Why Do Some Infections No Longer Respond to Antibiotics?

You have a urinary tract infection (UTI), you take an antibiotic, and yet the symptoms persist. Or worse, they come back soon after. This is called antibiotic resistance. Simply put, it means that some bacteria have learned to outsmart the drugs meant to kill them. This phenomenon, which is a growing concern for the medical community, is increasingly affecting common infections like cystitis in women.

But how did we get here? And more importantly, how can we avoid making the problem worse?

What is antibiotic resistance?

When you take an antibiotic, it kills (or inhibits) the bacteria responsible for the infection. But if antibiotics are taken too often, for too long, or at the wrong dose, some bacteria can develop resistance. They create biological "shields" that make them immune to standard treatments.

A very common example: Escherichia coli the main bacteria behind most UTIs is becoming increasingly resistant to widely used antibiotics like fosfomycin (Monuril) or trimethoprim-sulfamethoxazole (Bactrim).

Why shouldn’t you take antibiotics without medical advice?

It can be tempting especially when you’ve had cystitis before to reuse the same antibiotic as last time, without seeing a doctor. But this is a dangerous habit.

Not every infection is caused by the same bacteria. By always using the same antibiotic, you promote the growth of resistant bacterial strains. The result? Next time, the drug may no longer work and the infection becomes harder to treat.

Self-medication should be avoided at all costs.

Should you get a urine test before taking an antibiotic?

Yes in most cases, especially if:

• Symptoms are not typical,
• It’s a recurring infection,
• A previous treatment failed.

This test is called a urine culture (ECBU). It helps identify the bacteria involved and test which antibiotics it is sensitive to.

Important: never do a urine test after starting an antibiotic, as it will distort the results. So always:

• Get the test done before taking any antibiotics.
• Begin treatment only after confirming the right antibiotic with your doctor.

Recurrent cystitis: why changing antibiotics regularly is essential

Some women experience recurrent UTIs (more than 3 per year). In these cases, an antibiotic may work well at first, until it eventually stops being effective.

Why? Because repeatedly using the same treatment gives the bacteria time to adapt and resist. They "recognize" the drug and develop survival strategies.

That’s why you should never ignore recurrence:

• Each episode should ideally be investigated with a urine culture.
• The doctor can adjust the treatment or consider preventive strategies (probiotics, hygiene measures, local treatments, etc.).

How to protect yourself from infections while avoiding resistance

Here are some simple but effective steps:

• Drink plenty of water to avoid urine stagnation.
• Urinate after sexual intercourse to flush out bacteria.
• Choose cotton underwear; avoid tight clothing.
• Never keep leftover antibiotics "just in case".
• See a doctor promptly at the first symptoms don’t self-medicate.

In conclusion

Antibiotic resistance is not inevitable, but it requires collective awareness physicians, medical laboratories, and patients all have a role to play. Every unnecessary or poorly targeted treatment increases the risk of more resistant bacteria emerging. In this effort to promote appropriate use, the Bionext laboratory plays an active role in limiting resistance by providing targeted antibiograms. These analyses help guide the selection of the most effective antibiotic, thereby reducing the frequency of inappropriate antibiotic therapies.

To protect our health today and in the future, we must learn to use antibiotics wisely, based on reliable and personalized data.