Selecting antibiotics for nosocomial bacterial infections in patients requiring neonatal intensive care.

Nosocomial infections increase neonates' morbidity, hospital costs, and mortality. These infections occur most commonly in very low birth weight infants, who frequently required plastic intravascular catheters and parenteral nutrition. Diagnosis often relies on a combination of laboratory tests and nonspecific clinical signs. Criteria for diagnosing nosocomial infections have been published by the Centers for Disease Control (CDC) and should be used to standardize the identification of cases. Initial antibiotic therapy depends on (1) the bacterial species most likely to cause infection, (2) antibiotic resistance patterns in one's own hospital, (3) the patient's clinical condition, and (4) previous antibiotic therapy. Antibiotic coverage of both gram-positive and gram-negative bacteria is necessary. Following laboratory identification of the infecting organism and the antibiotic susceptibility results, the patient should be reevaluated and definitive therapy prescribed. Multiple antibiotics may be needed as definitive therapy if (1) the infecting organism is likely to develop resistant mutants during therapy (e.g., Pseudomonas species), (2) higher bactericidal serum activity is required than can usually be achieved with a single agent (e.g., enterococci, Listeria), (3) the patient is neutropenic or otherwise severely immunocompromised, or (4) blood cultures are persistently positive for bacteria despite appropriate therapy with a single agent. Attempts to prevent nosocomial bacteremias by routinely administering prophylactic vancomycin may hasten the development of vancomycin-resistant, coagulase-negative staphylococci or enterococci and should be avoided.