Complex sentence: Bacteriophage T7 is a phage capable of infecting susceptible bacterial cells it infects most strains of Eschercia Coli (including O157: H7, the strain that causes most food poisoning).
Split into simpler sentences: Bacteriophage T7 is a phage capable of infecting susceptible bacterial cells. It infects most strains of Eschercia Coli (including O157: H7, the strain that causes most food poisoning).