Antibiotic overuse makes microbes resistant

For some time, we've been warned that overuse of antibiotics could make some microbes resistant to them. Now a new study published in the British medical journal The Lancet adds some specifics to that warning.

For their study, researchers at University of Antwerp Hospital in Belgium recruited several hundred healthy volunteers. Throat swabs from all of the participants were cultured and assessed at the beginning of the study for the presence of antibiotic-resistant Streptococcal bacteria. Then the volunteers were divided into three groups. On group took an antibiotic called azithromycin; the second group took an antibiotic called clarithromycin; the third group were given a placebo.

Several times, over a period of 180 days, more throat swabs were cultured from all of the groups to see if the number of antibiotic-resistant bacteria had changed. Each time they tested, they found a significantly increased the proportion of antibiotic-resistant bacteria in both groups that took the antibiotics, compared with the placebo group.

Translation: Taking antibiotics unnecessarily does indeed contribute to bacterial resistance to the drugs. Don't take (or ask your doctor for) antibiotics except when they are needed to combat a specific bacterial infection.

And remember, antibiotics are only effective against specific bacterial infections, not viruses, so don't take an antibiotic to treat a cold or the flu. It won't help your infection, and may end up doing more harm by promoting antibiotic-resistance in bacteria that may be lurking in your body.

Source: Malhotra-Kumar, S., Lammens, C., Coenen, S., Van Herck, K., & Goossens, H. (2007). Effect of azithromycin and clarithromycin therapy on pharyngeal carriage of macrolide-resistant streptococci in healthy volunteers: a randomised, double-blind, placebo-controlled study. The Lancet, Vol. 369, pp. 482-490. [Free registration may be required to view the article]