gms | German Medical Science

Objectives: Periprosthetic joint infection (PJI) continues to be a severe complication following total joint replacement and presents a serious burden for the patient and the health system. Beside surgical debridement, the identification of causative pathogens and their antibiotic resistance profiles is essential for the effective eradication. PJI are often caused by a variety of bacteria, predominantly coagulase-negative staphylococci, and Staphylococcus aureus. The increasing occurrence of antibiotic-resistant strains (MRSA, ESBL, VRE) and polymicrobial infections complicate treatment strategies. Therefore, current trends in pathogen distribution and their resistances is an important element in selecting the appropriate antibiotic therapy. This study investigated the pathogen distribution and resistance development in PJI from 2005 to 2021.

Methods: In this retrospective study, 825 antibiograms and sociodemographic data (age, gender, surgical area, etc.) of patients with confirmed PJIs from 2005 to 2021 were evaluated (hip, knee, shoulder). The patients were primarily recruited from an academic level I arthroplasty center and other regional clinics. Mass spectrometry (MALDI-TOF MS) and microdilution methods (Vitek 2 XL) were used for pathogen identification and resistance profiling. The resistances were categorized into sensitive (S), intermediate (I), and resistant (R). The resistance profile evaluation focused on the antibiotic’s ampicillin/sulbactam, clindamycin, gentamicin, and vancomycin.

Results and conclusion: The data set provided a valid overview of pathogen distribution and sociodemographic characteristics in periprosthetic infections. Congruent with other studies, Staphylococcus epidermidis (30.2%) and Staphylococcus aureus (24.1%) were the most common causes of PJIs. Polymicrobial findings also accounted for a significant number of PJIs (15.9%). The risk of infection with gram-negative bacteria was significantly increased in the hip (Odds Ratio 2.194), whereas shoulder infections were primarily associated with Propionibacterium (Odds Ratio 9.613). Across all pathogen classes, resistance to ampicillin/sulbactam was found in 203 cases (42.3%), giving rise to the question, whether ampicillin/sulbactam is still suitable as an empirical antibiotic therapy until the pathogen is identified. High resistance (66.9%) to this substance was particularly noticeable in the Staphylococcus epidermidis group.Resistance to gentamicin was observed in 28.6% of the pathogens studied, hence an inconsiderate use of gentamicin in temporary spacers should be questioned critically. On the other side the sensitivity rate of the pathogens towards vancomycin was high (98.9%).

The analyzed and presented data provide a good overview of Germany’s current antibiotic resistance situation in PJIs. Taking the 825 analyzed cases in account, the documented resistances to common antibiotics in both empirical and specific therapy of PJI should critically accompany further discussions on suitable treatment concepts.