Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
53 Cards in this Set
- Front
- Back
Staphylococcus Species
|
1. S. aureus 2. S. epidermidis 3. S. saprophytics
|
|
Shared Staphylococcal Properties
|
1. Gram-positive cocci in grape-like cluster 2. Catalase positive 3. Grow in 7.5% salt
|
|
S. aureus Characteristics
|
1. Large beta-hemolytic mucoid colonies 2. Coagulase positive
|
|
S. aureus Virulence Factors
|
1. Surface Components 2. Enzymes 3. Toxins
|
|
S. aureus Virulence Factors: Surface Components
|
1. Capsule 2. Protein A 3. Lipotechoic and techoic acids
|
|
S. aureus Virulence Factors: Enzymes
|
1. Catalase 2. Coagulase 3. Degradative enzymes 4. Penicillinase (Beta-lactamase)
|
|
S. aureus Virulence Factors: Toxins
|
1. Leukocidins 2. Enterotoxins (A-E) 3. Exfoliateive toxins (A,B) 4. Toxic Shock Syndrome Superantigen (TSST-1)
|
|
Catalase
|
Reduces phagocytic killing by converting H2O2 to H2O
|
|
Coagulase
|
Helps encase infection by forming fibrin layer around abscess
|
|
Enterotoxins (A-E)
|
1. Act as superantigens 2. Responsible for gastrointestinal food poisoning
|
|
Exfoliative Toxins (A,B)
|
1. Cause splitting of cell junctions (desmosomes) in epidermis 2. Responsible for scalded skin syndrome
|
|
TSST-1
|
1. Acts as superantigen 2. Promotes massive cytokine release 3. Causes Toxic Shock Syndrome (TSS)
|
|
Diseases Caused by S. aureus
|
1. Toxin-mediated diseases 2. Suppurative Infections
|
|
Diseases Caused by S. aureus: Toxin Mediated
|
1. Food poisoning 2. Toxic Shock Syndrome (TSS) 3. Scalded Skin Syndrome
|
|
Diseases Caused by S. aureus: Toxin Mediated-Food Poisoning
|
1. Due to preformed enterotoxin 2. Quick acting (staph specific)
|
|
Diseases Caused by S. aureus: Toxin Mediated-TSS
|
1. TSST-1 (superantigen) 2. Associated with tampons 3. Multisystem organ involvement 4. Rash 5. Fever and hypotension
|
|
Diseases Caused by S. aureus: Scalded Skin Syndrome
|
1. Exfoliative toxins (A, B) 2. Young children 3. Blister-like lesions all over body 4. Large areas of desquamated epithelium, but no scarring
|
|
Coagulase-Negative Staphylococcal Species
|
1. S. epidermidis 2. S. saprophyticus
|
|
S. epidermidis Clinical Manifestation
|
1. Adheres to artificial heart valves, vascular catheters, shunts, and prosthetic joints. 2. Colonizes implant area
|
|
S. saprophyticus Clinical Manifestation
|
Common urinary tract infection (UTI) in sexually active women - dysuria, pyuria and bacteruria
|
|
Streptococcal Pathogenic Species
|
1. S. pyogenes 2. S. agalactiae 3. Viridans group 4. S. pneumoniae
|
|
Shared Streptococcal Properties
|
1. Gram-positive spherical or football-shaped cocci in pairs or chains 2. Catalase negative
|
|
Alpha Hemolysis
|
1. Incomplete hemolysis (greenish zone around colony) 2. S. pneumoniae and Viridans streptococci
|
|
Beta Hemolysis
|
1. Complete hemolysis (clear zone around colony) 2. S. pyogenes and S. agalactiae
|
|
Gamma Hemolysis
|
1. No hemolysis 2. Enterococcus spp. (some)
|
|
S. pneumonia vs. Viridans: Distinguishing Property
|
1. S. pneumonia: optochin sensitive 2. Viridans: optochin resistant
|
|
S. pyogenes vs. S. agalactiae: Distinguishing Property
|
1. S. pyogenes: Bacitracin sensitive 2. S. agalactiae: Bacitracin resistant
|
|
Group A Streptococcal spp.
|
S. pyogenes. 1. Beta-hemolytic 2. Sensitive to bacitracin (A disk)
|
|
Group A Streptococci: Virulence Factors
|
1. Surface Components 2. Enzymes 3. Toxins
|
|
Group A Streptococci: Virulence Factors-Enzymes
|
1. Hyaluronidase 2. Streptokinase 3. Streptolysin O and S
|
|
Streptokinase
|
Promotes bacterial spread into tissue by breakind down blood clots
|
|
Streptolysin O & S
|
Lyse blood cells and platelets; stimulates release of lysosomal enzymes
|
|
Group A Streptococci: Virulence Factors-Toxins
|
Pyrogenic/erythrogenic exotoxins (some act as superantigens)
|
|
Group A Streptococci: Diseases
|
1. Localized suppurative 2. Toxin-mediated 3. Nonsuppurative autoimmune sequelae
|
|
Group A Streptococci: Diseases-Localized Suppurative
|
1. Erysipelas 2. Impetigo 3. Pharyngitis (Strep throat) 4. Scarlet Fever 5. Necrotizing fasciitis
|
|
Group A Streptococci: Diseases-Toxin Mediated
|
1. Streptococcal TSS 2. Scarlet fever
|
|
Streptococcal TSS
|
1. Cellulitis 2. Shock 3. Multisystem organ failure 4. Generalized skin flushing 5. (Adult male)
|
|
Scarlet Fever
|
1. Child 2. Strawberry tongue 3. Diffuse sandpaper-like erythematous rash over body within 24 to 48 hours after pharyngitis onset 4. Rash fades in 5 to 7 days with desquamation
|
|
Group A Streptococci: Diseases-Autoimmune Sequelae
|
1. Acute glomerulonephritis 2. Rheumatic Fever
|
|
Acute Glomerulonephritis
|
1. Child or teenager 2. Hematuria 3. Red blood cell casts 4. Proteinuria 5. Hypertension 6. Periorbital edema 7. History of recently treated skin infection
|
|
Rheumatic Fever
|
Cross-reaction of antibodies, with antigens against the heart -> pancarditis
|
|
Group B Streptococcal Species
|
S. agalactiae
|
|
Group B Streptococci: Identification
|
1. Beta-hemolytic 2. Resistant to bacitracin 3. Positive CAMP test
|
|
Group B Streptococci: Diseases
|
Neonatal meningitis
|
|
Viridans Streptococcal: Habitat
|
Major part of normal flora of mouth and teeth
|
|
Viridans Streptococcal: Identification
|
1. Alpha hemolytic 2. Resistant to Optochin
|
|
Viridans Streptococcal: Diseases
|
1. Streptococcal endocarditis 2. Dental caries
|
|
Streptococcus Pneumoniae (Pneumococcus): Identification
|
1. Alpha hemolytic 2. Sensitive to Optochin (P disk)
|
|
Streptococcus Pneumoniae (Pneumococcus): Pathogenesis
|
1. Aspiration of nasopharyngeal secretions into lower airways leads to rapid growth of pneumococci in alveolar spaces 2. Promoted by reduced clearance of airways due to disruption of ciliated epithelium in upper respiratory tract by viral infections or smoking
|
|
Streptococcus Pneumoniae (Pneumococcus): Diseases
|
Meningitis
Otitis media Pneumonia Sinusitis |
|
Enterococcal Species
|
1. E. faecalis 2. E. faecium
|
|
Enterococcus: Identification
|
1. Gram-positive cocci in twisted chains
|
|
Enterococcus: Virulence Factors
|
Inherently resistant to many antibiotics
|