公公 a Meningococcus is the only bacterium that frequently causes a rash, which is probably the most important clue to the diagnosis of meningococcal E meningItIs. It usually begins as diffuse erythematous maculopapular rash. As the ras」 sh evolves, petechiae and purpura appear primarily on the an ower extremities。 Meningococcus is the only bacterium that frequently causes a rash, which is probably the most important clue to the diagnosis of meningococcal meningitis. It usually begins as a diffuse erythematous maculopapular rash. As the rash evolves, petechiae and purpura appear primarily on the trunk and lower extremities