The overuse of antibiotics could lead to a time when it would be so ineffective that a normal infection could kill, according to the World Health Organization.

"Things as common as strep throat or a child's scratched knee could once again kill," WHO Director-General Dr. Margaret Chan said in a conference called "Combating Antimicrobial resistance: Time for Action" on Wednesday. Chan warned that microbes the cause the most common infections are starting to develop resistances to the drugs and that treating such infections in the future could be more difficult. Chan said that the world was entering a post-antibiotic era that could mean an end to modern medicine.

"Some sophisticated interventions, like hip replacements, organ transplants, cancer chemotherapy and care of pre-term infants, would become far more difficult or even too dangerous to undertake," she said. "Antimicrobial resistance is on the rise in Europe, and elsewhere in the world. Replacement treatments are more costly, more toxic, need much longer durations of treatment and may require treatment in intensive care units.

Speaking to a group of infectious diseases experts at Copenhagen, Chan said that the misuse of antibiotics had made microbes more resistant to treatment. Patients who have been infected with drug-resistant pathogens have an increased mortality rate of about 50 percent. Drug-resistant pathogen could also be found in food and there are more cases of drug-resistant pathogens surfacing in hospitals.

Antimicrobial resistance occurs when microorganisms render the medications used to cure the infections ineffective. The medication developed over the last few decades to treat diseases like tuberculosis, malaria, influenza, HIV and other bacterial infections will likely become ineffective in the future. Drug resistance could cause prolonged illness and higher death rates. It could also cause huge costs to developing countries.

Dr. Chan believes that there are a number of actions that can be done to avert this grim future. Doctors should prescribe antibiotics only when necessary. There needs to be a review in the use of antibiotics in food production and more stringent rules need to put in place to stop substandard and counterfeit medications.

"Much can be done. This includes prescribing antibiotics appropriately and only when needed, following treatment correctly, restricting the use of antibiotics in food production to therapeutic purposes and tackling the problem of substandard and counterfeit medicines."