Surg tech? I would advise against SIGG bottles...I've been through a couple where the plastic lining tore along the mouth of the bottle, meaning that water worked its way in between the lining and bottle every time I took a drink. That's just asking for some funk.

A couple of drops of bleach in the full bladder may work; don't use too much or it will taste like chlorine for a while. If it's sunny, leave it outside with a clothes hanger proping it open to dry out and let the UV kill of any residual bacteria. This usually works for my camelback.