Vanessa Silva1,2,3,4, H Sofia Antão5, João Guimarães5, Justina Prada1,6, Isabel Pires1,7, Ângela Martins7, Luís Maltez1,6, José E Pereira1,6, José L Capelo8,9, Gilberto Igrejas2,3,4, Patrícia Poeta1,4. 1. Microbiology and Antibiotic Resistance Team (MicroART), Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal. 2. Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal. 3. Functional Genomics and Proteomics Unit, University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal. 4. Associated Laboratory for Green Chemistry (LAQV-REQUIMTE), University NOVA of Lisboa, Lisboa, Caparica, Portugal. 5. Angelini, Medical Department, C. Quebrada-Dafundo, Portugal. 6. CECAV, Vila Real, Portugal. 7. Department of Zootechnics, University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal. 8. BIOSCOPE Group, LAQV@REQUIMTE, Chemistry Department, Faculty of Science and Technology, NOVA University of Lisbon, Almada, Portugal. 9. Proteomass Scientific Society, Costa de Caparica, Portugal.
Abstract
OBJECTIVES: The aim of this study was to evaluate the efficacy of dalbavancin against MRSA biofilm-related infection in orthopaedic implants in vivo. METHODS: One MRSA strain isolated from human osteomyelitis was used to promote biofilm formation on the surface of screws. The implants were inserted in the proximal tibia under general anaesthesia. Thirty-nine Wistar rats were divided into three groups [control group (no treatment), Group 1 (7 days of treatment) and Group 2 (14 days of treatment)]; both treatment groups were administered dalbavancin intraperitoneally and euthanized after treatment. cfu of bacteria present in both the tibia and the implant were quantified. The infection severity was assessed by histopathology and scored from 0 (no infection) to 4 (severe infection). RESULTS: The high number of cfu/g and cfu/mL present in the control group indicated a well-established infection. There was a significant reduction in cfu in rats treated with dalbavancin both in the tibia (2.8 × 105 cfu/g) and the implant (1.1 × 106 cfu/mL) in Group 1 (1.8 × 103 cfu/g and 2.4 × 105 cfu/mL, respectively) and in Group 2 (8.2 cfu/g and 8.2 × 103 cfu/mL, respectively). Most animals from the control group presented an infection scored as 3 (severe). At the end of the experiment, most rats from Groups 1 and 2 presented an infection scored as 2 (moderate) and 0 (no infection), respectively. CONCLUSIONS: Although there was a marked decrease in cfu number, signs of biofilm-induced infection prevailed after 14 days of treatment. Further studies should be carried out to evaluate the potential of dalbavancin in the treatment of bone and orthopaedic implant-associated MRSA infections.
OBJECTIVES: The aim of this study was to evaluate the efficacy of dalbavancin against MRSA biofilm-related infection in orthopaedic implants in vivo. METHODS: One MRSA strain isolated from humanosteomyelitis was used to promote biofilm formation on the surface of screws. The implants were inserted in the proximal tibia under general anaesthesia. Thirty-nine Wistar rats were divided into three groups [control group (no treatment), Group 1 (7 days of treatment) and Group 2 (14 days of treatment)]; both treatment groups were administered dalbavancin intraperitoneally and euthanized after treatment. cfu of bacteria present in both the tibia and the implant were quantified. The infection severity was assessed by histopathology and scored from 0 (no infection) to 4 (severe infection). RESULTS: The high number of cfu/g and cfu/mL present in the control group indicated a well-established infection. There was a significant reduction in cfu in rats treated with dalbavancin both in the tibia (2.8 × 105 cfu/g) and the implant (1.1 × 106 cfu/mL) in Group 1 (1.8 × 103 cfu/g and 2.4 × 105 cfu/mL, respectively) and in Group 2 (8.2 cfu/g and 8.2 × 103 cfu/mL, respectively). Most animals from the control group presented an infection scored as 3 (severe). At the end of the experiment, most rats from Groups 1 and 2 presented an infection scored as 2 (moderate) and 0 (no infection), respectively. CONCLUSIONS: Although there was a marked decrease in cfu number, signs of biofilm-induced infection prevailed after 14 days of treatment. Further studies should be carried out to evaluate the potential of dalbavancin in the treatment of bone and orthopaedic implant-associated MRSA infections.