The world may be teetering on the edge of a “post-antibiotic” era, according to scientists who have found bacteria in China that are resistant to every known treatment, including the drug of last resort, colistin.

Experts have been warning for years of an “antibiotic apocalypse” that would send medicine back to the dark ages, with common infections proving lethal and surgery and cancer therapies, which depend on antibiotics, under threat. Some experts are claiming that the post-antibiotic age is already upon us, with 50,000 deaths a year now reported in the United States and Europe from infections that the drugs have lost the power to treat.

Where are we now?

There has been a dramatic increase in multi-drug resistant bacteria in the last few years, with gonorrhoea and tuberculosis becoming increasingly resistant to common antibiotics and some superbugs in hospitals now untreatable.

Until now, gram-negative bacteria such as E. coli have remained susceptible to a class of antibiotics called polymyxins. Colistin is the mostly widely used of these “last resort” antibiotics, which are used to treat infections that are resistant to other drugs. But Chinese and British scientists have found a strain of E. coli that is resistant to colistin in pigs, raw pork meat and in a small number of people in China.

The mutation, known as the MCR-1 gene, is already widespread in southern China. A report in The Lancet Infectious Diseases found resistance in 15% of raw meat samples and 21% of animals tested between 2011 and 2014. Even more worrying, this gene has already started to appear in human infections with 16 patients found to have resistance. There is also evidence it can move between different types of bacteria and has already spread to Laos and Malaysia.

How did we get here?

The discovery of penicillin by Alexander Fleming in 1929 transformed modern medicine with the microbe’s ability to successfully treat infections that had previously killed patients. But during his Nobel Prize acceptance speech in 1945, Fleming warned of the dangers of drug resistance. Since then we have seen bacteria develop resistance to almost all of the antibiotics we have in current clinical use.

Inappropriate and casual consumption of antibiotics (they are still prescribed for viral infections and in some countries it is easy to buy them without a prescription) and their widespread use in farming is driving resistance and putting at risk our reliance on antibiotics to treat life-threatening infections. Antibiotic use in modern farming has also increased dramatically, which is making the situation worse.

A recent World Health Organisation (WHO) survey has revealed dangerous misconceptions and a general lack of public awareness about antibiotic resistance, which are fueling the crisis.

Misunderstandings uncovered by the survey include people believing they should stop taking an antibiotic prescription when they start to feel better. This increases resistance because bacteria that have not been killed by the initial doses can multiply and mutate. Overuse of antibiotics also drives resistance — nearly two-thirds of respondents thought antibiotics were effective treatments for colds and flu. (Antibiotics can be used to treat bacterial and fungal infections. Colds and the flu are viruses, which are immune to the drugs.)

What would a post-antibiotic world look like?

The impending loss of antibiotics threatens modern medicine as we know it and raises the spectre of untreatable infections spreading across the world. Around 700,000 people die each year from drug resistant infections, but that figure will rise to 10 million by 2050 if no action is taken.

Scientists are warning that the resistant gene identified in China should act as a wake up call for the world.

Professor Timothy Walsh, who collaborated on the study, from the University of Cardiff, told the BBC News website: “All the key players are now in place to make the post-antibiotic world a reality.

“If MRC-1 becomes global, which is a case of when not if, and the gene aligns itself with other antibiotic resistance genes, which is inevitable, then we will have very likely reached the start of the post-antibiotic era.

“At that point if a patient is seriously ill, say with E. coli, then there is virtually nothing you can do.”

What can we do about it?

Is the situation hopeless? According to the WHO, there are ways to fight the tide of antibiotic resistance. If all countries adopted good practices for the prescription and use of antibiotics we could see a decline in the numbers of deaths caused by antibiotic resistant infections.

We can also prevent infections from happening in the first place with better hygiene, access to clean water, infection control in health-care facilities, and vaccination to reduce the need for antibiotics. The WHO is also calling for new diagnostics, antibiotics and better tracking of drug resistance.

Speaking in 2014 after the release of the WHO’s global report on antibiotic resistance, Dr Keiji Fukuda, WHO’s Assistant Director-General for Health Security, described it as a “global trend”.

“To turn this around in all parts of the world is going to take us decades. And it’s not going to be a one-time action. We’re going to have to sustain it,” he said. “It’s basically a race against the pathogens that we deal with.”