Antibiotic regimen found effective for Chlamydia-induced reactive arthritis

WASHINGTON - A combination of antibiotics has been found to be an effective treatment for Chlamydia-induced reactive arthritis, a major step forward in the management, and possibly cure, of this disease, say researchers from University of South Florida College of Medicine.

The study results are published in the May issue of Arthritis and Rheumatism, a journal of the American College of Rheumatology.

Reactive arthritis (ReA), also known as Reiter’s syndrome, occurs in response to an infection. According to National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), the bacterium most often associated with ReA is Chlamydia trachomatis. Respiratory infections with Chlamydia pneumoniae can also trigger ReA, while associated infections in the digestive tract include Salmonella, Shigella, Yersinia, and Campylobacter. ReA symptoms usually last 3 to 12 months, although symptoms can return or develop into a long-term disease. In the past it was thought that only a small percentage of people would experience chronic symptoms of ReA.

However, more recent data suggests that as many as 30 percent -50 percent of patients could develop a chronic form of the disease. In chronic ReA, symptoms can be severe and difficult to control with treatment, which could lead to joint damage.

The use of long-term antibiotic treatment for patients with ReA is controversial. Several reported studies have indicated that prolonged antimicrobial monotherapy is not efficacious, while other studies suggest there might be a benefit, specifically with early-stage Chlamydia-induced ReA.

The study led by J.D. Carter, M.D., focused on combinations including 2 antibiotics found to have specific effects on the Chlamydia bacteria. The first, rifampin, has excellent tissue penetration, an important weapon against intracellular pathogens such as Chlamydia. Rifampin also has been shown to interfere with chlamydial gene transcription, including the heat-shock proteins (HSPs), which can ultimately lead to the demise of the infected cell. Dr. Carter explains why this is important. “Combining this effect with antibiotics that block chlamydial protein synthesis (e.g., doxycycline or azithromycin) may allow for successful eradication of the cell harboring persistently infecting intracellular organisms. A recent pilot study conducted by our group suggested that prolonged treatment with a combination of doxycycline and rifampin significantly improves symptoms of chronic undifferentiated spondylarthritis (SpA) (with a special focus on Chlamydia) compared with doxycycline alone. The goal of the present study was to further investigate whether a 6-month course of combination antibiotics, one of which is rifampin, is effective in the treatment of patients with chronic Chlamydia-induced ReA.” (ANI)