Büchler, et al. (2023) explain that Carbapenem-resistant Pseudomonas aeruginosa (CRPA) are a serious cause of healthcare-associated infections. They observe that, "Part of the infection prevention and control measures are outbreak investigations (OI) of patients, healthcare workers (HCWs) and the environment after identifying a CRPA to identify carriers and environmental reservoirs, so that targeted actions can be taken to prevent further transmission. However, little is known on when and how to perform such OI."

This systematic review sought to summarize OI performed after detection of CRPA in the endemic and epidemic hospital setting.

Articles  were identified through a literature research in multiple databases through Jan. 12, 2022; 126 studies were included. In both the endemic and the epidemic setting, a median number of two out of seven predefined components of OI were identified. In the endemic setting, the most frequent component of OI was screening of the environment (28 studies, 62.2%). In the epidemic setting, screening of the environment (72 studies, 88.9%), and screening of patients during hospitalization (30 studies, 37%) were most frequently performed. Only 19 out of 126 studies (15.1%) reported screening of contact patients, and 37 studies reported screening of healthcare workers (HCW, 29.4%).

The researchers conclude that "Due to probable underreporting of OI in the literature, the available evidence for the usefulness of the individual components of OI is scarce. This could lead to inhomogeneous performance of OI after detection of CRPA in the healthcare setting, and with this, potential under- or over-screening. While we could show evidence for the usefulness for environmental screening in order to identify the mode of transmission, evidence for HCW screening is scarce and might not lead to the identification of modes of transmission. Further studies are needed to better understand CI in different settings and, finally, develop guidance on when and how to best perform OI."

Reference: Büchler AC, et al. Outbreak investigations after identifying carbapenem-resistant Pseudomonas aeruginosa: a systematic review. Antimicrobial Resistance & Infection Control. Volume 12, article number 28 (2023).