Staphylococcus aureus and the oral cavity: a 10 year analysis

Methods: A hand search was conducted of laboratory work sheets compiled from S. aureus specimens submitted to a regional oral microbiology diagnostic laboratory from 1998-2007. Data collected included patient age, referring clinical unit, clinical presentation, specimen type and sensitivity to methicillin. MRSA genotyping data was recorded where possible.

Results: For the period 1998-2007, there were 11,312 specimens submitted to the laboratory. S. aureus was isolated from 1,986 specimens, of which 1,782 (90%) were sensitive to methicillin (MSSA) and 204 (10%) were resistant to methicillin (MRSA). There was an increasing incidence of S. aureus with age particularly in the >70 years age group. The most common specimen type from which MSSA was isolated was an oral rinse (34%) whilst for MRSA isolates this was a tongue swab (27%). The clinical descriptions most commonly reported for MSSA isolates was angular cheilitis (24%) however significant proportions were attributed to other candidal infections (13%), erythema/swelling (11%) and painful/burning mouth (8%). There were a total of 142 MRSA specimens. The most common genotypes were EMRSA15 (40%) and EMRSA 16 (14%).

Conclusion: This retrospective study further reinforces previous findings that the oral cavity may represent an important site of S. aureus colonisation or infection that hitherto has not been fully acknowledged. Further prospective studies are required to clarify the role of S. aureus in oral health and disease.