URI College of Pharmacy researcher harvests natural viruses to seek treatment for multidrug-resistant bacteria

‘Rhody Phage Cocktail’ aims to help control ‘superbugs’

Dawn Bergantino

URI College of Pharmacy Assistant Professor Callan
Bleik displays a phage plaque spot assay demonstrating
 bacteriophage activity against a methicillin-resistant
Staphylococcus aureus (MRSA) infection.

The discovery of antibiotics transformed modern medicine, turning once-deadly infections into treatable conditions and saving millions of lives. 

But decades of overuse and misuse have accelerated the rise of antibiotic resistance, allowing certain bacteria to evolve into dangerous “superbugs” that evade even the most powerful drugs. 

As multidrug-resistant infections become increasingly difficult to treat, researchers are urgently seeking new strategies to stay ahead of these evolving pathogens.

In the University of Rhode Island College of Pharmacy, Assistant Professor Callan Bleick is leading one such effort. Bleick’s research focuses on improving treatment for drug-resistant bacterial infections, particularly those caused by methicillin-resistant Staphylococcus aureus (MRSA), one of the most prevalent and challenging superbugs in hospitals and healthcare settings.

“What motivates me most as a scientist is the growing public health threat of antibiotic resistance and the increasingly limited treatment options for patients with persistent, recurrent infections,” Bleick said. “I am particularly interested in how novel antimicrobial agents interact with existing antibiotics and behave during active infection.”

Bleick’s work centers on understanding how bacteria adapt during treatment and how combining antibiotics with emerging therapies—such as antimicrobial peptides, bacteriophages, and natural products derived from the environment and the human body—can improve infection control and reduce resistance.

A central focus of her laboratory is the study of bacteriophages, which are bacterial viruses that naturally infect and destroy specific bacteria. Bleick and her team have collected phages from soil and water sources across Rhode Island and the greater New England region, working to identify strains that effectively target MRSA. The goal is to develop a customized “Rhody Phage Cocktail,” a carefully selected combination of phages paired with antibiotics to enhance treatment effectiveness and durability.

“I am driven by the question of why today’s treatments often fail to clear drug-resistant infections and what we can do to make them work better,” Bleick said. “Although phages are increasingly used in compassionate-use cases, there is still limited guidance on how to optimally combine them with antibiotics. By studying the dynamics of these therapies, we aim to generate data that enable more effective treatment strategies with improved success rates, reduced resistance, fewer side effects, and less infection recurrence.”

Bleick has been building this research program for five years, beginning as a Doctor of Pharmacy student at URI and continuing through her postdoctoral training before launching her independent lab. Today, her research team includes undergraduate and graduate students who help design experiments and analyze data.

“Training the next generation of scientists while advancing solutions to urgent public health threats is one of the most meaningful and motivating parts of this work for me,” Bleick said.