Gram-positive or Gram-variable bacilli
Sporulating
Aerobic or facultatively anaerobic
Catalase positive (most)
Capsulated
Motile by peritrichous flagella
Most bacilli are saprophytes
G+C content ranges from 32 to 69%.
Thermophilic (< 75°C) and psychrophilic (>5-8°C)
2. Scientific classification
Kingdom : Bacteria
Division : Firmicutes
Class : Bacilli
Order : Bacillales
Family : Bacillaceae
Genus : Bacillus
Cohn 1872
–
3. Species
– B. cereus
– B. subtilis
– B. polymyxa
– B. sphaericus
– B. anthracis
– B. coagulans
– B. circulans
– B. mycoides
– B. pumilus
– B. macerans
– B. licheniformis
– B. piliformis
4. General Characteristics of Bacillus
• Gram-positive or Gram-variable
bacilli
• Sporulating
• Aerobic or facultatively anaerobic
• Catalase positive (most)
• Capsulated
• Motile by peritrichous flagella
• Most bacilli are saprophytes
• G+C content ranges from 32 to
69%.
• Thermophilic (< 75°C) and
psychrophilic (>5-8°C)
9. General Characteristics
• G+ rods with square cut ends
• Facultative anaerobe
• Thiamin growth requirement
• Glutamyl-polypeptide capsule
• Nonmotile
• Forms oval, centrally located endospores
10. Cultural characteristics
• Can not grow on MCA.
• Mucoid colony on bicarbonate agar incubated
overnight under CO₂.
• Inverted fur appearance on gelatin agar.
• White colony on PLET agar
• Lysis by gamma phage.
13. Culture
• Other non-selective
media
• Nutrient agar – colonies
– medusa head
appearance on low
power microscopy
• Blood agar – usually
non-haemolytic
15. History of Anthrax (Early history)
• Although anthrax dates back more than 3,000 years, it
was not recognized as a disease until the 18th century.
• 1500 B.C - A “plague of boils” in Egypt affected the
Pharaoh’s cattle. ‘Boils’ are symptomatic of anthrax.
• 1600s - The “Black Bane” thought to be anthrax, in
Europe kills over 60,000 cattle.
19. Anthrax
• From the Greek word anthrakos for coal
• Caused by spores
• Primarily a disease of domesticated & wild animals
– Herbivores such as sheep, cows, horses, goats
• Natural reservoir is soil
– Does not depend on an animal reservoir making it hard to eradicate
– Cannot be regularly cultivated from soils where there is an absence of
endemic anthrax
– Occurs sporadically throughout US
• Anthrax zones
– Soil rich in organic matter (pH < 6.0)
– Dramatic changes in climate
20. SUSCEPTIBILITY
• All mammals apear to be susceptible to
anthrax,ruminants such as cattle ,sheep and
goat are most susceptible,followed by horse
and swine.
21. Ant hrax Inf ecti on &Sp read
• May be spread by streams, insects, wild
animals, birds, contaminated wastes
• Animals infected by soilborne spores in food
& water or bites from certain insects
• Humans can be infected when in contact
with flesh, bones, hides, hair, & excrement
– nonindustrial or industrial
– cutaneous & inhalational most common
22.
23. Clinical Signs
• Many species affected
– Ruminants at greatest risk
• Three forms
– Peracute
– Ruminants (cattle, sheep, goats, antelope)
– Acute
– Ruminants and equine
– Subacute-chronic
– Swine, dogs, cats
24. SYMPTOMS IN ANIMALS
• Sings are fever upto 107 F,muscle tremors,
respiratory distress and convulsion.Death
occurs quickly and often before symptoms are
observed.
• Animals that die of anthrax bloat
quickly.Blood may come from the nose and
other body openings.
25. Three forms of Anthrax in humans
• Cutaneous anthrax
– Skin
– Most common
– Spores enter to skin through small lesions
• Inhalation anthrax
– Spores are inhaled
• Gastrointestinal (GI) anthrax
– Spores are ingested
– Oral-pharyngeal and abdominal
26.
27. Pathogenesis
• The infectious dose of B.
anthracis in humans by any
route is not precisely known.
– Rely on primate data
– Minimum infection dose of ~
1,000-8,000 spores
– LD50 of 8,000-10,000 spores
for inhalation
• Virulence depends on 2 factors
– Capsule
– 3 toxins http://www.kvarkadabra.net/index.html?/biologija/teksti/biolosko_orozje.htm
28. Capsule
• Glycocalyx
– Sticky, gelatinous polymer external
to cell wall
• pX02 plasmid
• Made up of D-glutamic acid
• Non-toxic on its own
• Only encapsulated B. anthracis virulent
• Most important role during
establishment of disease
– Protects against phagocytosis &
lysis during vegetative state
http://textbookofbacteriology.net/BSRP.html
29. Toxins
• pX01 plasmid
• AB model
– Binding
– Activating
• Protective antigen (PA), edema
factor (EF) & lethal factor (LF)
– Make up 50% of proteins in
the organism
• Individually non-toxic
– PA+LF lethal activity
– EF+PA edema
– EF+LF inactive
– PA+LF+EF edema &
necrosis; lethal
http://www.rcsb.org/pdb/molecules/pdb28
_1.html
31. Genetics
• 1 chromosome
– 5.2 million bp
– Ames strain sequenced
• 2 plasmids
– px01
– 184 kbp
– Pathogenicity island
– pX02
– 95.3 kbp
– Capsule
• Anthrax receptor
– Occurs > than ten thousendfold on
macrophage cell
– ATR/TEM8 gene
– Chromosome 4 gib.genes.nig.ac.jp/single/ main.php?spid=Ban
32. Diagnosis
• Gram stain
• Culture of B. anthracis from the blood, skin lesions, vesicular fluid, or respiratory
secretions
• X-ray and Computed Tomography (CT) scan
• Rapid detection methods
- PCR for detection of nucleic acid
- ELISA assay for antigen detection
- Other immunohistochemical and immunoflourescence
examinations
- These are available only at certain labs
37. Vaccination
• Livestock in endemic areas
• Sterne strain
– Live encapsulated spore vaccine
• No U.S. vaccine for pets
– Used in other countries
– Adjuvant may cause reactions
• Working dogs may be at risk
38. TREATMENT
Many antibiotics are effective against
anthrax in humans, but treatment
must be started early.
Ciprofloxacin is recommended for
treatment; penicillin G, along with
gentamicin or streptomycin, has
previously been used to treat anthrax.
39. Recent research
• The Ames ancestor chromosome was sequenced in
2003 and contributes to the identification of genes involved
in the virulence of B. anthracis
• . Recently, B. anthracis isolate H9401 was isolated from a
Korean patient suffering from gastrointestinal anthrax. The
goal of the Republic of Korea is to use this strain as a
challenge strain to develop a recombinant vaccine against
anthrax.
Chun, J.-H.; Hong, K.-J.; Cha, S. H.; Cho, M.-H.; Lee, K. J.; Jeong, D. H.; Yoo, C.-K.; Rhie, G.-e. (18
July 2012).
"Complete Genome Sequence of Bacillus anthracis H9401, an Isolate from a Korean Patient with A
. Journal of Bacteriology.
40.
41.
42. Bacillus cerus
• The word Bacillus means ‘Small rod’ and
cereus means ‘Wax- like’.
• It is derived from Latin language.
• The name itself reflects the morphology of
B.cereus
43.
44.
45. TOXINS
• B.cereus produces one type of emetic toxin and three types of
enterotoxin.
• Three pore forming enterotoxin responsible for diarrhoeal
syndrome are 1. Hemolysin bl (Hbl)
• 2. Non – Hemolytic enterotoxin (Nhe)
• 3. Cytotoxin K (cyt K)
• Hbl consists three different protein components L1, L2, B.
46. SYNDROME
• B.cereus is an opportunistic pathogen cause
infections like
• 1. Diarrhoeal syndrome
• 2. Emetic syndrome
• Transmission is predominantly foodborne for
both.
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Large (0.5 x 1.2 to 2.5 x 10 um)
Most are saprophytic contaminants or normal flora
Bacillus anthracis is most important memberRapidly differentiates from Clostridium
Bacillus spp. are ubiquitous
Soil, water, and airborne dust
Thermophilic (&lt; 75°C) and psychrophilic (&gt;5-8°C)
Can flourish at extremes of acidity & alkalinity (pH 2 to 10)
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B. cereus family???
The capsule is not found in cultured bacteria unless the bacteria are grown on bicarbonate containing media and in the presence of increased CO² concentrations.
This culture was probably incubated at an increased CO2 tension (5% CO2) which greatly enhances production of the poly-D-glutamyl capsule and accounts for the mucoid colony type.
&lt;number&gt;
&lt;number&gt;
&lt;number&gt;
Virtually all mammals and some birds can contract anthrax. Clinical signs in animals differ by the species, with ruminants being the most at risk. The peracute form most often affects ruminants, including cattle, sheep, and goats. The acute form will affect ruminants, as well as horses. The subacute or chronic form most often affects swine, dogs, and cats. The incubation period varies from 1-20 days. In herbivores, infections become apparent after 3-7 days, while in pigs it usually takes 1-2 weeks.
[This antelope is hemorrhaging from the nose. Source: World Health Organization]
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Annual vaccination of livestock in endemic areas is recommended. The most widely used vaccine is the Sterne-strain vaccine. It is a non-encapsulated, live variant strain of B. anthracis developed in 1937. Immunity develops 7 to 10 days after vaccination. The vaccine produced in the U.S. is licensed for use in livestock only (cattle, sheep, horses, goats, and swine). No U.S. anthrax vaccine is licensed for use in pets. In other countries, live spore vaccines produced from the Sterne strain have been used to vaccinate pets and exotic species. The vaccine contains saponin as an adjuvant and its use in cats and dogs may produce injection site reactions. Cases in domestic cats are very rare. Working dogs might put themselves at risk by exposure to dead carcasses.
