Exploring phage mechanisms that enhance activity

• Author / Creator

  Kamal, Fatima

• In recent years, there has been a renewed interest in using bacteriophages as an alternate agent for the treatment of multi-drug resistant bacteria. One such highly drug-resistant group of bacteria is the Burkholderia cepacia complex (Bcc), which causes chronic infections in cystic fibrosis (CF) patients. Bcc consist of twenty-two Gram-negative species that are especially problematic because of their person-to-person transmissibility and an ability to generate a rapidly fatal acute infection. Presently, phage therapy is being developed as an alternative treatment for Bcc infections. However, for phage therapy to be most effective, strategies to enhance efficacy of treatment need to be explored. One of the methods we examined was the synergistic effect of certain antibiotics on Bcc phages KS12 and KS14. Phage-Antibiotic Synergy (PAS) was observed for both of the phages as noted by increases in phage plaque sizes and phage titers. A significant increase in the survival of Bcc-infected Galleria mellonella larvae was observed when treated with meropenem or minocycline in combination with phage, as compared to phage or antibiotics alone. Another strategy examined was to test the effects of phage-encoded MazG on phage production. MazG is a pyrophosphohydrolase which can hydrolyse GTP and ATP. MazG encoded by Bcc phages KL1 and AH2 was tested on phage production in overnight cultures of B. cenocepacia C6433 and K56-2. Significantly higher numbers of phages were observed upon infection of stationary phase Bcc cells transformed with cloned KL1 or AH2 mazG. This indicates that MazG can provide an advantage to phages infecting slow-growing Bcc bacteria, which likely exist in stationary phase during chronic infections. These findings suggest that different strategies can be employed to increase the activity of phages and thus can be used to enhance the efficacy of phage treatment.

• Subjects / Keywords

  • Phage-Antibiotic Synergy
  • Bacteriophage
  • MazG
  • Burkholderia cepacia complex
  • Phage therapy

• Graduation date

  Fall 2017

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3GF0NC4D

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.