Demonstrating the In Vitro and In Situ Antimicrobial Activity of Oxide Mineral Microspheres: An Innovative Technology to Be Incorporated into Porous and Nonporous Materials.

The antimicrobial activity of surfaces treated with zinc and/or magnesium mineral oxide microspheres is a patented technology that has been demonstrated in vitro against bacteria and viruses. This study aims to evaluate the efficiency and sustainability of the technology in vitro, under simulation-of-use conditions, and in situ. The tests were undertaken in vitro according to the ISO 22196:2011, ISO 20473:2013, and NF S90-700:2019 standards with adapted parameters. Simulation-of-use tests evaluated the robustness of the activity under worst-case scenarios. The in situ tests were conducted on high-touch surfaces. The in vitro results show efficient antimicrobial activity against referenced strains with a log reduction of >2. The sustainability of this effect was time-dependent and detected at lower temperatures (20 ± 2.5 °C) and humidity (46%) conditions for variable inoculum concentrations and contact times. The simulation of use proved the microsphere's efficiency under harsh mechanical and chemical tests. The in situ studies showed a higher than 90% reduction in CFU/25 cm2 per treated surface versus the untreated surfaces, reaching a targeted value of <50 CFU/cm2. Mineral oxide microspheres can be incorporated into unlimited surface types, including medical devices, to efficiently and sustainably prevent microbial contamination.

A Myrtus communis extract enriched in myrtucummulones and ursolic acid reduces resistance of Propionibacterium acnes biofilms to antibiotics used in acne vulgaris.

BACKGROUND: Recent works present evidence of Propionibacterium acnes growing as a biofilm in cutaneous follicles. This formation of clusters is now considered as an explanation for the in vivo resistance of P. acnes to the main antimicrobials prescribed in acne vulgaris. PURPOSE: Our objective was to explore this hypothesis and propose a new therapeutic approach focusing on anti-biofilm activity of Myrtacine(®) New Generation (Mediterranean Myrtle extract-Botanical Expertise P. Fabre) alone or combined with antibiotics. METHODS/RESULTS: Using in vitro models able to promote the growth of adhered bacteria, the loss of sensitivity of P. acnes biofilms (48 h) towards erythromycin and clindamycin was checked considering either sensitive or resistant strains. In the same time, the activity of Myrtacine(®) New Generation against biofilm formation and mature biofilm (48 h) was evaluated. Using a dynamic model of biofilm formation, we noted an inhibition of biofilm formation (addition of Myrtacine(®) New Generation at T 0) and a significant effect on mature biofilm (48 h) for 5 min of contact. This effect was also checked using the static model of biofilm formation for Myrtacine(®) New Generation concentrations ranging from 0.03% to 0.0001%. A significant, dose-dependent anti-biofilm effect was observed and notable even at a concentration lower than the active concentration on planktonic cells, i.e. 0.001%. Finally, the interest of the combination of Myrtacine(®) New Generation with antibiotics was explored. An enhanced efficacy was noted when erythromycin (1000 mg/l) or clindamycin (500 mg/l) was added to 0.001% Myrtacine(®), leading to significant differences in comparison to each compound used alone. CONCLUSION: The efficiency of Myrtacine(®) New Generation on P. acnes biofilm alone or combined with antibiotics was demonstrated and can lead to consider it as a potent adjunctive product efficient during the antibiotic course for acne vulgaris treatment.

Synthesis, antibacterial and antifungal activities of bifonazole derivatives.

Two series of chlorinated benzhydryl imidazole and triazole derivatives were synthesized and tested in vitro against representative strains of potent pathogenic bacteria (Staphylococcus aureus CIP 4.83, Escherichia hirae CIP 5855, Pseudomonas aeruginosa CIP 82118, Escherichia coli CIP 53126) and fungi (Aspergillus niger IP 1431.83, Candida albicans IP 48.72, Candida krusei IP 208.52, Trichophython rubrum IP 1657.86). Most of these compounds were devoid of any antimicrobial activity, but several of them inhibited T. rubrum with MIC values in the range of 0.125 to 32 µg/mL, similar or superior to those of bifonazole and clotrimazole, used as standard controls. The replacement of the imidazole ring with a triazole moiety in these compounds led to derivatives with less antifungal activity. A preliminary SAR was undertaken on the effect of the number and the position of chlorine atoms on the distribution of negative charge on the surface of some compounds on antifungal activity.