Antibiotics

Question 1

Antibacterials/Antimicrobials vs Antibiotics

Answer 1

• work on bacteria & other microorganisms
• work only on bacteria

Question 2

Bacteriostatic vs Bactericidal

Answer 2

• inhibit growth
• kill

Question 3

Mechanisms of Antibiotic Action

Answer 3

• inhibit bacterial cell wall synthesis
• alter membrane permeability
• inhibit protein synthesis
• inhibit bacterial RNA/DNA synthesis
• interferes with intracellular metabolism

Question 4

Healthcare-acquired infections (HAIs)

Answer 4

• CLABSI
• CAUTI
• SSI
• Ventilator-associated pneumonia

commonly Cdiff, staph aureus, Ecoli, pseudomonas aeruginosa, klebsiella pneumoniae

Question 5

Antibiotic Resistance

Answer 5

• abx taken unnecessarily
• abx taken incorrectly

Question 6

Abx combo effects

Answer 6

• additive –> effects of both meds increased
• antagonistic –> bactericidal vs bacteriostatic; may reduce desired effects
• potentiated –> one potentiates other w/ no increased effects of potentiating abx
• synergism –> effect of both is increased exponentially

additive –> 2+2 = 4, synergistic –> 2+2=10

Question 7

General adverse reactions to abx

Answer 7

• allergic reactions/hypersensitivity
• superinfections (candida, cdiff/CDAD, mrsa, vre, etc.)
• organ toxicity (ear, liver, kidneys)
• GI distress
• headache, dizziness
• lab changes

Question 8

Superinfections

Answer 8

• secondary infection when normal flora is killed
• often Candidasis, C-Diff, MRSA, VRE
• usually found in/on mouth, skin, resp tract, GU tract, intestines

VRE - vancomycin resistant enterococci

Question 9

Spectrums & C&S testing

Answer 9

• narrow spectrum –> primarily effective against one bacteria type
• broad spectrum –> effective against gram +/-, often before specific organism identified
• Culture & Sensitivity (C&S) –> should be sampled directly from site if possible; done to determine specific organism and gram + or -
• C&S should be done before any abx given

Question 10

Penicillins

Answer 10

• beta-lactam ring structure
• inhibits bacterial cell wall synthesis
• static and cidal, depending on dose
• four types –> basic, broad-spectrum, penicillinase-resistant, and extended-spectrum
• SE: hypersensitivity, anaphylaxis, superinfection, tongue discoloration, stomatitis, GI distress, CDAD, liver impairment

Question 11

Basic penicillins

Answer 11

• G & V (rare, IM only)
• narrow spectrum
• for gram + and a few -
• treats anthrax, tetanus, diphtheria, endocarditis, resp infx, syphilis
• poorly absorbed PO

strep, clostridium species; neisseria, staph species

Question 12

Broad-spectrum penicillins

Answer 12

• Amoxicillin
• gram + and -
• treats infx of resp, skin, intra-abdominal, GU, otitis media, sinusitis

Ecoli, haemophilus influenzae, shigella dysenteriae, proteus mirabilis, salmonella spp.

Question 13

Penicillinase-resistant penicillins

Answer 13

• Dicloxacillin sodium
• gram +
• treats endocarditis, meningitis, bacteremia, skin, resp infx

penicillinase-producing staph spp. (penicillinase is an enzyme that some bacteria naturally produce that beraks down beta-lactam ring structure)

Question 14

Extended-spectrum penicillins

Answer 14

• gram +/-
• treats resp, intra-abdomial, skin infx

pseudomonas aeruginosa, proteus spp., serratia spp., klebsiella pneumoniae, enterobacter spp., acinetobacter spp.

Question 15

Beta-lactamase inhibitors

Answer 15

• inhibit bacterial beta-lactamases, extending their antimicrobial spectrum
• not given alone –> combined w/ penicillinase-sensitive penicillin

Question 16

Cephalosporins

Answer 16

• Ceftriaxone
• inhibit bacterial cell wall synthesis
• cidal
• treats resp, GU, skin, bone, joint infx
• 1st, 2nd, 3rd, 4th, 5th generations
• SE: anaphylaxis, superinfection, headache, dysgeusia, GI distress, CDAD, bleeding, seizures, nephrotoxicity, SJS, elevated liver enzymes
• Interacts with alcohol (disulfiram-like rxn), uricosurics (decrease ceph. excretion)

disulfiram reaction –> flushing, dizziness, headache, n/v, muscle cramps

Question 17

1st gen cephalosporins

Answer 17

• mostly gram +, some -
• staph, strep, klebsiella, proteus, salmonella, shigella spp., Ecoli

Question 18

2nd gen cephalosporins

Answer 18

• gram +/-
• staph, strep, klebsiella, proteus, salmonella, shigella, enterobacter spp., Ecoli, haemophilus influenzae, neisseria gonorrhoeae, neisseria meningitidis

Question 19

3rd gen cephalosporins

Answer 19

• gram +/-
• increased resistance to destruction by beta-lactamases
• staph, strep, klebsiella, proteus, salmonella, shigella, enterobacter, serratia, acinetobacter spp., haemophilus influenzae, Ecoli, neisseria gonorrhoeae, neisseria meningitidis, pseudomonas aeruginosa

Question 20

4th gen cephalosporins

Answer 20

• gram +/-
• highly resistant to destruction by beta-lactamases
• staph, strep, klebsiella, proteus, spp., Ecoli, pseudomonas aeruginosa

Question 21

5th gen cephalosporins

Answer 21

• gram +/-
• highly resistant to destruction by beta-lactamases
• staph, strep, klebsiella, proteus spp., MRSA, Ecoli, pseudomonas aeruginosa

Question 22

Macrolides

Answer 22

• Azithromycin, erythromycin, clarithromycin
• binds to 50S ribosomal subunits and inhibits protein synthesis
• broad spectrum
• most gram +, some -
• static, cidal w/ high doses
• treats mild-moderate resp, sinus, skin, soft tissue, GI infections, diptheria, impetigo, STIs
• SE: anaphylaxis, superinfection, tinnitus, ototoxicity, headache, seizures, dysgeusia, tooth discoloration, GI distress, CDAD, nephrotoxicity, hepatotoxicity, SJS
• interactions: increases warfarin, theophylline, carbamazepine levels; fluconazole, ketoconazole, itraconazole, verapamil, ciltiazem, and clarithromycin increase erythromycin levels (can cause sudden cardiac death); antacids may decrease azithromycin levels

Question 23

Oxazolidinones

Answer 23

• Linezolid
• inhibits protein synthesis on 50S ribosomal subunit of bacteria
• gram +
• static and cidal (depends on dose)
• treats bacteremia, sepsis, MRSA, VREF, resp, skin infx
• SE: anaphylaxis, seizure, tongue/tooth discoloration, GI distress, peripheral neuropathy, headache, pancytopenia, CDAD, serotonin syndrome, SJS

Question 24

Lincosamides

Answer 24

• Clindamycin
• inhibits bacterial protein synthesis
• most gram + (staph aureus, anaerobics)
• static and cidal (depends on dose)
• treats gyne, acne, bacteremia, septicemia, MRSA, resp, intra-abdominal, skin, bone, joint infx
• SE: anaphylaxis, superinfections, xerosis, dysgeusia, glossitis, stomatitis, GI distress, CDAD, pancytopenia, SJS
• clindamycin and lincomycin are incompatible with aminophylline, phenytoin, barbiturates, and ampicillin

Question 25

Glycopeptides

Answer 25

• Vancomycin
• inhibits cell wall synthesis
• gram + (MRSA)
• cidal
• treats resp, skin, bone/joint infx, bacteremia, septicemia, endocarditis, MRSA, CDAD
• draw peaks & troughs
• SE: anaphylaxis, superinfection, red neck/red man syndrome, disulfiram-like rxn to alcohol, GI distress, peripheral edema, oto/nephrotoxicity, CDAD, SJS

red neck/red man –> IV too rapid, severe hypotension, red blotching of face, neck, chest, extremities

Question 26

Ketolides

Answer 26

• Telithromycin
• structurally related to macrolides
• blocks bacterial protein synthesis
• treats community-acquired pneumonia, MRSA, strep. pneumoniae, haemophilus influenzae
• SE: anaphylaxis, dizziness, headache, visual disturbances, GI distress, dysgeusia, CDAD, hepatotoxicity, exacerbation of myasthenia gravis
• interactions?

Question 27

Lipopeptides

Answer 27

• Daptomycin
• inhibits bacterial protein, DNA/RNA synthesis
• gram + staph aureus, MRSA
• treats complicated skin infx, septicemia, endocarditis
• SE: anaphylaxis, superinfection, insomnia, dizziness, anemia, bleeding, chest pain, GI distress, peripheral neuropathy, hypo/hyper tension/kalemia/glycemia, rhabdomyolysis
• interacts w/ statins, warfarin

Question 28

Tetracyclines

Answer 28

• Doxycycline
• inhibits protein synthesis
• broad spectrum, gram +/-
• treats helicobacter pylori, MRSA, acne, anthrax, plague, gingivitis, cholera, STIs, skin, urinary, resp infx
• SE: anaphylaxis, superinfections, photosensitivity, diplopia, discoloration of permanent teeth (kids), stomatitis, glossitis, GI distress, CDAD, oto/hepato/nephrotoxicity, pancytopenia, SJS
• interacts w/ milk products, antacids, oral contraceptives, penicillins, aminoglycosides

break down into toxic by products when expired

Question 29

Glycylcycline

Answer 29

• Tigecycline
• blocks protein synthesis in bacterial cells
• static
• synthetic tetracyclines
• treats staph aureus, Ecoli, strep pyogenes, klebsiella pneumoniae, clostridium perfringens, complicated skin and intra-abdominal infx
• SE: anaphylaxis, superinfection, photosensitivity, headache, dizziness, insomnia, GI distress, anemia, hyperglycemia, hypokalemia, CDAD, SJS

Question 30

Aminoglycosides

Answer 30

• Gentamicin
• inhibits bacterial protein synthesis
• cidal
• gram - Ecoli, proteus, pseudomonas spp.
• treats serious resp, skin, urinary, bone/joint, intra-abdominal infx, plague (streptomycin), tularemia (streptomycin), bacteremia, septicemia, endocarditis, meningitis, hepatic encephalopathy, preoperative bowel antiseptic
• peak and trough levels
• SE: anaphylaxis, superinfection, seizures, photosensitivity, anemia, stomatitis, GI distress, oto/nephro/neurotoxicity, CDAD, SJS
• interactions: penicillins decrease aminoglycoside effectiveness; increased action of oral anticoags; ethacrynic acid w/ aminoglycosides may lead to ototoxicity

Question 31

Fluoroquinolones

Answer 31

• Ciprofloxacin, levofloxacin
• interferes w/ enzyme DNA gyrase needed to synthesize bacterial DNA
• gram +/-, S. pneumoniae, S. aureaus, H. influenzae, P. aeruginosa, salmonella, shigella spp.
• cidal, broad spectrum
• treats anthrax, skin, soft tissue, bone, joint, GU, intra-abdominal, resp infx
• SE: anaphylaxis, superinfection, photosensitivity, eye damage, visual disturbances, GI distress, dysgeusia, tendinitis, tendon rupture, CDAD, SJS, nephrotoxicity

Question 32

Sulfonamides

Answer 32

• Trimethoprim-sulfamethoxazole
• inhibits bacterial synthesis of folic acid
• static
• gram -, proteus, klebsiella, chlamydia spp., Ecoli
• treats otitis media, meningitis, malaria, resp, urinary infx
• SE: anaphylaxis, photosensitivity, GI distress, stomatitis, insomnia, tinnitus, crystalluria, renal failure, blood dyscrasias, SJS
• interacts with antacids

folic acid is essential for bacterial cell growth, but not naturally synthesized in humans, so selective for bacteria

Question 33

Nitromidazoles

Answer 33

• disrupts DNA and protein syntheses in bacteria and protozoa
• H. pylori, clostridium, giardia, gardnerella, prevotella, peptococcus spp., trichomonas vaginalis protozoa
• treats CDAD, amebiasis, giardiasis, trichomoniasis, bacterial vaginosis, acne, meningitis, gyne, skin, intra-abdominal, resp infx
• SE: anaphylaxis, superinfection, headache, dizziness, insomnia, weakness, dry mouth, dysgeusia, GI distress, tongue/tooth discoloration, peripheral neuropathy, seizures, leukopenia, disulfiram-like rxn, SJS