Guava (Psidium guajava L.), is adapted to tropical and subtropical climates, and, in addition to its nutritional value, has great medicinal potential. One of the medicinal effects is antibacterial, and this can be identifi ed from the phytochemicals present in its various parts, especially the leaf, which contains fl avonoids, phenols, and tannins, as well as phytocomposites with antibacterial action. Therefore, the interaction of this plant with arbuscular mycorrhizal fungi and Meloidogyne enterolobii is a biotechnological resource that can increase the production of secondary metabolites so that the guava ethanolic extract is effective against multidrug-resistant bacterial strains. Therefore, the objective of this study was to test the inhibitory action of mycorrhizal guava leaf extract and Meloidogyne enterolobii on strains of Klebsiella pneumoniae carbapenemase.Guava seedlings from cuttings were inoculated with Acaulospora longula, and later with Meloidogyne enterolobii; the leaves were harvested at two maturation times of the plant and placed in an oven. Next, a leaf extract was prepared using ethanol as a solvent. The extract was tested in multidrug-resistant strains of K. pneumoniae carbapenemase from operative wounds using disc diffusion methodology. The plant-AMF-phytonematode interaction positively potentialize the inhibitory action of guava leaf ethanolic extract on multidrug-resistant bacterial strains.

The development of alternative (and free-of-antibiotics) antibacterial and antibiofilm agents is an important strategy to circumvent the resistance of bacteria to antibiotics. Herein, we explore the production of mixed oxides by incorporating silver nanoparticles in titanium dioxide as a silver concentration-dependent antibacterial agent that is further incorporated in Tilapia fish skin (a promising prototype of xenograft), integrating the antibacterial activity of mixed oxide into the intrinsic properties of Tilapia skin. The antibiofilm activity of samples prepared with high concentrations of silver (10 wt% of precursor AgNO3) has been considered a good antibiofilm response. The influence of silver content is also observed with respect to the minimum bactericidal concentration, which is reduced to 3.13 mg/mL with a characteristic kill time in the order of 30 min that is associated with antibiofilm activity in biofilm-forming strains of Staphylococcus aureus. These results indicate that modified Tilapia fish skin acquires antibacterial behavior and can be explored for xenografts with prospective applications in the light-dependent actuation of TiO2-based compounds.

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