Gram (+) cocci - Sketchy Copy Flashcards
Staph, Strep, and Enterococcus
Staphylococcus aureus
lab tests
The golden staff of moses
gram (+) cocci
ß hemolytic
Ferments Mannitol Salt Agar (turns yellow)
catalase (+)
coagulase (+)
Staphylococcus aureus
Biochemical Properties
The golden staff of moses
Catalase - 2H2O2 to 2H2O + O2
Cougulase - Fibrinogen to Fibrin
Hyaluronidase, Staphylokinase, Lipase, Nuclease
Staphylococcus aureus
Cytotoxins
The golden staff of moses
Hemolysin - Destruction of RBC and Some WBCs
Panton Valentine Leukocidin (PVL) - Destruction of WBCs
Staphylococcus aureus
Protein A
Exofoliative Toxin
Enterotoxin
The golden staff of moses
Protein A: component of cell wall that binds to FC region of antibodies - Evading Phagocytosis
Exofoliative Superantigen A-B - Intercellular adhesion of Keratinocytes leading to Scalded Skin Syndrom
Enterotoxin Superantigen A-R - Gastroenteritis, Vomiting and Diarrhea
Staphylococcus aureus
signs and symptoms
The golden staff of moses
Pneumonia -patchy infiltrate on x-ray
Septic arthritis
Large erythematous abcesses, Imptego
Tricuspid valve endocaritis -IV drug users
Scalded skin syndrom
Toxic shock syndrome
Staphylococcus aureus
Toxis Shock Syndrome (TSS) MOA
The golden staff of moses
Toxic Shock Syndrome (TSS) by -TSST superantigen
- commonly caused by leaving in a bandage or tampon
- causes nonspecific binding of MHC II to T cell receptors causing over reaction and cytokine storm
Staphylococcus aureus
Food poisoning MOA
The golden staff of moses
-due to preformed toxins
(not the actual organisms)
-usually from meats and mayonnaise
(also salad and creme filled pastries)
-usually sick in 6 hours
Staphylococcus aureus
Treatment
The golden staff of moses
For MARSA:
Vancomycin
For methicillin sensitive S. aureus use:
Nafcillin
(“Naf for staph”)
Staphylococcus epidermidis
lab tests
Beauty and the Plumber
gram (+) cocci
catalase (+)
coagulase (-)
urease (+)
S. epidermidis = Novobiocin sensitive
Staphylococcus saprophyticus
Treatment
Beauty and the Plumber
Ciprofloxacin (Fluroquinalone)
Staphylococcus saprophyticus
lab tests
Beauty and the Plumber
gram (+) cocci
S. Saprophyticus = Novobiocin resistance
catalase (+)
coagulase (-)
urease (+)
Staphylococcus epidermidis
signs and symptoms
Beauty and the Plumber
Normal skin flora
Infects hardware, orthopedic joints, catheter tubes, heart implants (endocarditis)
Uses biofilms (polysaccharides)
Staphylococcus saprophyticus
signs and symptoms
Beauty and the Plumber
UTI’s
in
Sexually Active Females
Staphylococcus epidermidis
Treatment
Beauty and the Plumber
Vancomycin
Strep pyogenes (Group A strep)
lab tests
The Pie Genies’ Bakery
gram (+) cocci
catalase (-)
ß hemolytic
Bacitracin sensitive
encapsulated (hyaluronic acid)
Strep pyogenes (Group A strep)
signs and symptoms
The Pie Genies’ Bakery
SpeB - Necrotizing Fascitis
SpeA/C: Pharyngitis, Scarlet fever, Toxic Shock Like Syn, Impetigo
Erysipelas (Red lesion with well demarcated border; S. Pyogenes is the most common cause)
Rheumatic fever
Post Strep Glomerulonephritis
Strep pyogenes (Group A strep)
Scarlett Fever
The Pie Genies’ Bakery
Strawberry tongue
pharyngitis
widespread rash that spares the face
Toxic Shock Like Syndrome (TSLS)
-mediated by super antigen SpeA, SpeC
Necrotizing Fasciitis
-mediated by super antigen SpeB
Strep pyogenes (Group A strep)
Rheumatic Fever
The Pie Genies’ Bakery
VF = M protein
-interferes with opsonization, antiphagocytic
Mimics antibodies in heart causing problems with Mitral Valve.
(molecular mimicry, elicits humoral response)
Pharyngitis precipitates RF (if not treated promptly) but NOT IMPETIGO
JONES symptoms
Strep pyogenes (Group A strep)
Post Strep Glomerulonephritis
The Pie Genies’ Bakery
Type III hypersensitivity reaction
(deposition of antibodies in glomerulus)
Puffy cheeks w/ nephritis
Cola colored urine
Occurs two weeks after strep infection
Can occur after pharyngitis AND impetigo
Strep pyogenes (Group A strep)
Rheumatic Fever J♥NES signs
The Pie Genies’ Bakery
J = Joints
♥ = Heart problems
N = Nodules on extensor surfaces
(often forearms, elbows, knees)
E = Erythema marginatum
(pink rings)a
S =Sydenham’s Chorea
(rapid involuntary movements of hands, feet, face)
Strep pyogenes (Group A strep)
Habitat and Transmission
The Pie Genies’ Bakery
Human Skin, Throat
Direct contact or Respiratory Droplet
Strep pyogenes (Group A strep)
Treatment
The Pie Genies’ Bakery
Penicillin
Strep pyogenes (Group A strep)
VF
The Pie Genies’ Bakery
Scarlet Fever: super antigen SpeA, SpeC**
Necrotizing Fasciitis: SpeB**
Rheumatic Fever: M protein
Other VF:
-Streptolysin O (allows ß hemolysis; we generate ASO antibodies to this)
-Streptokinase (converts plasminogen to plasmin; plasmin is fibrinolytic)
-DNA’ases (depolymerize DNA)
Strep agalactiae (Group B strep)
Habitat
Galactic Baby
Hauman Vagina and GI
Strep agalactiae (Group B strep)
lab tests
Galactic Baby
gram (+) cocci
ß hemolytic (⬆ zone when plated w/ S. aureus)
hippurate (+)
Bacitracin resistant
CAMP test (+) (ddx S. agalactiae from all other strep)
encapsulated (polysaccharide)
Strep agalactiae (Group B strep)
signs and symptoms
Galactic Baby
Major infection in newborns
Most likely to cause meningitis in neonates
Sepsis in neonates
Pneumonia
Strep agalactiae (Group B strep)
Treatment
Galactic Baby
Mother is cultured at 35 weeks
Penicillin given to mother intrapartum to prevent Group B Strep
Strep pneumonia
lab tests
The alpha knight tournament
gram (+) cocci
catalase (-)
α hemolytic (surrounding zone is a green hue)
Optochin Sensitive
Lancet** shaped _diplo_cocci**
Bile soluble (does not grow in bile)
Polysaccharide Capsule (Major VF!)
Strep pneumonia
signs and symptoms
1 cause of MOPS
The alpha knight tournament
Rust collored sputum
lobar pneumonia
(Meningitides, Otitis Media, Pneumonia, Sinusitis)
Strep pneumonia
VF
The alpha knight tournament
Polysaccharide Capsule
Strep pneumonia
MOA
The alpha knight tournament
Protease that cleaves IgA
Allows invasion of mucosa reducing host defenses
Removal of spleen leads to susceptibilty of infection by encapsulated organisms like in sickle cell anemia.
Strep pneumonia
Treatment
The alpha knight tournament
Azithromycin Macrolides
Ceftriaxone
Strep pneumonia
Vaccines
The alpha knight tournament
Adult:
23 valiant polysaccharide
(T-cell independent response creates IgM)
Children:
7 valent conjugated to a protein
(more robust, leads to production of IgG in children)
Strep viridians
lab tests
The alpha knight tournament
gram (+) cocci
catalase (-)
Optochin Resistant
Bile resistant (grows in bile)
NOT encapsulated (ddx from S. Pneumonia)
Strep viridians
MOA
The alpha knight tournament
Synthesizes Dextran’s from glucose
Allows Strep viridians to adhere to any fibrin from platlets that have been damaged in heart.
Strep Sanguineous adheres to fibrin platelet aggregates in damaged heart valves, most common in mitral valve.
Strep viridians
signs and symptoms
The alpha knight tournament
associated with dental carries (cavities!)
Enterococcus
General Properties
Protest at the Caucus
Group D Sterp
Gram+ in Short chains or Pairs
Habitat - Normal Intestinal flora, Urethra and Female Genital tract
Enterococcus
lab tests
Protest at the Caucus
gram (+) cocci
PYR+ and Catalase (-)
6.5% NaCl Resistant - grows in 6.5% NaCl
Bile resistant - grows in bile Esculin Agar - Black
NOT encapsulated (ddx from S. Pneumonia)
Enterococcus
Pathogenesis
Protest at the Caucus
Nosocomial Infection:
1) Easily grown and Resistance developing
2) Bile and Salt resistance
3) Biofilm Formation
Enterococcus
signs and symptoms
Protest at the Caucus
UTI’s
Endocarditis and Sepsis
Infection of biliary tree
Enterococcus
Treatment
Protest at the Caucus
Nosocomial infection resisant to almost every antibiotic we have.
Vancomycin resistant
Linezolid
Tigacycline
