Antimicrobial Flashcards
maintains activity against most macrolide- resistant gram-positive organisms and does not induce a common macrolide resistance mechanism
Ketolides (Telithromycin)
inhibits the addition of amino acids to the growing peptide chain by reversibly binding to the 50S ribosomal subunit, inhibiting transpeptidation
Chloramphenicol
Lipopeptide agent for gram negative bacteria that could also be toxic to humans
Polymyxins
Example for this resistance mechanism is:
Staphylococcal resistance to
penicillin; resistance of
Enterobacteriaceae and
Pseudomonas aeruginosa
to several penicillins, cephalosporins, and aztreonam
Enzymatic destruction
broad spectrum of activity but is bacteriostatic
Tetracyclines
penicillin-resistant Neisseria gonorrhoeae)
Spread of “old” genes to new hosts
Examples of β-Lactam antibiotics
penicillins, cephalosporins
Example for this resistance mechanism is: Enterococcal and Staphylococcus aureus resistance to vancomycin
Altered target
Inhibit protein synthesis-interfere with the binding of the tRNA-amino acid complexes to the ribosome
Tetracyclines
Example for this resistance mechanism is: Enterococcal resistance to streptomycin (may also be mediated
by enzymatic modifications)
Altered target
Lipopeptide agent for gram positive
Daptomycin
this enzyme is capable of opening the beta-lactam ring
once it opens the beta-lactam ring it will alter its structure
and would prevent its subsequent binding to your penicillin binding proteins.
beta lactamase
Inhibit protein synthesis-by blocking the initiation step and translocation of peptidyl- tRNA from the A site to the P site
Oxazolidinones
Effective on most Aerobic Gram negative and certain gram positive bacteria (S.aureus)
Aminoglycosides
Resistance resulting from altered cellular physiology and structure caused by changes in a microorganism’s genetic makeup
Acquired resistance
Protein synthesis is inhibited by drug binding to the 23S ribosomal RNA (rRNA) on the bacterial 50S ribosomal subunit and subsequent disruption of
the growing peptide chain by blocking of translocation.
Macrolide-Lincosamide-Streptogramin group
methicillin-resistant
staphylococci, vancomycin-resistant enterococci)
Emergence of “new” genes
Inhibit protein synthesis-binding to protein receptors on the organism’s 30S ribosomal subunit
Aminoglycosides
Antimicrobial agent good for Gram-positive and gram negative (except P. aeruginosa)
Sulfamethoxazole
Act by binding PBPs (penicillin-binding proteins)
β-Lactam antibiotics
β-lactamase–mediated resistance to advanced cephalosporins in Escherichia coli and Klebsiella spp.
Mutations of “old” genes resulting in more potent
resistance
most common Quinolones
Ciprofloxacin
Effective for Gram positive bacteria, mycoplasmas, treponemes, and rickettsiae
Macrolides
effective for Anaerobic gram-positive bacteria
Lincosamides
Chemical derivatives of erythromycin A and other macrolides (); Inhibit protein synthesis-bind to the 50S subunit of the bacterial ribosome
Ketolides (Telithromycin)
Example for this resistance mechanism is: Gram-positive and gram-negative resistance to aminoglycosides
Enzymatic
modification
Disrupt the folic acid pathway
Sulfonamides
Example for this resistance mechanism is: Aminoglycoside resistance in a variety of gram-negative bacteria
Decreased uptake
because of the large size of these compounds they cannot penetrate to the outer membrane of most of your gram negatives
Glycopeptides (Vancomycin)
part of the molecule was
produced by the fermentation process using the
appropriate microorganisms and the product is
then further modified by a chemical process
Semi-synthetic
Example for this resistance mechanism is: P. aeruginosa resistance to imipenem
Decreased uptake
Binds to and disrupts the cell membrane and inserts its hydrophobic tail into the membrane, disrupting the cell membrane and increasing
its permeability, which results in cell death
Lipopeptide
Resistance resulting from the normal genetic,structural, or physiologic state of microorganisms
Intrinsic resistance
Potent bactericidal agents and have a broad spectrum of activity
Quinolones
Binds to the end of peptidoglycan
Glycopeptides
Example for this resistance mechanism is: Staphylococcal resistance to methicillin and other available beta-lactams
Altered target
Inhibit bacterial growth but generally do not kill
the organism
Bacteriostatic Agents
semisynthetic antibiotics that bind to the enzyme DNA-dependent RNA polymerase and inhibit synthesis of RNA
Rifampin
Identify Antimicrobial agent classification: penicillins, cephalosporins
β-Lactam antibiotics
Identify Antimicrobial agent classification: Vancomycin
Glycopeptides
Identify Antimicrobial agent classification: daptomycin)
Lipopeptides
Identify Antimicrobial agent classification: Sulfamethoxazole
Sulfonamides
ciprofloxacin, levofloxacin, norfloxacin, ofloxacin, pefloxacin)
Fluoroquinolones
telithromycin
Ketolides
erythromycin, azithromycin, clarithromycin
Macrolides
Doxycycline or minocycline
Tetracyclines
linezolid and tedizolid
Oxazolidinones
Quinupristin-dalfopristin
Streptogramins
