Antimicrobial Resistance Pattern of Coagulase-negative Staphylococci isolates from Medical Students of Some Nigerian Teaching Hospitals

Abstract

The antimicrobial resistance or otherwise of Coagulase-negative Staphylococci (CoNS) isolates from medical students of some South Eastern Nigerian Universities were determined. Swab samples were obtained from the students and were cultured for CoNS using standard microbiological methods. Isolates obtained were assayed for antibiotic resistance using disc diffusion method. MecA and blaZ genes on 533bp and 510bp respectively, of the isolates were amplify using the Polymerase Chain Reaction (PCR). Fingerprinting of isolates’ genomes was also conducted by Randomly Amplified Polymorphic DNA. Results obtained showed that of the 200 students screened, 26 (13.0%) harbour CoNS. Observed resistance against the tested antimicrobials were as follows; trimethoprim (100%), oxacillin, penicillin, ampicillin (88.5%), clindamycin (61.5%), ciprofloxacin (57.7%), erythromycin and vancomycin (15.4%), and nitrofurantoin (0%). All the isolates showed multi-drug resistance to at least four antibiotics assessed. PCR amplification yielded no antibiotic resistant gene and fingerprinting by RAPD revealed that the isolates were not genetically related. The elevated level of resistance among isolated CoNS to the antimicrobials studied is of great concern. The isolates can serve as reservoirs of resistance determinants that can be transmitted to pathogens. The spread of CoNS can however be prevented by effective infection control measures. This study underlines the necessity for policies on the use of antibiotics in healthcare and agriculture, and the development and enforcement of measures that will prevent the spread of CoNS in Nigerian hospitals. It also calls for periodic studies for the evaluation of current resistance patterns of CoNS.

Keywords: Antimicrobial resistance, Coagulase-Negative Staphylococci, Resistance determinant reservoirs.