Gram positives week 5

Question 1

Listeria characteristics

Answer 1

coccobacillary rods, facultative anaerobes, have flagella at 25 degrees.
Catalase pos, oxidase neg.
survive in pH 5.5-9.6
Psychrophilic - can grow in the fridge
Ubiquitous in the environment, normal in mammalian GIT. Resistant to harsh environmental conditions.

Question 2

3 main clinical symptoms of Listeriosis

Answer 2

Encephalitis, septicemia, abortion

Question 3

InlA and InlB pathogenic effect

Answer 3

adhesion. A attaches to enterocytes, B to hepatocytes

Question 4

Disease name for listeriosis

Answer 4

circling disease, silage disease

Question 5

Listeriosis in ruminants

Answer 5

encephalitis most common symptom. Affects all ages and both sexes, seasonal occurrence. Often due to spoiled silage. Can enter through ingestion, inhalation, or via breaks in oral/nasal mucosa

Question 6

Listeriosis CS

Answer 6

anorexia, depression, twisting head to one side, walking in circles toward affected side, unilateral CNV and CNVII paralysis

Question 7

Diagnosis of Listeriosis

Answer 7

history, symptoms, season, silage quality, specific lesions of the brain (microabscesses infiltrated by neutrophils/macrophages containing bact, meningitis, perivascular cuffing, neuronal necrosis). Culture brainstem tissue.
Septicemia - culture liver, spleen and blood
abortion - foetal abomasal content and uterine discharges

Question 8

Listeriosis Tx and prevention

Answer 8

systemic therapy with antibiotics - septic listeriosis
neural listeriosis - poor response to anti-b’s
Prevention is key - check your silage, stop feeding if outbreak occurs

Question 9

Erysipelothrix general characteristics

Answer 9

small rods usually in colony form, facultative anaerobes, non motile, catale and oxidase neg, found in tonsils of many species and slime layer of fish.
Up to 50% of healthy pigs have in their tonsils, carrier pigs excrete it in feces and oronasal secretions. Resistant to harsh environmental conditions
Transmission = ingestion

Question 10

four erysipelothrix syndromes observed in pigs

Answer 10

septicemia, dermatopathy, arthritis, endocarditis

Question 11

Listeriolysin O (LLO)

Answer 11

pore-forming cytolytic toxin – destroys membranes of phagosome

Question 12

ActA protein (listeria)

Answer 12

actin-polymerizing protein

Question 13

phospholipase C enzymes (PLC) - listeria

Answer 13

degradation of cytoplasmic and endocytic membranes

Question 14

Neuraminidase (erysipelothrix)

Answer 14

cleaves sialic acid on endothelial cell surfaces, leads to hyaline thrombus formation.
important for adherence and invasion of endothelial cells

Question 15

polysaccharide capsule

Answer 15

protection against phagocytosis and allows intracellular replication

Question 16

hyaluronidase

Answer 16

dissemination of bacteria within tissues

Question 17

spaA surface protein

Answer 17

adhesion

Question 18

Swine erysipelas (diamond skin disease)

Answer 18

Acute form: sudden death, fever, stiff gait, skin lesions
subacute form: inappetance, fever, skin lesions
chronic form: arthritis, heart problems, endocarditis, polyarthritis, skin lesions
*diamond lesions pathognomonic

Question 19

swine erysipelas susceptible groups

Answer 19

pigs 3 months - 1 year, stressed pigs may trigger disease

Question 20

Swine erysipelas diagnosis

Answer 20

based on skin lesions, isolation of bacteria or PCR-based methods

Question 21

Swine erysipelas treatment and control

Answer 21

Tx: acute form - isolate and treat with antimicrobials. Cull chronically affected animals
Control: good hygiene, vaccination before entering the breeding herd. Boars every 6 months, sows 3-4 week pre-farrowing

Question 22

Erysipelas in turkeys

Answer 22

acute form: septicemia, sudden death

chronic form: endocarditis and weight loss

Question 23

Non-suppurative polyarthritis

Answer 23

in lambs
organisms enter through umbilicus or castration wounds. post-dipping lameness due to cellulitis and laminitis in older lambs

Question 24

Erysipeloid zoonosis

Answer 24

occupational hazard (vets, fish/pig industries). Enters through minor skin abrasions and causes cellulitis in fingers, diffuse skin infections, septicemia.