Detection of common dermatophytes in clinical specimens using a simple quantitative real-time TaqMan polymerase chain reaction assay

Ohst, Torsten; Kupsch, Christiane; Gräser, Yvonne

doi:10.1111/bjd.14198

Cited by 50 publications

(65 citation statements)

References 26 publications

(28 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Our data are in line with previous reports on RT‐PCR assays for the detection of dermatophytes; in general, an increase in the positivity rate of between 4% and 22% when compared with culture has been noted (in our case, it was 22·2%) . When PCR is compared with microscopy, reported data are inconsistent: in some studies microscopy was the method with the highest positivity rate, i.e.…”

Section: Discussionsupporting

confidence: 89%

Development and evaluation of a pan‐dermatophyte polymerase chain reaction with species‐level identification using sloppy molecular beacon probes

Walser

Bosshard

2019

Br J Dermatol

View full text Add to dashboard Cite

Summary Background Conventional laboratory diagnosis of dermatophyte infection is cumbersome and time‐consuming. Objectives We aimed to establish a simple, robust and rapid molecular diagnostic assay for the detection of dermatophytes and optionally nondermatophytes in clinical specimens. Materials and methods We developed a two‐tube pan‐dermatophyte polymerase chain reaction (PCR) assay using six sloppy molecular beacon (SMB) probes. The first PCR uses dermatophyte‐specific primers and enables detection and identification of most dermatophyte species. The second PCR with pan‐fungal primers allows further differentiation of Trichophyton interdigitale and T. mentagrophytes/T. quinckeanum, T. violaceum and T. soudanense, and T. tonsurans and T. equinum, and detection of nondermatophytes. The test was evaluated with 306 clinical specimens by comparing it with the results of microscopy and culture. Results In melting‐curve analyses, species‐specific melting temperature signatures of the SMBs were defined, and thus, our new PCR enabled detection and species‐level identification of at least 19 dermatophyte species. Sensitivity and specificity of PCR for detection of dermatophytes in clinical samples were estimated to be 96·9% and 90·4%, for culture 46·7% and 98·7%, and for microscopy 91·4% and 84·0%, respectively. The detection of nondermatophytes by PCR and culture did not correlate. Conclusions The new assay showed excellent performance characteristics for the detection of dermatophytes and is significantly faster than culturing techniques, which makes it very promising for routine diagnostics of dermatophytosis. We noted that the detection of nondermatophytes in our assay currently has no benefit.

show abstract

Section: Discussionsupporting

confidence: 89%

Development and evaluation of a pan‐dermatophyte polymerase chain reaction with species‐level identification using sloppy molecular beacon probes

Walser

Bosshard

2019

Br J Dermatol

View full text Add to dashboard Cite

show abstract

“…In such cases, the medical history is not able to reveal the source of asymptomatic infections (Gnat, Łagowski, Nowakiewicz, & Zięba, ; Gnat, Łagowski, Nowakiewicz, & Zięba, ). On the other hand, the identification of the species of animal from which the infection may have spread is not sufficient due to the changing reservoirs of zoophilic dermatophytes (Brasch & Zaldua, ; Gnat, Łagowski, Nowakiewicz, Trościańczyk, et al, ; Ohst, Kupsch, & Graser, ; Weitzman & Summerbell, ). It is commonly agreed by dermatologists and veterinarians that the zoophilic fungus T. verrucosum is the most frequent worldwide aetiologic agent of dermatophytosis in cattle (Gnat, Łagowski, Nowakiewicz, Trościańczyk, et al, ; Gnat, Łagowski, Nowakiewicz, & Zięba, ; Gnat, Łagowski, Nowakiewicz, & Zięba, ; Havlickova et al, ).…”

Section: Discussionmentioning

confidence: 99%

In search of the source of dermatophytosis: Epidemiological analysis of Trichophyton verrucosum infection in llamas and the breeder (case report)

Łagowski

Gnat

Nowakiewicz

et al. 2019

Zoonoses and Public Health

View full text Add to dashboard Cite

During the last few years, the number of cases of Trichophyton verrucosum isolation from humans suffering from mycoses has been constantly increasing, which is correlated with the presence of an increasing number of outdoor breeding farms. Farmers and their families as well as veterinarians and technicians involved in handling the animals are at a higher risk of infection. One of the most important aims of mycological diagnostics is epidemiological analysis. Typically, the history of the disease is not sufficient to indicate reliably and eliminate the outbreak of infection. PCR fingerprinting methods are a useful tool in this type of analysis, which is presented in this study. The main aim is to present diagnostic and epidemiological analyses of dermatophyte isolates from llamas and their breeder. In two llamas, round alopecia sites or ca. 2‐cm excoriations covered with thickened scaling epidermis were noticed at the border of the head and neck with a distinct tendency towards hair loss. Tinea unguium was noticed in a nail of the breeder's right hand. Direct analysis of the material from the clinical lesions revealed the presence of arthrospores. The macro‐ and micromorphology of the isolates were homogeneous and characteristic for T. verrucosum. The identification analysis based on the ITS sequences confirmed the previous morphological diagnostic examination. The MP‐PCR and MSP‐PCR analysis indicated high invariability of the genomes of the strains isolated from the human and animals. The epidemiological research has indicated an identical source of dermatophyte infection in the breeder and the lamas. To sum up, the number of pets and farm animals is increasing and dermatologists should always be informed about possible dermatophyte transmission sources. The possibility of transmission of zoophilic dermatophytes from humans to animals is a suggestion for further analysis; therefore, this type of transmission should be considered in dermatological studies.

show abstract

“…Interestingly, nearly half of the human patients have acquired the T. verrucosum infection indirectly, without exposure to cattle as a main fungal reservoir . A factor that connects humans suffering from T. verrucosum infections is life on a farm or their relatives working on a farm, especially in the case of farmers, animal breeders and veterinarians . This observation may suggest that acquisition of contamination through contact with spores present on soil is also possible .…”

Section: Discussionmentioning

confidence: 99%

Comparison of in vitro activities of 11 antifungal agents against Trichophyton verrucosum isolates associated with a variety hosts and geographical origin

Łagowski

Gnat

Nowakiewicz

et al. 2019

Mycoses

View full text Add to dashboard Cite

Summary The high prevalence of dermatophytosis in animals is usually associated with extra expenditure on prevention, diagnosis and long‐term treatment. Humans are usually infected from animals, also from asymptomatic carriers, through direct contact or indirectly via fungus‐bearing hair, scales and fomites. Despite the medical importance of Trichophyton verrucosum infections, there are limited in vitro data on the fungal susceptibility to antifungal drugs, including new‐generation triazoles, imidazoles and allyloamines. The aim of the current study was to evaluate comprehensively the in vitro activity of 11 antifungal drugs against a large collection of T. verrucosum isolates obtained in Poland, Latvia, Lithuania and Slovakia from humans and animals using a microdilution assay. In vitro susceptibility testing of 11 antifungal drugs was performed according to the Clinical and Laboratory Standards Institute (CLSI) document M38. The MICs of clotrimazole, ciclopirox, enilconazole, miconazole, naftifine and terbinafine against all T. verrucosum isolates were below 1 μg/mL, whereas those of fluconazole, griseofulvin, itraconazole, ketoconazole and voriconazole were above 1 μg/mL. Ciclopirox was demonstrated to have superior activity against all strains in comparison with the other drugs, whereas fluconazole exerted the weakest in vitro effect and exhibited the highest MIC values. Our study has shown that drugs of different chemical origin have satisfactory antifungal activity and can be promising candidates for the treatment of T. verrucosum dermatophytosis. Moreover, no significant disparity in drug sensitivity between isolates obtained from different hosts and geographical regions have been demonstrated.

show abstract

Detection of common dermatophytes in clinical specimens using a simple quantitative real-time TaqMan polymerase chain reaction assay

Abstract: The qRT-PCR assay developed in this study allows the specific and sensitive detection of relevant dermatophytes at low cost in a short time.

Cited by 50 publications

References 26 publications

Development and evaluation of a pan‐dermatophyte polymerase chain reaction with species‐level identification using sloppy molecular beacon probes

Development and evaluation of a pan‐dermatophyte polymerase chain reaction with species‐level identification using sloppy molecular beacon probes

In search of the source of dermatophytosis: Epidemiological analysis of Trichophyton verrucosum infection in llamas and the breeder (case report)

Comparison of in vitro activities of 11 antifungal agents against Trichophyton verrucosum isolates associated with a variety hosts and geographical origin

Contact Info

Product

Resources

About