Oral Presentation Australian Society for Microbiology Annual Scientific Meeting 2019

Antibiofilm activities of pentacyclic triterpenoids against methicillin-resistant and biofilm-forming Staphylococcus aureus (MRSA) (#40)

Pooi Yin Katrina Chung 1 , Ming Yi Gan 1 , Beek Yoke Chin 1
  1. International Medical University, Kuala Lumpur, FEDERAL TERRITORIES, Malaysia

Methicillin-resistant Staphylococcus aureus (MRSA) has been constantly evolving and developing resistance against conventional antibiotics. One of the key features of MRSA that enables it to develop resistance to antibiotics and host immune system is its ability to form biofilm. Biofilm acts as a protective barrier and provides protection for the cells within the biofilm. Current treatment for biofilm-associated infections mainly involves surgical removal of the colonised implants which may further expose patients to hospital-associated infections. Hence, alternative therapeutics are urgently needed. Pentacyclic triterpenoids have long been used in traditional medicine and possess a wide range of pharmacological effects. In previous studies, the antimicrobial activity and mechanisms of action of three known compounds, α-amyrin, betulinic acid and betulinaldehyde against planktonic cells of MRSA were determined and elucidated. However, the antibiofilm effects of these compounds are still poorly understood. Hence, this study was carried out to evaluate the antibiofilm activities of the three compounds, as well as combinations of these compounds and oxacillin or vancomycin in pre-formed biofilms using the crystal violet and resazurin assays. The results showed α-amyrin significantly reduced the biofilm in the reference strain of biofilm-forming MRSA, while vancomycin showed significant reduction in the metabolic activity. There were no synergistic effects on the biofilm eradication in the selected combinations of the compounds and antibiotics evaluated.