Fusarium solani keratitis: role of antifungal susceptibility testing and identification to the species level for proper management

brazjinfectdis2019;23(3):197–199

w w w . e l s e v i e r . c o m / l o c a t e / b j i d

The

Brazilian

Journal

of

INFECTIOUS

DISEASES

Case

report

Fusarium

solani

keratitis:

role

of

antifungal

susceptibility

testing

and

identification

to

the

species

level

for

proper

management

Priscila

Dallé

Rosa

_,

_Karla

_Sheid

_,

_Claudete

_Locatelli

_,

_Diane

_Marinho

_,

Luciano

Goldani

a_{UniversidadeFederaldoRioGrandedoSul,ProgramadePós-Graduac¸ãoemMedicina:CiênciasMédicas,RioGrandedoSul,RS,Brazil}

b_{HospitaldeClínicasdePortoAlegre,Servic¸odeOftalmologia,PortoAlegre,RS,Brazil}

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Articlehistory:

Received1May2019 Accepted9May2019 Availableonline23May2019

Keywords:

Keratitis Cornealulcer

Fusariumsolani

Antifungalagentsresistance

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WereportapatientwithfungalkeratitiscausedbyamultiresistantFusariumsolaniina ter-tiarycarehospitallocatedinsouthernBrazil.A55-year-oldmanwithahistoryofocular traumapresentedwithkeratitisinlefteye.Thepatienthasacomplicatedclinicalcourse andfailedtorespondtolocalandsystemicantifungaltreatment,andrequiredeye enu-cleation.Despitemultipletopical,intraocularandsystemicantifungaltreatments,hyphal infiltrationpersistedinthecornealtransplantcausingcontinuousrecurrences.Thecultures ofcornealbiopsyscrapingswerepositiveforFusariumspp.Theorganismwasidentifiedto specieslevelbymulti-locussequencingfortranslationelongationfactor1alpha(EF-1␣), andRNApolymeraseIIsubunit(RPB2).Invitroantifungalsusceptibilitytestingofthe iso-latebythebrothmicrodilutionmethod,accordingtoCLSIM38-A2,disclosedsusceptibility tonatamycinandresistancetoamphotericinB,voriconazole,itraconazoleandfluconazole. Consideringpreviousunsuccessfulantifungaltreatmentsduetomultipledrugresistance, theeyewasenucleated.Ourcasereportillustratesthatmanagementoffungalkeratitis remainsatherapeuticchallenge.OptimaltreatmentforF.solaniinfectionhasnotyetbeen establishedandshouldincludesusceptibilitytestingfordifferentantifungalagents.

©2019SociedadeBrasileiradeInfectologia.PublishedbyElsevierEspa ˜na,S.L.U.Thisis anopenaccessarticleundertheCCBY-NC-NDlicense(http://creativecommons.org/ licenses/by-nc-nd/4.0/).

Fusariumkeratitisappearsasulcerativelesionsandisusually

managedusingtopicalantifungalmedications,occasionally integrated withsubconjunctival injections, although thera-peutic keratoplasty may be necessary for patients whose corneal infection persists.1 _{The species most commonly}

∗ _{Correspondingauthor.}

E-mailaddress:lgoldani@ufrgs.br(P.D.Rosa).

associatedwithhumaninfectionsisF.solani.Fusarium kerati-tismightprogresstodeepextensiveinfectionwithperforation andmalignant glaucoma,whichmightdestroytheeyeina fewweeks.Management ofFusarium keratitisisoften diffi-cultconsideringthatFusariumspeciesexhibitbroadresistance tothespectrumofantifungalscurrentlyavailable,including amphotericinB,azoles,echinocandins,andterbinafine,which typicallyshowhighMICsinvitrotesting.2

https://doi.org/10.1016/j.bjid.2019.05.002

1413-8670/©2019SociedadeBrasileiradeInfectologia.PublishedbyElsevierEspa ˜na,S.L.U.ThisisanopenaccessarticleundertheCC BY-NC-NDlicense(http://creativecommons.org/licenses/by-nc-nd/4.0/).

198

Fig.1–Opticalbiomicroscopyimageshowingadense temporalcornealulcerwithpoorlydefinededgesand3mm hypopyon.

We describe the clinical course and management of a patientwithsevereFusariumkeratitis.Thepatientfailedto respondtoantifungaltreatmentandrequiredenucleation sur-gicalprocedure.

A55-year-oldmanwithahistoryofoculartraumaonthe left eye10 daysago presentedwithkeratitisinleft eyefor ophthalmologicevaluation.Thepatienthadacorneal trans-plant for keratoconus on the left eye 32 years ago. After the ocular trauma, the patient developed a corneal ulcer, andhypopyon(Fig.1)despitetreatmentwithdailyeyedrops includingketorolac5mg/mLandgatifloxacin0.3%. Visualiza-tion by ocular ultrasound disclosed extensive involvement of anterior vitreous and lens. Cultures of corneal biopsy scrapings were performed. Samples were inoculated onto Sabouraud dextrose agar plates and incubated for 7 days at 25◦C. Macroscopically, the rapid growth cultures pre-sented a pale yellowish pigmentation on the reserve side oftheplate (Fig. 2A),andcottony colonyappearance with aerialwhitemyceliumatthesurfaceoftheplate(Fig.2B). Microscopicallythe culturerevealed septated hyphae, half-moon-shapedmacroconidium,andmicroconidia(Fig.2C).The funguswasidentifiedasFusariumsppbasedon morpholog-ical features. The morphological identification of Fusarium

couldbeconfirmed formultilocussequence typing (MLST). Thismethodisbasedontwo-locusDNAsequence-based typ-ingschemes,includingportionsofthetranslationelongation factor1␣(EF-1␣)andthesecond-largestsubunitofRNA poly-merase(RPB2).OurisolatewasidentifiedasFusarium solani

speciescomplex(FSSC),F.solanihaplotype5-n(NRRL32741).

Antifungal susceptibility testing was performed by broth microdilutionmethod,CLSIdocumentM38-A2.3_Thepatient

was initially treatedwith vancomycin and ceftazidimeeye drops, atropineandoralacetazolamide250mg.Inaddition, the patient underwent keratoplasty withanterior chamber washandintravitrealinjectionofvancomycin10mg/mL, cef-tazidime20mg/mLandamphotericinB0.1%.Duetothehigh suspicionofintraocularcommitment,thepatientunderwent a posteriorvitrectomy throughwithtemporary keratopros-thesisimplantsand underwenttreatmentwithintravenous voriconazole 200mgevery 12h and amphotericinB deoxy-cholate1mg/kgonceaday.Thefungalshowedsusceptibility tonatamycinwithMICvalueof2␮g/mL,andreduced sensitiv-itytovoriconazoleandamphotericinB,withhigherMICvalues of32and16␮g/mL,respectively.Resistancewasdemonstrated againstitraconazoleandfluconazole(>64␮g/mL).Considering thepoorvisualprognosisandthemultiresistantnatureofthe fungus,itwasdecidedtoevisceratethelefteye.

Globally, the FSSC is the most common pathogen that causes fungal keratitis.F. solaniisthepredominantspecies (foundinupto91%ofisolates)pathogenictotheeye.Most infectionshavebeenreportedinruralworkers,andthe infec-tionsareoftenprecededbytrauma.Thesedatasupportour findings,ourpatientwasafarmerwhosufferedtraumatohis lefteyeanddevelopedanaggressivefungalkeratitis.4

Considering the lower MICs for members of the FSSC, amphotericinBand voriconazoleare theantifungalagents ofchoicefortreatmentofFusariumkeratitis.However,these antifungal options were not effective for our patient.5 _In

fact, the in vitro antifungal test showed high MIC val-ues to almost all antifungal agents available, except for natamycin.Unfortunately,accesstothismedicationwasnot available. F. solani usually exhibit high MICs for flucona-zoleand itraconazole.Echinocandinsare notactiveagainst

Fusariumspp.Second-generationtriazolessuchas

posacona-zole appear to be promising for the treatment of fungal infections of the eye. In fact, posaconazole was shown to penetratethevitreoushumoraswellastheaqueoushumor in a patient witha F. solanikeratitis and endophthalmitis. Many studies have been publishedand consensushasnot been reachedon the best drugstotreat Fusariumkeratitis. The topical antifungal agent of choice in Fusarium kerati-tis isnatamycin(alsoknown aspimaricin)5%,but delayed diagnosis mayleadtoaninsufficientresponsebecause the penetrationofnatamycinthroughthecornealepitheliumis poor.Antifungaltestingandpreciseidentificationofspecies

of Fusarium contribute to the understanding of the

epi-demiology and guiding treatment of this difficult-to-treat infection.

brazj infect dis.2019;23(3):197–199

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Fig.2–Fusariumreverse(A)andsurfacecolony(B)onSDAcultureafter1weekofincubationat25◦C.MicroscopyofF.solani

lactophenolcotton-bluestainwithabundantmacroconidiaandellipsoidalmicroconidia(0–1-septate)observedby microcultivationina7-dayoldculture:Notetheconidiophoresandconidia(C),×400bar200␮m.

Disclosures

Theauthorsdeclarenoconflictofinterest.

Acknowledgments

ThisstudywassupportedinpartbyCNPq(BrazilianCoucilof Resarch).

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