Physiological analysis of bicozamycin high-producing Streptomyces griseoflavus used at industrial level.

: Ceftizoxime (CZX) was evaluated for absorption and excretion as well as for therapeutic effectiveness in neonates and premature infants. The following results were obtained. 1. Serum CZX concentrations were determined in 8 neonates or premature infants who were not more than 6 days old. Serum concentrations of the drug were examined in 6 neonates and/or premature infants after intravenous administration of about 20 mg/kg body weight. Average concentration at 1/2, 2, 4 and 6 hours after administration were 52.3, 36.4, 26.7 and 16.7 micrograms/ml, respectively. Serum concentrations in the other 2 infants who were given 29.7 and 25.1 mg/kg, were as high as 71 and 94 micrograms/ml at 1/2 hour and 22.1 and 39 micrograms/ml at 6 hours, respectively. Serum half-lives in 5 of the 6 mature neonates ranged from 2.36 to 3.34 hours, with averaged 2.75 hours, but was exceptionally long, 7.92 hours, in the other one. Half-lives in the 2 premature infants were 4.14 and 4.90 hours. 2. The therapeutic effectiveness on bacterial infection was evaluated for 10 newborn infants. Intravenous doses of 16.9 to 24.6 mg/kg were given in b.i.d. or t.i.d. regimen to 4 cases with pneumonia and 2 with septicemia, urinary tract infection and fetal infection each. To 1 infant with septicemia complicated with cephalohematoma, higher doses ranged from 21.8 to 49.8 mg/kg were given t.i.d. or q.i.d. Therapeutic efficacies were assessed as "Excellent" in 3, "Good" in 6, and "Poor" in 1, with an efficacy rate of 90.0%. Eradication of bacteria was complete in 2 infants each with Escherichia coli-induced septicemia or urinary tract infection. 3. For prophylactic use, the drug was given to 8 newborn infants in intravenous doses of 17.5 to 29.1 mg/kg b.i.d. or t.i.d. and no infection occurred in 7 cases. 4. No adverse reactions were obtained. Slight and transient increases in platelet count, GOT and GPT in 1 case and eosinophilia in another were observed. 5. These results suggested that CZX in an intravenous dose of 20 mg/kg b.i.d. or t.i.d. regimen in newborn infants up to 7 days of age would be effective and safe for the treatment of neonatal bacterial infections.