Edwin Klebs
He was the first to identify a bacterium that causes diphtheria , which was called Klebs–Loeffler bacterium ( now "Corynebacterium diphtheriae" ) . 
<triplet> diphtheria <subj> Corynebacterium diphtheriae <obj> has cause <triplet> Corynebacterium diphtheriae <subj> diphtheria <obj> has effect