Flashcards in Antimicrobial agents Deck (114)
What is the difference between bactericidal and bacteriostatic?
- Bactericidal actively kills bacteria whereas bacteriostatic prevents bacteria multiplying
What is the difference between an antimicrobial and an antibiotic?
An antimicrobial is any substance that is active against microbes whereas an antibiotic is a naturally occuring product active against bacteria
What do broad-spectrum bacteria kill?
Gram positives, negatives and/or negative anaerobes
What do bacteriostatic antibiotics require in order to be effective?
A functioning host immune system
What antibiotics effect the folic acid metabolism of bacteria?
What antibiotics effect the cell wall synthesis of bacteria?
- Beta lactams
What do Quinolones inhibit?
What does Metronidazole inhibit?
What does rifampicin inhibit?
DNA-directed RNA polymerase
What antibiotics inhibit protein synthesis?
- Which ones inhibit 50S and which ones inhibit 30S
What do polymyxins inhibit?
Cytoplasmic membrane structure (gram negatives)
Name some mostly anti-gram-positive antimicrobials?
- Fusidic acid
Name some mostly anti-gram-negative antimicrobials?
- Monobactams (Aztreonam)
Name types of broad spectrum antimicrobials?
- Beta lactams (e.g carbapenems, amoxicillin/clavulanate, piperacillin/tazobactam, cephalosporins)
- Chloramphenicol (gram positives, negatives, atypicals, anaerobes)
- Tetracycline (gram positives, negatives, atypicals and anearobes, spirochetes)
Describe the concept of the magic bullet?
A compound which would harm only the pathogen and not the host - refers to selective toxicity
What infections are difficult to treat due to inadequete penetration of antimicrobials into the target site?
Give an example of synergistic antimicrobials?
Beta-lactams with aminoglycosides (often used to treat endocarditis)
Give examples of antagonistic antimicrobials?
- Tetracycline or chloramphenicol with Beta lactams (or 2 beta lactams together, like flucloxacillin with amoxicillin)
Give an example of drugs with high therapeutic indexes?
Give an example of drugs with low/narrow therapeutic indexes?
What type of gram negative antimicrobials are intrinsically resistant to polymyxin (colistin)?
What can chloramphenicol be toxic to?
Bone marrow (can cause aplastic anaemia)
What is chloramphenicol mainly used for
- Eye drops
- Meningitis in those with penicillin allergy
Describe the difference between eukaryote and prokaryote ribosomes?
- Prokaryotes contain a 70S ribosome with a 50S and 30S subunit
- Eukaryotes contain an 80S ribsome with a 60S and 40S subunit
Name 2 Beta-lactamase susceptible narrow spectrum penicillins?
- Penicillin V and G
Name 2 Beta-lactamase resistant penicillins?
(Also Methicillin and Oxacillin, but these are not used clinically)
Name 2 Beta-lactamase susceptible broad spectrum penicillins?
- Ampicillin and Amoxicillin
Name penicillins with Beta-lactamase inhibitors?
- Amoxicillin and clavulanic acid
- Piperacillin and tazobactam (anti-pseudomonal), this is even broader spectrum
What are examples of carbapenems? (type of Beta lactams that are active against gram negatives)
- Meropenem and imipenem
- Etapenam (not anti-pseudonomal)