Staphylococcus Aureus Musculoskeletal Infections: A Changing Spectrum Over the Past Decade

Saturday, October 26, 2013: 10:44 AM
Blue Spring (Hyatt Regency Orlando, formerly the Peabody)
Eric Sarkissian, BS, Itai Gans, BS, Melissa A. Gunderson, BA and John M. Flynn, MD, FAAP, Department of Orthopaedics, The Children's Hospital of Philadelphia, Philadelphia, PA

Purpose: The spectrum of pediatric musculoskeletal Staphylococcus aureus (SA) infections is changing. Other small series indicate a growing concern over the virulence and invasiveness of methicillin-resistant SA (MRSA) compared to methicillin-sensitive SA (MSSA) infections. The purpose of our study was to examine a decade of acute, community-acquired MRSA and MSSA musculoskeletal infections at our institution with respect to clinical course and complexity of care.

Methods: We studied a consecutive series of patients presenting to our institution with culture-positive Staphylococcus aureus osteomyelitis, septic arthritis, or both between January 2001 and June 2010. In an effort to minimize bias caused by nosocomial infections, post-operative and chronic infections were excluded. Data related to hospital course, laboratory values, and surgical interventions were collected and compared between MRSA and MSSA groups.

Results: In our study cohort, there were 148 cases of acute musculoskeletal SA infection (MSSA, n=111 and MRSA, n=37). From the start of the decade to its end, the proportion of musculoskeletal infections caused by MRSA increased (9% to 29%). Average duration of hospitalization was longer in the MRSA than MSSA group (13 days vs. 8 days, p=0.01). Multiple surgical procedures (n>1) were performed more frequently in MRSA than MSSA patients (38% vs. 15%, p=0.004). Mean presenting CRP level was higher in the MRSA than MSSA group (14.7 mg/L vs. 9.8 mg/L, p=0.02). Infection-related complications (deep venous thrombosis, septic emboli, septic shock, recurrent infection, and/or avascular necrosis) were more common in MRSA than MSSA patients (22% vs. 6%, p=0.008).

Conclusion: Over the past decade, pediatric MRSA musculoskeletal infections have increased in frequency and resulted in significantly longer inpatient stays, greater number of surgical interventions, higher presenting CRP level, and increased risk for developing complications compared to MSSA infections. The findings of this study are derived from the largest known series of children and adolescents presenting with culture-positive Staphylococcus aureus osteomyelitis, septic arthritis, or both. Prompt recognition and aggressive treatment of MRSA musculoskeletal infections are paramount for avoiding sequelae and improving patient outcomes.