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Investigating the role of free-living amoebae as a reservoir for Mycobacterium ulcerans

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Show simple item record Amissah, N. A. Gryseels, S. Tobias, N. J. Ravadgar, B. Suzuki, M. Vandelannoote, K. Durnez, L. Leirs, H. Stinear, T. P. Portaels, F. Ablordey, A. Eddyani, M. 2014-12-03T14:51:52Z 2014-12-03T14:51:52Z 2014
dc.identifier.issn 1935-2727
dc.identifier.other ITG-B6B
dc.identifier.other ITG-B7B
dc.identifier.other ITG-X9B
dc.identifier.other ITG-BLA
dc.identifier.other DBM
dc.identifier.other U-MYCOB
dc.identifier.other JIF
dc.identifier.other DOI
dc.identifier.other FTA
dc.identifier.other E-only
dc.identifier.other Abstract
dc.identifier.other UPD57
dc.description.abstract BACKGROUND: The reservoir and mode of transmission of Mycobacterium ulcerans, the causative agent of Buruli ulcer, still remain a mystery. It has been suggested that M. ulcerans persists with difficulty as a free-living organism due to its natural fragility and inability to withstand exposure to direct sunlight, and thus probably persists within a protective host environment. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the role of free-living amoebae as a reservoir of M. ulcerans by screening the bacterium in free-living amoebae (FLA) cultures isolated from environmental specimens using real-time PCR. We also followed the survival of M. ulcerans expressing green fluorescence protein (GFP) in Acanthameoba castellanii by flow cytometry and observed the infected cells using confocal and transmission electron microscopy for four weeks in vitro. IS2404 was detected by quantitative PCR in 4.64% of FLA cultures isolated from water, biofilms, detritus and aerosols. While we could not isolate M. ulcerans, 23 other species of mycobacteria were cultivated from inside FLA and/or other phagocytic microorganisms. Laboratory experiments with GFP-expressing M. ulcerans in A. castellani trophozoites for 28 days indicated the bacteria did not replicate inside amoebae, but they could remain viable at low levels in cysts. Transmission electron microscopy of infected A. castellani confirmed the presence of bacteria within both trophozoite vacuoles and cysts. There was no correlation of BU notification rate with detection of the IS2404 in FLA (r = 0.07, n = 539, p = 0.127). CONCLUSION/SIGNIFICANCE: This study shows that FLA in the environment are positive for the M. ulcerans insertion sequence IS2404. However, the detection frequency and signal strength of IS2404 positive amoabae was low and no link with the occurrence of BU was observed. We conclude that FLA may host M. ulcerans at low levels in the environment without being directly involved in the transmission to humans. en_US
dc.language English en_US
dc.subject Bacterial diseases en_US
dc.subject Tuberculosis en_US
dc.subject Mycobacterium tuberculosis en_US
dc.subject Reservoirs en_US
dc.subject Amoeba en_US
dc.subject Free-living ameba en_US
dc.subject Acanthamoeba castellanii en_US
dc.subject Screening en_US
dc.subject Fluorescence in situ hybridization en_US
dc.subject Isolation en_US
dc.subject IS2404 en_US
dc.subject DNA en_US
dc.subject Ghana en_US
dc.subject Africa, West en_US
dc.title Investigating the role of free-living amoebae as a reservoir for Mycobacterium ulcerans en_US
dc.type Article-E en_US
dc.citation.issue 9 en_US
dc.citation.jtitle PLoS Neglected Tropical Diseases en_US
dc.citation.volume 8 en_US
dc.citation.pages e3148 en_US
dc.citation.jabbreviation PLoS Negl Trop Dis en_US

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