Monday Micro – Semen and the twitchy clap

By Siouxsie Wiles 10/03/2014

Neisseria gonorrhoeae is the bacterium responsible for the sexually transmitted infection gonorrhoea, also known as the clap. Symptoms often include pain when peeing and a nasty discharge from your nether regions, although some people can be asymptomatic. The microbe isn’t hugely fussy about where it causes an infection, so you can also get gonorrhoea of the throat and anus if that’s where the bacteria are deposited.

Despite the fact that gonorrhoea can be prevented by using condoms, there are apparently more than 100 million estimated new cases worldwide each year. Unfortunately N. gonorrhoeae is becoming increasingly resistant to antibiotics, so researchers are trying to find out more about how the microbe is transmitted and exactly how it causes infection to develop new strategies to combat it.

Mark Anderson and colleagues have just published a paper in the open access journal mBio showing that various proteins in the fluid of semen makes N. gonorrhoeae mobile, through a mechanism called twitching motility. This is where the bacterium rapidly extends and retracts hairlike appendages found on its surface to make it move. The researchers also found that N. gonorrhoeae forms little microcolonies when exposed to seminal proteins, making it stick better to human cells. This work shows that the semen environment changes the bacterium to prime it for transmission between people.

In case you need an incentive to use a condom, here’s a movie of twitching motility in action, for another bacterium called Pseudomonas aeruginosa. So guys, you could have those little critters twitching around in your semen. Seriously. If you ever have a discharge, go see a doctor.


Anderson MT, Dewenter L, Maier B, Seifert HS. 2014. Seminal plasma initiates a Neisseria gonorrhoeae transmission state. mBio 5(2):e01004-13. doi:10.1128/mBio.01004-13.