An outbreak due to multiresistant Acinetobacter baumannii in a burn unit: risk factors for acquisition and management

Abstract

Objectives: To describe the investigation and management of an outbreak due to multiresistant Acinetobacter baumannii and to determine risk factors for acquisition of the organism.

Setting: A 14-bed regional burn unit in a Canadian tertiary-care teaching hospital.

Design: Case-control study with multivariate analysis of potential risk factors using logistic regression analysis. Surveillance cultures were obtained from the hospital environment, from noninfected patients, and from healthcare providers.

Results: A total of 31 (13%) of 247 patients with acute burn injuries acquired multiresistant A. baumannii between December 1998 and March 2000; 18 (58%) of the patients were infected. The organism was recovered from the hospital environment and the hands of healthcare providers. Significant risk factors for acquisition of multiresistant A. baumannii were receipt of blood products (odds ratio [OR], 10.8; 95% confidence interval [CI95], 3.4 to 34.4; P < .001); procedures performed in the hydrotherapy room (OR, 4.1; CI95, 1.3 to 13.1; P = .02); and increased duration of mechanical ventilation (OR, 1.1 per day; CI95, 1.0 to 1.1; P= .02).

Interventions: Improved compliance with hand hygiene, strict patient isolation, meticulous environmental cleaning, and temporary closure of the unit to new admissions.

Conclusions: Acquisition of multiresistant A. baumannii was likely multifactorial, related to environmental contamination and contact with transiently colonized healthcare providers. Control measures addressing these potential sources of multiresistant A. baumannii were successful in terminating the outbreak. Ongoing surveillance and continued attention to hand hygiene and adequate environmental cleaning are essential to prevent recurrent outbreaks due to antibiotic-resistant bacteria in burn units.