My daughter seems to always culture staph. I don't know that it is a precursor to pseudomonas, but my daughter did have pseudomonas for about 6 months, we couldn't get rid of it until she had a tune up. She is a bit different though as she is a late diagnosis (right before she turned 10) and so I have no idea if she had pseudomonas in the past. When she was diagnosed she cultured MRSA, and I would be more concerned that staph could lead to MRSA not sure if that is the case either, but seems more likely as MRSA is a staph bacteria that is resistant to drugs usually used to treat staph....