Revista de la Asociación Argentina de Ortopedia y Traumatología
versión On-line ISSN 1852-7434
DIAZ GALLARDO, Paula et al. Methicillin-sensitive versus methicillin-resistant staphylococcus aureus in acute septic arthritis: experimental, epidemiological and clinical study in children. Rev. Asoc. Argent. Ortop. Traumatol. [online]. 2011, vol.76, n.2, pp. 112-121. ISSN 1852-7434.
Background: The main objectives of this paper were: to establish the epidemiology of septic arthritis in our community, determine the differences between methicillin-resistant and methicillin-sensitive Staphylococcus aureus septic arthritis, and determine the bactericidal properties of synovial fluid. Methods: Twenty-eight rabbits were used, divided into four groups of seven rabbits each; in groups I and II 0.3cc of methicillin-sensitive Staphylococcus aureus were inoculated, and in groups III and IV 0.3cc of methicillin-resistant Staphylococcus aureus were inoculated in the knee. We evaluated 16 children with septic arthritis, average age six years. Samples of synovial fluid were taken from 10 knees, placed in culture material and inoculated with methicillin-sensitive and methicillin-resistant staphylococcus. Results: The MRI showed signs of arthritis in all cases. Blood cultures were negative. The histological evaluation showed swelling, inflammation, granulation tissue, pus, and destroyed areas in the synovial membrane. In the 10 children evaluated the most affected joint was the knee; the causative agent could not be identified in nine cases. The study to assess the bactericidal activity of the synovial fluid revealed 75% of growth inhibition for methicillin-sensitive Staphylococcus aureus and no growth inhibition for the methicillin-resistant staphylococcus. Conclusions: The antibiotics used for the initial treatment in septic arthritis should vary according to the epidemiology of each region. Synovial fluid has important bactericidal properties against methicillin-sensitive Staphylococcus aureus, but not against methicillin-resistant staphylococcus. The MRI should be the imaging study of choice to diagnose and evaluate septic arthritis.
Palabras clave : Septic arthritis; Synovial fluid; Children.