Subject: How are bacteria dependent on streptomycin?

Dear Sir,
I am wondering if you could possibly help me with the question I 
have been asked by a student of mine. I have been unable to find 
the clear explanation to it. The question is " Why are some bacteria 
dependent on an antibiotic streptomycin such as the so-called 
streptomycin-dependent mutant. ? how can this antibiotic is so vital 
for this mutant. It is easy to understand how bacteria can become 
resistant to streptomycin but not how they become dependent on 
their own enermy. Please spare sometime to help me get out of 
this puzzle.
	
Please reply at your earliest convenience.

Best regards,
Preecha Homchampa

Re: How are bacteria dependent on streptomycin?