We describe the first outbreak of multiple drug-resistant Acinetobacter baumannii (MDR-Ab) in a neonatal intensive care unit in the United States.
MDR-Ab was identified in the blood of a 24-week gestation, 7-day-old extremely low birth weight neonate. Multiple samplings of surveillance surface cultures were performed on exposed and nonexposed neonates. Enhanced infection control measures were implemented. Pulsed-field gel electrophoresis was performed to determine the genetic relatedness of the MDR-Ab isolates. Medical records were reviewed for all exposed patients.
MDR-Ab was recovered from 6 additional neonates. Of these 7 MDR-Ab (index + 6) neonates, 4 died, 3 of whom had positive blood cultures. All affected neonates were born between 23 to 26 weeks gestational age, and were <7days postnatal age and <750 g (430–720) at the time of exposure. All were housed within the same room as the index case. None of the other 5 exposed neonates older than postnatal day 7 or weighing >750 g at birth were affected. No additional cases occurred outside the original room. Pulsed-field gel electrophoresis was consistent with a clonal origin, identical to MDR-Ab recovered from the referring hospital.
This MDR-Ab outbreak was rapidly controlled with enhanced infection control measures and was novel in that it affected only <750 g neonates, at ≤26 weeks gestational age, and ≤7 days postnatal age at the time of exposure, suggesting that invasive Ab has a special affinity for damaged or nonkeratinized immature skin in developmentally immature immunologic hosts.
From the *Division of Neonatology, Department of Pediatrics, Winthrop University Hospital, and Assistant Professor of Clinical Pediatrics, SUNY Stony Brook School of Medicine, Mineola, NY; and †Division of Pediatric Infectious Disease, Department of Pediatrics, ‡Department of Pathology, §Division of Infection Control, Department of Medicine, and ¶Division of Newborn Medicine, Department of Pediatrics, Maria Fareri Children’s Hospital at Westchester Medical Center, NY Medical College, Valhalla, NY.
Accepted for publication September 4, 2008.
Address for correspondence: Aryeh Simmonds, MD, FAAP, Winthrop University Hospital, Division of Neonatology, 259 First Street, Mineola, NY 11501. E-mail: email@example.com.