PIP is not caused by bacteria. If that were the case, youad be bed ridden in a hospital right now with an IV of antibiotics pumping through you and a massive abscess at the injection site. PIP is caused by many different factors: the type of oil used in the gear, the concentration of the gear, solvents used, cosolvents used, sterilizers in the gear, and most importantly: your body's own response and reaction to the liquid itself.