Complementary role of a polymerase chain reaction test in the diagnosis of onychomycosis

Chandran, Nisha Suyien; Pan, Jiun-Yit; Pramono, Zacharias Aloysius Dwi; Tan, Hiok‐Hee; Seow, Chew-Swee

doi:10.1111/ajd.12027

Cited by 19 publications

(14 citation statements)

References 16 publications

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“…The main drawback of culture remains the slow growth of dermatophytes, delaying the results by up to 6 weeks in the event of supplementary tests to enhance frequent weak sporulation . Mycological culture is highly specific, but negative results associated with a positive microscopic direct examination are found in up to 40% of cases, impeding its sensitivity . In our study, the different LCA models resulted in a 100% specificity for culture.…”

Section: Discussionmentioning

confidence: 63%

Optimising the diagnostic strategy for onychomycosis from sample collection to FUNGAL identification evaluation of a diagnostic kit for real‐time PCR

Petinataud

Berger

Ferdynus

et al. 2016

Mycoses

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Onychomycosis is a common nail disorder mainly due to dermatophytes for which the conventional diagnosis requires direct microscopic observation and culture of a biological sample. Nevertheless, antifungal treatments are commonly prescribed without a mycological examination having been performed, partly because of the slow growth of dermatophytes. Therefore, molecular biology has been applied to this pathology, to support a quick and accurate distinction between onychomycosis and other nail damage. Commercial kits are now available from several companies for improving traditional microbiological diagnosis. In this paper, we present the first evaluation of the real-time PCR kit marketed by Bio Evolution for the diagnosis of dermatophytosis. Secondly, we compare the efficacy of the kit on optimal and non-optimal samples. This study was conducted on 180 nails samples, processed by conventional methods and retrospectively analysed using this kit. According to our results, this molecular kit has shown high specificity and sensitivity in detecting dermatophytes, regardless of sample quality. On the other hand, and as expected, optimal samples allowed the identification of a higher number of dermatophytes by conventional mycological diagnosis, compared to non-optimal samples. Finally, we have suggested several strategies for the practical use of such a kit in a medical laboratory for quick pathogen detection.

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Section: Discussionmentioning

confidence: 63%

Optimising the diagnostic strategy for onychomycosis from sample collection to FUNGAL identification evaluation of a diagnostic kit for real‐time PCR

Petinataud

Berger

Ferdynus

et al. 2016

Mycoses

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“…In another study, employment of PCR increased detection of T. rubrum in nail scrapings by approximately 20 %, whereas positive T. rubrum culture but negative PCR was found in 3 % of samples (Brasch et al, 2011). In addition, the specific commercial PCR, used in the present study, was evaluated in four other studies also (Brillowska-Dabrowska et al, 2007, 2010Chandran et al, 2013;Kondori et al, 2010). These studies outline the importance of the dermatophyte PCR kit use as it increases detection rates by 10 to 19.5 %, as compared to cultures alone.…”

Section: Discussionmentioning

confidence: 74%

“…Conventional PCRs benefit from simplicity and lower cost, and target the identification of the most common dermatophyte, T. rubrum (Brasch et al, 2011), or pan-dermatophytes (Dhib et al, 2012;Luk et al, 2012). By means of a multiplex PCR, simultaneous identification of T. rubrum and pan-dermatophytes (Brillowska-Dabrowska et al 2007, 2010Kondori et al, 2010;Chandran et al, 2013; the present study) or T. rubrum, T. mentagrophytes and pan-dermatophytes (Dhib et al, 2014) is achieved. Moreover, Kim et al (2011) identified nine different dermatophyte species, and Mehlig et al (2014) identified an assortment of dermatophytes along with non-dermatophyte moulds (Scopulariopsis brevicaulis, Aspergillus spp.)…”

Section: Discussionmentioning

confidence: 85%

Evaluation of a commercial PCR test for the diagnosis of dermatophyte nail infections

Spiliopoulou

Bartzavali

Jelastopulu

et al. 2015

Journal of Medical Microbiology

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Tinea unguium, known as onychomycosis, is a dermatophyte infection of nails with worldwide distribution. Conventional methods for detecting fungi in nail specimens are either non-specific (microscopy) or insensitive (culture). PCR has been used to improve sensitivity in detecting the causative fungi in nail specimens from patients with suspected onychomycosis. Results of a commercial multiplex PCR for the detection of dermatophytes, especially Trichophyton rubrum (the main dermatophyte implicated), as compared to conventional methods are presented. A total of 418 nail scrapings obtained from dermatological outpatients were handled in the Laboratory of Microbiology between May 2010 and May 2013. Among them, multiplex PCR detected 126 (30.1 %) dermatophyte-positive samples, whereas culture revealed 44 (10.5 %). Direct microscopy revealed 63 (15.1 %) positive specimens. T. rubrum was identified in 116 out of 126 (92 %) positive PCR samples and 40 out of 44 (91 %) dermatophyte-positive cultures. Implementation of PCR increased species-specific detection of dermatophytes by 21.1 %, leading to a threefold increase as compared to culture alone. Multiplex PCR offers a time-saving diagnostic tool for tinea unguium and augments laboratory assistance to clinical evaluation for proper treatment. INTRODUCTIONTinea refers to superficial infection of skin, hair and nails due to one of three fungal genera, Microsporum, Epidermophyton and Trichophyton, collectively known as dermatophytes (Clayton & Midgley, 1989;Hay, 1995;Moriarty et al., 2012). These associated infections are among the most common diseases worldwide and cause serious chronic morbidity. Tinea unguium, a dermatophyte infection of nails, also known as onychomycosis, has a prevalence of at least 12.4 % in the general population of Europe (Moriarty et al., 2012), whereas in older individuals it is as high as 50 % (Salgo et al., 2003). The disease is often atypical and aggressive in patients with untreated human immunodeficiency virus infection. Patients with psoriasis not only have an increased risk of onychomycosis but also require laboratory confirmation as the two conditions may be clinically similar (Moriarty et al., 2012). Trichophyton rubrum is the main pathogen implicated (Brillowska-Dabrowska et al., 2007;Tsoumani et al., 2011), followed by Trichophyton interdigitale, formerly Trichophyton mentagrophytes var. interdigitale (Cafarchia et al., 2013;Clayton & Midgley, 1989; Gräser et al., 1999;Nenoff et al., 2007). Less commonly associated species are Epidermophyton floccosum and Trichophyton verrucosum (Moriarty et al., 2012). In addition to dermatophytes, Candida and non-dermatophyte moulds may be recovered from clinically affected nails; however, their clinical significance is controversial (Brillowska-Dabrowska et al., 2007). Conventional diagnosis is based on detection of fungal elements by direct microscopy of clinical specimens, followed by culture and morphological identification of the fungus. The whole procedure is time-consuming, requiring 10 to 15 ...

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“…Tenyésztés mellett a mikroszkópos vizsgálat is része a laboratóriumi vizsgálatnak, mert a számos esetben negatív tenyésztési eredmény mellett a mikroszkópos vizsgálat pozitivitása vezet diagnózishoz. (8) A hagyományos diagnosztikai módszerek mellett rendkívül hasznos vizsgálat a PCR technika is, amely magas szenzitivitásával segíti a diagnó-zist, valamint magas negatív prediktív értéke is van (9).…”

Section: Megbeszélésunclassified

Onychomycosis - a kórokozók fajspektruma és terápia

Mihalik¹,

Nemes-Nikodém²,

Máthé³

et al. 2013

BVSZ

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ÖSSZEFOGLALÁS Az onychomycosis a népesség 5-20%-át érintô civilizá-ciós betegség. A körmöt érintô elváltozások több mint 50%-áért gomba okozta fertôzések felelôsek. A szerzôk 2006. 07. 01.-2012. 12. 31 Key words: onychomycosis -Trichophyton rubrumyeast, mouldAz onychomycosis (Tinea unguium) gyakoriságának kö-szönhetôen a bôrgyógyászat egyik kiemelt fontosságú területe. Egyes felmérések szerint a körömeltérések több mint feléért gombafertôzések felelôsek (1). Az onychomycosis nem csupán kozmetikai probléma, diszkomfort érzés mellett súlyos esetben bakteriális felülfertôzôdés (erysipelas, cellulitis, phlegmone) rizikóját is fokozza (2). Onychomycosis kialakulására hajlamosít az idôsebb élet-kor, gyakori nedves környezet (úszás, házimunka), elégte-len lábhigiéne, mikózis pedis és interdigitális mikózis, psoriasis, diabetes mellitus, immunfunkció romlással járó állapotok és genetikai tényezôk szerepét is igazolták a hátterében. Egyes szerzôk szerint a mikózis pedis kezelé-sével az onychomycosis kialakulása megelôzhetô, míg mások a mikózis pedis és onychomycosis külön etiológiá-jára hívják fel a figyelmet (3-5). Klinikai kép alapján megkülönböztetünk distalis-lateralis subungualis onycomycosist (DLSO), proximalis subungualis onychomycosist (PSO), fehér superficialis onychomycosist (FSO) és totális dystróphiás onychomycosist (TDO). Egyszerre több lábköröm vagy kézköröm is érintett lehet. Jellemzô a körömlemez sárgás-barna elszínezôdése, megvastagodása, letöredezése, a köröm alatt morzsalékony massza jelenlé-te. A lábkörmökön dermatophytonok, a kézkörmökön sarjadzó gombák fordulnak elô gyakrabban. A DLSO és PSO formákban a Trichophyton rubrum, a FSO formában a T. mentagrophytes fajok a legvalószínûbb kórokozók (6, 7). A diagnózist a klinikai kép mellett a kórokozó gomba azonosítása (mikroszkópos vizsgálat, tenyésztés) jelenti.A szerzôk retrospektív módon elemzik és foglalják össze a Semmelweis Egyetem Bôr-, Nemikórtani és Bôr-onkológiai Klinikán onychomycosis miatt vizsgált és kezelt betegek körömkaparék mintáiból igazolt gombafertô-zések kórokozóinak eloszlási gyakoriságát 2006. július 1. és 2012. december 31. közötti idôperiódusban. MódszerekMintavétel: Anamnézis felvétel, fizikális vizsgálat és a kezeletlen beteg köröm alkoholos tisztítása után körömkaparék illetve törmelék nyerése történt steril tárgylemezre. 95

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Complementary role of a polymerase chain reaction test in the diagnosis of onychomycosis

Abstract: This study demonstrates that PCR increases the sensitivity of detection of dermatophytes in nail specimens. Despite its limitations, the use of PCR can complement direct microscopic examination and fungal cultures to aid clinicians in the diagnosis of suspected dermatophytic onychomycosis.

Cited by 19 publications

References 16 publications

Optimising the diagnostic strategy for onychomycosis from sample collection to FUNGAL identification evaluation of a diagnostic kit for real‐time PCR

Optimising the diagnostic strategy for onychomycosis from sample collection to FUNGAL identification evaluation of a diagnostic kit for real‐time PCR

Evaluation of a commercial PCR test for the diagnosis of dermatophyte nail infections

Onychomycosis - a kórokozók fajspektruma és terápia

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