Isolation and characterization of Escherichia coli O157:H7 12900 mutants resistant to phage ; CEV2; 120; 6 and 65.

MARÍA C. ARISTIMUÑO FICOSECO; MARÍA J. OLAYA PASSARELL; ELVIRA M. HÉBERT; RAÚL R. RAYA

Villa Carlos Paz

Congreso; VI Congreso – Sociedad Argentina de Microbiología General; 2009

Sociedad de Microbiología General

Escherichia coli O157:H7 is an endemic pathogen causing a variety of human diseases including mild diarrhea, hemorrhagic colitis, hemolytic-uremic syndrome, and thrombotic purpura, is carried by wild and domestic animals without symptoms of infection. The main source of infection in humans is the consumption of contaminated and poorly cooked meat. The reduction or elimination of this pathogen from its host environment could greatly reduce human exposure and as such be key in disease prevention. Our group is exploring the role of a cocktail of bacteriophages as a strategy to eliminate or control the presence of this pathogen in food. In this work, mutants of thestrain E. coli O157:H7 12900 resistant to four phages (Φ CEV2, Φ 120, Φ 6 and Φ 65) were isolated and characterized. Cross infection experiments showed that the four phages recognized different receptors in the sensitive cells: phages Φ 120, Φ 6 and Φ 65 recognize the same receptor which is distinct to the receptor FhuA recognized by phage Φ CEV2. All the mutants isolated, except those resistant to phage Φ 6, were confirmed to be adsorption mutants.Our results suggest that at least two of the four phages (i.e., Φ CEV2 and Φ 120) could be considered in the design of a cocktail of bacteriophages to be applied in the biocontrol of E. coli O157:H7.