Antimicrobial resistance remains one of the greatest threats facing healthcare, and pharmacists need new therapies to improve patient outcomes.
While rarely used in practice, bacteriophages are emerging as a viable investigational therapy to treat highly resistant bacterial infections.
A session at the ASHP 2025 Midyear Clinical Meeting & Exhibition, Bacteriophages for the Assist: Adjuncts to Antibiotics for Multidrug-Resistant Bacterial Infections, will make the case for learning how to incorporate bacteriophages into antimicrobial stewardship programs.
“People are getting sicker, and cases are getting more complex. We need more therapeutic options to help them,” said Bryan P. White, infectious diseases clinical pharmacist at the University of Oklahoma Medical Center.
White and his Midyear co-presenters spoke with ASHP’s News Center in advance of their Dec. 8 session.
The promise of phages
Bacteriophages, or phages for short, are viruses that infect and reproduce only in bacterial cells, causing them to burst. Phages are abundant in the natural environment, including water, soil, and sewage.
Because they combat bacterial infections in different ways, phages and antimicrobials can create a synergistic effect when used together or in succession.
These traits make phages a promising option for fighting infections that would otherwise be considered untreatable. What’s more, phages are highly targeted to specific strains of bacteria, so they typically won’t harm other cells or healthy bacteria in the body.
“One of the positives of using phages is that there’s not the collateral damage that you see with a lot of antibiotics,” explained Amer El Ghali, an assistant professor with the University of New Mexico College of Pharmacy.
Phages in practice
White and his colleagues plan to present several scenarios for when bacteriophages might be most successful in clinical pharmacy. So far, phages have been proven to be most effective for difficult-to-treat gram-positive infections, including methicillin-resistant Staphylococcus aureus. But they remain an experimental, last-line therapy.
“There are some really elegant case reports of patients that have tried everything else for a gram-positive infection, but it keeps coming back,” said Ashlan J. Kunz Coyne, assistant professor at the University of Kentucky College of Pharmacy. “At that point, you’re out of antibiotic options, so you’re thinking phage. And we’re still working through what that looks like in practice.”
Phages are also highly effective at treating multi-drug resistant gram-negative infections. Viruses have a natural ability to genetically evolve with the bacteria they bind to — something antimicrobials can’t do.
“Sometimes a phage actually is more attuned to a bacterium that has resistance mechanisms,” El Ghali said. “Some studies show that they also reduce virulence, which helps alleviate some of the symptomatology, morbidity, and mortality for the patient.”
Safety, logistical hurdles
Several barriers stand in the way of widespread clinical use of phage therapy. The presenters hope sessions like theirs will help generate more awareness and demand — and that research, education, and clinical practice will follow.
Patient safety is first and foremost, as there have been reports of immune reactions to phages. Potential phase resistance is a concern, as is making sure therapeutic phages are free of the toxins used to produce them in a lab.
More clinical trials are needed to substantiate the safety and efficacy of phage therapy before it can be approved for standardized use in the United States, the presenters noted. Acceptance of phages will require a mindset shift, particularly in the wake of the coronavirus pandemic. As El Ghali put it: “People worry about putting viruses in their body.”
Procurement is yet another challenge. As a biological agent, phages are not manufactured or regulated in the same way as traditional therapeutics. Only a few U.S. laboratories are equipped to test bacterial isolates and to identify and produce the corresponding phage treatment for a specific infection. Obtaining phage therapy can take months, so it is currently used most often for patients with chronic conditions such as skin, bone, and joint infections.
The speakers will provide Midyear attendees with resources for acquiring bacteriophages and tips to streamline the process. They encourage pharmacy leaders to incorporate phage therapy into compassionate-use approval protocols and to build relationships with qualified labs in advance.
“There are pathways to get phage, but you have to be very patient,” Kunz Coyne said. “It’s completely different from an antibiotic, where any institution could just jump into their ordering system and order what they need.”
The speakers predict bacteriophages will continue to catch on, and the urge their fellow pharmacists to stay informed, just as they would with any cutting-edge treatment.
“When you look at antimicrobial resistance, you can show chart after chart of things getting worse. . . . So to even be able to talk about another treatment option is exciting,” said White. “When you have a patient where everything is resistant, [phages] can mean hope.”
