A Review of the Ecology, Genomics, and Stress Response of Listeria innocua and Listeria monocytogenes

Abstract

Listeria monocytogenes is a Gram-positive foodborne pathogen responsible for a severe disease occurring in immuno-compromised populations. Foodborne illness caused by L. monocytogenes is a serious public health concern because of the high associated mortality. Study of the closely related, but nonpathogenic Listeria innocua has accounted for a better understanding of the behavior of L. monocytogenes in environments beyond the laboratory. Traditionally, the ecological co-habitation, genomic synteny, and physiological similarity of the two species have supported use of L. innocua for predicting the behavior of L. monocytogenes in farm and food processing environments. However, a careful review of the current literature indicates that in a given situation it may not be prudent to use L. innocua as a surrogate for L. monocytogenes without prior confirmation of their similar phenotypes, as an increasing number of studies have arisen demonstrating differences in L. monocytogenes and L. innocua stress response, and furthermore, there are differences among the L. monocytogenes subgroups. Future research should take into consideration that multiple surrogates might be required to accurately model even a single condition depending on the L. monocytogenes subgroup of interest.

Keywords:

• Listeria
• surrogate
• stress response

ACKNOWLEDGEMENTS

Work on this review was supported by several sources: AMI grant awarded to P.G. Crandall and S.C. Ricke; USDA Food Safety Consortium grants awarded to S.C. Ricke and M.G. Johnson; and USDA/CSREES NRI grant awarded to S.R. Milillo (No. 2008-35201-04637).

Current Address for Eric C. Friedly, Land O’ Frost, Inc., 911 Hasting Ave., Searcy, AR 72143

Current Address for Joshua C. Saldivar, The Integrated Biomedical Science Graduate Program, The Ohio State University, College of Medicine, Columbus, OH 43210