Sr. Norris et al., PRODUCTION OF A-VARIANT AND C-VARIANT OF STAPHYLOCOCCAL BETA-LACTAMASE BY METHICILLIN-RESISTANT STRAINS OF STAPHYLOCOCCUS-AUREUS, Antimicrobial agents and chemotherapy, 38(7), 1994, pp. 1649-1650
Most methicillin-resistant Staphylococcus aureus (MRSA) strains produc
e beta-lactamase. To determine whether this enzyme(s) is identical to
one or more of the four beta-lactamases produced by methicillin-suscep
tible strains, the beta-lactamases of 50 MRSA isolates were typed by u
sing substrate profile analysis. Forty type A, no type B, ten type C,
and no type D beta-lactamase-producing strains mere identified. The be
ta-lactamase inhibitor sulbactam reduced the MICs of beta-lactamase-la
bile antibiotics, including ampicillin, penicillin G, and cefazolin, f
or type A and type C MRSA strains.