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Fungi associated with drug recalls and rare disease outbreaks
Donald G Ahearn1, R Doyle Stulting
1Biology Department (D.G.A.), Georgia State University, Atlanta, 30303, GA, dgahearn@gsu.edu.
Abstract:
Fungi rarely cause disease outbreaks associated with use of microbe-contaminated drugs. These rare episodes typically involve a restricted spectrum of common environmental species with relatively low virulence, rather than classical pathogens. Review of data involving over-the-counter contact lens solutions and prescription drug-related recalls revealed six episodes during the past decade with significant adverse health and financial impact (including loss of vision and death). Contaminations involved fungi mostly identified with the genera Aspergillus, Exserohilum, Fusarium, Paecilomyces, and Rhizopus. These organisms are noted for their capacity to produce resistant morphotypes (chlamydoconidia, ascospores) under various adverse conditions, generally with temperature survival/tolerances markedly in excess of maximal growth temperatures. High constituent levels of melanin, trehalose and heat-shock proteins facilitate differential survival of morphotypes following exposures to toxic chemicals and temperatures above 80 °C. Adverse environmental factors that induce resistant morphotypes are suggested to occur more readily in situ than during in vitro testing. Rare unexplained, sporadic drug contamination episodes with select thermotolerant fungi may relate, in part, to resistant dormant stages.
Insights
Rare fungal contaminations in drugs, like contact lens solutions, can cause severe illness and death. Thermotolerant fungi with resistant stages, such as Aspergillus and Fusarium, are often implicated in these outbreaks.
Area of Science:
- Mycology
- Pharmaceutical Microbiology
- Public Health
Background:
- Fungal contamination in pharmaceutical products is rare but can lead to severe health consequences.
- Outbreaks typically involve environmental fungi with low virulence, not classical pathogens.
- Recent recalls highlight significant adverse events, including vision loss and fatalities.
Purpose of the Study:
- To investigate the characteristics of fungi involved in rare but impactful drug contamination outbreaks.
- To understand the mechanisms contributing to fungal survival in pharmaceutical products.
- To identify factors contributing to unexplained fungal contamination events.
Main Methods:
- Review of drug recalls and adverse event data over the past decade.
- Identification of fungal genera associated with contamination episodes.
- Analysis of fungal properties related to survival under stress conditions.
Main Results:
- Six major contamination episodes were identified, involving contact lens solutions and prescription drugs.
- Commonly implicated fungal genera include Aspergillus, Exserohilum, Fusarium, Paecilomyces, and Rhizopus.
- These fungi possess resistant morphotypes (chlamydoconidia, ascospores) and high tolerance to heat (>80°C) and chemicals, facilitated by melanin and trehalose.
Conclusions:
- Thermotolerant fungi with resistant stages are implicated in rare, severe drug contamination outbreaks.
- In situ environmental factors may more readily induce resistant fungal morphotypes than in vitro conditions.
- Understanding these fungal traits is crucial for preventing future pharmaceutical contamination events.
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