Inhibition of Escherichia coli bacteria

Enterococcus bacteria (green) and Escherichia coli bacteria (brownish) on a chromogenic agar medium. The first section shows a heavy growth of Enterococci while E. coli bacteria have been inhibited due to antibiotic substances from the urine specimen that had been applied on the agar.
The plate has been processed with a certain streaking technique by an automated system in order to eventually get isolated bacteria colonies on the growth medium. A definite amount of urine has been applied on the plate and dragged across the agar's surface. That way the concentration of urine is decreasing, as well as of bacteria and any antibiotic substances in it. Bacteria levels will be highest in the first streaking section and reduce to lower levels in each of the subsequent sections. The final streaking section will have the least amount of growth and many isolated colonies.
Due to the fact that the concentration of antibiotics has been high in the first section, the E.coli bacteria have been inhibited but a distinct growth can bee seen in this photograph as soon as the concentration decreases.


Flickr page for this photo.

Visit the Eye for Science Flickr group.

Get the "Eye for Science" widget here and install it on your own blog. Spread the scienticity!

Like this image? Want it for your smartphone wallpaper?
Use this QR Code to load it on your smartphone and enjoy!