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61 Cards in this Set
- Front
- Back
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Gram positive
Pleomorphic cocci Grows in chains Facultative anaerobes Prefer the presence of CO2 Catalase negative |
Streptococcus
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Serological properties
Lancefield groups, 1933 Hemolytic reactions Biochemical reactions |
Streptococcus
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Streptococcal diseases (6)
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Pneumonia
Strep throat Dental caries Neonatal infections Endocarditis Soft tissue infections |
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S. pyogenes characteristics (7)
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Group A strep
Beta hemolytic M protein F protein G protein Capsule Bacitracin sensitive |
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Diseases of group A strep (3)
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Suppurative diseases
systemic toxemia non-suppurative diseases |
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Suppurative diseases (4)
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Pharyngitis
Cellulitis Fasciitis Puerperal fever |
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Systemic toxemia (2)
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Scarlet fever
Streptococcal toxic shock |
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Non-suppurative diseases (2)
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Rheumatic fever
Glomerulonephritis |
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Group A virulence factors (12)
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Capsule – non-immunogenic
M protein – antiphagocytic F protein – binds epithelial cells G protein - binds antibody molecules Erythrogenic toxin - superantigen Pyogenic exotoxin A - streptococcal TSS Exotoxin B protease - flesh-eating bacteria Streptolysins O and S Streptokinase - plasminogen activator C5a peptidase Hyaluronidase DNase |
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induces chronic inflammation
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Peptidoglycan
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antigenic, cross-reactive with host components
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C-polysaccharide:
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binds antibodies via Fc region
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M-like proteins:
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binds fibronectin
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Protein F:
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resists phagocytosis mimics host antigens
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M protein
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adherence factor
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LTA
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Resists opsonophagocytosis
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Hyaluronic acid capsule:
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Respiratory infections – droplets
Asymptomatic carrier rate __% Patients usually ____yo |
group A infections, 5, 5-15
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Skin infections – contamination of abrasion
Direct contact or shared fomites Patients usually ____ yo or older adults |
group A infections 2-5
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Organisms inhaled and binds to epithelium via F protein
Produces M protein Inhibits phagocytosis and complement Streptolysin damages epithelial tissue Colonization occurs |
group A respiratory infections
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group A scarlet fever clinical presentation (5)
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Extension of strep throat
Infecting strains has a lysogenic phage encoding a pyrogenic exotoxin Exotoxin is spread through circulatory system Diffuse rash over the body and fever Strawberry tongue |
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group A strep throat clinical presentation (2)
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Pharyngitis develops 2 to 4 days after exposure
Sore throat, fever, malaise, headache |
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Infection of the skin and subcutaneous tissues
Requires immediate antibiotic therapy |
Erysipelas
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Systemic toxins
Shock, rash, respiratory and renal failure |
Toxic shock
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Localized skin infection
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Impetigo
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group A skin infections (3)
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Erysipelas, Toxic shock, Impetigo
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Non-suppurative diseases (2)
Post-streptococcal sequelae |
Acute glomerulonephritis
Rheumatic fever |
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Inflammatory response to streptococcal antigens
Fever, carditis, polyarthritis Patients 5-15, approximately 3 weeks after pharyngitis Can last 2-3 months No diagnostic test Chronic, progressive heart damage Prophylaxis prevents reoccurrence |
Rheumatic fever
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Involves deposition of antigen-antibody complexes
Edema, hypertension, proteinuria, hematuria Occurs 10 days following infection |
Acute glomerulonephritis
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Diagnosis of group A streptococcus (3)
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Isolation of the organism
Bacitracin sensitive Rapid strep test Serologic tests Anti-streptolysin O titers |
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Treatment of group A streptococcus
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Penicillin
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Group B strep
Beta hemolytic Capsule Antibody against capsule is protective |
streptococcus agalactiae
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group B diseases (3)
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Neonatal infections
Puerperal sepsis Osteomyelitis |
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group B adult infection predisposing factors (3)
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Diabetes
Cancer Alcoholism |
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group B virulence factors (5)
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DNase
Hyaluronidase Neuraminidase Proteases Hemolysins |
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Capsule inhibits complement
No type-specific antibody in neonates Growth occurs |
Group B streptococcus
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Group B colonize _____ of women
Transient carriage in ______% |
GI and UT, 10-30
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Group B Infection of infant at delivery
____% of infected mothers yield infected infants ______% mortality of infected infants |
1-2, 30-60
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Group B clinical presentation reisk factors (3)
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Risk factors include no maternal antibodies, premature delivery, prolonged membrane rupture
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_______ fever occurs with group B clinical presentation
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Intrapartum
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group B neonate infection (2)
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group B nEarly onset, first few days
Pneumonia, 80%; meningitis, 20-30% Late onset, 3-8 weeks after birth > 90% meningitis eonate infection |
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Group B streptococcus diagnosis (3)
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Isolation of organism
-CAMP test Latex bead agglutination |
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Group B streptococcus treatment
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penicillin and an aminoglycoside
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Group B streptococcus prevention
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screening of pregnant women
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Gram positive diplococcus
Fastidious Alpha hemolytic Encapsulated Not type-able Optichin sensitive |
streptococcus pneumoniae
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streptococcus pneumoniae virulence factors (4)
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Pneumolysin
-Lysis epithelial cells -Inhibits oxidative burst IgA protease Neuraminidase -Capsule Anti-phagocytic |
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5-75% carriage rate
Seasonal variation Mortality Pre-antibiotic 20-30% Currently 5-10% |
streptococcus pneumoniae
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streptococcus pneumoniae diseases (4)
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Pneumonia
Bacteremia Otitis media Meningitis |
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Inhalation of organisms
Capsule inhibits phagocytosis Pneumolysin lyses pulmonary endothelial cells Allows spread into bloodstream Allows growth in alveoli Influx of inflammatory factors Inhibition of lung function |
streptococcus pneumoniae respiratory infection
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streptococcus pneumoniae clinical presentation (4)
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Chills
High fever Rusty sputum Rapid onset |
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streptococcus pneumoniae identification (4)
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Isolation of organism
-Optichin sensitivity Sputum smear Chest X-ray |
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streptococcus pneumoniae treatment
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penicillin
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streptococcus pneumoniae prevention
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vaccine (23 capsular types, 94% of all infections)
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May display all types of hemolysis
20-30% of non-specific pharyngitis |
Group C streptococci
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Non-hemolytic
Ferment esculin |
Group D streptococci
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Part of the old group D strep
Gram positive cocci Catalase negative May produce pseudocatalase Non-hemolytic Grow in 6.5% sodium chloride Hydrolyze esculin Tolerate 40% bile salts Antibiotic resistant |
Enterococcus
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Has No virulence factors
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Enterococcus
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Enterococcus pathogenic species (2)
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E. faecalis
E. faecium |
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Enterococcus diseases (3)
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UTI
Implants Soft Tissue infections |
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Contaminants
Opportunists Nosocomial infections 10% of infections |
Enterococcus
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Persistence of ______________ in toothbrushes and removable orthodontic appliances following treatment of pharyngotonsillitis. Archives of
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group A beta-hemolytic streptococci
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Fluoride exposure attenuates expression of ___________ virulence factors
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Streptococcus pyogenes
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