Biofilm of Cutibacterium acnes : a target of different active substances

International audienceAbstract 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 IA 1 and IA 2 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

Emergence of methicillin resistant Staphylococcus epidermidis resistant to linezolid: activity of ceftaroline versus ceftobiprole in a French University French Hospital

International audienceNo abstract availabl

High prevalence of OXA-23 carbapenemase-producing Proteus mirabilis among amoxicillin-clavulanate resistant isolates in France

International audienceIn 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 inhibition zone diameter less than 11 mm around amoxicillin/clavulanate disc was an accurate screening cut-off 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

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

International audienceObjectives: 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 versus 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 center with MSSA endocarditis was conducted between 2013 and 2022. The primary outcome was the duration of bacteremia 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 bacteremia compared to other treatments (3.6 days versus 4.6 days, p=0.01). This difference was not corrected by the addition of an aminoglycoside (3.6 days versus 4.7 days, p<0.01). In multivariate analysis, empirical treatment with ASP/cefazolin was associated with a duration of bacteremia ≤72 hours (p=0.02), whereas endocarditis on native valves (p=0.01), and intracardiac abscess were associated with longer duration of bacteremia (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. Text

Evaluation of ceftolozane-tazobactam susceptibility on a French nationwide collection of Enterobacterales

International audienceObjectives: Ceftolozane-tazobactam (C/T) proved its efficacy for the treatment of infections caused by non-carbapenemase producing Pseudomonas aeruginosa and Enterobacterales. Here, we aimed to provide susceptibility data on large series of Enterobacterales since the revision of EUCAST categorization breakpoints in 2020.Methods: First, C/T susceptibility was determined on characterized Enterobacterales resistant to 3rd generation cephalosporins (3GC) (ESBL production or different levels of AmpC overexpression) (n=213) and carbapenem resistant Enterobacterales (CRE) (n=259) including 170 carbapenemase producers (CPE). Then, 1,632 consecutive clinical Enterobacterales responsible for infection were prospectively collected in 23 French hospitals. C/T susceptibility was determined by Etest® (biomérieux) and broth microdilution (BMD) (Sensititre™, Thermo Scientific) to perform method comparison.Results: Within the collection isolates, 88% of 3GC resistant strains were susceptible to C/T, with important variation depending on the resistance mechanism: 93% vs 13% susceptibility for CTX-M and SHV-ESBL producers, respectively. Only 20% of the CRE were susceptible to C/T. Among CPE, 80 % of OXA-48-like producers were susceptible to C/T, whereas all metallo-β-lactamase producers were resistant. The prospective study revealed that 95.6% of clinical isolates were susceptible to C/T. Method comparison performed on these 1,632 clinical isolates demonstrated 99 % of categorization agreement between MIC to C/T determined by Etest® compared to BMD (reference) and only 74% of essential agreement.Conclusion: Overall, C/T showed good activity against wild-type Enterobacterales, AmpC producers and ESBL-producing E. coli but is less active against ESBL-producing K. pneumoniae and CRE. Etest® led to an underestimation of the MICs in comparison to BMD

Evaluation of ceftolozane-tazobactam susceptibility on a French nationwide collection of Enterobacterales

International audienceObjectives: Ceftolozane-tazobactam (C/T) proved its efficacy for the treatment of infections caused by non-carbapenemase producing Pseudomonas aeruginosa and Enterobacterales. Here, we aimed to provide susceptibility data on large series of Enterobacterales since the revision of EUCAST categorization breakpoints in 2020.Methods: First, C/T susceptibility was determined on characterized Enterobacterales resistant to 3rd generation cephalosporins (3GC) (ESBL production or different levels of AmpC overexpression) (n=213) and carbapenem resistant Enterobacterales (CRE) (n=259) including 170 carbapenemase producers (CPE). Then, 1,632 consecutive clinical Enterobacterales responsible for infection were prospectively collected in 23 French hospitals. C/T susceptibility was determined by Etest® (biomérieux) and broth microdilution (BMD) (Sensititre™, Thermo Scientific) to perform method comparison.Results: Within the collection isolates, 88% of 3GC resistant strains were susceptible to C/T, with important variation depending on the resistance mechanism: 93% vs 13% susceptibility for CTX-M and SHV-ESBL producers, respectively. Only 20% of the CRE were susceptible to C/T. Among CPE, 80 % of OXA-48-like producers were susceptible to C/T, whereas all metallo-β-lactamase producers were resistant. The prospective study revealed that 95.6% of clinical isolates were susceptible to C/T. Method comparison performed on these 1,632 clinical isolates demonstrated 99 % of categorization agreement between MIC to C/T determined by Etest® compared to BMD (reference) and only 74% of essential agreement.Conclusion: Overall, C/T showed good activity against wild-type Enterobacterales, AmpC producers and ESBL-producing E. coli but is less active against ESBL-producing K. pneumoniae and CRE. Etest® led to an underestimation of the MICs in comparison to BMD

Evaluation of ceftolozane-tazobactam susceptibility on a French nationwide collection of Enterobacterales

International audienceObjectives: Ceftolozane-tazobactam (C/T) proved its efficacy for the treatment of infections caused by non-carbapenemase producing Pseudomonas aeruginosa and Enterobacterales. Here, we aimed to provide susceptibility data on large series of Enterobacterales since the revision of EUCAST categorization breakpoints in 2020.Methods: First, C/T susceptibility was determined on characterized Enterobacterales resistant to 3rd generation cephalosporins (3GC) (ESBL production or different levels of AmpC overexpression) (n=213) and carbapenem resistant Enterobacterales (CRE) (n=259) including 170 carbapenemase producers (CPE). Then, 1,632 consecutive clinical Enterobacterales responsible for infection were prospectively collected in 23 French hospitals. C/T susceptibility was determined by Etest® (biomérieux) and broth microdilution (BMD) (Sensititre™, Thermo Scientific) to perform method comparison.Results: Within the collection isolates, 88% of 3GC resistant strains were susceptible to C/T, with important variation depending on the resistance mechanism: 93% vs 13% susceptibility for CTX-M and SHV-ESBL producers, respectively. Only 20% of the CRE were susceptible to C/T. Among CPE, 80 % of OXA-48-like producers were susceptible to C/T, whereas all metallo-β-lactamase producers were resistant. The prospective study revealed that 95.6% of clinical isolates were susceptible to C/T. Method comparison performed on these 1,632 clinical isolates demonstrated 99 % of categorization agreement between MIC to C/T determined by Etest® compared to BMD (reference) and only 74% of essential agreement.Conclusion: Overall, C/T showed good activity against wild-type Enterobacterales, AmpC producers and ESBL-producing E. coli but is less active against ESBL-producing K. pneumoniae and CRE. Etest® led to an underestimation of the MICs in comparison to BMD

Evaluation of ceftolozane-tazobactam susceptibility on a French nationwide collection of Enterobacterales

International audienceObjectives: Ceftolozane-tazobactam (C/T) proved its efficacy for the treatment of infections caused by non-carbapenemase producing Pseudomonas aeruginosa and Enterobacterales. Here, we aimed to provide susceptibility data on large series of Enterobacterales since the revision of EUCAST categorization breakpoints in 2020.Methods: First, C/T susceptibility was determined on characterized Enterobacterales resistant to 3rd generation cephalosporins (3GC) (ESBL production or different levels of AmpC overexpression) (n=213) and carbapenem resistant Enterobacterales (CRE) (n=259) including 170 carbapenemase producers (CPE). Then, 1,632 consecutive clinical Enterobacterales responsible for infection were prospectively collected in 23 French hospitals. C/T susceptibility was determined by Etest® (biomérieux) and broth microdilution (BMD) (Sensititre™, Thermo Scientific) to perform method comparison.Results: Within the collection isolates, 88% of 3GC resistant strains were susceptible to C/T, with important variation depending on the resistance mechanism: 93% vs 13% susceptibility for CTX-M and SHV-ESBL producers, respectively. Only 20% of the CRE were susceptible to C/T. Among CPE, 80 % of OXA-48-like producers were susceptible to C/T, whereas all metallo-β-lactamase producers were resistant. The prospective study revealed that 95.6% of clinical isolates were susceptible to C/T. Method comparison performed on these 1,632 clinical isolates demonstrated 99 % of categorization agreement between MIC to C/T determined by Etest® compared to BMD (reference) and only 74% of essential agreement.Conclusion: Overall, C/T showed good activity against wild-type Enterobacterales, AmpC producers and ESBL-producing E. coli but is less active against ESBL-producing K. pneumoniae and CRE. Etest® led to an underestimation of the MICs in comparison to BMD

Evaluation of ceftolozane-tazobactam susceptibility on a French nationwide collection of Enterobacterales

International audienceObjectives: Ceftolozane-tazobactam (C/T) proved its efficacy for the treatment of infections caused by non-carbapenemase producing Pseudomonas aeruginosa and Enterobacterales. Here, we aimed to provide susceptibility data on large series of Enterobacterales since the revision of EUCAST categorization breakpoints in 2020.Methods: First, C/T susceptibility was determined on characterized Enterobacterales resistant to 3rd generation cephalosporins (3GC) (ESBL production or different levels of AmpC overexpression) (n=213) and carbapenem resistant Enterobacterales (CRE) (n=259) including 170 carbapenemase producers (CPE). Then, 1,632 consecutive clinical Enterobacterales responsible for infection were prospectively collected in 23 French hospitals. C/T susceptibility was determined by Etest® (biomérieux) and broth microdilution (BMD) (Sensititre™, Thermo Scientific) to perform method comparison.Results: Within the collection isolates, 88% of 3GC resistant strains were susceptible to C/T, with important variation depending on the resistance mechanism: 93% vs 13% susceptibility for CTX-M and SHV-ESBL producers, respectively. Only 20% of the CRE were susceptible to C/T. Among CPE, 80 % of OXA-48-like producers were susceptible to C/T, whereas all metallo-β-lactamase producers were resistant. The prospective study revealed that 95.6% of clinical isolates were susceptible to C/T. Method comparison performed on these 1,632 clinical isolates demonstrated 99 % of categorization agreement between MIC to C/T determined by Etest® compared to BMD (reference) and only 74% of essential agreement.Conclusion: Overall, C/T showed good activity against wild-type Enterobacterales, AmpC producers and ESBL-producing E. coli but is less active against ESBL-producing K. pneumoniae and CRE. Etest® led to an underestimation of the MICs in comparison to BMD

Evaluation of ceftolozane-tazobactam susceptibility on a French nationwide collection of Enterobacterales

International audienceObjectives: Ceftolozane-tazobactam (C/T) proved its efficacy for the treatment of infections caused by non-carbapenemase producing Pseudomonas aeruginosa and Enterobacterales. Here, we aimed to provide susceptibility data on large series of Enterobacterales since the revision of EUCAST categorization breakpoints in 2020.Methods: First, C/T susceptibility was determined on characterized Enterobacterales resistant to 3rd generation cephalosporins (3GC) (ESBL production or different levels of AmpC overexpression) (n=213) and carbapenem resistant Enterobacterales (CRE) (n=259) including 170 carbapenemase producers (CPE). Then, 1,632 consecutive clinical Enterobacterales responsible for infection were prospectively collected in 23 French hospitals. C/T susceptibility was determined by Etest® (biomérieux) and broth microdilution (BMD) (Sensititre™, Thermo Scientific) to perform method comparison.Results: Within the collection isolates, 88% of 3GC resistant strains were susceptible to C/T, with important variation depending on the resistance mechanism: 93% vs 13% susceptibility for CTX-M and SHV-ESBL producers, respectively. Only 20% of the CRE were susceptible to C/T. Among CPE, 80 % of OXA-48-like producers were susceptible to C/T, whereas all metallo-β-lactamase producers were resistant. The prospective study revealed that 95.6% of clinical isolates were susceptible to C/T. Method comparison performed on these 1,632 clinical isolates demonstrated 99 % of categorization agreement between MIC to C/T determined by Etest® compared to BMD (reference) and only 74% of essential agreement.Conclusion: Overall, C/T showed good activity against wild-type Enterobacterales, AmpC producers and ESBL-producing E. coli but is less active against ESBL-producing K. pneumoniae and CRE. Etest® led to an underestimation of the MICs in comparison to BMD