Yes, the clouds are home to tons of lifeforms, especially bacteria. They are small and easy to carry in the air. Clouds are a good home for dust particles, dust mites, bacteria and who knows what else. There a whole jungle in there!
Bacteria was found even at 40 km high up, in the air, above every possible terrain you can think of. The bacteria are also living and multiplying in the cloud where they help forming rain drops, snowflakes, hail.
The bacteria from up there live due to the fact that they eat sugars flown up by the wind. These sugars are generated by plants on earth.