Christmas tree

Question

Hello,

due to our daughter's (2 years old) CF diagnosis, we are wondering this year whether we can set up my real Christmas tree with a bowl of water, or should we use an artificial tree to prevent germs from forming in the water?

Answer

Dear questioner,

Your question concerns the risk that a child with cystic fibrosis (CF) could become colonized with Pseudomonas aeruginosa. This is an environmental bacterium that thrives in stagnant water.

Therefore, you are theoretically correct; Pseudomonas could multiply in the water bowl of the Christmas tree.

On the other hand, not every risk of contracting Pseudomonas can be quantified or avoided. If the child doesn't play with the water bowl or put their hands in it, but the bowl is placed out of reach under the Christmas tree, the risk should be negligible, especially since no aerosols are emitted from the water bowl, as is the case, for example, in a whirlpool.

In fact, we treat many children and adults with CF at our CF center, and this question has never actually come up before. I assume that the vast majority of our patients have a real Christmas tree.
Therefore, the water bowl shouldn't be directly accessible to the child, but otherwise you don't need to worry – Merry Christmas with your Christmas tree!

Best regards, Daniela d'Alquen

20.02.2026