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Allali I, Abotsi RE, Tow LA, Thabane L, Zar HJ, Mulder NM, Nicol MP. Human microbiota research in Africa: a systematic review reveals gaps and priorities for future research. MICROBIOME 2021; 9:241. [PMID: 34911583 PMCID: PMC8672519 DOI: 10.1186/s40168-021-01195-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 11/14/2021] [Indexed: 05/11/2023]
Abstract
BACKGROUND The role of the human microbiome in health and disease is an emerging and important area of research; however, there is a concern that African populations are under-represented in human microbiome studies. We, therefore, conducted a systematic survey of African human microbiome studies to provide an overview and identify research gaps. Our secondary objectives were: (i) to determine the number of peer-reviewed publications; (ii) to identify the extent to which the researches focused on diseases identified by the World Health Organization [WHO] State of Health in the African Region Report as being the leading causes of morbidity and mortality in 2018; (iii) to describe the extent and pattern of collaborations between researchers in Africa and the rest of the world; and (iv) to identify leadership and funders of the studies. METHODOLOGY We systematically searched Medline via PubMed, Scopus, CINAHL, Academic Search Premier, Africa-Wide Information through EBSCOhost, and Web of Science from inception through to 1st April 2020. We included studies that characterized samples from African populations using next-generation sequencing approaches. Two reviewers independently conducted the literature search, title and abstract, and full-text screening, as well as data extraction. RESULTS We included 168 studies out of 5515 records retrieved. Most studies were published in PLoS One (13%; 22/168), and samples were collected from 33 of the 54 African countries. The country where most studies were conducted was South Africa (27/168), followed by Kenya (23/168) and Uganda (18/168). 26.8% (45/168) focused on diseases of significant public health concern in Africa. Collaboration between scientists from the United States of America and Africa was most common (96/168). The first and/or last authors of 79.8% of studies were not affiliated with institutions in Africa. Major funders were the United States of America National Institutes of Health (45.2%; 76/168), Bill and Melinda Gates Foundation (17.8%; 30/168), and the European Union (11.9%; 20/168). CONCLUSIONS There are significant gaps in microbiome research in Africa, especially those focusing on diseases of public health importance. There is a need for local leadership, capacity building, intra-continental collaboration, and national government investment in microbiome research within Africa. Video Abstract.
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Affiliation(s)
- Imane Allali
- Computational Biology Division, Department of Integrative Biomedical Sciences, University of Cape Town, Cape Town, South Africa
- Laboratory of Human Pathologies Biology, Department of Biology, Faculty of Sciences, and Genomic Centre of Human Pathologies, Faculty of Medicine and Pharmacy, Mohammed V University in Rabat, Rabat, Morocco
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Regina E Abotsi
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Department of Molecular and Cell Biology, Faculty of Science, University of Cape Town, Cape Town, South Africa
- Department of Pharmaceutical Microbiology, School of Pharmacy, University of Health and Allied Sciences, Ho, Ghana
| | - Lemese Ah Tow
- Division of Medical Microbiology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Lehana Thabane
- Department of Health Research Methods, Evidence and Impact, McMaster University, Hamilton, Ontario, Canada
- Biostatistics Unit, Father Sean O'Sullivan Research Centre, St Joseph's Healthcare, Hamilton, Ontario, Canada
- Departments of Paediatrics and Anaesthesia, McMaster University, Hamilton, Ontario, Canada
- Centre for Evaluation of Medicine, St Joseph's Healthcare, Hamilton, Ontario, Canada
- Population Health Research Institute, Hamilton Health Sciences, Hamilton, Ontario, Canada
- Centre for Evidence-based Health Care, Faculty of Health Sciences, Stellenbosch University, Tygerberg, South Africa
- Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Heather J Zar
- Department of Paediatrics and Child Health, Red Cross War Memorial Children's Hospital, Cape Town, South Africa
- MRC Unit on Child & Adolescent Health, University of Cape Town, Cape Town, South Africa
| | - Nicola M Mulder
- Computational Biology Division, Department of Integrative Biomedical Sciences, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Mark P Nicol
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
- Division of Medical Microbiology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
- School of Biomedical Sciences, University of Western Australia, M504, Perth, WA, 6009, Australia.
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Onywera H, Williamson AL, Ponomarenko J, Meiring TL. The Penile Microbiota in Uncircumcised and Circumcised Men: Relationships With HIV and Human Papillomavirus Infections and Cervicovaginal Microbiota. Front Med (Lausanne) 2020; 7:383. [PMID: 32850898 PMCID: PMC7406686 DOI: 10.3389/fmed.2020.00383] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Accepted: 06/19/2020] [Indexed: 12/14/2022] Open
Abstract
While the human microbiota especially that of the gut, cervix, and vagina continue to receive great attention, very little is currently known about the penile (glans, coronal sulcus, foreskin, and shaft) microbiota. The best evidences to date for the potential role of the penile microbiota in human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs) acquisition have come from studies examining medical male circumcision. We are still at the foothills of identifying specific penile bacteria that could be associated with increased risk of STI/HIV acquisition. In this review, we summarize the available literature on the human penile microbiota and how it is impacted by circumcision. We also discuss the potential role of penile microbiota in STIs and its impact on cervicovaginal microbiota. Taken together, the findings from the penile microbiota studies coupled with observational studies on the effect of male circumcision for reduction of STI/HIV infection risk suggest that specific penile anaerobic bacteria such as Prevotella spp. potentially have a mechanistic role that increases the risk of genital infections and syndromes, including bacterial vaginosis in sexual partners. Although penile Corynebacterium and Staphylococcus have been associated with healthy cervicovaginal microbiota and have been found to increase following male circumcision, further investigations are warranted to ascertain the exact roles of these bacteria in the reproductive health of men and women. This review aims to address existing gaps and challenges and future prospects in the penile microbiota research. The information described here may have translational significance, thereby improving reproductive health and management of STI/HIV.
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Affiliation(s)
- Harris Onywera
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa.,Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.,Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Anna-Lise Williamson
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa.,Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.,SAMRC Gynaecological Cancer Research Centre, University of Cape Town, Cape Town, South Africa
| | - Julia Ponomarenko
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain.,University of Pompeu Fabra, Barcelona, Spain
| | - Tracy L Meiring
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa.,Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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Onywera H, Williamson AL, Cozzuto L, Bonnin S, Mbulawa ZZA, Coetzee D, Ponomarenko J, Meiring TL. The penile microbiota of Black South African men: relationship with human papillomavirus and HIV infection. BMC Microbiol 2020; 20:78. [PMID: 32252632 PMCID: PMC7137192 DOI: 10.1186/s12866-020-01759-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 03/20/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND To date, the microbiota of the human penis has been studied mostly in connection with circumcision, HIV risk and female partner bacterial vaginosis (BV). These studies have shown that male circumcision reduces penile anaerobic bacteria, that greater abundance of penile anaerobic bacteria is correlated with increased cytokine levels and greater risk of HIV infection, and that the penile microbiota is an important harbour for BV-associated bacteria. While circumcision has been shown to significantly reduce the risk of acquiring human papillomavirus (HPV) infection, the relationship of the penile microbiota with HPV is still unknown. In this study, we examined the penile microbiota of HPV-infected men as well as the impact of HIV status. RESULTS The penile skin microbiota of 238 men from Cape Town (South Africa) were profiled using Illumina sequencing of the V3-V4 hypervariable regions of the 16S rRNA gene. Corynebacterium and Prevotella were found to be the most abundant genera. Six distinct community state types (CSTs) were identified. CST-1, dominated by Corynebacterium, corresponded to less infections with high-risk HPV (HR-HPV) relative to CSTs 2-6. Men in CST-5 had greater relative abundances of Prevotella, Clostridiales, and Porphyromonas and a lower relative abundance of Corynebacterium. Moreover, they were significantly more likely to have HPV or HR-HPV infections than men in CST-1. Using a machine learning approach, we identified greater relative abundances of the anaerobic BV-associated bacteria (Prevotella, Peptinophilus, and Dialister) and lower relative abundance of Corynebacterium in HR-HPV-infected men compared to HR-HPV-uninfected men. No association was observed between HIV and CST, although the penile microbiota of HIV-infected men had greater relative abundances of Staphylococcus compared to HIV-uninfected men. CONCLUSIONS We found significant differences in the penile microbiota composition of men with and without HPV and HIV infections. HIV and HR-HPV infections were strongly associated with greater relative abundances of Staphylococcus and BV-associated bacterial taxa (notably Prevotella, Peptinophilus and Dialister), respectively. It is possible that these taxa could increase susceptibility to HIV and HR-HPV acquisition, in addition to creating conditions in which infections persist. Further longitudinal studies are required to establish causal relationships and to determine the extent of the effect.
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Affiliation(s)
- Harris Onywera
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Anna-Lise Williamson
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- SAMRC Gynaecological Cancer Research Centre, University of Cape Town, Cape Town, South Africa
| | - Luca Cozzuto
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Sarah Bonnin
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Zizipho Z A Mbulawa
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- SAMRC Gynaecological Cancer Research Centre, University of Cape Town, Cape Town, South Africa
- Department of Laboratory Medicine and Pathology, National Health Laboratory Service and Walter Sisulu University, Nelson Mandela Academic Hospital, Fort Gale, Mthatha, South Africa
| | - David Coetzee
- Center for Infectious Disease Epidemiology and Research, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
| | - Julia Ponomarenko
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- University of Pompeu Fabra, Barcelona, Spain
| | - Tracy L Meiring
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa.
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
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Gray RH. Male Circumcision for HIV and STI Prevention: A Reflection. Clin Chem 2019; 65:15-18. [PMID: 30602469 DOI: 10.1373/clinchem.2018.286542] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 09/26/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Ronald H Gray
- Department of Epidemiology, Johns Hopkins University, Bloomberg School of Public Health, Baltimore, MD.
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Liu CM, Tobian AAR, Gray RH. Ockham's Razor and the PrePex Male Circumcision Device. J Infect Dis 2016; 214:1126. [PMID: 27402777 DOI: 10.1093/infdis/jiw277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Accepted: 06/20/2016] [Indexed: 11/13/2022] Open
Affiliation(s)
- Cindy M Liu
- Department of Environmental and Occupational Health, Milken Institute School of Public Health, George Washington University, Washington D.C. Department of Medicine
| | - Aaron A R Tobian
- Department of Pathology, Johns Hopkins School of Medicine Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Ronald H Gray
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland Rakai Health Sciences Program, Entebbe, Uganda
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Brook I. Genital Anaerobic Bacterial Overgrowth and the PrePex Male Circumcision Device, Rakai, Uganda. J Infect Dis 2016; 214:1125-6. [PMID: 27402778 DOI: 10.1093/infdis/jiw276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 06/20/2016] [Indexed: 11/15/2022] Open
Affiliation(s)
- Itzhak Brook
- Departments of Pediatrics and Medicine, Georgetown University School of Medicine, Washington D.C
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