Purpose: Outbreaks of adenovirus in neonatal intensive care units (NICUs) can lead to widespread transmission and serious adverse outcomes. We describe the investigation, response, and successful containment of an adenovirus outbreak in a NICU associated with contaminated handheld ophthalmologic equipment used during retinopathy of prematurity (ROP) screening.

Design: Epidemiologic outbreak investigation.

Participants: A total of 23 hospitalized neonates, as well as NICU staff and parents of affected infants.

Main outcome measures: Routine surveillance identified an adenovirus outbreak in a level IV NICU in August 2016. Epidemiologic investigation followed, including chart review, staff interviews, and observations. Cases were defined as hospital-acquired adenovirus identified from any clinical specimen (NICU patient or employee) or compatible illness in a family member. Real-time polymerase chain reaction (PCR) and partial- and whole-genome sequencing assays were used for testing of clinical and environmental specimens.

Results: We identified 23 primary neonatal cases and 9 secondary cases (6 employees and 3 parents). All neonatal case-patients had respiratory symptoms. Of these, 5 developed pneumonia and 12 required increased respiratory support. Less than half (48%) had ocular symptoms. All neonatal case-patients (100%) had undergone a recent ophthalmologic examination, and 54% of neonates undergoing examinations developed adenovirus infection. All affected employees and parents had direct contact with infected neonates. Observations revealed inconsistent disinfection of bedside ophthalmologic equipment and limited glove use. Sampling of 2 handheld lenses and 2 indirect ophthalmoscopes revealed adenovirus serotype 3 DNA on each device. Sequence analysis of 16 neonatal cases, 2 employees, and 2 lenses showed that cases and equipment shared 100% identity across the entire adenovirus genome. Infection control interventions included strict hand hygiene, including glove use; isolation precautions; enhanced cleaning of lenses and ophthalmoscopes between all examinations; and staff furlough. We identified no cases of secondary transmission among neonates.

Conclusions: Adenovirus outbreaks can result from use of contaminated ophthalmologic equipment. Even equipment that does not directly contact patients can facilitate indirect transmission. Patient-to-patient transmission can be prevented with strict infection control measures and equipment cleaning. Ophthalmologists performing inpatient examinations should take measures to avoid adenoviral spread from contaminated handheld equipment.