Listeria & Erysipelothrix Flashcards
What kind of bacteria are Listeria?
Small, Gram +, coccobacilli-rods
What are the key points about Listeria?
Ubiquitous in the environment
Carried in a wide variety of animals as asymptomatic enteric carriers
Poor silage and food items are common source of outbreaks
What is the clinical significance of Listeria monocytogenes?
Winter/spring disease of feedlot our housed ruminants
Outbreaks due to poor quality silage
Economically important disease with seasonal occurrence (winer months)
Ingestion/inhalation or enter via minute wounds in buccal mucosa
Where does L. monocytogenes localize?
Localize in brain stem, intestinal wall, and placenta
What does L. monocytogenes cause?
Septicemia, abortion, and encephalitis
What are the two forms of Listeriosis?
- Visceral
2. Neural (predominantly in ruminants)
What is the pathogenesis of L. monocytogenes?
Invasive / Enters blood stream
Facultative intracellular bacteria: persist in macrophages
Intracellular growth
What are the virulence factors of L. monocytogenes?
Internalin
Listeriolysin (hemolysin)
Act A
What is the most common disease presentation in ruminants for L. monocytogenes?
Encephalitis: Have an affinity for brainstem
What is the common disease presentation in monogastric and newborn animals for L. monocytogenes?
Septicemia
The abortion the L. monocytogenes causes can result in what?
Focal hepatic necrosis
What are the neurologic symptoms in ruminants for L. monocytogenes?
Dullness, turning or twisting, walking in circles
Unilateral trigeminal and facial paralysis
What are the lesions in ruminants for L. monocytogenes?
Prominent lesions in brain stem
Microabscesses and glial nodules
Meningitis
Acute vascular fibroid necrosis
Neuronal necrosis, neuritis and perineuritis of cranial nerves
In cases of septicemia, how would you DX L. monocytogenes?
Culture liver and spleen
Would you treat CNS disease in ruminants for L. monocytogenes?
Not usually
What are the drugs that L. monocytogenes is susceptible to?
Penecillin, ceftiofur, tetracycline, erythromycin, and trimethoprim/sulfonamid
What is a good drug combo to treatment of L. monocytogenes?
Ampicillin and Gentamicin
How would you prevent L. monocytogenes in ruminants?
Avoid feeding poor quality silage
What kind of bacteria are Erysipelothrix?
Small, aerobic, Gram + rods
What is the most important reservoir for Erysipelothrix rhusiopathiae?
Swine
What four syndromes are observed in swine with E. rhusiopathiae?
- Septicemia
- Dermatopathy
- Arthritis
- Endocarditis
How is E. rhusiopathiae primarily transmitted?
Orally
What is a virulence factor of E. rhusiopathiae?
Neuraminidase: leads to vascular damage and hyaline thrombus formation
What is the disease that E. rhusiopathiae causes in swine?
Skin erysipelas or Diamond skin disease
