Spot Plating Assay for the Determination of Survival and Plating Efficiency of Escherichia coli in sub-MIC Levels of Antibiotics

Spot plating is an alternative method to spread plating that generates more replicates in shorter periods of time. The spot plate assay is a method to determine the bacterial sensitivity to a sub-minimum inhibitory concentration of antibiotic by comparing the amount of cells plated to surviving cells that form colonies. This method is based on the principle that sensitive strains will form less colonies on a plate when challenged with antibiotics. Using this method, a greater amount of replicates can be performed in parallel to account for biological variation and obtain reliable and conclusive results.