Use of Probiotics as Prophylaxis for Postoperative Infections

Postoperative bacterial infections are common despite prophylactic administration of antibiotics. The wide-spread use of antibiotics in patients has contributed to the emergence of multiresistant bacteria. A restricted use of antibiotics must be followed in most clinical situations. In surgical patients there are several reasons for an altered microbial flora in the gut in combination with an altered barrier function leading to an enhanced inflammatory response to surgery. Several experimental and clinical studies have shown that probiotics (mainly lactobacilli) may reduce the number of potentially pathogenia bacteria (PPM) and restore a deranged barrier function. It is therefore of interest to test if these abilities of probiotics can be utilized in preoperative prophylaxis. These factors may be corrected by perioperative administration of probiotics in addition to antibiotics. Fourteen randomized clinical trials have been presented in which the effect of such regimens has been tested. It seems that in patients undergoing liver transplantation or elective surgery in the upper gastrointestinal tract prophylactic administration of different probiotic strains in combination with different fibers results in a three-fold reduction in postoperative infections. In parallel there seems to be a reduction in postoperative inflammation, although that has not been studied in a systematic way. The use of similar concepts in colorectal surgery has not been successful in reducing postoperative infections. Reasons for this difference are not obvious. It may be that higher doses of probiotics with longer duration are needed to influence microbiota in the lower gastrointestinal tract or that immune function in colorectal patients may not be as important as in transplantation or surgery in the upper gastrointestinal tract. The favorable results for the use of prophylactic probiotics in some settings warrant further controlled studies to elucidate potential mechanisms, impact on gut microbiota and influence on clinical management. The use of probiotics must be better delineated in relation to type of bacteria, dose and length of administration

Mechanism of action of probiotics

The modern diet doesn't provide the required amount of beneficial bacteria. Maintenance of a proper microbial ecology in the host is the main criteria to be met for a healthy growth. Probiotics are one such alternative that are supplemented to the host where by and large species of Lactobacillus, Bifidobacterium and Saccharomyces are considered as main probiotics. The field of probiotics has made stupendous strides though there is no major break through in the identification of their mechanism of action. They exert their activity primarily by strengthening the intestinal barrier and immunomodulation. The main objective of the study was to provide a deep insight into the effect of probiotics against the diseases, their applications and proposed mechanism of action

Broad phenotypic spectrum in familial adenomatous polyposis; from early onset and severe phenotypes to late onset of attenuated polyposis with the first manifestation at age 72

<p>Abstract</p> <p>Background</p> <p>Familial adenomatous polyposis (FAP) is typically characterized by multiple colonic polyps and frequent extracolonic features. Whereas the number of colonic polyps has been linked to the <it>APC </it>gene mutation, possible genotype-phenotype correlations largely remain to be defined for the extracolonic manifestations.</p> <p>Methods</p> <p>Full genomic sequencing combined with multiplex ligation-dependent probe amplification was used to identify <it>APC </it>gene mutations, which were correlated to the clinical presentations.</p> <p>Results</p> <p>10 novel <it>APC </it>gene mutations were identified in 11 families. A broad spectrum of extracolonic manifestations was identified in most of these individuals. Two sisters with an insertion in codon 528 (c.1582_1583insGC) both showed severe phenotypes with classical polyposis, upper gastrointestinal polyps and thyroid cancer. A woman with a 3'<it>APC </it>mutation (c.5030_5031insAA) developed colon cancer at age 72 as the first manifestation of attenuated FAP.</p> <p>Conclusion</p> <p>With an increasing number of FAP families diagnosed, a broad and variable tumor spectrum and a high frequency of extracolonic manifestations are gradually recognized. We report novel <it>APC </it>mutations and present two FAP cases that suggest familial aggregation of thyroid cancer and demonstrate the need to consider attenuated FAP also among elderly patients with colon cancer.</p

In vitro study on the cell adhesion ability of immobilized lactobacilli on natural supports

The aim of the present study was to investigate the effect of probiotic immobilization onto wheat grains, both wet and freeze dried, on the adhesion properties of the probiotic cells and make comparisons with wet and freeze dried free cells. Lactobacillus casei ATCC 393 and Lactobacillus plantarum NCIMB 8826 were used as model probiotic strains. The results showed satisfactory adhesion ability of free cells to a monolayer of Caco-2 cells (> 1000 CFU/100 Caco-2 cells for wet cells). Cell immobilization resulted in a significant decrease in adhesion, for both wet and freeze dried formulations, most likely because immobilized cells did not have direct access to the Caco-2 cells, but it still remained in adequate levels (> 100 CFU/100 Caco-2 cells for wet cells). No clear correlation could be observed between cell adhesion and the hydrophobicity of the bacterial cells, measured by the hexadecane adhesion assay. Most notably, immobilization enhanced the monolayer integrity of Caco-2 cells, demonstrated by a more than 2-fold increase in transepithelial electrical resistance (TEER) compared to free cells. SEM micrographs ascertained the adhesion of both immobilized and free cells to the brush border microvilli. Finally, the impact of the food matrix on the adhesion properties of probiotic bacteria and on the design of novel functional products is discussed

Gut-central nervous system axis is a target for nutritional therapies

Historically, in the 1950s, the chemist Linus Pauling established a relationship between decreased longevity and obesity. At this time, with the advent of studies involving the mechanisms that modulate appetite control, some researchers observed that the hypothalamus is the "appetite centre" and that peripheral tissues have important roles in the modulation of gut inflammatory processes and levels of hormones that control food intake. Likewise, the advances of physiological and molecular mechanisms for patients with obesity, type 2 diabetes mellitus, inflammatory bowel diseases, bariatric surgery and anorexia-associated diseases has been greatly appreciated by nutritionists. Therefore, this review highlights the relationship between the gut-central nervous system axis and targets for nutritional therapies

On Lactobacillus plantarum 299v, bacterial translocation and intestinal permeability.

The gastrointestinal tract harbours a huge load of bacteria which exerts important biological functions to maintain health. In certain conditions the relation between commensal bacteria and pathogens may be set off balance, with an increase in number of pathogens and risk of bacterial translocation (BT). Disease and trauma may also render the intestinal barrier dysfunctional, inducing BT and increased permeability. Probiotic bacteria, i.e. living bacteria which, when ingested, exerts beneficial effects on the host, have been found to stabilize the intestinal mucosa and affect the intestinal microflora. The aim of this thesis was to study the effects of Lactobacillus plantarum 299v in relation to intestinal permeability and BT. In study I L. plantarum 299v normalized E. coli-induced permeability in distal ileum of rats. This effect was achieved with a more continuous supply of L. plantarum 299v, rather than intermittent or acute pretreatment. Study II showed that pretreatment with L. plantarum 299v prevented BT in rats rendered septic with LPS. The protective effect seemed to be dependent on the ability of L. plantarum 299v to adhere to intestinal mucosa, indicating competitive inhibition as a possible mechanism behind prevention of translocation. Moreover, treatment with prebiotics, without a probioticum, did not prevent translocation. In study III LPS-induced intestinal barrier dysfunction on rats was found to be regulated by P-selectin-dependent leukocyte recruitment. With anti-P-selectin antibody intestinal permeability was attenuated, as well as leukocyte rolling and adhesion. This indicates anti-P-selectin treatment as a mean of ameliorating barrier dysfunction in sepsis. Finally, in study IV, it was found that high doses of L. plantarum 299v given to patients undergoing colon surgery were not able to reduce translocation of selected enteric bacteria but seemed to have a stimulatory effect on bacterial load in the colon. Further, L. plantarum 299v could be given to patients with malignancy without risk of tumour proliferation. Taken together, the findings herein indicates a potential of L. plantarum 299v pretreatment in reducing BT and intestinal permeability and warrants further studies in the clinical setting

Critical role of P-selectin-dependent leukocyte recruitment in endotoxin-induced intestinal barrier dysfunction in mice.

Objective: To define the importance of leukocyte recruitment in endotoxin-induced gut permeability. Materials and methods: 31 male C57BL/6 mice were challenged with lipopolysaccharide (LPS). Ileal permeability was measured in Ussing chambers and leukocyte-endothelium interactions studied with intravital fluorescence microscopy after 18 h. Results: LPS caused a clear-cut increase in leukocyte accumulation and intestinal permeability. Immunoneutralisation of P-selectin not only reduced leukocyte recruitment significantly (54% reduction) but also abolished endotoxin-induced intestinal leakage. Intestinal levels of pro-inflammatory chemokines increased markedly in response to LPS but were not influenced by inhibition of P-selectin in vivo. Conclusion: The present study shows not only that endotoxin-induced leukocyte recruitment is mediated by P-selectin but also that sepsis-associated intestinal leakage in the gut is largely regulated by leukocyte accumulation. Thus, our novel data demonstrate a critical link between P-selectin-dependent leukocyte recruitment and gut barrier failure in endotoxemia