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· DOS Abstracts
Microcalorimetric detection of staphylococcal bio-
film growth on various prosthetic biomaterials af-
ter exposure to daptomycin
Christen Ravn, Inês Santos Ferreira, Elena Maiolo, Søren Overgaard, Andrej
Trampuz
Orthopaedic Research Unit and Dep. of Orthopaedic Surgery, University of
Southern Denmark and Odense University Hospital; Research Institute for
Medicines, Faculty of Pharmacy, Universidade de Lisboa, Portugal; Center for
Musculoskeletal Surgery, Charité - University Medicine Berlin, Berlin, Germa-
ny; Orthopaedic Research Unit and Dep. of Orthopaedic Surgery, University of
Southern Denmark and Odense University Hospital; Center for Musculoskeletal
Surgery, Charité - University Medicine Berlin, Berlin, Germany
Background:
Prosthetic joint infection involves bacterial biofilm formation.
Purpose / Aim of Study:
Primary aim of this in vitro study was to test the ef-
ficacy of daptomycin to eradicate staphylococcal biofilms on various orthopedic
implant surfaces and materials. Secondary aim was to quantitatively estimate
the formation of staphylococcal biofilm.
Materials and Methods:
We tested six clinically important biomaterials: cobalt
chrome alloy, pure titanium, grid-blasted titanium, porous plasma-coated tita-
nium with/without hydroxyapatite, and polyethylene. Biofilms of S. aureus and
S. epidermidis were formed on the samples and thereafter exposed to dapto-
mycin. Samples were subsequently sonicated in order to detect dislodged bio-
film bacteria and transferred to a microcalorimeter for real-time measurement
of growth related heat flow. Minimal biofilm eradication concentration (MBEC)
was determined as the lowest concentration (mg/L) of daptomycin required
to eradicate the biofilm bacteria on the sample. The time (hours) to detection
expressed as the heat flow >50 µW (TTD- 50) indirectly quantifies the initial
amount of biofilm bacteria, with a shorter TTD-50 representing a larger amount
of bacteria.
Findings / Results:
Median MBEC of S. aureus biofilm on smooth metallic
surfaces was significantly lower than the rough metallic surfaces. Variations of
MBEC in experiments with S. epidermidis biofilms on test samples with smooth
or rough surface was found non-significant. Mean TTD-50 of S. aureus biofilms
on rough metallic samples was significantly lower than smooth metallic samples
and polyethylene. Mean TTD-50 with S. epidermidis biofilm on smooth metals
was also significantly higher than their rough counterparts.
Conclusions:
Growth of biofilm bacteria on orthopedic materials are variably
influenced by exposure to the potent antimicrobial effect of high-dose dapto-
mycin.
No conflicts of interest reported
130.