Background/Objectives: The global spread of carbapenem-resistant Pseudomonas aeruginosa (CRPA) warrants collaborative action. Guidance should come from integrated One Health surveillance; however, a surveillance strategy is currently unavailable due to insufficient knowledge on the sources and transmission routes of CRPA. The aim of the SAMPAN study (“A Smart Surveillance Strategy for Carbapenem-resistant Pseudomonas aeruginosa”) is to develop a globally applicable surveillance strategy. Methods: First, an international cross-sectional study will be conducted to investigate CRPA in clinical and environmental settings in Rotterdam (The Netherlands), Rome (Italy), and Jakarta (Indonesia). Screening cultures and risk factor questionnaires will be taken from healthy individuals and patients upon hospital admission. Clinical CRPA isolates will also be included. Additionally, samples will be taken twice from wet hospital environments and monthly from the hospitals’ (drinking) water system, hospital and municipal wastewater treatment plants, and receiving rivers. Whole-genome sequencing will be performed to characterize CRPA isolates and determine the genetic relatedness among the isolates from different reservoirs. Findings from the cross-sectional study, combined with expert elicitation using a Delphi method, will serve as the input for the surveillance strategy. Conclusions: The SAMPAN study will provide a broader understanding of the sources and transmission routes of CRPA. Therewith, the development of a globally applicable smart surveillance strategy will be made possible, delivering information that is needed to guide actions against the spread of CRPA.

Background: Carbapenem-resistant Pseudomonas aeruginosa (CRPA) poses a global health risk, yet there is insufficient knowledge about its sources and transmission routes within an integrated One Health framework. This study aimed to investigate CRPA presence and dynamics at the human-water interface inside and outside hospitals in three major cities located in different climatic zones. Methods: This cross-sectional study was conducted in Rotterdam (The Netherlands), Rome (Italy), and Jakarta (Indonesia) between March 2022 and June 2024. Samples were collected from humans, hospital environments, and various water sources. CRPA isolates underwent sequencing to determine carbapenemase gene presence and their genetic relatedness. Primary outcomes included CRPA carriage in healthy individuals and newly hospitalized patients, CRPA prevalence in hospital environments, CRPA concentrations in aquatic environments, and the frequency and transmission likelihood within epidemiological clusters. Findings: CRPA carriage was detected in 0·5% (1/194) of healthy individuals from Rotterdam, 0·0% (0/245) from Rome, and 0·8% (2/250) from Jakarta. Among patients, CRPA carriage differed significantly across cities (P<0·001), with 0·4% (2/469) in Rotterdam, 0·3% (1/363) in Rome, and 4·8% (28/584) in Jakarta. In wet hospital environments, CRPA prevalence ranged between 0·0% (Rome) and 13·4% (Jakarta). CRPA concentrations were highest in hospital wastewater and remained detectable in treated effluent of municipal wastewater treatment plants (mWWTP) and the receiving river in all cities. Carbapenemase genes were detected in 25·9% (100/386) of isolates. CRPA isolates identified in the clinical setting clustered with those from mWWTP influent or effluent (Rotterdam) or the river (Jakarta). High genetic diversity, overall and within reservoirs, was observed among isolates. Interpretation: The substantial presence of CRPA in environmental reservoirs, along with the cross-over between them, may pose a public health risk, and warrant mitigation strategies. To prevent CRPA transmission within hospitals and limit cross-sectoral transmission, robust infection prevention and control measures, alongside effective wastewater treatment, are essential.