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-
1
Campbell AW, Anyanwu EC, Morad M: Evaluation of the drug treatment and persistence of onychomycosis. .ScientificWorld J 4::760. ,2004. .
-
2
Gupta AK, Jain HC, Lynde CW, et al: Prevalence and epidemiology of onychomycosis in patients visiting physicians’ offices: a multicenter Canadian survey of 15,000 patients. .J Am Acad Dermatol 43::244. ,2000. .
-
3
Roberts DT: Prevalence of dermatophyte onychomycosis in the United Kingdom: results of an omnibus survey. .Br J Dermatol 126: (suppl 39):23. ,1992. .
-
4
Summerbell RC, Kane J, Krajden S: Onychomycosis, tinea pedis and tinea manuum caused by non-dermatophytic filamentous fungi. .Mycoses 32::609. ,1989. .
-
5
Gupta AK, Konnikov N, MacDonald P, et al: Prevalence and epidemiology of toenail onychomycosis in diabetic subjects: a multicentre survey. .Br J Dermatol 139::665. ,1998. .
-
6
Gupta AK, Scher RK, De Doncker P: Current management of onychomycosis: an overview. .Dermatol Clin 15::121. ,1997. .
-
7
Evans EG: Causative pathogens in onychomycosis and the possibility of treatment resistance: a review. .J Am Acad Dermatol 38::S32. ,1998. .
-
8
Graser Y, Kuijpers AF, Presber W, et al: Molecular taxonomy of Trichophyton mentagrophytes and T. tonsurans. .Med Mycol 37::315. ,1999. .
-
9
Gupta AK, Ryder JE, Skinner AR: Treatment of onychomycosis: pros and cons of antifungal agents. .J Cutan Med Surg 8::25. ,2004. .
-
10
Scher RK, Baran R: Onychomycosis in clinical practice: factors contributing to recurrence. .Br J Dermatol 149: (suppl 65):5. ,2003. .
-
11
Lecha M, Effendy I, Feuilhade de Chauvin M, et al: Treatment options: development of consensus guidelines. .J Eur Acad Dermatol Venereol 19: (suppl 1):25. ,2005. .
-
12
Olafsson JH, Sigurgeirsson B, Baran R: Combination therapy for onychomycosis. .Br J Dermatol 149: (suppl 65):15. ,2003. .
-
13
Evans EG, Sigurgeirsson B: Double blind, randomised study of continuous terbinafine compared with intermittent itraconazole in treatment of toenail onychomycosis. .BMJ 318::1031. ,1999. .
-
14
Gupta AK, De Doncker P, Scher RK, et al: Itraconazole for the treatment of onychomycosis. .Int J Dermatol 37::303. ,1998. .
-
15
Epstein E: How often does oral treatment of toenail onychomycosis produce a disease-free nail? an analysis of published data. .Arch Dermatol 134::1551. ,1998. .
-
16
Monod M, Baudraz-Rosselet F, Ramelet AA, et al: Direct mycological examination in dermatology: a comparison of different methods. .Dermatologica 179::183. ,1989. .
-
17
Zabawski EJ Jr, Styles AR, Cockerell CJ: Routine periodic acid-Schiff staining of nail plate fragments in fungal cultures for onychomycosis: a method to increase the sensitivity of diagnosis. .Cutis 66::456. ,2000. .
-
18
Weinberg JM, Koestenblatt EK, Jennings MB: Utility of histopathologic analysis in the evaluation of onychomycosis. .JAPMA 95::258. ,2005. .
-
19
Anane S, Aoun K, Zallagua N, et al: Onychomycosis in Tunis area: epidemiological and mycological data [in French]. .Ann Dermatol Venereol 128::733. ,2001. .
-
20
Baudraz-Rosselet F, Frenk E: In vitro nail invasion by pathogenic and non-pathogenic fungi under different culture conditions. .Mycoses 33::553. ,1990. .
-
21
Lateur N, Mortaki A, Andre J: Two hundred ninety-six cases of onychomycosis in children and teenagers: a 10-year laboratory survey. .Pediatr Dermatol 20::385. ,2003. .
-
22
Summerbell RC, Cooper E, Bunn U, et al: Onychomycosis: a critical study of techniques and criteria for confirming the etiologic significance of nondermatophytes. .Med Mycol 43::39. ,2005. .
-
23
Gupta AK, Ryder JE, Baran R, et al: Non-dermatophyte onychomycosis. .Dermatol Clin 21::257. ,2003. .
-
24
Gupta AK, Zaman M, Singh J: Fast and sensitive detection of Trichopyton rubrum DNA from the nail samples of patients with onychomycosis by a double-round polymerase chain reaction-based assay. .Br J Dermtol 157::698. ,2007. .
-
25
Anderson TD, Ross JP, Roby RK, et al: A validation study for the extraction and analysis of DNA from human nail material and its application to forensic casework. .J Forensic Sci 44::1053. ,1999. .
-
26
Avner S, Nir N, Henri T: Combination of oral terbinafine and topical ciclopirox compared to oral terbinafine for the treatment of onychomycosis. .J Dermatol Treat 16::327. ,2005. .
-
27
Gupta AK: Ciclopirox topical solution, 8% combined with oral terbinafine to treat onychomycosis: a randomized, evaluator-blinded study. .J Drugs Dermatol 4::481. ,2005. .
-
28
Gupta AK, Lynch LE: Management of onychomycosis: examining the role of monotherapy and dual, triple, or quadruple therapies. .Cutis 74::5. ,2004. .
-
29
Clayton YM: Clinical and mycological diagnostic aspects of onychomycoses and dermatomycoses. .Clin Exp Dermatol 17: (suppl 1):37. ,1992. .
-
30
Fletcher CL, Hay RJ, Smeeton NC: Onychomycosis: the development of a clinical diagnostic aid for toenail disease: part I. Establishing discriminating historical and clinical features. .Br J Dermatol 150::701. ,2004. .
-
31
Midgley G, Moore MK, Cook JC, et al: Mycology of nail disorders. .J Am Acad Dermatol 31::S68. ,1994. .
-
32
Weinberg JM, Koestenblatt EK, Tutrone WD, et al: Comparison of diagnostic methods in the evaluation of onychomycosis. .J Am Acad Dermatol 49::193. ,2003. .
-
33
Arca E, Saracli MA, Akar A, et al: Polymerase chain reaction in the diagnosis of onychomycosis. .Eur J Dermatol 14::52. ,2004. .
-
34
Kardjeva V, Summerbell R, Kantardjiev T, et al: Forty- eight-hour diagnosis of onychomycosis with subtyping of Trichophyton rubrum strains. .J Clin Microbiol 44::1419. ,2006. .
-
35
Okeke CN, Tsuboi R, Kawai M, et al: Isolation of an intron-containing partial sequence of the gene encoding dermatophyte actin (ACT) and detection of a fragment of the transcript by reverse transcription-nested PCR as a means of assessing the viability of dermatophytes in skin scales. .J Clin Microbiol 39::101. ,2001. .
Diagnosis of Trichophyton rubrum from Onychomycotic Nail Samples Using Polymerase Chain Reaction and Calcofluor White Microscopy
Mycology Section, Mediprobe Research Inc, London, Ontario, Canada.
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Background: A high rate of false-negative dermatophyte detection is observed when the most common laboratory methods are used. These methods include microscopic observation of potassium hydroxide–digested nail clippings and culture methods using agar-based media supplemented with cycloheximide, chloramphenicol, and gentamicin to isolate dermatophytes. Microscopic detection methods that use calcofluor white staining or periodic acid–Schiff staining may also be substituted for and have previously been reported to be more sensitive than potassium hydroxide–digested nail clippings.
Methods: Trichophyton rubrum infections were detected directly from nails in a double-round polymerase chain reaction assay that uses actin gene–based primers. This method was compared with detection of fungal hyphae by using calcofluor white fluorescence microscopy of nail samples collected from 83 patients with onychomycosis who were undergoing antifungal drug therapy.
Results: Twenty-six of 83 samples (31.3%) were found to be positive by calcofluor white fluorescence microscopy, and 21 of 83 samples (25.3%) yielded positive results for T rubrum when actin gene–based primers in a double-round polymerase chain reaction assay were used. When calcofluor white fluorescence microscopy and polymerase chain reaction assay were used, the combined detection was 46.9% compared with 31.3% when calcofluor microscopy and culture of nail samples on Sabouraud’s dextrose agar supplemented with cycloheximide, chloramphenicol, and gentamicin were used.
Conclusions: These results suggest that the use of a direct DNA protocol is an alternative method for detecting Trichophyton infections. When this protocol is used, the presence of T rubrum DNA is directly detected. However, the viability of the dermatophyte is not addressed, and further methods need to be developed for the detection of viable T rubrum directly from nail samples. (J Am Podiatr Med Assoc 98(3): 224–228, 2008)
