Gram-negative Prosthetic Joint Infections – A Retrospective Study

Abstract

The increasing challenges posed by gram-negative periprosthetic joint infections (PJIs) and advancing antibiotic resistance necessitate a comprehensive understanding of this devastation complication of joint arthroplasties. This retrospective cohort study, conducted at the Hospital of Traumatology and Orthopedics in Riga, Latvia, between 2018 and 2022, investigates the epidemiology, microbiological profiles, and treatment modalities of gram- negative PJIs. A retrospective cohort design was used, analyzing medical records of all gram-negative PJIs at the hospital during the specified period. The study included both mono- and polymicrobial infections. Ethics committee approvals from Rīga Stradinš University and the Hospital of Traumatology and Orthopedics were obtained. Data collection encompassed patient demographics, comorbidities, microbiological data, surgical interventions, and antimicrobial therapy. Statistical analysis was performed using Microsoft Excel and IBM SPSS Statistics. A total of 26 patients with 17 (65%) hip and 9 (35%) knee PJIs and a median age of 71 years were included. Cardiovascular diseases, including arterial hypertension and coronary heart disease were the most recorded comorbidities. There were 17 (64%) monomicrobial and 9 (35%) polymicrobial infections with a total of 37 isolated microorganisms. The most common isolated pathogens were of the Enterobacteriaceae family (57%), followed by non-fermenting gram-negative bacilli. The overall most isolated pathogens were Escherichia coli in 7 (19%) cases, followed by Proteus species in 6 (16%) cases, Klebsiella species in 5 (14%) cases and Pseudomonas species in 4 (11%) cases. Alarmingly, a substantial percentage (42%) exhibited resistance to ciprofloxacin, surpassing prior studies. Among the Enterobacteriaceae 76% of isolates were either resistant to ciprofloxacin or 3rd generation cephalosporins. In addition, four infections were caused by ESBL producing Enterobacteriaceae. The rarely isolated Acinetobacter spp. was found to be 4-MRGN in two out of three cases. Most frequently used antibiotic agents in our study were ciprofloxacin and beta-lactams. Overall, the intravenously used antibiotics were chosen according to the susceptibility testing. Interestingly in a few of our cases a purely oral fluoroquinolone therapy was used, which has not been suggested in any of the previous studies. We recorded exitus letalis in five (19%) cases, with three (12%) deaths attributed to PJI as these occurred within 30 days of diagnosis. In conclusion, our retrospective cohort study on gram-negative periprosthetic joint infections confirmed the high prevalence of resistances to the first line antibiotic treatments. In the future, it will be necessary to evaluate new strategies for the treatment of implant-related infections due to GNB due to the high incidence of resistances against fluoroquinolones and cephalosporins.