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ENTEROBACTERIACEAE

ENTEROBACTERIACEAE. Prof. Khalifa Sifaw Ghenghesh. Gram-negative rods Facultative anaerobes Oxidase-negative Most members are motile. Gastrointestinal diseases (Diarrhoea and Dysentery) Escherichia coli (Lac+) Salmonella (Lac-) Shigella (Lac-) Yersinia entercolitica (Lac-).

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ENTEROBACTERIACEAE

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  1. ENTEROBACTERIACEAE Prof. Khalifa Sifaw Ghenghesh

  2. Gram-negative rods • Facultative anaerobes • Oxidase-negative • Most members are motile

  3. Gastrointestinal diseases (Diarrhoea and Dysentery) • Escherichia coli(Lac+) • Salmonella (Lac-) • Shigella (Lac-) • Yersinia entercolitica (Lac-)

  4. SalmonellaE. coli

  5. Opportunistic diseases • septicemia, • pneumonia, • meningitis • urinary tract infections • Citrobacter • Enterobacter • Escherichia • Hafnia • Klebsiella • Morganella • Proteus • Providencia • Serratia

  6. IDENTIFICATION • In Stool: • E. coli • lactose positive • not usually identified • Common in healthy intestine • Shigella, Salmonella,Yersinia • lactose negative • identified • Other sites: • identified biochemically

  7. SEROTYPING • Reference laboratory: • antigens • O (lipopolysaccharide) • H (flagellar) • K (capsular)

  8. Escherichia coli

  9. Enteropathogenic E. coli (EPEC): • Adhere to surface of mucosal cells inducing dramatic alteration on microvilli and the rearrangement of the host cell actin cytoskeleton. • Adhesion is medicated by two genes: • A Plasmid-encoded gene (bfpA), responsible for the formation of the bundle forming pilus. • A chromosomal-mediated gene (eae) coding for the adhesion intimin. • fever • diarrhea • vomiting • nausea • non-bloody stools

  10. Enterotoxigenic E. coli (ETEC): • Cholera-like diarrhoea • milder • Travellers diarrhoea • Heat labile toxin (LT) • like choleragen (Cholera toxin) • activate enterocyte adenyl cyclase • cyclic AMP • chloride and water secretion >>Diarrhea • Heat stable toxin (ST) • activate enterocyte guanylate cyclase • cyclic GMP • Chloride and water secretion >> Diarrhea

  11. Enteroinvasive E. coli (EIEC): • Dysentery • resembles shigellosis

  12. Enterohemorrhagic E. coli (EHEC): • Usually O157:H7 • Meat • Hemorrhagic • bloody, copious diarrhea • few leukocytes • afebrile • Hemolytic-uremic syndrome • hemolytic anemia • thrombocytopenia (low platelets) • kidney failure • Vero toxin (Shiga-like): • 2 toxins: SLTI and SLTII (coded by sxt1 and sxt2)

  13. TREATMENT • Gastrointestinal disease: • Fluid replacement • Antibiotics • not used usually unless systemic • e.g. hemolytic-uremia syndrome • UTIs: • Antibiotic Sensitivity Is Necessary.

  14. Resistance of Escherichia coli isolated from urinary tract infections in Benghazi to antibiotics. ------------------------------------------------------------------------------------- Hospital Community Antibiotic acquired acquired (n=62) (n=148) ------------------------------------------------------------------------------------- Ampicillin 52(84)* 111(75) Carbenicillin 53(85) 117(79) Cephaloridine 22(35) 53(36) Chloramphenicol 37(60) 67(45) Gentamicin 19(31) 27(18) Nalidixic acid 3(5) 15(10) Nitrofurantoin 4(6) 10(7) Tetracycline 45(73) 121(82) Trimethoprim 52(84) 120(81) sulphamethoxazole*(%) -------------------------------------------------------------------------------------

  15. Shigella

  16. Bacillary Dysentery • Shigellosis • bloody faeces • intestinal pain • pus • 4 Major O Antigenic Groups: • Serogroup A = Sh. dysenteriae • Serogroup B = Sh. flexneri • Serogroup C = Sh. boydii • Serogroup D = Sh. sonnei • No H-Antigens.

  17. Shiga Toxin • enterotoxic • cytotoxic • inhibits protein synthesis • lysing 28S rRNA

  18. The Organism Survive the Passage Through the GIT. >> Due to O Antigen • Attach to Colonic Cells. • Penetrate the Epithelial Cells. >> "Invasiveness" "Inflamation, Cell Death, Ulceration, Impaired • Multiply Inside >> Colonic Fluid Absorbtion and a Discharge of Blood, Mucus and Pus" • Pass to Another Cell.

  19. Man only "reservoir" • Mostly young children • fecal to oral contact • children to adults • Transmitted by adult food handlers • unwashed hands

  20. Treating Shigellosis • Manage dehydration • Patients respond to antibiotics • disease duration diminished

  21. CONTROL • Adequate Sanitization. • Detection and Treatment of Carriers. • Carriers Should Not Be Allowed to Handle Food. • Proper Sewage Disposal and Chlorination of Water. • FLIES >>>>>>>>>>>>>>>>

  22. Information about Libyan children with diarrhea and their Shigella isolates Patient Sex Age Month of Length of Episode Species and (Mo) occurrence diarrhea per day serotype of (days) Shigella -------------------------------------------------------------------------------------------------------- 1. F 11 Sep 1 5 S. sonnei 2. F 30 Sep 2 3 S. flexneri type2 3. M 27 Oct 1 6 S. sonnei 4. F 18 Oct 1 8 S. flexneri type2 5. F 36 Oct 2 5-7 S. flexneri type2 6. M 7 Dec 7 7-8 S. flexneri type1 7. M 7 Apr 1 10 S. flexneri type2 8. M 13 Jun 10 6-7 S. flexneri type3 9. M 32 Jul 1 4 S. sonnei

  23. Information about Libyan children with diarrhea and their Shigella isolates Faeces with Presence of Patient Mucus Blood Fever Vomiting Species and serotype of Shigella --------------------------------------------------------------------------------------------------------------------- 1. + + -- --S. sonnei 2. -- -- -- --S. flexneri type2 3. -- -- + --S. sonnei 4. -- -- -- --S. flexneri type2 5. + + + --S. flexneri type2 6. -- -- + --S. flexneri type1 7. + + + +S. flexneri type2 8. + + + +S. flexneri type3 9. + + + + S. sonnei

  24. Salmonella

  25. More than 2000 antigenic types (Serotypes). • Salmonella Typhi • Salm. Enteritidis • Salm. Cholera-suis • Salm. Typhimurium • Genetically single species • Salmonella enterica • Salm. enterica serotype Typhi ANTIGENIC STRUCTURE: • O & H Antigens >>> Serotyping. • Vi-Antigen (protective) >>> Salm. Typhi.

  26. CLINICAL INFECTION AND PATHOGENSIS 1.S. Typhi, S. Paratyphi A and B: • Gastroenteritis, bacteremia and typhoid fever. • Typhoid Fever (Enteric fever): • Fever, headache, diarrhoea, and abdominal pain. • Human Carriers Are the Only Source of Infection. • Transmission: • contaminated food • water supply • poor sanitary conditions • Mortality Rate: • Relapse:

  27. 2. S. Enteritidis, S. Typhimurium, etc.. • Salmonellosis: • Self-limiting gastroenteritis with fever for <2 days and diarrhoea < 7 days. • Source: • poultry, eggs • no human reservoir • Transmission: • Pets:

  28. TREARMENT: • Supportive Therapy and Maintaining Fluid and Electrolyte Balance. • Enteric Fever or Septicaemia: • Antibiotics • essential • Carriers of Salm. typhi: • CONTROL: • Carriers: • Food Cooked Properly • Water Standards Be Observed.

  29. Salmonella Serotypes Isolated from Diarrhoeic Faeces in Tripoli (1975-1980) • S. Wien • S. Muenchen • S. Typhimurium Salmonella Serotypes Isolated from Children with Diarrhoea in Tripoli (1992-1993) • S. Saintpaul • S. Muenchen Salmonella Serotypes Isolated from Children with Diarrhoea in Zliten (2000-2001) • S. Heidelberg • S. Enteritidis

  30. Reistance of Salmonella species isolated from children with diarrhoea in Zliten (2000-2001) to antibiotics ________________________________________________ Antibiotic No. (%) resistant: (n=23) --------------------------------------------------------------------------------- Ampicillin 23 (100) Amoxicillin+calvulanic acid 22 (95.7) Cefoxitin 20 (87) Gentamicin 18 (78.3) Doxycycline 21 (91.3) Chloramphenicol 22 (95.7) Nalidixic acid 1 (4.3) Norfloxacin 0 (0.0) Trimethoprim-sulphamehtoxazole 1 (4.3) ________________________________________________

  31. Department e-mail = dmi.ly • Khalifa Sifaw Ghenghesh e-mail = ghenghesh_micro@yahoo.com

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