TNF and infection: Some examples of these potential virulence factors are: (i) hemolysin—lyses erythrocytes and creates anaerobic environment at the site of infection, stimulates the production of IL-1β and TNFα; (ii) ABC transporters—facilitates iron uptake, related with antibiotic resistance; (iii) lipooligosaccharides synthesis—involved in immune system evasion, attachment to epithelial tissue, mediator of the proinflammatory response; (iv) cytolysin—forms pores in cell membrane, induces apoptosis, promotes cellular invasion, triggers iNOS and cytokine release (Additional file 18).