Detection and identification of adhesins involved in adhesion of Campylobacter jejuni to chicken skin

Abstract

Campylobacter jejuni is the leading cause of bacterial food poisoning worldwide. Chickens are considered to be one of the major reservoirs of Campylobacter infection in humans due to colonization of their intestinal tract. When the chickens are slaughtered and processed, the entire skin of the carcass becomes contaminated with campylobacters. We observed that the number of C. jejuni attached to chicken skin was reduced significantly after treatment of the skin with sodium hydroxide followed by washing with PBS, implying that adhesion factors involved in binding to C. jejuni may exist on skin. Such potential binding-related proteins present in alkaline extracts of the skin surface were detected by a two-dimensional overlay assay and identified by liquid chromatography mass spectrometry (LC-MS). Chicken serum albumin (CSA) was identified as a major protein in these alkaline extracts and confirmed by ELISA to bind specifically to C. jejuni. Moreover, using the same approach, flagellar hook protein E (FlgE) and major outer membrane protein (MOMP) in C. jejuni were identified as bacterial adhesins that bound to the CSA. The ability to bind CSA was also confirmed using recombinant FlgE and MOMP of C. jejuni expressed in Escherichia coli. The present findings suggest that adhesins expressed on C. jejuni cells may bind specifically via proteins present on the skin, as well as by physical attachment.