Copal Bone Cement Is More Effective in Preventing Biofilm Formation than Palacos R-G

Abstract

Bone cements loaded with combinations of antibiotics are assumed more effective in preventing infection than bone cements with gentamicin as a single drug. Moreover, loading with an additional antibiotic may increase interconnectivity between antibiotic particles to enhance release. We hypothesize addition of clindamycin to a gentamicin-loaded cement yields higher antibiotic release and causes larger inhibition zones against clinical isolates grown on agar and stronger biofilm inhibition. Antibiotic release after 672 hours from Copal bone cement was more extensive (65% of the clindamycin and 41% of the gentamicin incorporated) than from Palacos R-G (4% of the gentamicin incorporated). The higher antibiotic release from Copal resulted in a stronger and more prolonged inhibition of bacterial growth on agar. Bacterial colony counting and confocal laser scanning microscopy of biofilms grown on the bone cements suggest antibiotic release reduced bacterial viability, most notably close to the cement surface. The gentamicin-sensitive Staphylococcus aureus formed gentamicin-resistant small colony variants on Palacos R-G and therefore Copal more effectively decreased biofilm formation than Palacos R-G.

Sufficient Release of Antibiotic by a Spacer 6 Weeks after Implantation in Two-stage Revision of Infected Hip Prostheses

“…Second, we studied only several antibiotics and only one type of cement. Copal cement was used because antibiotic release from Copal of both antibiotics is greater and more prolonged and Copal is more effective in biofilm reduction than Palacos R-G cement or other cement [6,27]. The data we obtained with the antibiotics we studied are not necessarily relevant for other mixtures of antibiotics.…”

“…Based on the recommendations of the microbiologist, who specializes in periprosthetic infections, Copal bone cement was used for the spacer (seven cases), with gentamicin and clindamycin already mixed in during manufacturing (Heraeus Medical) if the microorganism was sensitive against gentamicin and clindamycin and because of the synergistic effect on the release of each antibiotic [6]. If the pathogens were resistant to one of these antibiotics, an extra 2 g vancomycin was added to 40 g Copal cement during the operation (seven cases).…”

“…If the pathogens were resistant to one of these antibiotics, an extra 2 g vancomycin was added to 40 g Copal cement during the operation (seven cases). Copal cement was still used in these cases because antibiotic release from Copal of both antibiotics is prolonged and Copal is more effective in biofilm reduction compared with Palacos R-G or other cement [6,27].…”

“…Thus, one cannot make assumptions about one antibiotic based on evidence from another. One study recommends using Copal bone cement rather than Palacos for the spacers because of the former's ability to release higher amounts of antibiotic [6]. Other antibiotics sometimes are added to it according to the determined antibiotic sensitivity of the pathogen concerned, although this usually is vancomycin [6,9].…”

“…One study recommends using Copal bone cement rather than Palacos for the spacers because of the former's ability to release higher amounts of antibiotic [6]. Other antibiotics sometimes are added to it according to the determined antibiotic sensitivity of the pathogen concerned, although this usually is vancomycin [6,9]. By adhering to this concept, a 100% rate of infection control has been achieved [10,20].…”