Antifungal Properties of Cutaneous Bacteria Found on Rana catesbeiana (North American Bullfrog) and Bufo boreas halophilus (California Toad). Kathy Szick-Miranda California State University, Bakersfield www.grit.com/animals/wildlife/american- bullfrog.aspx 2010
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Antifungal Properties of Cutaneous Bacteria Found on Rana catesbeiana (North American Bullfrog) and Bufo boreas halophilus (California Toad). Kathy Szick-Miranda.
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Antifungal Properties of Cutaneous Bacteria Found on Rana catesbeiana (North American Bullfrog) and Bufo boreas halophilus (California Toad).
Kathy Szick-MirandaCalifornia State University, Bakersfield
Marsh and Selwyn 1977; Al-Admawy and Noble 1981; McFall-Ngai et al. 2005
Cutaneous bacteria of some amphibians produce antibiotics that protect their hosts from pathogenic fungi.
Austin 2000; Brucker et al. 2008a, 2008b; Harris et al. 2009
Introduction
Hypothesis:Bullfrogs and California Toads possess cutaneous bacteria that will inhibit the growth of some fungi.
Catch frogs and toads
Streak plate
Purify cutaneous bacterial isolates
Methods
Rinse with sterile water
Swab frogs/toads
DNA extraction from fungi
PCR amplification
DNA sequencing to identify fungi
Methods/Results
Five fungi identified:
2 distinct Aspergillus sp.
Cochlibolus spEupenicillium sp.Galactomyces
geotrichum
Plate water samples
Purify fungal isolates
Collect water from frog/toad environment
Methods
Cutaneous bacteria challenged against environmental fungi
Results233 pure bacterial isolates challenged against 5 environmental fungi
5 isolates were positive against 4 fungi5 isolates were positive against 3 fungi16 isolates were positive against 2 fungi43 isolates were positive against 1 fungus
Additional results:
Cochlibolus sp. inhibited by 87% of the positive isolates.Eupenicillium sp. inhibited by 20% of the positive isolates.Aspergillus sp. (a) inhibited by 20% of the positive isolates.Galatomyces geotrichum inhibited by 22% of the positive
isolatesAspergillus sp. (b) inhibited by 9% of the positive isolates.
Question
Hypothesis #2: Bullfrogs and California Toads possess cutaneous bacteria that will inhibit the growth of known amphibian and human pathogens.
Data support the original hypothesis.
Challenge positive isolates against known pathogens
Approach:
Pathogens• Basidiobolus ranarum: • known human and amphibian pathogen• causes skin and GI lesions • found worldwide
• Candida albicans: • normally found in low levels in the human body• causes yeast infections