Visit (tropical) orchid garden

Question

Dear Doctor,

Can a CF patient visit a tropical indoor garden? Or is there a risk to get a Pseudomonas infection?

Thanks a lot for your answer!

Answer

Dear questioner,
it can only hardly be estimated how high the (relative) risk of infection is in case of a visit of the tropical house of a zoo (resp. botanic garden etc.) e.g. also in comparison to other activities with a possible exposition to humid germs. The reason for this is, that for the judgment of this question there is hardly any microbiological data. It is without doubt that the high density of aerosols via a spray mist (mist producing device) in closed rooms could be a very effective way of transmission. Precondition for this is, however, that there is a burden with germs, whereby above all the amount and the kind of the burden with germs as well as the duration of exposition determine the risk of transmission of germs. As an example, on the basis of the German bathwater bylaw, which allows for 100ml of water in the bassin no detection of P. aeruginosa (among others), a visit of a public swimming pool can in general be recommended in spite of the increased formation of aerosols.
A burden with germs resp. a transmission can however never completely be excluded. This is even more true for tropical houses where, according to my knowledge, there are no specific/regular controls. The exact technical procedure (origin of the water, using of filters) is not known to me (see also Zietz et al., 2006; here the burden with germs of spray mist devices at the example of greenhouses are described).
As a certain risks remains, your question probably aims directly at the possibilities to minimize this risk during the visit. The most effective and simplest measure would be the wearing of a face mask. A surgical face mask provides a relative protection, is however not dense for aerosols. FFP2-masks are fitting tightly and provide therefore also a protection against germ-containing aerosols. In case you /your son consider wearing a mask to be tolerable in favour of the time limited visit of the tropical house, this provides in any case an increased security compared to an unprotected visit.

Yours sincerely,

Michael Hogardt

Zietz BP, Dunkelberg H, Ebert J, Narbe M. Isolation and characterization of Legionella spp. and Pseudomonas spp. from greenhouse misting systems. J Appl Microbiol. 2006 Jun;100(6):1239-50.
01.08.2011

15.09.2015