Piperacillin in the newborn infant. A clinical and pharmacologic study

: The study involved 70 neonates born at 27 to 48 weeks of pregnancy (mean: 34.2 weeks) and weighing between 840 and 4350 g (mean: 1860 g). In every case piperacillin was combined with an aminoglycoside. The infants were treated for materno-foetal infection (14), post-partum infection (19), enterocolitis (18, surgical in 9 cases) and other post-operative infections (19). The antibiotic combination was given prophylactically in 2 cases. Fifty micro-organisms were isolated in 39 patients: 24 from blood (hemoculture), 2 from CSF, 24 from multiple peripheral samples. There were 13 Gram-positive organisms (Streptococcus B, D, A, Listeria spp.) and 37 Gram-negative organisms (E. coli 14, Klebsiella spp. 10, Enterobacter spp. 6). Clinical and bacteriological cure was obtained in 67 patients. Three failures were recorded, with resistance to treatment of Klebsiella pneumoniae and emergence (at hemoculture) of Klebsiella oxytoca under treatment in one patient and of Enterobacter cloacae in another patient. A pharmacokinetic study was performed in 47 neonates. Piperacillin (75 mg/kg per dose) was given twice a day until the 8th day post-partum and three times a day subsequently. The antibiotic was administered either by 30-min infusions or by intravenous or intramuscular injections; 124 serum level measurements were carried out at peak and/or residual level. In 44 infants with normal renal and hepatic function the mean residual level was 23 micrograms/ml (range: 7-100 micrograms/ml) and the mean peak level was 119 micrograms/ml (range: 47-278 micrograms/ml). No local or systemic side-effect was noted, and there was no evidence of toxicity.