Laboratory Research
To determine the effect of continuous Topical Oxygen Therapy (cTOT) on biofilm gene expression in Pseudomonas aeruginosa using a customized molecular assay.
Methods:
Sterilized porcine skin explants were inoculated with P. aeruginosa in triplicate (0h negative control, 24h cTOT on, 24h cTOT off). The oxygen delivery system (ODS) of the cTOT device was applied to the inoculated tissue and covered with a semi-occlusive dressing. All samples were incubated at 37°C ± 2°C for 24h with the negative control 0h inoculated porcine skin samples recovered immediately.
Planktonic suspensions and biopsy samples were removed at 0 and 24h. Samples were processed and quantifiably assessed using gene specific RT-qPCR assays for a panel of eight P. aeruginosa genes (16S, pelA pslA, rsaL, pcrV, psqC, acpP, cbrA) associated with biofilm and quorum, protein secretion/translocation and metabolism.
Results: Transcriptional up-regulation of pelA, pcrV and acpP, responsible for intracellular adhesion, needletip protein production for type-3 secretion systems and fatty acid synthesis during proliferation, respectively, was observed when the cTOT device was switched on compared to when the device was switched off.
Discussion: Data suggests increased metabolic activity within bacterial cells following cTOT treatment. Oxygen has previously been shown to increase susceptibility of biofilms to antibiotics5 through enhancing metabolism. cTOT is an adjunctive therapy that supports faster healing1–3 and pain reduction4 in non-healing hypoxic wounds. Observed gene expression changes here highlight the impact of cTOT on biofilms potentially influencing antimicrobial treatment success in wounds warranting further in-vitro and clinical investigation.