pneu·mo·ba·cil·lus 
(n′mō-bə-sĭləs, ny′-)
(n′mō-bə-sĭləs, ny′-)n. pl. pneu·mo·ba·cil·li (-sĭlī′)
A nonmotile, gram-negative bacterium (Klebsiella pneumoniae) that causes a severe form of pneumonia and is associated with other respiratory infections. Also called Friedländer's bacillus.