Microbial Resistance Patterns in Periprosthetic Joint Infection of the Knee: A 24-Year Longitudinal Study

Area of Science:

• Orthopedics
• Infectious Diseases
• Microbiology

Background:

• Effective management of knee periprosthetic joint infections (PJIs) requires early identification of causative microorganisms and appropriate empirical antibiotic therapy.
• This study aimed to analyze trends in PJI pathogens and antibiotic resistance over 24 years to inform empirical treatment strategies.

Purpose of the Study:

• To identify trends in causative microorganisms and antibiotic resistance profiles for knee periprosthetic joint infections (PJIs) over a 24-year period.
• To provide evidence-based recommendations for empirical antibiotic selection in managing knee PJIs.

Main Methods:

• Retrospective analysis of 487 first-episode knee periprosthetic joint infections (PJIs) between 2000 and 2023.
• Classification of PJIs using the Tsukayama criteria and multivariable logistic regression to identify risk factors for polymicrobial and resistant infections.

Main Results:

• Staphylococcus aureus was the most common pathogen; resistant cases remained consistent at 19-24% over 24 years.
• Prostheses in situ for less than one year significantly increased the risk of polymicrobial (11x) and resistant (3x) infections.
• Vancomycin with gram-negative coverage demonstrated >90% coverage across all PJI types, superior to flucloxacillin monotherapy.

Conclusions:

• Despite healthcare-associated resistance trends, primary knee PJI pathogens and resistance rates have remained stable over 24 years.
• Vancomycin plus gram-negative coverage is recommended for empirical treatment of early PJIs and septic PJIs.
• Beta-lactams remain effective for late hematogenous PJIs, while vancomycin is recommended for septic PJI regardless of timing.