Lecture 12 & 13

Question 1

What is the biocontainment level for Erysipelothrix?

Answer 1

2

Question 2

Does Erysipelothrix form spores?

Answer 2

NO

Question 3

Is Erysipelothrix gram positive or negative?

Answer 3

positive

Question 4

Describe the appearance of Erysipelothrix

Answer 4

Slender, non-branching rods or chains of rods

Irregular morphology (curved)

Question 5

Describe the metabolism of Erysipelothrix (3)

Answer 5

Facultative anaerobic

gamma hemolytic or weekly alpha hemolytic on blood agar

Catalase negative

Question 6

Where is Erysipelothrix found?

Answer 6

Wide range of spp - mammals, birds, reptiles, fish, shellfish, crustaceans & wild ungulates

Shed in faces of pigs

Persists in envr

Question 7

What are the virulence factors of Erysipelothrix? (3)

Answer 7

Capsule - provides resistance to phagocytosis & allows organism to survive in the oxidative burst within macrophages

Neuraminidase - promotes attachment & aids in invasion of mucosal surfaces & vasculature

SpaA PRO - surface PRO that aids in attachment

Question 8

What virulence factor of Erysipelothrix is responsible for generating cell-mediated immunity rather than humoral? Is this protective?

Answer 8

SpA PRO

Yes, antibodies are protective

Question 9

What disease does Erysipelothrix rhusiopathiae cause in pigs?

Answer 9

Swine Erysipelas

Question 10

What is the pathogenesis of Swine Erysipelas caused by Erysipelothrix rhusiopathiae?

Answer 10

Affects pigs older than 3 mo due to waning material immunity

Fecal-oral exposure

Enters body through palatine tonsils followed by systemic spread (bacteremia)

In acute case, it can lead to DIC & thrombi. Thrombi get lodged in capillaries & venues –> ischemic necrosis & lesions

Question 11

What are the symptoms of Acute Swine Erysipelas caused by Erysipelothrix rhusiopathiae? (6)

Answer 11

Sudden onset

Pyrexia & sometimes death

Depression

Inappetence

Diamond skin lesions 2-3 days after exposure (if severe, the diamond lesions won’t occur before death)

Question 12

What are the symptoms of Subacute Swine Erysipelas caused by Erysipelothrix rhusiopathiae?

Answer 12

Disease is less severe than acute

Question 13

What are the symptoms of Chronic Swine Erysipelas caused by Erysipelothrix rhusiopathiae? (3)

Answer 13

Long term sequelae following acute disease

Arthritis & stiffness - thrombi can become lodged in joints

Poss cardiac insufficiency if damage to heart valves during acute phase

Question 14

What are the symptoms of Erysipelothrix rhusiopathiae in turkeys? (4)

Answer 14

Begins with death of several birds & others which are droopy

Toms may have congested, purple snoods

Death is per-acute

Endocarditis is usually the cause in turkeys that died

Question 15

Describe the pattern of disease of Erysipelothrix rhusiopathiae in wild ungulates

Answer 15

Large die-offs

Mortality due to this organism is new

Poss effecting naive pop

Question 16

Is Erysipelothrix rhusiopathiae zoonotic?

Answer 16

To those with exposure risk - vets, butchers & fish handlers

Presents as skin lesions & can lead to L sided endocarditis

Question 17

What disease does Erysipelothrix tonsillarum cause in dogs?

Answer 17

Endocarditis

Question 18

What are the symptoms of Erysipelothrix tonsillarum in dogs? (2)

Answer 18

Fever

Recent onset of murmur

Question 19

How do you tx Erysipelothrix tonsillarum in dogs?

Answer 19

Penicillin

Extended tx length required

Question 20

What disease does Erysipelothrix spp cause in ornamental fish?

Answer 20

Death

Question 21

What are the clinical signs of Erysipelothrix in ornamental fish?

Answer 21

Lethargy

Hovering in the water

Hemorrhage of fins & skin

Question 22

What do samples do you collect for Erysipelothrix?

Answer 22

Necropsy - liver, spleen, kidney, heart, synovial tissue, long bone samples

Blood cultures

Difficult to collect skin samples

Question 23

How do you handle samples for Erysipelothrix spp?

Answer 23

DO NOT FREEZE

Question 24

How does the lab test for Erysipelothrix?

Answer 24

Blood agar

Selective media - including agar containing a/bs

MALDI-TOF

Question 25

How do you tx for Erysipelothrix spp?

Answer 25

Penicillin Pathology may complicate

Question 26

What tx do you avoid for Erysipelothrix? (3)

Answer 26

Sulfonamides Aminoglycosides GLycopeptides (vancomycin)

Question 27

What is the containment level for B. anthracis?

Answer 27

3

Question 28

What is the biocontainment level for B. cereus?

Answer 28

2

Question 29

What is the biocontainment level for B. subtitles?

Answer 29

1

Question 30

Describe the appearance of Bacillus (4)

Answer 30

Large Spore forming Gram positive Rods

Question 31

Describe the metabolism of Bacillus

Answer 31

Facultative anaerobe

Question 32

Describe the appearance of Bacillus on a plate (2)

Answer 32

Large, irregular colonies

Question 33

Describe the appearance of Bacillus anthracis on a plate (2)

Answer 33

grey Non-hemolytic colonies

Question 34

What spp have the Medusa heads on a gram stain?

Answer 34

Bacillus anthracis

Question 35

Where is Bacillus found?

Answer 35

Envr - water & soil Spores survive for decades - highly resistant

Question 36

What are the virulence factors for Bacillus anthracis? (3)

Answer 36

Protective antigen- forms heptameric pores in cell walls (within host cells) THEN, an edema factor or lethal factor will bind to create toxins Lethal toxin - affects macrophages inhibiting macromolecular syn & stimulates apoptosis Edema toxin - results in increase cAMP levels intracell & effects H2O homeostasis (FYI- these 3 PROs are inactive on their own, need to come together to be activated)

Question 37

Describe the virulence process of Bacillus anthracis

Answer 37

Capsule forms around the vegetative cells & other factors for a PRO Protective antigen binds to host cells They aggregate together to form a heptamer Edema or lethal factor bind to the heptamer resulting in endocytosis of the entire complex Complex spans the entire cell membrane allowing both factors to be cleaved & enter the cytoplasm of the cell to exert their toxic effects

Question 38

What is the virulence factor for Bacillus cereus ?

Answer 38

Exotoxins responsible for gastroenteritis

Question 39

What is the virulence factor for Bacillus thuringiensis?

Answer 39

Crystal toxins - digestion of crystal liberates Cry toxin & disrupts the gut Used as larvicide in mosquito control

Question 40

What is the virulence factor for Bacillus subtilis?

Answer 40

Non-pathogenic

Question 41

Describe the process of the motility test

Answer 41

Put swab in the media straight down the middle (use needle or straight wire) If it diffuses outwards from the stab line then it is positive & if it only stays in the stab line then it is negative

Question 42

Diff spp have diff susceptibility to Bacillus anthracis, why might that be? What spp have the most, intermediate & lowest susceptibility to disease?

Answer 42

Due to the envr that the spp resides If they are in an envr with high exposure to soil then they have more exposure to spores then they are very suscpetible - includes cattle, sheep & goats (most susceptible) For those spp with moderate exposure to soil & spores they have intermediate susceptibility - horses & humans For spp which only are exposed to soil when scavenging they have the lowest susceptibility - pigs, birds & carnivores

Question 43

How do ruminants acquire Bacillus anthracis?

Answer 43

Ingestion of an endospore Often seen when there is a drought followed by heavy rainfall

Question 44

What is the outcome if a ruminant is exposed to Bacillus anthracis?

Answer 44

Sudden death Peracute disease

Question 45

What are some signs during a necropsy that the animal has been infected by Bacillus anthracis?

Answer 45

Failure to clot Incomplete rigor mortis Splenomegaly - if you cut into a carcass & blood flows freely

Question 46

Why should you never perform a necropsy if you suspect Bacillus anthracis?

Answer 46

B/c if the organisms are exposed to O2 they sporulate & since they are extremely resistant spores it will be very difficult to rid them of the envr If you see splenomegaly, STOP cutting Call CFIA if you suspect

Question 47

How does Bacillus anthracis present in horses?

Answer 47

Acute intestinal disease - colic, diarrhea, fever & depression Localized lesions can be seen May see dependent edema = thorax, abdomen, prepuce, mammary gland Followed by fatal septicaemia

Question 48

How do horses become exposed to Bacillus anthracis?

Answer 48

Thought to be due to insect transmission

Question 49

What are the 4 forms of Bacillus anthracis in humans?

Answer 49

Cutaneous - most common Pulmonary - inhale spores Oropharyngeal - ingest spores Gastrointestinal - ingest spores

Question 50

How do you collect a sample for Bacillus anthracis?

Answer 50

Call CFIA Do not perform necropsy Collect blood from ear If you are working in a dusty envr, use protection

Question 51

How do you handle Bacillus anthracis samples?

Answer 51

DO NOT FREEZE

Question 52

How does the lab diagnose Bacillus anthracis?

Answer 52

Direct microscopy - look for encapsulated organisms from tissues

Question 53

How does the lab dx non-anthracis bacillus spp?

Answer 53

Culture

Question 54

How do you get rid of Bacillus anthracis from the envr? (3)

Answer 54

Very difficult to get rid of Remove top 20cm of soil Disinfect soil & equipment with formalin Burn or bury contaminated disposables along with carcasses

Question 55

How do you tx Bacillus anthracis? (6)

Answer 55

High dose of penicillins or tetracyclines Vacc is available Antimicrobial prophylaxis may be appropriate in some outbreak situations Control area - keep animals out Proper disposal of carcasses Prevent additional contamination of the envr