Rectal swabs as a viable alternative to faecal sampling for the analysis of gut microbiota functionality and composition.

Faecal or biopsy samples are frequently used to analyse the gut microbiota, but issues remain with the provision and collection of such samples. Rectal swabs are widely-utilised in clinical practice and previous data demonstrate their potential role in microbiota analyses; however, studies to date have been heterogenous, and there are a particular lack of data concerning the utility of swabs for the analysis of the microbiota's functionality and metabolome. We compared paired stool and rectal swab samples from healthy individuals to investigate whether rectal swabs are a reliable proxy for faecal sampling. There were no significant differences in key alpha and beta diversity measures between swab and faecal samples, and inter-subject variability was preserved. Additionally, no significant differences were demonstrated in abundance of major annotated phyla. Inferred gut functionality using Tax4Fun2 showed excellent correlation between the two sampling techniques (Pearson's coefficient r = 0.9217, P < 0.0001). Proton nuclear magnetic resonance (1H NMR) spectroscopy enabled the detection of 20 metabolites, with overall excellent correlation identified between rectal swab and faecal samples for levels all metabolites collectively, although more variable degrees of association between swab and stool for levels of individual metabolites. These data support the utility of rectal swabs in both compositional and functional analyses of the gut microbiota.

Comparative effectiveness of a second-line biologic in patients with ulcerative colitis: vedolizumab followed by an anti-TNF versus anti-TNF followed by vedolizumab.

Background: Sequential drug treatment with biological agents in ulcerative colitis (UC) is becoming increasingly complex. There are few studies comparing head-to-head outcomes in second-line treatments. The study assesses whether using anti-tumour necrosis factor (anti-TNF)-α therapy following the α4ß7 integrin blocker vedolizumab (VDZ) or VDZ after an anti-TNF has more favourable clinical outcomes in UC in a real-world outpatient setting. Methods: Patients with UC who were exposed to first-line anti-TNF (adalimumab or infliximab) or VDZ who subsequently switched to the alternate class between May 2013 and August 2020 were identified by reviewing patient databases at 10 hospitals. Data were collected retrospectively using patient records. Baseline demographics, disease activity indices, biochemical markers, endoscopic Mayo score, colectomy rates, treatment persistence and urgent hospital utilisation composite endpoint (UHUC) rates were examined over a 52-week period. Results: Second-line week 52 treatment persistence was higher in the VDZ group (71/81, 89%) versus the anti-TNF group (15/34, 44%; p=0.0001), as were week 52 colectomy-free survival (VDZ: 77/80, 96%, vs anti-TNF: 26/32, 81%; p=0.009), week 52 UHUC survival (VDZ: 68/84, 81%, vs anti-TNF: 20/34, 59%; p=0.002) and week 52 corticosteroid-free clinical remission (CFCR) rates (VDZ: 22/34, 65%, vs anti-TNF: 4/20, 20%; p=0.001). Conclusion: Compared with second-line anti TNF usage, the VDZ second-line cohort had significantly higher 52-week treatment persistence, UHUC survival, higher colectomy-free survival rates and higher week 52 CFCR. These data suggest that VDZ is an effective biologic in UC as a second-line therapy after anti-TNF exposure. It highlights the effect of biological order on clinically important outcomes.

Improved quantitation of short-chain carboxylic acids in human biofluids using 3-nitrophenylhydrazine derivatization and liquid chromatography with tandem mass spectrometry (LC-MS/MS).

Short-chain carboxylic acids (SCCAs) produced by gut microbial fermentation may reflect gastrointestinal health. Their concentrations in serum and urine are indicative of specific metabolic pathway activity; therefore, accurate quantitation of SCCAs in different biofluids is desirable. However, it is often challenging to quantitate SCCAs since matrix effects, induced by the presence of a vast variety of other compounds other than SCCAs in complex biofluids, can suppress or enhance signals. Materials used for sample preparation may introduce further analytical challenges. This study reports for the first time a LC-MS/MS-based method to quantitate ten SCCAs (lactate, acetate, 2-hydroxybutyrate, propionate, isobutyrate, butyrate, 2-methylbutyrate, isovalerate, valerate and hexanoate) and evaluates the matrix effects in five human biofluids: serum, urine, stool, and contents from the duodenum and intestinal stoma bags. The optimized method, using 3-Nitrophenylhydrazone as a derivatization agent and a Charge Surface Hybrid reverse phase column, showed clear separation for all SCCAs at a concentration range of 0.1-100 µM, in a 10.5 min run without carry-over effects. The validation of the method showed a good linearity (R2 > 0.99), repeatability (CV ≤ 15%) assessed by intra- and inter-day monitoring. The lowest limit of detection (LLOD) was 25 nM and lowest limit of quantitation (LLOQ) was 50 nM for nine SCCA except acetate at 0.5 and 1 µM, respectively. Quantitative accuracy in all biofluids for most compounds was < ±15%. In summary, this methodology has the advantages over other techniques for its simple and fast sample preparation and a high level of selectivity, repeatability and robustness for SCCA quantification. It also reduced interferences from the matrix or sample containers, making it ideal for use in high-throughput analyses of biofluid samples from large-scale studies.

Systematic review: the association between the gut microbiota and medical therapies in inflammatory bowel disease.

BACKGROUND: The gut microbiota has been implicated in the pathogenesis of inflammatory bowel disease (IBD), with Faecalibacterium prausnitizii associated with protection, and certain genera (including Shigella and Escherichia) associated with adverse features. The variability of patient response to medical therapies in IBD is incompletely understood. Given the recognised contribution of the microbiota to treatment efficacy in other conditions, there may be interplay between the gut microbiota, IBD medical therapy and IBD phenotype. AIMS: To evaluate the bidirectional relationship between IBD medical therapies and the gut microbiota. METHODS: We conducted a systematic search of MEDLINE and EMBASE. All original studies analysing interactions between the gut microbiota and established IBD medical therapies were included. RESULTS: We screened 1296 records; 19 studies were eligible. There was heterogeneity in terms of sample analysis, treatment protocols, and outcome reporting. Increased baseline α-diversity was observed in responders versus non-responders treated with exclusive enteral nutrition (EEN), infliximab, ustekinumab or vedolizumab. Higher baseline Faecalibacterium predicted response to infliximab and ustekinumab. A post-treatment increase in Faecalibacterium prausnitzii was noted in responders to aminosalicylates, anti-TNF medications and ustekinumab; conversely, this species decreased in responders to EEN. Escherichia was a consistent marker of unfavourable drug response, and its presence in the gut mucosa correlated with inflammation in aminosalicylate-treated patients. CONCLUSIONS: Both gut microbiota diversity and specific taxonomic features (including high abundance of Faecalibacterium) are associated with the efficacy of a range of IBD therapies. These findings hold promise for a potential role for the gut microbiota in explaining the heterogeneity of patient response to IBD treatments.

Grass-roots junior doctor communication network in response to the COVID-19 pandemic: a service evaluation.

BACKGROUND: COVID-19 was declared a worldwide pandemic on 11 March 2020. Imperial College Healthcare NHS Trust provides 1412 inpatient beds staffed by 1200 junior doctors and faced a large burden of COVID-19 admissions. LOCAL PROBLEM: A survey of doctors revealed only 20% felt confident that they would know to whom they could raise concerns and that most were getting information from a combination of informal work discussions, trust emails, social media and medical literature. METHODS: This quality improvement project was undertaken aligning with Standards for Quality Improvement Reporting Excellence 2.0 guidelines. Through an iterative process, a digital network (Imperial Covid cOmmunications Network; ICON) using existing smartphone technologies was developed. Concerns were collated from the junior body and conveyed to the leadership team (vertical-bottom-up using Google Form) and responses were conveyed from leadership to the junior body (vertical-top-down using WhatsApp and Zoom). Quantitative analysis on engagement with the network (members of the group and number of issues raised) and qualitative assessment (thematic analysis on issues) were undertaken. RESULTS: Membership of the ICON WhatsApp group peaked at 780 on 17 May 2020. 197 concerns were recorded via the Google Form system between 20 March and 14 June 2020. There were five overarching themes: organisational and logistics; clinical strategy concerns; staff safety and well-being; clinical (COVID-19) and patient care; and facilities. 94.4% of members agreed ICON was helpful in receiving updates and 88.9% agreed ICON improved collaboration. CONCLUSIONS: This work demonstrates that a coordinated network using existing smartphone technologies and a novel communications structure can improve collaboration between senior leadership and junior doctors. Such a network could play an important role during times of pressure in a healthcare system.

Faecal neutrophil elastase-antiprotease balance reflects colitis severity.

Given the global burden of diarrheal diseases on healthcare it is surprising how little is known about the drivers of disease severity. Colitis caused by infection and inflammatory bowel disease (IBD) is characterised by neutrophil infiltration into the intestinal mucosa and yet our understanding of neutrophil responses during colitis is incomplete. Using infectious (Citrobacter rodentium) and chemical (dextran sulphate sodium; DSS) murine colitis models, as well as human IBD samples, we find that faecal neutrophil elastase (NE) activity reflects disease severity. During C. rodentium infection intestinal epithelial cells secrete the serine protease inhibitor SerpinA3N to inhibit and mitigate tissue damage caused by extracellular NE. Mice suffering from severe infection produce insufficient SerpinA3N to control excessive NE activity. This activity contributes to colitis severity as infection of these mice with a recombinant C. rodentium strain producing and secreting SerpinA3N reduces tissue damage. Thus, uncontrolled luminal NE activity is involved in severe colitis. Taken together, our findings suggest that NE activity could be a useful faecal biomarker for assessing disease severity as well as therapeutic target for both infectious and chronic inflammatory colitis.

Mesalazine-induced myocarditis: a case report.

BACKGROUND: Myocarditis is a rare complication of therapy with mesalazine, a drug widely prescribed in the treatment of inflammatory bowel disease. CASE PRESENTATION: We report a case of myocarditis occurring in a 49-year-old British man 10 days following initiation of mesalazine therapy for treatment of ulcerative colitis. He presented with troponin-positive chest pain, and the diagnosis of myocarditis was confirmed on the basis of cardiac magnetic resonance imaging, which showed subepicardial delayed gadolinium enhancement in the basal to middle inferior and inferolateral segments of the heart. The patient's symptoms and condition improved upon stopping mesalazine, and he made a full recovery. CONCLUSIONS: Mesalazine-induced myocarditis may be more common than first appreciated and is potentially fatal. Therefore, it is imperative that clinicians be aware of this potentially life-threatening adverse effect of mesalazine therapy and warn patients to seek urgent medical attention if cardiac symptoms arise.

Beyond weight loss: evaluating the multiple benefits of bariatric surgery after Roux-en-Y gastric bypass and adjustable gastric band.

BACKGROUND: Despite the evidence for benefits beyond weight loss following bariatric surgery, assessments of surgical outcomes are often limited to changes in weight and remission of type 2 diabetes mellitus. To address this shortfall in assessment, the King's Obesity Staging System was developed. This system evaluates the individual in severity stages of physical, psychological, socio-economic and functional disease. These are categorised into disease domains arranged so as to allow an alphabetic mnemonic as Airways, Body Mass Index (BMI), Cardiovascular, Diabetes, Economic, Functional, Gonadal, Health Status (perceived) and (body) Image. METHODS: In this cohort study, patients were assessed before and 12 months after surgery using the modified King's Obesity Staging Score. We studied 217 consecutive patients undergoing Roux-en-Y gastric bypass (RYGB; N = 148) and laparoscopic adjustable gastric band (LAGB; N = 69) using the modified King's Obesity Staging System to determine health benefits after bariatric surgery. RESULTS: Preoperatively, the groups had similar BMI, but the RYGB group had worse Airways, Cardiovascular, and Diabetes scores (p < 0.05). After surgery, RYGB and LAGB produced improvements in all scores. In a subgroup paired analysis matched for preoperative Airways, BMI, Cardiovascular, and Diabetes scores, both procedures showed similar improvements in all scores, except for BMI where RYGB had a greater reduction than LAGB (p < 0.05). CONCLUSIONS: Both RYGB and LAGB deliver multiple benefits to patients as evaluated by the modified King's Obesity Staging System beyond BMI and glycaemic markers. A validated staging score such as the modified King's Obesity Staging System can be used to quantify these benefits.