Using Viruses to Kill Bacteria

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The researchers further tested the bacteriophages' effectiveness, removing the treated sutures and placing them directly into a culture dish full of MRSA bacteria, obtained from patients in three different U.K. hospitals. They found that the virus remained active for up to three weeks, effectively killing off 96 percent of bacteria in culture.

Spencer says that, while bacteriophages will not completely replace antibiotics in fighting infection, these viruses have important advantages. "Antibiotics are broad-spectrum, and for certain bacterial strains, it's easier to use bacteriophages if you know exactly which bacterium is causing the infection," she says. "[With bacteriophages,] you can target one strain, and it wouldn't affect any other bacteria that may be protecting cells."

Synthetic biologist James Collins recently engineered viruses that kill off colonies of bacteria, called biofilms. Collins, a professor of biomedical engineering at Boston University, says that Spencer's technique clears many hurdles that have stymied bacteriophage use in the past. "It can be a surface-mounted bacteriophage, so instead of worrying about issues of ingesting a virus, by limiting application to the surface, they get around that concern," he says. "I suspect there might be interest in the Defense Department to use this early to treat infections in soldiers on the battlefield."

The Scottish team also hopes to incorporate microscopic beads of bacteriophages into sprays and creams, which, once dry, can remain active against bacterial infection for prolonged periods of time. The researchers are also exploring other methods of binding bacteriophages onto polymers, including a process known as corona discharge, which is commonly used to imprint ink onto plastic supermarket bags. The method involves a burst of high-voltage electricity, which acts to break up a polymer surface. Spencer says that this technique, patented by the University of Strathclyde, may improve the binding between polymer beads and bacteriophages.

In addition to therapeutic applications, bacteriophages may be useful in detecting bacterial infection, and the Scottish team has plans to investigate bacteriophages' diagnostic potential.

Spencer presented the group's findings at a recent meeting of the Society for General Microbiology, and since then, she has received queries from hospitals and pharmaceutical companies that have expressed interest in an antibiotic alternative. Currently, the team is in negotiations with Gangagen, a Canada-based biotechnology company that works on bacteriophage-based therapies.