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Preventing Orthopaedic Implant-Associated Infections: the Sheep as an Animal Model
J. Comp. Path. 2016, Vol. 154, 58e123
ESVP, ECVP and NSVP Proceedings 2015
PREVENTING ORTHOPAEDIC IMPLANT-ASSOCIATED INFECTIONS: THE SHEEP AS AN ANIMAL MODEL M. Gimeno *, P. Pinczowski *, F.J. V azquez *, M. P erez y, an* J. Asın *, J. Santamarıa z, M. Arruebo z and L. Luj *Department of Animal Pathology, yDepartment of Anatomy, Embryology and Genetics and zDepartment of Chemical Engineering, Aragon Institute of Nanoscience (INA), University of Zaragoza, Spain Introduction: The ovine model is a well-accepted large animal model for in-vivo biomedical studies, especially in orthopaedic research. Sheep are useful for addressing the biomechanical, clinical and histological processes of bone due to their similarities with human weight, size, structure and remodelling process. We present two invivo experiments using different orthopaedic devices for controlled antibiotic release to prevent orthopaedic implant-associated infections. Both implants were previously studied in vitro in order to evaluate the antibiotic release kinetics. Those systems are presented as a potential use in drug-eluting fixation implants for orthopaedic applications. Materials and Methods: Two new hollow antibiotic-loaded implants, (A) macroporous stainless steel loaded with linezolid and (B) stainless steel with several orifices drilled in the reservoir wall loaded with cefazolin, were used in two different experiments. Control animals without antibiotic implants were used in both experiments. Implants were placed into the tibia. Implant A was placed into five sheep and implant B was used in nine sheep. All animals were trans-surgically experimentally infected with the ATCC 6538 strain of Staphylococcus aureus. Clinical follow up was performed daily. Animals were killed at 3, 7 or 9 days post infection (dpi) and tissues were studied by pathological and microbiological means. Results: After 3, 7 and 9 dpi, sheep with both A and B antibioticloaded implants did not show any evidence of infection, while control animals showed local and systemic changes compatible with infection and inflammation. Conclusions: These results demonstrate the efficiency of both antibiotic-loaded implants in preventing infection in orthopaedic devices.
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MAEDI-VISNA: AN EXPERIMENTAL STUDY ON THE DISTRIBUTION OF TWO VIRAL STRAINS WITH DIFFERENT TISSUE ORIGINS USING THE INTRATRACHEAL ROUTE OF INFECTION P. Pinczowski *, L. Sanjos e y, M. Gimeno *, J. Asın *, erez *, D. de Andr es y, J.J. Badiola *, L. de Pablo y, M. P y y an* B. Amorena , R. Reina and L. Luj *University of Zaragoza and yAgrobiotechnology Institute (CSIC/UPNA) Navarra, Spain Introduction: Maedi-visna (MV) infection causes lesions in the lungs, CNS, joints and mammary gland. Two autochthonous strains have been isolated previously from field cases in which neurological and articular presentations were the predominant clinical forms. The aim of this work was to study the organ distribution and pathogenesis of the different clinical forms, following intratracheal infection using those strains. Materials and Methods: Twenty male, Rasa Aragonesa breed lambs, negative by ELISA and PCR for MV, were split in two groups of eight animals and a control group of four animals. Groups were infected intratracheally twice (0 and 319 dpi), either with the neural strain (group A) or the articular strain (group B). The control group was mock infected. Animals were evaluated by ELISA and PCR weekly. Two animals from each group and one control were killed at 134, 273 and 319 dpi. Results: Serology or PCR confirmed infection in all infected animals. The absorbance in ELISA was greater in samples from group B animals. The specific viral strain was observed in each group. Most animals from group B had significant lesions in the lung and carpal joints, while a few animals from group A had lesions only in the lung. Microscopically, all infected animals had pulmonary lesions compatible with MV and all animals from group B had MV lesions in the carpal joints. The 496 strain was detected by qPCR in the carpal joints of the majority of animals from group B. Conclusions: The articular strain showed more virulent behaviour and reproduced the arthritic lesions, confirming its original tropism.
ESVP, ECVP and NSVP Proceedings 2015
PREVENTING ORTHOPAEDIC IMPLANT-ASSOCIATED INFECTIONS: THE SHEEP AS AN ANIMAL MODEL M. Gimeno *, P. Pinczowski *, F.J. V azquez *, M. P erez y, an* J. Asın *, J. Santamarıa z, M. Arruebo z and L. Luj *Department of Animal Pathology, yDepartment of Anatomy, Embryology and Genetics and zDepartment of Chemical Engineering, Aragon Institute of Nanoscience (INA), University of Zaragoza, Spain Introduction: The ovine model is a well-accepted large animal model for in-vivo biomedical studies, especially in orthopaedic research. Sheep are useful for addressing the biomechanical, clinical and histological processes of bone due to their similarities with human weight, size, structure and remodelling process. We present two invivo experiments using different orthopaedic devices for controlled antibiotic release to prevent orthopaedic implant-associated infections. Both implants were previously studied in vitro in order to evaluate the antibiotic release kinetics. Those systems are presented as a potential use in drug-eluting fixation implants for orthopaedic applications. Materials and Methods: Two new hollow antibiotic-loaded implants, (A) macroporous stainless steel loaded with linezolid and (B) stainless steel with several orifices drilled in the reservoir wall loaded with cefazolin, were used in two different experiments. Control animals without antibiotic implants were used in both experiments. Implants were placed into the tibia. Implant A was placed into five sheep and implant B was used in nine sheep. All animals were trans-surgically experimentally infected with the ATCC 6538 strain of Staphylococcus aureus. Clinical follow up was performed daily. Animals were killed at 3, 7 or 9 days post infection (dpi) and tissues were studied by pathological and microbiological means. Results: After 3, 7 and 9 dpi, sheep with both A and B antibioticloaded implants did not show any evidence of infection, while control animals showed local and systemic changes compatible with infection and inflammation. Conclusions: These results demonstrate the efficiency of both antibiotic-loaded implants in preventing infection in orthopaedic devices.
77
MAEDI-VISNA: AN EXPERIMENTAL STUDY ON THE DISTRIBUTION OF TWO VIRAL STRAINS WITH DIFFERENT TISSUE ORIGINS USING THE INTRATRACHEAL ROUTE OF INFECTION P. Pinczowski *, L. Sanjos e y, M. Gimeno *, J. Asın *, erez *, D. de Andr es y, J.J. Badiola *, L. de Pablo y, M. P y y an* B. Amorena , R. Reina and L. Luj *University of Zaragoza and yAgrobiotechnology Institute (CSIC/UPNA) Navarra, Spain Introduction: Maedi-visna (MV) infection causes lesions in the lungs, CNS, joints and mammary gland. Two autochthonous strains have been isolated previously from field cases in which neurological and articular presentations were the predominant clinical forms. The aim of this work was to study the organ distribution and pathogenesis of the different clinical forms, following intratracheal infection using those strains. Materials and Methods: Twenty male, Rasa Aragonesa breed lambs, negative by ELISA and PCR for MV, were split in two groups of eight animals and a control group of four animals. Groups were infected intratracheally twice (0 and 319 dpi), either with the neural strain (group A) or the articular strain (group B). The control group was mock infected. Animals were evaluated by ELISA and PCR weekly. Two animals from each group and one control were killed at 134, 273 and 319 dpi. Results: Serology or PCR confirmed infection in all infected animals. The absorbance in ELISA was greater in samples from group B animals. The specific viral strain was observed in each group. Most animals from group B had significant lesions in the lung and carpal joints, while a few animals from group A had lesions only in the lung. Microscopically, all infected animals had pulmonary lesions compatible with MV and all animals from group B had MV lesions in the carpal joints. The 496 strain was detected by qPCR in the carpal joints of the majority of animals from group B. Conclusions: The articular strain showed more virulent behaviour and reproduced the arthritic lesions, confirming its original tropism.