Diluting rifampicin for culture use - (May/10/2010 )

Hi everyone

I made 1mg/ml rifampicin in an attempt to use it in culture. However there has not been any growth. I diluted my powder in methanol. Could that be the reason my cells arent growing? Should I use water instead?


Thanks

I always use DMSO for rifampicin, but methanol should work too I think.
Water is not ok.



I use a stock solution of 100mg per 10ml

so 1mg/ml seems not too much.

are you sure your bacteria are rifampicin resistent?
And when did you inoculate? a few hours ago or?

pito on May 10 2010, 01:44 PM said:

Thanks pito

Well actually I was just making up rifanpicin for my supervisor in an experiment he is going to use in his practical course with some undergrads. The rifampicin was made up a while ago for the course last term, but it had not worked since (meaning that no cells grew in culture). My boss said my rifampicin could be one of the many reasons it didnt work. I was just told of this today where he needs the same stuff for the same course now.

I am just going to try and run my own test. Grow my cells overnight, then make a lawn of overnight cells on two plates. One with spots of different dilutions of my antibiotics in MeOH, and another with just one spot with pure methanol, and see if my plate with pure methanol grew.

He says he puts 80uL of the ampicillin into 20ml of culture, so even if methanol has an bacteriocidal/static action the dilution would have made that effect negligeable.