investigated using the Hain GenoType MTBDRplus line probe assay. RESULTS Of the 702 patients, 219 (31.2%) were female and 653 (93.0%) were presenting for first-time TB treatment. HIV co-infection was present in 420 (59.8%) cases, with 137 (32.6%) of those patients receiving antiretroviral therapy at presentation. TB was culture-confirmed in 375 (53.4%) patients, 349 of which were first time treatment and 26 retreatment. Ten cases of isoniazid-resistant TB (2.9% of culture confirmed cases of newly treated TB), one of rifampin-resistant TB (0.3% culture confirmed cases of newly treated TB) and one of multi-drug resistant TB (MDR-TB) (3.8% of culture confirmed cases of retreatment TB) were detected. CONCLUSIONS MDR-TB prevalence is low among outpatients initiating TB treatment in Lilongwe.
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Affiliation(s)
- Brian Barnett
- University of North Carolina Project, Lilongwe, Malawi Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | | | | | | | | | | | | | - Friday Saidi
- University of North Carolina Project, Lilongwe, Malawi
| | - Sam Phiri
- Light House Clinic Trust, Lilongwe, Malawi
| | - Irving F Hoffman
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Mina C Hosseinipour
- University of North Carolina Project, Lilongwe, Malawi Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
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Vorkas C, Kayira D, van der Horst C, Hoffman I, Hosseinipour M, Kanyemba C, Nguluwe N, Chikaonda T, Kalikhoka M, Kalaundi D, Namarika D, Gilligan P, Krysiak R. Tuberculosis drug resistance and outcomes among tuberculosis inpatients in Lilongwe, Malawi. Malawi Med J 2012; 24:21-24. [PMID: 23638265 PMCID: PMC3588213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023] Open
Abstract
UNLABELLED SETTING/OBJECTIVE: We evaluated clinical characteristics, yield of solid vs. liquid culture, polymerase chain reaction (PCR)-based drug-resistance profiles, and clinical outcomes of tuberculosis (TB) inpatients in Lilongwe, Malawi. DESIGN We enrolled adult patients admitted to the Bwaila TB Ward from Jan-Aug/2010. Evaluations included questionnaires, clinical exam, chest radiograph, HIV status, CD4 lymphocyte count, plasma HIVRNA and sputum analysis including Auramine-O stain, Lowenstein-Jensen (LJ) and Mycobacterial Growth Indicator Tube (MGIT) culture, and susceptibility testing using the HAIN GenoType® MTBDRplus. RESULTS Eighty-eight patients were enrolled (88% re-treatment, 42% smear positive, 93% pulmonary TB, 74% HIV co-infected). At baseline, 44/88 (50%) MGIT and 28 (32%) LJ cultures were positive with a mean time to positivity of 12.1 (Range 1-42) and 21.5 (Range 7-58) days, respectively. Four percent (3/77) of retreatment patients or 8% of the 38 MGIT+ PCR-confirmed retreatment cases had multi-drug resistant tuberculosis (MDR TB). One MDR TB patient was smear negative and only one MDR patient was identified with LJ. Lower mean hemoglobin at admission was associated with mortality (10.5 vs. 7.5; p<0.01; CI 101 9.8-11.0). CONCLUSIONS The MDR TB burden among the retreatment population in Lilongwe, Malawi is similar to regional estimates by the WHO (7.7% 95% CI 0-18.1). MDR TB patients are not routinely identified with sputum smear or LJ, suggesting more efficient technology should be adopted.
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Affiliation(s)
- Charles Vorkas
- University of North Carolina Hospitals Department of Medicine
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15
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Hartung TK, Chimbayo D, van Oosterhout JJG, Chikaonda T, van Doornum GJJ, Claas ECJ, Melchers WJG, Molyneux ME, Zijlstra EE. Etiology of suspected pneumonia in adults admitted to a high-dependency unit in Blantyre, Malawi. Am J Trop Med Hyg 2011; 85:105-12. [PMID: 21734133 PMCID: PMC3122352 DOI: 10.4269/ajtmh.2011.10-0640] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 02/14/2011] [Indexed: 11/07/2022] Open
Abstract
The microbiologic etiology of severe pneumonia in hospitalized patients is rarely known in sub-Saharan Africa. Through a comprehensive diagnostic work-up, we aimed to identify the causative agent in severely ill patients with a clinical picture of pneumonia admitted to a high-dependency unit. A final diagnosis was made and categorized as confirmed or probable by using predefined criteria. Fifty-one patients were recruited (45% females), with a mean age of 35 years (range = 17-88 years), of whom 11(22%) died. Forty-eight (94%) of the patients were seropositive for human immunodeficiency virus; 14 (29%) of these patients were receiving antiretroviral treatment. Final diagnoses were bacterial pneumonia (29%), Pneumocystis jirovecii pneumonia (27%), pulmonary tuberculosis (22%), and pulmonary Kaposi's sarcoma (16%); 39 (77%) of these cases were confirmed cases. Fifteen (29%) patients had multiple isolates. At least 3 of 11 viral-positive polymerase chain reaction (PCR) results of bronchoalveolar lavage fluid were attributed clinical relevance. No atypical bacterial organisms were found.
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Affiliation(s)
- Thomas K Hartung
- Department of Medicine, College of Medicine, University of Malawi, Blantyre, Malawi; Department of Respiratory Medicine, Victoria Hospital, Kirkcaldy, United Kingdom. [corrected]
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Bell DJ, Dacombe R, Graham SM, Hicks A, Cohen D, Chikaonda T, French N, Molyneux ME, Zijlstra EE, Squire SB, Gordon SB. Simple measures are as effective as invasive techniques in the diagnosis of pulmonary tuberculosis in Malawi. Int J Tuberc Lung Dis 2009; 13:99-104. [PMID: 19105886 PMCID: PMC2873674] [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] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
SETTING Detection of smear-positive pulmonary tuberculosis (PTB) cases is vital for tuberculosis (TB) control. Methods to augment sputum collection are available, but their additional benefit is uncertain in resource-limited settings. OBJECTIVE To compare the diagnostic yields using five methods to obtain sputum from adults diagnosed with smear-negative PTB in Malawi. DESIGN Self-expectorated sputum was collected under supervision for microscopy and mycobacterial culture in the study laboratory. Confirmed smear-negative patients provided physiotherapy-assisted sputum and induced sputum, followed the next morning by gastric washing and bronchoalveolar lavage (BAL) samples. RESULTS A total of 150 patients diagnosed with smear-negative PTB by the hospital service were screened; 39 (26%) were smear-positive from supervised self-expectorated sputum examined in the study laboratory. The remaining 111 confirmed smear-negative patients were enrolled in the study; 89% were human immunodeficiency virus positive. Seven additional smear-positive cases were diagnosed using the augmented sputum collection techniques. No differences were observed in the numbers of cases detected using the different methods. Of the 46 smear-positive cases, 44 (95.6%) could be detected from self-expectorated and physiotherapy-assisted samples. CONCLUSIONS For countries such as Malawi, the best use of limited resources to detect smear-positive PTB cases would be to improve the quality of self-expectorated sputum collection and microscopy. The additional diagnostic yield using BAL after induced sputum is limited.
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Affiliation(s)
- D J Bell
- Tropical and Infectious Diseases Unit, Royal Liverpool University Hospital, Liverpool, UK.
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