title: Visualisation of bacterial sequestration and bactericidal activity within hydrating Hydrofiber wound dressings.
abstract: The fluid handling and microbiological properties of a non-antimicrobial Hydrofiber(NAH) wound dressing have been compared with those of a silver salt-containing Hydrofiber (SCH). Fluorescent dyes (BacLight, Live/Dead Kit) were added to fresh cultures of two wound pathogens (Pseudomonas aeruginosa and Staphylococcus aureus), and used to visualise their viability. Live bacteria stained green and dead/dying bacteria turned red. When inoculated into samples of the NAH and SCH dressings, the viability of the bacteria could be effectively monitored over time using a rapid form of confocal laser scanning microscopy (RCLSM--Leica UK). When the NAH dressing was hydrated with stained bacterial culture, its fibres swelled quickly, reducing interstitial spaces between the fibres, resulting in the formation of a cohesive gel. Bacteria became immobilised in the gel, forming characteristic clumps, but remained largely green (viable) for more than 20 h with no apparent increase in numbers. The SCH initially behaved in a similar manner, however, using 3-D data from RCLSM time-lapse sequences P. aeruginosa was observed to turn progressively red (i.e. died) within 1.5-3 h and S. aureus similarly turned red within 5-7 h of contact with the SCH dressing. The ability of both Hydrofiber dressings to sequester and immobilise potentially pathogenic wound micro-organisms has been demonstrated. Additionally the SCH dressing was shown to kill immobilised bacteria, as a consequence of the ionic silver bactericide. These properties of the Hydrofiber dressings may contribute to providing an environment that is supportive to wound healing.
authors.affiliation: Medical Microscopy Sciences, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.
authors.forename: Geoffrey R
authors.initials: GR
authors.lastname: Newman
authors.forename: Michael
authors.initials: M
authors.lastname: Walker
authors.forename: Jan A
authors.initials: JA
authors.lastname: Hobot
authors.forename: Philip G
authors.initials: PG
authors.lastname: Bowler
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D047070:Bandages, Hydrocolloid / Q000382:microbiology*; D018441:Biofilms / Q000187:drug effects; D016503:Drug Delivery Systems / Q000379:methods; D019544:Equipment Failure Analysis / Q000379:methods; D008422:Materials Testing / Q000379:methods; D018613:Microscopy, Confocal / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods; D011550:Pseudomonas aeruginosa / Q000166:cytology* / Q000187:drug effects*; D012834:Silver / Q000008:administration & dosage* / Q000737:chemistry; D013211:Staphylococcus aureus / Q000166:cytology* / Q000187:drug effects*; D014867:Water / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D014867:Water; D012834:Silver