Antibiotic resistance explained

Antibiotics are prescribed to treat some types of bacterial infection. Antibiotic resistance occurs when bacteria change in response to the use of these medicines.

In 2018, the World Health Organisation (WHO) released data on antibiotic resistance, revealing high levels of resistance to a number of serious bacterial infections in both high- and low-income countries.

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Fast facts

How do antibiotics work?

Antibiotics work by killing bacteria or preventing them from spreading further. They are sometimes prescribed by your doctor to treat or prevent some types of bacterial infection. However, antibiotics don’t always work and can’t be used to treat viral infections such as cold, flu and many chest infections and sore throats.

What is antibiotic resistance?

Antibiotic resistance is caused by a number of factors, including overuse and inappropriate prescribing. This means that antibiotics are becoming less effective and have led to the emergence of ‘superbugs’. These are strains of bacteria that have developed a resistance to standard types of antibiotics.

Why is antibiotic resistance important?

The World Health Organisation (WHO) states that antibiotic resistance is one of biggest threats to global health, food security and development today. While antibiotic resistance can occur naturally, global misuse of antibiotics is accelerating the process.

Antibiotic resistance makes bacteria more difficult to treat. This can lead to heightened medical costs, longer hospital stays and in some cases, increased mortality.

This chapter covers

  • Scope of the problem
  • Impact
  • What can I do to help prevent antibiotic resistance?

Scope of the problem

The World Health Organisation (WHO) reports that antibiotic resistance is rising to dangerously high levels in all parts of the world. New methods of resistance have been reported and are spreading globally. This has a serious impact worldwide, as it threatens our inability to treat common infectious diseases.

As a result, an increasing amount of infections – including pneumonia, tuberculosis, blood poisoning, gonorrhoea, and foodborne diseases – are all becoming more difficult, and sometimes impossible, to treat as antibiotics become less effective.


When first-line antibiotics stop working to fight infections, more expensive treatments must be used. This can result in a longer duration of illness and treatment, often in hospitals, increasing the costs of healthcare as well as the economic burden on families and societies.

Antibiotic resistance threatens the achievements of modern medicine. Organ transplants, chemotherapy, and surgeries such as caesarean sections become more dangerous without effective antibiotics to prevent and treat infections. Antibiotic resistance could lead to a post-antibiotic era, in which common infections and minor injuries can once again cause mortality.

What can I do to help prevent antibiotic resistance?

  • Only use antibiotics when prescribed by a doctor
  • Never demand antibiotics if your doctor says you don’t need them
  • Complete your full prescription, even if you start feeling better
  • Always follow your doctor’s advice when using antibiotics
  • Never share or use leftover antibiotics
  • Take measures to prevent infections by regularly washing your hands, avoiding close contact with sick people, preparing food hygienically, practising safer sex, and making sure your vaccinations are up to date

Always follow your doctor’s advice.

What causes antibiotic resistance?

To help prevent antibiotic resistance, it’s important to know how it occurs. Antibiotic resistance can be caused by a number of different factors.

Ventola (2015) names five potential causes: overuse, inappropriate prescribing, extensive agricultural use, availability of few new antibiotics, and regulatory barriers.

This chapter covers

  • Overuse
  • Inappropriate prescribing
  • Extensive agricultural use
  • Few new antibiotics
  • Regulatory barriers


Sir Alexander Flemming, who discovered the first antibiotic, raised the concern about their overuse as early as 1945. There is significant evidence to show a relationship between antibiotic consumption and the emergence of resistant bacteria strains. It is clear that the overuse of antibiotics is making antibiotics less effective. Despite warnings, antibiotics are still being overprescribed worldwide.

Inappropriate prescribing

A 2018 study funded by Public Health England found that as many as 1 in 5 antibiotics are inappropriately prescribed in the UK. These cases often involve antibiotics being prescribed for sore throats, coughs, sinusitis and ear infections. Inappropriate prescribing can sometimes occur when a doctor does not have access to diagnostic equipment, such as via video-only consultations.

Extensive agricultural use

WHO has urged farmers and the food industry to stop using antibiotics routinely to promote growth and prevent disease in healthy animals.

Few new antibiotics

There has been little progress in discovering new antibiotics since the 1980s. In order to prevent antibiotic resistance, we need to develop more medications.

Regulatory barriers

While medicinal regulation is important in protecting patients and ensuring safety in treatments prescribed, it can also stifle the development of new antibiotics.

Types of antibiotic-resistant bacteria

Public Health England (PHE) monitors the resistance rates in bacteria to help to optimise antimicrobial prescribing in healthcare.

PHE has published data on bacteria such as gonorrhoea, E. coli, K. pneumoniae, KO and MRSA. These bacteria, in particular, are becoming more resistant to antibiotics.

This chapter covers

  • Gonorrhoea
  • E. coli
  • K. pneumoniae
  • KO
  • MRSA


Gonorrhoea is the third-most prevalent sexually transmitted infection in the UK. It is commonly treated with antibiotics. However, the Neisseria gonorrhoeae bacterium that causes it, has become especially resistant to antibiotic treatment. The phrase ‘super gonorrhoea’ has been used by the media to describe a strain of gonorrhoea that has developed resistance to antibiotics.

E. coli

E. coli, also known as Escherichia coli, is a common form of bacteria usually found in the intestines. Most types of E. coli are harmless and exist naturally in the gut. However, some strains of E. coli can lead to serious food poisoning and infection. Public Health England reveals a 1.68% average increase in strains of E. coli resistant bacteria to six separate antibiotics.

K. pneumoniae

K. pneumoniae (Klebsiella pneumoniae) are bacteria usually found in the intestines and feces. K. pneumoniae infections are most commonly seen in those with weakened immune systems and can cause pneumonia and bronchitis. K. pneumoniae is resistant to at least six of the major antibiotics. Public Health England states that the prevalence of cases is increasing by 1.68%.


KO (Klebsiella oxytoca) is one of several Klebsiella bacteria found in the intestinal tract, mouth and nose. Inside your gut, they are considered healthy gut bacteria. However, outside of your gut, KO can cause serious infections. Singh, Cariappa and Kaur (2016) found that KO has a higher drug resistance than its contemporary, K. pneumoniae. Public Health England reports cases of KO increased by an average of 0.26% between 2013 and 2017.


MRSA (meticillin-resistant Staphylococcus aureus) is a type of bacteria that’s resistant to several major antibiotics. This means MRSA infections are usually harder to treat than other bacterial infections. As a result of this, MRSA has been coined as a ‘superbug’ in the media.

About the author

Medicspot provides trusted, accurate and up-to-date health information to the public. Our health information is authored and reviewed by our team of doctors.

Dr Zubair Ahmed

Dr Zubair Ahmed is a GP and the Co-founder and CEO of Medicspot. He has been a doctor for 12 years after obtaining his medical degree from the University of Aberdeen, Scotland. He worked across a wide array of specialities including cardiology, accident and emergency, and geriatrics before focusing his energies on becoming a General Practitioner.

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