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, β-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 β-lactamase producing strains were as follows:methicillinsusceptible 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 β-lactamases produced by these strains were mostly penicillinase or enzyme of similar that. 2. Antimicrobial activities of CVA/AMPC against β-lactamase producing strains were stronger than those of AMPC, and MIC90 of CVA/AMPC against benzylpenicillin(PCG)-insensitive or resistant Streptococcus pneumoniaewas lower than those of sultamicillin, cefaclor and cefpodoxime. 3. CVA showed strong β-lactamase inhibitory effect againstM.(B.)catarrhalis of direct and indirect pathogenicity. We can expect CVA/AMPC to negate or decrease the influence of indirect pathogenicity.