Enterobacteriaceae (Gram negative rods enteric tract)

1.

Enterobacteriaceae
(Gram negative rods enteric tract)
1

2. Key Words

Opportunistic diseases
Diarrhea
Dysentery
Urinary tract infections
Pili
Lactose positive/negative
Enterohemorrhagic E. coli
- Vero toxin (Shiga-like)
- Hemolysin
Enterotoxigenic E. coli
- Heat stable toxin
- Heat labile toxin
Enteropathogenic E. coli
Enteroaggregative E. coli
Enteroinvasive E. coli
Shigella
- Bacillary dysentery
- Shiga toxin
Salmonella enteritidis
Salmonellosis
Salmonella cholerae-suis
Salmonella typhi
- Typhoid
- Vi
Yersinia entercolitica
Vibrio cholerae
Choleragen (cholera toxin)
Campylobacter jejuni
Helicobacter pylori
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3.

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

• gastrointestinal diseases
– Escherichia coli
– Salmonella
– Shigella
– Yersinia entercolitica
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5.

Reiter's syndrome
• Histocompatibility antigen (HLA) B27
– Enterobacteriaceae
*Salmonella
*Shigella
*Yersinia
– Non-Enterobacteriaceae
*Campylobacter
*Chlamydia
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6.

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

Type 1
mannose
P
galactose
– glycolipids
– glycoproteins
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8. Enterobacteriaceae

• gram negative facultative anaerobic rods
– oxidase negative (no cytochrome oxidase)
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9.

Feces
• E. coli
– lactose positive
– not usually identified
– lactose positive sp. common, healthy intestine
• Shigella, Salmonella,Yersinia
– lactose negative
– identified
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10.

Enterobacteriaceae
• other sites
– identified biochemically
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11. Serotypes

• reference laboratory
– antigens
• O (lipopolysaccharide)
• H (flagellar)
• K (capsular)
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12. Diarrhea (watery feces) and Dysentery (blood in stools)

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13. Caption: E. coli

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14.

Escherichia coli
• E. coli and Shigella
– genetically very similar
– separated for historical reasons
– overlap in pathogenesis
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15.

Enterohemorrhagic E. coli
• Usually O157:H7
Flagella
Transmission electron
micrograph
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16. 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
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17.

Enterohemorrhagic E. coli
• Vero toxin
– “shiga-like toxin”
• Hemolysins
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18.

Enterotoxigenic E. coli
• diarrhea like cholera
• milder
• travellers diarrhea
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19. 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
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20.

Enteropathogenic E. coli
destruction of surface microvilli
• fever
Gut lumen
• diarrhea
• vomiting
• nausea
• non-bloody stools (not generally seen as dysentery)
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21.

Enteroaggregative
• Brick-like
bacterial aggregates - cell surfaces
• Mucus biofilm inhibits fluid absorption
• Diarrhea
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22.

Enteroinvasive E. coli (EIEC )
• Dysentery
- resembles shigellosis
Gut lumen
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23. Treatment -gastrointestinal disease

• fluid replacement
• antibiotics
– not used usually unless systemic
–e.g. hemolytic-uremia syndrome
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24. Shigella

Modified from Fig, Dennis Kunkel
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25. Shigella

• S. flexneri, S. boydii, S. sonnei, S.
dysenteriae
– bacillary dysentery
– shigellosis
• bloody feces
• intestinal pain
• pus
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26. Shigellosis

• within 2-3 days
– epithelial cell damage
Gut lumen
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27. Shiga toxin

• enterotoxic
• cytotoxic
• inhibits protein synthesis
– lysing 28S rRNA
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28. Shigellosis

• man only "reservoir"
• mostly young children
– fecal to oral contact
– children to adults
• transmitted by adult food handlers
– unwashed hands
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29. Treating shigellosis

• manage dehydration
• patients respond to antibiotics
– disease duration diminished
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30.

Salmonella
[417
]
Caption: Salmonella typhi -
Gram-negative, enteric, rod prokaryote (dividing); causes typhoid fever.
Magnification*: x5,530
Type: SEM
Keywords: 96430B.TIF bacilli bacillus bacteria bacterial pathogen bacterium division Gram-negative human disease infection prokaryote rod Salmonella
typhi typhoid fever enteric bacterial pathogen intestinal tract infection SEM |
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31. Salmonella

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

• S. enteritidis
– the common salmonella infection
– poultry, eggs
– no human reservoir
– Gastroenteritis
nausea
vomiting
non-bloody stool
self-limiting (2 - 5 days)
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33. 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
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34. Salmonellosis

Gut lumen
uncomplicated cases (the vast majority)
antibiotic therapy not useful
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35. S. cholerae-suis

• much less common
• septicemia
• antibiotic therapy essential
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