Predicted endolysins from phages with broad lytic activity against Shiga toxin producing Escherichia coli of diverse serogroups

JUÁREZ ANA ELISA; RODRÍGUEZ VICTORIA A.; PASCAL STEFANÍA; DUALDE MELANY; KRÜGER ALEJANDRA; LUCCHESI PAULA M. A.

Oxford

Conferencia; 13th International Conference | Hybrid Phages | 2023 Bacteriophage in Medicine, Food and Biotechnology; 2023

Shiga toxin-producing Escherichia coli are important causative agents of foodborne outbreaks. They can cause serious illnesses such as haemolytic uraemic syndrome. The use of phages and their enzymes are novel strategies which show a high antibacterial potential. Among these enzymes are the endolysins, used by double-stranded DNA phages to degrade the cell wall at the end of their virulent cycle. Endolysins can be classified according to their capacity to cleave linkages in the peptidoglycan layer as glycosidases, amidases, and endopeptidases. In this work, phages isolated from the dairy environment and minced meat were chosen for genome characterization. Previous studies have shown the potential of these phages to lyse strains belonging to different relevant STEC serogroups. DNA was purified with a commercial kit from high-titer stocks, and sequenced using Illumina technology. Ten contigs containing complete phage genomes were characterized. Virus genera were assigned using the software Kraken. Genomes were annotated with RAST and putative endolysins were screened with BLAST, Interpro, Uniprot and HHpred. A molecular phylogenetic analysis of the predicted endolysins was performed by maximum likelihood method conducted in Mega 7. Seven different genomes were further characterized corresponding to different genera: Tequatrovirus (3), Vequintavirus (2), Mosigvirus (1) and Gamaleyavirus (1). Predicted endolysins were analysed and showed to encode six different amino acid sequences. The enzymatically active domains belonged to the glycoside hydrolase family 24 (IPR001296) except one that corresponded to the glycoside hydrolase family 108 (IPR008565). The phylogenetic tree grouped endolysins in accordance to the phage genus. In conclusion, this work showed diversity in the phages we isolated against STEC and also in the endolysins they encode. Further studies will be performed to continue their characterization as antimicrobial agents against this pathogen.