some back keeria have evolved so they can now fight off the most powerful of drugs. >> reporter: theld health organization says it is happening right now. antibiotic resistance is growing all over the world. common diseases, which have for decades been treatable with antibiotics, are developing ever-stronger resistance. the main bacteria are all becoming more difficult to treat. the wide-spread prescription of antibiotics started in the 1940s, and revolutionized medicine. but in recent years we have all taken too many antibiotics too often, and that has allowed bacteria to develop resistance. what the world needs now are new drugs to deal with this emerging crisis. but no new antibiotics are being produced. >> we have had resistance over many, many decades. for more intensefy to select the pressure on an organism, such as anti-b antibiot antibiotics, the more quickly it will develop a resistance. so we have to get away from that, we have to sensibly manage what we have and develop new products. >> reporter: antibiotics should only be given when absolutely necessary. more should be do