The bacterial infection known as scarlet fever has been on the rise in Britain, with cases also increasing in parts of Asia. Now new research suggests that the easily treatable infection might not always be so benign: It shows signs of antibiotic resistance.

Scarlet fever (or scarletina) is caused by group A Streptococcus bacteria, and it most commonly affects children between the ages of 5 and 12. Only a small number of people who have strep throat caused by group A strep will develop scarlet fever, which is named for the red, sandpaper-like rash it causes. The disease is unpleasant -- and before the invention of antibiotics, it was quite deadly -- but these days, though there is no vaccine, it's easily treated with antibiotics.

In a study published Monday in the journal Scientific Reports, researchers from the University of Queensland caution that the surge in scarlet fever cases may pose an unexpected threat.

An analysis of samples from 25 confirmed scarlet fever patients (as well as nine patients who had some kind of group A strep infection) from China and Hong Kong confirmed that a strain that emerged in the 1980s is a common source of infection. Penicillin is a fine treatment for these cases, but the researchers found evidence of resistance to other antibiotics like tetracycline, erythromycin and clindamycin. This poses an immediate problem for patients who are allergic to penicillin, but it's worrisome for other patients as well. There's no telling when the bacteria could begin to show resistance to penicillin, leaving doctors with few treatment options.

The increase of antibiotic resistance in bacteria shouldn't surprise us. As antibiotics have become more common in the environment — in humans being treated for disease as well as in farm animals and wastewater — more bacteria have been exposed to them. That means that the bacteria which survive are likely to be invulnerable to the drugs we take, which is obviously a problem for those who are ill. Antibiotic resistance causes an estimated 2 million illnesses and 23,000 deaths every year in the United States.

"We now have a situation which may change the nature of the disease and make it resistant to broad-spectrum treatments normally prescribed for respiratory tract infections, such as in scarlet fever," lead study author Nouri Ben Zakour said in a statement. The findings, she said, suggest that monitoring the spread and evolution of this bacteria is of the utmost importance.

The fact that penicillin still seems to work in most cases of scarlet fever means that it isn't time to panic. But this is just the latest example of the ticking time bomb that is antibiotic resistance.

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