Comparative Evaluation of In-Vitro Activity of Amoxicillin- Cloxacillin Combination against Clinical Isolates of Staphylococcus aureus.

Abstract

Literature is replete with numerous reports of the high rate of emergence of resistant strains of staphylococcus aureus with decreased susceptibility to available penicillins. The strong need for the design and development of newer antibiotics and the re-engineering of existing ones with a view to limiting antibiotic resistance has been suggested by many researchers. The objective of this study was to explore and evaluate the susceptibility pattern of amoxicillin- cloxacillin combination (amoxiclox) against 69 clinical isolates of S. aureus. The methods adopted included disc diffusion, MIC and time-kill studies.
Our results showed that only one of the 69 isolates demonstrated intermediate resistance to Amoxiclox. None of the isolates showed tolerance to either Amoxiclox or ciprofloxacin. However, all ciprofloxacin- resistant isolates were sensitive to Amoxiclox and highly resistant to Ampicillin-Cloxacillin combination. Killing curves on two isolates showed synergy in amoxicillin-cloxacillin combination. The valuable potentials of Amoxicillin- cloxacillin combination in the treatment of staphylococcal infections are indicated compared to other drugs used in this study.


Keywords: Amoxicillin- Cloxacillin, In-Vitro Activity, Synergy, Staphylococcus aureus.

NQJHM Vol. 14 (2) 2004: pp. 200-205