Genus Corynebacterium

Question 1

Describe the appearance of corynebacteria.

Answer 1

Gram + pleomorphic long rods that are swollen on one end (club shaped). They lie in small groups joined together at angles to each other, giving a characteristic Chinese-letter arrangement. Metachromatic granules.

Question 2

What is the habitat of corynebacteria?

Answer 2

Common inhabitants of skin and mucous membranes of animals, causing opportunistic, pyogenic infections.

Question 3

Describe biotype 1 C. pseudotuberculosis.

Answer 3

Nitrate-negative strains that cause caseous lymphadenitis in sheep and goats.

Question 4

Describe biotype 2 C. pseudotuberculosis.

Answer 4

Nitrate-positive strains that cause ulcerative lymphangitis in cattle and horses and pectoral abscess in horses.

Question 5

What is the common presentation of C. pseudotuberculosis in goats, sheep, and camels?

Answer 5

Caseous lymphadenitis.

Question 6

What is the common presentation of C. pseudotuberculosis in cattle?

Answer 6

Mastitis.

Question 7

What is the common presentation of C. renale in cattle?

Answer 7

Pyelonephritis, cystitis.

Question 8

What is the common presentation of C. renale in pigs?

Answer 8

Kidney abscesses.

Question 9

What is the common presentation of C. renale in male sheep?

Answer 9

Balanoposthitis (pizzle rot).

Question 10

What is the common presentation of C. cystitidis in cattle?

Answer 10

Cystitis, pyelonephritis.

Question 11

What is the common presentation of C. pilosum in cattle?

Answer 11

Cystitis, pyelonephritis.

Question 12

What is the common presentation of R. equi in foals 4-12 weeks?

Answer 12

Bronchopneumonia.

Question 13

What is the common presentation of R. equi in older foals?

Answer 13

Abscesses.

Question 14

What is the common presentation of C. diphtheriae in humans?

Answer 14

Diphtheria.

Question 15

Describe caseous lymphadenitis in sheep and goats.

Answer 15

Chronic disease characterized by abscessation of superficial and internal lymph nodes and parenchymatous organs.

Question 16

Describe the transmission of caseous lymphadenitis in sheep and goats.

Answer 16

Mainly via infection of broken or abraded skin. The organism may also be ingested or inhaled.

Question 17

What are the virulence factors of C. pseudotuberculosis?

Answer 17

Cell wall lipid and phospholipase D exotoxin.

Question 18

How do cell wall lipids act as a virulence factor for C. pseudotuberculosis?

Answer 18

Protects against intracellular killing.

Question 19

How do phospholipase D exotoxins act as a virulence factor for C. pseudotuberculosis?

Answer 19

Lysis leukocytes and endothelial cells; induces protective antibodies.

Question 20

What is the common name for caseous lymphadenitis?

Answer 20

“Thin ewe or thin goat syndrome”.

Question 21

Describe the pathogenesis of C. pseudotuberculosis.

Answer 21

Enlargement and abscessation of superficial and internal lymph nodes. Can develop bacteremia which leads to abscessation of various internal organs.

Question 22

What will the appearance of C. pseudotuberculosis be after 24 hours of incubation?

Answer 22

Small, white colonies.

Question 23

What will the appearance of C. pseudotuberculosis be after 48 hours of incubation?

Answer 23

Narrow zone of hemolysis around colonies.

Question 24

What are the synonyms for ulcerative lymphangitis in horses?

Answer 24

Pigeon fever, pigeon breast, biotype 2 C. pseudotuberculosis.

Question 25

How is ulcerative lymphangitis in horses transmitted?

Answer 25

Infection of abraded skin.

Question 26

What are the clinical signs of ulcerative lymphangitis in horses?

Answer 26

Enlarged, abscessed lymphatic vessels; limbs are edematous.

Question 27

The Corynebacterium renale group consists of which organisms?

Answer 27

C. renale, C. cystitidis, C. pilosum.

Question 28

Organisms of the Corynebacterium renale group cause what condition in bovine?

Answer 28

Contagious bovine pyelonephritis.

Question 29

How is contagious bovine pyelonephritis transmitted?

Answer 29

Contact with contaminated urine.

Question 30

What are the factors that predispose an animal to contagious bovine pyelonephritis?

Answer 30

High protein diet, obstruction of the urinary tract.

Question 31

Pathogenesis of contagious bovine pyelonephritis is via what mechanism?

Answer 31

Fimbriae-mediated adhesion of organisms.

Question 32

Describe the factors of the pathogenesis of contagious bovine pyelonephritis.

Answer 32

Ascending infection of urinary tract; urease produces ammonia from urea which causes elevated pH and inflammation of the mucosa.

Question 33

What is the pathology of contagious bovine pyelonephritis?

Answer 33

Enlarged kidneys; thickened ureteral and bladder walls; abscessation.

Question 34

What are the signs/symptoms of contagious bovine pyelonephritis?

Answer 34

Passage of urine with blood or pus; dysuria; palpable abnormalities per rectum of affected organs.

Question 35

How can you confirm a diagnosis of contagious bovine pyelonephritis?

Answer 35

Culture of urine and rectal palpation of affected organs.

Question 36

Which animals are most likely to get contagious bovine pyelonephritis?

Answer 36

Often seen after parturition; multiparous cows most at risk; rare in bulls.

Question 37

What do the following colors of a urease test indicate: pink, orange, yellow?

Answer 37

Pink: positive urease production; orange: uninoculated tube; yellow: negative urease production.

Question 38

Ulcerative posthitis in sheep and goats is due to infection by what organisms?

Answer 38

C. pilosum and C. cystitidis.

Question 39

Describe the pathogenesis of ulcerative posthitis.

Answer 39

High-protein diet; hydrolysis of urea causing increased ammonia levels; ulcerated preputial orifice with purulent debris; phimosis, urea toxicity, etc.

Question 40

Which breeds are more susceptible to ulcerative posthitis?

Answer 40

Angora rams and Merino rams.