Validating Antibiotic Susceptibility Testing

To establish the accuracy of this method, it was first important to validate the performance of standard antibiotics against several ATCC strains to determine the MIC values and compare them with those published by The Clinical and Laboratory Standards Institute (M100-S22, Volume 32 No 3. January 2012). In this assay, two of the quality control ATCC strains, namely Gram-positive Staphylococcus aureus ATCC 29213 and Gram-negative Escherichia coli ATCC 25922, were screened against the antibiotics tetracycline (bacteriostatic in action) and gentamicin (bactericidal in action) and the MIC determined through recording of the colour change observed.