Comparative severity of pediatric osteomyelitis attributable to methicillin-resistant versus methicillin-sensitive Staphylococcus aureus.

Background: Staphylococcus aureus remains the most common etiology of hematogenous osteomyelitis in children. Recently emerged virulent strains of methicillin-resistant S. aureus (MRSA) strains now predominate. It remains uncertain whether these pathogens cause a measurably more severe illness than methicillin-sensitive strains.

Methods: We reviewed records of 97 pediatric patients with hematogenous osteomyelitis of varying etiologies to determine whether there were significant differences among the groups in terms of predetermined measures of disease severity. These measures included degree and duration of elevated temperature, acute-phase reactants, length of hospitalization, the number of surgical procedures required, and long-term sequelae.

Results: Differences in the clinical course of illness were observed. Patients with MRSA had a significant increase in degree and duration of elevated temperature (P = 0.0001 for both), acute-phase reactant measures (white blood cell count, P = 0.0001; C-reactive protein, P = 0.0058; erythrocyte sedimentation rate, P = 0.0046), initial length of hospital stay (P = 0.0001), and surgical interventions (all procedures, P = 0.0001; therapeutic procedures, only P = 0.0002) as compared with patients with osteomyelitis caused by other bacterial pathogens and culture-negative osteomyelitis. A similar general pattern was observed when the analysis was restricted to culture-positive staphylococcal cases only.

Conclusions: Our results support the hypothesis that MRSA produces more severe bone infection and is likely to require more aggressive surgical and medical management.