also antigenic variance on the surface of the organism itself- from memory its either one strain of staph that is capable of this and maybe N. gono
not sure though
hahah you need some knowledge of bacteria and mechanisms by which they escape the "immunological radar" at times :p
hint: some research into microbiology texts would help kiddies with this question :)
forensic chem would be very full on- but thats just because i hate chemistry at times :p
but if you have the skill set to be a problem solver and retain lots of knowledge then id imagine it would be a very good course to be enrolled in.`