Microbial allergy/hypersensitivity

Fungal allergens have long been known. However, in recent years, non-fungal microbial allergens are increasingly being found[163,164]. A common bacterial plant pathogen, Pantoea agglomerans causes human respiratory diseases such as asthma and HP[165]. Farm environments have Archaea[166] that are capable of causing immune reactions[167]. IgE-mediated responses to viruses (i.e., HIV[94], varicella zoster[168,169], influenza virus[170] and parvovirus[171]) are also being found.
In Bachert et al’s[172] review of chronic rhinosinusitis (CRS), the concept of bacterial allergy and colonization was one component of their proposed immune barrier hypothesis. Calenoff et al[173] found an elevated level of bacterial allergy in CRS.
Microbial allergies are potentially increased by exposure to damp environments due to increased fungi and bacteria. Damp environments have been associated with the development or exacerbation of a range of respiratory diseases, such as asthma, hypersensitivity pneumonitis, allergic rhinitis and chronic rhinosinusitis[174].
Although dampness has been associated with increased disease rates, Mendell et al[174] found no clear relationships between disease features and measured microbial exposures. The PHM hypothesis suggests that low abundance PHMs would increase in damp environments and might be an important missing factor.
Researchers have noted inadequate research on bacteria in damp buildings[175,176]. Mycobacteria can cause greater immune responses and be just as serious a threat as molds[176]. A study of showerhead microbial biofilms found high levels of non tuberculous mycobacteria and other potential pathogens[177].