Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2023

Investigating the behaviour and efficacy of bacteriophages using in vitro primary airway epithelial cells (#153)

Kak Ming Ling 1 2 3 , Renee Ng 1 4 , Craig Schofield 1 , Andrew Vaitekenas 1 3 , Stephen Stick 1 2 5 6 7 , Anthony Kicic 1 3 4 6 7 , AREST CF 1 7 8 9 , WAERP - 1 10
  1. Wal-yan Respiratory Centre, Telethon Kids Institute, Nedlands, WESTERN AUSTRALIA, Australia
  2. Centre for Child Health Research, The University of Western Australia, Perth, Western Australia, Australia
  3. School of Population Health, Curtin University, Perth, Western Australia, Australia
  4. School of Biomedical Sciences, The University of Western Australia, Perth, Western Australia, Australia
  5. Division of Paediatrics, Medical School, The University of Western Australia, Nedlands, Western Australia, Australia
  6. Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, The University of Western Australia and Harry Perkins Institute of Medical Research, Perth, Western Australia, Australia
  7. Department of Respiratory and Sleep Medicine, Perth Children’s Hospital, Perth, Western Australia, Australia
  8. Murdoch Children's Research Institute, Melbourne, Victoria, Australia
  9. Department of Paediatrics, The University of Melbourne, Melbourne, Victoria, Australia
  10. St John of God Hospital, Subiaco, Western Australia, Australia

Background: Individuals with chronic lung disease like cystic fibrosis often suffer from persistent bacterial infections, and prolonged antibiotic treatment contributes to antimicrobial resistance (AMR). Bacteriophage (phage) therapy is currently being revisited to treat AMR due to its specificity and lack of documented adverse effects. This study aimed to investigate host-phage-bacteria dynamics in the airway cells. Methods: Primary airway epithelial cells (pAECs) were established and differentiated at air-liquid interface (ALI) prior to inoculating with P. aeruginosa (PAO1, MIC74 and MIC90) over 24 hours to form biofilms. Phages (Kara-mokiny 3 (KM3), Boorn-mokiny 1 (BM1), Minga-mokiny 4 (MM4), and E79) were tagged using SYBR Gold DNA stain, filtered, and added onto airway cultures. The pAECs exposed to tagged phages were sorted using a BD LSR fortessa, and tagged phages were detected using the B530 filter set. Apical and basolateral collected supernatants were measured for IL-8 production and inserts were fixed and stained for various cell structures (ciliated cells, tight junction) and cell function (secretory mucin). Bactericidal activity was measured by viable P. aeruginosa enumeration. Results: Administration of different phage morphotypes, KM3, BM1, MM4, and E79 alone, did not significantly induce IL-8 production by pAECs over 24 h. Exposure of phages KM3 and MM4 to biofilms formed on ALIs culture had significantly reduced bacterial loads at 24 hours post-exposure with KM3 (3.8 x 109 ± SD vs 7.3 x 104 ± SD) and MM4 (3.5 x 109 ± SD vs 1.6 x 108 ± SD), respectively. Furthermore, infected pAECs treated with these phages did not induce additional IL-8 production basolaterally when compared to bacterial infected only pAECs (KM3: 3.9 ± 0.4 x 105, MM4: 3.6 ± 0.5 x 105 vs control:  2.6 ± 1.0 x 105 ). Conclusion: We demonstrated interactions between phages and airway cells in the presence or absence of a bacterial host, suggesting key implications for phage administration, safety, and efficacy.