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German Congress of Orthopaedics and Traumatology (DKOU 2022)

25. - 28.10.2022, Berlin

Testing of bone cement with gentamicin against Staphylococcus aureus infections in Galleria mellonella

Meeting Abstract

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  • presenting/speaker Gopala Krishna Mannala - Klinik und Poliklinik für Unfallchirurgie, Regensburg, Germany
  • Markus Rupp - Klinik und Poliklinik für Unfallchirurgie, Regensburg, Germany
  • Volker Alt - Klinik und Poliklinik für Unfallchirurgie, Regensburg, Germany

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2022). Berlin, 25.-28.10.2022. Düsseldorf: German Medical Science GMS Publishing House; 2022. DocAB41-1098

doi: 10.3205/22dkou283, urn:nbn:de:0183-22dkou2834

Published: October 25, 2022

© 2022 Mannala et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.


Outline

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Objectives: Galleria mellonella larvae is a well-known insect infection model that has been used to test the virulence of bacterial and fungal strains as well as for the high throughput screening of antimicrobial compounds against infections. It is also has been used as pre-clinical infection model to reduce the higher mammalian models in the development of antimicrobial compounds. Recently, we have developed insect infection model G. mellonella larvae to study implant associated bacterial biofilm infections using small K-wire as implant material. Here, weaimed to further expand the use of G. mellonella to test other materials such as bone cement with combination of gentamicin to treat implant-associated infections.

Methods: G. mellonella larvae are maintained at 30°C on artificial diet in an incubator. The poly methyl methacrylate (PMMA) with and without gentamicin and liquid methyl methacrylate (MMA) were kindly provided by Heraeus Medical GmbH, Wehrheim. To make the bone cement implants as cubes, Teflon plate (Karl Lettenbauer, Erlangen) with specified well size was used. The Radiopaque polymer and monomer were mixed well in a bowl, applied over on to the Teflon plate and pressed with spatula to form fine and uniform cubes. After polymerization, the bone cement implants were taken out of the Teflon well plate with the help of pin. For the infection process, bone cement cubes were pre-incubated with S. aureus EDCC 5055 culture at 5x106 CFU/ml for 30 min at 150 rpm shaking conditions. Later, these implants were washed with 10ml PBS and implanted in the larvae as mentioned. Survival of the larvae were observed at 37°C in an incubator. To analyze the susceptibility of the bacterial infections towards gentamicin, survival ofthe larvae compared with control group implanted only with bone cement. The effect of gentamicin was also measured in terms of S. aureus load in larvae on 2nd day. SEM analysis was performed to see the effect of gentamicin on biofilm formation on bone cement.

Results and conclusion: Our experiments established the G. mellonella as an excellent model to screen bone cement with antimicrobial compounds against bacterial infections.The gentamicin bone cement samples showed excellent S. aureus bacterial load reduction after the implantation in G. mellonella model. The bone cement with gentamicin showed better survival of larvae infected with S. aureus compared to control. Finally, the gentamicin also affected the biofilm formation on the bone cement surface with S. aureus. Thus, G. mellonella can be used as rapid and economical pre-clinical model to study the bone cement associate bacterial infections as well as screening of the various antimicrobial compounds.