Dr. Carter believes the key to success was combining two antibiotics – rifampin, which uniquely weakens Chlamydia, so another antibiotic, in this case either doxycycline or azithromycin, can finish the bacteria off.

“I think rifampin is a necessary treatment,” says Dr. Carter. “It’s the only drug that we’re aware of that can inhibit Chlamydia’s ability to produce this heat shock protein. So if you can inhibit that protein, we think the cell is more susceptible to antibiotic therapy.”

The study did not compare the two different antibiotic combinations so researchers don’t know if one performed better than another.

“That’s the natural follow up to find the best combination and best dose of therapy,” Dr. Carter says. “This study answered that it worked and you can clear the infection, but it doesn’t answer the important question of which antibiotic is best and what’s the most efficacious chronic dosing.”

Dr. Carter does caution that people shouldn’t look at this study and think antibiotics can cure anything. “These are very specific to Chlamydia-induced arthritis,” he says. “So it’s important and this is a potential for cure, but only for this very specific condition.”

The study was so well designed that the results are likely to change clinical practice.

“I’m pretty impressed. I used to be a skeptic about whether this could work but now I’m not so skeptical,” says Rex McCallum, MD, professor of Medicine at Duke University Medical Center in Durham, N.C., who was not involved in the study.

“I think it’s impressive enough to me personally that when I treat the next person that had reactive arthritis, I would give serious thought to giving them a longer course of antibiotics like they did in the paper.”

Dr. McCallum says his main criticism of the study is that it followed a small number of patients, although he acknowledges these cases can be difficult to find.