What we can and cannot see from the surveillance for drug-resistant Pseudomonas aeruginosa - Findings from the evaluation of surveillance system for multidrug-resistant P. aeruginosa infections in Japan

Introduction Antimicrobial resistance of Pseudomonas aeruginosa is a global health concern, and some countries and regions have been monitoring drug resistance in P. aeruginosa with various surveillance systems . Japan has a national sentinel surveillance for multidrug-resistant P. aeruginosa (MDRP) infections, the sites of which are designated by prefectures, and we are seeing a decreasing trend in the number of MDRP reports in recent years. We evaluated the national surveillance system to verify whether this decreasing trend is true and discussed future directions of the surveillance. Methods We conducted a cross-sectional study to evaluate the surveillance system for MDRP infections and discussed its usefulness in 2023. We used a quantitative method to analyze characteristics of reports on MDRP infections from designated sentinel sites (DSSs) between 2013–2022. Additionally, we sent a questionnaire to identifiable DSSs (target DSSs) requesting data on accurate numbers of MDRP infections between 2018–2022. We conducted face-to-face interviews with surveillance system stakeholders as a qualitative method. Results In total, 1,666 cases of MDRP infections were reported by 463 target DSSs between 2013-2022. We obtained valid responses to the questionnaire survey from 229 target DSSs (49.5%). From 2018 to 2022, these sites reported 275 cases as MDRP infections, of which 182 were accurate cases of MDRP infection, with both numbers decreasing over time. False reporting or underreporting of MDRP infections was common, resulting in a positive predictive value of 0.44 and sensitivity of 0.65 for reports in the national sentinel surveillance. The interviews highlighted the difficulties this surveillance system has in timely detection, accurate reporting, and international comparison of surveillance data. Conclusion Our evaluation indicated that current sentinel surveillance for MDRP infections fairly captured the true decreasing trend in Japan. As the epidemiology of drug-resistant P. aeruginosa is changing, the direction of the national policy may differ according to the public health needs. The surveillance system also needs to be modified based on the policy, the candidates of which may be a notifiable disease surveillance for MDRP infections to respond to outbreaks, or sentinel surveillance for carbapenem-resistant P. aeruginosa infections to facilitate antimicrobial stewardship and international comparison.