Inactivation of extraintestinal pathogenic E. coil suspended in ground chicken meat by high pressure processing and identification of virulence factors which may affect resistance to high pressure

Extraintestinal pathogenic Escherichia colt (ExPEC) are responsible for urinary tract infections, inflammatory bowel disease, sepsis and meningitis. Retail poultry meat has been identified as the main reservoir for ExPEC in food. Information regarding ExPEC virulence factor (VF) or antibiotic resistance (AR) involvement with resistance to high-pressure inactivation in food is lacking. In this study we inoculated ground chicken meat with 22 individual isolates of clinical uropathogenic E. coli (UPEC) and newborn meningitis causing E. colt (NMEC), and isolates from retail chicken meat. We then determined their high-pressure inactivation kinetics (D-10-value). The mean D-10-value for all isolates (n = 22) was 3.26 min at 400 MPa. The mean D-10-value for the UPEC, NMEC, chicken isolates were 5.0, 1.3, 2.23 and 4.98 min at 400 MPa, respectively. The D-10 varied widely between the 22 isolates. The mean D-10-value for the clinical isolates was 3.33 vs. 3.15 for the non-clinical isolates. The NMEC strains were more sensitive to HPP. ExPEC lacking chuA, cnf1, sinH, papG, hlyA, vat; yncD were more resistant to HPP, indicating ExPEC VF could play a role in high pressure resistance. HPP at 600 MPa for 3 min resulted in > 6 log(10) reductions for UPEC, NMEC, and retail chicken product isolates.