[Diagnostic bacteriophage V32 as a tool for the rapid identification of Escherichia coli serogroup O₁₅₇.]

Bacteriophage V32, a representative of bacterial viruses of the Myoviridae family Ounavirinae subfamily, is proposed for search and identification of E. coli O₁₅₇ serogroup, including Shiga-toxin producing E. coli O₁₅₇:H₇ (STEC O₁₅₇:H₇), among cultures of enterobacteria from the primary seeding of the material studied. Phage genome containes a linear double-stranded DNA of 87875 base pairs with G/C-content of 38.9% and includes 132 open reading frames (ORF). In the genome, there are no determinants of antibiotic resistance, virulence genes of STEC and other well-known pathogroups of E. coli. It has been established that phage V32 has lytic activity against all studied cultures of E. coli O₁₅₇ serogroup (n=183) isolated from people and farm animals in various regions of the Russian Federation, as well as in Japan and Italy. At the same time, the phage lyses only 6 of 182 strains (3.3%) of E. coli not belonging to the O₁₅₇ serogroup and is not active against strains of other enterobacteria. That is, the phage has a high specificity. The use of bacteriophage V32 as a diagnostic tool is a highly efficient, fast, cheap and simple method for identifying E. coli serogroup O₁₅₇, including the serotype E. coli O₁₅₇: H₇, in any bacteriological laboratory without special equipment and special training of performers.