COMPARATIVE STUDIES ON ACTIVITIES OF ANTIMICROBIAL AGENTS AGAINST CAUSATIVE ORGANISMS ISOLATED FROM URINARY TRACT INFECTIONS (1986)

I. SUSCEPTIBILITY DISTRIBUTION

Abstract

Susceptibilities to various antibacterial and antibiotic agents of bacterial strains isolated from urinary tract infections at 8 hospitals in Japan from July to October in 1986 are summarized as follows.
1. Enterococcus faecalis was susceptible to sulfamethoxazole/trimethoprim (ST) and imipenem (IPM) with MIC₉₀S of 0.78 and 1.56 μg/ml. Minocycline had the strongest activity against Staphylococcus aureus; the MICs for all strains tested were lower than 0.39 μg/ml. The MIC₈₀S of dicloxacillin, and arbekacin (HBK) were 0.20 and 0.78 μg/ml, respectively. Among the cephems, the MIC₈₀ of flomoxef was 25 μg/ml, whereas those of cefmenoxime (CMX) and cefotiam (CTM) were 50 μg/ml.
2. Escherichia coli was most susceptible to ofloxacin (OFLX) among the oral antibacterial and antibiotic agents tested. OFLX showed the minimum inhibitory concentration against 90% (MIC₉₀) of the 274 strains of E. coli tested to be lower than 0.10 μg/ml. The antibacterial activities of the third generation cephems such as CMX and latamoxef (LMOX) were the strongest among the injectable antibiotics tested. The MIC₉₀S of CMX and LMOX were lower than 0.10 and 0.20 μg/ml, respectively. CTM and cefmetazole, the second generation cephems, were also highly active against E. coli with MIC₉₀S of 0.39 and 1.56 μg/ml, respectively.
3. Among the oral antibacterial and antibiotic agents tested, OFLX was the most active against Klebsiella pneumoniae. Its MIC₉₀ was 0.78 μg/ml. Among the injectable antibiotics tested, CMX was the strongest with an MIC₉₀ of 0.20 μg/ml; MIC₉₀ of CTM and LMOX were 0.39 μg/ml.
4. The tested antibacterial and antibiotic agents were generally less active against Citrobacter freundii than against other bacteria. The MIC₈₀ of OFLX was 0.39 μg/ml. Gentamicin (GM) and ST were slightly active against C. freundii. Among the cephems, CMX had the MIC₈₀ of 25 μg/ml.
5. Enterobacter cloacae was less susceptible to the cephems tested. OFLX, GM, and mecillinam were active against this bacteria with MIC₈₀S of 0.78, 0.78 and 1.56 μg/ml, respectively.
6. Among the oral antibacterial and antibiotic agents and penicillins examined, piperacillin (PIPC) was the most active against Proteus mirabilis. Its MIC₉₀ was 0.39 μg/ml. Those of sulbenicillin, cefaclor, ampicillin, OFLX, and ST were 0.78, 0.78, 1.56, 3.13 and 3.13 μg/ml, respectively. CMX was highly active against P. mirabilis with an MIC₉₀ of ≤0.10 μg/ml; LMOX followed with an MIC₉₀ of 0.20 μg/ml among the injectable antibiotics tested. CTM was also active against this bacterium; the MIC₉₀ was 0.39 μg/ml.
7. The antibacterial and antibiotic agents were generally only slightly active against Proteus vulgaris. The MIC₈₀S of LMOX and CMX were 0.78 and 6.25 μg/ml, respectively.
8. Morganella morganii was only weakly susceptible to antibacterial and antibiotic agents except the third generation cephalosporins. The MIC₈₀S of CMX and LMOX were 0.78 μg/ml.
9. The antibacterial and antibiotic agents were generally less active against Serratia marcescens than against other bacteria. The MIC₈₀S of OFLX and CMX were 12.5 and 25 μg/ml, respectively.
10. Pseudomonas aeruginosa was isolated frequently from urinary tract infections. Ciprofloxacin (CPFX) and norfloxacin (NFLX), new quinolones, were highly active against this bacterium with MIC₅₀S of 0.20 and 0.78 μg/ml, respectively. The MIC₅₀S of cefsulodin, IPM, ceftazidime, and tobramycin were all 1.56 μg/ml and those of PIPC, cefoperazone, carumonam and various aminoglycosides, such as micronomicin, dibekacin, sisomicin, GM and HBK, ranged from 3.13 μg/ml to 6.25 μg/ml.