Significance and impact of the study: Microorganisms such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica subsp. enterica serovar Enteritidis and S. enterica subsp. enterica serovar Typhimurium can cause contamination in fresh or processed food products. The use of natural compounds, for instance carvacrol, can be an alternative to the use of synthetic bactericides. Our data demonstrate that the carvacrol nanoemulsion (NECV) had stability for up to 90 days, promoted inhibitory activity against all evaluated microorganisms , and improved antimicrobial activity against P. aeruginosa, S. aureus and S. Typhimurium when compared to free oil. These findings suggest that NECV can be evaluated as a food preservative to promote antimicrobial activity.

This study elaborated different formulations with xique-xique (Pilosocereus gounellei) cladode, passion fruit and lime juice and sugar cane syrup. The formulated beverages were subjected to physical and physicochemical analysis, determination of total carotenoid, total flavonoid and total phenolic compound contents, as well as of their antioxidant activity (ABTS and FRAP method), organic acid, sugar and phenolic compound profile during 21 days of refrigeration storage (4 °C). Significant variations were found among formulated beverages for most of the measured parameters during storage. Beverages with xique-xique juice were less acidic (7.90–10.27 g/100 mL) than beverages without this juice (11.66–12.76 g/100 mL). Beverages with xique-xique juice had overall higher contents of bioactive compounds and higher antioxidant activity when compared to the control formulation. Beverages with the highest xique-xique juice concentrations had the highest contents of carotenoids (51.51–59.27 µg/100 mL), flavonoids (1.39–2.15 mg CE/100 mL), phenolic compounds (68.49–115.66 mg EGA/100 mL) and antioxidant activity, as measured by ABTS (0.71–0.84 µmol Trolox/mL) and FRAP (0.33–0.39 µmol Trolox/mL). These results indicate that the incorporation of xique-xique cladode juice in these mixed beverages enhanced their bioactive properties, especially of antioxidant compounds, enabling the development of a new product with potential functional properties to the beverage industry.

Antimicrobial activity of pyocyanin against competing organisms of Pseudomonas aeruginosa is related to the oxidative stress that the compound promotes in susceptible cells. The objective of this work was to produce, extract and verify the activity of pyocyanin in planktonic and sessile forms from clinical strains, Staphylococcus aureus UFPEDA 02 and Escherichia coli UFPEDA 224. About 600 µg/mL of pyocyanin were obtained. The planktonic cells were highly sensitive. The MIC determined for S. aureus UFPEDA 02 and E. coli UFPEDA 224 were 18.75 and 37.5 µg/mL, respectively. The pyocyanin demonstrated biocidal effect against S. aureus UFPEDA 02. On the other hand, pyocyanin was not active in either sessile strain. The presence of the pigment allowed a greater adherence of the strains, forming more robust biofilms compared to the control. S. aureus UFPEDA 02 and E. coli UFPEDA 224 presented moderate and high hydrophobicity, respectively. Glass and dolomite surfaces were tested in the in vitro biofilm test. Both strains formed the biofilm better on the dolomite surface, obtaining a cell concentration (MPN/cm2) in the order of 3 log units after 48h of incubation.

PURPOSE: Certain ocular resident or pathogenic microbes may remain viable in the presence of multi-purpose disinfectant solutions (MPDSs), subsequently developing biofilms inside contact lens storage cases (CLSCs) which pose a risk of infection to wearers. This study evaluated the formation of ocular microbiota biofilms exposed to three top selling MPDS. METHODS: Crystal violet assay was carried out for the verification of biofilm formation. The in vitro assays evaluated Pseudomonas aeruginosa UFPEDA 416 and Staphylococcus aureus UFPEDA 02 exposure of 48 h to MPDS, as well as the use of 40 KHz ultrasound at the beginning and with 24 h immersion in the MPDS. Subsequently, in vivo assays evaluated the formation of microbial biofilms on the CLSC walls containing silicone-hydrogel contact lenses immersed in MPDS from 15 healthy volunteer patients, who had been wearing the lenses for 7 days. RESULTS: Biofilms were inhibited by 26%–98% in the in vitro assays, with a statistically significant difference only for P. aeruginosa UFPEDA 416 exposed to diluted MPDS. Most inhibitions occurred moderately and weakly. In addition, adherent cells were detected in more than 90% of the tests. Biofilm was not inhibited in more than one third of the results, nor was it disturbed, especially with the ultrasound treatments. The average of obtained optical densities at 590 nm was between 0.6 and 0.8 in the in vivo assays. The results were similar between the CLSC right and left wells. There was a correlation between microbial biofilm formation and the type of MPDS tested, with statistical difference between the three treatments. CONCLUSION: MPDS promoted a partial inhibition of microbial biofilm formation but only one MPDS proved to be more effective in vitro and in vivo. This study, however, could not distinguish the effect of possible errors in the good hygiene practices of the users.

Efluentes líquidos gerados por laboratórios de pesquisa não recebem a devida atenção em países em desenvolvimento, representando riscos em potencial em termos de contaminação de corpos hídricos superficiais e subterrâneos. Esta minirrevisão foi elaborada por discentes de Pós-Graduação em Biotecnologia, como trabalho final da Disciplina que trata de impactos ambientais e estratégias de transformação dos resíduos por atividade biológica. O documento disserta especialmente sobre o impacto destes resíduos em águas marinhas, bem como a perturbação dos serviços ecossistêmicos.