Scientists have identified a virus which “eats” the bacteria that causes the hospital superbug Clostridium difficile (C.diff), in a breakthrough that could have major implications for the fight against antibiotic resistance.
The technique represents a viable alternative to antibiotics for the treatment of bacterial infection, using naturally occurring viruses called bacteriophages – ‘eaters of bacteria’, or phages for short.
Researchers at the University of Leicester have isolated phages that specifically target C.diff, an infection of the gut that killed 1,646 in the UK last year. In lab tests, funded by the Medical Research Council, the viruses were 90 per cent effective against the most dangerous strains of the bug.
The danger posed by growing resistance to antibiotics is one of the gravest health risks facing the world, doctors have warned, and alternative methods for treating bacterial infections are being urgently sought.
Dr Martha Clokie, who led the research at Leicester’s Department of Infection, Immunity and Inflammation, said that phages could have a major role to play in coming decades.
“The future impact of antibiotics is dwindling at a pace that no one anticipated, with more and more bacteria out-smarting and 'out-evolving' these miracle drugs. This has re-energised the search for new treatments,” she said.
Unlike antibiotics, phages generally only infect one strain of bacteria. This could make them particularly effective as a treatment for C.diff infections, which become dangerous when antibiotic treatments interfere with the balance of “good” bacteria in the gut.
They work by infecting bacteria cells, and replicating their DNA inside the cell. This ultimately leads to the cell bursting open and dying, with the new phages released from the dead cell and spreading to kill off other bacteria cells.
The technique was first used more than a hundred years ago but the development of effective antibiotics in the early 20th century meant it was very rarely used by British doctors – although it persisted in Eastern Europe and is still common in some countries including Georgia and Poland.
“As bacterial diseases become more problematic and we run out of antibiotic options to treat them we’ve seen a resurgence of interest in this field,” Dr Clokie said.
“My Russian colleagues at the University of Leicester were all given phages when they were kids for various problems, but in the UK their use has been completely superseded by antibiotics,” she said.
Increasing antibiotic resistance has been highlighted by doctors as one of the major threats facing the world. England’s chief medical officer Dame Sally Davies warned earlier this year that routine operations could become deadly in 20 years’ time if we lost the ability to fight infections, and said that the UK should rank the threat alongside terrorism.
Dr Clokie’s work marks the first time that phages have been used against C.diff bacteria. The next stage of development will see a mixture of the most effective phages used in phase I trials in people, funded by the pharmaceutical company AmpliPhi.
Dr Clokie said that it was very likely the technique would be safe in humans, because the viruses used had been specifically identified to only target the bacteria that cause C.diff.
Dr Des Walsh, head of Infections and Immunity at the Medical Research Council, which funded Dr Clokie’s lab tests, said: “Antibacterial resistance is a major and growing threat to health globally.
New treatments and therapies are sorely needed. This study by Dr Clokie examines a new way to kill bacteria to circumvent resistance formation. She has established an impressive collection of ‘phage’ viruses and has developed strong partnerships to translate her research into potential new treatments for Clostridium difficile infection – an excellent example of moving basic experimental MRC funded research along the development pipeline.“