Incidence and risk factors for microbial keratitis.docx
- 文档编号:30192618
- 上传时间:2023-08-07
- 格式:DOCX
- 页数:15
- 大小:37.19KB
Incidence and risk factors for microbial keratitis.docx
《Incidence and risk factors for microbial keratitis.docx》由会员分享,可在线阅读,更多相关《Incidence and risk factors for microbial keratitis.docx(15页珍藏版)》请在冰豆网上搜索。
Incidenceandriskfactorsformicrobialkeratitis
ClinicalStudy
Eye(2002)16,608–618.doi:
10.1038/sj.eye.6700151
IncidenceandriskfactorsformicrobialkeratitisinHongKong:
comparisonwithEuropeandNorthAmerica
DSC Lam1,E Houang2,DSP Fan1,D Lyon2,D Seal3andE Wong4theHongKongMicrobialKeratitisStudyGroup
1DepartmentofOphthalmology&VisualSciencesPrinceofWalesandHongKongEyeHospitalsTheChineseUniversityofHongKong,HongKongPeople’sRepublicofChina
2DepartmentofMicrobiologyPrinceofWalesandHongKongEyeHospitalsTheChineseUniversityofHongKongHongKongPeople’sRepublicofChina
3AppliedVisionResearchCentreCityUniversityNorthamptonSquareLondonEC1V0HB,UK
4CenterforClinicalTrialsandEpidemiologicalResearchPrinceofWalesandHongKongEyeHospitalsTheChineseUniversityofHongKongHongKongPeople’sRepublicofChina
Correspondence:
ProfessorDSCLam,Tel:
(852)27623157Fax:
(852)21941369E-mail:
dennislam@cuhk.edu.hk
Topofpage
Abstract
Purpose Toestablishtheincidence,etiologyandriskfactorsformicrobialkeratitis(MK)inHongKong.
Methods Twohundredandtwenty-threenewcasesofpresumedMKwererecruitedoveraperiodof17monthsandcomprehensivemicrobiologicstudiesperformed.Anestedcase-controlstudywaspursuedforpatientswearingcontactlenses(CLW)todetermineriskfactorsforMKwithregardstotypesofCLWandhygienepractice.
Results Ofthe223patientsrecruited,59(26%)worecontactlenses.Cornealscrapesyieldedpositiveculturesfrom77patients(35%overall,56non-CLW,21CLW).TwohundredandsixCLWvolunteerswererecruitedtoparticipateinthecase-controlstudy,ofwhom135werematchedwith45CLWpatients.TheannualincidenceofMKwas0.63per10 000populationand3.4per10 000CLWwithratesfordaily,extendedandrigidlenswearof3.09,9.30and0.44per10 000CLWrespectively.Pseudomonasaeruginosawasthedominantbacterialpathogen.SixcasesofAcanthamoebakeratitisoccurred,fiveinCLW(incidence0.33per10 000CLW)andonefollowingcornealabrasion.Non-CLWdevelopedMKatapeakageof73,whichis10yearsyoungerthanexpectedforScotlandandUSA.
Conclusions PreviousocularsurfacediseaseandtraumawerethemainriskfactorsforMKinHongKong.CLWappearsatleastassafeasthatfoundinScotlandandtheUSA.AcanthamoebakeratitiswasdetectedbutwithanincidenceratefivetimeslowerthanScotland.FactorspredisposinghydrogelCLWstoMK,thatwerestatisticallysignificant,includedovernightwear,poorhygieneandsmoking.
Keywords:
microbialkeratitis;incidence;contactlens;riskfactors
Topofpage
Introduction
Ulcerativeandnon-ulcerativekeratitisduetoinfectionisapotentiallyblindingconditionthatisgenerallyonlyfoundineyeswithapredisposingelement.Contactlens(CL)wearisrecognizedasanincreasinglycommonriskfactorinotherwisehealthyeyes.1,2,3WhennotassociatedwithCLuse,itmaybediagnosedinpatientsofallagegroupsandtraumamaybeapredisposingfactor.WiththegrowthoftheCLuserpopulationsincethe1980s,thisfactorhasincreasedastheprimarypredisposingcauseformicrobialkeratitis(MK)intheUSAbutnotforScotlandandEngland.2,3Riskfactorssuchasextendedwearofthelens,especiallysleepingwiththelensintheeye,havebeendescribed4,5buthaveneverbeeninvestigatedinasubtropicalFarEastclimate.
Microbialkeratitishasbeenreportedduetoinfectionwithawiderangeoforganisms.Thereareregionalvariationsinthepredominanceofdifferentmicrobes,reflectingdifferentpatientpopulationsandclimaticeffects.Fungiareimportantinthetropicalregions,suchasSouthIndiaandGhana.6,7AcanthamoebahasbeenidentifiedamongCLrelatedinfectionsinmanypartsoftheworld.8
ThereislittleinformationonMKand/orCL-relatedinfectionsinAsia,althoughthenumberofCLwearersisexpectedtoincreaserapidly,particularlyamongtheyoung.ThisisespeciallylikelyinChinawheretheprevalenceofmyopiaisonarisingtrend.MKcausedbyunusualpathogensrequiresspecificandoftenexpensivediagnosticmethodsandtherapies.Acost-effectiveapproachinthediagnosis,managementandpreventionofthisconditionisonlypossiblewhentheincidence,relativeimportanceofdifferentmicrobialagentsandpredisposingfactorsareknown.ThecauseofsuchinfectionhasneverbeenfullyinvestigatedinSouthChina,inparticularinthesemi-tropicalurbanclimateofHongKong.
Topofpage
Materialsandmethods
AprospectivestudyofMKwasconductedbetweenApril1997andAugust1998withpatientsfromthetwohospitalswithEyeUnits—HongKongEyeHospital(HKEH)andthePrinceofWalesHospital(PWH)—servingourterritoryofKowloonandNewTerritoryEast,whopresentedwithsuchaclinicaldiagnosisandgaveoralconsent.MKwasdefinedastheclinicalpresentationof acornealstromalinfiltrate>1mm2usuallybutnotnecessarilywithanoverlyingepithelialdefect.Theonsetofpain,redness,blurredvision,foreignbodysensation,photophobia&dischargewereallrecordedaswasthevisualacuityonpresentation.Inaddition,thesizeoftheoverlyingdefectandthepositioninthecornea(axial,paraxialorperiphery)wererecorded.Typicalinflammatorykeratitissuchasmarginalkeratitis,andviralkeratitisduetoherpesandadenoviruseswereexcluded.Riskfactorssuchasoculartrauma,previousocularsurfacedisease(OSD),contactlenswear(CLW)andhistory,applicationofsteroidorantibiotic(s)andhistoryofherpeticinfectionwererecordedonpresentation.Thecharacteristicsoftheulcer/infiltrate(sizeinsquaremm,shape,siteandanteriorchamberactivity)werenoted.
InordertoassesshowmanycasesofMK(excludingclassicalinflammatory,herpeticandadenovirusinfection)existedinHongKongprivatepractice,aquestionnairewassenttoallthe27privateophthalmologistsinourareaontwooccasionsduringthestudyperiod.Theywereaskedtoestimatethenumberofcasestheyhadseenandthenumbertheyhadreferredtothetwostudycentersintheprevious3months.AllHongKongophthalmologistsandtheHongKongOptometricAssociationwereinformedofthisstudyandaskedtohelpreferpatientswithMKthatcouldbeconsideredduetobacteria,fungioramoebaetooneofthetwohospitalsmentionedaboveforinvestigationandtreatment.
Usingpreservative-freeamethocaineeyedropsforlocalanesthesia,cornealscrapingswereperformedinallcaseswithaKimuraspatula.MicroscopywasperformedonGram-stainedsmearsofthecornealsample.Inoculationofbloodandchocolateagarsandthioglycolatebrothforbacteria,Sabouraud’sagarforfungiandnon-nutrientPage’ssalineagarforAcanthamoebawascarriedoutatthetimeoftheprocedure.Incubationtookplaceat37°Cfor48 hforbacteria,1weekforNocardiaand3weeksforfungi.Cultureplateswereexaminedusingroutinelaboratorytechniques.CultureplatesforAcanthamoebawereincubatedat30°C,wrappedinplasticbags,andexaminedintermittentlyforupto4weeksforthepresenceofcharacteristicdouble-walledstar-shapedcysts.ThiswaspreciselythesamemethodasthatusedfortheScottishCohortStudy.2
TheprevalenceofCLWinHongKonghasbeeninvestigatedbyChoetalandrecordedas6%with13%wearingrigidlenses.9Thepopulationbyagegroupforourareain1998wasprovidedbytheCensusandStatisticsDepartment,HongKongSpecialAdministrativeRegion.Thiscensusrecordedatotalof2 489 701persons,with2 048 630overtheageof15.Thislatterfigurewasusedasthereferencenumberforthetotalpopulationwhocouldbewearingcontactlenses.
TodeterminetheriskfactorsforCL-relatedMK,anestedcasecontrolstudywascarriedoutbyrecruiting206asymptomaticCLWvolunteerswithoralconsent.Onehundredandthirty-fivematchedourCLWpatientsforage(<25,26–35,36–45,and>45),sex(maleorfemale)andeducationalstatus(graduate/non-graduate).Onehundredandtwentyofthese135controlswerecommunity-basedwith102comingfromourLASIK(Laserin-situkeratomileusis)Clinic,12fromtheEyeScreening2000ClinicandsixfromKowloonopticalpractices(withthehelpoftheHongKongOptometricAssociation).Fifteenmatchedcontrolswerehospital-basedlens-wearingasymptomaticstaffrecruitedatPWH.These135CLWvolunteerswerenotknowntorepresentanyspecificbias.Theresearchassistantface-to-faceinterviewedboththe45CLWpatientsand135volunteercontrolsusingthesamequestionnairestoestablishtheirtypesofCLWandhygienepractice.Questionsincludedthedurationoftimeofuseanduseinsleepduringdaytimeornighttime.
Forpatientandmatchedcontrolgroups,potentialriskfactorssuchasextendedwearofthelenswereevaluatedfortheirassociationwithMKbyunivariateandmultivariateconditionallogisticregressionanalyses.10Allriskfactorswerefirstassessedindividually,andmatchedoddsratios,thecorresponding95percentconfidenceintervalsandPvalueswerecalculated.RiskfactorswithP<0.25wereanalyzedbymultivariateanalysis10usingaforwardstepwiseselectionstrategy.Ingeneral,theprocessaddedthemostsignificantriskfactor(ietheonethatwouldresultinthelargestlikelihoodratiostatistic)tothemodelateachstep,andwouldcontinueuntilnoriskfactornotinthemodelmadeasignificant(P<0.05)contribution.WhenevertwoormorepotentialriskfactorswerehighlycorrelatedorP-valuesweresimilar,thefactorthatwasthemoreclinicallyorbiologicallyimportantwasselectedforentry.AnalyseswereperformedusingtheLogXactlogisticregressionsoftwarefeaturingexactmethods,version1.3(CYTELSoftwareCorporation,Cambridge,MA,USA).
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- Incidence and risk factors for microbial keratitis
链接地址:https://www.bdocx.com/doc/30192618.html