The Collaborative International Dictionary of English v.0.48:

Inoculator \In*oc"u*la`tor\, n. [L.: cf. F. inoculateur.]
   One who inoculates; one who propagates plants or diseases by
   inoculation.
   [1913 Webster]

WordNet (r) 3.0 (2006):

inoculator
    n 1: a medical practitioner who inoculates people against
         diseases [syn: inoculator, vaccinator]