1 / 35

Faculty: Dr. Alvin Fox

Enterobacteriaceae I (Gram negative rods enteric tract ) Lecture 34. Faculty: Dr. Alvin Fox. Key Words. Opportunistic diseases Shigella Diarrhea - Bacillary dysentery Dysentery - Shiga toxin Urinary tract infections Salmonella enteritidis Pili Salmonellosis

salene
Télécharger la présentation

Faculty: Dr. Alvin Fox

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. EnterobacteriaceaeI (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 PiliSalmonellosis Lactose positive/negative Salmonella cholerae-suis EnterohemorrhagicE. coli Salmonella typhi - Vero toxin (Shiga-like) - Typhoid - Hemolysin - Vi EnterotoxigenicE. coli Yersiniaentercolitica - Heat stable toxin Vibriocholerae - Heat labile toxin Choleragen (cholera toxin) EnteropathogenicE. coli Campylobacter jejuni EnteroaggregativeE. coliHelicobacter pylori EnteroinvasiveE. coli

  3. Opportunistic diseases -Enterobacteriaceae • septicemia, • pneumonia, • meningitis • urinary tract infections CitrobacterEnterobacter 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 cytochromeoxidase)

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

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

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

More Related