City rats are unlikely to be on anyone's list of favorite animals, but researching exactly how they are problematic for public health provided a unique opportunity this past summer for Gracen Gerbig, Â鶹ÊÓƵ junior majoring in Cellular and Molecular Biology. Ms. Gerbig's summer research was supported by an Undergraduate Research Fellowship award from the .
Working with Tara Smith, Ph.D., professor of Public Health, Ms. Gerbig studied antibiotic resistance of the bacteria Staphylococcus aureus isolated from rats in Boston. Her work not only provides important information about these potentially dangerous pests from the environment, but also gave her the experience needed to solidify her long-term career goals in microbiology.
Strains of infectious bacteria that are not affected by an antibiotic represent a major medical challenge and can be life-threatening. The frequency of infections by , making it a high priority for researchers to understand their source. Ms. Gerbig's research addressed the question: Could rats be a source of antibiotic-resistant strains of Staphylococcus aureus?
And the results? Maybe a new reason to steer clear of wild rats. To answer their question, Ms. Gerbig ran a battery of tests on Staphylococcus aureus strains that collaborators had isolated from rats in Boston. All of the strains examined were resistant to at least one antibiotic (penicillin). Perhaps more concerning, one strain was resistant to four different antibiotics, and qualified as the dreaded "methicillin-resistant Staphylococcus aureus" or MRSA.
According to Ms. Gerbig, "Wild animals are carriers of Staphylococcus aureus, but there have been few studies of rodents in North America carrying S. aureus. Rodents have the potential to transmit disease to humans; Staphylococcal infections, including MRSA, are not out of the question."
Ms. Gerbig and Dr. Smith are also examining genetic sequences of the Staphylococcus aureus strains to determine mechanisms behind their antibiotic resistance, as well as their relatedness. The team plans to continue this work with whole genome sequencing to get more detailed genetic information and determine whether any of the isolates are related to those that have already been found infecting humans.
Although Ms. Gerbig had known for a long time that she was interested in microbiology and public health, the research fellowship provided the opportunity to find out what microbiology research is really like. She also attended the "Summer Undergraduate Research Experience" (SURE) program events, which provides similar experiences to undergraduates with funding from Â鶹ÊÓƵ's Office of Research. Ms. Gerbig is looking forward to presenting her research at the upcoming American Society for Microbiology national conference, and has already presented her research findings at a recent meeting of Â鶹ÊÓƵ’s Environmental Science and Design Research Initiative, which brings together faculty from across the Â鶹ÊÓƵ system who are working in both natural and built systems.
"I did not know how to get my foot in the door or begin a research project," Ms. Gerbig says. "The fellowship and the opportunity to work in Dr. Smith’s lab has allowed me to cultivate and practice my basic laboratory skills, and the project we worked on has further propelled my interest in infectious disease and epidemiology. I am confident in my decision to pursue microbiology as a profession—I love microbes! I was excited to use new equipment and practice my streaking skills, as well as learn computer software for analyzing DNA sequences. As a result, from this research, I learned that the current era of microbiology research is very much based in studying molecular genomics. Studying the genetic material of microorganisms will lead us to make new discoveries and determine which strains of bacteria are causing disease."