Then there are more serious consequences. According to the most recent statistics from the UK Health Security Agency, the total number of antibiotic-resistant infections has increased by 13% during a five-year period, averaging nearly 400 newly reported cases each week. Estimated deaths in people with a resistant infection such as E. coli rose by more than 300 to 2379 between 2024 and 2025.
These are UK statistics, but the antimicrobial problem is worldwide, and what happens in other countries affects us here.
When and why do we take antibiotics?
Our best defence against any infection is our own immune system. But occasionally, we will develop an infection that it can’t cope with quickly enough. Where that infection is caused by bacteria, antibiotics can save the day.
Almost any bacterial infection has the potential to make a person very ill – it depends on the person and the infection. Even trivial infections can become serious if the microbes gain access to vital organs, such as the meninges (membranes that cover and encase the brain and spinal cord) in cases of bacterial meningitis, or enter the bloodstream, potentially triggering a life-threatening, body-wide inflammatory reaction known as sepsis.
It’s also important to choose the right antibiotic – or even not use one at all. For example, pneumonia is one of the most common reasons patients end up in intensive care worldwide. In some cases, using the correct antibiotic is the difference between life and death.
Doctors are now finding that, in some situations, antibiotic treatment can make patients sicker because the drugs wipe out their microbiome – the “good” bacteria that live on and in us – slowing recovery.
What is antibiotic resistance and what causes it?
Antibiotic resistance is like repeating a surprise party – eventually, it loses its shock value. The first time an antibiotic attacks, it wipes out the majority of the microbes behind an infection. But with widespread and repeated use, the proportion of bacteria that are resistant increases until eventually the majority of bacteria are resistant, making the medicine useless.
So, a patient might be prescribed flucloxacillin for a bacterial skin infection such as impetigo, which is caused by the bacterium Staphylococcus aureus. But some strains are already resistant to the medication. These strains are known as meticillin-resistant Staphylococcus aureus (MRSA), which can cause serious wound and joint infections, chest infections, and enter the bloodstream to cause infections of the heart valves or sepsis.
Fifty years ago, infections with this bug were a rare dose of bad luck. By the turn of the millennium, there were thousands of hospital cases each year in the UK, and one person in every 50 carried the bug in their nose.
The main cause of antibiotic resistance is what we call “poor antibacterial stewardship”. In many parts of the world, especially in Central America and some African countries, you can buy antibiotics without seeing a doctor, leading to substantial overuse. The microbes then start to adapt to defeat those drugs, and as people move around the world, these resistant bacteria travel too.
Tuberculosis (TB) is a worrying case in point. Across sub-Saharan Africa, TB infection is extremely common. It usually takes at least six months of antibiotics to properly treat active TB. But people take whatever drugs they can afford for a couple of weeks, start to feel better and stop. The TB bacteria progressively become resistant to the drugs, so the patient may develop drug-resistant TB, which is much harder to treat.
All this has a knock-on effect, as the TB infection that the first patient spreads is now resistant. It’s as if a person has found ricin in the street, picked it up and run with it, spreading it everywhere.
We aren’t developing new antibiotics fast enough
The antibiotic drug pipeline is almost empty. Big Pharma needs to make money, and antibiotics are rubbish for their business model. It takes 10 years to make a new drug, costs £10bn, and they only make it through trials about 10% of the time. There is far more money to be made developing drugs for chronic conditions such as diabetes.
Added to this, doctors are reticent about using new antibiotics. Not only are they expensive, but doctors also want to avoid encouraging microbial resistance. So the new antibiotic becomes a treatment of last resort, the patent expires and other companies can clone the drug, leaving the pharmaceutical company that created it out of pocket.
Is there any hope for the future?
Antimicrobial resistance is a serious problem. We may be on a slippery slope to the point where a patient cannot have routine surgery because the risk of infection is very high. In a nightmare scenario, we could even return to the bad old days when hospitals killed more patients than they cured.
The good news is that we have never been better at drug design. Artificial intelligence (AI) will be transformative, helping scientists work out the structures of bacteria and target them more precisely. This process will be much faster than the current trial and error of today’s pharmaceutical development.
As told to Miranda Levy
Dr Chris Smith, a consultant in clinical microbiology and clinical virology at Addenbrooke’s Hospital in Cambridge and founder of The Naked Scientists podcast, about why antibiotic resistance is a growing threat, what it means for patients and whether new treatments could offer hope.
