Wastewater treatment plants (WWTPs) are designed to robustly treat polluted water. They are characterized by ceaseless flows of organic, chemical and microbial matter, followed by treatment steps ...before environmental release. WWTPs are hotspots of horizontal gene transfer between bacteria via conjugative plasmids, leading to dissemination of potentially hazardous genetic material such as antimicrobial resistance genes (AMRGs). While current focus is on the threat of AMRGs spreading and their environmental maintenance, conjugative plasmid transfer dynamics within and between bacterial communities still remains largely uncharted. Furthermore, current in vitro methods used to assess conjugation in complex microbiomes do not include in situ behaviours of recipient cells, resulting in partial understanding of transfers. We investigated the in vitro conjugation capacities of WWTP microbiomes from inlet sewage and outlet treated water using the broad‐host range IncP‐1 conjugative plasmid, pKJK5. A thorough molecular approach coupling metagenomes to 16S rRNA DNA/cDNA amplicon sequencing was established to characterize microbiomes using the ecological concept of functional response groups. A broad diversity of recipient bacterial phyla for the plasmid was observed, especially in WWTP outlets. We also identified permissive bacteria potentially able to cross WWTPs and engage in conjugation before and after water treatment. Bacterial activity and lifestyle seem to influence conjugation extent, as treated water copiotrophs were the most represented strategist amongst transconjugants. Correlation analysis highlighted possible plasmid transmission routes into communities between the sewage to the environment, with identification of keystone members (e.g., Arcobacter) potentially involved in cross‐border exchanges between distant Gram‐positive and Gram‐negative phyla.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The aim of the present study was to investigate the effect of Bifidobacterium animalis subsp. lactis, BB-12®, on two primary end points – defecation frequency and gastrointestinal (GI) well-being – ...in healthy adults with low defecation frequency and abdominal discomfort. A total of 1248 subjects were included in a randomised, double-blind, placebo-controlled trial. After a 2-week run-in period, subjects were randomised to 1 or 10 billion colony-forming units/d of the probiotic strain BB-12® or a matching placebo capsule once daily for 4 weeks. Subjects completed a diary on bowel habits, relief of abdominal discomfort and symptoms. GI well-being, defined as global relief of abdominal discomfort, did not show significant differences. The OR for having a defecation frequency above baseline for ≥50 % of the time was 1·31 (95 % CI 0·98, 1·75), P=0·071, for probiotic treatment overall. Tightening the criteria for being a responder to an increase of ≥1 d/week for ≥50 % of the time resulted in an OR of 1·55 (95 % CI 1·22, 1·96), P=0·0003, for treatment overall. A treatment effect on average defecation frequency was found (P=0·0065), with the frequency being significantly higher compared with placebo at all weeks for probiotic treatment overall (all P<0·05). Effects on defecation frequency were similar for the two doses tested, suggesting that a ceiling effect was reached with the one billion dose. Overall, 4 weeks’ supplementation with the probiotic strain BB-12® resulted in a clinically relevant benefit on defecation frequency. The results suggest that consumption of BB-12® improves the GI health of individuals whose symptoms are not sufficiently severe to consult a doctor (ISRCTN18128385).
The aim of the present study was to investigate the effect of Bifidobacterium animalis subsp. lactis, BB-12 super( registered ), on two primary end points - defecation frequency and gastrointestinal ...(GI) well-being - in healthy adults with low defecation frequency and abdominal discomfort. A total of 1248 subjects were included in a randomised, double-blind, placebo-controlled trial. After a 2-week run-in period, subjects were randomised to 1 or 10 billion colony-forming units/d of the probiotic strain BB-12 super( registered ) or a matching placebo capsule once daily for 4 weeks. Subjects completed a diary on bowel habits, relief of abdominal discomfort and symptoms. GI well-being, defined as global relief of abdominal discomfort, did not show significant differences. The OR for having a defecation frequency above baseline for greater than or equal to 50 % of the time was 1.31 (95 % CI 0.98, 1.75), P=0.071, for probiotic treatment overall. Tightening the criteria for being a responder to an increase of greater than or equal to 1 d/week for greater than or equal to 50 % of the time resulted in an OR of 1.55 (95 % CI 1.22, 1.96), P=0.0003, for treatment overall. A treatment effect on average defecation frequency was found (P=0.0065), with the frequency being significantly higher compared with placebo at all weeks for probiotic treatment overall (all P<0.05). Effects on defecation frequency were similar for the two doses tested, suggesting that a ceiling effect was reached with the one billion dose. Overall, 4 weeks' supplementation with the probiotic strain BB-12 super( registered ) resulted in a clinically relevant benefit on defecation frequency. The results suggest that consumption of BB-12 super( registered ) improves the GI health of individuals whose symptoms are not sufficiently severe to consult a doctor (ISRCTN18128385).
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