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Sites in the oropharynx reached by different methods of using mouthwash: clinical implication for oropharyngeal gonorrhoea prevention
  1. Kate Maddaford1,
  2. Christopher K Fairley1,2,
  3. Sabrina Trumpour1,2,
  4. Mark Chung1,
  5. Eric P F Chow1,2
  1. 1 Melbourne Sexual Health Centre, Alfred Health, Melbourne, Victoria, Australia
  2. 2 Central Clinical School, Monash University, Melbourne, Victoria, Australia
  1. Correspondence to A/Prof Eric P F Chow, Central Clinical School, Monash University, Carlton, VIC 3053, Australia; eric.chow{at}


Objectives Oropharyngeal gonorrhoea is increasing among men who have sex with men and is commonly found in the tonsils and at the posterior pharyngeal wall. To address this rise, investigators are currently trialling mouthwash to prevent oropharyngeal gonorrhoea. We aimed to determine which parts of the oropharynx were reached by different methods of mouthwash use (oral rinse, oral gargle and oral spray).

Methods Twenty staff at Melbourne Sexual Health Centre participated in the study from March to May 2018. Participants were asked to use mouthwash mixed with food dye, by three application methods on three separate days: oral rinse (15 s and 60 s), oral gargle (15 s and 60 s) and oral spray (10 and 20 times). Photographs were taken after using each method. Three authors assessed the photographs of seven anatomical areas (tongue base, soft palate, uvula, anterior tonsillar pillar, posterior tonsillar pillar, tonsil, posterior pharyngeal wall) independently and scored the dye coverage from 0% to 100%. Scores were then averaged.

Results The mean coverage at the sites ranged from 2 to 100. At the posterior pharyngeal wall, spraying 10 times had the highest mean coverage (29%) and was higher than a 15 s rinse (2%, p=0.001) or a 15 s gargle (8%, p=0.016). At the tonsils, there was no difference in mean coverage between spray and gargle at any dosage, but spraying 20 times had a higher mean coverage than a 15 s rinse (42% vs 12%, p=0.012).

Conclusion Overall, spray is more effective at reaching the tonsils and posterior pharyngeal wall compared with rinse and gargle. If mouthwash is effective in preventing oropharyngeal gonorrhoea, application methods that have greater coverage may be more efficacious.

  • gonorrhoea
  • posterior oropharynx
  • mouthwash use methods

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  • Handling editor Tristan J Barber

  • Twitter @EricPFChow

  • Presented at Some data of this work were presented as a poster presentation at the 2018 IUSTI Asia Pacific Sexual Health Congress, Auckland, New Zealand, 1 – 3 November 2018.

  • Contributors EPFC and CKF designed the study. MC and KM took all the participant photographs. EPFC, CKF and KM conducted the analysis. KM wrote the first draft of the manuscript. EPFC and CKF assisted with data analysis and interpretation. All authors revised the manuscript critically for important intellectual content and approved the final version.

  • Funding This study was supported by a National Health and Medical Research Council (NHMRC) project grant (GNT1122514). EPFC was supported by the NHMRC Early Career Fellowship (GNT1091226).

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval Ethics approval was obtained from Alfred Hospital Ethics Committee, Melbourne, Australia (number 116/18).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement All data relevant to the study are included in the article or uploaded as online supplementary information.