Recovery of Salmonella enterica serovar Enteritidis from hens initially infected with serovar Kentucky.

Abstract

Salmonella enterica serovars Enteritidis and Kentucky differ greatly in epidemiology. We wanted to know if the non-pathogenic serotype Kentucky impacted the recovery of the pathogen Enteritidis from chickens. To explore this issue, 4 groups of hens were treated as follows: (i) hens were inoculated orally with Kentucky and injected intramuscularly 2 weeks later with Enteritidis, (ii) hens were contact infected with Kentucky and then with Enteritidis, (iii) hens were injected with Enteritidis only, and (iv) hens were contact infected with Enteritidis only. Hens exposed orally to serotype Kentucky received 10 exp9 CFU, and hens injected with serotype Enteritidis received 10 exp7 CFU intramuscularly. Contact infected hens were kept in rooms with deliberately infected hens. Droppings, cecal tonsils and 5 internal organs were sampled and cultured at 6, 13 and 20 days post-infection from the 4 groups. Egg production was monitored. Results suggest that non-pathogenic serotypes of Salmonella may mitigate recovery of Enteritidis from chickens exposed by contact. In summary, we show results from an initial experiment intended to investigate if multiple serotypes impact the ecology of pathogenic S. enterica on-farm.