Meredith Irsfeld

Position: Research Assistant, MICR 202L Teaching Assistant
Lab: Van Es 108
Office: Van Es 193
Program: Microbiology MS
Advisor: Dr. Pruess

Graduate Student Profile

Education:
BS in Microbiology, with a Minor in Chemistry from North Dakota State University

Research Focus:
Our lab’s long term goal is to expand our knowledge of gene regulation and expression involved in the different stages of bacterial biofilm formation. Bacterial biofilms are complex spatially structured microcolonies of bacteria that can attach to any surface or each other. Unfortunately, they are commonly associated with bacterial infections that involve biofilm formation on implants, heart valve, joint prostheses, and urinary catheters. Due to their complex structure and encapsulation of polymeric substance, bacterial biofilms are difficult to treat. A better understanding of gene regulation involved in the stages of biofilm formation could help to identify target sites for safe, effective treatment options.

Previous research has focused on different genetic characteristics involved in biofilm formation of nonpathogenic Escherichia coli K-12 strains. These characteristics have been shown to affect the amount of biofilm production and alter the three dimensional structures of biofilms. Another project screened 190 chemicals, which were tested for their effect on E. coli O157:H7 growth, planktonic bacterial counts, and biofilm amounts. This is a strain of E. coli commonly associated with food poisoning. Among these chemicals, phenylethylamine (PEA) had the greatest inhibitory effect. This effect of PEA was also seen when pieces of beef were treated with PEA prior to inoculation with E. coli O157:H7.

My research project has been a combination of investigating genetic characteristics involved in biofilm formation of nonpathogenic E. coli K-12 mutants and the effect it has on bacterial biofilm stability. We test biofilm stability using an automated water jetting instrument that has previously been used to quantify adhesion strength of marine organisms on specific coatings. We’ve found that genes directly involved in determining cell surface structures of bacteria in the biofilm affect stability. Whereas, metabolism genes affect biofilm formation, but have less of an effect on stability. The second part of my project focuses on testing the effect of a range of PEA concentration on a non-pathogenic E. coli K-12 strain. PEA has been shown to have inhibitory effects on biofilm amounts, planktonic growth, and planktonic cell counts of nonpathogenic E. coli K-12. We are continuing to investigate the effect of PEA on biofilm amounts and planktonic growth of pathogenic strains associated with the clinical infections mentioned above. I’ll be focused on testing a pathogenic strain of Staphlococcus aureus, Pseudomonas aeruginosa, and two strains of Uropathogenic E. coli (UPEC).

In the future, I am interested in being involved in research that works to develop applied materials and treatment options to help prevent biofilm-associated bacterial infections. This is a passion of mine shaped by firsthand experiences with patients inflicted by these biofilm-associated bacterial infections, when I was working in a dialysis clinic.

Selected Publications:

  1. Irsfeld ML, Prüß BM, & Stafslien SJ (2014) Screening the mechanical stability of Escherichia coli biofilms through exposure to external, hydrodynamic shear forces. J. Basic Microbiol. 54:1-8.
  2. Irsfeld ML, Spadafore M, & Prüß BM (2013) ß-phenylethylamine, a small molecule with a large impact. WebMedCentral Biochemistry. WMC004409.
Notable Achievements:
  • Awarded an Honorable Mention for a research proposal submitted to the National Science Foundation (NSF) Graduate Research Fellowship Program (2014)
  • 1st place in the undergraduate student oral presentation competition at the Meeting of the North Central Branch of the American Society for Microbiology, Fargo, ND (2012)
  • 1st place in the undergraduate student poster competition of MICR480 Bacterial Physiology (2012)

Department and Community Involvement:

  • VMS Graduate Student Association Vice President
  • 35th Annual Expanding Your Horizons Conference Workshop Leader
  • Organizer/Participant of the VMS GSA’s presentation at Shanley High School sharing with the students, research projects in the department

Contact Information:
Email: meredith.irsfeld.1@my.ndsu.edu