◆Research findings by Professor Ken Ihara and colleagues Faculty of Agriculture in the School of Natural Sciences have been published in the journal *Water Research*
Release Date:
Survey on the Prevalence of Antibiotic-Resistant Bacteria in Urban Areas Using Manhole Covers
—Proposing a Method to Monitor Drug-Resistant Bacteria in Urban Areas by Applying Sewage Surveillance to Manholes—
The results of a joint research project between Professor Ken Ihara’s research group Faculty (Natural Sciences) and researchers from Kyoto University and the University of Tokyo were published online in the journal *Water Research* on June 30, 2025.
Since the onset of the COVID-19 pandemic, wastewater surveillance—a method of assessing community transmission by detecting the novel coronavirus in wastewater samples collected from treatment plants—has garnered global attention and is now being utilized in many countries, including Japan. Furthermore, the application of wastewater surveillance is expanding beyond the novel coronavirus to include the investigation of various pathogenic viruses and drug-resistant bacteria.
Professor Ihara’s research group has become the first in the world to successfully apply sewage surveillance to wastewater samples collected from urban manholes to assess the prevalence of antibiotic-resistant bacteria in the city. From January 2022 to March 2024, the group collected water samples from a total of 33 manholes across a city in Japan and investigated antibiotic-resistant E. coli using both culture methods and PCR-based detection of antibiotic resistance genes.The results revealed a correlation between land use patterns around manholes and the number of drug-resistant bacteria. Furthermore, whole-genome sequencing of drug-resistant E. coli elucidated the genetic characteristics of E. coli producing extended-spectrum β-lactamases (ESBLs) and Enterobacteriaceae producing carbapenemases present in urban sewage, and demonstrated their widespread presence across the city.
These research findings demonstrate that sewage surveillance at manholes is an effective method for assessing the prevalence of drug-resistant bacteria in urban areas, and its future application is anticipated.
[Paper Information]
Title of the paper: Occurrence of antibiotics and antibiotic-resistant bacteria in a Japanese city revealed by wastewater surveillance in the sewer system
Authors: Yu Tang, Ryota Gomi, Haruka Takeuchi, Fumitake Nishimura, Masaru Ihara
Journal title: Water Research, Volume 285, Article number: 124136 (2025)