I know absolutely nothing about this organism, but unless you ingest some of your shower water, woul you not be OK?
If this is not the case, I would resort to solar showers filled with boiled water. Thee can be had in varying capacities up to five gallons. long and tedious of course, but you can get squeaky clan. I have used solar showers for up to two weeks while on field excavations (you get mighty dirty on those!)
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Geezer in Chief