Effects of anti-Helicobacter pylori concomitant therapy and probiotic supplementation on the throat and gut microbiota in humans

- The first study on the effect of concomitant therapy to the microbiota composition.
- Marked quantitative and qualitative alterations in the microbiota after treatment.
- Most of the changes in the gut microbiota reverted by Day 71, but not in throat.
- Higher antibiotic resistance rates of the microbiota were detected after treatment.
- Co-administration of probiotic may be more effective than post-antibiotic.

The microbiota within humans maintains homeostasis and plays important roles in human health. However, some situations such as the use of antibiotics may disrupt the microbiota balance and result in a series of adverse effects. This study aimed to investigate the effects of a commonly used anti-Helicobacter pylori concomitant therapy on the composition of the gut and throat microbiota and any antibiotic resistance that may develop. In addition to the standard regimen, two different supplementary probiotic regimens that both used Saccharomyces boulardii were included. Microbiological culture-based techniques were used to analyse the microbiota composition and antibiotic resistance. Our results showed marked quantitative and qualitative alterations in both the gut and throat microbiota after treatment with not only the standard concomitant therapy but also with either supplementary probiotic regimen. Nevertheless, most of the changes in the gut microbiota (except for yeast and Bacteroides spp. counts) reverted by Day 71, whereas the alterations in the throat microbiota appeared to persist. Patients treated with the eradication therapy in the absence of probiotic supplementation experienced the most pronounced disturbances in the throat microbiota, whereas changes in the throat microbiota appeared to stabilize in the groups that received probiotic supplementation. We also detected higher antibiotic resistance rates for Enterobacteriaceae, Enterococcus spp. and Bacteroides spp. after treatment with the eradication therapy. Co-administration of probiotics is likely to be more effective than post-antibiotic supplementation, and although some beneficial effects were observed, the probiotic combination did not exert significant effects on the unbalanced commensal gut and throat microbiota composition.