Lactobacillus plantarum 299v does not reduce enteric bacteria or bacterial translocation in patients undergoing colon resection.

BACKGROUND: Probiotics may exert beneficial effects in the gastrointestinal tract. This randomized trial investigated the effect of the probiotic Lactobacillus plantarum 299v on the intestinal load of potentially pathogenic bacteria, bacterial translocation, and cell proliferation in elective colon surgery. METHODS: Seventy-five patients were randomized to pre- and postoperative oral intake of Lactobacillus plantarum 299v or placebo. Rectal swabs and mucosal biopsies were taken before the start of intake, after 1 week, at surgery, and after 6 days, weeks, and months. Viable counts were quantified for clostridia, Enterobacteriaceae, Gram-negative anaerobes, and lactobacilli. Bacterial translocation was determined by the analysis of bacterial DNA genes in mesenteric lymph nodes. Ki-67 was used as a marker of cell proliferation in normal mucosa and tumor. RESULTS: Lactobacillus plantarum 299v was given without adverse effects. Lactobacillus plantarum 299v as well as Enterobacteriaceae and Gram-negative anaerobes increased in the colon 1 week after the administration of Lactobacillus plantarum 299v. There were no significant differences between patients receiving Lactobacillus plantarum 299v and placebo in the incidence of bacterial translocation (27 vs. 13%) and postoperative complications (16 vs. 31%). CONCLUSIONS: Lactobacillus plantarum 299v was established in the intestine, but no inhibitory effect on enteric bacteria, bacterial translocation, or postoperative complications was found. The mechanism behind the protective effects of probiotics found in animal and some human studies remain elusive and require further explorations. No adverse effects were recorded after the administration of high doses of Lactobacillus plantarum 299v.

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.

Convergence in probiotic Lactobacillus gut-adaptive responses in humans and mice.

Probiotic bacteria provide unique opportunities to study the global responses and molecular mechanisms underlying the effects of gut-associated microorganisms in the human digestive tract. In this study, we show by comparative transcriptome analysis using DNA microarrays that the established probiotic Lactobacillus plantarum 299v specifically adapts its metabolic capacity in the human intestine for carbohydrate acquisition and expression of exopolysaccharide and proteinaceous cell surface compounds. This report constitutes the first application of global gene expression profiling of a commensal microorganism in the human gut. A core L. plantarum transcriptome expressed in the mammalian intestine was also determined through comparisons of L. plantarum 299v activities in humans to those found for L. plantarum WCFS1 in germ-free mice. These results identify the niche-specific adaptations of a dietary microorganism to the intestinal ecosystem and provide novel targets for molecular analysis of microbial-host interactions which affect human health.

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.

BACKGROUND: 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 APC gene mutation, possible genotype-phenotype correlations largely remain to be defined for the extracolonic manifestations. METHODS: Full genomic sequencing combined with multiplex ligation-dependent probe amplification was used to identify APC gene mutations, which were correlated to the clinical presentations. RESULTS: 10 novel APC 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'APC mutation (c.5030_5031insAA) developed colon cancer at age 72 as the first manifestation of attenuated FAP. CONCLUSION: 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 APC 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.

Phenotypic heterogeneity in hereditary non-polyposis colorectal cancer: identical germline mutations associated with variable tumour morphology and immunohistochemical expression.

BACKGROUND: Hereditary non-polyposis colorectal cancer (HNPCC) is associated with high risks for colorectal and endometrial cancer, young age at onset and an increased risk of multiple primary tumours. Colorectal cancer in HNPCC is characterised by poor tumour differentiation, an expanding growth pattern, and a pronounced lymphocytic reaction with tumour-infiltrating lymphocytes. AIMS AND METHODS: The mutation spectrum in HNPCC is diverse and in order to clarify whether the HNPCC tumour phenotype is influenced by the underlying genetic alteration, 29 colorectal cancers and 12 adenomas from 24 individuals in two HNPCC families were morphologically and immunohistochemically characterised. RESULTS: The tumour morphology as well as the immunohistochemical expression of beta-catenin varied extensively within the families as well as between synchronous/metachronous colorectal cancers from the same individual. Poor tumour differentiation, an expanding growth pattern, and tumour-infiltrating lymphocytes occurred at higher frequencies in proximal tumours, whereas distal colorectal cancers often lacked distinct HNPCC-associated morphological features. CONCLUSIONS: The clinical, morphological and immunohistochemical variability observed within these families indicates that other mechanisms than the underlying germline mutation influence the HNPCC phenotype. Since morphological features linked to HNPCC are less frequent in distal cancers, it may be particularly relevant to obtain family history and age of onset in these tumours in order to identify individuals with HNPCC.

Adhesive capability of Lactobacillus plantarum 299v is important for preventing bacterial translocation in endotoxemic rats.

The preventive effect of the probiotic Lactobacillus plantarum 299v on bacterial translocation (BT) and the role of adhesion were studied in septic rats. Five groups of rats were pretreated as follows: negative and positive control groups received regular drinking water; the oatmeal group received drinking water mixed with oatmeal; the Lp 299v group received drinking water mixed with oatmeal containing 10(9) colony-forming units (CFU) L. plantarum 299v/ml; the Lp 299v-adh(-) group received drinking water with oatmeal containing 10(9) CFU/ml of modified L. plantarum 299v (L. plantarum 299v-adh(-)) lacking adhesive properties to enterocytes. On day 8, all rats except the negative control group were given lipopolysaccharide (LPS) intraperitoneally. After 24 h, mesenteric lymph node (MLN), liver and ileum were harvested for culture. Incidence of BT after LPS challenge was 25% and 88% in MLN and liver, respectively. BT increased to 75% in MLN and 100% in liver of endotoxemic rats pretreated with oatmeal. Pretreatment with L. plantarum 299v reduced BT to 0% and 12% in MLN and liver, respectively. L. plantarum 299v-adh(-) did not prevent BT to MLN. Flow cytometry revealed reduced adherence of these bacteria to intestinal epithelial cells compared to L. plantarum 299v. Thus, L. plantarum 299v prevents BT in septic rats, an effect probably dependent on bacterial adherence to the intestinal mucosa. Further, our findings indicate that oatmeal (prebiotics) without probiotics does not prevent BT during sepsis.

Lactobacillus plantarum 299v inhibits Escherichia coli-induced intestinal permeability.

The purpose of this work was to investigate whether a probiotic bacterium, Lactobacillus plantarum 299v, could affect Escherichia coli-induced passage of mannitol across the intestinal wall. Sprague-Dawley rats were pretreated for one week by either tube feeding with L. plantarum 299v twice daily, free access to L. plantarum 299v by adding the bacterium in the drinking water, or negative control receiving regular feeding. Intestinal segments were mounted in Ussing chambers and the mucosa was exposed to control medium, E. coli, and L. plantarum 299v (alone or together). [14C]Mannitol was added as a marker of intestinal permeability and samples were taken from the serosal side. E. coli exposure induced a 53% increase in mannitol passage across the intestinal wall (P < 0.05). One week of pretreatment with L. plantarum 299v in the drinking water abolished the E. coli-induced increase in permeability. Tube feeding for one week or short-term addition of L. plantarum 299v in the Ussing chambers had no effect on the permeability provoked by E. coli challenge. Notably, L. plantanum 299v itself did not change the intestinal passage of mannitol. These data demonstrate that pretreatment with L. plantarum 299v, which is a probiotic bacterium, protects against E. coli-induced increase in intestinal permeability, and that L. plantarum 299v alone has no influence on the intestinal permeability. Thus, this study supports the concept that probiotics may exert beneficial effects in the gastrointestinal tract.