Rhodococcus

Question 1

What color is rhodococcus?

Answer 1

Red colored- after 24 hours produce pink colonies in the agar

Question 2

Who are the main host for this bacteria?

Answer 2

Horses- Especially foals 1-6 months old

Question 3

mainly associated with what types of lesions?

Answer 3

granulose and pyogranulous

Question 4

What kind of cell wall does this bacteria have?

Answer 4

very Lipid rich!

Question 5

Is rhodococcus acid fast positive or negative?

Answer 5

Acid fast positive- rich in mycolic acid

Question 6

Rhodococcus is a facultative _____ organism

Answer 6

intracellular

Question 7

What cells do Rhodococcus live in?

Answer 7

Macrophages- develop granulomas

Question 8

What kind of immune response do we want for Rhodococcus?

Answer 8

cell mediated immune response- Th1

Question 9

Is rhodococcus aerobic or anaerobic?

Answer 9

Aerobic

Question 10

Rhodococcus is: catalase _____ oxidase ______ CAMP ______

Answer 10

positive, negative, positive

Question 11

True or False: Rhodococcus is spore forming and non motile

Answer 11

FALSE- non- spore forming and non motile

Question 12

Rhodococcus are gram positive ____

Answer 12

bacilli- (very small and can look like cocci) also can be pleomorphic with rods and cocci

Question 13

Does Rhodococcus have a capsule?

Answer 13

Yes, they are encapsulated

Question 14

Picture of Gram stain for Rhodococcus

Answer 14

Pleomorphic gram stain

Question 15

Would Rhodococcus be positive or negative on the Ziehl-Neelsen stain?

Answer 15

positive, because this is the acid fast stain

Question 16

What is the only pathogenic species of Rhodococcus?

Answer 16

Rhodococcus Equi

Question 17

What does rhodococcus equi cause in foals?

Answer 17

pneumonia

Question 18

The antibiotic that you use needs to ____ the cell

Answer 18

penetrate

Question 19

What are the virulence factors of Rhodococcus?

Answer 19

Capsule, cell wall, and Vaps

Question 20

Why does Rhodococcus want C3b to bind to them?

Answer 20

They want to be opsonized so that the macrophages will take them in. Once inside the macrophage, they will replicate

Question 21

Does Rhodococcus want to be uptaken by the FC receptor?

Answer 21

no- they will get killed via this pathway

Question 22

Is the capsule anti-phagocytic?

Answer 22

not in Rhodococcus! They want to be taken up by the macrophages

Question 23

What are Vaps?

Answer 23

virulence associated proteins

Question 24

Rhodococcus equi that has lost its plasmid and do not produce Vaps are ____ in virulence

Answer 24

lower

Question 25

\_\_\_\_\_\_ have genes that will code for the virulence associated proteins

Answer 25

Pathogenicity islands

Question 26

What is the role of pathogenicity islands?

Answer 26

1. intracellular survival 2. down regulation of IFN gamma 3. Temperature regulation

Question 27

Why does Rhodococcus down regulate IFN gamma?

Answer 27

IFN gamma is one of the key cytokines necessary for Th1 activation of the cell mediated immunity

Question 28

Does Rhodococcus survive in the environment for long periods of time?

Answer 28

YES- it can persist in dry environments

Question 29

What environment does Rhodococcus persist in?

Answer 29

Soil and animal manure

Question 30

Does Rhodococcus have high variability?

Answer 30

yes!- many different antigens present in the capsules

Question 31

How is Rhodococcus transmitted?

Answer 31

inhalation, ingestion or congenitally

Question 32

Pathogenesis of Rhodococcus

Answer 32

1. Opsonization by C3b and will be taken in by macrophages 2. Induces Vaps and survives inside the phagolysosome 3. Down regulates IFN gamma 4. Causes pyogranulomatose to granulomatose lesions

Question 33

What will the prognosis of foals depend on?

Answer 33

The passive immunity and the amount of maternal anitbodies in the foal. Also, if the bacteria have the plasmid that encode for the pathogenicity island then the Vaps will be more virulent

Question 34

What are the elements of the granulomatous inflammation?

Answer 34

macrophages, giant cells and neutrophils

Question 35

What is the main manifestation in Foals?

Answer 35

Pneumonia- produces large abscesses in the lungs and lymph nodes

Question 36

What happens if Rhodococcus is swallowed and gets into the GI tract?

Answer 36

Ulcerative intestinal lesions

Question 37

What is the fatality rate in foals?

Answer 37

50%

Question 38

Rhodococcus equi causes what in the lungs?

Answer 38

Pyogranulomatous Bronchopneumonia

Question 39

What does Rhodococcus equi cause in the GI tract?

Answer 39

enteritis

Question 40

Does Rhodococcus affect Humans?

Answer 40

It can cause pneumonia in immunocompromised individuals. Mortality can reach 50%

Question 41

What does Rhodococcus cause in swine?

Answer 41

Nasty lesions of the lymph node

Question 42

When is the seasonal peak for Rhodococcus?

Answer 42

Summer- heat and dust

Question 43

What kind of immunity do you want?

Answer 43

Both cell mediated and Humoral immunity, however cell mediated is much more important. Antibodies for the foals are extremely important

Question 44

Is there a vaccine for Rhodococcus?

Answer 44

No

Question 45

What will you see in stains of infected tissue?

Answer 45

Intracellular and extracellular clusters of Gram positive cocci or rods. Completely packed macrophages

Question 46

What will the media show with Rhodococcus growth?

Answer 46

non hemolytic mucoid colonies

Question 47

This bacteria has a positive CAMP test with \_\_\_\_\_

Answer 47

Staph aureus or C. pseudotuberculosis- when cultured with these bacteria it produces complete hemolysis

Question 48

What is the treatment?

Answer 48

Sick foal should be isolated and treated with antimicrobials (drug needs to penetrate the macrophages). PREVENTION is key - good colostrum is very important - dust control

Question 49

Do foals have a good or bad prognosis?

Answer 49

Bad