Chapter 5 - Infections Flashcards
Which antibiotics and/or classes of antibiotics work to inhibit:
A) cell wall synthesis
B) protein synthesis
C) nucleic acid synthesis
A) cell wall synthesis:
B-lactams = Penicillins, cephalosporins, monobactams, carbapenems
Glycopeptides = vancomycin, teicoplannin
B) protein synthesis: Aminoglycosides = gentamicin, amikacin Macrolides Tetracyclines Clindamycin Fusidic acid Linezolid
C) nucleic acid synthesis
Quinolones
Rifampicin
(Metronidazole, sulfonamides and trimethoprim work to inhibit folate synthesis)
What are your clinical signs and symptoms of an infection?
- Fever, aches and pain
- Presence of pus, swelling or redness in the potentially infected site
- new onset confusion (particularly in elderly)
- drowsiness, irritability and poor appetite in children
- changes in blood pressure, heart rate or respiratory rate
What are the biochemical results indicating an infection?
- Raised or depressed white cell count
- raised neutrophils
- raised C-reactive protein
- altered platelet levels
- raised erythrocyte sedimentation rate
- worsening renal function
Which antibiotics are the safest to use in pregnancy?
Penicillins and cephalosporins
What is another name for Benzylpenicillin?
Penicillin G
Are penicillins bacteriostatic or bactericidal?
Bactericidal
What is the mechanism of action of gentamicin?
Gentamicin = aminoglycoside antibiotic.
Disrupts bacterial protein synthesis by binding to the 30S ribosomal subunits and causing misinterpretation of mRNA.
What is the difference between time-dependent and concentration-dependent antibiotics?
Concentration dependent:
e.g gentamicin
Increasing baceriocidal activity with increasing concentration of drug, Continues to have bacteriocidal activity even after the concentration of antibotic has fallen below the MIC.
Time dependent:
e.g vancomycin
Increasing bacteriocidal activity does NOT occur with increasing amounts of antibiotics. Therapetutic effect only occurs within therapeutic range i.e 10-20mg/L for vancomycin. When antibiotic levels fall below MIC, therapeutic effect ceases, therefore next dose needs to be given ON TIME to maintain therapeutic levels.
What is used for the prophylaxis of rheumatic fever or group A streptococcal infection?
Rhemuatic fever = untreated throat infection as a result of group A streptococcus (Gram +ve)
Phenoxymethylpenicillin
Are aminoglycosides bactericidal or bateriostatic?
bactericidal
Aminoglycosides are active against gram positive or gram negative bacteria?
Mostly gram negative
Treatment with aminoglycosides should generally not exceed ………. days.
7
How is gentamicin usually dosed in adults with normal renal function?
5mg/kg - based on IBW
In adults with impaired renal function, how do we dose gentamicin?
3mg/kg - less than 20mL/min
What serious side effects may occur with gentamicin?
Nephrotoxicity and ototoxicity
Carbapenems are active againt what types of bacteria?
broad- spectrum: good cover against gram positive and gram negative
Carbapenems are not active against which superbug?
MRSA
Cephlasporins are active against what types of bacteria?
Broad spectrum: good cover against gram positive and gram negative
Which two cephlasporins are suitable for the treatment of CNS infections i.e meningitis?
Cefotaxime and ceftriaxone - all other cephlasporins penetrate cerebrospinal fluid poorly
What are the 1st generation cephlasporins?
Cefalexin
Cefradine
Cefadroxil
What are the 2nd generation cephlasporins?
Cefaclor
Cefuroxime
What are the 3rd generation cephlasporins?
Cefotaxime
Ceftazidime
Ceftriaxone
What is the cautionary and warning labels associated with oral cefuroxime?
Take with or after food - poorly absorbed, therefore given with food maximises absorption
Macrolides are active against what types of bacteria?
Broad spectrum: good cover against gram positive and gram negative
Also includes cover against atypicals - Chlamydia, Legionella and Mycoplasma
