How common is clostridium tetani on plastic, specifically on a plastic swiffer-type mop in a house garage?

It is everywhere most of the tine. Why don’t ask?

Clostridium tetani are bacteria which are usually found in soil, dust, & manure. This bacteria enters the body via breaks in the skin, generally cuts or puncture wounds which are caused by contaminated objects. It's possible a mop could be contaminated with soil or dust which has this bacteria in it. I wish you well with your health!