Lab 2 Flashcards
(51 cards)
What is the staining of gram +
Fixed smear = colorless
Crystal violet, lugol, alcohol and fuchsin give purple/blue stain
What is the staining of gram -
Fixed smear = colorless
Crystal violet, lugol and give purple/blue stain
fuchsin gives red/pink
Alcohol works as a decolorizer on gram- only, colorless
Zieh-Neelsen staining + gives what staining
Fixed smear=colorless
Carbol-fuchsin, acid/alcohol and nethylene blue gives red
Zieh-Neelsen staining -gives what staining
Fixed smear=colorless
Carbol-fuchsin gives red, acid/alcohol give colorless and methylene blue gives blue
Bacillus - general
Habitat and staining
environment, soil, widely, mineralisation
Gram+
Bacillus - general
Propegation
Spore producing on air and propegation in air -> aerobic
Culture needs Bacillus - general
Obligate aerobic or faculative anaerobic
Bacillus - general
Motility and pathogenicity
Motile, most are saprophytes
B. Anthracis
Habitat and morphology
Animals, environment - eg. Spores can be found in soil after death of animal with pathogen inside
Large with a central spore
B. Anthracis pathogenicity
Obligate pathogen, kills within days (small ru mainly)
B. Anthracis staining
Gram+
Toluieine-blue give blue chains with pink capsule - two colors, metachromatic staining
Spores remain colorless bc wall
B. Anthracis culture needs
Obligate aerobic
nutrient agar, nutrient broth, blood agar is best(but cannot show haemolysis here!)
B. Anthracis colony type, why
Both r and s typendepending on the capsule. 5-10% is needed for capsule production, the capsule give S colonies, R if not enough CO2
B. Anthracis virulence
If there are enough co2 , a cspsule will be produced, which is a plasmid encoded capsule
Poly-D-glutamic acid is a virulence factor which inhibits phagocytosis by neg charge
Spore production of B. Anthracis
Min. (12)15•C, water and O2 (and cations) ae needed - eg wont be enough ox inside carcass for spore prod, must open carcass
Biochemistry of B. Anthracis
Active metabolism, catalase+ and oxidase-
Serotyping of B. Anthracis
The antigen structure is uniform - cannot be used for identification
Polysaccharide hapten of cell wall give immune response if bound, and can be used for identification eg. Ascoli test can be used, but there can be a false oos as it forms cross reaction with b. Cereus
Toxins of b. Anthracis
Found in cell wall, there are three parts: • oedema factor (plasmid coded) • lethal factor (plasmid coded)
• protective antigen
The PA must be bound for the other enzyme componants(oedema and lethql factor) to give their symptoms
Who are affected by b. Anthracis
Bees are totally resistant be they have high body temp, spore loose virulence at 41-42 degrees c
Dogs, pigs, ppl and horse it is usually less acute but still potentially fatal
B. Anthracis pathogenicity
Obligate pathogenic in ru mostly
What differentiates b. Anthracis from the othe bacillus spp?
All species except B. anthracis are motile and saprophytes
B. Cereus is hemolytic on blood agar.
B. Cereus and anthracis need co2 for casule production
General clostridium- motility, staining, catalase, oxidase and envirement requirements, spore
Motile with no capsule except c. Perfringens
anaerobic spore forming, gram +, catalase and oxidase -
Habitat pf clostridium generalspp
Soil, mud water, gut in humans (to environment by faeces)
Culture clostridium
Blood agar is needed but they survive in nutrient agar.
Obligate anaerobic though the ox tolerence differs btw spp.
Most like 37•c, but perfringens like 40-45 and putrefaciens 15-22•c
