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24 Cards in this Set
- Front
- Back
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What is Diphtheria? |
An aerobic, gram-positive, non-endospore forming, pleomorphic, often club shaped bacillus (rod) bacteria. |
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what infection is diphtheria classified as? |
Classed as an upper respiratory infection or cutaneous infection |
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How can you contract diphtheria? |
through wounds. In the past, it was transferred by droplets. |
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How does diphtheria infect people? |
It adheres to the mucosal epithelial cells where an exotoxin is released from an endosome which induces an inflammatory response, leading to tissue necrosis. If lysogenised by a phage, the toxin interferes with protein synthesis. A tough, greyish membrane is formed that can obstruct the airway. |
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what can be used to treat diphtheria? |
Antibiotics can't work on its own. Must be used with antitoxins. |
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Can you prevent diphtheria? |
yes, the DTap vaccine (a combination vaccine of pertussis, diphtheria and tetanus). Since the introduction of the vaccine, incidence has dropped dramatically in the UK. |
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Are there problems of diagnosis with diphtheria? |
Yes, lab diagnosis is difficult. |
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What is pertussis? |
Pertussis (whooping cough), is an aerobic gram-negative coccobacillus. |
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How does pertussis infect an individual? |
Bacterial attach to cilia cells in the trachea, impeding their muchciliary action and eventually destroy them. the tracheal cytotoxin damages filial cells and move into the bloodstream. |
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Name a virulence factor of pertussis |
adenylate cyclase toxin a invades eukaryotic cells by a calcium dependent mechanism in which the cya A catalytic domain is moved across the target cell membrane. - causes whooping cough that is severe, 1-6 times a day, can cause broken ribs. |
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what are the 2 stages of pertussis? |
1: common cold symptoms 2. whooping cough |
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Vaccine for pertussis? |
Yes, DTap used for protection. Declines after a few years however. |
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How do you diagnose pertussis? |
PCR |
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Treatment for pertussis? |
erythromycin and other macrolides. However, not effective after the paroxysmal coughing stage. |
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What is tetanus? |
an obligately, anaerobic, endospore forming, gram positive rod |
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what is the causative bacteria of tetanus? |
clostridium tetani |
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entry of tetanus to person? |
abundant in soil and faeces can enter from wounds. if conditions allow, tetanopasmin is produced and is carried to the CNS where is binds neurons. It blocks the release of inhibitory mediators in spinal synapses causing overactivity of motor neurones. |
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symptoms of tetanus? |
Contracting muscles and spasms. eventual death from spasming of respiratory organs. |
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treatment of tetanus? |
Human Angti- tetanus immunoglobulin should be give as soon as tetanus is suspected. Antibiotics are useless once the bacteria reaches the CNS. |
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Can tetanus be prevented? |
DTaP vaccine. Discussed perviously. |
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Causative agent of cholera:
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Vibrio cholerae: a gram-negative, curved rod with single polar flagellum |
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what type of pathogen is cholera? |
a waterborne pathogen |
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what is the mechanism that causes symptoms? |
acts locally and does not invade the intestinal wall. the cholera toxin is released in the small intestine causing the host cells to secrete water and electrolytes activating CFTR efflux of Cl- |
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how much water is lost a day to cholera |
12-20 litres |
