Certain gastrointestinal diseases have been associated with positive methane producer status, including colon cancer. As early as in , Heins and his colleagues 44 showed that the number of methane producers among patients with colorectal cancer occluding the left colon was double than that of the general population, indicating a possible relation between methane production and colon cancer.
However, following this observation there were only two more small studies in favor of this association while 10 studies failed to confirm it, as illustrated by Roccarina et al. Recent data 48 has challenged the perception that methane and slowed intestinal motility just coexist or that the abundance of methane is secondary to impaired intestinal motility and proposed that there is a causative relation of methane production and intestine motility disturbance.
The consistency of the motility findings in response to methane in the animal models and in human subjects provided for the first time experimental evidence that methane may not be an inert intestinal gas, but it can intervene to the neuromuscular function of the intestinal track. Moreover, the results in the isolated ileum segment of the guinea pig experiment support a topical than a brain-gut axis methane action. The evidence for rather causative association of methane with delayed intestinal motility was further augmented by an elegant experiment that aimed to further explore possible effects of gases produced in the intestine in the ileum and colon motility.
Investigators showed in an ex vivo experiment using guinea pig ileal, right and left colon segments in a peristaltic tissue bath that: 1 ileal contractile activity significantly decreased and the amplitude of peristaltic contractions increased when methane was pumped in the bath, while the opposite phenomenon was detected after H 2 infusion; 2 colonic transit was shortened by hydrogen infusion, but this effect was diminished when methane was additionally pumped; these effects being more prominent in the right colon.
Although there are limitations in animal and gas perfusion studies to mimic the physiological status of the intestinal environment, these two translational studies provide experimental evidence to support a direct action of methane to delay intestinal transit time.
Intestinal transit time is a physiological marker of intestinal motility. It can be measured by different ways, e. Table 3 summarizes seven adult 30 , 31 , 51 - 55 studies that included and methane producers and non-producers, respectively. There is a clear association of methane production and slow intestinal transit, irrespective of health status healthy, IBS or constipated individuals and of the method used to assess transit in all of them.
Even in the two studies 31 , 52 in which statistical significance was not reached, a numerical difference was detected. MP, methane producers; MnP, methane non-producers; bm, bowel movements. There are two more studies that due to different estimation of intestinal motility-using the motility index 48 , 56 -are not included in the Table 3. Both studies showed that methane breath test positivity was related to higher fasting motility index, while the study of Pimentel et al 48 showed a higher postprandial motility index in methane producing subjects, as well.
Therefore, data universally support that production of methane as determined by breath testing, is associated with delayed intestinal transit.
However, the mechanisms of transit delay induced by methane are still unclear. A small study that evaluated 18 Rome I IBS patients 4 methane producers showed that the postprandial serotonin level in methane producing patients was lower than in hydrogen producers, implicating methane to serotonin production for the regulation of intestinal motility.
IBS is the most common functional disorder characterized by the presence of abdominal pain and altered bowel habits. Overall, the prevalence of methane producers among IBS sufferers varies. It ranges from low Table 4 summarizes studies supporting an association of methane and constipation related disorders: C-IBS and chronic constipation.
Furthermore, a study that assessed among many other parameters, stool frequency and consistency, showed that Rome II IBS methane predominant producers on sucrose breath testing reported more often less than three defecation per week and hard or lumpy stools compared to hydrogen producers. However, investigators revealed a weak association between methane positivity and bloating, flatulence and abdominal pain.
To the best of our knowledge so far, this is the only study that has not revealed an association between methane breath test positivity and constipation in IBS. However, the authors acknowledge that the study design incorporated a broad subjective definition of constipation without measuring stool frequency and consistency which might be responsible for the discrepant results.
Since there is no a specific examination, not even a surrogate marker, for the diagnosis of IBS, this diagnosis of the syndrome is symptom based, as proposed by the Rome Foundation. Indeed, a prospective, double blind, head to head comparison of methane positivity in lactulose breath test and Rome I IBS classification showed that methane positivity had a sensitivity of More importantly, the association remained significant OR, 3.
However before adopting a diagnostic strategy like that, we must have in mind that methane is present in a certain proportion in healthy individuals, methane does not account for all constipation, there are constipated and C-IBS patients without production of methane in the breath test and therefore, methane cannot be considered the exclusive cause of the symptoms.
Beyond constipation or diarrhea, IBS is a "constellation" of symptoms rather than a single predominant symptom. Patients answered a 31 item questionnaire on the severity of their gastrointestinal symptoms and underwent a lactulose breath test.
The study showed that IBS methane producers have a different set of symptoms constipation, small bowel movements, straining, lack of milk intolerance and lack of weight loss as compared to non-producers diarrhea, pain during and after defecation, large and foul smelling stool, urgency and weakness after the defecation proposing again a biomarker role for IBS in order to provide patients treatment beyond laxatives for constipation.
A further step toward the clarification of methane's role in IBS was made by identifying the incidence and type of methanogens in C-IBS patients. However, absolute counts and relative to other stool bacteria proportion of the archaeon were significantly higher in methane positive patients. Furthermore, the quantity of M. Antibiotic treatment of IBS with poorly absorbable antibiotics has gained scientific attention during the last decade. After the original trial with neomycin, 68 three fully-published and one in abstract form, double blind, placebo controlled trials of rifaximin 69 - 72 suggest an improvement in IBS symptoms related to SIBO eradication.
In a sub-analysis of the neomycin trial, 73 there were 12 methane positive patients among the original study participants and all of them belonged to C-IBS group. In further work, the same group performed a retrospective analysis of treatment data among C-IBS patients. These 2 treatment studies, although they have certain limitation regarding design, clinical outcome definition and small number of included patients, provide further evidence for the use of breath test methane positivity as a biomarker to identify C-IBS patients that may benefit from antibiotic treatment.
Moreover, this biomarker can provide objective monitoring of the treatment effect, since the clinical response correlates with methane elimination. Chronic constipation is another bowel functional disorder which is broadly divided into normal and slow transit constipation and in evacuation disorders.
The relation of methane production and functional constipation has also been examined, albeit less than in IBS. In a study of 96 Rome III chronic constipation patients and controls, symptoms were evaluated using questionnaire, methane positivity was examined using glucose breath testing and colon transit time was measured using radiopaque markers.
Methane production was highest in the ST followed by the NT patients and it correlated with colon transit time. In another retrospective study, 62 Rome III constipated patients and 49 controls had lactulose breath testing for methane production and an accurate colon transit time measurement with markers.
Investigators showed that breath methane was positive in However, methane positivity was not related with stool consistency.
Furthermore, investigators did not reveal any relationship between methane production and anorectal manometry findings. Using a different approach, the association of CH 4 production and various functional gastrointestinal symptoms was studied prospectively in a set of patients and 40 controls, using questionnaire symptom assessment and glucose breath test.
Regression analysis revealed that methane excretion was related only to constipation. When constipated patients were divided in those with chronic constipation and C-IBS, methane production was higher in the chronic constipation patients In contrast to C-IBS methane eradication treatment data, there is absence of trials evaluating the effects of antibiotic treatment in methane production and symptom resolution in functional constipation.
There is only one case report 77 of a patient with slow transit constipation and methane positivity while fasting and after glucose ingestion whose stool frequency and consistency improved, and colon transit accelerated after 14 days treatment with refaximin mg t. Gastroparesis symptoms include postprandial fullness, early satiety, abdominal pain, nausea, vomiting and bloating without obstruction.
It may be idiopathic or secondary to diabetes mellitus, gastric-surgical procedures and opioid consumption etc. Although the evidence is still poor to reach firm conclusions, we report herein the only two available studies that have evaluated methane production in gastroparesis patients. Methane is a unique gas produced in strict anaerobic conditions by intestinal methanogens that metabolize H 2 , one of the end products of bacterial fermentation.
Although thought of as an inert gas, there is evidence from translational medicine that methane acts like a neuromuscular transmitter resulting in reduced propagation of the peristaltic movement in the intestine. This evidence is further supported by the universal finding in physiological studies that CH 4 production measured by breath testing delays transit time and by clinical studies showing a relationship between methane status on breath testing with delayed transit associated conditions like constipation predominant IBS and chronic constipation.
There is also preliminary evidence that antibiotic treatment results in improvement of symptoms in a certain proportion of patients suffering from these disorders in a fashion related to its ability to eradicate methane. However, methane is also detected in healthy individuals and all constipation patients and symptoms are not associated with high methane production, meaning that there is plenty of room for research to identify the mechanism of action of methane on intestinal motility before recommending methane as a biomarker for the diagnosis of constipation related disorders or as a biomarker for selecting patients who may benefit from antibiotic eradication of methane.
Financial support: None. Conflicts of interest: None. Author contributions: Konstantinos Triantafyllou designed, drafted and finally approved the manuscript. Christopher Chang designed, reviewed the manuscript for intellectual content and finally approved it. Mark Pimentel conceived the idea, reviewed the manuscript for intellectual content and finally approved it.
National Center for Biotechnology Information , U. Journal List J Neurogastroenterol Motil v. J Neurogastroenterol Motil. Published online Dec Find articles by Konstantinos Triantafyllou. Find articles by Christopher Chang. Find articles by Mark Pimentel. Author information Article notes Copyright and License information Disclaimer. Corresponding author. This article has been cited by other articles in PMC. Abstract Anaerobic fermentation of the undigested polysaccharide fraction of carbohydrates produces hydrogen in the intestine which is the substrate for methane production by intestinal methanogens.
Introduction The composition of gases generated in the intestine shows both inter-individual variability and variability among the different anatomical sites of the gastrointestinal tract. Methanogens Among the numerous microorganisms that outnumber eukaryotic cells in human gut, methanogens are primitive "bugs" belonging to the Kingdom Archaea, one of the three distinct branches of the phylogenetic evolutionary descent; bacteria and eukaryota being the other two.
Table 1 Detection of Methanogens in Healthy Humans. Open in a separate window. PCR, polymerase chain reaction. Ferraretto, L. Effect of direct-fed microbial supplementation on lactation performance and total-tract starch digestibility by midlactation dairy cows. Flythe, M. The effect of pH and a bacteriocin bovicin HC5 on Clostridium sporogenes MD1, a bacterium that has the ability to degrade amino acids in ensiled plant materials.
FEMS Microbiol. Forde, B. Genome sequences and comparative genomics of two Lactobacillus ruminis strains from the bovine and human intestinal tracts. Cell Fact. Frizzo, L. Effect of lactic acid bacteria and lactose on growth performance and intestinal microbial balance of artificially reared calves. Garsa, A. Bovicins: the bacteriocins of streptococci and their potential in methane mitigation. Probiotics Antimicrob Proteins doi: Effects of intravaginal lactic acid bacteria on bovine endometrium: implications in uterine health.
Ghorbani, G. Effects of bacterial direct-fed microbials on ruminal fermentation, blood variables, and the microbial populations of feedlot cattle. Gollop, N. Antibacterial activity of lactic acid bacteria included in inoculants for silage and in silages treated with these inoculants. Hammes, W. The sensitivity of the pseudomurein-containing genus Methanobacterium to inhibitors of murein synthesis. Henderson, G. Rumen microbial community composition varies with diet and host, but a core microbiome is found across a wide geographical range.
Hristov, A. Special topics—Mitigation of methane and nitrous oxide emissions from animal operations: I. A review of enteric methane mitigation options. Huck, G. Effects of feeding two microbial additives in sequence on growth performance and carcass characteristics of finishing heifers.
Kansas Agric. Station Res. Hudson, J. Identification and enumeration of oleic acid and linoleic acid hydrating bacteria in the rumen of sheep and cows.
Conversion of oleic acid to hydroxystearic acid by two species of ruminal bacteria. Iverson, W. Bacteriocins of Streptococcus bovis. Janssen, P. Structure of the archaeal community of the rumen. Jeyanathan, J. Bacterial direct-fed microbials fail to reduce methane emissions in primiparous lactating dairy cows.
Sci Biotech. The use of direct-fed microbials for mitigation of ruminant methane emissions: a review. Animal 8, — Screening of bacterial direct-fed microbials for their antimethanogenic potential in vitro and assessment of their effect on ruminal fermentation and microbial profiles in sheep.
Kamke, J. Rumen metagenome and metatranscriptome analyses of low methane yield sheep reveals a Sharpea -enriched microbiome characterised by lactic acid formation and utilisation. Microbiome Kelly, W. Chromosomal diversity in Lactococcus lactis and the origin of dairy starter cultures. Genome Biol. Klieve, A. Genetic homogeneity and phage susceptibility of ruminal strains of Streptococcus bovis isolated in Australia.
Inducible bacteriophages from ruminal bacteria. Klostermann, K. Intramammary infusion of a live culture of Lactococcus lactis for treatment of bovine mastitis: comparison with antibiotic treatment in field trials.
Knapp, J. Invited review: enteric methane in dairy cattle production: quantifying the opportunities and impact of reducing emissions. Krehbiel, C. Bacterial direct-fed microbials in ruminant diets: performance response and mode of action.
Kung, L. Effect of microbial inoculants on the nutritive value of corn silage for lactating dairy cows. Animal Response to Silage Additives. Leahy, S. The complete genome sequence of Methanobrevibacter sp. Lee, S. The effect of bovicin HC5, a bacteriocin from Streptococcus bovis HC5, on ruminal methane production in vitro. Lettat, A. Rumen microbial and fermentation characteristics are affected differently by bacterial probiotic supplementation during induced lactic and subacute acidosis in sheep.
BMC Microbiol. Mangoni, M. Short native antimicrobial peptides and engineered ultrashort lipopeptides: similarities and differences in cell specificities and modes of action. Life Sci. Mantovani, H. The antibacterial activity and sensitivity of Streptococcus bovis strains isolated from the rumen of cattle. Maragkoudakis, P. Feed supplementation of Lactobacillus plantarum PCA modulates gut microbiota and milk fatty acid composition in dairy goats—a preliminary study.
Food Microbiol. A new probiotic and bacteriocin-producing strain of Enterococcus faecium EF and its use in grass ensiling. Czech J. Marounck, M. Influence of culture Eh on the growth and metabolism of the rumen bacteria Selenomonas ruminantium , Bacteroides amylophilus , Bacteroides succinogenes and Streptococcus bovis in batch culture. Morvan, B. Hydration of oleic acid by Enterococcus gallinarum , Pediococcus acidilactici and Lactobacillus sp. Anaerobe 5, — Muck, R. Inoculant effects on alfalfa silage: In vitro gas and volatile fatty acid production.
Silage review: recent advances and future uses of silage additives. Mwenya, B. Noel, S. Nollet, L. Effect of the addition of Peptostreptococcus productus ATCC on reductive acetogenesis in the ruminal ecosystem after inhibition of methanogenesis by cell-free supernatant of Lactobacillus plantarum Opio, C.
Oxford, A. The nutritional requirements of rumen strains of Streptococcus bovis considered in relation to dextran synthesis from sucrose. Payandeh, S. Probiotic supplementation effects on milk fatty acid profile in ewes. Philippeau, C. Effects of bacterial direct-fed microbials on ruminal characteristics, methane emission, and milk fatty acid composition in cows fed high- or low-starch diets. Raeth-Knight, M. Effect of direct-fed microbials on performance, diet digestibility, and rumen characteristics of Holstein dairy cows.
Rainard, P. A critical appraisal of probiotics for mastitis control. Reilly, K. Reisinger, A. How much do direct livestock emissions actually contribute to global warming? Change Biol. Renuka, Puniya, M. Influence of pediocin and enterocin on in-vitro methane, gas production and digestibility. Russell, J. Substrate preferences in rumen bacteria: evidence of catabolite regulatory mechanisms. The bacteriocins of ruminal bacteria and their potential as an alternative to antibiotics.
Salvetti, E. Reclassification of Lactobacillus catenaformis Eggerth Moore and Holdeman and Lactobacillus vitulinus Sharpe et al. They then checked DNA data and found the genes that produce iron-only nitrogenase in several — indicating that they too are unacknowledged sources of methane.
Originally published by Cosmos as Some species of bacteria produce methane. Cosmos is published by The Royal Institution of Australia, a charity dedicated to connecting people with the world of science.
Financial contributions, however big or small, help us provide access to trusted science information at a time when the world needs it most. Please support us by making a donation or purchasing a subscription today. Cosmos » Chemistry » Some species of bacteria produce methane Share Tweet.
Nitrogen-fixing bacteria inside soybean cells. Andrew Masterson Andrew Masterson is a former editor of Cosmos.
0コメント