Some raise concerns about the early signs of bacterial resistance to the drug in some patients.

FORBES: Magazine Article

Then again, bacterial resistance is a prevalent problem, with many drugs becoming less and less effective by the year.

FORBES: FDA OKs Aventis Antibiotic

Another physician I spoke to at the conference was fairly confident that continuing to take antibiotics when you feel better does increase bacterial resistance.

FORBES: How Giving Children Foods They Are Allergic To Can Cure Them, And Other Provocative Approaches In Evolutionary Medicine

Yet growing bacterial resistance to existing drugs and novel microbial threats make the urgency which drove the original development of penicillin as vital as ever.

ECONOMIST: The cost of drugs

Bacterial resistance is a serious problem.

FORBES: A Better Antibiotic?

Overprescribing of antibiotics can lead to bacterial infection resistance.

BBC: Antibiotics 'ineffective for coughs'

Microbial genetics is enabling a more precise definition of bacterial, viral and parasitic threats - and how they develop resistance to treatments.

BBC: The man who gives away ?600m a year

Meeting the threat of both common and rare infections that continue to develop resistance over time is a race between drug development and bacterial evolution.

FORBES: The Antibiotic Bubble -- A Quest For Continued Antibiotic Effectiveness