This is the no phage negative control. Add 20 ml. Centrifuge cultures at 5,000 rpm for 10 minutes. Resuspend each cell pellet in 2.5 ml. Calculate the frequency of Lac- mutants.
Antibiotics are antimicrobial agents, many of which are used to combat a bacterial infection.
Different genera, and indeed even different species and strains may differ in susceptibility to various antibiotics. Several methods are used for the determination the antibiotic susceptibility. The most common method is the standardized Kirby-Bauer agar diffusion technique. This technique has the advantage of predicting the clinical effectiveness of a given antibiotic with reasonable accuracy by noting the exact diameter of the zones of bacterial growth inhibition and comparing the data with a standard table of values. The table categorizes the organism in question as susceptible, intermediate or resistant.