Pathogenesis of Mycoplasmas 

• Most mycoplasmas invading humans and animals are surface parasites, found on the mucosal surface of the respiratory and urogenital tracts. 

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• Seven species of Mycoplasma are pathogenic to humans: M. pneumoniae, M. urealytium, M. genitalium, M. hominis, M. fermentation, M. penetrans and M. pirum

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• Most mycoplasmas depend on adhesion in order to infect host cells. Once they adhere to the host’s surface, it cannot be removed by mucous secretions or urine. 

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• Adhesion also allows toxic metabolites to be excreted by mycoplasma, resulting in tissue damage. Hydrogen peroxide and superoxide are both products of mycoplasma metabolism, generating both enzyme and DNA damage. 

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• Due to the absence of a cell wall, fusion between the membrane of mycoplasmas and its host cell occurs.

• The process of membrane fusion consequently changes the composition of the host cell membrane and its permeability. Once fusion occurs, hydrolytic enzymes enter the host cell causing damage.