Infection Flashcards
What are arthropods?
can cause disease directly by feeding on human blood/ tissue or indirectly via the transmission of pathogens to humans
What are some sterile sites that clinical samples can be collected from?
- bone marrow
- CSF (e.g for meningitis)
- tissue
- lower respiratory tract (should be sterile)
- bladder
What is sputum?
-contains secretions from the lung. mucus -> is expelled from the respiratory tract
-used to detect the presence of pathogens
- yellow/ green sputum= infection
-bloody sputum= TB/cancer
What is MSU?
midstream specimen of urine: used to detect urinary tract infections and to analyse the presence of bacteria/other pathogens
What are some non-sterile sites for sample collection?
- upper respiratory tract (streptococci, anaerobes, Candida albicans)
- skin (coagulase negative staphylococcus)
- GI tract
- vagine
- urethra
What things are important when collecting a sample?
1) collecting sample before antibiotics are given
2) avoided contamination
3) label specimens correctly
4) complete request form completely
5) transport sample to lab asap
What is the transport media for bacteria?
- Stuarts transport media: contains charcoal to inactivate toxic bacterial bi products
What is the transport media for viruses?
buffered salt solution containing serum (stabilises virus), contains antimicrobials to control overgrowth of contaminating bacteria and fungi
What is the job of the clinical microbiology reception?
- check specimen
- can accept or reject sample
What are the ACDP catgeory’s for biological agents?
1) category 1= unlikely to cause human disease
2) category 2= biological agent that can cause disease, hazardous to employees but unlikely to spread to community
3) category 3= can cause severe human disease, risk of spread in community, effective treatment
4) category 4= causes severe human disease, community spread, NO EFFECTIVE TREATMENT
What are some non culture techniques?
- direct microscopy
- antigen detection
- molecular microbiology: PCR etc
What are some culture techniques?
Solid agar
What is enriched agar used for?
1) horse blood agar: useful for demonstrating haemolytic of organisms
2) chocolate agar: blood is heated before aded to the agar - used for growing organisms such as N.gonorrhoeae
Why would you use selective agar for. C.Difficile sample?
1) to kill off any other organisms and keep the one we’re looking for
2) cycloserine and cefoxitin are both antimicrobials that are selective for c. difficile
What is differential media?
media where an indicator such as a dye has been added
