Microbiological Profile and Resistance Patterns in Periprosthetic Joint Infections: A Regional Multicenter Study in Spain

Due to the significant number of microbiologically negative periprosthetic joint infections (PJIs), understanding the trend in etiology and resistance patterns is essential for the correct management of these infections. Currently, few studies have been published in Spain. In this study, we analyzed the incidence, clinical characteristics, etiology, and antibiotic resistance in patients with PJIs over the last 5 years in Navarra. In this multicentric and retrospective study, all patients diagnosed with PJIs in Navarra from 2019 to 2023 were included. Of the total 156 PJIs, 23% had negative cultures and 56% of these patients had been treated with antibiotics prior to sampling. Staphylococcus epidermidis with methicillin resistance was the predominant etiological agent, followed by Staphylococcus aureus and Cutibacterium acnes. Forty percent of the Gram-positive cocci (GPC) and 35% of the Gram-negative bacilli (GNB) were multidrug-resistant organisms (MDROs). Quinolone resistance was 46% for staphylococci and 18% for Gram-negatives. In addition, 9% of staphylococci were resistant to rifampicin. Antibiotic therapy administration prior to sampling is one of the main problems for microbiological diagnosis and is present more frequently in culture-negative PJIs (56%). New sequencing techniques could improve this difficulty. The high percentage of resistance in the microorganisms causing PJI leads us to reconsider the empirical treatment for suspected PJI, with the use of different therapeutic approaches depending on the time of infection and the possible use of new non-antibiotic therapies.