The Impact of Sialidases on the Urogenital Tract

Student thesis: Master's ThesisMaster of Science by Research (MScR)


Sialidases are enzymes which modify carbohydrate chains on cell membranes and glycoproteins
by removing sialic acid residues. Raised sialidase activity is associated with a condition of the
female genital tract called bacterial vaginosis. Bacterial vaginosis is associated with various
health problems, including infertility. In this study we sought to determine whether variations
in sialidase activity could be detected in samples from the male urogenital tract and if so,
whether changes could be linked to sexual health. Using a fluorogenic substrate we were able
to measure the sialidase activity in semen samples taken from both fertile and infertile men. It
was found that almost 20% of men visiting a fertility clinic had high sialidase activity in their
semen, whilst this was the case for only around 10% of fertile men. It appeared that high
sialidase activity had various effects on the semen, including reducing seminal viscosity and
removing streaks from the semen. In addition, it appeared that sialidase activity was associated
with an increased seminal abundance of Prevotella, a bacterial genus known to contribute to
sialidase production in bacterial vaginosis. Finally, we attempted to determine the potential
effect of raised sialidase activity on Neisseria gonorrhoeae, the causative agent of a known
urogenital infection. It was found that removal of sialic acid from the surface of N. gonorrhoeae
caused reduced sensitivity to antibiotics, potentially making the infection harder to treat in
patients with raised urogenital sialidase activity.
Date of Award19 Mar 2019
Original languageEnglish
Awarding Institution
  • University of Bristol
SupervisorDarryl J Hill (Supervisor) & Patrick Horner (Supervisor)

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