Dr. John Carter of the University of South Florida College of Medicine led the National Institutes of Health-sponsored investigation and said the findings represent a major step toward management, and possibly cure, of the disease.
"Our findings lend hope that eradication of this persistent infection is attainable and a possible cure exists," said Carter, an associate professor of medicine.
The scientists said reactive arthritis, also known as Reiter's syndrome, is an autoimmune disorder that develops in response to an infection elsewhere in the body. That type of arthritis is most commonly caused by the bacteria Chlamydia trachomatis, usually acquired through sexual contact, or Chlamydia pneumoniae, which can trigger respiratory infection.
The research team devised a new prolonged course of combination antibiotic treatment, which attacked two different pathways that allow Chlamydia infection to persist in the joints.
The double-blind, placebo-controlled trial involved 42 patients randomly assigned to one of three treatment groups -- rifampin plus doxycycline, rifampin plus azithromycin, or placebo.
The researchers said patients treated with the combination antibiotics improved significantly more in measures of the swelling and tenderness of joints and symptom assessment.
The trial that included the Louisiana State Health Science Center, the University of Toronto and Wayne State University appears in the journal Arthritis & Rheumatism.