The role of the computerized tomography scanner in the cross-transmission of carbapenem-resistant Acinetobacter baumannii between hospitalized patients.

Abstract

BACKGROUND\nCarbapenem-resistant Acinetobacter baumannii (CRAB) can cause life-threatening infections and nosocomial outbreaks. It can be transmitted via multiple fomites. The role of the computerized tomography (CT) scanner in cross-transmission has not been described.\n\n\nMETHODS\nA single-center retrospective observational analysis of in-patients undergoing CT-scans. Patient unique CT-scans were defined as: Index-Cases (patients undergoing CT-scan with CRAB colonization documented during the previous 60\xa0days), Incident-Cases (patients found colonized with CRAB within 14\xa0days following CT-scan), and Negative-Cases (negative for CRAB before and after CT-scan). CRAB acquisition was analyzed by time interval between CT-scan and CT-scan of the prior Index-Case patient.\n\n\nRESULTS\nAmongst 73,047 CT-scans performed over five years, 4,834 scans were performed within 12\xa0hours of an Index-Case. CRAB acquisition was detected in 20 patients (Incident-Cases) including 16/2,725 (5.8/1,000 scans) who underwent CT-scan within 6\xa0hours of an Index-case CT-scan and 4/2,109 (1.9/1,000 scans) who had their CT-scan from 7-12\xa0hours after the CT-scan of an Index-case patient (p=0.033, risk-ratio of 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).\n\n\nCONCLUSIONS\nPerforming a CT-scan within 6\xa0hours 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.