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Bacillus Clostridium Coreynebacterium Flashcards

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Biology 101 flashcards
1
Q

What are the members of bacillus species?

A

Pathogenic
Bacillus anthracis
Bacillus cereus

Non pathogenic
bacillus subtilis
Bacillus stearothermophillus

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2
Q

What is the first bacterium used for preparing attenuated vaccine?

A

Bacillus anthracis

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3
Q

What are the properties of bacillus anthracis?

A

Gram positive rods with square ends, frequently found on chains
Polypeptide capsule composed of D glutamate
Non motile
Spore forming
Aerobic
Grow on ordinary media

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4
Q

What are the lethal factors of anthrax bacilli?

A

Exo toxins, - anthrax toxin

  • protective antigen
  • edema factor
  • lethal factor

Polypeptide capsule
- anti phagocytic

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5
Q

What are the modes of transmission of bacillus anthracis?

A
  1. Cutaneous
  2. Inhalation
  3. Ingestion
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6
Q

How are humans most often infected with bacillus anthracis?

A

Mostly cutaneous. At the time of trauma to the skin, the spores on animal hides, wool, bristles etc can enter into the skin.

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7
Q

Is inhalation anthrax communicable?

A

No

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8
Q

What is the pathogenesis of Cutaneous Anthrax?

A
  1. Spore enters in to the skin through abraded skin, cuts or hair follicle
  2. Then it develops into a lesion 2-5 days after infection
  3. The lesion is surrounded by an area of edema and erytherma
  4. Lesion develops into a vesscile of 1-5 cm diameter after 2-3 days
  5. The lesion turns black due to hemorrhage.
  6. Lesion ulcerates and develops into a black buttoned Escher
  7. Ulcerative black lesion ultimately crusted over
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9
Q

what is pathogenesis of anthrax?

A

Spores of B. anthracis invade the human tissues.
They produce anthrax toxin.
Contains - Protective factor, edem factor and lethal factor,

  1. Edema factor is adenylate cyclase
  2. increase the intracellular concentration of cyclic AMP
  3. Outpouring of fluid from the cell into the extracellular space
  4. Edema
  5. Lethal factor is protease
  6. it cleaves the phosphokinase which activates the Mitogen activated protein kinase signal transduction pathway
  7. This pathway responsible for cell growth therefore inhibits cell growth.
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10
Q

What are the diseases caused by B. Anthracis and their clinical featuers?

A
  1. Cutaneous Anthracis
    - Painless ulcer with black eschar
    - Local oedemas
  2. Pulmonary Anthracis
    - Flu like symptoms, with dry cough and substernal pressure
    - Rapidly progresses to haemorrhagic mediastinitis, bloody pleural effusions, septic shock and death.
  3. Gastrointestinal Anthracis
    - vomiting abdominal pain with bloody diarrhoea
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11
Q

Why malignant pustule from Cutaneous Anthrax is called so?

What will happen if left untreated?

A

It called so because of it’s appearance, but it’s not malignant and not a pustule.

Occasionally multiple bullae develop with marked toxic effects. If it forms on the face or neck it becomes massively oedematous.

Usually cutaneous anthrax resolves on it’s own with eschar drying up and falling off minimal scarring without treatment in 1-2 weeks.

In one fifth of cases, if left untreated it may spread to blood, disseminate and then cause systemic infection.

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12
Q

What is the lab diagnosis for B anthacis?

A

Sample collection

  1. Pus in the case of malignant pustules
  2. Sputum in pulmonary anthrax
  3. Blood in septicaemia

Lab Diagnosis
A. Microscope,
Gram Positive rods with square ends, usually arranged in chains
B. Culture
37°C in blood agar media
Naked eye : non haemolytic large medusa head colonies
Microscope : Gram positive rods with square ends, usually arranged in chains
C. PCR
D. Serology : ELISA for antibodies

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13
Q

What does bacillus cereus cause?

A

Food poisoning

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14
Q

What is the pathogenesis of bacillus cereus?

A

Portal of entry : gastrointestinal tract

  1. Germinate when rice is kept warm for many hours
  2. Bacillus cereus produces 2 enterotoxins
  3. Enterotoxins are injested

a. One toxin causes ADP-ribosylation of G protein, which stimulates the adenyl cyclase and leads to concentration of cAMP within the enterocyte
b. Other enterotoxin is a super antigen

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15
Q

What are the clinical features of bacillus cereus poisoning?

A

2 syndromes

  1. One has shrit incubation period 4 hours. Consists primarily of nausea, vomiting similar to staphylococcus poisoning
  2. Other has long incubation period 18 hours. It features watery, non bloody diarrhea resembles clostridial gastroenteritis
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16
Q

Lab diagnosis and treatment of bacillus cereus?

A

No lab diagnosis

Disease is self limiting. Symptomatic treatment of ORS

17
Q

Treatment of bacillus anthracis?

A

Ciprafloxecin

There’s also vaccine over 18 month period. Annual boosters are given.

Incinerating animals that died of anthrax

18
Q

What are the characteristics of clostridium species?

A 
Gram positive
Spore forming
Motile
Anaerobic
Culture can be done on agar plate anaerobically or in anearobic media (cooked meat)
19
Q

Name a few clostridium species

A

Clostridium tetani - tetanus
Clostridium botulinum - botulism
Clostridium perfringes - gas gangrene and food poisoning
Clostridium defdicile - pseudomembranous colitis
Clostridium histolyticum, septicum, novyi - gas gangrene
Clostridium sordeli - gas gangrene

20
Q

What are the characteristics of clostridium tetani?

A 
Gram positive
Spore bearing
Spore is terminal give a drum sticks or tennis racket appearance
Anearobic
Motile
Produce powerful exo toxin tetanoplasmin
21
Q

What are the types of tetanus?

A 
Traumatic
Puerpal
Otogenic
Tetanus monotorum
Idiopathic
22
Q

What are the toxins produce by clostridium tetani?

A

Tetanolysin
Tetanoplasmin
Neurotoxin

23
Q

What is tetanoplasmin?

A

It’s an tetanus exo toxin. Polypeptide in nature and produce by vegetative cells at the wound site. Has one antigenic type

  1. It’s carried intra axon ally to the CNS
  2. Binds to ganglioside receptors
  3. Inhibit the release of mediators at the spinal synapses

Properties,

  1. Produced during the stationary phase of growth but released after the lysis of bacteria
  2. Protein in nature and synthesised as single polypeptide chain.
  3. Purified toxin is extremely potent, tetanus toxoid is produced from this toxin, antigenic but non toxic
  4. Binding of toxin in irreversible
24
Q

What is the pathogenesis of tetanus?

A

Mode of transmission- spores from soil
Route of transmission- from wounds, skin popping, umbilical stump
Incubation- 4-5 days

  1. Spore enters through wound
  2. Germinate under anaerobic condition
  3. Vegetative cells produce the exo toxin
  4. Carried axonally to the CNS
  5. Blind to glycoside receptors
  6. Blocks the release inhibitory mediators at spinal synapses
  7. Loss of inhibiton by upper motor neuron on lower motor neuron
  8. Exaggerated action of LMN on neuromuscular junction
  9. Spastic type of paralysis of muscle occurs
25
Q

Clinical features of tetanus

A
  1. Muscle spasms
  2. Lock jaw (trismus)
  3. Risus sardonicus
  4. Opisthotonos
  5. Respiratory failure
26
Q

How to prevent tetanus?

A 
Pre exposure prophylaxis
- immunisation with TT in childhood every 10 years thereafter
1 dose - 6 week of age
2 dose - 10 week of age
3 dose - 14 week of age

Post exposure prophylaxis

  1. Clean and debribe the wound
  2. Penicillin to prevent further infection
  3. If immunisation status know give tt booster
  4. If unknown Tetanus immune globulin as well as toxoid booster on different sites
27
Q

What are the characteristics of clostridium botulinum

A

Gram positive
Rod shaped
Spore is oval and terminal
Spores are widespread in soil and occasionally in stool
Motile
Anaerobic
Produce exotoxin which has 8 immunological types

28
Q

Use of botulinum toxin and mechanism of action of it

A
  1. Prepare Botox which remove wrinkles
  2. Minute of toxin is used to treat certain spasmodic muscle disorders like torticolis, writer’s cramp, blepharospasm

Mechanism of action
- neurotoxin, blocks the release of acetylcholine at the synapse
Produce flaccid paralysis

Made of 2 polypeptide subunits held together by disulphide bond
One binds to receptor on the neuron and other is a protease that degrade the proteins responsible for the release of acetylcholine

29
Q

Botulism

Agent, mode of transmission, route, source, types, diagnosis

A

Agent - exotoxin of clostridium botulinum
Cause - injection of pre formed toxin
Route - GIT

Source;

  1. Infected vacuum packed or canned food
  2. Alkaline vegetables like green beans, pepper, mushroom
  3. Smoked fish

Types

  1. Food borne
  2. Wound
  3. Infant botulism

Diagnosis

  1. Usually not culture
  2. Can can be seen in infected food. Injected to mice and it dies unless given anti toxin
30
Q

What is the treatment of botulism

A
  1. Trivalent antitoxin
  2. Respiratory support

Prophylaxis

  1. Proper sterilisation of all canned and vacuum packed food
  2. Food must be cooked enough to inactivate the toxin
  3. Swollen cans must be discarded
  4. Botulinum toxin is given to children in the epi schedule
31
Q

What is the pathogenesis of botulism?

A
  1. Clostridium botulism is widely spread in the soil
  2. Infect the food
  3. These food is canned and vacuum packed
  4. Spores survive and survive in anaerobic environment
  5. Toxin is produced in the anaerobic environment
  6. Ingestion of the pre formed toxin
  7. Absorbed from the gut
  8. Carries via blood to peripheral nervous system
  9. Blocks the release of acetylcholine
  10. Produces flaccid paralysis
32
Q

What is the clinical manifestations of botulism?

A
  1. Descending muscle paralysis
    - Diplopia
    - dysphagia
    - respiratory muscle failure
  2. No fever
33
Q

What are the features of clostridium perfringes

A 
Gram positive
Spore forming
Spores are oval and round shape
Non motile
Anaerobic 
Can ferment glucose and lactose with acid and gas

Microbiology (2 decks)

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