This case-control study of full-term newborns with presumed or proven bacterial infection compared the efficacy, safety and tolerability of switch antibiotic therapy and traditional completely intravenous antibiotic administration. there were 36 newborns treated with switch therapy (i.v. ampicillin + sulbactam combined with i.v. amikacin for 3 days followed by oral cefpodoxime proxetil for 5 days); there were 72 full-term newborns with the same characteristics as controls who received i.v. ampicillin + sulbactam combined with i.v. amikacin for 3 days followed by i.v. ampicillin + sulbactam alone for a further 5 days. the results showed that full-term newborns with presumed or proven bacterial infection initially treated with intravenous antibiotics can be switched to oral antibiotics after 3 days' therapy if physical and laboratory data indicate the disappearance of infection, thus significantly reducing the length of stay in the neonatal intensive care unit and significantly increasing breastfeeding, without having any negative clinical impact.