Microbiological Profiles of Patients with Spondylodiscitis.

Spondylodiscitis is a severe spinal infection that requires an effective antibiotic treatment. Therefore, we sought to analyse the causative pathogens from intraoperative specimen in patients with spondylodiscitis and a need for surgery. To this end, we performed a retrospective study of all patients with spondylodiscitis and a need for operative treatment admitted to our hospital between January 2020 and December 2022. A total of 114 cases with spondylodiscitis were identified. A total of 120 different pathogens were detected. Overall, 76.7% of those microorganisms were Gram-positive bacteria. The most common causative pathogen was Staphylococcus aureus (n = 32; 26.6%), followed by coagulase-negative staphylococci (n = 28; 23.4%), of which Staphylococcus epidermidis (n = 18; 15%) was the most frequently detected, as well as enterococci (n = 10; 8.4%) and Streptococcus spp. (n = 11; 9.2%). Moreover, 19.1% (n = 22) and 3.4% (n = 4) of all detected isolates were Gram-negative pathogens or fungi, respectively. Overall, 42.8% of all coagulase-negative staphylococci were oxacillin-resistant, while none of them were vancomycin-resistant. In summary, 50% of the pathogens could be identified as staphylococci. The results of our study highlight the important burden of oxacillin-resistant Gram-positive bacteria as an aetiological cause of spondylodiscitis, providing a relevant finding for antimicrobial stewardship programmes.

Microbiological Trends and Antibiotic Susceptibility Patterns in Patients with Periprosthetic Joint Infection of the Hip or Knee over 6 Years.

We sought to analyze trends of the causative pathogens and their antibiotic susceptibility patterns in patients with periprosthetic joint infections (PJI) of the hip and knee to get better insights and improve treatment. Retrospective evaluation of all consecutive patients with microbiological detection of a causative pathogen at a tertiary endoprothetic referral center between January 2016 and December 2021 in Germany was performed. Overall, 612 different microorganisms could be detected in 493 patients (hip: n = 293; knee: n = 200). Evaluation did not show a change in the relative abundance of pathogens detected, with coagulase-negative staphylococci (n = 275; 44.9%) found frequently, followed by S. aureus (n = 86; 14.1%), Enterococcus species (n = 57; 9.3%), Streptococcus species (n = 48; 7.8%), and Gram-negative bacteria (n = 80; 13.1%). Evaluation of the antibiotic susceptibilities showed increasing rates of oxacillin-resistant coagulase-negative staphylococci (60.4%; 46.8−76.7%) and piperacillin-tazobactam-resistant Gram-negative bacteria (26.5%; 0−57.1%), although statistically not significant. Resistance of Gram-positive bacteria to vancomycin (<1%) and Gram-negative microorganisms to meropenem (1.25%) remained an exception. In summary, coagulase-negative staphylococci, as the most frequent pathogen, displayed a continuously high rate of oxacillin resistance. For the highest antimicrobial coverage in the case of an empiric therapy/unknown pathogen, vancomycin might be chosen. Level of evidence: IV.

Microbiological Profiles of Patients with Periprosthetic Joint Infection of the Hip or Knee.

Periprosthetic joint infections (PJI) are one of the most devastating consequences after total joint arthroplasty. We sought to analyze the causative pathogens of patients with PJI to get better insights and improve treatment. We performed a retrospective study of all patients with PJI of the hip and knee with microbiological detection of a causative pathogen at a tertiary endoprothetic referral center between January 2016 and March 2021. A total of 432 cases with PJI (hip: n = 250; knee: n = 182) were included. The most common causative pathogen were coagulase-negative staphylococci (n = 240; 44.2%), of which Staphylococcus epidermidis (n = 144; 26.7%) was the most frequently detected, followed by S. aureus (n = 77; 14.3%) and enterococci (n = 49; 9%). Gram-negative pathogens and fungi could be detected in 21% (n = 136) and 2.4% (n = 13) of all cases. Overall, 60% of all coagulase-negative staphylococci were oxacillin-resistant, while none of these displayed to be vancomycin-resistant. In summary, the majority of pathogens in cases of PJI could be identified as coagulase-negative staphylococci. For empirical therapy vancomycin might provide the highest antimicrobial coverage in case of an unknown pathogen.

Synovial Complement Factors in Patients with Periprosthetic Joint Infection after Undergoing Revision Arthroplasty of the Hip or Knee Joint.

The role and diagnostic value of the synovial complement system in patients with low-grade periprosthetic joint infection (PJI) are unclear. We sought to evaluate, for the first time, the usefulness of synovial complement factors in these patients by measuring the individual synovial fluid levels of complement factors (C1q, C3b/iC3b, C4b, C5, C5a, C9, factor B, factor D, factor H, factor I, properdin, and mannose-binding lectin [MBL]). The patients (n = 74) were classified into septic (n = 28) and aseptic (n = 46). Receiver-operator characteristic curves and a multiple regression model to determine the feasibility of a combination of the tested cytokines to determine the infection status were calculated. The synovial fluid levels of C1q, C3b/C3i, C4b, C5, C5a, MBL, and properdin were significantly elevated in the PJI group. The best sensitivity and specificity was found for C1q. The multiple regression models revealed that the combination of C1q, C3b/C3i, C4b, C5, C5a, and MBL was associated with the best sensitivity (83.3%) and specificity (79.2%) for a cutoff value of 0.62 (likelihood ratio: 4.0; area under the curve: 0.853). Nevertheless, only a combined model showed acceptable results. The expression patterns of the complement factors suggested that PJI activates all three pathways of the complement system.

The Influence of Iodine-Impregnated Incision Drapes on the Bacterial Contamination of Scalpel Blades in Joint Arthroplasty.

BACKGROUND: Prosthetic joint infections (PJI) are a disastrous and feared complication in arthroplasty. Over the past decades, surgeons have tried to lower infection rates through all sorts of improvements. At present, it is impossible to reduce the risk to zero. As the contamination of surgical instruments and the surgical field has been identified as a remaining gap prone for infection, scalpel blades among others have become a focal point of several studies. This study is the first to compare the effect of adhesive incision drapes on contamination rates of scalpel blades in primary arthroplasty of the hip and knee. METHODS: A total of 344 microbiologic blade culture results from 2 study groups with and without drape usage and 1 group with known PJI were analyzed and compared to histopathologic and microbiologic tissue results. RESULTS: In 78% of all positive cultures, the bacteria were part of the local skin flora. The contamination rate for the skin blades with a drape was 3.81% vs 12.19% without drape usage. A significant difference was determined between positive skin blade culture results incision drape usage (P = .031). The different pathogens likely responsible for the PJI correlated with the deep blade cultures (P ≤ .01). The overall contamination rate of surgical blades (1.37%) is comparatively low to the results obtained from other surgical equipment in literature. None of those blade-positive patients developed a surgical site infection during 12-month follow-up. CONCLUSION: Iodine-impregnated incision drapes are able to reduce surgical skin blade contamination. Further studies may be needed to assess the relationship between blade contamination and surgical site infections.

The use of negative pressure wound therapy increases failure rate in debridement and implant retention for acute prosthetic joint infection.

BACKGROUND: To date only scanty data exist regarding the effect of failed debridement, antibiotics, irrigation and retention of the prostheses (DAIR) and negative pressure wound therapy (NPWT) on the outcome of a subsequent exchange arthroplasty. OBJECTIVE: The objective of this study was to determine the success rate of a two- or multi-stage procedure after initial failed DAIR/NPWT in patients with an acute periprosthetic joint infection (PJI) and to evaluate the influence of possible risk factors for treatment failure. METHODS: Nineteen consecutive patients with a persisting PJI and ongoing NPWT after treatment of an acute PJI with DAIR of the hip or knee joint from October 2010 to June 2017 were included. All patients were treated according to a structured treatment algorithm after referral to our hospital. The endpoint was a successful reimplantation with absence of signs of infection two years after replantation ("replantation group") or treatment failure ("treatment failure group") in terms of a permanent girdlestone arthroplasty, fistula, amputation or death. A risk factor analysis was performed between the two groups. RESULTS: Explantation was performed in 15 cases, amputation in one case, and DAIR/establishment of a fistula in three cases. The treatment success rate after reimplantation in terms of "definitively free of infection" two years after surgery according to Laffer was 36.85% (seven out of 19 patients). Statistical analysis revealed the number of surgeries until wound consolidation (p= 0.007), number of detected bacterial strains (p= 0.041), a polymicrobial PJI (p= 0.041) and detection of a difficult-to-treat organism (p= 0.005) as factors associated with treatment failure. After failed DAIR/NPWT we could detect a significant higher number of different bacterial strains (p= 0.001). CONCLUSIONS: The treatment success rate after failed DAIR and NPWT with 36% is low and associated with a high treatment failure rate (permanent girdlestone arthroplasty, fistula or amputation, death). Thus, the definition of risk factors is crucial. We found that the number of revisions until wound consolidation, a polymicrobial PJI and detection of a difficult-to-treat organisms were risk factors for treatment failure. Furthermore, after failed DAIR/NPWT we could detect a significant higher number of different bacterial strains, with a possible adverse effect on a consecutive exchange.