Streptococcus

Front 1

Streptococcus

Back 1

GPC in pairs and chains. Catalase negative. Facultative anaerobes. Many alpha/gamma are normal flora in skin, respiratory, mucosal surfaces, and female genital tract.

Front 2

Hemolysis

Back 2

Strep produces hemolysins (ie. streptolysin O and S) which destroy RBCs and releases hgb into surrounding media.

Front 3

Streptococcus pyogenes

Back 3

Group A. Beta hemolytic zone of hemolysis > colony size. PYR positive. Susceptible to bacitracin (taxos A disk). Resistant to SXT. Has M protein.

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PYR

Back 4

The substrate combines with a color indicator to form a red rxn.

Front 5

Infections caused by S. pyogenes

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Bacterial pharyngitis (strep throat), impetigo (skin infection), rheumatic fever, glomerulonephritis, Scarlet fever (red rash), and necrotizing fasciitis

Front 6

Infections caused by S. agalactiae

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Neonatal sepsis, meningitis. Reason for routine testing of pregnant women at 35-37 wks.

Front 7

Streptococcus agalactiae

Back 7

Group B. Beta hemolytic zone < colony size. Resistant to SXT, PYR neg, Bacitracin resistant, CAMP test positive.

Front 8

CAMP

Back 8

A test to identify Group B β-streptococci based on their formation of CAMP factor that enlarges the area of hemolysis formed by β-hemolysin from Staph. aureus.

Front 9

Listeria

Back 9

Gram positive straight rod, tumbling motility, "umbrella" pattern of motility at RT. Causes meningitis in newborns. Mimics group B beta strep on BAP.

Front 10

Streptococcus viridans

Back 10

Alpha hemolytic. butterscotch smell, VP positive, Optochin resistant. Bile esculin negative. Associated w/ abscess formation.

Front 11

Streptococcus pneumoniae

Back 11

Alpha strep. Cocci in pairs, lancet shape, concave colonies, sometimes mucoid. Optochin sensitive.

Front 12

Enterococci

Back 12

Reacts w/ Lancefield group D. Positive for bile, esculin, 6.5% NaCl, and PYR.

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Enterococci virulence factors

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Can grow in extreme conditions. Causes UTI and endocarditis.

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Nutritionally Variant Streptococci (NVS)

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Do not grow on sheep blood agar. 90% PYR positive. Satellites around Staph colonies. More resistant to antibiotics.

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Antibiotic treatments for Strep.

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Glycopeptides: vancomycin
Aminoglycosides: gentamicin, streptomycin
-high level resistance

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Strep looking organism resistant to vancomycin

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Ie. NVS and Enterococcus.
Usually alpha hemolytic and looks like strep on BAP.
Lactobacillus (Gram positive rod confused w/ alpha strep, but resistant to vancomycin).

Front 17

Aerococcus

Back 17

GPC in groups, bile negative, PYR negative, 6.5% NaCl positive. A. viridans may be confused w/ enterococcus.

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Strep pathogens

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Group A, Group B, S. pneumoniae, Enterococcus

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Penicillin for most Strep

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Resistance rarely seen for Gp A and B. Increased resistance seen in S. pneumoniae (important to do antibiotic testing).