ARS | Publication request: Biocontrol of Escherichia coli O157:H7 using a bacteriophage cocktail in laboratory media

Submitted to: Annual Meeting of the Institute of Food Technologists
Publication Type: Abstract Only
Publication Acceptance Date: March 10, 2009
Publication Date: June 8, 2009
Citation: Boyacioglu, O., Sulakvelidze, A., Sharma, M., Ahmedna, M., Goktepe, I. 2009. Biocontrol of Escherichia coli O157:H7 using a bacteriophage cocktail in laboratory media. Annual Meeting of the Institute of Food Technologists. 2009 Institute of Food Technologies Annual Meeting Technical Program Book of Abstracts.

Technical Abstract: Bacteriophages are natural enemies of bacteria, and therefore, logical candidates to evaluate as antibacterial agents for the control of foodborne pathogens. The effect of a bacteriophage treatment on the prevention of E. coli O157:H7 growth was investigated in Tryptic Soy Broth (TSB) laboratory media. E. coli O157:H7 strains RM1918, RM4406, RM4688, and RM4407 were cultured overnight in TSB. Fresh TSB was inoculated with EHEC and phage cocktail in the following concentrations respectively; 104/107, 104/108, and 105/108 CFU and PFU per ml. Final ratios of phage/EHEC tested in TSB were 1000/1 and 10000/1. Tubes containing host bacteria and phages were incubated at either 4 or 37 deg C. EHEC counts were made at 2, 24, and 48 h on Sorbitol MacConkey (SMAC) Agar. All tubes incubated at 4 deg C had significant reduction in EHEC counts (e.g., 4 log vs. control). Phage treatment significantly reduced the number of EHEC count by 4 log compared to control incubated at 37 deg C after 2 h. However, same phage treatment exhibited only up to 1 log reduction against EHEC at 37 deg C after 24 and 48 h. RM1918 strain was the most susceptible to the phage cocktail treatment both at 4 and 37 deg C. These results show that EHEC-specific phage cocktail used in this study is effective in controlling E. coli O157:H7 in TSB at 4 deg C. Future studies will concentrate on investigating the effect of the phage cocktail on E. coli O157:H7 strain RM1918 on fresh leafy greens.