Staphylococcus succinus Infective Endocarditis, France.

Infective endocarditis is a rare condition in humans and is associated with high illness and death rates. We describe a case of infective endocarditis caused by Staphylococcus succinus bacteria in France. We used several techniques for susceptibility testing for this case to determine the oxacillin profile.

High Prevalence of OXA-23 Carbapenemase-Producing Proteus mirabilis among Amoxicillin-Clavulanate-Resistant Isolates in France.

In this multicentric study performed in 12 French hospitals, we reported that 26.9% (14/52) of the amoxicillin-clavulanate-resistant Proteus mirabilis isolates produced the OXA-23 carbapenemase. We found that an inhibition zone diameter of <11 mm around the amoxicillin-clavulanate disc was an accurate screening cutoff to detect these OXA-23 producers. We confirmed by whole-genome sequencing that these OXA-23-producers all belonged to the same lineage that has been demonstrated to disseminate OXA-23 or OXA-58 in P. mirabilis.

Performance of rapid antimicrobial susceptibility testing by disk diffusion on MHR-SIR agar directly on urine specimens.

The standard method for the diagnosis of urinary tract infections is urine culture that requires 18-48 h for the identification of the bacteria and an additional 24 h until the results of antimicrobial susceptibility testing (AST) are available. We evaluated here a rapid AST method by disc diffusion performed directly on urine samples with a delay of 8 h. A total of 245 urine samples with monobacterial Gram negative observed on microscopy were tested in parallel by two AST methods. Rapid AST method was performed directly on urine samples using Rapid Mueller-Hinton (MHR-SIR) with 8-h incubation before reading and standard method was performed as usual. We compared the categorical agreement and the correlation between the diameters obtained by standard method and by MHR-SIR directly on urine samples. Over the 5285 tested combinations, we observed 5172 (97.9%) categorical agreement, 82 (1.5%) minor errors, 17 (0.3%) major errors, and 14 (0.3%) very major errors. Our results showed an excellent categorical agreement and correlations between diameters for MHR-SIR and standard methods. MHR-SIR performed directly on urine samples with monomicrobial Enterobacteriacae can predict the result of overall AST profile in 8 h with reliable results. The main advantage of MHR-SIR is that it offers the possibility of obtaining results 40 h earlier than conventional AST. The cost is estimated for less than 6 USD for 16 antibiotics, chosen by the microbiologist.

Biofilm of Cutibacterium acnes: a target of different active substances.

BACKGROUND: Acne vulgaris is a chronic inflammatory dermatosis. Cutibacterium acnes plays a crucial role in the acne pathophysiology. Recent works present evidence of C. acnes growing as a biofilm in cutaneous follicles. This development is currently considered one of the leading causes of C. acnes in vivo persistence and resistance to antimicrobials used to treat acne. OBJECTIVE: Our objective was to evaluate the effects of various active compounds (clindamycin, erythromycin, doxycycline, and myrtle extract) on eight distinct, well-characterized strains of C. acnes following their growth in biofilm mode. METHODS/RESULTS: Cutibacterium acnes isolates from phylotypes IA1 and IA2 produce more biofilm than other phylotypes. No antibiotic effect was observed either during the curative test or preventive test. Myrtle extract at 0.01% (w/v) showed significant efficacy on the biofilm for C. acnes strains (curative assays). Furthermore, it appear that myrtle extract and doxycycline together reduce the overall biomass of the biofilm. A significant dose-dependent effect was observed during the preventive test, greater than the one observed under curative conditions, with an important loss of activity of the myrtle extract observed from 0.001% (w/v) concentration onwards. Transmission electron microscopy showed that bacteria treated with myrtle extract grew biofilms much less frequently than untreated bacteria. Additionally, when the quantity of myrtle extract grew, the overall number of bacteria dropped, indicating an additional antibacterial action. CONCLUSION: These findings support the hypothesis that the different C. acnes phylotypes have various aptitudes in forming biofilms. They also suggest that myrtle extract is a promising alternative as an anti-biofilm and antibacterial agent in fighting diseases caused by planktonic and biofilm C. acnes.

Comparative effectiveness of empirical antibiotic treatments in methicillin-susceptible Staphylococcus aureus infective endocarditis: A post hoc analysis of a prospective French cohort study.

OBJECTIVES: The empirical treatment of infective endocarditis is still debated. The aim of this study was to compare the impact of empirical treatment with antistaphylococcal penicillin (ASP) or cefazolin vs. other treatments in methicillin-susceptible Staphylococcus aureus (MSSA) endocarditis. METHODS: A post hoc analysis of a prospective cohort study of patients hospitalized in a French reference centre with MSSA endocarditis was conducted between 2013 and 2022. The primary outcome was the duration of bacteraemia under treatment. RESULTS: Of the 208 patients included, 101 patients (48.6%) were classified in the reference group (ASP or cefazolin) and 107 (52.4%) in the non-reference group. Empirical treatment with ASP/cefazolin was associated with a shorter duration of bacteraemia compared to other treatments (3.6 d vs. 4.6 d, P = 0.01). This difference was not corrected by the addition of an aminoglycoside (3.6 d vs. 4.7 d, P < 0.01). In multivariate analysis, empirical treatment with ASP/cefazolin was associated with a duration of bacteraemia ≤72 h (P = 0.02), whereas endocarditis on native valves (P = 0.01), and intracardiac abscess were associated with longer duration of bacteraemia (P = 0.01). CONCLUSIONS: Empirical treatment of endocarditis with ASP or Cefazolin is more effective than other treatments in MSSA endocarditis, even when the other treatments are combined with aminoglycosides.

Synovial calprotectin: A potentially useful biomarker for the diagnosis of Kingella kingae native arthritis.

Kingella kingae is a bacteria involved in developing arthritis in children. Its diagnosis remains difficult. We report a case for which a new biomarker, calprotectin measured in the synovial fluid, was strongly positive and a specific molecular test was the only way to diagnose it specifically.