dibekacin and flomoxef

MICs of various antibacterial agents against methicillin-resistant Staphylococcus aureus (MRSA) were measured. Furthermore, we evaluated the effects of combinations of antibacterial agents against MRSA in vitro. In 24 cases out of 37, in which MRSA was isolated from inpatients, other microorganisms, such as Candida spp., Entrococcus spp., and Pseudomonas aeruginosa, were simultaneously isolated. From the results of minimum inhibitory concentrations (MICs), obtained from micro broth-dilution method, of various antibacterial agents against MRSA, range of MICs of arbekacin (ABK), vancomycin (VCM) and teicoplanin (TEIC) were < or = 0.25-4.0, 0.5-1.0 and 0.25-4.0 micrograms/ml respectively, and no strains of MRSA showed resistance to ABK, VCM and TEIC, so that we concluded that these three antibacterial agents were effective for MRSA infection. On the in vitro study of combination-effect of antibacterial agents, significant synergistic effects were achieved in the combination of VCM and flomoxef (FMOX) (Synergism rate was 97.3%) or VCM and imipenem (IPM) (Synergism rate was 97.2%). From the results that the fractional inhibitory concentration index in the combination of VCM with IPM was smaller than that with FMOX and that P. aeruginosa or Enterococcus spp. were simultaneously isolated in high frequency in the MRSA-isolated cases, we thought that the combination of VCM with IPM is more useful, because IPM is effective against P. aeruginosa but FMOX is not.

Topics: Aminoglycosides; Anti-Bacterial Agents; Cephalosporins; Dibekacin; Drug Resistance, Microbial; Drug Therapy, Combination; Humans; Imipenem; Methicillin Resistance; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Staphylococcus aureus; Teicoplanin; Vancomycin

Combination effects were studied with arbekacin (ABK) and beta-lactam antibiotics including imipenem/cilastatin (IPM/CS), flomoxef (FMOX), and cefotiam (CTM) for bactericidal activities, post-antibiotic effects (PAE's) and bactericidal activities of beta-lactam antibiotics after removal of ABK using methicillin-resistant Staphylococcus aureus (MRSA) strain 1936. The following results were obtained. 1. When ABK was administered in combination with IPM/CS, FMOX or CTM against MRSA strain 1936, low FIC index was not obtained. 2. Higher bactericidal activity was observed when ABK was given before beta-lactam than when beta-lactam was given before ABK. 3. Combination of ABK and each of beta-lactam antibiotic led a longer PAE than ABK alone. 4. When each beta-lactam antibiotic was administered after a treatment and removal of ABK, greater bactericidal activity and growth inhibition were observed than when administered each beta-lactam alone. These findings basically demonstrated that ABK was effectively bactericidal against MRSA when administered in combination with beta-lactam antibiotic such as IPM/CS, FMOX or CTM, even when the FIC index did not indicate a favorable effect.

Topics: Aminoglycosides; Anti-Bacterial Agents; Cefotiam; Cephalosporins; Cilastatin; Dibekacin; Drug Therapy, Combination; Imipenem; Methicillin Resistance; Microbial Sensitivity Tests; Staphylococcus aureus

We determined the in vitro activities of arbekacin in combination with other antibiotics against 96 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). Efficacies were evaluated by comparing frequencies of susceptible strains at concentrations of antibiotics present in serum 3 hours after intravenous administration of recommended dosages with those obtained with addition of 1 or 2 micrograms/ml of arbekacin. The addition of arbekacin significantly increased the antibacterial activities of cefotiam, cefuzonam, flomoxef and fosfomycin, but had no effect on the activity of either imipenem or minocycline. Arbekacin in combination with fosfomycin was found to have the greatest activity against MRSA among combinations tested. In addition, arbekacin had excellent antimicrobial activity against Pseudomonas aeruginosa, compared to other anti-pseudomonal agents such as piperacillin, ceftazidime and imipenem.

Topics: Aminoglycosides; Anti-Bacterial Agents; Cefotiam; Ceftizoxime; Cephalosporins; Dibekacin; Drug Therapy, Combination; Fosfomycin; Humans; Methicillin Resistance; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Staphylococcus aureus

Out of 110 strains of Staphylococcus aureus isolated from 1985 to 1990, isolation rate of methicillin-resistant S. aureus (MRSA) was investigated. Nineteen strains of 59 S. aureus from outpatients and 20 strains of 51 S. aureus from inpatients were determined as MRSA. Isolation frequency of MRSA from inpatients was increasing in the recent two years. Coagulase type, enterotoxin type and production of toxic shock syndrome toxin-1 (TSST-1) were examined in 22 strains of MRSA. Coagulase type II (86%), enterotoxin type C (68%) and TSST-1 positive strain was most dominant. Susceptibility of MRSA to 4 antimicrobial agents were measured, MRSA were sensitive to vancomycin (VCM), arbekacin (ABK) and minocycline, but resistant to flomoxef. Thirty-four patients from whom MRSA was isolated including 20 patients from urine, 13 from pus and 1 from blood, were analyzed clinically. Pyuria was not recognized in some cases in whom MRSA was isolated from their urine. Concomitant polymicrobial infection was frequently noted in those patients with MRSA in their urinary tract. These facts show that the pathogenic role of MRSA in the urinary tract infection was not significant. On the other hand, when MRSA was isolated from pus or blood, serious infections could be caused by MRSA, especially in compromised host. Regarding the treatment in these cases, administration of VCM or ABK was though to be necessary.

Topics: Aminoglycosides; Anti-Bacterial Agents; Cephalosporins; Dibekacin; Humans; Immunocompromised Host; Methicillin Resistance; Minocycline; Serotyping; Staphylococcus aureus; Urologic Diseases; Vancomycin

Antibacterial effects of combination use of arbekacin (ABK) with cefmetazole (CMZ) or flomoxef (FMOX) were evaluated against methicillin-resistant Staphylococcus aureus (MRSA) and the following results were obtained. 1. Antibacterial effects of combinations of ABK with CMZ and with FMOX were equally potent against MRSA at clinically expected 1 MIC of ABK in blood. However, at a sub MIC of ABK different effects were observed between the 2 combinations. The former combination was slightly less effective than the latter. 2. In either combination the potency of the antibacterial activity was less dependent on the concentration of CMZ or FMOX, but was strongly dependent on ABK concentrations. These results suggest that antibacterial effects of the combinations were highly dependent on antibacterial potency and concentration of ABK as previously reported for combinations of ABK with other drugs. 3. It appears that the antibacterial activity of the combination of the sub MIC of ABK with a beta-lactam is an important point in considering the effectiveness of a combination therapy.

Topics: Aminoglycosides; Anti-Bacterial Agents; Cefmetazole; Cephalosporins; Dibekacin; Drug Resistance, Microbial; Drug Synergism; Methicillin Resistance; Staphylococcus aureus