STREPTOCOCCUS Flashcards
catalase (-)
alpha hemolytic
optochin sensitive
Streptococcus pneumoniae
catalase (-)
alpha hemolytic
optochin resistant
Viridans streptococci
catalase (-)
beta hemolytic
bacitracin sensitive
Streptococcus pyogenes
catalase (-)
beta hemolytic
bacitracin resistant
Streptococcus agalactiae
catalase (-)
gamma hemolytic
group D streptococci
Produces SCARLET FEVER
Erythrogenic toxin
Highly antigenic
Causes AB formation
Streptolysin O (oxygen labile)
Superantigen similar to TSST
Pyrogenic Exotoxin A
Protease that rapidly destroys tissue
Exotoxin B
Responsible for necrotizing fasciitis
Document antecedent PHARYNGITIS
anti-streptolysin (ASO)
Document antecedent SKIN INFECTIONS
anti-DNAse B
Antibodies decrease efficacy of streptokinase in managing MI
anti-streptokinase
Skin and Soft Tissue Infections caused by Streptococcus pyogenes
Impetigo contagiosa
Erysipelas - superficial
Cellulitis - facilitated by HYALURONIDASE (spreading factor)
Necrotizing fasciitis - facilitated by exotoxin B; Fournier’s gangrene
MC bacterial cause of sore throat
Streptococcus pyogenes
inflammation, exudate, fever, leukocytosis and tender CLAD
PYOGENIC COMPLICATIONS: peritonsillar and retropharyngeal (Quincy) abscess, otitis, sinusitis, meningitis
Due to ERYTHROGENIC TOXIN
fever, strawberry tongue, centrifugal rash (sandpaper like), PASTIA LINES, desquamation
Scarlet Fever
-postpharyngitic
Similar but milder than S. aureus
Due to PYROGENIC EXOTOXIN A
RECOGNIZABLE SITE of pyogenic inflammation
blood cultures (+)
Streptococcal Toxic Shock Syndrome
Cross reacting antibodies to M proteins and antigens of joint, heart and brain tissue
Acute Rheumatic Fever
-postpharyngitic
JONES CRITERIA
- pancarditis
- erythema marginatum
- chorea (sydenham)
- carditis (pancarditis)
- subcutaneous nodules
M protein incites immune complex deposition on the GBM
hypertension, periorbital edema, HEMATURIA
Glomerulonephritis
-post impetigo (M12 type) or postpharyngitic
8/M presents w/ fever, migrating joint pains in the knees and elbows, has raised erythematous serpentine-like lesions on his back
Patients clinical presentation is most likely due to which pathophysiology mechanism?
Cross-reaction of antibodies to bacterial antigens w/ self antigens leading to cytotoxicity
MCC of NEONATAL pneumonia, sepsis and meningitis
Streptococcus agalactiae (Group B Streptococci)
PREDISPOSING FACTORS:
- intrapartum fever T>38 C
- PROM (>18h)
- vaginal colonization
- complement deficiency
All pregnant women should be screened for GBS colonization at
35-37 weeks AOG
chemoprophylaxis - IV Penicillin or Ampicillin 4 hrs prior to delivery
Major cause of ADULT PNEUMONIA
MCC of otitis media
MCC of ADULT MENINGITIS
Streptococcus pneumoniae
- lancet shaped
- encapsulated
Quellung reaction
Capsular Antigen Swelling Test
POSITIVE
-(+) capsular swelling when mixed with a small amt of antiserum and methylene blue
Pathogenesis (Streptococcus pneumoniae)
CAPSULE - retards phagocytosis
IgA PROTEASE - for colonization
C-SUBSTANCE - reacts w/ CRP
Responsible for the formation of DENTAL CARIES
S. mutans - can produce BIOFILM
Responsible for SUBACUTE BACTERIAL ENDOCARDITIS (SBE)
MCC of subacute and native valve endocarditis
S. sanguis
Responsible for BRAIN ABSCESSES
S. intermedius
Pathogenesis (Viridans streptococci)
glycocalyx enhances adhesion to DAMAGED HEART VALVES
protected from host defenses w/n VEGETATIONS
While testing various strains of Streptococcus pneumoniae, a researcher discovers that a certain strain of this bacteria is unable to cause disease in mice when deposited in their lungs. What physiological test would most likely to deviate from normal in this strain of bacteria as opposed to a typical strain?
Quellung Reaction
34/M, heroin user, presents w/ a 3 day hx of fever T>39, chest pain, “pinching” in character, nausea, vomiting. Troponins are low. CKMB negative. ECG shows sinus tachycardia. Blood culture on 2 sites were positive. Past History: Tricuspid valve repair in 2003. What is the most likely diagnosis?
Acute Endocarditis
ER na ER ang itsurahan
Subacute Endorcarditis
- gradual progression
- ndi pang ER baks
Hydrolyzes esculin in bile-esculin agar (BEA)
positive PYR test
Group D Streptococci
E. faecalis - can GROW in 6.5% NaCl
S. bovis - CANNOT grow in 6.5% NaCl
Infective Endocarditis
Enterococcus faecalis
PREDISPOSITION:
GIT surgery
Marantic Endocarditis
-sterile form of endocarditis
Streptococcus bovis
-risk factor in developing CANCER
Cefalexin may be useful to treat which infection
a. Enterococcal endocarditis
b. Listeria meningitis
c. MRSA pneumonia
d. Hidradenitis suppurativa
e. All of the above
Hidradenitis suppurativa
NONE of the Cephalosporins are active against the ff:
Enterococci
Listeria monocytogenes
MRSA
34/M, heroin user, presents w/ a 3 day hx of fever T>39, chest pain, “pinching” in character, nausea, vomiting. Emergency appendectomy was done. Troponins are low. CKMB negative. ECG shows sinus tachycardia. Blood culture on 2 sites were positive. (+) bacterial vegetations on tricuspid area are seen in TEE. What is the most likely diagnosis?
Enterococcus spp
34/M, heroin user, presents w/ sudden onset of fever T>39, vague abdominal pain, nausea and vomiting. Emergency laparotomy was done. Diagnosis of COLON CANCER was noted. Troponins are low. CKMB negative. ECG shows sinus tachycardia. Blood culture on 2 sites were positive. (+) STERILE vegetations on tricuspid area are seen in TEE. What is the most likely diagnosis?
Streptococcus bovis
