ENTEROBACTERIACEAE Prof. Khalifa Sifaw Ghenghesh.
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Transcript of ENTEROBACTERIACEAE Prof. Khalifa Sifaw Ghenghesh.
• Gastrointestinal diseases(Diarrhoea and Dysentery)
– Escherichia coli (Lac+)– Salmonella (Lac-)– Shigella (Lac-)– Yersinia entercolitica (Lac-)
• Opportunistic diseases– septicemia, – pneumonia, – meningitis– urinary tract infections
• Citrobacter• Enterobacter• Escherichia• Hafnia• Klebsiella• Morganella• Proteus• Providencia• Serratia
IDENTIFICATIONIDENTIFICATION
• In Stool:– E. coli
• lactose positive • not usually identified• Common in healthy intestine
– Shigella, Salmonella,Yersinia• lactose negative• identified
• Other sites:Other sites:– identified biochemicallyidentified biochemically
SEROTYPINGSEROTYPING
• Reference laboratory:– antigens
• O (lipopolysaccharide) • H (flagellar) • K (capsular)
• 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
• 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
• 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)
TREATMENTTREATMENT
• Gastrointestinal disease:Gastrointestinal disease:– Fluid replacement– Antibiotics
• not used usually unless systemic
–e.g. hemolytic-uremia syndrome
• UTIs:– Antibiotic Sensitivity Is Necessary.
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 *(%)
-------------------------------------------------------------------------------------
• 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.
• The Organism Survivethe 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.
• Man only "reservoir"
• Mostly young children
– fecal to oral contact
– children to adults
• Transmitted by adult food handlers
– unwashed hands
Treating Shigellosis
• Manage dehydration
• Patients respond to antibiotics– disease duration diminished
CONTROL
– Adequate Sanitization.– Detection and Treatment of Carriers.– Carriers Should Not Be Allowed to Handle
Food.– Proper Sewage Disposal and Chlorination
of Water.– FLIES >>>>>>>>>>>>>>>>
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. sonnei2. F 30 Sep 2 3 S. flexneri type2
3. M 27 Oct 1 6 S. sonnei4. 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
Information about Libyan children with diarrhea and their Shigella isolates
Faeces with Presence ofPatient Mucus Blood Fever Vomiting Species and
serotype ofShigella
---------------------------------------------------------------------------------------------------------------------1. + + -- -- S. sonnei2. -- -- -- -- S. flexneri type23. -- -- + -- S. sonnei4. -- -- -- -- S. flexneri type25. + + + -- S. flexneri type26. -- -- + -- S. flexneri type17. + + + + S. flexneri type28. + + + + S. flexneri type39. + + + + S. sonnei
• More than 2000 antigenic types More than 2000 antigenic types (Serotypes).(Serotypes).– Salmonella Typhi– Salm. Enteritidis– Salm. Cholera-suis– Salm. Typhimurium
• Genetically single speciesGenetically single species– Salmonella enterica
• Salm. enterica serotype TyphiANTIGENIC STRUCTURE:
– O & H Antigens >>> Serotyping.– Vi-Antigen (protective) >>> Salm. Typhi.
CLINICAL INFECTION AND PATHOGENSISCLINICAL 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:
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:
• 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.
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
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-sulphamehtoxazole1 (4.3) ________________________________________________