POLYMICROBIAL ETIOLOGY OF PROSTHETIC JOINT INFECTIONS (PJI) AS A RISK FACTOR OF TREATMENT FAILURE AFTER THE REVISION SURGERY

To evaluate the proportion of microbial associations causing PJI, diversity of their strains and impact on treatment failure after the removal of the hip implant and insertion of a spacer. Spectrum of pathogens in 189 cases of PJI was studied retrospectively. Strains were isolated from the joint aspirates, tissue samples and removed orthopedic devices. The cohort comprised 144 cases of PJI after primary THA and 45 cases after the hip replacement revision surgery. All patients underwent first stage of two-stage revision procedure which involves the removal of a hip implant, debridement of infected periprosthetic tissues and subsequent insertion of a bone cement spacer. There were 92 males and 97 females (median age of 57 yrs). Statistical analysis of the results was performed with GraphPad Prism 6.0 (California, USA). Microbial associations were detected in 28.6% (n=54) of PJI cases. Gram-positive bacteria prevailed in both groups with mono- and polymicrobial etiology. There were 52.5% of S. aureus isolates in monomicrobial group and 25% isolates in polymicrobial group (p=0.0002). This also included 8.4 and 20.6% isolates of MRSA, respectively (p Microbial associations were found in 28.6% of PJI cases after hip arthroplasty. They posed a significant risk for treatment failure after removal of the hip implant and insertion of a spacer. The multidrug-resistant strains (MRSA, Acinetobacter sp. and P. aeruginosa) were often isolated in microbial associations. Our results suggest that further study of the risk factors for polymicrobial infection is necessary in patients with PJI. Identification of a patient group at high risk for developing polymicrobial PJI will allow prescription of empiric antimicrobial therapy in time, taking into account possible multi-resistant pathogens.