|Year : 2015 | Volume
| Issue : 3 | Page : 435-437
Onychoprotothecosis: An uncommon presentation of protothecosis
NR Gandham1, CR Vyawahare1, N Chaudhaury1, RA Shinde2
1 Department of Microbiology, Padmashree Dr. Dnyandeo Yashwantrao Patil Medical College, Hospital and Research Centre, Pune - 411 018, Maharashtra, India
2 Department of Dermatology, Padmashree Dr. Dnyandeo Yashwantrao Patil Medical College, Hospital and Research Centre, Pune - 411 018, Maharashtra, India
|Date of Submission||19-Jul-2014|
|Date of Acceptance||03-Mar-2015|
|Date of Web Publication||12-Jun-2015|
N R Gandham
Department of Microbiology, Padmashree Dr. Dnyandeo Yashwantrao Patil Medical College, Hospital and Research Centre, Pune - 411 018, Maharashtra
Source of Support: None, Conflict of Interest: None
Onychomycosis is a fairly common condition seen in a dermatology clinic. Dermatophytes Trichophyton and Epidermophyton are the known filamentous fungi implicated. The yeast-like fungi such as Candida less commonly cause Onychomycosis. The genus Prototheca may on preliminary observation resemble yeast-like fungi but a detailed microscopy will reveal the absence of budding and presence of endospores. Onychoprotothecosis is an uncommon presentation of human protothecosis. Of the two Prototheca species (Prototheca zopfii and Prototheca wickerhamii) known to cause the disease, P. wickerhamii has been reported more commonly. We report a culture proven case of this condition caused by P. zopfii. The patient, a 55-year-old housewife presented with discolouration and breaking off of the right thumb and forefinger nails since a period of six months. Samples of nail scrapping sent to the Microbiology Laboratory were culture-positive for Prototheca. Speciation by the automated Vitek-2 system (bioMerieux) identified the isolate as P. zopfii, which was further confirmed at PGI, Chandigarh.
Keywords: Prototheca zopfii, protothecosis, onychoprotothecosis, ungual infection
|How to cite this article:|
Gandham N R, Vyawahare C R, Chaudhaury N, Shinde R A. Onychoprotothecosis: An uncommon presentation of protothecosis. Indian J Med Microbiol 2015;33:435-7
|How to cite this URL:|
Gandham N R, Vyawahare C R, Chaudhaury N, Shinde R A. Onychoprotothecosis: An uncommon presentation of protothecosis. Indian J Med Microbiol [serial online] 2015 [cited 2020 Jul 3];33:435-7. Available from: http://www.ijmm.org/text.asp?2015/33/3/435/158583
| ~ Introduction|| |
Prototheca species are algae, which do not produce chlorophyll. This fungal infection caused by Prototheca species or human protothecosis is rare. It mostly occurs following inoculation into subcutaneous tissues following trauma. Five species are identified in the genus Prototheca. Two of these species, namely Prototheca wickerhamii and Prototheca zopfii, have been identified as pathogens implicated in the human. The first human case reported for protothecosis was due to P. zopfii. However, subsequently most cases (about 100) of protothecosis have been due to P. wickerhamii. Clinically protothecosis can be of three types- i) Cutaneous ii) Olecranon bursitis iii) Disseminated or systemic infection. The first type may occur in immunocompetent individuals. Olecranon bursitis is considered separately as it is a common presentation. Disseminated or systemic infection is seen with some immune dysfunction. 
The rarer or more uncommon presentations include urinary tract infection, intestinal protothecosis, meningitis and ungual infection. Here, we report a culture proven case of ungual protothecosis/onychoprotothecosis, and discuss the cultural, identification and review of the reported literature of onychoprotothecosis.
| ~ Case- Noted|| |
A 55-year-old woman presented to the Outpatient Department (OPD) of Dermatology of Pad. Dr. D Y Patil Medical College, Hospital and Research Centre, Pune, a tertiary care hospital in Western Maharashtra, India, catering to a semi-urban population. She complained of noticing discolouration and detachment of the distal part of the right thumb and forefinger nails since the last six months. She also complained of a mild pain recently in the involved fingernails. A record of her history revealed no awareness of any preceding trauma. She was a housewife and carried out all household activities, including hand washing clothes, utensils as well as house cleaning and cooking. No one else in the family had any similar complaints.
On examination, a yellowish discolouration of the involved nails was seen. Onycholysis of the distal part of the right thumb and right forefinger was observed. The right middle fingernail also showed some yellowish discolouration [Figure 1]. The rest of the fingernails were uninvolved. The great toenails were blackish, while the other toenails were unremarkable. An examination of the oral mucosa, skin over hands and feet, intertriginous spaces, hair and scalp revealed no abnormality. A provisional diagnosis of onychomycosis was made based on the complaints, duration of the disease and examination. Nail clippings/scrapings from the affected nails were collected with aseptic precautions and sent to the Department of Microbiology for culture and microscopic examination. The patient was started on oral terbinafine 250 mg once a day and local application of Nail lacquer (ciclopirox olamine) once a day for one month.
The nail clippings received by the microbiology laboratory were processed by the routine laboratory protocol for fungal culture. A wet mount with 40% KOH (Potassium hydroxide) was made and observed under the microscope after four hours. It revealed no filamentous forms, but some globular yeast-like structures.
Cultures were set up on Sabouraud's dextrose agar (SDA) with and without chloramphenicol. One set was incubated at 37 degrees Celsius and the other at room temperature. In 72 hours, small white to cream yeast-like colonies appeared on all the slants, which on further incubation appeared larger. Gram stain revealed gram positive yeast-like cells of different sizes. The wet mount showed round to oval cells of varying sizes (about 5-15 microns) with varying number of endospores inside. Budding was absent. Lactophenol cotton blue (LPCB) preparation confirmed the above findings. Further, they appeared as asymmetric morula-like structures. They appeared as sporangia with two to five endospores inside [Figure 2] and [Figure 3] suggestive of genus Prototheca.  For confirmation, the culture was tested by Vitek-2 system using the YST card. The isolate was identified as P. zopfii with 99% probability (excellent identity). The isolate was sub-cultured on SDA and sent to National Culture Collection of Pathogenic Fungi (NCCPF), PGI Chandigarh for confirmation and was confirmed as P. zopfii.
|Figure 2: LPCB mount showing variable sizes of cells and endospores (×40)|
Click here to view
| ~ Discussion|| |
Among the yeast-like pathogens, genus Candida is the commonest. Organisms resembling yeast-like pathogens include genera Prototheca, Geotrichum, Aureobasidium and Sporothrix. Protothecosis in human beings is a rare infection. About 100 cases have been reported. It is worldwide in occurrence but the incidence is low. Infections are noted in cattle and canines. The genus Prototheca are achlorogenous algae differentiated from other algae such as Chlorella by their lack of chlorophyll. Of the five species currently known, two are implicated as pathogens- P. wickerhamii and P. zopfii. They are ubiquitous in waste water or sewage water from households. Patients with steroid use, solid organ malignancy or diabetes mellitus may be at risk of Protothecosis. The incubation period is thought to be in weeks. Cutaneous infection is the most frequently seen presentation. It may occur following documented traumatic inoculation. There may appear circumscribed or progressive indurated papular rash or nodular lesions.  Olecranon bursitis infections are preceded by injuries to elbow. Pre-existence of inflammatory conditions and treatment with injectables in the joint may provide conducive conditions for this infection. Systemic infections occur almost always in immune compromised conditions.  These include those on cancer treatment, and with solid organ tumors and immune deficiency diseases. The diagnosis can be made on histopathology and/or culture. 
Among the rarer presentations, there are few cases of ungual protothecosis. One case was published in 1997 by Galan and co-workers in Spain.  Another case was published in 2006 by Zaitz and co-workers.  Both the cases were in women with forefinger nail as the only affected fingernail. Further, they were culture proven cases, and in the first case histopathological evidence was also suggestive of the infection. The present case was a woman who had no history suggestive of immune suppression or alteration like diabetes mellitus, arthritis, long-term medication or malignancy. The previous two cases were due to P. wickerhamii and the present due to P. zopfii. Various treatment regimens have been attempted. These include topical and systemic antifungals and surgical procedures like excision.  This patient was started on antifungal therapy (systemic and topical) for a month based on the provisional clinical diagnosis and has not returned for a follow-up visit to date.
To the best of our knowledge, this is among the first reports of ungual protothecosis from Maharashtra, India. We report the case as it presented in an immunocompetent patient and was caused by P. zopfii. We would like to emphasise the need to diagnose this infection early and maintain a high index of suspicion for yeast-like agents other than Candida as agents of infection.
| ~ Acknowledgement|| |
The authors wish to thank Dr. M. R. Shivaprakash, Professor, Centre of Advanced Research in Medical Mycology, NCCPF, PGI-Chandigarh for confirming the isolate as Prototheca zopfii.
| ~ References|| |
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[Figure 1], [Figure 2], [Figure 3]