Conjunctival colonization of infants hospitalized in a neonatal intensive care unit: A longitudinal analysis

OBJECTIVES: To determine the frequency of conjunctival colonization, identify the colonizing flora, and correlate culture results with physical findings in infants in a NICU. DESIGN: Surveillance study. SETTING: Level III NICU of a large university teaching hospital. PATIENTS: All infants admitted for longer than 24 hours during a 26-week period. METHODS: Weekly bacterial conjunctival cultures were performed for all infants. The conjunctival appearance at the time of culture was recorded. The frequency, identity, and correlation of culture results with physical findings were determined. RESULTS: One thousand ninety-one cultures were performed for 319 infants: 133 (42%) had no positive cultures and 186 (58%) had at least one positive culture. Culture analysis revealed that 411 (38%) were positive and yielded 494 isolates comprising more than 18 bacterial species. Bacteria most commonly isolated included coagulase-negative Staphylococcus (CoNS) (75%), viri-dans group streptococci (8.7%), Staphylococcus aureus (3.8%), Enterococcus species (2.6%), and Serratia marcescens (2.4%). The frequency of non-CoNS isolates increased significantly during the first 6 weeks of patient hospital stay (6% [1 to 3 weeks] to 12% [4 to 6 weeks]; P =.01), with an increasing trend to 15 weeks (18%). Correlation of bacteriologic results with physical findings demonstrated that infants with non-CoNS isolates exhibited conjunctival edema, erythema, or exudates more frequently than did infants with CoNS alone (30% vs 13%; P =.0001). CONCLUSIONS: Conjunctival colonization was common among infants in a NICU. Prolonged hospitalization predisposes to colonization with potentially pathogenic organisms. Physical findings were more likely in patients with non-CoNS conjunctival isolates (Infect Control Hosp Epidemiol 2004;25:216-220).