Centers for Disease Control says 23,000 people a year die as a direct result of resistance and 14,000 die from related infections
The US faces "potentially catastrophic consequences" if it does not act immediately to combat drug resistance which already kills an estimated 23,000 people a year, the Centers for Disease Control and Prevention warned on Monday.
It is the first time the federal agency has estimated the death toll from bacterial infections that are difficult to treat because of antibiotic resistance.
Every year, at least two million people in the US become ill with drug-resistant infections, the CDC said. While the CDC estimates that 23,000 patients a year die as a direct result of drug resistance, it notes that a further 14,000 die every year from clostridium difficile, an infection related to antibiotic use.
A number of medical organisations, including the World Health Organisation (WHO), have warned that the overuse of antibiotics and the resulting evolution of resistant bacteria has caused a public health crisis.
In its report, released on Monday, the CDC lists 18 bacteria that pose "urgent", "serious" and "concerning" threats to patients and says that if no action is taken, some infections could become untreatable. It estimates that 50% of antibiotics prescribed are not needed or are not prescribed properly.
The CDC director, Tom Frieden, said: "If we're not careful, the medicine chest will be empty when we go there to look for a life-saving antibiotic. Without urgent action now, more patients will be thrust back to a time before we had effective drugs."
Frieden described antimicrobial resistance as "one of our most serious health threats" and said the loss of effective antibiotics would undermine life-saving treatments such as chemotherapy, kidney dialysis and organ transplantation. Even when alternative treatments are available, he said, patients with resistant infections are "often much more likely to die, and survivors have significantly longer hospital stays, delayed recuperation, and long-term disability".
The CDC report noted that antibiotic resistance costs $20 billion in excess healthcare costs each year in the US, with costs to society for lost productivity reaching as much as an additional $35 billion.
One of the most problematic bacteria is the staph infection MRSA, or methicillin-resistant staphylococcus aureus, which kills about 11,000 people every year.
Dr Margaret Chan, the director general of the WHO, said in March last year that the overuse of antibiotics was becoming so common she feared a situation where normal infections such as "strep throat or a child's scratched knee" could kill, because bacteria had evolved to survive treatments.
The CDC report said that while it was difficult to directly compare the amount of drugs used in food animals with the amount used in humans, there was evidence that more drugs were used in livestock. The use of antibiotics for promoting growth should be phased out, it said. The Natural Resources Defence Council (NRDC) estimates that 80% of antibiotics sold in the US are used on animals, and that 80% of those are used on healthy animals, in order to prevent disease and infection and to promote growth.
Mae Wu, a health attorney with the NRDC, said she welcomed the CDC report, which touched on the many aspects of the problem.
Wu said: "The misuse of antibiotics in humans is part of the problem, and in response many doctors and hospitals have developed antibiotic stewardship programs across the country to address it. But to fully overcome this threat, we need to put a stop to all inappropriate antibiotic uses causing resistance, meaning we cannot ignore the rampant misuse of antibiotics in livestock."
[Image: Scanning electron micrograph of Clostridium difficile bacteria from a stool sample via Wikipedia Commons]