Rapid detection of fungal feet infection by LED-UV light

Author:

Ester Fusté 1, Guadalupe Jimenez Galisteo 2, M. Jesus Sanchez 3, Mercedes Aguilar 4, Teresa Vinuesa* 2

Author address:

1 University of Barcelona, Microbiology Unit/Dep Nursery, Public Health and Mental Health/IDIBELL, Hospitalet de llobregat,
Spain; 2 University of Barcelona, Microbiology Unit/Dep Pathology and Experimental Therapeutics/IDIBELL, Hospitalet de llobregat, Spain; 3
Centre Medic Creu Blava, Podiatrics Unit, Esparraguera, Spain; 4
Hospital Universitari Bellvitge, ICS/ IDIBELL, Hospitalet de llobregat, Spain

Full conference title:

European Congress of Clinical Microbiology and Infectious Diseases 2020

Date: 24 June 2020

Abstract:

Background: Fungal feet infections are usually torpid diseases whose specific diagnostic is compulsory as similar clinical entities are treated with steroids that can worsen the mycotic infection. To avoid inaccurate therapies, a fast and accurate detection of fungi is needed. Potassium hydroxide (KOH) treatment of samples is used for clarifying specimens (rich in keratin), before examination by bright light microscopy but it requires skilled observers. Fluorescent brighteners absorbing UV light and emitting blue light, with affinities for polysaccharides with β-links, have been used to facilitate observation. Our group uses for this purpose Leucophor®, a disulphonated stilbene brightener along with KOH treatment. Based on the report of Denny G et al referent to hand held UV illumination, we aimed to evaluate an alternative easy to use, none-expensive method to fasten the time elapsed between the clinical suspicion and the confirmation of the presence of a fungal infection. We examined patients with clinical suspicion of mycotic infection as well as nail or skin samples, by means of a hand held LED UV, comparing it with the visualization by a fluorescence microscopy.

Materials/methods: 40 patients with clinical suspicion of fungal feet infection and 40 healthy individuals were analyzed in vivo by both methods. Their collected specimens were KOH digested, Leucophor® stained and examined in a fluorescence microscopy (Nikon E800). After switching the UV source off, they were observed under tangential illumination from a hand-held LED UV Flashlight (HAN-WY6975*4) at 395 nm. Also a 1418 90X Phone LED UV Light Magnifier 90 x and 60 X adapted to a Smart Phone Huawei with a Leica Camera was used. Culture in appropriate media was performed in all cases. Moreover, a series of 30 nails and scrapings of our collection were examined and imaged (15 positive: Aspergillus sp., Trichophyton rubrum, Scopulariopsis sp.and 15 culture negative).

Results: Even that the brightness of the conidia and hyphae using the hand-held LED UV Flashlight diminished slightly, it appears still clear permitting an accurate diagnosis of the presence of fungi.

Conclusions: The use of low cost devices seems feasible for detection of fluorescence from samples containing fungi with reasonable resolution.

Presenter email address: tvinuesa@ub.edu

Abstract Number: 1317

Link to conference website:

Link Conference abstract: 

ECCMID 2020

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