P071 Isolate profiling and antifungal susceptibility determination for terbinafine and itraconazole among dermatophytes in a tertiary care hospital of western rajasthan

Abstract

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PM ObjectiveTo determine the species distribution of causative agents causing dermatophytosis, and their antifungal susceptibility pattern for terbinafine and itraconazole in trichophyton spp among samples collected in patients with dermatophytosis clinical suspicion during the period of December 1, 2020 to January 31, 2022.Materials and MethodsThis is a prospective study conducted in the Department of Microbiology of a tertiary care super specialty and referral Centre of western Rajasthan from December 1, 2020 to January 31, 2022.Skin scraping, nail clipping, and hair pluckings were collected in mycology lab from clinically suspected cases of dermatophytosis presenting to the department of dermatology for conventional identification, and antifungal susceptibility testing.The specimens were subjected to direct KOH and calcofluor white microscopy and conventional fungal culture on SDA at 25 ͦ C and 37 ͦ C.The cultures positive for dermatophytes were speciated by microslide culture lactophenol cotton blue mount, hair perforation test, and urease test.The isolates identified as Trichophyton spp were taken up for antifungal susceptibility testing against terbinafine and itraconazole by microbroth dilution according to CLSI-M38 A2 guidelines. Further terbinafine resistance gene evaluation for detection of C1191A and T1189C single nucleotide polymorphism in Squalene epoxide by Amplified Refractory Mutation System-Polymerase chain Reaction (ARMS-PCR) is undergoing for trichophyton spp.ResultsOver the 14-month study period, the laboratory processed total of 174 specimens: 134 skin scraping, 36 nail clipping, and 4 hair pluckings. Of them, 106 (61.62%) specimens were microscopy positive and 111 (63.79%) were culture positive. Out of the 111 culture-positive agents isolated, 94 (84.68%) were found to be dermatophytes. On isolate profiling of 94 dermatophytes T. mentagrophyte was found to be most common 45 (48%) followed by T. rubrum 27 (29%), T. tonsurans 20 (21%), T. verrucosum 1 (1.1%), and Microsporum spp 1(1.1%). Antifungal susceptibility of 93 Trichophyton spp against terbinafine showed resistance among 58.06% isolates with 83.33% isolates among terbinafine resistant cases showing ≥4 μg/ml minimum inhibitory concentration. There was no resistance detected for itraconazole with microbroth dilution.ConclusionA total of (54.02%) skin, hair, nail infections were found to be caused by dermatophytes.On isolate profiling, T. mentagrophyte, T. rubrum, and T. tonsurans were found to be predominant species among our isolates showing altered trend of local isolates from T. tonsurans being second most common spp isolated in past.On antifungal susceptibility >55% isolates showed resistance for Terbinafine with >80% having higher MIC of ≥4 μg/ml on the contrary there was no observed resistance for itraconazole.There is a need for encouraging dermatologists for prescribing routine fungal microscopy, culture, and AFST for dermatophytes in Western Rajasthan, to reduce the indiscriminate use of antifungals.