Medical Microbiology

34 1 GeneralAspectsofMedicalMicrobiology

pneumococcalvaccinationsarenotobligatoryinGermany,Austria,andSwit-

zerland(seewww.rki.de).Tosimplifytheapplicationofvaccines,licensed

combinationvaccinesmaybeusedwheneveranycomponentsofthecom-

binationareindicatedandthevaccine’sothercomponentsarenotcontrain-

dicated.Providersshouldconsultthemanufacturers’insertsfordetailedin-

formation.

Passiveimmunization.Thisvaccinationmethodinvolvesadministrationof

antibodiesproducedinadifferenthost.Inmostcases,homologous(human)

hyperimmunesera(obtainedfromconvalescentpatientsorpatientswith

multiplevaccinations)areused.Thepassiveimmunityobtainedbythis

methodislimitedtoafewweeks(ormonthsatmost).

PrinciplesofSterilizationandDisinfection

&Sterilizationisdefinedasthekillingorremovalofallmicroorganismsand

virusesfromanobjectorproduct.Disinfectionmeansrenderinganobject,

thehandsorskinfreeofpathogens.Thetermasepsiscoversallmeasures

aimingtopreventcontaminationofobjectsorwounds.Disinfectionandster-

ilizationmakesuseofbothphysicalandchemicalagents.Thekillingofmi-

croorganismswiththeseagentsisexponential.Ameasureoftheefficacyof

thisprocessistheDvalue(decimalreductiontime),whichexpressesthetime

requiredtoreducetheorganismcountby 90 %.Thesterilizationagentsof

choicearehotair(1 808 C, 30 minutes; 1608 C, 120 minutes)orsaturatedwater

vapor(1 218 C, 15 minutes,2.02! 105 Pa; 1348 C,threeminutes,3.03! 105 Pa).

Gammaraysorhigh-energyelectronsareusedinradiosterilizationatare-

commendeddoselevelof2.5! 104 Gy.

Disinfectionisusuallydonewithchemicalagents,themostimportantof

whicharealdehydes(formaldehyde),alcohols,phenols,halogens(I,Cl),

andsurfactants(detergents). &

TermsandGeneralIntroduction

Terms

Sterilizationisthekillingofallmicroorganismsandvirusesortheircomplete

eliminationfromamaterialwiththehighestpossiblelevelofcertainty.

Anobjectthathasbeensubjectedtoasterilizationprocess,thenpackaged

soastobecontamination-proof,isconsideredsterile.

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Kayser, Medical Microbiology © 2005 Thieme