Introduction to Microbiology Flashcards
What are the possible infecting agents ?? (5)
- Bacteria
- Viruses
- Parasites
- Fungi
- Prions
What are the sterile sites in the body ?
Sterile sites should contain no micro-organisms, commensal or otherwise
- Blood
- CSF
- Lung
- Bladder
What are the non-sterile sites in the body ?
Non-sterile sites can contain commensal microbes that may not harm the body, but still show up in microscopy or cultures.
- Skin
- Nasopharynx
- Urethra
- Gut
What is the specimen collection for a urinary tract infection?
Mid stream urine
What is the specimen collection for a chest infection?
Sputum
What is the specimen collection for tonsillitis/pharyngitis
Throat swab
What is the specimen collection for the site of infection or a wound?
Swab or pus
What is the specimen collection for diarrhoea?
Faeces
What is the specimen collection for bacteraemia?
Blood culture
What is the specimen collection for meningitis?
CSF
What infecting agent is not visible in light microscope?
Viruses
Identify the advantages and disadvantages of Gram Stain and Microscopy
Advantage - Rapid
Disadvantage - Can’t usually identify particular species
Identify the advantages and disadvantages of Bacterial Culture
Advantage - Culture conditions are suitable for the expected species, and this method is able to identify particular species.
Disadvantage - Slow
How are species identified ?
First observable characters are used: - morphological - physiological - biochemical Then DNA based tests are done.
How are viruses diagnosed ?
- Viruses can only grow inside other cells, so a cell line must be inoculated.
- Light microscopy cannot detect viruses, so electron microscopy is used instead.
- Antigen detection and nucleic acid amplification is more widely used now as a method of diagnosis. - Serology is less common, but can still be used to determine immunity.
