Antibiotics Flashcards
Why are antimicrobials so important?
Before anti-microbials, 90% of children with bacterial meningitis died. Strep throat was at times fatal, and ear infections sometimes spread to the brain. A third of patients with pneumonia died.
What is meant by selective toxicity?
Compounds harm pathogen not host.
What was the first effective antisyphilitic discovered in 1909?
“Salvarsan”
Arsenic containing
When was penicillin discovered and by who?
1928
Fleming
When was prontosil discovered?
1932
Domagk
Define antimicrobial.
Any substance active against microbes
Define antibiotic.
A naturally occurring product active against bacteria
Define broad spectrum.
Kills most germs Gram positive and Negative + or –
anaerobes
Define narrow spectrum.
Kills narrow range of microbes
Define bactericidal.
Actively kills bacteria
Define bacteriostatic.
Prevents bacteria multiplying
Bacteriostatic vs Bactericidal - depends on..? (2)
– Microorganism (bacterial inoculum)
– antibiotic concentration
When is bactericidal preferred? (2)
When inadequate penetration to infection site e.g. endocarditis, meningitis, osteomyelitis
If immune system is compromised e.g. neutropenia, renal failure, diabetes
Give examples of bacteriostatic antibiotics. (6)
Chloramphenicol Clindamycin Erythromycin Tetracyclines Trimethoprim Sulfonamides
Give examples of bacteriocidal antibiotics. (6)
Aminoglycosides Beta lactams Vancomycin Quinolones Rifampin Metronidazole
Describe a synergistic antimicrobial combination.
Give an example.
Their combined activity is greater than the sum of the individual activities – e.g B-lactam and aminoglycoside
Describe a antagonistic antimicrobial combination.
Give two examples.
The activity of one drug is compromised by the other – e.g Tetracycline or Chloramphenicol associated with B-lactam or aminoglycoside, or 2 B-lactams together
Describe the Therapeutic Index curve.
Antimicrobial conc over time - begins sub-therapeutic, then goes to therapeutic, and if rises too high = toxic. Then reduces back down into sub-therapeutic. The therapeutic range is between sub-therapeutic and toxic.
