The identity of Staphylococcus aureus isolated on Baird-Parker Agar must be confirmed with a coagulase reaction Though the medium is recommended for detection of coagulase positive Staphylococcus aureus , other bacteria may grow. Cultures of: Staphylococcus aureus Staphylococcus epidermidis Escherichia coli Enterobacter aerogenes Salmonella enteritidis 2. The golden appearance of colonies of some Divide each plate of MSA and MacConkey’s agar into two sections. For each dilution to be plated, aseptically transfer 1 ml sample suspension to 3 plates of Baird-Parker agar, distributing 1 ml of inoculum equitably to 3 plates (e.g., 0.4 ml, 0.3 ml, and 0.3 ml). Mannitol broth was then inoculated with the Gram-positive bacteria and a negative result was achieved. 2. Since only gram negative bacteria grew on the nutrient agar plate, an unknown was isolated and streaked on to a MSA plate which was a selective medium for gram positive bacteria. ManConkey agar is a selective and differential agar medium that contains bile salts, lactose and the dye crystal violet that is known to inhibit the growth of Gram positive bacteria. The S aureus colony was isolated from the plate culture and identified on the basis of the colonial and cellular morphology, Gram’s stain, and biochemical reactions.11,12 The isolated colony was heavily inoculated on a nutrient agar slant (Oxoid CM 3) to obtain a subculture and then incubated for 18 to 24 hours at 37ºC. Your name and lab section number. After incubation, the nutrient agar plate was examined to determine if isolated growth had been obtained (1). Examine several isolated colonies with a magnifying lens or with a dissecting microscope if you need. Nutrient agar is used as a test because it is used as a plate for isolation and purification. C. Nutrient agar (NA) plate cultures - Colonies on the NA plates should be studied with respect to their color and opacity (see NA slants above), and for their configuration, elevation, and margin (see Figure 3 on the following sheets). This indicated that the unknown was Staphylococcus aureus or Enterococcus faecalis. I think there would be no growth on the EMB agar plate since Staphylococcus aureus is a Gram positive bacteria and the EMB agar is a selective medium. Nutrient agar konsentrasi 3% lebih optimal sebagai media pertumbuhan bakteri Staphylococcus aureus. Petri dishes of Mannitol Salt agar, EMB agar, MacConkey’s agar and nutrient agar Procedure: (work in pairs) 1. Label the bottom of each plate with the name of the medium. For the best answers, search on this site ... Relying on the results from this MSA plate and a positive Nitrate result led to an initial deduction of Staphylococcus aureus. S. aureus - individual colonies on agar are round, convex, and 1-4 mm in diameter with a sharp border. Staphylococcus aureus - Gram positive, mannitol fermenting Staphylococcus epidermidis - Gram positive, does not ferment 1 Nutrient agar plate 1 Blood plate 1 MacConkey’s agar plate Control examples PROCEDURE 1. A gram stain was performed and determined to be gram positive cocci. Kesimpulan Jumlah koloni bakteri Staphylococcus aureus pada media Nutrient agar 2% dengan rata-rata jumlah koloni/plate adalah 131; Jumlah koloni bakteri Staphylococcus aureus pada media Nutrient agar 2,5% dengan On blood agar plates, colonies of Staphylococcus aureus are frequently surrounded by zones of clear beta-hemolysis. Staphylococcus aureus is not a fastidious organism and grows well in many different types of media.