Streptococcus

Question 1

What are the characteristics of streptococci?

Answer 1

Gram + and 1 um in diameter; arranged in pairs or chains; usually capsulated and non-motile.

Question 2

Do streptococci form spores?

Answer 2

No.

Question 3

Describe the oxygen using classification of streptococci.

Answer 3

Facultative anaerobes.

Question 4

Do streptococci produce catalase?

Answer 4

No.

Question 5

Are streptococci fastidious?

Answer 5

Yes.

Question 6

Streptococci are classified according to what factors?

Answer 6

Oxygen requirements; serology (Lanciefield Classification); hemolysis on blood agar.

Question 7

What are the classifications of streptococci according to their oxygen requirement?

Answer 7

Anaerobic (Peptostreptococcus); aerobic or facultative anaerobic (Streptococci).

Question 8

Describe the classification of streptococci according to serology.

Answer 8

Based on C-carbohydrate antigen of cell wall; classified into many groups from A-K to H-V; can be one or more species per group.

Question 9

What are the groupable streptococci according to Lanciefield classification?

Answer 9

A, B, and D (more frequent); C, G, and F (less frequent).

Question 10

What are the non-groupable streptococci?

Answer 10

S. pneumoniae (pneumonia); viridans streptococci (S. mutans that causes dental carries).

Question 11

What is the natural habitat of streptococci organisms?

Answer 11

Mucosa of upper respiratory tract; lower urogenital system; intestinal tract; udder.

Question 12

Describe the structure of group A streptococcus cell from outside to inside.

Answer 12

Lipoteichoic acid -> hyaluronic acid capsule -> cell wall -> plasma membrane -> cytoplasm.

Question 13

What is the cell wall of a group A streptococcus cell made from?

Answer 13

Protein antigens M, T, and R; Rhamnose-N-acetylglucosamine; mucopeptide.

Question 14

What are the structural components that allow streptococci to be pathogenic and have virulence factors?

Answer 14

M protein M: interferes with opsonization and lysis of bacteria; lipoteichoic acid: adhesion; F protein: adhesion; hyaluronic acid capsule: acts as camouflage.

Question 15

What are the enzymes of streptococci that act as pathogenic and virulence factors of the bacteria?

Answer 15

Streptokinases; Deoxynucleases; C5a peptidase.

Question 16

What is the role of deoxynucleases and C5a peptidases in streptococci bacteria?

Answer 16

Facilitate the spread of streptococci through tissues.

Question 17

What is the role of pyrogenic toxins as virulence factors for streptococci?

Answer 17

Stimulate macrophages and helper T cells to release cytokines.

Question 18

What are the streptolysins that act as virulence factors for streptococci?

Answer 18

Streptolysin O; streptolysin S.

Question 19

What is the role of streptolysin O as a virulence factor for streptococci?

Answer 19

Lyse red blood cells, white blood cells, and platelets.

Question 20

What is M protein?

Answer 20

Type-specific protein antigen; inhibits binding to phagocytes and is toxic to phagocytic cells; facilitates adherence to host cells (together with lipoteichoic acid).

Question 21

Describe streptolysin S.

Answer 21

Nonantigenic; target cells are RBCs, WBCs, etc.

Question 22

Describe streptolysin O.

Answer 22

Antigenic; deactivated by oxygen.

Question 23

Describe streptokinase A and B.

Answer 23

Antigenic; dissolves clots.

Question 24

Describe streptodornase A to D.

Answer 24

Liquefy pus.

Question 25

Describe hyaluronidase.

Answer 25

Splits hyaluronic acid.

Question 26

Describe C5a peptidase.

Answer 26

Degrades C5a.

Question 27

Describe the pathogenesis of streptococcus.

Answer 27

Infect many animals; causes suppurative infections; infections can be primary or secondary.

Question 28

What are examples of suppurative infections caused by streptococcus?

Answer 28

Mastitis; metritis; polyarthritis; meningitis.

Question 29

What does group A streptococcus cause in humans?

Answer 29

Erythrogenic toxin (scarlet fever), which causes red, sandpaper-like rashes and a sore throat accompanied by 'strawberry-like tongue'; toxic shock syndrome; S. pyogenes.

Question 30

What does S. agalactiae (Group B) cause in cows?

Answer 30

Mastitis.

Question 31

Describe transmission of S. agalactiae.

Answer 31

Transmission within herds is thought to be strictly contagious, i.e. cow to cow; due to insufficient hygiene in milking parlors that results in multiple animals coming into contact with equipment that is contaminated with milk from an infected cow.

Question 32

What are the symptoms of S. agalactiae in cows?

Answer 32

Noticeable changes in milk: flakes and clots in foremilk samples; watery or off-white color; hot, hard udder quarter that is sensitive to touch (absent in some cases).

Question 33

What test is used to check for the presence of S. agalactiae?

Answer 33

CAMP test; blood agar is inoculated at a right angle to staphylococcus but not touching, and it forms a 'CAMP phenomenon' arrowhead.

Question 34

What are two other examples of mastitis-causing streptococcus bacteria besides S. agalactiae?

Answer 34

S. dysgalactiae; S. uberis.

Question 35

Describe S. dysgalactiae in cattle.

Answer 35

Environmental mastitis usually due to contaminations from bedding that is often subclinical; acute mastitis.

Question 36

What is the common name for S. equi subspecies equi?

Answer 36

Strangles.

Question 37

How is S. equi subspecies equi transmitted?

Answer 37

Ingestion or inhalation.

Question 38

Describe the pathogenesis of S. equi subspecies equi.

Answer 38

Abscessed lymph nodes that drain pus; bacteremia: widespread dissemination.

Question 39

How long does immunity last after infection with S. equi subspecies equi?

Answer 39

Up to 5 years following recovery.

Question 40

What is bastard strangles?

Answer 40

Strangles that spreads from primary sites.

Question 41

What is purpura hemorrhagica?

Answer 41

Immune complex disease resulting from type III hypersensitivity to S. equi subspecies equi.

Question 42

What are the characteristic symptoms of equine strangles?

Answer 42

Abscessation of upper respiratory tract; mucoid-mucopurulent discharge, fever, difficulty swallowing; inspirational noise; extended head and neck.

Question 43

What species does equine strangles most commonly affect?

Answer 43

Highly contagious in horses, donkeys, and mules.

Question 44

What is metastatic strangles?

Answer 44

Strangles that results in abscessation in other lymph nodes of the thorax and/or abdomen resulting in severe weight loss.

Question 45

What is the main symptom of purpura hemorrhagica?

Answer 45

Edema of the limbs and brisket and petechial hemorrhages of MM.

Question 46

Who is most commonly affected by purpura hemorrhagica?

Answer 46

Young horses; results in immune-mediated vasculitis.

Question 47

What are the different vaccines available for S. equi?

Answer 47

Attenuated intranasal vaccine; M-protein subunit vaccine.

Question 48

What is the common name for S. equi subspecies zooepidemicus?

Answer 48

Navel ill in foals.

Question 49

Describe the pathogenesis of S. equi subspecies zooepidemicus.

Answer 49

Umbilical infection: hematogenous spread; acute fatal septicemia in foals less than a week old; hypopyon: leakage of fluids into the anterior chamber of the eye.

Question 50

What does S. equi subspecies zooepidemicus cause in older horses?

Answer 50

Suppurative polyarthritis, meningitis, pneumonia, ophthalmitis, etc.

Question 51

What treatment of S. equi subspecies zooepidemicus may result in recovery?

Answer 51

Early.

Question 52

What does S. equi subspecies zooepidemicus cause in mares?

Answer 52

Placentitis and abortion.

Question 53

S. suis are ________ antigens with ______ serotypes.

Answer 53

Capsular with 35 serotypes.

Question 54

Of the 35 serotypes of S. suis, which one accounts for the majority of swine diseases?

Answer 54

Serotype 2.

Question 55

How is S. suis transmitted?

Answer 55

Via inhalation, ingestion, or contact.

Question 56

In what type of animal is S. suis most common?

Answer 56

Localized or septicemic disease most common in growing pigs.

Question 57

What are the symptoms of S. suis?

Answer 57

Pericarditis; bronchopneumonia; meningitis; polyarthritis: knuckling; zoonotic for septicemia and meningitis; congestion due to lymphadenopathy or pus at the base of the cerebellum.

Question 58

What issues does S. suis cause with the lungs?

Answer 58

Edema/petechiae; abscesses on lungs; fibronecrotic pneumonia.

Question 59

S. porcinus belongs to what classification group?

Answer 59

Lanciefield classification group E.

Question 60

S. porcinus was previously responsible for what?

Answer 60

Streptococcal lymphadenitis; jowl abscesses; cervical clinical entity in growing pigs in USA.

Question 61

Describe present-day S. porcinus.

Answer 61

Found in almost 20% of tonsils in slaughterhouses; pathology is not frequently seen, but the pathogen is still prevalent in swine.

Question 62

What does S. canis cause in dogs?

Answer 62

Opportunistic pathogen that causes wounds, urinary and mammary infections, and necrotizing fasciitis.

Question 63

Necrotizing fasciitis results from S. canis especially when what are used for treatment?

Answer 63

Quinolones.

Question 64

What does S. canis cause in cats?

Answer 64

Respiratory and soft tissue infections/abscesses.

Question 65

What does S. bovis cause?

Answer 65

Rumen acidosis due to lactose fermentation.

Question 66

Chickens are mostly infected by what streptococcal infection?

Answer 66

Enterococci.

Question 67

How is S. suis treated in pigs?

Answer 67

Serotype 2 bacterin.