Introduction To Antibiotics And Antibiotic Resistance Flashcards
Types of antimicroials
Antibacterial, antifungals, antivirals and antiprotozoals
The 2 types of actions of antibiotics
Bacteriocidial - kill bacteria
Bacteriostatic- prevent multiplication of bacteria so they eventually die
How to chose an antibiotic
Is it active against the target organism?
Must reach site of infection (e.g cross blood brain barrier for meningitis)
Being the right formulation i.e must be oral if they will be at home
Making sure half life is appropriate for the amount it needs to be used.
Cant interact with other drugs they taking
Making sure its no toxic to the body
Remembering allergies
Checking whether it needs monitoring
How to measure antibiotic activity
Culture bacteria on agar plate with antibiotics and then measure the zone of clearance by measuring the diameter around the antibiotic
How to measure antibiotic activity using micro dilution *****
Uses broths with different concs of antibiotics. As the antibiotic concentration increases it becomes more cloudy. When b1st becomes cloudy shows the minimum inhibitory concentration that can be used
What is the E-test **
Measures resistance of an antibiotic on an exponential scale. Is a little swab piece of paper
Mechanisms of how antibiotics work
Cell wall synthesis disruption, cell membrane disruption, protein synthesis disruption, nuclei acid synthesis disruption
Name the 3 types of resistance
Intrinsic- no target for drug (permanent)
Acquired- new material passed over via horizontal transfer
Adaptive - organism response to stress
Mechanisms of resistance
Enzymes modify/ destroy the bacteria
Enzymes alter antibiotic targets
Mutations of target sites so antibiotics cant bind
Cellulitis case study - symptoms, causes and treatment
Infection of the deeper dermis and subcutaneous tissue = rubor, callor and tumour. It enters via inoculation through opening in skin.
Causes by staphylococcus or streptococcus (both gram pos)
The antibiotic used to treat is flucoxacilllin as as both strep and staph combated by this. It’s method d action is by disrupting the cell wall
If allergic to penicillin use clarithromyocin
UTI case study
Direct transfer of fecal matter into bladder. Treatment is trimethoprim which acts by inhibiting folic acid synthesis. This is needed for the synthesis of nucleic acids. The bacteria usually causing UTI is E.coli which is pink gram neg bacilli commonly found in the colon
Pneumonia (community acquired) case study
Infection of the lungs. Infected by droplet infection. Agar plate shows gram neg bascilli = haemohylisis bascillli. Treatment is amoxicillin (disrupts cell wal synthesis) or if allergic then use tetracycline (prevents protein synthesis)
What are beta lactams
Group of drugs containing beta lactam bring. Includes all penicillin derivatives
