Question

Do you actually have to wait for incubation for Gram staining? Would it be useful to see something that would help you know what to expect to see on a plate?

*microbiology* *original question for reference**

You received a mixed broth culture and were instructed to identify all organisms present in that mixture. What are the first steps you should do to accomplish your goal?

Answer 1

Answer:
There is no need to wait for inoculation and incubation before Gram staining.

Gram staining can be performed on the clinical or any other sample or even the mixed broth culture that you need to identify all the organisms in.

Gram staining generates a primary report. It tell us what to expect in the growth media, starting with what growth media to use in order to isolate and identify the given mixed culture. For example, presence of gram negative rods will suggest that MacConkey's Agar or EMB agar will be useful for initial isolation and primary identification. Similarly, presence of Gram positive cocci in bunches tell you to use \blood Agar Plate to see the growth characters and hemolysis pattern of the organism. some time the presence of typical shapes like Vibrio (comma shaped - must look for growth in alkaline peptone water), Corynebacterium (club shaped, use special media), bacillus with drum stick appearance (probably Clostridium) will make it necessary to choose a medium that supports anaerobic growth, so on and so forth,

Gram stain is the first thing we do do when we want to isolate and identify an unknown organism.