COMPARATIVE STUDIES ON ACTIVITIES OF ANTIMICROBIAL AGENTS AGAINST CAUSATIVE ORGANISMS ISOLATED FROM PATIENTS WITH URINARY TRACT INFECTIONS (1995)

III. DIFFERENCES IN SUSCEPTIBILITIES FROM PREVIOUS YEARS

Abstract

Susceptibilities to various antimicrobial agents were examined for Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Klebsiella spp. and Pseudomonas aeruginosa that were isolated from patients with urinary tract infections (UTIs) in 11 hospitals during June, 1995 through May, 1996, and the results were compared with those obtained during the same period in earlier years.
1. Macrolide resistant E. faecalis isolated from uncomplicated UTIs during the latest study period appeared to have increased compared to those in previous study periods. More than 50% of the isolated E. faecalis during the latest study period were resistant to macrolide antibiotics, for the first time in our history.
2. No obvious changes were observed through the years for susceptibilities of S. aureus to various antimicrobial agents. Vancomycin (VCM) showed the highest activity against S. aureus, with MICs below 2μg/ml or below.
3. Among E. coli strains, those with low susceptibilities to quinolones appeared to have increased over the years with MIC₉₀ changed from between 0.125μg/ml or below and 0.5μg/ml in the 1989-1990 period to between 8μg/ml and 128μg/ml in the latest study period.
4. Klebsiella spp. showed higher resistance to most antimicrobial agents during periods of 1993-1994 and 1994-1995, but somewhat lower resistance during period of 1995-1996. No resistant Klebsiella spp. were detected from uncomplicated UTIs during the latest study period.
5. Among P. aeruginosa isolates from complicated UTIs, resistance isolates to gentamicin appeared to be increasing over the years. Resistant strains to quinolones were isolated at lower frequencies during periods of 1991-1994, but higher frequency was observed in the latest period, and MIC₅₀s were between 0.5 and 4μg/ml during 1991-1994, but were 16-32μg/ml during 1995-1996.
These susceptibility changes should be utilized in determining clinical treatments.