Epidemiology and diagnosis of hospital-acquired conjunctivitis among neonatal intensive care unit patients

Background: Few recent reports describe the epidemiology and risk factors for health care-associated conjunctivitis among neonatal intensive care unit (NICU) patients in developed countries. Reporting may be inaccurate in this population given that the National Nosocomial Infection Surveillance System (NNIS) definition is largely dependent on a positive culture, whereas clinical practice often consists of empiric treatment. Objectives: We describe the epidemiology of conjunctivitis among neonates in 2 level III-IV NICUs and compare the NNIS definition with our study definition: eye drainage and empiric treatment with or without a culture. Methods: Patient demographics, clinical, device usage and conjunctivitis data collected prospectively from March 2001 through January 2003 were analyzed. Results: Conjunctivitis occurred in 5% (n = 154/2935) of infants, off whom 51% (n = 79) were in NICU 1 and 49% (n = 75) in NICU 2. Predominant pathogens included coagulase-negative staphylococcii (25%), Staphylococcus aureus (19%) and Klebsiella spp. (10%). Significant predictors of conjunctivitis included low birth weight, use of ventilator or nasal cannula continuous positive airway pressure and study year. Oplithalmologic examination was an additional predictor of infection in NICU 1. Eye examination data were unavailable for NICU 2. Only 62% of cases that met the study definition for conjunctivitis met the NNIS definition, because many infants received empiric treatment. Conclusions: Clinical conjunctivitis was associated with low birth weight and patient care factors that could lead to contamination of the eye with respiratory tract secretions. The NNIS definition failed to detect 38% of clinical infections. Consideration should be given to revising the definition of conjunctivitis for the NICU population.