Environmental contamination of carbapenem-resistant gram-negative bacteria away from isolated patients in intensive care unit: a comprehensive surveillance study

Environmental contamination by carbapenem-resistant gram-negative bacteria (CR-GNB) contributes to healthcare-associated infections in intensive care unit (ICU). However, contamination in areas away from isolated patients remains inadequately characterized, and local epidemiological data are limited. A comprehensive surveillance study was conducted in the ICU of a tertiary hospital from January 2019 to December 2022. Monthly collections included clinical specimens (sputum, urine, blood) and environmental samples (inanimate surfaces, healthcare workers' hands). Gram-negative bacteria were cultured, and carbapenem sensitivity testing was performed. Among 5,097 clinical specimens collected over the 4-year study period, 898 (17.6%) GNB isolates and 405 (8.0%) CR-GNB isolates were detected, with Klebsiella pneumoniae and carbapenem-resistant Acinetobacter baumannii (CRAB) being the most common species. From 2,215 environmental samples, 144 (6.5%) GNB and 90 (4.1%) CR-GNB strains were identified, predominantly A. baumannii and CRAB. The overall CR-GNB environmental contamination rates were highest on work coats (6.8%), followed by nonisolated patient medical devices (5.8%), nonisolated patient bed units (4.3%), mobile phones (4.1%), doctors' offices and nurses' stations (3.6%), and healthcare workers' hands (2.0%). Spearman's correlation analysis revealed a significant positive correlation between the monthly number of positive A. baumannii or CRAB isolates from environmental samples and clinical specimens. CR-GNB, particularly CRAB, contaminates ICU environments, including nonisolated patient areas and healthcare stations, highlighting the need for enhanced environmental surveillance in the ICU.