Characterization of Aquatic <i>Acinetobacter baumannii</i> during the COVID-19 Outbreak in Wuhan, China

Acinetobacter baumannii is an emerging nosocomial pathogen that poses a significant challenge to healthcare systems. Antibiotics remain the primary approach for treating A. baumannii infections. Clinical strains of A. baumannii may share ecological and genetic links with environmental isolates, particularly in aquatic environments, making the investigation of resistance profiles in environmental strains relevant to developing treatment strategies for A. baumannii-related infections. Metagenomic binning was employed to reconstruct two metagenome-assembled genomes (MAGs) of A. baumannii from surface water samples collected from the Yangtze River during the COVID-19 pandemic. Analyses revealed that these MAGs harbored antibiotic resistance genes associated with β-lactams, multidrug resistance, and tetracyclines. In addition, phylogenetic analysis showed that the assembled A. baumannii strains were closely related to the IC11 clade of clinical A. baumannii isolates, based on a comparison with 28 clinical strains. According to the resistance gene profiles of the MAGs, we found that 2 (13 in total) commonly used antibiotics in China and 20 (29) WHO-recommended “last-resort” antibiotics had potential efficacy in the treatment. The findings underscore the value of environmental surveillance for understanding resistance mechanisms in A. baumannii and informing strategies to mitigate its clinical and public health impact.