Abstract:
Background: Buruli ulcer (BU) is a skin disease caused by Mycobacterium ulcerans and is the second most common
mycobacterial disease after tuberculosis in Ghana and Côte d’Ivoire. M. ulcerans produces mycolactone, an
immunosuppressant macrolide toxin, responsible for the characteristic painless nature of the infection. Secondary
infection of ulcers before, during and after treatment has been associated with delayed wound healing and
resistance to streptomycin and rifampicin. However, not much is known of the bacteria causing these infections as
well as antimicrobial drugs for treating the secondary microorganism. This study sought to identify secondary
microbial infections in BU lesions and to determine their levels of antibiotic resistance due to the prolonged
antibiotic therapy required for Buruli ulcer.
Results: Swabs from fifty-one suspected BU cases were sampled in the Amansie Central District from St. Peters
Hospital (Jacobu) and through an active case surveillance. Forty of the samples were M. ulcerans (BU) positive.
Secondary bacteria were identified in all sampled lesions (N = 51). The predominant bacteria identified in both BU
and Non-BU groups were Staphylococci spp and Bacilli spp. The most diverse secondary bacteria were detected
among BU patients who were not yet on antibiotic treatment. Fungal species identified were Candida spp,
Penicillium spp and Trichodema spp. Selected secondary bacteria isolates were all susceptible to clarithromycin and
amikacin among both BU and Non-BU patients. Majority, however, had high resistance to streptomycin.
Conclusions: Microorganisms other than M. ulcerans colonize and proliferate on BU lesions. Secondary
microorganisms of BU wounds were mainly Staphylococcus spp, Bacillus spp and Pseudomonas spp. These
secondary microorganisms were less predominant in BU patients under treatment compared to those without
treatment. The delay in healing that are experienced by some BU patients could be as a result of these bacteria
and fungi colonizing and proliferating in BU lesions. Clarithromycin and amikacin are likely suitable drugs for
clearance of secondary infection of Buruli ulcer.
