Abiotrophia defectiva knee prosthesis infection: A case report

<p>Abstract</p> <p>Background</p> <p><it>Abiotrophia </it>species have rarely been implicated in osteoarticular infections. We report one case of an <it>A. defectiva </it>knee prosthesis infection.</p> <p>Case presentation</p> <p>A 71-year-old man of Italian origin presented with pain and swelling of the knee four years after the implantation of a total knee replacement prosthesis. While standard culturing of the synovial fluid resulted in no isolation of microorganisms, the direct inoculation of the synovial fluid into a rich culture medium resulted in the identification of <it>A. defectiva </it>by polymerase chain reaction sequencing. Repeated attempts of culturing microorganisms from blood were negative, and echocardiograms and colonoscopies were unremarkable. High-dose amoxicillin for nine months and a two-stage replacement of the knee prosthesis led to full patient recovery by the time of the 12-month follow-up examination.</p> <p>Conclusions</p> <p>Because <it>Abiotrophia </it>spp. are fastidious microorganisms, it is likely that cases of <it>Abiotrophia </it>orthopedic infection are misdiagnosed as culture-negative infections. Direct inoculation of synovial fluids into rich broth medium and further polymerase chain reaction-based detection of culture-negative synovial fluids are key tests for accurate documentation and detection of these infections.</p

The effect of vancomycin and tobramycin on the tensile properties of cured low viscosity bone cements

Samples of plain and vancomycin-tobramycin-loaded low viscosity cements were evaluated for their tensile mech. properties. Vancomycin is effective against nearly all resistant pathogens now involved in prosthesis infection. The mech. properties of vancomycin-impregnated cement have never been studied. Tobramycin extends the spectrum to Gram neg. bacteria and has been well studied as used in bone cement. This antibiotic mixt. covers most of the pathogens resulting from arthroplasty thus providing an active local prophylaxis against infection. Specimens of 4 low-viscosity bone cements were machined, radiographed and tested. The addn. of 2 g vancomycin in 40 g cement powder did not significantly affect the tensile properties of the four cements. Simultaneous addn. of vancomycin (2 g) and tobramycin (1 g) significantly decreased the tensile strength and fracture strain of one cement, but the abs. values remained equal to the others or higher and well above the levels reported with std. viscosity cements. Vancomycin-tobramycin fulfill the criteria required for diffusion and antimicrobial activity after admixing in bone cement. The effects of such a combination on the tensile properties of 4 low viscosity bone cements are acceptable. [on SciFinder (R)

The effect of vancomycin and tobramycin on the tensile properties of cured low viscosity bone cements

Samples of plain and vancomycin-tobramycin-loaded low viscosity cements were evaluated for their tensile mech. properties. Vancomycin is effective against nearly all resistant pathogens now involved in prosthesis infection. The mech. properties of vancomycin-impregnated cement have never been studied. Tobramycin extends the spectrum to Gram neg. bacteria and has been well studied as used in bone cement. This antibiotic mixt. covers most of the pathogens resulting from arthroplasty thus providing an active local prophylaxis against infection. Specimens of 4 low-viscosity bone cements were machined, radiographed and tested. The addn. of 2 g vancomycin in 40 g cement powder did not significantly affect the tensile properties of the four cements. Simultaneous addn. of vancomycin (2 g) and tobramycin (1 g) significantly decreased the tensile strength and fracture strain of one cement, but the abs. values remained equal to the others or higher and well above the levels reported with std. viscosity cements. Vancomycin-tobramycin fulfill the criteria required for diffusion and antimicrobial activity after admixing in bone cement. The effects of such a combination on the tensile properties of 4 low viscosity bone cements are acceptable. [on SciFinder (R)