Debate: PPI is not associated with SIBO?

Yoshiharu Uno, MD, PhD

I believe that IBS is related to SBO and that SIBO is related to PPI. The reason is based on the fact that I have examined many patients in the experience of gastrointestinal physicians and gastroenterol endoscopists more than 30 years. Japan is the country that uses the most PPI in the world. In other words, the Japanese are affected most by PPI. The reason why PPI is used the most in the world in Japan is not simply because there are many people infected with H. pylori. The biggest factor is that the Japanese medical system is a public health insurance. In other words, because the individual burden of medical expenses of Japan is small, patients are given a lot of medicine. Among them, unnecessary drugs are included. If the patient complains of abdominal pain, PPI is prescribed even if there is no abnormality in the endoscopic examination. PPI is also added to the prescription of common cold medicine. PPI is also added to the prescription of lower back pain relief. PPI is also added to the prescription of bi-aspirin. And, in many patients with chronically administered PPI, the pH of the stomach has risen to 7-8, and duodenitis is occuring. Since almost all physicians do not measure the pH of the stomach, PPI will continue to be used against duodenitis. The patient is prescribed medication for 10 years or more than 20 years and PPI is administered from gastrostomy even if the patient can not take medicine.

From such clinical experience, I am suspecting the relationship between PPI and SIBO.

Also, there are so many laxative addicts in Japan. In many laxative addicts, I know that the ileocecal valve is often open. This valve dysfunction easily moves colonic bacteria to the ileum. This may lead to SIBO by retrograde infection.

In other words, I think that many SIBO are the influence of drugs (PPI and laxatives).

From Greece in 2016, there was interesting report that SIBO and PPI are irrelevant.

BMC Gastroenterol. 2016 Jul 11;16(1):67. doi: 10.1186/s12876-016-0484-6.

Small intestinal bacterial overgrowth is associated with irritable bowel syndrome and is independent of proton pump inhibitor usage.

In that study, they diagnosed SIBO in culture of aspirate of duodenum. And then, analysed patients were divided into those without history of recent PPI intake (n = 713) and into those with history of recent PPI intake (n = 184). The absolute counts of bacteria in the duodenal aspirates did not differ between groups.

For these results of the research, I express my opinion.

1) The cause of SIBO is an antegrade infection and a retrograde infection. Among them, PPI can cause an antegrade infection. Therefore, in the group of SIBO, when there is little antegrade infection, the relationship with PPI is reduced within the group.

2) Originally, regardless of the use of PPI, an antegrade SIBO can occur when the pH of the stomach is high. For example, Methanobrevibacter smithii grows in the range of ph 6.5-8. That is, even if there is a history of using PPI, it is difficult for a person whose stomach pH is low to cause an antegrade infection. Even without a history using PPI, an anterograde infection is likely to occur in people with high pH in the stomach. From the above, it should be studied to compare with the pH of the stomach, not the history of PPI.

3) There is possibility that the impact of long-term administration of PPI cannot be considered only with the medication history of PPI alone. As in Japan, there are actually groups that are being chronically used. However, if administration of PPI by a strictly controlled situation of measuring pH, PPI may not be trigger SIBO. Also, the pH of the stomach may be influenced not only by PPI but also by its diet.