Bacillaceae Flashcards
Special staining method for Bacillus
Wirtz-Conclin (spores)
Giemsa-Romanovsky for capsule
Patogenicity of Bacillus
Most are saprophytes with no pathogenic potential
Produce highly resistant endospore
Most important pathogenin bacillus for animal and man
Bacillus anthracis
Pathogenic Bacillus for insects (4)
Bacillus thuringiensis
Bacillus pupillae
Bacillus larvae
Bacillus alvei
Tyzzer’s disease in rodents is caused by
Bacillus piliformis
Which Bacillus are facultative pathogens?
Bacillus cereus
Bacillus subtilis
Bacillus licheniformis
Which applications are Bacillus produced for?
Medical
Agricultural
Pharmaceutical
Enzymes, antibiotics and other metabolites
Which antibiotics may be produced by Bacillus?
Bacitracin (Bacillus licheniformis and bacillus subtilis)
Polymyxin (Bacillus polymyxa)
Gramicidin (Bacillus brevis)
What does Bacillus Anthracis cause and in which animals?
Fatal peracute or acute septicaemic antrax in cattle and sheep
What does Bacillus larvae cause and in which species?
American foulbrood in bees
What is an endospore?
Endospore is a resistant structure formed by Gram + bacteria (in dormant stage)
What is the function of the endospore?
Ensure survival of bacterium through periods of environmental stress.
What causes antrax?
Bacillus anthracis
Virulent strain of Bacillus
Bac. anthracis.
Capsule composed of poly-D-glutamic acid and plasmid-encoded tripartite protein toxin
The tripartite protein toxin in Bac. anthracis consists of?
3 antigen components:
Factor I - oedema
Factor II - protective and
Factor III - lethal
They act synergistically
What forms of antrax is known in man? (3)
Cutaneus form
Pulmonary form
Gastrointestinal form
Characterize Bacillus Cereus
Saprophyte
Facultative pathogen
Cause: septicaemia, meningitis, respiratory tract infections, myonecrosis and food poisoning.
TL toxin –> diarrheal syndrome (meat, milk products, cereals)
TS toxin –> emetic syndrome (cooked or boiled rice)
Characterize Bacillus Thuringiensis
Pathogen of larvae - crop protection against harmful insects
Produce protein crystals (protoxin) - delta-endotoxin.
Used in commercial insecticides.
Microscopical examination of Bacillus
Gram +
Motile (except Bac. Anthracis)
Large rods
Cells occur singly in pairs or long chains
Bac. Anthracis and Bac. Cereus growth under aerophilic conditions
R form
Bac. anthracis - no capsule - weak virulence
Bac. Anthracis under microaerophilic conditions
S form
Capsule
Fully virulent
Cultivation properties of Bacillus
Aerobic or microaerophilic
37 degrees C (10-45C, 25-40C for pathogenic)
24-48 hours
Bacillus on meat-peptone-broth
Sediment
Bacillus on meat-peptone-agar (7)
R form
Large
Flat, dry
Greyish colonies
Curled outgrowths (Medusa’s head)
Bacillus on blood agar
R form
B. anthracis - no haemolysis
B. cereus - b-hemolysis
Special agar for Bacillus
Nutrient agar with 0.7% NaHCO3.
In microaerophilic conditions bacillus anthracis grows in S/M form and produce a capsule
Bacillus reaction for catalase and oxidase
Catalase +, oxidase -
Lectinase activity of bacillus on egg yolk agar
Bac. anthracis - weak opaque zone
Bac. cereus - strong
Bacillus reaction on gelatine
Bac. anthracis - inverted
Others - strong
Serology of Bacillus (3)
Somatic O antigen
Capsular K antigen
Anthrax toxin - protective antigen
Which special reaction is for Bac. anthracis?
Ascoli’s thermoprecipitation reaction - antiserum against Bac. anthracis
Special examination methods for Bacillus
Susceptibility to penicillin (Bac. anthracis is sensitive)
Jensen-Kleenmayer’s test (pearl test, Bac. anthracis on blood agar with PNC –> looses cell wall –> protoplast arranged in chains)
DNA methods
Characterize Bacillus Anthracis
Non-motile
No haemolysis
Sensitive to penicillin
Weak and slow lectinase activity on egg yolk
Lysis on gamma phage
Causes death within 24-48 hours
Capsule +
Ascoli reaction +
Pearl test +
Characterize Bacillus Cereus
Motile
Haemolysis
Resistant to penicillin
Strong and rapid lecithinase activity on egg yolk
Lysis on gamma phage is rare
No effect on animals
Capsule -
Ascoli -
Pearl test -
