Identification and Characterisation of Virulence Genes in Mycoplasmas
Glenn F. Browning, Amir H. Noormohammadi and Philip F. Markham
from: Mollicutes: Molecular Biology and Pathogenesis (Edited by: Glenn F. Browning and Christine Citti). Caister Academic Press, U.K. (2014)
The pathogenesis of most mycoplasmoses is predominantly attributable to the immunopathological response of the host to the persistent presence of these pathogens. Therefore, virulence genes in mycoplasmas are probably best defined as those that are not necessary for growth in vitro, but that are required for optimal colonisation of, persistence in or pathological effects on the host, including those genes whose primary function appears to be ensuring optimal nutrient acquisition in vivo. While the full array of virulence genes is far from being defined in any one mycoplasmal pathogen, there has been significant progress in recent years in defining the roles of adhesins, invasion, toxin production, immune evasion, immunostimulation and immunosuppression in some mycoplasmas, and in characterising some of the genes involved in these processes. In addition, it has become clear that several systems for acquisition and utilization of specific nutrients are required for optimal pathogenicity, in some cases because these nutrients contribute to the generation of toxic metabolites, while in others presumably because they facilitate persistence in a nutrient limited environment. Most recently some of the mechanisms used to regulate transcription of virulence genes have been identified, and the complexity of post-translational control of virulence factors is beginning to be revealed. These recent findings have demonstrated that mycoplasmas are far more complex pathogens than their superficially simple genomes would suggest read more ...