|Year : 2015 | Volume
| Issue : 2 | Page : 314-316
A rare case of onychomycosis caused by Emericella quadrilineata (Aspergillus tetrazonus)
D Sharma1, MR Capoor1, V Ramesh2, S Gupta3, MR Shivaprakash3, A Chakrabarti3
1 Department of Microbiology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India
2 Department of Dermatology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India
3 Center of Advance Research in Medical Mycology, WHO Collaborating Center for Reference and Research of Fungi of Medical Importance, National Culture Collection of Pathogenic Fungi, Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
|Date of Submission||16-Jan-2014|
|Date of Acceptance||13-Oct-2014|
|Date of Web Publication||10-Apr-2015|
M R Capoor
Department of Microbiology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi
Source of Support: None, Conflict of Interest: None
Onychomycosis is a common chronic nail disorder where dermatophytes are the predominant pathogens. However, non-dermatophytic moulds like Aspergillus can also be implicated as the causative agents. Herein, we report a rare case of onychomycosis due to Emericella quadrilineata ( Aspergillus tetrazonus) in an apparently immunocompetent host.
Keywords: Emericella quadrilineata (Aspergillus tetrazonus), non-dermatophytic mould, Onychomycosis
|How to cite this article:|
Sharma D, Capoor M R, Ramesh V, Gupta S, Shivaprakash M R, Chakrabarti A. A rare case of onychomycosis caused by Emericella quadrilineata (Aspergillus tetrazonus). Indian J Med Microbiol 2015;33:314-6
|How to cite this URL:|
Sharma D, Capoor M R, Ramesh V, Gupta S, Shivaprakash M R, Chakrabarti A. A rare case of onychomycosis caused by Emericella quadrilineata (Aspergillus tetrazonus). Indian J Med Microbiol [serial online] 2015 [cited 2020 Jan 25];33:314-6. Available from: http://www.ijmm.org/text.asp?2015/33/2/314/153561
| ~ Introduction|| |
Onychomycosis comprises a major chunk (>50%) of all nail abnormalities.  Though mainly caused by dermatophytes, non-dermatophytic mould cases are also on the rise, comprising 2-22% of all cases of onychomycosis. , The non-dermatophytic moulds most frequently isolated from diseased nails are Aspergillus spp., Fusarium spp., Scopulariopsis brevicaulis, Scytalidium dimidiatum, S. hyalinum, Onychocola canadensis.,, Geographical differences exist in the epidemiology of onychomycosis. Though non-dermatophytic moulds are environmental saprophytes, their increasing incidence in nail disorders can be attributed to some underlying condition like diabetes, peripheral vascular disease, trauma, etc., although no such factor can be elicited in half of the cases. We report here a rare case of onychomycosis due to Emericella quadrilineata (Aspergillus tetrazonus) in an apparently immunocompetent patient.
| ~ Case Report|| |
The patient, a 45-year-old male from New Delhi, presented with dystrophy of four nails of both the left and right hands each, as well as first three toenails of both feet. Transverse striations were present on all the nail plates and white patches were present proximally [Figure 1]. The patient was employed as an operation theatre technician and was non-diabetic. He could neither recall any trauma associated with the nails nor was there history of any long-term steroid use or any other drug use. For mycological examination, scrapings were collected from the basal layer of the nail plate as well as areas of hyperkeratosis from both the fingernails and toenails. The specimen was subjected to direct microscopic examination in 40% KOH mounts. Fungal elements were seen in the form of thick hyaline septate hyphae with dichotomous branching. The nail specimen was then cultured in two sets of media using Walshe and English inoculum counting technique.  Tubes containing Sabouraud dextrose agar (SDA) with 0.05% chloramphenicol and SDA with 0.05% chloramphenicol and 0.5% cycloheximide were incubated at 25°C and 37°C for 4 weeks. The SDA tube with 0.05% chloramophenicol showed mold-like growth, which was further identified as E. quadrilineata (A. tetrazonus) on the basis of detailed macroscopic and microscopic study. The SDA tube with both chloramphenicol and cycloheximide did not yield any dermatophyte or any other mould growth. Macroscopic colony morphology of the growth revealed floccose grey colonies with a purplish centre [Figure 2]. Microscopic features of lactophenol cotton blue mount of the growth showed light brown smooth-walled conidiophores with hemispherical vesicles bearing biseriate conidiogenous cells. Metulae and phialides covered only the upper half of the vesicle. Conidia were spherical and finely roughened. After about two weeks of incubation, ascomata surrounded by hülle cells were formed [Figure 3]. The asci were 8-spored and spherical. The ascospores were smooth-walled, lenticular, with four short equatorial crests, two of which were seen with difficulty under oil immersion lens (1000×) [Figure 4]. Repeat examination of the nail sample after a week revealed hyaline septate hyphae with dichotomous branching on direct microscopy and duplicate set of SDA yielded growth of E. quadrilineata (A. tetrazonus). No other fungi were isolated. For reconfirmation of the isolate, it was sent to the Post Graduate Institute of Medical Education and Research, Chandigarh, India for molecular confirmation by DNA sequencing. It was confirmed as E. quadrilineata (A. tetrazonus) by sequencing of ITS 1 and ITS 4 region of rDNA (NCCPF number 840011). The patient was diagnosed as superficial white onychomycosis due to E. quadrilineata (A. tetrazonus) and was put on local and systemic therapy. Oral terbinafine 250 mg daily was started along with terbinafine cream and powder. Follow up of the patient after three months showed 100% reduction in white patches and transverse striations on nails of the hands and toes.
|Figure 1: Infection of the toenails due to A. tetrazonus showing transverse striations and white patches|
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|Figure 2: Macroscopic colony morphology in Sabouraud dextrose agar showing floccose grey colonies with a purplish centre|
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|Figure 3: Lactophenol cotton blue mount showing hülle cells (Magnification, × 1000)|
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|Figure 4: Lactophenol cotton blue mount showing ascospores of E. quadrilineata (A. tetrazonus) with equatorial crests (Magnification, × 1000)|
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| ~ Discussion|| |
Although the most common causative agents of onychomycosis are dermatophytes and yeast-like fungi, the incidence of non-dermatophytic moulds have been increasing of late. The most frequently isolated Aspergillus spp. causing nail infections are A. niger, A. flavus, A. terreus, A. nidulans, A. fumigatus and A.versicolor. , Aspergillus spp. cause distal subungual and white superficial mycosis with partial or total dystrophy of the affected nail.  Repeat positive direct microscopy and culture and absence of a dermatophyte are the prerequisite conditions to associate a non-dermatophytic mould as the causative agent of a nail or skin infection.  These criteria were fulfilled in our report. The A. tetrazonus is an environmental saprophyte and has been previously isolated from sheep with mycotic dermatitis.  and was the causative agent of a human case of fungal sinusitis.  and invasive aspergillosis.  After careful review of pertinent reports in literature, up till now, there is only a single case report of E. quadrilineata (A. tetrazonus) causing onychomycosis.  This is probably the second case. Recent reports in literature highlight its pathogenic role in invasive aspergillosis.
In conclusion, this case report is the second clinical description of the pathogenic role of E. quadrilineata (A. tetrazonus) in humans which apparently depicts the emerging role of this fungus in various human infections.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]