Potential use of cannabinoids to combat against methicillin-resistant Staphylococcus aureus pneumonia: A pre-formulation study
Pancy Tsz Hei Kwong1, Theerthankar Das2, Jonathon Carl Arnold3, Hak-Kim Chan1 & Philip Chi Lip Kwok1
1Advanced Drug Delivery Group, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, NSW 2006, Australia
2Ingham Institute for Applied Medical Research, Microbiology and Infectious Diseases, School of Medicine, Western Sydney University, NSW 2170, Australia
3Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, NSW 2050, Australia
Summary
Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of hospital-acquired lung infections. MRSA is likely to form a biofilm in the lungs, rendering the infection more difficult to eliminate which often results in treatment failure. Due to the challenges in treating MRSA pneumonia, the administration of high doses of antibiotics frequently leads to severe adverse effects. In this study, potentially more tolerable, non-psychoactive cannabinoids – cannabidiol (CBD), cannabigerol (CBG), and cannabinol (CBN) were investigated for their activity against a MRSA isolate cultured in a biofilm. CBN was discovered to be the most potent candidate with anti-MRSA biofilm activity, shown by reductions in biofilm biomass and bacterial viability. In particular, CBN exhibited efficacy in killing more than 80% of the bacteria in the biofilm at 1 µg/mL, whereas CBD and CBG were less effectively, with 10% and 60% reduction in viability, respectively. Only CBN demonstrated significant biofilm dispersal effect at all concentrations. With their penetration through the extracellular matrix and potent antibiofilm activity against MRSA, cannabinoids present an exciting opportunity for the development of inhalable formulations to treat bacterial pneumonia.