enterobacteriaceae (e.coli & klebsiella pneumoniae)
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Enterobacteriaceae
Dr.Aravind
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Gram Negative Enteric Rods
Routinely Found In The Gastrointestinal Tract
Facultative Anaerobes Lipopolysaccharide (LPS): Antigenic & Endotoxin
Belong To Diverse Taxonomic Groups
Cause Diseases In The GI Tract, Outside The GI Tract, Or In
Locations.
Oxidase Negative
Non Spore-forming
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Enterobacteriaceae
Classification
Lactose fermenters
Escherichia Coli
(Motile)
Klebsella Pneumonia
(Non motile)
NonLactose F
Salmonella
Proteus
Motile and H2S producing No
No
pro
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Escherichia Coli(E.coli)
Dr.Aravind
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Gamma Proteobacteria
Order: Enterobacteriales
Family: Enterobacteriaceae
Genus: Escherichia
Species: E. coli
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Gram Negative rod
Facultative anaerobic
Bacteroides species : E. coli = 20:1
O, H, and K antigens = 700 serotypes
Oxidase (-), Catalase (+)
Ferment glucose, Lactose, and can generate energy by reduc
nitrates to nitrites
MacConkey Agar- pink colonies
EMB - metallic shine appearance on colonies
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Virulent Factors P Pili (Pyelonephritis-associated Pili):
Binds To Galactose Dissaccharide Of UT Epithelium Most Imp In UTI
Type I Pili: Bind To The D-mannose Receptors On Epithelial Cell Surfa
CFA Or BFA: Bind To Enterocytes
Non Fimbrial Adhesin (Intimin)
Siderophores E.Co
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Capsule (K Antigens) :
K1 Capsule In Neonatal Meningitis
Antibodies And Complement Bacterial Surface, Phagocytosis
O Antigen : Outermembrane
Endotoxin
H Antigen: Flagella
Motility And Invasive Disease
Alpha-hemolysins Pore formation on membrane, toxic to many mammalian cells.
Lyse Lymphocytes, Beta-hemolysins, Inhibit Phagocytosis And ChOf Neutrophils
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Exotoxins:
Heat-labile Enterotoxin (LT)
Similar Function To The Cholera Toxin
Binds Identical Ganglioside Receptors On Enterocytes Heat Stable Toxin (ST)
Binding To Guanylate Cyclase Receptors On The Apical MemHost Cells, Thereby Activating The Enzyme Diarrhea.
Resistant to boiling 300C
Shiga toxins (verotoxin) protein synthesis by destructing 28S ribosome
HUS syndrome
O157:H7 serotype
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Epidemiology
Human Bowel Is Usually Colonized Within 40 Hours Of Birth.
700 Serotypes Of E. Coli Based On O, H, And K Antigens
Bacteroides Species : E. Coli = 20:1
Most Common Cause Of UTI
2rd Most Common Cause Neonatal Meningitis
A Leading Cause Of Infantile Diarrhea In Developing Countries
Transmission: UTI - intestinal E. coli perineal Urethra
Neonatal MeningitisBirth Canal
Intestinal diseasecontaminated Food or water
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Pathogenic e.coli
Extra intestinal diseases
UTI
Neonatal meningitis
Pneumonia
Septicemia
Intestinal diseases
E.coli Strains
ETEC
EPEC
EIEC
EAEC
EHEC
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E.Coli UTI Pathogenesis
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Courtesy from Sherries
MicrobiologyDr.Aravind
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Intestinal E.coli Pathogenesis
Virulent factors
CFA
LT
ST
Virulent factors
Outer
Membrane
Proteins
Virulent factors
BFA,
Intimin
ESPS
Virulent factors
Intimin
Shiga like toxin
Vi
ST
he
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Cli i l diti
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Clinical conditions
Extra intestinal infections
Urinary Tract Infection: Uropathogenic E. Coli (UPEC) Cause 90% Of The UTI
pregnancy
Dysuria, Lower Abdominal Pain, Increase Discharges
Cystitis, Increased Frequency Of Urination, Dyspareunia
Pyelonephritis:
Fever, Dysuria, Radiating Back Pain, Tenderness At The Vertebral Angle, Shock.
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Neonatal meningitis:
2 nd most common
Transmission - Birth canal
Virulent factorK1 capsular antigen
Fever, irritability, constipation, poor feeding, bulging fronseizures
Neonatal Pneumonia:
Birth canal Respiratory symptoms
Septicemia
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Intestinal DiseasesEnterotoxigenic E. Coli (ETEC):
Infants And Travelers To Underdeveloped Countries Or RPoor Sanitation
In U.S Outbreaks By Water, Soft Cheeses, Mexican-styleAnd Raw Vegetables
Infective Dose 108
Onset In 12 Days
Virulent Factors:
CFA, LT And ST Watery Diarrhea Similar To Cholera Syndrome
Non Inflammatory, Non Invasive
Adults in endemic areas evidently develop immunity Self limiting
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Enteroinvasive E. Coli (EIEC): Similar To Shigella Dysentery
Under 5 Years Of Age
Oro fecal route
Lack Fimbriae Adhesins And LT And ST (has Outer Membrane Pr Inflammatory And Invasive
dysentery-like diarrhea (mucous, blood), severe inflammation, feve
Enteroaggregative E. coli (EAEC):
persistent diarrhea in young children Non inflammatory, non invasive
ST toxin and hemolysin
Biofilm
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Enteropathogenic E. Coli (EPEC)
20% Of Diarrhea In Bottle-fed Infants < 1 Year
Transmission: Fomites, Drinking Water ,Meat Products
Day cares and hospitals
Infecting Dose For Infants Is Low
Virulent Factors: Intimin,
E. Coli Secretion Proteins (Esps),
Tir (Translocated Intimin Receptor)
A/E Lesions
Symptoms: Watery Diarrhea
Enteropatho
(EPEC) attac
cells. The EP
and effacing
epithelial ce
filamentous
the attachm
Dr.Aravind
C h i
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EPEC Pathogenesis
Courtesy by CrDr.Aravind
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Enterohemorrhagic E. Coli (EHEC): Hemorrhagic Colitis (HC) Or Bloody Diarrhea
Serotype O157:H7
Reservoir are Infected Cattle, Beef Products, Lettuce, Sprouts, Fruit, Fruit JuUnpasteurized Milk.
Low Infectious Dose 10 - 100 Organisms.
Virulent factors: Intimin Shiga like toxin or Vero toxin
Symptoms: Watery Diarrhea ,Severe Cramps And Progresses To Bloody Diarrhea. Fever Is Low Grade Or Absent
Complication: Hemolytic-uremic Syndrome (HUS) Thrombotic Thrombocytopenic Purpura, Renal Failure And Microangiopathic Hemo HUS Ensues In Approximately 5% To 10% Antibiotics may induce Shiga toxin.
Dr.Aravind
EHEC P th i
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Courtesy
EHEC Pathogenesis
Dr.Aravind
Diagnosis
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Diagnosis
Extra intestinal Infections: Specimens - bladder or CSF
Culture on MacConkey agar (pink colonies)
Serological tests
Intestinal infections: Culture on MacConkey agar ( Pink colonies)
EMB agar
EHECMacConkey sorbitol agar - No growth
Oxidase Negative
Leukocyte esterase positive
Nitrates to nitrites
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Treatment
Extra Intestinal Infections:
UTI: Ciprofloxacin, Trimethoprim, Sulfamethoxazole.
Meningitis: Cefalosporins
Intestinal Infections:
Rehydration And Supportive Measures
Trimethoprim/SulfamethoxazoleETEC, EPEC And EIEC.EHEC:
Hemodialysis Or Hemapheresis
No Anti Motility Drugs
Dr.Aravind
Ki d B i
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Klebsiella Pneumoniae
Dr.Aravind
Kingdom:Bacteria
Phylum: Proteobacteria
Class: Gamma Proteobacteria
Order: Enterobacteriales
Family: Enterobacteriaceae
Genus: Klebsiella
Species: K. pneumoniae
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Gram-negative Rod Shaped Bacterium
Non-motile, Oxidase (-)
Lactose Fermenting, Facultative Anaerobic
Found In The Normal Flora Of The Mouth, Skin, And Intestines
Thick Capsule-made Of Polysaccharides Virulent Factors: Capsule & Endotoxin
Susceptible Pts: VAP Hospitals Alcoholics & Diabetics Immuno-compromised Patients & Catheter
Causes Pneumonia, Meningitis And UTI Thickness And Bloody Sputum- B/C Of Thick Capsule
Diagnosis: Culture, Serology
Treatment: Cephalosporin's - Cefotaxime & Fluor quinolones
Dr.Aravind