Can anyone identify this Ecuadorian mushroom?

The stipe is about 7 mm diameter and the cap roughly 7 cm. It is initially white and dry on the outside. It looks and smells very much like a supermarket Agaricus mushroom, except it has a wider and thinner cap and a longer and thinner stipe.

It was found sprouting from woven polypropylene sacks full of human feces (plus a mix of sawdust and wood ash that was added to cover the fresh feces). These sacks were filled in Urine-diverting Dry Toilets in Puyo, Ecuador (900 meters elevation, on the edge between Amazonia and the Andes). These were stored for over 2 years, protected from rain, but on the soil and thus absorbing some humidity from it via capillary action. More info on these ecologically friendly toilets on my blog, http://www.inodoroseco.blogspot.com/. Also www.ecosanres.org and www.susana.org. Switching to UDDTs is likely one of the easiest ways to reduce one´s ecological and carbon footprint.

Is this species known to be associated with feces? Or is it mainly digesting the sawdust?
Could it be destroying Ascaris helminth eggs, other pathogens, etc.?

Thanks.

Best wishes,
Chris Canaday, canaday2@gmail.com