Micro G+ Quiz 2 Flashcards
Staphylococcus metabolism
Facultative anaerobe
Staphylococcus catalase test
positive
Staphylococcus optimal temperature
30º C (18º-40ºC)
Staphylococcus environmentally resists:
Drying, Salt (Mannitol Salt Agar used)
Staphylococcus aureus virulence factors
Peptidoglycan Teichoic acids – (ID species/strain) Protein A Coagulase Slime Layer Capsule (stop phagocytosis)
Staphylococcus aureus toxins
Alpha – cell lysis, tissue damage Beta – cell lysis, tissue destruction Gamma – rbc lysis Delta – detergent on rbc’s PV – leukocidin Exfoliative toxins (ETA and ETB) Enterotoxins Superantigens (A, B, etc.) – stimulate T-cells non-specifically Catalase-H2O2 breakdown (ALL Staphylococcus!!) Hyaluronidase -spreading in CT Staphylokinase -(fibrinolysin) dissolves clots Penicillinase
Diseases caused by Staphylococcus aureus
SOFT PAINS
SKIN (colonization)- folliculitis (hair follicule), furuncle/carbuncle (sebaceous gland), impetigo (superficial, children).
(exo/entero)TOXINS -food poisoning, scalded skin (exfoliative toxin), toxic shock (superantigen).
INTERNAL -bacteremia, endocarditis, osteomyelitis, pneumonia
Staphylococcus aureus hemolysis test
beta
clear
Staphylococcus epidermidis hemolysis test
Gamma or alpha (none or incomplete)
Staphylococcus aureus coagulase test
positive!!
Staphylococcus lugdunensis coagulase test
negative
Staphylococcus saprophyticus coagulase test
negative
Staphylococcus hemolyticus coagulase test
negative
Streptococcus coagulase test
negative
Two most important coagulase negative staphylococcus species
Staphylococcus epidermidis & Staphylococcus lugdunensis
What diseases do Staphylococcus epidermidis & Staphylococcus lugdunensis cause
Infections of catheters, prosthetic valves & joints
Diseases caused by Staphylococcus epidermidis
Bacteremia, endocarditis, surgical wound infections, UTI
Diseases caused by Staphylococcus lugdunensis
Arthritis, bacteremia, endocarditis, UTI
Diseases caused by Staphylococcus saprophyticus
UTI and other opportunistic infections
Diseases caused by Staphylococcus hemolyticus
Bacteremia, bone/joint, endocarditis, UTI, wound infection
Streptococcus metabolism
Facultative anaerobe
Streptococcus environmentally resists:
Some drying, salt
Streptococcus pyogenes Serological Grouping
GAS
Streptococcus agalactiae Serological Grouping
GBS
Streptococcus bovis Serological Grouping
GDS (enterococcus)
Streptococcus pneumoniae Serological Grouping
None
Streptococcus mutans Serological Grouping
None, viridans group
Streptococcus mitas Serological Grouping
None, viridans group
Streptococcus salivarius Serological Grouping
None, viridans group
Streptococcus pyogenes virulence factors
1) Capsule
2) Adhesins
- Lipoteichoic acid
- M-protein family
- F-protein – binds epithelial cells
Streptococcus pneumoniae virulence factors
HUGE capsule (resist phagocytosis)
IgA proteases
pnuemolysin to destroy ciliated cells
Streptococcus mutans virulence factors/metabolism
Acidogenic/acidouric
Streptococcus pyogenes toxins
Pyrogenic exotoxins - mitogens for T-cells/inflamm/rash/fever pus –SpeA, SpeB, SpeC
passed between bacteria by phage conversion
Streptolysin S – lyse wbc’s, platelets, rbc’s
Streptolysin O – lyses wbc’s, platelets, rbc’s (ASO test = recent strep infection)
Streptokinase – lyse blood clots allows spread
Hyaluronidase – spreading
DNase/streptodornase
C5a peptidase
Name the 2 post-Streptococcal infection Diseases
- Rheumatic fever: 2 week post effect (cross-reactive antibody, ASO test) age 5-15, aschoff body —> dental prophylaxis to prevent endocarditis
- Post-streptococcal glomerulonephritis (from antibodies to streptococcus clogging kidneys, ASO test)
Suppurative Streptococcus pyogenes Diseases
- *Necrotizing fasciitis: SUPERANTIGENS deeper infection (fascia)
- *Pyoderma/impetigo: purulent skin infection – hot climates, young kids
- *Erysipelas: acute skin infection – larger area
- *Cellulitis: deeper skin infection
- *Toxic Shock syndrome: superantigens – usually bacteremic/systemic
- *Endocarditis: infection of a heart valve
- *pharyngitis
Other disease caused by Streptococcus pyogenes
Scarlet fever: rash/skin peeling
Disease caused by Streptococcus agalactiae
S. agalactiae is GBS – most serious disease of neonate, cause septicemia/meniningitis/
-bacteremia in newborns (screen moms, 10-30% women carry, 60% babies get sick)
Disease caused by Streptococcus bovis
S. bovis = mystery:
15% of colon cancer patients have
Disease caused by Streptococcus pneumoniae
Lung infection, spread to sinuses & meninges, increase C-reactive protein
Disease caused by Streptococcus mutans
Dental caries
Treatment for Streptococcus pneumoniae infections
- Becoming penicillin resistant —> vancomycin
2. polysaccharide multi-strain vaccine given to under 2 yr & 65+
To prevent secondary Streptococcus pyogenes infections
Penicillin, cephalosporin, within 10 days
Diagnosis of Streptococcus pyogenes infection
- Elevated CRP
2. Cells lyse rapidly with bile
Streptococcus pyogenes hemolysis test
beta
Streptococcus agalactiae hemolysis test
beta