Incidence and burden of Staphylococcus aureus infection after orthopedic surgeries

To assess the 180-day incidence of Staphylococcus aureus infections following orthopedic surgeries using microbiology cultures.

Retrospective observational epidemiology study.

National administrative hospital database.

Adult patients with an elective admission undergoing orthopedic surgeries in the inpatient and hospital-based outpatient settings discharged between July 1, 2010, and June 30, 2015.

Patients were identified from 181 hospitals reporting microbiology results to the Premier Healthcare Database. Orthopedic surgeries were defined using International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) procedure and current procedural terminology (CPT) codes. Microbiology cultures and ICD-9/10 diagnosis codes identified surgical site infections (SSIs), bloodstream infections (BSIs), and other infections associated postoperatively (eg, respiratory and urinary tract infections).

Among 359,268 inpatient orthopedic surgical encounters, the S. aureus infection incidence was 1.13%: SSI, 0.68%; BSI, 0.28%; and other types, 0.17%. Among 292,011 outpatient encounters, the S. aureus incidence was 0.78%: SSI, 0.55%; BSI, 0.12%; and other types, 0.11%. Methicillin-resistant S. aureus (MRSA) infections accounted for 46% and 44% in the respective settings. Plastic/hand-limb reattachment and amputation had the highest overall S. aureus incidence in both settings. S. aureus was the most commonly isolated microorganism among culture-confirmed SSIs (48.0%) and BSIs (35.0%), followed by other Enterobacteriaceae (14.0%) for SSIs and Escherichia spp (12.5%) for BSIs.

These findings suggest that S. aureus infections continue to be an important contributor to the burden of postoperative infections after inpatient and outpatient orthopedic procedures.