The University of Georgia College of Veterinary Medicine

eorgia Veterinary Scholars Program

GVSP Summer 2007 Scholars

Georgia Veterinary Scholar	Faculty Mentor

Andrea Puckett University of Georgia Class of 2010	Dr. Mary Alice Smith

Effectiveness of Internalin A peptide in Prevention of Listeria monocytogenes Infection in Guinea Pigs

A.M. Puckett,1 D. Williams,2 E. A. Irvin,2 R. B. Raybourne,4 and M. A. Smith,2,3
College of Veterinary Medicine,1 Department of Environmental Health Science,2 Center for Food Safety,3 Center for Food Safety and Applied Nutrition,4
University of Georgia, Athens, GA 30602,1,2 University of Georgia, Griffin, GA 30223,3 U.S. Food and Drug Administration, Laurel, MD 20708 4

Listeria monocytogenes, when consumed by pregnant women in contaminated food, may result in abortion, stillbirth or neonatal illness. Listeriosis can also result in stillbirths in animals such as cows and sheep. The objective of this study was to determine if a synthetic peptide, aimed at preventing L. monocytogenes invasion of intestinal cells by blocking the surface protein, internalin A, prevented infection in non-pregnant guinea pigs as well as fetal infection and stillbirths in pregnant guinea pigs. Pregnant guinea pigs were treated on either gestation day 35 or 36. Animals were placed in three treatment groups: Group A) In1a peptide (100µg/ml) was administered orally, Group B) was administered the same dose of oral peptide followed by oral administration of 10 8 L. monocytogenes CFU/ml one hour later, Group C) 100µg/ml In1a peptide and 10 8 L. monocytogenes CFU/ml were pre-incubated for one hour and then administered orally, Group D) the control group, received the vehicle sterilized whipping cream. Listeria species were determined by plating enriched maternal and fetal tissues as well as maternal fecal samples on selective media. L. monocytogenes was confirmed using a chromogenic substrate test. Preincubating L. monocytogenes with In1a peptide did not prevent L. monocytogenes invasion of the maternal and fetal tissues. L. monocytogenes was isolated from 100% of the maternal livers and spleens, 86% of the placentas, 58% of fetal livers, and 33% of fetal brains. Of the guinea pigs that were exposed to L. monoctyogenes 1 hour following the peptide (B), L. monocytogenes was isolated from maternal liver and spleen. Interestingly, L. monocytogenes could not be cultured from the placentas or fetuses of this group. Current data suggests that when administered to pregnant guinea pigs prior to L. monocytogenes exposure, In1a peptide may reduce the occurrence of fetal infection and stillbirths.