BACILLUS Flashcards
Almost all of Genus Bacillus are non-pathogenic and saprophytic. True or False?
True
What is the most pathogenic species of Bacillus?
B. anthracis
What is the German name of anthrax?
Milzbrand
What is French name of anthrax?
Charbon
Carnivores and birds are highly susceptible to B. anthracis while herbivores are resistant, True or False?
False, other way around
Is anthrax fatal in humans?
Yes
Give the morphology of Bacillus anthracis.
Large, Gram (+) rods, 1 um x 3-6 um
What is the form of Bacillus anthracis when in cultures?
Forms long chains which appear as solid filaments because of square ends that fit closely together
What is the form of Bacillus anthracis when in tissues?
Short chains with ends of cells rounded
What temperature does the spores of Bacillus appear? And in what presence does it occur?
15-40 C, in the presence of air
Give the morphology of spores of Bacillus anthracis.
Spores central to subterminal and not swollen
Bacillus anthracis doesn’t grow well on most lab media. True or False?
False
On what temperature and duration does the spores of B. anthracis germinate?
65 C for 15 mins.
What is the appearance of B. anthracis when inoculated on agar?
Ground glass-like appearance on surface colonies on agar with irregular margins
Under LPO, what is the appearance of B. anthracis on agar?
Resembles locks of wavy hair known as Medusa-head colonies
Biochemically, B. anthracis is much less active than other bacilli. True or False?
True
B. anthracis is non-motile. True or False?
True
Give the composition of capsule of B. anthracis.
Made up of polymers of D-glutamic acid and some polysaccharide
Spores of B. anthracis are killed by either boiling or autoclaving. True or False?
False, spores are resistant to boiling; killed only by autoclaving
B. anthracis can be killed by disinfectants. True or False?
False, they are resistant and remain viable for more than 50 years
The vegetative cells of B. anthracis can be killed at what temperature and what duration?
60 C for 30 mins
Give the major anthrax enzootic zones. (tropical and subtropical places)
- India
- Pakistan
- Africa
- South America
Give the pathogenesis factors on why tropics and subtropics country are considered the habitat of B. anthracis.
- Alkaline soil with high nitrogen level caused by decaying vegetation
- Alternating period of rain and drought
- Temperatures beyond 5.5 C
Give the source of infection of anthrax.
- Soil
- Bone meal
- Vegetable protein
- Tannery effluents
- Bloodsucking flies and carrion eaters
What is the threshold for the death of animal infected with anthrax?
If splenic clearance exceeded, animal dies -> 80% of organisms in
blood, 20% in spleen
What is the name of the toxin complex of B. anthracis?
Holotoxin
Give the three components of holotoxin of B. anthracis.
- Edema factor (EF)
- Protective antigen (PA)
- Lethal factor (LF)
Give the principle and mode of action of Edema factor (EF) of holotoxin of B. anthracis.
Edema factor acts as adenylate cyclase which increases intracellular cyclic AMP
Give the principle and mode of action of protective antigen (PA) of holotoxin of B. anthracis.
Plasma-encoded, necessary for biological activity of EF and LF; probably a receptor-binding molecule
Give the 4 net effects of holotoxin.
- Damage and kill phagocytes
- Increased capillary cell permeability
- Damage clotting mechanism
- Inhibit bactericidal activity of serum
Give the sequential events when anthrax induce capillary thrombosis.
Capillary thrombosis -> fluid leaks thru damaged endothelium -> blood
pressure falls -> shock
One effect of holotoxin is that it blocks opsonizing activity of specific factor of complement mechanism. Give the factor and effect when it is blocked.
C3 factor; reduced phagocytosis
Give some of the symptoms of anthrax.
- Edema
- Shock
- Hemorrhaging before death (peracute form 1-2 hours, acute form less than 24 hours)
What is the portal of entry when a localized anthrax is present?
Thru wound on skin; cutaneous form; malignant carbuncle or pustule
Localized anthrax is more often in animals than in humans. True or False?
False, other way around
Localized anthrax can turn into a generalized form. True or False?
True
Give the sequential events when localized form of anthrax with pharyngeal involvement and gastroentiritis occured in swine and dogs.
Localized form with pharyngeal involvement and gastroenteritis -> inflammatory edema of head and neck -> suffocation
What is the portal entry when generalized anthrax is present?
Airborne spores; pulmonary or inhalation
anthrax (Woolsorter’s disease)
One diagnosis of B. anthracis infection is to release minimum number of anthrax organisms in the environment. True or False?
True, e.g. blood samples from ear veins
Diagnosis of B. anthracis: Give the principle of Mc Fadyean’s stain.
Organisms blue, capsules pink
Diagnosis of B. anthracis: Give the principle of AGPT (Agar gel precipitation test)/Ascoli Test
Detection of capsular antigen
Diagnosis of B. anthracis: Give the principle of blood agar plate inoculation.
Ground glass-like non-hemolytic colonies on BAP -> Medusa-head or
judge’s wig-type colonies
Diagnosis of B. anthracis: Give the principle of String of pearl test.
In presence of penicillin, organisms grow with cell
wall impairment -> organisms resemble string of pearls
Diagnosis of B. anthracis: Give the principle of Bacteriophage (gamma phage).
Only B. anthracis is lysed
Diagnosis of B. anthracis: Animal test is pathogenic to what animal? And how many hours does it take for animals to die?
Guinea pigs, mice; death within 24 hrs
Recovered animals from B. anthracis infection have permanent immunity. True or False?
True
What are the forms of immunization against B. anthracis?
- Sternes’ live (non-capsulated)
- Avirulent spore vaccine or culture filtrate of avirulent (non-capsulated strain)
Give ways on how to prevent and control B. anthracis.
- Reportable disease
- Should be treated, uninfected animals immunized
