Efficacy of antiseptics in a novel 3-dimensional human plasma biofilm model (hpBIOM)

Abstract

The increasing incidence of non-healing wounds constitutes a pivotal socio-economic burden. 60-80% of chronic wounds are colonized by pathogenic microorganisms within a protective extracellular polymeric substance, bearing a great challenge in wound management. Human plasma was used to prepare the biofilm model (hpBIOM), adding pathogens to the plasma and forming Coagulalike discs with integrated pathogens were produced. The antiseptics Octenisept and Lavasorb were tested regarding their antibacterial properties on clinically relevant biofilm-growing bacteria (MRSA, P. aeruginosa) in the hpBIOM. Biofilm-typical glycocalyx-formation was confirmed using immunohistochemical staining. Treatment of a 12 h-maturated biofilm with Octenisept resulted in complete eradication of P. aeruginosa and MRSA after 48 h. Lavasorb proved less effective than Octenisept in this setting. In more mature biofilms (24 h), both antiseptics showed a delayed, partially decreased efficacy. Summarized, the hpBIOM provides essential factors for a translational research approach to be used for detailed human biofilm analyses and evaluation of antimicrobial/-biofilm properties of established and novel therapeutic strategies and products. Octenisept and Lavasorb showed an attenuated efficacy in the hpBIOM compared to planktonic conditions and previously published biofilm-studies, prompting the question for the necessity of introducing new international standards and pre-admission requirements on a translational base.

Anti-biofilm activity of antimicrobial hypochlorous wound irrigation solutions compared to common wound antiseptics and bacterial resilience in an innovative in-vitro human plasma biofilm model (hpBIOM)

“…Naturally, these results should be translated to clinical practice with caution, since certain limitations such as the use of mono-species biofilms and relatively short maturation times (12h) still apply. However, more mature and multi-species biofilms would exhibit even higher bacterial resilience, as partly already demonstrated in another work of our research group(11) and therefore pose an even greater challenge for hypochlorous irrigation solutions. The anti-biofilm capacities of such wound irrigation solutions are therefore quite limited making them rather suited for decontamination and decolonisation of acute and chronic wounds and prevention of re-contamination/-infection, rather than primary treatment of mature biofilms compared to high potency antiseptics.…”

“…5a-c). Compared to other approaches (11), no re-application of test-substances within 72 h was performed, demonstrating a certain remanence effect of OCT/PE and PHMB. In contrast to our earlier publication (12), hypochlorous agents not only failed to reduce microbial counts in biofilms but also in the here used planktonic method (QSM; Fig.…”

“…The development of our human plasma biofilm model (hpBIOM; Fig. 4a-c) (10,11), aims to narrow the gap between in-vitro and in-vivo biofilm research and provide a translational approach. The use of a complex biofilm model based on human material, including plasma and active immune cells, addresses the interactions of microbial biofilms with the human wound environment (3,14) as well as the relevant efficacy loss of antimicrobials under challenge (23,24), providing a 'close-to-reality' test scenario.…”

“…The development and use of the hpBIOM has been described in detail elsewhere (10,11) and was adapted to fit the specific agents and purpose pursued here. In brief, human plasma preserves (citrate buffered) and buffy coat from anonymous donors were obtained from the DRK-Blutspendedienst West (Hagen, Germany).…”

“…with high-protein, organic challenge as well as the human immune system need to be considered. Therefore, our research group developed an innovative human plasma biofilm model (hpBIOM) for quantifiable testing of anti-biofilm activity of antimicrobial and antiseptic agents in a challenging wound biofilm environment, closely resembling the in-vivo situation (10,11).…”