Source of allergins in Type I Hypersensitivity

[Christ Skory]

My ignorance on this topic may well be a result of me being a 
microbiologist and not an immunologist.  But, I am very curious 
why only yeasts and molds tend to be the only microorganisms 
accused of causing a Type I hypersensitivity (ie asthma, 
hayfever, food allergy) reaction.  I have never heard of 
bacterial organisms causing this effect even though they are 
probably inhaled and definitely ingested just as much as yeasts 
and molds.   Does anybody have any idea about this or could you 
point in the right direction to find the answer?

Thanks

Christopher D. Skory, Ph.D. 		 
Research Microbiologist

National Center for Agricultural	        
  Utilization Research, USDA-ARS 	             
Fermentation Biochemistry Unit 
Peoria, Illinois 61571-3902       

E-mail:  skorycd at ncaur1.ncaur.gov