MYD88 and infection: Finally, alike the 3M, 4M and 5M mutants deficient in production of several toxins and virulence factors at a time, the Δfim and ΔfhaB mutants failed to transmit from infected index mice to co-housed MyD88 KO mice, as judged from the failure to establish a productive infection in nasal cavities of co-housed mice (Fig 13C).