E. coli is a facultatively anaerobic gram-negative rod that
produces acid and gas from lactose and does not use citrate as its sole
carbon source. E. coli O157:H7 is identified by its somatic (O)
and flagellar (H) antigens; it is also sorbitol-negative.
The figure shows DNA fingerprints from E. coli O157:H7 isolates
submitted by four different laboratories to PulseNet. The DNA fingerprints
were made by Pulsed Field Gel Electrophoresis. The bacteria were isolated
from apple juice produced in one state and patients from three different
Which isolates are genetically the same? What can you conclude?
Do you need any additional information from the patients?
E. coli is a normal and necessary part of human intestinal
microbiota. Why is it necessary to identify E. coli O157:H7?
If these are all E. coli isolates, why do the DNA fingerprints