Microbiology - Bottom Up Flashcards
Define a antimicrobial agent
Substance with inhibitory properties against microorganisms, with minimal effects of mammalian cells.
Define antibiotic
Substance that stops growth or kills bacteria.
Can be produced by other microorganisms or made synthetically
Define empirical therapy
A non selective antimicrobial therapy used when waiting for microbial identification would be inappropriate
Define Directed therapy
Therapy that targets a specific pathogen
Define resistance (in context of a microorganism)
Ability of microorganism to avoid the effects of an antimicrobial agent
Define susceptibility
Level of venerability of a microorganism to an antimicrobial
What are the main sites of action of antibiotics
Cell wall
Cell membrane
Protein synthesis
DNA synthesis
RNA synthesis
What class of antibiotics block cell wall synthesis
Beta-lactams
Glycopeptides
Name some beta-lactams
Penicillin
Cephalosporins
Monobactams
Carbapenems
Beta-Lactams mechanism of action
Inhibits transpeptidase enzymes
Weakens cell walls
Ruptures cells
Types of penicillins and examples of each
Narrow spectrum - benzylpenicillin or phenoxymethylpenicillin
Moderate spectrum - amoxicillin
Extended-spectrum - ticarcillin
What bacteria are benzylpenicillin and phenoxymethlypenicillin active against?
Streptococci
What is ticarcillin effective against
Streptococci and many coliforms E.g E. coli
What is piperscillin used to treat?
Pseudomonas aeruginosa
(Causes hospital acquired pneumonia)
Examples of Cephalosporins
Cefuroxime
Ceftazidime
Cefotexime
What are carbapenems used to treat?
Severe multi-bacterial antibiotic resistant infections
- Live sepsis
- peritonitis
Examples of carbapenems
Imipenem
Meropenem
Ertapenem
What are glycopeptides effective against
Gram positive bacteria