Floor drain below the sink

Question

Dear expert team,

My son has CF. In the bathroom in his school, directly under the sink where people stand when washing hands, there is a drain in the floor (much like the ones often found in public showers). One can see that there is always water standing in this drain (which must be rather “old,” since new water will only be flushed in when the floor is cleaned).

I am worried that my son, who is standing right above the drain when washing his hands, could inhale some aerosols that could rise when water from the tap flows into the sink and the drainage system below, and that this could ultimately lead to a colonization of his lungs with Pseudomonas.

How high do you estimate the health risk?

Many thanks for your answer and kind regards.

Answer

Dear questioner,

Unfortunately, the health risk in the case you describe can not be judged concretely, as the actual bacterial exposure and the hygiene conditions present can not be estimated precisely. The typical bacterial germs in CF are environmental germs and water bugs and are transmitted mostly via drops (aerosols). The risk of transmission and possible subsequent infection depends on many factors (e.g. germ count, contact time, patient’s susceptibility, etc.). Unfortunately, in most cases of a positive germ test in CF patients, the actual source of the infection can not be determined, so that at this point only general recommendations for avoiding germ exposition can be made, taking into account that daily life should not be unreasonably limited. There are guidelines summing up the recommendations for hygienic behaviour in CF [translator’s note: a link to guidelines in German given in the original answer was not included in the translation]. In the domestic sphere, Pseudomonas has mostly been found in drains and siphons. It is conceivable that the germ count will increase over time in the water reservoir of the drain you are describing. According to what you are saying, though, it is not entirely clear to me how using the sink should lead to the building of aerosols in the floor drain. Therefore, and since there is no direct contact with the drain, the general risk of infection does not seem to be heightened to me. The sink’s siphon might be contaminated with CF-relevant germs as well. One option to avoid exposition when washing hands at “public” sinks (I would include the school here) would be hygienic hand disinfection and carrying around a small amount of disinfectant.

Kind regards
Michael Hogardt

29.10.2012