Native joint infections in Iceland 2003-2017: an increase in postarthroscopic infections

Gene expression of S100a8/a9 predicts Staphylococcus aureus-induced septic arthritis in mice

Septic arthritis is the most aggressive joint disease associated with high morbidity and mortality. The interplay of the host immune system with the invading pathogens impacts the pathophysiology of septic arthritis. Early antibiotic treatment is crucial for a better prognosis to save the patients from severe bone damage and later joint dysfunction. To date, there are no specific predictive biomarkers for septic arthritis. Transcriptome sequencing analysis identified S100a8/a9 genes to be highly expressed in septic arthritis compared to non-septic arthritis at the early course of infection in an Staphylococcus aureus septic arthritis mouse model. Importantly, downregulation of S100a8/a9 mRNA expression at the early course of infection was noticed in mice infected with the S. aureus Sortase A/B mutant strain totally lacking arthritogenic capacity compared with the mice infected with parental S. aureus arthritogenic strain. The mice infected intra-articularly with the S. aureus arthritogenic strain significantly increased S100a8/a9 protein expression levels in joints over time. Intriguingly, the synthetic bacterial lipopeptide Pam2CSK4 was more potent than Pam3CSK4 in inducing S100a8/a9 release upon intra-articular injection of these lipopeptides into the mouse knee joints. Such an effect was dependent on the presence of monocytes/macrophages. In conclusion, S100a8/a9 gene expression may serve as a potential biomarker to predict septic arthritis, enabling the development of more effective treatment strategies.

Early postoperative laboratory parameters are predictive of initial treatment failure in acute septic arthritis of the knee and shoulder joint

Septic arthritis is an orthopedic emergency potentially causing irreversible joint damage. However, the predictive value of potential risk factors such as early postoperative laboratory parameters remains uncertain. We investigated risk factors for initial surgical treatment failure using data from 249 patients (194 knees, 55 shoulders) treated for acute septic arthritis between 2003 and 2018. Necessity for further surgical intervention was defined as primary outcome. Demographic data, medical history, initial and postoperative laboratory parameters, Charlson Comorbidity Index (CCI), and Kellgren and Lawrence classification were collected. Two scoring systems were developed as tools for failure risk estimation after initial surgical irrigation and debridement. More than one intervention was necessary in 26.1% of cases. Treatment failure occurred significantly more often for those with longer symptom duration (p = 0.003), higher CCI grades (p = 0.027), Kellgren-Lawrence grade IV (p = 0.013), shoulder arthroscopy (p = 0.010), positive bacterial culture results (p < 0.001), slow postoperative CRP decline until day three (p = 0.032) and five (p = 0.015), reduced WBC-decline (p = 0.008), and lower hemoglobin (p < 0.001). Scores for third and fifth postoperative day achieved AUCs of 0.80 and 0.85, respectively. This study identified risk factors for treatment failure in patients with septic arthritis, suggesting that early postoperative laboratory parameters can guide further treatment.

SPILF update on bacterial arthritis in adults and children

In 2020 the French Society of Rhumatology (SFR) published an update of the 1990 recommendations for management of bacterial arthritis in adults. While we (French ID Society, SPILF) totally endorse this update, we wished to provide further information about specific antibiotic treatments. The present update focuses on antibiotics with good distribution in bone and joint. It is important to monitor their dosage, which should be maximized according to PK/PD parameters. Dosages proposed in this update are high, with the optimized mode of administration for intravenous betalactams (continuous or intermittent infusion). We give tools for the best dosage adaptation to conditions such as obesity or renal insufficiency. In case of enterobacter infection, with an antibiogram result "susceptible for high dosage", we recommend the requesting of specialized advice from an ID physician. More often than not, it is possible to prescribe antibiotics via the oral route as soon as blood cultures are sterile and clinical have symptoms shown improvement. Duration of antibiotic treatment is 6 weeks for Staphylococcus aureus, and 4 weeks for the other bacteria (except for Neisseria: 7 days).

Management and outcome of native joint septic arthritis: a nationwide survey in French rheumatology departments, 2016-2017

OBJECTIVES

To describe current management and outcome of native joint septic arthritis (NJSA) in French rheumatology departments.

METHODS

For this retrospective, nationwide multicentric study, 127 French rheumatology departments were contacted to report up to 12 cases of NJSA that occurred between 1 January 2016 and 31 December 2017. Characteristics, diagnosis procedures, therapeutic management and outcome were recorded.

RESULTS

Overall, 362 patients were included (mean age 64.0±18.6 years, median Charlson comorbidity index 3.5 (0-14)). Knee was the most frequent site (n=160 (38.9%)), and Staphylococcus sp (n=185 (51.4%)), the most frequent pathogen. All patients received antibiotics for a mean duration of 46.8 (±22.0) days, including intravenous route for a mean of 17.2 (±15.4) days. Management was heterogeneous. Surgical procedure was performed in 171 (48.3%), joint immobilisation in 128 (43.8%). During follow-up, 91 (28.3%) patients have had serious complications and 28 (9.2%) of them died. Factors associated with 1-year mortality were age (OR 1.08, 95% CI 1.04 to 1.13; p<0.001), Charlson's index (OR 1.30, 95% CI 1.06 to 1.58; p=0.012), presence of bacteraemia (OR 4.02, 95% CI 1.35 to 11.99; p=0.008), antibiotic use in the previous 3 months (OR 3.32, 95% CI 1.11 to 9.87; p=0.029) and Staphylococcus aureus NJSA compared with Streptococcus sp. NJSA (OR 7.24, 95% CI 1.26 to 41.68, p=0.027). The complete recovery with no adverse joint outcome at 1 year was observed in n=125/278 patients (55.0%).

CONCLUSION

Prognosis of NJSA remained severe with a high rate of morbimortality. Its management was very heterogeneous. This study highlights the importance of the new French recommendations, published after the completion of the study, in order to facilitate NJSA management.