DM Kim, et al Ann Dermatol Vol. 25, No. 2, 2013 http://dx.doi.org/10.5021/ad.2013.25.2.232 CASE REPORT Onychomycosis Caused by Chaetomium globosum Dong Min Kim, Myung Hoon Lee, Moo Kyu Suh, Gyoung Yim Ha1, Heesoo Kim2, Jong Soo Choi3 Departments of Dermatology, 1Laboratory Medicine, 2Microbiology, College of Medicine, Dongguk University, Gyeongju, 3Department of Dermatology, College of Medicine, Yeungnam University, Daegu, Korea Onychomycosis is usually caused by dermatophytes, but -Keywords- some nondermatophytic molds and yeasts are also asso- Chaetomium, Onychomycosis ciated with invasion of nails. The genus Chaetomium is a dematiaceous nondermatophytic mold found in soil and plant debris as a saprophytic fungus. We report the first INTRODUCTION Korean case of onychomycosis caused by Chaetomium globosum in a 35-year-old male. The patient showed brown- Onychomycosis is caused mainly by dermatophytes but ish-yellow discoloration and subungual hyperkeratosis on occasionally by nondermatophytic fungi including Scopu- the right toenails (1st and 5th) and left toenails (1st and 4th). lariopsis brevicaulis, Aspergillus species (spp.), Fusarium Direct microscopic examination of scraping on the pota- spp., Acremonium spp., and Chaetomium spp. which ssium hydroxide preparation revealed septate hyphae and have often been considered as saprophytic or oppor- repeated cultures on Sabouraud’s dextrose agar (SDA) with- tunistic fungi1. So far such molds have been regarded as out cycloheximide slants showed the same fast-growing saprophytic or opportunistic fungi and thus have been colonies, which were initially velvety white then turned to ignored. Recently, as a consequence of the increase in the dark gray to brown. However, there was no growth of colony number of cases of immune suppression and environ- on SDA with cycloheximide slants. Brown-colored septated mental changes, more attention has been given to this hyphae, perithecia and ascospores were shown in the slide wide, but generally not pathogenic group of fungi2. This culture. The DNA sequence of internal transcribed spacer apparent emergence might be an artifact of improved region of the clinical sample was a 100% match to that of C. diagnostic techniques and increased awareness that these globosum strain ATCC 6205 (GenBank accession number fungi are potential etiologic agents3. EF524036.1). We confirmed C. globosum by KOH mount, The genus Chaetomium, which belongs to ascomycetes, is colony, and light microscopic morphology and DNA a dematiaceous mold found worldwide in soil and plant sequence analysis. The patient was treated with 250 mg oral debris as a saprophyte. Chaetomium species are rarely terbinafine daily and topical amorolfine 5% nail lacquer for involved in human infection, but have been reported to 3 months. (Ann Dermatol 25(2) 232∼236, 2013) cause subcutaneous phaeohyphomycosis and systemic infections in immunocompromised patients as well as onychomycosis in healthy subjects4. There have been only four cases of onychomycosis caused by Chaetomium Received July 22, 2011, Revised September 9, 2011, Accepted for globosum, which is the most frequently isolated species 4-10 publication October 1, 2011 among Chaetomium spp. Corresponding author: Moo Kyu Suh, Department of Dermatology, Here, we report the first case in Korea of onychomycosis Dongguk University Gyeongju Hospital, College of Medicine, Dong- caused by C. globosum. The identification of the causative guk University, 87 Dongdae-ro, Gyeongju 780-350, Korea. Tel: 82- fungus was confirmed by clinical findings, repeated fungal 54-770-8268, Fax: 82-54-773-1581, E-mail: [email protected] isolation, light microscopy and sequencing analysis of the This is an Open Access article distributed under the terms of the internal transcribed spacer (ITS) region in ribosomal RNA Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/3.0) which permits unrestricted genes. non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 232 Ann Dermatol Onychomycosis Caused by Chaetomium globosum CASE REPORT ved in 20% KOH preparation from the toenail lesions. Nail specimens were cultured on two Sabouraud’s A 35-year-old male presented with a 2-year history of dextrose agar (SDA) without cycloheximide slants at 25oC brownish-yellow discoloration and subungual hyperkera- for a week to yield several identical colonies. However, tosis on the right toenails (1st and 5th) and left toenails there was no growth of colony on SDA with cyclohexi- (1st and 4th) (Fig. 1, 2). The patient was otherwise in good mide slants. These rapid growing colonies were initially health and he denied nail trauma or dystrophic nail velvety white then turned to dark gray to brown (Fig. 3). abnormalities prior to the onset of the present lesions. The reverse surface of the colonies revealed an orange-tan There was no history of other diseases except for toenail color. Subcultures on agar plates exhibited the same dystrophy. On the visit, laboratory studies including a results (Fig. 4, 5). When the slide cultures of fungal colo- complete blood cell count with differentials, liver and nies were stained with lactophenol cotton blue, the renal function test, venereal disease research laboratory, urinalysis, stool examination, hepatitis viral test, human immunodeficiency virus test, chest X-ray, and electro- cardiogram were all within normal limits or negative. In mycological examination, septated hyphae were obser- Fig. 3. Multiple, dark grey to brown colonies with aerial mycelium on Sabouraud’s dextrose agar slants after incubation Fig. 1. Brownish-yellow discoloration with hyperkeratosis on the at 25oC for 1 week. right toenails. Fig. 4. A rapid growing, dark grey to brown colony with aerial mycelium on Sabouraud’s dextrose agar plate after incubation Fig. 2. Close up view of the right first toenail. at 25oC for 1 week. Vol. 25, No. 2, 2013 233 DM Kim, et al Fig. 7. Close-up view of perithecium which demonstrates ostioles and contains asci and single-celled ascospores (Lactophenol Fig. 5. Reverse surface of Sabouraud’s dextrose agar plate after cotton blue stain, ×200). incubation at 25oC for 1 week. Fig. 8. Brown-colored septated hyphae and lemon-shaped asco- spores (Lactophenol cotton blue stain, ×400). Fig. 6. Large, dark brown to black, flask shaped perithecia with hair-like filamentous appendages (Lactophenol cotton blue stain, ×400). Fig. 9. Alignment of internal transcribed spacer (ITS) sequences of the sample from the patient and Chaetomium globosum strain ATCC 6205 (GenBank accession number EF524036.1). The sequences of ITS for the clinical sample was a 100% match to that of C. globosum strain ATCC 6205 (GenBank accession number EF524036.1). morphological characteristics such as brown-colored sep- tained asci and single-celled ascospores which were olive tated hyphae, perithecia and ascospores were observed by brown and lemon-shaped (Fig. 7, 8). light microscopy (Fig. 6). Perithecia were large and dark The ITS region of ribosomal RNA genes was amplified brown to black color, revealing a globose to flask shape using DNA of the fungal colonies cultured from nail with unbranched, hair-like filamentous appendages on specimens. For molecular biologic analysis, DNA was their surface. Perithecia demonstrated ostioles and con- extracted from the cultured colonies and the base seq- 234 Ann Dermatol Onychomycosis Caused by Chaetomium globosum uence of ITS was identified. Subsequently, it was com- cosis4,7-10. This is the first report of Chaetomium infection pared to the base sequence of C. globosum strain ATCC of the nail in a patient in Korea. 6205 (GenBank accession number: EF524036.1), which As nondermatophytic molds including C. globosum are was stored in GenBank, using the Blast program. The saprophytes, it is not feasible to distinguish the causative result was 100% matched (Fig. 9). agents from contaminants when these molds are isolated Based on the KOH mount, mycological finding, light from the nail specimens14. Therefore, it should be checked microscopy and sequence analysis of the ITS region, the if the characteristic hyphae or spores are present in KOH isolate was finally identified as C. globosum. The patient preparation, if identical colonies are obtained from speci- was treated with 250 mg oral terbinafine daily and topical mens, and if the same causative mold is identified from amorolfine 5% nail lacquer for 3 months. repeated cultures15. In this case, fungal elements were found by microscopy, and the same fungal species were DISCUSSION isolated from the repetitive cultures of toenail specimens. The identification of C. globosum had been based on the Onychomycoses comprising 50% of all onychopathies morphological features of the colonies. Lately, however, are caused mainly by dermatophytes and less frequently sequencing analysis of the ITS region of ribosomal DNA by nondermatophytic molds and yeasts1. Onychomycosis has been considered necessary for definite identification caused by nondermatophytic molds comprises 1.45 to among the genus Chaetomium16,17. Morphological featur- 17.6% of the total cases, and Aspergillus spp., Scopulari- es of C. globosum include fast-growing dark gray colonies, opsis spp., Fusarium spp., Acremonium spp., and Chaeto- peritheca with hairy filamentous appendages, and ostioles mium spp. may be the causes2,11-13. at the bottom of peritheca containing asci and ascospores. Since the first definition of the genus Chaetomium was Ascospores