Laura Marie McFarland



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Listeria monocytogenes is a Gram-positive facultative intracellular pathogen, responsible for the foodborne illness listeriosis. During the infection process, L. monocytogenes is commonly exposed to propionate, a short chain fatty acid found in our gut and used as a food preservative. Although propionate is known to exhibit antimicrobial and anti-inflammatory properties, its role in L. monocytogenes pathogenesis is not clear. Therefore, I seek to further establish the effect of L. monocytogenes propionate exposure on subsequent infection. RAW264.7 macrophages infected with L. monocytogenes strain 10403s were used to assess intracellular growth. Plaque assays were performed with L fibroblasts to determine long-term impact of propionate exposure. Anaerobic L. monocytogenes pretreated with propionate was exhibited a significant increase in intracellular growth compare to untreated anaerobic L. monocytogenes. Furthermore, plaque sizes of propionate-treated anaerobic L. monocytogenes were significantly larger than plaque sizes from untreated L. monocytogenes. However, propionate pretreatment of aerobic L. monocytogenes exhibited no effect on subsequent intracellular growth or spread. These results indicate that propionate exposure of anaerobic L. monocytogenes prior to infection has a long-lasting impact on enhancing subsequent intracellular infection and cell-to-cell spread.

Publication Date


Project Designation

Graduate Research

Primary Advisor

Yvonne Y. Sun

Primary Advisor's Department



Stander Symposium project, College of Arts and Sciences

United Nations Sustainable Development Goals

Good Health and Well-Being

Pretreating Anaerobic Listeria monocytogenes with Propionate Enhances Subsequent Intracellular Infection