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Isolation and Genomic Analysis of an Intracellular Mycobacterium gordonae from a Free-Living
Acanthamoeba
sp. in a Hospital Environment in Lima, Peru. Microbiol Resour Announc 2022; 11:e0078422. [PMID: 36250863 PMCID: PMC9670939 DOI: 10.1128/mra.00784-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mycobacterium gordonae is a nontuberculous mycobacterium found in diverse environments and is considered an opportunistic pathogen in immunocompromised patients. We report the draft genome sequence of a Mycobacterium gordonae strain isolated from a free-living amoeba found in a nosocomial environment in Lima, Peru.
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Receveur JP, Bauer A, Pechal JL, Picq S, Dogbe M, Jordan HR, Rakestraw AW, Fast K, Sandel M, Chevillon C, Guégan JF, Wallace JR, Benbow ME. A need for null models in understanding disease transmission: the example of Mycobacterium ulcerans (Buruli ulcer disease). FEMS Microbiol Rev 2022; 46:fuab045. [PMID: 34468735 PMCID: PMC8767449 DOI: 10.1093/femsre/fuab045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 08/12/2021] [Indexed: 01/19/2023] Open
Abstract
Understanding the interactions of ecosystems, humans and pathogens is important for disease risk estimation. This is particularly true for neglected and newly emerging diseases where modes and efficiencies of transmission leading to epidemics are not well understood. Using a model for other emerging diseases, the neglected tropical skin disease Buruli ulcer (BU), we systematically review the literature on transmission of the etiologic agent, Mycobacterium ulcerans (MU), within a One Health/EcoHealth framework and against Hill's nine criteria and Koch's postulates for making strong inference in disease systems. Using this strong inference approach, we advocate a null hypothesis for MU transmission and other understudied disease systems. The null should be tested against alternative vector or host roles in pathogen transmission to better inform disease management. We propose a re-evaluation of what is necessary to identify and confirm hosts, reservoirs and vectors associated with environmental pathogen replication, dispersal and transmission; critically review alternative environmental sources of MU that may be important for transmission, including invertebrate and vertebrate species, plants and biofilms on aquatic substrates; and conclude with placing BU within the context of other neglected and emerging infectious diseases with intricate ecological relationships that lead to disease in humans, wildlife and domestic animals.
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Affiliation(s)
- Joseph P Receveur
- Department of Entomology, Michigan State University, East Lansing, MI 48824, USA
| | - Alexandra Bauer
- Department of Entomology, Michigan State University, East Lansing, MI 48824, USA
| | - Jennifer L Pechal
- Department of Entomology, Michigan State University, East Lansing, MI 48824, USA
| | - Sophie Picq
- Department of Entomology, Michigan State University, East Lansing, MI 48824, USA
| | - Magdalene Dogbe
- Department of Biological Sciences, Mississippi State University, Starkville, MS, USA
| | - Heather R Jordan
- Department of Biological Sciences, Mississippi State University, Starkville, MS, USA
| | - Alex W Rakestraw
- Department of Biological and Environmental Sciences, The University of West Alabama, Livingston, AL, USA
| | - Kayla Fast
- Department of Biological and Environmental Sciences, The University of West Alabama, Livingston, AL, USA
| | - Michael Sandel
- Department of Biological and Environmental Sciences, The University of West Alabama, Livingston, AL, USA
| | - Christine Chevillon
- Maladies Infectieuses et Vecteurs : Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), Université de Montpellier (UM), Centre National de la Recherche Scientifique (CNRS), Institut pour la Recherche et le Développement, Montpellier, France
| | - Jean-François Guégan
- Maladies Infectieuses et Vecteurs : Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), Université de Montpellier (UM), Centre National de la Recherche Scientifique (CNRS), Institut pour la Recherche et le Développement, Montpellier, France
- UMR Animal, santé, territoires, risques et écosystèmes, Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE), Centre de coopération internationale en recherche agronomique pour le développement (Cirad), Université de Montpellier (UM), Montpellier, France
| | - John R Wallace
- Department of Biology, Millersville University, Millersville, PA, USA
| | - M Eric Benbow
- Department of Entomology, Michigan State University, East Lansing, MI 48824, USA
- Ecology, Evolution and Behavior Program, Michigan State University, East Lansing, MI, USA
- AgBioResearch, Michigan State University, East Lansing, MI, USA
- Department of Osteopathic Medical Specialties, Michigan State University, East Lansing, MI, USA
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3
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Linking the Mycobacterium ulcerans environment to Buruli ulcer disease: Progress and challenges. One Health 2021; 13:100311. [PMID: 34485670 PMCID: PMC8403752 DOI: 10.1016/j.onehlt.2021.100311] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/10/2021] [Accepted: 08/13/2021] [Indexed: 11/21/2022] Open
Abstract
Buruli ulcer (BU), the second most common mycobacterial disease in West Africa, is a necrotizing skin disease that can lead to high morbidity in affected patients. The disease is caused by Mycobacterium ulcerans (MU), whose major virulence factor is mycolactone. Although early infection can be treated with antibiotics, an effective preventative strategy is challenging due to unknown reservoir(s) and unresolved mode(s) of transmission. Further, disease occurrence in remote locations with limited access to health facilities further complicates disease burden and associated costs. We discuss here MU transmission hypotheses and investigations into environmental reservoirs and discuss successes and challenges of studying MU and Buruli ulcer across human, animal, and environmental interfaces. We argue that a One Health approach is needed to advance the understanding of MU transmission and designing management scenarios that prevent and respond to epidemics. Although previous work has provided significant insights into risk factors, epidemiology and clinical perspectives of disease, understanding the bacterial ecology, environmental niches and role of mycolactone in natural environments and during infection of the human host remains equally important to better understanding and preventing this mysterious disease.
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Muleta AJ, Lappan R, Stinear TP, Greening C. Understanding the transmission of Mycobacterium ulcerans: A step towards controlling Buruli ulcer. PLoS Negl Trop Dis 2021; 15:e0009678. [PMID: 34437549 PMCID: PMC8389476 DOI: 10.1371/journal.pntd.0009678] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Mycobacterium ulcerans is the causative agent of Buruli ulcer, a rare but chronic debilitating skin and soft tissue disease found predominantly in West Africa and Southeast Australia. While a moderate body of research has examined the distribution of M. ulcerans, the specific route(s) of transmission of this bacterium remain unknown, hindering control efforts. M. ulcerans is considered an environmental pathogen given it is associated with lentic ecosystems and human-to-human spread is negligible. However, the pathogen is also carried by various mammals and invertebrates, which may serve as key reservoirs and mechanical vectors, respectively. Here, we examine and review recent evidence from these endemic regions on potential transmission pathways, noting differences in findings between Africa and Australia, and summarising the risk and protective factors associated with Buruli ulcer transmission. We also discuss evidence suggesting that environmental disturbance and human population changes precede outbreaks. We note five key research priorities, including adoption of One Health frameworks, to resolve transmission pathways and inform control strategies to reduce the spread of Buruli ulcer. Buruli ulcer is a debilitating skin and soft tissue disease characterised by large ulcerative wounds that are treated with antibiotics or with adjunctive surgery for advanced cases. Found predominantly in West Africa and Southeast Australia, the causative agent is the environmental bacterial pathogen Mycobacterium ulcerans. Lack of understanding of transmission pathways, combined with the absence of a vaccine, has hindered efforts to control the spread of M. ulcerans. Here, in order to identify probable transmission pathways and inform future studies, we review literature linking M. ulcerans to environmental reservoirs, mammalian hosts, and potential invertebrate vectors. We also summarise factors and behaviours that reduce the risk of developing Buruli ulcer, to inform effective prevention strategies and further shed light on transmission pathways.
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Affiliation(s)
- Anthony J. Muleta
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Rachael Lappan
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Timothy P. Stinear
- Department of Microbiology and Immunology, Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Australia
| | - Chris Greening
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Centre to Impact AMR, Monash University, Melbourne, Australia
- * E-mail:
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5
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The role of Acanthamoeba spp. in biofilm communities: a systematic review. Parasitol Res 2021; 120:2717-2729. [PMID: 34292376 DOI: 10.1007/s00436-021-07240-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 07/01/2021] [Indexed: 12/16/2022]
Abstract
Acanthamoeba spp. have always caused disease in immunosuppressed patients, but since 1986, they have become a worldwide public health issue by causing infection in healthy contact lens wearers. Amoebae of the Acanthamoeba genus are broadly distributed in nature, living either freely or as parasites, and are frequently associated with biofilms throughout the environment. These biofilms provide the parasite with protection against external aggression, thus favoring its increased pathogeny. This review aims to assess observational studies on the association between Acanthamoeba spp. and biofilms, opening potential lines of research on this severe ocular infection. A systematic literature search was conducted in May 2020 in the following databases: PubMed Central®/Medline, LILACS, The Cochrane Library, and EMBASE®. The studies were selected following the inclusion and exclusion criteria specifically defined for this review. Electronic research recovered 353 publications in the literature. However, none of the studies met the inclusion criterion of biofilm-producing Acanthamoeba spp., inferring that the parasite does not produce biofilms. Nonetheless, 78 studies were classified as potentially included regarding any association of Acanthamoeba spp. and biofilms. These studies were allocated across six different locations (hospital, aquatic, ophthalmic and dental environments, biofilms produced by bacteria, and other places). Acanthamoeba species use biofilms produced by other microorganisms for their benefit, in addition to them providing protection to and facilitating the dissemination of pathogens residing in them.
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Cano J, Rodríguez A, Simpson H, Tabah EN, Gómez JF, Pullan RL. Modelling the spatial distribution of aquatic insects (Order Hemiptera) potentially involved in the transmission of Mycobacterium ulcerans in Africa. Parasit Vectors 2018; 11:501. [PMID: 30189883 PMCID: PMC6127916 DOI: 10.1186/s13071-018-3066-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 08/17/2018] [Indexed: 11/10/2022] Open
Abstract
Background Biting aquatic insects belonging to the order Hemiptera have been suggested as potential vectors of Mycobacterium ulcerans in endemic areas for Buruli ulcer (BU). If this is the case, these insects would be expected to co-exist with M. ulcerans in the same geographical areas. Here, we studied the geographical distribution of six aquatic Hemiptera families that are thought to be vectors of M. ulcerans and explored their potential geographical overlapping with communities reporting BU cases in endemic countries. Methods We have developed ensemble ecological models of predicted distribution for six families of the Hemiptera (Naucoridae, Belostomatidae, Notonectidae, Nepidae, Corixidae and Gerridae) applying a robust modelling framework over a collection of recorded presences and a suite of environmental and topographical factors. Ecological niche factor analysis (ENFA) was first used to identify factors that best described the ecological niches for each hemipteran family. Finally, we explored the potential geographical co-occurrence of these insects and BU in two endemic countries, Cameroon and Ghana. Results Species of the families Naucoridae and Belostomatidae, according to our models, are widely distributed across Africa, although absent from drier and hotter areas. The other two families of biting Hemiptera, the Notonectidae and Nepidae, would have a more restricted distribution, being more predominant in western and southern Africa. All these four families of biting water bugs are widely distributed across coastal areas of West Africa. They would thrive in areas where annual mean temperature varies between 15–22 °C, with moderate annual precipitation (i.e. 350–1000 mm/annual) and near to water courses. Species of all hemipteran families show preference for human-made environments such as agricultural landscapes and urbanized areas. Finally, our analysis suggests that M. ulcerans and species of these aquatic insects might coexist in the same ecological niches, although there would be variation in species diversity between BU endemic areas. Conclusions Our findings predict the geographical co-existence of some species of aquatic hemipteran families and BU. Considering the existing biological evidence that points to some of these aquatic insects as potential phoretic vectors of M. ulcerans, its presence in BU endemic areas should be considered a risk factor. The ecological models here presented may be helpful to inform future environmental based models intended to delineate the potential geographical distribution of BU in the African region. Electronic supplementary material The online version of this article (10.1186/s13071-018-3066-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jorge Cano
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
| | - Antonio Rodríguez
- Department of Horticulture, Botany and Landscaping, School of Agriculture, Food and Forestry Science and Engineering, University of Lleida, Lleida, Spain
| | - Hope Simpson
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Earnest N Tabah
- National Yaws, Leishmaniasis, Leprosy and Buruli ulcer Control Programme, Ministry of Public Health, Yaounde, Cameroon
| | - Jose F Gómez
- Department of Biodiversity, Ecology & Evolution, Complutense University, Madrid, Spain
| | - Rachel L Pullan
- Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
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7
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Abstract
Nontuberculous mycobacteria (NTM) include species that colonize human epithelia, as well as species that are ubiquitous in soil and aquatic environments. NTM that primarily inhabit soil and aquatic environments include the Mycobacterium avium complex (MAC, M. avium and Mycobacterium intracellulare) and the Mycobacterium abscessus complex (MABSC, M. abscessus subspecies abscessus, massiliense, and bolletii), and can be free-living, biofilm-associated, or amoeba-associated. Although NTM are rarely pathogenic in immunocompetent individuals, those who are immunocompromised - due to either an inherited or acquired immunodeficiency - are highly susceptible to NTM infection (NTMI). Several characteristics such as biofilm formation and the ability of select NTM species to form distinct colony morphotypes all may play a role in pathogenesis not observed in the related, well-characterized pathogen Mycobacterium tuberculosis The recognition of different morphotypes of NTM has been established and characterized since the 1950s, but the mechanisms that underlie colony phenotype change and subsequent differences in pathogenicity are just beginning to be explored. Advances in genomic analysis have led to progress in identifying genes important to the pathogenesis and persistence of MAC disease as well as illuminating genetic aspects of different colony morphotypes. Here we review recent literature regarding NTM ecology and transmission, as well as the factors which regulate colony morphotype and pathogenicity.
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Affiliation(s)
- Tiffany A Claeys
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Richard T Robinson
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
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8
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Samba-Louaka A, Robino E, Cochard T, Branger M, Delafont V, Aucher W, Wambeke W, Bannantine JP, Biet F, Héchard Y. Environmental Mycobacterium avium subsp. paratuberculosis Hosted by Free-Living Amoebae. Front Cell Infect Microbiol 2018; 8:28. [PMID: 29479518 PMCID: PMC5811464 DOI: 10.3389/fcimb.2018.00028] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/23/2018] [Indexed: 01/18/2023] Open
Abstract
Mycobacterium avium subsp. paratuberculosis is responsible for paratuberculosis in animals. This disease, leading to an inflammation of the gastrointestinal tract, has a high impact on animal health and an important economic burden. The environmental life cycle of M. avium subsp. paratuberculosis is poorly understood and several studies suggest that free-living amoebae (FLA) might be a potential environmental host. FLA are protozoa found in water and soil that are described as reservoirs of pathogenic and non-pathogenic bacteria in the environment. Indeed, bacteria able to survive within these amoebae would survive phagocytosis from immune cells. In this study, we assessed the in vitro interactions between several strains of M. avium subsp. paratuberculosis and Acanthamoeba castellanii. The results indicate that the bacteria were able to grow within the amoeba and that they can survive for several days within their host. To explore the presence of M. avium subsp. paratuberculosis in environmental amoebae, we sampled water from farms positive for paratuberculosis. A M. avium subsp. paratuberculosis strain was detected within an environmental amoeba identified as related to the poorly described Rosculus genus. The bacterial strain was genotyped, showing that it was similar to previous infectious strains isolated from cattle. In conclusion, we described that various M. avium subsp. paratuberculosis strains were able to grow within amoebae and that these bacteria could be found on farm within amoebae isolated from the cattle environment. It validates that infected amoebae might be a reservoir and vector for the transmission of M. avium subsp. paratuberculosis.
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Affiliation(s)
- Ascel Samba-Louaka
- Université de Poitiers, Laboratoire Ecologie et Biologie des Interactions, UMR Centre National de la Recherche Scientifique 7267, Equipe Microbiologie de l'Eau, Poitiers, France
| | - Etienne Robino
- Université de Poitiers, Laboratoire Ecologie et Biologie des Interactions, UMR Centre National de la Recherche Scientifique 7267, Equipe Microbiologie de l'Eau, Poitiers, France
| | - Thierry Cochard
- Institut National de la Recherche Agronomique, Université de Tours, UMR1282, Infectiologie et Santé Publique, Nouzilly, France
| | - Maxime Branger
- Institut National de la Recherche Agronomique, Université de Tours, UMR1282, Infectiologie et Santé Publique, Nouzilly, France
| | - Vincent Delafont
- Université de Poitiers, Laboratoire Ecologie et Biologie des Interactions, UMR Centre National de la Recherche Scientifique 7267, Equipe Microbiologie de l'Eau, Poitiers, France
| | - Willy Aucher
- Université de Poitiers, Laboratoire Ecologie et Biologie des Interactions, UMR Centre National de la Recherche Scientifique 7267, Equipe Microbiologie de l'Eau, Poitiers, France
| | - Wilfrid Wambeke
- Institut National de la Recherche Agronomique, Université de Tours, UMR1282, Infectiologie et Santé Publique, Nouzilly, France
| | - John P Bannantine
- National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States
| | - Franck Biet
- Institut National de la Recherche Agronomique, Université de Tours, UMR1282, Infectiologie et Santé Publique, Nouzilly, France
| | - Yann Héchard
- Université de Poitiers, Laboratoire Ecologie et Biologie des Interactions, UMR Centre National de la Recherche Scientifique 7267, Equipe Microbiologie de l'Eau, Poitiers, France
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9
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Buruli Ulcer, a Prototype for Ecosystem-Related Infection, Caused by Mycobacterium ulcerans. Clin Microbiol Rev 2017; 31:31/1/e00045-17. [PMID: 29237707 DOI: 10.1128/cmr.00045-17] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Buruli ulcer is a noncontagious disabling cutaneous and subcutaneous mycobacteriosis reported by 33 countries in Africa, Asia, Oceania, and South America. The causative agent, Mycobacterium ulcerans, derives from Mycobacterium marinum by genomic reduction and acquisition of a plasmid-borne, nonribosomal cytotoxin mycolactone, the major virulence factor. M. ulcerans-specific sequences have been readily detected in aquatic environments in food chains involving small mammals. Skin contamination combined with any type of puncture, including insect bites, is the most plausible route of transmission, and skin temperature of <30°C significantly correlates with the topography of lesions. After 30 years of emergence and increasing prevalence between 1970 and 2010, mainly in Africa, factors related to ongoing decreasing prevalence in the same countries remain unexplained. Rapid diagnosis, including laboratory confirmation at the point of care, is mandatory in order to reduce delays in effective treatment. Parenteral and potentially toxic streptomycin-rifampin is to be replaced by oral clarithromycin or fluoroquinolone combined with rifampin. In the absence of proven effective primary prevention, avoiding skin contamination by means of clothing can be implemented in areas of endemicity. Buruli ulcer is a prototype of ecosystem pathology, illustrating the impact of human activities on the environment as a source for emerging tropical infectious diseases.
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Bouam A, Ghigo E, Drancourt M. Intra-amoebal killing of Mycobacterium ulcerans by Acanthamoeba griffini: A co-culture model. Microb Pathog 2017; 114:1-7. [PMID: 29155010 DOI: 10.1016/j.micpath.2017.11.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 11/13/2017] [Accepted: 11/14/2017] [Indexed: 10/18/2022]
Abstract
Mycobacterium ulcerans, a decaying Mycobacterium marinum derivative is responsible for Buruli ulcer, a notifiable non-contagious disabling infection highly prevalent in some West African countries. Aquatic environments are suspected to host M. ulcerans, however, the exact reservoirs remain unknown. While M. marinum was found to resist amoebal microbicidal activities, this remains unknown for M. ulcerans. In this study M. ulcerans was co-cultured with the moderately halophile Acanthamoeba griffini at 30 °C to probe this tropical amoeba as a potential reservoir for M. ulcerans. In triplicate experiments, we observed engulfment of M. ulcerans by A. griffini trophozoites, followed by an unexpected significant difference of 98.4% (day 1), 99.5% (day 2), 99.5% (day 3) and 99.9% (day 7) between the number of intra-amoebal mycobacteria detected by PCR and the number of viable intra-amoebal mycobacteria measured by 10-week culture. Further encystment revealed only one Mycobacterium organism for 150 A. griffini cysts observed by electron microscopy and the culture of excysted amoebae remained sterile. In conclusion, these data install M. ulcerans as susceptible to A. griffini microbicidal activities rendering this amoeba species an unlikely host of M. ulcerans in natural environments.
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Affiliation(s)
- Amar Bouam
- Aix Marseille Université, URMITE, UMR CNRS 7278, IRD 198, INSERM 1095, IHU Méditerranée Infection, Marseille 13005, France
| | - Eric Ghigo
- Aix Marseille Université, URMITE, UMR CNRS 7278, IRD 198, INSERM 1095, IHU Méditerranée Infection, Marseille 13005, France
| | - Michel Drancourt
- Aix Marseille Université, URMITE, UMR CNRS 7278, IRD 198, INSERM 1095, IHU Méditerranée Infection, Marseille 13005, France.
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11
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Diversity of free-living amoebae in soils and their associated human opportunistic bacteria. Parasitol Res 2017; 116:3151-3162. [DOI: 10.1007/s00436-017-5632-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/21/2017] [Indexed: 02/06/2023]
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12
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Azumah BK, Addo PG, Dodoo A, Awandare G, Mosi L, Boakye DA, Wilson MD. Experimental demonstration of the possible role of Acanthamoeba polyphaga in the infection and disease progression in Buruli Ulcer (BU) using ICR mice. PLoS One 2017; 12:e0172843. [PMID: 28329001 PMCID: PMC5362167 DOI: 10.1371/journal.pone.0172843] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 02/10/2017] [Indexed: 11/18/2022] Open
Abstract
The transmission of Buruli ulcer (BU), caused by Mycobacterium ulcerans (MU), remains puzzling although a number of hypothesis including through bites of infected aquatic insects have been proposed. We report the results of experiments using ICR mice that give credence to our hypothesis that Acanthamoeba species may play a role in BU transmission. We cocultured MU N2 and MU 1615 which expresses red fluorescent protein (RFP) and Acanthamoeba polyphaga (AP), and confirmed infected AP by Ziehl-Neelsen (ZN) staining. We tested for viability of MU inside AP and observed strong RFP signals inside both trophozoites and cysts after 3 and 42 days of coculturing respectively. ICR mice were topically treated, either on shaved intact or shaved pinpricked rumps, with one of the following; MU N2 only (2.25 x 106 colony forming units [CFU] / ml), MU N2:AP coculture (2.96 x 104 CFU: 1.6 x 106 cells/ml), AP only (1.6 x 106 cells/ml), PYG medium and sterile distilled water. Both MU N2 only and MU N2:AP elicited reddening on day (D) 31; edema on D 45 and D 44 respectively, and ulcers on D 49 at pinpricked sites only. To ascertain infectivity and pathogenicity of MU N2 only and MU N2:AP, and compare their virulence, the standard mouse footpad inoculation method was used. MU N2:AP elicited reddening in footpads by D 3 compared to D 14 with MU N2 only of the same dose of MU N2 (2.96 x 104 CFU). ZN-stained MU were observed in both thin sectioned and homogenized lesions, and aspirates from infected sites. Viable MU N2 were recovered from cultures of the homogenates and aspirates. This study demonstrates in ICR mice MU transmission via passive infection, and shows that punctures in the skin are prerequisite for infection, and that coculturing of MU with AP enhances pathogenesis.
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Affiliation(s)
- Bright K. Azumah
- Department of Animal Experimentation, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Phyllis G. Addo
- Department of Animal Experimentation, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
- * E-mail: (PGA); (MDW)
| | - Alfred Dodoo
- Department of Electron Microscopy and Histopathology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
| | - Gordon Awandare
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Lydia Mosi
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Daniel A. Boakye
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
| | - Michael D. Wilson
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
- * E-mail: (PGA); (MDW)
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13
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Zingue D, Bouam A, Militello M, Drancourt M. High-Throughput Carbon Substrate Profiling of Mycobacterium ulcerans Suggests Potential Environmental Reservoirs. PLoS Negl Trop Dis 2017; 11:e0005303. [PMID: 28095422 PMCID: PMC5271411 DOI: 10.1371/journal.pntd.0005303] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 01/27/2017] [Accepted: 01/04/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Mycobacterium ulcerans is a close derivative of Mycobacterium marinum and the agent of Buruli ulcer in some tropical countries. Epidemiological and environmental studies pointed towards stagnant water ecosystems as potential sources of M. ulcerans, yet the ultimate reservoirs remain elusive. We hypothesized that carbon substrate determination may help elucidating the spectrum of potential reservoirs. METHODOLOGY/PRINCIPAL FINDINGS In a first step, high-throughput phenotype microarray Biolog was used to profile carbon substrates in one M. marinum and five M. ulcerans strains. A total of 131/190 (69%) carbon substrates were metabolized by at least one M. ulcerans strain, including 28/190 (15%) carbon substrates metabolized by all five M. ulcerans strains of which 21 substrates were also metabolized by M. marinum. In a second step, 131 carbon substrates were investigated, through a bibliographical search, for their known environmental sources including plants, fruits and vegetables, bacteria, algae, fungi, nematodes, mollusks, mammals, insects and the inanimate environment. This analysis yielded significant association of M. ulcerans with bacteria (p = 0.000), fungi (p = 0.001), algae (p = 0.003) and mollusks (p = 0.007). In a third step, the Medline database was cross-searched for bacteria, fungi, mollusks and algae as potential sources of carbon substrates metabolized by all tested M. ulcerans; it indicated that 57% of M. ulcerans substrates were associated with bacteria, 18% with alga, 11% with mollusks and 7% with fungi. CONCLUSIONS This first report of high-throughput carbon substrate utilization by M. ulcerans would help designing media to isolate and grow this pathogen. Furthermore, the presented data suggest that potential M. ulcerans environmental reservoirs might be related to micro-habitats where bacteria, fungi, algae and mollusks are abundant. This should be followed by targeted investigations in Buruli ulcer endemic regions.
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Affiliation(s)
- Dezemon Zingue
- Aix Marseille Univ, INSERM, CNRS, IRD, URMITE, Marseille, France
| | - Amar Bouam
- Aix Marseille Univ, INSERM, CNRS, IRD, URMITE, Marseille, France
| | - Muriel Militello
- Aix Marseille Univ, INSERM, CNRS, IRD, URMITE, Marseille, France
| | - Michel Drancourt
- Aix Marseille Univ, INSERM, CNRS, IRD, URMITE, Marseille, France
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Lamelas A, Ampah KA, Aboagye S, Kerber S, Danso E, Asante-Poku A, Asare P, Parkhill J, Harris SR, Pluschke G, Yeboah-Manu D, Röltgen K. Spatiotemporal Co-existence of Two Mycobacterium ulcerans Clonal Complexes in the Offin River Valley of Ghana. PLoS Negl Trop Dis 2016; 10:e0004856. [PMID: 27434064 PMCID: PMC4951013 DOI: 10.1371/journal.pntd.0004856] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 06/27/2016] [Indexed: 11/28/2022] Open
Abstract
In recent years, comparative genome sequence analysis of African Mycobacterium ulcerans strains isolated from Buruli ulcer (BU) lesion specimen has revealed a very limited genetic diversity of closely related isolates and a striking association between genotype and geographical origin of the patients. Here, we compared whole genome sequences of five M. ulcerans strains isolated in 2004 or 2013 from BU lesions of four residents of the Offin river valley with 48 strains isolated between 2002 and 2005 from BU lesions of individuals residing in the Densu river valley of Ghana. While all M. ulcerans isolates from the Densu river valley belonged to the same clonal complex, members of two distinct clonal complexes were found in the Offin river valley over space and time. The Offin strains were closely related to genotypes from either the Densu region or from the Asante Akim North district of Ghana. These results point towards an occasional involvement of a mobile reservoir in the transmission of M. ulcerans, enabling the spread of bacteria across different regions. Infection with Mycobacterium ulcerans causes the debilitating skin disease Buruli ulcer. Until today, transmission pathways and reservoirs of this emerging pathogen are not well understood. Generally, it is assumed that infection occurs after contact with potential environmental sources of M. ulcerans through puncture wounds or lacerations or via invertebrate vectors, such as aquatic insects contaminated with the bacteria. Comparative genome analyses of M. ulcerans strains isolated from patients living in the same BU endemic areas have revealed a close relationship between the genotype detected and the geographical origin, indicating that the reservoir of the pathogen is relatively fixed in space. In the present study, we report the co-circulation of two distinct M. ulcerans clonal complexes in the same BU endemic area over space and time. Since members of these two clonal complexes were closely related to strains from either the Densu river valley or the Asante Akim North district of Ghana, we conclude that a mobile reservoir of M. ulcerans may be involved in the occasional spread of the bacteria across different regions.
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Affiliation(s)
- Araceli Lamelas
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Red de Estudios Moleculares Avanzados, Instituto de Ecologia, A.C., Veracruz, México
| | - Kobina Assan Ampah
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Noguchi Memorial Institute for Medical Research, Legon, Ghana
| | - Samuel Aboagye
- Noguchi Memorial Institute for Medical Research, Legon, Ghana
| | - Sarah Kerber
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Emelia Danso
- Noguchi Memorial Institute for Medical Research, Legon, Ghana
| | | | - Prince Asare
- Noguchi Memorial Institute for Medical Research, Legon, Ghana
| | | | | | - Gerd Pluschke
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
| | | | - Katharina Röltgen
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
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15
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Tobias NJ, Ammisah NA, Ahortor EK, Wallace JR, Ablordey A, Stinear TP. Snapshot fecal survey of domestic animals in rural Ghana for Mycobacterium ulcerans. PeerJ 2016; 4:e2065. [PMID: 27280071 PMCID: PMC4893338 DOI: 10.7717/peerj.2065] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 05/02/2016] [Indexed: 11/20/2022] Open
Abstract
Identifying the source reservoirs of Mycobacterium ulcerans is key to understanding the mode of transmission of this pathogen and controlling the spread of Buruli ulcer (BU). In Australia, the native possum can harbor M. ulcerans in its gastrointestinal tract and shed high concentrations of the bacteria in its feces. To date, an analogous animal reservoir in Africa has not been identified. Here we tested the hypothesis that common domestic animals in BU endemic villages of Ghana are reservoir species analogous to the Australian possum. Using linear-transects at 10-meter intervals, we performed systematic fecal surveys across four BU endemic villages and one non-endemic village in the Asante Akim North District of Ghana. One hundred and eighty fecal specimens from a single survey event were collected and analyzed by qPCR for the M. ulcerans diagnostic DNA targets IS2404 and KR-B. Positive and negative controls performed as expected but all 180 test samples were negative. This structured snapshot survey suggests that common domestic animals living in and around humans do not shed M. ulcerans in their feces. We conclude that, unlike the Australian native possum, domestic animals in rural Ghana are unlikely to be major reservoirs of M. ulcerans.
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Affiliation(s)
- Nicholas J Tobias
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity , Melbourne , Australia
| | - Nana Ama Ammisah
- Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of Ghana , Legon , Ghana
| | - Evans K Ahortor
- Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana; School of Pharmacy & Pharmaceutical Science, Cardiff University, Cardiff, United Kingdom
| | - John R Wallace
- Department of Biology, Millersville University of Pennsylvania , Millersville, PA , United States
| | - Anthony Ablordey
- Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of Ghana , Legon , Ghana
| | - Timothy P Stinear
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity , Melbourne , Australia
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16
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Barka EA, Vatsa P, Sanchez L, Gaveau-Vaillant N, Jacquard C, Meier-Kolthoff JP, Klenk HP, Clément C, Ouhdouch Y, van Wezel GP. Taxonomy, Physiology, and Natural Products of Actinobacteria. Microbiol Mol Biol Rev 2016; 80:1-43. [PMID: 26609051 PMCID: PMC4711186 DOI: 10.1128/mmbr.00019-15] [Citation(s) in RCA: 952] [Impact Index Per Article: 119.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Actinobacteria are Gram-positive bacteria with high G+C DNA content that constitute one of the largest bacterial phyla, and they are ubiquitously distributed in both aquatic and terrestrial ecosystems. Many Actinobacteria have a mycelial lifestyle and undergo complex morphological differentiation. They also have an extensive secondary metabolism and produce about two-thirds of all naturally derived antibiotics in current clinical use, as well as many anticancer, anthelmintic, and antifungal compounds. Consequently, these bacteria are of major importance for biotechnology, medicine, and agriculture. Actinobacteria play diverse roles in their associations with various higher organisms, since their members have adopted different lifestyles, and the phylum includes pathogens (notably, species of Corynebacterium, Mycobacterium, Nocardia, Propionibacterium, and Tropheryma), soil inhabitants (e.g., Micromonospora and Streptomyces species), plant commensals (e.g., Frankia spp.), and gastrointestinal commensals (Bifidobacterium spp.). Actinobacteria also play an important role as symbionts and as pathogens in plant-associated microbial communities. This review presents an update on the biology of this important bacterial phylum.
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Affiliation(s)
- Essaid Ait Barka
- Laboratoire de Stress, Défenses et Reproduction des Plantes, Unité de Recherche Vignes et Vins de Champagne, UFR Sciences, UPRES EA 4707, Université de Reims Champagne-Ardenne, Reims, France
| | - Parul Vatsa
- Laboratoire de Stress, Défenses et Reproduction des Plantes, Unité de Recherche Vignes et Vins de Champagne, UFR Sciences, UPRES EA 4707, Université de Reims Champagne-Ardenne, Reims, France
| | - Lisa Sanchez
- Laboratoire de Stress, Défenses et Reproduction des Plantes, Unité de Recherche Vignes et Vins de Champagne, UFR Sciences, UPRES EA 4707, Université de Reims Champagne-Ardenne, Reims, France
| | - Nathalie Gaveau-Vaillant
- Laboratoire de Stress, Défenses et Reproduction des Plantes, Unité de Recherche Vignes et Vins de Champagne, UFR Sciences, UPRES EA 4707, Université de Reims Champagne-Ardenne, Reims, France
| | - Cedric Jacquard
- Laboratoire de Stress, Défenses et Reproduction des Plantes, Unité de Recherche Vignes et Vins de Champagne, UFR Sciences, UPRES EA 4707, Université de Reims Champagne-Ardenne, Reims, France
| | | | - Hans-Peter Klenk
- School of Biology, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Christophe Clément
- Laboratoire de Stress, Défenses et Reproduction des Plantes, Unité de Recherche Vignes et Vins de Champagne, UFR Sciences, UPRES EA 4707, Université de Reims Champagne-Ardenne, Reims, France
| | - Yder Ouhdouch
- Faculté de Sciences Semlalia, Université Cadi Ayyad, Laboratoire de Biologie et de Biotechnologie des Microorganismes, Marrakesh, Morocco
| | - Gilles P van Wezel
- Molecular Biotechnology, Institute of Biology, Sylvius Laboratories, Leiden University, Leiden, The Netherlands
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Lepra und Buruli-Ulkus. Monatsschr Kinderheilkd 2015. [DOI: 10.1007/s00112-015-3378-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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18
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Duedu KO, Karikari YA, Attah SK, Ayeh-Kumi PF. Prevalence of intestinal parasites among patients of a Ghanaian psychiatry hospital. BMC Res Notes 2015; 8:651. [PMID: 26541287 PMCID: PMC4635531 DOI: 10.1186/s13104-015-1634-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 10/26/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Neglected tropical diseases are of major concern to sub-Saharan African countries. Though efforts to monitor the prevalence and control are in place, these are mostly restricted to groups within the population. This study was performed to determine the prevalence among patients of a Ghanaian psychiatric hospital and find out whether there is a reason for active monitoring in this population. METHODS A cross-sectional study was performed to determine the prevalence of intestinal parasites among patients of a Ghanaian psychiatric hospital. Stool samples were collected and analyzed in addition to data. RESULTS Of the 111 patients studied, asymptomatic carriage of parasites was 13.5 % and was higher in males (18.8 %) than in females (4.8 %). Carriage of parasites decreased with age but increase with duration of admission. CONCLUSION This is the first report of parasitic pathogens among patients of a psychiatric institution in Ghana. The data shows that there are risks of transmission of infectious diseases via the oral route hence, the need for regular monitoring and intervention is emphasized.
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Affiliation(s)
- Kwabena O Duedu
- Department of Medical Microbiology, School of Biomedical and Allied Health Sciences, University of Ghana, Accra, Ghana.
- Department of Medical Laboratory Sciences, School of Biomedical and Allied Health Sciences, University of Ghana, Accra, Ghana.
- Department of Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana.
| | - Yaw A Karikari
- Department of Medical Laboratory Sciences, School of Biomedical and Allied Health Sciences, University of Ghana, Accra, Ghana.
| | - Simon K Attah
- Department of Medical Microbiology, School of Biomedical and Allied Health Sciences, University of Ghana, Accra, Ghana.
| | - Patrick F Ayeh-Kumi
- Department of Medical Microbiology, School of Biomedical and Allied Health Sciences, University of Ghana, Accra, Ghana.
- Department of Medical Laboratory Sciences, School of Biomedical and Allied Health Sciences, University of Ghana, Accra, Ghana.
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Santos-Montañez J, Benavides-Montaño JA, Hinz AK, Vadyvaloo V. Yersinia pseudotuberculosis IP32953 survives and replicates in trophozoites and persists in cysts of Acanthamoeba castellanii. FEMS Microbiol Lett 2015; 362:fnv091. [PMID: 26025069 DOI: 10.1093/femsle/fnv091] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2015] [Indexed: 12/22/2022] Open
Abstract
Yersinia pseudotuberculosis is a foodborne enteric pathogen that causes a mild self-limiting diarrhea in humans. Yersinia pseudotuberculosis is able to persist in soil and water and in association with fresh produce, but the mechanism by which it persists is unknown. It has been shown that Y. pseudotuberculosis co-occurs with protozoans in these environments; therefore, this study investigates if bacterivorous free-living amoeba (FLA) are able to support persistence of Y. pseudotuberculosis. Coculture studies of Y. pseudotuberculosis and the prototype FLA, Acanthamoeba castellanii revealed that bacteria had an enhanced capacity to survive in association with amoeba and in the absence of any cytotoxic effects. Yersinia pseudotuberculosis is able to survive and replicate in trophozoites specifically localized within vacuoles, and persists within cysts over a period of at least a week. These data present the first evidence that Y. pseudotuberculosis is able to resist the bacterivorous nature of FLA and instead exhibits an enhanced ability to replicate and persist in coculture with amoeba. This study sheds light on the potential role of FLA in the ecology of Y. pseudotuberculosis which may have implications for food safety.
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Affiliation(s)
- Jennifer Santos-Montañez
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, WA 99164, USA
| | - Javier A Benavides-Montaño
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, WA 99164, USA Departamento Ciencia Animal, Universidad Nacional de Colombia, A. A. 237, Palmira Valle, Colombia
| | - Angela K Hinz
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, WA 99164, USA
| | - Viveka Vadyvaloo
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, WA 99164, USA
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Mycobacterium ulcerans Disease (Buruli Ulcer): Potential Reservoirs and Vectors. CURRENT CLINICAL MICROBIOLOGY REPORTS 2015. [DOI: 10.1007/s40588-015-0013-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Carolan K, Ebong SMA, Garchitorena A, Landier J, Sanhueza D, Texier G, Marsollier L, Gall PL, Guégan JF, Lo Seen D. Ecological niche modelling of Hemipteran insects in Cameroon; the paradox of a vector-borne transmission for Mycobacterium ulcerans, the causative agent of Buruli ulcer. Int J Health Geogr 2014; 13:44. [PMID: 25344052 PMCID: PMC4213541 DOI: 10.1186/1476-072x-13-44] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 10/13/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The mode of transmission of the emerging neglected disease Buruli ulcer is unknown. Several potential transmission pathways have been proposed, such as amoebae, or transmission through food webs. Several lines of evidence have suggested that biting aquatic insects, Naucoridae and Belostomatidae, may act as vectors, however this proposal remains controversial. MATERIALS AND METHODS Herein, based on sampling in Cameroon, we construct an ecological niche model of these insects to describe their spatial distribution. We predict their distribution across West Africa, describe important environmental drivers of their abundance, and examine the correlation between their abundance and Buruli ulcer prevalence in the context of the Bradford-Hill guidelines. RESULTS We find a significant positive correlation between the abundance of the insects and the prevalence of Buruli ulcer. This correlation changes in space and time, it is significant in one Camerounese study region in (Akonolinga) and not other (Bankim). We discuss notable environmental differences between these regions. CONCLUSION We interpret the presence of, and change in, this correlation as evidence (though not proof) that these insects may be locally important in the environmental persistence, or transmission, of Mycobacterium. ulcerans. This is consistent with the idea of M. ulcerans as a pathogen transmitted by multiple modes of infection, the importance of any one pathway changing from region to region, depending on the local environmental conditions.
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Affiliation(s)
- Kevin Carolan
- Unité mixte de recherche (UMR) Maladies Infectieuses et Vecteurs : Écologie, Génétique, Evolution, et Contrôle (MIVEGEC) IRD-CNRS-Universities of Montpellier I and II, Centre IRD de Montpellier, BP 64501, 34394 Montpellier Cedex 5, France.
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