Improvement of direct microscopy method for differential diagnosis of skin mycoses

Abstract

Background and Aim.In the practice of veterinary doctors, a number of methods for diagnosing dermatomycoses are used, methods of direct and luminescent microscopy are undeservedly ignored. Сomparative analysis of staining methods for improving the method of direct microscopy, rapid and reliable detection of spores and mycelium in biomaterial, identification of pathogens and differential diagnosis of skin mycoses is of crucial importance for the effective treatment of animals
Materials and Methods. 47 clinical samples of wool and skin taken from farm animals were examined for dermatomycetes. Diagnosis was performed using direct microscopy, fluorescence microscopy with calcofluor, and culture medium culture Saburo.

Results. During the study of 47 samples of biological material, it was found that during microscopy the pathogen was detected in 10 cases (21.3%), during KOH microscopy - in 15 cases (29.9%), during KOH microscopy with other dyes in 11 cases (23.4%), during KOH microscopy with color calcofluor in 25 cases (53.2%). The efficiency of the KOH microscopy method with white calcofluor in comparison with direct microscopy was 60% higher, in comparison with KOH microscopy with other dyes - by 56%, classical KOH microscopy by 43.8%. By the culture method, pathogens were detected in 28 cases (59.6%), of which 7 Trichophyton  spp., 1 Microsporum spp., 14 Aspergillius spp., 6 yeast. Growth was absent in 19 samples (40.4%), bacteria were detected in 3 samples (6.3%). In comparison with  КOH microscopy with calcofluor white, positive results were confirmed in 89.3%.
Conclusion. The use of coloring with various dyes of morphological elements of micromycetes in pure cultures allows you to identify mycelial hyphae of various thicknesses, spores, conidia, other morphological structures and carry out a quick preliminary identification of dermatomycetes and opportunistic mold fungi in smears.