The human intestinal epithelium is formed by a single layer of epithelial cells that separates the intestinal lumen from the underlying lamina propri

Summary: F aecalibacterium prausnitzii , an abundant member of the human commensal microbiota, has been proposed to have a protective role in the intestine. However, it is an obligate anaerobe, difficult to co‐culture in viable form with oxygen‐requiring intestinal cells. To overcome this limitation, a unique apical anaerobic model of the intestinal barrier, which enabled co‐culture of live obligate anaerobes with the human intestinal cell line C aco‐2, was developed. C aco‐2 cells remained viable and maintained an intact barrier for at least 12 h, consistent with gene expression data, which suggested C aco‐2 cells had adapted to survive in an oxygen‐reduced atmosphere. Live F. prausnitzii cells, but not ultraviolet ( UV )‐killed F . prausnitzii , increased the permeability of mannitol across the epithelial barrier. Gene expression analysis showed inflammatory mediators to be expressed at lower amounts in C aco‐2 cells exposed to live F . prausnitzii than UV ‐killed F . prausnitzii , This, consistent with previous reports, implies that live F . prausnitzii produces an anti‐inflammatory compound in the culture supernatant, demonstrating the value of a physiologically relevant co‐culture system that allows obligate anaerobic bacteria to remain viable.

Staphylococcus aureus in biofilms is highly resistant to the treatment with antibiotics, to which the planktonic cells are susceptible. This is likely to be due to the biofilm creating a protective barrier that prevents antibiotics from accessing the live pathogens buried in the biofilm. S. aureus biofilms consist of an extracellular matrix comprising, but not limited to, extracellular bacterial DNA (eDNA) and poly-β-1, 6-N-acetyl- d -glucosamine (PNAG). Our study revealed that despite inferiority of dispersin B (an enzyme that degrades PNAG) to DNase I that cleaves eDNA, in dispersing the biofilm of S. aureus , both enzymes were equally efficient in enhancing the antibacterial efficiency of tobramycin, a relatively narrow-spectrum antibiotic against infections caused by gram-positive and gram-negative pathogens, including S. aureus , used in this investigation. However, a combination of these two biofilm-degrading enzymes was found to be significantly less effective in enhancing the antimicrobial efficacy of tobramycin than the individual application of the enzymes. These findings indicate that combinations of different biofilm-degrading enzymes may compromise the antimicrobial efficacy of antibiotics and need to be carefully assessed in vitro before being used for treating medical devices or in pharmaceutical formulations for use in the treatment of chronic ear or respiratory infections.