Growth Inhibition of Escherichia coli 987P by Neutralizing IgY Antibodies

Abstract

Egg yolk antibodies, called IgY, were isolated from the egg yolks of chickens immunized with enterotoxigenic Escherichia coli (ETEC) 987P. Specific binding activity of IgY against ETEC 987P was found. Whole cell titers remained relatively high during the immunization period (up to 19 weeks). The IgY antibodies cross-reacted with other members of Enterobacteriaceae, Escherichia coli O157:H7, Salmonella enteritidis, and S. typhimurium by 28.3%, 21.1% and 19.7%, respectively. Specific IgY with a concentration higher than 0.54 mg/ml was found to inhibit the growth of ETEC 987P in a liquid medium. The difference in bacterial growth between the specific and the non-specific IgY was 6.1 log CFU/ml after 8 hr incubation. The specific binding activity of IgY to bacteria was further evaluated by immunofluorescence and immunoelectron microscopy, showing the binding of specific IgY to the bacterial surface. The immunoelectron microscopic observation revealed structural alterations on the bacterial surface bound by specific IgY. This proves that specific binding activity of IgY against ETEC 987P whole cells resulted in growth inhibition of effect ETEC 987P in vitro.

The In Vitro and In Vivo Efficacy of Hen IgY Against Vibrio parahaemolyticus and Vibrio vulnificus

“…The prepared specific IgY powder showed a significant antibacterial activity on the growth of V. parahaemolyticus and V. vulnificus. The dose-dependent pattern of the antibacterial effect observed in this study is supported by similar findings on other pathogenic bacteria such as E. coli [38,39,42], Salmonella spp. [7,39] Staphylococcus aureus [15], and Streptococcus mitis [28].…”

“…The concentrations of protein and total IgY were not influenced by the immunization schedule, but rather by the isolation process, which may have resulted in minor differences from one isolation batch to another. These analogous findings of similar concentrations of protein and total IgY in control and experimental animals throughout the immunization period have also been reported [23,38,39]. Irrespective of the constant concentrations of protein and total IgY, specific IgY in the same WSF increased with the increase in immunization period to day 49, where the peak was reached and maintained constant.…”

“…The inhibitory activity of the produced chicken IgY on the growth of the same strains of V. parahaemolyticus / V. vulnificus in liquid medium was performed according to a method reported [38]. Bacteria were grown in APW at 37 o C, 150 rpm for 18 h, and the optical density at 600 nm using UV spectrophotometer (UV-1601, SHIMADZU Corporation, Kyoto, Japan) was adjusted to 0.07 and 0.20 for V. parahaemolyticus and V. vulnificus, respectively, which corresponded to 1.0 × 10 6 CFU/ml.…”

“…IgY as a natural and food-grade antimicrobial compound can be applied in the food industry to replace chemical preservatives to prevent foodborne infections and enterotoxicity, thus improving food safety. Several studies successfully elucidated the effect of chicken IgY on the growth of various food pathogens such as Salmonella [7,23], Escherichia coli [42,27,38], Escherichia coli O157:H7 [39], vegetative and spore forms of Clostridium perfringens [31], and Staphylococcus aureus [15]. However, the in vitro and in vivo effects of IgY on Vibrio species originating from an estuarine environment have not been addressed.…”

Consumption of Water-Soluble Egg Yolk Extract on Growth Rate, Changes in Blood Cholesterol Levels, and Immune Modulation in BALB/c Mice

“…In addition, chicken egg yolk has been used as an inexpensive and effective source of immunoglobulin Y (IgY) for the treatment of various bacterial (Sunwoo et al, 2010) and viral (Wallach et al, 2011) infections in animals.…”