ORAL STAPHYLOCOCCUS IN OLDER SUBJECTS WITH RHEUMATOID-ARTHRITIS

OBJECTIVE: To determine if Staphylococcus aureus and Staphylococcus ep idermidis, etiologic bacterial agents to late prosthetic joint infecti ons (LPJI), are more prevalent in the oral flora of older individuals with rheumatoid arthritis (RA) than in an age and gender-matched nonar thritic control population (NA).DESIGN: Cultures were obtained from th e nares, oropharynx, saliva, tongue, and gingival crevice, and the res ults were compared between older patients with RA and controls. SETTIN G: University of Michigan Medical Center, Ann Arbor, VA Medical Center , and University of Michigan School of Dentistry. PARTICIPANTS: A tota l of 111 community-dwelling subjects with a diagnosis of RA and 83 gen der-matched control subjects. MEASUREMENTS: Colistin nalidixic acid ag ar plates with 5% sheep's blood were inoculated and incubated. Isolate s were speciated using the API Staph Trac(R) micro method and catalase and coagulase tests. MAIN RESULTS: Individuals with RA had a higher p revalence of S. aureus isolated from the oral cavity. However, only th e oropharynx and tongue revealed higher rates; all other sites were in significant. The presence of oral S. aureus was associated with xerost omia. Staphylococcus epidermidis was not detected from any of the oral sites sampled. Sixty-two percent (10/16) of the S. aureus isolates fr om the RA subjects were resistant to penicillin and ampicillin, wherea s none were resistant to a cephalosporin. CONCLUSIONS: These findings suggest that rheumatoid arthritis may be a risk factor for LPJI in old er prosthetic joint patients undergoing invasive dental procedures in the poste rior oral cavity. This increased risk is caused, in part, by a higher prevalence of S. aureus in the posterior oral cavity. The pr evalence and the antibiotic resistance of S. aureus must be considered when determining the need for chemoprophylaxis.