Objective: To assess the role of the computerized tomography (CT) scanner in cross-transmission of carbapenem-resistant Acinetobacter baumannii between hospitalized patients undergoing CT scan.
Methods: A single-centre retrospective observational analysis of inpatients undergoing CT scans. Patient-unique CT scans were defined as 'index cases' (patients undergoing CT scan with carbapenem-resistant Acinetobacter baumannii (CRAB) colonization documented during the previous 60 days), 'incident cases' (patients found colonized with CRAB within 14 days following CT scan), and 'negative cases' (negative for CRAB before and after CT scan). CRAB acquisition was analysed by time interval between CT scan and CT scan of the prior index-case patient.
Results: Amongst 73 047 CT scans performed over 5 years, 4834 scans were performed within 12 hours of an index case. CRAB acquisition was detected in 20 patients (incident cases), including 16/2725 (5.8/1000 scans) who underwent CT scan within 6 hours of an index-case CT scan and 4/2109 (1.9/1000 scans) who had their CT scan 7-12 hours after the CT scan of an index-case patient (p 0.033, risk ratio 3.1, 95%CI 1.03-9.25). Patient characteristics for the two time periods were similar. While not the only significant predictor of CRAB acquisition (others included age and length of hospital stay prior to the CT scan), the time elapsed from an index case remained a significant predictor for CRAB acquisition on multivariate analysis (OR 0.84, 95%CI 0.74-0.95, p 0.007).
Conclusions: Performing a CT scan within 6 hours of a CT scan performed in a CRAB-positive patient was an independent predictor of CRAB acquisition, approximately tripling the risk. This probably reflects poor infection control practice in the CT suite.
Keywords: Acinetobacter baumannii; Computerized tomography; Cross-transmission; Multidrug resistance; Nosocomial infection.
Copyright © 2021 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.