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)