Species Distribution and Antibiotic Resistance in Coagulase-negative Staphylococci Colonizing the Gastrointestinal Tract of Children in Ile-Ife, Nigeria

Purpose: The antimicrobial susceptibility of 149 coagulase-negative staphylococci (CoNS) isolates from faecal samples of children in Ile-Ife, Nigeria, was evaluated in order to determine their contribution to antimicrobial resistance in the community. Methods: The isolates were identified to the species level by conventional methods, and their susceptibility to 20 antibiotics was tested by disk diffusion and to vancomycin by agar dilution. Results: The species distribution was as follows: Staphylococcus epidermidis 45 (30.2 %), S. haemolyticus, 26 (17.5 %); S. capitis, 24 (16.1 %); S. xylosus, 11 (7.4 %); S. saprophyticus, 8 (5.4 %); S. warneri, 8 (5.4 %); S. hominis, 6 (4.0 %); S. schleiferi, 5 (3.3 %); S. lugdunensis, 3 (2.0 %) and S. capitis sub ureolyticus, 3 (2.0 %) and isolates from other CoNS species 10 (6.7 %). Resistance to the βlactam antibiotics was in excess of 50 % of the isolates tested whilst there was significant incidence of resistance to cotrimoxazole, chloramphenicol, tetracycline, erythromycin, fusidic acid and norfloxacin. The highest percentage of oxacillin resistance was found among S. haemolyticus (46.2%) while the lowest was in S. capitis (8.3%). Reduced susceptibility (MIC ≥ 4mg/L) to vancomycin was shown by both oxacillin-resistant and susceptible CoNS species. Conclusion: The gastrointestinal tracts of children could serve as a reservoir for antibiotic-resistant CoNS, some of which had reduced susceptibility to vancomycin.