Antimicrobial therapy 1 and 2 AND Antimicrobial therapy reading Flashcards
(159 cards)
When are ABs most effective?
When they supplement the body’s natural defences rather than being used alone
What is the most important resistance code?
R plasmids (may involve genes that impart resistance to unrelated ABs)
What may impair the effectiveness of antimicrobial therapy? 3
urinary calculi, FB or need for surgical drainage
How would the mechanism of bacterial killing affect the type of drug?
Concentration versus time-dependent actions
Why are more selective drugs preferred?
less likely to disrupt the normal flora
What should be considered when choosing whether to use a bacteriostatic or bacteriocidal drug?
Bactericidal drugs are often favoured because they may be more effective when host defences are impaired. However, there may be little difference in efficacy between bactericidal and bacteriostatic drugs when treating non‐critical infections in otherwise healthy patients.
To which organ is gentamicin toxic?
nephrotoxicity
Which breed of dog can’t be given sulphonamides?
Dobermans
What organ system is affected by erythromycin?
GIT
Name 5 bacteriostatic drugs
tetracyclines, chloramphenicol, non‐potentiated sulphonamides, macrolides and lincosamides
How and when do bacteriostatic drugs work?
temporarily inhibit the growth of an organism but the effect is reversible once the drug is removed. For these drugs to be clinically effective the drug concentration at the site of the infection should be maintained above the MIC throughout the dosing interval. As a result, adherence to correct dose timing is important and clients should be instructed to administer drugs every 24, 12 or 8 hours rather than once, twice or three times daily.
List 6 bacteriocidal drugs
aminoglycosides, cephalosporins, fluoroquinolones, metronidazole, penicillins, potentiated sulphonamides
When to use bacteriocidal drugs
- depends on nature or site of infection
- reduced immunocompetence of host
How are bacteriocidal drugs further classified?
time or concentration dependent
List time-dependent bacteriocidal drugs 3
penicillins, cephalosporins, TMPS
Why shouldn’t time dependent bacteriocidal drugs be given with bacteriostatic drugs?
bacteria need to be multiplying for bacteriocidal drugs to be effective
How high a dose of bacteriocidal drugs should be given?
above MIC for 80% of 24 hours to reduce risk of resistance emerging
Is there any benefit achieivng a Cmax 2-4 times the MIC for bactericidal drugs?
no
List 3 concentration dependent bacteriocides
aminoglycosides
fluorquinolones
metronidazole
What determines antibacterial success with concentration dependent bactericides (aminoglycosides, fluoroquinolones and metronidazole)
all 3 - peak concentration
fluoroquinolones - area under the plasma concentration/time curve
Common bacterial cause of UTIs
E.coli
Common cause of skin infectins
Staphylococcus spp
Which group of bacteria are you likely to find in pyothorax and abscesses?
obligate and facultative anaerobes
Where might bacteria come from in supparative cholangiohepatitis?
GIT contents - gram negative plus anaerobes