Prevalence of Nasal Colonization with Staphylococcus aureus in Patients with Rheumatoid Arthritis

Objetive: Patients with Rheumatoid Arthritis (RA) and nasal carriers of Staphylococcus aureus have an increased risk of developing infections caused by S. aureus. Our objective was to determine the prevalence of S. aureus nasal colonization in patients with RA and its relationship to RA treatments.

Two hundred and seven patients with RA and 37 healthy controls were prospectively included in a cross-sectional study. A nasal secretion sample was collected by swab from both anterior nostrils and was referred to the hospital's microbiology department for culturing.

The mean age of the patients (168 women, 78%) was 61 ± 12 years old. The mean disease duration was 13 ± 10 years. Seventy-six percent of the patients were positive for Rheumatoid Factor (RF), and 71% were positive for Anti-citrullinated Peptides Antibodies (ACPA). Seventy percent had joint erosions. The mean DAS28 was 3.1 ± 2.2. S. aureus nasal colonization was found in 36% of the RA patients and 35% of the controls. Three patients and no controls were resistant to oxacilin/ mupirocin. The patients who were positive for ACPA had a higher prevalence of S. aureus colonization (43% vs. 17%; p < 0.05). The colonization prevalence in the patients treated with glucocorticoids was 32% (n: 133); methotrexate and/or leflunomide, 37% (n: 167); anti-TNF agents, 46% (n: 54), p < 0.05 versus patients not treated with anti-TNF agents; rituximab, 22% (n: 18); tocilizumab, 39% (n: 18).

The prevalence of S. aureus nasal colonization in patients with RA does not appear to be greater than that of the general population. Anti-TNF agents might confer a higher prevalence of colonization.