Identification of Corynebacterium ulcerans and Erysipelothrix sp. in Malayan pangolins-a potential threat to public health?

The discovery of severe acute respiratory syndrome-coronavirus-2-like and Middle East respiratory syndrome-coronavirus-like viruses in Malayan pangolins has raised concerns about their potential role in the spread of zoonotic diseases. Herein, we describe the isolation and whole-genome sequencing of potentially zoonotic two bacterial pathogens from diseased Malaysian pangolins ( )- and sp. The newly identified species were designated as P69 and sp. P66. P69 exhibited 99.2% whole-genome nucleotide identity to human bacterial isolate 4940, suggesting that it might have zoonotic potential. Notably, P69 lacked the diphtheria toxin ( ) gene that is widely used in vaccines to protect humans from corynebacterial infection, which suggests that the current vaccine may be of limited efficacy against this pangolin strain. P69 also contains other known virulence-associated genes such as and exhibits resistance to several antibiotics (erythromycin, clindamycin, penicillin G, gentamicin, tetracycline), which may affect its effective control. sp. P66 was closely related to sp. strain 2-related strains, exhibiting 98.8% whole-genome nucleotide identity. This bacterium is lethal in mice, and two commercial vaccines failed to protect its challenge, such that it could potentially pose a threat to the swine industry. Overall, this study highlights that, in addition to viruses, pangolins harbor bacteria that may pose a potential threat to humans and domestic animals, and which merit attention. This study firstly reports the presence of two potentially zoonotic bacteria, and sp., in diseased Malaysian pangolins collected in 2019. The pangolin is lethal in mice and resists many antibiotics. It clustered with a lethal human strain but lacked the diphtheria toxin gene. Diphtheria toxin is widely used as a vaccine around the world to protect humans from the infection of corynebacteria. The lack of the gene suggests that the current vaccine may be of limited efficacy against this pangolin strain. The pangolin sp. is the sister clade of . It is lethal in mice, and two commercial vaccines failed to protect the mice against challenge with the pangolin sp., such that this strain could potentially pose a threat to the swine industry. These findings emphasize the potential threat of pangolin bacteria.