MIDTERM 01 - Gram-Positive Cocci Flashcards
Gram-positive spherical cells arranged in grapelike irregular clusters
Staphylococci
Staphylococci produces __________, which converts H2O2 to H2O and O2
Catalase
2 Staphylococcus aureus enzymes (CC)
Coagulase, Clumping factor
Clots oxalated or citrated plasma (Staphylococcus aureus enzymes)
Coagulase
Adheres organism to fibrinogen and fibrin (Staphylococcus aureus enzymes)
Clumping factor
Lyse many cells and creates pores that cause release of inflammatory mediators (Staphylococcus aureus toxins)
Hemolysins
Is a superantigen; produces the generalized desquamation of staphylococcal scaled skin syndrome (Staphylococcus aureus toxins)
Exfoliative toxins
Is a superantigen that binds to MHC-II molecules which promotes the manifestations of toxic shock syndrome (Staphylococcus aureus toxins)
Toxic shock syndrome toxin-1 (TSST-1)
Is heat stable, resistant to gut enzymes, and causes food poisoning (Staphylococcus aureus toxins)
Enterotoxins
Characterized by a localized abscess (Staphylococcus aureus clinical findings)
Furuncle/Carbuncle
Characterized by a local infection of superficial layers of skin, especially in children (Staphylococcus aureus clinical findings)
Impetigo/Pyoderma
Characterized by a supparation (abscess) that occurs in other parts causing endocarditis, osteomyelitis, meningitis, and pneumonia (Staphylococcus aureus clinical findings)
Bacteremia
Supparation in blood vessels of the metaphysis of a long bone
Osteomyelitis
Its incubation period is 1-8 hours; characterized by symptoms that include N/V, diarrhea, and fever (Staphylococcus aureus clinical findings)
Food poisoning
Characterized by an abrupt onset of high fever, vomiting, diarrhea, myalgia, scarlatiniform rash, and hypotension with cardiac and renal failure in most severe cases (Staphylococcus aureus clinical findings)
Toxic shock syndrome
Characterized by redness and tenderness of the central face, neck, trunk, and intertriginous zones (Staphylococcus aureus clinical findings)
Scalded skin syndrome
Enzyme that hydrolyzes β-lactam antibiotics; give β-lactamase resistant penicillins
β-lactamase
Gene that gives resistance to β-lactamase resistant penicillins due to low affinity PBPs; give vancomycin
mecA gene
Bacteria that causes 75% of coagulase-negative staphylococcal infections (Streptococcus species)
Streptococcus epidermidis
Bacteria that is part of the normal flora of the skin, respiratory tract, and GIT; relatively common cause of UTIs in young women (Streptococcus species)
Streptococcus saprophyticus
Gram-positive spherical cells arranged in pairs or chains
Streptococci
Grouping based on Lancefield antigens (carbohydrates) present in the cell wall
Lancefield grouping
N-acetylglucosamine (Lancefield group)
Group A
Rhamnose-glucosamine (Lancefield group)
Group B
Rhamnose-N-acetylgalactosamine (Lancefield group)
Group C
Glycerol teichoic acid containing D-alanine and glucose (Lancefield group)
Group D
Glucopyranosyl-N-acetylgalactosamine (Lancefield group)
Group F
Also known as pneumococci; normal flora of the upper respiratory tract of 5-40% of humans (Streptococcus species)
Streptococcus pneumoniae
Pneumonia of sudden onset; symptoms include fever, chills, sharp pleural pain, and bloody or rusty colored sputum (Clinical findings of Streptococcus pneumoniae)
Community-acquired pneumonia
Treatment for Streptococcus pneumoniae
Parenteral β-lactams
2 vaccines used for prevention of Streptococcus pneumoniae
PPSV23, PCV13
The most prevalent members of the normal microbiota of the upper respiratory tract (Examples of gram-positive cocci)
Viridans streptococci
Condition that is due to large polysaccharides synthesized by Streptococcus mutans (Clinical findings of Viridans streptococci)
Dental caries
Condition that involves the rapid destruction of the valves; leads to fatal cardiac failure in days-weeks unless surgery is performed (Clinical findings of Viridans streptococci)
Acute endocarditis
Condition that is slowly progressive and often involves abnormal valves (Clinical findings of Viridans streptococci)
Subacute endocarditis
Major virulence factor of Streptococcus pyogenes
M protein
Enzyme that transforms plasminogen into plasmin, which digests fibrin, allowing bacteria to escape from blood clots (Streptococcus pyogenes enzymes)
Streptokinase (Fibrinolysin)
Enzyme that degrades DNA and liquefies pus, allowing the bacteria to spread (Streptococcus pyogenes enzymes)
Deoxyribonuclease (DNAse)
Enzyme that hydrolyzes hyaluronic acid, a component of ground substance in ECM of CT and aids in spreading (Streptococcus pyogenes enzymes)
Hyaluronidase
Is a superantigen that is associated with streptococcal toxic shock syndrome and scarlet fever (Streptococcus pyogenes toxins)
Pyrogenic exotoxins (Erythrogenic toxins)
Hemolysin that induces antistreptolysin O (ASO) production (Streptococcus pyogenes toxins)
Streptolysin O
Hemolysin responsible for β-hemolysis on BAP; not antigenic (Streptococcus pyogenes toxins)
Streptolysin S
Its portal of entry is the skin; presents raised, red lesions, a brawny edema, and a rapidly advancing, sharply demarcated margin (Clinical findings of Streptococcus pyogenes)
Erysipelas
Its portal of entry is parenteral; is an acute, rapidly spreading infection of the skin and subcutaneous tissues (Clinical findings of Streptococcus pyogenes)
Cellulitis
Its portal of entry is parenteral; it is a “flesh eating disease” that is extensive and involves a very rapidly spreading necrosis of the skin, tissues, and fascia (Clinical findings of Streptococcus pyogenes)
Necrotizing fasciitis (Streptococcal gangrene)
Its portal of entry is the uterus; it is a septicemia originating in the infected wound after delivery (Clinical findings of Streptococcus pyogenes)
Puerperal fever
Its portal of entry is parenteral; it can be rapidly fatal (Clinical findings of Streptococcus pyogenes)
Bacteremia/Sepsis
It is the most common infection caused by Streptococcus pyogenes; it involves adherence to pharyngeal epithelium via lipoteichoic acid binding to fibronectin (Clinical findings of Streptococcus pyogenes)
Streptococcal pharyngitis
It leads to shock, bacteremia, respiratory failure, and multiorgan failure; tends to occur after minor trauma in otherwise healthy persons with several presentations of soft tissue infection (Clinical findings of Streptococcus pyogenes)
Streptococcal toxic shock syndrome
It associated with pharyngitis or with skin or soft tissue infection; its symptoms include a strawberry tongue and bright red, sandpaper rash (Clinical findings of Streptococcus pyogenes)
Scarlet fever
Are autoimmune disorders which appears after an acute S. pyogenes infection
Poststreptococcal diseases
A poststreptococcal disease more commonly preceded by a Streptococcus pyogenes skin infection or pharyngitis (Poststreptococcal diseases)
Poststreptococcal glomerulonephritis
A poststreptococcal disease more commonly preceded by pharyngitis (Poststreptococcal diseases)
Rheumatic fever
Most serious sequela of S. pyogenes; mainly a disease of children 5-14 years old (Poststreptococcal diseases)
Rheumatic fever
Treatment for Streptococcus pyogenes
Penicillin G
Part of the normal vaginal flora and lower GIT in 5-30% of women (Streptococcus species)
Streptococcus agalactiae
Involves an infection during the 1st month; may present as fulminant sepsis, meningitis, or respiratory distress syndrome (Clinical findings of Streptococcus agalactiae)
Neonatal sepsis
Prevention for Streptococcus agalactiae
IV ampicillin
Previously classified as group D streptococci; are commensal bacteria of the normal enteric microbiota
Enterococci
2 most common causes of enterococci infection (EE)
Enterococcus faecalis, Enterococcus faecium
Are critical, multidrug-resistant bacteria which are the leading cause of HAIs
ESKAPE pathogens
6 ESKAPE pathogens
Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter sp
German word for swelling
Quellung
Reaction where antibodies bind to bacterial capsule to make it more opaque; diagnosis for Streptococcus pneumoniae
Quellung reaction
