[Resistance of methicillin-resistant staphylococci to new cephalosporin antibiotics (author's transl)].

The activity of new cephalosporins was examined using 60 coagulase-positive, methicillin-resistant staphylococcus strains and compared with that of cefalothin, methicillin and oxacillin. The results showed cefamandole to be the most effective of the new cephalosporins, its activity being comparable to that of cefalothin; cefoxitin was comparable to oxacillin and methicillin. Cefuroxime, cefoperazone, cefotaxime and moxalactam were ineffective against staphylococci. Varying degrees of hetero-resistance to all antibiotics of the beta-lactam group were found. A synergistic effect was obtained with subinhibitory concentrations of cefoxitin in combination with cefamandole or cefuroxime. In an investigation of routine determination of methicillin resistance by the diffusion method, it was found that resistance can be ascertained reliably with the technique of both the German Industrial Norm (DIN), which has not yet been officially introduced, and the technique of the American Food and Drug Administration (FDA) using a methicillin disc (5 microgram) or an oxacillin disc (1 microgram) and an incubation temperature of 35 degree C. The possibility of using beta-lactam antibiotics in infections caused by methicillin-resistant staphylococci is discussed.