Outbreaks and Molecular epidemiology

Question 1

Molecular epidemiology

Answer 1

-focuses on the contribution of potential genetic and environmental risk factors

• identified at the molecular level, to the etiology, distribution, and prevention of disease within families and across populations

Question 2

What additional factors are needed for epidemiological data?

Answer 2

-etiology (a cluster of infections with same organism)
-temporal infections (cluster of infections occurring at same time)
*dont draw conclusions about bacterial relatedness from susceptibility profiles

Question 3

How can infection be spread?

Answer 3

-auto infection?
-spread from another animal?
-common 3rd source?

Question 4

Advantages of susceptibility data

Answer 4

-information you have and are comfortable with
-quick, cheap

Question 5

Disadvantages of susceptibility data

Answer 5

-resistance phenotype poorly predicts relatedness
**exception: two organisms with very unusual phenotypes

Question 6

Phenotypic prediction problems

Answer 6

-homogenizing effect of local antimicrobial use
-horizontal gene transfer
-regionally unrelated organisms often have similar susceptibility profiles

Question 7

Molecular epidemiological techniques

Answer 7

1. based on DNA sequence
   -specific genes
   -whole genomes
2. Based on DNA sequence indirectly
   -restriction digestion patterns
   -PCR
   -combination of techniques (single specific locus, multiple locus, random amplification, whole genome sequencing)

Question 8

What is the best method?

Answer 8

Methods differ in ability to resolve strains

-whole genome sequencing= low specificity, high sensitivity, high resolving power