Cottons collected from various countries and various parts of the United States are associated with a small and constantly present group of gram negative bacilli. This implies the presence of a rather specific ecological niche for this symbiotic relationship.

The same group of microorganisms are found on cotton plant parts harvested in the fields and in the air of cotton mills.

Although occasionally other organisms may be found in the air of the mills, the major source of the gram negative microorganisms is the cotton being processed. This is confirmed by data from mills processing polyester.