Can someone identify this bacteria for me? (Pictures) - (Dec/17/2013 )
I think they're E.coli but im not sure. I gram stained them both and they're both gram-negative (i think). The first one was from a source with a bunch of contimates. The sceond sample was from one of the individual cultures from the original contiminated sample. I assumed the first sample had E.Coli, but from the second sample it doesn't look entirely like the first. Could it be because i inoculated the wrong colony or because i only let the second sample grow for a day? I'm really new to this so any information would be helpful, thank you!
You can't definitively identify bacteria just based on a Gram stain. There are a range of tests that need to be performed to do this. All you can say from the Gram stain is that the bacterium (assuming you are looking at the bacilli) is that they are bacilli. Your Gram stain isn't ideal, if you think they are G- then they should be pink. It is also possible to get G+ bacilli . It is also helpful if you can describe where the contaminates came from and what is likely to be contaminating them, but it isn't absolutely essential.
I would say from the "pure culture" that you have picked the small g+ cocco-bacilli which are very visible in the background of your picture.
bob1 on Wed Dec 18 20:19:36 2013 said:
You can't definitively identify bacteria just based on a Gram stain. There are a range of tests that need to be performed to do this. All you can say from the Gram stain is that the bacterium (assuming you are looking at the bacilli) is that they are bacilli. Your Gram stain isn't ideal, if you think they are G- then they should be pink. It is also possible to get G+ bacilli . It is also helpful if you can describe where the contaminates came from and what is likely to be contaminating them, but it isn't absolutely essential.
I would say from the "pure culture" that you have picked the small g+ cocco-bacilli which are very visible in the background of your picture.
Thanks for the reply! I see that i've got mixed up on the gram staining colors. I'm assuming E.Coli can be ruled out now because it's not G-? Also, what tests are required for identifying bacteria? Thank you!
Universal Bacterial Identification by PCR and DNA Sequencing of 16S rRNA Gene
http://link.springer.com/chapter/10.1007%2F978-90-481-9039-3_28
Might help if you revealed the naturedentity of the contaminated material.