Diagnosis of infectious disease Flashcards
Path for diagnosis of infectious disease? 8 steps
- Sick patient presents
- Likely cause?
- Can the likely bug grow on agar?
- Yes - culture and antimicrobial susceptibilities. No - immunoassay or molecule test (blood)
- Take the right specimen order the right test and store transport it correctly
- Results from lab
- Manage and treat patient
- Patient cured Yes, No - start again
How to take a blood culture?
Clean skin with iodine to prevent false results from skin flora.
Take 3x 10ml blood samples in 24 hr period
How to take throat swab?
Swab the back of the tonsils.
Most likely cause e.g. Streptococcus pyogenes
Nasopharyngeal swap how?
Up the nose. e.g. for whooping cough
What is sputum?
Mucous from the lungs.
How to take a sputum sample?
Patient rinses mouth and takes several deep breaths and then coughs into sterile container.
Most like cause of sputum sample?
e.g. S. pneumoniae
What is a stool culture?
Faeces
Most likely from urine sample?
E. Coli
How do we test for infectious disease? 3
Microbiology
Molecular testing
Immunology test
Example of a microbiology test?
Culture
Example of a Molecular test?
PCR
What is PCR?
photocopying little bits of genes. its an amplification machine, so we can see it.
Example of a immunology test?
looking at the antibodies and whether they identify certain organisms.
What is an anaerobic organism?
Any organism that does not require oxygen for growth. It may react negatively or die of oxygen if present.
