Survival of Campylobacter jejuni on eggshells
Abstract S5
Presenter: Ingrid Hansson (Swedish Univeristy of Agricultural Sciences)
The most common ways of acquiring campylobacteriosis are by consuming contaminated chicken products, dairy products, and water. Many animals carry Campylobacter in their intestines without showing any symptoms of disease. The intestines of poultry can be colonized with Campylobacter up to log 8 CFU/g faeces. Eggshells may be contaminated with Campylobacter after being exposed to faeces during laying, which in theory can be transmitted to humans or newly hatched chicks. There is a lack of knowledge of the risk for humans being infected with Campylobacter via contaminated eggshells, and if/how often Campylobacter can be transmitted from parent birds to newly hatched chicks via contaminated eggshells. The aim of this study was to examine if Campylobacter can survive on eggshells and if so, for how long. The results can answer the questions whether table eggs can cause campylobacteriosis in humans and if Campylobacter can be transmitted from parent birds to newly hatched chicks (if Campylobacter are present on the outside of the eggs). Eggs were artificially contaminated by dipping in broths of three different concentrations and sequence types (ST-148, ST-257 and ST-918) of C. jejuni, with or without addition of caecal contents. The eggs were stored in a refrigerator and analyzed for presence of Campylobacter after 114 days. Qualitative analyses were performed according to ISO 10272 with enrichment in Bolton broth and culture on mCCDagar. Some of the samples were also analysed by qPCR. Sequence typing was used for strain identification of cultures and reisolated Campylobacter from eggshells. After one day in the refrigerator C. jejuni were detected by qPCR from 21 (70%) out of 30 eggs whereas after enrichment and culture on mCCDA C. jejuni were isolated from 16 (18%) out of 90 eggs. After four and seven days C. jejuni were not isolated from any of the eggs after enrichment and culture on mCCDA. However, one of sixty egg dipped in ST-918, C. jejuni were detected after enrichment and culture on mCCDA after 10 days of storage in the refrigerator. Based on the results of this study, it cannot be excluded that there is a risk for the consumer of becoming infected with Campylobacter via eggs, though the risk is small as there are several criteria that need to be met for this to be possible. However, the risk is bigger for staff at packing plants and on farms who handle eggs shortly after they have been laid. There is also a potential risk of transmission from eggs to newly hatched chicks via eggshells if storage is short and optimal condition for Campylobacter are achieved.
About the presenter
Main focus in my research has been identification of sources and risk factors for colonisation of Campylobacter spp. at farm level and at slaughter, in purpose to reduce the occurrence of Campylobacter in broilers. I have previously worked as scientific officer at the EUs Reference Laboratory (EURL) for Campylobacter at the National Veterinary Institute, Uppsala, Sweden. Nowdays, I am a senior lecturer of Bacteriology in Veterinary Medicine, at the Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences.
Presenting in Speaking session 4 - Survival and application