Antiobiotics Flashcards
which drugs inhibit cell wall synth?
Vancomycin, Bacitracin, Penicillins, Cephalosporins, carbapenems
Ampicillin
Aminopencillin
extended spectrum, often administered with B-lactamase inhibitor
Gram +: streptococcus and staphylococcus (not MRSA)
Gram -: H. influenza, E. Coli, Proteus miribalis
Randoms: Listeria monocytogenes
Use: upper resp. tract infections (of S. pyogenes, S. pneumoniae, H. influenzae), sinusitis, otitis media, enterococcal infections
Amoxicillin
Aminopenicillin - just PO
extended spectrum, often administered with B-lactamase inhibitor
Gram +: streptococcus and staphylococcus (not MRSA)
Gram -: H. influenza, E. Coli, Proteus miribalis
Randoms: Listeria monocytogenes
Use: upper resp. tract infections (of S. pyogenes, S. pneumoniae, H. influenzae), sinusitis, otitis media, enterococcal infections
Piperacillin
Anti-Psudeomonal penicilin
Extended spectrum:
Gram pos: streptococcus and staphylococcus (not MRSA)
Gram negs: H. influenza, E. Coli, Proteus miribalis
Randoms: Listeria monocytogenes
And Extended to more serious gram negatives:
- to Pseudomonas aeruginosa, Enterobacter, and Proteus spp
Therapeutic use: serious gram-negative infections, hospital acquired pneumonia (HAP), immunocompromised patients, bacteremia, burn infections, UTI
.
Cefriaxone
third gen. cephalosporin
Less active against gram positive, but more active against gram negatives.
** active against Enterobacteriaceae (i.e. Klebsiella pneumonia, proteus mirabalis, providencia, serratia) and Haemophilus influenza
Therapeutic use:
DOC for for serious gram-negative infections (Klebsiella, Enterobacter, Proteus, Providencia, Serratia, Haemophilus),
- Ceftriaxone DOC for all forms of gonorrhea and severe Lyme’s disease, meningitis
Ceftazidime
third gen. cephalosporin
Less active against gram positive, but more active against gram negatives.
- active against Enterobacteriaceae (i.e. Klebsiella pneumonia, proteus mirabalis, providencia, serratia) and Haemophilus influenza
- ** ACTIVE AGAINST PSEUDOMONAS **
Use:
DOC for for serious gram-negative infections (Klebsiella, Enterobacter, Proteus, Providencia, Serratia, Haemophilus)
- Ceftazidime covers Pseudomonas
Cefepime
Fourth generation Cephalosporin
Spectrum: extends beyond third-generation (some gram +, enterobacteria gram negs), useful in serious infections in HOSPITALIZED PATIENTS. Effective against Pseudomonas
Therapeutic use: empirical treatment of nosocomial infections (infections aqd in hospital)
meropenem
carbapenem
- Very broad spectrum
Covers: aerobic and anaerobic, gram positives, Enterobacteriaceae, Pseudomonas, Acinetobacter
Therapeutic use: UTI, lower respiratory tract infection (LRTI), intra-abdominal, gynecological, SSTI, bone and joint infections – very broad spectrum, should be used VERY sparingly, only In very serious infections!!!
Ertapenem
carbapenem
- Very broad spectrum
Covers: aerobic and anaerobic, gram positives, Enterobacteriaceae, Pseudomonas, Acinetobacter
Therapeutic use: UTI, lower respiratory tract infection (LRTI), intra-abdominal, gynecological, SSTI, bone and joint infections – very broad spectrum, should be used VERY sparingly, only In very serious infections!!!
ampicillin-sublactam
B-lactamase inhibitor
MOA: prevent destruction of B-lactam antibiotics
S. Serratia spp P. Pseudomonas aeruginosa I. Indole + (Acinetobacter, Morganella, Proteus [not mirabilis]) C. Citrobacter spp E. Enterobacter cloacae
amoxicillin-clavulanic acid
B-lactamase inhibitor
MOA: prevent destruction of B-lactam antibiotics
S. Serratia spp P. Pseudomonas aeruginosa I. Indole + (Acinetobacter, Morganella, Proteus [not mirabilis]) C. Citrobacter spp E. Enterobacter cloacae
Piperacillin-tazobactam
B-lactamase inhibitor
MOA: prevent destruction of B-lactam antibiotics
S. Serratia spp P. Pseudomonas aeruginosa I. Indole + (Acinetobacter, Morganella, Proteus [not mirabilis]) C. Citrobacter spp E. Enterobacter cloacae
Vancomycin
glycopeptide
MOA: inhibits cell wall synthesis binding with high affinity to D-Ala-D-Ala terminal of cell wall precursor units
Spectrum: broad gram-positive coverage
S. aureus (including MRSA), S. epidermidis (including MRSE), Streptococci, Bacillus, Corynebacterium spp, Actinomyces, Clostridium
Therapeutic use: osteomyelitis, endocarditis, MRSA, Streptococcus, enterococci, CNS infections, bacteremia, orally for Clostridium difficile (only oral indication for Vanc)
ciproflaxacin
fluoroquinolone
MOA: targets bacterial DNA gyrase & topoisomerase IV. Prevents relaxation of positive supercoils
Spectrum: E. coli, Salmonella, Shigella, Enterobacter, Campylobacter, Neisseria, Pseudomonas aeruginosa, S. aureus (not MRSA), limited coverage of Streptococcus spp.
Therapeutic use: UTI, prostatitis, STI (chlamydia, Neisseria gonorrhoeae), traveler’s diarrhea, shigellosis, bone, joint, SSTI infections, diabetic foot infections
Levoflaxacin
Fluoroquinolone
MOA: targets bacterial DNA gyrase & topoisomerase IV. Prevents relaxation of positive supercoils
Spectrum: E. coli, Salmonella, Shigella, Enterobacter, Campylobacter, Neisseria, Pseudomonas aeruginosa, S. aureus (not MRSA), limited coverage of Streptococcus spp.
Therapeutic use: UTI, prostatitis, STI (chlamydia, Neisseria gonorrhoeae), traveler’s diarrhea, shigellosis, bone, joint, SSTI infections, diabetic foot infections
Moxifloxacin
Fluoroquinolone
MOA: targets bacterial DNA gyrase & topoisomerase IV. Prevents relaxation of positive supercoils
Spectrum: E. coli, Salmonella, Shigella, Enterobacter, Campylobacter, Neisseria, Pseudomonas aeruginosa, S. aureus (not MRSA), limited coverage of Streptococcus spp.
** this one is metabolized by the liver, so it does not need to be dose adjusted for those with renal failure!
Therapeutic use: UTI, prostatitis, STI (chlamydia, Neisseria gonorrhoeae), traveler’s diarrhea, shigellosis, bone, joint, SSTI infections, diabetic foot infections
Gentamicin
Aminoglycoside
MOA: binds 30S
Spectrum: aerobic gram-negative bacteria, limited action against gram-positive, synergistic bactericidal effects in gram-positive with cell wall active agent (like Beta lactam or Vanc)
Therapeutic use: UTI (not uncomplicated), used if resistance to other agents, seriously ill patients, pneumonia (infective against S. pneumoniae and anaerobes), HAP, peritonitis, synergy in bacterial endocarditis, tobramycin inhalation in CF
Doxycycline
tetracycline/glycylcylclines
Spectrum: wide range of aerobic/anaerobic gram + and gram - (as well as Rickettsia, Coxiella burnetii, Mycoplasma pneumoniae, Chlamydia spp, Legionella, atypical mycobacterium, Plasmodium, Borrelia burgdorferi (Lyme’s disease), Treponema pallidum (syphilis)
** Pseudomonas not covered ***
Therapeutic use: CAP, atypical CAP coverage, community acquired SSTIs, community acquired MRSA, acne, Rickettsial infections (Rocky Mountain Spotted Fever), Q fever, anthrax
Azithromycin
macrolide/ketolide
MOA: inhibits translocation of 50s subunit
Use: : respiratory tract infections (due to coverage of S. pneumoniae, H. influenzae, and atypicals: Mycoplasma, Chalmydophilia, Legionella), alternative for otitis media, sinusitis, bronchitis, and SSTIs. Pertussis, gastroenteritis, H. pylori, Mycobacterial infections
Clindamycin
Lincosamide
MOA: binds 50S subunit
Spectrum: pneumococci, S. pyogenes, viridans Streptococci, MSSA, anaerobes (B. fragilis)
(all gram negs are resistant)
Use:
SSTIs, necrotizing SSTIs, lung abscesses, anaerobic lung and pleural space infections, topically for acne vulgaris
Linezolid
oxazalidinone:
MOA: inhibits synth binding P site of 50S
Spectrum: : gram-positive Staphylococcus (MSSA, MRSA, VRSA), Streptococcus (penicillin resistant S. pneumoniae), enterococci (VRE), gram-positive anaerobic cocci, gram-positive rods (Corynebacterium, L. monocytogenes)
Use: VRE faecium (SSTI, UTI, bacteremia), nosocomial pneumonia caused by MSSA and MRSA, CAP, complicated/uncomplicated SSTI infections
Oseltamivir
Antiviral- “Tamiflu”
Flucanazole
Antifungal
Itraconazole
Antifungal
Voriconazole
Antifungal
Empiric Therapy
Provide therapy to a symptomatic patient without identification of infecting organism
Example: initiating antimicrobials for community-acquired pneumonia (CAP) based on knowledge of most likely infecting pathogen
Extended-spectrum:
active against gram-positive bacteria but also against significant number of gram-negative bacteria
Broad-spectrum:
: act on a wide variety of bacterial species, including both gram-positive and gram-negative
MOA of Beta- lactams
i.e. penicillins
B-lactams are structural analogs of D-Ala-D-Ala; they covalently bind penicillin-binding proteins (PBPs), inhibiting the last transpeptidation step in cell wall synthesis
Resistance: through drug destruction and inactivation of B-lactamases
Penicillin
A type of beta-lactam
- effective against gram-positive cocci: narrow spectrum against streptococcus pneumoniae and meningitis
Penicillin
Beta-lactam
Spectrum: highly effective against gram-positive cocci (GPC) but easily hydrolyzed by penicillinase
Therapeutic use: narrow-spectrum, Streptococcus pneumoniae pneumonia and meningitis.
AE’s of penicillins?
- Allergic reactions (0.7-10%)
- Anaphylaxis (0.004-0.04%) – this is rare, and completely CI
- Interstitial nephritis (rare)
- Nausea, vomiting, mild to severe diarrhea
- Pseudomembranous colitis
AE’S of cephalosporins?
1% risk of cross-reactivity to penicillins
Diarrhea
Intolerance to alcohol (disulfram-like reaction due to MTT group of cefotetan)
AE’s of Carbapenems
Adverse effects:
Nausea/vomiting (1-20%)
Seizures (1.5%)
Hypersensitivity
AE’s of glycopeptides?
i.e. vancomycin
Macular skin rash, chills, fever, rash
Red-man syndrome (histamine release): extreme flushing, tachycardia, hypotension
Ototoxicity, nephrotoxicity (33% with initial tr > 20 mcg/mL)
AE’s of fluoroquinolones?
-oxacin
GI 3-17% (mild nausea, vomiting, abdominal discomfort)
CNS 0.9-11% (mild headache, dizziness, delirium, rare hallucinations)
Rash, photosensitivity, Achilles tendon rupture (CI in children)
DON’T USE IN CHILDREN UNLESS TOTALLY NECESSARY!
AE’s of aminoglycosides?
ex. gentamicin
Ototoxicity (may be as high as 25%)
Nephrotoxicity (8-26%)
Neuromuscular block and apnea
AE’s of tetracyclines?
GI (epigastric burning, abdominal discomfort, nausea, vomiting, diarrhea) Superinfections of C. difficile Photosensitivity Teeth discoloration Thrombophlebitis
AE’s of Macrolides/ketolides
Azithromycin
- Arrythmia, QT prolongation
- Hepatotoxicity: CYP3A4 inhibition – prolongs effects of digoxin, warfarin….
AE’s of lincosamides?
clindamycin
GI diarrhea (2-20%) Pseudomembranous colitis (0.01-10%) Due to C. difficile Skin rashes (10%) Reversible increase in aminotransferase activity May potentiate neuromuscular blockade
AE’s of Oxazolidinones
Myelosuppression [anemia, leukopenia, pancytopenia, thrombocytopenia (2.4%)]
Headache
Rash
empiric tx previously healthy pt?
Azithromycin or Doxycycline
empiric tx of outpatients at risk for DRSP?
fluoroquinolone or Beta lactam (ceftriaxone or ampicillin) + Azithromyocin
empiric tx of non ICU inpatient?
levofloxacin/moxifloxacin
or
Beta lactam (ceftriaxone) + azithromyocin
empiric tx of ICU patients?
Beta lactam (ceftraixone or ampicillin) + azithromyocin
or
Beta lactam (ceftriaxone) + levofloxacin/moxifloxacin
NOTE: use aztreonam in case of penicillin allergy (anaphylaxis) for the Beta Lactam
tx of pseudomonas aeruginosa?
anti-pseudomonal B lactam (piperacillin-tazobactam, cefepime, meropenem) + cipro/levofloxacin
OR
B lactam + gentamicin AND azithromycin
OR
B lactam + gentamicin and anti-pseudomonal fluoroquinolone
tx of MRSA?
Vancomycin IV or linezolid
tx of MRSA/necrotizing pneumonia?
clindamyacin or linezolid
what is minimum amount of time to receive Ab?
5 days, though most take it for 7 - 10 days
how long must you tx pseudomonas
at least 8 day course (though 15 is shown to be more effective)
aerobic gram negatives seen in HAP/VAP/HCAP?
P. aeruginosa
E. Coli
K. pneumoniae
Acinetobacter spp
gram positive cocci seen in HAP/VAP?
MRSA - more common in DM, head trauma, those in ICU
oronpharyngeal bugs seen in HAP/VAP?
Viridans
Coagulase-negative staph
Neisseria
corynebacterium
Emperic therapy to early onset pneumonia?
possible pathogens: S. pneumoniae H. influenza MSSA gram negs: E. coli, K. pneumoniae, Enterobacter, Proteus, Serratia
Tx: Ceftiaxone OR FQ OR ampicillin OR ertapenem
Late onset pneumonia or known risk factors for MDR pathogens?
potential pathogens: P. aeruginosa, K. pneumoniae, Actinobacter, MRSA
Tx: Antipseudomonal cephalosporin (Cefepime, ceftazidime) OR antipsuedomonal carbapenem (meropenem) OR B-lactam (piperacillin-tazobactam)
+
Antipsuedomonal FQ (cipro/levofloxacin) OR aminoglycoside (gentamicin)
+
Linezolid or Vanc
Treat for 7 days
tx for strep pneumoniae?
penicillin G or amoxicillin
tx fo Penicillin resistant strep pneumoniae?
ceftriaxone
tx for non beta lactamase producing H. influenzae?
amoxicillin
tx. for beta lactamase producing H. influenzae?
second or third generation cephalosporin or amoxicillin
tx for Mycoplasma pneumoniae?
azithromyocin or doxycycline
tx for Chlamydophila pneumoniae?
azithromyocin or doxycycline
tx. for legionella species?
FQ (cipro/levo/moxifloxacin) or azithromycin
tx for chlamydophila psittaci
tetracycline (i.e. doxycycline)
tx for enterobacteriaceae (klebsiella, E. Coli, Enterobacter, Proteus)
3rd or fourth generation cephalosporin (ceftriaxone, ceftiazidime, cefepime) or carbapenem (meropenem, ertapenem)
tx for pseudomonas aeruginosa?
antipseudomonal B lactam (pipercillin) + cipro/levofloxacin or gentamicin
tx for anaerobic aspiration?
i.e. bacteriodes, fusobacterium, peptostreptococcus = Beta lactam, clindamyacin
tx for methicillin susceptible staph aureus?
penicillin
tx for MRSA?
Vancomyocin or linezolid
tx for bordatella pertussis?
azithromyocin
tx for infleunza virus?
oseltamivir or zanamivir (tamiflu)
tx for histoplasmosis/blastomycosis?
itraconazole
tx for mycobacterium tuberculosis?
Isoniazid + rifampin + ethambutol + pyrazinamide
which drugs bind 30S?
aminoglycosides (gentamicin)
Tetracyclines (Doxycycline)
56 y/o male presents due to fever, chills, productive cough and confusion. gram stain shows abundant neutrophils and gram + dipplococci?
most common is strep pneumoniae* - need empiric coverage
previously healthy patient? recommend azithromycin or doxycycline
which drug binds 50S?
macrolides - azithromycin
lincosamides - clindamycin
oxazolidinones - linezolid
binds DNA gyrase preventing relaxation of DNA supercoids?
fluoroquinolones
blocs protein synth by inhibiting translocation?
macrolides, clindamycin
disrupts cell membrane structure
polmyxins, daptomycin
prevents initiation of protein synth
aminoglycosides, linezolid
what do you treat resistance strep pneumo with high level resistance to penicillin?
Levofloxacin - high resistance should give an HAP Ab
what is mechanism of resistance for strep pneumonia?
alteration of Penicillin binding protein
what bacteria would you see if on a cruise or in a hotel room?
legionella
risk factors for DRSP?
old age >65, B-lactam use within 3 mos, alcoholism, Immunosuppressive illness, exposure to child at day care
Which bug most often uses Beta lactamases as resistance mechanism?
think of as resistance to staph aureus
68 y/o female in ED with hx of productive cough and fever, c/o SOB and sharp pains, was tx with ciprofloxacin for UTI 3 weeks prior, has left lower lobe infiltrate
which regimin is most appropriate if tx with CAP?
CURB-65: confusion, uremia, respiration, low BP- 65? she has two of these (age and increased RR) –> admit as an inpatient to hospital with ddx of CAP
Had been on Cipro in the past - thus tx as you would inpatient non-ICU: ceftriaxone + azithromycin
if had Beta lactam allergy: would give respiratory FQ
what do you use if allergic to Beta lactams with inpatient in ICU?
for ICU patients who are admitted with previous hx of anaphylaxis to penicillin - have to use a beta lactam + FQ /macrolide - this would be an indication for use of aztreonam
USE: aztreonam + FQ/azithromycin
which antimicrobials cover atypicals?
azithromycin, doxycyclines- these are major empiric txs
levofloxacin, moxifloxacin
which drugs do not need to be dose adjusted if prescribed to patients with poor renal fn?
ceftriaxone - this is the only beta lactam thats eliminated half in urine and half in bile and it is not effected by poor renal fn.
moxifloxacin - is the other drug that doesn’t have to be dose adjusted for renal impairement
76 y/o man, post CABG developed fever with increasing O2 demands, high temp, high WBCs, right lower love infiltrate, sputum shows WBC and gram negative bacilli. ddx? Is still on the ventilator….
ventilator associated pneumonia - think pseudomonas aeruginosa (the gram positives you would think of would be staph aureus and MRSA)
tx with piperacillin/tazobactam + gentamicin
55 y/o male with 6 hour hx of bloody nose - unable to stop bleeding, has multiple bruises, INR is 5.8 - was recently prescribed Ab for pneumonia….. chart review shows recent mycoplasma pneumonia…. what is ddx?
ddx? macrolide - thinking of Azithromycin reaction with warfarin (this binds the 50S ribosomal subunit)
CF patient who is 25 that has had increasing yellow green sputum production, showing sx of CF exacerbation - shows staph and psuedomonas. What would empiric therapy be if she has pseudo and MRSA?
patients who are younger than 16: see staph aureus
patients who are over 18: see psuedo aeruginosa
tobramycin + piperacillin/tazobactam + vancomycin
- want to pick two antipseudomonal agents that are sensitive, plus a drug that tx MRSA
8 y/o with CAP. wants to be tx as outpatient. what do you not use?
levofloxacin - achilles rupture, not approved under age 16
doxycycline - teeth discoloration
cefotaxime - only given IV
use amoxicillin or azithromycin
aspiration pneumonia in an 85 y/o - admit for CAP, which beta lactam has anaerobic activity? which drug inhibits protein synth and tx aspiration pneumonia?
- ampicillin/sublactam - ampicillin and amoxicillin are extended spectrum penicillins (they cover anaerobes when combined with beta-lactamases)
- Clindamycin
47 y/o male with RA is maintained on prednisone for 6 years, has fevers, n/s, anorexia, w/l, raises chickens, most likely ddx is?
histoplasma capsulatum - treat with itraconazole which works by inhibiting ergosterol synthetase
voriconazole AE?
visual changes - “see flashing lights” or photophobia/color changes
What Respiratory FQ’s to use?
Use Ciprofloxacin when suspect P aeruginosa
Use levofloaxacin/meoxifloxacin when suspect strep pneumonia, but not pseudomonoas aeruginosa
tx for patients at risk for DRSP?
comorbities, age >65 y/o, age <2 y/o, use of antimicrobials in past 3 mos (Beta lactams), alcoholism, immunosuppression, exposure to child at day care
use levofloxacin or Beta lactam (amoxicillin) + azithromycin
when do you use aztreonam?
when patient has penicillin anaphylaxis but is an inpatient in the ICU (thus will use aztreonam + azithromycin/levofloxacin)
resistance mechanisms of gram + vs gram - organisms?
gram positive: strep resistance due to PBP binding resistance (staph sometimes due to B-lactamases)
gram negative = due to beta lactamases
What maintenance therapy may be initiated that acts as an anti-inflammatory and may decrease the virulence of Pseudomonas aeruginosa?
azithromycin
AIDS pt. with difficulty breathing?
pneumocytstis jirovecii = fungi
tx: preferred is “Bactrim” trimethoprim/sulfamethoxazole
use of penicillinG/penicillin V?
streptococcus and syphilis
use of oxacillin/naficillin?
anti-staph Abs
use of amoxicillin/ampicillin?
“extended spectrum” - covers gram-positive in addition to a few gram-negative organisms, also covers enterococci and Listeria monocytogenes
use of piperacillin?
Bottom-line: serious gram-negative infections (Pseudomonas, Enterobacter, Klebsiella), anaerobes
use of ceftriaxone/ceftazidime?
Bottom-line: less active against gram-positives, much more active against Enterobacteriaceae
use of cefepime?
Bottom-line: good gram-positive in addition to serious gram-negative infections (Pseudomonas)
use of carbapenems?
Bottom-line: very broad spectrum! Aerobic and anaerobic gram-positive and gram-negative bacteria. Ertapenem has inferior activity against Pseudomonas.
use of vancomycin?
Bottom-line: no gram-negative or mycobacterium coverage. Broad gram-positive (MRSA, MRSE, enterococci)
use of FQ’s?
Bottom-line: good gram-negative coverage (ciprofloxacin covers Pseudomonas), MSSA, “respiratory FQ’s” cover Streptococcus spp. (levofloxacin)
use of gentamicin?
no anaerobic coverage (requires 02 dependent transport into bacterial cell), broad aerobic gram-negative coverage (tobramycin most active against Pseudomonas)
use of minocycline/doxycycline?
Bottom-line: wide aerobic and anaerobic gram-positive and gram-negative activity, MRSA, atypical bacteria, Rickettsia, Coxiella burnetii, syphilis. Gap: Pseudomonas.
use of azithromycin?
Bottom-line: aerobic gram-positive cocci and bacilli, atypical organisms, inactive against most gram-negatives (except H. influenzae, N. meningitides, Bordetella pertussis)
use of clindamycin?
Bottom-line: gram-positive S. pyogenes, Streptococci, MSSA, CA-MRSA, anaerobes. No aerobic gram-negative coverage.
use of linezolid?
Bottom-line: gram-positive Staphylococcus (MSSA, MRSA, VRSA), Streptococcus (DRSP), enterococci (VRE), gram-positive anaerobic cocci, gram-positive rods
all drugs that cover pseudomonas?
Piperacillin/tazobactam Ceftazidime Cefepime Meropenem Aztreonam Tobramycin Gentamicin Ciprofloxacin
72 y/o female, presents to ED from nursing home, high temp, high RR, low BP, rales in right lower lobe with right lower lobe infiltrate…what is curb-65 score? what is the treatment for empiric therapy of late onset pnuemonia in this case for HAP?
ddx: HCAP
CURB-65: confusion, respiratory, BP, 65 = 4 - admit to ICU
confusion, BUN>20, RR>30, BP 90/60, age 65
nasal swab shows +MRSA - suspect pneumonia though need sputum or BAL, and blood cultures
tx: ceftazidime/cefepime OR meropenem OR Piperacillin-tazobactam \+ Ciprofloxacin OR Gentamycin \+ Vanc/Linezolid
