Differences in colony size of bacteria on agar plates

[oBWhat]

why are there extreme differences in colony size of bacteria on agar plates if these were plated at the same time and are supposed to be of the same clone / strain?

thanks

[kmunson779]

Do you mean that you have two "identical" plates that each has colonies of consistent size, but the colony sizes are different on the two plates, or that you have one plate that has colonies of different sizes on it?

For the first situation, I'd look at differences in how they were incubated or the composition of the plates (did the antibiotic get mixed in properly?). In the second situation, I'd examine the possiblity of satellite colonies (if amp was used) or try to restreak down to single cells.

[aftabac]

Hi
the difference in colony size is not very often. in most of the cases when we streak the same clone they have almos the same size on agar plate.
Yes! they have different size at some occassions, for example when you streak on plate then at the initial point of strak there is more colonies and at the end less. so due to large number at initial point and due to same amount of nutrients their size remain small as compared to colonies that are at the end of streak. but when you spread the bacteria on agar plate, this is not usually the case because the cells are almost uniformly distributed on plate, but if at some points they are more concentrated as compared to other place then their size remain small as i mentioned above.
some good comments are also given by Kmunson

more comments........

[oBWhat]

Thank you both... I see this when I am streaking the same clone on agar plates.

This I guess may also be to the concentration of bacteria in the sample and uneven separation of the bacteria...