1. (Gram negative rods enteric tract)
Enterobacteriaceae I
(Gram negative rods enteric tract)
Lecture 34
Faculty: Dr. Alvin Fox

2. 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

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

4. Enterobacteriaceae gastrointestinal diseases Escherichia coli
Salmonella
Shigella
Yersinia entercolitica

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

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

7. E. coli fimbriae
Type 1
mannose P
galactose
glycolipids
glycoproteins

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

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

10. Enterobacteriaceae
other sites
identified biochemically

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

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

13. Caption: E. coli
Escherichia coli

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

15. Enterohemorrhagic E. coli
Usually O157:H7
Transmission electron
micrograph
Flagella

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

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

18. Enterotoxigenic E. coli
diarrhea like cholera
milder
travellers diarrhea

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

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

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

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

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

24. Shigella
Modified from Fig, Dennis Kunkel

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

26. Shigellosis
within 2-3 days
epithelial cell damage
Gut lumen

27. Shiga toxin enterotoxic cytotoxic inhibits protein synthesis
lysing 28S rRNA

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

29. Treating shigellosis manage dehydration
patients respond to antibiotics
disease duration diminished

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 |

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

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

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

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

35. S. cholerae-suis much less common septicemia
antibiotic therapy essential