A Combination of Egg Yolk IgY and Phosvitin Inhibits the Growth of Enterotoxigenic Escherichia coli K88 and K99.

Abstract

Enterotoxigenic Escherichia coli (ETEC) is the main cause of fatal diarrhea in piglets during the first week of life and over the time of weaning. Pathogenesis of ETEC-causing diarrhea involves intestinal colonization mediated by fimbriae. Although, both IgY and egg yolk phosvitin (PV) possess antimicrobial activity, their combined activity has not been explored. A combination of IgY specific for ETEC and metal-chelating PV may show synergistic effect in reducing the growth of ETEC by inhibiting bacterial proliferation and stipulating protection against ETEC infection. The goal of this study was to determine the effects of anti-ETEC IgY and PV on in vitro growth inhibition of ETEC strains possessing K88 and K99 fimbriae prevalent in the porcine population. Anti-K88 and -K99 IgY antibodies were obtained from egg yolks of 23-week-old Single- Comb White Leghorn hens immunized with K88 and K99 fimbriae of ETEC, respectively, with high titres sustained over 6 to 8 weeks of the immunization period. Specific IgY, PV, and PV-hydrolysate from alcalase-hydrolysis under high hydrostatic pressure (PVH-Alc-HHP) alone or in combination, were used to treat ETEC K88 and K99 cultures at optimal concentrations of 100 μg/mL, 1 mg/mL, and 1 mg/mL, respectively, for 24 h. PVH-Alc-HHP demonstrated the highest degree of hydrolysis, 38.9%. Combined use of IgY and PVH-Alc-HHP showed the highest bactericidal effect resulting in ETEC K88 and K99 growth inhibition of 2.8 and 2.67 log CFU/mL, respectively. Combined IgY-PVH effectively control ETEC, therefore holds a great potential for microbial control in veterinary pharmaceutical industry.