Resp 08: Antibiotics

Front 1

What are the methods of antibiotic treatment?

Back 1

- Empiric
- Directed

Front 2

What does "empiric" antibiotic treatment mean?

Back 2

- Initiation of treatment prior to determination of a firm diagnosis
- Typically broad-spectrum
- Should be chosen based on the likely pathogen / diagnosis, patient exposure history, and patient allergy history

Front 3

What does "directed" antibiotic treatment mean?

Back 3

- Treatment based on culture and susceptibility results
- Use the most clinically effective, least toxic, narrowest spectrum, and most cost effective agent
- AKA Drug of Choice
- Drug, dose, route, interval, and duration is disease state and patient specific

Front 4

How do you interpret the MIC?

Back 4

Minimum Inhibitory Concentration:
- Either S (susceptible), I (intermediate), or R (resistant)
- Bug-drug specific (relative to concentrations of drug in body)

Front 5

Is it better to have a lower or higher MIC?

Back 5

Lower Minimum Inhibitory Concentration is better, BUT you can't just pick an antibiotic with the lowest MIC

Front 6

What are the drugs of choice for invasive MSSA infections?

Back 6

- Nafcillin (Oxacillin)
- Cefazolin

Front 7

What are the common undesired implications of antibiotic therapy?

Back 7

- Antibiotic resistance
- Adverse drug events (ADEs)
- Increased health-care costs

Front 8

What are some Adverse Drug Events (ADEs) for antibiotics?

Back 8

- Hypersenstivity / allergy (78% of ED visits d/t Abx)
- Drug side effects (19% of ED visits d/t Abx)
- Clostridium difficile infection
- Antibiotic associated diarrhea / colitis

Front 9

How often are Adverse Drug Events d/t antibiotics?

Back 9

19.3% of drug adverse events are d/t antibiotics

Front 10

What kind of antibiotics have the most Adverse Drug Effects?

Back 10

50% d/t Penicillin and Cephalosporin classes

Front 11

What factors should be considered when selecting an antibiotic?

Back 11

1. Spectrum of coverage
2. Patterns of resistance (at hospital, city, etc)
3. Evidence or track record for specified infection
4. Achievable serum, tissue, or body fluid concentration (eg, CSF or urine)
5. Allergy
6. Toxicity
7. Formulation (IV vs PO); if PO assess bioavailability
8. Adherence / convenience (eg, 2x/day vs 6x/day)
9. Cost

Front 12

What is important to consider before giving a patient an antibiotic besides that which is directly related to the present illness?

Back 12

- Duration of hospitalization, if any
- Co-morbidities
- Prior antibiotic use
- What are the patterns of resistance in your institution

Front 13

What are the most common etiologies of community acquired pneumonia in out-patient setting? (* those that are specific to this patient type)

Back 13

- Streptococcus pneumoniae
- Mycoplasma pneumoniae
- Haemophilus influenzae
- Chlamydophila pneumoniae
- Respiratory viruses (influenza A and B, adenovirus, RSV, parainfluenza)

Front 14

What are the most common etiologies of community acquired pneumonia in in-patient (non-ICU) setting? (* those that are specific to this patient type)

Back 14

- Streptococcus pneumoniae
- Mycoplasma pneumoniae
- Chlamydophila pneumoniae
- Haemophilus influenzae
- Legionella species
* Aspiration
- Respiratory viruses (influenza A and B, adenovirus, RSV, parainfluenza)

Front 15

What are the most common etiologies of community acquired pneumonia in in-patient (ICU) setting? (* those that are specific to this patient type)

Back 15

- Streptococcus pneumoniae
* Staphylococcus aureus
- Legionella species
* Gram-negative bacilli
- Haemophilus influenzae

Front 16

What are the types of "atypical pneumonias"?

Back 16

- Chlamydophila pneumoniae (non-ICU and outpatient)
- Mycoplasma pneumoniae (non-ICU and outpatient)
- Legionella species (in-patient only)

Front 17

How should you treat a previously healthy patient with Community-Acquired Pneumonia as an out-patient?

Back 17

- Macrolide: Azithromycin, Clarithromycin, Erythromycin

- Doxycycline (if macrolide is contraindicated)

Front 18

How should you treat a patient with co-morbidities (uncontrolled COPD, diabetes, heart disease, etc) and Community-Acquired Pneumonia as an out-patient?

Back 18

- α-Pneumococcal Fluoroquinolone: Moxifloxacin, Levofloxacin
- β-lactam + Macrolide (Azithromycin, Clarithromycin)

Front 19

How should you treat a patient without PCN allergy and Community-Acquired Pneumonia as an in-patient (non-ICU)?

Back 19

β-lactam + Macrolide (Azithromycin, Clarithromycin)

Front 20

How should you treat a patient with a PCN allergy and Community-Acquired Pneumonia as an in-patient (non-ICU)?

Back 20

α-Pneumococcal Fluoroquinolone: Moxifloxacin, Levofloxacin

Front 21

How should you treat a patient without PCN allergy and Community-Acquired Pneumonia as an in-patient (ICU)?

Back 21

β-lactam
AND
Macrolide (Azithromycin, Clarithromycin)
OR
α-Pneumococcal Fluoroquinolone (Moxifloxacin, Levofloxacin)

Front 22

How should you treat a patient with a PCN allergy and Community-Acquired Pneumonia as an in-patient (ICU)?

Back 22

α-Pneumococcal Fluoroquinolone (Moxifloxacin, Levofloxacin)
AND
Aztreonam (for G- coverage)

Front 23

How should you treat a patient with Community-Acquired Pneumonia if Pseudomonas is a consideration as an in-patient?

Back 23

α-Pneumococcal, α-Pseudomonal β-lactam:
- Piperacillin-Tazobactam OR
- Cefepime OR
- Meropenem

AND

α-Pseudomonal Fluoroquinolone:
- Ciprofloxacin OR
- Levofloxacin

Front 24

What are the α-Pneumococcal, α-Pseudomonal β-lactams? When are they indicated?

Back 24

- Piperacillin-Tazobactam
- Cefepime
- Meropenem

Used for Community-Acquired Pneumonia if Pseudomonas is a consideration as an in-patient

Front 25

What are the α-Pneumococcal Fluoroquinolones?

Back 25

- Moxifloxacin
- Levofloxacin

Front 26

What are the α-Pseudomonal Fluoroquinolones?

Back 26

- Ciprofloxacin
- Levofloxacin

Front 27

How should you treat a patient with Community-Acquired Pneumonia if MRSA is suspected as an in-patient?

Back 27

Add Vancomycin or Linezolid to plan

Front 28

How should you treat a patient with Community-Acquired Pneumonia if aspiration is suspected as an in-patient?

Back 28

Add Clindamycin to cover oral anaerobes (if initial regimen does not cover anaerobes)

Front 29

In patients treated for Community-Acquired Pneumonia, how often is Pneumonia not actually present?

Back 29

30% of patients

Front 30

If a patient has an abnormal chest x-ray, what other evidence do you need before you treat suspected Community-Acquired Pneumonia with antibiotics?

Back 30

Systemic evidence of inflammation:
- Fever
- WBC
- Sputum production
- Etc

Front 31

What should you do if what you thought was pneumonia turns out to be an alternative diagnosis?

Back 31

Discontinue antibiotics

Front 32

What are the types of β-lactams?

Back 32

- Penicillins
- Cephalosporins
- Carbapenems
- Monobactams
- β-Lactamases

Front 33

What are the types of Carbapenems? What kind of antibiotic are they?

Back 33

- Ertapenem
- Meropenem
- imipenem

- β-lactam antibiotics

Front 34

What are the types of Monobactams? What kind of antibiotic are they?

Back 34

- Aztreonam

- β-lactam antibiotics

Front 35

What are the types of β-lactamases? What kind of antibiotic are they?

Back 35

- Clavulanic Acid
- Sulbactam

- β-lactam antibiotics

Front 36

What are the drugs of choice for Pneumococcus infections?

Back 36

- Cefotaxime (kids)
- Ceftriaxone (adults)

Front 37

What are the β-lactam drugs of choice for Pseudomonas aeruginosa infections?

Back 37

- Piperacillin-Tazobactam
- Ceftazadime
- Cefepime
- Meropenem-Imipenem

- Aztreonam (monobactam)

Front 38

What are the types of Macrolides?

Back 38

- Azithromycin (easy, once/day)
- Clarithyromycin (twice/day)
- Erythromycin (not used much)

Front 39

What are Macrolides (Azithromycin, Clarithromycin) used for?

Back 39

- Respiratory G+ and G- bacteria
- Intracellular atypical pathogens (mycoplasma, chlamydia, legionella)

Front 40

What are α-Pneumococcal and α-Pseudomonal Fluoroquinolones used for besides what is in their names?

Back 40

Intracellular atypical pathogens (Mycoplasma, Chlamydia, Legionella)

Front 41

What are the Tetracycline antibiotics?

Back 41

- Tetracycline (not used much, least efficacious)
- Doxycycline (equally effective as mino)
- Minocycline (more side effects than doxy, but equally effective)

Front 42

What are the Tetracyclines used for?

Back 42

- Wide range of G+ and G- bacteria found in respiratory tract
- Also cover atypical organisms such as chlamydia, mycoplasma, and legionella

Front 43

What are the drugs used for G+ Resistant bacteria (usually referring to MRSA)?

Back 43

- Vancomycin
- Linezolid
- Daptomycin

Front 44

What are the limitations of Vancomycin? What is it indicated for?

Back 44

- Will not cover VRE
- IV formulation only
- Covers most other resistant G+ bacteria

Front 45

What are the limitations of Linezolid? What is it indicated for?

Back 45

- Bone marrow suppression and neuropathy w/ prolonged use
- Drug for resistant G+ bacteria (MRSA)

Front 46

What are the limitations of Daptomycin? What is it indicated for?

Back 46

- Not for use in pneumonia because it is bound by surfactant
- Used for Resistant G+ bacterial (outside of lung infections)

Front 47

What is the typical duration of treatment for Community-Acquired Pneumonia? When is the duration longer?

Back 47

- Minimum of 5 days, up to 7 days
- Longer duration if culture is positive for coagulase-positive Staph or Pseudomonas

Front 48

What criteria must the patient meet before stopping therapy for Community-Acquired Pneumonia?

Back 48

- Afebrile for 48-72 hours
- Breathing w/o supplemental oxygen (unless required for pre-existing disease)
- No more than one clinical instability factor (HR > 100, RR > 24, SBP ≤ 90)

Front 49

What are the risk factors for Multi-Drug Resistant Organisms (MDROs) in Health Care Associated Pneumonia (HCAP)?

Back 49

- Current hospitalization ≥ 5 days
- Hospitalization in acute care hospital for ≥ 2 days within past 90 days
- Resident of nursing home or long-term care facility
- Recipient of recent IV antibiotic therapy, chemotherapy, or wound care within past 30 days
- Chronic dialysis within 30 days
- Family member w/ multi-drug resistant pathogen

Front 50

How should you treat a patient without risk factors for Multi-Drug Resistant Organisms (MDROs) with Health Care Associated Pneumonia (HCAP)?

Back 50

Limited Spectrum Abx Therapy:
- Ceftriaxone OR
- Ampicillin-Sulbactam OR
- Ertapenem OR
- Fluoroquinolone

Front 51

How should you treat a patient with risk factors for Multi-Drug Resistant Organisms (MDROs) with Health Care Associated Pneumonia (HCAP)?

Back 51

Broad Spectrum Abx Therapy:

α-Pseudomonal β-lactam

AND

α-Pseudomonal FQ OR Aminoglycoside

AND

Vancomycin or Linezolid if MRSA suspected

Front 52

What is often responsible for pneumonia in a patient w/ an early HIV infection?

Back 52

Streptococcus pneumoniae

Front 53

What is often responsible for pneumonia in a patient w/ a late HIV infection?

Back 53

- Pneumocystis jirovecii
- Non-Tuberculous mycobacteria
- Histoplasma

Front 54

What is often responsible for pneumonia in a patient w/ a transplantation (bone marrow or solid organ)?

Back 54

- Cytomegalovirus
- Respiratory syncytial virus
- Aspergillus
- Mucormycosis

Front 55

What is often responsible for pneumonia in a patient w/ exposure to birds?

Back 55

- Parrots: Chlamydophila psittaci
- Poultry: Avian influenza

Front 56

What is often responsible for pneumonia in a patient w/ exposure to rabbits?

Back 56

Francisella tularensis

Front 57

What is often responsible for pneumonia in a patient w/ exposure to farm or parturient animals?

Back 57

Coxiella burnetti (Q fever)

Front 58

What is often responsible for pneumonia in a patient who has recently travelled to SW United States?

Back 58

- Coccidioides
- Hantavirus

Front 59

What is often responsible for pneumonia in a patient w/ structural lung disease (cystic fibrosis, COPD, bronchiectasis)?

Back 59

- Pseudomonas aeruginosa
- Staphylococcus aureus
- Non-tuberculous mycobacteria
- Aspergillus

Front 60

Case: 49 yo white male w/ hx of HTN and hyperlipidemia presents w/ 3 days of cough, chills, malaise, body aches, and fever to 102.5. He has no known medical allergies.
BP 110/70, T 101.0, RR 26.
Crackles at left lung base and CXR reveals corresponding pneumonia. Patient reports that he is unable to sleep because of cough and has never felt as bad as he presently feels.

What is the appropriate assessment/treatment of this patient?

Back 60

Patient should be treated as an out-patient w/ Azithromycin (Macrolide)

Front 61

What scale can you use to determine the recommendation for pneumonia treatment / mortality?

Back 61

CURB-65:
- Confusion = 1
- BUN > 19 mg/dL = 1
- RR ≥ 30 = 1
- SBP < 90 mmHg or DBP ≤ 60 mmHg = 1
- Age ≥ 65 years = 1

Front 62

What CURB-65 score is associated with a low-risk pneumonia and can be treated at home?

Back 62

0 or 1

Front 63

What CURB-65 score is associated with pneumonia that should be treated with a short-inpatient stay or closely observed out-patient?

Back 63

2

Front 64

What CURB-65 score is associated with severe pneumonia and the patient should be admitted to the ICU?

Back 64

> 3

Front 65

Case: 77 yo female presents to ED w/ dyspnea, fever, hypoTN, and mental status change. She lives at home and has been in relatively good health until this presentation.
T 103, BP 88/60, P 110, R 34, SaO2 88% on RA, improves to 99% on 4L NC
Crackles in left lung base. CXR shows left lower lobe infiltrate. WBC of 2.3, BUN of 33, Creatinine of 1.3.

Based on above presentation, what is the most appropriate course of action?

Back 65

- Based on CURB-65 score she should be admitted to ICU for severe pneumonia
- Begin fluid resuscitation
- IV Ceftriaxone (β-lactam) and Moxifloxacin (α-Pneumococcal FQ)

(Azithromycin could be substituted for Moxifloxacin too)

Front 66

What are the reasons for antibiotic overuse?

Back 66

Patient Concerns:
- Want clear explanation
- Green nasal discharge
- Need to return to work

Physician Concerns:
- Patient expects antibiotic
- Diagnostic uncertainty
- Time pressure

Front 67

Which type of infection has the best use of antibiotics in terms of bacterial prevalence is high relative to antibiotic prescription?

Back 67

Otitis Media

Front 68

What are the most common reasons for antibiotic treatment failure?

Back 68

- Wrong diagnosis
- Undrained focus of infection
- Foreign body
- Secondary infection
- Antibiotic resistance

Front 69

What are the long-term effects of being on an antibiotic?

Back 69

40% still have resistant strains after 5 months (so then if they get the same antibiotic within that time, it will have a higher failure rate)

Front 70

What are the effects of misused antibiotics?

Back 70

Leads to unnecessary adverse drug events (more ED visits d/t adverse rxns, ↑ risk of C. difficile, ↑ cost)

Front 71

What kind of respiratory system infections are caused by viruses?

Back 71

- Bronchitis
- Colds
- Flu
- Most coughs
- Most ear infections
- Most sore throats
- Stomach flu (viral gastroenteritis)

Front 72

What kind of respiratory system infections are caused by bacteria?

Back 72

- Bladder infections
- Wound and skin infections
- Some ear infections
- Strep throat
- Severe sinus infections lasting > 2 weeks

Front 73

What are the instructions for appropriate usage of antibiotics?

Back 73

- Finish entire course
- Do not borrow another person's antibiotics
- Do not use expired antibiotics

Front 74

What is the most common organism responsible for outpatient treated CAP in older patients and those with significant underlying disease?

Back 74

Streptococcus pneumoniae

Front 75

What is the most common organism responsible for outpatient treated CAP in patients < 50 yo with no co-morbidities?

Back 75

Mycoplasma pneumoniae

Front 76

How do you treat CAP in outpatient setting for a healthy patient w/ no use of anti-microbials within the past 3 months?

Back 76

- Macrolide: Azithromycin, Clarithromycin
- Doxycycline

Front 77

How do you treat CAP in outpatient setting for a patient w/ co-morbidities or use of anti-microbials within the past 3 months?

Back 77

- Respiratory (α-pneumococcal) fluroquinolone: Levofloxacin or Moxifloxacin
OR
- β-lactam (amoxicillin or w/ clavulanic acid, cefuroxime, cefpodoxime) + Macrolide

Front 78

What is the most common cause of acute sinusitis? How should it be treated?

Back 78

Viruses account for 90-98% of all cases

Treat w/:
- Anti-histamines
- NSAIDs
- Oral decongestants
- Cough suppressant
- Nasal spray w/ decongestant

Front 79

What are the most common causes of acute bacterial rhinosinusitis (ABRS)?

Back 79

- 38% S. pneumoniae
- 36% H. influenzae
- 16% Moraxella catarrhalis
- 13% Staph aureus
- 4% Other Streptococcus species

Front 80

What symptoms would make you think a patient has acute bacterial rhinosinusitis (ABRS)?

Back 80

- Persistent and not improving for ≥ 10 days
- Severe and > 3-4 days
- Double sickening (start w/ viral infection, got better, then got worse again probably d/t bacterial super-infection)

Front 81

How should you treat acute bacterial rhinosinusitis (ABRS)?

Back 81

Initial Empirical therapy:
* Amoxicillin-Clavulanate bid x 14 days = Augmentin

β-Lactam Allergy:
- Doxycycline
- Levofloxacin
- Moxifloxacin

Failure of Initial Therapy:
- Levofloxacin
- Moxifloxacin

Front 82

What are the most common primary diagnoses associated w/ S. aureus related hospitalizations?

Back 82

1. Cellulitis and Abscess*
2. Device-associated
3. Post-op infection
4. Osteomyelitis
5. Diabetes mellitus

Front 83

How should you manage a MRSA skin / soft tissue infection?

Back 83

1. Cutaneous abscess: incision and drainage (primary treatment)

2. Antibiotic therapy recommended for abscesses w/:
- Severe or extensive disease
- Rapid progression
- Co-morbidities or immuno-suppression
- Abscess in area difficult to drain
- Lack of response to I&D

Front 84

What antibiotics should you use to treat a MRSA skin / soft tissue infection?

Back 84

Outpatient empiric coverage of CA-MRSA in cellulitis:
- Clindamycin
- TMP-SMX
- Doxycycline or Minocycline
- Linezolid

Inpatient complicated SSTI empiric therapy:
- IV Vancomycin
- IV Daptomycin
- IV or PO Linezolid
- IV or PO Clindamycin

Front 85

How should you manage recurrent MRSA skin / soft tissue infections?

Back 85

- Keep draining wounds covered
- Hand and personal hygiene
- Avoid sharing personal items
- Environmental hygiene
- Decolonization may be considered if recurrent SSTI despite wound care and hygiene OR ongoing transmission in household members or other close contacts despite wound care and hygiene

Front 86

How do you decolonize a recurrent MRSA skin / soft tissue infection? Utility?

Back 86

- Often of limited use, but is offered in conjunction w/ ongoing reinforcement of hygiene measures
- Nasal decolonization w/ Mupirocin bid x 5-10 days
- Topical body decolonization w/ Chlorhexidine or dilute bleach baths (1/4 cup bleach / 1/4 tub)
- Oral antimicrobial therapy recommended only for treatment of active infection and not for decolonization

Front 87

How do you decolonize the nares?

Back 87

- Mupirocin bid x 5-10 days

- Oral antimicrobial therapy recommended only for treatment of active infection and not for decolonization

Front 88

How do you decolonize the body/skin?

Back 88

- Topical body decolonization w/ Chlorhexidine or dilute bleach baths (1/4 cup bleach / 1/4 tub)

- Oral antimicrobial therapy recommended only for treatment of active infection and not for decolonization

Front 89

Case: 27 yo male grad stuent presents to health services. Feels fatigued, complains of fever, swollen glands, and mild sore throat for 2 weeks. Ill-appearing w/ temp 99.9. Throat injected, no tonsillar exudates. Bilateral anterior and posterior cervical adenopathy. Mild hepatosplenomegaly. Faint, erythematous macular rash over torso.

He is given penicillin for possible "strep throat". He returns in a week still feeling bad.

Strep screen negative. Monospot negative. WBC low but normal. Low hemoglobin.

What is the most likely diagnosis?

Back 89

Acute Retroviral Syndrome (primary HIV infection)

Front 90

What is the common presentation of Acute Retroviral Syndrome?

Back 90

- Headache
- Fever
- Rash
- Adenopathy
- Weight loss
- Cytopenias, especially thrombocytopenia