Bacillus and Aerobic spore forming bacteria Flashcards
Gram-staining color: fixed smear
Gram + : colourless
Gram - : colourless
Gram-staining color: Crystal violet (primary stain)
Gram + : blue
Gram - : blue
Gram-staining color: Lugol-solution (mordant)
Gram + : blue
Gram - : blue
Gram-staining color: Alcohol (decolorizer)
Gram + : blue
Gram - : colourless (because thin layer PG)
Gram-staining color: Fuchsin (counterstainer)
Gram + : blue
Gram - : red
Aerobic or anaerobic?
Can propagate in air, aerobic and facultative anaerobic
Spores?
yes, endospores are produced
Important species?
B. Anthracis
Catalase, oxidase?
Catalase +
Oxidase -
Motility?
Flagella, except B. Anthracis
Habitat
- Environment (spore), soil, mineralization
- Animals (vegeative) and mainly small Ru,
Morphology
- 4-5 um
- Rod
- Capsule
- Square ended, relatively short (can be longer in culture)
- Spore is colourless, wall has special structure
- Chain formation
Staining
- Gram positive
- Toluidine blue (metachromatic staining -> capsule-pink, bacteria-blue)
Culture (B. Anthracis)
- Simple, nutrient agar, nutrient broth or blood agar with air and 37 degrees
- Obligate aerobic
Culture (B. Anthracis), Colony types:
- R = rough; mat, uneven edge, rough surface
- S = smooth; bright, entire edge, smooth surface capsule
Culture (B. Anthracis), Capsule
- Poly-D-Glutamic acid polypeptide capsule
- Virulence factor (inhibits phagocytosis, plasmid encoded, extra chromosome)
- 5-10% CO2 is needed for the production
Culture (B. Anthracis), Spore
- Cations are needed
- Minimum 12-15 C
- Water
- O2 -> cant form spores inside carcass, so dont open carcass
- Time needed:
37 C -> finished within 16 hours
18 C -> starts after 50 hours, 2-3 days are needed
Biochemistry
- Active metabolism
Antigens
- Uniform antigen structure
- Capsule (virulence factor); D-glu-polypeptide, saprophytes also produce
- Polysaccharide hapten; detect in lab test, Ascoli test (serological test), cross reactions with B. Cereus (can cause false positive test)
- Toxin; oedema factor (plasmid coded), lethal factor (plasmid coded), protective antigen
Resistance
- Severeal days in carcass, skin:2 weeks, bone marrow:4 weeks, 56 C:15 min - dead
- Vegetative bacterium: medium
- Spore: decades, for more than 50 years
- Boiling: 5-10 min
- Formalin 8-10%: 12-24 hours
Pathogenicity
- Obligate pathogenic
- Virulence factors (capsule, toxin)
- Mammals (mainly herbivores), birds are less susceptible (lacks the plasmids coding, high body temp)
- sheep (septicaemia), cattle, goat, horse (oedema, colic, enteritis), dog (comparative resistant, carnivores), swine (oedema in pharyngeal region), human (skin, pulmonary, hemorrhagic pneumonia, intestinal)
Pathogenicity; species
- Mammals (mainly herbivores), birds are less susceptible (lacks the plasmids coding, high body temp)
- sheep (septicaemia)
- cattle (enlargement of spleen)
- goat
- horse (oedema, colic, enteritis)
- dog (comparative resistant, carnivores)
- swine (oedema in pharyngeal region)
- human (skin, pulmonary, hemorrhagic pneumonia, intestinal)
Saprophyte Bacilli species
B. subtilis B. megaterium B. cereus B. licheniformis B. thuringiensis
B. Cereus
Hemolysis, S-type colony, can move under microscope, foodpoisoning, diarrhea - gastrointestinal infection
B. Licheniformis
Bacitracin, sometimes abortion (cattle, sheep)
B. Thuringiensis
Insect pathogen, pest control
Differentation of the most important Bacillus species; flagella
B. Anthracis: no
B. Subtilis: yes
B. Megaterium: yes
B. Cereus: yes
Differentation of the most important Bacillus species; capsule (air)
B. Anthracis: no
B. Subtilis: yes
B. Megaterium: yes
B. Cereus: no
Differentation of the most important Bacillus species; haemolysis
B. Anthracis: no
B. Subtilis: no
B. Megaterium: no
B. Cereus: yes
Differentation of the most important Bacillus species; pathogenicity
B. Anthracis: yes
B. Subtilis: no
B. Megaterium: no
B. Cereus: no
Paenibacillus:
- Paenibacillus (Bacillus) polymyxa: produces polymyxins
- Paenibacillus (Bacillus) larvae: American foul brood of honey bees. Gram+, rod shaped, sporeforming -> burn the hives (yellowish mucous in hives, notifiable disease)
Geobacillus:
- Geobacillus (Bacillus) stearothermophilus: heat resistant, test organism (food bacteriology)