Individuals who produce too much gastric acid in their stomach are often are prescribed proton pump inhibitors (PPIs), a group of drugs that prevent the production of acid for the treatment of ulcers, gastroesophogeal reflux disease (GERD), and other conditions related to acid production. Scientists at the Mayo Clinic in Arizona and Minnesota published a study last week in the journal Microbiome that found that the prolonged use of PPIs resulted in a reduction in gut microbiome diversity. The authors hypothesized that this reduced gut diversity is predisposing patients using PPIs to Clostridium difficile infection, an often-fatal bacterial infection that we have written about extensively on the blog.
Previous observational studies had shown a correlation between PPI usage and C. diff infection, however this study set out to identify what was actually causing this link. The scientists took fecal samples from 9 healthy subjects before, during, and after they were given either a high or low-dose PPI treatment. They also took fecal samples from 5 patients with untreated C. diff infections and compared the bacteria in the fecal samples between the healthy patients and untreated patients infected with C. diff.
After taking PPIs, the healthy individuals’ gut microbiomes started looking very similar to those of patients with untreated C. diff. The number of bacterial species was significantly reduced from before they were exposed to PPIs, and the reduction was independent of dosage. This reduction of bacterial diversity in the gut doesn’t mean that patients on these medications will definitely become infected with C. diff, but it does likely predispose patients to the infection and more easily allow the bacteria to colonize the gut.
The study found that after 28 days of PPI treatment the reduced gut diversity can be reversed, however it is not clear what prolonged PPI usage does to the gut microbiome. This study included only a small number of subjects and future studies will hopefully be expanded and include patients who are prescribed PPIs for treating a specific condition. Better understanding the impact that PPIs have on the gut microbiome may also allow for the development of probiotics that could help counteract the effects of PPIs and help keep the gut microbiome diversity stable.