The idea that patients should always complete a course of antibiotics has again been challenged by academics.
A new laboratory study by the University of Exeter suggests that treatments using antibiotics should stop as soon as possible to prevent patients becoming resistant to their effects.
“In some clinical studies, resistance didn’t disappear when the antibiotic did”
The researchers found that cutting the length of the antibiotic course reduced the risk of bacteria building up resistance to the drug.
An evidence review, published last year in the British Medical Journal, reached a similar conclusion.
Experts at Brighton and Sussex Medical School found that stopping antibiotic treatment early did not encourage antibiotic resistance, while taking antibiotics for longer than necessary increased the risk of resistance.
The Exeter research, published yesterday in the journal Nature Ecology & Evolution, looked at the relationship between antibiotics and blood glucose levels.
Different people will have different blood sugar levels and that will have an impact on antibiotic resistance in their bodies, said Professor Robert Beardmore who led the study.
Sugars work as “uppers” stimulating pathways and antibiotics as “downers” inhibiting pathways, he told Nursing Times.
The research found that changes in the duration and dose of antibiotics used, together with different sugar levels could push microbial communities – groups of microorganisms – beyond a “tipping point”, creating an irreversible shift to drug resistance.
It demonstrated that resistant species could increase within the body even after an antibiotic was withdrawn, if a tipping point was unwittingly passed during treatment, the researchers said.
For decades patients being prescribed antibiotics have been instructed to complete the course.
The received wisdom was that if too few tablets were taken the bacteria would be able to mutate and become resistant. But that view is increasingly coming under fire from scientists.
Professor Beardmore said: “It’s a sensible idea that when you take an antibiotic away, resistance goes away too, but we wondered what kinds of antibiotic treatments don’t behave like that. After all, in some clinical studies, resistance didn’t disappear when the antibiotic did.”
However, the Royal College of GPs reacted cautiously to last year’s BMJ study, saying that a course of antibiotics was “not random” in its duration and had been “tailored to individual conditions”.
Meanwhile, the Exeter University study comes at a time when the National Institute for Health and Care Excellence is trying to cut the prescription of antibiotics.
Earlier this week, NICE published draft guidance stating that antibiotics should be restricted for chronic obstructive pulmonary disease.
It said that health professionals should consider the risk of antimicrobial resistance when deciding whether antibiotics were needed for treating or preventing a flare up of symptoms of COPD.