Effect of HN001 and BB536 on the healthy gut microbiota composition at phyla and species level: A preliminary study.

Aim: To evaluate the ability of HN001 and BB536 to colonize the intestinal environment of healthy subjects and modify the gut microbiota composition.

Methods: Twenty healthy Italian volunteers, eight males and twelve females, participated in the study. Ten subjects took a sachet containing 4 × 10 colony-forming units (CFU) of BB536 and 10 CFU of HN001, 30 min before breakfast (pre-prandial administration), while ten subjects took a sachet of probiotic product 30 min after breakfast (post-prandial administration). The ability of HN001 and BB536 to colonize human gut microbiota was assessed by means of quantitative real-time PCR, while changes in gut microbiota composition were detected by using Ion Torrent Personal Genome Machine.

Results: Immediately after 1-mo of probiotic administration, BB536 and HN001 load was increased in the majority of subjects in both pre-prandial and post-prandial groups. This increase was found also 1 mo after the end of probiotic oral intake in both groups, if compared to samples collected before probiotic consumption. At phyla level a significant decrease in abundance was detected immediately after 1-mo of BB536 and HN001 oral intake. This reduction persisted up to 1 mo after the end of probiotic oral intake together with a significant decrease of abundance if compared to samples collected before probiotic administration. Whereas, at species level, a higher abundance of , and was observed, together with a reduction of , , and abundance. In addition, during follow-up period we observed a further reduction in and , together with a decrease in and abundance. Conversely, the abundance of was increased if compared to samples collected at the beginning of the experimental time course.

Conclusion: BB536 and HN001 showed the ability to modulate the gut microbiota composition, leading to a significant reduction of potentially harmful bacteria and an increase of beneficial ones. Further studies are needed to better understand the specific mechanisms involved in gut microbiota modulation.