Sewage and water that stands around for long periods without disinfectant are both risky, because they tend to grow not just Pseudomonas, but also other bacteria, such as Serratia, that can really be a problem for people with cf. (Incidentally, although it may sometimes seem that way, Pseudomonas is truly <u>not</u> everywhere; I've had water, water filters, toothbrushes, and nebulizer cups cultured at various times and have gotten only two positives for Pseudomonas -- one from a dirty pre-filter of a water purification system and the other from tap water after garden dirt had gotten in through broken pipes.) According to the Centers for Disease Control and Prevention, the tubing that dental assistants use to spray water into your mouth is often grossly contaminated with Pseudomonas, and it's likely to be in the biofilm form (i.e., mucoid), which is notoriously resistant to antibiotic treatment. So Jordan takes a little bottle of water to the dentist's to rinse with.
Not just cigaratte smoking, but other forms of air pollution (smog, vehicle exhaust) are especially bad for those with cf. Wood stoves and fireplaces are among the worst sources, but small airborne particles are generally problematic because they tend to get trapped in the cf lung, which is too "sticky" to be able to clear them effectively. Similarly, animal droppings can be big trouble if they get stirred up (that's how people typcially get hantavirus).
Bambi, Jordan's mom (also a public health scientist)