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

The bla _PAC-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 bla _PAC-1-carrying strain from the natural environment, and bla _PAC-1-carrying Aeromonas has not been reported in the Asia Pacific. Here, we report the first known enviromental bla _PAC-1-carrying Aeromonas enteropelogenes in the world from reservoir water in Singapore. We have performed a comprehensive genetic environment alignment and comparison of bla _PAC-1 between our strain and other strains from different countries and sources and found the bla _PAC-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 bla _PAC-1. The finding of conserved bla _PAC-1 cluster also suggested the existence of multiple transmission pathways of bla _PAC-1 in the Asia-Pacific region, involving multiple sources and different species.