Medical Microbiology

Neisseria,Moraxella,andAcinetobacter 273

affectingtheimmunedefenses.Monoinfectionsaretherule.Thereareno

typicalclinicalsymptoms.Mostcasesofinfectioninvolvepyogenicinflam-

mationswithcentralnecroses.Thefollowingtypeshavebeendescribed:pul-

monarynocardioses(bronchialpneumonia,pulmonaryabscess),systemic

nocardioses(sepsis,cerebralabscess,abscessesinthekidneysandmuscu-

lature),andsurfacenocardioses(cutaneousandsubcutaneousabscesses,

lymphocutaneoussyndrome).

Actinomycetomasaretumorlikeprocessesaffectingtheextremities,includ-

ingbone.AnexampleofsuchaninfectionisMadurafoot,causedbyNocardia

species,therelatedspeciesActinomaduramadurae,andStreptomycessoma-

liensis.Fungi(p.355)canalsobeacausalfactorinthisclinicalpicture.

Diagnosis.Detectionofthepathogenbymeansofmicroscopyandculturing

techniquesisrequiredinmaterialsvaryingwiththespecificdisease.Dueto

thelonggenerationtimeofthesespecies,cultureshavetobeincubatedforat

leastoneweek.Preciseidentificationtodifferentiatepathogenicandapatho-

genicspeciesisdesirable,butdifficult.

Therapy.Theanti-infectiveagentsofchoicearesulfonamidesandcotrimox-

azole.Surgerymayberequired.

Epidemiologyandprevention.Nocardiosesarerareinfections.Annualinci-

dencelevelsrangefromabout0.5to 1 caseper 1000000 inhabitants.The

pathogens,whicharepresentinthenaturalenvironment,arecarriedbydust

tosusceptiblepatients.Therearenopracticableprophylacticmeasures.

Neisseria,Moraxella,andAcinetobacter...........................

&NeisseriaareGram-negative,aerobiccoccithatareoftenarrangedinpairs.

Theyaretypicalmucosalparasitesthatdierapidlyoutsidethehumanorgan-

ism.Culturingonenrichednutrientmediumsisreadilyfeasible.

Neisseriagonorrheaeisthepathogenresponsibleforgonorrhea(“clap”).

Infectionresultsfromsexualintercourse.Theorganismsadheretocellsofthe

urogenitaltractbymeansofattachmentpiliandtheproteinOpa,penetrate

intotheorganismusingparasite-directedendocytosisandcauseapyogenic

infection,mainlyoftheurogenitalepithelium.Aninfectionisdiagnosed

mainlybymeansofmicroscopyandculturingofpurulentsecretions.The

therapeuticofchoiceispenicillinG.Alternativesforuseagainstpenicillin-

ase-positivegonococciincludethird-generationcephalosporinsand4-quino-

lones.

N.meningitidisisaparasiteofthenasopharyngealmucosa.Thesemenin-

gococcicausemeningitisandsepsis.Diagnosisinvolvesdetectionofthe

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Kayser, Medical Microbiology © 2005 Thieme