WASHINGTON (WASHINGTON POST) - Drug-resistant germs sicken about three million people every year in the United States and kill about 35,000, representing a much larger public health threat than previously understood, according to a long-awaited report released on Wednesday (Nov 13) by the Centres for Disease Control and Prevention.

The new estimates show that, on average, someone in the US gets an antibiotic-resistant infection every 11 seconds, and every 15 minutes, someone dies.

Bacteria, fungi and other germs that have developed a resistance to antibiotics and other drugs pose one of the gravest public health challenges and a baffling problem for modern medicine.

Scientists, doctors and public health officials have warned of this threat for decades, and the new report reveals the top dangers and troubling trends. More pathogens are developing new ways of fending off drugs designed to kill them, and infections are spreading more widely outside hospitals. No new classes of antibiotics have been introduced in more than three decades.

The report highlighted some successes. Hospitals have improved their methods for tracking and slowing the spread of resistant germs, and deaths from superbug infections have decreased by nearly 30 per cent since 2013. Experts say everyone can help control many of these pathogens by practising basic prevention: good hand hygiene, vaccination, safe food handling and safe sex.

In addition to germs that have evolved drug resistance, the report included a dangerous infection that is linked to antibiotic use: Clostridioides difficile (C. diff.). It can cause deadly diarrhoea when antibiotics kill beneficial bacteria in the digestive system that normally keeps it under control. When the C. diff. illnesses and deaths are added, the annual US toll of all these pathogens is more than three million infections and 48,000 deaths.

The CDC had previously estimated about two million antibiotic resistant infections and 23,000 deaths in a 2013 report. The new report used previously unavailable data, including electronic health databases from more than 700 acute-care hospitals. By using the new methods retrospectively, the CDC calculated that the 2013 estimate missed about half of the cases and deaths.

"A lot of progress has been made, but the bottom line is that antibiotic resistance is worse than we previously thought," said Mr Michael Craig, the CDC's senior adviser on antibiotic resistance.

The new numbers, though still conservative, underscore the magnitude of the problem, establish a new national baseline of infections and deaths, and will help prioritise resources to address the most pressing threats, infectious diseases experts said. These germs spread through people, animals and the environment.

The report details the toll that 18 pathogens are taking on humans, ranking the threat of each as "urgent", "serious" or "concerning".

Five germs account for the most urgent threats. Three are long-recognised dangers: C. diff., drug-resistant gonorrhea, and carbapenem-resistant enterobacteriaceae (CRE), also known as "nightmare bacteria" because they pose a triple threat. They are resistant to all or nearly all antibiotics, they kill up to half of patients who get bloodstream infections from them, and the bacteria can transfer their antibiotic resistance to other related bacteria, potentially making the other bacteria untreatable.

Two new ones were added to the urgent category since the CDC's 2013 report: a deadly superbug yeast called Candida auris that has alarmed health officials around the world; and a family of bacteria, ESBL-producing Enterobacteriaceae, that has developed resistance to nearly all antibiotics.

The CDC also added a new category in addition to the ones used to classify the 18 pathogens: A watch list of three germs that officials are monitoring because they have the potential to spread resistance widely or are not well understood in the US. They are a life-threatening fungus, azole-resistant Aspergillus fumigatus; a sexually transmitted infection called drug-resistant Mycoplasma genitalium; and drug-resistant form of Bordetella pertussis, commonly known as whooping cough, which can be prevented with a vaccine.

The report cites two worrisome trends: the increasing numbers of resistant infections outside hospitals, including highly drug-resistant gonorrhea; and the increasing ability of drug-resistant microbes to share their dangerous resistance genes with other kinds of bacteria, making those other germs untreatable, as well.

Antibiotic resistance is particularly deadly for patients in hospitals and nursing homes, and those with weak immune systems. But these hard-to-treat infections now threaten people undergoing common modern surgeries and therapies, such as knee replacements, organ transplants and cancer treatments.

"We see people from everyday life, who are young and otherwise healthy, who get a MRSA (methicillin-resistant Staphylococcus aureus) infection on their skin," said Dr Helen Boucher, chief of infectious diseases at Tufts Medical Centre, who cares for many transplant patients who are vulnerable to these infections, which the CDC lists as a serious threat.

Bacteria are constantly evolving to fend off the drugs used to kill them. As they mutate, some develop the ability to fight off different antibiotics and survive to multiply and spread resistance. The more antibiotics are used, in healthcare and agriculture, the less effective they become.

Overuse of antibiotics is a likely reason for the dramatic rise in resistant infections, the report said. Nearly a third of antibiotics prescribed in doctors' offices, emergency rooms and hospital-based clinics in the US are not needed, according to a 2016 study. Most of them were prescribed for conditions that do not respond to antibiotics, such as colds, sore throats, flu and other viral illnesses.

"The fact that we're seeing some of the greatest increases among resistant infections that are acquired outside of the hospital - combined with data we already have showing that approximately one in three outpatient prescriptions are completely unnecessary - underscores the need for improved antibiotic use in doctor's offices and other non-hospital settings," said Mr David Hyun, who researches and develops strategies for the Antibiotic Resistance Project at the Pew Charitable Trusts.