First report of environmental bla _PAC-1 -carrying Aeromonas enteropelogenes

The blaPAC-1 has been reported in Central Asia and Europe countries like Afghanistan and France in Aeromonas caviae and Pseudomonas aeruginosa strains from animals and patients, respectively. However, there is no record of blaPAC-1-carrying strain from the natural environment, and blaPAC-1-carrying Aeromonas has not been reported in the Asia Pacific. Here, we report the first known enviromental blaPAC-1-carrying Aeromonas enteropelogenes in the world from reservoir water in Singapore. We have performed a comprehensive genetic environment alignment and comparison of blaPAC-1 between our strain and other strains from different countries and sources and found the blaPAC-1 located on a highly conserved gene cluster. We suggest that environmental Aeromonas strains may act as a hidden reservoir involved in the circulating of blaPAC-1. The finding of conserved blaPAC-1 cluster also suggested the existence of multiple transmission pathways of blaPAC-1 in the Asia-Pacific region, involving multiple sources and different species.