Dermatophytosis: fluorostaining enhances speed and sensitivity in direct microscopy of skin, nail and hair specimens from dermatology outpatients

Abstract

Direct microscopy of keratinised specimens is a standard screening procedure that assists clinicians to differentiate true superficial mycoses from non-fungal disorders of the skin, nail and hair. Most clinical dermatologists use bright-field microscopy when searching for dermatophyte fungi in clinical samples while laboratory-based mycologists increasingly favour fluorescence microscopy in order to optimise visualisation of fungal elements. This study compared the validity and speediness of fluorescence microscopy vs. conventional light microscopy when screening for fungi in 206 dermatological samples from dermatology outpatients. Both senior dermatologist and a less experienced investigator (medical student) attained high and comparable levels of specificity (91.7-93.8%), positive predictive value (77.1-81.4%) and negative predictive value (83.7-89.9%) using either method. Fluorostaining with Blankophor prior to fluorescence microscopy increased the sensitivity by 22 ± 1% as compared to light microscopy of unstained samples. For both investigators, the time required to identify fungal elements by the fluorescence-based technique was reduced by at least 50%, thus improving the performance of direct microscopy in the clinical setting.

Infection of Trichophyton verrucosum in cattle breeders, Poland: A 40‐year retrospective study on the genomic variability of strains

“…This requires search for rapid and reliable methods for routine diagnostics. These methods should be handy, sensitive and time‐ and money‐saving screening tools . Molecular methods offer an opportunity to confront the lack of confidence in mycological diagnosis based on only phenotypic biological confirmation with a relatively high discriminatory power and good reproducibility of results .…”

“…These methods should be handy, sensitive and time-and money-saving screening tools. 47,48 Molecular methods offer an opportunity to confront the lack of confidence in mycological diagnosis based on only phenotypic biological confirmation with a relatively high discriminatory power and good reproducibility of results. 10,38,49 Nowadays, in studies conducted in some countries, for instance in France, T. verrucosum strains are identified without using any molecular techniques.…”

Evaluation of growth conditions and DNA extraction techniques used in the molecular analysis of dermatophytes

“…It requires search for rapid and reliable methods for routine diagnostics. These methods should be handy, sensitive and time-saving screening tools useful for both senior staff and novices at dermatological office settings (Ovren et al 2016;Bosshard 2011;Labarca et al 1998;Liu et al 2000a,b). Molecular methods, such as PCR fingerprinting and others, offer an opportunity to confront the lack of confidence in mycological diagnosis based on only phenotypic biological confirmation with a relatively high discriminatory power and good reproducibility of results obtained in 1-day workflow (Deuter et al 1995;Nenoff et al 2007;Leibner-Ciszak et al 2010;Petinataud et al 2016).…”

“…; Ovren et al . ). Accurate identification of dermatophyte species is important both for epidemiological studies and for implementing antifungal treatment strategies (Didehdar et al .…”

“…The diagnosis of superficial mycoses relies on a combination of clinical features and mycological identification of pathogenic fungi in dermatological specimens (Lasseter et al 2011;Ovren et al 2016). Accurate identification of dermatophyte species is important both for epidemiological studies and for implementing antifungal treatment strategies (Didehdar et al 2016).…”