In-vitro efficacy of polyhexamethylene biguanide - graphene oxide nanoparticles against corynebacterium pseudotuberculosis isolates

Caseous lymphadenitis (CLA) is a contagious and zoonotic disease caused by Corynebacterium pseudo tuberculosis ( C. pseudo tuberculosis) affecting small ruminants all over the world, causing economic losses to farmers. The treatment has only been partially effective, in part, due to formation of thick encapsulated abscess that provided protective nature from the treatment and immune system, in the infected animal. Therefore an alternative therapy that could be formulated against the thick abscess would be needed. This research explores the potential of polyhexamethylene biguanide (PHMB) and graphene oxide (GO) nanoparticles as a potential treatment, by demonstrating their bactericidal effects against C. pseudotuberculosis in-vitro using the time kill assay. The result demonstrated that PHMB alone is effective in comparison to GO alone, or combination of PHMB+GO at three hours exposure time. This could be due to the interaction between GO and PHMB that hinders PHMB activities against the bacteria. In conclusion, this study demonstrates that PHMB alone is effective against C. pseudotuberculosis in vitro and has potential to be further tested in vivo before it can be developed for the CLA treatment.
Keyword: Caseous lymphadenitis, Corynebacterium pseudotuberculosis, Polyhexamethylene biguanide, Graphene Oxide