$7.$ Study the pulsed$-$field gel electrophoresis $($PFGE$)$ figure below discussed in lecture.

a$.$ Outline the basic steps in pulsed$-$field gel electrophoresis $($PFGE$).(6$ points$)$

b$.$ Is the St$.$ Louis Rams MRSA isolate more similar to USA$200$ or USA$100.$ Why $(4$ points$)?$

c$.$ Design an experiment to determine which strains have the mec cassette $($contains mecA$)$ that does not need methicillin. What positive and negative controls do you need?$(8$points$)$Similarity $(\%)$

Isolate

Reference

St$.$ Louis Rams professional football team, Missouri

Professional football team $A$

College football team, California

College professional football team, Pennsylvania

Fencers, Colorado

Prison inmates, Mississippi

Prison inmates, Georgia

Prison inmates, Texas

Children, Tennessee

Children, California

Men who have sex with men, California

Hospital Strain USA$100$

Hospital Strain USA$200$