Radial Extracorporeal Shock Wave Therapy against Cutibacterium acnes Implant-Associated Infections: An in Vitro Trial

Abstract

Background: Antibiotic management of low-virulent implant-associated infections induced by Cutibacterium acnes may be compromised by multi-drug resistance development, side effects, and increased cost. Therefore, we sought to assess the effects of shock wave therapy against the above pathogen using an in vitro model of infection. Methods: We used a total of 120 roughened titanium alloy disks, simulating orthopedic biomaterials, to assess the results of radial extracorporeal shock wave therapy (rESWT) against C. acnes (ATCC 11827) biofilms relative to untreated control. In particular, we considered 1.6 to 2.5 Bar with a frequency ranging from 8–11 Hz and 95 to 143 impulses per disk to investigate the antibacterial effect of rESWT against C. acnes planktonic (free-floating) and biofilm forms. Results: Planktonic bacteria load diminished by 54% compared to untreated control after a 1.8-bar setting with a frequency of 8 Hz and 95 impulses was applied (median absorbance (MA) for intervention vs. control groups was 0.9245 (IQR= 0.888 to 0.104) vs. 0.7705 (IQR = 0.712 to 0.864), respectively, p = 0.001). Likewise, a statistically significant reduction in the amount of biofilm relative to untreated control was documented when the above setting was considered (MA for treatment vs biofilm control groups was 0.244 (IQR= 0.215–0.282) and 0.298 (IQR = 0.247–0.307), respectively, p = 0.033). Conclusion: A 50% biofilm eradication was documented following application of low-pressure and low-frequency radial shock waves, so rESWT could be investigated as an adjuvant treatment to antibiotics, but it cannot be recommended as a standalone treatment against device-associated infections induced by C. ances.

In vitro laboratory infection research in orthopaedics: Why, when, and how

“…Pictorial and graphical presentation of the results is essential: Regarding infection-related in vitro pre-clinical research, it is proposed that the authors produce a graphical representation of microbial development that will serve as the basis for their future tests[ 9 ] (Figure 1 ).…”

“…In doing so, the credibility of the work and the establishment of future, more advanced and sophisticated investigations can be improved. Furthermore, in case of comparisons with control groups, implementation of a dedicated piece of software such as Prism (GraphPad Software, Inc, La Jolla, CA, United States) is advocated to generate scientifically sound figures[ 9 ] (Figure 2 ).…”