Nanostructured Lipid Carriers Loaded with <i>Lippia sidoides</i> Essential Oil as a Strategy to Combat the Multidrug-Resistant <i>Candida auris</i>

The emerging pathogen Candida auris is an emerging fungal pathogen that was associated with nosocomial infectious outbreaks. Its worldwide incidence and the emerging multidrug-resistant strains highlight the urgency for novel and effective antifungal treatment strategies. Lippia sidoides essential oil (LSEO) proved antifungal activity, including anti-Candida. However, it may undergo irreversible changes when in contact with external agents without adequate protection. Herein, we encapsulated LSEO in nanostructured lipid carriers (NLC) through the hot emulsification method followed by sonication. NLC matrix was based on oleic acid and Compritol® 888, or a combination of carnauba wax and beeswax, stabilized by sodium dodecyl sulfate. Eight formulations were produced and characterized by the determination of the particle size (213.1 to 445.5 nm), polydispersity index (around 0.3), and ζ-potential (−93.1 to −63.8 mV). The antifungal activity of nanoparticles and LSEO against C. auris and the in vivo toxicity in Galleria mellonella model were also evaluated. Both NLC and LSEO exhibited potent activity against the yeast, with Minimum Inhibitory Concentration between 281 and 563 µg/mL, and did not evidence toxicity in the in vivo model. Therefore, this study confirms the viability of NLCs loaded with LSEO in combating drug-resistant pathogens as a potential new therapeutic strategy for managing of candidemia

Phenotypic and genotypic characterization of Salmonella Typhimurium isolates from humans and foods in Brazil.

Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) causes gastroenteritis in many countries. However, in Brazil there are few studies that have conducted a virulence characterization of this serovar. The aim of this study was to evaluate the virulence potential of S. Typhimurium strains isolated in Brazil. Forty S. Typhimurium strains isolated from humans (n = 20) and food (n = 20) from Brazil were studied regarding their invasion and survival in human epithelial cells (Caco-2) and macrophages (U937). Their virulence potential was determined using the Galleria mellonella larvae model combined with the analysis of virulence genes by whole genome sequencing (WGS). A total of 67.5% of the S. Typhimurium studied (32.5% isolated from humans and 35% isolated from food) invaded Caco-2 epithelial cells at levels similar to or greater than the S. Typhimurium SL1344 prototype strain. In addition, 37.5% of the studied strains (25% isolated from humans and 12.5% isolated from food) survived in U937 human macrophages at levels similar to or greater than SL1344. S. Typhimurium strains isolated from humans (40%) and food (25%) showed high or intermediate virulence in G. mellonella larvae after seven days exposure. Approximately, 153 virulence genes of chromosomal and plasmidial origin were detected in the strains studied. In conclusion, the ability of the S. Typhimurium to invade Caco-2 epithelial cells was strain dependent and was not related to the source or the year of isolation. However, S. Typhimurium strains isolated from humans showed greater survival rates in U937 human macrophages, and presented higher proportion of isolates with a virulent profile in G. mellonella in comparison to strains isolated from food suggesting that this difference may be related to the higher frequency of human isolates which contained plasmid genes, such as spvABCDR operon, pefABCD operon, rck and mig-5

Correction: Phenotypic and genotypic characterization of Salmonella Typhimurium isolates from humans and foods in Brazil.

[This corrects the article DOI: 10.1371/journal.pone.0237886.]