Characterization of Aeromonas Strains Isolated from Adult Patients with Diarrhea and Aquatic Environments - Beijing Municipality, China, 2016-2022.

Introduction: Aeromonas is widely distributed in aquatic environments. This study describes the pathogenic characteristics of Aeromonas isolated from adult diarrhea patients and aquatic environments in Beijing, China.

Methods: Aeromonas isolates from patients with diarrhea and river water samples were assessed using whole-genome sequencing (WGS) and antibiotic resistance profiling.

Results: In total, 38 Aeromonas isolates were collected. Among these, 13 isolates were from patients with common clinical symptoms, including diarrhea, abdominal pain, and nausea. Four of 13 Aeromonas-positive patients were co-infected with other intestinal pathogens. Patient-derived Aeromonas isolates showed high resistance to ampicillin, ampicillin-sulbactam, nalidixic acid, and tetracycline, whereas water-derived isolates showed high resistance to ampicillin, ampicillin-sulbactam, and nalidixic acid. Phylogenetic analysis revealed seven independent branches, without significant clustering among patient- and water-derived isolates.

Conclusions: This study provides valuable insights into the prevalence and characteristics of Aeromonas. The intertwined distribution of patient- and water-derived isolates in the phylogenetic tree deserves attention.