Antibiotics promote inflammation through the translocation of native commensal colonic bacteria

Antibiotics damage the colonic mucus barrier in a microbiota-independent manner

Antibiotic use is a risk factor for development of inflammatory bowel diseases (IBDs). IBDs are characterized by a damaged mucus layer, which does not separate the intestinal epithelium from the microbiota. Here, we hypothesized that antibiotics affect the integrity of the mucus barrier, which allows bacterial penetrance and predisposes to intestinal inflammation. We found that antibiotic treatment led to breakdown of the colonic mucus barrier and penetration of bacteria into the mucus layer. Using fecal microbiota transplant, RNA sequencing followed by machine learning, ex vivo mucus secretion measurements, and antibiotic treatment of germ-free mice, we determined that antibiotics induce endoplasmic reticulum stress in the colon that inhibits colonic mucus secretion in a microbiota-independent manner. This antibiotic-induced mucus secretion flaw led to penetration of bacteria into the colonic mucus layer, translocation of microbial antigens into circulation, and exacerbation of ulcerations in a mouse model of IBD. Thus, antibiotic use might predispose to intestinal inflammation by impeding mucus production.

Biosafety assessment of laying hens fed different treatments of black soldier flies (Hermetia illucens) under doxycycline stress

The black soldier fly (BSF, Hermetia illucens) is a resource insect that can utilize livestock and poultry feces. However, BSFs may also increase the risk of transmission of antibiotic resistance genes (AGRs) that are widespread in livestock and poultry farm environments. Therefore, we aimed to evaluate the biosecurity risks of different BSF treatments in the laying chicken food chain using the "chicken manure-BSF-laying hens" model. Our results indicated that different BSF treatments significantly affected antibiotic residue, ARGs, MGEs, bacterial antibiotic resistance, and bacterial microbial community composition in the food chain of laying hens fed BSFs. These risks can be effectively reduced through starvation treatment and high-temperature grinding treatment. Comprehensive risk assessment analysis revealed that starvation combined with high-temperature milling (Group H) had the greatest effect.

Effects of dietary supplementation of cobiotic based on Agave fructans on growth performance, blood parameters, oxidative damage and immune status of broiler

This study evaluated the effect of cobiotic (CO) composed of organic fructans powder of Agave tequilana and turmeric powder of Curcuma longa L. as an alternative of antibiotic growth promoters (AGPs) on growth performance, blood parameters, intestinal pH, oxidative stress, and cytokines serum levels of broiler chickens. A total of 135 one-day-old Ross 308 broilers distributed to five experimental groups, which included starter or finisher standard diets without AGPs (CON), CON + 0.25 COLI-ZIN g/kg feed (AGP), CON + 0.1 g Agave fructans/kg feed (AF), CON + 0.5 g turmeric powder/kg feed (TP) and CON + 0.1 g AF + 0.5 g TP /kg feed (CO), for 49 days. AF followed by TP, decreased feed intake, obtaining the best FCR. AGP increased the heterophil-lymphocyte ratio compared to other groups. CO significantly decreased the pH of the cecal content. AF increased IL-10 levels, while TP decreased it. AF decreased the IL-1β levels. The present study showed that including a cobiotic based on AF and TP or components separately in a broilers diet improved growth performance, modified intestinal and cecum pH, and stimulated the immune system, which suggests CO as a safe alternative to AGP.

Fermented Milk Containing Lacticaseibacillus rhamnosus SNU50430 Modulates Immune Responses and Gut Microbiota in Antibiotic-Treated Mice

Antibiotics are used to control infectious diseases. However, adverse effects of antibiotics, such as devastation of the gut microbiota and enhancement of the inflammatory response, have been reported. Health benefits of fermented milk are established and can be enhanced by the addition of probiotic strains. In this study, we evaluated effects of fermented milk containing Lacticaseibacillus rhamnosus (L. rhamnosus) SNUG50430 in a mouse model with antibiotic treatment. Fermented milk containing 2 × 105 colony-forming units of L. rhamnosus SNUG50430 was administered to six week-old female BALB/c mice for 1 week. Interleukin (IL)-10 levels in colon samples were significantly increased (P < 0.05) compared to water-treated mice, whereas interferon-gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) were decreased, of mice treated with fermented milk containing L. rhamnosus SNUG50430-antibiotics-treated (FM+LR+Abx-treated) mice. Phylum Firmicutes composition in the gut was restored and the relative abundances of several bacteria, including the genera Coprococcus and Lactobacillus, were increased in FM+LR+Abx-treated mice compared to PBS+Abx-treated mice. Interestingly, abundances of genus Coprococcus and Lactobacillus were positively correlated with IL-5 and IL-10 levels (P < 0.05) in colon samples and negative correlated with IFN-γ and TNF-α levels in serum samples (P < 0.001). Acetate and butyrate were increased in mice with fermented milk and fecal microbiota of FM+LR+Abx-treated mice were highly enriched with butyrate metabolism pathway compared to water-treated mice (P < 0.05). Thus, fermented milk containing L. rhamnosus SNUG50430 was shown to ameliorate adverse health effects caused by antibiotics through modulating immune responses and the gut microbiota.

Gut microbes improve prognosis of Klebsiella pneumoniae pulmonary infection through the lung-gut axis

Background

The gut microbiota plays a vital role in the development of sepsis and in protecting against pneumonia. Previous studies have demonstrated the existence of the gut-lung axis and the interaction between the gut and the lung, which is related to the prognosis of critically ill patients; however, most of these studies focused on chronic lung diseases and influenza virus infections. The purpose of this study was to investigate the effect of faecal microbiota transplantation (FMT) on Klebsiella pneumoniae-related pulmonary infection via the gut-lung axis and to compare the effects of FMT with those of traditional antibiotics to identify new therapeutic strategies.

Methods

We divided the mice into six groups: the blank control (PBS), pneumonia-derived sepsis (KP), pneumonia-derived sepsis + antibiotic (KP + PIP), pneumonia-derived sepsis + faecal microbiota transplantation(KP + FMT), antibiotic treatment control (KP+PIP+PBS), and pneumonia-derived sepsis+ antibiotic + faecal microbiota transplantation (KP + PIP + FMT) groups to compare the survival of mice, lung injury, inflammation response, airway barrier function and the intestinal flora, metabolites and drug resistance genes in each group.

Results

Alterations in specific intestinal flora can occur in the gut of patients with pneumonia-derived sepsis caused by Klebsiella pneumoniae. Compared with those in the faecal microbiota transplantation group, the antibiotic treatment group had lower levels of proinflammatory factors and higher levels of anti-inflammatory factors but less amelioration of lung pathology and improvement of airway epithelial barrier function. Additionally, the increase in opportunistic pathogens and drug resistance-related genes in the gut of mice was accompanied by decreased production of favourable fatty acids such as acetic acid, propionic acid, butyric acid, decanoic acid, and secondary bile acids such as chenodeoxycholic acid 3-sulfate, isodeoxycholic acid, taurodeoxycholic acid, and 3-dehydrocholic acid; the levels of these metabolites were restored by faecal microbiota transplantation. Faecal microbiota transplantation after antibiotic treatment can gradually ameliorate gut microbiota disorder caused by antibiotic treatment and reduce the number of drug resistance genes induced by antibiotics.

Conclusion

In contrast to direct antibiotic treatment, faecal microbiota transplantation improves the prognosis of mice with pneumonia-derived sepsis caused by Klebsiella pneumoniae by improving the structure of the intestinal flora and increasing the level of beneficial metabolites, fatty acids and secondary bile acids, thereby reducing systemic inflammation, repairing the barrier function of alveolar epithelial cells, and alleviating pathological damage to the lungs. The combination of antibiotics with faecal microbiota transplantation significantly alleviates intestinal microbiota disorder, reduces the selection for drug resistance genes caused by antibiotics, and mitigates lung lesions; these effects are superior to those following antibiotic monotherapy.

CCR2-dependent CX3CR1+ colonic macrophages promote Enterococcus faecalis dissemination

Enterococci are common commensal bacteria that colonize the gastrointestinal tracts of most mammals, including humans. Importantly, these bacteria are one of the leading causes of nosocomial infections. This study examined the role of colonic macrophages in facilitating Enterococcus faecalis infections in mice. We determined that depletion of colonic phagocytes resulted in the reduction of E. faecalis dissemination to the gut-draining mesenteric lymph nodes. Furthermore, we established that trafficking of monocyte-derived CX3CR1-expressing macrophages contributed to E. faecalis dissemination in a manner that was not reliant on CCR7, the conventional receptor involved in lymphatic migration. Finally, we showed that E. faecalis mutants with impaired intracellular survival exhibited reduced dissemination, suggesting that E. faecalis can exploit host immune cell migration to disseminate systemically and cause disease. Our findings indicate that modulation of macrophage trafficking in the context of antibiotic therapy could serve as a novel approach for preventing or treating opportunistic infections by disseminating enteric pathobionts like E. faecalis.

Infection and antibiotic-associated changes in the fecal microbiota of C. rodentium ϕstx2dact-infected C57BL/6 mice

Enterohemorrhagic Escherichia coli causes watery to bloody diarrhea, which may progress to hemorrhagic colitis and hemolytic-uremic syndrome. While early studies suggested that antibiotic treatment may worsen the pathology of an enterohemorrhagic Escherichia coli (EHEC) infection, recent work has shown that certain non-Shiga toxin-inducing antibiotics avert disease progression. Unfortunately, both intestinal bacterial infections and antibiotic treatment are associated with dysbiosis. This can alleviate colonization resistance, facilitate secondary infections, and potentially lead to more severe illness. To address the consequences in the context of an EHEC infection, we used the established mouse infection model organism Citrobacter rodentium ϕstx2dact and monitored changes in fecal microbiota composition during infection and antibiotic treatment. C. rodentium ϕstx2dact infection resulted in minor changes compared to antibiotic treatment. The infection caused clear alterations in the microbial community, leading mainly to a reduction of Muribaculaceae and a transient increase in Enterobacteriaceae distinct from Citrobacter. Antibiotic treatments of the infection resulted in marked and distinct variations in microbiota composition, diversity, and dispersion. Enrofloxacin and trimethoprim/sulfamethoxazole, which did not prevent Shiga toxin-mediated organ damage, had the least disruptive effects on the intestinal microbiota, while kanamycin and tetracycline, which rapidly cleared the infection without causing organ damage, caused a severe reduction in diversity. Kanamycin treatment resulted in the depletion of all but Bacteroidetes genera, whereas tetracycline effects on Clostridia were less severe. Together, these data highlight the need to address the impact of individual antibiotics in the clinical care of life-threatening infections and consider microbiota-regenerating therapies.IMPORTANCEUnderstanding the impact of antibiotic treatment on EHEC infections is crucial for appropriate clinical care. While discouraged by early studies, recent findings suggest certain antibiotics can impede disease progression. Here, we investigated the impact of individual antibiotics on the fecal microbiota in the context of an established EHEC mouse model using C. rodentium ϕstx2dact. The infection caused significant variations in the microbiota, leading to a transient increase in Enterobacteriaceae distinct from Citrobacter. However, these effects were minor compared to those observed for antibiotic treatments. Indeed, antibiotics that most efficiently cleared the infection also had the most detrimental effect on the fecal microbiota, causing a substantial reduction in microbial diversity. Conversely, antibiotics showing adverse effects or incomplete bacterial clearance had a reduced impact on microbiota composition and diversity. Taken together, our findings emphasize the delicate balance required to weigh the harmful effects of infection and antibiosis in treatment.

Prenatal antibiotics exposure and preschoolers' internalizing and externalizing problems: A biomonitoring-based prospective birth cohort study

BACKGROUND

Biomonitoring-based epidemiological studies on prenatal antibiotic exposure and behavioral problems in preschoolers are lacking. The present study aimed to investigate the relationship between prenatal antibiotic exposure and internalizing and externalizing problems in preschoolers.

METHODS

Data from 2449 mother-child pairs were analyzed. Urine samples were repeatedly collected across three trimesters, and 43 antibiotics and 2 metabolites were measured, including preferred as veterinary antibiotics (PVAs), VAs, preferred as human antibiotics and human antibiotics. Preschoolers' internalizing and externalizing problems were evaluated by the Achenbach Child Behavior Checklist. Poisson regression models with generalized estimating equations were used to estimate risk ratios (RRs) and 95 % confidence intervals (CIs) for preschoolers' internalizing, externalizing and total problems across tertiles of antibiotic concentrations during three periods of pregnancy, and performed several subgroup analyses.

RESULTS

First-trimester urinary oxytetracycline (RR = 1.69, 95%CI: 1.20, 2.39, P-FDR = 0.011), tetracycline (RR = 1.91, 95%CI: 1.36, 2.68, P-FDR < 0.001), doxycycline (RR = 1.66, 95%CI: 1.28, 2.17, P-FDR < 0.001) and PVAs (RR = 1.79, 95%CI: 1.29, 2.48, P-FDR < 0.001) concentrations in the highest tertile were related to an elevated risk of internalizing problems compared with concentrations in the lowest tertile. First-trimester urinary doxycycline concentrations in the third tertile were also associated with an increased risk of externalizing problems compared with the first tertile (RR = 2.00, 95%CI: 1.28, 3.15, P-FDR = 0.042). Compared with concentrations in the lowest tertile, first-trimester urinary doxycycline (RR = 1.63, 95%CI: 1.19, 2.22, P-FDR = 0.028) and PVAs (RR = 1.67, 95%CI: 1.14, 2.43, P-FDR = 0.047) concentrations in the middle tertile were related to an increased risk of total problems. Furthermore, the type of main caregiver and children's outdoor activities time modified the relationships between specific prenatal antibiotic exposure and preschoolers' behavioral problems.

CONCLUSIONS

Exposure to specific antibiotics during the first trimester may be related to an increased risk of internalizing and externalizing problems in preschoolers.

Diagnosis and Management of Gastrointestinal Manifestations in Children with Cystic Fibrosis

Cystic fibrosis (CF) is primarily known for its pulmonary consequences, which are extensively explored in the existing literature. However, it is noteworthy that individuals with CF commonly display gastrointestinal (G-I) manifestations due to the substantial presence of the cystic fibrosis transmembrane conductance regulator (CFTR) protein in the intestinal tract. Recognized as pivotal nonpulmonary aspects of CF, G-I manifestations exhibit a diverse spectrum. Identifying and effectively managing these manifestations are crucial for sustaining health and influencing the overall quality of life for CF patients. This review aims to synthesize existing knowledge, providing a comprehensive overview of the G-I manifestations associated with CF. Each specific G-I manifestation, along with the diagnostic methodologies and therapeutic approaches, is delineated, encompassing the impact of innovative treatments targeting the fundamental effects of CF on the G-I tract. The findings underscore the imperative for prompt diagnosis and meticulous management of G-I manifestations, necessitating a multidisciplinary team approach for optimal care and enhancement of the quality of life for affected individuals. In conclusion, the authors emphasize the urgency for further clinical studies to establish a more robust evidence base for managing G-I symptoms within the context of this chronic disease. Such endeavors are deemed essential for advancing understanding and refining the clinical care of CF patients with G-I manifestations.

Small Intestinal Goblet Cells Control Humoral Immune Responses and Mobilization During Enteric Infection

Humoral immune responses within the gut play diverse roles including pathogen clearance during enteric infections, maintaining tolerance, and facilitating the assemblage and stability of the gut microbiota. How these humoral immune responses are initiated and contribute to these processes are well studied. However, the signals promoting the expansion of these responses and their rapid mobilization to the gut mucosa are less well understood. Intestinal goblet cells form goblet cell-associated antigen passages (GAPs) to deliver luminal antigens to the underlying immune system and facilitate tolerance. GAPs are rapidly inhibited during enteric infection to prevent inflammatory responses to innocuous luminal antigens. Here we interrogate GAP inhibition as a key physiological response required for effective humoral immunity. Independent of infection, GAP inhibition resulted in enrichment of transcripts representing B cell recruitment, expansion, and differentiation into plasma cells in the small intestine (SI), which were confirmed by flow cytometry and ELISpot assays. Further we observed an expansion of isolated lymphoid follicles within the SI, as well as expansion of plasma cells in the bone marrow upon GAP inhibition. S1PR1-induced blockade of leukocyte trafficking during GAP inhibition resulted in a blunting of SI plasma cell expansion, suggesting that mobilization of plasma cells from the bone marrow contributes to their expansion in the gut. However, luminal IgA secretion was only observed in the presence of S. typhimurium infection, suggesting that although GAP inhibition mobilizes a mucosal humoral immune response, a second signal is required for full effector function. Overriding GAP inhibition during enteric infection abrogated the expansion of laminar propria IgA+ plasma cells. We conclude that GAP inhibition is a required physiological response for efficiently mobilizing mucosal humoral immunity in response to enteric infection.

Pathogenesis and therapeutic opportunities of gut microbiome dysbiosis in critical illness

For many years, it has been hypothesized that pathological changes to the gut microbiome in critical illness is a driver of infections, organ dysfunction, and other adverse outcomes in the intensive care unit (ICU). The advent of contemporary microbiome methodologies and multi-omics tools have allowed researchers to test this hypothesis by dissecting host-microbe interactions in the gut to better define its contribution to critical illness pathogenesis. Observational studies of patients in ICUs have revealed that gut microbial communities are profoundly altered in critical illness, characterized by markedly reduced alpha diversity, loss of commensal taxa, and expansion of potential pathogens. These key features of ICU gut dysbiosis have been associated with adverse outcomes including life-threatening hospital-acquired (nosocomial) infections. Current research strives to define cellular and molecular mechanisms connecting gut dysbiosis with infections and other outcomes, and to identify opportunities for therapeutic modulation of host-microbe interactions. This review synthesizes evidence from studies of critically ill patients that have informed our understanding of intestinal dysbiosis in the ICU, mechanisms linking dysbiosis to infections and other adverse outcomes, as well as clinical trials of microbiota-modifying therapies. Additionally, we discuss novel avenues for precision microbial therapeutics to combat nosocomial infections and other life-threatening complications of critical illness.

Bacteroides fragilis toxin expression enables lamina propria niche acquisition in the developing mouse gut

Bacterial toxins are well-studied virulence factors; however, recent studies have revealed their importance in bacterial niche adaptation. Enterotoxigenic Bacteroides fragilis (ETBF) expresses B. fragilis toxin (BFT) that we hypothesized may contribute to both colonic epithelial injury and niche acquisition. We developed a vertical transmission model for ETBF in mice that showed that BFT enabled ETBF to access a lamina propria (LP) niche during colonic microbiome development that was inaccessible to non-toxigenic B. fragilis. LP entry by ETBF required BFT metalloprotease activity, and showed temporal restriction to the pre-weaning period, dependent on goblet-cell-associated passages. In situ single-cell analysis showed bft expression at the apical epithelial surface and within the LP. BFT expression increased goblet cell number and goblet-cell-associated passage formation. These findings define a paradigm by which bacterial toxin expression specifies developmental niche acquisition, suggesting that a selective advantage conferred by a toxin may impact long-term host health.

Neonatal intestinal colonization of Streptococcus agalactiae and the multiple modes of protection limiting translocation

Streptococcus agalactiae, also known as Group B Streptococcus (GBS), is a predominant pathogen of neonatal sepsis, commonly associated with early-onset neonatal sepsis. GBS has also been associated with cases of late-onset sepsis potentially originating from the intestine. Previous findings have shown GBS can colonize the infant intestinal tract as part of the neonatal microbiota. To better understand GBS colonization dynamics in the neonatal intestine, we collected stool and milk samples from prematurely born neonates for identification of potential pathogens in the neonatal intestinal microbiota. GBS was present in approximately 10% of the cohort, and this colonization was not associated with maternal GBS status, delivery route, or gestational weight. Interestingly, we observed the relative abundance of GBS in the infant stool negatively correlated with maternal IgA concentration in matched maternal milk samples. Using a preclinical murine model of GBS infection, we report that both vertical transmission and direct oral introduction resulted in intestinal colonization of GBS; however, translocation beyond the intestine was limited. Finally, vaccination of dams prior to breeding induced strong immunoglobulin responses, including IgA responses, which were associated with reduced mortality and GBS intestinal colonization. Taken together, we show that maternal IgA may contribute to infant immunity by limiting the colonization of GBS in the intestine.

A mixed-methods approach utilising electronic health records to examine antimicrobial prescription surrounding gastrointestinal clinical presentations in dogs and cats

Introduction

Systemically-administered antimicrobials are often prescribed in canine and feline gastrointestinal clinical presentations. Responsible use of antimicrobials, particularly those considered Highest Priority Critically Important Antimicrobials (HPCIAs) is vital to tackle antimicrobial resistance. Although practice-level prescription guidance is available, further strategies based on a greater understanding of antimicrobial prescription at the population-level are needed. Here, we used a mixed-methods approach, harnessing veterinary electronic health records (EHRs) to characterise the use of antimicrobials in canine and feline gastrointestinal presentations, and to explore justification and reasoning around antimicrobial prescribing, particularly of HPCIAs.

Methods

This observational study used 23,337 EHRs complemented with veterinary practitioner-completed questionnaires, from canine and feline gastrointestinal consultations from 225 volunteer UK veterinary practices between April 2014 and September 2018.

Results

A total of 83.4% (95% confidence interval (CI) 82.6-84.3) gastrointestinal presentations were reported as mild, with non-haemorrhagic diarrhoea and vomiting the most frequently reported clinical signs. Systemically-administered antimicrobials occurred in 28.6% of canine (95% CI 26.9-30.3) and 22.4% of feline (95% CI 20.4-24.4) gastrointestinal consultations, with HPCIA prescription occurring more frequently in cats. Results of multivariable analysis showed the presence of non-haemorrhagic diarrhoea (canine Odds Ratio (OR) 2.1, 95% CI 1.9-2.3; feline OR 1.8, 95% CI 1.5-2.1), haemorrhagic diarrhoea (canine OR 4.2, 95% CI 3.8-4.7; feline OR 3.1, 95% CI 2.4-3.8), and moderate/severe presentations (canine OR 1.9, 95% CI 1.7-2.8; feline OR 2.0, 95% CI 1.7-2.5) were positively associated with receiving a systemically-administered antimicrobial. Thematic analysis of clinical narrative content of 516 gastrointestinal consultations where HPCIAs were prescribed allowed the identification of ten factors underpinning reasoning or decision-making for HPCIA prescription: perceived animal/owner compliance; owner's expectations; perceived risk of infection; clinical signs; recent clinical history; perceived positive previous response to antimicrobial therapy; geriatric patients and euthanasia; concomitant conditions; diagnostic testing and the behavioral trend to trial antimicrobial therapy empirically in gastrointestinal cases. No explicit justification for HPCIA prescription was recorded in 77% of cases.

Discussion

Improving recorded justification represents a clear target for stewardship programmes. By utilising a complementary mixed-methods approach to EHRs, this study unlocks previously untapped data recorded within EHRs. These results can help inform targeted interventions, contributing towards enhanced antimicrobial stewardship.

Gut microbiota induces weight gain and inflammation in the gut and adipose tissue independent of manipulations in diet, genetics, and immune development

Obesity and the metabolic syndrome are complex disorders resulting from multiple factors including genetics, diet, activity, inflammation, and gut microbes. Animal studies have identified roles for each of these, however the contribution(s) specifically attributed to the gut microbiota remain unclear, as studies have used combinations of genetically altered mice, high fat diet, and/or colonization of germ-free mice, which have an underdeveloped immune system. We investigated the role(s) of the gut microbiota driving obesity and inflammation independent of manipulations in diet and genetics in mice with fully developed immune systems. We demonstrate that the human obese gut microbiota alone was sufficient to drive weight gain, systemic, adipose tissue, and intestinal inflammation, but did not promote intestinal barrier leak. The obese microbiota induced gene expression promoting caloric uptake/harvest but was less effective at inducing genes associated with mucosal immune responses. Thus, the obese gut microbiota is sufficient to induce weight gain and inflammation.

Antibiotic-induced collateral damage to the microbiota and associated infections

Antibiotics have transformed medicine, saving millions of lives since they were first used to treat a bacterial infection. However, antibiotics administered to target a specific pathogen can also cause collateral damage to the patient's resident microbial population. These drugs can suppress the growth of commensal species which provide protection against colonization by foreign pathogens, leading to an increased risk of subsequent infection. At the same time, a patient's microbiota can harbour potential pathogens and, hence, be a source of infection. Antibiotic-induced selection pressure can cause overgrowth of resistant pathogens pre-existing in the patient's microbiota, leading to hard-to-treat superinfections. In this Review, we explore our current understanding of how antibiotic therapy can facilitate subsequent infections due to both loss of colonization resistance and overgrowth of resistant microorganisms, and how these processes are often interlinked. We discuss both well-known and currently overlooked examples of antibiotic-associated infections at various body sites from various pathogens. Finally, we describe ongoing and new strategies to overcome the collateral damage caused by antibiotics and to limit the risk of antibiotic-associated infections.

Influence of konjac glucomannan and its derivatives on the oral pharmacokinetics of antimicrobial agent in antibiotics cocktails: Keep vigilant on dietary fiber supplement

In this study, konjac glucomannan (KGM) and its derivatives were gavaged as dietary fiber supplements, followed by a single dose of antibiotic cocktail (Abx) containing amoxicillin, neomycin, metronidazole and vancomycin in mice. The effects of dietary fiber on the pharmacokinetics and tissue distribution of each antibiotic were investigated. The results showed that the specific effects of KGM and its derivatives on the absorption, distribution, and elimination of certain antibiotics varied and depended on the nature of the fibers and the characteristics of the antibiotics. Explicitly, the ingestion of KGM and its derivatives enhanced the absorption of metronidazole by 1.7 times and hindered that of amoxicillin by nearly 36 % without affecting the absorption of neomycin sulfate and vancomycin. KGM and its derivatives had no effect on the distribution of amoxicillin and metronidazole, but DKGM and KGM hindered the distributions of neomycin sulfate (from 1.25 h to 1.62 h) and vancomycin (from 0.95 h to 1.14 h), respectively. KGM and its derivatives promoted the elimination of amoxicillin by nearly 38 % while prolonging that of metronidazole by >50 %. KOGM boosted the elimination of neomycin sulfate and vancomycin, but KGM differed from DKGM in acting on the elimination of both.

Microbiota DNA Translocation Into Mesentery Lymph Nodes Is Associated With Early Development of Pouchitis After IPAA for Ulcerative Colitis

BACKGROUND

The role of bacterial translocation in Crohn's disease has been extensively studied. However, data regarding bacterial translocation into the mesentery in patients with ulcerative colitis were scarce.

OBJECTIVE

This study aimed to explore the relationship between bacterial translocation and postoperative outcome by comparing the microbiome profile of different anatomical sites in patients with ulcerative colitis who underwent proctocolectomy and IPAA.

DESIGN

A prospective study.

SETTING

This study was conducted at the Jinling Hospital from August 2017 to May 2018.

PATIENTS

Samples of 27 patients with ulcerative colitis who had IPAA and 15 healthy controls who underwent routine colonoscopy were collected.

MAIN OUTCOME MEASURES

The microbiome profile of different tissue sites and short- and long-term outcomes after IPAA in patients with ulcerative colitis.

RESULTS

Bacterial DNA was detected in mesenteric lymph nodes of 51.9% of patients with ulcerative colitis (14/27) and in mesenteric adipose tissue of 66.7% of patients (18/27). The microbiome in mesenteric lymph nodes and mesenteric adipose tissue resembled the mucosal microbiome to a greater extent than the fecal microbiome. Positive bacterial DNA in mesenteric lymph nodes (8/14 vs 0/13; p = 0.002) was associated with pouchitis within 12 months after IPAA, whereas Bray-Curtis distance in mesenteric lymph nodes was significantly different between patients with pouchitis and without ( p = 0.009).

LIMITATIONS

This study was limited by its small sample size and lacked situ experiment to confirm the true bacterial translation.

CONCLUSIONS

Bacterial translocation was highly prevalent in patients with ulcerative colitis. The translocated bacteria DNA in mesenteric adipose tissue and mesenteric lymph nodes was highly correlated and more likely to originate from mucosal than fecal microbiome. Also, the extent of bacterial translocation and translocation of certain bacteria might be associated with the early development of pouchitis after IPAA. This might represent an unprecedented technique to predict pouchitis using mesenteric lymph node bacterial profiles. See Video Abstract at http://links.lww.com/DCR/C119 .

LA TRANSLOCACIN DEL ADN DE LA MICROBIOTA EN LOS GANGLIOS LINFTICOS DEL MESENTERIO SE ASOCIA CON EL DESARROLLO TEMPRANO DE POUCHITIS DESPUS DE IPAA PARA LA COLITIS ULCEROSA

ANTECEDENTES:El papel de la translocación bacteriana en la enfermedad de Crohn se ha estudiado ampliamente en los últimos años. Sin embargo, los datos sobre la translocación bacteriana en el mesenterio en pacientes con colitis ulcerosa fueron escasos.OBJETIVO:El objetivo de este estudio fue explorar la relación entre la translocación bacteriana y el resultado postoperatorio comparando el perfil del microbioma de diferentes sitios anatómicos en pacientes con colitis ulcerosa que se sometieron a proctocolectomía y anastomosis ileoanal con bolsa.DISEÑO:Estudio prospectivo.AJUSTE:Este estudio se realizó en el Hospital Jinling desde agosto de 2017 hasta mayo de 2018.PACIENTES:Se recogieron muestras de 27 pacientes con colitis ulcerosa que tenían anastomosis de bolsa ileoanal y 15 controles sanos que se sometieron a una colonoscopia de rutina.PRINCIPALES MEDIDAS DE RESULTADO:El perfil del microbioma de diferentes sitios de tejido y los resultados a corto y largo plazo después de la anastomosis ileoanal con bolsa en pacientes con colitis ulcerosa.RESULTADOS:Se detectó ADN bacteriano en los ganglios linfáticos mesentéricos del 51,9 % (14/27) de los pacientes con colitis ulcerosa y en el tejido adiposo mesentérico del 66,7 % (18/27) de los pacientes, respectivamente. El microbioma en los ganglios linfáticos mesentéricos y el tejido adiposo mesentérico se parecía más al microbioma de la mucosa que al microbioma fecal. El ADN bacteriano translocado en los ganglios linfáticos mesentéricos y el tejido adiposo mesentérico estaban altamente correlacionados. El ADN bacteriano positivo en los ganglios linfáticos mesentéricos (8/14 frente a 0/13, p = 0,002) se asoció con reservoritis dentro de los 12 meses posteriores a la anastomosis ileoanal con reservorio, mientras que la distancia de Bray-Curtis en los ganglios linfáticos mesentéricos fue significativamente diferente entre reservoritis y no reservorios. -pacientes con reservorio (p = 0,009). Ruminococcus, Bacteroides y Clostridiales se encontraron exclusivamente en los ganglios linfáticos mesentéricos de pacientes con reservoritis.LIMITACIÓN:Este estudio estuvo limitado por el pequeño tamaño de la muestra y la falta de un experimento in situ para confirmar la verdadera traducción bacteriana.CONCLUSIÓN:La translocación bacteriana fue altamente prevalente en pacientes con colitis ulcerosa. El ADN bacteriano translocado en el tejido adiposo mesentérico y los ganglios linfáticos mesentéricos estaba altamente correlacionado y era más probable que se originara en el microbioma de la mucosa que en el fecal. Además, la extensión de la translocación bacteriana y la translocación de ciertas bacterias podría estar asociada con el desarrollo temprano de reservoritis después de la anastomosis del reservorio ileoanal. Esto podría representar una técnica sin precedentes para predecir la reservoritis utilizando perfiles bacterianos de los ganglios linfáticos mesentéricos. Consulte Video Resumen en. http://links.lww.com/DCR/C119(Traducción-Dr. Felipe Bellolio ).

Low dietary fiber intake impairs small intestinal Th17 and intraepithelial T cell development over generations

Dietary fiber strongly impacts the microbiota. Here, we show that a low-fiber diet changes the small intestinal (SI) microbiota and impairs SI Th17, TCRαβ+CD8αβ+ and TCRαβ+CD8αα+ intraepithelial T cell development. We restore T cell development with dietary fiber supplementation, but this defect becomes persistent over generations with constant low-fiber diets. Offspring of low-fiber diet-fed mice have reduced SI T cells even after receiving a fiber-rich diet due to loss of bacteria important for T cell development. In these mice, only a microbiota transplant from a fiber-rich diet-fed mouse and a fiber-rich diet can restore T cell development. Low-fiber diets reduce segmented filamentous bacteria (SFB) abundance, impairing its vertical transmission. SFB colonization and a fiber-rich diet partially restore T cell development. Finally, we observe that low-fiber diet-induced T cell defects render mice more susceptible to Citrobacter rodentium infection. Together, these results demonstrate the importance of fiber to microbiota vertical transmission and host immune system development.

Effects of ammonia and roxithromycin exposure on skin mucus microbiota composition and immune response of juvenile yellow catfish Pelteobagrus fulvidraco

As an inevitable factor in aquaculture, ammonia plays a critical role in macrolide antibiotic resistance, leading to accumulating of antibiotic-resistant bacteria in fish skin mucus. In this study, four experimental groups were implemented to test the effects of ammonia alone or in combination with roxithromycin for 28 days on skin mucus microbial composition and the immune response of yellow catfish: CON (control), AN (50.00 mg L-1 total ammonia nitrogen, TA-N), ROX (100 μg L-1 roxithromycin), and HR (50.00 mg L-1 TA-N, 100 μg L-1 ROX). This study demonstrated that ammonia or roxithromycin exposure resulted in increased plasma ammonia content and decreased total antioxidant capacity. Compared with AN group, the combined exposure of ammonia and roxithromycin inhibited the skin mucus immune response. Microbial composition analysis showed that combined exposure of ammonia and roxithromycin had no significant effect on skin mucus α-diversity as compared with CON group. The abundance of Cetobacterium, Rhizobiales_Incertae_Sedis_uncultured and Acinetobacter was increased significantly with the combined effect of ammonia and roxithromycin, these bacteria may be potentially antibiotic-resistant. As compared with CON group, the combined exposure of ammonia and roxithromycin did not affect skin goblet cell counts. This study suggests that combined exposure to ammonia and ROX increases the risk of the emergence of antibiotic-resistant bacteria.

Whey and Buttermilk-Based Formulas Modulate Gut Microbiota in Mice with Antibiotic-Induced Dysbiosis

SCOPE

Diet is one of the main factors that modifies intestinal microbiota composition. The search for foods that can reverse situations of intestinal dysbiosis such as that induced by antibiotics is of great interest. Buttermilk and whey are the main by-products produced by the dairy industry containing bioactive compounds. The aim of this study is to investigate the ability of whey and buttermilk-based formulas supplemented with lactoferrin and milk fat globule membrane (MFGM) to modulate the effects of clindamycin on mouse intestinal microbiota.

METHODS AND RESULTS

Male C57BL/6 mice are treated with saline (control), clindamycin (Clin), a formula containing whey (F1) or buttermilk (F2), Clin+F1 or Clin+F2, and their fecal microbiota profiles are analyzed by sequencing of 16S rRNA gene using the MinION device. Clin induces alterations in both the composition and metabolic functions of the mice intestinal microbiota. The treatment with F1 or F2 reverses the effects of clindamycin, restoring the levels of Rikenellaceae and Lactobacillaceae families and certain pathways related to short-chain fatty acids production and tetrahydrofolate biosynthesis.

CONCLUSION

Whey and buttermilk supplemented with lactoferrin and MFGM may be a bioactive formula for functional foods to prevent or restore microbiota alterations induced by antibiotic administration.

Carbohydrate supplementation retains intestinal barrier and ameliorates bacterial translocation in an antibiotic-induced mouse model

Bacterial translocation (BT), with antibiotic use as an inducer, is associated with increased risk of developing multiple inflammatory disorders, and is closely associated with intestinal barrier integrity. Deacetylated konjac glucomannan (DKGM) and konjac oligo-glucomannan (KOGM) are two of the most widely used derivatives in the food industry. They are structurally and physiologically distinct from konjac glucomannan (KGM), and previous studies have confirmed their prebiotic effects. But whether they play a role in antibiotic-induced BT is unknown. Here, we applied an antibiotic cocktail (Abx) to a mouse model and investigated whether and how KGM and its derivatives function in BT and inflammation response amelioration during and after antibiotics, and which intervention plan is more effective. The results showed that KGM and its derivatives all inhibited BT. The colon tissue lesions caused by BT were largely alleviated, and short-chain fatty acid (SCFA) production was highly improved with the supplementation of carbohydrates. The prolonged intervention plan using KGM and its derivatives was more efficient than intervention only during the Abx administration period. Among the three dietary fibers, KGM behaved best, while DKGM and KOGM behaved equivalently. Additionally, KGM and its derivatives all reduced the inflammatory response accompanying BT, but DKGM may have a direct inhibitory efficacy in inflammation other than that through IL-10, unlike KGM or KOGM.

Goblet cell-associated antigen passage: A gatekeeper of the intestinal immune system

Effective delivery of luminal antigens to the underlying immune system is the initial step in generating antigen-specific responses in the gut. However, a large body of information regarding the immune response activation process remains unknown. Recently, goblet cells (GCs) have been reported to form goblet cell-associated antigen passages (GAPs). Luminal antigens can be transported inside GAPs and reach subepithelial immune cells to induce antigen-specific immune responses, contributing largely to gut homeostasis and the prevention of some intestinal diseases like allergic enteritis and bacterial translocation. In this article, we summarized recent observations on the formation of intestinal GAPs and their roles in mucosal immunity. We hope that this review can offer a fresh perspective and valuable insights for clinicians and researchers interested in studying the intestinal immune system.

A dose-dependent increase in the risk of inflammatory bowel disease after exposure to broad-spectrum antibiotics: A national population study in Korea

BACKGROUND

The association between antibiotic use and risk of inflammatory bowel disease (IBD), particularly among adults, remains unclear. Furthermore, there is a scarcity of data among non-Western countries.

AIMS

To investigate the association and dose-response relationships between antibiotic use and subsequent IBD risk across all ages METHODS: This population-based case-control analysis used data from the Korean National Health Insurance Service database (2004-2018). We compared 68,633 patients with new-onset IBD to matched controls (n = 343,165) using multivariable conditional logistic regression analysis. We also examined the dose-response relationship using non-linear regression analysis, and separately analysed childhood-onset IBD (aged ≤14 years) risk following early-life antibiotic exposure.

RESULTS

The mean age at diagnosis was 45.2 ± 16.8 years. Antibiotic prescriptions between 2 and 5 years before diagnosis significantly increased the odds of developing IBD (adjusted odds ratio [OR], 1.24; 95% confidence interval [CI]: 1.21-1.27). Additionally, sensitivity analysis revealed an elevated risk up to 9 years before diagnosis. Broad-spectrum antibiotics increased IBD risk, independent of gastroenteritis. A distinct dose-response relationship was observed irrespective of the IBD subtype and study population (all p < 0.001). Furthermore, antibiotic exposure within the first year of life was linked with the risk of childhood-onset IBD (OR, 1.51; 95% CI: 1.25-1.82).

CONCLUSIONS

Broad-spectrum antibiotics dose-dependently increased the risk for IBD in the Korean population. Our findings provide a fundamental epidemiological basis for identifying antibiotic use as a significant risk factor for IBD across different environmental backgrounds.

Vitamin K2 supplementation improves impaired glycemic homeostasis and insulin sensitivity for type 2 diabetes through gut microbiome and fecal metabolites

BACKGROUND

There is insufficient evidence for the ability of vitamin K2 to improve type 2 diabetes mellitus symptoms by regulating gut microbial composition. Herein, we aimed to demonstrate the key role of the gut microbiota in the improvement of impaired glycemic homeostasis and insulin sensitivity by vitamin K2 intervention.

METHODS

We first performed a 6-month RCT on 60 T2DM participants with or without MK-7 (a natural form of vitamin K2) intervention. In addition, we conducted a transplantation of the MK-7-regulated microbiota in diet-induced obesity mice for 4 weeks. 16S rRNA sequencing, fecal metabolomics, and transcriptomics in both study phases were used to clarify the potential mechanism.

RESULTS

After MK-7 intervention, we observed notable 13.4%, 28.3%, and 7.4% reductions in fasting serum glucose (P = 0.048), insulin (P = 0.005), and HbA1c levels (P = 0.019) in type 2 diabetes participants and significant glucose tolerance improvement in diet-induced obesity mice (P = 0.005). Moreover, increased concentrations of secondary bile acids (lithocholic and taurodeoxycholic acid) and short-chain fatty acids (acetic acid, butyric acid, and valeric acid) were found in human and mouse feces accompanied by an increased abundance of the genera that are responsible for the biosynthesis of these metabolites. Finally, we found that 4 weeks of fecal microbiota transplantation significantly improved glucose tolerance in diet-induced obesity mice by activating colon bile acid receptors, improving host immune-inflammatory responses, and increasing circulating GLP-1 concentrations.

CONCLUSIONS

Our gut-derived findings provide evidence for a regulatory role of vitamin K2 on glycemic homeostasis, which may further facilitate the clinical implementation of vitamin K2 intervention for diabetes management.

TRIAL REGISTRATION

The study was registered at https://www.chictr.org.cn (ChiCTR1800019663).

Mesenteric Adipose Tissue-Derived Klebsiella variicola Disrupts Intestinal Barrier and Promotes Colitis by Type VI Secretion System

Mesenteric adipose tissue (MAT) in Crohn's disease (CD) is associated with transmural inflammation. Extended mesenteric excision can reduce surgical recurrence and improve long-term outcomes, indicating that MAT plays an important role in the pathogenesis of CD. Bacterial translocation has been reported to occur in the MAT of patients with CD (CD-MAT), but the mechanisms by which translocated bacteria lead to intestinal colitis remain unclear. Here it is shown that members of Enterobacteriaceae are highly enriched in CD-MAT compared with non-CD controls. Viable Klebsiella variicola in Enterobacteriaceae is isolated exclusively in CD-MAT and can induce a pro-inflammatory response in vitro and exacerbates colitis both in dextran sulfate sodium (DSS)-induced colitis mice model and IL-10^-/- spontaneous colitis mice model. Mechanistically, active type VI secretion system (T6SS) is identified in the genome of K. variicola, which can impair the intestinal barrier by inhibiting the zonula occludens (ZO-1) expression. Dysfunction of T6SS by CRISPR interference system alleviates the inhibitory effect of K. variicola on ZO-1 expression and attenuated colitis in mice. Overall, these findings demonstrate that a novel colitis-promoting bacteria exist in the mesenteric adipose tissue of CD, opening a new therapeutic avenue for colitis management.

Intestinal Flora Metabolite Trimethylamine Oxide Is Inextricably Linked to Coronary Heart Disease

ABSTRACT

Atherosclerotic coronary heart disease is a common cardiovascular disease with high morbidity and mortality. In recent years, the incidence of coronary heart disease has gradually become younger, and biomarkers for predicting coronary heart disease have demonstrated valuable clinical prospects. Several studies have established an association between coronary heart disease and intestinal flora metabolites, including trimethylamine oxide (TMAO), which has attracted widespread attention from researchers. Investigations have also shown that plasma levels of TMAO and its precursors can predict cardiovascular risk in humans; however, TMAO's mechanism of action in causing coronary heart disease is not fully understood. This review examines TMAO's generation, the mechanism through which it causes coronary heart disease, and the approaches used to treat TMAO-caused coronary heart disease to possible avenues for future research on coronary heart disease and find new concepts for the treatment of the condition.

Children with malignancies and septic shock - an attempt to understand the risk factors

OBJECTIVES

To explain the high mortality of septic shock in children with cancer.

METHODS

A retrospective cohort from 2016 to 2020, of children aged 0 to 18 years, and septic shock.

RESULTS

The authors included 139 patients. Acute lymphocytic leukemia was the most frequent diagnosis (16.5%), and Gram-negative bacteria were the most frequent blood culture isolates (22.3%). There were 57 deaths in ICU (41%), 10 in the first 24 hours of shock (early death). A LASSO model with variables: neutropenia (coefficient 0.215), respiratory (0.81), hematological (1.41), and neurological (0.72) dysfunctions, age (-0.002) and solid tumor recurrence (0.34) generated AUC = 0.79 for the early death outcome. Survivors had significant differences in the PRISM-IV score (mean ± SD 10.9 ± 6.2 in the survivors, 14.1 ± 6.5 in the deceased, p = 0.004), and in the mean number of organ dysfunctions (3.2 ± 1.1 in the survivors, 3.8 ± 6.5 in the deceased, p < 0.001). A positive fluid balance in the first 24 hours of sepsis between 2% and 6% of body weight showed a reduction effect on the probability of death in ICU (hazard ratio 0.47, 95% CI 0.24-0.92, p = 0.027). The recurrence of any cancer was a predictor of in-hospital death, regardless of severity.

CONCLUSIONS

Recurrence of any cancer is an important risk of sepsis-related death. A positive fluid balance between 20 and 60 mL/kg or 2% and 6% of body weight in the first 24 hours after the onset of sepsis is related to lower mortality.

Autophagy and the Insulin-like Growth Factor (IGF) System in Colonic Cells: Implications for Colorectal Neoplasia

Colorectal cancer (CRC) is one of the most common human malignancies worldwide. Along with apoptosis and inflammation, autophagy is one of three important mechanisms in CRC. The presence of autophagy/mitophagy in most normal mature intestinal epithelial cells has been confirmed, where it has mainly protective functions against reactive oxygen species (ROS)-induced DNA and protein damage. Autophagy regulates cell proliferation, metabolism, differentiation, secretion of mucins and/or anti-microbial peptides. Abnormal autophagy in intestinal epithelial cells leads to dysbiosis, a decline in local immunity and a decrease in cell secretory function. The insulin-like growth factor (IGF) signaling pathway plays an important role in colorectal carcinogenesis. This is evidenced by the biological activities of IGFs (IGF-1 and IGF-2), IGF-1 receptor type 1 (IGF-1R) and IGF-binding proteins (IGF BPs), which have been reported to regulate cell survival, proliferation, differentiation and apoptosis. Defects in autophagy are found in patients with metabolic syndrome (MetS), inflammatory bowel diseases (IBD) and CRC. In neoplastic cells, the IGF system modulates the autophagy process bidirectionally. In the current era of improving CRC therapies, it seems important to investigate the exact mechanisms not only of apoptosis, but also of autophagy in different populations of tumor microenvironment (TME) cells. The role of the IGF system in autophagy in normal as well as transformed colorectal cells still seems poorly understood. Hence, the aim of the review was to summarize the latest knowledge on the role of the IGF system in the molecular mechanisms of autophagy in the normal colon mucosa and in CRC, taking into account the cellular heterogeneity of the colonic and rectal epithelium.

STAT3 signaling in prostate cancer progression and therapy resistance: An oncogenic pathway with diverse functions

The categorization of cancers demonstrates that prostate cancer is the most common malignancy in men and it causes high death annually. Prostate cancer patients are diagnosed mainly via biomarkers such as PSA test and patients show poor prognosis. Prostate cancer cells rapidly diffuse into different parts of body and their metastasis is also a reason for death. Current therapies for prostate cancer patients include chemotherapy, surgery and radiotherapy as well as targeted therapy. The progression of prostate cancer cells is regulated by different factors that STAT3 signaling is among them. Growth factors and cytokines such as IL-6 can induce STAT3 signaling and it shows carcinogenic impact. Activation of STAT3 signaling occurs in prostate cancer and it promotes malignant behavior of tumor cells. Induction of STAT3 signaling increases glycolysis and proliferation of prostate cancer cells and prevents apoptosis. Furthermore, STAT3 signaling induces EMT mechanism in increasing cancer metastasis. Activation of STAT3 signaling stimulates drug resistance and the limitation of current works is lack of experiment related to role of STAT3 signaling in radio-resistance in prostate tumor. Calcitriol, capsazepine and β-elemonic are among the compounds capable of targeting STAT3 signaling and its inhibition in prostate cancer therapy. In addition to natural products, small molecules targeting STAT3 signaling have been developed in prostate cancer therapy.

Fecal microbiota transplantation and short-chain fatty acids reduce sepsis mortality by remodeling antibiotic-induced gut microbiota disturbances

Objective

Sepsis is the leading cause of death in critically ill patients. The gastrointestinal tract has long been thought to play an important role in the pathophysiology of sepsis. Antibiotic therapy can reduce a patient's commensal bacterial population and raise their risk of developing subsequent illnesses, where gut microbiota dysbiosis may be a key factor.

Methods

In this study, we analyzed the 16S rRNA of fecal samples from both healthy people and patients with sepsis to determine if alterations in gut bacteria are associated with sepsis. Then, we developed a mouse model of sepsis using cecal ligation and puncture (CLP) in order to examine the effects of fecal microbiota transplantation (FMT) and short-chain fatty acids (SCFAs) on survival rate, systemic inflammatory response, gut microbiota, and mucosal barrier function.

Results

Sepsis patients' gut microbiota composition significantly differed from that of healthy people. At the phylum level, the amount of Proteobacteria in the intestinal flora of sepsis patients was much larger than that of the control group, whereas the number of Firmicutes was significantly lower. Mice with gut microbiota disorders (ANC group) were found to have an elevated risk of death, inflammation, and organ failure as compared to CLP mice. However, all of these could be reversed by FMT and SCFAs. FMT and SCFAs could regulate the abundance of bacteria such as Firmicutes, Proteobacteria, Escherichia Shigella, and Lactobacillus, restoring them to levels comparable to those of healthy mice. In addition, they increased the expression of the Occludin protein in the colon of mice with sepsis, downregulated the expression of the NLRP3 and GSDMD-N proteins, and reduced the release of the inflammatory factors IL-1β and IL-18 to inhibit cell pyroptosis, ultimately playing a protective role in sepsis.

Disccusion

FMT and SCFAs provide a microbe-related survival benefit in a mouse model of sepsis, suggesting that they may be a viable treatment for sepsis.

Cystic Fibrosis-Related Gut Dysbiosis: A Systematic Review

BACKGROUND AND AIMS

Cystic Fibrosis (CF) is associated with gut dysbiosis, local and systemic inflammation, and impaired immune function. Gut microbiota dysbiosis results from changes in the complex gut milieu in response to CF transmembrane conductance regulator (CFTR) dysfunction, pancreatic malabsorption, diet, medications, and environmental influences. In several diseases, alteration of the gut microbiota influences local and systemic inflammation and disease outcomes. We conducted a systematic review of the gut microbiota in CF and explored factors influencing dysbiosis.

METHODS

An electronic search of three databases was conducted in January 2019, and re-run in June 2021. Human, animal, and in vitro studies were included. The primary outcome was differences in the gut microbiota between people with CF (pwCF) and healthy controls. Secondary outcomes included the relationship between the gut microbiota and other factors, including diet, medication, inflammation, and pulmonary function in pwCF.

RESULTS

Thirty-eight studies were identified. The literature confirmed the presence of CF-related gut dysbiosis, characterized by reduced diversity and several taxonomic changes. There was a relative increase of bacteria associated with a pro-inflammatory response coupled with a reduction of those considered anti-inflammatory. However, studies linking gut dysbiosis to systemic and lung inflammation were limited. Causes of gut dysbiosis were multifactorial, and findings were variable. Data on the impact of CFTR modulators on the gut microbiota were limited.

CONCLUSIONS

CF-related gut dysbiosis is evident in pwCF. Whether this influences local and systemic disease and is amenable to interventions with diet and drugs, such as CFTR modulators, requires further investigation.

Detergent exposure induces epithelial barrier dysfunction and eosinophilic inflammation in the esophagus

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic allergic disease associated with type 2 inflammation and epithelial barrier dysfunction. The etiology is unknown, however, genetic heritability studies suggest environmental factors play a key role in pathogenesis. Detergents, such as sodium dodecyl sulfate (SDS), are common ingredients in household products such as dish soap and toothpaste. We hypothesized detergent exposure decreases epithelial barrier function and induces esophageal inflammation.

METHODS

Immortalized esophageal epithelial cells (EPC2) were cultured in air-liquid interface (ALI) and exposed to SDS. Barrier function/activity was assessed by transepithelial electrical resistance (TEER), FITC-dextran flux, and RT-PCR. Additionally, SDS-treated mouse esophageal organoids were evaluated for morphology. To investigate the effects of SDS in vivo, mice were treated with 0.5% SDS in drinking water for 14 days. Esophagi were assessed by gross morphology, histopathology, protein expression, and bulk RNA sequencing.

RESULTS

When EPC2 cells were exposed to SDS (5 μg/ml) for 96 h, TEER decreased (p = 0.03), and FITC-dextran flux increased (p = 0.0002). mRNA expression of IL-33 increased 4.5-fold (p = 0.02) at 6 h and DSG1 decreased (p < 0.0001) by 72 h. Disrupted epithelial integrity was noted in SDS-treated esophageal organoids. When mice were exposed to SDS, they showed increased esophageal width, chemokine, and metalloprotease levels. Mice treated with SDS also showed increased IL-33 protein expression, basal zone hyperplasia, CD4+ cell infiltration, and esophageal eosinophilia. RNA sequencing revealed upregulation of immune response pathway genes.

CONCLUSION

Exposure to SDS decreases esophageal barrier integrity, stimulates IL-33 production, and promotes epithelial hyperplasia and tissue eosinophilia. Detergents may be a key environmental trigger in EoE pathogenesis.

The combination of ciprofloxacin and indomethacin suppresses the level of inflammatory cytokines secreted by macrophages in vitro

PURPOSE

The combined use of antibiotics and anti-inflammatory medicine to manage bacterial endotoxin-induced inflammation following injuries or diseases is increasing. The cytokine level produced by macrophages plays an important role in this treatment course. Ciprofloxacin and indomethacin, two typical representatives of antibiotics and anti-inflammatory medicine, are cost-effective and has been reported to show satisfactory effect. The current study aims to investigate the effect of ciprofloxacin along with indomethacin on the secretion of inflammatory cytokines by macrophages in vitro.

METHODS

Primary murine peritoneal macrophages and RAW 264.7 cells were administrated with lipopolysaccharide (LPS) for 24 h. The related optimal dose and time point of ciprofloxacin or indomethacin in response to macrophage inflammatory response inflammation were determined via macrophage secretion induced by LPS. Then, the effects of ciprofloxacin and indomethacin on the secretory functions and viability of various macrophages were determined by enzyme-linked immunosorbent assay and flow cytometry analysis, especially for the levels of interleukin (IL)-1β, IL-6, IL-10, and tumor necrosis factor (TNF)-α. The optimal dose and time course of ciprofloxacin affecting macrophage inflammatory response were determined by testing the maximum inhibitory effect of the drugs on pro-inflammatory factors at each concentration or time point.

RESULTS

According to the levels of cytokines secreted by various macrophages (1.2 × 10⁶ cells/well) after administration of 1 μg/mL LPS, the optimal dose and usage timing for ciprofloxacin alone were 80 μg/mL and 24 h, respectively, and the optimal dose for indomethacin alone was 10 μg/mL. Compared with the LPS-stimulated group, the combination of ciprofloxacin and indomethacin reduced the levels of IL-1β (p < 0.05), IL-6 (p < 0.05), IL-10 (p < 0.01)), and TNF-α (p < 0.01). Furthermore, there was greater stability in the reduction of inflammatory factor levels in the combination group compared with those in which only ciprofloxacin or indomethacin was used.

CONCLUSION

The combination of ciprofloxacin and indomethacin suppressed the levels of inflammatory cytokines secreted by macrophages in vitro. This study illustrates the regulatory mechanism of drug combinations on innate immune cells that cause inflammatory reactions. In addition, it provides a new potential antibacterial and anti-inflammatory treatment pattern to prevent and cure various complications in the future.

Oral antibiotics perturbation on gut microbiota after prostate biopsy

Introduction

The use of antibiotics may induce the changes in gut microbiota. Previous studies have shown conflicting results on whether the changed gut microbiota by antibiotics can be recovered. Our study aims to investigate whether the gut microbiota could be recovered after a single dose of oral co-amoxiclav before transrectal ultrasound-guided transperineal prostate biopsy (TPPBx) in 5 weeks’ time.

Methods

Fifteen patients with elevated serum prostate-specific antigen (PSA) were recruited to provide pre-antibiotic and post-antibiotic fecal samples. The V4 region of 16S rRNA was sequenced. Analysis was performed by QIIME2. Alpha- and beta-diversities were analyzed, as well as the differential enrichment by Linear discriminant analysis Effect Size (LEfSe) analysis.

Results

Both the alpha- and beta-diversities of the pre- and post-antibiotic fecal samples were significantly different. Genera that are associated with alleviation of inflammation were enriched in the pre-antibiotic fecal samples, while the inflammation-associated genera were more enriched in the post-antibiotic fecal samples.

Conclusion

A single dose of oral co-amoxiclav before TPPBx could have led to a change of gut microbiota that cannot be recovered in 5 weeks' time. Microbiome studies on prostate cancer patients should be cautioned on the use of post-prostate biopsy fecal sampling. Further studies should be conducted for the impact on gut microbiome for TPPBx alone.

Apyrase-mediated amplification of secretory IgA promotes intestinal homeostasis

Secretory immunoglobulin A (SIgA) interaction with commensal bacteria conditions microbiota composition and function. However, mechanisms regulating reciprocal control of microbiota and SIgA are not defined. Bacteria-derived adenosine triphosphate (ATP) limits T follicular helper (Tfh) cells in the Peyer's patches (PPs) via P2X7 receptor (P2X7R) and thereby SIgA generation. Here we show that hydrolysis of extracellular ATP (eATP) by apyrase results in amplification of the SIgA repertoire. The enhanced breadth of SIgA in mice colonized with apyrase-releasing Escherichia coli influences topographical distribution of bacteria and expression of genes involved in metabolic versus immune functions in the intestinal epithelium. SIgA-mediated conditioning of bacteria and enterocyte function is reflected by differences in nutrient absorption in mice colonized with apyrase-expressing bacteria. Apyrase-induced SIgA improves intestinal homeostasis and attenuates barrier impairment and susceptibility to infection by enteric pathogens in antibiotic-induced dysbiosis. Therefore, amplification of SIgA by apyrase can be leveraged to restore intestinal fitness in dysbiotic conditions.

Long-term antibiotic exposure promotes mortality after systemic fungal infection by driving lymphocyte dysfunction and systemic escape of commensal bacteria

Antibiotics are a modifiable iatrogenic risk factor for the most common human nosocomial fungal infection, invasive candidiasis, yet the underlying mechanisms remain elusive. We found that antibiotics enhanced the susceptibility to murine invasive candidiasis due to impaired lymphocyte-dependent IL-17A- and GM-CSF-mediated antifungal immunity within the gut. This led to non-inflammatory bacterial escape and systemic bacterial co-infection, which could be ameliorated by IL-17A or GM-CSF immunotherapy. Vancomycin alone similarly enhanced the susceptibility to invasive fungal infection and systemic bacterial co-infection. Mechanistically, vancomycin reduced the frequency of gut Th17 cells associated with impaired proliferation and RORγt expression. Vancomycin's effects on Th17 cells were indirect, manifesting only in vivo in the presence of dysbiosis. In humans, antibiotics were associated with an increased risk of invasive candidiasis and death after invasive candidiasis. Our work highlights the importance of antibiotic stewardship in protecting vulnerable patients from life-threatening infections and provides mechanistic insights into a controllable iatrogenic risk factor for invasive candidiasis.

Gut dysbiosis promotes prostate cancer progression and docetaxel resistance via activating NF-κB-IL6-STAT3 axis

BACKGROUND

The gut microbiota is reportedly involved in the progression and chemoresistance of various human malignancies. However, the underlying mechanisms behind how it exerts some effect on prostate cancer, as an extra-intestinal tumor, in a contact-independent way remain elusive and deserve exploration. Antibiotic exposure, one of the various factors affecting the gut microbiota community and capable of causing gut dysbiosis, is associated with multiple disorders. This study aims to preliminarily clarify the link between gut dysbiosis and prostate cancer.

RESULTS

First, we discovered that perturbing the gut microbiota by consuming broad-spectrum antibiotics in water promoted the growth of subcutaneous and orthotopic tumors in mice. Fecal microbiota transplantation could transmit the effect of antibiotic exposure on tumor growth. Then, 16S rRNA sequencing for mouse feces indicated that the relative abundance of Proteobacteria was significantly higher after antibiotic exposure. Meanwhile, intratumoral lipopolysaccharide (LPS) profoundly increased under the elevation of gut permeability. Both in vivo and in vitro experiments revealed that the NF-κB-IL6-STAT3 axis activated by intratumoral LPS facilitated prostate cancer proliferation and docetaxel chemoresistance. Finally, 16S rRNA sequencing of patients' fecal samples revealed that Proteobacteria was enriched in patients with metastatic prostate cancer and was positively correlated with plasma IL6 level, regional lymph node metastasis status, and distant metastasis status. The receiver operating characteristic (ROC) curves showed that the relative abundance of Proteobacteria had better performance than the prostate-specific antigen (PSA) level in predicting the probability of distant metastasis in prostate cancer (area under the ROC curve, 0.860; p < 0.001).

CONCLUSION

Collectively, this research demonstrated that gut dysbiosis, characterized by the enrichment of Proteobacteria due to antibiotic exposure, resulted in the elevation of gut permeability and intratumoral LPS, promoting the development of prostate cancer via the NF-κB-IL6-STAT3 axis in mice. Considering findings from human patients, Proteobacteria might act as an intestinal biomarker for progressive prostate cancer. Video Abstract.

Antibiotic Treatment during Pregnancy Alters Offspring Gut Microbiota in a Sex-Dependent Manner

This study investigated the effect of antibiotics administered to pregnant dams on offspring gut microbiome composition and metabolic capabilities, and how these changes in the microbiota may influence their immune responses in both the periphery and the brain. We orally administered a broad-spectrum antibiotic (ABX) cocktail consisting of vancomycin 0.5 mg/mL, ampicillin 1 mg/mL, and neomycin 1 mg/mL to pregnant dams during late gestation through birth. Bacterial DNA was extracted from offspring fecal samples, and 16S ribosomal RNA gene was sequenced by Illumina, followed by analysis of gut microbiota composition and PICRUSt prediction. Serum and brain tissue cytokine levels were analyzed by Luminex. Our results indicate that the ABX-cocktail led to significant diversity and taxonomic changes to the offspring's gut microbiome. In addition, the predicted KEGG and MetaCyc pathways were significantly altered in the offspring. Finally, there were decreased innate inflammatory cytokines and chemokines and interleukin (IL)-17 seen in the brains of ABX-cocktail offspring in response to lipopolysaccharide (LPS) immune challenge. Our results suggest that maternal ABX can produce long-lasting effects on the gut microbiome and neuroimmune responses of offspring. These findings support the role of the early microbiome in the development of offspring gastrointestinal and immune systems.

Antibiotic Exposure Aggravates Bacteroides-Linked Uremic Toxicity in the Gut-Kidney Axis

Epidemiological and experimental evidence has implicated a potent link between antibiotic exposure and susceptibility to various diseases. Clinically, antibiotic treatment during platinum chemotherapy is associated with poor prognosis in patients with malignancy. In the present study, mucosal antibiotic exposure was assessed for its impact on renal distress as a sequela of platinum-based chemotherapy. Clinical transcriptome dataset-based evaluations demonstrated that levels of dysbiosis-responsive genes were elevated during renal distress, indicating pathological communications between gut and kidney. Experimentally, mucosal exposure to streptomycin aggravated platinum-induced renal tubular lesions in a mouse model. Moreover, antibiotic-induced dysbiosis increased susceptibility to gut mucosal inflammation, epithelial disruption, and bacterial exposure in response to cisplatin treatment. Further investigation of the luminal microbes indicated that antibiotic-induced dysbiosis promoted the dominance of Bacteroides species. Moreover, the functional assessment of dysbiotic microbiota predicted tryptophan metabolic pathways. In particular, dysbiosis-responsive Bacteroides acidifaciens was associated with the production of the uremic toxin indoxyl sulfate and renal injuries. The results of this study including bacterial community-based evaluations provide new predictive insights into the interorgan communications and interventions against dysbiosis-associated disorders.

The Intestinal Microbiota and Metabolites in the Gut-Kidney-Heart Axis of Chronic Kidney Disease

Emerging evidences demonstrate the involvement of gut microbiota in the progression of chronic kidney disease (CKD) and CKD-associated complications including cardiovascular disease (CVD) and intestinal dysfunction. In this review, we discuss the interactions between the gut, kidney and heart in CKD state, and elucidate the significant role of intestinal microbiota in the gut-kidney-heart axis hypothesis for the pathophysiological mechanisms of these diseases, during which process mitochondria may serve as a potential therapeutic target. Dysregulation of this axis will lead to a vicious circle, contributing to CKD progression. Recent studies suggest novel therapies targeting gut microbiota in the gut-kidney-heart axis, including dietary intervention, probiotics, prebiotics, genetically engineered bacteria, fecal microbiota transplantation, bacterial metabolites modulation, antibiotics, conventional drugs and traditional Chinese medicine. Further, the identification of specific microbial communities and their corresponding pathophysiological metabolites and the illumination of the gut-kidney-heart axis may contribute to innovative basic research, clinical trials and therapeutic strategies against CKD progression and uremic complications in CKD patients.

Epithelial Heat Shock Proteins Mediate the Protective Effects of Limosilactobacillus reuteri in Dextran Sulfate Sodium-Induced Colitis

Defects in gut barrier function are implicated in gastrointestinal (GI) disorders like inflammatory bowel disease (IBD), as well as in systemic inflammation. With the increasing incidence of IBD worldwide, more attention should be paid to dietary interventions and therapeutics with the potential to boost the natural defense mechanisms of gut epithelial cells. The current study aimed to investigate the protective effects of Limosilactobacillus reuteri ATCC PTA 4659 in a colitis mouse model and delineate the mechanisms behind it. Wild-type mice were allocated to the control group; or given 3% dextran sulfate sodium (DSS) in drinking water for 7 days to induce colitis; or administered L. reuteri for 7 days as pretreatment; or for 14 days starting 7 days before subjecting to the DSS. Peroral treatment with L. reuteri improved colitis severity clinically and morphologically and reduced the colonic levels of Tumor necrosis factor-α (TNF-α) (Tnf), Interleukin 1-β (Il1β), and nterferon-γ (Ifng), the crucial pro-inflammatory cytokines in colitis onset. It also prevented the CD11b+Ly6G+ neutrophil recruitment and the skewed immune responses in mesenteric lymph nodes (MLNs) of CD11b+CD11c+ dendritic cell (DC) expansion and Foxp3+CD4+ T-cell reduction. Using 16S rRNA gene amplicon sequencing and RT-qPCR, we demonstrated a colitis-driven bacterial translocation to MLNs and gut microbiota dysbiosis that were in part counterbalanced by L. reuteri treatment. Moreover, the expression of barrier-preserving tight junction (TJ) proteins and cytoprotective heat shock protein (HSP) 70 and HSP25 was reduced by colitis but boosted by L. reuteri treatment. A shift in expression pattern was also observed with HSP70 in response to the pretreatment and with HSP25 in response to L. reuteri-DSS. In addition, the changes of HSPs were found to be correlated to bacterial load and epithelial cell proliferation. In conclusion, our results demonstrate that the human-derived L. reuteri strain 4659 confers protection in experimental colitis in young mice, while intestinal HSPs may mediate the probiotic effects by providing a supportive protein–protein network for the epithelium in health and colitis.

IL-10 Dysregulation Underlies Chemokine Insufficiency, Delayed Macrophage Response, and Impaired Healing in Diabetic Wounds

Persistent inflammation is a major contributor to healing impairment in diabetic chronic wounds. Paradoxically, diabetic wound environment during the acute phase of healing is completely different because it exhibits a reduced macrophage response owing to inadequate expression of CCL2 proinflammatory cytokine. What causes a reduction in CCL2 expression in diabetic wounds early after injury remains unknown. In this study, we report that in contrast to prolonged exposure to high glucose, which makes monocytes proinflammatory, short-term exposure to high glucose causes a rapid monocyte reprogramming, manifested by increased expression and secretion of IL-10, which in an autocrine/paracrine fashion reduces glucose uptake and transforms monocytes into an anti-inflammatory phenotype by dampening signaling through toll-like receptors. We show that IL-10 expression is significantly increased in diabetic wounds during the acute phase of healing, causing significant reductions in toll-like receptor signaling and proinflammatory cytokine production, delaying macrophage and leukocyte responses, and underlying healing impairment in diabetic wounds. Importantly, blocking IL-10 signaling during the acute phase of healing improves toll-like receptor signaling, increases proinflammatory cytokine production, enhances macrophage and leukocyte responses, and stimulates healing in diabetic wounds. We posit that anti-IL-10 strategies have therapeutic potential if added topically after surgical debridement, which resets chronic wounds into acute fresh wounds.

Sarecycline Demonstrated Reduced Activity Compared to Minocycline against Microbial Species Representing Human Gastrointestinal Microbiota

Prolonged use of broad-spectrum tetracycline antibiotics such as minocycline and doxycycline may significantly alter the gut and skin microbiome leading to dysbiosis. Sarecycline, a narrow-spectrum tetracycline-class antibiotic used for acne treatment, is hypothesized to have minimal impact on the gastrointestinal tract microbiota. We evaluated the effect of sarecycline compared to minocycline against a panel of microorganisms that reflect the diversity of the gut microbiome using in vitro minimum inhibitory concentration (MIC) and time-kill kinetic assays. Compared to minocycline, sarecycline showed less antimicrobial activity indicated by higher MIC against 10 of 12 isolates from the Bacteroidetes phylum, three out of four isolates from Actinobacteria phylum, and five of seven isolates from the Firmicutes phylum, with significantly higher MIC values against Propionibacterium freudenreichii (≥3 dilutions). In time-kill assays, sarecycline demonstrated significantly less activity against Escherichia coli compared to minocycline at all time-points (p < 0.05). Moreover, sarecycline was significantly less effective in inhibiting Candida tropicalis compared to minocycline following 20- and 22-h exposure. Furthermore, sarecycline showed significantly less activity against Lactobacillus paracasei (recently renamed as Lacticaseibacillus paracasei subsp. paracasei) (p = 0.002) and Bifidobacterium adolescentis at 48 h (p = 0.042), when compared to minocycline. Overall, sarecycline demonstrated reduced antimicrobial activity against 79% of the tested gut microorganisms, suggesting that it is less disruptive to gut microbiota compared with minocycline. Further in vivo testing is warranted.

Intestinal Inflammation and Alterations in the Gut Microbiota in Cystic Fibrosis: A Review of the Current Evidence, Pathophysiology and Future Directions

Cystic fibrosis (CF) is a life-limiting autosomal recessive multisystem disease. While its burden of morbidity and mortality is classically associated with pulmonary disease, CF also profoundly affects the gastrointestinal (GI) tract. Chronic low-grade inflammation and alterations to the gut microbiota are hallmarks of the CF intestine. The etiology of these manifestations is likely multifactorial, resulting from cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction, a high-fat CF diet, and the use of antibiotics. There may also be a bidirectional pathophysiological link between intestinal inflammation and changes to the gut microbiome. Additionally, a growing body of evidence suggests that these GI manifestations may have significant clinical associations with growth and nutrition, quality of life, and respiratory function in CF. As such, the potential utility of GI therapies and long-term GI outcomes are areas of interest in CF. Further research involving microbial modulation and multi-omics techniques may reveal novel insights. This article provides an overview of the current evidence, pathophysiology, and future research and therapeutic considerations pertaining to intestinal inflammation and alterations in the gut microbiota in CF.

What Do We Know about the Microbiome in Cystic Fibrosis? Is There a Role for Probiotics and Prebiotics?

Cystic fibrosis (CF) is a life-shortening genetic disorder that affects the cystic fibrosis transmembrane conductance regulator (CFTR) protein. In the gastrointestinal (GI) tract, CFTR dysfunction results in low intestinal pH, thick and inspissated mucus, a lack of endogenous pancreatic enzymes, and reduced motility. These mechanisms, combined with antibiotic therapies, drive GI inflammation and significant alteration of the GI microbiota (dysbiosis). Dysbiosis and inflammation are key factors in systemic inflammation and GI complications including malignancy. The following review examines the potential for probiotic and prebiotic therapies to provide clinical benefits through modulation of the microbiome. Evidence from randomised control trials suggest probiotics are likely to improve GI inflammation and reduce the incidence of CF pulmonary exacerbations. However, the highly variable, low-quality data is a barrier to the implementation of probiotics into routine CF care. Epidemiological studies and clinical trials support the potential of dietary fibre and prebiotic supplements to beneficially modulate the microbiome in gastrointestinal conditions. To date, limited evidence is available on their safety and efficacy in CF. Variable responses to probiotics and prebiotics highlight the need for personalised approaches that consider an individual’s underlying microbiota, diet, and existing medications against the backdrop of the complex nutritional needs in CF.

Identification of Gut Bacteria such as Lactobacillus johnsonii that Disseminate to Systemic Tissues of Wild Type and MyD88-/- Mice

In healthy hosts the gut microbiota is restricted to gut tissues by several barriers some of which require MyD88-dependent innate immune sensor pathways. Nevertheless, some gut taxa have been reported to disseminate to systemic tissues. However, the extent to which this normally occurs during homeostasis in healthy organisms is still unknown. In this study, we recovered viable gut bacteria from systemic tissues of healthy wild type (WT) and MyD88^-/- mice. Shotgun metagenomic-sequencing revealed a marked increase in the relative abundance of L. johnsonii in intestinal tissues of MyD88^-/- mice compared to WT mice. Lactobacillus johnsonii was detected most frequently from multiple systemic tissues and at higher levels in MyD88^-/- mice compared to WT mice. Viable L. johnsonii strains were recovered from different cell types sorted from intestinal and systemic tissues of WT and MyD88^-/- mice. L. johnsonii could persist in dendritic cells and may represent murine immunomodulatory endosymbionts.