Medical Microbiology

220 3 GeneralBacteriology

Table3. 9 OverviewoftheMedicallyMostImportantBacteria^1

Family

Genus,species

Characteristics Clinical

manifestations

Section 1 .Gram-positivecocci

Staphylococcaceae Cluster-formingcocci,

nonmotile;catalase-positive

Staphylococcusaureus Coagulase-positive,

yellow-pigmentedcolonies

Pyogenicinfections,

toxicoses

S.epidermidis Coagulase-negative,whitish

colonies,normalflora

Foreignbodyinfections

S.saprophyticus Coagulase-negative Urinarytractinfectionsin

youngwomen

Streptococcaceae Chain-formingcocciand

diplococci,nonmotile,

catalase-negative

Streptococcuspyogenes Chain-formingcocci,Lance-

fieldgroupA,b-hemolysis

Tonsillitis,scarletfever,

skininfections

S.pneumoniae Diplococci,nogroupantigen

present,a-hemolysis

Pneumonia,otitismedia,

sinusitis

S.agalactiae Chain-formingcocci,group

antigenB,b-hemolysis

Meningitis/sepsisin

neonates

“Enterococcaceae” Chain-formingcocciand

diplococci,a,b,orc-hemo-

lysis,groupantigenD,

catalase-negative

Partofthefloraof

intestinesofhumansand

animals

Enterococcusfaecalis

Enterococcusfaecium

Aesculin-positive,growth

in6.5%NaCl,pH9.6

Opportunistic

infections

Section2.Endospore-formingGram-positiverods

Bacillaceae Aerobicsoilbacteria

Bacillusanthracis Nonmotile,ubiquitous Anthrax

Clostridiaceae Anaerobicsoilbacteria

Clostridiumtetani Motile,anaerobic,tetanus

toxin(tetanospasmin)

Tetanus

(^1) (NomenclatureaccordingtoBergey’sManualofSystematicBacteriology, 2001 ,
Vol. 1 ,pp. 155 – 1 66.Namesinquotationmarksnotyetvalidated).
3
Kayser, Medical Microbiology © 2005 Thieme