Medical Microbiology

260 4 BacteriaasHumanPathogens

Epidemiologyandprevention.Actinomycosesoccursporadicallyworld-

wide.Averagemorbidity(incidence)levelsarebetween2.5andfivecases

per 100000 inhabitantsperyear.Menareinfectedtwiceasoftenaswomen.

Prophylacticconsiderationsareirrelevantduetotheendogenousnatureof

actinomycetesinfections.

OtherGram-PositiveRodBacteria....................

Table4. 3 listsbacteriathatarerarelyinvolvedininfectionsandnormallyin-

fectonlypersonswithdefectiveimmunedefenses.Recentyearshaveseen

considerablechangesintheirclassificationandnomenclature—stillanon-

goingprocess.Manyofthesebacteriaarepartofthenormaldermalandmu-

cosalflora.Theyarefrequentlyfoundinsampledmaterialsascontaminants,

butalsooccasionallycauseinfections.Someofthesebacteriaaredesignated

bycollectivetermssuchas“diphtheroidrods”or“coryneformbacteria.”

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Kayser, Medical Microbiology © 2005 Thieme