Phillip Brown

Listeria monocytogenes is a foodborne pathogen and the causative agent of listeriosis. L. monocytogenes has the ability to grow at a wide range of temperatures including 4°C. This along with its ability to create biofilms allows it to persist in food processing plants. Bacteriaphage are used as a biocontrol tool for L. monocytogenes in processing plants but phage resistance is an important consideration. A panel of L. monocytogenes isolates from processing plants were whole genome sequenced and tested for phage resistance against Listeria genus-specific phages. Closely related isolates of the same sequence type (ST) but different phage resistance profiles were compared for SNP mutations in genes found to cause phage resistance in lab-created mutants. Results of three STs showed that these SNPs created in a lab can also occur naturally but three other STs showed no mutations in these genes indicating novel phage resistance mechanisms.