Project description:The enterohemorrhagic Escherichia (E.) coli (EHEC) is a pathogen of great concern for public health and the meat industry all over the world. High economic losses in meat industry and the high cost of the illness evidence the necessity of additional efforts to control this pathogen. Previous studies demonstrated inhibitory activity towards EHEC, of a bioprotective strain, Enterococcus mundtii CRL35, it showing also a specific proteomic response during the co-culture. In the present work additional studies of the EHEC-Ent. mundtii interaction were carried out: i) differential protein expression of E. coli O157:H7 NCTC12900 when growing in co-culture with Enterococcus mundtii in a meat environment, ii) the reciprocal influence between these two microorganisms in the adhesion to extracellular matrix (ECM) proteins and iii) the possible induction of the phage W933, coding for Shiga toxin (Stx1), by the presence of Ent. mundtii CRL35. When compared the co-culture with individual growth, proteomic results showed significant repression of E. coli NCTC12900 proteins related mostly to the metabolism and transport of amino acids and nucleotides. However, statistically significant over expression of EHEC proteins involved in stress, energy production, amino acid metabolism and transcription was observed at 30 h respect to 6 h when EHEC grew in co-culture. On the other hand, EHEC showed a decreased adhesion capacity to ECM proteins in the presence of the bioprotective strain. Finally, Ent. mundtii CRL35 did not induce the lytic cycle of W933 bacteriophage, thus indicating its potential safe use for eliminating this pathogen. Overall, this study expands the knowledge of EHEC- Ent. mundtii CRL35 interaction in a meat environment, as an attempt to find out effective biological strategies to eliminate this pathogen.
