Use Mac Conkey agar plates where u can get only GNB.
well..try to subculture on appropriate agar plate and obtain an isolated colony of the Gram -ve bacteria (after confirmation through staining). Pick that colony and inoculate in broth medium to get the pure culture..but do it aseptically to avoid any contamination.
use selective agar for Gram -ve bacteria...n then isolate the single colony followed by enrichment in d broth..b4 that do perform some Gram -ve confirmation testing..
It depends on what bacteria you need to isolate. There are so many G- and +. McConkey will not get so many G-ves.
It depends on the genus you are dealing with. MacConkey works well for the Enterobacteriaceae, Vibrios, Aeromonas, Pseudomonas and some other Gram-negative bacteria that grow on it. Usually Gram-positive bacteria are vancomycin-susceptible and Gram-negatives are vancomycin-resistant. For highly fastidious and antibiotic susceptible Gram-negatives i.e. members of the Pasteurellaceae, Francisella, Brucella, you can either use antibiotics that they are resistant to or consider increasing the agar concentration of the medium. If the Gram-negative is mixed in a broth - try to get it out by dilution plating onto agar.
Than x to all.I got the culture by dilution plating on media with different ph and nacl conc.
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