RESISTANCE of Neisseria gonorrhoeae to antibiotics is well known, granting it the infamous title of being a ‘superbug’. Now, researchers from Oregon State University, Corvallis, Oregon, USA have identified a key protein that could provide a new target for antibiotics and potentially lead to the development of a therapeutic vaccine for gonorrhoea infection.
Gonorrhoea is one of the most common sexually transmitted diseases, with 78 million new cases diagnosed annually worldwide. Despite being asymptomatic in many cases, the disease can lead to significant health problems, particularly regarding reproduction. “The infections very often are silent. Up to 50% of infected women do not have symptoms, but those asymptomatic cases can still lead to some very severe consequences for the patient’s reproductive health, [including] miscarriage or premature delivery”, explained Prof Aleksandra Sikora, Oregon State University.
The infection overcomes the body’s first-line innate immune system by inhibiting the bactericidal effects of lysozymes. Previously, only one such lysozyme-inhibiting protein was known in the Neisseria genus, but during their study the team identified a second: surface-exposed lysozyme inhibitor of C-type lysozyme (SliC). The researchers explored the function of SliC both in culture and in a murine model. Mice infected with N. gonorrhoea were measured for SliC expression at 1, 3, and 5 days, with the results demonstrating that the anti-lysozyme role of SliC was integral to the bacteria’s virulence.
With this newly discovered protein confirmed as a key player in gonorrhoea infection, researchers are hopeful that the lysozyme inhibitor itself can be targeted to fight the disease. New drugs can now be developed inhibiting SliC and this knowledge could even be used to create a therapeutic vaccine. “This is the first time an animal model has been used to demonstrate a lysozyme inhibitor’s role in gonorrhoea infection. Together, all of our experiments show how important the lysozyme inhibitor is. This is very exciting”, concluded Prof Sikora.
