An Increase in Prominent Probiotics Represents the Major Change in the Gut Microbiota in Morbidly Obese Female Patients upon Bariatric Surgery

The global increase in obesity carries inherent health implications, with an increased BMI being a known risk factor for diseases such as type 2 diabetes, cardiovascular diseases, or different cancer types. The long-term effectiveness of diet therapy in addressing morbid obesity is extremely limited, with no adequate pharmaceutical agents available as treatment options, resulting in bariatric surgery being the only viable option to achieve and maintain significant long-term weight loss. Something that plays an important role in overall human health is the gut microbiome and its complex composition, which is usually altered and reduced in complexity/diversity in severely obese patients. In this study, the influence of bariatric surgery and the resulting weight loss on the gut microbiome composition of twelve morbidly obese (BMI ≥ 40) adult female central European patients was investigated by comparing the relative abundances of the major microbial phyla Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria pre- and post-surgery. We also aimed to give insight into the major changes in individual prominent and promising future probiotic bacteria characterized by an overall increase in abundance accompanied by a switch of enterotypes. Identifying specific microbial alterations associated with successful weight-loss outcomes may contribute to the development of future therapeutic interventions by supplementation with next-generation probiotics.