Uncommon pathogens in newborn infants.

Newborns, especially premature newborns, are immunocompromised and have increased susceptibility to infections by opportunistic organisms. Experience with these uncommon pathogens is limited to a handful of case reports and to several reports of neonatal intensive care nursery outbreaks. Many of these infections are misdiagnosed or diagnosed at autopsy because of the nonspecific features of their clinical presentation, difficulties in recovering the pathogen from body fluids, or because the microorganism is considered either a contaminant or nonpathogenic. This review summarizes the clinical characteristics of these uncommon pathogens and emphasizes the existence of dual and polymicrobial infections. The limited experience with many of these infections precludes the formulation of an optimal therapeutic approach.