Determining the Minimum Inhibitory Concentration of Enrofloxacin Against Avian Pathogenic E. coli

Begin with a suspension of avian pathogenic E. coli or APEC in growth media.

APEC is a Gram-negative bacterium that infects poultry by entering through the respiratory tract.

After breaching the mucosal layer, APEC adhere to epithelial cells, multiply locally, and disrupt the epithelial barrier to enter the bloodstream. The bacteria then spread to multiple organs, causing systemic infection.

Add an equal volume of the bacterial suspension to each well of a multi-well plate containing increasing concentrations of the antibiotic enrofloxacin.

Seal the plate and incubate under optimal bacterial growth conditions.

During incubation, enrofloxacin enters the bacterial cells and binds to DNA gyrase, inhibiting its interaction with DNA.

This interference halts DNA replication and results in bacterial cell death.

After incubation, visually examine each well for turbidity, which indicates bacterial growth.

The lowest concentration of enrofloxacin that shows no visible turbidity is identified as the antibiotic’s minimum inhibitory concentration.