Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BACTERIOLOGY > 15 – E. Coli > Flashcards

15 – E. Coli Flashcards

1
Q

Microbial characteristics

A
  • Gram-negative fermentative rods
  • Biocontainment level 1-3
  • Commonly divided based on ability to FERMENT LACTOSE
  • Blood agar: colonies are typically grey (small round colonies to swarming plate)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

E.coli on blood agar and MacConkey

A
  • Pink colouration reflects LACTOSE FERMENTATION
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Proteus mirabilis on blood aga

A
  • Swarm entire plate!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Natural host or habitat

A
  • Widely disseminated and ubiquitous (environment, intestinal and respiratory tract)
  • Some occupy specialized niches (Salmonella typhi=only humans reservoir)
  • Some ‘generalist nature’ in their name
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Taxonomy

A
  • Differential agar plates useful
  • Biochemical tests
  • Tube motility tests
  • Triple Sugar Iron (TSI)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

E. coli genes

A
  • Many core genes
  • Accessory genes continues to grow!
  • *tremendous diversity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Virulence factors: 2 broad organizations

A
  • Diarrheagenic E. coli (DEC)
  • Extraintestinal pathogenic E. col (ExPEC)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Virulence factors: diarrheagenic E. coli (DEC)

A
  • Shiga toxin producing (STEC)
  • Enterotexigenic (ETEC)
  • Enteropathogenic (EPEC)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Virulence factors: extraintestinal pathogenic E. coli (ExPEC)

A
  • Uropathogenic (UPEC)
  • Sepsis-causing (SEPEC)
  • Avian pathogenic (APEC)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

E. coli STEC: virulence factors

A

*Shiga toxin family
- Stx: multiple variants, act by interfering with protein synthesis
o Causes edema and hemorrhage
- Phage mediated:
o Fluoroquinolones and TMS may increase expression
*intimin: eae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

E. coli ETEC cause of

A
  • Neonatal colibacillosis in ruminants and pigs
    o ‘weanling diarrhea’ and ‘travellers diarrhea in people
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

E. coli ETEC species and age specific pathogenicity

A

*presence of receptors in host
- F4 fimbriae: receptors found in piglets up to 8 weeks old
- F5 fimbriae: receptors found in calves in first few days of life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

E. coli ETEC toxins include

A
  • Heat labile toxin (LT)
  • Heat stable toxin (ST)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

E. coli ETEC: heat labile toxin (LT)

A
  • Increase cAMP levels leading to increased fluid and electrolyte excretion
  • Similar to toxin produced by Vibrio cholerae
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

E. coli ETEC: heat stable toxin (ST)

A
  • Interferes with enteric nervous system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

E. coli EPEC: histologically see attaching and effacing lesions

A
  • bacteria seen closely attached to enterocytes
  • heavily colonized enterocytes may have intracellular bacteria
  • mucosal erosions are present
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

E. coli EPEC key virulence factor

A
  • eae (enterocyte attaching and effacing)
    o encodes an intimin which allows bacteria to attach
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

E. coli EPEC dogs

A
  • increasingly recognized
  • may mimic typical parvovirus presentation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

E. coli Uropathogenic

A
  • infections opportunistic: ascending from urethra
  • intracellular infections
  • many virulence factors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

E. coli uropathogenic virulence factors

A
  • fimbriae: P. fimbriae protect against phagocytosis
  • flagella: swimming up kidneys from bladder
  • siderophores: aerobacin (acquisition of iron)
  • alpha hemolysi: pore-forming
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

E. coli Septicemic virulence factors

A
  • fimbriae
  • capsule
  • siderophores
  • endotoxin
  • colicin V
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

E. coli APEC virulence factors

A
  • fimbriae
  • invasins
  • hemolysins
  • siderophores
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

E. coli piglet diarrhea

A
  • F4 E.coli
  • Neonatal diarrhea (more often affects gilt litters)
  • Youn piglet diarrhea (until weaning)
  • Post-weaning diarrhea
24
Q

Treatment of E. coli piglet diarrhea

A
  • Antimicrobials (based on AST if possible)
  • Fluid therapy
25
Q

Management of E. coli piglet diarrhea

A
  • Keep barn clean: build-up of pathogens=RISK factor
  • Keep piglets warm (30-34degrees C for unweaned) and DRY
26
Q

E. coli calf scours

A
  • Calves and sheep (F5 E. coli)
  • Receptors only expressed in first 1 week of life
  • Watery and NOT bloody
  • Polymicrobial infections common: cause expression of F5 receptors in older calves
    o Rotavirus
    o Cryptosporidium parvum
  • *other strains of E. coli can cause systemic infections in calves (ascending from umbilicus)
27
Q

E. coli edema disease (pigs)

A
  • Peracute disease
  • Differential diagnosis for Clostridoides difficile
  • Fecal-oral transmission
  • Following attachment to intestinal epithelium=production of a Shiga-toxin
28
Q

E. coli edema disease (pigs): peracute disease

A
  • Often found dead
  • Edema of eyelids, forehead, stomach and spiral colon
  • Neurological signs: infarctions of brain
29
Q

E. coli hamburger disease (humans)

A
  • Severe, bloody diarrhea in people
  • Associated with the O157:H7 strain
  • Important foodborne pathogen (most commonly beef)
  • Fecal-oral transmission can result in zoonotic spread
    o Contaminated water or direct contact with animals
30
Q

E. coli hamburger disease (humans): severe, bloody diarrhea

A
  • Hemorrhagic colitis
  • Hemolytic-uremic syndrome
    o Hemolytic anemia
    o Kidney failure
    o thrombocytopenia
31
Q

E. coli mastitis (cattle)

A
  • coliform mastitis
  • major cause of mastitis in well managed herds
  • E. coli shed in feces and enters teat from environment
  • Presentation varies (mild to severe)
  • Some cows respond to invasion early and clear E. coli from teat
  • Some are slower=allows cells to multiply
  • *30-40% of severely affected become bacteremic
32
Q

Coliform

A
  • Relating to gram-negative rod-shaped bacteria (ex. E. coli) found in intestine
  • Used as indicators of fecal contamination
33
Q

E. coli mastitis (cattle): cows that are slower and allow cells to multiply

A
  • Multiply in teat
  • Endotoxin released from dead cells
  • Leads to cytokine storm and systemic inflammation
34
Q

E. coli mastitis (cow) treatment

A
  • systemic and intramammary antibiotics
35
Q

E. coli mastitis (cow) management

A
  • removing organic bedding materials that support E. coli growth
36
Q

Colibacillosis

A
  • infection with avian-pathogenic E. coli
    o make their way into the egg
  • constellation of symptoms
  • found in environment, from hens feces and exploding eggs
    o gas produced by bacteria can cause egg to burst
37
Q

Symptoms of colibacillosis

A
  • Omphalitis: often involves yolk sac
  • coli-septicemia
  • swollen-head syndrome
  • air sacculitis
38
Q

omphalitis

A
  • inflammation of navel
39
Q

E. coli omphalitis (chickens and turkeys) numerous presentations

A
  • dead embryos
  • swelling and edema of navel
  • distended abdomen
  • *’mushy chicks’: body wall overlying yolk sac degenerates
40
Q

E. coli omphalitis (chickens and turkeys): treatment

A
  • Antimicrobials (area of debate)
41
Q

E. coli omphalitis (chicken and turkeys): management

A
  • Keep things clean (discard eggs and exploders)
  • Disinfecting eggs within 2 hours of laying
  • Good quality diets may help
  • Possible vaccination
42
Q

E. coli UTI (dogs)

A
  • 14% of dogs (most commonly spayed females) have UTIs, 50% implicated with E. coli
  • Less common in cats than dogs
  • Classified by anatomical site
43
Q

Lower UTI

A
  • Bladder and urethra
    1. Sporadic cystitis
    1. Recurrent cystitis
44
Q

Sporadic cystitis: lower UTI

A
  • Female otherwise healthy, non-pregnant
  • No anatomical or functional abnormalities or relevant co-morbidities
  • NOT a repeat infection
45
Q

Upper UTI

A
  • Kidney and ureter
46
Q

Treatment of UTI if sporadic cystitis

A
  • Can treat empirically
  • *collect urine to culture
47
Q

Treatment of UTI if anything else

A
  • MUST be based on susceptibility tests
48
Q

Treatment of UTI

A
  • Antibiotic therapy depends on site of infection
  • Addressing underlying disease
49
Q

Management of UTI

A
  • Get a diagnosis!
    o Why does this animal have a UTI?
  • Address underlying disease!
50
Q

Sample collection

A
  • Diarrhea: colonic tissue for histopathology
  • Mastitis: milk
  • Omphalitis: samples from dead chicks (inner viscera)
  • Mortality event: whole animals (pathological lesions, histology, culture)
  • UTI: aseptically collect urine (preferably cystocentesis)
51
Q

Lab ID

A
  • Easy to grow with standard cultures
  • *MacConkey provides very useful first clue
  • Biochemical tests
  • MALDI-TOF
  • Molecular methods
  • NAAT tests: to help ID pathogenic types
  • Histology to ID/characterize lesions
52
Q

Zoonotic/interspecies transmission: food borne transmission

A
  • Enterohemorrhagic E. coli
    o Maintained by healthy cattle, shed in feces
    o Cattle unaffected=LACK TOXIN RECEPTOR
  • *possibly a source of antimicrobial resistance
53
Q

Zoonotic/interspecies transmission: animal to human to animal to human

A
  • Less well defined=UNDERSTUDIED
54
Q

Standard precautions to prevent zoonotic/interspecies transmission

A
  • Hand washing
  • PPE
55
Q

Treatment options

A
  • Must be guided by susceptibility testing
56
Q

Drugs to avoid/intrinsic resistance

A
  • ALL enterobacterales intrinsically resistant to
    o Benzylpencillin
    o Glycopeptides
    o Fusidic acid
    o Macrolides
    o Lincosamides
    o Streptogramins
    o Rifampin
57
Q

Resistance is emerging! Be aware of

A
  • Broad spectrum beta-lactamases
  • Fluroquinolone resistance

BACTERIOLOGY (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions