I would think they are ALL trained in isolation precautions. Even I am, as a housekeeper, though I don't do patient care. We know how to handle infectious wastes of all kinds, as well as knowing all the different isolation precautions for cleaning rooms. Nursing assistants especially should be trained in this, as they handle the bulk of the "dirty" parts of patient care where I work, when it comes to hygiene, body fluids (assisting with bedpans and bathroom trips more so than the nurses) and bedding changes.