Anti-Microbials Flashcards
(131 cards)
1
Q
Penicillin G, V–form and type of antibiotic
A
- Penicillin G–IV and IM form
- Penicillin V–oral form
- prototype beta lactam antibiotics
2
Q
penicillin G, V–mechanism
A
- D-Ala-D-Ala structural analog
- bind penicillin binding proteins (transpeptidases)
- block transpeptidase cross linking of peptidoglycan in cell wall
- activate autolytic enzymes
3
Q
penicillin G, V–use
A
- mostly used for gram + organisms–S. pneumoniae, S. pyogenes, Actinomyces
- also used for gram - organisms–mainly N. meningitidis
- also used for spirochetes–T. pallidum
- bactericidal for gram + cocci, gram + rods, gram - cocci, and spirochetes
- penicillinase sensitive
4
Q
penicillin G, V–toxicity
A
- hypersensitivity reactions
- direct Coombs + hemolytic anemia
5
Q
penicillin G, V–resistance
A
- penicillinase in bacteria (a type of beta lactamase) cleaves beta lactam ring
6
Q
name the penicillinase sensitive penicillins
A
- amoxicillin
- ampicillin
- aminopenicillins
7
Q
penicillinase sensitive penicillin–mechanism
A
- same as penicillin
- wider spectrum
- “AMinoPenicillins are AMPed up penicillin”
- penicillinase sensitive
- also combine with clavulanic acid to protect against destruction by beta lactamase
8
Q
penicillinase sensitive penicillins–oral bioavailability
A
- “AmOxicillin has greater Oral bioavailability than ampicillin”
9
Q
penicillinase sensitive penicillins–use
A
- extended spectrum penicillin
- H. influenzae
- H. pylori
- E. coli
- Listeria monocytogenes
- Proteus mirabilis
- Salmonella
- Shigella
- enterococci
- coverage:
- ampicillin amoxicillin HHELPSS kill entercocci
10
Q
penicillinase sensitive penicillins–toxicity
A
- hypersensitivity reactions
- rash
- pseudomembranous colitis
11
Q
penicillinase sensitive penicillins–mechanism of resistance
A
- penicillinase in bacteria (a type of beta lactamase) cleaves beta-lactam ring
12
Q
name the penicillinase-resistant penicillins
A
- dicloxacillin
- nafcillin
- oxacillin
13
Q
penicillinase-resistant penicillins–mechanism
A
- same as penicillin
- narrow spectrum
- penicillinase resistant b/c bulky R group blocks access of beta-lactamase to beta-lactam ring
14
Q
penicillinase-resistant penicillins–use
A
-
S. aureus–except MRSA: resistant b/c of altered penicillin binding protein target site
- “use naf (nafcillin) for staph”
15
Q
penicillinase-resistant penicillins–toxicity
A
- hypersensitivity rxns
- interstitial nephritis
16
Q
name the antipseudomonal penicillins
A
- piperacillin
- ticarcillin
17
Q
antipseudomonal penicillins–use
A
- Pseudomonas spp. and gram - rods
- susceptible to penicillinase
- use with beta lactamase inhibitors
18
Q
antipseudomonal penicillins–toxicity
A
- hypersensitivity rxns
19
Q
name the beta lactamase inhibitors
A
- Clavulanic Acid
- Sulbactam
-
Tazobactam
- CAST
20
Q
what are beta lactamase inhibitors often taken with? Why?
A
- often added to penicillin to antibiotics
- to protect the antibiotic from destruction by beta-lactamase (penicillinase)
21
Q
cephalosporins (gen I-IV)–mechanism
A
- beta lactam drugs that inhibit cell wall synthesis but are less susceptible to penicillinases
- bactericidal
22
Q
what are the organisms not covered by 1st-4th generation cephalosporins? what is the exception?
A
-
LAME
- Listeria
- Atypicals–Chlamydia, Mycoplasma
- MRSA
- Enterococci
- exception: ceftaroline–5th generation cephalosporin which covers MRSA
23
Q
1st gen cephalosporins:
name 2
what organisms do they cover?
A
- cefazolin
- cephalexin
- gram + cocci
- Proteus mirabilis
- E. coli
-
Klebsiella pneumoniae
- “PEcK”
24
Q
why would cefazolin be used prior to surgery?
A
- to prevent S. aureus wound infections
25
2nd gen cephalosporins:
name 3
what organisms do they cover?
* ce**fa**clor
* ce**fox**itin
* ce**fur**oxime
* "**Fa**ke **fox fur**"
* gram + cocci
* ***H.** influenzae*
* ***E**nterobacter aerogenes*
* ***N**eisseria spp.*
* ***S**erratia marcesvens*
* ***P**roteus mirabilis*
* ***E.** coli*
* ***K****lebsiella pneumoniae*
* *"***HENS PEcK**"
26
3rd gen cephalosporins:
name 3
what organisms do they cover?
* ceftriaxone
* meningitis
* gonorrhea
* disseminated Lyme dz
* cefotaxime
* ceftazidime
* *Pseudomonas*
* serious gram - infections resistant to other beta lactams
27
4th gen cephalosporins:
name 1
what organisms do they cover?
* cefepime
* gram - organisms
* with increased activity against *Pseudomonas* and gram + organisms
28
5th gen cephalosporins:
name 1
what organisms do they cover?
* ceftaroline
* broad gram + and gram - organism coverage, including MRSA
* does NOT cover *Pseudomonas*
29
cephalosporins--toxicity
* hypersensitivity rxns
* autoimmune hemolytic anemia
* disulfiram like rxn
* vitamin K deficiency
* exhibit cross reactivity with penicillins
* inc nephrotoxicity of aminoglycosides
30
cephalosporins--mechanism of resistance
* structural change in penicillin binding proteins--transpeptidases
31
name the carbapenems
* imipenem
* meropenem
* ertapenem
* doripenem
* newer carbapenems include ertapenem (limited *Pseudomonas* coverage) and doripenem)
32
imipenem--mechanism
* (carbapenems)
* imipenem is broad spectrum, beta lactamase resistant carbapenem
33
what is imipenem always administered with? why?
* cilastatin (inhibitor of renal dehydropeptidase I) to decrease inactivation of drug in renal tubules
* with imipenem, "the kill is **lastin**' with ci**lastin**"
34
carbapenems--use
* gram + cocci
* gram - rods
* anaerobes
* wide spectrum but significant side effects limit use to life threatening infections or after other drugs have failed
* meropenem--dec risk of seizures and is stable to dehydropeptidase I
35
carbapenems--toxicity
* GI distres
* skin rash
* CNS toxicity at high plasma levels
* seizures
36
name the monobactam
* aztreonam
37
monobactam (aztreonam)--mechanism
* less susceptible to beta lactamases
* prevents peptidoglycan cross linking by binding to penicillin-binding protein 3
* synergistic with aminoglycoside
* no cross allergenicity with penicillins
38
monobactam (aztreonam)--use
* gram - rods only
* no activity against gram + rods or anaerobes
* for penicillin allergic patients and those with renal insufficiency who cannot tolerate aminoglycosides
39
monobactams--toxicity
* usually nontoxic
* occasional GI upset
40
vancomycin--mechanism
* inhibits cell wall peptidoglycan formation by binding D-ala-D-ala portion of cell wall precursors
* bactericidal against most bacteria
* bacteriostatic against *C. difficile*
* not susceptible to beta lactamases
41
vancomycin--use
* gram + bugs only
* serious, multidrug-resistant organisms, including MRSA, *S. epidermidis*, sensitive *Enterococcus* species, *Clostridium difficile*
* oral dose for pseudomembranous colitis
42
vancomycin--toxicity
* well tolerated in general but **NOT** trouble free
* **N**ephrotoxicity
* **O**totoxicity
* **T**hrombophlebitis
* diffuse flusing--red man syndrome
* can largely prevent by pretreatment with antihistamines and slow infusion rate
43
vancomycin--mechanism of resistance
* occurs in bacteria via amino acid modification of **D-ala-D-ala** to D-ala-D-lac
* "Pay back **2 D-ala**s (dollars) for **van**dalizing (**van**comycin)"
44
protein synthesis inhibitors--mechanism
* specifically, target smaller bacterial ribosome (70S, made of 30S and 50S subunits), leaving human ribosome (80S) unaffected
45
name the 30S and 50S inhibitors
* **30**S inhibitors
* **A** = **A**minoglycosides [bactericidal]
* **T** = **T**etracyclines [bacteriostatic]
* **50**S inhibitors
* **C** = **C**hloramphenicol, **C**lindamycin [bacteriostatic]
* **E** = **E**rythromycin (macrolides) [bacteriostatic]
* **L** = **L**inezolid [variable]
* "Buy **AT 30, CCEL** (sell) at **50**"
46
name the aminoglycosides
* **G**entamicin
* **N**eomycin
* **A**mikacin
* **T**obramycin
* **S**treptomycin
* "**Mean"** (a**min**oglycoside) **GNATS** ca**NNOT** kill anaerobes"
47
aminoglycosides--mechanism
* bactericidal
* irreversible inhibition of initiation complex thru binding of the 30S subunit
* can cause misreadin gof mRNA
* also block translocation
* require O2 for uptake
* therefore ineffective against anaerobes
48
aminoglycosides--use
* severe gram - rod infections
* synergistic with beta lactam antibiotics
* neomycin for bowel surgery
49
aminoglycosides--toxicity
* **N**ephrotoxicity
* **N**euromuscular blockage
* **O**totoxicity
* especially when used with loop diuretics
* **T**eratogen
* "**Mean**" (aminoglycoside) **GNATS** ca**NNOT** kill anaerobes"
50
aminoglycosides--mechanism of resistance
* bacterial transferase enzymes inactivate the drug by acetylation, phosphorylation, or adenylation
51
name the drug classes that block cell wall synthesis by inhibition of peptidoglycan cross linking?
* penicillinase sensitive penicillins
* penicillinase resistant penicillins
* antipseudomonals
* cephalosporins
* carbapenems
* monobactams
52
name the drugs that prevent cell wall synthesis by inhibiting peptidoglycan synthesis
* vancomycin
* bacitracin
53
name the drugs that block nucleotide synthesis by inhibiting folic acid synthesis (involved in methylation)
* sulfonamides
* trimethoprim
54
name the drug that damages DNA via free radicals
* metronidazole
55
name the drug that blocks mRNA synthesis
* rifampin
56
name the drug classes that block DNA gyrase
* fluoroquinolones
* quinolone
57
name the drugs that block protein synthesis at the 50S subunit
* chloramphenicol
* clindamycin
* linezolid
* macrolides
* streptogramins
58
name the drugs that block protein synthesis at the 30S subunit
* aminoglycosides
* tetracyclines
59
name the tetracyclines
* tetracycline
* doxycycline
* minocycline
60
tetracyclines--mechanism
* bacteriostatic
* bind to 30S and prevent attachment of aminoacyl tRNA
* limited CNS penetration
61
how is doxycycline eliminated, and in which patients can it be used?
* fecally eliminated
* can be used in patients with renal failure
62
what should you avoid when taking tetracyclines, and why?
* milk (Ca2+), antacids (Ca2+ or Mg2+), or iron containing preparations
* b/c divalent cations inhibit drugs' absorption in the gut
63
tetracyclines--use
* *Borrelia burgforferi*
* *M. pneumoniae*
* drugs ability to accumulate intracellularly makes them very effective against *Rickettsia* and *Chlamydia*
* used to treat acne
64
tetracyclines--toxicity
* GI distress
* discoloration of teeth and inhibition of bone growth in children
* photosensitivity
65
what is a contraindication for taking tetracyclines?
* pregnancy
66
tetracyclines--mechanism of resistance
* dec uptake or inc efflux out of bacterial cells by plasmid encoded transport groups
67
chloramphenicol--mechanism
* blocks peptidyltransferase at 50S ribosomal subunit
* bacteriostatic
68
chloramphenicol--use
* meningitis (*Haemophilus influenzae, Neisseria meningitidis, Stretococcus pneuomoniae*) and Rocky Mountain Spotted Fever (*RIckettsia rickettsii*)
* limited use owing to toxicities but often still used in developing countries b/c of low cost
69
chloramphenicol--toxicity
* anemia--dose dependent
* aplastic anemia--dose independent
* gray baby syndrome--in premature infants b/c they lack liver UDP glucuronyl transferase
70
chloramphenicol--mechanism of resistance
* plasmid encoded acetyltransferase inactivates the drug
71
clindamycin--mechanism
* blocks peptide transfer (translocation) at 50S ribosomal subunit
* bacteriostatic
72
clindamycin--use
* anaerobic infections (ie. *Bacteroides* spp., *Clostridium perfringens*) in aspiration pneumonia, lung abscesses, and oral infections
* also effective against invasive group A streptococcal infection
73
clindamycin vs. metronidazole
* clindamycin--treats anaerobic infections _above_ the diaphragm
* metronidazole--treats anaerobic infections _below_ the diaphragm
74
name the oxalidinones
* linezolid
75
oxalidinones--mechanism
* inhibit protein synthesis by binding to 50S subunt and preventing formation of the initiation complex
76
oxalidinones--use
* gram + species including MRSA and VRE
77
oxalidinones--toxicity
* bone marrow suppression--especially thrombocytopenia
* peripheral neuropathy
* serotonin syndrome
78
oxalidinones--mechanism of resistance
* point mutation of ribosomal RNA
79
name the macrolides
* azithromycin
* clarithromycin
* erythromycin
80
macrolides--mechanism
* inhibit protein synthesis by blocking translocation ("macro**slides**")
* bind to the 23S rRNA of the 50S ribosomal subunit
* bacteriostatic
81
macrolides--use
* atypical pneumonias--*Mycoplasma, Chlamydia, Legionella*
* STIs--*Chlamydia*
* gram + cocci--streptococcal infections in patients allergic to penicllin
* *B pertussis*
82
macrolides--toxicity
* **MACRO**
* gastrointestinal **M**otility issues
* **A**rrhythmia caused by prolonged QT interval
* acure **C**holestatic hepatitis
* **R**ash
* e**O**sinophilia
* increases serum concentration of theophylline, oral anticoagulants
* clarithromycin and erythromycin inhibit cytochrome P-450
83
macrolides--mechanism of resistance
* methylation of 23S rRNA -binding site prevents binding of drug
84
name the sulfonamides
* sulfamethoxazole (SMX)
* sulfisoxazole
* sulfadiazine
85
sulfonamides--mechanism
* inhibit dihydropteroate synthase, thus inhibiting folate synthesis
* bacteriostatic
* bacteriocidal when combined with trimethoprim
86
sulfonamides--use
* gram +
* gram -
* *Nocardia*
* *Chlamydia*
* SMX for simple UTI
87
sulfonamides--toxicity
* hypersensitivity rxns
* hemolysis if G6PD deficient
* nephrotoxicity--tubulointerstitial nephritis
* photosensitivity
* kernicterus in infants
* displace other drugs from albumin (ie. warfarin)
88
sulfonamides--mechanism of resistance
* altered enzyme (bacterial dihydropteroate)
* decrease uptake
* increase PABA synthesis
89
dapsone--mechanism
* similar to sulfonamides
* but structurally distinct agent
90
dapsone--use
* leprosy (lepromatous and tuberculoid)
* *Pneumocystis jirovecii* prophylaxis
91
dapsone--toxicity
* hemolysis if G6PD deficient
92
trimethoprim--mechanism
* inhibits bacterial dihydrofolate reductase
* bacteriostatic
93
trimethoprim--use
* used in combination with sulfonamides (trimethoprim-sulfamethoxazole [TMP-SMX])
* causes sequential block of folate synthesis
* combination used for UTIs, *shigella*, *Salmonella, Pneuomocystis* *jirovecii* pneuomonia treatment and prophylaxis, toxoplasmosis prophylaxis
94
trimethoprim--toxicity
* megaloblastic anemia
* leukopenia
* granulocytopenia
* may alleviate with supplemental folinic acid
* "**TMP T**reats **M**arrow **P**oorly"
95
name the fluoroquinolones
* ciprofloxacin
* norfloxacin
* levofloxacin
* ofloxacin
* moxifloxacin
* gemifloxacin
* enoxacin
96
fluoroquinolones--mechanism
* inhibit prokaryotic enzymes topoisomerase II (DNA gyrase) and topoisomerase IV
* bactericidal
* must not be taken with antacids
97
fluoroquinolones--use
* gram - rods of urinary and GI tracts (including *Pseudomonas*)
* *Neisseria*
* some gram + organisms
98
fluoroquinolones--toxicity
* GI upset
* superinfections
* skin rashes
* headache
* dizziness
* less commonly, can cause leg cramps and myalgias
* may prolong QT interval
* may cause tendonitis or tendon rupture in people \> 60 years old and in patients taking prednisone
* "fluoroquino**lones** hurt attachments to your **bones**"
99
what are contraindications for fluoroquinolones?
* pregnant women
* nursing mothers
* children \< 18 yo due to possible damage to cartilage
100
fluoroquinolones--mechanism of resistance
* chromosome encoded mutation in DNA gyrase
* plasmid mediated resistance
* efflux pumps
101
daptomycin--mechanism
* lipopeptide that disrupts cell membrane of gram + cocci
102
daptomycin--use
* *S. aureus* skin infections (especially MRSA)
* bacteremia
* endocarditis
* VRE
103
why is daptomycin not used for pneumonia?
* daptomycin avidly binds to and is inactivated by surfactant
104
metronidazole--mechanism
* forms toxic free radical metabolites in the bacterial cell that damage DNA
bactericidal
* antiprotozoal
105
metronidazole--use
* treats:
* ***G**iardia*
* ***E**ntamoeba*
* ***T**richomonas*
* ***G**ardnerella vaginalis*
* **A**naerobes--*Bacteroides, C. difficile*
* used with a proton pump inhibitor and clarithromycin for "triple therapy" against *H. **p**ylori*
* **"**GET GAP** on the **M**etro with **metro**nidazole"
106
metronidazole--toxicity
* disulfiram-like rxn (severe flushing, tachycardia, hypotension) with alcohol
* headache
* metallic taste
107
* M. tuberculosis*
1. prophylaxis
2. treatment
1. Isoniazid
2. **R**ifampin, **I**soniazid, **P**yrazinamide, **E**thambutol
1. **RIPE** for treatment
108
* M. avium-intracellulare*
1. prophylaxis
2. treatment
1. azithromycin, rifabutin
2. more drug resistant than *M. tuberculosis*
1. azithromycin or clarithromycin + ethambutol
2. can add rifabutin or ciprofloxacin
109
* M. leprae*
1. prophylaxis
2. treatment
1. N/A
2. long term treatment with dapsone and rifampin for tuberculoid form
1. add clofazimine for lepramatous form
110
name the rifamycins
* rifampin
* rifabutin
111
rifamycins--mechanism
* inhibit DNA dependent RNA polymerase
112
rifamycins--use
* *Mycobacterium tuberculosis*
* delay resistance to dapsone when used for leprosy
* used for meningococcal prphylaxis and chemoprophylaxis in contacts of children with *Haemophilus influenzae* type B
113
rifamycins--toxicity
* minor hepatotoxicity
* drug reactions--inc cytochrome P-450
* orange body fluids--non hazardous side effect
114
when is rifabutin favored over rifampin and why?
* RIfabutin favored over rifampin in patients with HIV infection due to less cytochrome P-450 stimulation
* "**R**if**amp**in **ramp**s up cytochrome P-450, **but** rifa**but**in does not"
115
rifamycins--mechanism of resistance
* mutations reduce drug binding to RNA polymerase
* monotherapy rapidly leads to resistance
116
Rifampin: 4 things to remember
* **4 R's**
* **R**NA polymerase inhibitor
* **R**amps up microsomal cytochrome P-450
* **R**ed/orange body fluids
* **R**apid resistance if used alone
117
name the 4 antimycobacterial drugs
* Rifamycins--rifampin, rifabutin
* Isoniazid
* Pyrazinamide
* Ethambutol
* Streptomycin
118
Isoniazid--mechanism
* dec synthesis of mycolic acids
* bacterial catalase-peroxidase (encoded by KatG) needed to convert INH to active metabolite
119
Isoniazid--use
* *Mycobacterium tuberculosis*
* this is the only agent used as solo prophylaxis against TB
* also used as monotherapy for latent TB
120
isoniazid--toxicity
* hepatotoxicity
* P-450 inhibition
* drug induced SLE
* vitamin B6 deficiency--peripheral neuropathy, sideroblastic anemia
* **INH I**njures **N**eurons and **H**epatocytes
121
what should be administered with isoniazid?
* puridoxine (vitamin B6)
122
isoniazid--mechanism of resistance
* mutations leading to underexpression of KatG
123
pyrazinamide--mechanism
* mechanism uncertain
* prodrug that is converted to the active compound pyrazinoic acid
* works best at acidic pH (ie. in host phagolysosomes)
124
pyrazinamide--use
* *Mycobacterium tuberculosis*
125
pyrazinamide--toxicity
* hyperuricemia
* hepatotoxicity
126
ethambutol--mechanism
* dec carbohydrate polymerization of mycobacterium cell wall by blocking arabinocyltransferase
127
ethambutol--use
* *Mycobacterium tuberculosis*
128
ethambutol--toxicity
* **optic** neuropathy (red-green color blindness)
* pronouce "**eye**thambutol"
129
streptomycin--mechanism
* interferes with 30S component of ribosome
130
streptomycin--use
* *Mycobacterium tuberculosis* (2nd line)
131
streptomycin--toxicity
* tinnitus
* vertigo
* nephrotoxicity
