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(Gram negative rods enteric tract)

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Presentation on theme: "(Gram negative rods enteric tract)"— Presentation transcript:

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

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