title: Divergent disk susceptibility of coagulase-negative staphylococci to penicillinase-resistant penicillins and augmentin (amoxycillin/clavulanic acid).
abstract: 30 representative intrinsically penicillin-resistant coagulase-negative staphylococcal (CONS) isolates yielded discrepant agar disk diffusion test (Bauer-Kirby) results for augmentin. Clavulanic acid (2.5 micrograms/ml) enhanced the activity of amoxycillin from 8- to greater than or equal to 128-fold (mean = 26-fold); MICs of amoxycillin (combined with 2.5 micrograms/ml clavulanate) ranged from 1-16 (mean = 3) micrograms/ml. It is recommended that clinical microbiology laboratories withhold 'susceptible' augmentin disk tests results from their reports regarding intrinsically penicillin-resistant CONS isolates. No such discrepancies were encountered among clinical isolates of Staphylococcus aureus.
mesh_terms: D000658:Amoxicillin / Q000494:pharmacology*; D019980:Amoxicillin-Potassium Clavulanate Combination; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002969:Clavulanic Acids / Q000494:pharmacology*; D003030:Coagulase / Q000032:analysis*; D004338:Drug Combinations / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D010405:Penicillinase / Q000378:metabolism; D010406:Penicillins / Q000378:metabolism / Q000494:pharmacology*; D013210:Staphylococcus / Q000187:drug effects* / Q000201:enzymology
chemical_list: D000900:Anti-Bacterial Agents; D002969:Clavulanic Acids; D003030:Coagulase; D004338:Drug Combinations; D010406:Penicillins; D019980:Amoxicillin-Potassium Clavulanate Combination; D000658:Amoxicillin; D010405:Penicillinase