[Two cases of neonatal meningitis after new gentamicin dosing guidelines].

Neonates with suspected or proven sepsis are treated with ampicillin and until recently with 5 mg gentamicin/kg every 24 h. New guidelines recommend the same gentamicin dose, but with longer intervals depending on gestational age. Two neonates receiving gentamicin every 48 h improved initially, but both deteriorated again before the second dose. In both infants ampicillin-resistant but gentamicin-sensitive Escherichia coli was found. In one of the infants a resistant/less sensitive E. coli strain was also found in the cerebrospinal fluid. The rationale for the new dosing guidelines is discussed.