MDRO Colonization Risk Increased With Gastric Acid Suppressant Use

Acid reflux, GERD. Gastroesophageal reflux disease. Stomach and digestive. Human anatomy. 3d illustrationAcid reflux, GERD. Gastroesophageal reflux disease. Stomach and digestive. Human anatomy. 3d illustration
The use of acid suppressants increases the odds of multidrug-resistant microorganisms (MDROs).

The use of acid suppressants increases the odds of multidrug-resistant microorganisms (MDROs), according to a review published in JAMA Internal Medicine.

An increasing concern and health threat is antibiotic resistance. Individuals who are MDRO carriers are at an increased risk of developing these infections, which are difficult to treat and could potentially contribute to the spread of these resistant bacteria. Antibiotic use, underlying illness, age, and international travel are all known risk factors for colonization with MDROs.

There has been evidence that the use of acid suppressant therapy may also be a possible risk factor for colonization with MDROs. A healthy intestinal microbiome and stomach acid naturally protect the gastrointestinal tract from exogenous bacterial colonization; however, acid suppressants have been shown to directly alter the composition of the microbiome composition and further, inhibition of gastric acid secretion leads to increased survival of bacteria that passes through the stomach into the intestinal tract. Evidence on whether acid suppressants increase the risk for MDRO colonization remains inconsistent and unclear. Because acid suppressants are now widely available and prescribed, with nearly 8% of the adults in the United States having used a proton pump inhibitor (PPI) and up to 70% of PPI use being inappropriate, it is important to understand the role acid suppressants in this field. Therefore, the authors of this review performed a systematical meta-analysis to examine the association of use of acid suppressants with the risk for colonization with MDROs.

In total, 26 observational studies with data from 29,382 patients were included in this review, of whom 38.9% used acid suppressing medications. Studies were selected on the basis of including a comparison of risk for MDRO colonization between patients who used gastric acid suppressants with those who did not; data was drawn from PubMed, Embase, the Web of Science Core Collection, and the Cochrane Central Register of Controlled Trials from database inception through July 8, 2019.

The primary outcome was the intestinal colonization with MDROs of the Enterobacterales order, which included extended -spectrum β-lactamases, carbapenemases, or plasmid-mediated AmpC β-lactamases; vancomycin-resistant enterococci; methicillin- or vancomycin-resistant Staphylococcus aureus; or multidrug-resistant Pseudomonas or Acinetobacter species.

Results demonstrated that acid suppression is associated with increased odds of MDRO colonization. Carriage of MDR Enterbacterales and of vancomycin-resistant enterococci was linked to acid suppression with an odds ratio (OR) of 1.60 (95% CI, 1.33-1.92; I2 = 54%) and an OR of 1.97 (95% CI, 1.49-2.60; I2 = 31%), respectively. This link was stronger for carbapenemase-producing MDR Enterbacterales that extended-spectrum β-lactamase–producing MDR Enterbacterales.

In terms of classes of acid suppressants, results of 17 studies on MDRO colonization in patients who only used PPI and 4 studies on such colonization in patients who only used histamine2 receptor antagonists showed that use of the former class of medication seemed to be associated with MDRO colonization, whereas the latter did not. However, the review authors noted that the lack of significant association between histamine2 receptor antagonists and MDRO colonization may be attributed to the small number of studies.

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Overall, the review authors concluded that, “In view of the global increase in antimicrobial resistance, stewardship to reduce unnecessary use of acid suppressants may help to prevent MDRO colonization.”


Willems RPJ, van Dijk K, Ket JCF. Vandenbroucke-Grauls CMJE. Evaluation of the association between gastric acid suppression and risk of intestinal colonization with multidrug-resistant microorganisms: a systemic review and meta-analysis. Jama Intern Med. 2020;180(4):561-571.