Gram-Positive Bacilli,Aerobic, Spore-forming, Catalase-Postive, Non-branching Flashcards
The species only form endospores aerobically
Bacillus
The species are motile with peritrichous flagella except for
Bacillus anthracis and Bacillus mycoides
The species can survive in extreme environmental conditions due to their endospores
Bacillus
Microscopy: Large, boxcar-shaped, Gram-positive rods with clear, unstained, central spores or
―”empty spaces”
Bacillus
The most clinicall significant species include:
B. anthracis, B.cereus, B. thuringiensis, and B.
mycoides
Biochemical test: (+) Catalase; ferments glucose; hydrolyzes starch
Bacillus
It is the causative agent of anthrax
Bacillus anthracis (Anthrax Bacillus)
It is not part of the indigenous human microbiota
It can grow aerobically or anaerobically
Bacillus anthracis (Anthrax Bacillus)
It is not highly contagious
Bacillus anthracis (Anthrax Bacillus)
It is non-motile and is considered as a halophilic organism that can withstand up to 7% NaCl
Bacillus anthracis (Anthrax Bacillus)
It can be used as a biological weapon of mass destruction, and therefore a vital concern in the
campaign against global terrorism
Bacillus anthracis (Anthrax Bacillus)
it grows in a low-pH (<6.0) environment, produces lecithinase, and ferments WHAT?
GLUCOSE- Bacillus anthracis
Microscopy: Gram positive, large, encapsulated, and square-ended rod; has a ―”bamboo fishing
rod” appearance on the unstained central spore
Bacillus anthracis (Anthrax Bacillus)
BAP-Colonies have a ―”Medusa head” appearance with swirling projections; are non-hemolytic‘ and gain a ―be
Bacillus anthracis (Anthrax Bacillus)
Growth factor of B. anthracis
Thiamine B1
It gains a ―”string of pearls” appearance when penicillin, to which it is susceptible, is used
Bacillus anthracis
It is a disease that primarily affects animals, such as goats and sheeps, by
feeding on plants that are contaminated with spores
Anthrax
Microscopy: Gram positive, large, encapsulated, and square-ended rod; has a ―bamboo fishing
rod‖ appearance on the unstained central spore
B.anthrax
Three forms of anthrax:
It is characterized by the appearance of a ―”black eschar” which is a black,
necrotic, and painless central area that does not produce pus
Cutaneous anthrax
Three forms of anthrax:
It is acquired through skin cuts and abrasions
A small papule appears at the site of the spore inoculation two to five
days after exposure
Cutaneous anthrax
Pulmonary Anthrax is also known as?
Woolsorter’s Disease
It is acquired when spores are inhaled into the pulmonary parenchyma
It resembles an upper respiratoy tract infection
Signs and symtoms: Mild fever, fatigue, malaise, and dyspnea
Pulmonary anthrax
Spores are inoculated into a lesion on the intestinal mucosa following
their ingestion
Signs and symptom: Abdominal pain, nausea, anorexia, vomiting and
bloody diarrhea
Gastrointestinal anthrax
is typically isolated from normally sterile sites such as blood, lung tissue, and CSF
B. anthracis
Processing of samples for B. anthracis should be done in a biological safety cabinet with
biosafety level 3
Spore stains of B. anthracis
Malachite green and McFadyean stain
Capsule stain of b. antracis
India ink
is recommended for identification of B. anthracis in fecal specimens
Phenylethyl Alcohol Agar
are used in isolating Bacillus species from contaminated specimens
phenylethyl alcohol (PEA), polymyxin-lysozyme-EDTA-thallous acetate (PLET)
is used to determine if the B. anthracis has produced lecithinase, in which case the
medium will have an opaque zone
Egg yolk Agar
What medium is utilized to observe the ―”inverted-pine-tree” of ?
Gelatin medium; Bacillus anthracis
Diagnostic Test for Bacillus anthracis
It detects thermostable anthrax antigens
It uses rabbit antiserum to observe precipitin formation
. Ascoli test (precipitin test)
Differentiates Bacillus species (catalase-positive) from Clostridium species (-)
Catalase Test
Gives variable results
Oxidase Test
Positive cell wall polysaccharide and capsule antigen
Direct fluorescent antibody test
“Fried rice’ bacillus
Bacillus cereus
It causes food poisoning due to the ingestion of contaminated cooked rice dishes (typical
source) or other food products
Bacillus cereus
It is the most commonly encountered Bacillus species in opportunistic infections that causes eye
and ear infections
It exhibits motility and resistance to penicillin
Bacillus cereus
: BAP-colonies are large and feathery; have a spreading growth; have a ―”frosted-glass”
appearance; and are Beta hemolytic
Bacillus cereus
Best specimen for testing Bacillus cereus
Suspected food (greater than or equal 10^5
cells/gram)
2 types of food poisoning or gastroenteritis:
It is associated with the ingestion of contaminated meat, poultry, and vegetables
Incubation period: 8 to 16 hours
Symptoms: Abdominal pain and watery diarrhea without fever
(+) Production of heat-labile enterotoxin
Diarrheal type
Emetic Type food poisoning is caused by?
Bacillus cereus Type 1
2 types of food poisoning or gastroenteritis:
It is associated with the ingestion of improperly stored cooked rice.
It is caused by B. cereus type 1
Incubation period: One to 6 hours
Symptoms: Abdominal cramps and profuse vomiting
(+) Production of heat-stable enterotoxin
Emetic type
It is the most commonly encountered laboratory contaminant
Bacillus subtilis ( Hay Bacllus)
It is a halophilic organism that can tolerate up to 7% NaCl
Bacillus subtilis ( Hay Bacllus)
It is the source of the bacitracin antibiotic
Bacillus subtilis ( Hay Bacllus)
It can cause an eye infection among prohibited drug users
Bacillus subtilis ( Hay Bacllus)
: BAP-colonies are larhe. Flat and dull with a “ground glass appearance”; may be Bhemolytic; and may exhibit pigment atoms
Bacillus subtilis ( Hay Bacllus)
Biochemical test: Ferments mannitol, xylose, and arabinose
Bacillus subtilis ( Hay Bacllus)
It is used as a biological indicator in sterilization methods
Bacillus pumilus
Culture; BAP-Colonies are large and moist; have a “blister-like appearance” and can be Beta
hemolytic
Bacillus pumilus
It is an insect pathogen
Bacillus thuringiensis
It produces parasporal crystals that can be utilized as a pesticide
Bacillus thuringiensis
