5th Test - General characterisation of Enterobacteriaceae. Escherichia, Klebsiella, Enterobacter. Flashcards
Enterobacteria can be found in the gastrointestinal tract only?
False
also in genital tract, respiratory tract and in the environment
Enterobacteria are middle-sized Gram-positive rods?
False, gram negative
Enterobacteria are obligate anaerobic bacteria?
False, (they are aerobic, facultative anaerobic)
Enterobacteriaceae are oxidase-negative bacteria?
True
Shigella species are motile bacteria?
False, not motile
MacConkey agar contains phenol red as a pH indicator?
False, contains Drigalski agar (neutral red)
MacConkey agar contains glucose as a carbon source?
False, lactose
Pathogenic E. coli strains isolated from the gut of piglets possess F5, F17 or F41 fimbrial antigens?
False
(F4, F6, F18=swine,
F5, F17, F41 = cattle)
E. coli can cause septicaemia in calves?
True
Klebsiella species are lactose-negative bacteria?
False, they are lactose-positive
Enterobacteriaceae are Gram-negative bacteria?
True
Klebsiella pneumonia is flagellated?
False, no flagella
Bismuth-sulphite agar is used to isolate E. coli?
False, used to isolate salmonella
E. coli strains can form capsules which were isolated from swine?
False, in calf (swine: haemolysis)
Enterobacteria are fastidious bacteria?
False (simple)
Oedema-disease is caused by E. coli in neonatal piglets?
False, in weaned piglets
Klebsiella pneumonia cannot produce a capsule?
False, has capsule
Enterobacter cloacae are a lactose-negative bacteria?
False, lactose positive
E. coli is an obligate pathogenic species?
False (most of them are saprophytic, some are facultative pathogenic
E. coli is an indole-positive bacteria?
True
Normal habitat of Enterobacteriaceae
Gut - Feces to the environment
- Most are Saprophytes
= inhibits growth of unwanted pathogen - Produce Vitamins
- Help in digestion
- Some contain enzymes (host has not)
Morphology of Enterobacteriaceae
Mid sized (1-3 micrometer)
ROD
FLAGELLA
(not shigella and Klebsiella)
Some have CAPSULE and FINBRIA
Morphology of Enterobacteriaceae
RESISTANCE
Fair, average resistance
Only Enterobacteriaceae has lactose + bacterias
- Lactose test will give you only 3 bacterias left
Which
E-Coli
Klebsiella
Enterobacter
Enterobacteriaceae
Staining
GRAM NEGATIVE
Enterobacteriaceae
Culture
SIMPLE AEROBIC FACULATIVE ANAEROBE 10-45 degrees (37 degrees) Wide temperature range wher proppagation is possible
Enterobacteriaceae
Culture
How long time to produce colony?
1 day
Enterobacteriaceae
Selective and Differential media
- Offen contain manny bacteria!!!!
Differentation is maily due to LACTOSE Fermentation
Enterobacteriaceae
Selective ENRICHMENT
- Salmonella - Combined media, can examine many features of bacteria at the same time
- Mainly used in food hygiene, not in clinical diagnostics - Chromogene Media, media containing chemicals. = When a reaction occurs it changes color.
Enterobacteriaceae
Selective ENRICHMENT
Chromogene Media
- RAMBACH AGAR
= Fermentation of propylene glycol - TURNS PINK…. - GLYCOL - same but for SALMONELLA
- Chromocult coliform agar
= differentiate btw E.COLI and COLIFORM
Enterobacteriaceae
Media contain
All media contains:
- LACTOSE,
- INDICATOR and
- INHIBITORY MATERIALS