Causative agents and antimicrobial resistance patterns of human skin and soft tissue infections in Bagamoyo, Tanzania

Few epidemiological studies have been carried out to assess the aetiology and antimicrobial susceptibility patterns of pathogens giving rise to skin and soft tissue infections (SSTIs) in sub-Saharan Africa. In the present study from six healthcare facilities in Bagamoyo, Tanzania, wound swabs from outpatients with SSTIs were analysed by a suite of methods, including microbiological culture techniques, matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry and resistance testing. Among 185 patients with SSTIs, 179 (96.8%) swabs showed microbiological growth. In total, 327 organisms were found, of which 285 were of potential aetiological relevance. Staphylococcus aureus was the predominant pathogen (prevalence: 71.4%), followed by the Gram-negative bacteria Enterobacter cloacae complex (14.6%), Klebsiella pneumoniae (12.4%) and Pseudomonas aeruginosa (11.8%). While one out of three isolates of S. aureus showed resistance to macrolides, tetracyclines, cotrimoxazole and clindamycin, only a single methicillin-resistant S. aureus (MRSA) strain was found. In Gram-negative bacteria, resistance to ampicillin and cotrimoxazole was common, while extended-spectrum beta-lactamases were rarely detected (<1%). We conclude that S. aureus was the most frequently detected pathogen in community-acquired SSTIs in Bagamoyo, Tanzania. Resistance to commonly prescribed oral antibiotics was considerable, but multi-resistant strains were rarely encountered. Monitoring of antibiotic susceptibility patterns in SSTIs is important to provide specific data for tailoring treatment recommendations.