Bacillus Clostridium Coreynebacterium Flashcards
What are the members of bacillus species?
Pathogenic
Bacillus anthracis
Bacillus cereus
Non pathogenic
bacillus subtilis
Bacillus stearothermophillus
What is the first bacterium used for preparing attenuated vaccine?
Bacillus anthracis
What are the properties of bacillus anthracis?
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
What are the lethal factors of anthrax bacilli?
Exo toxins, - anthrax toxin
- protective antigen
- edema factor
- lethal factor
Polypeptide capsule
- anti phagocytic
What are the modes of transmission of bacillus anthracis?
- Cutaneous
- Inhalation
- Ingestion
How are humans most often infected with bacillus anthracis?
Mostly cutaneous. At the time of trauma to the skin, the spores on animal hides, wool, bristles etc can enter into the skin.
Is inhalation anthrax communicable?
No
What is the pathogenesis of Cutaneous Anthrax?
- Spore enters in to the skin through abraded skin, cuts or hair follicle
- Then it develops into a lesion 2-5 days after infection
- The lesion is surrounded by an area of edema and erytherma
- Lesion develops into a vesscile of 1-5 cm diameter after 2-3 days
- The lesion turns black due to hemorrhage.
- Lesion ulcerates and develops into a black buttoned Escher
- Ulcerative black lesion ultimately crusted over
what is pathogenesis of anthrax?
Spores of B. anthracis invade the human tissues.
They produce anthrax toxin.
Contains - Protective factor, edem factor and lethal factor,
- Edema factor is adenylate cyclase
- increase the intracellular concentration of cyclic AMP
- Outpouring of fluid from the cell into the extracellular space
- Edema
- Lethal factor is protease
- it cleaves the phosphokinase which activates the Mitogen activated protein kinase signal transduction pathway
- This pathway responsible for cell growth therefore inhibits cell growth.
What are the diseases caused by B. Anthracis and their clinical featuers?
- Cutaneous Anthracis
- Painless ulcer with black eschar
- Local oedemas - Pulmonary Anthracis
- Flu like symptoms, with dry cough and substernal pressure
- Rapidly progresses to haemorrhagic mediastinitis, bloody pleural effusions, septic shock and death. - Gastrointestinal Anthracis
- vomiting abdominal pain with bloody diarrhoea
Why malignant pustule from Cutaneous Anthrax is called so?
What will happen if left untreated?
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.
What is the lab diagnosis for B anthacis?
Sample collection
- Pus in the case of malignant pustules
- Sputum in pulmonary anthrax
- 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
What does bacillus cereus cause?
Food poisoning
What is the pathogenesis of bacillus cereus?
Portal of entry : gastrointestinal tract
- Germinate when rice is kept warm for many hours
- Bacillus cereus produces 2 enterotoxins
- 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
What are the clinical features of bacillus cereus poisoning?
2 syndromes
- One has shrit incubation period 4 hours. Consists primarily of nausea, vomiting similar to staphylococcus poisoning
- Other has long incubation period 18 hours. It features watery, non bloody diarrhea resembles clostridial gastroenteritis
Lab diagnosis and treatment of bacillus cereus?
No lab diagnosis
Disease is self limiting. Symptomatic treatment of ORS
Treatment of bacillus anthracis?
Ciprafloxecin
There’s also vaccine over 18 month period. Annual boosters are given.
Incinerating animals that died of anthrax
What are the characteristics of clostridium species?
Gram positive Spore forming Motile Anaerobic Culture can be done on agar plate anaerobically or in anearobic media (cooked meat)
Name a few clostridium species
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
What are the characteristics of clostridium tetani?
Gram positive Spore bearing Spore is terminal give a drum sticks or tennis racket appearance Anearobic Motile Produce powerful exo toxin tetanoplasmin
What are the types of tetanus?
Traumatic Puerpal Otogenic Tetanus monotorum Idiopathic
What are the toxins produce by clostridium tetani?
Tetanolysin
Tetanoplasmin
Neurotoxin
What is tetanoplasmin?
It’s an tetanus exo toxin. Polypeptide in nature and produce by vegetative cells at the wound site. Has one antigenic type
- It’s carried intra axon ally to the CNS
- Binds to ganglioside receptors
- Inhibit the release of mediators at the spinal synapses
Properties,
- Produced during the stationary phase of growth but released after the lysis of bacteria
- Protein in nature and synthesised as single polypeptide chain.
- Purified toxin is extremely potent, tetanus toxoid is produced from this toxin, antigenic but non toxic
- Binding of toxin in irreversible
What is the pathogenesis of tetanus?
Mode of transmission- spores from soil
Route of transmission- from wounds, skin popping, umbilical stump
Incubation- 4-5 days
- Spore enters through wound
- Germinate under anaerobic condition
- Vegetative cells produce the exo toxin
- Carried axonally to the CNS
- Blind to glycoside receptors
- Blocks the release inhibitory mediators at spinal synapses
- Loss of inhibiton by upper motor neuron on lower motor neuron
- Exaggerated action of LMN on neuromuscular junction
- Spastic type of paralysis of muscle occurs
