COMPARATIVE STUDIES ON ACTIVITIES OF ANTIMICROBIAL AGENTS AGAINST CAUSATIVE ORGANISMS ISOLATED FROM URINARY TRACT INFECTIONS (1985)

II. BACKGROUND OF PATIENTS

Abstract

We have investigated relationships between patients´ backgrounds and isolates from urinary tract infections in reference to various conditions, such as sexes, age distribution by sex, species of causative organisms by sex, age distribution according to species and types of infections, species and infections before and after treatment with antibacterial agents, and species and detected places. As for the relationship between sexes and types of infections, although simple urinary tract infections were consistently found at about 20% in men and at about 80% in women between 1981 and 1983, these infections were seen at 24.4% in men and at 75.6% in women in 1984, and at 26.6% and at 73.4% in 1985, indicating slight decreases in the ratio of women.By contrast, complex urinary tract infections were found in men at about 60-70% from 1981 up to 1985, regardless of the presence or absence of indwelling catheter. There were no noticeable changes according to age during this 5-year period in incidences of infections including simple urinary tract infection and complex urinary tract infection with or without indwelling catheter. Thus, backgrounds of patients with urinary tract infections, including sex, age and simple or complex infections, were fairly consistent throughout this period, while there were relatively large changes in species of isolates. Enterococcus faecalis was isolated at about 8% of both men and women in 1982 and 1983, but its isolation rates were increased to 22.5% of men and 17.9% of women in 1984. In 1985 this species was isolated in 14.9% of men and 7.6% of women, and in 11.2% of all patients. Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus spp. and Enterococcus spp. were detected at rates of 3.2%, 8.1%, 0.7% and 1.0%, respectively, and 24.2% of isolated strains were Gram-positive organisms. When species of isolates before treatment with antibacterial agents and their isolation rates were analyzed, it was found that the isolation rate of E. faecalis increased dramatically in 1983, and that this tendency was still seen in 1984. The isolation rate of Gram-positive organisms was 25% in 1984 and 24.3% in 1985. Escherichia coli was consistently isolated at about 40%, but, as far as simple urinary tract infections are concerned, its isolation rate decreased by about 10% in 1985, compared to 1982 and 1983. These results suggested that causative organisms for simple urinary tract infections became similar to those for complex urinary tract infections. In other words, isolates obtained from complex urinary tract infections before treatment were similar to those of simple infections. When antibacterial agents were administered for more than 8 days, most of urinary tract infections from which bacteria were isolated were of complex types. Pseudomonas aeruginosa and Serratia spp. were found slightly more in cases without indwelling catheter than those cases having indwelling catheter. In cases with indwelling catheter, S. aureus was isolated at 4.8% in 1984, and its isolation rate increased to 10.0% in 1985. Although about 90% of causative organisms for simple urinary tract infections had been thought to be E. coli, the isolation rate of E. coli among our cases with simple urinary tract infections was below 50% and has been gradually decreasing year by year. E. coli, as a causative organism for simple urinary tract infections, has been replaced by other species which had been considered as causative organisms for complex urinary tract infections, resulting in more complication of urinary tract infections. Increases in detection rate of Gram-positive organisms, especially S. aureus and E. faecalis, seemed to indicate the presence of causal relation to drug treatment. Therefore, it was thought that unbalanced uses of limited types of drugs should be avoided, although this point requires a further study.