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

The frequencies of isolation and susceptibilities to antimicrobial agents were investigated on 704 bacterial strains isolated from patients with urinary tract infections (UTIs) in 11 hospitals during the period of June 1995 to May 1996. Of the above bacterial isolates, Gram-positive bacteria accounted for 29.8% and a majority of them were Enterococcus faecalis. Gram-negative bacteria accounted for 70.2% and most of them were Escherichia coli. Susceptibilities of several isolated bacteria to antimicrobial agents were as followed;<BR>1. Enterococcus faecalis Ampicillin (ABPC) and imipenem (IPM) showed the highest activities against E. faecalis isolated from patients with UTIs. The MIC₉₀s of them were 1μg/ml. Vancomycin (VCM) and piperacillin (μ) were also active with the MIC₉₀s of 2μg/ml and 4μg/ml, respectively. The others had low activities with the MIC₉₀S of 16μg/ml or above.<BR>2. Staphylococcus aureus including MRSA VCM showed the highest activities against S. aureus isolated from patients with UTIs. Its MIC₉₀ was 1μg/ml against both S. aureus and MRSA. Arbekacin (ABK) was also active with the MIC₉₀ of 2μg/ml. The others except minocycline (MINO) had very low activities with the MIC₉₀s of 64μg/ml or above.<BR>3. Staphylococcus epidermidis ABK and MINO showed the strongest activities against S. epidermidis isolated from patients with UTIs. The MIC₉₀s of them were 0.25μg/ml. VCM was also active with the MIC₉₀ of 1μg/ml. The MIC₉₀s of cephems ranged from 2μg/ml to 16μg/ml in 1994, but they ranged from 8μg/ml to 128μg/ml in 1995. These results indicated that some resistances existed among S. epidermidis to cephems.<BR>4. Streptococcus agalactiae All drugs except gentamicin (GM) were active against S. agalactiae. ABPC, cefmenoxime (CMX), IPM, erythromycin (EM), clindamycin (CLDM) and clarithromycin (CAM) showed the highest activities. The MICs for all strains were lower than 0.125μg/ml. The MIC₉₀s of the others were 2μg/ml or below.<BR>5. Citrobacter freundii IPM showed the highest activity against C. freundii isolated from patients with UTIs. Its MIC₉₀ was 1μg/ml. GM was also active with the MIC₉₀ of 2μg/ml. Cefpirome (CPR), cefozopran (CZOP) and amikacin (AMK) were also active with the MIC₉₀s of 4μg/ml. Penicillins and cephems except CMX, CPR and CZOP showed low activities with MIC₉₀s of 256μg/ml or above.<BR>6. Enterobacter cloacae IPM showed the highest activity against E. cloacae. The MICs for all strains were equal to or lower than 1μg/ml. MINO and tosufloxacin (TFLX) were also active with the MIC₉₀s of 8μg/ml.Penicillins and cephems except CPR and CZOP showed lower activities with the MIC₉₀s of 256μg/250(32) THE JAPANESE JOURNAL OF ANTIBIOTICS 50-3 Mar. 1997 ml or above.<BR>7. Escherichia coli Most of antimicrobial agents were active against E. coll. Particularly CPR, CZOP and IPM showed the highest activities against E. coll. The MICs for all strains were equal to or lower than 0.5μg/ml. CMX and TFLX were also active with the MIC₉₀s of 0.125μg/ml or below. Penicillins were slightly active with MIC₉₀s of 128μg/ml or above.<BR>8. Klebsiella pneumoniae K. pneumoniae was susceptible to all drugs except penicillins, with MIC₉₀s of 2μg/ml or below. Carumonam (CRMN) had the strongest activity against K. pneumoniae, the MICs for all strains were equal to or lower than 0.125μg/ml. Comparing with the result of 1994, the sensitivities of K. pneumoniae against all drugs had obviously changed into a better state. For example, the MIC₉₀s of cephems ranged from 0.25μg/ml to 16μg/ml in 1994, but they were all lower than 2μg/ml in 1995.<BR>9. Proteus mirabilis P. mirabilis was susceptible to a majority of drugs.