[Study on bacterial infection by the investigation of antimicrobial susceptibility of various clinical isolates. III. Comparison of drug susceptibility between the isolates from the materials of out- and in-patients, and among the isolates from the materials of different hospital units].
Antimicrobial agents susceptibility of 42, 940 strains of clinical isolates (from 1979 to 1986) were investigated and the data were analyzed on the basis of the sources of isolates; materials from in- and out-patients or from the different hospital units. Bacteria studied were limited to the species of which isolates were 100 or more during 1979 to 1986. The following results were obtained. i) When the antibiotic susceptibility of the isolates from the out-patient-materials were compared with that from the in-patient-materials, the following 13 bacterial species isolated from the former source were found to be more susceptible to antibiotics than that of the latter. These were S. aureus, S. epidermidis, E. coli, Citrobacter sp., Klebsiella sp., Serratia sp., P. vulgaris, P. rettgeri, M. morganii, P. aeruginosa, P. putida, S. sonnei and Salmonella sp.. ii) The frequency of isolation and their antibiotic susceptibility of S. aureus, Enterobacter sp. and P. aeruginosa from both the in- and out-patients were comparable through 1979. However, S. aureus isolated from the in-patient-materials tended to show increased antibiotic resistance since 1983. This is probably due to the frequent use of the 3rd generation cephalosporins. iii) Comparison of the antibiotic susceptibility of the isolates from the different hospital units showed that the resistant strains were more frequently isolated in the materials from the urology unit and the susceptible strains were more frequently isolated in the materials from the infectious diseases unit. iv) Antibiotic resistant S. aureus and P. aeruginosa increased abruptly since 1983 in the materials from the surgery and urology unit, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)