Search

Objectives: Mycobacterium abscessus has emerged as an opportunistic pathogen responsible for lung infections, especially in cystic fibrosis patients. In spite of the production of the broad-spectrum β-lactamase BlaMab, the carbapenem imipenem is recommended in the initial phase of the treatment of pulmonary infections. Here, we determine whether the addition of vaborbactam, a second-generation β-lactamase inhibitor belonging to the boronate family, improves the activity of β-lactams against M. abscessus., Methods: The activity of β-lactams, alone or in combination with vaborbactam, was evaluated against M. abscessus CIP104536 by determining MICs, time-killing and intramacrophage activity. Kinetic parameters for the inhibition of BlaMab by vaborbactam were determined by spectrophotometry., Results: The combination of vaborbactam (8 mg/L) with β-lactams decreased more than 8 times the MIC of amoxicillin (from >1024 to 128 mg/L) and 2 times the MICs of meropenem (from 16 to 8 mg/L) and imipenem (from 4 to 2 mg/L). The reduction of the MICs was less than that obtained with avibactam at 4 mg/L for amoxicillin (from >1024 to 16 mg/L, more than 64 times less) and for meropenem (from 16 to 4 mg/L, 4 times less). In vitro and intracellularly, M. abscessus was not killed by the meropenem/vaborbactam combination, in spite of significant in vitro inhibition of BlaMab by vaborbactam., Conclusions: Inhibition of BlaMab by vaborbactam decreases the MIC of β-lactams, including that of meropenem. As meropenem/vaborbactam is clinically available, this combination offers an alternative therapeutic option that should be evaluated for the treatment of pulmonary infections due to M. abscessus., (© The Author(s) 2024. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Introduction: Pneumonia is one of the most common indications for antibiotic. Shortening the duration of antibiotic therapy should help reduce bacterial resistance. To date, three randomized control trials have shown non-inferiority of short courses of antibiotic therapy (3 days) compared with 7 days in non-severe pneumonia. The aim of this study was to assess this strategy in real life., Method: This retrospective observational cohort study included all patients with pneumonia hospitalized in an internal medical ward from 11/01/2022 to 05/31/2023. We implemented the strategy based on early discontinuation of antibiotic therapy in patients with pneumonia who were clinically stable after 3 days of β-lactam treatment., Results: Among 49 patients included, median age was 72, median antibiotic duration was 4 days (IQR 3-6), and cure rate at D30 was 88 %. At day 30, we observed one death (2 %), four new antibiotic therapy (9 %), and two new hospitalisation (5 %), among five immunosuppressed patients. Among immunosuppressed patients (n=17; 35 %), failure rate was three times higher in case of short antibiotic courses (3/8; 38 %) than long antibiotic courses (1/7; 14 %)., Conclusion: Strategy based on early discontinuation of antibiotic therapy in immunocompetent patients with pneumonia who were clinically stable after 3 days of β-lactam treatment is safe, and easy to implement in a medical ward., (Copyright © 2024 Société Nationale Française de Médecine Interne (SNFMI). Published by Elsevier Masson SAS. All rights reserved.)

Background: Bacterial peritonitis (BP) in patients with gastrointestinal (GI) cancer has been poorly described, and its prevalence is unknown., Objectives: This study aimed to evaluate in patients with both GI cancer and ascites the prevalence of BP, associated features, mechanisms, prognosis, and the diagnostic performance of neutrophil count in ascites., Design: A retrospective, multicenter, observational study., Methods: All patients with GI cancer and ascites who underwent at least one paracentesis sample analyzed for bacteriology over a 1-year period were included. BP was defined by a positive ascites culture combined with clinical and/or biological signs compatible with infection. Secondary BP was defined as BP related to a direct intra-abdominal infectious source., Results: Five hundred fifty-seven ascites from 208 patients included were analyzed. Twenty-eight patients had at least one episode of BP and the annual prevalence rate of BP was 14%. Among the 28 patients with BP, 19 (65%) patients had proven secondary BP and 17 (59%) patients had multi-microbial BP, mainly due to Enterobacterales . A neutrophil count greater than 110/mm 3 in ascites had negative and positive predictive values of 96% and 39%, respectively, for the diagnosis of BP. The median survival of patients with BP was 10 days (interquartile range 6-40) after the diagnosis., Conclusion: BP is not rare in patients with GI cancer and is associated with a poor short-term prognosis. When a patient with GI cancer is diagnosed with BP, a secondary cause should be sought. Further studies are needed to better define the best management of these patients., Competing Interests: The authors declare that there is no conflict of interest., (© The Author(s), 2024.)

Background: Post-surgical spinal infections (pSSIs) are a serious complication of spinal surgeries, with Staphylococcus spp. being one of the most prominent bacteria identified. Optimal antimicrobial therapy for staphylococcal spinal infections without spinal implants is not well documented., Methods: This single center retrospective 7-year observational study described and compared the outcome (treatment failure or mortality rate one year after diagnosis) of 20 patients with staphylococcal-implant-free pSSI treated with single or combination antibiotics., Results: Median duration of treatment was 40 days (IQR 38-42), with 6 days (IQR 5-7) on intravenous antibiotics and 34 days (IQR 30-36) on oral therapy. Four patients (20%) underwent new surgical debridement, all due to surgical failure, and 1 patient died within the first year without significant differences between both treatment group., Conclusion: This study raises the possibility of single antibiotic therapy for patients with implant-free post-surgical spinal infections due to Staphylococcus spp., (© 2024. The Author(s).)

Purpose: The duration of antibiotic treatment for prosthetic valve endocarditis caused by Streptococcus spp. is largely based on clinical observations and expert opinion rather than empirical studies. Here we assess the impact of a shorter antibiotic duration., Objectives: To assess the impact of antibiotic treatment duration for streptococcal prosthetic valve endocarditis on 12-month mortality as well as subsequent morbidity resulting in additional cardiac surgical interventions, and rates of relapse and reinfection., Methods: This retrospective multisite (N= 3) study examines two decades of data on patients with streptococcal prosthetic valve endocarditis receiving either 4 or 6 weeks of antibiotics. Overall mortality, relapse, and reinfection rates were also assessed for the entire available follow-up period., Results: The sample includes 121 patients (median age 72 years, IQR [53; 81]). The majority (74%, 89/121) received a ß-lactam antibiotic combined with aminoglycoside in 74% (89/121, median bi-therapy 5 days [1; 14]). Twenty-eight patients underwent surgery guided by ESC-guidelines (23%). The 12-month mortality rate was not significantly affected by antibiotic duration (4/40, 10% in the 4-week group vs 3/81, 3.7% in the 6-week group, p=0.34) or aminoglycoside usage (p=0.1). Similarly, there were no significant differences between the 2 treatment groups for secondary surgical procedures (7/40 vs 21/81, p=0.42), relapse or reinfection (1/40 vs 2/81 and 2/40 vs 5/81 respectively)., Conclusions: Our study found no increased adverse outcomes associated with a 4-week antibiotic duration compared to the recommended 6-week regimen. Further randomized trials are needed to ascertain the optimal duration of treatment for streptococcal endocarditis., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: Treating patients with infective endocarditis (IE) due to streptococci and enterococci currently involves high-dosage antibiotics. Recent literature suggests a 30%-70% diffusion rate could be extrapolated to human heart valve tissue. The objective of this study was to evaluate the diffusion coefficient of amoxicillin in heart valve tissue of patients operated for IE., Methods: Adult patients were prospectively included that underwent surgery at the European Hospital Georges Pompidou for IE due to streptococci and enterococci and had previous IV amoxicillin treatment. Plasma (taken 48 h preoperatively) and heart valve tissue amoxicillin concentrations were measured with a validated LC-MS/MS method. The MIC values of amoxicillin were measured for all available isolates., Results: Seventeen patients were included. Eleven (64.7%) patients had native valve IE and six (35.3%) had prosthetic valve IE. Fourteen IE cases (82.4%) were due to streptococci, one (5.9%) was due to enterococci and two (11.8%) were Haemophilus spp, Aggregatibacter actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae group infections. Median (IQR) amoxicillin dose administered was 10.5 (8.0-12.0) g/day corresponding to 138.2 (112.5-160.0) mg/kg/day. The median amoxicillin plasma concentrations pre-surgery and intra-tissular weighted concentrations were 31.9 (25.9-51.9) mg/L and 19.0 (7.9-31.4) µg/g, respectively. Median tissue/plasma concentration ratio was 0.47 (0.24-0.67), with a median amoxicillin plasma/MIC ratio of 487 (179-745), and median amoxicillin tissue/MIC ratio of 42 (14-116)., Conclusions: With a significant diffusion coefficient, amoxicillin dosage in heart valve tissues showed a concentration/MIC ratio well above current recommendations for bactericidal activity. Our study suggests that lower doses can be considered for susceptible bacteria., (© The Author(s) 2023. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Diagnostic uncertainty (DU) is frequent in infectious diseases (ID), being recorded in 10% to over 50% of patients. Herein, we show that in several fields of clinical practice, high rates of DU are constant over time. DUs are not taken into account in guidelines, as therapeutic propositions are based on an established diagnosis. Moreover, while other guidelines underline the need for rapid broad-spectrum antibiotic therapy for patients with sepsis, many clinical conditions mimic sepsis and lead to unnecessary antibiotic therapy. Considering DU, many studies have been carried out to look for relevant biomarkers of infections, which also attest to non-infectious diseases mimicking infections. Therefore, diagnosis is often primarily a hypothesis, and empirical antibiotic therapy should be reassessed when microbiological data are available. However, other than for urinary tract infections or unexpected primary bacteremia, the high frequency of sterile microbiological samples implies that DU remains central in follow-up, which does not facilitate clinical management or antibiotic optimization. The main way to resolve the therapeutic challenge of DU could be to precisely describe the latter through a consensual definition that would facilitate consideration of DU and its mandatory therapeutic implications. A consensual definition of DU would also clarify responsibility and accountability for physicians in the antimicrobial approval process and l provide an opportunity to instruct their students in this large field of medical practices and to productively conduct relevant research., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Peptidoglycan is an essential component of the bacterial cell envelope that sustains the turgor pressure of the cytoplasm, determines cell shape, and acts as a scaffold for the anchoring of envelope polymers such as lipoproteins. The final cross-linking step of peptidoglycan polymerization is performed by classical d,d-transpeptidases belonging to the penicillin-binding protein (PBP) family and by l,d-transpeptidases (LDTs), which are dispensable for growth in most bacterial species and whose physiological functions remain elusive. In this study, we investigated the contribution of LDTs to cell envelope synthesis in Pseudomonas aeruginosa grown in planktonic and biofilm conditions. We first assigned a function to each of the three P. aeruginosa LDTs by gene inactivation in P. aeruginosa, heterospecific gene expression in Escherichia coli, and, for one of them, direct determination of its enzymatic activity. We found that the three P. aeruginosa LDTs catalyze peptidoglycan cross-linking (Ldt Pae1 ), the anchoring of lipoprotein OprI to the peptidoglycan (Ldt Pae2 ), and the hydrolysis of the resulting peptidoglycan-OprI amide bond (Ldt Pae3 ). Construction of a phylogram revealed that LDTs performing each of these three functions in various species cannot be assigned to distinct evolutionary lineages, in contrast to what has been observed with PBPs. We showed that biofilm, but not planktonic bacteria, displayed an increase proportion of peptidoglycan cross-links formed by Ldt Pae1 and a greater extent of OprI anchoring to peptidoglycan, which is controlled by Ldt Pae2 and Ldt Pae3 . Consistently, deletion of each of the ldt genes impaired biofilm formation and potentiated the bactericidal activity of EDTA. These results indicate that LDTs contribute to the stabilization of the bacterial cell envelope and to the adaptation of peptidoglycan metabolism to growth in biofilm. IMPORTANCE Active-site cysteine LDTs form a functionally heterologous family of enzymes that contribute to the biogenesis of the bacterial cell envelope through formation of peptidoglycan cross-links and through the dynamic anchoring of lipoproteins to peptidoglycan. Here, we report the role of three P. aeruginosa LDTs that had not been previously characterized. We show that these enzymes contribute to resistance to the bactericidal activity of EDTA and to the adaptation of cell envelope polymers to conditions that prevail in biofilms. These results indicate that LDTs should be considered putative targets in the development of drug-EDTA associations for the control of biofilm-related infections., Competing Interests: The authors declare no conflict of interest.

The objective of this study was to evaluate the effectiveness of the recommended treatment for endovascular infections due to Coxiella burnetii. This single-center retrospective study was conducted in 13 patients with endovascular infection due to C. burnetii between January 2001 and December 2020 for a definite or possible endovascular infection due to C. burnetii with a minimum follow-up of 18 months post-infection. Clinical and biological data, including serology, blood and tissue PCR results, doxycycline and hydroxychloroquine assays were collected. Among the 13 patients, 11 had endocarditis (8 definite and 3 possible) and 2 had a vascular infection. At the time of diagnosis, fever was present in only 46% of cases. In case of endocarditis, 73% of patients had a pathological echocardiography. Biologically, the CRP level was low (52 mg/l ± 44). Autoimmune antibodies (antinuclear factor, neutrophil anticytoplasm) were present in 23% of patients. At the time of diagnosis, tissue PCR was very sensitive (100%) unlike blood or serum (29%). Blood levels of doxycycline and hydroxychloroquine were within expected values. Only one patient experienced treatment failure at two years, requiring surgery. For the 7 patients whose phase I IgG titres fell below 1/800, a minimum of 18 months of treatment was necessary. In the long term, the clinical and biological cure was 100% and 92% respectively, underlining the importance of monitoring the serum dosages of doxycycline and hydroxychloroquine. Given its sensitivity, tissue PCR could be added to the major Duke criteria., (Copyright © 2022 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

We aimed to describe the outcome of totally implantable venous-access port (TIVAP)-related infections due to Gram-negative aerobic bacilli (Pseudomonas aeruginosa and other Pseudomonas spp., Acinetobacter spp., and Stenotrophomonas maltophilia), or GNAB, and assess the safety of conservative treatment. We conducted a retrospective study in a French teaching hospital, from January 2016 to December 2020, including adult patients treated for TIVAP-related infection due to GNAB. Success of conservative treatment was defined as a functional TIVAP 3 months after infection with no recurrence. We performed a bivariate analysis and analyzed causes for treatment failure. We included 68 patients (53 TIVAP-related bloodstream infections, 11 TIVAP-related infections, and 4 probable TIVAP-related infections) due to GNAB, mostly P. aeruginosa (50/68, 74%). TIVAP removal was initially decided for 49/68 patients (72%). Among the 19/68 (28%) patients with conservative treatment (all for infections caused by P. aeruginosa), 5/19 (26%) had successful treatment, 7/19 (37%) experienced failure (without sepsis or septic shock), 6/19 (32%) died within 3 months without TIVAP removal and no signs of infection recurrence, and 1 patient had TIVAP removal as it was no longer required. TIVAP-related infections caused by GNAB frequently require TIVAP removal. Conservative treatment can be performed in selected patients with a non-complicated infection caused by P. aeruginosa, who can benefit from the continuation of antineoplastic chemotherapy or palliative care. Treatment failures were not associated with sepsis or septic shock., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Treatment of multidrug-resistant tuberculosis with combinations of carbapenems and β-lactamase inhibitors carries risks for dysbiosis and for the development of resistances in the intestinal microbiota. Using Escherichia coli producing carbapenemase KPC-2 as a model, we show that carbapenems can be modified to obtain drugs that are inactive against E. coli but retain antitubercular activity. Furthermore, functionalization of the diazabicyclooctanes scaffold provided drugs that did not effectively inactivate KPC-2 but retained activity against Mycobacterium tuberculosis targets.

Appropriate prescribing of anti-infectives is a public health challenge. In our hospital, clinical microbiologists (clinical microbiology mobile unit, UMMc) and clinical pharmacists (clinical pharmacy, PHAc) carry out interventions on anti-infective prescriptions to improve practices. Our main objective was to evaluate the acceptance of UMMc and PHAc interventions on anti-infective prescriptions by quantifying the rate of prescription change 24 h after intervention. The secondary objective was to characterize the type of intervention and associate the rate of change for each. All prescriptions are computerized, and interventions traced via DxCare® software, which feeds a local data warehouse (HEGP-CDW). This descriptive, retrospective, single-center, uncontrolled study was conducted from January 2015 to December 2018. The data were extracted over this period from the data warehouse and analyzed using R software. UMMc interventions were accepted 72.2% of the time and PHA interventions 87.3%. The types of interventions found were mostly dose adjustments (61.1% for the UMMc and 54.2% for the PHAc) and proposals to change or stop a drug. Interventions have an impact on anti-infective prescriptions and are generally followed by clinicians. For the category "discontinuation of a molecule", almost half of the advice from the UMMc was refused. The collaboration between the UMMc and PHAc should be reinforced to improve acceptance., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The World Health Organisation (WHO) has designated antibiotic resistance as one of the most challenging public health threats of the 21st century. Production of β-lactamase enzymes by Gram-negative bacteria is the main mechanism of resistance to β-lactam (BL), the most widely used antibiotic in clinics. In an attempt to neutralise the hydrolytic activity of these enzymes, β-lactamase inhibitors (BLIs) have been developed. First-generation BLIs include clavulanic acid, sulbactam and tazobactam. However, none of them cover all β-lactamase classes, and an increasingly wide panel of inhibitor-resistant bacterial strains has developed. Second-generation BLIs function via different mechanisms and were developed by novel scaffolds from which diazabicyclooctane (DBOs) and boronic acids have emerged. In this paper, we provide descriptions of promisor second-generation β-lactamase inhibitors, such as avibactam, vaborbactam and boronic acids, as well as several BL-BLI combinations that have been designed. While some combinations are now being used in clinical practice, most are presently limited to clinical trials or pre-clinical studies. In this paper, we emphasise the continuous need to develop novel and different BLIs to keep up with the multidrug-resistant bacteria that arise. At this time, however, second-generation BLIs constitute a promising and effective approach., (Copyright © 2020. Published by Elsevier Masson SAS.)

Objective: To assess the performance of the new rapid antimicrobial susceptibility testing (AST) QMAC-dRAST V2.5 system., Methods: ASTs were performed using QMAC-dRAST-V2.5 and a disk diffusion method, directly from positive blood bottles with Gram-negative bacteria. Discrepancies between the results obtained using the two methods were categorized into very major errors (VME, S with dRAST vs. R with disk diffusion), major errors (ME, R vs. S, respectively), minor errors (mE, S vs. I or I vs. R, respectively), and very minor errors (Vme, I vs. S or R vs. I, respectively). For each AST, results were recorded after 4, 5, and 6h of incubation., Results: From 106 bacteremia, 1416 individual AST results were obtained. Overall agreement between results using the two methods was 91%, ranging from 76.9% to 99.1% depending upon the antibiotic, with 128 errors, i.e. 14/1416 (1%) VME, 59/1416 (4.2%) ME, 25/1416 (1.8%) mE and 30/1416 (2.1%) Vme. VMEs were encountered for Klebsiellasp and Serratia marcescens isolates with low-level piperacillin and amikacin resistance, respectively. Using the integrated QMAC-dRAST-V2.5 expert system, all 14 VMEs and 3 mEs were eliminated, leading to 92.2% categorical agreement. After 45min of pre-incubation in the QMAC-dRAST-V2.5 device, 22.2% of the 1416 AST results were obtained after 4h, an additional 31.4% after 5h and a further 46.3% after 6h., Conclusion: QMAC-dRAST-V2.5 is an optimized version of QMAC-dRAST V2.0, particularly with respect to utilization of an expert system and reduced TAT according to the antibiotic tested., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Introduction: Attendance at face-to-face courses is low in the 2nd and 3rd years of medical school in France, possibly because of a lack of interactivity. We used Moodle (an open-source course management system) to introduce blended learning on Infectious Diseases and Microbiology through interactive quizzes and sessions of online-based continuous assessment. This pre-post observational study assessed changes in students' attendance and student as well as teacher satisfaction., Methods: During the 2017-2018 academic session of Infectious Diseases and Microbiology, we used Moodle to include interactive quizzes during courses and to organize five continuous assessment sessions. Pre-post comparisons (2017-2018 vs. 2016-2017) were performed for the following outcomes: attendance rate, satisfaction questionnaire and exam performance. In addition, the students' and teachers' perception of Moodle-based interactive quizzes and continuous assessment sessions in 2017-2018 was assessed with Likert-like scales, closed and open-ended questions. A thematic analysis of the free comments was performed through inductive coding by two coders., Results: In 2017-2018 vs. 2016-2017, mean (±SD) attendance rate was higher [12.5 (±7.2) % vs. 7.9 (±3.5) % of students, P<0.001] and clinical case-based courses, which encompassed 93% of Moodle-based courses in 2017-18, were more frequently considered to improve teaching and learning (81.9% vs. 73.8%, P=0.01). Students more frequently judged the teaching organization and structure to be adequate (85.5% vs. 80.2%, p=0.03) and more frequently recommended to next-year students that they attend courses (96.1% vs. 42.1%, P<0.001)., Conclusion: Using Moodle for blended learning on Infectious Diseases and Microbiology improved student satisfaction and attendance at face-to-face courses., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Aims: Infective endocarditis is a severe infection which can occur in adult patients with congenital heart disease. We aimed to determine outcomes and risk factors of death in adult congenital heart disease and to investigate differences with infective endocarditis in non-congenital heart disease., Methods and Results: Between March 2000 and June 2018, 671 consecutive episodes of infective endocarditis in adult patients were retrospectively recorded. Cases were classified according to the modified Duke classification. All adult congenital heart disease cases were managed by infectious disease specialists and adult congenital heart disease cardiologists. During this period, 142 infective endocarditis episodes (21%) occurred in adult congenital heart disease patients with simple (46.5%), moderate (21.1%), or complex (32.4%) congenital heart disease. In-hospital mortality was 12.7%. The strongest predictive factors of in-hospital death in multivariate analysis were complexity of congenital heart disease (odds ratio (OR) 8.02, 95% confidence interval (CI) 1.53-42.07), age (OR 1.05, 95% CI 1.00-1.19) and white blood cell count 12 g/L or greater (OR 8.72, 95% CI 2.42-31.43). Patients with congenital heart disease were significantly younger (median age 36 vs. 67 years, P <0.001), had undergone more redo cardiac surgeries (35.7% vs. 11.3%, P <0.01) and presented with more right-sided infective endocarditis (39.4% vs. 7.9%, P <0.01) than patients without congenital heart disease. Congenital heart disease was associated with two-fold lower in-hospital mortality rates (OR 0.37, 95% CI 0.19-0.74), independently of age, gender, obesity, renal function and side of infective endocarditis., Conclusion: Although mortality associated with infective endocarditis is lower in adult patients with congenital heart disease than patients without congenital heart disease, infective endocarditis mortality is particularly high in patients with complex congenital heart disease. Education and prevention about the risk of infective endocarditis is essential, especially in this group.

Bacteriophages are a promising therapeutic strategy among cystic fibrosis and lung-transplanted patients, considering the high frequency of colonization/infection caused by pandrug-resistant bacteria. However, little clinical data are available regarding the use of phages for infections with Achromobacter xylosoxidans . A 12-year-old lung-transplanted cystic fibrosis patient received two rounds of phage therapy because of persistent lung infection with pandrug-resistant A. xylosoxidans . Clinical tolerance was perfect, but initial bronchoalveolar lavage (BAL) still grew A. xylosoxidans . The patient's respiratory condition slowly improved and oxygen therapy was stopped. Low-grade airway colonization by A. xylosoxidans persisted for months before samples turned negative. No re-colonisation occurred more than two years after phage therapy was performed and imipenem treatment was stopped. Whole genome sequencing indicated that the eight A. xylosoxidans isolates, collected during phage therapy, belonged to four delineated strains, whereby one had a stop mutation in a gene for a phage receptor. The dynamics of lung colonisation were documented by means of strain-specific qPCRs on different BALs. We report the first case of phage therapy for A. xylosoxidans lung infection in a lung-transplanted patient. The dynamics of airway colonization was more complex than deduced from bacterial culture, involving phage susceptible as well as phage resistant strains.

Objectives: The primary objective was to assess the value of the European Society of Cardiology (ESC) criteria, including 18 F-fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG-PET/CT) in prosthetic valve infective endocarditis (PVE). Secondary objectives were: 1) to assess the reproducibility of 18 F-FDG-PET/CT; 2) to compare its diagnostic value with that of echocardiography; and 3) to assess the diagnostic value of the presence of a diffuse splenic uptake BACKGROUND: 18 F-FDG PET/CT has been added as a major criterion in the ESC 2015 infective endocarditis (IE) guidelines, but the benefit of the ESC criteria has not been prospectively compared with the conventional Duke criteria., Methods: Between 2014 and 2017, 175 patients with suspected PVE were prospectively included in 3 French centers. After exclusion of patients with uninterpretable 18 F-FDG PET/CT, 115 patients were evaluated, including 91 definite and 24 rejected IE, as defined by an expert consensus., Results: Cardiac uptake by 18 F-FDG PET/CT was observed in 67 of 91 patients with definite PVE and 6 with rejected IE (sensitivity 73.6% [95% confidence interval (CI): 63.3% to 82.3%], specificity 75% [95% CI: 53.3% to 90.2%]). The ESC 2015 classification increased the sensitivity of Duke criteria from 57.1% (95% CI: 46.3% to 67.5%) to 83.5% (95% CI: 74.3% to 90.5%) (p < 0.001), but decreased its specificity from 95.8% (95% CI: 78.9% to 99.9%) to 70.8% (95% CI: 48.9% to 87.4%). Intraobserver reproducibility of 18 F-FDG PET/CT was good (kappa = 0.84) but interobserver reproducibility was less satisfactory (kappa = 0.63). A diffuse splenic uptake was observed in 24 (20.3%) patients, including 23 (25.3%) of definite PVE, and only 1 (4.2%) rejected PVE (p = 0.024)., Conclusions: 18 F-FDG PET/CT is a useful diagnostic tool in suspected PVE, and explains the greater sensitivity of ESC criteria than Duke criteria. However, 18 F-FDG PET/CT also presents with important limitations concerning its feasibility, specificity, and reproducibility. Our study describes for the first time a new endocarditis criterion, that is, the presence of a diffuse splenic uptake on 18 F-FDG PET/CT., Competing Interests: Author Disclosures This study was supported by grants from the PHRC (projet hospitalier de recherche clinique) PHRC 2012 n° 2013-01 et -la Fondation Coeur et Recherche. The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: In spinal surgery, incidence of surgical site infections (SSI) is estimated between 1 and 10%. It results in increased morbidity, mortality and cost of management. Individual Staphylococcus aureus (SA) decolonization has already proved efficiency to prevent those events in various surgical domains. The aim of this study was to evaluate a strategy of prevention of SSI and in particular the decolonization of the nasal carriage of SA by a protocol with Mupirocin application., Methods: We conducted a bicentric observational study on 5314 spinal surgery patients over a seven-year period. In both center, we compared periods before and after implementation of two measures: modification of antibioprophylaxis and staphylococcus decolonization. Homogeneity of the different samples of patients was assessed through measure of individual and surgical variables. We measured monthly incidence of SSI and evaluated its evolution in order to assess efficiency of these interventions., Results: The incidence of SSI decreased by half, from 7.3% to 3% at the Beaujon Hospital and from 8.3% to 3.9% at the Georges-Pompidou European Hospital (GPEH). We do not observe any significant decrease of SA rate in these SSI., Conclusion: We believe that Staphylococcus aureus decolonization should be recommended in spinal surgery, and should be combined with an overall improvement of the quality of care., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Introduction: Left-sided infective endocarditis (IE) is a serious infection with a heavy burden for patients and healthcare system. Oral switch after initial intravenous antibiotic therapy may reduce costs and improve patients' discomfort without increasing unfavourable outcomes. We describe the methodology of two simultaneously conducted open-label randomised trials aiming to assess non-inferiority of oral switch as compared with entirely intravenous antibiotic therapy for the treatment of left-sided IE., Methods and Analysis: Two simultaneous multicentre open-label prospective randomised trials assessing non-inferiority of oral switch during antibiotic treatment as compared with entirely intravenous therapy in patients with left-sided IE are ongoing. One trial is dedicated to left-sided IE caused by multisusceptible staphylococci (Relais Oral Dans le traitement des Endocardites à staphylocoques ou streptOcoques (RODEO)-1) and the other is dedicated to left-sided IE caused by susceptible streptococci or enterococci (RODEO-2). It is planned to randomise 324 patients in each trial after an initial course of at least 10 days of intravenous antibiotic therapy either to continue intravenous antibiotic therapy or to switch to oral antibiotic therapy. The primary outcome is treatment failure within 3 months after the end of antibiotic treatment, a composite outcome defined by all-cause death and/or symptomatic embolic events and/or unplanned valvular surgery and/or microbiological relapse (with the primary pathogen). Secondary outcomes include patient quality of life, echocardiographic outcome, costs and efficiency associated with IE care. Statistical analysis will be performed with a non-inferiority margin of 10% and a one-sided 2.5% type I error., Ethics and Dissemination: Written informed consent will be obtained from all participants. This study was approved by Tours Research ethics committee (CPP TOURS-Region Centre-Ouest 1, 2015-R26, 23 February 2016). Study findings will be published in peer-reviewed journals and disseminated through presentation at relevant national and international conferences., Trial Registration Number: EudraCT Number: 2015-002371-16 and NCT02701608; NCT02701595., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Despite its efficacy and toxicity being exposure-related, levofloxacin pharmacokinetics in patients with bone and joint infections has been poorly described to date, so the possible need for a dose adjustment is unknown in this population. A prospective population pharmacokinetic study was conducted in 59 patients to answer this question. The final model consisted of a one-compartment model with first-order absorption and elimination. Mean parameter estimates (% interindividual variability) were 0.895 h -1 for the absorption rate constant (Ka), 6.10 L/h (40%) for the apparent clearance (CL/F), 90.6 L (25%) for the apparent distribution volume (V/F). Age and glomerular filtration rate (GFR), estimated by the modification of diet in renal disease formula, were related to CL/F by power models, and CL/F was found to increase for increasing GFR and decreasing age. For a similar GFR, the simulated area under the curve (AUC) was 55% higher in 70 years-old patients compared to 30 year-old patients. Based on this model, a 750 mg dose should provide an optimal exposure (AUC/ minimum inhibitory concentration (MIC) ≥100), with the possible exception of patients older than 60 years and with GFR <70 mL/min/m² who may necessitate a dose reduction, and patients with infections caused by bacteria with MIC close to 1 mg/L who may need an increase in the dose.

Background: Based on experimental studies showing synergism with β-lactams and glycopeptides, aminoglycosides have long been considered essential in the treatment of infective endocarditis (IE). However, their use is associated with a high risk of renal failure, especially in elderly patients., Aims: The aim of this narrative review was to summarize the evidence to support reducing or even avoiding the use of aminoglycosides for the treatment of IE. We also analysed data supporting the use of aminoglycosides in specific subgroup of IE patients., Sources: PubMed database was searched up to July 2019 to identify relevant studies., Contents: Recent European Guidelines reduced the use of aminoglycosides in IE, no longer recommended in Staphylococcus aureus native-valve IE, and shortened to 2 weeks for IE related to Enterococcus faecalis and streptococci with penicillin MIC >0.125 μg/mL. In addition, an alternative regimen without aminoglycosides (ampicillin or amoxicillin plus ceftriaxone) is proposed for E. faecalis. Observational studies suggested that gentamicin would not be necessary in the case of staphylococcal prosthetic valve IE as long as rifampicin is maintained. Recent clinical studies showed that for streptococcal IE, gentamicin could be restricted to isolates with penicillin MIC >0.5 μg/mL. For the empirical and definitive treatment of E. faecalis IE, amoxicillin or ampicillin plus ceftriaxone may be considered, irrespective of high-level of aminoglycoside resistance., Implications: In a scenario of progressive increase in the age and frailty of IE patients, the use of aminoglycosides can be reduced or avoided in ~90% cases. This should result in reduced incidence of renal failure, an important prognostic factor in IE., (Copyright © 2019 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

To comparatively evaluate the performance of the rapid antimicrobial susceptibility testing (AST) system QMAC-dRAST V2.0 and of standard disk diffusion in agar, AST was performed directly from 100 positive blood culture bottles with Gram-negative bacilli. AST results provided by QMAC-dRAST showed 92.9% agreement with disk diffusion method results. Discrepancies observed between results obtained with QMAC-dRAST and disk diffusion method conducted to 10 very major errors (0.8%, S with QMAC-dRAST vs R with disk diffusion method), 40 major errors (3.2%, R vs S, respectively), 15 minor errors (1.2%, S vs I or I vs R, respectively) and 23 very minors errors (1.8%, I vs S or R vs I, respectively). For very major and major errors, in only 36% of the cases did the repeat QMAC-dRAST confirm the initial result, whereas a repeat AST using disk diffusion method confirmed the initial result in 92% of cases. AST results obtained using microdilution in liquid medium confirmed those obtained with QMAC-dRAST and disk diffusion method in 4% and 89%, respectively. Repeatability and reproducibility tests performed on QMAC-dRAST using reference strains showed 94% to 100% of R/S/I categorical agreement., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Objectives: Imipenem is one of the recommended β-lactams for the treatment of Mycobacterium abscessus pulmonary infections in spite of the production of BlaMab β-lactamase. Avibactam, a second-generation β-lactamase inhibitor, was previously shown to inactivate BlaMab, but its partner drug, ceftazidime, is devoid of any antibacterial activity against M. abscessus. Here, we investigate whether relebactam, a novel second-generation inhibitor developed in combination with imipenem, improves the activity of this carbapenem against M. abscessus., Methods: The impact of BlaMab inhibition by relebactam was evaluated by determining MICs, time-kill curves and M. abscessus intracellular proliferation in human macrophages. Kinetic parameters for the inhibition of BlaMab by relebactam were determined by spectrophotometry using nitrocefin as the substrate. The data were compared with those obtained with avibactam., Results: Combination of relebactam (4 mg/L) with β-lactams led to >128- and 2-fold decreases in the MICs of amoxicillin (from >4096 to 32 mg/L) and imipenem (from 8 to 4 mg/L). In vitro, M. abscessus was not killed by the imipenem/relebactam combination. In contrast, relebactam increased the intracellular activity of imipenem, leading to 88% killing. Relebactam and avibactam similarly potentiated the antibacterial activities of β-lactams although BlaMab was inactivated 150-fold less effectively by relebactam than by avibactam., Conclusions: Inhibition of BlaMab by relebactam improves the efficacy of imipenem against M. abscessus in macrophages, indicating that the imipenem/relebactam combination should be clinically considered for the treatment of infections due to M. abscessus., (© The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: The incidence of spinal surgical site infections (SSIs) remains stable at less than 10%. Surgical reinterventions may be hampered by decubitus, treatment-related adverse events, and cost. In the context of emergence of bacterial resistance, a short duration of antimicrobial treatment is of critical importance. If the duration of treatment for SSI is currently 12 weeks, the aim of our study was to assess the efficacy of an antimicrobial treatment shortened to 6 weeks., Methods: This prospective study was carried out from November 2014 to July 2016 in an 827-bed teaching hospital. After surgical management of SSIs, patients received broad-spectrum antibiotics intravenously for 10 days and orally for the remainder, for a total of 6 weeks. Success was defined as absence of relapse, superinfection, or surgical failure at the end of treatment and at 1-year follow-up., Results: Eighty-five patients were included in this study. The median delay between initial surgery and diagnosis of SSI was 16 days. In 65 cases (76.4%), SSIs were monomicrobial; among these, Staphylococcus aureus was found in 30 cases (46%). Failure was observed in 7 cases (8.2%), with more than half caused by anaerobic bacteria., Conclusions: Surgical management of SSI followed by a 6-week antibiotic treatment is associated with favorable outcome. Anaerobic bacteria seem to play a role in the occurrence of relapses. A 6-week reduction in antibiotic treatment leads to reduction in cost and, likely, also to reduction in the emergence and spread of resistant microorganisms., (© The Author(s) 2018. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Mycobacterium abscessus infections are difficult to treat because of their resistance to many antibiotics. In vitro , tedizolid combined with imipenem displayed a moderate synergistic effect (fractional inhibitory concentration index, 0.41) but no bactericidal activity. Intracellularly, tedizolid 2 μg/ml (half of the MIC), corresponding to the peak serum concentration, increased the efficacy of imipenem at 8 and 32 μg/ml. Addition of avibactam and rifabutin, alone or in combination, improved the activity of the imipenem-tedizolid combination., (Copyright © 2019 American Society for Microbiology.)

Enterococcus faeciumd-aspartate ligase (Asl fm ) is a peptide bond-forming enzyme that is involved in the peptidoglycan assembly pathway. It catalyzes the ATP-dependent ligation of the β-carboxylate of D-Asp to the ε-amino group of L-Lys in the nucleotide precursor UDP- MurNAc-pentapeptide. The enzyme is of interest as a target of new, potential, narrow-spectrum antibiotics directed against multiresistant E. faecium. The kinetic mechanism of Asl fm has not been fully characterized. To determine it, a progress curve analysis of Asl fm catalytic process using pyruvate kinase/lactate dehydrogenase ATPase detection assay was performed. With an inspection of the shape of measured progress curves and the results of specific qualitative experiments, the Asl fm reaction mechanism was singled out. The proposed Asl fm kinetics reaction scheme was evaluated by fitting the parameters of the corresponding differential equations to progress curves using the computer program ENZO. The complete kinetic analysis result is consistent with the substrate binding order 1) ATP, 2) D-Asp, and 3) UDP-MurNAc-pentapeptide. The analysis suggests that slowly establishing non-productive equilibria between the free and ATP-bound enzyme with the participating pentapeptide are responsible for initial reaction burst followed by a steady-state period before the complete depletion of the reactant added in the lowest concentration., (Copyright © 2019 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.)

Introduction: The dramatic increase of the incidence of infections caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) has led to an increase of 50% of carbapenem consumption all around Europe in only 5 years. This favours the spread of carbapenem-resistant Gram-negative bacilli (GNB), causing life-threatening infections. In order to limit use of carbapenems for infections actually due to ESBL-PE, health authorities promote the use of rapid diagnostic tests of bacterial resistance. The objective of this work conducted in the intensive care unit (ICU) is to determine whether an early de-escalation of empirical carbapenems guided by the result of the βLACTA test is not inferior to the reference strategy of de-escalating carbapenems after the antibiogram result has been rendered., Methods and Analysis: This multicentre randomised controlled open-label non-inferiority clinical trial will include patients suffering from respiratory and/or urinary and/or bloodstream infections documented with GNB on direct examination and empirically treated with carbapenems. Empirical carbapenems will be adapted before the second dose depending on the results of the βLACTA test performed directly on the microbiological sample (intervention group) or after 48-72 hours depending on the definite antibiogram (control group). The primary outcome will combine 90-day mortality and percentage of infection recurrence during the ICU stay. The secondary outcomes will include the number of carbapenems defined daily doses and carbapenem-free days after inclusion, the proportion of new infections during ICU stay, new colonisation of patients' digestive tractus with multidrug-resistant GNB, ICU and hospital length of stay and cost-effectiveness ratio., Ethics and Dissemination: This protocol has been approved by the ethics committee of Paris-Ile-de-France IV, and will be carried out according to the principles of the Declaration of Helsinki and the Good Clinical Practice guidelines. The results of this study will be disseminated through presentation at scientific conferences and publication in peer-reviewed journals., Trial Registration Number: NCT03147807., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Non-typhoidal salmonellosis (NTS) often occurs in children with sickle-cell disease (SCD) and remains a significant cause of mortality in developing countries. However, there is lack of reports on the clinical presentation, outcome and complications of NTS in adults with SCD., Methods: We performed a chart review between 2006 and 2016 of adults SCD diagnosed with NTS in 3 referral centers monitoring approximately 3500 SCD adults., Results: Twenty-three episodes of NTS were diagnosed among 22 SCD adults. Diagnosis was challenging: 65% (n = 15/23) of patients presented with vaso-occlusive crisis (VOC) and 30% had no fever. Isolated serotypes were: ser. Enteritidis (n = 8), ser. Typhimurium (n = 6), others (n = 3). We identified two patterns of infections: (1) bacteremic NTS (n = 15) with (n = 9) or without secondary foci of infections (n = 6); (2) non-bacteremic NTS with extra-intestinal foci of infection (n = 8), including primary bones/joints infections (n = 5). Half of patients with osteo-articular localization (n = 6/13) had a previous history of osteonecrosis (n = 2) or osteomyelitis (n = 4) at the same site. Morbidity was high, 6 patients (26%) were admitted to the intensive care unit, 14 patients (61%) required RBC transfusion for VOC. Half of the episodes (n = 12) required surgery (n = 10) or interventional radiology (n = 2) to control the infection. One patient presented a relapse of NTS bacteraemia one year after the first episode., Conclusions: Besides bloodstream infections, clinical presentation of NTS in adults with SCD is non-specific at admission. A triad including bacteraemia, secondary focis of infection and bone localizations was observed in 30% of cases.

Repurposing drugs may be useful as an add-on in the treatment of Mycobacterium abscessus pulmonary infections, which are particularly difficult to cure. M. abscessus naturally produces a β-lactamase, Bla MAb , which is inhibited by avibactam. The recommended regimens include imipenem, which is hydrolyzed by Bla MAb and used without any β-lactamase inhibitor. Here, we determine whether the addition of rifabutin improves the activity of imipenem alone or in combination with avibactam against M. abscessus CIP104536. Rifabutin at 16 μg/ml was only bacteriostatic (MIC of 4 μg/ml) and was moderately synergistic in combination with imipenem (fractional inhibitory concentration [FIC] index of 0.38). Addition of rifabutin (16 μg/ml) moderately increased killing by a low (8 μg/ml) but not by a high (32 μg/ml) concentration of imipenem. Addition of avibactam (4 μg/ml) did not further increase killing by the former combination. In infected macrophages, rifabutin (16 μg/ml) increased the activity of imipenem at 8 and 32 μg/ml, achieving 3- and 100-fold reductions in the numbers of intracellular bacteria, respectively. Avibactam (16 μg/ml) improved killing by imipenem at 8 μg/ml. A 5-fold killing was obtained for a triple combination comprising avibactam (16 μg/ml) and therapeutically achievable doses of imipenem (8 μg/ml) and rifabutin (1 μg/ml). These results indicate that the imipenem-rifabutin combination should be further considered for the treatment of M. abscessus pulmonary infections in cystic fibrosis patients and that addition of a β-lactamase inhibitor might improve its efficacy. Mechanistically, the impact of Bla MAb inhibition by avibactam on antibiotic activity was assessed by comparing CIP104536 and a β-lactamase-deficient derivative., (Copyright © 2018 American Society for Microbiology.)

There is a renewed interest for β-lactams for treating infections due to Mycobacterium tuberculosis and M. abscessus because their β-lactamases are inhibited by classical (clavulanate) or new generation (avibactam) inhibitors, respectively. Here, access to an azido derivative of the diazabicyclooctane (DBO) scaffold of avibactam for functionalization by the Huisgen-Sharpless cycloaddition reaction is reported. The amoxicillin-DBO combinations were active, indicating that the triazole ring is compatible with drug penetration (minimal inhibitory concentration of 16 μg mL -1 for both species). Mechanistically, β-lactamase inhibition was not sufficient to account for the potentiation of amoxicillin by DBOs. Thus, the latter compounds were investigated as inhibitors of l,d-transpeptidases (Ldts), which are the main peptidoglycan polymerases in mycobacteria. The DBOs acted as slow-binding inhibitors of Ldts by S-carbamoylation indicating that optimization of DBOs for Ldt inhibition is an attractive strategy to obtain drugs selectively active on mycobacteria., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Acute limb ischemia related to Coxiella burnetii endocarditis is rare. We report an original case of a 68-year-old man hospitalized for recurrent acute left limb ischemia in a context of atrial flutter, which revealed C. burnetii endocarditis. This case illustrates that even if embolic events are uncommon, septic embolisms must be systematically searched for in case of C. burnetii endocarditis. Conversely, extensive etiologic explorations must be performed in case of systemic embolism. New molecular techniques represent a major step forward in infective endocarditis diagnosis. Finally, diagnosis must be suspected in case of unexplained fever, inflammatory syndrome, or embolic event, especially in patients at risk. Conversely, in case of chronic Q fever, an immunodeficiency cause must be researched., (Copyright © 2018. Published by Elsevier Inc.)

Objectives: Incidence of extended-spectrum β-lactamase-producing Gram-negative bacilli (ESBL-PE-GNB)-related infections is worryingly increasing worldwide. ESBL-PE-GNB detection directly on bronchial aspirate samples (BAS) performed for suspected pneumonia may help save empirical carbapenems. Our objectives were to optimize β-LACTA™ test (BLT) realization and evaluate BLT performance for ESBL-PE-GNB detection directly on BAS., Methods: We studied BLT technical optimization using BAS of different matrix types spiked with increasing concentrations of CTX-M-15-producing Klebsiella pneumoniae; in vitro validation of BLT diagnostic performance on 17 ESBL enzymes, belonging to CTX-M, SHV, TEM, OXA, GES, VEB and PER groups; and clinical validation of BLT performance on 126 BAS prospectively collected from seven intensive care units., Results: After optimization, BLT detected with 100% sensitivity the presence of CTX-M-15-producing K. pneumoniae spiked in sterile BAS for inoculums upon two or more GNB per field upon microscopic Gram staining examination (MGSE). The BLT accurately detected the 17 ESBLs tested at 10 6  CFU/mL and all ESBLs except Pseudomonas aeruginosa-related OXA-14 at 10 4  CFU/mL. Among the 126 BAS of the validation cohort, 21 (17%) gave positive BLT (ten in BAS positive and 11 in BAS negative on MGSE). All BLT-positive BAS grew with ESBL-PE-GNB, including five hyper-L2-producing Stenotrophomonas maltophilia strains. BLT detected ESBL-PE-GNB directly on clinical BAS positive for GNB on MGSE and/or growing with ≥10 4  CFU/mL with 100% sensitivity, specificity, and positive and negative predictive values., Conclusions: BLT is an accurate tool for ESBL-PE-GNB detection directly on BAS. Further studies are needed to evaluate the impact of BLT-guided early antimicrobial de-escalation strategies., (Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Purpose: The aim of this study was to assess if use of the β LACTA test (BLT) for extended-spectrum beta-lactamase (ESBL) detection and/or early bacterial identification by mass spectrometry (MALDI-TOF MS) improves therapeutic decision-making when combined with advice from the antimicrobial stewardship team (AMST) for the management of Gram-negative bacillary (GNB) bacteraemia., Methods: Prospective observational theoretical study that included patients with GNB bacteraemia during a 6-month period. We compared, against the antimicrobial choice of the local AMST as informed of the Gram-stain result, a hypothetical choice, i.e. one AMST would have made had it been informed of the MALDI-TOF MS results only (option H) with the actual choice AMST made after being informed of the combined MALDI-TOF MS and BLT results (option A).Results/Key findings. A total of 131 episodes of GNB bacteraemia were included. Options H and A led to virtually the same rate of efficient antimicrobial therapy (in 120/131 and 123/131 episodes, respectively, P=0.63). Compared to the gold standard, options H and A did not lead to a significant reduction of carbapenem prescription (9/131, 6/131 and 12/131, P=0.57 and P=0.65, respectively)., Conclusions: Under our test conditions, BLT, when used in conjunction with MALDI-TOF MS and AMST advice, did not allow a significant optimization of the antimicrobial prescription made on the basis AMST advice only. However, the impact of BLT should be evaluated in a population with high prevalence of ESBL-producing Enterobacteriaceae and/or when treatment choices are not made by infectious disease specialists.

In most bacteria, the essential targets of β-lactam antibiotics are the d,d-transpeptidases that catalyze the last step of peptidoglycan polymerization by forming 4→3 cross-links. The peptidoglycan of Clostridium difficile is unusual since it mainly contains 3→3 cross-links generated by l,d-transpeptidases. To gain insight into the characteristics of C. difficile peptidoglycan cross-linking enzymes, we purified the three putative C. difficile l,d-transpeptidase paralogues Ldt Cd1 , Ldt Cd2 , and Ldt Cd3 , which were previously identified by sequence analysis. The catalytic activities of the three proteins were assayed with a disaccharide-tetrapeptide purified from the C. difficile cell wall. Ldt Cd2 and Ldt Cd3 catalyzed the formation of 3→3 cross-links (l,d-transpeptidase activity), the hydrolysis of the C-terminal d-Ala residue of the disaccharide-tetrapeptide substrate (l,d-carboxypeptidase activity), and the exchange of the C-terminal d-Ala for d-Met. Ldt Cd1 displayed only l,d-carboxypeptidase activity. Mass spectrometry analyses indicated that Ldt Cd1 and Ldt Cd2 were acylated by β-lactams belonging to the carbapenem (imipenem, meropenem, and ertapenem), cephalosporin (ceftriaxone), and penicillin (ampicillin) classes. Acylation of Ldt Cd3 by these β-lactams was not detected. The acylation efficacy of Ldt Cd1 and Ldt Cd2 was higher for the carbapenems (480 to 6,600 M -1 s -1 ) than for ampicillin and ceftriaxone (3.9 to 82 M -1 s -1 ). In contrast, the efficacy of the hydrolysis of β-lactams by Ldt Cd1 and Ldt Cd2 was higher for ampicillin and ceftriaxone than for imipenem. These observations indicate that Ldt Cd1 and Ldt Cd2 are inactivated only by β-lactams of the carbapenem class due to a combination of rapid acylation and the stability of the resulting covalent adducts., (Copyright © 2017 American Society for Microbiology.)

Objective: The management of infective endocarditis (IE) may differ from international guidelines, even in reference centres. This is probably because most recommendations are not based on hard evidence, so the consensus obtained for the guidelines does not represent actual practices. For this reason, we aimed to evaluate this question in the particular field of antibiotic therapy., Methods: Thirteen international centres specialized in the management of IE were selected, according to their reputation, clinical results, original research publications and quotations. They were asked to detail their actual practice in terms of IE antibiotic treatment in various bacteriological and clinical situations. They were also asked to declare their IE-related in-hospital mortality for the year 2015., Results: The global compliance with guidelines concerning antibiotic therapy was 58%, revealing the differences between theoretical 'consensus', local recommendations and actual practice. Some conflicts of interest were also probably expressed. The adherence to guidelines was 100% when the protocol was simple, and decreased with the seriousness of the situation (Staphylococus spp. 54%-62%) or in blood-culture-negative endocarditis (0%-15%) that requires adaptation to clinical and epidemiological data., Conclusion: Worldwide experts in IE management, although the majority of them were involved and co-signed the guidelines, do not follow international consensus guidelines on the particular point of the use of antibiotics., (Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Objectives: The aim of this study was to present a 15-year experience and provide a comprehensive analysis of a large cohort of patients with Pseudomonas aeruginosa osteomyelitis., Methods: We reviewed the medical records of patients admitted to a large French university hospital for P. aeruginosa osteomyelitis over a 15-year period. Patient outcome was assessed at follow-up after at least six months., Results: Sixty-seven patients were included, comprising 57% with chronic osteomyelitis. Polymicrobial infection was predominant (63%), and an infected device was involved in 39% patients. The overall treatment success rate was 79.1%. All but one patient were treated with a combination of surgery and antibiotic therapy. The antibiotic treatment had a mean duration of 45 days (range, 21-90 days). Single-antibiotic therapy was preferred in nearly all cases. Treatment failure was reported for 14 (21%) patients and was due to the persistence of P. aeruginosa in four cases. No significant risk factor for treatment failure was identified, especially when treatment strategies were compared., Conclusions: We advocate optimal surgical debridement combined with initial parenteral antibiotics for a maximum of 15 days, followed by an oral fluoroquinolone. Total treatment duration should not exceed six weeks, and antibiotic treatment with two-drug combinations does not seem necessary., (Copyright © 2017 The British Infection Association. Published by Elsevier Ltd. All rights reserved.)

Objective: Infections are the major cause of morbidity and mortality in immunocompromised patients. Improving microbiological diagnosis in these patients is of paramount clinical importance., Methods: We performed this multicentre, blinded, prospective, proof-of-concept study, to compare untargeted next-generation sequencing with conventional microbiological methods for first-line diagnosis of infection in 101 immunocompromised adults. Patients were followed for 30 days and their blood samples, and in some cases nasopharyngeal swabs and/or biological fluids, were analysed. At the end of the study, expert clinicians evaluated the results of both methods. The primary outcome measure was the detection rate of clinically relevant viruses and bacteria at inclusion., Results: Clinically relevant viruses and bacteria identified by untargeted next-generation sequencing and conventional methods were concordant for 72 of 101 patients in samples taken at inclusion (κ test=0.2, 95% CI 0.03-0.48). However, clinically relevant viruses and bacteria were detected in a significantly higher proportion of patients with untargeted next-generation sequencing than conventional methods at inclusion (36/101 (36%) vs. 11/101 (11%), respectively, p <0.001), and even when the latter were continued over 30 days (19/101 (19%), p 0.003). Untargeted next-generation sequencing had a high negative predictive value compared with conventional methods (64/65, 95% CI 0.95-1)., Conclusions: Untargeted next-generation sequencing has a high negative predictive value and detects more clinically relevant viruses and bacteria than conventional microbiological methods. Untargeted next-generation sequencing is therefore a promising method for microbiological diagnosis in immunocompromised adults., (Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Background: Rapid diagnostic tests detecting microbial resistance are needed for limiting the duration of inappropriateness of empirical antimicrobial therapy (EAT) in intensive care unit patients, besides reducing the use of broad-spectrum antibiotics. We hypothesized that the betaLACTA® test (BLT) could lead to early increase in the adequacy of antimicrobial therapy., Methods: This was a case-control study. Sixty-one patients with BLT-guided adaptation of EAT were prospectively included, and then matched with 61 "controls" having similar infection characteristics (community or hospital-acquired, and source of infection), in whom EAT was conventionally adapted to antibiogram results. Endpoints were to compare the proportion of appropriate (primary endpoint) and optimal (secondary endpoint) antimicrobial therapies with each of the two strategies, once microbiological sample culture results were available., Results: Characteristics of patients, infections and EAT at inclusion were similar between groups. Nine early escalations of EAT occurred in the BLT-guided adaptation group, reaching 98% appropriateness vs. 77% in the conventional adaptation group (p < 0.01). The BLT reduced the time until escalation of an inappropriate EAT from 50.5 (48-73) to 27 (24-28) hours (p < 0.01). Seventeen early de-escalations occurred in the BLT-guided adaptation group, compared to one in the conventional adaptation group, reducing patients' exposure to broad-spectrum beta-lactam such as carbapenems. In multivariate analysis, use of the BLT was strongly associated with early appropriate (OR = 18 (3.4-333.8), p = 0.006) and optimal (OR = 35.5 (9.6-231.9), p < 0.001) antimicrobial therapies. Safety parameters were similar between groups., Conclusions: Our study suggests that a BLT-guided adaptation strategy may allow early beta-lactam adaptation from the first 24 hours following the beginning of sepsis management.

Objectives: Mycobacterium tuberculosis and Mycobacterium abscessus produce broad-spectrum class A β-lactamases, BlaC and Bla Mab , which are inhibited by clavulanate and avibactam, respectively. BlaC differs from Bla Mab at Ambler position 132 in the conserved motif SDN (SDG versus SDN, respectively). Here, we investigated whether this polymorphism could account for the inhibition specificity of β-lactamases from slowly and rapidly growing mycobacteria., Methods: Enzyme kinetics were determined to assess the impact of the substitutions G 132 N in BlaC and N 132 G in Bla Mab on β-lactamase inhibition by clavulanate and avibactam. The stability of acylenzymes was evaluated by MS. The impact of the substitutions on the antibacterial activity of drug combinations was determined based on production of the β-lactamases in Escherichia coli ., Results: The substitution G 132 N increased 140-fold the efficacy of BlaC inhibition by avibactam and abolished clavulanate inhibition due to acylenzyme hydrolysis. Bla Mab efficiently hydrolysed clavulanate, but the substitution N 132 G led to a 5600-fold reduction in the hydrolysis rate constant k cat due to stabilization of Bla Mab -clavulanate covalent adducts. The N 132 G substitution also led to a 610-fold reduction in the efficacy of Bla Mab carbamylation by avibactam. Testing resistance to the amoxicillin/clavulanate and amoxicillin/avibactam combinations revealed that modifications in the catalytic properties of the β-lactamases resulted in opposite shifts from susceptibility to resistance and vice versa., Conclusions: G 132 N and N 132 G had opposite effects on the inhibition of BlaC and Bla Mab , indicating that these substitutions might lead to acquisition of resistance to either of the β-lactamase inhibitors, but not to both of them., (© The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Ceftolozane-tazobactam was tested against 58 multidrug-resistant nonfermenting Gram-negative bacilli (35 Pseudomonas aeruginosa , 11 Achromobacter xylosoxydans , and 12 Stenotrophomonas maltophilia isolates) isolated from cystic fibrosis patients and was compared to ceftolozane alone, ceftazidime, meropenem, and piperacillin-tazobactam. Ceftolozane-tazobactam was the most active agent against P. aeruginosa but was inactive against A. xylosoxydans and S. maltophilia In time-kill experiments, ceftolozane-tazobactam had complete bactericidal activity against 2/6 clinical isolates (33%)., (Copyright © 2017 American Society for Microbiology.)

Mycobacterium abscessus pulmonary infections are treated with a macrolide (clarithromycin or azithromycin), an aminoglycoside (amikacin), and a β-lactam (cefoxitin or imipenem). The triple combination is used without any β-lactamase inhibitor, even though M abscessus produces the broad-spectrum β-lactamase Bla Mab We determine whether inhibition of Bla Mab by avibactam improves the activity of imipenem against M. abscessus The bactericidal activity of drug combinations was assayed in broth and in human macrophages. The in vivo efficacy of the drugs was tested by monitoring the survival of infected zebrafish embryos. The level of Bla Mab production in broth and in macrophages was compared by quantitative reverse transcription-PCR and Western blotting. The triple combination of imipenem (8 or 32 μg/ml), amikacin (32 μg/ml), and avibactam (4 μg/ml) was bactericidal in broth (<0.1% survival), with 3.2- and 4.3-log 10 reductions in the number of CFU being achieved at 72 h when imipenem was used at 8 and 32 μg/ml, respectively. The triple combination achieved significant intracellular killing, with the bacterial survival rates being 54% and 7% with the low (8 μg/ml) and high (32 μg/ml) dosages of imipenem, respectively. In vivo inhibition of Bla Mab by avibactam improved the survival of zebrafish embryos treated with imipenem. Expression of the gene encoding Bla Mab was induced (20-fold) in the infected macrophages. Inhibition of Bla Mab by avibactam improved the efficacy of imipenem against M. abscessus in vitro , in macrophages, and in zebrafish embryos, indicating that this β-lactamase inhibitor should be clinically evaluated. The in vitro evaluation of imipenem may underestimate the impact of Bla Mab , since the production of the β-lactamase is inducible in macrophages., (Copyright © 2017 American Society for Microbiology.)

Isolated epidural abscesses are uncommon lesions. Surgical treatment may be difficult due to the extension of these lesions. We present a case of a pelvic abscess spreading along the path of the sciatic nerve to the gluteus muscles and the lumbar canal, causing neurological compression; requiring surgical treatment with three simultaneous approaches., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)