Emerging Infections

Question 1

Define emerging pathogen. Provide specific examples.

Answer 1

• previously unknown organism that causes disease
• previously identified organism that recently acquired ability to cause disease
• previously identified organism that acquired capacity to resist antibiotic therapy

EXAMPLES

• ebola
• raccoon rabies
• malaria
• yellow fever
• E. coli
• penicillin resistant S. pneumoniae

Question 2

Describe how specific features of a P. aeruginosa infection in a CF lung can lead to rapid evolution of resistance.

Answer 2

hyperchanging DNA allows rapid evolution to find a variation that thrives in the CF environment

Question 3

Describe the impact of multidrug efflux pumps on antimicrobial treatment. Why do these pumps appear so often when antibiotic resistance evolves?

Answer 3

• resistant to one, resistant to all

- easily transmitted

Question 4

List ways in which a physician can reduce the danger of emerging pathogens.

Answer 4

• stay informed regarding new treatments
• develop policy
• educate patients about proper use

Question 5

Describe general approaches (old and new) to antibiotic drug discovery.

Answer 5

OLD

• reductionist approach: identify MOA and design targets against virulence factors (useful for vaccines)
• genomic approach: sequence genome and design drug against all potential virulence factors

NEW
- attack intrinsic resistance approach: identify mechanisms of resistance (biofilms, efflux pumps), ensure lead compound works, design drug to attack resistance mechanism

Question 6

List societal, ecological, and evolutionary factors driving ABX.

Answer 6

• human demographics, behavior, sexual practices, longer life spans
• technology and industry => misuse of antibiotics in livestock
• economic development and land use => movement of populations, disruptions of societies, poor sewage control
• international travel and commerce
• microbial adaptations and changes
• breakdown of public health measures => not as much of a priority as it should be

Question 7

Describe how misapplication of drugs facilitates evolution of ABX.

Answer 7

• inappropriate prescription (misdiagnosis)
• over-prescription
• shortened duration (incomplete course)
• reduce amount of drug

All of these factors allow selection => spontaneous evolution of resistance => bacterial growth of resistant colonies