Flashcards
8: Opportunistic pathogens
Cards in this deck (10)
- 1Koch's postulates- pathogen present in every case
- pathogen isolated and purely cultured
- infection re-infects healthy host
- the pathogen must be recoverable from the experimentally infected host - 2LIMITATIONS OF KOCH’S POSTULATESViruses
Polymicrobial infections
Infecting doses
Host effects - 3Fighting virulence factors - toxins e.g. - capsules e.g. - adhesins e.g.- diphtheria by toxoid immunisation
- S.pneumoniae by pneumococcul vaccination
- Uropathogenic E. coli by
Not yet - 4Evidence for a potential pathogen being clinical significant (particularly for bacteria) - isolated - evidence- in abundance, pure culture, >1, from deep tissues
- of local inflammation/immune response - 5changes to normal flora - with changes in hormonal physiology and development - when antibiotics select for a 'resistant flora’ - new organisms may be acquired- female genital tract and lactobacilli
- Clostridium difficile
- neonate from maternal genital tract during birth - 6Clostridium difficile (risk increases as age increases) - features - symptoms- Gram-positive, rod-shaped,
Spore forming, strictly anaerobic bacterium
- diarrhoea several times a day
fever, loss of appetite - 7C. difficile infection mechanism1. spores contaminate
2. disruption of the microbiota barrier effect
3. spore germination
4. gut colonisation
5. toxin production - 8Opportunistic infection - immunosuppression - breaching defences - foreign body - debility- cancer
- wound
- prosthesis
- ill health & old age - 9Latent pathogens - viral - bacterial - fungal - parasitic- Cytomegalovirus (CMV), Epstein-Barr (EBV), Herpes simplex
- Syphilis, Tuberculosis
- Cryptococcus neoformans
- Pneumocystis carinii - 10Post splenectomy sepsis - frequency - speed - severity - rapid intervention - prevention- 1/175 patients per yr
- hrs
- high sepsis & mortality
- informed patient & staff
- Antimicrobial prophylaxis
immunisation
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- Uni BIOL 243 - Medical microbiology Flashcards on 8: Opportunistic pathogens, created by Jumael Zafar on 07/02/2020.
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- Jumael Zafar
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