By: Cassidy Delamarter, University Communications and Marketing
With two new grants from the National Institutes of Health - totaling more than $4.4 million - University of South Florida microbiology Professor Lindsey Shaw is leading an interdisciplinary effort to stop one of the world's most dangerous bacterial pathogens.
Methicillin-resistant Staphylococcus aureus, commonly known as MRSA, is a type of staph infection that's resistant to most antibiotics. With an arsenal of toxins, it can cause infection in nearly every part of the human body. Despite decades of study, scientists still don't understand how MRSA controls toxin production during infection and its survival strategies.
"It's adapted to be really good at surviving on surfaces, like carts, shelves, desks, computers and keyboards," Shaw said. "It's just one of the ultimate human pathogens."
For Shaw, the work is personal. At 13, a hip surgery to correct a genetic deformity left him with three surgical pins, two of which became infected with Staphylococcus aureus, a sister of MRSA. What followed was five years of hospital stays and intensive antibiotic treatments.
"That experience gave me a firsthand understanding of how devastating and persistent these infections can be," Shaw said. "It's what drove me to study bacteria and, ultimately, to focus my career on understanding and defeating MRSA. This research is about saving lives."
Fall 2025 marked the first semester of Shaw's new lab. He says launching this lab has been his dream and that he can't wait to see what the students accomplish this semester.
To accelerate discovery and train the next generation of scientists, Shaw launched an undergraduate antimicrobial resistance lab, giving students hands-on opportunities to study hundreds of strains, including a new one now spreading across Florida.
That strain, dubbed the "snowbird clone," was detected thanks to the 2024 USF CREATE Award, which funded Shaw's partnership with Dr. Kami Kim, professor of medicine and director of the Division of Infectious Disease and International Medicine in the USF Health Morsani College of Medicine.
MRSA on petri dish
The CREATE Award also supported the launch of the USF Center for Antimicrobial Resistance, which uses genome sequencing to characterize new antibiotic resistant bacteria, such as the snowbird clone.
First identified in Canada about 15 years ago, the snowbird clone has since migrated south, with 36 of the 65 known cases worldwide detected in Tampa - the highest concentration anywhere. Additional cases in Jacksonville, Gainesville and Miami suggest the strain is establishing itself across Florida. The study - recently published in The Journal of Infectious Diseases - is the first to detail how this rare strain functions and to map its genetic code. The findings indicate that MRSA is expanding, evolving and becoming more genetically diverse in patient populations than previously recognized.
Emily Felton
The discovery was made by Emily Felton, who recently graduated from USF's cell and molecular biology doctoral program. She says the research helped her realize her passion to support clinicians. "As a scientist and a researcher, I want to help the clinicians and hospitals improve patient outcomes," Felton said. She plans to stay at USF as a postdoctoral researcher to continue working alongside Shaw and Kim, who plan to further analyze the snowbird clone.
"Our success reflects the value of investing in interdisciplinary teams," Kim said. "The CREATE Award allowed us to bring together expertise from microbiology, clinical medicine and genomics, which led to discoveries we never anticipated."
According to Shaw, the big question now is whether the snowbird clone will burn itself out, or dominate across the U.S. With his new NIH funding, he plans to dig deeper into MRSA's genetic strategies, with the goal of finding weaknesses that can be targeted by future treatments. Shaw's discoveries could help curb the spread of dangerous strains in Florida and beyond.
"Our work is a team effort," Shaw said. "We're bringing together students, clinicians and researchers to tackle urgent public health threats right here in our community."
