Virulence Factor Profiles of Escherichia coli O157:H7 Bacteriophage Isolates from Sewage and Livestock Stools

Abstract

The aim of study was to investigate the virulence profile of Escherichia coli O157:H7 bacteriophagesisolated from sewage and livestock stools. Among 23 E. coli O157:H7 bacteriophages, 14 strains were isolatedfrom sewage and 9 were from animal stools collected from 10 livestock farms in Korea. For each bacteriophage DNAsample, the presence of stx1, stx2, eae, aafII, ial, elt, estI, estII, astA, afa, and cnf was examined by polymerase chainreaction. The detection rate of eae, stx2, estI, astA, and ial was 100%, 69.6%, 13.0%, 13.0%, 8.7%, respectively. While all E. coli O157:H7 bacteriophages isolated from stools carried eae+stx2, stx2+eae, eae+astA, eae,stx2+eae+estI, eae+estI, stx2+eae+ial, and eae+ial were observed in bacteriophages isolated from sewage. As severalplasmid-carrying virulence factors (estI, astA, and ial) were found in E. coli O157:H7 bacteriophages obtainedfrom sewage and stools, the microbial safety of bacteriophages should be investigated in further study.