Colony characteristics of Escherichia coli.

MN Impact: Researchers Develop Models for Key Strains of L. Monocytogenes

August 27, 2019

Objective

Research will increase understanding of threats to food safety from microbial and chemical sources.

Issue

Listeria monocytogenes is a microorganism of great concern for the food industry and the cause of human foodborne disease. About 1,600 people get listeriosis each year, and about 260 die. Pregnant women and their newborns, adults aged 65 or older, and people with weakened immune systems are especially vulnerable.

What has been done

David Baumler and his collaborators set out to generate genome-scale metabolic models (GEMs) for six different strains of L. monocytogenes, and to both qualitatively and quantitatively validate these GEMs to examine the diversity of metabolic capabilities of numerous strains from the three different serovar groups most associated with foodborne outbreaks and human disease. 

Results

Following qualitative validation, 57 of the 95 carbon sources tested were present in the GEMs. Of these 57 compounds, agreement between in silico predictions and in vitro results for carbon source utilization ranged from 80.7 to 91.2 percent between strains. They then conducted nutrient utilization agreement between in silico predictions and in vitro results.

Quantitative validation showed that the L. monocytogenes GEMs could generate in silico predictions for growth rate and growth yield that were strongly and significantly (p < 0.0013 and p < 0.0015) correlated with experimental results. 

These GEMs for L. monocytogenes are comparable to published GEMs of other organisms for agreement between in silico predictions and in vitro results. Therefore, as with the other GEMs, namely those for Escherichia coli, Staphylococcus aureus, Vibrio vulnificus, and Salmonella spp., they can be used to determine new methods of growth control and disease treatment.