Gram Negatives Flashcards
Pathogenic categories of E. coli
enterotoxigenic (ETEC) Enteropathogenic (EPEC) enteroinvasive (EIEC) Enterohemorrhagic (EHEC) Necrotoxigenic (NTEC)
Which strain of E. coli produces heat-stable (ST) and heat-labile (LT) toxins?
enterotoxigenic
How does EPEC cause disease?
attaches to epithelial cells and destroys them (no toxin production)
this e. coli strain causes neonatal watery diarrhea by penetrating epithelial cells
EIEC
EHEC produces _____ toxins which are similar to Shiga toxins; what do they cause?
Virotoxins
cause edema disease
Survival of colibacillosis in poultry leads to what disease?
fibrinopurulent airsacculitis (must condemn carcass)
Common to see an asymptomatic carrier state with _________?
Salmonella
T/F: ALL salmonella can be invasive
True (only SOME e. coli can)
Two important virulence factors for salmonella?
Invasiveness
LPS
Causes typhoid fever in humans
Salmonella typhi
Strain of salmonella that’s most prevalent in animal infections
Salmonella typhimurium
Causes fowl typhoid
Salmonella gallinarum
Which strain of salmonella can infect a variety of animals and is also responsible for GE in humans
Salmonella enteritidis
Is salmonella extra or intracellular?
intracellular
Important in catfish industry; causes skin lesions and septicemia in catfish
Edwardsiella ictaluri
Commonly causes cytitis and UTIs
Proteus spp.
Which gram negative forms intensively red pigmented colonies?
Serratia
Etiologic agent of the plague?
Yersinia pestis
Which domestic spp. can contract the plague? What are the 2 disease forms?
Cats
Bubonic form–buboes near fleabite
pneumonic form–aerosol transmission
Important foodborne pathogen that can be isolated using cold enrichment
Yersinia enterocolitica
T/F: Freezing will kill enterbacteriaceae
False
Why don’t bacterin vaccines work for salmonella?
doesn’t elicit necessary cell-mediated immunity
Etiologic agent of cattle shipping fever
Mannheimia haemolytica
Is M. haemolytica intracelluar?
No
Virulence factors of M. haemolytica. Which are protective antigens?
Leukotoxin
Capsule
BOTH
How does leukotoxin work?
forms pores in leukocytes and causes hydrolytic enzymes to leak out, causing tissue damage and amplifying the immune response
Most of the injury from disease with M. haemolytica is caused by
host immune system over response
5 diseases that can be caused by Pasteurella multocida
Bronchopneumonia hemorrhagic septicemia Fowl cholera Atrophic rhinitis Snuffles
How can you differentiate hemorrhagic septicemia from anthrax?
Gram stain
Why are bacertins not ideal for fowl cholera?
only protect from homologous strains
P. multocida’s dermonecrotic toxin targets what?
osteoclasts (causes bone breakdown)
Name the associated spp. Brucella: abortus melitensis suis canis ovis
cattle goats pigs dogs sheep
Is brucella a commensal organism?
NO; a positive culture is diagnostic
Classic clinical sign of infection with brucella
late term abortion
Importance of erytritol?
located in high concentrations in bovine repro tract; brucella has tropism for it
Which brucella spp. causes the most serious disease in humans?
B. melitensis
Which brucella spp. most commonly infects humans? why?
B. suis; prolonged bacteriemic stage
3 diseases associated with Bordetella bronchiseptica
kennel cough
atrophic rhinits
snuffles
Two diseases shared by P. multocida and B. bronchiseptica?
Snuffles
Atrophic rhinitis
How does B. bronchiseptica cause a cough?
destroys ciliated epithelium
How does B. bronchiseptica’s dermonecrotic toxin differ from P. multocida’s? can they be present in disease together?
Targets osteoblasts (prevents new bone formation) Yes
The live avirulent vaccine for B. bronchiseptica offers what type of immunity?
mucosal
why does the acellular vaccine for B. bronchiseptica offer the lowest risk of toxicity?
doesn’t contain LPS
Disease caused by Bordetella avium?
turkey coryza
Which is less fastidious:
Haemophilus
Histophilus
Histophilus (doesn’t need Factors X or V)
TEME is caused by
Haemophils somnus/ Histophilus somni
3 main types of disease caused by histophilus/haemophilus?
repro tract
respiratory tract
joints
Which bacteria has Fc receptors as a virulence factor? What do they do?
Haemophilus/histophilus
bind host Abs to prevent lysis
Causes Glasser’s disease in pig
Haemophils parasuis
Causes coryza of chickens
Avibacterium paragallinarum
Causes contagious equine metritis (CEM)
Taylorella equigenitalis
2 important species of actinobacillus
A. pleuropneumoniae
A. suis
A. pleuropneumoniae cyottoxins are similar to?
Leukotoxins from M. haemolytica (pore-forming)
Subclinical infections by A. pleuropneumoniae stimulated by stress tend to cause which form of disease
peracute/acute
Causes fatal septicemia of piglets
A. suis
Which two sites should not be cultured when checking for actinobacillus infection? Why?
Tonsils and URT
commensal to these areas
Causes wooden tongue in cattle
A. lignieresii
Causes sleepy foal disease
A. equuli
Causative agent of infectious bovine keratoconjunctivitis?
Moraxella bovis
M. bovis can be tramitted by
face flies
direct contact
Photophobia and conjuctivitis are associated with?
M. bovis infection (infectious bovine keratoconjunctivitis)
One of the most resistant bacteria known
Pseudomonas aeruginosa
Etiologic agent of Tularemia
Francisella tularensis
Two unique things about F. tularensis
VERY invasive (can penetrate skin) requires cysteine for growth
How can tularemia be transmitted?
By blood sucking arthorpods from infect rabbits (rabbit fever)
Sheep that are malnourished and covered in ticks are likely to have what diseae
ovine tularemia
Which spirochete can be readily grown in culture?
Borrelia (the rest cannot be cultured)
Etiologic agent of lyme disease
Borrelia burgdorferi
Which disease is characterized by acute onset of lamness or chronic, intermittent lameness
lyme disease
Causative agents of
1) fowl spirochetosis
2) swine dysentery
Borrelia anserine
brachyspira hyodysenteriae
