Seven point mutations were detected in 10 quinolone-resistant gyrA mutants of Escherichia coli KL 16, i. e., Ser-83 to Leu (4 strains), Ser-83 to Trp, Asp-87 to Asn, Gly-81 to Cys, Ala-84 to Pro, Ala-67 to Ser and Gln-106 to His. Among 13 quinolone-resistant gyrB mutants of E. coli KL 16, 2 point mutations were detected, Asp-426 to Asn (9 strains) and Lys-447 to Glu (4 strains). The former mutation (type 1) confers resistance to all the quinolones tested, while the latter mutation (type 2) results in resistance to acidic quinolones and hypersusceptibility to amphoteric quinolones. Almost all the gyrA and gyrB mutations are believed to occur on protein surfaces, based on cpmputer analysis. Mutant DNA gyrases reconstituted from wild-type GyrA (or GyrB) and mutant GyrB (or GyrA) proteins were resistant to or hypersensitive to quinolones as expected from the MICs for the corresponding mutants. ³H-enoxacin was bound to gyrase-DNA complexes but not to gyrase alone or to DNA alone. The amount of enoxacin bound to the GyrA mutant gyrase-DNA complex was the same as that bound to the wild-type gyrase-DNA complex, but the binding affinity to the former was one-tenth of the binding to the latter. The amount of enoxacin bound to the type 1 GyrB mutant gyrase-DNA complex was one-seventh that bound to the wild-type complex. Enoxacin was bound to the type 2 GyrB mutant gyrase-DNA complex in the same amount as to the wild-type complex with five-times greater affinity for the former than the latter. These data suggest that quinoloneresistance of DNA gyrase can be explained by the decreased amount of quinolone binding or decreased quinolone binding affinity to gyrase-DNA complexes.

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We investigated 983 strains of Staphylococcus aureus isolated from patients in Osaka Medical College Hospital between January 1976 and March 1991 to examine changes in the susceptibility of S. aureus to various antibiotics and nosocomial infections caused by methicillin-resistant S. aureus (MRSA). The incidence of penicillinase-resistant penicillin-resistant strains of S. aureus increased every year. For 1990 and 1991, MIC80 were 100μg/ml for methicillin and oxacillin, and 50 and 25 μg/ml for cloxacillin and dicloxacillin, respectively. The frequency of isolation of MRSA was 1.2% for the period of 1976 to 1980, and 43.9% for 1990 and 1991, indicating that the strains resistant to many antibiotics including β-lactams were increasing very rapidly. The MIC80 of amikacin, minocycline and vancomycinonly for these strains were 12.5μg/ml or less. The strains resistant to minocycline tended to increase. Of the coagulase types of MRSA, Type IV strains were 50.7% and Type II strains were 16.4% for the period of 1976 to 1988, but Type II strains increased to 46.3% and Type IV strains were 23.9% for the period of 1989 to 1991.

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The effect of the antibiotics latamoxef (LMOX) and aztreonam (AZT) (final concentrations: 500, 1, 000 and 3, 000μg/ml) and C-reactive protein (CRP), one of the acute proteins in infection and inflammation (final concentrations: 0.5 and 5.0mg/dl) on cultured human vascular endothelial cells was investigated measuring the production of prostacyclin (PGI₂) and concentration of cyclic AMP (cAMP) in endothelial cells, and the concentration of intracellular free Ca²⁺ ([Ca²⁺] i). Endothelial cells were isolated from the human umbilical vein and cultured to obtain confluent cells. Production of PGI₂ was assessed by measuring its stable metabolite 6-keto-PGF1a in the culture supernatant by a radioimmunoassay (RIA) techniqus. Although there was no significant difference in this parameter in the presence of LMOX or AZT compared with the control, production significantly increased in the presence of CRP (5.0 mg/dl). cAMP concentration in the culture supernatant was measured by an RIA technique; LMOX, AZT and CRP had no affect on cAMP concentration. [Ca²⁺] i was measured fluorometrically by adding the Ca²⁺-sensitive fluorescein fura 2/AM to a suspension of endothelial cells and stimulating them with histamine. When compared with the control, there was no significant difference in [Cel] i in the presence of either LMOX or AZT. On the other hand, there was a significant increase in [Ca²⁺] i in the presence of CRP (5.0 mg/dl), both before and after histamine stimulation. When Ca²⁺ was eliminated from the suspension of endothelial cells, there was no significant difference in [Ca²⁺] i in the presence of CRP (5.0 mg/dl) before or after histamine stimulation, when compared with the control. [Ca²⁺] i increased in the presence of extracellular Ca²⁺ in response to direct stimulation with CRP (5.0mg/dl) instead of histamine. However, it did not increase in a Ca²⁺-free solution. This suggested that extracellular Ca²⁺ is essential for CRP to increase [Ca²⁺] i in endothelial cells. Based on these results, in appears that LMOX or AZT have no effect on the production of PGI₂in vascular endothelial cells, but that CRP enhanced PGI₂ production through the increase in an influx of Ca²⁺ into endothelial cells without reducing the concentration of cAMP, liberating Ca²⁺ from its intracellular storage site, therebyincreasing [Ca²⁺] i

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The purpose of this study was the objective evaluation of the influence of lysozyme chloride on antibiotics. Cefuzonam (CZON), which is a third generation cephalosporin antibiotic, penetrates less into sputum than most other cephem antibiotics. CZON 1 g was administered by intravenous drip infusion over 1 h twice a day for 5 days with or without oral lysozyme chloride 270 mg per day in 3 divided doses in patients with chronic lower respiratory tract infections. To reduce inter-and intrapatient variability, we performed a crossover comparative pharmacokinetic study. Blood and sputum samples were collected at timed intervals, stored at-40°C and CZON concentrations were assayed by a bioassay method using Escherichia coli NIHJ. The serum and sputum concentrations of CZON in 7 patients with chronic respiratory tract infections were measured. The geometrical mean CZON concentration in sputum was 0.055 μg/ml in patients given CZON 1.0 g intravenous drip infusions over 1 h twice a day without oral lysozyme chloride. Comparative study revealed geometrical mean sputum CZON levels as high as 0.102 μg/ml (P<0.01) in patients given CZON combined with per oral lysozyme chloride 270 mg per day in 3 divided doses. These findings show that lysozyme chloride increases cephem antibiotic concentration in sputum in patients with chronic respiratory tract infections.

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We investigated the effects of an antacid (dried aluminum hydroxide gel, AL) and probenecid on the gastrointestinal absorption and renal excretion of Y-26611 after oral administration in six healthy male volunteers. The subjects were given 200mg of Y-26611 p. o. with or without 1.0 g of AL or 1.5 g of probenecid. The time course of plasma and saliva levels, urinary concentrations and urinary recovery of Y-26611, and its pharmacokinetic parameters were then determined. Y-26611 concentrations in the samples were measured by the HPLC method. The pharmacokinetic parameters obtained for Y-26611 were as follows: C_max, T_max, T_1/2 and AUC_0-∞ after Y-26611 alone were 1.090 μg/ml, 1.1 h, 5.1 h and 3.821 μg·h/ml, respectively, after combined administration with AL, 0.082 μg/ml, 1.8 h, 5.9 h and 0.629 μg·h/ml, respectively, and after combined administration with probenecid, 1.090 μg/ml, 1.7 h, 4.4 h and 7.033 μg·h/ml, respectively. The levels of Y-26611 in saliva were less than 10% of those in plasma regardless of method of administration. The urinary excretion rates of Y-26611 over 24 h were 40.8%, 5.3% and 22.5% for Y-26611 administered alone, with AL, and with probenecid, respectively. Gastrointestional absorption of Y-26611 was markedly inhibited by interaction with AL. Furthermore, the effects of probenecid on the pharmacokinetic parameters of Y-26611 suggest that the urinary excretion of Y-26611 is related to secretion by the renal tubules.

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We studied the effect of antiulcer drugs such as aluminum hydroxide gel, troxipide and famotidine on the gastrointestinal absorption of norfloxacin in six healthy adult volunteers. Two hundred milligrams of norfloxacin was given orally to each subject in a fasting state with or withont the antiulcer drugs. The peak serum concentration (C_max), area under the serum concentration-time curve (AUC) and urinary recovery rate of norfloxacin were significantly decreased by the concurrent administration of aluminum hydroxide gel. The concomitant use of troxipide did not affect the absorption of norfloxacin. The C_max of norfloxacin was significantly decreased by pre-medication famotidine 8 hours before the administration of norfloxacin but no significant changes were found in the AUC or the urinary recovery rate. In conclusion, we should administer antiulcer drugs carefully when used in combination therapy with norfloxacin.

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We measured the concentration of cefuzonam (CZON) in 6 patients with odontogenic maxillary sinusitis and 28 patients with postoperative maxillary cysts and obtained the following results.
1) The mean concentration of CZON in maxillary sinus mucous membrane 1 h after intravenous injection was 8.4±3.2μg/g, the concentration in the maxillary cyst walls was 12.0±8.1μg/g 1 h after injection, and the serum concentration 30 min and 1 h after intravenous injection was 30.2±11.0μg/ml and 14.3±9.0μg/ml, respectively. The concentration of CZON in the bloods was higher than in the tissues. Pharmacokinetic studies yielded a T (1/2) of 30 min, a C_max of 54.2μg/ml and an AUC of 40.2μg·h/ml.
2) Streptococcus and Peptostreptococcus were most often isolated in odontogenic maxillary sinusitis (12 straints) and from cyst walls (26 straints). The MICs of CZON against Streptococcus and Peptostreptococcus were 0.05-0.2μg/ml and 0.025-0.5μg/ml, respectively.
3) The proportions of aerobes to anaerobes were 63% (26 straints) to 37% (16 strains)
4) The pattern of bacterial distribution did not differ among odontogenic maxillary sinusitis and postoperative maxillary cyst.

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The efficacy of an antifungal drug, fluconazole, on severe infections associated with hematologic disorders was evaluated. Fluconazole was given intravenously to treat 45 fungal infections occurring in 33 patients with hematologic diseases. The underlying diseases were acute myelogenous leukemia in 9 cases, non-Hodgkin's lymphoma in 8 cases, acute lymphoblastic leukemia in 4 cases, myelodysplastic syndrome in 3 cases, chronic myelogenous leukemia in 3 cases, aplastic anemia in 2 cases, chronic lymphocytic leukemia in 2 cases, and one case of multiple myeloma. The complicating infections included 6 cases of proven mycosis and 39 cases of suspected mycosis. Candida was isolated from 4 cases (Candida albicans, 3; Candida parapsilosis, 1) and Aspergillus from 2 cases (Aspergillus fumigatus, 1; Aspergillus niger, 1). Suspected mycosis consisted of 7 cases of pneumonia and 32 cases suspected fungemia. The results were as follows.
1) Good clinical outcome was observed in all 4 Candida infections, whereas efficacy was poor and fair, respectively, in 2 Aspergillus infections.
2) Clinical responses in suspected mycosis were 57.1% and 62.5% in pneumonia and suspected fungemia, respectively.
3) Side-effects were observed in 2 cases, and consisted of transient laboratory liver function test abnormality and skin eruption.
Hence, fluconazole is considered to be a potent, safe antifungal agent for the treatment of proven and suspected fungal infection associated with hematologic disorders.

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An attempt was made to determine the break point of 32 antimicrobial agents administered in Japan to 1, 372 patients with respiratory tract infections which the causative pathogens, clinical effects and bacteriological effects were documented. The break point could be easily determined in chronic respiratory infections i. e. chronic bronchitis and bronchiectasis compared with acute respiratory infections i. e. acute bronchitis and acute pneumonia. The break point of β-lactams could be determined easily because the transitional zone from the susceptible to the resistant break point was limited in a narrow range. On the other hand, the break point of new-quinolones could be found only with difficulty because the transitional zone was wide. Sputum concentrations of antimicrobial agents seemed to be one of the major factors which determine the break point against respiratory infections. Although, the results obtained in this study were similar to those of NCCLS in the USA, further study is necessary to determine the precise break point against respiratory infections in Japan, because sufficient data are not yet available.

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A study was conducted on the various factors influencing the clinical effects of 10 oral antibiotics. We analyzed the results of clinical tests involving 194 cases of bacterial pneumonia during the past 10 years. The following data, compiled prior to the initiation of treatment, were considered to have an important influence on clinical effect: age, body weight, underlying disease, sputum characteristics, moist rale, pneumonic score, erythrocyte sedimentation rate, CRP and causative organism. Six factors proved useful for immediate evaluation during the clinical examination: age, body weight, underlying disease, sputum characteristics, moist rale and pneumonic score. The seriousness of the pneumonia was then calculated using the observations obtained from these factors. The results of drug administration revealed that the therapeutic effect was insignificant in those patients whose seriousness of pneumonia was rated at eight points or more. Oral antibiotics therefore have no efficacy once seriousness has reached the eight-point level. The percentage of presumed clinical therapeutic effects to actual prognosis was 88% correct, suggesting that this system is useful for indicating a standard for prescribing oral antibiotics.

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