Medical Microbiology

OpportunisticEnterobacteriaceae 295

OpportunisticEnterobacteriaceae..................................

ManyEnterobacteriaceaewithminimumpathogenicityareclassicopportu-

nists.The mostfrequentopportunistic infectionscausedbythemare:

urinarytractinfections,respiratorytractinfections,woundinfections,

Table4. 9 OverviewoftheMostImportantEnterobacteriaceaeThatCause

OpportunisticInfections

Bacterialspecies Properties

Escherichiacoli Seep.280ff.,p.292ff.

Citrobacterfreundii;C.divs.;

C.amalonaticus

CanusecitrateasitssolesourceofC;delayed

breakdownoflactose;nonmotile

Klebsiellapneumoniae;K.oxytoca

andothers

Lactose-positive;nonmotile;manystrainshavea

polysaccharidecapsule.Causeapprox. 10 %of

nosocomialinfections.Causativeorganismin

so-calledFriedla ̈nder’spneumoniainpredis-

posedpersons,especiallyinthepresenceof

chronicpulmonarydiseases.

Klebsiellaozaenae Causativepathogeninozena;atrophyofnasal

mucosa

Klebsiellarhinoscleromatis Causativepathogeninrhinoscleroma;

granulomainthenoseandpharynx

Enterobactercloace;E.aerogenes;

E.agglomerans;E.sakazakii,and

others

Lactose-positive;motile;frequentmultiple

resistancetoantibiotics

Serratiamarcescensandothers Lactose-positive;motile;frequentmultiple

resistancetoantibiotics,somestrainsproduce

redpigmentat 208 C

Proteusmirabilis

Proteusvulgaris

Lactose-negative;highlymotile;wanderson

surfaceofnutrientagar(swarming).Oantigens

OX-2,OX-19,andOX-KfromP.vulgarisare

identicaltorickettsiaeantigens.Forthisreason,

antibodiestorickettsiaewereformerlyidentified

usingthesestrains(Weil-Felixagglutinationtest)

Morganellamorganii Lactose-negative;frequentmultipleresistance

toantibiotics

Providenciarettgeri;P.stuartii Lactose-negative;frequentmultipleresistance

toantibiotics

4

Kayser, Medical Microbiology © 2005 Thieme