In vitro studies of antibiotic sensitivities of Streptomyces somaliensis--a cause of human actinomycetoma.

Ten Streptomyces somaliensis strains isolated from mycetoma patients were tested in vitro against 13 antibacterial agents. Rifampicin was the most effective antibiotic in terms of low minimum inhibitory concentration (MIC) followed by erythromycin, tobramycin, fusidic acid and streptomycin sulphate. The S. somaliensis strains were all resistant to trimethoprim, even though the combination of sulphamethoxazole and trimethoprim is commonly used as treatment.