Yeast-amoeba interaction influences murine cryptococcosis.

The virulence of Cryptococcus spp. is modulated in the natural environment through interaction with abiotic and biotic factors, and this can occasionally have implications for the progression of cryptococcosis in mammals. Hence, we evaluated whether the prior interaction of highly virulent Cryptococcus gattii strain R265 with Acanthamoeba castellanii influenced the progression of cryptococcosis. The influence of the capsule on endocytosis was evaluated using amoeba and yeast morphometrics. Mice were intratracheally infected with yeast re-isolated from the amoeba (Interaction), yeast without prior contact with the amoeba (Non-Interaction), or sterile phosphate-buffered saline (SHAM). Morbidity signs and symptoms were monitored during the survival curve, while cytokine and fungal burden measurements and histopathological analysis were performed on the 10th day post infection. Morbidity and mortality parameters in experimental cryptococcosis were influenced by the prior interaction of yeast with amoeba, which led to phenotypic changes in the cryptococcal cells, polysaccharide secretion, and their tolerance to oxidative stress. Our results suggest that a prior yeast-amoeba interaction modulates yeast virulence, which is associated with a greater tolerance to oxidative stress related to the exo-polysaccharide content and influences the progression of cryptococcal infection.

Hydroalcoholic Leaf Extract of Punica granatum, alone and in Combination with Calcium Hydroxide, Is Effective against Mono- and Polymicrobial Biofilms of Enterococcus faecalis and Candida albicans.

Failures in endodontic treatments are mostly associated with the difficulty in eradicating microbes of the root canal system, highlighting the need to develop novel effective antimicrobials. Punica granatum (pomegranate) leaf hydroalcoholic extract may be a potential alternative in canal dressing, owing to its antimicrobial properties. The objective of this study was to evaluate the antimicrobial activity of hydroalcoholic leaf extract of Punica granatum (HEPg) alone or in combination with calcium hydroxide (Ca(OH)2) against Enterococcus faecalis and Candida albicans in isolation and in mono- and polymicrobial biofilms. Microdilution tests in broth and assays for inhibition of biofilm formation were carried out to evaluate the antimicrobial properties of HEPg and HEPg + Ca(OH)2 against Enterococcus faecalis and Candida albicans. The cytotoxicity of HEPg in HaCaT cells was evaluated by MTT assay. HEPg and HEPg + Ca(OH)2 exerted significant antimicrobial activity against planktonic cells and mono- and polymicrobial biofilms. The combination of Punica granatum extract with Ca(OH)2 appears to be a promising alternative in endodontic treatments, which could be tested in vivo to confirm the efficacy of this mixture in disinfecting root canal systems.