Making a microbiological diagnosis Flashcards
What is the Koch based diagnosis?
- presence of pathogen equals the diagnosis
- more than one pathogen responsible for disease
- little distinction between pathogen and commensal
What are lab results used for?
- our back up
- alert us to patients where infection is suspected but patient has not bothered to contact us
- help when antibiotics are unpredictable
- provide an intelligence system
Why are microbiology results not used?
the speed of progression of infection is much faster than the time taken to generate results
What is sensitivity?
the ability of a test to correctly identify those with the disease
What is specificity?
the ability of the test to correctly identify those without the disease
What are the normal flora?
bacteria which are found in our bodies on a semi-permanent basis without causing disease
What tests are used for specimens with a single pathogen?
throat swabs
infection control screening
MTB detection
What tests are used for specimens with a few organisms likely?
CSF
STI samples
What tests are used for specimens with multiple pathogens?
faeces
abscess puss
urine
What are the four methods for making a microbiological diagnosis?
- direct examination
- culture
- serology
- molecular
What is serological diagnosis able to do?
- detect high IgG/IgA/IgM concentration
- detect rising of falling titres
- detect antigens
What are examples of serological techniques?
precipitation
radioimmunoassay
immunofluroescence
What are the roles of a clinical microbiologist?
- provide high quality diagnostic tests
- provide clinical advice on the interpretation of diagnostic tests
- manage control of infection tissues within the hospital environment
