232 4 BacteriaasHumanPathogens&Leukocidindamagesmicrophagesandmacrophagesbydegranulation.
&Exfoliatinsareresponsibleforaformofepidermolysis.
&Foodpoisoningsymptomscanbecausedbyeightserologicallydifferen-
tiatedenterotoxins(A-E,H,G,andI).Theseproteins(MW: 35 kDa)arenot
inactivatedbyheatingto 1008 Cfor 15 – 30 minutes.Staphylococcusenterotox-
insaresuperantigens(seep. 7 2).
&Toxicshocksyndrometoxin-1(TSST-1)isproducedbyabout 1 %of
Staphylococcusstrains.TSST-1isasuperantigenthatinducesclonalexpansion
ofmanyTlymphocytetypes(about 10 %),leadingtomassiveproductionof
cytokines,whichthengiverisetotheclinicalsymptomsoftoxicshock.
Pathogenesisandclinicalpictures.Thepathogenesisandsymptomsof
S.aureusinfectionstakeoneofthreedistinctcourses:
&Invasiveinfections.Inthistypeofinfection,thepathogenstendtoremain
insituafterpenetratingthroughthedermaormucosaandtocauselocalin-
fectionscharacterizedbypurulence.Examplesincludefuruncles(Fig.4. 2 ),
carbuncles,woundinfections,sinusitis,otitismedia,andmastitispuerperalis.
Otherkindsofinvasiveinfectionincludepostoperativeorposttraumaticos-
titis/osteomyelitis,endocarditisfollowingheartsurgery(especiallyvalve
replacement),postinfluenzapneumonia,andsepsisinimmunocompromised
patients.S.aureusandE.coliareresponsibleforapproximatelyequalshares
ofnearlyhalfofallcasesofinpatientsepsis.
Inertforeignbodies(seep. 158 forexamples)canbecolonizedbyS.aur-
eus.Colonizationbeginswithspecificbindingofthestaphylococci,bymeans
ofcellwall-associatedadhesionproteins,tofibrinogenorfibronectincover-
ingtheforeignbody,resultinginabiofilmthatmayfunctionasafocusof
infection.MultipleFuruncles
Fig.4. 2 Furunclesinapa-
tientwithtype 2 diabetes
mellitus.4
Kayser, Medical Microbiology © 2005 Thieme