Bacteriology 9: Gram - enteric bacteria Flashcards
Will you see gram - cocci ?
NO
Gram - are what morphology?
Rods
What are the families of bacteria?
Enterobacterales
Pasteurellaceae
Misellanious
Enterbacterales are oxidase poisitive or negative?
Negative (-)
How many generas do Enterbacterales have?
50
we focus on 5
-escerichia
-salmonella
-Yersinia
-Klebsiella pneumoniae
-Proteus
Shared features of Enterbacterales?
gram -
faculatatively anaerobic
oxidase negative
MOTILE (virulence factor)
similar colonies in BLOOD agar
grow on MACCONKEY’S AGAR
-tolerate bile salts
-lactose ferm is variable
How do you separate Lactose fermentation?
+ =
E.coli
Klebsiella
-=
Proteus
Salmonella
Yersinia
Are all Enterbacterales the same pathogenicity?
No
What is the differential diagnosis list?
VINDICATE
V=vascular
I=infection
N=neoplasia
D= degeneration
I= inflammation
C= congenital
A=autoimmune
T=Trauma
E= endocrine
Ecoli in our case caused what kind of disease?
Pyometra
In our case the uterus was infected what kind of site is this?
Sterile site
4pt rule:
-sample collected correctly
-evidence of inflammation (many neutrophils-left-shift)
-evidence of bacteria
-did the bacteria have the OPPORTUNITY and the ABILITY to cause the disease
E. coli comes from where?
Normal flora in GI tract
-ilium and LI
one of first organism in neonatal GIT w/n hours
Survive well in environment
-COLIFORM good indicators in environment (water and soil, etc.)
E.coli transmission occurs how?
Depends on site of infection:
- fecal oral
-inhalation
-direct inoculation
-ascending infectiosn
–cystitis
–pyometra
–transient in Uro. tract
E.coli key point is?
VERY diverse
NOT all strain of this disease are virulent
How does E.coli cause disease?
Strain with virulence factors
-attachment
-avoidance of phagocytosis
-cellular effects
-systemic effects
Contribution of virulence factor depends on SITE OF INFECTION
Non-enteric infections for E.coli ?
Attachment
Avoidance
Cellular toxicity
System effects -endotoxins
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Key point of E.coli?
good OPPORTUNISTIC pathogen
enterobacterales can also cause multiple types of infection but E.coli does it BEST
How to diagnosis E.coli ?
Usually collecting samples from STERILE SITE
4pt rule
-especially critically evaluating your sample collection!
Treatment of E.coli ?
VERY drug resistance
Relies on susceptibility testing
ANCILLARY THERAPIES
-surgery/drainage/debridement
-fluid therapy
-anti-endotoxin therapies
Characteristics of Salmonella?
S. Enterice
S. bongeri
distinguished by set of surface antigens
Where does Salmonella come from?
NOT part of normal flora
CARRIER ANIMALS
-in their GI tract
Survive LONG time in environment
Transmission of Salmonella?
Fecal-oral
-reptiles
-cattle
-horses
-others
Recurdesence
-when the Salmonella comes back after being dormant in host
How does Salmonella cause disease?
Avoidance of killing by phagocytes
-FACULTATICE INTRACELLULAR PARASITES
-live in macrophages
Systemic carrier states
-NOT just intestine
-live in macrophages
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What diseases does Salmonella cause?
3 main:
ENTERITIS
-horse/cattle
-damages intestinal cells
SEPTICEMIA with localization
-neonatal animals
-lungs, jts, kidnets, heart, spleen, etc.
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CARRIER STATE
-ALL
-facultative INTRA cellular parasite
-macrophages transport to LN, etc. can be there for weeks to yeras
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