Potentially toxic metals (PTM), along with PTM-resistant bacteria and PTM-resistance genes, may be introduced into soil and water through sewage systems, direct excretion, land application of biosolids (organic matter recycled from sewage, especially for use in agriculture) or animal manures as fertilizers, and irrigation with wastewater or treated effluents. In this review article, we have evaluated whether the content of arsenic (As), cadmium (Cd), chromium (CrIII + CrVI), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), and zinc (Zn) in soil and fertilizing products play a role in the development, spreading, and persistence of bacterial resistance to these elements, as well as cross- or co-resistance to antimicrobial agents. Several of the articles included in this review reported the development of resistance against PTM in both sewage and manure. Although PTM like As, Hg, Co, Cd, Pb, and Ni may be present in the fertilizing products, the concentration may be low since they occur due to pollution. In contrast, trace metals like Cu and Zn are actively added to animal feed in many countries. In several studies, several different bacterial species were shown to have a reduced susceptibility towards several PTM, simultaneously. However, neither the source of resistant bacteria nor the minimum co-selective concentration (MCC) for resistance induction are known. Co- or cross-resistance against highly important antimicrobials and critically important antimicrobials were identified in some of the bacterial isolates. This suggest that there is a genetic linkage or direct genetic causality between genetic determinants to these widely divergent antimicrobials, and metal resistance. Data regarding the routes and frequencies of transmission of AMR from bacteria of environmental origin to bacteria of animal and human origin were sparse. Due to the lack of such data, it is difficult to estimate the probability of development, transmission, and persistence of PTM resistance. Abbreviations: PTM: potentially toxic metals; AMR: antimicrobial resistance; ARG: antimicrobial resistance gene; MCC: minimum co-selective concentration; MDR: multidrug resistance; ARB: antimicrobial resistant bacteria; HGT: horizontal gene transfer; MIC: minimum inhibitory concentration.
The gut–brain axis and the microbiome have recently acquired an important position in explaining a wide range of human behaviours and emotions. Researchers have typically presented developments in understandings of the microbiome as radical and new, offering huge potential for better understandings of our bodies and what it means to be human. Without refuting the value of this research, this article insists that, traditionally, doctors and patients acknowledged the complex interactions between their guts and emotions, although using alternative models often based on nerves or psychology. For example, nineteenth-century doctors and patients would have been well acquainted with the idea that their stomachs and minds were somehow connected, and that this interaction could produce positive or negative physical and mental health impacts. To demonstrate this, this article offers a snapshot of medical and public thought on (what we currently call) the gut–brain axis in the nineteenth and twentieth centuries, using Britain as a key case study due to the prevalence of gastric problems in that country. It commences by exploring how nineteenth-century doctors and patients took for granted the intimate relations between gut and mind and used their ideas on this to debate personal health, medical theory and social and political discourse. The article then moves on to argue that various medical sub-disciplines emerged (anatomy, physiology, surgery) that threatened to reduce the stomach to a physiologically complex organ but, in doing so, inadvertently began to erase ideas of a gut–mind connection. However, these new models proved unsatisfactory, allowing more holistic ideas of the body–mind relationship to continue to carry currency in twentieth-century psychological and medical thought. In the late century, pharmacological developments once again threatened to minimise the gut–brain axis, before it once again became popular in the early twenty-first century, now debated through a new language of microbiology.
Background: Nutrient and energy metabolism in human colon depends on bacterial growth rate that is determined by the colonic transit rate. Objective: A novel approach, De-stat culture was used to distinguish the fast and slow growing sub-populations from fecal microbiota. Design: The enrichment and metabolism of bacteria from pooled fecal cultures of children was studied at dilution rates D = 0.2-0.0 1/h in mucin-supplemented media containing either arabinogalactan or apple pectin. Results: The study revealed clear differentiation of the fecal microbiota at higher (above 0.1 1/h) and lower (below 0.1 1/h) dilution rates, along with metabolic changes. Similarity of the fast and slow growing bacteria was observed in two different fecal pools and on both substrates, suggesting the dilution rate as the main triggering parameter for selection of bacteria. At high dilution rates, the species Collinsella aerofaciens, Dorea longicatena, Escherichia coli, Lachnoclostridium torques, and different Bacteroides (B. caccae, B. fragilis, B. ovatus, B. thetaiotaomicron, B. vulgatus) were dominant in both media variants. At low dilution rates, Akkermansia muciniphila, Eisenbergiella tayi, Negativicoccus succinivorans, and a group of Ruminococcaceae became dominant in both media and in both fecal pools. This change in bacterial population accompanied by the increased production of propionic and butyric acids as well as higher consumption of alanine and branched chain amino acids at low dilution rates. Conclusions: The study suggests that specific growth rate has important effect on the dynamics of colon microbiota. Manipulation of the proportions of fast and slow growing gut bacteria through modulation of the transit rate could be a target in human nutrition studies. The De-stat study would enable to predict changes in microbiota composition associated with the decrease or increase of the colonic transit rate.
This article focuses on autointoxication, a discredited medical theory from the late nineteenth century that provides important points of reflection for today's research on the role of microbes in the human gut for mental health. It considers how the theory of autointoxication, which came into great prominence amongst physicians and the general public worldwide, fell from grace by the middle of the twentieth century, and briefly asks why studies of the human microbiome are now back in vogue. It departs from earlier articles on the topic firstly by arguing that autointoxication theory was especially prevalent in France, and secondly by focusing on the application of this theory to mental health. Bringing to light medical treatises and theses from this period which have so far remained unexamined, it shows that examining the development and reception of medical theories form the past can help us today in understanding both the pitfalls and promise of research in this area.
Background: In recent decades, dominant models of mental illness have become increasingly focused on the head, with mental disorders being figured as brain disorders. However, research into the active role that the microbiome-gut-brain axis plays in affecting mood and behaviour may lead to the conclusion that mental health is more than an internalised problem of individual brains. Objective: This article explores the implications of shifting understandings about mental health that have come about through research into links between the gut microbiome and mental health problems such as depression and anxiety. It aims to analyse the different ways that the lines between mind and body and mental and physical health are re-shaped by this research, which is starting to inform clinical and public understanding. Design: As mental health has become a pressing issue of political and public concern it has become increasingly constructed in socio-cultural and personal terms beyond clinical spaces, requiring a conceptual response that exceeds biomedical inquiry. This article argues that an interdisciplinary critical medical humanities approach is well positioned to analyse the impact of microbiome-gut-brain research on conceptions of mind. Results: The entanglement of mind and matter evinced by microbiome-gut-brain axis research potentially provides a different way to conceptualise the physical and social concomitants of mental distress. Conclusion: Mental health is not narrowly located in the head but is assimilated by the physical body and intermingled with the natural world, requiring different methods of research to unfold the meanings and implications of gut thinking for conceptions of human selfhood.
s, book chapters and reports. He is still involved in many research projects. The journal would like to congratulate its former Editor-in-Chief for receiving the noble recognition from theKing ofNorway. Themicrobeswould probably like to congratulate aswell: they have all reasons to celebrate that their good old friend – who has always guarded them as a holy grail – finally has become a true knight! Disclosure statement No potential conflict of interest was reported by the author.
The gut–brain axis and the microbiome have recently acquired an important position in explaining a wide range of human behaviours and emotions. Researchers have typically presented developments in understandings of the microbiome as radical and new, offering huge potential for better understandings of our bodies and what it means to be human. Without refuting the value of this research, this article insists that, traditionally, doctors and patients acknowledged the complex interactions between their guts and emotions, although using alternative models often based on nerves or psychology. For example, nineteenthcentury doctors and patients would have been well acquainted with the idea that their stomachs and minds were somehow connected, and that this interaction could produce positive or negative physical and mental health impacts. To demonstrate this, this article offers a snapshot of medical and public thought on (what we currently call) the gut–brain axis in the nineteenth and twentieth centuries, using Britain as a key case study due to the prevalence of gastric problems in that country. It commences by exploring how nineteenth-century doctors and patients took for granted the intimate relations between gut and mind and used their ideas on this to debate personal health, medical theory and social and political discourse. The article then moves on to argue that various medical sub-disciplines emerged (anatomy, physiology, surgery) that threatened to reduce the stomach to a physiologically complex organ but, in doing so, inadvertently began to erase ideas of a gut–mind connection. However, these new models proved unsatisfactory, allowing more holistic ideas of the body–mind relationship to continue to carry currency in twentieth-century psychological and medical thought. In the late century, pharmacological developments once again threatened to minimise the gut–brain axis, before it once again became popular in the early twenty-first century, now debated through a new language of microbiology. ARTICLE HISTORY Received 31 August 2018 Revised 18 October 2018 Accepted 25 October 2018
This special edition on humanistic approaches to the microbiota–gut–brain axis was inspired by two symposia organised by literary scholar Dr Manon Mathias at the University of Aberdeen in 2017 and ...
In this paper, some of the medical literature on the historical disease-concept of 'neurasthenia gastrica' is reviewed. Neurasthenia gastrica was defined as a sub-unit of the wider category of neurasthenia, also referred to as nervous exhaustion or nervous weakness. Neurasthenia was a commonly used diagnostic label at the end of the nineteenth century and a few decades onwards, and was used to describe a wide variety of symptoms for which no 'organic' basis could be found. In neurasthenia gastrica, however, the gastrointestinal symptoms predominated, and there was considerable debate as to how the gut interacted with the central nervous system in the development of these ailments. Some of these discussions may be seen as historical precedents for the current debates on the brain-gut-microbiota axis, particularly in relation to the so-called functional gastrointestinal disorders.
This paper presents the Mind the Gut exhibition, opened in 2017 at the Medical Museion, the University of Copenhagen's museum for the culture and history of medicine. It is an experimental exhibition combining science, art, and history in an examination of the relationship between mind and gut, including the trillions of microbes that inhabits them. Mind the Gut was the result of a 2-year-long research and curatorial process, which began in 2015 when Museion was awarded the Bikuben Foundation Vision Award. The exhibition brings together the long history of attempts to understand and intervene in the relationship between mind and gut, between emotions and digestion with cutting-edge biomedical research, and includes the perspectives of science, medicine, and personal experience, via a combination of artworks, historical objects from the Medical Museion collections, items from laboratories, and individual stories. The exhibition is organized around different ways the body has been handled in order to intervene in interactions between mind, gut, and bacteria, including imaging, electrifying, feeding, drugging, and opening surgically. This paper outlines some of the thoughts on science communication that motivated the exhibition, discussing why the displays emphasize the exploratory over the explanatory. Also discussed are several artistic collaborations that formed part of the displays. Ultimately, Mind the Gut is created to be a public space that encourages reflection and curiosity, by showing how biomedicine fits into social, cultural, historical, and directly personal contexts. The exhibition does not aim to provide answers about what food the visitors should eat or what the truth of how gut and brain interactions might be. Rather, it emphasizes process over result, hopefully encouraging the visitors to ask their own questions of the relationship between mind and gut, between body and microbes.
This paper shows how Austrian psychiatrists of the 1870s developed the first pathological accounts of institutional coprophagia, examining how they related the behaviour to mental illness and dementia. These ideas about coprophagia contrasted dramatically to the long European pharmacological tradition of using excrement for the treatment of a wide range of health conditions. Recent medical scholarship on institutional coprophagia is also reviewed here, with a novel hypothesis proposed about why some patients in long-term care resort to the behaviour in institutions where there is little opportunity for healthy human–microbe interactions.
Welcome to a one-day symposium in our series ‘Science meets Industry’. As indicated in the title, the focus will be on whether and to what extent our food can influence health, especially the mood. This is indeed a topical question: in parallel with the increasing concern about so-called lifestyle diseases and syndromes, there has been an increased interest in possible preventive dietary regimens. Today we will not focus on any regimens; we will focus on one key compound from each of our three major dietary groups, i.e. carbohydrates, protein and fat. The overall intention is to reduce the gap between basic science and the food industry.
Objective: Alterations of gut microbiota composition or function may participate in the pathophysiology of several diseases. We aimed to explore the effect of chronic alcohol overconsumption on gut microbial metabolism, as assessed by evaluating 13C-D-xylose breath test results. Materials and methods: We investigated all 13C-D-xylose breath tests performed at Lovisenberg Diaconal Hospital during the years 2005 to 2011, using patient files for diagnosing the patients into one of three patient categories: alcohol overconsumption, coeliac disease and functional bowel disorder. In addition, a group of healthy controls was included. The time curves of 13CO2 excretion in breath samples were divided into two phases, evaluating small intestinal absorption (0–60 min) and colonic microbial metabolism (90–240 min), respectively. Results: A total of 719 patients underwent 13C-D-xylose breath testing during the inclusion period. Thirty-five had a history of alcohol overconsumption, 66 had coeliac disease, and 216 had a functional bowel disorder, while 44 healthy controls were included for comparison. The alcohol overconsumption group had similar small intestinal phase results as the group of patients with untreated coeliac disease. During the colonic phase, the group of patients with alcohol overconsumption differed from all the other groups in terms of 13C-xylose recovery, with significantly less 13CO2 excretion compared to the other groups. Conclusion: The results suggest that patients with a history of alcohol overconsumption suffer from both small intestinal malabsorption and impaired colonic microbial metabolism. The role of gut microbiota in chronic alcohol overconsumption should be investigated further.
The gut microbiota is considered an organ that co-develops with the host throughout its life. The composition and metabolic activities of the gut microbiota are subject to a complex interplay between the host genetics and environmental factors, such as lifestyle, diet, stress and antimicrobials. It is evident that certain prebiotics, and antimicrobials produced by lactic acid bacteria (LAB), can shape the composition of the gut microbiota and its metabolic activities to promote host health and/or prevent diseases. In this review, we aim to give an overview of the impact of prebiotic fibres, and bacteriocins from LAB, on the gut microbiota and its activities, which affect the physiology and health of the host. These represent two different mechanisms in modulating the gut microbiota, the first involving exploitative competition by which the growth of beneficial bacteria is promoted and the latter involving interference competition by which the growth of pathogens and other unwanted bacteria is prevented. For interference competition in the gut, bacteriocins offer special advantages over traditional antibiotics, in that they can be designed to act towards specific unwanted bacteria and other pathogens, without any remarkable collateral effects on beneficial microbes sharing the same niche.
Background: Colorectal cancer (CRC) is one of the most common cancer types worldwide. The role of the intestinal microbiota in CRC, however, is not well established. In particular, the co-variation between age, tumor progression and microbiota remains largely unknown. Objective and design: We therefore used a recently developed A/J Min/+ mouse model resembling human CRC to investigate how microbial composition in cecum correlates with tumor progression, butyrate and age. Results: We found that the association between the gut microbiota and tumor load was stronger, by far, than the association with both butyrate and age. The strongest direct tumor association was found for mucosal bacteria, with nearly 60% of the significantly correlating operational taxonomic units being correlated with CRC tumor load alone. Conclusion: We favor a systemic association between tumor load and microbiota, since the correlations are associated with tumor load in gut segments other than the cecum (both small and large intestine).
Background: Bacterial vaginosis is the most frequent condition associated to the vaginal microbiota imbalance, affecting about the 40-50% of women in the world. Even if antibiotics are effcetive for bacterial vaginosis treatment a long-term recurrence rates, higher than 70%, is recorded. Lactoferrin is an iron-binding glycoprotein with bacteriostatic and bactericidal properties. It owns the ability to protect the host against infection, by binding and regulating the iron needed for the bacterial proliferation. Objective: The present study was an open prospective randomized trial (registration no. SHI-EVE-2014.01) aimed at characterizing the bacterial biota of women affected by bacterial vaginosis (BV) and assessing the effects of two different lactoferrin concentrations (100 mg and 200 mg vaginal pessaries) on the composition and dynamics of the vaginal bacterial biota. Design: Sixty women with BV were recruited and randomized into two groups to receive lactoferrin pessaries for 10 days. Clinical evaluation was based on Amsel criteria and Nugent scores. Culture-dependent methods and Ion Torrent PGM sequencing of the 16S rRNA gene were applied to study in depth the overall structure of the vaginal bacterial biota and its dynamics during the treatment. Results: Vaginal lactoferrin administration modified the vaginal microbiota composition in patients with BV. During treatment, both 100 mg and 200 mg lactoferrin vaginal pessaries significantly decreased the occurrence of bacteria associated with BV, such as Gardnerella, Prevotella, and Lachnospira, and increased the occurrence of Lactobacillus species. The bacterial biota balance was maintained up to 2 weeks after treatment only in women treated with 200 mg lactoferrin pessaries. Conclusions: This study indicates that lactoferrin could be proposed as an alternative therapeutic approach for BV. Our data showed, for the first time, the dominance of Lactobacillus helveticus species during and after vaginal lactoferrin treatment.
It has been established that the human gut microbiome is commensal, helps to digest our food, and is involved in metabolic processes in the gut and in the development and maintenance of our immune ...
Background: Permafrost preserves a variety of viable ancient microorganisms. Some of them can be cultivated after being kept at subzero temperatures for thousands or even millions of years. Objective: To cultivate bacterial strains from permafrost. Design: We isolated and cultivated two bacterial strains from permafrost that was obtained at Mammoth Mountain in Siberia and attributed to the Middle Miocene. Bacterial genomic DNA was sequenced with 40–60× coverage and high-quality contigs were assembled. The first strain was assigned to Staphylococcus warneri species (designated MMP1) and the second one to Staphylococcus hominis species (designated MMP2), based on the classification of 16S ribosomal RNA genes and genomic sequences. Results: Genomic sequence analysis revealed the close relation of the isolated ancient bacteria to the modern bacteria of this species. Moreover, several genes associated with resistance to different groups of antibiotics were found in the S. hominis MMP2 genome. Conclusions: These findings supports a hypothesis that antibiotic resistance has an ancient origin. The enrichment of cultivated bacterial communities with ancient permafrost strains is essential for the analysis of bacterial evolution and antibiotic resistance.
Background: Biogenic amines (BAs) are metabolites produced by the decarboxylation of amino acids with significant physiological functions in eukaryotic and prokaryotic cells. BAs can be produced by bacteria in fermented foods, but little is known concerning the potential for microbes within the human gut microbiota to produce or degrade BAs. Objective: To isolate and identify BA-producing and BA-degrading microbes from the human gastrointestinal tract. Design: Fecal samples from human volunteers were screened on multiple growth media, under multiple growth conditions. Bacterial species were identified using 16S rRNA sequencing and BA production or degradation was assessed using ultra-performance liquid chromatography. Results: In total, 74 BA-producing or BA-degrading strains were isolated from the human gut. These isolates belong to the genera Bifidobacterium, Clostridium, Enterococcus, Lactobacillus, Pediococcus, Streptococcus, Enterobacter, Escherichia, Klebsiella, Morganella and Proteus. While differences in production or degradation of specific BAs were observed at the strain level, our results suggest that these metabolic activities are widely spread across different taxa present within the human gut microbiota. Conclusions: The isolation and identification of microbes from the human gut with BA-producing and BA-degrading metabolic activity is an important first step in developing a better understanding of how these metabolites influence health and disease.
Background: The intestinal microbiota, through complex interactions with the gut mucosa, play a key role in the pathogenesis of colon carcinoma and inflammatory bowel disease (IBD). The disease condition and dietary habits both influence gut microbial diversity.Objective: The aim of this study was to assess the gut microbial profile of healthy subjects and patients with colon carcinoma and IBD. Healthy subjects included 'Indian vegetarians/lactovegetarians', who eat plant produce, milk and milk products, and 'Indian non-vegetarians', who eat plant produce, milk and milk products, certain meats and fish, and the eggs of certain birds and fish. 'Indian vegetarians' are different from 'vegans', who do not eat any foods derived wholly or partly from animals, including milk products.Design: Stool samples were collected from healthy Indian vegetarians/lactovegetarians and non-vegetarians, and colon cancer and IBD patients. Clonal libraries of 16S ribosomal DNA (rDNA) of bacteria were created from each sample. Clones were sequenced from one representative sample of each group. Approximately 500 white colonies were picked at random from each sample and 100 colonies were sequenced after amplified rDNA restriction analysis.Results: The dominant phylum from the healthy vegetarian was Firmicutes (34%), followed by Bacteroidetes (15%). The balance was reversed in the healthy non-vegetarian (Bacteroidetes 84%, Firmicutes 4%; ratio 21:1). The colon cancer and IBD patients had higher percentages of Bacteroidetes (55% in both) than Firmicutes (26% and 12%, respectively) but lower Bacteroidetes:Firmicutes ratios (3.8:1 and 2.4:1, respectively) than the healthy non-vegetarian. Bacterial phyla of Verrucomicrobiota and Actinobacteria were detected in 23% and 5% of IBD and colon patients, respectively.Conclusions: Ribosomal Database Project profiling of gut flora in this study population showed remarkable differences, with unique diversity attributed to different diets and disease conditions.
