Clinical Implications of Antimicrobial Resistance

Question 1

What defines a nosocomial infection

Answer 1

• Not incubating at the time of admission

- Develops 48 hours after admission

Question 2

What defines a multidrug-resistant pathogen?

Answer 2

• Resistance or intermediate susceptibility to > or = to 3 antimicrobials or antimicrobial groups

Question 3

What classifies a MDR Pseudomonas aeruginosa?

Answer 3

– Non‐susceptibility (e.g., resistant or intermediate) to at least one agent in at least 3 antimicrobial classes of the following 5 classes:

– Cephalosporins (cefepime, ceftazidime)
– β‐lactam/β‐lactamβ‐lactamase inhibitor combination (piperacillin, piperacillin/tazobactam)
– Carbapenems (imipenem, meropenem, doripenem)
– Fluoroquinolones (ciprofloxacin or levofloxacin)
– Aminoglycosides (gentamicin, tobramycin, or amikacin)

Question 4

Example of a central-line associated bloodstream infection

Answer 4

MRSA

Question 5

Example of a catheter associated UTI

Answer 5

ESBL E. Coli

Question 6

What can cause Ventilator-associated pneumonia?

Answer 6

• MDR Gram Negatives like Pseudomonas aeruginosa

- MRSA

Question 7

EBSL?

Answer 7

Extended spectrum beta lactamases
Stops:
 - Penicillin
 - Cephalosporins
 - Aztreonam (Monobactam)

Question 8

Who do we find ESBL in and what do we worry about?

Answer 8

Found in Gram negative organisms like Klebsiella, E.Coli, Enterobacter, Proteus, Pseudomonas

• Also associated with other antimicrobial resistances like fluoroquinolones, aminoglycosides, TMP-SMX

Question 9

How do we treat ESBL gram negatives?

Answer 9

Have to use Carbapenems like Imipenem and Ertapenem

Question 10

So what happens when we get Carbapenem-resistant Enterobacteriaceae?

Answer 10

Urgent CDC issue, we see it with persistent Kelbsiella.

We got to use weird ass antibiotics: Colistin (bad neuro and nephrotoxicity) and another agent like Tigecycline.

Question 11

What is the Hypervirulent strain of C. Diff?

Answer 11

NAP-1: Increased toxin production

Question 12

What puts you at risk for C.Diff?

Answer 12

• Hospitalization with antibiotic exposure
• Advanced age ( > 65 years = 10x increased risk)
• Proton pump inhibitors ( 3x increased risk)
• Surgery and chemotherapy

Question 13

C. iff colitis can present in two ways:

Answer 13

• Pseudomembranous colitis

- Fulminant colitis

Question 14

Discuss symptoms of pseudomembranous colitis

Answer 14

• Diarrhea + pseudomembranes seen on endoscopy

- Thickened colonic wall

Question 15

Discuss symptoms of fulminant colitis

Answer 15

• Fever
• Diarrhea (may have ileus)
• Severe abdominal pain and cramping
• Hypotension/lactic acidosis
• Marked leukocytosis-leukemoid (>40K WBC)
• Toxic Megacolon
• Bowel perforation

Question 16

How do we treat C. Diff?

Answer 16

• Stop antibiotic that is causing the issue
• Avoid anti-motility agents like loperamide
• Correct electrolytes and fluid loss
• GIVE antibiotic therapy: Fidaxomicin (new agent) or give fecal transplant
• Surgery if perforated or about to perforate

Spores are RESISTANT to alcohol, be VERY careful

Question 17

Risk factors for the gram negative rod Acinetobacter

Answer 17

• Prologed hospitalization
• ICU admission
• Recent surgery
• Recent antibiotics
• Central venous catheters
• Nursing home

Question 18

How do we treat MDR Aceinetobacter?

Answer 18

Toxic/unconventional treatments

• Colistin (again, nephro and neurotoxic)
• Aminoglycosides (nephro and ototoxicity)
• Sulbactam

Question 19

Risk factors for Methicillin Resistant Staph Aureus (MRSA)

Answer 19

• Hospitalization in previous 12 months
• Nursing home resident
• Close contact with MRSA patients
• Hemodialysis
• Indwelling intravenous catheters
• Prolonged antimicrobial therapy
• Surgical procedures

Question 20

How do we treat hospitalized patients with MRSA?

Answer 20

– Vancomycin‐ first line therapy
– Daptomycin (not for pneumonia)
– Linezolid
– Ceftaroline (SSTI)
– New agents: oritavancin, telavancin, dalbavancin

Question 21

How do we treat outpatient with MRSA?

Answer 21

– TMP‐SMX
– Clindamycin
– Doxycyline
– Linezolid
– Tedizolid

Question 22

What disease agents are classified as urgent threats by the CDC due to antibiotic resistance

Answer 22

1. C. diff

2. Carbapenem resistant Enterobacteriaceae

Question 23

What disease agents are classified as serious threats by the CDC due to antibiotic resistance

Answer 23

1. Multidrug resistance Actinobacter
2. Extended spectrum B-lactamase producing Enterobacteriaceae
3. Methicilin resistant Staph aureus