Everything Old is New Again: Successful Treatment of Cutaneous Exophiala Phaeohyphomycosis in Two Valentini Pufferfish (Canthigaster valentini) Using Mohs’ Paste
IAAAM 2018
Michael W. Hyatt1*
1Adventure Aquarium, Camden, NJ, USA

Abstract

Exophiala spp. are pigmented fungi ubiquitous in the environment. These filamentous black yeasts are opportunistic pathogens in warm- and cold-blooded animals, causing superficial and systemic mycoses.1-3 Phaeohyphomycoses caused by Exophiala spp. are an emerging disease in fish.2-5 Two Valentini pufferfish (Canthigaster valentini) from the same exhibit presented similarly within six weeks of each other, both with a white, cutaneous pustular lesion on their dorsum. Cytologies revealed a thick matt of necrotic cells admixed with septate, branching, parallel-walled fungal hyphae. Fungal culture and molecular identification through DNA sequencing of the Internal Transcribed Spacer and Tubby Bipartite Transcription Factor genes confirmed the isolate as Exophiala aquamarina. Despite in vitro antifungal susceptibility,6 anecdotal clinical experience suggests these fungal infections are highly resistant. Initial treatment with fluconazole prolonged immersion was unsuccessful. Topical therapy using Mohs’ Paste,7-9 a zinc chloride-based chemical fixation treatment from the 1930s and 1940s, was successful. Once applied, the superficial tissues are infiltrated and preserved, ultimately sloughing two weeks later. To hasten tissue healing of the exposed muscle and dermis, a POLYOX mucosal bioadhesive powder compounded with 0.0024% misoprostol, 2% phenytoin, and 2% enrofloxacin was applied topically every three days. Complete healing with epithelialization and pigmentation was achieved in 74 and 80 days with no evidence of recurrence. These cases provide evidence for a successful treatment option of a highly resistant fungal pathogen.

Acknowledgements

The author thanks the Adventure Aquarium Fish and Invertebrate husbandry team for their dedicated care of these fish and their assistance with treatments. The author also thanks the University of Connecticut’s Veterinary Medical Diagnostic Laboratory and University of Texas San Antonio’s Fungal Testing Laboratory for fungal culture and molecular identification.

* Presenting author

Literature Cited

1.  de Hoog GS, Vicente VA, Najafzadeh MJ, Harrak MJ, Badali H. 2011. Waterborne Exophiala species causing disease in cold-blooded animals. Persoonia. 27:46–72.

2.  Kurata O, Munchan C, Wada S, Hatai K, Miyoshi Y, Fukuda Y. 2008. Novel Exophiala infection involving ulcerative skin lesions in Japanese flounder Paralichthys olivaceus. Fish Pathol. 43:35–44.

3.  Overy DP, Groman D, Giles J, Duffy S, Rommens M, Johnson G. 2015. Exophiala angulospora causes systemic mycosis in Atlantic halibut: a case report. J Aquat Anim Health. 27(1):12–19.

4.  Camus A, Berliner A, Hyatt M, Hatcher N, Clauss T. 2015. Exophiala xenobiotica aerocystitis in a Queensland grouper Epinephelus lanceolatus (Bloch). J Fish Dis. 38:221–225.

5.  Nyaoke A, Weber ES, Innis C, Stremme D, Dowd C, Hinckley L, Gorton T, Wickes B, Sutton D, de Hoog S, Frasca Jr. S. 2009. Disseminated phaeohyphomycosis in weedy seadragons (Phyllopteryx taeniolatus) and leafy seadragons (Phycodurus eques) caused by species of Exophiala, including a novel species. J Vet Diagn Invest. 21:69–79.

6.  Najafzadeh MJ, Saradeghi Keisari M, Vicente VA, Feng P, Shamsian SAA, Rezaei-Matehkolaei A, de Hoog GS, Curfs-Breuker I, Meis JF. 2013. In vitro activity of 8 antifungal drugs against 106 waterborne and cutaneous Exophiala species. Antimicrob Agents Chemother. 57:6395–6398.

7.  Kakimoto M, Tokita H, Okaura T, Yoshino K. 2010. A chemical hemostatic technique for bleeding from malignant wounds. J Palliat Med. 13(1):11–13.

8.  Mohs FE, Sevringhaus EL, Schmidt ER. 1941. Conservative amputation of gangrenous parts by chemosurgery. Ann Surg. 114:274–282.

9.  Trost LB, Bailin PL. 2011. History of Mohs surgery. Dermatol Clin. 29:135–139.

 

Speaker Information
(click the speaker's name to view other papers and abstracts submitted by this speaker)

Michael W. Hyatt
Adventure Aquarium
Camden, NJ, USA


MAIN : Fish 2 : Treatment of Cutaneous Exophiala Phaeohyphomycosis
Powered By VIN
SAID=27