Genetically manipulated phages with improved pH resistance for oral administration in veterinary medicine

Sci Rep. 2016 Dec 15:6:39235. doi: 10.1038/srep39235.

Abstract

Orally administered phages to control zoonotic pathogens face important challenges, mainly related to the hostile conditions found in the gastrointestinal tract (GIT). These include temperature, salinity and primarily pH, which is exceptionally low in certain compartments. Phage survival under these conditions can be jeopardized and undermine treatment. Strategies like encapsulation have been attempted with relative success, but are typically complex and require several optimization steps. Here we report a simple and efficient alternative, consisting in the genetic engineering of phages to display lipids on their surfaces. Escherichia coli phage T7 was used as a model and the E. coli PhoE signal peptide was genetically fused to its major capsid protein (10 A), enabling phospholipid attachment to the phage capsid. The presence of phospholipids on the mutant phages was confirmed by High Performance Thin Layer Chromatography, Dynamic Light Scattering and phospholipase assays. The stability of phages was analysed in simulated GIT conditions, demonstrating improved stability of the mutant phages with survival rates 102-107 pfu.mL-1 higher than wild-type phages. Our work demonstrates that phage engineering can be a good strategy to improve phage tolerance to GIT conditions, having promising application for oral administration in veterinary medicine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Animals
  • Bacteriophage T7 / genetics*
  • Bacteriophage T7 / growth & development
  • Bacteriophage T7 / metabolism
  • Capsid Proteins / genetics
  • Capsid Proteins / metabolism
  • Chromatography, Thin Layer
  • Drug Resistance, Viral*
  • Dynamic Light Scattering
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / metabolism
  • Gastrointestinal Tract / virology
  • Genetic Engineering*
  • Hydrogen-Ion Concentration
  • Microscopy, Electron, Transmission
  • Phospholipids / analysis
  • Phospholipids / chemistry
  • Phospholipids / metabolism
  • Porins / chemistry
  • Porins / metabolism
  • Protein Sorting Signals / genetics
  • Temperature
  • Veterinary Medicine

Substances

  • Capsid Proteins
  • Escherichia coli Proteins
  • Phospholipids
  • Porins
  • Protein Sorting Signals
  • PhoE protein, E coli