Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2023

Isolation and characterisation of bacteriophage to treat Acinetobacter baumannii and Burkholderia cepacia complex antimicrobial-resistant infections (#120)

Jack S. Canning 1 2 , Daniel R. Laucirica 2 , Kak Ming Ling 2 3 , Rohan Flint 1 2 , Renee N. Ng 1 2 , Stephen M. Stick 2 4 5 , Anthony Kicic 2 3 4 5 , AREST CF 2 4 6 7 , WAERP 2 8
  1. Division of Infection and Immunity , Division of Infection and Immunity, School of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Western Australia, Perth, Australia, Perth, WA, Australia
  2. Wal-Yan Respiratory Research Centre , Wal-Yan Respiratory Research Centre, Telethon Kids Institute, The University of Western Australia, Crawley, WA, Australia, Perth , WA, Australia
  3. School of Population Health, School of Population Health, Curtin University, Bentley, WA, Australia., Perth , WA, Australia
  4. Department of Respiratory and Sleep Medicine, Department of Respiratory and Sleep Medicine, Perth Children’s Hospital, Nedlands, WA, Australia, Perth, WA, Australia
  5. Centre for Cell Therapy and Regenerative Medicine, Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, The University of Western Australia and Harry Perkins Institute of Medical Research, Nedlands, WA, Australia, Perth, WA, Australia
  6. Murdoch Children's Research Institute, Murdoch Children's Research Institute, Melbourne, VIC, Australia, Melbourne , VIC , Australia
  7. Dept of Paediatrics, Dept of Paediatrics, University of Melbourne, Melbourne, VIC, Australia, Melbourne, VIC, Australia
  8. St. John of God Hospital, St. John of God Hospital, Subiaco, WA, Australia, Perth , WA, Australia

Infection with antimicrobial resistant bacteria is a significant source of morbidity amongst those with underlying respiratory conditions. Pathogens which can cause respiratory infection but readily develop antibiotic resistance, albeit rarely, include Acinetobacter baumannii and Burkholderia cepacia complex (BCC). High levels of acquired and intrinsic resistance makes eradicating these pathogens difficult, and current treatment regimens involve multiple courses of high dose medications with toxic side effects (1). In the pursuit of new or alternative therapeutics, bacteriophages (phages), viruses which infect bacteria, have gained renewed interest. This project aims to establish and expand a pipeline of A. baumannii and BCC phage isolation and characterisation, and then assess the efficacy and safety of phage treatment in several in-vitro models. Wastewater was filtered, chemically treated and assessed for phage activity using the gold standard whole-plate double overlay method, and plaques formed by bacteriophage were picked and purified. Initial screens have identified 210+ phages with activity against 14 A. baumannii clinical isolates and 134+ against 20 BCC isolates. The bactericidal host range for each phage was assessed by spotting neat phage lysate onto a lawn of a bacterial host. Lytic activity was assigned as either “Complete” “Partial” or “No Lysis” based on visual inspection. Host range assessment revealed a relatively narrow host range for both pathogens, and many phages only possessed partial lytic activity against many of the clinical strains. Phages were ranked from most-to-least broad host range and 38 BCC phage and the top 30 A. baumannii phages were selected for further characterisation. Phages were then imaged using Transmission Electron Microscopy (TEM), allowing structural taxonomic assessment of phages into families. TEM revealed significant diversity of isolated phages, including those from the Myoviridae, Siphoviridae and Podoviridae families. Future directions will look at genomic sequencing for both phage and clinical isolates and assess phage in a clinically relevant differentiated airway epithelial cell model to assess the efficacy and tolerability of phage treatment.