Molecular and Genetic Characterization of Colicinogenic Strains Active against Shiga Toxin-Producing O157:H7.

The objective of this work was to molecularly and genotypically characterize and test the inhibitory activity of six colicinogenic strains (ColEc) and their partially purified colicins against STEC O157:H7 isolated from clinical human cases. Inhibition tests demonstrated the activity of these strains and their colicins against STEC O157:H7. By PCR it was possible to detect colicins Ia, E7, and B and microcins M, H47, C7, and J25. By genome sequencing of two selected ColEc strains, it was possible to identify additional colicins such as E1 and Ib. No genes coding for and were detected after analyzing the genome sequence. The inhibitory activity of ColEc against STEC O157:H7 used as an indicator showed that colicins are potent growth inhibitors of O157:H7, being a potential alternative to reduce the presence of pathogens of public health relevance.