Within the framework of the β-hemolytic streptococci surveillance carried out by the National Reference Laboratory from Uruguay, three putative Streptococcus equi subsp. zooepidemicus (SEZ) were ...received from different health centers. Being these the first reports associated with human infections in Uruguay, the objective of this work was to confirm their identification, to determine their genetic relationship and to study their antibiotic susceptibility. Using four different methods, they were identified as SEZ, a subspecies which has been described as the etiologic agent of rare and severe zoonosis in a few cases in other countries. The three isolates presented different pulsotypes by PFGE; however, two of them appeared to be related and were confirmed as ST431 by MLST, while the remaining isolate displayed ST72. Their resistance profile exhibited an unexpected feature: despite all of them were susceptible to macrolides, they showed different levels of resistance to clindamycin, i.e. they had the so-called "L phenotype". This rare trait is known to be due to a nucleotidyl-transferase, encoded by genes of the lnu family. Although this phenotype was previously described in a few SEZ isolates, its genetic basis has not been studied yet. This was now analyzed by PCR in the three isolates and they were found to contain a lnuB gene. The lnuB sequence was identical among the three isolates and with many lnuB sequences deposited in data banks. In conclusion, for the first time in Uruguay, three SEZ isolates recovered from non-epidemiologically related cases of human invasive infection were identified. Moreover, this is the first report about the presence of a lnu gene in the S. equi species, revealing the active lateral spread of the lnuB in a new streptococcal host.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background
Short‐chain fructooligosaccharides (scFOS) have beneficial effects in subjects with minor digestive complaints, but the potential mechanisms involved have not been elucidated. The aim of ...the study was to evaluate changes in rectal sensitivity related to the clinical effects of scFOS in a selected group of patients with irritable bowel syndrome (IBS) and rectal hypersensitivity.
Methods
In 79 IBS patients (defined by Rome III criteria) with rectal hypersensitivity (defined as discomfort threshold ≤44 g) a parallel, placebo‐controlled, randomized, and double‐blind study was performed to assess the effects of dietary supplementation (5 g d−1) with scFOS vs placebo for 4 weeks on rectal sensitivity (primary outcome: tolerance to increasing wall tension applied by a tensostat), clinical outcomes (IBS, anxiety/depression and quality of life scores) and composition of fecal microbiota.
Key Results
Rectal discomfort threshold, and IBS and quality of life scores, significantly improved during treatment, but in a similar manner in both scFOS and placebo groups; a post‐hoc analysis showed that the effect of scFOS on rectal sensitivity was more pronounced in constipation‐predominant‐IBS patients (P=.051 vs placebo). Contrary with placebo, scFOS significantly reduced anxiety scores and increased fecal Bifidobacteria (P<.05 for both) without modifying other bacterial groups.
Conclusions & Interfences
The effect of scFOS on anxiety may be related to modulation of the gut microbiota; demonstration of effects of scFOS on rectal sensitivity may require higher doses and may depend on the IBS subgroup.
Our aim was to evaluate the effects of short‐chain fructooligosaccharides (scFOS) on rectal sensitivity, fecal microbiota, and symptoms in patients with irritable bowel syndrome. Rectal sensitivity improved with scFOS and placebo alike; however, scFOS, but not placebo, significantly increased fecal Bifidobacteria and reduced anxiety score.
General introduction The concept of visceral hypersensitivity is accepted as being germane to several functional gastrointestinal disorders (FGIDs). The causes or risk factors associated with this ...hypersensitivity are unclear. This article addresses the proposed mechanisms leading to hypersensitivity: from genetic to inflammatory disorders, from central to peripheral alterations of function. However, in order to place visceral hypersensitivity in a more global perspective as an aetiological factor for FGIDs, it also provides a review of recent evidence regarding the role of other peripheral mechanisms (the intraluminal milieu), as also genetic factors in the pathophysiology of these disorders. The article has been divided into five independent sections. The first three sections summarize the evidence of visceral hypersensitivity as a biological marker of functional gut disorders, the peripheral and central mechanisms involved, and the role of inflammation on hypersensitivity. In opposition to visceral hypersensitivity as an isolated phenomenon in functional gut disorders, the last two sections focus on the importance of peripheral mechanisms, like motor disturbances, specifically those resulting on altered transport of intestinal gas, and alterations of the intraluminal milieu and genetics.
Background
The biological response to a meal includes physiological changes, primarily related to the digestive process, and a sensory experience, involving sensations related to the homeostatic ...control of food consumption, eg, satiety and fullness, with a hedonic dimension, ie associated with changes in digestive well‐being and mood. The responses to a meal include a series of events before, during and after ingestion. While much attention has been paid to the events before and during ingestion, relatively little is known about the postprandial sensations, which are key to the gastronomical experience.
Purpose
The aim of this narrative review is to provide a comprehensive overview and to define the framework to investigate the factors that determine the postprandial experience. Based on a series of proof‐of‐concept studies and related information, we propose that the biological responses to a meal depend on the characteristics of the meal, primarily its palatability and composition, and the responsiveness of the guest, which may be influenced by multiple previous and concurrent conditioning factors. This information provides the scientific backbone to the development of personalized gastronomy.
Factors that determine the postprandial experience. The biological response to meal ingestion involves physiological changes, eg, the digestive process, and a sensory experience including homeostatic sensations (satiety, fullness) with a hedonic dimension (digestive well‐being, mood), ie, the postprandial experience. The normal postprandial experience depends on the characteristics of the meal and the responsiveness of the eater, which may be influenced by multiple previous and concurrent conditioning factors.
Summary
Background
Prebiotics have been shown to reduce abdominal symptoms in patients with functional gut disorders, despite that they are fermented by colonic bacteria and may induce gas‐related ...symptoms.
Aim
To investigate changes in the metabolic activity of gut microbiota induced by a recognised prebiotic.
Methods
Healthy subjects (n = 20) were given a prebiotic (2.8 g/day HOST‐G904, HOST Therabiomics, Jersey, Channel Islands) for 3 weeks. During 3‐day periods immediately before, at the beginning and at the end of the administration subjects were put on a standard diet (low fibre diet supplemented with one portion of high fibre foods) and the following outcomes were measured: (i) number of daytime gas evacuations for 2 days by means of an event marker; (ii) volume of gas evacuated via a rectal tube during 4 h after a test meal; and (iii) microbiota composition by faecal Illumina MiSeq sequencing.
Results
At the beginning of administration, HOST‐G904 significantly increased the number of daily anal gas evacuations (18 ± 2 vs. 12 ± 1 pre‐administration; P < 0.001) and the volume of gas evacuated after the test meal (236 ± 23 mL vs. 160 ± 17 mL pre‐administration; P = 0.006). However, after 3 weeks of administration, these effects diminished (11 ± 2 daily evacuations, 169 ± 23 mL gas evacuation). At day 21, relative abundance of butyrate producers (Lachnospiraceae) correlated inversely with the volume of gas evacuated (r = −0.52; P = 0.02).
Conclusion
The availability of substrates induces an adaptation of the colonic microbiota activity in bacterial metabolism, which produces less gas and associated issues. Clinical trials.gov NCT02618239.
Linked ContentThis article is linked to Staudacher paper. To view this article visit https://doi.org/10.1111/apt.13976.
Genomic islands are DNA regions containing variable genetic information related to secondary metabolism. Frequently, they have the ability to excise from and integrate into replicons through ...site-specific recombination. Thus, they are usually flanked by short direct repeats that act as attachment sites, and contain genes for an integrase and an excisionase which carry out the genetic exchange. These mobility events would be at the basis of the horizontal transfer of genomic islands among bacteria.Microcin H47 is a ribosomally-synthesized antibacterial peptide that belongs to the group of chromosome-encoded microcins. The 13 kb-genetic system responsible for its production resides in the chromosome of the Escherichia coli H47 strain and is flanked by extensive and imperfect direct repeats. In this work, both excision and integration of the microcin H47 system were experimentally detected. The analyses were mainly performed in E. coli K12 cells carrying the microcin system cloned in a multicopy plasmid. As expected of a site-specific recombination event, the genetic exchange also occurred in a context deficient for homologous recombination. The DNA sequence of the attachment sites resulting from excision were hybrid between the sequences of the direct repeats. Unexpectedly, different hybrid attachment sites appeared which resulted from recombination in four segments of identity between the direct repeats. Genes encoding the trans-acting proteins responsible for the site-specific recombination were shown to be absent in the microcin H47 system. Therefore, they should be provided by the remaining genetic context, not only in the H47 strain but also in E. coli K12 cells, where both excision and integration occurred. Moreover, a survey of the attachment sites in data banks revealed that they are widely spread among E. coli strains. It is concluded that the microcin system is a small island -H47 genomic island- that would employ a parasitic strategy for its mobility.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Class 1 integrons (Int1) contribute to antibiotic multiresistance in Gram-negative bacteria. Being frequently carried by conjugative plasmids, their spread would depend to some extent on their ...horizontal transfer to other bacteria. This was the main issue that was addressed in this work: the analysis of Int1 lateral transfer in the presence of different antibiotic pressures. Strains from a previously obtained collection of Escherichia coli K12 carrying natural Int1+ conjugative plasmids were employed as Int1 donors in conjugation experiments. Two recipient strains were used: an E. coli K12 and an uropathogenic E. coli isolate. The four antibiotics employed to select transconjugants in LB solid medium were ampicillin, trimethoprim, sulfamethoxazole, and co-trimoxazole. For this purpose, adequate final concentrations of the three last antibiotics had to be determined. Abundant transconjugants resulted from the mating experiments and appeared in most -but not all-selective plates. In those supplemented with sulfamethoxazole or co-trimoxazole, transconjugants grew or not depending on the genetic context of the recipient strain and on the type of gene conferring sulfonamide resistance (sul1 or sul2) carried by the Int1+ plasmid. The horizontal transfer of a recombinant plasmid bearing an Int1 was also assayed by transformation and these experiments provided further information on the viability of the Int1+ clones. Overall, results point to the existence of constraints for the lateral transfer of Int1 among E. coli bacteria, which are particularly evidenced under the antibiotic pressure of sulfamethoxazole or of its combined formula co-trimoxazole.
•The lateral transfer of class 1 integrons among Escherichia coli strains was assayed.•The success of Int1 transfer depends on the genetic context of the recipient strain.•The success of Int1 transfer depends on the antibiotic pressure used for selection.•The type of sul gene determines the level of sulfonamide resistance in E. coli K12.•Sulfonamide affects the viability of Int1+E. coli K12 transconjugants with only sul1.
Summary
Background
Intestinal immune activation is involved in irritable bowel syndrome (IBS) pathophysiology. While most dietary approaches in IBS involve food avoidance, there are fewer indications ...on food supplementation. Palmithoylethanolamide, structurally related to the endocannabinoid anandamide, and polydatin are dietary compounds which act synergistically to reduce mast cell activation.
Aim
To assess the effect on mast cell count and the efficacy of palmithoylethanolamide/polydatin in patients with IBS.
Methods
We conducted a pilot, 12‐week, randomised, double‐blind, placebo‐controlled, multicentre study assessing the effect of palmithoylethanolamide/polydatin 200 mg/20 mg or placebo b.d. on low‐grade immune activation, endocannabinoid system and symptoms in IBS patients. Biopsy samples, obtained at screening visit and at the end of the study, were analysed by immunohistochemistry, enzyme‐linked immunoassay, liquid chromatography and Western blot.
Results
A total of 54 patients with IBS and 12 healthy controls were enrolled from five European centres. Compared with controls, IBS patients showed higher mucosal mast cell counts (3.2 ± 1.3 vs. 5.3 ± 2.7%, P = 0.013), reduced fatty acid amide oleoylethanolamide (12.7 ± 9.8 vs. 45.8 ± 55.6 pmol/mg, P = 0.002) and increased expression of cannabinoid receptor 2 (0.7 ± 0.1 vs. 1.0 ± 0.8, P = 0.012). The treatment did not significantly modify IBS biological profile, including mast cell count. Compared with placebo, palmithoylethanolamide/polydatin markedly improved abdominal pain severity (P < 0.05).
Conclusions
The marked effect of the dietary supplement palmithoylethanolamide/polydatin on abdominal pain in patients with IBS suggests that this is a promising natural approach for pain management in this condition. Further studies are now required to elucidate the mechanism of action of palmithoylethanolamide/polydatin in IBS. ClinicalTrials.gov number, NCT01370720.
Linked ContentThis article is linked to Quigley paper. To view this article visit https://doi.org/10.1111/apt.14014.
Patients with functional gut disorders, irritable bowel disease, and related syndromes frequently attribute their symptoms to intestinal gas. While patients are usually convinced of their ...interpretation, the doctor has few arguments to confirm or refute it, and in this context intestinal gas has become a myth. Studies of intestinal gas dynamics have demonstrated subtle dysfunctions in intestinal motility. Hopefully, extension of these studies may help both in the classification of patients complaining of gas symptoms based on pathophysiological mechanisms, and in identification of objective markers to test mechanistically oriented treatment options.
Background
We have shown that a galactooligosaccharide prebiotic administration (HOST‐G904) initially increased intestinal gas production and this increase declined back to baseline after 2 week ...administration. Our aim was to determine the mechanism of microbiota adaptation; i.e., to determine whether the net reduction is due to decreased overall production or increased gas consumption.
Methods
In 10 healthy subjects, intestinal gas production and intraluminal disposal was measured before, at the beginning and after 2 week of HOST‐G904 prebiotic administration. Anal gas was collected for 4 hour after a probe meal. Paired studies were performed without and with high‐rate infusion of exogenous gas (24 mL/min) into the jejunum to wash‐out the endogenous gas produced by bacterial fermentation. The exogenous gas infused was labeled (5% SF6) to calculate the proportion of endogenous gas evacuated.
Key Results
The volume of intestinal gas produced i.e., endogenous gas washed‐out, increased by 37% at the beginning of HOST‐G904 administration (P=.049 vs preadministration) and decreased down to preadministration level after 2 week administration (P=.030 vs early administration). The proportion of gas eliminated from the lumen before reaching the anus tended to increase after 2‐week administration (87±3% vs 78±5% preadministration; P=.098).
Conclusions & Inferences
Adaptation to regular consumption of HOST‐G904 prebiotic involves a shift in microbiota metabolism toward low‐gas producing pathways, with a non‐significant increase in gas‐consuming activity. Hence, regular consumption of HOST‐G904 regulates intestinal gas metabolism: less gas is produced and a somewhat larger proportion of it is consumed.
Effect of HOST‐G904 administration on the volume of gas evacuated. Anal evacuation of endogenous gas (produced by bacterial fermentation) 2‐4 hours after a probe meal with and without gaseous wash‐out measured before, at the beginning and after 2 week administration (n=10). With gaseous wash‐out, most endogenous gas produced by colonic fermentation was flushed out and evacuated per anus: gas production increased in the early administration phase and returned back to baseline. Without wash‐out, a large proportion of the gas produced by bacterial fermentation was eliminated from the lumen before reaching the anus and the proportion tended to increase during HOST‐G904 administration.
View the podcast on this paper at the following sites: iTunes: https://itunes.apple.com/gb/podcast/neurogastroenterology-motility-september-2017/id1257018975 Youtube: https://youtu.be/YDdDPaSnzuc
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