5. General characterisation of Enterobacteriaceae. Escherichia, Klebsiella, Enterobacter. Flashcards
Enterobacteriaceae:
- Habitat
- Morphology
- Staining
- Habitat : gut, mucous membrane, normal gut flora, environment
- Morphology: 1-3 microrod flagella
- Staining: gram -
Eneterobacteriaceae:
Culture
Simple:
Aerobic, facultative anaerobic
Degrees :
- Selective and differrentiated media - isolated from mixed culture
- Chromogenic media - detection of specific enzymes
Selective enrichment:
-Isolation of salmonella
Combined media:
-Examination of more characteristics in one media
Selective and differentiated media
Low selectivity capacity;
- Enterobateria, all kinds
- Bacteria of some gram - genera
- Gram positive bacteria cannot be cultured
- Crystal violet - lactose-litmus
- Crystal violet - bile salt-lactose (acid production) - neutral red
- Eosin- lactose-methylene blue- Na-lauryl sulphate
Medium selective capacity:
- some genera of enterobacteriaceae
- brilliant green: inhibitory, isolation, salmonella, most important antibacteristisca
- dc medium is used for isolation of ischella?
- XLD: mainly used for E.coli
High selective capacity:
- salmonella : wide range of diseases, zoonotic
- bismuth: highly selective,only salmonella can grow in it, reduces the bismuth
Chromogenic media:
- Single enzyme is used
- Rambach agar - detectsenzyme which are usedfor decomposiation of glycon
- Mixed culture there will be red colonies hich are red
- CCA agar- two enzymes galactosidase, gluconidase
Eneterobacteriaceae: Biochemistry
Differentiate the generea:
catalase +
oxidase -
Fermentative acid + gas
- carbohydrate production
- uniqe characteristic
Eneterobacteriaceae: Antigens
4 types:
- serotyping
- pathogenecic : virulence factors as well
O: cell wall
K: kapsule - polysaccharide
H: flagella
F: fimbria
-pathogenecis
-virulence factor
Enterobacteriaceae: Resistance
Medium, does not form spores
Enterobacteriaceae: Pathogenecity
- Saprophytes - do not cause disease - harmless
- normal gut flora
pathogenic:
- facultative pathogneic
- obligate pathogenic
Enterobacteriaceae: Grouping
Genus - biochemical characteristics
Species:
- biochemical and serological characteristict
- antigenic structures
Serogroups:
- of the cell wall antigen O antigen
- secondary differentiating
Serotype :
O-K-H-F
Most important genera of the family Enterobacteria
Lactose poitive:
- escherichia
- klebsiella
- enterobacteria
Lactose negative:
- salmonella
- shigella
- yersinia
- proteus
- providencia
- edwardsiella
- serratia
- citrobacter - saprohyte, similar to salmonella
Klebsiella: (K.Pneumoniae)
- Habitat
- Morphology
- Culture
1.Habitat - Gut, respiratory way, genital tract, environment
2.Morphology - Rod, Capsule (thick), No flagellum
3.Culture - Large, merging mucoid colonies, Rapid change of the color of the indicator.
Escherichia:
- Habitat
- Morphology
- Staining
- Habitat:
- Gut
- Aerobic
- Facultative anaerobic gut
- Flora
- Shed with faeces - Morphology:
- 2-3 micrometre rods
- Capsule
- Flagella
- Fimbria - virulence
- Factor : attach to target cell, direct contact
3.Staining:
Culture of escherichia:
Simple, not fastidious :
-following the general principles of enterobacteria
Selective and differentiated media:
- Low selective capacity and on medum selective capacity medium
- Lactose positive - acidic pH will be shown
Capsule:
-e.coli strains from calf
Haemolysis:
- Some strains
- E.coli strains fro swine
Brilliant green - not green
- orange color is normal
- very much diluted
Biochemistry of escherichia:
Lactose +
Indol +
Antigens of escherichia:
O: type specific
K: polysaccharide
F: 30 types
F1: common fimbria
F2,F3: human
F4,F6,F18 ab/ac: swine
F5, F17,F41: cattle
F7-F16:UTI, human poultry
H: 53types
Resistance of escherichia:
Medium, not spore forming
Pathogenecity of escherichia:
Saprophytes :
- Normal gut flora
- Normal flora of mucous membranes
Facultative pathogenic :
Cattle :
-Calf cloi-diarrhea - neonatal
-Calf coli-septicaemia
-Cow:mastitis
Swine:
- Coli-diarrhea of neonatal pigslet
- Weaned piglets: coli diarrhea
- Weaned piglets: oedema disease
- Sow: mastitis, metritis
Sheep, goat
Rabbit:
-Diarrhea
Poultry:
- Septicaemia: day old chicken
- Septicaemia, respiratory disease: adult chicken
- Adult: lesions in organs
- -Airsacculitis, peritonitis, coli granulomatosis
Foal, dog, cat, minkk, fox, nutria, chinchilla:
- Coli-diarrhea
- Septicaemia
Human:
- Neonatal enteritis, septicaemia
- Urogenital infections
- Enteritis
Genetic variety
Groups of pathogenic E.coli strains
Enteropathogenic strains
Enterotoxigenic strains
Verotoxigenic strains
Necrotoxigenic strains
Enteroinvaive strains
Nteroadhesive-aggregative strains
Septicaemia
Virulence factors of pathogenic E.coli:
Enterotoxigenic:
- Adhesins - attach
- Enterotoxins: result in disease
- -ST - heat labile
- -ST - heat stabile
- -Excrete water into the gut - dirrhea, damage of fluid absorption
Verotoxigenic:
- Verotoxins
- Vero=monkey, cell lne, detcted for the first time
- Inhibit protein synthesis
- Endotheelial cellsare susceptible
- Edema, hemorrhages
Necrotoxic
Enteroinvasive:
-Diarhea
Enteroadhesive:
-Diarrhea
Septicaemiac strain:
- Invasive capacity, virulnece factor
- Survive in the blood
Enterobacteria:
- Habitat
- Morphology
- Habitat: gut, environment
- Morphology:
- Rod
- Capsule: strong and large , not as large as klabsiella
Enterobacteria:
- Culture
- Biochemistry
- Pathogenicity
- Species
- Culture
- Mucoid
- Colonies - Biochemistry
- Lactose +
- Voges-proskauer test - Pathogenicity
- Saprophytic
- Rarely respiratory infection in humans
4.Species
- E.Cloacae
- E.aerogens
