Medical Fun Facts Episode 4: The gonococcus

Medical Fun Facts Episode 4: The gonococcus

As I mentioned in episode 3, The gonococcus is closely related to the meningococcus, in fact, in many ways they could be regarded as a single species much in the same way some people consider Escherichia coli and Shigella spp. to be one species.

The formal name for the gonococcus is Neisseria gonorrhoeæ. It causes gonorrhoea or the clap.

In medical school we were taught that the gonococcus is a very delicate and fastidious microorganism however that is not always the case. While it is virtually impossible to be infected from gonococcal pus on a toilet seat, it is possible to get gonococcal conjunctivitis from flies (see the reference below).

Neonatal ophthalmic infection can occur during passage through the birth canal and there is speculation about autoinoculation from infected genitalia to eyes/conjunctivæ.

I expect the fly-borne infection relates to biological burden of infected sites with flies landing on areas contaminated by discharge or purulence and then landing on the conjunctivæ of someone close by.

On the subject of biological burden, we are taught that ideally specimens should be sampled from areas of columnar epithelium like urethral and endocervical cells rather than stratified squamous epithelium. In truth, my experience in the Northern Territory of Australia is that we could grow gonococci from high vaginal swabs, low vaginal swabs, introital swabs and pus that was found on the inner thigh. We could also grow gonococci from first pass urine that had been collected for nuclei acid amplification assays.

Another nice thing about gonococci is while most have an outer surface capsule, some strains do not and they are resistant to the effects of complement so they can disseminate and then form infections in joints or the heart or the brain. Disseminated gonococcal infection is not that uncommon. In women when the infection is left untreated, we sometimes see infection spread via the fallopian tubes into the peritoneum and then coating the surface of the liver and spleen to cause Curtis Fitz Hugh syndrome.

One thing that is becoming more common apart from urethral and cervical infection is rectal and throat gonorrhoea.

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An outbreak of non-sexually transmitted gonococcal conjunctivitis in Central Australia and the Kimberley region. Rex Matters, Ignatius Wong, and Donna Mak. Comm Dis Intell 1998;22:52–58