Boosting prevention efforts could reduce S. aureus prosthetic joint infections

Postoperative invasive Staphylococcus aureus infections were rare in a study of patients who underwent insertion of knee or hip prostheses, but hard-to-treat MRSA infections were relatively common, according to research published in Antimicrobial Resistance and Infection Control.

By optimizing prevention efforts, the medical community could diminish the burden associated with S. aureus prosthetic joint infections, according to the researchers.

“The health care and economic burden associated with infections are substantial,” the researchers wrote. “Health care resource use and cost of care are significantly increased due to longer hospital stays, rehospitalizations, lengthy antibiotic treatment, further surgery … rehabilitation, outpatient and emergency visits.”

Keith S. Kaye, MD, MPH, member of the Infectious Disease News Editorial Board and a professor of medicine at Wayne State University, and colleagues conducted a nested retrospective cohort analysis of adults who received a hip or knee prostheses at 11 hospitals from 2003 to 2006. All 13,719 prosthetic insertion procedures (62% knee and 38% hip) were performed within clean or clean-contaminated wound classification.

The investigators prospectively identified invasive S. aureus infections, nonsuperficial incisional surgical site infections (SSIs) and blood stream infections (BSIs) after each procedure. They estimated prevalence rates for every 100 procedures.
The researchers identified 92 invasive S. aureus infections. SSIs were more common (80%) than SSIs and BSIs combined (10%) or BSIs alone (10%).

The rates of invasive S. aureus infection were 0.57 (95% CI; 0.43-0.73) per 100 knee procedures and 0.83 (95% CI; 0.61-1.08) per 100 hip procedures; 53% of S. aureus infections were classified as MRSA. The median time-to-onset of infection was 34 days for knee insertion and 26 days for hip insertion. Infection was associated with higher risk index in the National Healthcare Safety Network (P ≤ .0001).

“Given the poor outcomes and high costs associated with these infections, this patient population represents a good target for interventions to mitigate risk for invasive postoperative S. aureus infections,” the researchers wrote. – by Allegra Tiver

Disclosures: The research was supported by Merck Sharp & Dohme. Kaye reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.