Intestinal methane production is associated with decreased weight loss following bariatric surgery

Dysbiome and Its Role in Surgically Relevant Medical Disease

Several surgically relevant conditions are directly or indirectly influenced by the human microbiome. Different microbiomes may be found within, or along, specific organs and intra-organ variation is common. Such variations include those found along the course of the gastrointestinal tract as well as those on different regions of the skin. A variety of physiologic stressors and care interventions may derange the native microbiome. A deranged microbiome is termed a dysbiome and is characterized by decreased diversity and an increase in the proportion of potentially pathogenic organisms; the elaboration of virulence factors coupled with clinical consequences defines a pathobiome. Specific conditions such as Clostridium difficile colitis, inflammatory bowel disease, obesity, and diabetes mellitus are tightly linked to a dysbiome or pathobiome. Additionally, massive transfusion after injury appears to derange the gastrointestinal microbiome as well. This review explores what is known about these surgically relevant clinical conditions to chart how non-surgical interventions may support surgical undertakings or potentially reduce the need for operation.

Breath Tests Used in the Context of Bariatric Surgery

This review article focuses on the use of breath tests in the field of bariatrics and obesitology. The first part of the review is an introduction to breath test problematics with a focus on their use in bariatrics. The second part provides a brief history of breath testing. Part three describes how breath tests are used for monitoring certain processes in various organs and various substances in exhaled air and how the results are analyzed and evaluated. The last part covers studies that described the use of breath tests for monitoring patients that underwent bariatric treatments. Although the number of relevant studies is small, this review could promote the future use of breath testing in the context of bariatric treatments.

Modulatory effects of polysaccharides from plants, marine algae and edible mushrooms on gut microbiota and related health benefits: A review

Naturally occurring carbohydrate polymers containing non-starch polysaccharides (NPs) are a class of biomacromolecules isolated from plants, marine algae, and edible mushrooms, and their biological activities has shown potential uses in the prevention and treatment of human diseases. Importantly, NPs serve as prebiotics to provide health benefits to the host through stimulating the proliferation of beneficial gut microbiota (GM) and enhancing the production of short-chain fatty acids (SCFAs). The composition and diversity of GM play a critical role in regulating host health and have been extensively studied in recent years. In this review, the extraction, isolation, purification, and structural characterization of NPs derived from plants, marine algae, and edible mushrooms are outlined. Importantly, the degradation and metabolism of these NPs in the intestinal tract, the effects of NPs on the microbial community and SCFAs generation, and the beneficial effects of NPs on host health by modulating GM are systematically highlighted. Overall, we hope that this review can provide some theoretical references and a new perspective for applications of NPs as prebiotics in functional food and drug development.

Effects of enrofloxacin treatment on the bacterial microbiota of milk from goats with persistent mastitis

Antibiotic resistance has become a major concern for human and animal health. As fluoroquinolones have been extensively used in human and veterinary medicine, there has also been the rapid emergence and spread of antimicrobial resistance around the world. Here, we analysed the microbiome of goat milk using samples from healthy goats and those diagnosed with persistent mastitis and treated using the antibiotic enrofloxacin with 16S rRNA amplicon sequencing. We selected a group of 11 goats and 22 samples of milk that did not respond clinically to enrofloxacin treatment. Milk samples were evaluated before and after treatment to verify changes of the microbiota; the three first lactating goats were selected from the healthy control group. The milk samples from the healthy control animals presented a larger abundance of different species of bacteria of the Staphylococcus genus, but a smaller number of different genera, which indicated a more specific niche of resident bacteria. The Firmicutes phylum was predominantly different between the studied groups. Samples from before-treatment animals had a higher number of new species than those from the control group, and after being treated again. These microbiota received new bacteria, increasing the differences in bacteria even more in relation to the control group. Genotypes such as Trueperella and Mannheimia, between other genera, had a high abundance in the samples from animals with persistent mastitis. The dysbiosis in this study, with marked evidence of a complex microbiota in activity in cases of the failure of antimicrobial treatment for persistent chronic mastitis, demonstrates a need to improve the accuracy of pathogen identification and increases concern regarding antibiotic treatments in milk production herds.

Coupled changes of bacterial community and function in the gut of mud crab (Scylla Paramamosain) in response to Baimang disease

Increasing evidence has revealed a close association between intestinal bacterial community and hosts health. However, it is unclear whether and what extend Baimang disease alters the intestinal microbiota in mud crab (Scylla paramamosain). Here, we conducted intestinal contents Illumina sequencing of healthy and Baimang diseased mud crab (S. paramamosain) to understand bacterial community variations among health status. In addition, bacterial functional predication was used to investigate whether and how the bacteria variations further change their functions? The phyla of Proteobacteria, Fusobacteria, Cyanobacteria, Tenericutes, Firmicutes, Bacteroidetes, and Spirochaetae constituted over 96.44% of the total intestinal bacteria, with being the dominant taxa. The 7 most significantly different orders, including the increased four orders of Clostridiales, Entomoplasmatales, Bacteroidales, and Mycoplasmatales and the decreased three orders of Vibrionales, Campylobacterales, and Fusobacteriales, accounted for 61.14% dissimilarity, probably being the indicator taxa of Baimang disease. Accordingly, 12 Kyoto Encyclopedia of Genes and Genomes orthologies in level 3 shifted significantly at the diseased crabs. Especially, bacterial secretion system, secretion system, lipopolysaccharide biosynthesis proteins and Vibrio cholerae pathogenic cycle, being related to bacterial virulence, were reduced. In addition, the reduced butanoate metabolism, and induced methane metabolism and one carbon pool by folate were important metabolic processes of probiotic, such as Bacteroides spp. and Clostridium spp., with playing critical roles in host health. This study suggests that Baimang disease coupled altered the intestinal bacterial communities and functions, providing timely information for further analysis the influencing mechanism of Baimang disease in mud crab (S. paramamosain).

Obesity, diabetes, and the gut microbiome: an updated review

Obesity and diabetes are two of the most prevalent health problems and leading causes of death globally. As research on the intestinal microbiome increases, so does our understanding of its intricate relationship to these diseases, although this has yet to be fully elucidated. Areas covered: This review evaluates the role of the gut microbiome in obesity and diabetes, including the influences of internal and environmental factors. Literature searches were performed using the keywords 'diabetes,' 'insulin resistance,' 'gut microbiome,' 'gut microbes,' 'obesity,' and 'weight gain.' Expert commentary: Highlights of recent research include new findings regarding the effects of caloric restriction, which expound the importance of diet in shaping the gut microbiome, and studies reinforcing the lasting implications of antibiotic use for diabetes and obesity, particularly repeated doses in early childhood. Mechanistically, interactions between the microbiome and the host innate immune system, mediated by TLR4-LPS signaling, have been shown to meditate the metabolic benefits of caloric restriction. Further, gut microbes haven now been shown to regulate oxygen availability via butyrate production, thus protecting against the proliferation of pathogens such as E. coli and Salmonella. However, many microbial metabolites remain unidentified and their roles in obesity and diabetes remain to be determined.

Selection of a cut-off for high- and low-methane producers using a spot-methane breath test: results from a large north American dataset of hydrogen, methane and carbon dioxide measurements in breath

BACKGROUND

Levels of breath methane, together with breath hydrogen, are determined by means of repeated collections of both, following ingestion of a carbohydrate substrate, at 15-20 minutes intervals, until 10 samples have been obtained. The frequent sampling is required to capture a rise of hydrogen emissions, which typically occur later in the test: in contrast, methane levels are typically elevated at baseline. If methane emissions represent the principal objective of the test, a spot methane test (i.e. a single-time-point sample taken after an overnight fast without administration of substrate) may be sufficient.

METHODS

We analysed 10-sample lactulose breath test data from 11 674 consecutive unique subjects who submitted samples to Commonwealth Laboratories (Salem, MA, USA) from sites in all of the states of the USA over a one-year period. The North American Consensus (NAC) guidelines criteria for breath testing served as a reference standard.

RESULTS

The overall prevalence of methane-positive subjects (by NAC criteria) was 20.4%, based on corrected methane results, and 18.9% based on raw data. In our USA dataset, the optimal cut-off level to maximize sensitivity and specificity was ≥4 ppm CH4, 94.5% [confidential interval (CI): 93.5-95.4%] and 95.0% (CI: 94.6-95.5%), respectively. The use of a correction factor (CF) (5% CO2 as numerator) led to reclassifications CH4-high to CH4-low in 0.7 % and CH4-low to CH4-high in 2.1%.

CONCLUSIONS

A cut-off value for methane at baseline of either ≥4 ppm, as in our USA dataset, or ≥ 5 ppm, as described in a single institution study, are both highly accurate in identifying subjects at baseline that would be diagnosed as 'methane-positive' in a 10-sample lactulose breath test for small intestinal bacterial overgrowth.