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The iron-hydrogen peroxide-iodide system is fungicidal: activity against the yeast phase of Blastomyces dermatitidis
Abstract:
A series of experiments show the potency of a newly described microbicidal system, involving iron, H2O2, and halide, in killing a fungus (Blastomyces dermatitidis). B dermatitidis has previously been shown susceptible to the myeloperoxidase-H2O2-halide system. The present studies show killing of either of two strains in 1 hour if Fe++ at 5 X 10(-5)M, H2O2 at 5 X 10(-5)M and Kl at 5 X 10(-4)M are all present (P less than 0.001). EDTA, a Fe++ chelator, abrogates killing. The mechanism presumably utilizes hydroxyl radical, since an inhibitor, ethanol, also neutralizes the system. The bactericidal and fungicidal system is of great potential importance in vivo.
Insights
This study demonstrates a novel microbicidal system using iron, hydrogen peroxide (H2O2), and halide to effectively kill Blastomyces dermatitidis fungus. The system
Area of Science:
- Microbiology
- Biochemistry
- Mycology
Background:
- Blastomyces dermatitidis is a fungus causing blastomycosis.
- The myeloperoxidase-hydrogen peroxide-halide system is known to be microbicidal.
- Previous research indicated B. dermatitidis susceptibility to this system.
Purpose of the Study:
- To evaluate a newly described microbicidal system involving iron, H2O2, and halide against Blastomyces dermatitidis.
- To elucidate the mechanism of action of this iron-halide-H2O2 system.
Main Methods:
- In vitro experiments were conducted using two strains of B. dermatitidis.
- The microbicidal activity was assessed by exposing the fungus to specific concentrations of Fe++, H2O2, and KI.
- The role of iron was investigated using EDTA, a chelator.
- The mechanism was probed using ethanol as a hydroxyl radical inhibitor.
Main Results:
- Complete killing of B. dermatitidis strains was observed within 1 hour when Fe++ (5 X 10(-5)M), H2O2 (5 X 10(-5)M), and KI (5 X 10(-4)M) were combined (P < 0.001).
- EDTA abrogated the microbicidal effect, indicating the essential role of Fe++.
- Ethanol neutralized the system, suggesting hydroxyl radical involvement.
Conclusions:
- The iron-halide-H2O2 system is a potent microbicide against Blastomyces dermatitidis.
- The mechanism likely involves hydroxyl radical generation.
- This system holds significant potential for in vivo applications due to its bactericidal and fungicidal properties.