Nannizziopsis guarroi, a keratinophilic fungus, is an important cause of dermatomycosis in companion lizards. At this time effective disinfection protocols are unknown and additional information is needed to prevent contamination of surfaces and equipment used in the care of these animals. To this aim, the qualitative in vitro disinfecting capability of eight commonly used household and laboratory disinfectants (Novalsan®, 3% and 10% dilutions of commercial bleach, Virkon®-S, Lysol® household cleaner with hydrogen peroxide, 70% ethanol, 409® and household cleaning ammonia) were tested at two different contact times (two and ten minutes) with three different aqueous fungal concentrations of four molecularly confirmed N. guarroi isolates. A positive control after contact with saline was also grown. After contact with disinfectant or saline, the isolates were incubated, and photographic images were taken of plate growth on day 10. Images of each plate were scored using a semiquantitative scoring system. The only disinfectant that completely inhibited growth for all four isolates at both contact times and at all three isolate dilutions was 10% dilution of commercial bleach. All four isolates grew after contact with ammonia, regardless of contact time or isolate dilution and the other disinfectants showed variable inhibition of growth that was either isolate or concentration dependent or both. In conclusion, a minimum of two-minute exposure to 10% dilution of commercial bleach is recommended for disinfection of surfaces and instruments contaminated with N. guarroi.
Nannizziopsis guarroi infection in lizards presents therapeutic challenges as reports of poor clinical outcomes, including antifungal toxicity, incomplete clearance of infection and recrudescence of infection are common. The case presented here describes the successful treatment of a N. guarroi infection using systemic terbinafine and environmental disinfection in a captive-bred central bearded dragon (Pogona vitticeps). The lizard presented with darkly colored cutaneous lesions and mycologic culture samples were identified as N. guarroi using Matrix-Assisted Laser Desorption/Ionization – Time Of Flight (MALDI-TOF). Based upon the lack of clinical resolution of cutaneous lesions, weight loss, and reduced appetite, initial treatment with voriconazole was discontinued. Terbinafine was prescribed and weekly environmental disinfection with sodium hypochlorite was initiated until cutaneous clearance of the fungus was confirmed by negative culture, histopathology, and N. guarroi qPCR from cutaneous swab. Terbinafine treatment was discontinued after 80 days. There were no clinical signs of toxicity associated with the prolonged treatment and the lizard has not developed any cutaneous lesions or illness in more than two years of clinical follow up. While the most ideal treatment of N. guarroi is still being investigated, this case demonstrates a promising and safe treatment option for an increasingly common and devastating disease.
OBJECTIVE To determine the environmental persistence of Nannizziopsis guarroi on clinically relevant solid and aqueous substrates. SAMPLE 2 molecularly confirmed isolates of N guarroi obtained from clinical cases of dermatomycosis in bearded dragons (Pogona vitticeps). PROCEDURES 3 concentrations (1 McFarland, 1:10 McFarland, and 1:100 McFarland) of fungal suspension were exposed to 7 sterilized solid substrates (fabric aquarium liner, wood mulch, sand, hard plastic, glass, cotton, and stainless steel) and 2 sterilized aqueous substrates (distilled water, saline solution [0.9% NaCl]). Biological replicates were performed for the contamination of the solid substrates. On days 1, 3, and 14 after contamination, the substrates were sampled for fungal culture with technical repeat. Fungal cultures were incubated at room temperature for 10 days and then evaluated for fungal growth. RESULTS Data from wood mulch were not evaluated because of plate contamination. Overall, the ability to culture N guarroi from solid substrates was isolate, time, and fungal concentration dependent. Viable fungus was isolated from fabric aquarium liner and glass on day 1 and days 1 and 3, respectively. N guarroi was cultured from all other solid substrates at day 14 from at least 1 isolate and/or fungal concentration. Viable N guarroi was isolated from both aqueous substrates at day 14, regardless of isolate or fungal concentration. CLINICAL RELEVANCE The environmental persistence of N guarroi should be considered when treating lizards infected with this fungus. Fomites may contribute to the contagious nature of this pathogen and environmental disinfection should be performed to reduce transmission.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.