Investigation of the impact of food preservatives on avian pathogenicEscherichia coli(APEC) and their role in driving zoonotic disease

Abstract

The excessive use of antibiotics in agriculture is routinely described as a major contributor to bacterial antimicrobial resistance. Globally, antibiotics are also widely used as growth supplements in livestock. This has led to concerns regarding use of human-use antibiotics in food and food-producing animals. In more recent times organic acids such as propionic acid (PA) and formic acid (FA) have been used as alternative antimicrobials or preservatives in place of antibiotics. PA is a short chain fatty acid naturally abundant in the human and animal intestine as a breakdown product of non-digestible carbohydrates. In the human intestine it plays important roles in regulating the immune response in the human body. Recently, a study has shown that exposure of a Crohn’s Disease associated bacterial pathotype, adherent-invasive Escherichia coli(AIEC),to PA significantly altered its phenotype resulting in increased adhesion and invasion of epithelial cells and increased persistence through biofilm-formation. AIEC are both evolutionarily and phylogenetically related to avian pathogenicEscherichia coli (APEC). PA and FA use is widespread in chickens a known source of zoonotic disease. Our results indicate that virulence of some APEC strains is increased by exposure to alternative antimicrobials such as PA and FA. This included increased adhesion of APEC strain E. coli 601 to human intestinal epithelial cells after exposure to FA which could be a potential risk of zoonotic disease. Further investigation of APEC strains is currently underway in a fermentation model of the poultry gut. This approach will improve our understanding of how commonly used.