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INTRODUCTION

Onychomycosis refers to fungal infection of thenail that results in thickening, discolouration,disfiguring and splitting of finger and toe nails.It is frequently caused by dermatophytes: butnow, non-dermatophytic moulds are known toaccount for 2%-12% of the nail infections.1

Fungal infections may occur following traumaor wound contamination.2 In many casescontinuous exposure to physical and chemicalaggressions facilitates penetration by differentfungal species including the less pathogenicspecies.3 Majority of fungi which are implicatedin human infections are saprophytic and are,present in soil and environment.4 Fusariuminfections in human are usually opportunisticbut the fungus sometimes infects healthypersons causing onychomycosis andkeratomycosis. Disseminated fuseriasis is seenin high risk patients with haematological

cancers, organ transplant recipients and in burnpatients.5,6 Here we report 5 cases withonychomycosis caused by a rare species ofFusarium, namely, Fusarium dimerum.

CASE REPORTS

Five patients presented to Dermatology out-patients department (OPD) between June-September months at our hospital in Kolkata,West Bengal. All were from suburban area ofKolkata. Sample of nails (nail clippings andscrapings) previously cleaned with 70% alcoholwere collected using a sterile scalpel blade fromall of them. Direct microscopy with 40%potassium hydroxide (KOH) wet mount andinoculation onto both Sabourauds dextrose agar(SDA) and SDA with chloramphenicol (SDCA)followed by incubation at 25 p C were perfor-med to isolate and identify the pathogenic fungi.Their details are shown in Table 1, Figure 1.

Case Report:Onychomycosis caused by Fusarium dimerum

Reena Ray, 1 Mallika Ghosh,2 Mitali Chatterjee,1 Nibedita Chatterjee,1 Manas Banerjee,1

Department of 1Microbiology, R.G. Kar Medical College, Kolkata and Research officer,NICED, Kolkata

ABSTRACTFusraium is a non-dermatophytic hyaline mould found as soil saprophytes and plant pathogens. Human infections areprobably a result of various precipitating predisposing factors of impaired immune status. Immunocompetent individualsof older age group are also vulnerable to various unassuming saprophytic and plant pathogen. We report 5 cases withonychomycosis caused by a rare species of Fusarium, namely, Fusarium dimerum. Fusarium is known to cause avariety of infections like keratitis, eumycetoma, onychomycosis, skin lesions and sometimes disseminated infection inindividuals with impaired immunity. Hence it is of utmost importance to identify this newly emerging fungal pathogencorrectly and institute appropriate treatment to control human infections at the earliest so that disseminated infectionscan be avoided.

Key words: Fuserium dimerum, Onychomycosis, Immunocompetent individualsRay R, Ghosh M, Chatterjee M, Chatterjee N, Banerjee M. Onychomycosis caused by Fusarium dimerum. J Clin Sci Res2016;5:44-8. DOI: http://dx.doi.org/10.15380/2277-5706.JCSR.14.062.

Corresponding author: Dr Reena Ray,Assistant Professor, Department ofMicrobiology, R.G. Kar Medical College andHospital, Kolkata, India.e-mail: ghoshreena@hotmail.com

Received: October 27,2014; Revised manuscript received: April 22, 2015; Accepted:June 01, 2015.

Online accesshttp://svimstpt.ap.nic.in/jcsr/jan-mar16_files/2cr16.pdf

DOI: http://dx.doi.org/10.15380/2277-5706.JCSR.14.062

Onychomycosis caused by Fusarium dimerum Reena Ray et al

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Onychomycosis caused by Fusarium dimerum Reena Ray et alTa

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46

Direct microscopy of 40% KOH wet mountrevealed hyaline septate branched hyphae.Culture on SDA and SDCA grew white floccosewith aerial mycelia fringes on obverse (Figure2) but on reverse the colour of the growth wassalmon to orangish brown which turned to darkbrown on aging of culture (Figure 3).Microscopic examination of the mould byteased mount in lactophenol cotton blue(LPCB) preparation showed septate andbranched hyaline hyphae with many sickleshaped macroconidia which werecharacteristically smaller in size in comparisonto other species and had 0-3 septa (Figure 4).Macroconidiophore were short, simple andusually unbranched with monophialides.Microconidia were significantly absent andplenty of chlamydoconidia were noticed in oldcultures (Figure 5). The above macro andmicroscopic picture was suggest ive ofFusarium dimerum.7

These patients were prescribed oralitraconazole (400mg/day in divided doses)thrice-a-week for three weeks. The course wasagain repeated after a gap of 1 week. Theduration of treatment for lesions on finger nailwas for 3-4 months but for involvement of toenails, duration was 8-9 months. The patientswere followed-up in the Dermatology OPDafter 4 weeks. All patients responded well totreatment.

DISCUSSION

New opportunistic pathogens have nowemerged as a cause of life threatening infectionsworldwide sometimes. Extensive literaturesearch reveals that Fusarium dimerum thoughappear as a rare species are notorious in causingvarious human infections like post operativeendopthalmitis,8 peritonitis9 and cutaneousfusariosis in a patient with acute myeloblasticleukaemia (AML).10 But there is nodocumented report of Fusarium dimerum as acausative agent of onychomycosis in theliterature till date to the best of our knowledge.

In human with normal immune system fusarialinfections may occur only in nails and in cornea.Onychomycosis caused by fusarial speciesusually involves the toe nails and enter the bodythrough trauma.11 This was noted in all casesmentioned above and the likely route of entrywas probably due to unnoticed trauma as mostlythey walk on barefoot. Fuserial onychomycosisis seen as white superficial lesion (WSO) inimmunocompetent patients. Rarely, proximalsubungual onychomycosis (PSO) caused byFuserium species has been reported.12 Thefrequently isolated species of Fusarium causingonychomycosis are namely Fusarium solaniand Fusarium oxysporum. We have alsoisolated these Fusarium species in severaloccasions from onychomycosis cases in ourlaboratory. Fusarium proliferatum is anuncommon aetiological agent causingonychomycosis. We have isolated Fusariumdimerum in 5 patients with onychomycosiswhich are clinically typed as WSO and PSO.All of them were from suburban area of Kolkataand presented between June to Septembermonths which may signify the seasonalinfluence. These lesions require long termtreatment only for its cosmetic effect. Inimmunocompromised patients they can causedisseminated infections with poor response toantifungal agents. Among five patients ofonychomycosis, two patients were sufferingfrom diabetes mellitus. Considering theirimmune status they should be treated promptly.In immunocompromised individuals onycho-mycosis may act as a portal of entry for lifethreatening systemic infect ions.6 Theseinfections require proper diagnosis and earlytreatment.

Hence, severely immunocompromised patientswith skin, nail or other tissue breakdowncondit ions should avoid exposure toenvironmental sources of Fusarium species liketap water, soil which may be potentiallycontaminated with Fusarium species. Infections

Onychomycosis caused by Fusarium dimerum Reena Ray et al

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Onychomycosis caused by Fusarium dimerum Reena Ray et al

Figure 2: Colony morphology of Fusarium dimerumon SDCA (obverse)

Figure 3: Colony morphology of Fusarium dimerumon SDCA (reverse)

Figure 4: Photomicrograph showing Fuserium dimerumshowing plenty of macroconidia with one /two septa(Lacto phenol cotton blue, 400)

Figure 5: Photomicrograph showing abundantchlamydoconidia are seen in old culture (Lactophenolcotton blue, 400)

Figure 1: Clinical photograph (case 3) showing whitesuperficial onychomycosis

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Onychomycosis caused by Fusarium dimerum Reena Ray et al

due to Fuserium involving skin and nail shouldbe thoroughly investigated13 in the laboratorydown to species level before discarding themas laboratory contaminants. Subsequentlyreporting the same to the treating clinicians isa must keeping in mind the invasive potential14

of the emerging pathogen. This can bring downmortality with appropriate treatmentparticularly among agricultural workers andlabourers15 and also for people who are at riskof acquiring this infection.

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onychomycosis. Clin Dermatol 2010;28:160-3.2. Yu WK.Fusarium infection. Hong Kong

DermatolVenerol Bull 2001;9:71-4.3. Jandial S, Sumbali G. Fusarial onychomycosis

among gardeners: a report of two cases. Indian JDermatol Venereol Leprol 2012;78:229.

4. Kuruvilla TS, Dias M. Fuserium Solani: acausative agent of skin and nail infections. IndianJ Dermatol 2012;57:308-9.

5. Boutati EI, Anaissie EJ. Fusarium, a significantemerging pathogen in patients withwith hematologic malignancy: ten years’ experience ata cancer center and implications for management.Blood 1997;90:999-1008.

6. Krcmery V Jr, Jesenska Z, Spanik S, GyarfasJ, Nogova J, Botek R, et al. Fungemia due toFusarium spp. in cancer patients. J Hosp Infect1997;36:223-8

7. Kwon-Chung KJ, Bennett JE. Medical mycology.Philadelphia, London: Lea and Febiger, 1992.

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10. Collado C, Medina L, Zorraquino A, BaezaT, Ferrer C, Plazas J, et al. Cutaneous fusariosisby a species of the Fusarium dimerum speciescomplex in a patient with acute myeloblasticleukaemia. Rev Iberoam Micol 2013;30:119-21.

11. Nucci M, Anaissie E. Cutaneous infection byFusarium species in healthy andimmunocompromised hosts: implications fordiagnosis and management. Clin Infect Dis2002;35:909-20.

12. Baran R, Tosti A, Piraccini BM. Uncommonclinical patterns of Fusarium nail infection: reportof three cases. Br J Dermatol 1997;136:424-7.

13. Calado NB, Sousa F Jr, Gomes NO, CardosoFR, Zaror LC, Milan EP. Fusarium nail and skininfection: a report of eight cases from Natal, Brazil.Mycopathologia 2006;161:27-31.

14. Godoy P, Nunes E, Silva V, Tomimori-YamashitaJ, Zaror L, Fischman O. Onychomycosis causedby Fusarium solani and Fusarium oxysporum inSao Paulo, Brazil. Mycopathologia 2004;157:287-90.

15. Veer P, Patwardhan NS, Damle AS. Study ofonychomycosis: prevailing fungi and pattern ofinfection. Indian J Med Microbiol 2007;25:53-6.