Crohn's is not caused by bacteria. It is an autoimmune disease. Your girlfriend's own immune system is attacking her own intestines. This is not related to bacteria, viruses, or anything else that could be caught by anyone else. It is just a malfunction of her own body systems. She didn't catch it anywhere, and she can't transfer it to you no matter what you do with her.
thanks for input but i doubt very much she has round worm or for that matter anyone with crohns would have. i actually have underlying gastro condition and my concern is genuine as i love this lady very much and need to be better informed re bacteria an such which could possibly cause issues with with my health and i apologise if my questions seems self centered, as i say my concerns are genuine. i read everywhere that no crohns is not contagious but no one can qualify this, thanks again