The choice of purification methods and the source of the drug will determine the nature and amount of contaminants in the final medicine. (Nothing is ever 100% pure.) Moreover, protein folding, various kinds of enzymatic modifications and impurities inevitably introduce variation, sometimes with unexpected results.

FORBES: Commentary

As the viruses change color once they've reached impervious bacterial strains, in this case variants on Staphylococcus, they can reveal superbugs within 10 to 12 minutes -- a potentially lifesaving interval when current purification-driven methods can take hours.

ENGADGET