| Competitive exclusion | May outcompete pathogenic bacteria by consuming nutritional resources, producing antibacterial molecules, or modulating the pH of the gastrointestinal macroenvironment. [26] |
| Effects on intestinal SCFAs | May maintain SCFA (acetate, propionate, and butyrate) concentrations during antibiotic use, reducing diarrhea by promoting sodium and water absorption. [21] |
| Effects on bile acid concentrations | Some probiotic strains may attenuate antibiotic-induced increases in colonic primary bile acids that may increase susceptibility to Clostridioides difficile infection. [21] [36] |
| Effects on barrier function | May prevent antibiotic-induced disruption in the intestinal barrier. [21] [37] |
| Immune effects | May reduce antibiotic activation of inflammatory pathways. [21] [26] Lactobacillus and Saccharomyces-based probiotics may upregulate the innate and adaptive immune systems. [28] |