Lecture 12 10/19/23 Flashcards
What are the general characteristics of gram neg. bacteria?
-outer membrane containing LPS
-majority are bacilli or coccobacilli
What are the characteristics of endotoxin/lipid A?
-released when bacteria dies
-contained in LPS
What test is used to detect endotoxin/lipid A?
limulus amebocyte lysate test
What is the effect of endotoxin?
generalized endotoxic shock effect
Where is endotoxin absorbed?
through damaged GI wall
How can LPS be beneficial?
development of innate immunity
What are the general characteristics of Enterobacteriaceae?
-facultative anaerobic rods
-reside in GI tract
-opportunistic
What are the characteristics of E. coli?
-present in mammal GI tracts
-can cause enteritis and extra-intestinal infections
What are the possible virulence factors of E. coli?
- capsule
-fimbrial adhesins
-enterotoxins
-cytotoxins
-siderophores
What is a serotype/serovar?
serologically distinguishable microorganism within a bacterial species
How are different strains of E. coli identified?
serotyping
What are the main toxins of E. coli?
-heat labile LT
-heat stable Sta and Stb
-shiga-like
What virulence factor is seen in attaching and effacing E. coli?
intimin
What diseases are caused by enterotoxigenic E. coli in calves?
-colibacillosis
-colisepticemia
Why are enterotoxigenic E. coli favored for attachment in newborns?
receptors for adhesins are expressed in the GI tract for the first week of life
What type of mastitis is caused by E. coli in adult cows?
coliform mastitis
What disease is caused by shigatoxigenic E. coli in weaned pigs?
edema disease
What diseases are caused by E. coli in dogs?
-colisepticemia
-pyometra
-lower UTI
What diseases are caused by E. coli in birds?
-septicemia
-omphalitis
-colispeticemia
-coligranuloma
How can E. coli be diagnosed?
-aerobic culture
-fecal culture
-PCR
-serological techniques
How should fecal samples be transported?
in screw cap containers while being refrigerated
How can E. coli be treated?
-supportive therapy
-antimicrobials
Why is it recommended to do AST with E. coli?
it has a lot of emerging antimicrobial resistance
Which antimicrobials is E. coli resistant to?
-penicillin/beta lactams
-trimethoprim
-tetracycline
-aminoglycosides
-fluoroquinolones
How can E. coli be controlled?
-management
-hygiene
-diet
-general health care
-bacterin and live attenuated vaccines
What are the characteristics of zoonotic E. coli?
-food born infections
-mostly shiga-toxin-producing EHEC strain O157:H7
-causes hemorrhagic enteritis, hemolytic uremic syndrome, and kidney failure
