Cerebral empyema and abscesses due to Cutibacterium acnes

INTRODUCTION

Cutibacterium acnes is a commensal bacterium of the skin, frequently reported in prosthetic shoulder or spinal implant infections, but rarely in cranial and intracranial infections.

METHODS

We retrospectively reviewed patients with intracranial samples positive to Cutibacterium acnes managed in the neurosurgical units of our hospital of Lyon, France, between 2008-2016.

RESULTS

We included 29 patients, of whom 23 had empyema (with or without abscess), 17 had cranial osteomyelitis, and six only had abscess. Prior neurosurgery was reported in 28 patients, and the remaining patient had four spontaneous abscesses. Twelve patients had polymicrobial infections, including methicillin-susceptible Staphylococcus in 11 cases. The clinical diagnosis was difficult because of indolent and delayed symptoms: a CT scan or MRI was required. Thirteen patients (52%) had material at the infection site. All patients with bone flap implant or bones from biological banks had a bone flap-associated infection. Drainage was surgically performed in 25 cases or by CT scan-guided aspiration in four cases. All patients received an adapted antibiotic therapy (from three weeks to six months). The outcome was favorable in 28 patients. Three patients relapsed during the antibiotic therapy, requiring further surgery.

CONCLUSION

Cutibacterium acnes can be responsible for postoperative empyema and cerebral abscesses, with particular indolent forms, which make their diagnosis difficult. They are often polymicrobial and associated with bone flap osteomyelitis. Their outcome is favorable after drainage and adapted antibiotic therapy.

400. Comparison of Tolerance and Microbiological Efficacy of Cefepime and Piperacillin/Tazobactam in Combination with Vancomycin as Empirical Antimicrobial Therapy of Prosthetic Joint Infection: A Propensity-Matched Cohort Study

Background

The use of piperacillin/tazobactam with vancomycin as empirical antimicrobial therapy (EAT) for prosthetic joint infection (PJI) has been associated with an increased risk of acute kidney injury (AKI), leading to propose cefepime as an alternative since 2017 in our reference center. The present study compared microbiological efficacy and tolerance of these two EAT strategies.

Methods

All adult patients with PJI empirically treated by vancomycin-cefepime (n = 89) were enrolled in a prospective observational study, and matched with vancomycin-piperacillin/tazobactam-treated historical controls (n = 89) according to a propensity score including age, baseline renal function and concomitant use of other nephrotoxics. The two groups were compared using Kaplan–Meier curve analysis and non-parametric tests (Fisher exact test and Mann–Whitney U-test) regarding: (i) the proportion efficacious empirical regimen (i.e., at least one of the two molecules active against the identified organism(s) based on in vitro susceptibility testing); and (ii) the incidence of empirical therapy-related adverse events (AE), classified according to the Common terminology criteria for AE (CTCAE).

Results

Among the 146 (82.0%) documented infections, the EAT was considered as efficacious in 77 (98.7%) and 65 (98.5%) of the piperacillin–tazobactam and cefepim-treated patients, respectively (P = 1.000). The rate of AE, and in particular AKI, was significantly higher in the vancomycin–piperacillin/tazobactam (n = 27 [30.3%] and 23 [25.8%%]) compared with the vancomycin-cefepim (n = 13 [14.6%] and 6 [6.7%]) group (P = 0.019 and <0.001, respectively; figure), leading to a premature EAT discontinuation in 20 (22.5%) and 5 (5.6%) patients (P = 0.002). Of note, no significant differences were observed between the two groups regarding sex (91 males; 51.1%), median age (68-year-old; IQR, 59.3–75), main comorbidities including baseline renal function and proportion of patients receiving other nephrotoxics, and vancomycin plasmatic overload.

Conclusion

The empirical use of vancomycin-cefepim in PJI was as efficient as vancomycin–piperacillin/tazobactam, and was associated with a significantly lower incidence of AKI.

Disclosures

All authors: No reported disclosures.

2579. Impact on the Gut Microbiota of the Prolonged Antimicrobial Therapy in Patients with Bone and Joint Infection (BJI): Results From the OSIRIS Prospective Study in France

Background

There is growing interest about the deleterious impact of antibiotics on loss of gut symbiosis, called dysbiosis. As patients with BJI require antibiotics usually during 6 to 12 weeks, it is of interest to determine whether dysbiosis is frequent in this population, and if it could potentially reversible or not.

Methods

Multicentric prospective cohort study in France (EudraCT 2016-003247-10) including patients with 3 categories of BJI: native, osteosynthesis-related and prosthetic joint infection (PJI). At the time of suspicion (V1), at the end of therapy (V2) and then 2 weeks after stopping therapy (V3), blood and fecal samples were collected. Extracted DNA from stool was sequenced using shotgun metagenomic sequencing based on illumina library and Iseq instrumentation. Data run through a dedicated pipeline in order to produce microbiome indexes such as Sympson or Shannon diversities indexes. Gut microbiome and inflammation markers were analyzed including fecal neopterin, a maker of gut inflammation.

Results

Concerning the 62 patients included (mean age, 60 years; mean duration of antibiotics, 66 days), 27 had native, 14 had osteosynthesis and 21 had PJI. The most frequently prescribed drug was a fluoroquinolone, followed by a third-generation cephalosporin and vancomycin. Stools from 42 of them were analyzed as per protocol. Overall, the mean Shannon richness index decreased from 0.904 at V1 to 0.845 at V2; the Bray-Curtis index underlined the difference in microbiome reconstitution at V3 in comparison with V1. We report significant microbiome loss of diversity at V2, that was reversible at V3 in patients with native BJI and osteosynthesis-related BJI, but not in patients with PJI (figure). Fecal neopterin increased between V1 and V2 (mean 221.6 and 698.1 pmol/g of feces, respectively) and then decreased at V3 (422.5 pmol/g), and could be a potential surrogate marker of gut dysbiosis. Of note, patients with abnormal CRP at the end of antibiotics had high neopterin values, that raises the hypothesis that abnormal CRP at the end of antibiotics could be in relation with gut dysbiosis rather than uncured BJI.

Conclusion

The impact of antibiotics on the gut microbiota of patients with BJI seems to be significant, especially in patients with PJI who could be candidate for fecal microbiota transplantation.

Disclosures

All authors: No reported disclosures.

384. Denosumab-Related Osteonecrosis of the Jaw: an Emergent and Potentially Complex Bone and Joint Infection

Background

Osteonecrosis of the jaw is a known complication of antiresorptive treatment, like bisphosphonate. More recently, denosumab was validated as a treatment in the osteoporosis and bone metastasis. Its mechanism is different from bisphosphonate but induces also a decrease of bone resorption and a risk of osteonecrosis of the jaw. In case of treatment failure by a dental surgeon or in complex cases, patients could be addressed to a bone and joint infection (BJI) reference center. The aim of this study was to analyze microbiology, as well as surgical and medical care of patients who present denosumab-related osteonecrosis of the jaw (DRONJ) and who were treated in a bone and join reference center.

Methods

All patients managed in our BJI reference center between January 2013 and December 2018 for a DRONJ were included in our retrospective observational monocentric cohort.

Results

Twelve patients (median age 71; ratio M/W 0.7) with a DRONJ (metastatic cancer, n = 10 (83%)) in grade 3 (n = 5), 2 (n = 4), 1 (n = 3) were included. Only 3 patients (25%) had a dental health control before initiating the treatment by denosumab and 7 patients (58%) had a dental surgical procedure done before the DRONJ. Eleven patients had a bone exposure, treated at least with a scaling and mucosal closure at the same time. All infections with bacterial cultures (n = 11 (91%)) were polymicrobial, including 8 (72%) with Streptococcus spp; 8 (72%) with anaerobia including 2 (18%) with Actinomyces; 5 (45%) with Staphylococcus spp; 5 (45%) with enterobacteria; 3 (27%) with Candida spp; 2 (17%) with a non-fermentative Gram-negative bacilli and 7 (64%) with others bacteria. All patients (n = 12) received a betalactam, 8 (66%) a lincosamide or a synergistin, 5 (41%) an antifungal, 5 (41%) metronidazole, 4 (33%) a fluoroquinolone, 3 (25%) a glycopeptide and 2 (17%) other antibiotics. The median follow-up was 6 months. Eight patients were cured after a medico-surgical care and a median duration of antibiotics of 97 days (including 28.5 days in intravenous). 2 patients required a suppressive antibiotic treatment, 1 relapsed at a distance of the treatment and 1 died from some other causes.

Conclusion

DRONJ is a potential complex BJI, for which some patients could benefit from medical care in a BJI reference center.

Disclosures

All authors: No reported disclosures.

Interaction Between Staphylococcal Biofilm and Bone: How Does the Presence of Biofilm Promote Prosthesis Loosening?

With the aging of population, the number of indications for total joint replacement is continuously increasing. However, prosthesis loosening can happen and is related to two major mechanisms: (1) aseptic loosening due to prosthesis micromotion and/or corrosion and release of wear particles from the different components of the implanted material and (2) septic loosening due to chronic prosthetic joint infection (PJI). The “aseptic” character of prosthesis loosening has been challenged over the years, especially considering that bacteria can persist in biofilms and be overlooked during diagnosis. Histological studies on periprosthetic tissue samples reported that macrophages are the principle cells associated with aseptic loosening due to wear debris. They produce cytokines and favor an inflammatory environment that induces formation and activation of osteoclasts, leading to bone resorption and periprosthetic osteolysis. In PJIs, the presence of infiltrates of polymorphonuclear neutrophils is a major criterion for histological diagnosis. Neutrophils are colocalized with osteoclasts and zones of osteolysis. A similar inflammatory environment also develops, leading to bone resorption through osteoclasts. Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus lugdunensis are the main staphylococci observed in PJIs. They share the common feature to form biofilm. For S. aureus and S. epidermidis, the interaction between biofilm and immunes cells (macrophages and polymorphonuclear neutrophils) differs regarding the species. Indeed, the composition of extracellular matrix of biofilm seems to impact the interaction with immune cells. Recent papers also reported the major role of myeloid-derived suppressor cells in biofilm-associated PJIs with S. aureus. These cells prevent lymphocyte infiltration and facilitate biofilm persistence. Moreover, the role of T lymphocytes is still unclear and potentially underestimates. In this review, after introducing the cellular mechanism of aseptic and septic loosening, we will focus on the interrelationships between staphylococcal biofilm, immune cells, and bone cells.

Population pharmacokinetics and probability of target attainment of ertapenem administered by subcutaneous or intravenous route in patients with bone and joint infection

Background

Ertapenem is a therapeutic option in patients with Gram-negative bone and joint infection (BJI). The subcutaneous (sc) route of administration is convenient in the outpatient setting and has shown favourable pharmacokinetics (PK), but available data on ertapenem are limited.

Objectives

To perform population PK analysis and pharmacokinetic/pharmacodynamic (PK/PD) simulation of ertapenem administered by the intravenous (iv) or sc route to patients with BJI.

Patients and methods

This was a retrospective analysis of PK data collected in patients with BJI who received iv or sc ertapenem. Measured ertapenem concentrations were analysed with a non-parametric population approach. Then, simulations were performed based on the final model to investigate the influence of ertapenem route of administration, dosage and renal function on the probability of achieving a pharmacodynamic (PD) target, defined as the percentage of time for which free plasma concentrations of ertapenem remained above the MIC (fT>MIC) of 40%.

Results

Forty-six PK profiles (13 with iv and 33 with sc ertapenem) with a total of 133 concentrations from 31 subjects were available for the analysis. A two-compartment model with linear sc absorption and linear elimination best fitted the data. Creatinine clearance was found to significantly influence ertapenem plasma clearance. Simulations showed that twice daily dosing, sc administration and renal impairment were associated with an increase in fT>MIC and target attainment.

Conclusions

Our results indicate that 1 g of ertapenem administered twice daily, by the iv or sc route, may optimize ertapenem exposure and achievement of PK/PD targets in patients with BJI.

The CRIOAc healthcare network in France: A nationwide Health Ministry program to improve the management of bone and joint infection

BACKGROUND

Bone and joint infections (BJIs) have a major clinical and economic impact in industrialized countries. Its management requires a multidisciplinary approach, and a great experience for the most complicated cases to limit treatment failure, motor disability and amputation risk. To our best knowledge there is not currently national specific organization dedicated to manage BJI. Is it possible to build at a national level, a network involving orthopaedic surgeons, infectiologists and microbiologists performing locally multidisciplinary meetings to facilitate the recruitment and the management of patients with complex bone and joint infection in regional centers?

HYPOTHESIS

A national healthcare network with regional labeled centers creates a dynamic that improves the recruitment, the management, the education, and the clinical research in the field of complex BJI.

PATIENTS AND METHODS

We describe the history of this unique national healthcare network and how it works, specify the missions confided to the CRIOAcs, evaluate the activity of the network over the first decade, and finally discuss perspectives.

RESULTS

The labelling of 24 centers in the CRIOAc network allowed for a meshing of the territory, with the possibility of management of complex BJI in each region of France. A dedicated secure national online information system was designed and used to facilitate decision-making during multidisciplinary consultation meetings. Since October 2012 to June 2017, 4553 multidisciplinary consultation meetings have been performed in the structures belonging to the network, with 34,607 cases discussed in 19,961 individual. Prosthetic joint infections represented 38% (7585/19,961) of all BJIs. Among all the cases discussed, the rate of complexity was of 61% (21,110/34,607) (related to antibiotic resistance, infection recurrence, patient co morbidities). A national scientific meeting was created and a national postgraduate diploma in the field of BJI was launched in 2014. The promotion of education, clinical research and interactivity between each academic discipline and between each labeled centers across the country has synergized the strengths and have greatly facilitated the management of patients with BJI.

DISCUSSION

The setting up of the CRIOAc network in France took time, and has a cost for the French Ministry of Health. However, this network has greatly facilitated the management of BJI in France, and allowed to concentrate the management of complex BJI in centers that have significantly gained skills. There is, to our knowledge, no other exemple of such nationwide network in the field of BJI.

LEVEL OF EVIDENCE

IV, case series without control group.

Relevance of Modified Debridement-Irrigation, Antibiotic Therapy and Implant Retention Protocol for the Management of Surgical Site Infections: A Series of 1694 Instrumented Spinal Surgery

Introduction: Management of surgical site infections (SSI) after instrumented spinal surgery remains controversial. The debridement-irrigation, antibiotic therapy and implant retention protocol (DAIR protocol) is safe and effective to treat deep SSI occurring within the 3 months after instrumented spinal surgery.

Methods: This retrospective study describes the outcomes of patients treated over a period of 42 months for deep SSI after instrumented spinal surgery according to a modified DAIR protocol.

Results: Among 1694 instrumented surgical procedures, deep SSI occurred in 46 patients (2.7%): 41 patients (89%) experienced early SSI (< 1 month), 3 (7%) delayed SSI (from 1 to 3 months), and 2 (4%) late SSI (> 3months). A total of 37 patients had a minimum 1 year of follow-up; among these the modified DAIR protocol was effective in 28 patients (76%) and failed (need for new surgery for persistent signs of SSI beyond 7 days) in 9 patients (24%). Early second-look surgery (≤ 7days) for iterative debridement was performed in 3 patients, who were included in the cured group. Among the 9 patients in whom the modified DAIR protocol failed, none had early second-look surgery; 3 (33%) recovered and were cured at 1 year follow-up, and 6 (66%) relapsed. Overall, among patients with SSI and a minimum 1 year follow-up, the modified DAIR protocol led to healing in 31/37 (84%) patients.

Conclusions: The present study supports the effectiveness of a modified DAIR protocol in deep SSI occurring within the 3 months after instrumented spinal surgery. An early second-look surgery for iterative debridement could increase the success rate of this treatment.

A practical approach to tuberculosis diagnosis and treatment in liver transplant recipients in a low-prevalence area

Solid organ transplant candidates/recipients are at risk of mycobacterial infections. Although guidelines on the management of latent tuberculosis infection and active tuberculosis are available for solid organ transplant recipients, limited guidance focuses on end-stage liver disease or liver transplant recipients who require management in a referral center. Therapeutic challenges arise from direct antituberculosis drug-related hepatotoxicity, and substantial metabolic interactions between immunosuppressive and antituberculosis drugs. Another issue is the optimal timing of therapy with regards to the time of transplantation. This review focuses on the importance of tuberculosis screening with immunological tests, challenges in the diagnosis, management, and treatment of latent tuberculosis infection and active tuberculosis, as well as risk assessment for active tuberculosis in the critical peri-liver transplantation period. We detail therapeutic adjustments required for the management of antituberculosis drugs in latent tuberculosis infection and active tuberculosis, particularly when concomitantly using rifampicin and immunosuppressive drugs.

1210. Staphylococcal Acute Post-Operative Prosthetic Joint Infection (PJI) Treated With “DAIR” (Debridement and Implant Retention) and Impact of Rifampin: A Retrospective Cohort Study in France

Background

Staphylococci are the most frequent bacteria in PJI. In patients with acute PJI (i.e., <1 month following the implantation), DAIR with exchange of removal components followed by a combination of antibiotics including rifampin (RMP) (particularly RMP + fluoroquinolone) are recommended. Unfortunately, some patients could not receive RMP due to drug–drug interaction or stopped it due to an adverse event. Finally, it is unclear whether the dose and the duration of RMP influenced the prognosis.

Methods

Retrospective cohort study in four hospitals including patients with staphylococcal acute post-operative PJI treated with DAIR in 2011–2016. Univariate and multivariate Cox analysis and Kaplan–Meier curves were used to determine the risk factors for treatment failure.

Results

Seventy-nine patients were included (median age: 71 years [IQR 53–89]; 55 men [69.6%]; median ASA score: 2 [IQR 2–3]). Cultures revealed 65 (82%) S. aureus and 15 (19%) coagulase negative staphylococci infections, including 14 methicillin-resistant strains (18%). Among all isolates, only two (3%) were resistant to RMP and 16 (20%) were resistant to fluoroquinolone. The median duration of antimicrobial therapy was 92 days (IQR 31–152). Only 59 patients received RMP (75%), and 35 (44%) the combination RMP + fluoroquinolone. Median duration of RMP was 57 days (IQR 16–86) and median dose 14.6 mg/kg/d (IQR 13–17). Forty patients (51%) received RMP in the first 2 weeks and 43 patients (54%) received at least 2 weeks of RMP. Six patients (8%) developed an adverse event leading to RMP interruption. During a median follow-up of 443 days (IQR 220–791), 21 patients (27%) experienced a treatment failure including 12 persistence of the initial pathogen (57%) and nine superinfections (43%). An ASA score >2 (OR 2.8; 95% CI 1.26–6.15), the use of RMP (OR 0.4; 95% CI 0.71–0.95) and the duration of RMP treatment (OR 0.83; 95% CI 0.75–0.92 per week of treatment) were significant determinants of the outcome (but not methicillin-resistance). Receiving >2 weeks of RMP prevented the failure, but an introduction during the first 2 weeks did not influence the outcome.

Conclusion

In patients with staphylococcal acute PJI, the use of RMP and its duration strongly influenced the prognosis. As 25% of patients could not receive RMP, new drugs with anti-biofilm activity are required.

Disclosures

All authors: No reported disclosures.

Salvage Debridement, Antibiotics and Implant Retention ("DAIR") With Local Injection of a Selected Cocktail of Bacteriophages: Is It an Option for an Elderly Patient With Relapsing Staphylococcus aureus Prosthetic-Joint Infection?

Local injection of a bacteriophages mix during debridement, antibiotics and implant retention ("DAIR") was performed to treat a relapsing Staphylococcus aureus chronic prosthetic joint infection (PJI). This salvage treatment was safe and associated with a clinical success. Scientific evaluation of the potential clinical benefit of bacteriophages as antibiofilm treatment in PJI is now feasible and required.

Erysipelas or cellulitis with a prosthetic joint in situ

We describe a case of a 60-year old male who developed an acute prosthetic joint infection (PJI) of the knee, secondary to erysipelas of the lower leg due to beta-hemolytic Group G streptococci. As it is unknown how often this phenomenon occurs in patients with prosthetic implants and which patients are most prone to develop this complication, we analyzed: i) the incidence of the development of a PJI in these patients and ii) the clinical characteristics of streptococcal PJI during an episode of erysipelas/cellulitis. Based on a retrospective analysis of patients with a prosthetic implant in situ presenting at the emergency department with erysipelas/cellulitis, 1 out of 10 patients developed a PJI. An additional analysis within a multicenter cohort on streptococcal PJI demonstrated in 22 patients that a secondary PJI due to erysipelas/cellulitis mostly develops in young implants (<5 years old). In 20 cases (91%), the skin infection was in the same limb as the joint prosthesis suggesting contiguous spread of bacteria. These data emphasizes the importance of preventive measures to reduce the occurrence of skin infections in patients with prosthetic implants, and if an erysipelas or cellulitis does occur, to monitor patients carefully.

Prospective Cohort Study of the Tolerability of Prosthetic Joint Infection Empirical Antimicrobial Therapy

The empirical use of vancomycin in combination with a broad-spectrum beta-lactam is currently recommended after the initial surgery of prosthetic joint infection (PJI). However, the tolerability of such high-dose intravenous regimens is poorly known. Adult patients receiving an empirical antimicrobial therapy (EAT) for a PJI were enrolled in a prospective cohort study (2011 to 2016). EAT-related adverse events (AE) were described according to the common terminology criteria for AE (CTCAE), and their determinants were assessed by logistic regression and Kaplan-Meier curve analysis. The EAT of the 333 included patients (median age, 69.8 years; interquartile range [IQR], 59.3 to 79.1 years) mostly relies on vancomycin (n = 229, 68.8%), piperacillin-tazobactam (n = 131, 39.3%), and/or third-generation cephalosporins (n = 50, 15%). Forty-two patients (12.6%) experienced an EAT-related AE. Ten (20.4%) AE were severe (CTCAE grade ≥ 3). The use of vancomycin (odds ratio [OR], 6.9; 95% confidence interval [95%CI], 2.1 to 22.9), piperacillin-tazobactam (OR, 3.7; 95%CI, 1.8 to 7.2), or the combination of both (OR, 4.1; 95%CI, 2.1 to 8.2) were the only AE predictors. Acute kidney injury (AKI) was the most common AE (n = 25; 51.0% of AE) and was also associated with the use of the vancomycin and piperacillin-tazobactam combination (OR, 6.7; 95%CI, 2.6 to 17.3). A vancomycin plasma overexposure was noted in nine (37.5%) of the vancomycin-related AKIs only. Other vancomycin-based therapies were significantly less at risk for AE and AKI. The EAT of PJI is associated with an important rate of AE, linked with the use of the vancomycin and the piperacillin-tazobactam combination. These results corroborate recent findings suggesting a synergic toxicity of these drugs in comparison to vancomycin-cefepime, which remains to be evaluated in PJI. (This study has been registered at ClinicalTrials.gov under identifier NCT03010293.).

Prolonged Cefoxitin Infusion Using Mobile Elastomeric Infusors In Outpatients With Bone And Joint Infection

We reviewed all outpatients with bone and joint infection treated with cefoxitin in continuous intravenous infusion using mobile elastomeric infusors in our regional reference center between 2014 and 2017. The stability of cefoxitin provides an interesting and well-tolerated alternative for continuous infusion in outpatients with polymicrobial bone and joint infection.