GI Pathogens 2 Flashcards by Emma J

What are the general Characteristics of clostridia

Gram (+)
Anaerobic
Make spores
Exotoxins

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What are the 3 relevant types of clostridium

Clostridia (C. perfringens and difficile and piliforme)

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What are the 4 toxins produced by C. perfringens

o Alpha: phospholipase (dermonecrotic/hemolytic/cytolytic)
o Beta: pore forming activity/hemorrhagic (dermonecrotic/hemolytic/cytolytic)
o E: alter cell membrane permeability causing edema
o L: cytoskeleton damage = necrosis
o Theta: hemolysin (perfringolysin) - (form pores/cytolytic/osmotic diarrrhea)

Toxins: alpha toxin, most with theta toxin (cholesterol dependent cytolysin = perfringolysin)
5 toxinotypes: A, B, C, D, E – make 4 major toxins

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List a histotoxic and enteric clostridia

C. perfringens

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What type of toxin does type A C. perfringens have

Type A: alpha toxin (also theta toxin)

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What type of toxin does type B C. perfringens have

Type B: toxin A, B, e

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What type of toxin does type C C. perfringens have

Type C: toxin A, B

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What type of toxin does type D C. perfringens have

Type D: a, e

mainly produces epsilon toxin - converted to active form in intestine

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What type of toxin does type E C. perfringens have

Type E: A, l

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What is the disease manifestation of type A C. perfringens in poultry, pigs, horses, and cows

o Poultry: necrotic enteritis
o Suckling and feeder pigs: necrotizing enterocolitis
o Equine> hemorrhagic mucosal necrosis
o Beef: abomasal ulcer/tympany
o Dairy: necrotic enteritis in calf
o Adult cattle: haemorrhagic bowel syndrome

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What is the disease manifestation of type B C. perfringens

o Ovine hemorrhagic enterotoxemia
o Hemorrhagic enteritis

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What is the disease manifestation of type C C. perfringens

o Neonatal hemorrhagic or necrotizing enterotoxemia

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What is the disease manifestation of type D C. perfringens

o Ovine enterotoxemia

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What is the disease manifestation of type E C. perfringens

o Bovine hemorrhagic enteritis

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What C. perfringens toxin causes food poisoning

o CPE enterotoxin
 Zoonotic/cause food poisoning
 Pore forming (cytotoxic) and interfere with tight junctions (alter paracellular permeability)

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What are the associated lesions with type A C. perfringens

o Lesions
 ‘red gut’ – large sections of small intestine or red/purple and full of blood
 Sudden death in dairy/feedlot cow (enterotoxemia)

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What factors contribute to development of type D C. perfringens infection

o Associated with alteration in GI microbiota: diet change (high concentrate) – overeating disease
o Short course of disease > fatal

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What is the general pathogenesis of type A C. perfringens infection

o Pathogenesis
 Overgrowth of C. perfringens
 Enzymes allow cleavage of mucin on epithelium
 Act on TNFa = cause sloughing of epithelium
 Activate host proteases to cut off basal epithelium
 Phospholipase affect membranes of epithelium and vasculature
 = necrosis/hemorrhage/sloughing epithelium

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What are the lesions and main species affected by type D C. perfringens infection

o Lesions:
 Enterotoxemia
 Pulpy kidney
o Species: Calf/goat/horse/mostly lambs

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What are the clinical manifestations of C. difficile in pigs and people

C. Difficile: Clostridioides difficile
* Human: antibiotic associated diarrhea
o Diarrhea/pseudomembranous colitis/fulminant colitis
* Pig: neonatal (1-7d) = mesocolonic edema (full of yellow fluid)

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What is the main clinical consequence of C. difficile

Neutrophilic diarrhea

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What are the toxins produced by C. difficile and what are their functions

 TcdA acts on the apical side = disrupt tight junction = allow TcdB to enter and act on basal side of enterocyte

o Toxins: A (TcdA enterotoxin) + B (TcdB cytotoxin)
 Inactivate regulation of actin cytoskeleton = open tight junctions = cell death
 Increase proinflammatory cytokines + activate enteric NS = PMN chemotaxis and fluid secretion

 Form volcano lesions in intestine (inflame cells leak into lumen)

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How do you diagnose C. perfringens infection

Study These Flashcards

C. perfringens: PE/gross/histo lesions
o Anaerobic culture with double zone of hemolysis
o Multiplex PCR or ELISA = identify toxin

How do you diagnose C. difficile infection

Study These Flashcards

C. difficile: anaerobic culture
o Neutralization test/ELISA = identify toxin (best way for dx)

How to prevent clostridia in cattle

* 7 way cattle vaccine: C. chauveoi (blackleg) /septicum /sordelli (malignant edema)/novyi (black disease)/perfringens (3 types)

What are the general characteristics of C. piliforme

* Spore forming – can live 1 year in dirty bedding * Obligate anaerobic + obligate intracellular * Cause icterus: alter liver function

How to stain C. piliforme

* Gram (-) – but gram (+) under strictly anaerobic conditions - gram stain depends on the environment * Stain with silver stain or giemsa stain

What is the disease that C. piliforme causes in horses? How do they get it? Prognosis? Prevention?

* Tyzzers disease: foals o From ingestion of spores from environment o Unknown pathogenesis o Poor prognosis o No vaccine o Farm hygiene

What is the disease that C. piliforme causes in dog/cat? How do they get it? Main lesions? Prognosis?

* Tyzzers disease: dog/cat o Due to ingesting rodent feces with spores o Higher risk if stress/immunosuppressed o Lesions: thickened intestine mucosa in distal ileum and proximal colon + foamy dark brown feces o Poor prognosis = fatal

What is the pathogenesis of tyzzers disease in dogs/cats

o Locally proliferate in enterocytes – spread to liver – colonize hepatocytes = multifocal periportal hepatic necrosis due to toxin  Necrotic ileitis or colitis

What is the main risk factor for clostridium infection

Risk factors: disruption to normal GI microbiota

What is the morphologic characteristic of spirochetes

* Thin/long/flexible bacteria

How to stain spirochetes

* Silver stain (gram (-) but less effective than silver stain)

What are the 4 main genus's of spirochete GI bacteria

* Genus o Leptospira o Borrelia o Treponema o Brachyspira

What are the 2 main types of brachyspira causing GI disease

Brachyspira (B. hyodysenteriae and pilosicoli)

What animals does B. Hyodysenteriae infect

* Pigs – 6-12 weeks

What are the general characteristic s of B. Hyodysenteriae? What type of disease does it cause

* Infectious colitis * Oxygen tolerant anaerobe * Obligate symbiotic * Environmentally resistant

What are the clinical and gross signs of B. Hyodysenteriae

o Emaciation o Lots of mucus-y feces o Dehydration o Edema of large intestine walls o Low mortality but high production loss

How to diagnose B. Hyodysenteriae

* Diagnose: post mortem o Fluorescent stain o Anaerobic culture PCR

What is a main virulence factor of B. pilosicoli

B. pilosicoli * Virulence factors o Beta hemolysins (can kill cells)

What is the pathogenesis of B. pilosicoli

o Verry motile in mucin o Chemotaxis o Attach to apical membrane of enterocutes = loss of microvilli o Serine protease secretion = damage tight junctinos = parracytoss o chronic extracellular infection – in goblet cells and lamina propria o colonic malabsorption = osmotic diarrhea

What are the general characteristics of campylobacter spp.

* gram (-) * microaerophilic * commensal in intestines and repro tract

What are 3 relevant types of campylobacter spp

o C. fetus fetus and C. fetus venerealis = abortion o C. jejuni = enteritis

What are the main risk factors and clinical signs of C. jejuni? What else should be considered

* Zoonotic * Risk: young/immunocompromised * Clinically: self limiting diarrhea (+/- mucoid/blood) o Fever

How is diagnosis and treatment of C. jejuni complicated?

* Diagnosis: difficult to confirm in animals without diarrhea o Can worsen the effects of other GI pathogens * Treat: resistance is more common (resistant to fluoroquinolones)

What are the main types of helicobacter

* Types: o H. felis, bizzozeronii, heilmanni o H. pylori

What type of disease is helicobacter associated with

* Associated with chronic gastritis in dogs

What are the general characteristics of yersinia spp

* Family: Enterobacteriaceae (also salmonella/e. coli) * Gram (-) * Facultative anaerobe

What are the 3 main types of yersinia

o Y. pseudotuberculosis and enterocolitis o Y. pestis  Plague  Human/cat/rodent

What is the clinical manifestation of Y. pseudotuberculosis and enterocolitis and what species does it affect? How to prevent

 Enterocolitis/sporadic abortion – diarrhea  Farm animal/wildlife/humans – deer (common)/sheep  Vaccine available

What is the clinical manifestation of Y. pestis and what species does it affect

 Plague  Human/cat/rodent

What 4 pathogens cause enteric disease in cattle

Johnes dz Salmonella Clostridia Neonatal diarrhea - ETEC

What 4 pathogens cause enteric disease in horse

Salmonella Potomac horse fever Clostridium associated enterocolitis Lawsonia intracellularis

What 2 disease complexes and the associated pathogens cause enteric disease in foals

Bacterial enterocolitis in neonaatal foals - kleibsiella - salmonella - e. coli - clostridia haemorrrhagic diarrhea in foals - C. perfringens - Bacteroides fragilis - rhodococcuss equi

What 6 pathogens cause enteric disease in pigs

Salmonella C. difficile/perfringens (type C) ETEC Brachyspira hyodysenteriae (dysentery) or pilosicoli (spirochetosis) Lawsonia intracellularis

What 6 pathogens cause enteric disease in cat/dogs

Salmonella Campylobacter Helicobacter Shiegllosis Tyzzer's disease C. perfringens

GI Pathogens 2 Flashcards

(56 cards)