Facteurs de risque d'échec du traitement dans les infections sur prothèse articulaire à staphylococcus aureus

LYON1-BU Santé (693882101) / SudocSudocFranceF

Rapid detection of Staphylococcus aureus and methicillin resistance in bone and joint infection samples: evaluation of the GeneXpert MRSA/SA SSTI assay

The GeneXpert MRSA/SA SSTI assay was compared to conventional cultures to detect Staphylococcus aureus and methicillin-resistance from 91 bone and joint infection samples. Sensitivity and specificity were 94.4% and 100%. Three false-positive results were observed, in fact providing from patients known to be infected by S. aureus on the basis of other concomitant osteoarticular samples, which suggests that PCR was more sensitive than culture. This diagnosis accuracy may help shorten toxic and non-optimal empirical therapies such as glycopeptides in case of methicillin-susceptible strains

Antimicrobial-Related Severe Adverse Events during Treatment of Bone and Joint Infection Due to Methicillin-Susceptible Staphylococcus aureus

Prolonged antimicrobial therapy is recommended for methicillin-susceptible Staphylococcus aureus (MSSA) bone and joint infections (BJI), but its safety profile and risk factors for severe adverse events (SAE) in clinical practice are unknown. We addressed these issues in a retrospective cohort study (2001 to 2011) analyzing antimicrobial-related SAE (defined according to the Common Terminology Criteria for Adverse Events) in 200 patients (male, 62%; median age, 60.8 years [interquartile range {IQR}, 45.5 to 74.2 years]) with MSSA BJI admitted to a reference regional center with acute (66%) or chronic arthritis (7.5%), osteomyelitis (9.5%), spondylodiscitis (16%), or orthopedic device-related infections (67%). These patients received antistaphylococcal therapy for a median of 26.6 weeks (IQR, 16.8 to 37.8 weeks). Thirty-eight SAE occurred in 30 patients (15%), with a median time delay of 34 days (IQR, 14.75 to 60.5 days), including 10 patients with hematologic reactions, 9 with cutaneomucosal reactions, 6 with acute renal injuries, 4 with hypokalemia, and 4 with cholestatic hepatitis. The most frequently implicated antimicrobials were antistaphylococcal penicillins (ASP) (13 SAE/145 patients), fluoroquinolones (12 SAE/187 patients), glycopeptides (9 SAE/101 patients), and rifampin (7 SAE/107 patients). Kaplan-Meier curves and stepwise binary logistic regression analyses were used to determine the risk factors for the occurrence of antimicrobial-related SAE. Age (odds ratio [OR], 1.479 for 10-year increase; 95% confidence interval [CI], 1.116 to 1.960; P = 0.006) appeared to be the only independent risk factor for SAE. In patients receiving ASP or rifampin, daily dose (OR, 1.028; 95% CI, 1.006 to 1.051; P = 0.014) and obesity (OR, 8.991; 95% CI, 1.453 to 55.627; P = 0.018) were associated with the occurrence of SAE. The high rate of SAE and their determinants highlighted the importance of the management and follow-up of BJI, with particular attention to be paid to older persons, especially for ASP dosage, and to rifampin dose adjustment in obese patients

Water-soluble polysaccharides and hemicelluloses from almond gum: Functional and prebiotic properties

International audienceThis paper describes the extraction of polysaccharides (AGP) and hemicelluloses (AGH) from almond gum by hot water and alkaline solution, respectively. Structural and functional properties of the extracted polymers were then determined. For this purpose, infrared spectroscopy was first used to characterize functional groups of both polymers. The molecular weights of AGP and AGH were then determined using high performance size exclusion chromatography, resulting in 5.72×106g/mol and 5.39×106g/mol, respectively. Monosaccharide composition of both polymers was assessed using gas chromatography. The analysis of the functional properties showed that AGP and AGH had high water-holding (11.36g/g and 6.3g/g, respectively) and fat-binding (5.35g/g and 2.7g/g, respectively) capacities, with good emulsion properties. The prebiotic properties of AGP and AGH were then evaluated using in vitro fermentation by Bifidobacterium adolescentis and Lactobacillus acidophilus. Both polymers showed suitability for in vitro fermentation, suggesting thus their prebiotic nature. The obtained results demonstrated the promising potential of AGP and AGH for different applications in food industry

Teicoplanin-based antimicrobial therapy in Staphylococcus aureus bone and joint infection: tolerance, efficacy and experience with subcutaneous administration

Staphylococci represent the first etiologic agents of bone and joint infection (BJI), leading glycopeptides use, especially in case of methicillin-resistance or betalactam intolerance. Teicoplanin may represent an alternative to vancomycin because of its acceptable bone penetration and possible subcutaneous administration

Delta-toxin production deficiency in Staphylococcus aureus: a diagnostic marker of bone and joint infection chronicity linked with osteoblast invasion and biofilm formation

Biofilm formation, intra-osteoblastic persistence, small-colony variants (SCVs) and the dysregulation of agr, the major virulence regulon, are possibly involved in staphylococcal bone and joint infection (BJI) pathogenesis. We aimed to investigate the contributions of these mechanisms among a collection of 95 Staphylococcus aureus clinical isolates from 64 acute (67.4%) and 31 chronic (32.6%) first episodes of BJI. The included isolates were compared for internalization rate, cell damage and SCV intracellular emergence using an ex vivo model of human osteoblast infection. Biofilm formation was assessed in a microbead immobilization assay (BioFilm Ring test). Virulence gene profiles were assessed by DNA microarray. Seventeen different clonal complexes were identified among the screened collection. The staphylococcal internalization rate in osteoblasts was significantly higher for chronic than acute BJI isolates, regardless of the genetic background. Conversely, no differences regarding cytotoxicity, SCV emergence, biofilm formation and virulence gene distribution were observed. Additionally, agr dysfunction, detected by the lack of delta-toxin production using whole-cell matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) analysis (n = 15; 15.8%), was significantly associated with BJI chronicity, osteoblast invasion and biofilm formation. These findings provide new insights into MSSA BJI pathogenesis, suggesting the correlation between chronicity and staphylococcal osteoblast invasion. This adaptive mechanism, along with biofilm formation, is associated with agr dysfunction, which can be routinely assessed by delta-toxin detection using MALDI-TOF spectrum analysis, possibly providing clinicians with a diagnostic marker of BJI chronicity at the time of diagnosis

Cationic Interdiffusion at the SOFC Electrolyte/Cathode Interface in La2Mo2O9/La0.8Sr0.2MnO3-δ

In this work cation diffusion between a La2Mo2O9 (LM) ionic conductor and the conventional Solid Oxide Fuel Cell (SOFC) cathode material La0.8Sr0.2MnO3-δ (LSM), was probed using secondary ion mass spectrometry (SIMS), and diffusion coefficients of Sr, Mo and Mn cations within both materials evaluated. Diffusion coefficients extracted from samples with a Sr solution deposited on the LM pellets and from a Mo solution deposited on LSM pellets were found to be orders of magnitude higher than the cross-diffusion through the interface between two dense pellets in direct contact. These differences may be due to uncertainty in determining the interface position, or to a real dependence on the source of the diffusing cation. In the most favorable case, that of pellets in direct contact, extrapolation of diffusion coefficients down to a typical SOFC operating temperature, 800 °C, show that Mo diffusion in LSM (diffusion coefficient ∼ 10−14 cm2.s−1) is much higher than Sr or Mn diffusion in LM, and incompatible with use in a SOFC device, unless an efficient buffer layer is used

Linezolid in the Starter Combination for Multidrug-Resistant Tuberculosis: Time to Move on to Group Four?

International audienceLinezolid (LNZ), a group 5 antituberculous drug (unclear efficacy), was used in the starter regimens of 23 adults with multidrug-resistant tuberculosis. The LNZ-containing regimens were effective in achieving culture conversions and relapse-free outcomes. The most frequent LNZ-related side effect was neuropathy. We propose that LNZ should be reclassified among bactericidal second-line drugs

F-18-FDG PET/CT as a central tool in the shift from chronic Q fever to Coxiella burnetii persistent focalized infection: A consecutive case series

International audienceBecause Q fever is mostly diagnosed serologically, localizing a persistent focus of Coxiella burnetii infection can be challenging. F-18-fluorodeoxyglucose positron emission tomography/computed tomography (F-18-FDG PET/CT) could be an interesting tool in this context.We performed a retrospective study on patients diagnosed with C burnetii infection, who had undergone F-18-FDG PET/CT between 2009 and 2015. When positive F-18-FDG PET/CT results were obtained, we tried to determine if it changed the previous diagnosis by discovering or confirming a suspected focus of C burnetii infection.One hundred sixty-seven patients benefited from F-18-FDG PET/CT. The most frequent clinical subgroup before F-18-FDG PET/CT was patients with no identified focus of infection, despite high IgG1 serological titers (34%). For 59% (n=99) of patients, a hypermetabolic focus was identified. For 62 patients (62.6%), the positive F-18-FDG PET/CT allowed the diagnosis to be changed. For 24 of them, (38.7%), a previously unsuspected focus of infection was discovered. Forty-two (42%) positive patients had more than 1 hypermetabolic focus. We observed 21 valvular foci, 34 vascular foci, and a high proportion of osteoarticular localizations (n=21). We also observed lymphadenitis (n=27), bone marrow hypermetabolism (n=11), and 9 pulmonary localizations.We confirmed that(18)F-FDG PET/CT is a central tool in the diagnosis of C burnetii focalized persistent infection. We proposed new diagnostic scores for 2 main clinical entities identified using F-18-FDG PET/CT: osteoarticular persistent infections and lymphadenitis