Antibiotics have transformed modern medicine. They can turn potentially life-threatening bacterial infections into treatable conditions and make procedures such as surgery, cancer treatment and organ transplantation much safer.
But antibiotics have a serious limitation: bacteria can evolve ways to survive them.
This is known as antibiotic resistance.
Antibiotic resistance is becoming an increasingly important health concern worldwide. According to the World Health Organization (WHO), approximately 1 in 6 laboratory-confirmed bacterial infections globally was resistant to antibiotic treatment in 2023. WHO also reported that antibiotic resistance increased in more than 40% of the pathogen-antibiotic combinations it monitored between 2018 and 2023.
The problem is particularly important in countries and healthcare systems where infectious diseases are common and access to rapid diagnosis, appropriate treatment, infection control and surveillance may be limited.
Understanding antibiotic resistance can help patients use antibiotics more safely and recognise why doctors sometimes recommend testing before choosing an antibiotic.
What is antibiotic resistance?
Antibiotic resistance happens when bacteria develop the ability to survive an antibiotic that would normally kill them or stop their growth.
It is important to understand that the person does not become resistant to the antibiotic. The bacteria become resistant.
For example, suppose a person has a bacterial infection and the bacteria are normally sensitive to antibiotic A. Antibiotic A may kill most of the bacteria and help the person recover.
However, if some bacteria carry resistance mechanisms, they may survive. These bacteria can multiply and potentially spread to other people.
Over time, antibiotic-resistant bacteria can become more common.
Resistance can develop through genetic mutations or by bacteria acquiring resistance genes from other bacteria. Some resistance genes can move between bacteria through genetic material such as plasmids.
This is why antibiotic resistance is not simply a problem for one patient. Resistant bacteria can spread through communities, hospitals, healthcare facilities, animals, food and the environment.
What are the types of antimicrobial resistance?
Antimicrobial resistance can be understood in several ways.
One classification is based on the organism involved: antibacterial, antiviral, antifungal and antiparasitic resistance.
Resistance can also be described as intrinsic or acquired.
Intrinsic resistance means a microorganism naturally has characteristics that make a particular medicine ineffective.
Acquired resistance develops when an organism gains new resistance characteristics. This can happen because of mutations or the acquisition of resistance genes from other microorganisms.
Bacteria can use several mechanisms to survive antibiotics. They may change the target that the antibiotic attacks, produce enzymes that destroy or modify the drug, reduce the amount of antibiotic entering the cell, pump the antibiotic back out or develop alternative biological pathways that allow them to bypass the drug’s effects.
Which is the main cause of antibiotic resistance?
The misuse and overuse of antibiotics are among the most important drivers of antibiotic resistance.
Antibiotics create selective pressure. Sensitive bacteria may be killed, while bacteria carrying resistance mechanisms can survive and multiply.
Important examples include:
- Taking antibiotics when they are not needed.
- Using antibiotics for viral illnesses such as many common colds and influenza.
- Taking the wrong antibiotic for an infection.
- Using leftover antibiotics without medical advice.
- Sharing antibiotics with another person.
- Using antibiotics obtained without appropriate medical evaluation.
- Incorrect prescribing or unnecessary broad-spectrum antibiotic use.
- Excessive or inappropriate antibiotic use in animals and agriculture.
- Poor infection prevention and control.
- Inadequate sanitation and hygiene.
- Limited access to accurate diagnostic testing.
WHO identifies inappropriate antimicrobial use, poor water and sanitation, inadequate infection prevention and control, limited access to vaccines and diagnostics, and insufficient development of new medicines as important factors contributing to AMR.
What are the signs of antibiotic resistance?
There is no unique symptom that tells you an infection is antibiotic-resistant.
A person with a resistant bacterial infection may initially have the same symptoms as someone with a susceptible infection.
Depending on the infection, symptoms may include:
- Persistent fever
- Chills
- Cough or breathing difficulty
- Pain or burning while urinating
- Frequent urination
- Abdominal pain
- Diarrhea
- Wound redness, swelling or discharge
- Persistent skin infection
- Increasing pain or swelling
- Symptoms that do not improve as expected despite treatment
A particularly important warning sign is failure to improve despite appropriate antibiotic treatment. However, treatment failure does not automatically mean antibiotic resistance. The diagnosis may be incorrect, the infection may be viral, the antibiotic may not reach the infected tissue adequately, or another complication may be present.
Laboratory testing is often needed to determine whether bacteria are resistant.
How is antibiotic resistance tested?
Antibiotic resistance is commonly assessed using microbiology testing and antimicrobial susceptibility testing (AST).
Depending on the suspected infection, a healthcare professional may collect a sample such as:
- Urine
- Blood
- Sputum
- Wound or pus
- Throat or other swab
- Stool
- Other relevant clinical specimens
The laboratory may first identify whether bacteria are present and determine the organism responsible.
The bacterial isolate can then be tested against different antibiotics to determine which medicines are likely to work.
A report may classify an organism as susceptible, intermediate or resistant, depending on the testing method and applicable laboratory standards.
Molecular tests can also detect particular resistance genes or mechanisms in selected circumstances. WHO highlights the importance of reliable bacteriology, susceptibility testing and diagnostic capacity in the global AMR response.
For some infections, a culture and sensitivity test can therefore help doctors move from an empirical antibiotic choice to a more targeted treatment.
What is the most common antibiotic-resistant infection?
There is no single antibiotic-resistant infection that can accurately be called the most common worldwide because resistance varies by organism, infection, country, healthcare setting and antibiotic.
Urinary tract infections caused by resistant Escherichia coli are an important and common example.
Other major resistant bacterial infections include those involving:
- Klebsiella pneumoniae
- Staphylococcus aureus, including MRSA
- Acinetobacter species
- Pseudomonas aeruginosa
- Enterococcus species
- Drug-resistant Mycobacterium tuberculosis
- Drug-resistant Neisseria gonorrhoeae
WHO’s latest global surveillance report specifically highlights resistant E. coli and K. pneumoniae among major drug-resistant Gram-negative pathogens associated with bloodstream infections.
Why are doctors worried about antibiotic resistance?
Doctors are concerned because antibiotic resistance can make infections harder, more expensive and sometimes impossible to treat.
A resistant infection may require:
- A different antibiotic
- Multiple antibiotics
- Intravenous treatment
- Longer treatment
- Additional laboratory testing
- Longer hospitalisation
- Specialist care
- More intensive monitoring
The consequences extend beyond infectious diseases. Effective antibiotics are important for many modern medical procedures because surgery, chemotherapy, transplantation and other treatments can carry a significant infection risk.
WHO estimates that bacterial AMR was associated with more than 4.7 million deaths globally in 2021.
What are the dangers of antibiotic resistance?
The dangers range from treatment failure to serious complications and death.
Treatment failure
The antibiotic initially selected may not work, allowing the infection to continue.
Longer illness
Patients may remain unwell for longer and require additional treatment.
More hospitalisation
Serious resistant infections can require longer hospital stays and intensive care.
More expensive treatment
Second-line or specialised medicines can be more expensive and may require hospital-based administration.
More side effects
Some alternative antibiotics have significant adverse effects and require careful monitoring.
Spread to others
Resistant bacteria can spread from an infected or colonised person to others.
Greater risk during medical procedures
If effective antibiotics become less reliable, procedures involving a risk of infection become more difficult to perform safely.
WHO notes that AMR increases the risk of severe illness, disability and death while increasing healthcare costs and pressure on healthcare systems.
How do you fix antibiotic resistance?
There is no single medicine that “fixes” antibiotic resistance.
If a person has an antibiotic-resistant infection, the immediate goal is to identify the organism and select an antibiotic that is effective against it, whenever an effective treatment is available.
Doctors may use culture and susceptibility testing to guide treatment.
At a population level, controlling antibiotic resistance requires several measures:
- Use antibiotics only when medically appropriate.
- Choose the correct antibiotic for the infection.
- Improve diagnostic testing.
- Strengthen infection prevention and control.
- Improve vaccination coverage.
- Maintain good hand hygiene.
- Improve sanitation and access to clean water.
- Use antibiotics responsibly in veterinary medicine and agriculture.
- Strengthen surveillance of resistant organisms.
- Invest in new antibiotics and other treatment approaches.
The WHO’s updated Global Action Plan on AMR for 2026–2036 adopts a One Health framework because the problem crosses human health, animal health, food systems and the environment.
Is antibiotic resistance permanent?
Not necessarily.
Resistance is a characteristic of bacteria, not a permanent change in the person’s body.
At an individual level, the bacteria causing an infection may remain resistant, disappear after successful treatment or be replaced by bacteria with different characteristics.
At a population level, resistance can sometimes decline when the selective pressure created by particular antibiotics decreases. However, resistance genes can persist and spread, and some bacteria can retain resistance even when antibiotic exposure changes.
Therefore, antibiotic resistance should not be considered something that will simply disappear on its own.
Can we reverse antibiotic resistance?
Resistance can sometimes be reduced or reversed at a population level, but there is no guaranteed way to reverse it in every bacterium or every patient.
Evidence from infection-control and antibiotic-stewardship programmes shows that reducing unnecessary antibiotic exposure and preventing transmission can reduce the prevalence of certain resistant organisms.
Vaccination can also help because preventing infections reduces the need for antibiotics in the first place.
The most realistic goal is therefore to slow the emergence of resistance, prevent its spread and preserve the effectiveness of existing antibiotics while developing new treatments.
What kills antibiotic-resistant bacteria?
There is no single substance or antibiotic that kills all antibiotic-resistant bacteria.
A bacterium resistant to one antibiotic may still be susceptible to another. Some bacteria, however, can become resistant to several antibiotic classes, creating multidrug-resistant infections.
The treatment depends on:
- The bacterial species
- The site of infection
- The resistance mechanism
- The patient’s age and health
- Previous antibiotic exposure
- Laboratory susceptibility results
- Local resistance patterns
For this reason, doctors should not simply keep changing antibiotics without understanding what organism is causing the infection.
In severe infections, infectious-disease specialists and microbiologists may be involved in selecting appropriate treatment.
Which country has the worst antibiotic resistance?
There is no scientifically reliable single answer to which country has the “worst” antibiotic resistance worldwide.
Countries differ in how they collect samples, which infections they monitor, which antibiotics they test and how comprehensive their surveillance systems are. Comparing countries using one resistance percentage can therefore be misleading.
WHO’s latest global data indicate that resistance is particularly high in the South-East Asia and Eastern Mediterranean regions, where approximately one in three reported infections were resistant in 2023.
India is an important part of this discussion. WHO has reported high levels of antimicrobial resistance among bacteria commonly responsible for infections in India, including E. coli, Klebsiella pneumoniae and Acinetobacter baumannii.
That does not mean every infection in India is resistant, nor does it mean India can accurately be labelled the single “worst” country.
The more useful question is: Which bacteria, in which infection, and against which antibiotic?
How can antibiotic resistance be prevented?
Everyone has a role to play.
Patients
Do not take antibiotics simply because you have a cold, flu or another illness that does not require them.
Take antibiotics only when prescribed or recommended by an appropriate healthcare professional. Do not share medicines or use someone else’s prescription.
If you have been prescribed an antibiotic, follow the instructions carefully and speak to your doctor if you experience side effects or are unsure how to take it.
Doctors and healthcare professionals
Healthcare professionals can help by prescribing antibiotics only when appropriate, selecting the most suitable drug and dose, reviewing treatment when laboratory results become available and following antimicrobial stewardship principles.
Healthcare facilities
Hospitals and diagnostic laboratories play an important role in infection prevention, surveillance, accurate microbiology testing and responsible antibiotic use.
Communities
Hand hygiene, vaccination, safe food practices and good sanitation can reduce infections and therefore reduce the need for antibiotics.
Why antibiotic testing matters
One of the most important lessons from the antibiotic-resistance crisis is that the right diagnosis matters.
Not every fever requires an antibiotic. Not every cough is a bacterial infection. Not every urinary symptom is caused by the same organism.
When bacterial infection is suspected, appropriate diagnostic testing can sometimes identify the organism and determine which antibiotics are likely to be effective.
This approach helps doctors avoid unnecessary treatment and can make treatment more targeted when antibiotics are genuinely required.
WHO has identified stronger diagnostic capacity as an important part of the global response to AMR.
Frequently asked questions about antibiotic resistance
What is antibiotic resistance in simple words?
Antibiotic resistance means that bacteria have developed the ability to survive an antibiotic that previously could kill them or stop them from growing.
Does antibiotic resistance mean my body is resistant to antibiotics?
No. The bacteria are resistant, not your body.
What is the main cause of antibiotic resistance?
The inappropriate use and overuse of antibiotics are major causes. Poor infection control, inadequate sanitation, antibiotic use in animals and limited development of new medicines also contribute.
Can antibiotic resistance be treated?
Yes, resistant infections can often be treated with another antibiotic to which the bacteria remain susceptible. However, some infections are extremely difficult to treat, which is why laboratory testing and appropriate antibiotic selection are important.
What are the signs of antibiotic resistance?
There is no specific symptom. An infection that does not improve as expected despite appropriate treatment may raise suspicion, but laboratory testing is usually needed to confirm resistance.
Is antibiotic resistance permanent?
Not necessarily. Resistance belongs to the bacteria and can change over time. However, resistant bacteria and resistance genes can persist and spread.
Can antibiotic resistance be reversed?
Resistance can sometimes decrease at a population level when antibiotic pressure and transmission are reduced. However, there is no universal way to reverse resistance in every bacterial strain.
What kills antibiotic-resistant bacteria?
The answer depends on the organism and its resistance pattern. A resistant bacterium may still respond to certain antibiotics, which can be identified through antimicrobial susceptibility testing.
What is antimicrobial resistance?
Antimicrobial resistance is the broader term for resistance involving bacteria, viruses, fungi and parasites. Antibiotic resistance specifically refers to bacteria resisting antibiotics.
What is the most common antibiotic-resistant infection?
There is no single worldwide answer. Resistant E. coli causing urinary tract infections is an important and common example, while MRSA, resistant Klebsiella, Acinetobacter, Pseudomonas and drug-resistant tuberculosis are other major concerns.
Why are doctors worried about antibiotic resistance?
Because resistant infections can lead to treatment failure, longer illness, longer hospital stays, higher costs, complications and death. Resistance can also make routine medical procedures riskier.
How is antibiotic resistance tested?
A clinical specimen may be cultured to identify the bacteria. The organism can then undergo antimicrobial susceptibility testing to determine which antibiotics are likely to work.
What are the dangers of antibiotic resistance?
The major dangers include treatment failure, prolonged illness, hospitalisation, increased healthcare costs, limited treatment options, spread of resistant bacteria and increased risk of severe disease and death.
The bottom line
Antibiotics remain one of modern medicine’s most important tools. The goal is not to fear antibiotics or avoid them when they are genuinely needed.
The goal is to use them correctly.
Antibiotic resistance develops when bacteria evolve or acquire mechanisms that allow them to survive antibiotic treatment. Unnecessary antibiotic use accelerates this process, while poor infection control allows resistant bacteria to spread.
Responsible prescribing, accurate diagnosis, appropriate laboratory testing, vaccination, hygiene, infection prevention and research into new treatments all form part of the solution.
For patients, one of the simplest messages is also one of the most important:
Do not take antibiotics just because you think you need them. Take them when a qualified healthcare professional determines that they are appropriate, and use them exactly as advised.
Protecting antibiotics today helps preserve effective treatment for tomorrow.
#BhaloTheko
Disclaimer:
No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.
Sources
- World Health Organization (WHO) – Antimicrobial resistance fact sheet, updated July 2026. WHO: Antimicrobial resistance
- World Health Organization – Global antibiotic resistance surveillance report 2025. WHO: Global antibiotic resistance surveillance report 2025
- World Health Organization – Global antibiotic resistance surveillance report 2025: summary. WHO: Surveillance report summary
- World Health Organization India – Antimicrobial resistance. WHO India: Antimicrobial resistance
- World Health Organization India – New Indian Priority Pathogen List. WHO India: Indian Priority Pathogen List
- Centers for Disease Control and Prevention (CDC) – About antimicrobial resistance. CDC: About antimicrobial resistance
- MedlinePlus – Antibiotic resistance. MedlinePlus: Antibiotic resistance
- Cleveland Clinic – Antibiotic resistance: what is it, complications and treatment. Cleveland Clinic: Antibiotic resistance
- Ventola CL. The antibiotic resistance crisis: part 1: causes and threats. Pharmacy and Therapeutics. 2015. PubMed Central: The antibiotic resistance crisis
- World Health Organization – Antimicrobial Resistance Diagnostic Initiative. WHO: Antimicrobial Resistance Diagnostic Initiative
[…] is treatable with antibiotics. However, the rise of antibiotic-resistant strains of Neisseria gonorrhoeae has made treatment more challenging in recent years. The CDC currently […]
[…] increases the risk of antibiotic resistance, which threatens public […]
[…] is treatable with antibiotics. However, the rise of antibiotic-resistant strains of Neisseria gonorrhoeae has made treatment more challenging in recent years. The CDC currently […]
[…] the common cold or flu, and using them for non-bacterial infections contributes to the problem of antibiotic resistance. They can be classified into two broad […]
[…] TB occurs when the bacteria do not respond to standard treatments. This can happen due to incomplete or improper use of antibiotics. Multi-drug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) are particularly […]