Abstract

In a retrospective study covering the years 1975-1986, 341 episodes of invasive infections in 338 newborn infants were evaluated. Of the 365 pathogens isolated from blood and/or cerebrospinal fluid, 91% were sensitive to either ampicillin or aminoglycosides or both. Ampicillin resistance was mainly found in very low and low birthweight infants with late-onset infections, in which aerobic Gram-negative rods were common pathogens. In contrast, aminoglycoside resistance was common in early-onset infections, due to the dominance of group B streptococcal infections. The ampicillin-aminoglycoside combination had been given as initial treatment in 189 cases of septicaemia or meningitis. Treatment failed in 36 infections (20%), although all organisms were sensitive to one or both antibiotics. Treatment failed in 6 of 34 patients with meningitis but the failure was not related to ampicillin or aminoglycoside resistance. In conclusion, both in vitro and clinical results show that the ampicillin-aminoglycoside combination can be used as initial treatment of invasive infections in neonates.