Necrotizing enterocolitis (NEC) is an acute abdominal emergency of unknown etiology predominantly affecting preterm infants. We describe a cluster of NEC in a level III NICU involving 15 infants over a 6-month period. Cohorting and stringent infection control measures were associated with termination of the cluster. A case-control study was used to investigate potential risk factors associated with development of NEC.
Stool samples were collected from 55 infants (10 of 15 NEC and 45 non-NEC controls). Enteric pathogens were identified by culture and/or molecular diagnostic techniques. For the case-control study, controls were selected from admitted neonates during the same time and in the preceding 6-month period, matched for gestation and birthweight.
Forty percent (4/10) of NEC infants had norovirus RNA detected compared with 9% (4/45) of non-NEC infants (OR: 6.83, 95% CI: 1.3–34.9, P = 0.021). A lower rate of prolonged rupture of membranes and a higher rate of maternal smoking was also observed in NEC infants than in controls. No significant differences in incidences of chorioamnionitis, intrapartum antibiotics, volume of feedings, time of first formula feeding, and rates of patent ductus arteriosus or intrauterine growth retardation were detected.
Infants who developed NEC had an increased incidence of norovirus detection in their stool following diagnosis. This further strengthens the case for an etiologic role of norovirus in the pathogenesis of NEC.
From the *Department of Infectious Diseases, †Department of Infection Control and Epidemiology, ‡Monash Newborn, Monash Children's Hospital, Southern Health, Victoria, Australia; §Enteric Virus group, Murdoch Children's Research Institute, Royal Children's Hospital, Victoria, Australia; ¶Department of Microbiology, La Trobe University, Victoria, Australia; ∥Department of Epidemiology and Preventative Medicine, School of Public Health and Preventative Medicine, Monash University, Victoria, Australia; **Biostatistics, Monash Institute of Health Services Research, Monash University, Victoria, Australia; ††Department of Paediatrics, Monash University and Paediatric Infectious Diseases Unit, Monash Medical Centre, Southern Health, Victoria, Australia; ‡‡Department of Infectious Diseases, Monash Medical Centre, Southern Health, Victoria, Australia; and §§Immunisation CCRE Murdoch Children's Research Institute, Monash Children's Hospital, Southern Health, Victoria, Australia.
Accepted for publication January 26, 2010.
R.S. and K.T. both are the first authors for this manuscript.
Address for correspondence: Rhonda Stuart, Department of Infectious Diseases, Monash Medical Centre, Clayton. Victoria 3168, Australia. E-mail: firstname.lastname@example.org.