Aquatic snails, passive hosts of Mycobacterium ulcerans.

Accumulative indirect evidence of the epidemiology of Mycobacterium ulcerans infections causing chronic skin ulcers (i.e., Buruli ulcer disease) suggests that the development of this pathogen and its transmission to humans are related predominantly to aquatic environments.

Aquatic plants stimulate the growth of and biofilm formation by Mycobacterium ulcerans in axenic culture and harbor these bacteria in the environment.

Mycobacterium ulcerans is the causative agent of Buruli ulcer, one of the most common mycobacterial diseases of humans. Recent studies have implicated aquatic insects in the transmission of this pathogen, but the contributions of other elements of the environment remain largely unknown. We report here that crude extracts from two green algae added to the BACTEC 7H12B culture medium halved the doubling time of M.

Susceptibility of Mycobacterium ulcerans to a combination of amikacin/rifampicin.

The effectiveness of rifampicin (RIF), amikacin (AMK) and their combination were estimated in the treatment of mice experimentally infected by Mycobacterium ulcerans and the risk of relapse after the treatment was evaluated. After 7 weeks of treatment with RIF or with the combination of AMK/RIF and 8 weeks with AMK alone, no viable bacilli were found in the infected tissues and these remained uninfected during the following 6 months. Among the mice treated with AMK alone, three mice relapsed, but the minimal inhibitory concentration of AMK for these isolates remained unchanged.

Isolation of three Mycobacterium ulcerans strains resistant to rifampin after experimental chemotherapy of mice.

By use of a murine model for Buruli ulcer, Mycobacterium ulcerans was found to be susceptible to rifampin, with the MIC being 0.5 to 1 micro g/ml. Three mutants were isolated after rifampin monotherapy.

Aquatic insects as a vector for Mycobacterium ulcerans.

Mycobacterium ulcerans is an emerging environmental pathogen which causes chronic skin ulcers (i.e., Buruli ulcer) in otherwise healthy humans living in tropical countries, particularly those in Africa.