Abdominal rubber drain piece aggravates intra-abdominal sepsis in the rat

Obeticholic Acid Decreases Intestinal Content of Enterococcus in Rats With Cirrhosis and Ascites

The intestinal microbiome and bacterial translocation (BT), the passage of microorganisms from the gut lumen to mesenteric lymph nodes and other extra-intestinal sites, are main mechanisms implicated in liver injury and further decompensation in patients with cirrhosis. We hypothesized that obeticholic acid (OCA), a semisynthetic bile acid, would change the microbiome composition and reduce bacterial translocation in experimental cirrhosis. Rats with cirrhosis induced by carbon tetrachloride inhalation (a nonseptic model) with ascites present for at least 7 days were randomized to receive a 14-day course of OCA at a dose of 5 mg/kg/day (n = 34) or placebo (n = 34). Stool was collected at days 1 (randomization), 8, and 14 (sacrifice) for analysis of intestinal microbiome using the V4 hypervariable region of the bacterial 16S gene amplified by polymerase chain reaction. Bacteriological cultures of mesenteric lymph nodes, blood, and ascites were performed at end of study. Twenty-four animals in each group reached the end of study. Compared with placebo, rats treated with OCA had decreased relative abundance of Enterococcus in both ileum content (P = 0.02) and in stool (P < 0.001). BT from pathogenic bacteria was not different between groups. At end of treatment, rats on OCA had a significantly lower aspartate aminotransferase (AST) (266 vs. 369 IU/L; P < 0.01) and higher serum albumin (0.9 vs. 0.7 g/dL; P < 0.01) than rats on placebo. Conclusion: Although OCA did not appear to reduce BT by pathogenic bacteria, the reduction in intestinal content of Enterococcus, which has been associated with hepatocyte death, in OCA-treated animals is consistent with our observed improvements in AST and in liver function, as evidenced by higher serum albumin.

Mechanical Properties and Concentrations of Poly(ethylene glycol) in Hydrogels and Brushes Direct the Surface Transport of Staphylococcus aureus

Surface-associated transport of flowing bacteria, including cell rolling, is a mechanism for otherwise immobile bacteria to migrate on surfaces and could be associated with biofilm formation or the spread of infection. This work demonstrates how the moduli and/or local polymer concentration play critical roles in sustaining contact, dynamic adhesion, and transport of bacterial cells along a hydrogel or hydrated brush surface. In particular, stiffer more concentrated hydrogels and brushes maintained the greatest dynamic contact, still allowing cells to travel along the surface in flow. This study addressed how the mechanical properties, molecular architectures, and thicknesses of minimally adhesive poly(ethylene glycol) (PEG)-based coatings influence the flow-driven surface motion of Staphylococcus aureus MS2 cells. Three protein-repellant PEG-dimethylacrylate hydrogel films (∼100 μm thick) and two protein-repellant PEG brushes (8-16 nm thick) were sufficiently fouling-resistant to prevent the accumulation of flowing bacteria. However, the rolling or hopping-like motions of gently flowing S. aureus cells along the surfaces were specific to the particular hydrogel or brush, distinguishing these coatings in terms of their mechanical properties (with moduli from 2 to 1300 kPa) or local PEG concentrations (in the range 10-50% PEG). On the stiffer hydrogel coatings having higher PEG concentrations, S. aureus exhibited long runs of surface rolling, 20-50 μm in length, an increased tendency of cells to repeatedly return to some surfaces after rolling and escaping, and relatively long integrated contact times. By contrast, on the softer more dilute hydrogels, bacteria tended to encounter the surface for brief periods before escaping without return. The dynamic adhesion and motion signatures of the cells on the two brushes were bracketed by those on the soft and stiff hydrogels, demonstrating that PEG coating thickness was not important in these studies where the vertically oriented surfaces minimized the impact of gravitational forces. Control studies with similarly sized poly(ethylene oxide)-coated rigid spherical microparticles, that also did not arrest on the PEG coatings, established that the bacterial skipping and rolling signatures were specific to the S. aureus cells and not simply diffusive. Dynamic adhesion of the S. aureus cells on the PEG hydrogel surfaces correlated well with quiescent 24 h adhesion studies in the literature, despite the orientation of the flow studies that eliminated the influence of gravity on bacteria-coating normal forces.

Inflammatory mediators in intra-abdominal sepsis or injury - a scoping review

Introduction

Inflammatory and protein mediators (cytokine, chemokine, acute phase proteins) play an important, but still not completely understood, role in the morbidity and mortality of intra-abdominal sepsis/injury. We therefore systematically reviewed preclinical and clinical studies of mediators in intra-abdominal sepsis/injury in order to evaluate their ability to: (1) function as diagnostic/prognostic biomarkers; (2) serve as therapeutic targets; and (3) illuminate the pathogenesis mechanisms of sepsis or injury-related organ dysfunction.

Methods

We searched MEDLINE, PubMed, EMBASE and the Cochrane Library. Two investigators independently reviewed all identified abstracts and selected articles for full-text review. We included original studies assessing mediators in intra-abdominal sepsis/injury.

Results

Among 2437 citations, we selected 182 studies in the scoping review, including 79 preclinical and 103 clinical studies. Serum procalcitonin and C-reactive protein appear to be useful to rule out infection or monitor therapy; however, the diagnostic and prognostic value of mediators for complications/outcomes of sepsis or injury remains to be established. Peritoneal mediator levels are substantially higher than systemic levels after intra-abdominal infection/trauma. Common limitations of current studies included small sample sizes and lack of uniformity in study design and outcome measures. To date, targeted therapies against mediators remain experimental.

Conclusions

Whereas preclinical data suggests mediators play a critical role in intra-abdominal sepsis or injury, there is no consensus on the clinical use of mediators in diagnosing or managing intra-abdominal sepsis or injury. Measurement of peritoneal mediators should be further investigated as a more sensitive determinant of intra-abdominal inflammatory response. High-quality clinical trials are needed to better understand the role of inflammatory mediators.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1093-4) contains supplementary material, which is available to authorized users.

Use of an active intra-abdominal drain in 67 horses

OBJECTIVE

To describe the insertion technique, efficacy, and complications associated with the use of an active (closed-suction) abdominal drain in horses.

STUDY DESIGN

Retrospective study. Animals-Sixty-seven horses with abdominal contamination treated by abdominal lavage and use of a closed-suction abdominal drain.

METHODS

Medical records of horses (1989-1996) that had a closed-suction abdominal drain were reviewed. Follow-up information was obtained by telephone interviews with owners.

RESULTS

Sixty-eight closed-suction abdominal drains were used in 67 horses that had abdominal contamination, peritonitis, or to prevent adhesion formation. The drain was placed under general anesthesia (62 horses) or in a standing position (6 horses). Abdominal lavage was performed every 4 to 12 hours and about 83% of the peritoneal lavage solution was retrieved. Minor complications associated with drain use occurred in 49% of the horses and included obstruction or slow passage of fluid through the drain in 18 horses (26%), leakage of fluid around the drain in 11 horses (16%), and subcutaneous fluid accumulation around the drain in 8 horses (12%). Incisional suppuration developed in 20 of 62 (32%) and incisional herniation in 5 of 46 (11%) horses.

CONCLUSIONS

A closed-suction drain system was easily placed and was associated with only minor complications in most horses.

CLINICAL RELEVANCE

Active abdominal drainage and lavage is a useful adjunct in the treatment of peritonitis or as a prophylactic procedure in horses at risk of developing septic peritonitis and abdominal adhesions. Clinicians should be aware of the high incidence of minor complications.

The pathobiology of peritonitis

The peritoneum is more than a mechanical covering that allows for the easy gliding of opposed peritoneal surfaces. The peritoneal mesothelial cells facilitate the action of powerful innate immune mechanisms. In addition, the peritoneal-associated lymphoid tissues contain unique cells that may play a crucial role in the localization of intraperitoneal infection. A clearer understanding of the molecular and cellular events underlying peritoneal functions in both the unstimulated and stimulated state will aid future treatment of peritonitis.