Integrated study on the occurrence and genomic features of Escherichia albertii in environmental water and raccoons in Japan
Year: 2026
Type: article
Abstract: ABSTRACT Escherichia albertii is an emerging zoonotic pathogen that causes intestinal diseases in humans and has been linked to several outbreaks, particularly in Japan. To better understand its environmental ecology and transmission dynamics, we conducted integrated surveillance of environmental water and wild raccoons in Osaka, Japan. E. albertii was frequently detected in river water (76.6%) and raccoons (57.7%) using species-specific PCR. Sequential water sampling at two river locations, performed three times at 30-min intervals, consistently yielded PCR-positive results, suggesting that E. albertii could be detected repeatedly at the same sites despite ongoing water flow. Further analysis indicated the continued detectability of certain E. albertii clones together with additional genotypes. Whole-genome sequencing of 147 strains found that all strains harbored virulence genes associated with clinical strains, along with substantial genomic diversity, overlapping phylogeny, and clonal relationships between strains from both sources. Notably, one raccoon strain and one water strain, collected in the same city and period, differed by fewer than 20 single-nucleotide polymorphisms and showed only a single-band difference in pulsed-field gel electrophoresis, suggesting possible inter-source transmission. Moreover, some environmental and raccoon strains were closely related to human clinical strains, including one linked to a large outbreak in 2017. These findings suggest that E. albertii is widely distributed in aquatic environments and wildlife in Japan and has the potential to cause human infections. This study provides new insights into the ecology and public health risks of E. albertii , highlighting the importance of a One Health approach to monitor this emerging pathogen. IMPORTANCE Understanding how zoonotic pathogens circulate in the environment is essential for preventing emerging infectious diseases. E. albertii is increasingly recognized as a clinically relevant, emerging foodborne pathogen with global distribution. However, its ecological reservoirs, environmental persistence, and transmission dynamics remain poorly understood. This study is the first report to demonstrate a high prevalence and repeated detectability of E. albertii in environmental water and to show its genetic links among strains isolated from environmental water, wild raccoons, and human clinical cases. These findings improve our understanding of the environmental ecology of E. albertii and suggest its potential for transmission across environmental, animal, and human interfaces. The results underscore the importance of a One Health-based surveillance strategy to effectively monitor and control this pathogen. Furthermore, this work provides a basis for future investigations into environmental sources of bacterial zoonotic agents.
DOI: 10.1128/aem.00076-26
Institutions: Osaka Prefecture University, Osaka Metropolitan University
Language: English
Subfield: Endocrinology
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W7140201724