Oxygen Treatment Makes Antibiotics Work Again – University of Copenhagen

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30 November 2017

Oxygen Treatment Makes Antibiotics Work Again

Antibiotics

Moving antibiotics treatment into a pressure chamber containing more oxygen than usual can make antibiotics work on bacteria that otherwise would be unaffected by the treatment, a new study conducted at the University of Copenhagen shows. The researchers believe this new knowledge can help patients with chronic infections.

             
Robust bacteria, which normally resist antibiotics treatment, can once again become sensitive to antibiotics when more oxygen in added under pressure. The bacteria are far more sensitive to most types of antibiotics when they are given oxygen, which they use to divide and grow. But the body’s own immune system can remove all oxygen from the bacteria, making them resistant to antibiotics.

But if you add more oxygen, antibiotics treatment will once again have an effect, a new study conducted at the University of Copenhagen and published in the scientific journal Antimicrobial Agents and Chemotherapy shows.

‘Antibiotics have a significantly greater impact on
the bacteria when you add oxygen. Patients with conditions such as cystic fibrosis suffer from some very serious infections that we normally cannot fight. This study may in the future make it possible to treat patients in a pressure chamber containing more oxygen’, says Associate Professor Peter Østrup Jensen from the Department of Immunology and Microbiology.


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The Bacteria Run Out of Steam
In patients with chronic infections the body’s own immune system attacks the bacteria by sending white corpuscles, the so-called phagocytes, to ’eat’ the bacteria cells. But highly robust bacteria are able to resist the attack by huddling together in slime in a so-called biofilm. Once the bacteria reach the biofilm stage it is virtually impossible for the body to kill the infection. Therefore, the patient must be treated with antibiotics.

But sometimes the bacteria are also able to fight targeted antibiotics treatment. And the body’s own immune system is actually partly to blame for that, a new study conducted at the Faculty of Health and Medical Sciences shows.

‘The phagocytes use up all the oxygen around the biofilm, making the bacteria unable to breathe. They thus lower their metabolism, which prevents them from dividing and growing. But the problem is that antibiotics do not work on bacteria with low metabolism. It is the first time we have been able to prove that it is the body’s own response to the infection that causes it to be impossible to fight with medicine’, says Postdoc Mette Kolpen from Rigshospitalet.

Pressure of 2.8 Atmospheres
In isolated pressure chamber tests the researchers have simulated chronic infections in cell cultures and the body’s response to the infections. In that connection they have added more oxygen than normally to see how it affects the cell cultures.

They used a pressure of 2.8 atmospheres, which is the same as Rigshospitalet uses in other forms of pressure chamber treatment. After 90 minutes, which is the time patients usually spend in pressure chambers, the researchers could see a significant effect. The antibiotics worked 99 per cent better in cell cultures subjected to pressure treatment than in cell culture outside the pressure chamber.

According to the researchers, the study suggests that they should expand and do clinical tests on patients in the pressure chambers at Rigshospitalet.

Read the entire study: ‘Hyperbaric oxygen sensitizes anoxic Pseudomonas aeruginosa biofilm to ciprofloxacin’

About the Study

The researchers have studied the robust bacteria Pseudomonas aeruginosa found in patients suffering from cystic fibrosis and in diabetes patients with chronic wounds.

The researchers used the known antibiotic ciprofloxacin.

The antibiotic treatment in the pressure chamber was 99 per cent more effective than outside the chamber.

Adding oxygen raises the bacteria’s metabolism causing them to divide and grow faster. Therefore, the researchers stress that timing is important when you use antibiotic treatment together with added oxygen under pressure.