Perhaps I can add a bit of a different perspective here.
I'm a bit of a nerd in my spare time with chameleons being just one of my other unusual hobbies is
mycology
First.
BOTH bacteria and different fungus are a normal and healthy part of any soil medium.
believe it or not, they can provide a great service in keeping the plant healthy.
Problems tend to occur when there is a imbalance as the result
of over watering, poor drainage too rich of soil etc.
While I can understand that you don't want your pet to consume any fruiting fungus
There is a fairly common species of "golden yellow" fungus that sets up shop
in many composting operations. They're not especially harmful or dangerous
according to some of the reference books depending on the species they *may* even be edible (don't try that!).
I would be more concerned about the thousands of spores that they're producing
and being breathed in your animals lungs).
While some are completely benign others can infect the lungs and cause problems in your pet.
(commercially grown oyster mushrooms are known for this in the workers).
You can't remove the problem just by changing the soil... only delay it.
you only need one cell from the fungal network to start the process again.
It's a sure bet that whatever you've got, it integrated into the plants roots.
Nuking the soil will only cause more problems by removing
all the competition for whatever survives.
If you're concerned about the fruitings then the first thing I would do is tone down the watering.
changing the soil to something less rich and woody will also help
(add perlite and sand to a 1/3 standard potting soil).
Lastly, I would introduce a healthy competitive micoflora into the soil (use fire vs fire)
that will prevent the domination of a single species within the pot and lower
it's capability to gather the required energy reserve to produce fruits
or it'll kill the other culture entirely.
you can do that by buying one of the general
Dr Earth Plant Food products
The brand shouldn't be too difficult to find.
It contains SAFE strains of soil building microbes
as well as ecto & endo mycorrhizae
those will not only help the plant
they're break down random droppings and dead feeders cleanly
As well as, keep harmful fungus out of your soil from the outside.
I had the same problem with two of the pots in my hatchling setups.
A nice watering with the dr. earth solved it right away...
I use the bloom booster (#8) and the fruit and veggie product on a rotation (#5) with all the cage plants.
enjoy.