Image via iStock.
Most people believe – and have been told by health professionals – that it’s essential to finish a course of antibiotics to prevent antibiotic resistance. But this advice is not only wrong, it could actually be harmful.
The idea that you have to take all the antibiotics you’re prescribed is based on the assumption that all the bacteria causing the infection have to be killed, so the surviving minority don’t become resistant. In fact, for most otherwise healthy people, significantly reducing, but not necessarily totally eliminating, the bacteria causing the infection allows the body’s natural defences to take over and mop up the remaining few.
Some important conditions
There are some special circumstances when it’s important to kill all the bacteria – when the patient’s normal defences are damaged for any reason, for instance, or when the infection is in a site that’s relatively inaccessible to antibiotics and the white blood cells that kill bacteria. This can be in the middle of an abscess or cavity filled with pus (as in tuberculosis infection), on a foreign body, such as a prosthetic heart valve, or in dead tissue that can’t be removed (as in osteomyelitis or infection of the bone).
Obviously, stopping antibiotics before a serious infection is cured will risk a relapse. That’s what happened to Albert Alexander, the London policeman who was one of the first people to be treated with penicillin by Howard Florey in 1941.