Pharyngeal infection with Neisseria gonorrhoea represents a large, asymptomatic reservoir of infection, and is thought to be an important driver of transmission among men who have sex with men (MSM). Which sexual activities drive the transmission of gonorrhoea between the pharynx and other sites? Could it be oral sex? Rimming? Chemsex?

Kit Fairley, Professor of Public Health at University of Melbourne and Director of Melbourne Sexual Health, wonders if it might be all even more surprising - kissing. But not just any kissing - 'proper kissing with a tongue and all the rest of it.'

In  a thought-provoking presentation, Fairley points out that gonorrhoea rates are highest among young MSM, and fall with age. While this might suggest a degree of acquired immunity to gonorrhoea, it might simply reflect changes in kissing throughout the age spectrum. Rates of oral sex, the traditionally accepted route of transmission to the pharynx, do not fall with age. Furthermore, penile-oral sex relies on urethral gonorrhoea as the vehicle for transmission between pharynges of different partners. Urethral gonorrhoea, however, is almost always symptomatic, and urban MSM are quick to access health services early in the course of gonococcal urethritis. 'The penis' says Fairley 'is an innocent bystander in this whole affair.'

How plausible is this? Neisseria meningitidis, the organism from which N. gonnorhoeae evolved aeons ago, is readily transmitted through saliva, and kissing is a well-recognised and important route of transmission for the meningococcus. N. gonorrhoeae, or at least it's DNA, can be readily detected in saliva of those with pharyngeal infection. 

If this hypothesis is correct, something as simple as antibacterial mouthwash might crack the transmission dynamics of gonorrhoea and spare the need for cephalosporins. And besides, who wouldn't prefer to kiss a man with fresh, minty breath?