Activity of cephalosporins against methicillin-resistant coagulase-negative staphylococci.

Using a dilution method (37 degrees C, 42 h), six of ten methicillin-resistant strains of coagulase-negative staphylococci were found to be resistant to cephalothin. Of 20 variations in the method for detection of resistance to methicillin and cephalothin, broth dilution tests at 30 degrees C for 42 h were the most sensitive. Differences are explained by low percentages of cephalothin-resistant clones in methicillin-resistant strains.