Is There a Difference in Microbiological Epidemiology and Effective Empiric Antimicrobial Therapy Comparing Fracture-Related Infection and Periprosthetic Joint Infection? A Retrospective Comparative Study

Abstract

This study aims to investigate (1) microbial patterns in fracture-related infections (FRIs) in comparison to microbiological patterns of periprosthetic joint infections (PJIs), (2) the identification of effective empiric antibiotic therapy for FRIs and PJIs and (3) analysis of difficult-to-treat (DTT) pathogens. Patients treated for FRIs or PJIs from 2017 to 2020 were evaluated for pathogens detected during treatment. Antibiotic susceptibility profiles were examined with respect to broadly used antibiotics and antibiotic combinations. Resistance rates to rifampicin or fluoroquinolone were determined. A total of 81 patients with PJI and 86 with FRI were included in the study. For FRIs Staphylococcus aureus was the most common infection-causing pathogen (37.4% vs. 27.9% for PJI). Overall, there was no statistical difference in pathogen distribution (p = 0.254). For FRIs, combinations of gentamicin + vancomycin (93.2%), co-amoxiclav + glycopeptide and meropenem + vancomycin (91.9% each) would have been effective for empiric therapy, similar to PJIs. Difficult to treat pathogens were more frequently detectable in PJIs (11.6% vs. 2.3%). Empiric therapy combinations such as gentamicin + vancomycin, co-amoxiclav + glycopeptide or meropenem + vancomycin, are effective antibiotic strategies for both FRI and PJI patients. More DTT pathogens were detectable in PJIs compared to FRIs.

Validation of the diagnostic criteria of the consensus definition of fracture-related infection

“…Furthermore, negative cultures were found in 41 (8.5%) patients in the FRI group. The number of culture-negative infections in our cohort is comparable to the orthopedic device-related (i.e., PJI, FRI) literature, where the rate ranges between 6% and 15% [26][27][28][29][30] . Bacteria are not uniformly distributed in FRI tissue, so it is possible to harvest several specimens with very few or even no bacteria.…”

What Is the Most Effective Empirical Antibiotic Treatment for Early, Delayed, and Late Fracture-Related Infections?

“…Current recommendations of an initial empiric broad-spectrum therapy include a lipopeptide or glycopeptide and an agent covering Gram-negative bacilli [15]. However, these guidelines targeted antibiotic treatment strategies that are currently extrapolated from PJI and even though no differences in microbiological epidemiology between PJI and FRI were reported, studies focusing on antibiotic sensitivity of pathogens in FRI are required [14,18]. Consistent with these recommendations and other reports [15,19], the combination of a glycopeptide such as vancomycin with broad-spectrum antibiotics such as meropenem achieved the highest efficacy in antimicrobial treatment of early, delayed, and late FRI.…”

“…However, data on antimicrobial susceptibility testing and empiric antibiotic treatment strategies for FRI with respect to the onset of infection in clinical practice are still pending. In addition, treatment strategies are often extrapolated from periprosthetic joint infection (PJI) [17,18], although, in contrast to PJI, detailed analysis of pathogens and their antibiotic susceptibility/resistance is still scarce for FRI. Therefore, the purpose of this study was to answer the following question:…”

The Microbiological Etiology of Fracture-Related Infection

“…While stability is important for both the prevention and treatment of FRI, it is not clear whether it influences the type of local infecting agents ( Foster et al., 2021 ). Although data on the topic is limited, a recent study showed that there is no significant difference in pathogen distribution between FRI and PJI ( Rupp et al., 2021 ).…”