Isolation of the new E.coli bacteriophage and its characterization

Author: Lana Turmanidze
Keywords: Bacteriophage, Phage therapy, Antibiotic resistance, E.coli
Annotation:

In 1884, the German microbiologist Theodor Escherich discovered the rapidly multiplying bacterium, which he named “Bacterium Coli Commune”, today widely known as E. coli (Escherich, 1988; Shulman et al., 2007; Zimmer, 2008). Infections caused by this bacterium are a global concern. according to World Health Organization studies, there are approximately 2.8 million cases reported annually (Ameer et al., 2022). For many years, antibiotics have been the primary tool of defense against the pathogen. However, incorrect and excessive use of antibiotics, especially after 1950s, has led to the emergence of resistant strains of E. coli. In order to address the challenge of antibiotic resistance, a novel, multifaceted approach is needed. The latter being phage therapy - an alternative therapeutic strategy. The aim of the study is to isolate and characterize a new bacteriophage against E. coli, to describe and compare its properties to an active phage derived from the general microbiology laboratory collection along with their host. To create a therapeutic phage biopreparation, it is essential to know the genetic and biological characteristics of each phage included in the preparation to ensure the broad range and effectiveness of the product. Therefore, we thoroughly examined the characteristics of the bacteriophages, including their morphology, titer via the Gracia and Appelmans method, adsorption on the host cell’s surface, stability at different temperatures, and the lytic spectrum. The host bacterium was identified using the API system, and its antibiotic sensitivity was tested. It was found that E. coli 63 is sensitive to 5 antibiotics. The F1 phage selected from the collection and the vB_E.coli-S1 phage isolated from sewage have different lytic spectra, with the latter being characterized by a broader range of host strains. In terms of binding to the surface of the host cell, the phages differ slightly from each other - adsorption efficiency in 10 minutes was 85% for the F1 phage and 80% for the vB_E.coli-S1 phage. The vB_E.coli-S1 showed stability at high temperatures. Morphologically, the F1 phage belongs to the Myoviridae family, while the isolated vB_E.coli-S1 belongs to the Podoviridae family. Based on the obtained results, we can say that these phages are different from each other.