Determination of virulence factors in avian Mycoplasma species

Mycoplasma gallisepticum and M. synoviae are economically important bacteria infecting poultry worldwide; however, information about the molecular basis of their pathogenesis is limited. Control of Mycoplasma infections consists of eradication and prevention, vaccination or medication. Live vaccine strains are available against M. synoviae and M. gallisepticum, but information about the mechanisms of their attenuation is limited. The increasing number of antibiotic resistant Mycoplasma strains demands new antimicrobial strategies. The main aim of the present project is to provide essential data about the virulence for the improvement of the control of avian mycoplasmosis. Putative virulence-related genes will be identified by the analysis of whole genome sequences of M. gallisepticum and M. synoviae virulent and attenuated strains. Targeted gene disruption will be introduced for the analysis of the effect of selected genes in in vitro experimental infections. This method will also promote future genetic studies. Genes responsible for the attenuation of vaccine strains of the two species will be identified and analyzed to provide basic and essential information for vaccine development and the control of vaccine usage. Virulence factors shared by the two avian Mycoplasma species will be explored and analyzed to enable the development of new vaccines and a new antibacterial approach, the use of antivirulence drugs against avian mycoplasmosis. The determined common virulence factors of the two species may serve as potential targets for cost-effective antivirulence drugs suitable for both preventing and treating mycoplasmosis in poultry.