The study aimed to evaluate a new gentamicin-vancomycin-impregnated (2:1) PMMA coating of an internal fixation device, miniaturized to be tested in a rabbit model of osteomyelitis, to treat bone and intramedullary infections. The device was implanted in rabbit femur, previously infected, and bacteriological, radiological and histologic investigations were performed at 7 weeks after bacterial inoculum. Osteomyelitis of the right femur was induced in general anaesthesia in 20 New Zealand male rabbits with 0.2 ml (total load 106 CFU) of methicillin-resistant Staphylococcus aureus (MRSA) in the femoral canal. Four weeks after inoculum, after debridement of the right femur canal, the animals were divided into 4 groups of 5 animals each and treated according to the following protocols: Group 1, insertion of a steel AISI316 intramedullary nail; Group 2, insertion of a PMMA intramedullary nail loaded with gentamicin and vancomycin; Group 3, no therapy, and Group 4 no fixation device and systemic antibiotic therapy for 1 week with teicoplanin i.m. (20mg/kg b.w. twice daily). At 7 weeks after inoculum, the right femurs were explanted sterilely for radiological (radiological score), microbiological, and histological tests. The radiological score showed that, between the 4 and the 7 weeks, the treatment of Group 2 (p < 0.01) and Group 4 determined an improvement in the injuries produced by the osteomyelitis. The lowest and best radiological score was observed in Group 2 that was significantly different from the other groups. The highest bacterial load in the femoral canal at sacrifice was found in Group 1 which was significantly different from Group 2 and Group 4 (p < 0.05). Finally, concerning the histological score, Group 2 produced a marked improvement (p < 0.005) of the bone injuries induced by the osteomyelitis in comparison with the other groups. The current findings showed that the gentamicin-vancomycin impregnated PMMA nail might effectively lead to MRSA infection healing after surgical debridement and immediate implantation.
Rationale of Nail Antibiotic Clothing and "in vivo" animal study / Giardino R.; Fini M.; Giavaresi G.; Sambri V.; Romanò C.; Meani E.; Soffiatti R.. - STAMPA. - (2007), pp. 359-366.
Rationale of Nail Antibiotic Clothing and "in vivo" animal study
GIARDINO, ROBERTO;SAMBRI, VITTORIO;
2007
Abstract
The study aimed to evaluate a new gentamicin-vancomycin-impregnated (2:1) PMMA coating of an internal fixation device, miniaturized to be tested in a rabbit model of osteomyelitis, to treat bone and intramedullary infections. The device was implanted in rabbit femur, previously infected, and bacteriological, radiological and histologic investigations were performed at 7 weeks after bacterial inoculum. Osteomyelitis of the right femur was induced in general anaesthesia in 20 New Zealand male rabbits with 0.2 ml (total load 106 CFU) of methicillin-resistant Staphylococcus aureus (MRSA) in the femoral canal. Four weeks after inoculum, after debridement of the right femur canal, the animals were divided into 4 groups of 5 animals each and treated according to the following protocols: Group 1, insertion of a steel AISI316 intramedullary nail; Group 2, insertion of a PMMA intramedullary nail loaded with gentamicin and vancomycin; Group 3, no therapy, and Group 4 no fixation device and systemic antibiotic therapy for 1 week with teicoplanin i.m. (20mg/kg b.w. twice daily). At 7 weeks after inoculum, the right femurs were explanted sterilely for radiological (radiological score), microbiological, and histological tests. The radiological score showed that, between the 4 and the 7 weeks, the treatment of Group 2 (p < 0.01) and Group 4 determined an improvement in the injuries produced by the osteomyelitis. The lowest and best radiological score was observed in Group 2 that was significantly different from the other groups. The highest bacterial load in the femoral canal at sacrifice was found in Group 1 which was significantly different from Group 2 and Group 4 (p < 0.05). Finally, concerning the histological score, Group 2 produced a marked improvement (p < 0.005) of the bone injuries induced by the osteomyelitis in comparison with the other groups. The current findings showed that the gentamicin-vancomycin impregnated PMMA nail might effectively lead to MRSA infection healing after surgical debridement and immediate implantation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
