Antibiotic Resistance

Question 1

What are some of the current, most urgent antibiotic resistant microorganism threats according to the CDC? (3)

Answer 1

• Clostridium Difficile
• Carbepenem-resistant Enterobacteriaceae (CRE)
• Drug Resistant Neisseria gonorrhoeae

Question 2

What is the most significant risk factor for development of CDI/CDAD?

Answer 2

Prior antibiotic exposure

• Any antibiotic can increase the risk of CDAD, although the following have been shown to have a significant risk for its development:
  
  • Fluoroquinolones
  • Macrolides
  • Clindamycin
  • Beta-lactam/beta-lactamase inhibitors
  • All 3 generations of cephalosporins

Question 3

What is currently our last line of antimicrobial defense against drug-resistant N. gonorrhoeae?

Answer 3

cephalosporins (cefixime and ceftriaxone)

Question 4

MRSA refers to S. aureus that is resistant to …

Answer 4

All currently available beta-lactam antibicrobial agents

Question 5

What drug groups has S. pneumoniae developed resistance to?

Answer 5

Beta-lactams and macrolides

Question 6

What antibiotic family is the last resort for treating ESBL-producing Enterobacteriaceae?

Answer 6

carbapenem

Question 7

What is a process whereby genetic material contained in small packets of DNA (sequences for antibiotic resistance) can be transferred between individual bacteria of the same species or even between different species?

Answer 7

Extrachromosomal Resistance (Horizontal Gene Transfer)

Question 8

What are the 3 possible mechanisms of horizontal gene transfer in bacteria?

Answer 8

• Conjugation
• Transduction
• Transformation

Question 9

Through what process can an antibiotic-resistant bacterium transfer the antibiotic resistance genes from an R-plasmid (circular strand of DNA) to a non-resistant bacterium?

Answer 9

Conjugation

Question 10

Through what process is free floating DNA in the environment that was released due to the death and lysis of another bacterium, taken up by roaming bacteria?

Answer 10

Transformation

Question 11

What is the process that occurs when bacteria-specific viruses (bacteriophages) transfer DNA between two closely related bacteria?

Answer 11

Transduction

Question 12

What are the 5 known mechanisms of action that antibiotics use to affect bacterial viability?

Answer 12

1. Inhibition of cell wall synthesis
2. Alteration in cell membrane permeability
3. Inhibition of ribosomal protein synthesis
   
   • Shared by MOST antibiotics
4. Suppression of nucleic acid (DNA) synthesis
5. Inhibition of folic acid synthesis

Question 13

What are the 7 known mechanisms of bacterial resistance to antibiotics?

Answer 13

1. Enzymatic antibiotic inactivation or destruction
   
   • Most common
2. Modification/protection of antibiotic target sites
3. Limiting antibiotic access to the bacterial cell
   
   • Most antibiotics
4. Active efflux of the antibiotic from the bacteria
5. Failure to, or decreased activation of, the antibiotic
6. Development of alternate bacterial growth requirements
7. Overproduction of bacterial antibiotic target sites

Question 14

What is currently the only remaining effective single antibiotic treatment for gonorrhea?

Answer 14

Cephalosporins

Cefixime or Ceftriaxone

Question 15

What is the duration of antibiotic resistance?

Answer 15

Effect is greatest in the month immediately after tx, but may persist for up to 12 months

Question 16

What is the MOA of beta lactams, and glycopeptides (vancomycin)?

Answer 16

Inhibition of cell synthesis (#1)

Question 17

What is the MOA of Macrolides, Licosamides, and Tetracyclines?

Answer 17

Inhibition of ribosomal protein synthesis (#3)

Question 18

What is the MOA of Metronidazole and Fluoroquinolones?

Answer 18

Suppression of DNA Synthesis (#4)