Since its initial outbreak in China, in December, 2019, COVID-19 has spread rapidly across the globe. At the time of writing, on April 29, 2020, infections had been confirmed in more than 200 countries and regions and 3,018,681 infections and 207,973 deaths had been recorded. In Japan, the first confirmed case of SARS-CoV-2 infection was reported on January 16, 2020, since when, the number of domestic infections and the death toll have reached 13,852 and 389, respectively, representing exponential increases. Moreover, both domestically and internationally, the shortage of medical resources and the spread of infection among medical personnel, caused by nosocomial transmissions have become problematic. The pathology of COVID-19, including the exact infection route, remains largely unknown. Given the unavailability of an effective cure and vaccine, people are required to respond to this adversity without becoming complacent. The global efforts against the COVID-19 pandemic are ongoing endeavors, far from over. New epidemiological data and clinical findings are emerging on a daily basis, making it critical to always refer to the latest information.

The emergence and spread of antimicrobial resistance (AMR) has become a persistent problem globally. In this study, an ozone treatment facility was established for an advanced hospital wastewater treatment in a core hospital facility in an urban area in Japan to evaluate the inactivation of antimicrobial-resistant bacteria and antimicrobials. Metagenomic DNA-seq analysis and the isolation of potential extended-spectrum β-lactamase (ESBL)-producing bacteria suggested that ozone exposure for at least 20 min is required for the adequate inactivation of DNA and ESBL-producing bacteria. Escherichia coli and Klebsiella species were markedly susceptible to 20-min ozone exposure, whereas Raoultella ornithinolytica and Pseudomonas putida were isolated even after an 80-min exposure. These ozone-resistant bacteria might play a pivotal role as AMR reservoirs in the environment. Nine antimicrobials (ampicillin, cefdinir, cefpodoxime, ciprofloxacin, levofloxacin, clarithromycin, chlortetracycline, minocycline, and vancomycin) were detected at 373 ng/L to 27 μg/L in the hospital wastewater, and these were removed (96–100% removal) after a 40-min treatment. These results facilitate a comprehensive understanding of the AMR risk posed by hospital wastewater and provides insights for devising strategies to eliminate or mitigate the burden of antimicrobial-resistant bacteria and the flow of antimicrobials into the environment. To the best of our knowledge, this is the first report on the implementation of a batch-type, plant-scale ozone treatment system in a hospital facility to execute and evaluate the inactivation of drug-resistant bacteria and antimicrobials.