P503 Molecular epidemiology of Trichophyton mediated infections among canines from Northern India

Abstract

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PM ObjectivesDermatophytes are keratinophilic fungi that cause skin infections among animals and humans. Recently, the incidence rates of fungal infections especially due to the Trichophyton spp. are being considered as endemic in many geographical locations. The cause of recent surge of dermatophytosis due to this agent in humans is not known. It is assumed that pets may be one of the sources which are not established till now. The present study was conducted to understand the molecular heterogeneity of Trichophyton spp. of canines and felines, and their phylogenetic relationship with human isolates.MethodsThe samples (skin scrapings) were collected from 386 canines and 56 felines exhibiting clinical signs of ringworm during the period of 2020-2021 from the veterinary hospitals and farms in the states of Uttar Pradesh and Kerala, India. All the samples were attempted for isolation on Sabouraud's dextrose agar (with chloramphenicol and cycloheximide at 0.05 and 0.5 g/l, respectively). The antifungal susceptibility assay was performed by following the Clinical and Laboratory Standards Institute (CLSI) guidelines, document M38-Ed3 for filamentous fungi (CLSI: Wayne, PA, USA, 2017). The isolates presumptively identified as Trichohypton spp. were characterized further based on PCR and sequencing of three genetic markers such as ITS, Tef1-α, and beta-tubulin genes. Phylogenetic analysis and taxonomical determination of the Trichophyton isolates were performed. Three human isolates of T. mentagrophytes were used for comparative study.ResultsA total of 67 (15.16%, 67/442) samples revealed the presence of fungal hyphae on direct microscopic examination. On culturing, 52 samples were found to be positive for dermatophytes. Among these, 10 isolates were presumptively identified as T. mentagrophyte spp. based on morphological and microscopic examinations. Most of the strains were sensitive to all drugs tested except fluconazole, which showed a resistance pattern for most strains. Based on sequence homology and phylogenetic inferences, the Trichophyton isolates belonged to four different species/genotypes, such as T. mentagrophytes genotype VIII (5), T. interdigitale (2), T. simmi (2), and T. quinckeanum (1). Human isolates were represented as T. mentagrophytes genotype VIII (2) and T. benhamie (1).ConclusionTo conclude, the study reports for the first time the prevalence, species diversity, and antifungal resistance among Trichophyton spp. from canines in India. Even though the Trichophyton prevalence was lower in canines, the presence of T. mentagrophytes genotype VIII/T. indotineae is of great public health significance. This indicates the zoonotic sharing of strains especially T. mentagrophytes gentotype VIII in both hosts that are also considered as the recently endemic pathogenic clone in India.