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IntroductionIntroduction
Pyogenic pathogens - nonmotile, catalase negative, Gram positive cocci in chains
ClassificationClassification
Hemolysis on blood agar plates
Cell wall group-specific Cell wall group-specific substance substance
S pyogenes( group A)S pyogenes( group A)S agalactiae( group B)S agalactiae( group B)Enterococci( group D)Enterococci( group D)S pneumoniaeS pneumoniaeViridans streptococciViridans streptococcipeptostreptococcuspeptostreptococcus
BACKGROUND
Group A beta-hemolytic streptococci (Streptococcus pyogenes) is one of the most commonly encountered pathogens in humans.
Streptococcus Streptococcus pyogenespyogenes
SpecimensSpecimens
SmearsSmears
CultureCulture
Biochemical testBiochemical test
PYR testPYR test L-pyrrolidonyl-L-pyrrolidonyl-
ß-ß-naphthylamidenaphthylamide
dimethylaminodimethylaminocinnamaldehycinnamaldehydede
Streptococcus agalactiaeGroup B
Chronic bovine mastitis promoted by milking machines slowly progressing inflammation, fibrosis fibrin plugs in smaller milk ducts: loss of milk-
producing capacity (agalactia) Neonatal meningitis in humans
early onset septicemia (≈ 15% of all neonatal septicemias)
late onset: purulent meningitis (average 4.8 weeks after birth)
5 - 10 % of pregnant women are reproductive tract carriers
Most infection in newbornsMost infection in newborns Asymptomatic colonization of the upper Asymptomatic colonization of the upper
respiratory and genitourinary tractrespiratory and genitourinary tract
Streptococcus Streptococcus agalactiaeagalactiae
Asymptomatic colonization of the Asymptomatic colonization of the upper respiratory and genitourinary upper respiratory and genitourinary tracttract
Most infection in newbornsMost infection in newborns
Streptococcus Streptococcus pneumoniaepneumoniae
Gram positive Gram positive diplococci( lancet-diplococci( lancet-shaped)shaped)
Possessing a capsulePossessing a capsule
Normal inhabitants of Normal inhabitants of the upper respiratory the upper respiratory tracttract
Viridans Viridans streptococcistreptococci
Found in the upper respiratory tract
Endocarditis 30-40% of cases due
to viridans viridans streptococci
EnterococciEnterococci Part of normal enteric floraPart of normal enteric flora Important species Important species
1.1. Enterococcus faecalisEnterococcus faecalis
2.2. Enterococcus faeciumEnterococcus faecium Grow in the 10˚ C to 45˚ CGrow in the 10˚ C to 45˚ C Typically non hemolyticTypically non hemolytic Grow in the presence of 6.5 % Grow in the presence of 6.5 %
NaClNaCl Hydrolyze esculinHydrolyze esculin