11.1 antibiotics Flashcards
give an example of some folic acid antagonists
trimethoprim and sulphonamines
are combined for treatment
inhibit folic acid synthesis so inhibit nucleic acid synthesis
what antibiotic classes target protein synthesis
aminoglycosides
macrolides
tetracyclines
what antibiotic classes target cell wall synthesis
beta lactams
glycopeptides
what groups of people are at risk of infection?
- peri operative (prevention of surgical site infections
- short term (meningitis contacts)
- long term (asplenia, immunodeficiency)
what questions could you use to identify the likely cause of infection?
- anatomical site
- duration of illness
- age
- time of year
- past medical history
- occupational history
how can you measure antibiotic activity?
disc testing
antibacterial disc on agar plate seeded with bacterium
wider zone of inhibition of bacterial growth around antibacterial disk = higher activity
what is the minimum inhibitory concentration?
the minimum concentration of antibiotic required to prevent bacterial growt in vitro h
what is time dependant killing of bacteria with antibiotics?
successful treatment requires prolonged antibiotic presence at site of infection
but not high concentration
what is concentration dependant killing of bacteria with antibiotics?
successful treatment requires high antibiotic concentration at site of infection
but not for long
how do bacteria become resistant to antibiotics?
- mutation of bacterial DNA in chromosome or plasmid
- acquisition of pre formed resistance genes between bacteria on plasmids
what evidence is there than antibacterials cause resistance?
- lab evidence
- ecological studies
- individual level date
what are the consequences of resistance?
- transferable resistance between bacteria (horizontal gene transfer)
- transfer resistance between people (whole organism transfer)
what are some adverse events of antibiotics?
- organ toxicity e.g nephrotoxicity and hepatotoxicity
- allergic reactions
what is the genetic basis of antibiotic resistance?
chromosomal gene mutation and horizontal gene transfer
how can the spread of antibiotic resistance be controlled?
- hand hygiene
- decolonisation of patients
- isolation or cohorting
- minimise infection risk
- monitor and control antibiotic prescribing
