As bacteria become more resistant to antibiotics, it will become more difficult to treat bacterial infections, leading to more severe illness, longer hospital stays and higher death rates.
As a student at Virginia Tech, Megan O’Hara had a unique opportunity to study how bacteria move across surfaces — a process known as twitching — under the mentorship of Zhaomin Yang, professor of biological sciences. This movement allows bacteria to quickly colonize new surfaces, including those of tissues and medical implants.
The findings from O’Hara’s two-year research efforts led to the surprising discovery of the key role that surface properties play in enabling or preventing this movement. The research was recently published in mSpherethe premier open access journal of the American Society for Microbiology.
Muscle twitching is made possible by small structures called type IV pili (T4P). They are part of the weaponry of certain bacteria that allows them to infect and harm people. Unlike other forms of bacterial movement, such as swimming or swarming, twitching occurs on solid or semi-solid surfaces. Vibratory motility is a form of motility associated with many bacteria that possess T4P, and some of these bacteria are antibiotic resistant.
The visualization of muscle twitching via crystal violet staining. Photo courtesy of Megan O’Hara.
“We want to work with these pathogens that have high levels of resistance to antibiotics, such as those identified by the World Health Organization, because they pose an increased risk to human health,” said O’Hara, lead author of the study. graduated in 2024 with a bachelor’s degree in microbiology.
The World Health Organization lists antibacterial resistance as a top 10 threat to global health, with an estimated 1.27 million deaths in 2019 directly attributed to drug-resistant infections worldwide. It is predicted that this number will rise to 10 million by 2050 if nothing stops this pace.
“Antibiotic research is very important and a hot area of research right now,” O’Hara said. “And one way you can achieve this is that instead of killing the bacteria, you take away their weapons and armor so that they can no longer colonize or harm our bodies. They become losers in the competition with the good bacteria that normally live in our bodies.”
The research revealed an unexpected discovery, as the researchers were able to determine that the function of T4P in motility depended on the properties of a surface. Their research found that bile salts and other detergents enhance bacterial twitching by making the surface hydrophilic rather than affecting the bacteria’s biology. In other words, by manipulating the surface properties, the functionality of the T4P can be changed.
Megan O’Hara graduated in May after double majoring in microbiology with a double degree in biomedical biological sciences and a minor in chemistry. In addition to receiving two awards from the Department of Biological Sciences, she was a Virginia Tech Presidential Scholar. Photo courtesy of Megan O’Hara.
“Learning about T4P is very important because it is what we call a critical virulence factor,” O’Hara said. “And why we call it critical is that in many species, once you remove the T4P, the bacteria can no longer cause an infection.”
O’Hara is now a first-year Ph.D. student in the biomedical sciences program at the University of California, San Diego. As a student and Virginia Tech Presidential Scholar, she received two awards from the Department of Biological Sciences, including the Buikema and Galway Undergraduate Research Award and the David Lyerly Summer Fellowship.
“I am proud of Megan’s achievements as a student at Virginia Tech,” Yang said. “She is the student of every professor’s dream, smart, driven and independent. It is extraordinary to have a student as the lead author of a primary research paper.”
The study was supported by the National Science Foundation and a pilot grant from Virginia Tech’s Center for Emerging Zoonotic and Arthropod-borne Pathogens, of which Yang is an affiliate faculty member.
