Enterobacteriaceae (Gram negative rods enteric tract) презентация

Key Words
Opportunistic diseases Shigella
Diarrhea - Bacillary dysentery
Dysentery - Shiga toxin
Urinary tract infections Salmonella enteritidis
Pili Salmonellosis
Lactose positive/negative Salmonella cholerae-suis
Enterohemorrhagic E. coli Salmonella typhi
- Vero toxin (Shiga-like) - Typhoid
- Hemolysin - Vi
Enterotoxigenic E. coli Yersinia entercolitica
- Heat stable toxin Vibrio cholerae
- Heat labile toxin Choleragen (cholera toxin)
Enteropathogenic E. coli Campylobacter jejuni
Enteroaggregative E. coli Helicobacter pylori
Enteroinvasive E. coli

septicemia,
pneumonia,
meningitis
urinary tract infections
Citrobacter Enterobacter
Escherichia
Hafnia
Morganella
Providencia
Serratia
Opportunistic diseases
-Enterobacteriaceae

Enterobacteriaceae
gastrointestinal diseases
Escherichia coli
Salmonella
Shigella
Yersinia entercolitica

Histocompatibility antigen (HLA) B27
Enterobacteriaceae
Salmonella
Shigella
Yersinia
Non-Enterobacteriaceae
Campylobacter
Chlamydia
Reiter's syndrome

community acquired
otherwise healthy people
Klebsiella pneumoniae
respiratory diseases
prominent capsule
urinary tract infection
fecal contamination
E. coli
Proteus
urease (degrades urea)
alkaline urine
Enterobacteriaceae

E. coli fimbriae
mannose
Type 1
galactose
glycolipids
glycoproteins
P

Enterobacteriaceae
gram negative facultative anaerobic rods
– oxidase negative (no cytochrome oxidase)

E. coli
lactose positive
not usually identified
lactose positive sp. common, healthy intestine
Shigella, Salmonella,Yersinia
lactose negative
identified
Feces

other sites
identified biochemically
Enterobacteriaceae

Serotypes
reference laboratory
antigens
O (lipopolysaccharide)
H (flagellar)
K (capsular)

Diarrhea (watery feces)
and Dysentery (blood in stools)

Caption: E. coli
Escherichia coli

E. coli and Shigella
genetically very similar
separated for historical reasons
overlap in pathogenesis
Escherichia coli

Enterohemorrhagic E. coli
Usually O157:H7
Flagella

Transmission – meat products or sewage-contaminated vegetables
Hemorrhagic
Bloody dysentery
copious diarrhea
few leukocytes
afebrile
hemolytic-uremic syndrome
hemolytic anemia
thrombocytopenia (low platelets)
kidney failure

Vero toxin
“shiga-like toxin”
Hemolysins
Enterohemorrhagic E. coli

Enterotoxigenic E. coli
diarrhea like cholera
milder
travellers diarrhea

Enterotoxigenic E. coli
Heat labile toxin
like choleragen
Adenyl cyclase activated
cyclic AMP
secretion water/ions
Heat stable toxin
Guanylate cyclase activated
cyclic GMP
uptake water/ions

Enteropathogenic E. coli
destruction of surface microvilli
fever
diarrhea
vomiting nausea
non-bloody stools (not generally seen as dysentery)
Gut lumen

Enteroaggregative
Brick-like bacterial aggregates - cell surfaces
Mucus biofilm inhibits fluid absorption
Diarrhea

Dysentery
- resembles shigellosis
Enteroinvasive E. coli (EIEC )
Gut lumen

Treatment -gastrointestinal disease
fluid replacement
antibiotics
not used usually unless systemic
e.g. hemolytic-uremia syndrome

Shigella
Modified from Fig, Dennis Kunkel

Shigella
S. flexneri, S. boydii, S. sonnei, S. dysenteriae
bacillary dysentery
shigellosis
bloody feces
intestinal pain
pus

Shigellosis
within 2-3 days
epithelial cell damage
Gut lumen

Shiga toxin
enterotoxic
cytotoxic
inhibits protein synthesis
lysing 28S rRNA

Shigellosis
man only "reservoir"
mostly young children
fecal to oral contact
children to adults
transmitted by adult food handlers
unwashed hands

Treating shigellosis
manage dehydration
patients respond to antibiotics
disease duration diminished

Salmonella

Salmonella
2000 antigenic "types”
genetically single species
S. enterica
disease category
S. enteritidis
many serotypes
S. cholerae-suis
S. typhi

Salmonellosis
S. enteritidis
the common salmonella infection
poultry, eggs
no human reservoir
Gastroenteritis
nausea
vomiting
non-bloody stool
self-limiting (2 - 5 days)

Control of salmonellosis
Monitoring of food in the US is limited
microbiology is difficult
Regulation is not optimal
Chickens are not vaccinated in US
UK, salmonellosis largely erradicated

Salmonellosis
uncomplicated cases (the vast majority)
antibiotic therapy not useful
Gut lumen