Oral cavity staphylococci are a potential source of prosthetic joint infection.

To the Editor—Recently in Clinical Infectious Diseases, Berbari et al [1] provided the results of a study devised to assess the risk of prosthetic joint infection resulting from temporally related dental procedures and the role of antibiotic prophylaxis. They reported that 339 patients developed a prosthetic hip or knee infection. Upon culture, staphylococci were the most commonly encountered infecting organisms (Staphylococcus aureus in 95 cases [28%] and coagulase-negative staphylococci in 101 cases [30%]), and only 35 cases (10.3%) were caused by flora of potential oral or dental origin. The study's design limited the definition of potential oral/dental flora to b-hemolytic strepto-cocci, Peptostreptococcus species, Actino-myces species, viridans group strepto-cocci, Abiotrophia and Granulicatella species , and Gemella species. This construct may be flawed because it underestimates the significance of staph-ylococcal bacteria in the oral cavity. Their origin (eg, skin, nasal tract, gastrointestinal tract) may be in question, but it is known that some staphylococci are transiently resident in the oral cavity and that adherence mechanisms permit a portion of them to be retained in the periodontal pocket. Furthermore, because of microul-ceration of the sulcular and pocket lining epithelium and proximity to the bloodstream , bacteremias are quite possible, as is the resultant infection of a prosthetic joint. Specifically, older (aged у70 years), healthy (eg, no history of diabetes), non– denture-wearing individuals have been shown to have a higher isolation frequency () and proportion () of P ! .05 P p .056 staphylococci from their unstimulated whole saliva than younger persons [2]. Elderly institutionalized individuals also exhibit significantly greater concentrations of staphylococci in their saliva than age-matched home-dwelling persons [3]. The wearing of partial dentures increases the proportion of staphylococci in the saliva of older individuals [4]. Individuals (mean age, 59 years) with rheumatoid arthritis and concomitant xerostomia who require long-term immunosuppressive steroid therapy exhibit a high prevalence of S. au-reus (often resistant to penicillin) on the tongue and in the oropharynx [5]. Thus, elderly persons and those with rheumatoid arthritis—the 2 groups of individuals who very frequently require joint replace-ment—often harbor staphylococci in their oral cavity. For individuals with signs of chronic or acute dental infections, the presence of staphylococci species is even more significant. Among young healthy individuals (age, 32–59 years; mean age, 45 years) with periodontitis and evidence of both S. au-reus and Staphylococcus epidermidis in their subgingival sulci, the penicillin-resistant S. epidermidis is the predominant organism [6]. Individuals with …