ANTIMICROBIAL ACTIVITIES OF PIPERACILLIN AGAINST FRESH CLINICALLY ISOLATED STRAINS

In order to evaluate the antimicrobial activity of piperacillin (PIPC), along with control agents, minimum inhibitory concentrations (MIC's) were determined against fresh clinically isolated strains from January to June, 1994. 1. The MIC70's of PIPC against major strains were approximately equal to those reported in the mid 1980s. 2. Strains for the study were supplied in approximately equal numbers from communityacquired hospitals and general hospitals. The ratios of bacteria resistant to β-lactams including PIPC were low in the former group and high in the latter. 3. “New types of, β-lactam-resistant strains” which did not exist in mid 1980s but found at this time included benzylpenicillin (PCG)-insensitive Streptococcus pneumoniae, PCG-resistant S. pneumoniae, cephems-resistant Escherichia coli and β-lactamase producing Prevotella spp. These bacteria were also found among strains obtained from community-acquired hospitals.