Grace Musai
Pronouns: she/her
Research Mentor(s): Evan Snitkin
Co-Presenter:
Research Mentor School/College/Department: Microbiology and Immunology / Medicine
Presentation Date: April 20
Presentation Type: Oral5
Session: Session 5 – 3:40pm – 4:30 pm
Room: Breakout Room 2
Authors: Grace Musai, Evan Snitkin, Ashley Miihlbach
Presenter: 1
Abstract
Infections caused by multidrug resistant bacteria are a serious threat to public health. Colistin is a last line antibiotic to treat multidrug resistant Klebsiella infections, which are often found in hospitalized patients. A study that my research mentor, Evan Snitkin, and his colleagues completed examines the evolution of colistin resistance among the ST258 lineage of carbapenem-resistant Klebsiella pneumoniae in 21 U.S. hospitals over the course of a year. They found that certain colistin resistant strains of Klebsiella spread between patients, while others did not. Existing research on antibiotic-resistant bacteria strains tells us that bacteria that are resistant to antibiotics typically have a reduced fitness, or the reduced ability of the bacteria to replicate and grow in a competitive environment, when compared to their susceptible counterparts. In the first step for this project, we will compare the fitness cost of a bacterial isolate that is a susceptible revertant, bacteria that have at least one resistance mutation and are susceptible to antibiotics, and an isolate from the resistance clusters, a group of resistant isolates that contain the same resistance variant. The initial growth rate of the different strains will be measured by computing the concentration of bacterial colonies over a certain period of time. We hypothesize that we will see more growth in the susceptible revertant bacteria than in the resistance cluster bacteria because we think that having resistance mutations will have some kind of cost to the bacteria’s growth and replication abilities. This result would support the claim that there is a fitness cost associated with colistin resistance. Whether the results indicate susceptible revertants have the same or different fitness as resistance clusters, the next experiment would be to test the isolates under different conditions since fitness can vary in the presence or absence of an antibiotic like colistin.
