[Evaluation of latamoxef in neonates]

Basic and clinical studies were carried out on latamoxef (LMOX) in relation to the use of this antibiotic in the treatment of infections in newborn infants. The results were as follows. The MICs of LMOX were determined for various clinical isolates of Gram-negative bacteria: 22 strains of E. coli, 18 strains of K. pneumoniae, 4 strains of K. oxytoca, 19 strains of P. mirabilis, 4 strains of P. vulgaris, 5 strains of P. morganii and 3 strains of C. freundii and 60 strains of H. influenzae. The MIC distributions against all of these strains for each species were 0.1, 0.2, 0.1, 0.2, 0.1, 0.1, 6.25 and 0.78 microgram/ml or less, respectively. The antibacterial activity of LMOX against all of these Gram-negative isolates was thus found to be excellent. For 38 strains of P. aeruginosa, the MIC distribution was from 6.25 to 200 micrograms/ml; accordingly, although this antibiotic does show antibacterial activity against this microbe, it is not very potent. As Gram-positive bacteria, 28 clinical isolates of S. pyogenes and 34 strains of S. aureus were tested; their respective MIC distributions were 0.39--1.56 micrograms/ml and 3.13--25 micrograms/ml. Therefore, it is clear that the antibacterial activity of LMOX against these Gram-positive bacteria is not as good as against the above-mentioned Gram-negative species. LMOX was injected intravenously as a one-shot dose of 20 mg/kg to 5 newborn infants (ranging in age from 0 to 13 days) and to 2 suckling infants (49 and 60 days of age), and then the concentration of the drug in the serum was monitored with time. The mean serum concentrations in the newborn group at various times were as follows: 38.5 micrograms/ml at 0.5 hour, 31.6 micrograms/ml at 1 hour, 26.9 micrograms/m l at 2 hours, 17.8 micrograms at 4 hours and 15.5 micrograms/ml at 6 hours. For the 2 suckling infants, the mean values at those same time points were 30.5, 23.9, 16.3, 7.4 and 4.0 micrograms/ml. In addition the value for the mean serum half-life was 4.46 hours in the newborn infant group and 1.96 hours in the suckling infant group. The urinary recovery rate was 32.3% in the newborn infant group and 49.7% in the suckling infant group during 6 hours or 8 hours.(ABSTRACT TRUNCATED AT 400 WORDS)