Lecture 9

Question 1

Where are Corynebacterium & Rhodococcus normally found?

Answer 1

Normal component of the microbiota -skin, mucous membranes, intestinal tract

Question 2

How does Corynebacterium & Rhodococcus do in the envr?

Answer 2

Found to survive up to 55 days in the envr

Question 3

What is the biocontainment level for Corynebacterium & Rhodococcus?

Answer 3

2

Question 4

Are Corynebacterium & Rhodococcus gram positive or negative?

Answer 4

Positive

Question 5

Describe the metabolism of Corynebacterium & Rhodococcus

Answer 5

Aerobic & facultative anaerobes

Question 6

What are the virulence factors for Corynebacterium renale?

Answer 6

Pilli (attachment)

Urease (production of ammonia)

Question 7

What are the virulence factors for Corynebacterium cystitidis?

Answer 7

Pilli (attachment)

Urease (production of ammonia)

Question 8

What are the virulence factors for Corynebacterium pilosum?

Answer 8

Pilli (attachment)

Urease (production of ammonia)

Question 9

What is the virulence factor for Corynebacterium pseudo tuberculosis?

Answer 9

Phospholipase D -inhibition of neutrophils & inactivation of complement
Vasodilatory factors –> enables it to go through lymphatic sys to reach lymph nodes & replicate

Question 10

What is the virulence factor for Rhodococcus equi?

Answer 10

VapA PRO - interferes with phagolysosome formation

Question 11

What is the virulence factor for Corynebacterium diphtheria?

Answer 11

Diphtheria toxin - cytotoxin acting by inhibiting PRO syn

Question 12

What disease does Corynebacterium pseudotuberculosis cause?

Answer 12

Caseous lymphadenitis in sheep & goats

Presence of pyogranulomatous abscesses of the lymph nodes & internal organs

Question 13

What is the prognosis of caseous lymphadenitis?

Answer 13

Highly contagious & persists in the envr –> once in the herd, it is difficult to eradicate

A/bs don’t penetrate well into highly encapsulated abscesses

Question 14

What disease does Corynebacterium renale cause in cattle?

Answer 14

Infections in the urinary tract (cystitis) & Pyelonephritis (infection of kidney)

Question 15

What is the prognosis of Corynebacterium renale in cattle?

Answer 15

Difficult to eradicate from infected herds

Tx success decres with disease progression

More difficult to eradicate from kidney

Px worsens with increasing renal damage

Question 16

How is Corynebacterium renale spread in cattle?

Answer 16

Maintained in herd by subclinical carriers & diseases animals

Transmission from animal to animal occurs by urine splashing onto the vulva of a susceptible cow

Question 17

How do you tx Corynebacterium renale infections?

Answer 17

Penicillin (goes through to the urine)

Question 18

What disease does Corynebacterium renale cause in sheep?

Answer 18

Balanoposthitis (pizzle rot) - inflammation of the penis & prepuce

Question 19

What is the pathogenesis of Balanoposthitis?

Answer 19

Diets too high in PRO increase urea [ ] in urine

Urea is converted into ammonia by the organism

Ammonia irritates the penis

Inflammation & ulceration occurs

Bacteria enter compromised tissues & cause infection

Scarring of the prepuce prevents penile extrusion & therefore, effects breeding

Question 20

How do you tx Balanoposthitis?

Answer 20

Combo of a/bs (definitely use penicillin)

Remove dead tissue & excess wool

Do not breed ram before healed, possible transmission

Question 21

What disease does Corynebacterium auriscanis cause?

Answer 21

Skin infections in dogs & cats but uk if it is an opportunistic pathogen or pathogen in the wound itself

Question 22

How do you tx Corynebacterium auriscanis infections in dogs & cats?

Answer 22

Tx may be challenging, need drugs to target all pathogens present

Question 23

What disease does Corynebacterium urealyticum cause?

Answer 23

Rare cause of UTIs in dogs & cats

Question 24

What does Corynebacterium diphtheriae cause in humans?

Answer 24

This is reported in animals, but more common in humans

Characteristic formation of diptheritic pseudo membrane over pharynx

Question 25

What disease does Rhodococcus equi cause in horses?

Answer 25

Severe bronchopneumonia in young foals & abscessation in older horses

Question 26

What are the symptoms of Rhodococcus equi infection in foals?

Answer 26

Typically present with pneumonia first See wt loss, diarrhea & colic In 50% of foals with pneumonia, there is enteric disease See multi-focal ulcerative enterocolitis & typhlitis

Question 27

How do horses get Rhodococcus equi infections?

Answer 27

Organism is acquired from the envr Found in soils, particularly those contaminated with horse feces Only strains containing VapA are virulent in horses, become infected by inhaling the strain

Question 28

What is the prognosis of Rhodococcus equi in horses?

Answer 28

Fair in foals with chronic disease Poor in foals with acute disease

Question 29

What is the tx for Rhodococcus equi in horses?

Answer 29

A/bs Rifampin+ macrolide type drug Envr clean - manure, avoid overcrowding, reduce dust, provide ventilation

Question 30

What disease does Rhodococcus equi cause in cats?

Answer 30

Rarely reported but increase Most often cause cutaneous infections in immunocompromised animals Lesions are characterized as pyogranulomatous inflammation (typically not painful) Abscesses & lesions on parenchymal organs also reported

Question 31

What is the tx for Rhodococcus equi in cats?

Answer 31

Surgical drainage of abscesses & a/bs

Question 32

How do you collect C. pseudotuberculosis samples?

Answer 32

pus or exudates

Question 33

How do you collect C. renale grp samples?

Answer 33

Mid-stream urine

Question 34

How do you collect R. equi samples?

Answer 34

Trans-tracheal wash

Question 35

How should the samples be handled for Corynebacterium & Rhodococcus app be handled?

Answer 35

Send swabs with transport media Do not freeze

Question 36

Is Corynebacterium pseudotuberculosis zoonotic?

Answer 36

Yes, can cause abscesses in humans (contamination during shearing)

Question 37

Is Corynebacterium renale zoonotic?

Answer 37

Yes, but low risk to humans

Question 38

Is Corynebacterium ulcerans zoonotic?

Answer 38

Yes, cutaneous diphtheria in people also isolated from animals

Question 39

Is Rhodococcus equi zoonotic?

Answer 39

Rare, primarily in immunocompromised patients

Question 40

What a/b is Corynebacterium app resistant to?

Answer 40

Fosfomycin

Question 41

How should you tx Rhodococcus generally?

Answer 41

MLSBK + rifampin (consider rifampin toxicity in small animals)