CLINICAL MICROBIOLOGY REVIEWS, July 2003, p. 497–516 Vol. 16, No. 3 0893-8512/03/$08.00ϩ0 DOI: 10.1128/CMR.16.3.497–516.2003 Copyright © 2003, American Society for Microbiology. All Rights Reserved. Mycotoxins J. W. Bennett1* and M. Klich2 Department of Cell and Molecular Biology, Tulane University, New Orleans, Louisiana 70118,1 and Agricultural Research Service, Southern Regional Research Center, New Orleans, Louisiana 701242 INTRODUCTION .......................................................................................................................................................497 Mycoses and Mycotoxicoses ..................................................................................................................................497 Definitions, Etymology, and General Principles.................................................................................................498 Toxicology and Human Health .............................................................................................................................499 MAJOR MYCOTOXINS............................................................................................................................................499 Aflatoxins .................................................................................................................................................................499 Downloaded from Citrinin.....................................................................................................................................................................501 Ergot Alkaloids........................................................................................................................................................502 Fumonisins...............................................................................................................................................................503 Ochratoxin ...............................................................................................................................................................504 Patulin ......................................................................................................................................................................505 Trichothecenes.........................................................................................................................................................505 cmr.asm.org Zearalenone .............................................................................................................................................................507 Other Mycotoxins and Purported Mycotoxicoses...............................................................................................508 SPECIAL TOPICS......................................................................................................................................................508 Bioterrorism.............................................................................................................................................................508 Indoor Air Quality and Sick-Building Syndrome...............................................................................................509 at EASTERN REGIONAL RESEARCH CTR on February 3, 2009 FOOD SAFETY AND REGULATION .....................................................................................................................509 SUMMARY ..................................................................................................................................................................510 ACKNOWLEDGMENTS ...........................................................................................................................................511 REFERENCES ............................................................................................................................................................511 INTRODUCTION while others progress to systemic infection. For many mycoses, Mycoses and Mycotoxicoses the ordinary portal of entry is through the pulmonary tract, but direct inoculation through skin contact is not uncommon. Fungi are major plant and insect pathogens, but they are not In contrast to mycoses, mycotoxicoses are examples of “poi- nearly as important as agents of disease in vertebrates, i.e., the soning by natural means” and thus are analogous to the pa- number of medically important fungi is relatively low. Frank thologies caused by exposure to pesticides or heavy metal res- growth of fungi on animal hosts produces the diseases collec- idues. The symptoms of a mycotoxicosis depend on the type of tively called mycoses, while dietary, respiratory, dermal, and mycotoxin; the amount and duration of the exposure; the age, other exposures to toxic fungal metabolites produce the dis- health, and sex of the exposed individual; and many poorly eases collectively called mycotoxicoses. understood synergistic effects involving genetics, dietary status, Mycoses range from merely annoying (e.g., athlete’s foot) to and interactions with other toxic insults. Thus, the severity of life-threatening (e.g., invasive aspergillosis). The fungi that mycotoxin poisoning can be compounded by factors such as cause mycoses can be divided into two categories, primary vitamin deficiency, caloric deprivation, alcohol abuse, and in- pathogens (e.g., Coccidioides immitis and Histoplasma capsu- fectious disease status. In turn, mycotoxicoses can heighten latum) and opportunistic pathogens (e.g., Aspergillus fumigatus vulnerability to microbial diseases, worsen the effects of mal- and Candida albicans). Primary pathogens affect otherwise nutrition, and interact synergistically with other toxins. healthy individuals with normal immune systems. Opportunis- The number of people affected by mycoses and mycotoxico- tic pathogens produce illness by taking advantage of debili- ses is unknown. Although the total number affected is believed tated or immunocompromised hosts. The majority of human to be smaller than the number afflicted with bacterial, proto- mycoses are caused by opportunistic fungi (149, 172, 245, 265). zoan, and viral infections, fungal diseases are nevertheless a The mechanisms of pathogenesis of both primary and oppor- serious international health problem. Mycoses caused by op- tunistic fungi are complex, and medical mycologists have de- portunistic pathogens are largely diseases of the developed voted considerable research energy trying to identify the fac- world, usually occurring in patients whose immune systems tors that distinguish fungal pathogens from saprophytic and have been compromised by advanced medical treatment. My- commensal species (31, 66). Some infections remain localized, cotoxicoses, in contrast, are more common in underdeveloped nations. One of the characteristics shared by mycoses and mycotoxicoses is that neither category of illness is generally * Corresponding author. Mailing address: Department of Cell and communicable from person to person. Molecular Biology, Tulane University, New Orleans, LA 70118. Phone: (504) 788-8101. Fax: (504) 788-8765. E-mail: jbennett@tulane Mycoses are frequently acquired via inhalation of spores .edu. from an environmental reservoir or by unusual growth of a 497 498 BENNETT AND KLICH CLIN.MICROBIOL.REV. commensal species that is normally resident on human skin or Soon, the mycotoxin rubric was extended to include a number the gastrointestinal tract. These commensal species become of previously known fungal toxins (e.g., the ergot alkaloids), pathogenic in the presence of antibacterial, chemotherapeutic, some compounds that had originally been isolated as antibiot- or immunosuppressant drugs, human immunodeficiency virus ics (e.g., patulin), and a number of new secondary metabolites infection, in-dwelling catheters, and other predisposing factors revealed in screens targeted at mycotoxin discovery (e.g., och- (31, 66). The majority of mycotoxicoses, on the other hand, ratoxin A). result from eating contaminated foods. Skin contact with mold- The period between 1960 and 1975 has been termed the infested substrates and inhalation of spore-borne toxins are mycotoxin gold rush (157) because so many scientists joined also important sources of exposure. Except for supportive ther- the well-funded search for these toxigenic agents. Depending apy (e.g., diet, hydration), there are almost no treatments for on the definition used, and recognizing that most fungal toxins mycotoxin exposure, although Fink-Gremmels (80) described occur in families of chemically related metabolites,. some 300 a few methods for veterinary management of mycotoxicoses, to 400 compounds are now recognized as mycotoxins, of which and there is some evidence that some strains of Lactobacillus approximately a dozen groups regularly receive attention as effectively bind dietary mycotoxins (72, 73). Oltipraz, a drug threats to human and animal health (49). Mycotoxicoses are Downloaded from originally used to treat schistosomiasis, has been tested in the animal diseases caused by mycotoxins; mycotoxicology is Chinese populations environmentally exposed to aflatoxin the study of mycotoxins (84). (111). While all mycotoxins are of fungal origin, not all toxic com- In plant pathology, many secondary metabolites produced pounds produced by fungi are called mycotoxins. The target by bacteria and fungi are pathogenicity or virulence factors, and the concentration of the metabolite are both important. i.e., they play a role in causing