Bacti Final Exam Flashcards
(165 cards)
What are the characteristics of Clostridium? (gram positive or negative, aerobic or anaerobic, etc)
-Gram positive
-rods/bacillus (short rods)
-Anaerobic
-Spore forming (anaerobic transmission)
-Toxin producing
Which clostridium species are histotoxic and which are neurotoxic?
-Histotoxic: C. perfringens (also enterotoxic), C. chauvoei, C. haemolyticum, C. novyi. C. septicum
-Neurotoxic: C. botulinum, C. tetani
Which species of Clostridium is both enterotoxic and histotoxic?
C. perfringens
Which species of Clostridium is the fastest replicating bacteria?
C. perfringens
How are the different subtypes of C. perfringens identified?
The type of toxin it produces (toxinotype A-E)
What are the virulence factors for C. perfringens?
-Alpha toxin: hydrolyzes the cell membranes
-Perfringolysin O: binds to cholesterol and forms pores resulting in cell death
-Glycosidases and lipases
-Sialidase: removes sialic acid residues from host cells
-capsule
What condition does C. perfringens cause? What are the symptoms of this condition?
Gas gangrene: necrotizing cellulitis and myonecrosis, edema, hemorrhage, gas production, toxemia
What are the virulence factors for C. chauvoei?
-Alpha toxin: pore forming hemolysin
-Beta toxin: DNAase
-Sialidase: removes sialic acid causing tissue disruption
-Chauveolysin: similar to perfringen toxin, binds cholesterol and causes cell death
What disease does C. chauvoei cause in cattle? Describe what the associated lesions look like.
Blackleg: muscles have a dark, emphysematous center with hemorrhage and edema around the outside
What are the symptoms of Blackleg?
High fever, lameness, anorexia, visible swelling of affected muscles, affected muscle will have rancid butter odor, sudden death
Where does C. chauvoei reside? How does it get there?
Resides in intestine, liver, and other tissues
Ingestion of contaminated feces and then spores travel to liver and other tissues or the bacteria enters externally through a wound (need germination of spores for disease to occur)
Describe the pathogenesis of C. chauvoei.
Spores in muscles -> decreased the O2 levels -> anoxia causes bruising and gadding of young cattle (exercise intolerance) germination -> toxin production
How can you diagnose a C. chauvoei infection?
-Fecal smear and gram stain
-PCR
-Culture at 37C
How do you treat a C. chauvoei infection? Is there a vaccine available?
-There is a vaccine
-Tx is usually unsuccessful, IV penicillin followed by IM
What is the main virulence factor of C. haemolyticum?
Phospholipase C
What disease does C. haemolyticum cause in ruminants? What are the symptoms?
-Redwater disease
-Clinical signs: hemoglobinuria, fever, pale/icteric MM, abortion, agalactia
Describe the pathogenesis of a C. haemolyticium infection.
Ingestion of spores -> travel to liver -> spore germination in liver -> vegetation growth and production of phospholipase C -> hemolytic crisis and rapid death
How do you treat a C. haemolytcum infection? Is there a vaccine available?
-Vaccine available in endemic areas
-Treat with broad spectrum abx such as tetracycline and blood transfusion if needed
What are the virulence factors of C. noyvi?
-Alpha toxin: breaks down cytoskeleton
-Beta and delta toxins: cell membrane damage
What disease does C. noyvi cause in rams? Describe its pathogenesis
-Bighead
-Fighting injury -> activation of spores -> edema in head and neck -> death
What disease does C. noyvi cause in ruminants?
Pseudoblackleg: spores get to liver causing hemolytic crisis and death
How do you diagnose a C. noyvi infection?
Gram stain liver lesions: large gram positive rods with spores at the ends
How do you treat a C. noyvi infection? Is there a vaccine available?
-Toxoid vaccine is effective
-No effective treatment
What condition is caused by C. botulinum? What is the main clinical sign?
Botulism, flaccid paralysis