Development and application of a polymicrobial, in vitro, wound biofilm model

Abstract

Aims: The goal of this investigation was to develop an in vitro, polymicrobial, wound biofilm capable of supporting the growth of bacteria with variable oxygen requirements.Methods and Results: The strict anaerobe Clostridium perfringens was isolated by cultivating wound homogenates using the drip-flow reactor (DFR), and a three-species biofilm model was established using methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Cl. perfringens in the colony-drip-flow reactor model. Plate counts revealed that MRSA, Ps. aeruginosa and Cl. perfringens grew to 7·39 ± 0·45, 10·22 ± 0·22 and 7·13 ± 0.·77 log CFU per membrane, respectively. The three-species model was employed to evaluate the efficacy of two antimicrobial dressings, Curity™ AMD and Acticoat™, compared to sterile gauze controls. Microbial growth on Curity™ AMD and gauze was not significantly different, for any species, whereas Acticoat™ was found to significantly reduce growth for all three species.Conclusions: Using the colony-DFR, a three-species biofilm was successfully grown, and the biofilms displayed a unique structure consisting of distinct layers that appeared to be inhabited exclusively or predominantly by a single species.Significance and Impact of the Study: The primary accomplishment of this study was the isolation and growth of an obligate anaerobe in an in vitro model without establishing an artificially anaerobic environment.