P1-54 Isolation and Characterization of Bacteriophages for Escherichia coli O157:H7

Monday, July 23, 2012
Exhibit Hall (Rhode Island Convention Center)
Jin-Young Kim, Gachon University, Sung-nam, South Korea
Hye-Lim Yoo, Gachon University, Sung-nam, South Korea
Young-Duck Lee, Gachon University, Kyunggi-Do, South Korea
Jong-Hyun Park, gachon university, sung-nam, South Korea
Introduction:  Escherichia coli O157:H7 is an important human pathogen causing diarrhea, hemolytic-uremic syndrome, and hemorrhagic colitis. It has been detected in various food materials and products including cabbages, sprouts, ground beef, and vegetable juices. However, there are many difficulties in removing the pathogen.

Purpose:  This study concerns the isolation of bacteriophage from cattle feces, characterization of stability, host range and morphology, and biocontrol for E.coli O157:H7 in vegetable products by using cocktail of the bacteriophages.

Methods:  The stability test was performed under bacteriophage exposure to the diverse pH, alcohol, and heat conditions. The biocontrol experiment was conducted through comparing the number of viable E.coliO157:H7 in the vegetable juice and the surface of cabbage (2-3cm²) by using cocktail of the bacteriophages.

Results:  Four bacteriophages(ECP1, ECP2, ECP3, ECP4) were isolated from the cattle feces, and those showed high rate of infection to only 9 species of E. coli O157:H7 among 77 species of E. coli, and Salmonella spp. Morphological analysis by TEM indicated that all the bacteriophages belonged to Siphoviridae family. The burst sizes for every bacteriophages showed differences and those were about 40-100 PFU. all of bacteriophages were stable at pH2-pH11 and 70% alcohol concentration, however, they became disappeared at 70°C for 20 minutes. The bacteriophage cocktail, which is mixture of four bacteriophages, of isolation effectively prevented the growth of E.coliO157:H7 in the vegetable juice and surface of cabbage at 37°C in 5 hours.

Significance: Therefore, the host-specific bacteriophage to E.coli O157:H7 would help to control the pathogen in the vegetable products and probably in various foods.