In Vivo Emergence of Dual Resistance to Rifampin and Levofloxacin in Osteoarticular Cutibacterium avidum.

Cutibacterium avidum is an emerging causative agent of orthopedic device-related infections (ODRIs). There are no guidelines for the antimicrobial treatment of C. avidum ODRI, but oral rifampin is frequently used in combination with a fluoroquinolone following intravenous antibiotics. We describe the in vivo emergence of combined resistance to rifampin and levofloxacin in a C. avidum strain isolated from a patient with early-onset ODRI treated with debridement, antibiotic treatment, and implant retention (DAIR) using rifampin combined with levofloxacin as the oral treatment. Whole-genome sequencing of C. avidum isolates before and after antibiotic exposure confirmed strain identity and identified new mutations in rpoB and gyrA, leading to amino acid substitutions previously reported to be associated with resistance to rifampin (S446P) and fluoroquinolones (S101L), respectively, in other microbial agents, in the posttherapy isolate. Aside from the molecular insights reported here, this study highlights potential limitations of the combination of oral rifampin and levofloxacin in patients undergoing a DAIR procedure for C. avidum ODRI and the potential need to evaluate specific optimal therapy for emerging ODRI pathogens. IMPORTANCE In this study, we report for the first time the in vivo emergence of dual resistance to levofloxacin and rifampin in C. avidum isolated from a patient who received both antibiotics orally in the setting of a salvage debridement and implant retention of an ODRI. Aside from the molecular insights reported here, this study highlights potential limitations of the combination of oral rifampin and levofloxacin in patients undergoing these surgical procedures and the potential need to evaluate specific optimal therapy for emerging ODRI pathogens.

Labeled TEMPO-Oxidized Mannan Differentiates Binding Profiles within the Collectin Families.

Establishing the rapid and accurate diagnosis of sepsis is a key component to the improvement of clinical outcomes. The ability of analytical platforms to rapidly detect pathogen-associated molecular patterns (PAMP) in blood could provide a powerful host-independent biomarker of sepsis. A novel concept was investigated based on the idea that a pre-bound and fluorescent ligand could be released from lectins in contact with high-affinity ligands (such as PAMPs). To create fluorescent ligands with precise avidity, the kinetically followed TEMPO oxidation of yeast mannan and carbodiimide coupling were used. The chemical modifications led to decreases in avidity between mannan and human collectins, such as the mannan-binding lectin (MBL) and human surfactant protein D (SP-D), but not in porcine SP-D. Despite this effect, these fluorescent derivatives were captured by human lectins using highly concentrated solutions. The resulting fluorescent beads were exposed to different solutions, and the results showed that displacements occur in contact with higher affinity ligands, proving that two-stage competition processes can occur in collectin carbohydrate recognition mechanisms. Moreover, the fluorescence loss depends on the discrepancy between the respective avidities of the recognized ligand and the fluorescent mannan. Chemically modulated fluorescent ligands associated with a diversity of collectins may lead to the creation of diagnostic tools suitable for multiplex array assays and the identification of high-avidity ligands.

Contamination and carryover free handling of complex fluids using lubricant-infused pipette tips.

Cross-contamination of biological samples during handling and preparation, is a major issue in laboratory setups, leading to false-positives or false-negatives. Sample carryover residue in pipette tips contributes greatly to this issue. Most pipette tips on the market are manufactured with hydrophobic polymers that are able to repel high surface tension liquids, yet they lack in performance when low surface tension liquids and viscous fluids are involved. Moreover, hydrophobicity of pipette tips can result in hydrophobic adsorption of biomolecules, causing inaccuracies and loss in precision during pipetting. Here we propose the use of lubricant-infused surface (LIS) technology to achieve omniphobic properties in pipette tips. Using a versatile and simple design, the inner lumen of commercially available pipette tips was coated with a fluorosilane (FS) layer using chemical vapor deposition (CVD). The presence of FS groups on the tips is confirmed by x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) tests. After lubrication of the tips through a fluorinated lubricant, the omniphobicity and repellent behaviour of the tips drastically enhanced which are revealed via static and hysteresis contact angle measurements. The repellency of the lubricant-infused pipette tips against physical adsorption is investigated through pipetting a food coloring dye as well as human blood samples and are compared to the untreated tips. The results show significantly less amount carryover residue when the lubricant-infused tips are utilized compared to commercially available ones. We also demonstrate the lubricant-infused tips reduce bacteria contamination of the inner lumen by 3 to 6-log (over 99%, depending on the tip size) after pipetting up and down the bacteria solution.

Cutibacterium acnes clonal complexes display various growth rates in blood culture vials used for diagnosing orthopedic device-related infections.

OBJECTIVES: Blood culture bottles (BCBs) are commonly used for the diagnosis of infections associated with orthopedic devices. Although Cutibacterium acnes is an important pathogen in orthopedics, relatively little is known about its growth characteristics in BCBs. This prompted us to analyze the influence of bacterial genotype and clinical significance on time-to-detection (TTD) in BCBs. METHODS: We reviewed 59 cases of orthopedic device-related infections in which at least one intraoperative specimen yielded a pure C. acnes culture from anaerobic BCBs (BD Bactec Lytic/10 Anaerobic/F; Lytic-Ana) and/or solid media. A strain was considered infectant if the same genotype was present in two or more intraoperative samples. From these cases, we isolated a total of 72 unique C. acnes strains belonging to four multilocus sequence type clonal complexes (CCs): CC18, CC28, CC36 and CC53. Growth rate and TTD in Lytic-Ana BCB were studied under experimental conditions (inoculation of standard inoculum) and in clinical samples (inoculation of periprosthetic tissue samples). RESULTS: Median TTD values were shorter for CC53 compared to other CCs under experimental conditions (69 vs. 103 h; p < 0.001) and from clinical specimens (70 vs. 200 h; p = 0.02). Infectant strains had a shorter median TTD compared to contaminant strains in a clinical situation, while the difference was not observed under experimental conditions. CONCLUSIONS: The detection dynamics of C. acnes in Lytic-Ana BCBs were associated with genotype. Thus, TTD not only reflects the bacterial load in clinical samples, but may also reflect the intrinsic properties of the clonal complex of C. acnes.

Randomized Cross Over Study Assessing the Efficacy of Non-invasive Stimulation of the Vagus Nerve in Patients With Axial Spondyloarthritis Resistant to Biotherapies: The ESNV-SPA Study Protocol.

Axial spondyloarthritis (SpA), is a major cause of chronic pain and disability that profoundly alters the quality of life of patients. Nearly half of patients with SpA usually develop drug resistance. Non-pharmacological treatments targeting inflammation are an attractive alternative to drug administration. Vagus nerve stimulation (VNS), by promoting a cholinergic anti-inflammatory reflex holds promise for treating inflammatory disease. Inflammatory reflex signaling, which is enhanced by electrically stimulating the vagus nerve, significantly reduces cytokine production and attenuates disease severity in animal models of endotoxemia, sepsis, colitis, and other preclinical models of inflammatory diseases. It has been proposed that vagal efferent fibers release acetylcholine (Ach), which can interact with α7-subunit-containing nicotinic receptors expressed by tissue macrophages and other immune cells to rapidly inhibit the synthesis/release of pro-inflammatory cytokines such as TNFα, IL-1ß, IL-6, and IL-18. External vagal nerve stimulation devices are now available that do not require surgery nor implantation to non-invasively stimulate the vagal nerve. This double-blind randomized cross-over clinical trial aims to study the change in SpA disease activity, according to Assessment in Ankylosing Spondylitis 20 (ASAS20) definition, after 12 weeks of non-invasive VNS treatment vs. non-specific dummy stimulation (control group). One hundred and twenty adult patients with drug resistant SpA, meeting the ASAS classification criteria, will be included in the study. Patients will be randomized into two parallel groups according to a cross over design: either active VNS for 12 weeks, then dummy stimulation for 12 weeks, or dummy stimulation for 12 weeks, then active VNS for 12 weeks. The two stimulation periods will be separated by a 4 weeks wash-out period. A transcutaneous auricular vagus nerve stimulator Tens Eco Plus SCHWA MEDICOTM France will be used in this study. The active VNS stimulation will be applied in the cymba conchae of the left ear upon the auricular branch of the vagus nerve, using low intensity (2-5 mA), once à week, during 1 h. Dummy stimulation will be performed under the same conditions and parameters as active VNS stimulation, but at an irrelevant anatomical site: the left ear lobule. This multicenter study was registered on ClinicalTrials.gov: NCT04286373.

Treatment of bone and joint infections by ceftazidime/avibactam and ceftolozane/tazobactam: a cohort study.

OBJECTIVES: Ceftazidime/avibactam (C/A) and ceftolozane/tazobactam (C/T) are two novel antibacterials with known efficacy against Gram-negative bacteria (GNB). We aimed to describe the efficacy and safety of surgical management combined with C/A or C/T treatment for bone and joint infections (BJIs). METHODS: We conducted an observational, bicentric study of patients treated with C/A or C/T for a BJI between May 2016 and June 2019. Failure was defined as the need for unplanned additional antibiotic treatment or orthopaedic surgery, or death due to the BJI up to the patient's latest visit. RESULTS: Overall, 15 patients were included. Nine patients were treated with C/A, mainly for polymicrobial BJI due to multidrug-resistant (MDR) bacteria (Enterobacteriaceae, n = 7). Six patients were male, the median age was 66 years and the median Charlson comorbidity index (CCI) was 5. It was the first septic episode at the site in 3/9 patients. The cure rate was 7/9 (median follow-up, 272 days). Two patients showed C/A-related confusion. Five patients were treated with C/T for BJI involving MDR Pseudomonas aeruginosa. Four patients were male, the median age was 53 years and the median CCI was 2. All patients had previous septic episodes at the infection site. The cure rate was 3/5 (median follow-up, 350 days). One patient was successfully treated by C/T then C/A for multistage spondylodiscitis. CONCLUSION: In our experience, C/A and C/T are two effective and safe options, even as salvage treatment for BJI due to MDR-GNB despite the absence of label, however more data are warranted.

Four-Hour Immunochromatographic Detection of Intestinal Carriage of Carbapenemase-Producing Enterobacteriaceae: a Validation Study.

The increasing incidence of carbapenemase-producing Gram-negative bacilli (C-PGNB) represents a major public health challenge. Rapid detection of digestive colonization with C-PGNB is fundamental to control their spread. We performed the validation of a rapid protocol for C-PGNB detection directly on rectal swabs. We developed a protocol combining enrichment by a rapid selective subculture of the rectal swab medium and realization of a Resist-4 O.K.N.V. K-SeT test on the bacterial pellet obtained. The limit of detection and performances of this protocol were validated in vitro on 52 C-PGNB strains spiked on a calibrated sample suspension and confirmed in clinical settings on 144 rectal swabs sampled from patients with C-PGNB digestive colonization (n = 48) and controls (patients with extended-spectrum beta-lactamase [ESBL] colonization [n = 48] and without carbapenemase/ESBL [n = 48]). The protocol detected, with 100% sensitivity, the presence of the 15 OXA-48-, 14 KPC-, 13 NDM-, and 10 VIM-producing GNB from 103 CFU/ml. The limit of detection was 2 × 102 CFU/ml. Among the 48 C-PGNB-containing rectal swabs of the validation cohort, 46 were accurately detected. False negative were observed for 1 NDM-producing Acinetobacter baumannii strain and 1 OXA-48-producing Escherichia coli strain. The 96 control swabs were negative. Sensitivity and specificity for C-PGNB detection were 97.7% (95% confidence interval [CI], 87.7 to 100) and 100% (95% CI, 96.2 to 100). The negative likelihood ratio was 0.04 (95% CI, 0.01 to 0.16). Considering a C-PGNB digestive colonization prevalence between 0.01% and 0.1%, positive and negative predictive values were 100%. Our protocol is a rapid and low-cost method detecting accurately the digestive colonization with carbapenemase-producing Enterobacteriaceae in 4 h without any requirement for specific equipment.

Versatile and flexible microfluidic qPCR test for high-throughput SARS-CoV-2 and cellular response detection in nasopharyngeal swab samples.

The emergence and quick spread of SARS-CoV-2 has pointed at a low capacity response for testing large populations in many countries, in line of material, technical and staff limitations. The traditional RT-qPCR diagnostic test remains the reference method and is by far the most widely used test. These assays are limited to a few probe sets, require large sample PCR reaction volumes, along with an expensive and time-consuming RNA extraction step. Here we describe a quantitative nanofluidic assay that overcomes some of these shortcomings, based on the BiomarkTM instrument from Fluidigm. This system offers the possibility of performing 4608 qPCR end-points in a single run, equivalent to 192 clinical samples combined with 12 pairs of primers/probe sets in duplicate, thus allowing the monitoring of SARS-CoV-2 including the detection of specific SARS-CoV-2 variants, as well as the detection other pathogens and/or host cellular responses (virus receptors, response markers, microRNAs). The 10 nL-range volume of BiomarkTM reactions is compatible with sensitive and reproducible reactions that can be easily and cost-effectively adapted to various RT-qPCR configurations and sets of primers/probe. Finally, we also evaluated the use of inactivating lysis buffers composed of various detergents in the presence or absence of proteinase K to assess the compatibility of these buffers with a direct reverse transcription enzymatic step and we propose several protocols, bypassing the need for RNA purification. We advocate that the combined utilization of an optimized processing buffer and a high-throughput real-time PCR device would contribute to improve the turn-around-time to deliver the test results to patients and increase the SARS-CoV-2 testing capacities.

A mobile DNA laboratory for forensic science adapted to coronavirus SARS-CoV-2 diagnosis.

The Forensic Science Institute of the French "Gendarmerie Nationale" (IRCGN™) developed in 2015 an ISO 17025 certified mobile DNA laboratory for genetic analyses. This Mobil'DNA laboratory is a fully autonomous and adaptable mobile laboratory to perform genetic analyses in the context of crime scenes, terrorism attacks or disasters. To support the hospital task force in Paris during the peak of the COVID-19 epidemic, we adapted this mobile genetic laboratory to perform high-throughput molecular screening for coronavirus SARS-CoV-2 by real-time PCR. We describe the adaptation of this Mobil'DNA lab to assist in Coronavirus SARS-CoV-2 diagnosis.

Fluorescein Derivatives as Fluorescent Probes for pH Monitoring along Recent Biological Applications.

Potential of hydrogen (pH) is one of the most relevant parameters characterizing aqueous solutions. In biology, pH is intrinsically linked to cellular life since all metabolic pathways are implicated into ionic flows. In that way, determination of local pH offers a unique and major opportunity to increase our understanding of biological systems. Whereas the most common technique to obtain these data in analytical chemistry is to directly measure potential between two electrodes, in biological systems, this information has to be recovered in-situ without any physical interaction. Based on their non-invasive optical properties, fluorescent pH-sensitive probe are pertinent tools to develop. One of the most notorious pH-sensitive probes is fluorescein. In addition to excellent photophysical properties, this fluorophore presents a pH-sensitivity around neutral and physiologic domains. This review intends to shed new light on the recent use of fluorescein as pH-sensitive probes for biological applications, including targeted probes for specific imaging, flexible monitoring of bacterial growth, and biomedical applications.

Eculizumab as an emergency treatment for adult patients with severe COVID-19 in the intensive care unit: A proof-of-concept study.

BACKGROUND: Complement pathway inhibition may provide benefit for severe acute respiratory illnesses caused by viral infections such as COVID-19. We present results from a nonrandomized proof-of-concept study of complement C5 inhibitor eculizumab for treatment of severe COVID-19. METHODS: All patients (N = 80) with confirmed SARS-CoV-2 infection and severe COVID-19 admitted to our intensive care unit between March 10 and May 5, 2020 were included. Forty-five patients were treated with standard care and 35 with standard care plus eculizumab through expanded-access emergency treatment. The prespecified primary outcome was day-15 survival. Clinical laboratory values and biomarkers, complement levels, and treatment-emergent serious adverse events (TESAEs) were also assessed. FINDINGS: At day 15, estimated survival was 82.9% (95% CI: 70.4%‒95.3%) with eculizumab and 62.2% (48.1%‒76.4%) without eculizumab (log-rank test, P = 0.04). Patients treated with eculizumab experienced a significantly more rapid decrease in lactate, blood urea nitrogen, total and conjugated bilirubin levels and a significantly more rapid increase in platelet count, prothrombin time, and in the ratio of arterial oxygen tension over fraction of inspired oxygen versus patients treated without eculizumab. Eculizumab-associated changes in complement levels, laboratory values, and biomarkers were consistent with terminal complement inhibition, reduced hypoxia, and decreased inflammation. TESAEs of special interest occurring in >5% of patients treated with/without eculizumab were ventilator-associated pneumonia (51%/24%), bacteremia (11%/2%), gastroduodenal hemorrhage (14%/16%), and hemolysis (3%/18%). INTERPRETATION: Findings from this proof-of-concept study suggest eculizumab may improve survival and reduce hypoxia in patients with severe COVID-19. Randomized studies evaluating the efficacy and safety of this treatment approach are needed. FUNDING: Programme d'Investissements d'Avenir: ANR-18-RHUS60004.

Predictive factors for positive disco-vertebral biopsy culture in pyogenic vertebral osteomyelitis, and impact of fluoroscopic versus scanographic guidance.

BACKGROUND: The aims of this study were to identify the predictive factors for microbiological diagnosis through disco-vertebral biopsy (DVB) in patients with pyogenic vertebral osteomyelitis (PVO) and negative blood cultures, and compare the performance of DVB under fluoroscopic versus scanographic guidance. METHODS: We performed a cohort study comparing positive and negative DVB among patients with PVO. All cases of PVO undergoing a DVB for microbiological diagnosis in our center were retrospectively reviewed. Infections due to Mycobacterium tuberculosis, infections on foreign device, and non-septic diseases were excluded. Anamnestic, clinical, biological, microbiological, as well as radiological data were collected from medical charts thanks to a standardized data set. RESULTS: A total of 111 patients were screened; 88 patients were included. Microbiological cultures were positive in 53/88 (60.2%) patients. A thickening of the paravertebral tissue ≥10 mm on magnetic resonance imaging (MRI) in axial MR scans was a predictive factor of DVB microbiological positivity (52.4% vs. 13.3%; p = 0.006; OR = 5.4). Overall, 51 DVB were performed under fluoroscopic guidance and 37 under scanographic guidance. Considering lumbar DVB, 25/36 (69.4%) of cases yielded positive results under fluoroscopic guidance versus 5/15 (33.3%) under scanographic guidance (p = 0.02; OR = 4.4). No adverse event linked to DVB was notified. CONCLUSION: Every patient with PVO and negative blood cultures should undergo a DVB. A thickening of the paravertebral tissue ≥10 mm on MRI is associated with a higher rate of positive DVB culture. A lumbar DVB under fluoroscopic guidance is more sensitive than under scanographic guidance to identify the micro-organism involved.

Measurement of Serum Anti-staphylococcal Antibodies Increases Positive Predictive Value of Preoperative Aspiration for Hip Prosthetic Joint Infection.

BACKGROUND: Preoperative synovial fluid culture is pivotal in the early diagnosis of prosthetic joint infection (PJI) but may yield false-positive and false-negative results. We evaluated the predictive value of synovial fluid culture results combined with the measurement of serum anti-staphylococcal antibodies (SASA). QUESTIONS/PURPOSES: (1) For hip and knee PJI, does combining positive SASA results with preoperative synovial culture results improve the positive predictive value (PPV) of preoperative synovial fluid culture alone? (2) Does combining preoperative synovial fluid culture results with a positive cell count and differential result increase the PPV of preoperative synovial fluid culture alone? (3) What proportion of isolated organisms exhibit concordance in antibiotic susceptibility: preoperative aspiration versus intraoperative isolates? METHODS: A prospective study was conducted at two French reference centers that manage bone and joint infections and included 481 adult patients who had a revision or resection arthroplasty between June 25, 2012 and June 23, 2014. Exclusion criteria including no serum sample available for immunoassay, the lack of microbiological documentation, and the absence of preoperative aspiration reduced the patient number to 353. Seven patients with an undetermined SASA result were excluded from the analysis. We also excluded patients with PJI involving more than one Staphylococcus species (polystaphylococcal infection) and those in whom more than one Staphylococcus species was recovered from the preoperative synovial fluid culture (polystaphylococcal synovial fluid culture). In total, 340 patients were included in the analysis (no infection, 67% [226 of 340]; staphylococcal infection, 21% [71 of 340]; other infection, 13% [43 of 340]). The preoperative synovial fluid analysis included a cell count and differential and bacterial culture. SASAs were measured using a multiplex immunoassay. The diagnosis of PJI was determined using the Infectious Diseases Society of America (IDSA) criteria [] and intraoperative tissue culture at the time of revision surgery was used as the gold standard (at least one positive intraoperative sample for a "virulent" organism (such as S. aureus) or two positive samples for a "non-virulent" (for example S. epidermidis). RESULTS: SASA increased the PPV compared with synovial fluid culture alone (92% [95% CI 82 to 97] versus 79% [95% CI 68 to 87]; p = 0.04); when stratified by site, an increase in PPV was seen in hip infections (100% [95% CI 89 to 100] versus 77% [95% CI 63 to 88]; p = 0.01) but not in knee infections (84% [95% CI 66 to 95] versus 80% [95% CI 64 to 91]; p = 0.75). A positive cell count and differential result increased the PPV of staphylococcal synovial fluid cultures compared with synovial fluid culture alone (86% [95% CI 70 to 95] versus 79% [95% CI 68 to 87]; p = 0.36); when stratified by site, no difference in hip and knee infections was observed (86% [95% CI 67 to 96] versus 77% [95% CI 63 to 88]; p = 0.42) and 86% [95% CI 70 to 95] versus 80% [95% CI 64 to 91]; p = 0.74). CONCLUSION: SASA measurement improves the predictive value of synovial fluid cultures of the hip for all staphylococcal organisms, including coagulase-negative staphylococci, but the PPV of SASA plus synovial fluid culture it is not superior to the PPV of synovial fluid cell count/differential plus synovial culture for the knee. LEVEL OF EVIDENCE: Level III, diagnostic study.

Plasma Biomarkers Screening by Multiplex ELISA Assay in Patients with Advanced Non-Small Cell Lung Cancer Treated with Immune Checkpoint Inhibitors.

Immune checkpoint inhibitors (ICIs) are commonly used in patients with advanced non-small cell lung cancer (NSCLC). An unmet need remains for new biomarkers associated with ICIs. In this study, consecutive patients with advanced NSCLC treated with nivolumab or pembrolizumab were included. Plasma at ICIs initiation was prospectively collected and a multiplex ELISA assay testing 48 cytokines and growth factors was performed. Exploratory endpoints were the association between plasma biomarkers with outcome and grade III-IV immune related adverse events (irAEs). Thirty-five patients were included. Patients without clinical benefit (n = 22) had higher pre-ICI soluble Hepatocyte Growth Factor (sHGF) (210.9 vs. 155.8 pg/mL, p = 0.010), lower pre-ICI soluble Fibroblast Growth Factor (sFGF) (4.0 vs. 4.8 pg/mL, p = 0.043) and lower pre-ICI interleukine-12 (IL-12) (1.3 vs. 2.2 pg/mL, p = 0.043) concentrations. Patients with early progression (n = 23) had higher pre-ICIs sHGF (206.2 vs. 155.8 pg/mL, p = 0.025) concentrations. Patients with low sHGF levels at ICIs initiation had longer progression-free survival and overall survival than those with high sHGF levels: respectively 2.5 vs. 8.0 months (p = 0.002), and 5.5 vs. 35.0 months (p = 0.001). TNF-α, IL-16, IL-12p40 and MCP3 were associated with high grade irAEs. This study shows the potential association between several plasma biomarkers with outcome and grade 3-4 IrAEs in advanced NSCLC treated with ICIs.

Growth detection of Cutibacterium acnes from orthopaedic implant-associated infections in anaerobic bottles from BACTEC and BacT/ALERT blood culture systems and comparison with conventional culture media.

Cutibacterium acnes is a major etiologic agent of orthopaedic implant-associated infections (IAIs) and requires up to 14 days of incubation in an anaerobic atmosphere for growth detection. As blood culture (BC) systems are increasingly being used to monitor the growth of IAI specimens, we compared different BC media for growth detection of C. acnes. Non-duplicate C. acnes isolates (n = 99) obtained from sonicate-fluid cultures of orthopaedic IAIs from Slovenia (n = 54), conventional tissue samples of monomicrobial orthopaedic IAIs from France (n = 43) and two reference strains were inoculated to anaerobic BC bottles of two major BC systems and 3 conventional culture media types (thioglycolate broth, Schaedler and chocolate agar). Growth and time-to-detection (TTD) were recorded. Only Lytic (BACTEC) and SN (BacT/ALERT) bottles consistently detected growth of C. acnes within 14 days with 94% (n = 93) and 92% (n = 91) detection rates, respectively (p = 0.79). Lytic was superior to Plus BACTEC medium (p < 0.001), while SN was superior to all other BacT/ALERT media (p < 0.001). Mean TTD was 128 ± 43 h (61-336 h) for Lytic and 158 ± 65 h (77-336 h) for SN medium. Among the conventional media, 99% (n = 98) of the isolates grew on Schaedler agar, 96% (n = 95) in thioglycolate broth and 74% (n = 73) on chocolate agar. Inconsistent growth of C. acnes in different BC media can critically influence the detection of this major IAI pathogen. Only Lytic (BACTEC) and SN (BacT/ALERT) BC media types were consistently able to detect C. acnes within 14 days of incubation. However, visible growth was observed faster in thioglycolate broth and Schaedler agar media.

Multiplex Antibody Measurement for Post-treatment Follow-up of Staphylococcal Prosthetic Joint Infection: A Diagnostic Pilot Study.

Introduction: Multiplex-antibody detection has been recently proposed for the noninvasive diagnosis of staphylococcal prosthetic joint infection (PJI). We evaluated this approach for the post-treatment follow-up of patients. Methods: Nineteen cases of staphylococcal PJI were prospectively followed for one year after treatment. The IgG response against eight staphylococcal antigens was measured before surgery and one year post-surgery using Luminex technology (Austin, TX, USA); median fluorescence intensity values determined for each antigen were transformed into a "Total Response Index" (TRI). Results: Patients (11 women/8 men) had a mean (SD) age of 72.2 (12.4) years. Site of prosthesis was the knee (n=10), the hip (n=8) and the shoulder (n=1). Ten patients were infected by S. epidermidis, six by S. aureus, and three by S. lugdunensis. TRI values at one year were significantly lower than pre-surgery values (mean [SD]: 5.9 [1.8] versus 8.1 [3.4], p=0.02) and decreased, on average, by 21.2%. TRI values markedly increased in two patients. One patient had a relapse of S. aureus PJI at five months post-surgery, with a 37% increase of the TRI. The other had septic failure three months after revision for S. lugdunensis PJI; all intraoperative samples remained culture-negative, but the TRI increased by 51% and the antibody profile showed a marked change, suggesting a reinfection with another staphylococcal species. Conclusion: Multiplex-antibody measurement may be useful for the follow-up of staphylococcal PJI and may help to detect septic failure involving organisms targeted by the assay.

Efficacy of cotrimoxazole (Sulfamethoxazole-Trimethoprim) as a salvage therapy for the treatment of bone and joint infections (BJIs).

INTRODUCTION: Cotrimoxazole (Sulfamethoxazole-Trimethoprim, SXT) has interesting characteristics for the treatment of bone and joint infection (BJI): a broad spectrum of activity with adequate bone diffusion and oral and intravenous formulations. However, its efficacy and safety in BJIs are poorly documented and its use remains limited. METHODS: We conducted a retrospective study in 2 reference centers for BJIs from 2013 to 2018 among patients treated with SXT for a BJI. Data were collected from patient's medical charts. Outcomes and adverse events were evaluated at day (D)7, D45 and D90. RESULTS: We analyzed 51 patients with a mean age of 60 ± 20 (SD) years of which 76% presented with an orthopedic device infection (ODI). Gram-negative bacilli (GNB) were involved in 47% of BJIs (n = 24). Moreover, they were often polymicrobial infections (41%). Doses of SXT ranged from 800/160mg bid (61%; n = 31) to 800/160mg tid (39%; n = 20). Median SXT treatment duration was 45 days (IQR 40-45). SXT was part of a dual therapy in 84% of patients (n = 43), associated mainly with fluoroquinolones (n = 17) or rifampicin (n = 14). Outcome was favorable at D7 in 98% (n = 50), at D45 in 88.2% (n = 45) and at D90 in 78.4% (n = 40). The second agent combined with SXT was not an independent factor of favorable outcome (p = 0.97). Adverse events were reported in 8% (n = 4) of patients, with a median of 21 days (IQR 20-30) from SXT initiation and led to discontinuation (n = 3). CONCLUSION: SXT appears to be effective for treatment of BJIs as a salvage therapy, even in GNB or polymicrobial infection, including ODI. Further data are needed to confirm SXT efficacy as an alternative oral regimen in BJIs.

Risk factors for respiratory tract bacterial colonization in adults with neuromuscular or neurological disorders and chronic tracheostomy.

The aim of this study was to describe the endotracheal respiratory flora in a population of adults suffering from neuromuscular or neurological disorders requiring a long-term tracheostomy and to identify risk factors for colonization. We conducted a prospective and single-center observational study among patients with chronic tracheostomy admitted for planned respiratory assessment between February 2015 and December 2016. Data were collected from patient interview and medical charts with a standardized questionnaire. A tracheal aspiration was performed for each patient. Humidifiers were analysed for bacteriological contamination. Overall 77 tracheal aspirates (TA) were obtained from patients included. Pathogenic bacteria were found in 90% of cases (69/77) with a majority of Pseudomonas aeruginosa (32/77, 41%), Staphylococcus aureus (34/77, 44%) and Serratia marcesens. (22/79, 38%) Amoxicillin + Clavulanic-acid and Cefotaxime were adapted for respectively in only 28% and 35% of the subjects due to the natural resistance of organisms. No pathogenic bacteria were isolated from humidifier samples. Risk factors significantly associated with P. aeruginosa colonization were residence in a medical-care home (p = 0.01, OR = 3.8 [1.1; 15.1]) and the presence of a cuff (p = 0.003, OR = 4.4 [1.1; 20.6]). Significant quantities of pathogenic bacteria are frequently isolated from TA of tracheostomised patients in the absence of infection. The frequent resistance of these pathogens to Amoxicillin + Clavulanic-acid precludes the use of this antibiotic in the empiric treatment of pneumonia in this population.

Molecular Typing of Multiple Isolates Is Essential to Diagnose Cutibacterium acnes Orthopedic Device-related Infection.

Cutibacterium acnes orthopedic device-related infections (ODRIs) range from obvious infections to solely culture-based diagnoses. Multilocus sequence typing of multiple isolates from the same procedure revealed that most cases with normal C-reactive protein levels that were classified as C. acnes ODRI would be considered contaminations when accounting for genotypic data.