Microbiome impact from hyperbaric chambers

As I continue doing an in depth review of AI selected PubMed articles, I came across a study showing that hyperbaric chambers may actually make antibiotics less efficient and encourage antibiotic resistance. This is of concern because using hyperbaric chambers is popular in some communities based on logic such as: “increased oxygen level will kill off bad bacteria”

The sensitivity of selected bacteria to a range of antibiotics was tested under hyperbaric conditions used in saturation diving. The effect of hyperbaric helium and oxygen (heliox) on antibiotic stability and on induction of beta-lactamase was also determined. Increased resistance to penicillin (up to 23%) was shown by Staphylococcus aureus and to gentamicin (up to 46%) and rifampicin (up to 18%) by Escherichia coli and Salmonella typhimurium at 36 and 71 bar pressure. Exposure to 71 bar heliox did not affect antibiotic activity but increased the production of beta-lactamase in inducible S. aureus and Bacillus subtilis and production of beta-galactosidase in inducible E. coli. Increased resistance to antibiotics in saturation diving conditions can be attributed in some cases to the influence of hyperbaric pressure on induction mechanisms in bacteria. The experimental system devised for this work is suitable for more detailed examination of the influence of hyperbaric stress on antibiotic resistance and of its effect on induction mechanisms in general.

The effect of antibiotics on bacteria under hyperbaric conditions. [1996]

“The gram-negative bacilli generally gave reduced zone diameters in oxyhelium,” [1984]  – reduced zone means less effective.


In reviewing some studies, we find that it produces symptom relief especially where hypoxia is a factor (CFS/ME, FM, IBD, etc). The ‘Dave Berg’ school of thought ascribes this hypoxia to hypercoagulation in the tissue, often localized.

Bottom Line

Here we encounter a treatment that appears to have good short term effects (i.e. reducing hypoxia) with the possibility of encouraging the underlying condition by promoting resistance or altering the microbiome in an unfavorable direction.   A 1985 study raises questions about the impact of pressure on the cut microbiome which do appear to have been partially answered by a study this year:

We aimed to determine whether the composition of the fecal microbiota changes under hyperbaric conditions. In this study, we collected fecal samples from 6 healthy divers at three points during deep diving training (before, 2.1 MPa, end). The frequency of Clostridium cluster XVIII tended to be increased after compression. The frequencies of Clostridium cluster IV and subcluster XIVa were inversely correlated with that of Bacteroides. The compositional changes in the fecal microbiota exhibited interindividual variability. These findings suggest that hyperbaricconditions affect the fecal microbiota.

Effects of hyperbaric conditions on fecal microbiota. [2019]

Is it good or is it bad? It may depend on an individual circumstance.