Clostridium - made a table instead Flashcards
what is the causative agent of botulism?
Clostridium botulinum
where are the endospores of botulism found?
distributed in soils and aquatic environments
what are the 7 types of toxins of C. botulinum?
A, B, C, D, E, F, & G
When choosing an antitoxin for botulism what is most important for it to be an effective treatment?
antitoxin must match toxin
what type of paralysis is seen with C. botulinum?
flaccid paralysis
Describe the botulism endospores
oval subterminal endospores, bulge mother cells
what is the most common toxin in cattle and what part of the cow contains the toxin?
bones and meat contain BoNT
what is shaker foal syndrome?
in horses from type b
foal found dead or progressive symmetric motor paralysis
How does the botulinum neurotoxin cause disease?
enter cystosol of host cell and cleaves SNARE proteins required for membrane fusion of synaptic vesicles and cell membrane > blocks AcH release
what are clinical manifestations of C. botulinum?
tongue, jaw, and tail flaccidity
incoordination and knuckling fetlocks
flaccid paralysis
How is botulism diagnosed?
eliminate other possible causes
history, clinicals signs, ID of toxin in serum/tissue before death
why is the toxin not useful in dead carcaccases?
environmental organism used to deregulate dead carcasses > false positive
why are you likely unable to culture C. botulinum from non-toxicoinfection cases?
cant grow in gut well
toxin is what is important for disease not the bacteria
what does PCR detect for botulism?
toxin genes
requires bacteria from culture or patient
How is C. botulinum treated and controlled?
evacuation of stomach and purging for recent ingestion
polyvalent antiserum - binds unbound toxin, serotype specific
what diseases does C. chauvoei cause?
blackleg
clostridial myositis
black quarter
what hemolysis does C. chauveoi have?
B hemolysis
where is C. chauveio found?
naturally in intestinal tract of animals
How does C. chauveio enter tissues?
likely ingested, organism crosses epithelial layer in GI tract to enter tissues
Is C. chauveio an endogenous or exogenous disease?
endogenous disease - disease may occur without a wound
what is the virulence factor for C. chauveio? what does it do?
CctA : Clostridium chauvoei toxin A > perforates host cell membrane
What age of cattle is blackleg most commonly found?
well-fed 6m-2yr most commonly
How is blackleg cause in sheep?
C. chauvoei-associated gas gangrene
wound infections > follows injury
What generates lesions in blackleg? Describe lesions
CctA
dry, dark, emphysematous
what are the clinical manifestations of blackleg?
gangrenous cellulitis & crepitant myositis
acute development lameness, edema, crepitation
How is blackleg diagnosed?
How is blackleg treated?
vaccinate susceptible animals and treat prophylactically with penicillin for up to 14 days
How is blackleg controlled?
vaccination - Bacterin (killed bacteria) vaccine produced with local, previously identified clostridial strains of C. chauvoei in cases where toxoid vaccine is ineffective
what is the causative agent of infectious necrotic hepatitis (black disease)?
C. novyi
Where is C. novyi found?
worldwide soil borne organism
often present intestine and liver of herbivores
what is the key virulence factor for black disease?
TcnA - lethal, necrotizing, activates GTP binding proteins leading to edema
What species is C. novyi type B found?
sheep and cattle
How are sheep and catle infected with C. novyi Type B?
endospores ingested and migrate to Kupffer cells in liver where they remain dormant
How is the liver injured with C. novyi type B?
fluke migration - tissue is anoxic so endospores germinate
What clinic signs are seen with black disease?
rarely observed and cattle simply found dead
How is black disease diagnosed?
liver lesions - grayish yellow gross lesions - fluke tracts
contain large gram + rods in liver
Postmortem how does c. novyi contaminant liver?
GI tract
How is C. novyi type B controlled?
prophylactic vaccination w/ bacterin - toxoid combination
control fluke and other hepatopathic agents
How often do animals have to be vaccinated for C. novyi type B?
long term immunity - 1 vaccination
what is the causative agent of bacillary hemoglobniuria (red water disease)?
C. haemolyticum
what type of disease is red water disease?
acute, infectious toxemic disease
what species does red water disease infect? where?
ruminants - rocky mtn, pacific coast, gulf of mexico
How are ruminants infected with C. haemolyticum?
grazing in pastures infested with liver flukes encysted on vegetation
what is the virulence factor of C. haemolyticum?
B-toxin - hemolytic and necrotizing phospholipase C
How do liver flukes contribute to C. haemolyticum infection?
young liver flukes excyst in duodenum > burrow through intestinal wall then migrate to and enter liver > damage creates anaerobic tissue > C. haemolyticum can grow
what leads to hepatocyte necrosis and endovascular thrombosis with C. haemolyticum?
toxin production by vegetative growth
what are the clinical manifestations with a subacute infection of C. haemolyticum?
fever, jaundice, anorexia, abdominal pain, rapid deep breathing, decreased milk production, blood in feces and urine
How is red water disease diagnosed?
clinical history
necropsy - lesions (infarcts) in liver
How is C. hameolyticum confirmed?
C. haemolyticum in liver infarction
How is red water disease treated?
Antibiotic treatment likely ineffective
antitoxin
How is C. haemolyticum controlled?
vaccination
seasonal - 1 dose prior to dry season
constant protection - semiannual vaccination
