Participants were recruited for bariatric surgery: BMI > 40 kg/m2 or BMI > 35 kg/m2 with T2D/hypertension
Gut microbial diversity increased within the first 3 months after RYGB and remained high 1 year later. RYGB led to altered relative abundances of 31 species: Escherichia coli, Klebsiella pneumoniae, Veillonella spp., Streptococcus spp., Alistipes spp., and Akkermansia muciniphila.
Fecal samples
Quantification of gut microbiomes at baseline (), 3 months () after RYGB, and 12 months () after RYGB
Weight-stable women 9 years after randomization to either RYGB or LSG and matched for weight and fat mass loss Control: 2 groups of nonoperated women with BMI matched to patients’ (1) presurgical BMI and (2) postsurgical BMI
Significant differences in microbiota composition for RYGB versus OBS samples but not for LSG versus OBS or RYGB versus LSG. 29 microbial genera differed significantly between RYGB and controls: ↑ Gammaproteobacteria class and ↓ three species in the Firmicutes phylum (C. difficile, C. hiranonis, and G. sanguinis). At the genus level: ↑ Proteobacteria (Escherichia, Klebsiella, and Pseudomonas) in RYGB. No different microbiota profiles for RYGB and LSG patients.
10 unrelated subjects with obesity grade III at 3 time points: (1) baseline (2) 3 months after LSG (3) 6 months after LSG () or dietary weight loss regimen ()
Both interventions resulted in changes of the B/F ratio but with an inverse relationship between the main phyla. LSG: ↑ Bacteroidetes and ↓Firmicutes Dietary intervention: ↓ Bacteroidetes and ↑Firmicutes In LSG: Bacteroidetes correlated negatively with weight. Firmicutes positively correlated with weight.
3 men and 3 women, recruited for RYGB 38–53 years Preoperative BMI 40.9–52.1
↓ Firmicutes, Bacteroidetes, Actinobacteria, and Cyanobacteria. However, the ratios of B/F shifted from 0.99 to 1.31, showing an apparent increase. ↑ Proteobacteria, Verrucomicrobia, and Fusobacteria. 3 months after RYGB, ↑ E. cancerogenus, Veillonella parvula, V. dispar, Shigella boydii, and Salmonella entérica. Postoperative abundances of these species were also significantly higher than those in lean controls.
Fecal samples
16S rDNA
Illumina HiSeq 2000
Shotgun sequencing
BMI: body mass index, expressed as kg/m2; RYGB: Roux-en-Y gastric bypass; LSG: sleeve gastrectomy.
