[Comparative studies of antimicrobial agents against causative organisms isolated from urinary tract infections (1983). III. Secular changes in susceptibility].

The in vitro antimicrobial activities of antibiotics against causative pathogens isolated from patients with urinary tract infections (UTI) in the 8 institutions in Japan during the period from 1980 to 1983 were compared. A number of new beta-lactam antibiotics with broad spectrum of activity have become available for clinical use in recent years. Some of them, in particular so-called third generation cephems, are reported to be responsible for developing microbial-cross resistance to multiple beta-lactam antibiotics. We have been making survey in recent years to explore changes in susceptibility to various antimicrobial agents of clinical isolates. All bacterial isolates from clinical specimens were submitted to the Department of Clinical Pathology, Juntendo University School of Medicine, where they were tested for antimicrobial susceptibility with MIC 2000 apparatus. Of all pathogens from patients with simple UTI, the majority of the isolates was E. coli and Klebsiella spp. In cases of complicated UTI, on the other hand, Pseudomonas spp. were most frequent, followed in order by Proteus spp., Klebsiella spp., Serratia spp., Citrobacter spp. and E. coli. Conspicuous changes in antimicrobial activity of antibiotics against E. coli and Klebsiella spp. from simple UTI have not been found in our survey. Against strains of Citrobacter spp., even the third generation cephems proved to be not remarkably active and there was a significant decrease in susceptibility of isolates to the drugs test-showed MIC values of 50 micrograms/ml and the proportion increased to 50% (22/44) with isolates obtained in 1982. The antimicrobial activity of cefsulodin and gentamicin against P. aeruginosa was decreased in 1982 compared with that in 1980 and 1981. However, resistant strains were slightly more frequent with gentamicin. In 1983, the antimicrobial activity of third generation cephems against Serratia spp. was significantly reduced from that in 1982.