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Influence of Sonication on Bacterial Regrowth from Antibiotic Loaded PMMA Scaffolds - An In-vitro Study
Martin Clauss1,2, Esther Laschkolnig3,4, Susanne Graf1,4
1Kantonsspital Baselland, Liestal, Interdisciplinary Unit for Orthopaedic Infections, Switzerland.
Abstract:
Periprosthetic joint infection (PJI) is one of the most challenging complications after joint replacement. However, when treated correctly, chances of recovery are good. The most important step in correct diagnosis and management of PJI is the detection of the causative germ. In the last years, the use of sonication in the diagnostic process has become more important. However, this diagnostic methodology has been controversially discussed when used in combination with antibiotic loaded bone cement (PMMA), which is frequently used in joint replacement surgeries. The aim of this study was thus to analyse in vitro bacterial growth in sonication fluid cultures obtained from antibiotic loaded PMMA which were contaminated with various bacterial biofilms. Sonication fluid obtained from antibiotic loaded PMMA (Copal G+V and Copal G+C) and plain Palacos R (control) contaminated either with S. aureus, E. faecalis, S. sanguinis or P.acnes, were analysed for bacterial re-growth in a standardised in-vitro setting. In vitro bacterial growth was not interfered by released antibiotics from sonication of antibiotic loaded PMMA for S. aureus, E. faecalis and S. sanguinis. However, for P. acnes bacterial counts were affected by the released antibiotics as well as by the time delay between sonication and analysis. The in-vitro data suggest sonication to be an easy and sensitive diagnostic modality to detect easy-to-detect bacteria, however, results are alarming for the difficult-to-detect bacteria P. acnes, indicating that further attention and research is necessary to improve the detection of difficult-to-detect bacteria.
Insights
Sonication effectively detects common bacteria in joint infections, but antibiotic-loaded bone cement may hinder detection of difficult bacteria like P. acnes. Further research is needed for improved diagnostics.
Area of Science:
- Orthopedic Surgery
- Infectious Diseases
- Microbiology
Background:
- Periprosthetic joint infection (PJI) is a significant complication following joint replacement surgery.
- Accurate diagnosis and management of PJI rely heavily on identifying the causative microorganisms.
- Sonication is an increasingly utilized diagnostic method for PJI, but its efficacy with antibiotic-loaded bone cement is debated.
Purpose of the Study:
- To evaluate the in vitro bacterial growth in sonication fluid from antibiotic-loaded bone cement contaminated with various bacterial biofilms.
- To assess the impact of antibiotics released from bone cement on bacterial regrowth after sonication.
- To determine the reliability of sonication for detecting different bacterial species in the context of PJI management.
Main Methods:
- Sonication fluids were obtained from antibiotic-loaded polymethyl methacrylate (PMMA) bone cement (Copal G+V, Copal G+C) and plain PMMA (control).
- Samples were intentionally contaminated with biofilms of Staphylococcus aureus, Enterococcus faecalis, Streptococcus sanguinis, and Propionibacterium acnes.
- Bacterial regrowth was analyzed in a standardized in vitro setting to assess the influence of released antibiotics and time delays.
Main Results:
- Bacterial regrowth of S. aureus, E. faecalis, and S. sanguinis was not significantly inhibited by antibiotics released from sonicated PMMA.
- Bacterial counts of P. acnes were affected by released antibiotics and the time interval between sonication and analysis.
- Sonication demonstrated effectiveness in detecting easily culturable bacteria but showed limitations for P. acnes.
Conclusions:
- Sonication is a sensitive diagnostic tool for common PJI-causing bacteria when used with antibiotic-loaded PMMA.
- The detection of difficult-to-detect bacteria, particularly P. acnes, may be compromised by antibiotic release and time delays.
- Further research is essential to optimize sonication protocols for improved detection of challenging pathogens in PJI.
