When an organism develops resistance it usually makes an evolutionary trade-off. This ironically might make them susceptible to older style antibiotics who have

When an organism develops resistance it usually makes an evolutionary trade-off. This ironically might make them susceptible to older style antibiotics who have been phased out. However retesting these antibiotics are not really being done extensively due to there being little financial benefit. http://jac.oxfordjournals.org/content/70/8/2177.full http://jac.oxfordjournals.org/content/70/8/2177.full My experience with kids is that here in Spain they are using older antibiotics now to preserve the newer ones for serious infections trying to limit evolutionary pressure on the bacteria.