[Antimicrobial activities of clavulanic acid/amoxicillin against freshly isolated clinical strains from outpatients].

In order to investigate antimicrobial activities of clavulanic acid/amoxicillin (CVA/AMPC) against freshly isolated clinical strains obtained in 1995, beta-lactamase activities and minimum inhibitory concentration (MICs) were determined including those of the control drugs. The results are summarized as follows; 1. Detection frequencies of beta-lactamase producing strains were as follows: methicillin-susceptible Staphylococcus aureus subsp. aureus (MSSA, 90.0%), Haemophilus influenzae (22.0%), Moraxella subgenus Branhamella catarrhalis (100.0%), Escherichia coli (100.0%), Klebsiella pneumoniae subsp. pneumoniae (100.0%) and Neisseria gonorrhoeae (14.0%). It appeared that beta-lactamases produced by these strains were mostly penicillinase or enzyme of similar that. 2. Antimicrobial activities of CVA/AMPC against beta-lactamase producing strains were stronger than those of AMPC, and MIC90 of CVA/AMPC against benzylpenicillin (PCG)-insensitive or resistant Streptococcus pneumoniae was lower than those of sultamicillin, cefaclor and cefpodoxime. 3. CVA showed strong beta-lactamase inhibitory effect against M.(B.) catarrhalis of direct and indirect pathogenicity. We can expect CVA/AMPC to negate or decrease the influence of indirect pathogenicity.