Decoding resistance: a comprehensive study on pathogens and antibiotic efficacy in periprosthetic joint infections

Periprosthetic joint infection (PJI) continues to be a severe complication following total joint arthroplasty (TJA). Identifying the causative pathogens and their antibiotic resistance profiles is essential for the effective eradication.

In this retrospective study, 825 antibiograms and demographic data of patients with confirmed PJIs from 2005 to 2021 were evaluated. The resistance profile evaluation focused on the antibiotics ampicillin/sulbactam, clindamycin, gentamicin, vancomycin, ciprofloxacin and rifampicin.

Methicillin-sensitive staphylococcus aureus (MSSA) was the most prevalent pathogen (20.8%) followed by methicillin-resistant staphylococcus epidermidis (MRSE, 16.1%) and methicillin-sensitive staphylococcus epidermidis (MSSE, 10.8%). Polymicrobial (PM) PJI (15.9%) was also high with MSSA (21.2%) as the most frequent pathogen followed by gram-negative (GN) pathogens (20.2%) and MRSE (18.3%). The overall resistance rate against ampicillin/sulbactam and clindamycin was 42.3% and 40%, respectively. Vancomycin showed low resistance rates of nearly 1% with higher rates in enterococci (4%). MSSA and MRSA exhibit high sensitivity rates against gentamicin (97.4% and 89.5%). Gentamicin resistance was high in staphylococcus epidermidis (43%) and particularly in MRSE (64.6%). Ciprofloxacin resistance was especially high among MRSA (81.3%) and MRSE (84.0%) isolates, whereas sensitivity was most common in GN (78.5%) and MSSE (85.0%) groups. This study reveals high rates of MRSE, SE and GN pathogens causing PJI. GN and MRSE rates were also increased in PM PJI. The high overall resistance rates against ampicillin/sulbactam raise doubts as first line empiric oral antibiotic in PJI. The nearly 20% ciprofloxacin resistant GN pathogens should be alarming due to limited choice of biofilm-penetrating antibiotics in GN PJI.