Module 9 Flashcards
What do S. aureus and S. pyogenes have in common?
a - they both produce coagulase
b - they both secrete catalase
c - they are both Gram + cocci
d - they are both ‘lactic acid bacteria’ (pyruvate –> lactate)
e - all of these are shared properties
c - they are both Gram + cocci
what is a gram + cocci that grows in pairs and chains using “fermentation”
streptococcus bacteria
all streptococci are Gram + ___ that tolerate ___ oxygen and acid
fermenters, low
T/F many streptococci are normal flora, oral and intestinal, on moist skin , and used to make fermented foods
true
what components of streptococci are used to evade phagocytosis
capsules & M proteins
what do S. pyogenes (G.A.S) cause
- strep throat
- rheumatic heart disease
- necrotizing fasciitis
what do S. pneumonia cause
- upper respiratory
- most common meningitis
‘mitis’
what do S. mutans & S. sobrinus cause
- dental caries
- periodontal disease
what does pyogenic mean
pus forming
what bacteria is in the pygoenic group
s. pyogenes
what bacteria are in the viridans
s. pneumonia, s. mutans, & s. sobrinus
group a strep is what kind of hemolytic
beta
s. pneumoniae & s. mutans are what kind of hemolytic
alpha
what strep group is the bacteria that dentist worry about releasing during dental procedures because it can cause endocarditis
s. oralis
how do s. pyogenes exchange DNA and how does this effect the mutation rates
- transformation
- increases during adaptation to host tissues
what are the diseases that s. pyogenes can cause
- PHARYNGITIS
- septicemias
- impetigo
- NECROTIZING FASCIITIS
- SCARLET FEVER
- pneumonia
- RHEUMATIC FEVER
- glomerulonephritis
what is an autoimmune disease that causes damage to the heart valve tissues
rheumatic fever
what is the disease that involves immune complexes depositing in the kidney causing transient inflammation
glomerulonephritis
what are the skin and soft tissue infections of S. pyogenes
- impetigo / cellulitis
- erysipelas
- necrotizing fasciitis
- streptococcal toxic shock syndrome
what are the respiratory infections of S. pyogenes
- pharyngitis
- scarlet fever
- pneumonia
what is scarlet fever
a childs reaction to secreted toxins in the blood
how does S. pyogenes pneumonia occur
- preceded by viral infection
- travels to lungs from URT
- rapidly fatal even with appropriate antibiotic therapy
what is an acute-onset illness characterized by fever, hypotension, sunburn-like rash, and end-organ damage
toxic shock syndrome
what are the clinical features of toxic shock syndrome
- fever
- chills
- headache
- nausea
- vomiting
progress to
- sepsis w/ hypotension
- tachycardia
- tachypnea
- specific organ failure
what is toxic shock syndrome caused by
bacteria entering the blood stream and secreting super-antigen proteins that are able to lock T-cells onto antigen presenting cells
what are the virulence factors of S. pyogenes
- cell wall
- M protein
- conventional capsule
- endotoxins
what are the M proteins
long fibrillar molecules that extend out from the surface of the cell and create a protein capsule
what is the function of the M proteins
inhibits complement fixation and opsonization and thus inhibits phagocytosis
what is the conventional capsule of s. pyogenes
polysaccharide polymer that is anti-phagocytic
what are the 2 endotoxin virulence factors of s. pyogenes
- cytolytic toxins
- pyrogenic exotoxins
what exotoxin causes beta-lysis on blood agar
cytolytic toxin = “streptolysin”
what is the exotoxin super-antigen that causes scarlet fever
pyrogenic exotoxin
what does pyrogenic mean
fever-producing
what do pyrogenic exotoxins do
- rash & fever of scarlet fever
- cause toxic shock
- stimulates cytokine production in macrophages causing inflammation
what are pyrogenic exotoxins produced by
only by strains lysogenized with specific phages
what does protein G do
binds to Fc of immunoglobulin and interferes with opsonization and ultimately blocks phagocytosis
how is s. pyogenes transmitted
- respiratory droplets
- exchanging secretions via close physical contact
- direct skin contact
what is the treatment for s. pyogenes
topical antibiotics - penicillins & cephalosporins
T/F there is a vaccine for S. pyogenes, but not for s. pneumoniae
false - there are NO vaccines for S. pyogenes, only for S. pneumoniae
how do you adjust the treatment if there is a more invasive disease or STSS
increase penicillin G dose & may add clindamycin
*****what is the difference between greek and roman/latin letter (A, B, etc.) designations for groups of streptococci?
a - greek indicated different species in the genus
b - roman indicate different serotypes
c - greek indicate different hemolysis patterns
d - b&c
d - b&c
what are the important post-infection sequelae in streptococcus pyogenes (G.A.S.) disease?
a - scarlet fever
b - rheumatic fever
c - glomerulonephritis
d - b&c
e - all of these
d - b&c
what are the secreted damaging enzymes causing hemolysis on blood agar generically called?
a - streptolysins
b - Spe proteins
c - pyrogenic toxins
d - G proteins
a - streptolysins
