Table 2.

Prioritization of candidate virulence factors for investigation according to Falkow’s postulates.

Priority	Candidate virulence factor	Comment
1	L-alpha-glycerophosphate oxidase (GlpO)	Knock out mutants are available for M. mycoides subsp. capri, the role of this candidate virulence factor requires immediate investigation, as it is dispensable for virulence in M. gallisepticum
2	MIB-MIP system	Knock out mutants are already available for M. mycoides subsp. capri, in vivo activity has been proven and this is a top candidate virulence factor
3	Different DUF groups of lipoproteins	Individual lipoproteins and pathogen specific DUF groups of lipoproteins need to be tested for their role in virulence
4	Variable surface proteins	Have been shown in vitro and in vivo to be functional in mycoplasmas
5	Oligopeptide/dipeptide (opp/dpp) ATP-binding cassette (ABC) transporter	Has been shown in M. agalactiae to be a candidate virulence factor
6	6-phospho-beta-glucosidase (Bgl)	Correlations indicate a role in cytotoxicity