Impact of the COVID-19 Pandemic on the Surveillance of Antimicrobial Resistance

Background: The coronavirus disease 2019 (COVID-19) pandemic has brought about major changes in the medical field; the impact of the pandemic on antimicrobial resistance (AMR) is a major concern. Methods: We utilized comprehensive surveillance data, collected in a national AMR surveillance program, which included a total of 16·7 million samples of 5·9 million tested patients from >1,300 hospitals. We compared the number of patients and isolation rate of five types of pathogens , including antimicrobial susceptible and resistant bacteria of S. aureus, S. pneumoniae, E. coli, K. pneumoniae, and P. aeruginosa between 2019 and 2020. Findings: The number of patients and the isolation rate of S. aureus and methicillin-resistant S. aureus decreased slightly, those of S. pneumoniae and penicillin-resistant S. pneumoniae decreased by 60%, and third-generation cephalosporin-resistant K. pneumoniae increased compared to the previous year. Further, the isolation rate of the remaining pathogens apparently increased, although the number of patients decreased. The phenomenon was due to substantial decrease in the total number of tested patients (i.e., the denominator of the isolation rate), which was larger than that of the number of patients. Consistent results were obtained when the same data were re-aggregated according to the procedure defined by the World Health Organization Global Antimicrobial Resistance Surveillance System, demonstrating the general importance of this problem. Interpretation: Surveillance data during the COVID-19 pandemic must be carefully interpreted based on examination of both the numerator and denominator; the background factors that influence the denominator should be considered. Funding: This study was supported by the Research Program on Emerging and Re-emerging Infectious Diseases from the Japan Agency for Medical Research and Development (AMED) under grant number JP19fk0108061. Declaration of Interest: None to declare. Ethical Approval: This study was approved by the Ministry of Health, Labour and Welfare (approval number 0219–7) according to Article 32 of the Statistics Act.