IN VITRO SYNERGIC EFFECTS OF BETALACTAMS AND AMINOGLYCOSIDES COMBINATIONS ON STAPHYLOCOCCUS GENUS STRAINS

Abstract: The association of antibiotics are often used in therapy in order to enhance the efficieny and also to minimize the development of bacterial resistance. Generally; the combinations have in their structure antibiotics that present; one to other; the phenomenon of synergism. In order to observe the synergism between antibiotics; this research studied combinations of betalactam antibiotics and aminoglycosides; that were efficient on pathogens from Staphylococcus genus. The antibacterial susceptibility was tested through dilution method; that was applied both for the combination of antibiotics and also for the antibiotics alone. The interaction between antibiotics was appreciated by calculating the fractional inhibitory concentration and by interpreting the results in accordance to CF Referral Center for Susceptibility & Synergy Studies; Columbia University; New York. Amoxicillin-gentamicin combination had synergic effects in a percentage of 71;43 %; addition being observed for 28;57 % strains. In a lower percentage was noted synergism for the combination ceftiofur-gentamicin – 57;14 % – but the addition phenomenon was in a higher percentage – 42;86 %. So; we recommend both these combination; because of the synergic or additive activities of the antibiotics; with the specification that it is better to use amoxicillin-gentamicin association than the combination ceftiofur-gentamicin; for Staphylococcus strains