Mycoplasma mycoides subsp. capri encodes multiple pathways for hydrogen peroxide production

Several Mollicutes species import glycerol and related molecules as carbon sources, resulting in the release of hydrogen peroxide (H₂O₂), which has been suggested as a pathogenicity mechanism. We systematically deleted genes encoding components of the H₂O₂ pathways in Mycoplasma mycoides subsp. capri GM12 to get insight into the role of candidate factors constituting the pathways. As expected, glycerol metabolism in GM12 is associated with the highest H₂O₂ production compared with glycerophosphocholine. The absence of either L-alpha-glycerophosphate oxidase (GlpO) or the glycerol uptake facilitator GlpF, which is the main glycerol importer in GM12, ceased H₂O₂ production. However, our data did not support any role for the presumed glycerol transport system, GtsABC in glycerol- or glycerophosphocholine-dependent H₂O₂ production. Caprine peripheral blood mononuclear cells (PBMCs) did not show increased cytotoxic effects upon incubation with GM12 in the presence of glycerol, which does not support H₂O₂ to be a primary pathogenicity mechanism in GM12.