Current status of bacterial translocation as a cause of surgical sepsis

Bifidobacterium longum subsp. infantis YLGB-1496-Toxicological evaluation

Bifidobacterium infantis YLGB-1496, originally isolated from breast milk from a Taiwanese mother, is under study for use as a probiotic. As part of safety assessment, an Ames, in vivo mouse micronucleus, and in vivo mouse spermatocyte chromosome aberration assay were conducted along with a 13-week oral rat toxicity study. B. infantis YLGB-1496 had no activity in any of the genotoxicity assays. Administration of the bacteria to Sprague-Dawley rats at doses ranging from 0 to 1.5 g/kg bw/day had no treatment-related effects on any of the endpoints measured. There appear to be no concerns for translocation or pathogenicity of B. infantis YLGB-1496 based on extensive experience with the species in general. The results of the current investigations support potential use of B. infantis YLGB-1496 as a probiotic in infant formula.

Short-sighted evolution of virulence for invasive gut microbes: From hypothesis to tests

Why microbes harm their hosts is a fundamental question in evolutionary biology with broad relevance to our understanding of infectious diseases. Several hypotheses have been proposed to explain this "evolution of virulence." In this perspective, we reexamine one of these hypotheses in the specific context of the human gut microbiome, namely short-sighted evolution. According to the short-sighted evolution hypothesis, virulence is a product of niche expansion within a colonized host, whereby variants of commensal microbes establish populations in tissues and sites where the infection causes morbidity or mortality. This evolution is short-sighted in that the evolved variants that infect those tissues and sites are not transmitted to other hosts. The specific hypothesis that we propose is that some bacteria responsible for invasive infections and disease are the products of the short-sighted evolution of commensal bacteria residing in the gut microbiota. We present observations in support of this hypothesis and discuss the challenges inherent in assessing its general application to infections and diseases associated with specific members of the gut microbiota. We then describe how this hypothesis can be tested using genomic data and animal model experiments and outline how such studies will serve to provide fundamental information about both the evolution and genetic basis of virulence, and the bacteria of intensively studied yet poorly understood habitats including the gut microbiomes of humans and other mammals.

Concurrent Bacteremia and Severe Fever With Thrombocytopenia Syndrome: A Report of Two Cases

Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne viral hemorrhagic fever caused by the severe fever with thrombocytopenia syndrome virus (SFTSV). This virus, which is transmitted through ticks, is prevalent in Asian countries, including Japan. This report describes two rare cases of SFTS with concurrent bacteremia. In the first case, a 73-year-old Japanese man presented with fever and coagulopathy and subsequently developed oral mucosal hemorrhage and bloody stools. Initial tests showed thrombocytopenia and leukopenia. Blood cultures on admission revealed Enterococcus faecalis bacteremia, and SFTSV co-infection was subsequently confirmed by polymerase chain reaction (PCR). He was treated with vancomycin, followed by ampicillin, and recovered. In the second case, a 70-year-old Japanese man presented with fever and diarrhea and subsequently developed renal impairment and thrombocytopenia. Blood cultures on admission revealed Escherichia coli bacteremia, and SFTSV co-infection was subsequently confirmed by PCR. He was treated with ceftriaxone, followed by ampicillin, and recovered. We conducted a literature search to look for evidence of a link between SFTS and bacteremia. Further epidemiological studies on the association between SFTS and bacteremia are warranted to provide an understanding of the pathogenic mechanisms.

Identification of Virulence Genes Associated with Pathogenicity of Translocating Escherichia coli with Special Reference to the Type 6 Secretion System

Recent genomic characterisation of translocating Escherichia coli HMLN-1 isolated from mesenteric lymph nodes (MLNs) and blood of a patient with a fatal case of pancreatitis revealed the presence of a type 6 secretion system (T6SS) that was not present in non-translocating E. coli strains. This strain was also genomically similar to adherent-invasive E. coli (AIEC) LF82 pathotype. We aimed to identify the role of T6SS-1 in the pathogenesis of this strain and other pathogenic E. coli. The HMLN-1 strain was initially tested for the presence of six virulence genes (VGs) associated with AIEC strains and an iron sequestering system. Additionally, HMLN-1's interaction with a co-culture of Caco-2:HT29-MTX cells and its intra-macrophagic survival was evaluated. We subsequently screened a collection of 319 pathogenic E. coli strains isolated from patients with urinary tract infection (UTI), diarrhoea, inflammatory bowel disease (IBD) and septicaemia for the presence of T6SS-1 and its expression related to adhesion, invasion and translocation via the above co-culture of the intestinal cell lines. The results showed that HMLN-1 harboured four of the AIEC-associated VGs (dsbA, htrA, ompC and afaC). Screening of the pathogenic E. coli collection detected the presence of the T6SS-1 genes in septicaemic and UTI E. coli strains at a significantly higher level than diarrhoea and IBD strains (p < 0.0001). The high expression of T6SS-1 in E. coli HMLN-1 upon adhesion and invasion, as well as its high prevalence among extra-intestinal E. coli strains, suggests a role for T6SS-1 in the pathogenesis of translocating E. coli.

Link between gut microbiota and neonatal sepsis

In neonates, the gastrointestinal tract is rapidly colonized by bacteria after birth. Gut microbiota development is critical during the first few years of life. However, disruption of gut microbiota development in neonates can lead to gut dysbiosis, characterized by overcolonization by pathogenic bacteria and delayed or failed maturation toward increasing microbial diversity and Fermicutes dominance. Gut dysbiosis can predispose infants to sepsis. Pathogenic bacteria can colonize the gut prior to sepsis and cause sepsis through translocation. This review explores gut microbiota development in neonates, the evidence linking gut dysbiosis to neonatal sepsis, and the potential role of probiotics in gut microbiota modulation and sepsis prevention.

Dynamic changes in the migratory microbial components of colon tissue during different periods of sepsis in an LPS-induced rat model

Previous studies have shown that bacterial translocation may play an important role in worsening gastrointestinal injury during sepsis. However, the dynamics of specific microbiota components in intestinal tissues at different sepsis stages remain unclear. Rats receiving intraperitoneal lipopolysaccharide (LPS) were sacrificed at 12 h and 48 h post-injection. Routine blood, serum cytokines, and microbiota in colon tissue, colonic contents, and lung tissue at different time points were assessed. Migratory microbial components in colonic tissue at 12 h and 48 h post-LPS were identified using source tracking, characteristic component identification, and abundance difference analyses. Colonic tissue microbiota changed dynamically over time after LPS injection, involving translocation of microbial components from colon contents and lung tissue at different time points. Bacteria migrating to colon tissue at 12 h sepsis were mainly from colonic contents, while those at 48 h were predominantly from the lung tissue. The migratory microbial components in colon tissue were widely associated with blood indicators and colonizing genus abundance and microbiota functionality in colon tissue. In this study, the temporal dynamics of bacterial translocation from various sources into colon tissues at different sepsis progression stages were characterized for the first time, and the species composition of these migrating microbes was delineated. These bacterial migrants may contribute to the pathophysiological processes in sepsis through direct interactions or indirectly by modulating colonic microbiota community structure and function.

A metagenomic prospective cohort study on gut microbiome composition and clinical infection in small bowel transplantation

Two-thirds of small-bowel transplantation (SBT) recipients develop bacteremia, with the majority of infections occurring within 3 months post-transplant. Sepsis-related mortality occurs in 31% of patients and is commonly caused by bacteria of gut origin, which are thought to translocate across the implanted organ. Serial post-transplant surveillance endoscopies provide an opportunity to study whether the composition of the ileal and colonic microbiota can predict the emergence as well as the pathogen of subsequent clinical infections in the SBT patient population. Five participants serially underwent aspiration of ileal and colonic bowel effluents at transplantation and during follow-up endoscopy either until death or for up to 3 months post-SBT. We performed whole-metagenome sequencing (WMS) of 40 bowel effluent samples and compared the results with clinical infection episodes. Microbiome composition was concordant between participants and timepoint-matched ileal and colonic samples. Four out of five (4/5) participants had clinically significant infections thought to be of gut origin. Bacterial translocation from the gut was observed in 3/5 patients with bacterial infectious etiologies. In all three cases, the pathogens had demonstrably colonized the gut between 1-10 days prior to invasive clinical infection. Recipients with better outcomes received donor grafts with higher alpha diversity. There was an increase in the number of antimicrobial resistance genes associated with longer hospital stay for all participants. This metagenomic study provides preliminary evidence to support the pathogen translocation hypothesis of gut-origin sepsis in the SBT cohort. Ileal and colonic microbiome compositions were concordant; therefore, fecal metagenomic analysis could be a useful surveillance tool for impeding infection with specific gut-residing pathogens.

Urinary tract infection is associated with 2.4-fold increased risk of surgical site infection in hip fracture surgery: systematic review and meta-analysis

BACKGROUND

There is no consensus regarding whether urinary tract infection (UTI) should be screened for or treated in hip fracture patients.

AIM

To assess the relationship between perioperative UTI and surgical site infection (SSI) in hip fracture patients, and the relationship between urinary catheterization and SSI in these patients.

METHODS

PubMed, Embase, CINAHL and Cochrane Library were searched to identify studies that evaluated the relationship between perioperative UTI and SSI and/or between urinary catheterization and SSI. Articles were included if they used the term UTI or specified UTI as symptomatic bacteriuria.

FINDINGS

A total of 4139 records were identified, with eight studies included. Meta-analysis of seven studies which evaluated perioperative UTI and SSI showed an SSI rate of 7.1% (95% confidence interval (CI): 3.8-13.2) among 1217 patients with UTI vs 2.4% (95% CI: 1.0-5.7) in 36,514 patients without UTI (OR: 2.41; 95% CI: 1.67-3.46; P < 0.001). In three studies which specifically defined UTI as symptomatic bacteriuria, the SSI rate among UTI patients was 5.7% (95% CI: 4.0-8.1) vs 1.1% (95% CI: 0.2-5.2) in those without UTI (OR: 3.00; 95% CI: 0.55-16.26; P = 0.20). One study evaluated urinary catheterization and SSI.

CONCLUSION

Perioperative UTI is associated with a higher risk of SSI among hip fracture patients but the evidence is limited by the heterogeneity in the definition of UTI. We recommend considering the possibility of perioperative UTI in hip fracture patients, with treatment administered as necessary to reduce SSI rates.

YuPingFengSan ameliorates LPS-induced acute lung injury and gut barrier dysfunction in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Yupingfengsan (YPFS) is a traditional Chinese medicine decoction. YPFS comprises Astragalus mongholicus Bunge (Huangqi), Atractylodes rubra Dekker (Baizhu), and Saposhnikovia divaricata (Turcz.ex Ledeb.) Schischk (Fangfeng). YPFS is commonly used to treat chronic obstructive pulmonary disease, asthma, respiratory infections, and pneumonia, but the mechanism of action remains unclear.

AIM OF THE STUDY

Acute lung injury (ALI) and its severe form of acute respiratory distress syndrome (ARDS) cause morbidity and mortality in critical patients. YPFS is a commonly used herbal soup to treat respiratory and immune system diseases. Nevertheless, the effect of YPFS on ALI remains unclear. This study aimed to investigate the effect of YPFS on lipopolysaccharide (LPS)-induced ALI in mice and elucidate its potential molecular mechanisms.

MATERIALS AND METHODS

The major components of YPFS were detected by High-performance liquid chromatography (HPLC). C57BL/6J mice were given YPFS for seven days and then treated with LPS. IL-1β, IL-6, TNF-α, IL-8, iNOS, NLRP3, PPARγ, HO-1, ZO-1, Occludin, Claudin-1, AQP3, AQP4, AQP5, ENaCα, ENaCβ, EnaCγ mRNA in lung and ZO-1, Occludin, Claudin-1, AQP3, AQP4, AQP5, ENaCα, ENaCβ, and EnaCγ mRNA in colon tissues were measured by Real-Time Quantitative PCR (RT-qPCR). The expressions of TLR4, MyD88, NOD-like receptor thermal protein domain associated protein 3 (NLRP3), ASC, MAPK signaling pathway, Nrf2, and HO-1 in the lung were detected by Western blot. Plasma inflammatory factors Interleukin (IL)-1β, IL-6, and Tumor Necrosis Factor-α (TNF-α) were determined by Enzyme-linked Immunosorbent Assay (ELISA). Lung tissues were processed for H & E staining, and colon tissues for HE, WGA-FITC, and Alcian Blue staining.

RESULTS

The results showed that YPFS administration alleviated lung injury and suppressed the production of inflammatory factors, including IL-1β, IL-6, and TNF-α. Additionally, YPFS reduced pulmonary edema by promoting the expressions of aquaporin and sodium channel-related genes (AQP3, AQP4, AQP5, ENaCα, ENaCβ, and EnaCγ). Further, YPFS intervention exhibited a therapeutic effect on ALI by inhibiting the activation of the NLRP3 inflammasome and MAPK signaling pathways. Finally, YPFS improved gut barrier integrity and suppressed intestinal inflammation in LPS-challenged mice.

CONCLUSIONS

YPFS protected mice against LPS-induced ALI by attenuating lung and intestinal tissue damage. This study sheds light on the potential application of YPFS to treat ALI/ARDS.

Colorectal Cancer-The "Parent" of Low Bowel Obstruction

Introduction: Despite the improvement of early diagnosis methods for multiple pathological entities belonging to the digestive tract, bowel obstruction determined by multiple etiologies represents an important percentage of surgical emergencies. General data: Although sometimes obstructive episodes are possible in the early stages of colorectal cancer, the most commonly installed intestinal obstruction has the significance of an advanced evolutionary stage of neoplastic disease. Development of Obstructive Mechanism: The spontaneous evolution of colorectal cancer is always burdened by complications. The most common complication is low bowel obstruction, found in approximately 20% of the cases of colorectal cancer, and it can occur either relatively abruptly, or is preceded by initially discrete premonitory symptoms, non-specific (until advanced evolutionary stages) and generally neglected or incorrectly interpreted. Success in the complex treatment of a low neoplastic obstruction is conditioned by a complete diagnosis, adequate pre-operative preparation, a surgical act adapted to the case (in one, two or three successive stages), and dynamic postoperative care. The moment of surgery should be chosen with great care and is the result of the experience of the anesthetic-surgical team. The operative act must be adapted to the case and has as its main objective the resolution of intestinal obstruction and only in a secondary way the resolution of the generating disease. Conclusions: The therapeutic measures adopted (medical-surgical) must have a dynamic character in accordance with the particular situation of the patient. Except for certain or probably benign etiologies, the possibility of colorectal neoplasia should always be considered, in low obstructions, regardless of the patient's age.

The in Vitro Fermentation of Cordyceps militaris Polysaccharides Changed the Simulated Gut Condition and Influenced Gut Bacterial Motility and Translocation

The motility ability of intestinal lipopolysaccharide (LPS)-producing bacteria determines their translocation to the enterohepatic circulation and works as an infectious complication. In this study, the health effects of Cordyceps militaris polysaccharides (CMPs) were re-evaluated based on whether these polysaccharides could affect the motility of gut commensal LPS-producing bacteria and impede their translocation. The results showed that CMP-m fermentation in the gut could change the chemical environment, leading to a decrease in velocity and a shift in the motility pattern. Further study suggested that detachment/fragmentation of flagella, decreased motor forces, and changed chemical conditions might account for this weakened motility. The adhesion and invasion abilities of gut bacteria were also reduced, with lower expression of virulence-related genes. These results indicated that the health regulation effects of CMP-m might be through decreasing the motility of LPS-producing bacteria, hindering their translocation and therefore reducing the LPS level in the enterohepatic circulation.

Effects of Different Routes and Forms of Vitamin D Administration on Mesenteric Lymph Node CD4+ T Cell Polarization and Intestinal Injury in Obese Mice Complicated with Polymicrobial Sepsis

This study compared the efficacies of enteral cholecalciferol and/or intravenous (IV) calcitriol administration on mesenteric lymph node (MLN) cluster-of-differentiation-4-positive (CD4+) T cell distribution and intestinal barrier damage in obese mice complicated with sepsis. Mice were fed a high-fat diet for 16 weeks and then sepsis was induced by cecal ligation and puncture (CLP). Mice were divided into the following sepsis groups: without vitamin D (VD) (S); with oral cholecalciferol 1 day before CLP (G); with IV calcitriol 1 h after CLP (V); and with both cholecalciferol before and IV calcitriol after CLP (GV). All mice were sacrificed at 12 or 24 h after CLP. The findings show that the S group had a higher T helper (Th)17 percentage than the VD-treated groups at 12 h after CLP. The V group exhibited a higher Th1 percentage and Th1/Th2 ratio than the other groups at 24 h, whereas the V and GV groups had a lower Th17/regulatory T (Treg) ratio 12 h post-CLP in MLNs. In ileum tissues, the VD-treated groups had higher tight junction protein and cathelicidin levels, and higher mucin gene expression than the S group at 24 h post-CLP. Also, aryl hydrocarbon receptor (AhR) and its associated cytochrome P450 1A1 and interleukin 22 gene expressions were upregulated. In contrast, levels of lipid peroxides and inflammatory mediators in ileum tissues were lower in the groups with VD treatment after CLP. These results suggest that IV calcitriol seemed to have a more-pronounced effect on modulating the homeostasis of Th/Treg subsets in MLNs. Both oral cholecalciferol before and IV calcitriol after CLP promoted cathelicidin secretion, alleviated intestinal inflammation, and ameliorated the epithelial integrity in obese mice complicated with sepsis possibly via VD receptor and AhR signaling pathways.

Maternal gut microbiome-induced IgG regulates neonatal gut microbiome and immunity

The gut microbiome elicits antigen-specific immunoglobulin G (IgG) at steady state that cross-reacts to pathogens to confer protection against systemic infection. The role of gut microbiome-specific IgG antibodies in the development of the gut microbiome and immunity against enteric pathogens in early life, however, remains largely undefined. In this study, we show that gut microbiome-induced maternal IgG is transferred to the neonatal intestine through maternal milk via the neonatal Fc receptor and directly inhibits Citrobacter rodentium colonization and attachment to the mucosa. Enhanced neonatal immunity against oral C. rodentium infection was observed after maternal immunization with a gut microbiome-derived IgG antigen, outer membrane protein A, or induction of IgG-inducing gut bacteria. Furthermore, by generating a gene-targeted mouse model with complete IgG deficiency, we demonstrate that IgG knockout neonates are more susceptible to C. rodentium infection and exhibit alterations of the gut microbiome that promote differentiation of interleukin-17A-producing γδ T cells in the intestine, which persist into adulthood and contribute to increased disease severity in a dextran sulfate sodium-induced mouse model of colitis. Together, our studies have defined a critical role for maternal gut microbiome-specific IgG antibodies in promoting immunity against enteric pathogens and shaping the development of the gut microbiome and immune cells in early life.

Probiotics and synbiotics for preventing postoperative infectious complications in colorectal cancer patients: a systematic review and meta-analysis

BACKGROUND

The health benefits of probiotics and synbiotics in healthy adults are well established, but their role in preventing infectious complications after surgery for colorectal cancer remains controversial. The aim of this meta-analysis was to assess the impact of probiotics/synbiotics on the incidence of infectious complications in patients who had surgery for colorectal cancer.

METHODS

A comprehensive literature search of all randomized control trials (RCTs) was conducted using PubMed, Embase, World Health Organization (WHO) Global Index Medicus, WHO clinical trial registry, and Clinicaltrials.gov. Inclusion criteria included RCTs comparing the use of any strain or dose of a specified probiotic/synbiotic with placebo or a "standard care" control group. The incidence of postoperative infectious complications was analyzed.

RESULTS

Fourteen RCTs involving 1566 patients (502 receiving probiotics, 273 receiving synbiotics, and 791 receiving placebo) were analyzed. Overall, probiotic or synbiotic administration significantly reduced the risk of developing postoperative infectious complications by 37% (relative risk (RR) = 0.63, 95% confidence interval (CI) 0.54-0.74, p < 0.001). Furthermore, when considering the six different types of postoperative infectious complications (septicemia, incision infection, central line infection, pneumonia infection, urinary infection, and incidence of diarrhea), probiotic or synbiotic administration was beneficial in reducing the incidence of each one of them. The quality of evidence was listed below: incidence of diarrhea (high), septicemia (moderate), incision infection (moderate), pneumonia infection (moderate), urinary infection (moderate), and central line infection (low). However, for the main outcome of infectious complications, we found evidence of possible publication bias, although estimates still showed a reduction following trim-and-fill analysis (RR = 0.72, 95% CI 0.62-0.84, p < 0.001).

CONCLUSIONS

The use of probiotic/synbiotic supplementation is associated with a significant reduction in the risk of developing postoperative infectious complications in patients who had surgery for colorectal cancer. Additional studies are needed to confirm the findings due to publication bias and low quality of evidence.

The role of bacterial translocation in sepsis: a new target for therapy

Sepsis is a leading cause of death in critically ill patients, primarily due to multiple organ failures. It is associated with a systemic inflammatory response that plays a role in the pathogenesis of the disease. Intestinal barrier dysfunction and bacterial translocation (BT) play pivotal roles in the pathogenesis of sepsis and associated organ failure. In this review, we describe recent advances in understanding the mechanisms by which the gut microbiome and BT contribute to the pathogenesis of sepsis. We also discuss several potential treatment modalities that target the microbiome as therapeutic tools for patients with sepsis.

Gut barrier disruption and chronic disease

The intestinal barrier protects the host against gut microbes, food antigens, and toxins present in the gastrointestinal tract. However, gut barrier integrity can be affected by intrinsic and extrinsic factors, including genetic predisposition, the Western diet, antibiotics, alcohol, circadian rhythm disruption, psychological stress, and aging. Chronic disruption of the gut barrier can lead to translocation of microbial components into the body, producing systemic, low-grade inflammation. While the association between gut barrier integrity and inflammation in intestinal diseases is well established, we review here recent studies indicating that the gut barrier and microbiota dysbiosis may contribute to the development of metabolic, autoimmune, and aging-related disorders. Emerging interventions to improve gut barrier integrity and microbiota composition are also described.

Acute Variceal Bleed in Cirrhosis is Associated With Reversible Changes in Tight Junction Protein Expression in the Intestine: A Proof-of-Concept Study

BACKGROUND

Tight junction proteins (TJPs) play an important role in gut-barrier dysfunction in cirrhosis and its complications such as acute variceal bleed (AVB). However, the dynamics of TJPs expression after AVB, its relation to bacterial translocation, and impact on clinical outcome is largely unknown.

AIMS

The aim of this study was to study the expression of TJPs in cirrhosis and assess its dynamic changes in AVB. In addition, the relation of TJP expression to endotoxemia and clinical outcomes was assessed.

METHODS

In this prospective pilot study, 17 patients of cirrhosis with AVB, 59 patients of cirrhosis without AVB (non-AVB cirrhosis), and 20 controls were assessed for claudin-2 and claudin-4 expression in the duodenal biopsy. In the AVB-cirrhosis group, additional biopsies were obtained after 3 weeks. Endotoxemia was assessed by measuring IgG anti-endotoxin antibody levels. Claudin expression was correlated with a 6-month survival.

RESULTS

Claudin-2 expression was downregulated in patients with AVB and non-AVB cirrhosis in villi (P < 0.001 and 0.013) and crypts (P < 0.001 and 0.012), respectively, compared with the controls. Claudin-4 expression was similar in villi (P = 0.079), but lower in crypts (P = 0.007) in patients with cirrhosis. Claudin-2 expression was upregulated on serial biopsies in both villi and crypts (P = 0.003 and 0.001, respectively) in AVB-cirrhosis with postbleed expression comparable with those with non-AVB cirrhosis. IgG anti-endotoxin antibody levels were elevated in cirrhosis with no correlation with claudin-2/4 expression. Claudin-2 expression independently predicted survival at 6 months.

CONCLUSION

Both claudin-2 and claudin-4 expression are downregulated in cirrhosis. AVB is associated with dynamic changes in TJPs expression. Gut-barrier dysfunction might predict outcomes independent of bacterial endotoxemia in cirrhosis.

Demonstration of Gut-Barrier Dysfunction in Early Stages of Non-alcoholic Fatty Liver Disease: A Proof-Of-Concept Study

BACKGROUND/AIMS

Gut-barrier dysfunction is well recognized in pathogenesis of both non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD). However, comparison of components of this dysfunction between the two etiologies remains unexplored especially in early stages of NAFLD.

METHODS

Components of gut-barrier dysfunction like alterations in intestinal permeability (IP) by lactulose mannitol ratio (LMR) in urine, systemic endotoxemia (IgG and IgM anti-endotoxin antibodies), systemic inflammation (serum tumor necrosis factor alpha [TNF-α] and interleukin-1 [IL-1] levels), tight junction (TJ) proteins expression in duodenal biopsy and stool microbiota composition using Oxford Nanopore MinION device were prospectively evaluated in patients with NAFLD (n = 34) with no cirrhosis, ALD (n = 28) and were compared with disease free controls (n = 20).

RESULTS

Patients with ALD had more advanced disease than those with NAFLD (median liver stiffness -NAFLD:7.1 kPa [5.9-8.9] vs. ALD:14.3 kPa [9.6-24], P < 0.001]. Median LMR was significantly higher in NAFLD and ALD group when compared to controls (NAFLD 0.054 [0.037-0.17] vs. controls 0.027 [0.021-0.045] (P = 0.001)) and ALD 0.043 [0.03-0.068] vs. controls 0.027 [0.021-0.045] (P = 0.019)]. Anti-endotoxin antibody titer (IgM) (MMU/mL) was lowest in NAFLD 72.9 [3.2-1089.5] compared to ALD 120.6 [20.1-728]) (P = 0.042) and controls 155.3 [23.8-442.9]) (P = 0.021). Median TNF-α (pg/mL) levels were elevated in patients with NAFLD (53.3 [24.5-115]) compared to controls (16.1 [10.8-33.3]) (P < 0.001) and ALD (12.3 [10.1-42.7]) (P < 0.001). Expression of zonulin-1 and claudin-3 in duodenal mucosa was lowest in NAFLD. On principal co-ordinate analysis (PCoA), the global bacterial composition was significantly different across the three groups (PERMANOVA test, P < 0.001).

CONCLUSION

While remaining activated in both etiologies, gut-barrier dysfunction abnormalities were more pronounced in NAFLD at early stages compared to ALD despite more advanced disease in the latter.

Intravenous calcitriol administration modulates mesenteric lymph node CD4+ T-cell polarization and attenuates intestinal inflammation in obese mice complicated with polymicrobial sepsis

BACKGROUND

Sepsis is a lethal syndrome with T-cell dysregulation, imbalanced inflammatory reactions, and gastrointestinal dysfunction. Obesity coexistent with sepsis can cause more-deleterious disease outcomes. Vitamin D is a nutrient with immunomodulatory ability and helps maintain intestinal homeostasis. This study investigated treatment with calcitriol on mesenteric lymph node (MLN) CD4⁺ T-cell polarization and intestinal injury in obese mice with sepsis.

METHODS

Mice received a high-fat diet for 10 weeks; then, mice were separated into an obese control group without sepsis and sepsis groups that underwent cecal ligation and puncture (CLP). Septic mice were subdivided into a group that was injected with saline (SS group) or a group that was injected with calcitriol (SD group) via a tail vein 1 h after CLP. Obese mice with sepsis were euthanized at 12 or 24 h post CLP.

RESULTS

Sepsis resulted in increased percentages of type 2 T helper (Th2), Th17, and regulatory T (Treg) cells in MLNs. Also, inflammation-associated genes were upregulated and tight junction genes downregulated in the intestines after CLP. Compared with the SS group, the SD group exhibited reduced Th2, Th17, and Treg percentages in MLNs. Also, intestinal inflammatory chemokine expressions were reduced, whereas MUC2, ZO-1, and occludin had increased after CLP. Lower inflammatory cytokine levels in peritoneal lavage fluid in the ileum were also noted in the SD group.

CONCLUSIONS

Intravenous calcitriol treatment after sepsis can elicit more-balanced CD4 T-cell subsets in lymph nodes near the intestines and alleviate intestinal inflammation and injury in obese mice complicated with sepsis.

Probiotic Bacterial Application in Pediatric Critical Illness as Coadjuvants of Therapy

The use of probiotics in critically ill adult and children patients has been growing exponentially over the last 20 years. Numerous factors in pediatriac intensive care unit (PICU) patients may contribute to intestinal dysbiosis, which subsequently promotes the pathobiota's growth. Currently, lactobacillus and bifidobacterium species are mainly used to prevent the development of systemic diseases due to the subverted microbiome, followed by streptococcus, enterococcus, propionibacterium, bacillus and Escherichia coli, Lactobacillus rhamnosus GG, and Lactobacillus reuteri DSM 17938. The aim of this article is to review the scientific literature for further confirmation of the importance of the usage of probiotics in intensive care unit (ICU) patients, especially in the pediatric population. A progressive increase in nosocomial infections, especially nosocomial bloodstream infections, has been observed over the last 30 years. The World Health Organization (WHO) reported that the incidence of nosocomial infections in PICUs was still high and ranged between 5% and 10%. Petrof et al. was one of the first to demonstrate the efficacy of probiotics for preventing systemic diseases in ICU patients. Recently, however, the use of probiotics with different lactobacillus spp. has been shown to cause a decrease of pro-inflammatory cytokines and an increase in anti-inflammatory cytokines. In addition, in some studies, the use of probiotics, in particular the mix of Lactobacillus and Bifidobacterium reduces the incidence of ventilator-associated pneumonia (VAP) in PICU patients requiring mechanical ventilation. In abdominal infections, there is no doubt at all about the usefulness of using Lactobacillus spp probiotics, which help to treat ICU-acquired diarrhoea episodes as well as in positive blood culture for candida spp. Despite the importance of using probiotics being supported by various studies, their use is not yet part of the standard protocols to which all doctors must adhere. In the meantime, while waiting for protocols to be drawn up as soon as possible for use in PICUs, routine use could certainly stimulate the intestine's immune defences. Though it is still too early to say, they could be considered the drugs of the future.

Characterization of the blood and neutrophil-specific microbiomes and exploration of potential bacterial biomarkers for sepsis in surgical patients

Introduction

Recent studies have demonstrated the presence of a circulating microbiome in the blood of healthy subjects and chronic inflammatory patients. However, our knowledge regarding the blood microbiome and its potential roles in surgical patients remains very limited. The objective of this study was to determine the blood microbial landscape in surgical patients and to explore its potential associations with postoperative sepsis.

Materials and Methods

2825 patients who underwent surgical treatments were screened for enrollment and 204 cases were recruited in this study. The patients were sub‐grouped into noninfected, infected, sepsis, and septic shock according to postoperative clinical manifestations. A total of 222 blood samples were obtained for neutrophil isolation, DNA extraction and high‐throughput sequencing, quantitative proteomics analysis, and flow cytometric analyses.

Results

Blood and neutrophils in surgical patients and healthy controls contained highly diverse microbiomes, mainly comprising Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes. The majority (80.7%–91.5%) of the microbiomes were composed of gut‐associated bacteria. The microbiomes in septic patients were significantly distinct from those of healthy controls, and marked differences in microbiome composition were observed between sepsis and septic shock groups. Several specific bacterial genera, including Flavobacterium, Agrococcus, Polynucleobacter, and Acidovorax, could distinguish patients with septic shock from those with sepsis, with higher area under curve values. Moreover, Agrococcus, Polynucleobacter, and Acidovorax were positively associated with the sequential (sepsis‐related) organ failure assessment scores and/or acute physiology and chronic health examination scores in septic shock patients. The proteins involved in bactericidal activities of neutrophils were downregulated in septic patients.

Conclusions

We present evidence identifying significant changes of blood and neutrophil‐specific microbiomes across various stages of sepsis, which might be associated with the progression of sepsis after surgical treatments. Several certain bacterial genera in blood microbiome could have potential as microbial markers for early detection of sepsis.

Intravenous calcitriol administration regulates the renin-angiotensin system and attenuates acute lung injury in obese mice complicated with polymicrobial sepsis

Calcitriol, an active form of vitamin D, has immunomodulatory and anti-inflammatory properties. Vitamin D levels have inverse correlation with sepsis outcomes and obesity may aggravate the severity of the diseases. This study administered calcitriol to investigate its impact on sepsis-induced acute lung injury (ALI) in obese mice. Mice were fed a high-fat diet to induce obesity and were randomly assigned to control or sepsis groups, which were intravenously administered either saline (SS) or calcitriol (SD). Sepsis was induced by cecal ligation and puncture (CLP). Saline or calcitriol was injected 1 h after CLP via tail vein. Mice were sacrificed at either 12 or 24 h post-CLP and survival rates were observed. The results demonstrated that sepsis caused upregulation of inflammatory mediators and downregulation of renin-angiotensin system (RAS)-associated gene expressions in the lungs of obese mice. Cluster of differentiation 68 (CD68) expression and myeloperoxidase (MPO) activities also increased. Calcitriol treatment lowered expressions of blood and lung inflammatory mediators at 12 and/or 24 h after CLP. The RAS-proinflammatory-associated angiotensin type 1 receptor (AT1R) was lower while anti-inflammatory Mas receptor and AT2R expressions were higher at 12 h after CLP than those in the SS group. In addition, the SD group exhibited lower CD68 expression and MPO activity. Lower lung injury scores and higher survival rates were also noted in the SD group. The findings suggest that calcitriol treatment after sepsis induction upregulated RAS-associated anti-inflammatory pathway and decreased immune cell infiltration, which may have alleviated the severity of ALI of obese mice.

Risk Factors Associated With Postendoscopic Mucosal Resection Bleeding in Patients With Cirrhosis: A Retrospective Multicenter Cohort Study

BACKGROUND AND AIM

There is limited data regarding the safety of endoscopic mucosal resection (EMR) in the cirrhotic population. Our study aimed to evaluate the safety of colonoscopic EMR in cirrhosis.

MATERIALS AND METHODS

This was a retrospective review of cirrhotics who underwent colonic EMR at 8 Cleveland Clinic Centers between January 1, 2006, and December 31, 2018. Patient data including polyp details and complications occurring within 30 days of the procedure were noted. Univariable and multivariable logistic regression analyses were conducted to find risk factors for post-EMR bleeding.

RESULTS

A total of 238 patients who underwent EMR were included. There were 145 males (60.9%) and the mean age was 61.9±8.6 years. Immediate and delayed bleeding, and postpolypectomy syndrome rates were 9.2%, 5.8%, and 1.3%, respectively. Significant risk factors for postpolypectomy bleeding were: increased age (P=0.001), procedure duration >37 minutes (P=0.001), antiplatelet use within 5 days (P=0.023), and lesion diameter >15 mm (P=0.004). Multivariable analysis revealed independent predictors of procedure-related bleeding: age above 65 years [odds ratio (OR) 2.14, P=0.044], antiplatelet use within 5 days (OR 2.42, P=0.047), right colon polyp (OR 3.51, P=0.001), and lesion diameter >15 mm (OR 3.22, P=0.003).

CONCLUSIONS

EMR in cirrhotics has an acceptable bleeding risk. Age above 65 years, right colon polyp, polyp size >15 mm, and use of antiplatelets within 5 days are independent risk factors for bleeding.

Gut Microbiota Dysbiosis as a Target for Improved Post-Surgical Outcomes and Improved Patient Care: A Review of Current Literature

Critical illness results in significant changes in the human gut microbiota, leading to the breakdown of the intestinal barrier function, which plays a role in the pathogenesis of multiple organ dysfunction. Patients with sepsis/acute respiratory distress syndrome (ARDS) have a profoundly distorted intestinal microbiota rhythm, which plays a considerable role in the development of gut-derived infections and intestinal dysbiosis. Despite recent medical developments, postsurgical complications are associated with a high morbidity and mortality rate. Bacterial translocation, which is the movement of bacteria and bacterial products across the intestinal barrier, was shown to be a mechanism behind sepsis. Current research is focusing on a solution by addressing significant factors that contribute to intestinal dysbiosis, which subsequently leads to multiple organ failure and, thus, mortality. It may, however, be challenging to manipulate the microbiota in critically ill patients for enhanced therapeutic gain. Probiotic manipulation is advantageous for maintaining the gut-barrier defense and for modulating the immune response. Based on available published research, this review aims to address the application of potential strategies in the intensive care unit, supplemented with current therapeutics by the administration of probiotics, prebiotics, and fecal microbiota transplant, to reduce post-surgical complications of sepsis/ARDS in critically ill patients.

The positive effect of eugenol on acute pancreatic tissue injury: a rat experimental model

Introduction

we present a rat experimental model used to evaluate the possible reduction in the extent of pancreatic tissue injury in acute pancreatitis cases, after administration of eugenol.

Methods

one hundred and twenty Wistar rats were used, which were randomly assigned in 3 groups: sham (n=20), control (n=50) and eugenol (n=50). Acute pancreatitis was induced by biliopancreatic ligation in the control and eugenol groups, but not in the Sham group. In the eugenol group, eugenol was administered per-os. Five histopathological parameters, such as edema, inflammatory infiltration, duct dilatation, hemorrhage and acinar necrosis were evaluated.

Results

at 72 h from acute pancreatitis induction, the total histological score was diminished in the eugenol group (p<0.0005) and duct dilatation and inflammatory infiltration were reduced compared to the control group (p<0.05). In addition, at 72 h, eugenol reduced pancreatic myeloperoxidase activity (p<0.0005).

Conclusion

eugenol, a highly free radical scavenger agent, may have a preventive role in acute pancreatic injury, as it was evident in our rat experimental model.

Intake of Lactobacillus delbrueckii (pExu:hsp65) Prevents the Inflammation and the Disorganization of the Intestinal Mucosa in a Mouse Model of Mucositis

5-Fluorouracil (5-FU) is an antineoplastic drug that causes, as a side effect, intestinal mucositis, acute inflammation in the small bowel. The Heat Shock Protein (Hsp) are highly expressed in inflammatory conditions, developing an important role in immune modulation. Thus, they are potential candidates for the treatment of inflammatory diseases. In the mucositis mouse model, the present study aimed to evaluate the beneficial effect of oral administration of milk fermented by Lactobacillus delbrueckii CIDCA 133 (pExu:hsp65), a recombinant strain. This approach showed increased levels of sIgA in the intestinal fluid, reducing inflammatory infiltrate and intestinal permeability. Additionally, the histological score was improved. Protection was associated with a reduction in the gene expression of pro-inflammatory cytokines such as Tnf, Il6, Il12, and Il1b, and an increase in Il10, Muc2, and claudin 1 (Cldn1) and 2 (Cldn2) gene expression in ileum tissue. These findings are corroborated with the increased number of goblet cells, the electronic microscopy images, and the reduction of intestinal permeability. The administration of milk fermented by this recombinant probiotic strain was also able to reverse the high levels of gene expression of Tlrs caused by the 5-FU. Thus, the rCIDCA 133:Hsp65 strain was revealed to be a promising preventive strategy for small bowel inflammation.

Altered intestinal microflora and barrier injury in severe acute pancreatitis can be changed by zinc

To investigate the effect of zinc (Zn) supplementation on intestinal microflora changes and bacterial translocation in rats with severe acute pancreatitis (SAP), the rats were divided into the sham surgery (SS), SAP, SS + Zn, and SAP + Zn groups. Saline (0.1 mL/100g) and 5% sodium taurocholate were injected into the pancreaticobiliary duct of the rats in the SS and SAP + Zn groups, respectively. Intraperitoneal injection of 5 mg/kg Zn was performed immediately after injecting saline or 5% sodium taurocholate into the rats in both groups. Serum amylase and Zn levels, plasma endogenous endotoxin, intestinal permeability, and the positive rate of intestinal bacterial translocation were detected, haematoxylin and eosin (H&E) staining was performed, and the pancreatic tissue scores were calculated for each group. In addition, immunohistochemical (IHC) staining was performed to evaluate the expression of IL-1β and TNF-α. Real-time fluorescence quantitative PCR was used to quantify the gene copy numbers of Escherichia, Bifidobacterium, and Lactobacillus in the cecum. The levels of amylase and plasma endotoxin in the SAP group were significantly higher than those in the SS and SS + Zn groups. Intestinal mucosal permeability and intestinal bacterial translocation in the liver, pancreas, and mesenteric lymph nodes were increased in the SAP group. However, the levels of amylase and plasma endotoxin were decreased as a result of zinc supplementation in the SAP group. The expression of IL-1β and TNF-α was also reduced to a greater degree in the SAP + Zn group than in the SAP group. Moreover, alleviated intestinal mucosal permeability and intestinal bacterial translocation in the liver, pancreas, and mesenteric lymph nodes were found in the SAP + Zn group. The results of real-time quantitative PCR showed that the gene copy number of Escherichia increased with time, and the gene copy numbers of Lactobacillus and Bifidobacterium decreased over time. Zn supplementation prevented the release of TNF-α and IL-1β, alleviated intestinal permeability and endotoxemia, reduced bacterial translocation, and inhibited changes in pathogenic intestinal flora in rats with SAP.

The Role of the Microbiome in Oral Squamous Cell Carcinoma with Insight into the Microbiome-Treatment Axis

Oral squamous cell carcinoma (OSCC) is one of the leading presentations of head and neck cancer (HNC). The first part of this review will describe the highlights of the oral microbiome in health and normal development while demonstrating how both the oral and gut microbiome can map OSCC development, progression, treatment and the potential side effects associated with its management. We then scope the dynamics of the various microorganisms of the oral cavity, including bacteria, mycoplasma, fungi, archaea and viruses, and describe the characteristic roles they may play in OSCC development. We also highlight how the human immunodeficiency viruses (HIV) may impinge on the host microbiome and increase the burden of oral premalignant lesions and OSCC in patients with HIV. Finally, we summarise current insights into the microbiome–treatment axis pertaining to OSCC, and show how the microbiome is affected by radiotherapy, chemotherapy, immunotherapy and also how these therapies are affected by the state of the microbiome, potentially determining the success or failure of some of these treatments.

Drain site enterocutaneous fistula after hyperthermic intraperitoneal chemotherapy

Spontaneous sigmoid colon perforation after cytoreduction surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) is a rare complication. It is more commonly seen with mitomycin‐based HIPEC. This case study's patient presented with pus discharge at the drain site after 4 weeks of surgery. The symptoms persisted after conservative treatment. High suspicion after the feculent smell of the discharge fluidled to the prompt diagnosis of enterocutaneous fistula. There was limitedperforation with abscess formation, followed by fistula formation. The patient was treated successfully with surgery.

The magnitude of physical exercise-induced hyperthermia is associated with changes in the intestinal permeability and expression of tight junction genes in rats

We investigated whether the magnitude of exercise-induced hyperthermia influences intestinal permeability and tight junction gene expression. Twenty-nine male Wistar rats were divided into four groups: rest at 24 °C and exercise at 13 °C, 24 °C or 31 °C. The exercise consisted of a 90-min treadmill run at 15 m/min, and different ambient temperatures were used to produce distinct levels of exercise-induced hyperthermia. Before the experimental trials, the rats were treated by gavage with diethylenetriaminepentaacetic acid labeled with technetium-99 metastable as a radioactive probe. The rats' core body temperature (T_CORE) was measured by telemetry. Immediately after the trials, the rats were euthanized, and the intestinal permeability was assessed by measuring the radioactivity of blood samples. The mRNA levels of occludin and zonula occludens-1 (ZO-1) genes were determined in duodenum samples. Exercise at 24 °C increased T_CORE to values close to 39 °C, without changing permeability compared with the resting trial at the same environment. Meanwhile, rats' T_CORE exceeded 40 °C during exercise at 31 °C, leading to greater permeability relative to those observed after exercise in the other ambient temperatures (e.g., 0.0037%/g at 31 °C vs. 0.0005%/g at 13 °C; data expressed as medians; p < 0.05). Likewise, the rats exercised at 31 °C exhibited higher mRNA levels of ZO-1 and occludin genes than the rats exercised at 24 °C or 13 °C. The changes in permeability and gene expression were positively and significantly associated with the magnitude of hyperthermia. We conclude that marked hyperthermia caused by exercise in the warmer environment increases intestinal permeability and mRNA levels of tight junction genes.

Follow-up blood cultures in Gram-negative bacilli bacteremia: are they needed for critically ill patients?

BACKGROUND

Gram-negative bacilli bacteremias (GNB-Bs) represent a major cause of morbidity and mortality in Intensive Care Unit (ICU) patients. Aim of this study was to investigate the role of follow-up blood cultures (FUBCs) and the clinical significance of persistent bacteremia (PB) in these settings.

METHODS

We retrospectively analyzed clinical data and outcome of GNB-Bs that occurred in ICU patients over a span of 1 year. In particular we sought information on development and clinical details of PB, defined as repeatedly positive FUBCs after ≥96 hours of appropriate antibiotic treatment and ≥48 hours after removal of endovascular devices.

RESULTS

Among 307 ICU patients, 69 (22.4%) developed 107 GNB-Bs. Of these, 78 (73%) could be eventually analyzed: 50 of 78 (64.1%) were non-PBs from 26 patients and 28 of 78 (35.9%) were PBs from 23 patients. Duration of fever and bacteremia, time to procalcitonin normalization and weaning from vasopressors were longer in episodes of PBs than non-PBs (P=0.04, P<0.001, P=0.02 and P=0.004, respectively). Primary bacteremia was more frequent in non-PBs than in PBs (29 of 50, 58% vs. 3/28, 10.7%, P=0.0001), whereas septic thrombus infection (STI) was the source of infection in 14 of 28 (50%). Finally, clinical features and 30-day mortality did not differ between patients with PB and those who developed only non-PB episodes.

CONCLUSIONS

Among our ICU patients, more than one third of GNB-Bs for which FUBCs were performed resulted PB. This condition is often associated with the presence of STI; therefore, FUBCs seem useful for the optimal management of GNB in this clinical setting.

Cathelicidin preserves intestinal barrier function in polymicrobial sepsis

Objectives

The intestinal epithelium compartmentalizes the sterile bloodstream and the commensal bacteria in the gut. Accumulating evidence suggests that this barrier is impaired in sepsis, aggravating systemic inflammation. Previous studies reported that cathelicidin is differentially expressed in various tissues in sepsis. However, its role in sepsis-induced intestinal barrier dysfunction has not been investigated.

Design

To examine the role of cathelicidin in polymicrobial sepsis, cathelicidin wild-(Cnlp^+/+) and knockout (Cnlp^−/−) mice underwent cecal-ligation and puncture (CLP) followed by the assessment of septic mortality and morbidity as well as histological, biochemical, immunological, and transcriptomic analyses in the ileal tissues. We also evaluated the prophylactic and therapeutic efficacies of vitamin D3 (an inducer of endogenous cathelicidin) in the CLP-induced murine polymicrobial sepsis model.

Results

The ileal expression of cathelicidin was increased by three-fold after CLP, peaking at 4 h. Knockout of Cnlp significantly increased 7-day mortality and was associated with a higher murine sepsis score. Alcian-blue staining revealed a reduced number of mucin-positive goblet cells, accompanied by reduced mucin expression. Increased number of apoptotic cells and cleavage of caspase-3 were observed. Cnlp deletion increased intestinal permeability to 4kD fluorescein-labeled dextran and reduced the expression of tight junction proteins claudin-1 and occludin. Notably, circulating bacterial DNA load increased more than two-fold. Transcriptome analysis revealed upregulation of cytokine/inflammatory pathway. Depletion of Cnlp induced more M1 macrophages and neutrophils compared with the wild-type mice after CLP. Mice pre-treated with cholecalciferol (an inactive form of vitamin D3) or treated with 1alpha, 25-dihydroxyvitamin D3 (an active form of VD3) had decreased 7-day mortality and significantly less severe symptoms. Intriguingly, the administration of cholecalciferol after CLP led to worsened 7-day mortality and the associated symptoms.

Conclusions

Endogenous cathelicidin promotes intestinal barrier integrity accompanied by modulating the infiltration of neutrophils and macrophages in polymicrobial sepsis. Our data suggested that 1alpha, 25-dihydroxyvitamin D3 but not cholecalciferol is a potential therapeutic agent for treating sepsis.

The impact of the systemic inflammatory response on hepatic bacterial elimination in experimental abdominal sepsis

Background

Bacterial translocation from the gut has been suggested to induce a systemic inflammatory response syndrome (SIRS) and organ dysfunction. The liver has a pivotal role in eliminating circulating bacteria entering from the gut. We investigated whether pre-existing inflammation affects hepatic bacterial elimination.

Methods

Fifteen anaesthetised piglets were infused with E. coli in the portal vein for 3 h. The naive group (n = 6) received the bacterial infusion without endotoxin exposure. SIRS (SIRS group, n = 6) was induced by endotoxin infusion 24 h before the bacterial infusion. For effects of anaesthesia, controls (n = 3) received saline instead of endotoxin for 24 h. Bacterial counts and endotoxin levels in the portal and hepatic veins were analysed during bacterial infusion.

Results

The bacterial killing rate was higher in the naive group compared with the SIRS group (p = 0.001). The ratio of hepatic to portal venous bacterial counts, i.e. the median bacterial influx from the splanchnic circulation, was 0.06 (IQR 0.01–0.11) in the naive group and 0.71 (0.03–1.77) in the SIRS group at 3 h, and a magnitude lower in the naive group during bacteraemia (p = 0.03). Similar results were seen for hepatic endotoxin elimination. Peak log tumour necrosis factor alpha was higher in the naive 4.84 (4.77–4.89) vs. the SIRS group 3.27 (3.26–3.32) mg/L (p < 0.001).

Conclusions

Our results suggest that hepatic bacterial and endotoxin elimination is impaired in pigs with pre-existing SIRS while the inflammatory response to bacterial infusion is diminished. If similar mechanisms operate in human critical illness, the hepatic elimination of bacteria from the gut could be impaired by SIRS.

Electronic supplementary material

The online version of this article (10.1186/s40635-019-0266-x) contains supplementary material, which is available to authorized users.

Emphysematous Aortitis due to Clostridium septicum in an 89-Year-Old Female with Ileus

Emphysematous aortitis is a rare but lethal form of infectious vasculitis. This condition was found incidentally on computed tomography of the chest during the evaluation of a patient presenting with pneumonia coincident with adynamic ileus. The patient did not have a history of malignancy. While colon cancer could not be ruled out, it is possible that ileus may have contributed to or resulted in bacterial translocation in this case. Appropriate investigations and empirical therapy against Clostridium septicum should be initiated in the presence of clinical and radiological findings suggestive of emphysematous aortitis.

How the Interplay Between the Commensal Microbiota, Gut Barrier Integrity, and Mucosal Immunity Regulates Brain Autoimmunity

The intestinal barrier provides the host with a strong defense line against the external environment playing also a pivotal role in the crosstalk between the gut microbiota and the immune system. Notably, increasing lines of evidence concerning autoimmune disorders such as Multiple Sclerosis (MS) report an imbalance in both intestinal microbiota composition and mucosal immunity activation, along with an alteration of gut barrier permeability, suggesting this complex network plays a crucial role in modulating the course of autoimmune responses occurring in tissues outside the gut such as the central nervous system (CNS). Here, we review current knowledge on how gut inflammation and breakage of gut barrier integrity modulates the interplay between the commensal gut microbiota and the immune system and its role in shaping brain immunity.

Microbiota-Immune Interaction in the Pathogenesis of Gut-Derived Infection

Gut-derived infection is among the most common complications in patients who underwent severe trauma, serious burn, major surgery, hemorrhagic shock or severe acute pancreatitis (SAP). It could cause sepsis and multiple organ dysfunction syndrome (MODS), which are regarded as a leading cause of mortality in these cases. Gut-derived infection is commonly caused by pathological translocation of intestinal bacteria or endotoxins, resulting from the dysfunction of the gut barrier. In the last decades, the studies regarding to the pathogenesis of gut-derived infection mainly focused on the breakdown of intestinal epithelial tight junction and increased permeability. Limited information is available on the roles of intestinal microbial barrier in the development of gut-derived infection. Recently, advances of next-generation DNA sequencing techniques and its utilization has revolutionized the gut microecology, leading to novel views into the composition of the intestinal microbiota and its connections with multiple diseases. Here, we reviewed the recent progress in the research field of intestinal barrier disruption and gut-derived infection, mainly through the perspectives of the dysbiosis of intestinal microbiota and its interaction with intestinal mucosal immune cells. This review presents novel insights into how the gut microbiota collaborates with mucosal immune cells to involve the development of pathological bacterial translocation. The data might have important implication to better understand the mechanism underlying pathological bacterial translocation, contributing us to develop new strategies for prevention and treatment of gut-derived sepsis.

Neonatal sepsis due to glycopeptide resistant Enterococcus faecium from colonized maternal gut- rare case evidence

Background

Vancomycin-resistant enterococcal infections in the neonatal ICU are growing global problems. We report a case of neonatal septicemia by multidrug-resistant vancomycin-resistant Enterococcus faecium (VRE), the source of infection being the mother's gut.

Case presentation

A newborn male child admitted to the neonatal intensive care unit (NICU) was diagnosed to have mild meconium aspiration syndrome, early onset neonatal septicemia, and bacteremia by multidrug and vancomycin-resistant Enterococcus faecium. Screening of gut flora of the baby and the mother were carried out to trace the source of infection. Stool cultures of the mother and the baby yielded Vancomycin-Resistant Enterococcus faecium. All three isolates of Enterococcus faecium had similar antibiogram, harbored the vanA gene and similar pulsed-field gel electrophoresis pattern. Baby responded to the 1 week therapy with oral linezolid suspension 20 mg/kg/day, 1 ml/t.d.s. No VRE was isolated from baby on a repeat stool culture 1 week after the linezolid therapy. He was discharged with the advice for the continuance of linezolid for seven more days.

Conclusion

Isolation of MDR-VRE from the blood culture of the baby and stool specimens of the mother and the baby with the same antibiogram profile and clonal similarities reveals that maternal gut colonization was responsible for neonatal sepsis. Optimal infection control measures and the development of guidelines for monitoring VRE colonization in pregnant women might be useful in reducing the occurrence of neonatal sepsis.

Pathophysiology of Acute Illness and Injury

The pathophysiology of acute illness and injury recognizes three main effectors: infection, trauma, and ischemia-reperfusion injury. Each of them can act by itself or in combination with the other two in developing a systemic inflammatory reaction syndrome (SIRS) that is a generalized reaction to the morbid event. The time course of SIRS is variable and influenced by the number and severity of subsequent insults (e.g., reparative surgery, acquired hospital infections). It occurs simultaneously with a complex of counter-regulatory mechanisms (compensatory anti-inflammatory response syndrome, CARS) that limit the aggressive effects of SIRS. In adjunct, a progressive dysfunction of the acquired (lymphocytes) immune system develops with increased risk for immunoparalysis and associated infectious complications. Both humoral and cellular effectors participate to the development of SIRS and CARS. The most important humoral mediators are pro-inflammatory (IL-1β, IL-6, IL-8, IL-12) and anti-inflammatory (IL-4, IL-10) cytokines and chemokines, complement, leukotrienes, and PAF. Effector cells include neutrophils, monocytes, macrophages, lymphocytes, and endothelial cells. The endothelium is a key factor for production of remote organ damage as it exerts potent chemo-attracting effects on inflammatory cells, allows for leukocyte trafficking into tissues and organs, and promotes further inflammation by cytokines release. Moreover, the loss of vasoregulatory properties and the increased permeability contribute to the development of hypotension and tissue edema. Finally, the disseminated activation of the coagulation cascade causes the widespread deposition of microthrombi with resulting maldistribution of capillary blood flow and ultimately hypoxic cellular damage. This mechanism together with increased vascular permeability and vasodilation is responsible for the development of the multiple organ dysfunction syndrome (MODS).

Synergistic convergence of microbiota-specific systemic IgG and secretory IgA

BACKGROUND

Commensals induce local IgA responses essential to the induction of tolerance to gut microbiota, but it remains unclear whether antimicrobiota responses remain confined to the gut.

OBJECTIVE

The aim of this study was to investigate systemic and intestinal responses against the whole microbiota under homeostatic conditions and in the absence of IgA.

METHODS

We analyzed blood and feces from healthy donors, patients with selective IgA deficiency (SIgAd), and patients with common variable immunodeficiency (CVID). Immunoglobulin-coated bacterial repertoires were analyzed by using combined bacterial fluorescence-activated cell sorting and 16S rRNA sequencing. Bacterial lysates were probed by using Western blot analysis with healthy donor sera.

RESULTS

Although absent from the healthy gut, serum antimicrobiota IgG are present in healthy subjects and increased in patients with SIgAd. IgG converges with nonoverlapping secretory IgA specificities to target the same bacteria. Each individual subject targets a diverse microbiota repertoire with a proportion that correlates inversely with systemic inflammation. Finally, intravenous immunoglobulin preparations target CVID gut microbiota much less efficiently than healthy microbiota.

CONCLUSION

Secretory IgA and systemic IgG converge to target gut microbiota at the cellular level. SIgAd-associated inflammation is inversely correlated with systemic anticommensal IgG responses, which might serve as a second line of defense. We speculate that patients with SIgAd could benefit from oral IgA supplementation. Our data also suggest that intravenous immunoglobulin preparations can be supplemented with IgG from IgA-deficient patient pools to offer better protection against gut bacterial translocations in patients with CVID.

Pyosalpinx complicating chronic hydrosalpinx in a 50-year old virgo woman: a case report

Background

Pelvic inflammatory disease is an infection of the upper genital tract, including the uterus, ovaries, uterine tubes, and pelvic peritoneum. Tubo-ovarian abscess and pyosalpinx are common complications associated with pelvic inflammatory disease. They are usually encountered in sexually active women, but rare cases in Virgos have also been described.

Case presentation

Here, we report the case of a 50-year-old Virgo woman presenting with pyosalpinx secondary to previous laparotomic sigmoidectomy for acute diverticulitis. Inflammation caused by the woman’s diverticulitis and laparotomic surgery could have been the origin of her left uterine tube occlusion and consequent hydrosalpinx development. The contact between the rectum and left uterine tube observed in our patient suggests that superinfection of the hydrosalpinx could have occurred secondary to bacterial translocation. The patient’s condition was managed with laparoscopic left salpingectomy and antibiotic therapy, which resulted in complete resolution.

Conclusions

Regardless of sexual history, pelvic inflammatory disease should be considered in all women with abdominal pain. Diagnosing pelvic inflammatory disease in Virgos could be very challenging, but its recognition and appropriate treatment are indispensable because of the potential long-term complications.

Autologous white blood cell infusion for trauma, brain trauma, stroke and select immune dysfunction co-morbidities: A promising and timely proposal?

All traumas suppress the immune system, resulting in higher morbidity and mortality. Infections, poor nutritional status, chronic illness, fatigue, therapies or procedures performed during and after transport also negatively affect the immune system. Large populations are impacted by trauma worldwide and suffer enormous costs in both direct and indirect expenditures from physical, psychological and functional losses. Most therapies and studies of trauma, brain trauma, stroke, immune suppression and their co-morbidities do not address nor discuss methods that promote immune system resuscitation or efficacy to support its role in post-trauma healing and rehabilitation. These omissions present an opportunity for using autologous stored naïve (unexposed to the current trauma and co-morbidities) white blood cell infusions (autologous white blood cell infusion) (AWBCI) to supplement treatment of most traumas, trauma-associated infections, other co-morbidities and immune suppression derived problems in order to improve the global standard of trauma care. We hypothesize to give the traumatized patients back their own immune system that has been 'stored' in some fashion, either cryogenically or just after or during the trauma event [surgery, etc for example]. We emphasize that other treatments should not be replaced - rather we suggest AWBCI as concurrent therapy. We present focused select animal and human studies as proofs of concept to arrive at and support our therapeutic suggestion and hypotheses, flowing historically from donor white blood cell therapy [DLI] to close cohort white blood cell therapy to autologous white blood cell infusion [AWBCI]. We integrate the concept of personalized medicine from an evidence-based framework while maintaining scientific rigor and statistical proof as a basis of our hypotheses.

Identification and Characterization of Blood and Neutrophil-Associated Microbiomes in Patients with Severe Acute Pancreatitis Using Next-Generation Sequencing

Infectious complications are a leading cause of death for patients with severe acute pancreatitis (SAP). Yet, our knowledge about details of the blood microbial landscape in SAP patients remains limited. Recently, some studies have reported that the peripheral circulation harbors a diverse bacterial community in healthy and septic subjects. The objective of this study was to examine the presence of the blood bacterial microbiome in SAP patients and its potential role in the development of infectious complications. Here we conducted a prospective observational study on a cohort of 50 SAP patients and 12 healthy subjects to profile the bacterial composition in the blood. The patients were subgrouped into uninfected (n = 17), infected (n = 16), and septic (n = 17) cases. Applying 16S rDNA-based next-generation sequencing technique, we investigated blood and neutrophil-associated microbiomes in SAP patients, and assessed their connections with immunological alterations. Based on the sequencing data, a diverse bacterial microbiota was found in peripheral blood and neutrophils from the healthy and SAP subjects. As compared to healthy controls, the blood and neutrophil-associated microbiomes in the patients were significantly altered, with an expansion in Bacteroidetes and Firmicutes as well as a decrease in Actinobacteria. Variations in the microbiome composition in patients were associated with immunological disorders, including altered lymphocyte subgroups, elevated levels of serum cytokines and altered proteomic profiles of neutrophils. However, no significant compositional difference was observed between the patient subgroups, implying that the microbiota alterations might not be linked to presence/absence of infectious complications in SAP. Together, we present an initial description of the blood and neutrophil-associated bacterial profiles in SAP patients, offering novel evidence for the existence of the blood microbiome. Identification of the blood microbiome provides novel insights into characteristics and diagnostics of bacteremia in the patients. Further study is required to assess the possible implications of the blood microbiome in health and diseases.

Physiological Translocation of Lactic Acid Bacteria during Pregnancy Contributes to the Composition of the Milk Microbiota in Mice

The human milk microbiota is a complex and diverse ecosystem that seems to play a relevant role in the mother-to-infant transmission of microorganisms during early life. Bacteria present in human milk may arise from different sources, and recent studies suggest that at least some of them may be originally present in the maternal digestive tract and may reach the mammary gland through an endogenous route during pregnancy and lactation. The objective of this work was to elucidate whether some lactic acid bacteria are able to translocate and colonize the mammary gland and milk. For this purpose, two lactic acid bacteria strains (Lactococcus lactis MG1614 and Lactobacillus salivarius PS2) were transformed with a plasmid containing the lux genes; subsequently, the transformed strains were orally administered to pregnant mice. The murine model allowed the visualization, isolation, and Polymerase Chain Reaction (PCR)-detection of the transformed bacteria in different body locations, including mammary tissue and milk, reinforcing the hypothesis that physiological translocation of maternal bacteria during pregnancy and lactation may contribute to the composition of the mammary and milk microbiota.

Role for FimH in Extraintestinal Pathogenic Escherichia coli Invasion and Translocation through the Intestinal Epithelium

The translocation of bacteria across the intestinal epithelium of immunocompromised patients can lead to bacteremia and life-threatening sepsis. Extraintestinal pathogenic Escherichia coli (ExPEC), so named because this pathotype infects tissues distal to the intestinal tract, is a frequent cause of such infections, is often multidrug resistant, and chronically colonizes a sizable portion of the healthy population. Although several virulence factors and their roles in pathogenesis are well described for ExPEC strains that cause urinary tract infections and meningitis, they have not been linked to translocation through intestinal barriers, a fundamentally distant yet important clinical phenomenon. Using untransformed ex situ human intestinal enteroids and transformed Caco-2 cells, we report that ExPEC strain CP9 binds to and invades the intestinal epithelium. ExPEC harboring a deletion of the gene encoding the mannose-binding type 1 pilus tip protein FimH demonstrated reduced binding and invasion compared to strains lacking known E. coli virulence factors. Furthermore, in a murine model of chemotherapy-induced translocation, ExPEC lacking fimH colonized at levels comparable to that of the wild type but demonstrated a statistically significant reduction in translocation to the kidneys, spleen, and lungs. Collectively, this study indicates that FimH is important for ExPEC translocation, suggesting that the type 1 pilus is a therapeutic target for the prevention of this process. Our study also highlights the use of human intestinal enteroids in the study of enteric diseases.

Influence of indigenous microbiota on experimental toxoplasmosis in conventional and germ-free mice

Toxoplasmosis represents one of the most common zoonoses worldwide. Its agent, Toxoplasma gondii, causes a severe innate pro-inflammatory response. The indigenous intestinal microbiota promotes host animal homoeostasis and may protect the host against pathogens. Germ-free (GF) animals provide an important tool for the study of interactions between host and microbiota. In this study, we assessed the role of indigenous microorganisms in disease development utilizing a murine toxoplasmosis model, which includes conventional (CV) and GF NIH Swiss mice. CV and GF mice orally inoculated with T. gondii had similar survival curves. However, disease developed differently in the two animal groups. In CV mice, intestinal permeability increased and levels of intestinal pro-inflammatory cytokines were altered. In GF animals, there were discrete epithelial degenerative changes and mucosal oedema, but the liver and lungs displayed significant lesions. We conclude that, despite similar survival curves, CV animals succumb to an exaggerated inflammatory response, whereas GF mice fail to produce an adequate systemic response.