[refurb]

Bacteria can mutate quite quickly and wipe out an entire species pretty fast, reducing biodiversity.

[saagarjha]

Can they wipe out thousands of species?

[frutiger]

Yes: https://en.m.wikipedia.org/wiki/Great_Oxidation_Event

[MiyamotoAkira]

Wait, that says it took around 0.3 billion years, and when there was only single cell life, we have no clue about the biodiversity at that point in time. It cannot compare in time scale, and we have no clue if it can compare on biodiversity scale.