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

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Presentation on theme: "1 Faculty: Dr. Alvin Fox Enterobacteriaceae I Enterobacteriaceae I (Gram negative rods enteric tract) Lecture 34."— Presentation transcript:

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

2 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. coliHelicobacter pylori Enteroinvasive E. coli

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

4 4 Enterobacteriaceae gastrointestinal diseases – Escherichia coli – Salmonella – Shigella – Yersinia entercolitica

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

6 6 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

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

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

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

10 10 other sites other sites identified biochemically – identified biochemically Enterobacteriaceae

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

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

13 13 Caption: E. coli Escherichia coli

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

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

16 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 17 Vero toxin Vero toxin – “shiga-like toxin” Hemolysins Hemolysins Enterohemorrhagic E. coli

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

19 19 Enterotoxigenic E. coli Heat labile toxinHeat labile toxin –like choleragen –Adenyl cyclase activated –cyclic AMP –secretion water/ions Heat stable toxinHeat stable toxin –Guanylate cyclase activated –cyclic GMP –uptake water/ions –uptake water/ions

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

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

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

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

24 24 Shigella Modified from Fig, Dennis Kunkel

25 25 Shigella S. flexneri, S. boydii, S. sonnei, S. dysenteriaeS. flexneri, S. boydii, S. sonnei, S. dysenteriae –bacillary dysentery – shigellosis bloody fecesbloody feces intestinal painintestinal pain puspus

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

27 27 Shiga toxin enterotoxicenterotoxic cytotoxiccytotoxic inhibits protein synthesisinhibits protein synthesis – lysing 28S rRNA

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

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

30 30 [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 | Salmonella

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

32 32 Salmonellosis S. enteritidisS. enteritidis –the common salmonella infection –poultry, eggs –no human reservoir –Gastroenteritis nauseanausea vomitingvomiting non-bloody stoolnon-bloody stool self-limiting (2 - 5 days)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 33

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

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

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