Lesson 4a: Corynebacterium species

Question 1

is a facultative intracellular pathogen capable of surviving and replicating in phagocytes whose virulence is linked to its cell wall lipid and to the production of an exotoxin, phospholipase D that enhances its survival and multiplication in the host.

Answer 1

C. pseudotuberculosis

Question 2

Diphtheria toxin present in raw milk cows may implicate public health

Answer 2

C. ulcerans and C. pseudotuberculosis

Question 3

caused by the non-nitrate-reducing biotype of C. pseudotuberculosis in goats, sheep, and cattle.

Answer 3

Caseous lymphadenitis

Question 4

caused by the nitrate-reducing biotype of C. pseudotuberculosis in horses and cattle. Prevalent in countries with temperate weather

Answer 4

Ulcerative lymphangitis

Question 5

Caused by C. renale group. The stress of parturition and the short urethra in the cow predispose to infection of the urinary tract.

Answer 5

Bovine pyelonephritis

Question 6

also called pizzle rot common in merino sheep and angora goats, is caused by C. renale and is characterized by ulceration around the preputial orifice, with a brownish crust developing over the lesion

Answer 6

ulcerative balanoposthitis

Question 7

aerobic bacteria have an electron transport system. contain an enzyme called cytochrome.

Answer 7

oxidase test

Question 8

used to determined the ability of an organism to reduce nitrate to nitrite using the enzyme nitrate reductase

Answer 8

nitrate reduction test

Question 9

Corynebacterium species

Answer 9

• gram positive
• fastidious, requiring enriched media
• occur singly
• commensals on mucous membranes
• cause pyogenic infection
• non-motile facultative anaerobes
• catalase-positive, oxidase negative

Question 10

Corynebacterium species

Answer 10

• gram-positive, pleomorphic bacteria
• fastidious, requiring enriched media
• occur singly, in palisades of parallel cells and in angular clusters resembling Chinese characters in stained smears
• majority are commensal on mucous membranes
• cause pyogenic infections
• non-motile facultative anaerobes
• catalase-positive, oxidase-negative
• usual habitat: mucous membranes