Streptococcus And Enterococcus

CATEGORIES OF NECROTIZING FASCIITIS
Type	Description
1	Polymicrobial infection (aerobic & anaerobic)
2	Consist of Group A Streptococci
3	Clostridial myonecrosis
Saltwater Necrotizing Fasciitis	Caused by Vibrio spp

S. pyogenes
Virulence Factor
M Protein	Antiphagocytic
Protein F	Fibronectin binding protein
Hyaluronic acid	Capsule prevents opsonization
Streptolysin O	O2 labile antigenic subsurface hemolysis
Streptolysin S	O2 stable non antigenic surface hemolysis
Streptokinase	Thrombolytic drug, fibrinolysis
Hyaluronidase( Duran- Reynal Factor )	Spreading factor
Erythrogenic Toxins (Streptococcal Pyrogenic Exotoxins)	SPEs A, B, C, F A – Scarlet Fever & Toxic shock sydrome
Disease Association / Characteristics (S. pyogenes) Necrotizing fasciitis / galloping gangrene Erysipelas (St. Anthony’s Fire) Impetigo Puerperal Sepsis Childbed Fever Scarlet Fever Poststreptococcal acute glomerulonephritis (Bright’s Disease)
S. agalactiae
Virulence Factor Sialic acid Critical virulence determinant Disease Association / Characteristics (S. pyogenes) Meningitis obstetric complications mastitis in cattles
S. pneumoniae
Virulence Factor Capsular polysaccharide Serotypes 1, 2, 3 – common cause of lobar pneumonia Disease Association / Characteristics (S. pneumoniae) Meningitis lobar pneumonia otitis media sinusitis bacteremia 2° atypical HUS

Enterococci
cytolysin Capable of producing pseudoperoxidase reaction (weak bubbling)
Viridans Streptococci
Common cause of subacute bacterial endocarditis Gingivitis Dental caries (S. mutans)
S. bovis group (S. gallolyticus subsp. Gallolyticus)
Associated with gastrointestinal carcinoma (colorectal tumors)

Test for Streptococci
Bacitracin Disk Test / Taxo A (0.04 U)	Differentiates S. pyogenes from other Beta hemolytic groups Result: Group C and G are susceptible
Sulfamethoxazole & Trimethoprim (SXT) test	Result: Group B – resistant to SXT Group C – sensitive to SXT
Pyrrolidonyl Arylamidase (PYR) test	More specific than bacitracin test S. pyogenes is the only Beta-hemolytic strep that is positive.
CAMP (Christie, Atkins, Munch-Petersen) test	Used to differentiate S. agalactiae from other Beta-hemolytic streptococci. Result: (+) arrowhead / bowtie-shaped Beta-hemolysis.
Hippurate Hydrolysis Test	Used to differentiate S. agalactiae from other Beta-hemolytic streptococci. Result: (+) purple color
Dick’s Test	Skin test for Scarlet fever
Schultz-Charlton Test	Immunity test for Scarlet fever
Neufeld-quellung test	Capsular swelling test for S. pneumoniae & other bacteria that has capsule.
Francis Skin Test	Detection of presence of antibodies against pneumococci.
Bile solubility test	Evaluates the ability of S. pneumoniae to lyse in the presence of bile salt.