<prompt> The most common organism causing meningitis is -StaphylococcusStreptococcusMycoplasmaPneumococcus  <response>: Ans. is D i.e., Pneumococcus o Two most common organisms causing meningitis in adults are pneumococci and meningococci. o Group B streptococci is the most common cause of meningitis in neonates followed by E.coli. 