The screening of multi-drug resistance (MDR) susceptibilities of Staphylococcus aureus and Staphylococcus epidermidis to methicillin and vancomycin in teaching hospitals in Nigeria

Abstract

Background: In Nigeria, the widespread use of antibiotics had led to high levels of resistance among bacterial isolates from patients with nosocomial infections. This had led to prolonged hospital stay and antibiotic therapy, especially β-lactam antibiotics that predispose patients to acquisition of methicillin -resistant Staph. aureus (MRSA) and coagulase negative resistant staphylococci.
Objective: to evaluate the resistant pattern of multi-drug resistant strains of 80 clinical Staph. aureus, 22 environmental Staph. aureus, 30 clinical Staph. epidermidis and 12 environmental Staph. epidermidis to methicillin and vancomycin from teaching hospitals in Nigeria.
Material and Methods: The Staphylococcus species were identified and confirmed by gram-positive cocci morphology, catalase-positive reaction, tested for mannitol salt fermentation and DNase production. The organisms were confirmed to be Staph. aureus and Staph. epidermidis by the tube coagulase test. The antibiotics susceptibility patterns were determined both by overnight broth-micro-dilution and agar disk diffusion methods.
Results: The isolates were resistant to ampicillin, followed by penicillin, tetracycline, erythromycin and gentamicin but to a lesser extent were sensitive to ciprofloxacin. All the multi-drug resistant (MDR) Staphylococcus species were 100% sensitive to vancomycin and methicillin with a minimum inhibition concentration (MIC) breakpoint < 4µg/ml to vancomycin and MIC < 5µg/ml to methicillin on Mueller Hinton agar supplemented with 2%NaCl.
Conclusion: The results indicated that methicillin and vancomycin are still very potent antibiotics against staphylococcal infections in Nigeria.


Keywords: MDR Staphylococcus, methicillin and vancomycin

Sudan Journal of Medical Sciences Vol. 2 (4) 2007: pp. 257-262