Kinder Abx Flashcards

1
Q

Common Infectious Agents: Outpatient

A
Streptococcus pneumoniae
Mycoplasma pneumoniae
Haemophilus influenzae
Chlamydophila pneumoniae
Respiratory viruses
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2
Q

Common Infectious Agents: Inpatient (non-ICU)

A
S. pneumoniae
M. pneumoniae
C. pneumoniae
H. influenzae
Legionella spp
Aspiration
Respiratory viruses
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3
Q

Common Infectious Agents: Inpatient (ICU)

A
S. pneumoniae
Staphylococcus aureus
Legionella spp
Gram-negative bacilli
H. influenzae
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4
Q

Infecting Organisms & Disease States

A

Underlying bronchopulmonary disease:
H. influenzae
Moraxella catarrhalis
+ S. aureus during an influenza outbreak

Chronic oral steroids or severe underlying bronchopulmonary disease, alcoholism, frequent antibiotic use:
Enterobacteriaceae
Pseudomonas aeruginosa

Classic aspiration pleuropulmonary syndrome in alcohol/drug overdose or in seizures with gingival disease or esophageal motility disorders:
Anaerobes

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5
Q

Drug-resistant S. pneumoniae Risk Factors

A
Age < 2 years or > 65 years
B-lactam use within previous 3 months
Alcoholism
Immunosuppressive illness or therapy
Exposure to child at day care
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6
Q

Antimicrobial Coverage for Outpatient, Previously Healthy Pts

A
Macrolide PO (azithromycin, clarithromycin)
Doxycycline PO
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7
Q

Antimicrobial Coverage for Outpatient, At Risk for DRSP

A

Respiratory fluoroquinolone PO (levofloxacin, moxifloxacin, gemifloxacin)
B-lactam PO [high dose amoxicillin or amoxicillin-clavulanate preferred (alternates: ceftriaxone, cefuroxime)] PLUS a macrolide PO

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8
Q

Antimicrobial Coverage for Outpatient, Regions with high rate (> 25%) of macrolide resistant S. pneumoniae

A

Consider alternatives

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9
Q

Antimicrobial Coverage for Inpatient, non-ICU

A

Respiratory FQ IV or PO (levofloxacin, moxifloxacin)

B-lactam IV (ceftriaxone, cefotaxime, or ampicillin preferred) PLUS macrolide IV (azithromycin)

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10
Q

Antimicrobial Coverage for Inpatient, ICU

A

B-lactam IV (ceftriaxone, cefotaxime, or ampicillin/sulbactam preferred) PLUS azithromycin IV OR a respiratory FQ (levofloxacin, moxifloxacin)

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11
Q

Modified Empiric Regimen for Pseudomonas risks

A

Structural lung disease (bronchiectasis)
Repeated COPD exacerbations
Frequent corticosteroid and/or antibiotic use
Prior antibiotic therapy

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12
Q

Pseudomonas Risks Treatments

A
Anti-pseudomonal B-lactam IV (piperacillin-tazobactam, cefepime, imipenem, meropenem) PLUS either ciprofloxacin or levofloxacin
Or B-lactam PLUS:
An aminoglycoside (gentamicin) AND azithromycin
An aminoglycoside AND anti-pseudomonal fluoroquinolone
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13
Q

CA-MRSA risks

A

End-stage renal disease (dialysis)
Injection drug abuse
Prior influenza
Prior antibiotic use (especially FQ)

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14
Q

CA-MRSA Treatments

A

Add vancomycin IV or linezolid

Panton-Valentine leucocidin necrotizing pneumonia: add clindamycin or use linezolid

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15
Q

Pseudomonas as MDR

A

Resistance caused by multiple efflux pumps
Decreased expression of outer membrane porin channel
Increasing resistance to: piperacillin, ceftazidime, cefepime, imipenem, meropenem, aminoglycosides, fluoroquinolones

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16
Q

Other MDRs

A

Klebsiella intrinsically resistant to ampicillin and can acquire resistance to cephalosporins and aztreonam  ESBL production
Enterobacter high frequency of developing resistance to cephalosporins during treatment
These bacteria may carry plasmid mediated AmpC-type enzymes (ESBL) which are carbapenem susceptible but CONCERNED about resistance
May become resistant by loss of an outer membrane porin

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17
Q

MRSA & DRSP

A

MRSA
> 50% of ICU infections caused by S. aureus methicillin resistant
PBPs with reduced affinity for B-lactams
Concern for linezolid resistance but still rare
DRSP
Altered PBP
ALL MDR strains in US currently susceptible to vancomycin and linezolid

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18
Q

Empiric Therapy – Early Onset

A

Potential pathogens:
S. pneumoniae
H. influenzae
MSSA
Sensitive gram-negative: E. coli, K. pneumoniae, Enterobacter spp, Proteus spp, Serratia marcescens
Treatment:
Ceftiaxone OR FQ (levofloxacin, moxifloxacin, ciprofloxacin) OR ampicillin/sulbactam OR ertapenem

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19
Q

Empiric Therapy – Late Onset

A
Potential pathogens (MDR):
P. aeruginosa
K. pneumoniae (ESBL+)
Acinetobacter
MRSA
Treatment:
Antipseudomonal cephalosporin (cefepime, ceftazidime) OR antipseudomonal carbapenem (imipenem, meropenem) OR       B-lactam/B-lactamase inhibitor (piperacillin-tazobactam) 
PLUS 
Antipseudomonal FQ (ciprofloxacin, levofloxacin) OR aminoglycoside (amikacin, gentamicin, tobramycin) 
PLUS 
Linezolid OR vancomycin
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20
Q

Streptococcus pneumoniae

A

Non-resistant
Penicillin G, amoxicillin
Resistant
Chosen on basis of susceptibility: cefotaxime, ceftriaxone, levofloxacin, moxifloxacin, vancomycin, linezolid

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21
Q

Haemophilus influenzae

A

Non-B-lactamase producing
Amoxicillin
B-lactamase producing
2nd or 3rd generation cephalosporin, amoxicillin/cluvulanate

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22
Q

Mycoplasma pneumoniae

A

Macrolide (azithromycin, clarithromycin), tetracycline (doxycycline)

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23
Q

Chlamydophila pneumoniae

A

Macrolide (azithromycin, clarithromycin), tetracycline (doxycycline)

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24
Q

Chlamydophila psittaci

A

Doxycycline

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25
Q

Legionella spp

A

Fluoroquinolone, azithromycin, doxycycline

26
Q

Enterobacteriaceae (Klebsiella, E. coli, Enterobacter, Proteus)

A

3rd or 4th generation cephalosporin, carbapenem (if ESBL producer)

27
Q

Pseudomonas aeruginosa

A

Antipseudomonal B-lactam PLUS ciprofloxacin, levofloxacin, or an aminoglycoside

28
Q

Anaerobe (aspiration): Bacteroides, Fusobacterium, Peptostreptococcus

A

B-lactam/B-lactamase inhibitor, clindamycin

29
Q

Staphylococcus aureus

A

Methicillin-sensitive
Antistaphylococcal penicillin (nafcillin, oxacillin, dicloxacillin)
Methicillin-resistant
Vancomycin or linezolid

30
Q

Pneumocystis jiroveci (P. carinii pneumonia)

A

Trimethoprim/sulfamethoxazole

31
Q

Bordetella pertussis

A

Azithromycin, clarithromycin

32
Q

Influenza virus

A

Oseltamivir, zanamivir

33
Q

Coccidioides spp

A

No treatment necessary if normal host

Itraconazole, fluconazole

34
Q

Histoplasmosis and Blastomycosis

A

Itraconazole

35
Q

Β-Lactams: MOA

A

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

36
Q

Β-Lactams: Resistance

A

Structural difference in PBPs
Decreased PBP affinity for B-lactams
Inability for drug to reach site of action (i.e. gram-negative organisms)
Active efflux pumps
Drug destruction and inactivation by B-lactamases

37
Q

Penicillins: Adverse effects

A
Allergic reactions (0.7-10%)
Anaphylaxis (0.004-0.04%)
Interstitial nephritis (rare)
Nausea, vomiting, mild to severe diarrhea
Pseudomembranous colitis
38
Q

Cephalosporins: Adverse effects

A

1% risk of cross-reactivity to penicillins
Diarrhea
Intolerance to alcohol (disulfram-like reaction due to MTT group of cefotetan)

39
Q

Carbapenems: Adverse effects

A

Nausea/vomiting (1-20%)
Seizures (1.5%)
Hypersensitivity

40
Q

Vancomycin: MOA

A

Inhibits cell wall synthesis binding with high affinity to D-Ala-D-Ala terminal of cell wall precursor units.

41
Q

Vancomycin: Resistance

A

Alteration of D-Ala-D-Ala target to D-alanyl-D-lactate or D-alanyl-D-serine which binds glycopeptides poorly. Intermediate resistance may also occur

42
Q

Vancomycin: Adverse effects

A

Macular skin rash, chills, fever, rash
Red-man syndrome (histamine release): extreme flushing, tachycardia, hypotension
Ototoxicity, nephrotoxicity (33% with initial tr > 20 mcg/mL)

43
Q

Fluoroquinolones: MOA

A

Concentration-dependent, targets bacterial DNA gyrase & topoisomerase IV. Prevents relaxation of positive supercoils

44
Q

Fluoroquinolones: Resistance

A

Mutation in genes encoding DNA gyrase or topoisomerase IV. Active transport out of cell.

45
Q

Fluoroquinolones: Adverse effects

A

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)

46
Q

30S Inhibitors

A

Aminoglycosides
ADRs: ototoxicity, nephrotoxicity, neuromuscular block

Tetracyclines
ADRs: GI, superinfections with C. difficile, photosensitivity, teeth discoloration

47
Q

50S Inhibitors

A

Macrolides
ADRs: GI, hepatotoxicity, arrhythmia

Clindamycin
ADRs: diarrhea, C. difficile, skin rash

Streptogramins
ADRs: infusion pain and phlebitis

Linezolid
ADRs: myelosuppression, headache, rash

48
Q

Neurominidase Inhibitors

A

Oseltamivir (PO), zanamivir (INH)

MOA: analogs of sialic acid, interferes with release of progeny influenza virus from infected host cell

49
Q

Neurominidase Inhibitors: Adverse effects

A

Oseltamivir – nausea, vomiting, abdominal pain (5-10%), headache, fever, diarrhea, neuropsychiatric effects
Approved for children ≥ 1 year

Zanamivir – cough, bronchospasm, decrease in pulmonary function (reversible), nasal/throat discomfort, not recommended in underlying airway disease
Approved for children ≥ 7 years

50
Q

M2 Channel Blockers

A

Amantadine (PO), rimantadine (PO)

MOA: block M2 proton ion channels of virus inhibiting uncoating of viral RNA within host cell
Active against influenza A only

51
Q

M2 Channel Blockers: Adverse effects

A

GI (nausea, anorexia), CNS (nervousness, insomnia, light-headedness), severe behavioral changes, delirium, agitation, seizures

52
Q

HSV & VZV

A

Acyclovir (PO, IV, topical), valacyclovir (PO)
MOA: three phosphorylation steps for activation, first step via virus specific thymidine kinase. Inhibits DNA synthesis:
Competition with deoxyGTP for DNA polymerase –> binds DNA template irreversible complex
Chain termination following incorporation into viral DNA

53
Q

HSV & VZV

A

Therapeutic use: genital herpes (treatment, prophylaxis, suppression), varicella, HSV encephalitis, neonatal HSV treatment
Adverse effects: nausea, diarrhea, headache

54
Q

CMV

A

Ganciclovir (PO, IV), valgancyclovir (PO)
MOA: acyclic guanosine analog, requires activation by triphosphorylation before inhibiting DNA polymerase.
Termination of DNA elongation

55
Q

CMV

A

Therapeutic use: CMV retinitis treatment, CMV prophylaxis

Adverse effects: myelosuppression, nausea, diarrhea, fever, peripheral neuropathy

56
Q

Azole Antifungals

A

MOA: inhibits fungal cytochrome P450, reducing production of ergosterol
Selective toxicity due to greater affinity for fungal rather than human cytochrome

57
Q

Azole Antifungals: Therapeutic use

A

Wide spectrum of activity against Candida spp, blastomycosis, coccidiodomycosis, histoplasmosis, and even Aspergillus (itraconazole, voriconazole)

58
Q

Azole Antifungals: Adverse effects

A

Minor GI upset, abnormalities in liver enzymes

Drug interactions!!

59
Q

Azole Antifungals: drugs

A

Fluconazole (Diflucan) PO, IV
PK: water soluble, good CSF penetration, high PO bioavailability ~96%

Itraconazole PO
PK: drug absorption increased by food and low gastric pH

Voriconazole (Vfend) PO, IV
PK: well absorbed, bioavailability > 90%
ADRs: visual changes, photosensitivity

60
Q

Amphotericin B

A

Polyene macrolide antibiotic
MOA: binds ergosterol and changes permeability of cell by forming pores in cell membrane

PK:
Insoluble in water, variety of lipid formulations available, poorly absorbed PO, t1/2 15 days, only 2-3% of blood level reaches CSF

Therapeutic use: broadest spectrum of activity, useful in life-threatening infections but very toxic

Adverse effects: infusion related (fever, chills, vomiting, headache) and cumulative toxicity (renal damage)

61
Q

Echinocandins

A

Caspofungin, micafungin, anidulafungin (IV)
MOA: inhibits synthesis of B(1-3)-glucan, disrupts fungal cell wall, and causes cell death

Therapeutic use: Candida and Aspergillus
Adverse effects: minor GI, flushing