Submitted to: Manual of Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 8, 2002
Publication Date: September 10, 2002
Citation: Parker, C., Harmon, B.G., Guard, J.Y. 2002. MITIGATION OF AVIAN REPRODUCTIVE TRACT FUNCTION BY SALMONELLA ENTERITIDIS PRODUCING HIGH-MILECULAR-MASS LIPOPPOLYSACCHARIDE. Manual of Environmental Microbiology. 4:538-545. Interpretive Summary: It is difficult for farmers to identify chickens that have acquired recent infection with Salmonella enteritidis and that are at risk for producing contaminated eggs, which is an important public health threat in the United States and other countries. The research presented here suggests that the unique molecular biology of Salmonella enteritidis helps protect the health of the chicken without stopping egg contamination. This research further suggests that the only clinical sign in flocks that might be useful as an indicator of early active infection is a subtle change in egg shell quality that occurs in response to the bacteria colonizing the hen's reproductive tract. Further research is warranted to see if high throughput methods for computerized analysis of shell quality can be developed that might detect clusters of contaminated eggs before they ever make it to market.
Technical Abstract: Hens were infected with a wild-type Salmonella enteritidis and its wzz mutant, which lacked the ability to make high-molecular-mass lipopolysaccharide, in six experiments paired by dosage and by route of exposure. Hens underwent involution of the reproductive tract when injected subcutaneously with 108 CFUof the wild-type strain, but not when injected with the wzz mutant. Infection with the wzz mutant produced more contaminated eggs and heterophilic granulomas in developing ova (yolks) than did wild-type. The mutant decreased shell quality more often than did wild-type, regardless of dosage or route of infection. These results suggest that egg-contaminating Salmonella enteritidis that produces high-molecular-mass lipopolysaccharide mitigates signs of illness in poultry, perhaps by altering the response of the avian reproductive tract to infection, without altering the incidence of egg contamination following bacteremia. Further research is thus warranted to determine whether analyses of shell quality might aid identification of flocks at risk for producing contaminated eggs.