Increased risk of illness among nursery staff caring for neonates with necrotizing enterocolitis.

In 1983 an outbreak of necrotizing enterocolitis (NEC) and hemorrhagic gastroenteritis occurred in our newborn nurseries. Eleven children were ill and three required bowel resections. During the outbreak many of the medical and nursing staff in the nurseries also were ill, prompting a microbiologic and epidemiologic investigation. Bacterial and viral cultures, Clostridium difficile toxin assays, enzyme-linked immunosorbent assays for viral antigens and immunoelectron microscopy of stools identified no associated pathogen. However, using a method of calculating relative risk as an incidence density ratio, we found that nurses who had cared for ill infants were at higher risk for sick call within the 9 days following exposure than nurses who had cared for babies without NEC (relative risk, 1.96; P = 0.05). These results provide additional evidence that a transmissible agent may be responsible for some cases of NEC and support the recommendation for infection control measures during outbreaks. The epidemiologic methods used in this study may be useful in prospective studies of NEC and may help to provide further clues to the cause of this disease.