An outbreak of carbapenem-resistant Acinetobacter baumannii infection in a neonatal intensive care unit: investigation and control

Abstract

Objective: To investigate the mode of transmission of and assess control measures for an outbreak of carbapenem-resistant (multidrug-resistant) Acinetobacter baumannii infection involving 6 premature infants.

Design: An outbreak investigation based on medical record review was performed for each neonate during the outbreak (from November 2008 through January 2009) in conjunction with an infection control investigation.

Setting: A 36-bed, level 3 neonatal intensive care unit in a university-affiliated teaching hospital in Detroit, Michigan.

Interventions: Specimens were obtained for surveillance cultures from all infants in the unit. In addition, geographic cohorting of affected infants and their nursing staff, contact isolation, re-emphasis of adherence to infection control practices, environmental cleaning, and use of educational modules were implemented to control the outbreak.

Results: Six infants (age, 10-197 days) with multidrug-resistant A. baumannii infection were identified. All 6 infants were premature (gestational age, 23-30 weeks) and had extremely low birth weights (birth weight, 1000 g or less). Conditions included conjunctivitis (2 infants), pneumonia (4 infants), and bacteremia (1 infant). One infant died of causes not attributed to infection with the organism; the remaining 5 infants were discharged home. All surveillance cultures of unaffected infants yielded negative results.

Conclusions: The spread of multidrug-resistant A. baumannii infection was suspected to be due to staff members who spread the pathogen through close contact with infants. Clinical staff recognition of the importance of multidrug-resistant A. baumannii recovery from neonatal intensive care unit patients, geographic cohorting of infected patients, enhanced infection control practices, and staff education resulted in control of the spread of the organism.