Trueperella, Rhodococcus, Listeria, Erysipelothrix

Question 1

what phylum do Trueperella (Arcanobacterium) pyogenes and Rhodococcus equi belong to?

Answer 1

Actinobacteria

Question 2

what phylum do Listera spp. and Erysipelothrix rhusiopathiae belong to?

Answer 2

Firmicutes

Question 3

Trueperella spp.
gram - ?
morphology - ?
spore - ?

Answer 3

gram - positive
morphology - bacilli
spore - non-spore forming

Question 4

Are trueperella spp. commensal or parasitic? what part of the body?

Answer 4

commensal - mucous membranes of mammals

Question 5

what bacteria inhabits the upper respiratory, urogenital, and GI tracts of ruminants, swine, and other mammals and is a Actinobacteria?

Answer 5

Trueperella pyogenes

Question 6

How does Trueperella pyogens become an opportunistic pathogen that causes disease?

Answer 6

traumatic inoculation, secondary infection

Question 7

what type of lesions does T. pyogenes cause? where?

Answer 7

suppurative in many organs/tissues

Question 8

what virulence factors does T. pyogenes have?

Answer 8

pyolysin O - cytotoxic to macrophages, neutrophils, RBCs
Neuraminidase - binds to host cell and extracellular matrix

Question 9

what pathogen acts a synergistic pathogen in bovine liver abscesses?

Answer 9

T. pyogenes

Question 10

How is T. pyogenes spread throughout the body?

Answer 10

Hematogenous dissemination

Question 11

How does an infection with T. pyogenes present in swine?

Answer 11

septic arthritis - often after farrowing

Question 12

How does an infection with T. pyogenes present in cattle?

Answer 12

severe mastitis - often heifers and dry cows

Question 13

what is this cow most likely infected by?

Answer 13

T. pyogenes

Question 14

How is T. pyogenes transmitted?

Answer 14

horn flies, teat contact with contaminated environment or contaminated milking equipment

Question 15

How is T. pyogenes diagnosed?

Answer 15

presumptive - clinical findings and gram + rods in exudate smear
definitive - culture & species ID of bacterium from clinical samples

Question 16

What type of T. pyogenes infections do not respond well to antibiotics?

Answer 16

in vivo (abscess encapsulation)

Question 17

what are the reservoirs of Rhodococcus equi?

Answer 17

soil and intestinal tracts and feces of healthy animals

Question 18

what age of horses is Rhodococcus equi primarily an opportunistic pathogen?

Answer 18

young foals

Question 19

what does R. equi cause?

Answer 19

granulomas, pyogranulomas, and abscesses

Question 20

What is the significance of Vap proteins in R. equi?

Answer 20

protect against phagocytic killing
survive and grow inside macrophages (facultative intracellular pathogens)

Question 21

How do foal’s lungs infected with R. equi present?

Answer 21

pyogranulomatous bronchopneumonia

Question 22

Is R. equi infection limited to the lungs?

Answer 22

No - lesions can occur in pulmonary lymph nodes, mesenteric lymph nodes, intestines, and other extra pulmonary sites

Question 23

How is R. equi diagnosed?

Answer 23

presumptive - history, clinical findings, gram + pleomorphic cells within macrophages
definitive - culture and ID bacterium (molecular ID looking for vapA gene)

Question 24

what is a findings in a tracheal wash that would indicate an infection with R. equi?

Answer 24

gram + pleomorphic cells within macrophages

Question 25

what is the PCR for R. equi looking for?

Answer 25

vapA gene

Question 26

what strain of Listeria causes septicemia, abortion, and CNS infections in mammals?

Answer 26

L. monocytogenes

Question 27

what is the transmission of L. monocytogenes?

Answer 27

ingestion of contaminated food and vertical transmission in utero

Question 28

what are virulence factors of L. monocytogenes?

Answer 28

adhesins, listeriolysin O, grow inside phagocytic and non-phagocytic cells

Question 29

what is the toxin produced by L. monocytogenes? what does it do?

Answer 29

listeriolysin O - lets bacteria break out of phagocyte and spread to other cells

Question 30

what is the benefit of L. monocytogenes transferring cell to cell?

Answer 30

reduce exposure to humoral defenses

Question 31

How is Listeriosis diagnosed?

Answer 31

Presumptive - gram + rods in smears Definitive - culture and ID bacterium

Question 32

This calf is experience facial drooping, excess salivation, and leaning to one side- what is wrong and what caused it?

Answer 32

brainstem encephalitis due to listeriosis

Question 33

what is the most important reservoir of Erysipelothrix rhusiopathiae?

Answer 33

swine - tonsils and GI tracts

Question 34

How is Erysipelothrix rhusiopathiae spread?

Answer 34

ingestion of contaminated food or water, entry via skin wounds

Question 35

Where does Erysipelothrix rhusiopathiae normally persist?

Answer 35

organic matter in soil and water

Question 36

what are the virulence factors of Erysipelothrix rhusiopathiae?

Answer 36

Neuraminidase - adherence to endothelial cells Hyaluronidase - invasion of tissue capsule - survive and grow inside macrophages (facultative intracellular pathogens)

Question 37

what is the causative agent?

Answer 37

Erysipelothrix rhusiopathiae

Question 38

How does acute vs chronic Erysipelothrix rhusiopathiae present?

Answer 38

acute - severe septicemia, skin lesions, high mortality, abortion chronic - arthritis, endocarditis

Question 39

Veterinarians handling what animals are at risk for Erysipelothrix rhusiopathiae?

Answer 39

fish, poultry, swine, and agricultural industries

Question 40

How does Erysipelothrix rhusiopathiae present in humans?

Answer 40

localized cellulitis

Question 41

How is Erysipelothrix rhusiopathiae diagnosed

Answer 41

presumptive - clinical findings, gram + short to filamentous rods in tissue smears definitive - culture and ID bacterium

Question 42

what is another animal besides swine that can be affected by Erysipelothrix rhusiopathiae? what happens?

Answer 42

poultry (esp turkeys) - acute septicemia with sudden death