Streptococcus

Question 1

Streptococci grow well on … and many species secrete.. , which produce patterns of … around the colonies.

Answer 1

blood agar
hemolysins
hemolytic zones

Question 2

Based on these ….streptococcii classified in to three groups:

Answer 2

hemolytic zones,
Alpha- hemolytic streptococci (a zone with an opaque greenish color), e.g. S. pneumonia e, S. viridans.
Beta- hemolytic streptococci (a clear zone of hemolysis surrounding the colony).
Gamma- hemolytic streptococci (no hemolytic zone surrounding the colony), e.g. S. faecalis.

Question 3

β- hemolytic group are differentiated according to … located in the streptococcal cell wall (…) from A to U.

Answer 3

carbohydrate antigens
Lancefield groups

Question 4

The most important beta hemolytic human pathogens group:

Answer 4

Group A –β hemolytic streptococci (GAS) S.pyogenes.
Group B - β hemolytic streptococci (GBS) S. agalactiae.

Question 5

Alpha hemolytic streptococcal Is growing only on …. supplemented with 5% blood.

Answer 5

enriched media

Question 6

The virulent strains of alpha hemolytic streptococcal possess a prominent … that plays an important role in the pathogenesis of pneumococcal diseases by retarding the rate of ….
The capsule composed of … and is … ( capable of stimulating antibody synthesis).

Answer 6

capsule
phagocytosis
polysaccharide
antigenic

Question 7

Infection of alpha hemolytic streptococcal can be … by droplets, or … from the nasopharynx.

Answer 7

exogenous
endogenous

Question 8

About 40-70% 0f healthy adults carry the organism alpha hemolytic streptococcal in ….

Answer 8

nasopharynx

Question 9

Pneumococci have many virulence factors:

Answer 9

Polysaccharide capsule (antiphagocytic).
IgA protease (traps bacteria that enveloped in mucus and prevent their removal by the action of ciliated epithelial cells).
Pneumolysin toxin (binds to the host cell membrane, creates pores and causing cell lysis).

Question 10

Pneumococcal diseases are most commonly associated with…… or other diseases interfere with bacterial clearance.

Answer 10

viral diseases (influenza, measles)

Question 11

Streptococcus Viridans (S. viridans)
Also known as ……

Answer 11

oral streptococci.

Question 12

Streptococcus Viridans (S. viridans)
Commonly found orally, including ….

Answer 12

S.mutans, S.mitis, S. sanguis and S. salivarius.

Question 13

Streptococcus Viridans (S. viridans)
The organisms are most frequently associated with… (also known as… ) as a result of ….

Answer 13

dental caries
tooth decay
tooth enamel destruction.

Question 14

Streptococcus Viridans (S. viridans)
After tooth extraction, bacteria reach bloodstream and cause 50-70% ….

Answer 14

endocarditis disease.

Question 15

Streptococcus pyogenes ( S. pyogenes)
It’s also known as the …..

Answer 15

flesh eating bacteria.

Question 16

Hyaluronic acid capsule of S.pyogenes

Answer 16

non-immunogenic

Question 17

M protein (surface protein ):
Of s.pyogenes

Answer 17

major virulence factor and strongly antiphagocytosis.

Question 18

M protein (surface protein ): - It associated with …… and …….

Answer 18

rheumatic heart disease
glomerulonephritis

Question 19

• A person can have repeated infection with S. pyogens due to…

Answer 19

the presence of more than 80 types of M protein.

Question 20

F protein: Is protein binds to ….. in epithelial cells, not leave, and it’s necessary for …..

Answer 20

host fibronectin
invasion

Question 21

Pyrogenic exotoxins (SPE):
Also called ……

Answer 21

erythrogenic toxins.

Question 22

Type of Pyrogenic exotoxins (SPE)

Answer 22

SpeA, SpeB, SpeC).

Question 23

SpeB act as ..

Answer 23

superantigens, interacting with both macrophage & helper –T cell causing cytokines releasing, associated with shock and organ failure.

Question 24

SpeA & C, responsible for …

Answer 24

observed skin rash in scarlet fever disease.

Question 25

… , responsible for bacterial hemolytic activity ,(s.pyogenes

Answer 25

streptolysins: Enzymes

Question 26

Streptolysin O, which is …..and…. induce ….. after S. pyogenes infection.

Answer 26

oxygen labile
antigenic enzyme;
antibody formation (ASO)

Question 27

Streptolysin S, which is …..and….. can lyse erythrocytes, leukocytes and platelets by binding to the cell surface .

Answer 27

oxygen stable
non-immunogenic,

Question 28

Streptokinase: Also known as …

Answer 28

fibrinolysin

Question 29

Group A streptococci infections affect all ages with …..

Answer 29

peak incidence between 5-15 age,

Question 30

Bacteria such as α- hemolytic and non-hemolytic streptococci are able to produce antibiotic –like substances called….. , which …..

Answer 30

bacteriocins
suppress group A streptococcus growth.

Question 31

Scarlet fever: Is complication of streptococcal pharyngitis, resulting from ……..

Answer 31

pyogenic exotoxins A-C production and diffusing to the blood.

Question 32

Impetigo ( pyoderma): It’s a superficial localized skin infection, mostly among children between (2-6) years old, it also known ……

Answer 32

school sores

Question 33

Puerperal fever: Also known ….

Answer 33

childbed fever.

Question 34

Necrotizing fasciitis:
Also known as ….

Answer 34

flesh-eating or streptococcal gangrene.

Question 35

Streptococcus agalactiae (S. agalactiae)
Is a species of the normal flora of the…

Answer 35

female urogenital tract.

Question 36

Streptococcus agalactiae (S. agalactiae)

Early perinatal infection causes ….., with high mortality.

Answer 36

pneumonia or septicemia

Question 37

Streptococcus faecalis ( enterococcus faecalis):
Is a Gram-positive, commensal bacterium inhabiting the …. of humans and other mammals.

Answer 37

gastrointestinal tracts

Question 38

E. faecalis can cause ….. in humans, especially in the ….

Answer 38

life-threatening infections
nosocomial (hospital) environment.

Question 39

E. faecalis is a nonmotile, facultatively anaerobic microbe; it ferments…. , and does not produce a catalase reaction with hydrogen peroxide.

Answer 39

glucose without gas production

Question 40

Enterococci survive….. including …….and…..

Answer 40

very harsh environments
extreme alkaline pH (9.6
and salt concentrations.