Three New <i>Escherichia coli</i> Phages from the Human Gut Show Promising Potential for Phage Therapy

<div><p>With the emergence of multi-drug resistant bacteria the use of bacteriophages (phages) is gaining renewed interest as promising anti-microbial agents. The aim of this study was to isolate and characterize phages from human fecal samples. Three new coliphages, ɸAPCEc01, ɸAPCEc02 and ɸAPCEc03, were isolated. Their phenotypic and genomic characteristics, and lytic activity against biofilm, and in combination with ciprofloxacin, were investigated. All three phages reduced the growth of <i>E</i>. <i>coli</i> strain DPC6051 at multiplicity of infection (MOI) between 10⁻³ and 10⁵. A cocktail of all three phages completely inhibited the growth of <i>E</i>. <i>coli</i>. The phage cocktail also reduced biofilm formation and prevented the emergence of phage-resistant mutants which occurred with single phage. When combined with ciprofloxacin, phage alone or in cocktail inhibited the growth of <i>E</i>. <i>coli</i> and prevented the emergence of resistant mutants. These three new phages are promising biocontrol agents for <i>E</i>. <i>coli</i> infections.</p>