Non-HACEK gram-negative bacilli endocarditis: a multicentre retrospective case-control study.

BACKGROUND: Infective endocarditis (IE) caused by non-HACEK gram-negative bacilli (GNB) is poorly characterised and may be emerging as a consequence of medical progress. METHODS: We performed an observational retrospective case-control study. Cases were non-HACEK GNB IE, definite or possible (modified Duke criteria), diagnosed in adults between 2007 and 2020 in six French referral hospitals. Two controls were included for each case (IE due to other bacteria, matched by sites and diagnosis date). RESULTS: Non-HACEK GNB were identified in 2.4% (77/3230) of all IE during the study period, with a mean age of 69.2 ± 14.6 years, and a large male predominance (53/77, 69%). Primary pathogens were Escherichia coli (n = 33), Klebsiella sp. (n = 12) and Serratia marcescens (n = 9), including eight (10%) multidrug-resistant GNB. Compared to controls (n = 154: 43% Streptococcus sp., 41% Staphylococcus sp. and 12% Enterococcus sp.), non-HACEK GNB IE were independently associated with intravenous drug use (IVDU, 8% vs. 2%, p = .003), active neoplasia (15% vs. 6%, p = .009), haemodialysis (9% vs. 3%, p = .007) and healthcare-associated IE (36% vs. 18%, p = .002). Urinary tract was the main source of infection (n = 25, 33%) and recent invasive procedures were reported in 29% of cases. Non-HACEK GNB IE were at lower risk of embolism (31% vs. 47%, p = .002). One-year mortality was high (n = 28, 36%). Comorbidities, particularly malignant hemopathy and cirrhosis, were associated with increased risk of death. CONCLUSIONS: Non-HACEK GNB are rarely responsible for IE, mostly as healthcare-associated IE in patients with complex comorbidities (end-stage renal disease, neoplasia), or in IVDUs.

How to Handle Concomitant Asymptomatic Prosthetic Joints During an Episode of Hematogenous Periprosthetic Joint Infection, a Multicenter Analysis.

BACKGROUND: Prosthetic joints are at risk of becoming infected during an episode of bacteremia, especially during Staphylocococcus aureus bacteremia. However, it is unclear how often asymptomatic periprosthetic joint infection (PJI) occurs, and whether additional diagnostics should be considered. METHODS: In this multicenter study, we retrospectively analyzed a cohort of patients with a late acute (hematogenous) PJI between 2005-2015 who had concomitant prosthetic joints in situ. Patients without at least 1 year of follow-up were excluded. RESULTS: We included 91 patients with a hematogenous PJI and 108 concomitant prosthetic joints. The incident PJI was most frequently caused by Staphylococcus aureus (43%), followed by streptococci (26%) and Gram-negative rods (18%). Of 108 concomitant prosthetic joints, 13 were symptomatic, of which 10 were subsequently diagnosed as a second PJI. Of the 95 asymptomatic prosthetic joints, 1 PJI developed during the follow-up period and was classified as a "missed" PJI at the time of bacteremia with S. aureus (1.1%). Infected prosthetic joints were younger than the noninfected ones in 67% of cases, and prosthetic knees were affected more often than prosthetic hips (78%). CONCLUSIONS: During an episode of hematogenous PJI, concomitant asymptomatic prosthetic joints have a very low risk of being infected, and additional diagnostic work-up for these joints is not necessary.

Lower Success Rate of Débridement and Implant Retention in Late Acute versus Early Acute Periprosthetic Joint Infection Caused by Staphylococcus spp. Results from a Matched Cohort Study.

BACKGROUND: Surgical débridement, antibiotics and implant retention (DAIR) is currently recommended by international guidelines for both early acute (postsurgical) and late acute (hematogenous) periprosthetic joint infections (PJIs). However, due to a different pathogenesis of infection, a different treatment strategy may be needed. QUESTIONS/PURPOSES: (1) Compared with early acute PJIs, are late acute PJIs associated with a higher risk of DAIR failure? (2) When stratified by microorganism, is the higher risk of failure in late acute PJI associated with Staphylocococcus aureus infection? (3) When analyzing patients with S. aureus infection, what factors are independently associated with DAIR failure? METHODS: In this multicenter observational study, early acute and late acute PJIs treated with DAIR were retrospectively evaluated and matched according to treating center, year of diagnosis, and infection-causing microorganism. If multiple matches were available, the early acute PJI diagnosed closest to the late acute PJI was selected. A total of 132 pairs were included. Treatment success was defined as a retained implant during follow-up without the need for antibiotic suppressive therapy. RESULTS: Late acute PJIs had a lower treatment success (46% [60 of 132]) compared with early acute PJIs (76% [100 of 132]), OR 3.9 [95% CI 2.3 to 6.6]; p < 0.001), but the lower treatment success of late acute PJIs was only observed when caused by Staphylococcus spp (S. aureus: 34% versus 75%; p < 0.001; coagulase-negative staphylococci: 46% versus 88%; p = 0.013, respectively). On multivariable analysis, late acute PJI was the only independent factor associated with an unsuccessful DAIR when caused by S. aureus (OR 4.52 [95% CI 1.79 to 11.41]; p < 0.001). CONCLUSIONS: Although DAIR seems to be a successful therapeutic strategy in the management of early acute PJI, its use in late acute PJI should be reconsidered when caused by Staphylococcus spp. Our results advocate the importance of isolating the causative microorganism before surgery. LEVEL OF EVIDENCE: Level III, therapeutic study.

Timing of implant-removal in late acute periprosthetic joint infection: A multicenter observational study.

OBJECTIVES: We evaluated the treatment outcome in late acute (LA) periprosthetic joint infections (PJI) treated with debridement and implant retention (DAIR) versus implant removal. METHODS: In a large multicenter study, LA PJIs of the hip and knee were retrospectively evaluated. Failure was defined as: PJI related death, prosthesis removal or the need for suppressive antibiotic therapy. LA PJI was defined as acute symptoms <3 weeks in patients more than 3 months after the index surgery and with a history of normal joint function. RESULTS: 445 patients were included, comprising 340 cases treated with DAIR and 105 cases treated with implant removal (19% one-stage revision (n = 20), 74.3% two-stage revision (n = 78) and 6.7% definitive implant removal (n = 7). Overall failure in patients treated with DAIR was 45.0% (153/340) compared to 24.8% (26/105) for implant removal (p < 0.001). Difference in failure rate remained after 1:1 propensity-score matching. A preoperative CRIME80-score ≥3 (OR 2.9), PJI caused by S. aureus (OR 1.8) and implant retention (OR 3.1) were independent predictors for failure in the multivariate analysis. CONCLUSION: DAIR is a viable surgical treatment for most patients with LA PJI, but implant removal should be considered in a subset of patients, especially in those with a CRIME80-score ≥3.

Is Gram staining still useful in prosthetic joint infections?

Introduction: Staphylococcus aureus is an independent risk factor for DAIR failure in patients with a late acute prosthetic joint infection (PJI). Therefore, identifying the causative microorganism in an acute setting may help to decide if revision surgery should be chosen as a first surgical approach in patients with additional risk factors for DAIR failure. The aim of our study was to determine the sensitivity of Gram staining in late acute S. aureus PJI. Material and methods: We retrospectively evaluated all consecutive patients between 2005-2015 who were diagnosed with late acute PJI due to S. aureus. Late acute PJI was defined as the development of acute symptoms and signs of PJI, at least three months after the index surgery. Symptoms existing for more than three weeks were excluded from the analysis. Gram staining was evaluated solely for synovial fluid. Results: A total of 52 cases were included in the analysis. Gram staining was positive with Gram positive cocci in clusters in 31 cases (59.6%). Patients with a C-reactive protein (CRP) > 150 mg/L at clinical presentation had a significantly higher rate of a positive Gram stain (30/39, 77%) compared to patients with a CRP ≤ 150 mg/L (4/10, 40%) (p=0.02). A positive Gram stain was not related to a higher failure rate (60.6% versus 57.9%, p 0.85). Conclusion: Gram staining may be a useful diagnostic tool in late acute PJI to identify S. aureus PJI. Whether a positive Gram stain should lead to revision surgery instead of DAIR should be determined per individual case.

Clinical outcome and risk factors for failure in late acute prosthetic joint infections treated with debridement and implant retention.

OBJECTIVES: Debridement, antibiotics and implant retention (DAIR) is the recommended treatment for all acute prosthetic joint infections (PJI), but its efficacy in patients with late acute (LA) PJI is not well described. METHODS: Patients diagnosed with LA PJI between 2005 and 2015 were retrospectively evaluated. LA PJI was defined as the development of acute symptoms (≤ 3 weeks) occurring ≥ 3 months after arthroplasty. Failure was defined as: (i) the need for implant removal, (ii) infection related death, (iii) the need for suppressive antibiotic therapy and/or (iv) relapse or reinfection during follow-up. RESULTS: 340 patients from 27 centers were included. The overall failure rate was 45.0% (153/340). Failure was dominated by Staphylococcus aureus PJI (54.7%, 76/139). Significant independent preoperative risk factors for failure according to the multivariate analysis were: fracture as indication for the prosthesis (odds ratio (OR) 5.4), rheumatoid arthritis (OR 5.1), age above 80 years (OR 2.6), male gender (OR 2.0) and C-reactive protein > 150 mg/L (OR 2.0). Exchanging the mobile components during DAIR was the strongest predictor for treatment success (OR 0.35). CONCLUSION: LA PJIs have a high failure rate. Treatment strategies should be individualized according to patients' age, comorbidity, clinical presentation and microorganism causing the infection.