Biofilms in skin infections: Propionibacterium acnes and acne vulgaris.

It is generally accepted that many human infections are biofilm-related and that sessile (biofilm-grown) cells are highly resistant against antimicrobial agents. Propionibacterium acnes plays a role in the pathogenesis of acne vulgaris, a common disorder of the pilosebaceous follicles and it has been suggested that P. acnes cells residing within the follicles grow as a biofilm. Although P. acnes biofilms have not been observed directly in the pilosebaceous unit, the observation that P. acnes readily forms biofilm in vitro as well as on various medical devices in vivo, combined with the high resistance of sessile P. acnes cells and the increased production of particular virulence factors and qourum sensing molecules in sessile cells point in this direction. In addition, in vitro and in vivo biofilm formation has also been demonstrated for other microorganisms involved in skin diseases (including Staphylococcus aureus and Streptococcus pyogenes).

Use of the modified robbins device and fluorescent staining to screen plant extracts for the inhibition of S. mutans biofilm formation.

Streptococcus mutans plays an important role in the formation of dental plaque. To study biofilm growth on hydroxyapatite (HA) in vitro, a flow system based on a Modified Robbins Device (MRD) and a method for the quantification of the biomass using fluorescent staining with SYTO(R) 9 were developed. The combined approach was used to assess the inhibitory effect of plant extracts on biofilm formation in concentrations below their minimal inhibitory concentrations.

Recurrent colonization of successively implanted tracheoesophageal vocal prostheses by a member of the Fusarium solani species complex.

Tracheoesophageal vocal prostheses (TVP) in laryngectomized patients commonly deteriorate due to overgrowth by yeasts, particularly Candida species. We describe the first case of colonization of such devices by a member of the Fusarium solani species complex in a patient with a history of glottal carcinoma. Three isolates, from three prostheses, were found morphologically consistent with the traditional picture of F. solani. Ribosomal sequence analysis showed that the isolates belonged to a distinct, as yet apparently unnamed phylogenetic species within the F. solani species complex. This species, one of two distinct genetic types (genotype 2) traditionally considered part of the plant-pathogenic subtaxon Fusarium solani f. sp. radicicola, has not previously been identified as an agent of human or animal disease, although it is closely related to a known etiologic agent of mycetoma, an Acremonium-like species recently renamed Fusarium falciforme. Sequence and multisatellite M13 polymorphism analysis revealed no distinctions among the case isolates. Production of cyclosporine was detected for all three case isolates.