Mycoplasma hominis variable adherence-associated antigen: a major adhesin and highly variable surface membrane protein

摘要

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 hasbeen isolated from wounds, brain abscess, inflamed joints, blood and placenta from pregnancywith adverse outcomes (especially preterm birth and occasionally term stillbirth). Controversysurrounds whether this organism is a commensal or a pathogen; however, Mycoplasma hominishas been shown to induce preterm birth and foetal lung injury in an experimental primate modelas a sole pathogen. These bacteria are known to exist as a parasitic infection, due to a number ofmissing synthetic and metabolism pathway enzymes from their minimal genome; therefore, theability to adhere to host cells is important. Here we provide a review that clarifies the differentnomenclature (variable adherence-associated antigen and P50) that has been used to investigatethe major surface adhesin for this organism, as well as reported mechanisms responsible forturning off its expression. Variation in the structure of this protein can be used to separate strainsinto six categories, a method that we were able to use to distinguish and characterise 12 UKstrains isolated from between 1983 and 2012. We propose that the Vaa should be used in furtherinvestigations to determine if commensal populations and those that are associated with diseaseutilise different forms of this adhesin, as this is under-studied and identification of pathogenic determinantsis overdue for this organism.