Isolation, characterization and in vivo efficacy of Escherichia phage myPSH1131

PLoS One. 2018 Oct 24;13(10):e0206278. doi: 10.1371/journal.pone.0206278. eCollection 2018.

Abstract

Phage therapy is the use of lytic bacteriophages to cure infections caused by bacteria. The aim of this study is to isolate and to characterize the bacteriophages against Escherichia coli isolated from clinical samples. For isolation of bacteriophages, water samples were collected from the Ganges River, and phage enrichment method was followed for phage isolation. Microbiological, genomic and lyophilization experiments were carried out to characterize the bacteriophage. Galleria mellonella was used to study the potential of phages against E. coli infection. Escherichia phage myPSH1131 belonging to Podoviridae family and found to have broad host range infectivity (n = 31) to infect Enterohemorrhagic E. coli (n = 9), Enteropathogenic E. coli (n = 6), Enterotoxigenic E. coli (n = 3), Enteroaggregative E. coli (n = 3), Uropathogenic E. coli (n = 9) and one unknown E. coli. The genome size is 76,163 base pairs (97 coding regions) and their genes show high similarity to SU10 phage. Lyophilization studies showed that the use of 1M sucrose, 2% gelatin and the combination of both 0.5M sucrose plus 1% gelatin could restore phage viability up to 20 months at 4°C. For in vivo studies, it was observed that a single phage dose can reduce the E. coli infection but to achieve 100% survival rate the infected larvae should be treated with three phage doses (20 μL, 10(3) PFU/mL) at 6 hours interval. The characterized Escherichia phage myPSH1131 was found to have broad host range activity against E. coli pathogens and in vivo studies showed that multiple doses are required for effective treatment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Escherichia coli / virology*
  • Escherichia coli Infections / prevention & control*
  • Moths / microbiology*
  • Phage Therapy*
  • Podoviridae / classification
  • Podoviridae / isolation & purification
  • Podoviridae / pathogenicity*

Grants and funding

This work was supported by the Vellore Institute of Technology in the form of a VIT Seed Grant. This work was partly supported by Swedish Research Council with grants to CSL (Grant No. 2012-02889 and 2017-01327). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.