An outbreak of multidrug-resistant Acinetobacter baumannii associated with pulsatile lavage wound treatment

Context: Pulsatile lavage is a high-pressure irrigation treatment used increasingly in a variety of health care settings to debride wounds. Infection control precautions are not routinely used during the procedure and are not included in pulsatile lavage equipment package labeling. Objectives: To investigate an outbreak of multidrug- resistant Acinetobacter baumannii and to test the hypothesis that pulsatile lavage wound treatment was the mode of transmission for the organism. Design: Outbreak case-control investigation including case identification, review of medical records, environmental cultures, and pulsed-field gel electrophoresis. Setting: A 1000-bed tertiary care hospital in Baltimore, Md, during September and October 2003. Patients: The investigation included 11 patients infected or colonized with multidrug-resistant A baumannii. Seven of these patients met the case definition for the case-control study and were compared with 28 controls randomly selected from a list of inpatients without multidrug-resistant A baumannii who had a wound care consultation. Main Outcome Measure: Infection or colonization with multidrug-resistant A baumannii. Results: Eleven patients had cultures that grew multidrug-resistant A baumannii during the outbreak period. Of the 10 health care-associated cases, 8 had received pulsatile lavage treatment. One strain of multidrug-resistant A baumannii was recovered from all 6 pulsatile lavage patients who had isolates available for pulsed-field gel electrophoresis analysis and from multiple surfaces in the wound care area. Six of 7 cases (86%) were treated with pulsatile lavage vs 4 of 28 controls (14%) (odds ratio, 36; 95% confidence interval, 2.8-1721; P<.001). These results confirm that pulsatile lavage was a significant risk factor for acquisition of multidrug-resistant A baumannii. Conclusions: Transmission was apparently caused by dissemination of multidrug-resistant A baumannii during the pulsatile lavage procedure, resulting in environmental contamination. Appropriate infection control precautions should be used during pulsatile lavage therapy and should be included in pulsatile lavage equipment labeling.