5.4 Gram Positive Anaerobic Rods Flashcards
clostridium is widespread in __________ and commensal of the _____________
in the soil; large bowel
clostridium multiplies slow/rapid
rapid
T/F clostridium is spore-forming
T
what is a key virulence factor of clostridium spp.
spore forming and produce powerful toxins
what are the 3 types of pathogenic clostridia
enterotoxin; histotoxic; neurotoxic
what spp of clostridia are enterotoxic
C. perfringens type A-E; C. difficile
what spp. of clostridia are neurotoxic
C. tetani and C. botulinum
what spp. of clostridia are histotoxic
C. chauvoei, C. septicum, C. novyi, C. sordelli, C. perfringens type A
describe enterotoxic vs neurotoxic vs histotoxic clostridia
enterotoxic: toxins are produced in the intestines, absorbed into the blood and then cause toxemia
histotoxic: gas-gangrene producing, invasive
neurotoxic: non-invasive and colonize the nervous system
T/F C. perfringens is zoonotic and reportable
F
what is the fastest growing bacterium known
C. perfringens
what type of contamination is C. perfringens associated with
fecal contamination
how many types of toxins does C. perfringens produce
7 (A-G)
what type of C. perfringens is associated with lamb dysentry? what is the toxin?
C. perfringens type B; Beta and epsilon
what type of C. perfringens is commensal? what is the toxin?
Type A; alpha
describe C. perfringens Type C, E and G; what toxins; what species
Type C: haemorrhagic necrotic enteritis; toxin = beta; all food animals
Type E: haemorrhagic enteritis, toxin = iota; cattle, sheep
Type G: necrotic enteritis; toxin = NetB; poultry
what type of C. perfringens is associated with foodborne illness in humans? what is the toxin?
Type F; Cpe
what type of C. perfringens is associated with pulpy kidney? what species? what toxin?
Type D; epsilon; sheep and goats
what two diseases can be caused by C. perfringens Type A and why does this happen if Type A is usually commensal?
1) abomasitis (calves)
2) haemorrhagic necrotic enteritis (dogs and foals)
Happens when the Type A bacteria produces a toxin other than the alpha toxin
what type of C. perfringens is NOT associated with enteritis? what DOES is cause (2)?
pulpy kidney disease (Type D); encephalomalacia and damage to kidneys
Type F (Cpe, food poisoning) C. perfringens is associated with ______-rich food consumption by people
protein
what type of C. perfringens is both enterotoxic and histotoxic? when histotoxic, what does it cause
Type A; gas gangrene (wound infections) and necrotizing mastitis
why is gas gangrene or necrotizing mastitis caused by C. perfringens Type A easy to diagnose
because it should NEVER be isolated anywhere except for the large bowel, where it is normally commensal
how do we control C. perfringens (3)
- prophylaxis (broilers)
- vaccination (pulpy kidney)
- hygeine (mastitis/gangrene)
how do we treat C. perfringens
debriding (if wound) and antibiotics
T/F C. difficile is zoonotic and reportable
F; zoonotic but not reportable
what is the main disease caused by C. difficile and in what species
typhlocolitis in horses
how does C. difficile develop
antibiotics disrupt the normal flora, but C. diff survives as a spore; C. diff can then proliferate and cause typhlocolitis a few days after starting or terminating antibiotics
how is C. difficile transmitted and activated
via spores, which are activated by the stomach and bile acids
what toxins does C. difficile produce (2)
Toxin A: enterotoxin and cytotoxin
Toxin B: cytotoxin
what is a major cause of hospital acquired infections in humans getting antibiotic treatment
C. difficile
T/F C. diff can be isolated from meat
T
what is an important diagnostic test for C. difficile
glutamate dehydrogenase (GDH) ELISA
how do we treat C. difficile
antibiotics, probiotics, fecal transplant
what causes blackleg
C. chauveoi
what causes pseudoblackleg
C. septicum, C. novyi
what is blackleg and when does it commonly occur
acute necrotizing myostitis and systemic toxemia caused by C. chauvoei
what type of year is blackleg common and why
in the summer; it is caused by ingestion of spores in the soil
what is the pathogenesis of blackleg
ingestion of spores -> spores travel via the blood to the muscles -> anoxia activates the spores -> necrotizing myostitis -> toxemia -> death
how do we diagnose blackleg based on signs
swollen legs, gas under skin
C. chauvoei is susceptible to ____________ and resistant to ____________
penicillin; aminoglycosides
what species cause gas gangrene
C. perfringens Type A; C. chauvoei, C. septicum, C. novyi, C. sordellii
gas gangrene mainly affects what species
ruminants and horses
what is the treatment for gas gangrene
surgical debridement and antibiotics
what is the structure of C. tetani
tennis racket (rod-terminal spores)
where is C. tetani found and in what species specifically (what is most susceptible)
intestine and manure; especially horses
what species can develop tetanus
ALL
what is the pathogenesis of C. tetani
toxin produced at infection site (ex. deep wound) -> travels up axons to CNS -> goes to inhibitory neuron -> inhibits GABA/glycine release -> spastic paralysis
how do we treat tetanus
dark, quiet environment, mm relaxants, respirator
prevent with vaccination, toxoid
what produces the most potent toxin known
C. botulinum
how does botulism typically happen
ingestion of the preformed toxin from the environment
what is the pathogenesis of botulism
the toxin is usually ingested -> impacts cholinergic presynaptic cells -> inhibits ACh release
how do we diagnose butulism
toxin test in mice , PCR
