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

ABSTRACT

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 Beta-lactam antibiotics was in excess of 50of 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