Streptococci I and II

Question 1

General Characteristics of Streptococci

Answer 1

Gram + Cocci in chains/pairs, facultative anaerobe, hemolysis, catalase negative, no flagella (along with all cocci bactera –> non motile)

Question 2

Hemolysis (blood agar plates)

Answer 2

alpha = incomplete (agar appears green)
Beta = complete (clear zone)
Gama = no hemolysis

Question 3

Streptococcus Pyogenes

Answer 3

Group A, very common, Beta hemolytic, BACITRACIN SENSITIVE (only Strep that is sensitive), haluronic acid capsule (minimal role in antiphagocytic)

Has M-Protein (highly antiphagocyutic that prevents opsinization by complemen)

Question 4

Streptococci Extracellular products

Answer 4

Streptolysisn O: lyses RBCs, WBC
Streptolysin S: poorly immunogenic 
Streptokinase: degrades fibrin 
Streptodornase: degrade DNA, liquifies pus 
Haluronidase: augments invasion 
Protease: aids invasion 
C5a peptidase: inhibits chemotaxis 

All these enzyme makes the bacteria very invasive due to them degrading tissue

Question 5

Pharyngitis

Answer 5

Strep Throat, mainly by Group A, superficial (epithelial tissue), fever, tonsilar exudates, sometimes scarlet fever (strawberry tongue –> peals off to become red tongue)

Diagnose: “Rapid strep” tests for S. Pyogenes (not all the other Streph), 75% woks, still need to send culture to lab

Question 6

Impetigo

Answer 6

Skin infection, Due to Group A, epithelial tissues, “honey crusted” discharges, crusty lesions, NO BLISTERS (Blisters Impetigo due to Staph. aureus since they have exfolitan)

Due to insect bites, scratches, Chicken pox

Question 7

Invasive (deep or vital organs) disease of Streph. Pyogens (very dangerous)

Answer 7

Peurperal Spesis = “Child bed fever” (due to Med students not washing hands)
Erysipelas (Cellulitis) = red cellulitis
Necrotizing fasciitis = deep cutaneous, rapidly spreading infection (flesh eating bacteria)
Lymphangitis, lymphadenitis (spreading though lymp vesicles)
Streptococcal spesis/Streptococcal toxic shock syndrome = multiorgan failure

Question 8

Acute Poststreptococcal Glomerulonephritis

Answer 8

Either after impertigo or pharyngitis
Hematuria, edema, hypertension
Type 3 hypersensitivity –> antigen bodies aganist bacteria deposit in the kidney –> kidney damage

Question 9

Rheumatic Fever

Answer 9

1-3 weeks after Pharyngitis only
arthritis, carditis (chronic)
Prevented by antibiotic treatment (Penicillin)
ASO, ADB titers important in making diagnosis

Question 10

Group B

Answer 10

1 cause of Neonatal Menigitis and Neonatal Sepsis then any other bacteria

S. Agalactiae
Beta hemolytic , Bacitractin disk resistance, CAMP test done, flora of vigninal and anorectal area

Question 11

CAMP Test

Answer 11

Diagnosis test for Group B

Question 12

Group D

Answer 12

Enterococcus faecalis and Enterococcus faecium (GI flora)
Gama hemolytic
Cause: UTI, peritoneal cavity infections, endocarditis (only in damaged tissue valves)

Question 13

Laboratory Identification for Group D

Answer 13

gama hemolytic, Hydrolyze bile esculin, grow in high 6.5% NaCl levels, High degree of drug resistance (due to antibiotic we eat)

Esculin (dark = positive test) = definitive test for

Question 14

Virdans Streptococci

Answer 14

all alpha hemolytic (except for S. Pyogenase)
normal flora of upper respiratory track and mouth 
Produces BIOFLIMS (also produced by Staph, Epidermidus)   --> allows it to sticks to slippery surfaces.

Question 15

Conditions Caused by Virdans Streptococci

Answer 15

Able to sit on teeth and tooth decay (Strep. Mutans)
Dental work –> bacteria enters blood stream –> subacute bacterial endocarditis (symptoms = splinter hemorrhages)

Take Penicillin before dental work if you have heart problems

Question 16

Strep Pneumo

Answer 16

not in a group, lancer shaped, normally in phrarix and larynix, alpha hemolysis

Question 17

Diagnosis Test for Strep Pneumo

Answer 17

Optochin disk (not an antibiotic) = diagnostic test (positive = death of bacteria)

Question 18

Strep. Pneumoniae Predisposing Conditions

Answer 18

Influenza, COPD, Congestive Heart Failure, Alcoholism (1st cause of phenumonia), Asplenia (spleen can’t clear blood), age (65+)

Question 19

Strep. Pneumococcus Pathogenesis

Answer 19

IgA Protease (allows to adhere to mucosal surfaces), Capsule, Pneumolysisn O (damages tissue)

Question 20

Phenumonia due to Strep. Pneumococcus

Answer 20

Bacterial Phenumonia (most common cause), Typical Pheumonia (high fever, major chills, bed ridden, rusty sputum),

Atypical Pneumonia (dry hacking cough, no sputum, coughing long time, also called “walking Phenumonia”)

Question 21

Menigits due to Strep. Pneumococcus

Answer 21

Most common cause of adult bacterial meningitis (High PMNs, protein, low glucose in CSF

Most meningitis is due to viral causes (normal glucose, slight high protein, mainly monocytes and lymphocytes)

Question 22

Otitis media and sinusitis in children

Answer 22

Most common cause of ear infections