Longitudinal assessment of the bacterial burden of buruli ulcer wounds during treatment

Background: Bacterial contamination is common to all wounds. The bacterial burden of wounds has been found to have an inverse relationship with chronic wound healing. In seeking to develop a better understanding of the evolution of Buruli ulcer (BU) wounds, we performed a longitudinal study to quantify the bacterial burden of BU wounds during the course of streptomycin/rifampicin (SR) treatment. Methods: Twenty-one IS2404 polymerase chain reaction confirmed patients were longitudinally followed during the course of their treatment. Swab or tissue samples obtained from the lesions were quantitatively analyzed to determine the bacterial burden pre-, during, and post-SR treatment. Furthermore, the species of bacterial isolates obtained at these time points were also identified. Results: Based on the determination of the bacterial burden, 18/22 (81.8%) pretreatment, 15/25 (57.7%) during treatment, and 36/48 (75.0%) posttreatment samples were classified as superinfected, respectively. Thirty bacterial species including two species of anaerobic Clostridia (Clostridium perfringens and Clostridium sporogenes) were identified among 114 isolates. While Enterococcus faecalis, Pseudomonas aeruginosa, and Chryseomonas luteola dominated pretreatment, P. aeruginosa dominated during and posttreatment. Conclusions: Most BU patients presented with lesions with a high bacterial load which increased significantly posttreatment. Therefore, good wound care is necessary to control the microbial burden of BU wounds, especially posttreatment to minimize complications