S. pyogenes - Anaerobic cocci Flashcards
What type of hemolysis is seen with S. pyogenes?
beta-hemolytic
Is S. pyogenes catalase positive or negative?
catalase negative
What antibiotic is S. pyogenes susceptible to? Resistant to what?
bacitracin; optochin
S. pyogenes is the only strep that gives a positive reading in this test
PYR
What is the nemonic for diseases caused by s. pyogenes?
Princess Scarlett Impeded Celulitis and Necrotising Toxic Shock by Eating Ripe Garbonzos
How does s. progenies spread?
respiratory droplets - crowded environments
How many deaths are there per year due to GAS (s. pyogenes) infections
0.25 mil
Who is at risk for S. pyogenes?
5-15yr (pharyngitis - strep throat)
2-5 yr (poor hygiene - skin infections)
soft tissue infections and bacteremia - TSS
There is a seasonal aspect to s. pyogenes. Describe the risks in summer and winter.
winter: pharyngitis (strep throat)
summer: pyoderma
Strep throat can be caused by s. pyogenes. What are complications associated?
peritonsilar and retropharyngeal abscess; rheumatic fever and acute glomerulonephritis
This is a disease caused by S. pyognes. It is not too common nowadays. Three toxins spread through the blood and localize in the skin. There is an erythematous sand paper rash on chest and then it spreads to the extremities. There is also a strawberry tongue associated with this disease.
Scarlet Fever
S. pyogenes is the #2 cause of this disease. The disease covers the face to the legs in vesicle–>pustules—>ruptures and crusts over. Patients don’t appear ill. It is more common in the summer and in semi tropical climates. It is often seen in kids with poor hygiene.
Strep Impetigo/Pyoderma
This disease caused by s. pyogenes involves local inflammation, fever, lymph issues and skin and subcutaneous tissues due to trauma/surgery, or a bite - may not see entry site.
Cellulitis
This disease caused by s. pyogenes is similar to cellulitis but less deep. The skin is bright red and there is a malar region of the face and a butterfly rash that starts on one side of the nose and spreads to the other side.
erysipelas
This disease caused by s. pyogenes starts out like cellulitis 60% of the time. It can lead to bullous gangrene and systemic signs. It requires extensive debridement and antibiotic therapy.
Necrotizing Fasciitis
This disease caused by s. pyogenes is a form of bacteremia. It is seen rarely with the s. pyogenes pharyngitis, occasionally with cellulitis, and always in necrotizing fasciitis
Strep TSS
This disease caused by s. pyogenes produces subcutaneous nodules and arthralgia which leads to arthritis. The disease onset is 1-3 wks after infection, usually after pharyngitis. It’s less common in developed nations. The specific GAS of this disease is encapsulated and rich in immunogenic M proteins similar to the heart. Proteins -> cross reactivity -> pancarditis. Prophylactic antibiotics prevent any further attack by GAS (will have anti-SLO and DNaseB)
Acute Rheumatic Fever
This disease caused by s. pyogenes follows pharyngitis and skin infections. Prophylactic antibiotics are not recommended. Ag-Ab complex on glomerular base membrane -> capillaries filled with PMNs and monocytes. Acute inflammation, hypertension, hematuria, proteinuria are also symptoms (will have anti-DNaseB)
acute glomerulonephritis
S. agalactiae (GBS) is gram (__), catalase (__), and its cocci are in long ___
gram +
catalase -
cocci (long chains)
What antibiotic is s. agalactiae resistant to?
bacitracin
What test does s. agalactiae give a positive result for?
CAMP test (synergistic hemolysis)
hint: galactiae looks like the word glacier -> Glacier national park -> camping
What type of hemolysis does s. agalactiae show?
beta hemolysis
Where is s. agalactiae found?
normal flora in gut
What kind of disease does s. agalactiae cause in pregnant women?
UTI, endometritis (after delivery), chorioamniotitis (2nd trimester), and postpartum sepsis
What kind of disease does s. agalactiae cause in men and non-pregnant women?
usually affects the old or IC - bacteremia, pneumonia, bone and skin/soft tissue infections
What kind of disease does s. agalactiae cause in infants?
aspiration of infected amniotic fluid can cause pneumonia/bacteremia/meningitis -> deafness or blindness (early onset: 5% mortality); bacteremia with meningitis ->neurological problems (late onset: high survival rate)
S. pneumoniae is gram (__) and ____ shaped
+ ; lancet
S. pneumoniae is often capsulated. True or false?
true
What type of hemolysis does s. pneumoniae show?
alpha hemolysis
What antibiotic is s. pneumoniae susceptible to? It is also susceptible to ___ salt
optochin (p-disk); bile (not in gut)
Where does s. pneumoniae colonize? How does it spread?
nasopharynx; spreads by rep drops/fomites
Where is s. pneumoniae mostly endogenous?
lungs and blood
S. pneumoniae is the #1 cause of what three diseases?
bacterial sinusitis, otitis media, and meningitis
This disease caused by s. pneumoniae often follows viral infection. A productive cough, pleural pain, dyspnea, tachypnea, tachycardia, sweats, and malaise are associated with this disease. PMNs and lancet shaped diplococci are in rusty sputum (blood leaks from capillaries).
pneumonia
what do s. pneumoniae colonies look like on blood agar plate?
mucoid looking colonies
For each virulence factor of s. pneumoniae, give its function: PspA Hyaluronate lyase Neuraminadase capsule proteases pneumolysin
PspA: anti complement
Hyaluronate lyase: increases tissue permeability
Neuraminadase: bacterial adherence
capsule: most important factor - pathogenisis, vaccine target
Proteases: degrade IgA
Pneumolysin: lyses host cell -> edema -> hemorrhage -> bacterial growth and spread into blood
This bacteria is bile salt tolerant and grows on MSA but has no color change. It is also optochin resistant and highly antibiotic resistant in general.
Enterococcus
What kind of hemolysis does Enterococcus show?
usually non-hemolytic
Enterococcus is enteric but can also colonize in the ____ and can be found in the ___
gut; feces
This disease caused by enterococcus is described as abdominal swelling and tenderness after trauma or surgery
peritonitis
This disease caused by enterococcus is not common but may be acute or chronic. What begins as a nosocomial UTI can lead to bacteremia and furthermore, this disease
endocarditis
What does Viridans Strep look like on a blood agar plate and what kind of hemolysis does it show?
green on blood agar; alpha and non-hemolysis
This type of strep is P-disk resistant and non-pyogenic.
Viridans Strep
Viridans Strep is most prevalent in the ___ cavity but can also be found in ____ and the female ___ tract
oral; URT; genital
Of the more than 30 species in the Viridans Strep class, most are put into 5 groups. For each of the following groups, give the associated disease: Anginosus Mitis Mutans Salvivarius Bovis Ungrouped
Anginosus: abscess in brain, oropharynx or peritoneal cavity
Mitis: subacute endocarditis, sepsis in neutropenic patients, pneumonia -> meningitis
Mutans: dental caries, bacteremia
Salvivarius: bactermia, endocarditis
Bovis: bacteremia associated with GI cancer, meningitis
Ungrouped: bacteremia, meningitis, TSS -> endocarditis
What is the most important virulence factor for Virdians Strep?
glucosyl-transferase (from biofilm on enamel)
This bacteria is generally susceptible to penicillin, metronidazole, chloramphenicol. It is found in normal flora of oral cavity, gut, and skin.
Anaerobic cocci
In regards to anaerobic cocci, for each of the following anatomical locations, give the disease associated with it URT GIT GUT Skin
URT: sinusitis and pleuropulmonary infections
GIT: intra-abdominal infections
GUT: endometritis, pelvic abscesses, and salpingitis
Skin: cellulitis and tissue infections
