Antimictobials Flashcards
1
Q
Colistin
A
Polymyxin E
- Targets cell membrane
- Active against gram - and non growing
- low resistance
- high toxicity
- limited to topicals
- resistance due to an enzyme that modifies lipid A
2
Q
Daptomycin (cubicin)
A
- Targets cytoplasmic membrane resulting in depolarization
- bactericidal
- active only against gram + (MRSA, VRSA, and VRE)
- resistance due to accumulation of mutations in different genes rather than a single mutation
3
Q
Beta lactams
A
- largest class of cell wall inhibitors
- only active against growing cells
- penicillins
- cephalosporins
- carbapenems
- monobactams
4
Q
Anti pseudomonals
A
- Ticarcillin and clavulanate/beta lactam and beta lactamase inhibitor
- Piperacillin and tazobactam
5
Q
Ampicillin
A
- Aminopenicillin
- increased activity against gram -
6
Q
Amoxicillin
A
Aminopenicillin
- increased activity against gram -
- greater oral bioavailability
7
Q
Methicillin
A
- semi synthetic
- decreased susceptibility to beta lactamase
- acid sensitive/can’t be given orally
- never used
8
Q
Nafcillin
A
- semi synthetic
- beta lactamase resistance
- give Naf for Staph
- acid stable; absorbed from GI
9
Q
Oxacillin
A
- semi synthetic
- beta lactamase resistance
- acid stable
10
Q
MRSA resistance
A
- acquisition of unique gene (mecA) encoding a unique PBP (PBP2A
- confers resistance to all bets lactam antibiotics
11
Q
1st generation cephalosporins
A
- narrow spectrum
- mostly gram positive with a few gram negatives
- cephalexin, cefazolin, cephalothin, cefadroxil
12
Q
2nd generation cephalosporins
A
- expanded spectrum
- better gram negative and some anaerobes
- cefoxitin, cefotetan, cefaclor, cefonicid
13
Q
3rd generation cephalosporins
A
- broad spectrum
- even better gram negative
- cefoperazone, ceftazidime, ceftriaxone, cefotaxime
14
Q
4th generation cephalosporins
A
- extended spectrum
- broad spectrum but not active against enterococci or anaerobes
- relatively resistant to beta lactamase
- cefepime
15
Q
5th generation cephalosporins
A
- active against MRSA, streptococcus, and several gram negatives including klebsiella
- ceftaroline
- prodrug that gets metabolized to active form
16
Q
Carbapenems
A
- imipenem
- meropenem
- widely used and broadest spectrum of beta lactams
- not active against MRSA and VRE
- resistance due to production of carbapenamase, efflux pumps, and porin change/loss
17
Q
Monobactams
A
- very narrow spectrum; active only against gram negative aerobes
- aztreonam
18
Q
Carbapenem resistance
A
- production of carbapenamase
- resistance in gram negative: klebsiella, acinetobactor, and pseudomonas
19
Q
Glycopeptides
A
- bind rapidly and irreversibly to the D-alanyl-D-alanine terminus
- inhibits transport across cell membrane and cross linking or parallel peptidoglycan chains
- vancomycin, bacitracin, teicoplanin
- gram negative resistance because too large to pass through outer membrane
20
Q
Vancomycin resistance
A
- substitution of terminal D-alanine with D-lactate and won’t bind vancomycin
21
Q
New drugs to treat VRSA
A
- daptomycin
- linezolid (zyvox)
- synercid
22
Q
Lipoglycopeptides
A
- newer derivatives of glycopeptides that have a tail that anchors them in the cell membrane
- telavancin, dalbavancin, and oritavancin
23
Q
Bacitracin
A
- cell wall inhibitor (inhibits translocation of peptidoglycan precursors)
- relatively toxic (restricted to topicals)
- most active against gram positive
- often combined with polymyxin and an aminoglycoside (neomycin)
24
Q
Fosfomycin
A
- cell wall inhibitor (inhibits formation of cytoplasmic subunits)
- used for single dose treatment of UTIs
25
Cycloserine
- cell wall inhibitor (inhibits translocation and cross linking)
- anti TB, but NOT first choice
26
Rifampin
- inhibits DNA dependent RNA polymerase
27
Antimicrobials that target 30s subunit
Tetracyclines and amnioglycosides
28
Tetracycline
- reversibly bind 30s ribosomal subunit, which inhibits binding and aminoacly tRNA to the A site
- bacteriostatic
- broad spectrum that includes both gram negative and positive
- effective against mycoplasma pneumoniae (which is important because don't have cell wall), rickettsia, chlamydia (both of which are obligate intracellular pathogens), and borrelia (Lyme disease)
29
Minocyclin
- Tetracyline
- reversibly bind 30s ribosomal subunit, which inhibits binding and aminoacly tRNA to the A site
- bacteriostatic
- broad spectrum that includes both gram negative and positive
- effective against mycoplasma pneumoniae (which is important because don't have cell wall), rickettsia, and chlamydia (both of which are obligate intracellular pathogens)
30
Doxycline
- Tetracycline
- reversibly bind 30s ribosomal subunit, which inhibits binding and aminoacly tRNA to the A site
- bacteriostatic
- broad spectrum that includes both gram negative and positive
- effective against mycoplasma pneumoniae (which is important because don't have cell wall), rickettsia, and chlamydia (both of which are obligate intracellular pathogens)
31
Tetracycline resistance
- acquisition of exogenous DNA that encodes proteins involved in the active efflux of the antibiotic
- these proteins are designated Tet
- derivatives of tetracycline such as minocyline do not bind Tet and therefore not pumped out as efficiently
32
Tigecycline
- semisynthetic glycylcycline that binds 30s subunit and inhibits protein synthesis
- less susceptible to removal by efflux pumps
33
Aminoglycosides
- binds irreversibly to 30s ribosomal subunit and prevent formation of the 70s initiation complex
- bactericidal
- relatively broad spectrum and used to treat gram negative and gram positive
- often combined with cell wall inhibitors to increase uptake
- streptomycin, gentamicin, kanamycin, tobramycin, neomycin, and amikacin
34
Spectinomycin
- closely related aminoglycoside
- binds reversibly within 30s ribosome
- bacteriostatic
35
Aminoglycoside resistance
- intrinsic resistance due to variations in membrane porins
| - acquired resistance due to modifying enzymes that alter the antibiotic so it can't bind ribosomal target
36
Chloramphenicol
- targets 50s subunit
- inhibits peptidyl transferase and thereby prevents formation of the peptide bond
- bacteriostatic with broad spectrum
- relatively toxic and used primarily for topical purposes, particularly eye drops
- resistance due to production of enzyme that modifies the antibiotic: chloramphenicol acetyltransferase
37
Targets 50s and inhibits translocation
Macrolides, lincosamides, and streptogamins
38
Erythromycin
- macrolide
- bind 50s and inhibit translocation of growing peptide
- only effect proteins being actively synthesized and therefor bacteriostatic
39
Azithromycin
- macrolide
- bind 50s and inhibit translocation of growing peptide
- only effect proteins being actively synthesized and therefore bacteriostatic
40
Clarithromycin
- macrolide
- bind 50s and inhibit translocation of growing peptide
- only effect proteins being actively synthesized and therefore bacteriostatic
41
Macrolides
- erythromycin, azithromycin, and clarithromycin
- broad spectrum with good activity against gram positive infections
- good for patients allergic to penicillin
42
Clindamycin
- lincosamide
- active against staphylococci and anaerobic gram negative bacilli
- generally inactive against aerobic gram negatives
- activity against anaerobes accounts for its association with pseudomembraneous colitis
43
MLS resistance (macrolides, lincosamides, and streptogamins)
- methylation of the bacterial 23s rRNA of the 50s (modification of the target)
- intrinsic resistance in gram negative due to MLS low membrane permeability b/c highly hydrophobic compounds
44
Synercid
- streptogramin
- bactericidal
- bind 50s subunit and inhibits translocation
45
Oxazolidinones
- protein synthesis inhibitor which bind 50s subunit and block formation of the 70s initiation complex. This prevents formation of the first peptide bond
- Linezolid (zyvox)
- bacteriostatic
46
Zyvox resistance
- single point mutation in the gene encoding 23s RNA
47
Tedizolid
- 2nd generation oxazolidinone
- active against linezolid resistant gram positive cocci
- active against most MRSA
48
Nalidixic acid
- quinolone
- targets nucleic acid synthesis by interfering with DNA supercoiling
- binds DNA topoisomerase, most notably DNA gyrase
49
Norfloxacin
- fluoroquinolone
| - binds DNA gyrase
50
Ciprofloxacin
- fluoroquinolone
| - binds DNA gyrase
51
Levofloxacin
- fluoroquinolone
| - binds DNA gyrase
52
Quinolones
- broad spectrum, but most active against aerobic, gram negatives
- not very active against anaerobics
- concentrated as much as 20 fold inside phagocytic cells
- resistance due to mutations of DNA gyrase genes leading to reduced binding of antibiotic
53
Rifampicin
- inhibits transcription by binding beta subunit of DNA dependent RNA polymerase
- good for gram positive and mycobacteria
- gram negative intrinsically resistant due to outer membrane
- cornerstone drug for TB
- resistance due to point mutation in gene coding beta subunit of polymerase which inhibits binding. For this reason, always use with one or more antibiotics
54
Metronidazole
- targets DNA via free radicals which causes double stranded breaks
- not commonly used because no activity against aerobic or facultatively anaerobic bacteria
- important for treatment of anaerobic infections including pseudomembranous colitis (clostridium difficile)
55
Sulfonamides
- Antimetabolite which inhibits synthesis of tetrahydrofolate
- competitive inhibitor of DHPS
- bacteriostatic
- bactericidal when used in combination with trimethoprim
- resistance due to decreased permeability and some gram positives (enterococcus) utilize exogenous thymine to bypass the need for THF
- acquired high level resistance for a specific chromosomalgene that encodes DHFR or DHPS enzymes with altered active sites that are not bound by antibiotic. May arise from chromosomal mutations, but more often found on plasmids and/or transposons
56
Trimethoprim
- Antimetabolite which inhibits synthesis of tetrahydrofolate
- competitive inhibitor of DHFR
- bacteriostatic
- bactericidal when used in combination with sulfonamide
- resistance due to decreased permeability and some gram positives (enterococcus) utilize exogenous thymine to bypass the need for THF
- acquired high level resistance for a specific chromosomalgene that encodes DHFR or DHPS enzymes with altered active sites that are not bound by antibiotic. May arise from chromosomal mutations, but more often found on plasmids and/or transposons
57
Unasyn
- ampicillin + sulbactam
58
Augmentin
- amoxicillin + clavulanate
59
Timentin
- ticarcillin + clavulanate
60
Zosyn
- piperacillin + tazobactam
61
Cilastatin
Peptidase inhibitor
62
Fidaxomicin (dificid)
- macrolide
| - expensive, but also used for C. difficile
63
Isoniazid
- cell wall inhibitor
| - anti mycobacterial
64
buy AT 30, CELLS at 50
30s subunit
- Aminoglycosides
- Tetracycline
50s subunit
- Chloramphenicol or Clindamycin
- Erythromycin
- Lincomycin or cLindamycin
- Linezolid
- Streptogramins (Synercid)
65
Isoniazid
Anti mycobacterial
66
Ethambutol
Anti mycobacterial
67
Cycloserine
Anti mycobacterial
68
Ethionamide
Anti mycobacterial
