Background:
Orogenital exposure to GC can result in predominately asymptomatic pharyngeal infection. Though pharyngeal pathology is uncommon, GC may be transmitted from the pharynx to the genital tract of sex partners. Swab specimens are typically obtained from the posterior pharyngeal wall and tested for the presence of GC by nucleic acid amplification tests (NAATs) or culture. NAATs may be preferred owing to increased sensitivity and availability. Since NAATs can detect GC in fluid specimens, they may also be useful with oral lavage specimens that are less invasive than swabs

Objective:
To determine if GC can be detected in commercial mouthwash spiked with known amounts of the organism.

Method:
Three commercial mouthwash fluids were inoculated with GC to a final estimated concentration of 107 colony forming units per milliliter (CFU/mL). Ten-fold dilutions were prepared ranging from 107 to 10 CFU/mL. These specimens (n=21) were tested for GC following incubation at ambient room temperature for 2 hours, 1 day, 2 days and 12 days by a NAAT (Aptima, GenProbe). Mouthwash that was not spiked with GC was also tested.

Result:
All diluted specimens were positive for GC at all time points while uninoculated mouthwash remained negative. There was no difference in the brand of mouthwash with respect the preservation of GC for detection.

Conclusion:
GC can be detected in commercial mouthwash after being kept for up to 12 days at room temperature. These in vitro data demonstrate the potential utility of mouthwash for the diagnosis of pharyngeal GC infections.

Implications:
Collection of mouthwash fluid and subsequent testing for GC may represent a more comprehensive sample of the pharynx since it would not be restricted to a discrete area of mucosa. Mouthwash specimens may be easier to obtain and could possibly be self-collected. Specimen collection for testing the in vivo application of this method has begun.