Spread your germs is a skill point gained by infecting 30 enemies on Mylon. The best way to get it is to use the Infecto-Bomb, the level 5 Infector. If you infect every enemy, you should obtain the skill point about 3 quarters of the way through the level.
In the high-definition re-release on the PlayStation 3, a trophy unlocks for completing this skill point. The trophy is named Penicillin Anyone?.
- Ratchet & Clank: Up Your Arsenal (first appearance)