Investigating Fungal Outbreaks in the 21st Century

Publicattention hasbeendrawn torecent high-profile outbreaksofmycotic diseases,such asthoseoffungalmeningitis and otherinfectionslinkedtocontaminated steroids [1]andanout-breakofnecrotizing cutaneousmucormycosis linkedtoatornado [2].However,fungalout-breaksaremorecommon thanmostpeopleappreciate, and reports ofoutbreakscaused byunusual fungalpathogens areincreasing. TheMycoticDiseases BranchattheCentersforDis-easeControl and Prevention (CDC) investigates 3–6fungaloutbreaksperyear,manyofwhicharecausedbyrare fungiwith limiteddiagnostic and treatmentoptions. Thisisaconsiderableincrease fromthe 1990s,whenthe Branchinvestigated1–2hospital-based outbreaksperyear,generally caused byyeastandtracedtoasinglesource. Althoughthe exactreasons forthisin-creaseareunknown,theincreasednumberofpatients with impaired immune system mayhavecontributedtothistrend.Themajorityoffungaloutbreakscanbeattributedtoeitherenvironmentalexposureoracontaminatedproduct(Table1).Forexample,tworecentoutbreakswerelinkedtocontaminat-edmedications.In2012,twomedicationsproducedbyasinglecompoundingpharmacyinFlor-idawerecontaminatedwithFusariumsp.andBipolarissp.,respectively,shippedto15states,andinjectedintotheeyesofpatientsundergoingvitrectomies.Asaresult,47patientsdevelopedendophthalmitis,andmostlostvision[3].Inthe2012fungalmeningitisoutbreak,methylpred-nisoloneacetate(MPA)contaminatedwithExserohilumrostratumandseveralothermicroor-ganismswasshippedto23states,potentiallyexposingnearly14,000individualstothiscontaminatedmedication.Asaresult,752peopledevelopedmeningitis,arachnoiditis,orspinal/paraspinalabscesses,and64patientsdied,makingthisthedeadliestfungaloutbreaktodate[1].Environmentalexposureistheothercommoncauseoffungaloutbreaks[2,4].Forexample,arecentclusterofRhizopusdelemarinfectionsinachildren’shospitalinNewOrleanswaslinkedtocontaminatedlinens[4].Inthisoutbreak,fivechildrendiedfromcutaneousmucor-mycosis,andR.delemarwasisolatedfromlinens,linenshelves,andbinsatthehospital[4].Inanotherexample,13peopledevelopednecrotizingcutaneousmucormycosiscausedbyApophy-somycestrapeziformisafterreceivingpuncturewoundscausedbyflyingdebrisduringatornado[2].AlthoughA.trapeziformiswasnotrecoveredfromthelocalenvironment,wholegenomese-quencetyping(WGST)oftheisolatesshowedthatatleastthreedifferentstrainswereinvolved,suggestingenvironmentalexposure[2,5].Inaddition,manyotheroutbreaksandclusterscausedbydimorphicandotherfungalpathogenshavebeenlinkedtoenvironmentalexposure[6–8].