[Collagen hydroxyapatite (Healos) saturated with gentamicin or levofloxacin. In vitro antimicrobial effectiveness - a pilot study].
BACKGROUND
The functions of synthetic bone graft substitutes include not only structural support to provide bone healing and osseous ingrowth but also the ability to serve as a local antibiotic delivery system to prevent or treat infections of the spine.


METHODS
The impregnation and antibiotic efficiency of gentamicin and levofloxacin with Healos was investigated in vitro and compared with Healos without an antibiotic additive. These antibiotic-loaded bone graft substitutes were examined without dilution and with 10-fold and 100-fold dilution for activity against spondylodiscitis-causing bacteria on different agar plates using an agar diffusion method.


RESULTS
All hydroxyapatite (HA)/collagen-saturated diluted antibiotics showed elliptical inhibition zones on the corresponding agar plates. For both antibiotics, there was a linear correlation between dilution and area of the inhibition zone.


CONCLUSIONS
The analysis showed that the antimicrobial activity of HA/collagen-saturated antibiotics corresponded to the antimicrobial dilutions. These results should be further analyzed using in vivo studies to determine the remaining antibiotic efficiency after implantation of bone graft substitutes.
Fürstenberg
C H
CH
Querschnittzentrum und Wirbelsäulenchirurgie, Orthopädische Universitätsklinik, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Deutschland. carl.hans.fuerstenberg@ok.uni-heidelberg.de
Wiedenhöfer
B
B
Putz
C
C
Burckhardt
I
I
Gantz
S
S
Kleinschmidt
K
K
Schröder
K
K
D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D018786:Bone Substitutes; D003094:Collagen; D004305:Dose-Response Relationship, Drug; D017886:Durapatite; D004926:Escherichia coli / Q000187:drug effects*; D005839:Gentamicins / Q000008:administration & dosage*; D006801:Humans; D064704:Levofloxacin; D008826:Microbial Sensitivity Tests; D015242:Ofloxacin / Q000008:administration & dosage*; D010865:Pilot Projects; D013211:Staphylococcus aureus / Q000187:drug effects*; D013297:Streptococcus pyogenes / Q000187:drug effects*
D000900:Anti-Bacterial Agents; D018786:Bone Substitutes; D005839:Gentamicins; C509317:nano-hydroxyapatite-collagen; D064704:Levofloxacin; D003094:Collagen; D017886:Durapatite; D015242:Ofloxacin