Antimicrobials Flashcards
What class is Erythromycin?
Macrolides
What class is Gentamicin?
Aminoglycosides
What class is Doxycycline?
Tetracycline
What class is Trimethoprim-Sulfamethoxazole?
Antimetabolites
What class is Ciprofloxacin?
Fluoroquionolones
What class is Levofloxacin?
Fluroquinolones
What class is Penicillin?
Penicillins
What class is Imipenem?
Carbapenems
What class is Cefazolin?
Cephalosporins
What class is Vancomycin?
Carbapenems
What class is Cefuroxime?
Cephalosporins
What class is tetracycline?
Tetracycline
What class is Clindamycin?
Clindamycin
What class is Tobramycin
Aminoglycosides
What class is meropenem
Carbapenems
What class is Piperacillin?
Penicillins
What class is Doripenem?
Carbapenems
What class is Oxacillin?
Penicillins
What class is Ceftazidime?
Cephalosporin
What class is amikacin?
Aminoglycosides
What class is Cefepime
Cephalosporins
How many interactions occur between a patient, organism and antimicrobial agent?
6
What group do penicillins work with?
Both GP and GN
What group do Cephalosporins work with?
Was GPC NOW it is GNR
What group do Glycopeptides work with?
GP (ans non-fermentive GNR)
What group do Clindamycins work with?
GP and anaerobes
What is the mechanism of Penicillins?
Bactericidal, stops cross linking of cell wall
What is the mechanism of Cephalosporins?
Bactericidal, stops cross linking of cell wall
What is the mechanism of Glycopeptides?
Bactericidal, inhibits cell wall synthesis LARGE
What is the mechanism of Fluroquinodines?
Stops topoisomerase and thus DNA synthesis
What is the mechanism of Aminoglycosides?
Bactericidal, inhibits 30s protein synthesis
What is the mechanism of Tetracyclines?
Bacteriostatic, inhibits 30s Protein synthesis
What is the mechanism of Chloramphenicol?
Bacteriostatic, inhibits protein synthesis
What is the mechanism of macolides?
Bacteriostatic, inhibits 50s protein synthesis
What is the mechanism of clindamycin?
Bacteriostatic AND Bactericidal, inhibits 50s portion synthesis
What is the mechanism of Antimetabolites?
Bacteriostatic, Folic acid synthesis
Define antibiotic
substance naturally produced by living organisms such as bacteria and fungi and able in dilute solutions to inhibit or kill another microorganism
Define spectrum of activity?
range of activity of an antimicrobial agent/antibiotic has against certain groups of bacteria
Define antimicrobial agent?
chemical substance or agent produced by a microorganism that has the capability of killing or inhibiting the growth of other microoganisms
Define intrinsic?
All members of the species are resistant
Define Acquired?
Not all members are resistant
What is the mechanism of resistance for S. saprophyticus and novobiocin
Intrinsic
What is the mechanism of resistance for S. aureus and methicillin/oxacillin
Aquired
What are the exchange mechanisms for genes?
chromosomal, plasmid, transposon
What are the mechanisms for transfer?
conjugation, transformation
What are the mechanism for expression?
constitutive, inducible
Define Impermeability
decreased accumulation by altered outer membrane porins(channels in cell membranes) or altered transport systems(energy dependent efflux)
Define alterations in target molecules
methylation of ribosomal RNA(plasmid induced), alterations of ribosomes(prevent binding), altered penicillin binding proteins(PBP) target for most beta-lactam antimicrobials, single step or multi-step
Define enzymatic inactivation
Beta lactamases(plasmid mediated, chromosomal, extended spectrum), chloramphenicol acetyltransferases, aminoglycoside modifying enzymes
Define autonomous interaction
indifferent, no change
Define Antagonistic interaction
Inhibited when combined
Define synergistic interaction
Enhanced when combined
What antibiotic is Streptococcus pyogenes is universally susceptible to?
Penicillin
Growth medium for susceptibility
Mueller Hinton, 3-5mm
What is the pH
7.2-7.4
What is the cation concentration?
NaCl, Mg, Ca
What are the incubation requirements?
ambient air, 16-18hr @37
What is the inoculum density?
1.5x10^8 (.5mcF) final of 5x105 in broth
Outline the principle, procedure and interpretation of the disk diffusion test
Zone of inhibition determines susceptibility
Take 3-5 isolated colonies and mix into broth, then streak for lawn of growth on plate, place antimicrobial disks on plate, incubate, measure diameter and compare to CLSI charts
Outline the principle, procedure, and interpretation for E testing
Plastic strip contains gradient of antimicrobial
Use MacFarland standard, streak for lawn of growth, place strips on plate, incubate, read for MIC at lowest concentration where no growth occured
Outline the principle, procedure, and interpretation of broth dilution testing.
Different dilutions of antimicrobials in broths to determine MIC
Uses modified MacFarland in broths, lowest concentration with growth is MIC
Outline the principle, procedure, and interpretation of MIC/MBC and MID/MBD testing.
Two-fold dilutions used to determine MIC or MID, the negatives of which can be used to test MBC or MBD,
MIC/MID: Two-fold dilutions with increasing concentrations of antimicrobial to determine the MIC
MBC/MBD: plate the tubes with no visual growth to determine what concentration inhibits 99.9% of growth
What is the standard for susceptibility?
Agar dilution
What test helps to ID resistant MRSA?
Mueller hinton and NaCl and oxacillin
What test helps to ID ESBL?
Cephalosporin and cephalosporin + Clavulanic acid
What test helps ID CREs?
Hodge Test
What clindamycine resistance?
D test
What is ESBL
Extended spectrum beta lactamases
What is CRE?
Carbapenem resistant enterics
What is KPC?
klebeslla pnemoneae carbapenem
What is ARHI?
Ampicillin resistant Haemophilus influenzae