How quickly does E.coli gain resistance against antibiotics?

[Eagle9]

As well-known, the bacteria (particularly E.coli) can gain the resistance against antibiotics. In Wikipedia its mechanism is written:

It may take the form of a spontaneous or induced genetic mutation, or the acquisition of resistance genes from other bacterial species by horizontal gene transfer via conjugation, transduction, or transformation. Many antibiotic resistance genes reside on transmissible plasmids, facilitating their transfer.

I would like to know:
1) Are there any OTHER mechanisms for gaining the resistance? Can the bacteria gain resistance when it has got antibiotic, LB broth in medium and nothing more? In other words, we have got only one species of bacteria (E.coli in this case), the antibiotic and LB broth, but there are no other species of bacteria that can give/lend plasmids to E.coli. So, can E.coli gain resistance in this situation?
2) How quickly do the bacteria generally gain the resistance? Can it happen during several hours or more time is needed?

 

[Ygggdrasil]

1. As stated in the wikipedia article, spontaneous or induced genetic mutation offer a pathway to resistance that does not involve horizontal gene transfer. Such mutations may prevent the antibiotic from binding its target or increase efflux of the antibiotic from the bacterium.

2. For this and the above question, you may find the following article useful:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3534735/

 

[Eagle9]

Ygggdrasil

1. As stated in the wikipedia article, spontaneous or induced genetic mutation offer a pathway to resistance that does not involve horizontal gene transfer. Such mutations may prevent the antibiotic from binding its target or increase efflux of the antibiotic from the bacterium.

And such mutation comes from plasmids?

For this and the above question, you may find the following article useful:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3534735/

So long! By the way I am earning my master's degree now and I have got very similar thesis. In some experiments we observed the gained resistance (but this happened during 1 day) for E.coli and I wanted to know where does it comes from

 

[Ygggdrasil]

YgggdrasilAnd such mutation comes from plasmids?

No, such mutation can occur in the genomic DNA. Check the Nature Genetics paper for examples (e.g. for trimethoprim resistance, mutations emerge in the DHFR gene on the bacterial chromosome).