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Microbial ecology studies have provided convincing evidence for the crosstalk between members of the autochthonous microbiota and the host immune system. The tight interrelationship between microbiota and host mucosal cells are mediated by microbial metabolites that are responsible for bacterial cell-to-cell communication by quorum-sensing mechanisms and also through the activation of eukaryotic cells following secretion of host defensins and modulation of cytokine expression profiles. All these host functions can be positively influenced by probiotic bacteria of human origin. However, few requirements for evaluating these strains for use in humans have been set according to their composition and metabolic activity. In this article, we have reported the scientific data published to date on the advantages of either mono- or multispecies probiotic products based on the outcome of the most significant clinical trials. According to published clinical trials, the efficacy of probiotic intervention for infectious or antimicrobial treatment-induced diarrhea, caused by different opportunistic bacterial or viral pathogens, was 48%. The probiotic preparations' efficacy for silencing the clinical symptoms of IBS was 75% and for attenuating the inflammatory response during IBD was 83% whereas multistrain probiotics appear to have better efficacy. [ABSTRACT FROM AUTHOR]

Endoscopic biliary stenting is today the most common palliative treatment for patients suffering from obstructive jaundice associated with malignant hepatobiliary tumors or benign strictures. However, recurrent jaundice, with or without cholangitis, is a major complication of a biliary endoprosthesis insertion. Thus, stent removal and replacement with a new one frequently occurs as a consequence of device blockage caused by microbial biofilm growth and biliary sludge accumulation in the lumen. Factors and mechanisms involved in plastic stent clogging arising from epidemiological, clinical and experimental data, as well as the possible strategies to prevent biliary stent failure, will be reviewed and discussed. [ABSTRACT FROM AUTHOR]

This review focuses on the main virulence factors characterizing Helicobacter pylori strains. Several pathogenic factors are important for the establishment and maintenance of H. pylori infection. Among those present in all isolates are the production of urease and phospholipases, the presence of flagella, the ability to attract neutrophils, the expression of iceA gene and a number of adhesins that ensure tissue-specific colonization. In addition, a subset of H. pylori strains is characterized by: i) a potent toxin (VacA) able to cause vacuolar degeneration of target cells by interfering with intracellular membrane fusion; and ii) the pathogenicity island (PAI), named CagPAI that encodes for a putative secretory mechanism in which the cagA gene encodes an immunodominant antigen that is associated with cytotoxin expression. [ABSTRACT FROM AUTHOR]

Biliary stent blockage represents the main limitation of the use of such devices in relieving obstructive jaundice due to a variety of malignant and benign conditions. Microbiological and morphological analysis of the occluding sludge present on the inner surface of 30 biliary stents was performed to evaluate the different components of such material and the effect of the antibiotic treatment on the biofilm formation. A highly organized biofilm, constituted by microbial cells embedded in an amorphous matrix together with crystallized bile salts, was observed Enterococcus spp. represented the most common isolate from both occluded and non-occluded stents. The antibiotic therapy, while selecting for multi-resistant bacteria and fungi, might possibly delay the biofilm formation. [ABSTRACT FROM AUTHOR]

Biofilms formed by multidrug-resistant bacteria are a major cause of hospital-acquired infections. Cold atmospheric-pressure plasma (CAP) is attractive for sterilization, especially to disrupt biofilms formed by multidrug-resistant bacteria. However, the underlying molecular mechanism is not clear. In this study, CAP effectively reduced the living cells in the biofilms formed by methicillin-resistant Staphylococcus aureus, and 6 min treatment with CAP reduced the S. aureus cells in biofilms by 3.5 log10. The treatment with CAP caused the polymerization of SaFtsZ and SaClpP proteins in the S. aureus cells of the biofilms. In vitro analysis demonstrated that recombinant SaFtsZ lost its self-assembly capability, and recombinant SaClpP lost its peptidase activity after 2 min of treatment with CAP. Mass spectrometry showed oxidative modifications of a cluster of peaks differing by 16 Da, 31 Da, 32 Da, 47 Da, 48 Da, 62 Da, and 78 Da, induced by reactive species of CAP. It is speculated that the oxidative damage to proteins in S. aureus cells was induced by CAP, which contributed to the reduction of biofilms. This study elucidates the biological effect of CAP on the proteins in bacterial cells of biofilms and provides a basis for the application of CAP in the disinfection of biofilms. [ABSTRACT FROM AUTHOR]

Fungal infections are increasing in prevalence worldwide, especially in immunocompromised individuals. Given the emergence of drug-resistant fungi and the fact that there are only three major classes of antifungal drugs available to treat invasive fungal infections, there is a need to develop alternative therapeutic strategies effective against fungal infections. Candida albicans is a commensal of the human microbiota that is also one of the most common fungal pathogens isolated from clinical settings. C. albicans possesses several virulence traits that contribute to its pathogenicity, including the ability to form drug-resistant biofilms, which can make C. albicans infections particularly challenging to treat. Here, we explored red, green, and blue visible lights alone and in combination with common photosensitizing compounds for their efficacies at inhibiting and disrupting C. albicans biofilms. We found that blue light inhibited biofilm formation and disrupted mature biofilms on its own and that the addition of photosensitizing compounds improved its antibiofilm potential. Red and green lights, however, inhibited biofilm formation only in combination with photosensitizing compounds but had no effects on disrupting mature biofilms. Taken together, these results suggest that photodynamic therapy may be an effective non-drug treatment for fungal biofilm infections that is worthy of further exploration. [ABSTRACT FROM AUTHOR]

Ceramic roof tiles are widespread marketed building materials, rapidly colonized by microorganisms that form multispecies biofilms on their surface and play crucial roles in biodeterioration processes. Coating tiles with water repellents is a pervasive industrial strategy employed to prevent liquid water penetration and slow biodeterioration. Very few studies have examined the links between the characteristics of water-repellent coatings and biofilm colonization patterns. Our work aims to compare the effects of coating tiles with two common water repellents (siliconate and siloxane) on the growth of colonizing microbes. We combined in situ exposure of tiles for over six years and macroscopic and microscopic observations with in vitro biotests, relying on the use of algal and fungal models. Our data showed that (1) tiles coated with water repellents were macroscopically less colonized by lichens (2) a significant fungal biofilm development at the microscopic scale (3) water repellents had very contrasting effects on our model strains. These data reinforce the great interest for industry to conduct more studies linking the nature of the water repellents with the composition of colonizing multispecies biofilms. The long-term objective is to improve the available water repellents and better adapt their selection to the nature of microbial colonization. [ABSTRACT FROM AUTHOR]