ABSTRACT
Staphylococcus aureus is one of the most important causes of nosocomial infections and most clinical isolates are multidrug resistant. Resistance to beta-lactam antibiotics is most often due to bacterial beta-lactamase production. Characterization of beta-lactamases is important for choosing appropriate antibiotic therapy. Thirty methicillin resistant Staphylococcus aureus [MRSA] were identified by standard biochemical methods. Antibacterial susceptibility to 9 beta-lactam antibiotics was determined. Beta-lactamase production was shown in all isolates using the colony iodometric test and nitrocefin discs. Beta-lactamase typing was carried out by measuring the relative substrate hydrolysis rates. The MRSA isolates were resistant to the majority of beta-lactam antibiotics. The results showed that 90% of the isolates displayed type A substrate hydrolysis profile of beta-lactamase. The alarming high level of resistance to beta-lactam antibiotics including methicillin and 3[rd] generation beta-lactams show the need for extensive studies on alternative treatment protocols and use of new drugs