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POSSIBLE ROLES OF FUNGAL HEMOLYSINS IN SICK BUILDING SYNDROME
Citation:
Vesper, S J. AND M. J. Vesper. POSSIBLE ROLES OF FUNGAL HEMOLYSINS IN SICK BUILDING SYNDROME. Advances in Applied Microbiology. Elsevier Science Ltd, London, Uk, 55:191-213, (2004).
Impact/Purpose:
To understand children's risks from exposure to molds in their environment and to explore risk management options for mitigating those risks.
Description:
The World Health Organization (WHO) definition of SBS includes such symptoms in the occupants as headache, distraction, dizziness, fatigue, watery eyes, runny or blocked or bleeding nose, dry or sore throat and skin irritation. The WHO has set a criterion for a healthy building as "less than 20% of occupants complain" (WHO, 1995). Various chemicals, toxins and microorganisms have been suggested as causes of SBS. In this review, we will focus on exposures to fungi (molds) as causes of SBS, with emphasis on the possible role of proteinaceous fungal hemolysins in SBS.
Identifying and quantifying the great diversity of fungi found indoors had been one of the main limitations to addressing the cause-effect relationship between fungal exposures and SBS. The recent development of quantitative PCR (QPCR) analysis of molds (US. Patent 6,387,652) will dramatically improve fungal speciation and quantification, resulting in a highly standardized process for describing the indoor fungal population. Now that the populations of indoor fungi can be easily described, we need to identify possible causes for SBS associated with fungi. We suggest that fungal hemolysins may play a role in some symptoms observed in SBS.
Hemolysins are molecules that are designated as such because they have the ability to lyse red blood cells (RBCs). In this review, only proteinaceous hemolysins will be discussed, although the authors recognize that non-proteinaceous fungal molecules can have hemolytic effects, e.g. T-2 toxin causes hemolysis of red blood cells (Segal et al., 1983). For this review of fungal hemolysins, the artificial separation of macro-fungi (e. g. mushrooms) and micro-fungi (e.g. filamentous species and yeasts) will be used. Throughout this review, we will compare fungal hemolysins with bacterial hemolysins because bacterial hemolysins have been much more extensively studied and may provide useful insights into the nature and activities of fungal hemolysins.
There are primarily two types of hemolysins designated alpha and beta. Alpha hemolysins cause a partial lysis of the RBCs resulting in a darkening of the media around a colony on sheep's blood agar (SBA). The beta hemolysins produce a complete lysis of the RBCs, resulting in a clearing around the colony growing on SBA.