Rhodococcus

Question 1

Rhodococcus - Descriptive statment

Answer 1

Gram +, aerobic, pleomorphic coccobacillus (watermelon seeds), Facultative intracellular (macrophages). Catalase +, weakly acid fast, non hemolytic, Mucoid (salmon pink colonies on blood agar) CAMP + with Staph aureus.

Question 2

Rhodococcus Pathogenesis

Answer 2

C3b Opsonization –> macrophage phagocytosis–> escapes/survives inside phagolysosome (Vaps, cell wall) –> Down regulates IFN-g –> Sub acute to chronic inflammation

Question 3

Rhodococcus Virulence factors

Answer 3

VAPs- intracellular survival

Question 4

Rhodococcus equi in foals

Answer 4

Summer (heat & dust) - Inhalation transmission - pyogranulomatous bronchopneumonia - Ulcerative colitis & mesenteric lymphadenitis - Osteomyelitis (if bacteremia)

Question 5

Summertime, pyogranulomatous bronchopneumonia, ulcerative colitis & mesenteric lymphadenitis, possible osteomyelitis

Answer 5

Rhodococcus equi in foals

Question 6

Rhodococcus in swine

Answer 6

Mild cervical lymphadenitis (tuberculosis-like lesions)

Question 7

Rhodococcus in Crocodiles/ american alligators

Answer 7

Rare - pyogranulomatous pneumonia - hepatic abscesses - lymphadenitis (lungs, liver, lymph)

Question 8

When I say pyogranulomatous pneumonia, you say….

Answer 8

Rhodococcus equi!

Question 9

Case Study - Late term abortion of a thouroughbred, first reported case of placentitis in a horse

Answer 9

Rhodococcus equi infection in a thoroughbred