TITLE:
Mycoplasma hominis Variable Adherence-Associated Antigen: A Major Adhesin and Highly Variable Surface Membrane Protein
AUTHORS:
Rebecca J. Brown, Victoria J. Chalker, Owen B. Spiller
KEYWORDS:
Mycoplasma hominis, Variable-Adherence Associated Antigen, Host-Pathogen Interaction, Surface Expressed Proteins
JOURNAL NAME:
Advances in Microbiology,
Vol.4 No.11,
September
5,
2014
ABSTRACT: Mycoplasma hominis is a member of the genus mycoplasma and has only been isolated
from humans. It is most frequently isolated from the urogenital tract in the
absence of symptoms, but has been isolated from wounds, brain abscess, inflamed
joints, blood and placenta from pregnancy with adverse outcomes (especially
preterm birth and occasionally term stillbirth). Controversy surrounds whether
this organism is a commensal or a pathogen; however, Mycoplasma hominis has been shown to induce preterm birth and
foetal lung injury in an experimental primate model as a sole pathogen. These
bacteria are known to exist as a parasitic infection, due to a number of
missing synthetic and metabolism pathway enzymes from their minimal genome;
therefore, the ability to adhere to host cells is important. Here we provide a
review that clarifies the different nomenclature (variable adherence-associated
antigen and P50) that has been used to investigate the major surface adhesin
for this organism, as well as reported mechanisms responsible for turning off
its expression. Variation in the structure of this protein can be used to
separate strains into six categories, a method that we were able to use to
distinguish and characterise 12 UK strains isolated from between 1983 and 2012.
We propose that the Vaa should be used in further investigations to determine
if commensal populations and those that are associated with disease utilise
different forms of this adhesin, as this is under-studied and identification of
pathogenic determinants is overdue for this organism.