Antibiotics research. Culture plates testing for antibiotic resistance of two strains (Staph1 & Staph2) of Staphylococcus aureus bacteria. The agar used depends on the nutrients needed to grow the bacteria. Disks of filter paper soaked in antibiotic are applied and the amount of bacterial growth is observed. The diameters of the clear areas can be measured to determine the level of resistance. The antibiotics being tested are, on the left plate clockwise from upper right: ciprofloxacin, mupirocin, vancomycin, clindamycin and rifampicin; and on the right plate: penicillin, erythromycin, fusidic acid, trimethoprim, chloralmphenicol and gentamicin.