They have designed new synthetic molecules which are better able to overcome the bacteria's defences. A classic example of this is the development of penicillinase-resistant penicillin. These design efforts are continuing, and are perhaps just as important as the discovery of new antibiotics. It should be mentioned that the need to improve existing antibiotics is most pressing in the case of very efficient product categories, selecting for those bacteria which find a defence to original therapies. The design can target very specific elements of that defence, or can neutralise defences.
Antibiotic formulation is also important.
Some antibiotics achieve cures in the digestive tract with minimal disturbance to the ecology of the gut. Others, however prudently they may be used, have a more profound effect, and sometimes select pathogens that create new problems such as Clostridium dificile. Combined treatment with other antibiotics that attack C dificile is then imperative. Researchers must strive to achieve dosages or formulations that cure or prevent disease or provide optimum activity whilst presenting the minimum of risk. Formulation, dosage, side effects, efficacy and treatment schemes are all elements that make it possible to gauge accurately the features, advantages, benefits, risks and hazards of antibiotic use.