Lec 7 Flashcards
Habitat of S. pyogenes
Throat, skin
Habitat of S. agalactiae
Female genital tract
Habitat of S. dysgalactiae
Throat
Habitat of Enterococcus faecalis
Colon
Habitat of S. bovis
Colon
Habitat of S. pneumoniae
Throat
Complete destruction of erythrocytes with clearing of the blood around the bacterial growth
Beta hemolysis
Incomplete lysis of erythrocytes with reduction of hemoglobin and formation of green pigment
Alpha hemolysis
Nonhemolytic
Gamma hemolysis
Used to classify S. pneumoniae into more than 90 types
Capsular polysaccharides
Group B streptococci
S. agalactiae
Group A antigen
S. pyogenes
S. pyogenes is susceptible to?
Bacitracin
Spherical or ovoid cocci arranged in chains
Streptococcus pyogenes
Striking diplococcal appearance
Streptococcus pyogenes
Hair-like pili project through the capsule which consists of M. protein and covered with lipoteichoic acid
S. pyogenes
S. pyogenes culture
Discoid colonies
Size of a discoid colonies
1-2mm diameter
Streptococci grows best at what temperature?
37C
Grows under aerobic and anerobic conditions
Facultative anaerobs
Obligate anaerobs
Peptostreptococci
Organisms that produce much M protein, generally virulent
Matte colonies
Less M protein, less virulent
Glossy colonies
Major virulence factor of S. pyogenes
M protein
Important role in pathogenesis of rheumatic fever
M protein
Antigen with no relation to virulence
T substance
Obtained by proteolytic digestion which rapidly destorys M protein
T substance
Little serologic specificity and makes up most of the streptococcal cell body
P substance
Removal of pus and necrotic tissue
Streptodornase
Produced by many strains of Group A b-hemolytic streptococi
Streptokinase
Associated with streptococcal toxic shock syndrome and scarlet fever
Pyrogenic Exotoxins
Molecular weight of Streptolysin O
60,000
Portal of entry of Erysipelas
Skin
Acute, rapidly spreading infection of the skin and subcutaneous
Cellulitis
Flesh eating bacteria
Necrotizing fasciitis
Infection of traumatic or surgical wounds
Bacteremia or sepsis
Spreads by continuity and is highly communicable especially in hot humid climates
Streptococcal pyoderma
Follows a latent period of 1-4 weeks following S. pyogenes infection
Poststreptococcal disease
Develop 3 weeks after pyoderma or impetigo
Acute glomerulonephritis
Most serious sequela of S. pyogenes leading to damage to heart muscle and valves
Rheumatic fever
Culture of S. pyogenes
Throat swab, pus or blood
Antibody determination of S. pyogenes
Serum
Sensitivity of rapid detection of streptococcal antigen from throat swab
60-90%
Serologic test of respiratory disease which is the most widely used
Antistreptolysin
Treatment of S. pyogenes
Penicillin G
Treatment if allergic to Penicillin
Erythromycin
Most dangerous source for spread of S. pyogenes
Nasal discharges
Produce zones of hemolysis that are only slightly larger than the colonies
S. agalactiae
Part of normal vaginal flora in 5-25% women
S. agalactiae
May cause endocarditis in the heart and bacteremia in patients with colonic carcinoma
S. bovis
Classified as viridans streptococci
S. bovis
rarely found in human disease states
Group N streptococci
Skin infection of dogs
S. canis Group G
Dome shape and central plateau with an elevated rim
S. pneumoniae
Most common enterococci
Enterococcus faecalis
Most frequent cause of nosocomial infection
Enterococcus facium