Streptococci

Question 1

Define streptococcus?

What are disorders of streptococcus?

Answer 1

gram-positive aerobic organisms

cause many disorders, including pharyngitis, pneumonia, wound and skin infections, sepsis, and endocarditis.

Question 2

What are disorders caused by group A beta hemolytic?

Answer 2

group A beta hemolytic streptococci may include rheumatic fever and glomerulonephritis.

Question 3

What are classification of streptococcus? Define each of them.
Which media is used for streptococcus

Answer 3

• Beta-hemolytic streptococci produce zones of clear hemolysis around each colony.
• Alpha-hemolytic streptococci (commonly called viridans streptococci) are surrounded by green discoloration resulting from incomplete hemolysis.
• Gamma-hemolytic streptococci are non-hemolytic.

they are grown on sheep blood agar

Question 4

What is subsequent classification of streptococcus?

And depend on what?

Answer 4

Based on carbohydrates in the cell wall, divides streptococci into Lancefield groups A through H and K through T ( Lancefield Classification).

Question 5

Some streptococcus don’t response to lancefield classification?

Answer 5

Streptococcus pneumoniae

Question 6

What is streptococcus virulence factor?

Answer 6

Streptomycins, DNAases, and hyaluronidase

Question 7

How does streptococcus stimulate immune system?

Answer 7

release exotoxins that activate certain T cells, triggering release of cytokines, including tumor necrosis factor-alpha, interleukins, and other immuno-modulators.

Question 8

Which streptococcus is most pathogenic and from which class?

Answer 8

S. Pyogenes

which is beta-hemolytic and in Lancefield group A (GABHS)

Question 9

What are diseases caused by GABHS?

Answer 9

• Pharyngitis
• Skin infections

-rheumati fever, acute glomerulonephritis

Question 10

How can lymph nodes are affected by GABHS?

Answer 10

GABHS can spread through the affected tissues and along lymphatic channels (causing lymphangitis) to regional lymph nodes (causing lymphadenitis).

Question 11

What are suppurations complications of GABHS?

Answer 11

GABHS can also cause local suppurative complications, such as peri-tonsillar abscess, otitis media, sinusitis, and bacteremia.

Question 12

Which streptococcus cause pharyngitis?

Answer 12

GABHS

Question 13

Define scarlet fever

Answer 13

Scarlet fever is caused by group A streptococcal strains that produce an erythrogenic toxin, leading to a diffuse pink-red cutaneous flush that blanches with pressure.

Question 14

Explain streptococcal skin infection?

Answer 14

Impetigo is a superficial skin infection that causes crusting or bullae.

Erysipelas is a superficial cellulitis that also involves the lymphatics. Patients have shiny, red, raised, indurated lesion caused by GABHS,

Cellulitis involves the deeper layers of skin and may spread rapidly, toxins produced mainly by group A streptococci.

Question 15

T/F Necrotizing fasciitis is prevalent among IV drug abusers.

Answer 15

True

Question 16

What are symptoms of necrotizing fasciitis?

Answer 16

1 Fever
2 exquisite localized pain
3 diffuse and local erythema
4-Thrombosis
5-ischemic necrosis
6 - shock and renal dysfunction.

Question 17

What is cause of streptococcal toxic shock syndrome?

Answer 17

Is similar to that caused by S. aureus, may result from toxin-producing strains of GABHS and occasionally from other streptococci.

Question 18

What is rheumatic Fever caused by streptococci?
How to diagnose it?
How to prevent it?

Answer 18

An in flomevertary caused because of untreated GABH5 pharyngitis.

Diagnosis of a first episode is based on a combination of arthritis, carditis, chorea, specific cutaneous manifestations,

One of the most important reasons for treating GABHS pharyngitis (strep throat) is to prevent rheumatic fever.

Question 19

What is poststreptococcal acute glomeruloneptritis?

What is side effect of treatment glomerulonephritis?

Answer 19

After a throat or skin infection with one of these strains, about 10 to 15% of patients develop acute glomerulonephritis

Antibiotic treatment of GABHS infection has little effect on development of glomerulonephritis.

Question 20

What IS PANDA syndrome

Answer 20

(pediatric autoimmune neuropsychiatric disorder associated with group A streptococci) refers to a subset of obsessive disorders or tic disorders

Question 21

T / F

Certain forms of psoriasis (eg, guttate) may also be related to beta-hemolytic streptococcal infections.

Answer 21

True

Question 22

T/F pneumococcus capsule consists of a complex polysaccharide that determines serologic type and contributes to virulence and pathogenicity.

Answer 22

True

Question 23

What is most important component of pneumococcus?

What are most important serotype. of pneumococcus?

Answer 23

pneumococcus capsule consists of a complex polysaccharide that determines serologic type

1 Serotype 3 strains, which are more heavily encapsulated and tend to form more mucoid colonies than other serotypes,

2 Serotype 19A, which is highly virulent and multidrugresistant,

Question 24

Which patients are more susceptible to pneumococcal infection?

Answer 24

1-chronic illness
2-immunosuppression
3-sickle cell disease
4-Smokers
5-Alaskan natives

Question 25

What is best drug fo uncomplicated or mild infection of streptococcus?
Which drugs used during resistant?

Answer 25

a beta- lactam or macrolide antibiotic.

cephalosporin (eg, ceftriaxone, cefotaxime, ceftaroline), a respiratory fluoroquinolone(eg, moxifloxacin, levofloxacin, gemiflox acin), and/or a tetracycline (eg, omadacycline).

Question 26

What ‘is drug for severe pneumocaccul pneumonia?

Answer 26

combination therapy (eg, macrolide plus beta-lactam).

Question 27

Which vaccine is recommended for children to prevent streptococcal infection?.

Answer 27

Routine vaccination with PCV13 is recommended for all children aged 2 months through 6 years

Question 28

Streptopneumonia causes which disease?

Answer 28

MOPS
Meningitis
Otitis
Pneumonia
Sinusitis did