Survival of Escherichia coli, Enterococci and Campylobacter jejuni in Canada Goose Faeces on Pasture

Freshly excreted Canada goose faeces pose a public health risk as they contain pathogenic microorganisms. Accordingly, a study was carried out on the growth and survival of resident indicator bacteria (enterococci and Escherichia coli) and inoculated Campylobacter jejuni in freshly excreted faeces over summer and winter. Canada goose faeces were collected, mixed thoroughly and inoculated with 108 g-1C.jejuni. The faeces were mixed again before making the Canada goose dropping. The simulated goose droppings (N = 70) were placed on pasture, and the concentrations of E.coli, enterococci and the pathogen, C.jejuni, were monitored. In summer only, the molecular marker of E.coli LacZ and the avian-associated bacteria E2 was also monitored. Results of the survival study indicated that significant growth of enterococci and E.coli occurred in summer, before concentrations decreased to less than 15% of the original concentration (day 77) for enterococci and 0.01% for E.coli. LacZ followed a similar pattern to E.coli, while the E2 marker dropped to below 0.1% of the original concentration within 4 days. In winter, enterococci grew slightly, while no growth of E.coli occurred. In both summer and winter, C.jejuni was rapidly inactivated. This research highlights the ability of bacterial indicators to replicate and survive in the environment when harboured by avian faeces, and the limited risk aged Canada goose faeces pose as an environmental source of Campylobacter spp.