Aspergillus species growing in humans form mycotoxins

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from USDA (Department of Agriculture) website:

Research Project: Aflatoxin Control Through Targeting Mechanisms Governing

Aflatoxin Biosynthesis in Corn and Cottonseed

Location: Food and Feed Safety Research

Title: Aflatoxin and Ochratoxin Production by Aspergillus Species under ex vivo

Conditions

Authors

Klich, Maren

Tang,

Denning, - WYTHENSHAWE HOSPITAL

Submitted to: Mycopathologia

Publication Type: Peer Reviewed Journal

Publication Acceptance Date: May 21, 2009

Publication Date: N/A

Interpretive Summary: Many molds produce poisons that are harmful to humans and

animals (mycotoxins). A disease caused by members of the mold genus Aspergillus,

called aspergillosis, is increasing in frequency and is often fatal in patients

with poor immune systems. In this paper we investigate whether or not it would

be possible for Aspergillus species growing in humans to form mycotoxins. This

is important because toxins could be increasing the virulence of the disease. We

grew molds under conditions mimicking those in human bodies. We found that one

toxin, aflatoxin, is unlikely to form in human tissue, but that another toxin,

ochratoxin, could potentially form in humans with aspergillosis.

Technical Abstract: Aspergillus species are increasingly important human

pathogens. It is not known whether toxic metabolites of many of these pathogenic

species can act as virulence factors in aspergillosis. We examined isolates of

aflatoxin and ochratoxin-producing species for toxin production in `near human¿

conditions. Seven of the 21 aflatoxin-producing isolates screened produced

aflatoxin at 35o and 37o C on the general medium Yeast Extract Sucrose agar

(YES). However, none of them produced toxin at these temperatures on Brain Heart

Infusion agar (BHA), a medium that mimics human tissue, or on BHA with modified

pH or sugar levels. Six of the 12 ochratoxin-producing isolates examined

produced toxin at 35o C on YES. All three isolates of A. alliaceus produced

ochratoxin on BHA or modified BHA at 37o C. One strain of A pseudoelegans

produced a minute amount of ochratoxin on modified BHA at 37o C. These data

indicate that aflatoxin is an unlikely virulence factor but that ochratoxin may

be a potential virulence factor in aspergillosis.

Last Modified: 09/28/2009

http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=236033