The occurrence of Morganella morganii caused large death in cultured American bullfrog (Rana catebeiana)

Abstract

Morganella morganii is an important human opportunistic pathogen. It is considered to be an important trafficker of the drug resistance gene from the environment to the clinically important bacteria and a potential role in aquatic pathogens, there are few reports of infections in cultured amphibians, and the pathogenicity of the bullfrog is unknown. Here, we report the large death of cultured bullfrog by natural infection, as well as drug resistance, pathogenesis, and phylogenetic relationships with strain isolated from environmental and clinical samples from various locations. The bacterium was isolated and identified as M. morganii by 16S rRNA sequencing. Experimentally infected bullfrog shows similar clinical manifestations and illustrating the virulence of the strain. The LD₅₀ was determined to be 2.4 × 104 colony forming units (CFU)/mL. This is the first description of M. morganii natural infection and its pathogenesis in bullfrog, which also presents potential risks to animal and human health.