6 Different antibiotics and how they work
Posted on 7 November 2018
When penicillin was discovered in the late 1920s, it sparked the modern age of antibiotic (or antimicrobial) treatments. This saved millions of people from disease or death resulting from bacterial infections. Dr Amima Sundas, a specialist physician at Mediclinic Newcastle, explains how antibiotics work, and how many different kinds there are.
“There is a vast range of antibiotics,” says Dr Sundas. “There are antibiotics that are used to treat respiratory infections, others that treat skin infections, stomach infections and urinary tract infections.” The total number of antibiotics currently available to medical professionals is just over 100, but that number goes up as new antibiotics are discovered or developed, and down as harmful bacteria build up resistance to the existing antibiotics.
Dr Sundas says that antibiotics are categorised as first-line, second-line and third-line treatments, based on the order that prescribing doctors tend to use them to treat a particular illness or condition. “A first-line penicillin treatment like Augmentin, for example, is prescribed very widely for infections,” she explains.
Another way to categorise antibiotics is based on what they do – or, in other words, on the cellular component or system they affect, and on whether they kill the bacterial cells (these are known as bactericidal drugs) or simply prevent those cells from growing (bacteriostatic drugs).
To limit the risk of antibacterial resistance, Dr Sundas says that doctors have to take special care when they choose which antibiotics to prescribe to a particular patient with a particular infection in a particular community. “It’s a very delicate process,” she says. “As a doctor, one would have to look at the patterns in the local geography, and determine which organisms are responsive to which antibiotics. One would then base one’s choice of antibiotic on those factors.”