Prevalence and Characterization of Campylobacter jejuni Isolated from Pasture Flock Poultry

Abstract

The growing interest in organic and natural foods warrants a greater need for information on the food safety of these products. In this study, samples were taken from 2 pasture flock farms (N = 178; feed, water, drag swabs, and insect traps), pasture flock retail carcasses (N = 48) and 1 pasture flock processing facility (N = 16) over a period of 8 mo. A total of 105 Campylobacter isolates were obtained from 53 (30%), 36 (75%), and 16 (100%) samples from the farms, retail carcasses, and processing facility, respectively. Of the 105 isolates collected, 65 were C. jejuni, 31 were C. coli, and 9 were other Campylobacter spp. Using PCR, the C. jejuni isolates were further analyzed for virulence genes involved in colonization and survival (flaA, flaC, cadF, dnaJ, racR, cbrR), invasion (virB11, ciaB, pldA), protection against harsh conditions (sodB, htrA, clpA), toxin production (cdtA, cdtB, cdtC), siderophore transport (ceuE), and ganglioside mimicry (wlaN). In addition, the short variable region of the flaA locus (flaA SVR) was sequenced to determine the genetic diversity of the C. jejuni isolates. The flaA SVR diversity indices increased along the farm to carcass continuum. PCR-based analysis indicated a low prevalence of 5 genes involved in colonization (dnaJ, ciaB, pldA, racR, virB11). The results of this survey indicate that the prevalence of Campylobacter on organic retail carcasses is similar to prevalence reports of Campylobacter on conventional retail carcasses. However, the genetic diversity of the flaA SVR genotypes increased along the farm to carcass continuum that contrasted with conventional poultry studies. Campylobacter jejuni is a leading cause of foodborne illness with poultry and poultry products being leading sources of infection. Free-range and pasture flock chickens are becoming more popular; however, there is an inherent biosecurity risk that can increase the prevalence of foodborne pathogens in these flocks. This study aimed to determine sources and characterize C. jejuni isolated from pasture flocks.