Resistance of Staphylococcus aureus to methicillin (MRSA) is a serious clinical problem. In this paper, the relationship between the induction of penicillin binding protein (PBP-2') and selection of highly-resistant MRSA by cefminox (CMNX) and other β-lactam compounds.
1. CMNX and ceftizoxime (CZX) did not have any bactericidal activity against 100 MRSA strains in physiological concentrations. However, flomoxef (FMOX) and imipenem/cilastatin (IPM/CS) showed good antibacterial activity against 7% and 20% of MRSA strains, respectively.
2. The frequency of MRSA Y-782 strains against resistant to β-lactam compounds was high in IPM/CS and FMOX-treated cultures, antibiotics, which showed good bacteriadal effects against MRSA Y-782. In contrast, the frequency of MRSA Y-112 resistant strains was low in IPM/CS and FMOX-treated cultures which had no effects on MRSA Y-112 bacteria.
3. The MIC of CMNX and CZX did not change when β-lactam compounds were applied to MRSA Y-782 strains at physiological concentrations. However, the MIC increased by up to 32-fold time in the case of FMOX and IPM/CS with some strains.
4. CMNX induced PBP-2' just like other β-lactam compounds when MRSA Y-112 strains were cultured in the presence of low drug concentrations. However, when this bacteria was returned to non-drug containing medium, the amount of PBP-2' decreased, showing a similar PBP pattern to that before the drug was added.

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We experienced a premature baby with multiple congenital anomalies, who became infected withPseudomonas aeruginosa and died of septicemia and disseminated intravascular coagulation. ThisP. aeruginosa was proven to be a very rare isolate resistant to all 15 antibiotics, including piperacillin, ceftazidime, cefepime, cefoperazone/sulbactam, panipenem, aztreonam, amikacin, levofloxacin and fosfomycin, utilized in this case. In vitro evaluation of the fractional inhibitory concentration index indicated that administration of an amikacin and aztreonam combination would be the optimal choice of treatment for infection with this multidrug resistant P. aeruginosa.

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The efficacy, safety and usefulness of ciprofloxacin (CPFX), in fine granule form, were investigated in a clinical study involving treatment of patients with acute tonsillitis, acute pharyngolaryngitis (referred to as Group I hereafter), chronic bronchitis and infectious bronchiectasis (referred to as Group II hereafter) among respiratory tract infections. A 200mg dose of the test drug (as CPFX) was orally given t. i. d. to the patients after each meal. Patients in Group I received the test drug for 7 days or less, in principle, and those in Group II for 2 weeks or less. A total of 41 cases were enrolled in this study: There were 4 cases with acute tonsillitis, 10 with acute pharyngolaryngitis, for a total of 14 cases in Group I. There were 14 cases with chronic bronchitis and 13 with infectious bronchiectasis, for a total of 27 in Group II. The clinical efficacy rate was 89.2%(33/37 cases), being 100%(13/13 cases) for Group I and 83.3%(20/24 cases) for Group II. The elimination rate of causative organisms was 73.1%(19/26 strains), in terms of bacteriological efficacy. Side effects were noted in 4 cases (9.8%) with 6 events all involving gastrointestinal symptoms, all of which were mild, and disappeared after completion of the treatment or drug discontinuation. Among abnormal laboratory findings, GPT was elevated in 2 cases (5.4%). In the evaluation of overall drug safety on 86.8%(33/38 cases) safety rate was obtained, which produced an 81.1%(30/37 cases) usefulness rate. Therefore, the present study confirmed good effectiveness and safety of CPFX, in fine granule form, for the treatment of respiratory tract infections.

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Patients with hematological malignancies, who were clinically suspected of having sepsis after developing granulocytopenia and a fever of 38°C or higher following anti-cancer chemotherapy, were divided into Group A and Group B by an envelope method. Group A received antibacterial agents (piperacillin: PIPC+isepamicin: ISP) and an immunoglobulin preparation (Polyglobin N^®) simultaneously. Group B received antibacterial agents (PIPC+ISP) first and an immunoglobulin preparation 4 days later. The clinical courses of both groups were compared. There were no significant differences between Group A (10 cases) and Group B (11 cases) in underlying diseases and leukocyte count, granulocyte count, CRP or use of CSF preparations at the fever onset. In Group A, decline of fever and improvement of CRP were significantly quicker compared to those in Group B. Recovery of the leukocyte count was also significantly faster in Group A than in Group B. The treatment period with the antibacterial agents was significantly shortened in Group A compared with Group B. Though GOT and GPT were elevated slightly in one case of Group A, no severe adverse reaction was seen in both groups. These results demonstrate the possibility that an early injection of immunoglobulin preparations is effective for the treatment of granulocytopenic infections in patients with hematological malignancies.

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The in vitro antimicrobial activity of DU-6859a developed in Japan agaisnt a total of 201 isolates of respiratory pathogens including Mycobacteriaceae was determined. The minimum inhibitory concentrations (MIC's) of DU-6859a, ofloxacin, sparfloxacin, ciprofloxacin and rifampicin for 20 strains each of methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), Escherichia coli, Enterobacter cloacae, Serratia marcescens and Pseudomonas aeruginosa, 7 strains of Haemophilus influenzae, 19 strains each of Klebsiella pneumoniae and Mycobacterium avium, 21 strains of RFP-susceptible Mycobacterium tuberculosis and 15 strains of RFP-resistant M. tuberculosis were determined by the micro-broth dilution method using the Dynatech MIC 2000 system. The MIC₉₀'s of DU-6859a for the above species were ≤0.06, 1≤0.06, 0.12, 0.25, 0.5, ≤0.06, 0.12, 8, 0.25 and 4 Atg/ml respectively. DU-6859a was 2 to 16 times as active as the other agents against the species other than H. influenzae, E. coli, K. pneumoniae and E. cloacae. DU-6859a was as active as ofloxacin and ciprofloxacin against the latter four species. DU-6859a was as active as RFP and 4 to 8 times as active as ofloxacin and ciprofloxacin against RFP-susceptible M. tuberculosis. DU-6859a was 4 to 64 times as active as other agents against M. avium and RFP-resistant M. tuberculosis. We conclude from the above results that DU-6859a is one of the most useful quinolone agents for oral use as a drug of first choice in the treatment of respiratory infections.

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