Abstract
BackgroundThe reservoir and mode of transmission of Mycobacterium ulcerans, the causative agent of Buruli ulcer, remain unknown. Ecological, genetic and epidemiological information nonetheless suggests that M. ulcerans may reside in aquatic protozoa.Methodology/Principal FindingsWe experimentally infected Acanthamoeba polyphaga with M. ulcerans and found that the bacilli were phagocytised, not digested and remained viable for the duration of the experiment. Furthermore, we collected 13 water, 90 biofilm and 45 detritus samples in both Buruli ulcer endemic and non-endemic communities in Ghana, from which we cultivated amoeboid protozoa and mycobacteria. M. ulcerans was not isolated, but other mycobacteria were as frequently isolated from intracellular as from extracellular sources, suggesting that they commonly infect amoebae in nature. We screened the samples as well as the amoeba cultures for the M. ulcerans markers IS2404, IS2606 and KR-B. IS2404 was detected in 2% of the environmental samples and in 4% of the amoeba cultures. The IS2404 positive amoeba cultures included up to 5 different protozoan species, and originated both from Buruli ulcer endemic and non-endemic communities.Conclusions/SignificanceThis is the first report of experimental infection of amoebae with M. ulcerans and of the detection of the marker IS2404 in amoeba cultures isolated from the environment. We conclude that amoeba are potential natural hosts for M. ulcerans, yet remain sceptical about their implication in the transmission of M. ulcerans to humans and their importance in the epidemiology of Buruli ulcer.
Highlights
Most mycobacteria are environmental opportunistic species that only occasionally infect humans [1]
Buruli ulcer (BU) is a devastating skin disease caused by Mycobacterium ulcerans, an environmental bacterium that is probably linked to slow-running water
It is unlikely to occur free-living, but even though M. ulcerans DNA has been detected in quite a few different organisms, it is still not clear what its real reservoir is
Summary
Most mycobacteria are environmental opportunistic species that only occasionally infect humans [1]. Few mycobacterial species are known to be obligate parasites, such as Mycobacterium tuberculosis and M. leprae, the causative agents of tuberculosis and leprosy respectively. The third most common mycobacterial disease, Buruli ulcer (BU), is caused by M. ulcerans, an environmental opportunistic mycobacterium. The main reservoir of M. ulcerans and its transmission from the environment to humans remain unknown. Epidemiological data from Africa suggest that proximity to slow-flowing or stagnant water best explains the distribution pattern of BU [3]. The reservoir and mode of transmission of Mycobacterium ulcerans, the causative agent of Buruli ulcer, remain unknown. Ecological, genetic and epidemiological information suggests that M. ulcerans may reside in aquatic protozoa
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
