Antibiotic

An antibiotic is a medicine that kills or stops the growth of bacteria. It does not act on viruses, and the full course must be completed to avoid resistance. Malay: antibiotik · Chinese: 抗生素.

An antibiotic is used to treat infections caused by bacteria, such as some sore throats, wound infections and pneumonia. It works either by killing the bacteria or by stopping them from multiplying, so the body can clear the infection. Two rules always come with antibiotics in the syllabus: they have no effect on viruses, so they cannot cure a common cold or flu, and the whole course must be finished even after the patient feels better. Stopping early leaves the strongest bacteria alive, and these can multiply into a resistant strain that the antibiotic can no longer control.

Example. Penicillin is a well-known antibiotic used against bacterial infections. A doctor may prescribe a seven-day course; the patient must take every dose to the end, because stopping on day three, when the symptoms ease, allows the surviving bacteria to recover and become resistant.

Confusion to avoid. Do not confuse an antibiotic with an analgesic. An antibiotic kills bacteria and treats the cause of a bacterial infection; an analgesic, such as aspirin or paracetamol, only relieves pain and does not kill any microbe. Nor should an antibiotic be expected to work on a viral illness.

The antibiotic is one of the medicines studied in this chapter, and questions often test the two key rules, no effect on viruses and finish the course, which are exactly the points SPM Chemistry looks for. The idea of antibiotic resistance also connects chemistry to a real public-health concern: using antibiotics carelessly, or stopping a course early, breeds bacteria that ordinary antibiotics no longer kill. Being able to explain why the whole course matters, in terms of the strongest bacteria surviving and multiplying, shows understanding well beyond simply naming the medicine.