In vitro antifungal activity and phytochemical characterization of Eugenia uniflora, Libidibia ferrea and Psidium guajava

The aim of this study was evaluate the in vitro antifungal activity of crude extracts from Eugenia uniflora, Libidibia ferrea and Psidium guajava. The extracts were obtained by turbo-extraction using water (AQ) or acetone-water (AC-W) (7:3, v/v) as solvents and lyophilized to obtain the crude extracts (CE). The CE were characterized by UV-Vis, TLC and HPLC. The activity of CEs was investigated against clinical isolates of Candida spp. and the Minimum Inhibitory Concentration (MIC), MIC50 and MIC90 were determinated. The analysis by TLC showed that all CEs presented polyphenols (flavonoids and tannins). The CEs from E. uniflora showed higher amount of polyphenols (30.35 ± 2.15%, AC-W) and the HPLC analysis revealed the tannins in all extracts. The CEs of E. uniflora showed MIC range from 1.9 to 500.0 µg/mL, and lower values of MIC50 and MIC90 against non-albicans Candida isolates. Regarding L. ferrea and P. guajava, the results showing MIC from 3.9 to 1000.0 µg/mL (CE-AQ) against C. albicans. The results demonstrate antifungal performance from CE against various species of Candida spp., suggesting that the herbal species may be use as new potential antifungal agents. Additionally, the polyphenol content can play a pivotal role in the antifungal properties of CE.

Risk assessment of the occurrence of aflatoxin and fungi in peanuts and cashew nuts

In the present study, the occurrence of fungi and aflatoxins (AFs) in peanut and cashew nut samples was investigated. Mycological analysis revealed the presence of fungi in 58.8% of samples, and assessment of AFs by chromatographic methods revealed that 52.9% were contaminated by AFs. AFB1 was the principal component in all AF-contaminated samples, with a mean level of 14.0, and 1.08 µg/kg in peanut and cashew nut, respectively. Eleven samples (32.4%) exceeded the total AF maximum level (4 µg/kg) and 8 samples (23.5%) exceeded the AFB1 (2 µg/kg) established by the European Commission. Our findings suggest that the incidence of AFs emphasizes the need for regular monitoring and a more stringent food safety system to control AFs at the lowest possible levels in peanuts and cashew nuts. The hypothetical dietary exposure suggests that the food products evaluated may significantly contribute to the overall human exposure

Superoxide dismutases and glutaredoxins have a distinct role in the response of Candida albicans to oxidative stress generated by the chemical compounds menadione and diamide

To cope with oxidative stress, Candida albicans possesses several enzymes involved in a number of biological processes, including superoxide dismutases (Sods) and glutaredoxins (Grxs). The resistance of C. albicans to reactive oxygen species is thought to act as a virulence factor. Genes such as SOD1 and GRX2, which encode for a Sod and Grx, respectively, in C. albicans are widely recognised to be important for pathogenesis. We generated a double mutant, Δgrx2/sod1, for both genes. This strain is very defective in hyphae formation and is susceptible to killing by neutrophils. When exposed to two compounds that generate reactive oxygen species, the double null mutant was susceptible to menadione and resistant to diamide. The reintegration of the SOD1 gene in the null mutant led to recovery in resistance to menadione, whereas reintegration of the GRX2 gene made the null mutant sensitive to diamide. Despite having two different roles in the responses to oxidative stress generated by chemical compounds, GRX2 and SOD1 are important for C. albicans pathogenesis because the double mutant Δgrx2/sod1 was very susceptible to neutrophil killing and was defective in hyphae formation in addition to having a lower virulence in an animal model of systemic infection.

The persistence of multifocal colonisation by a single ABC genotype of Candida albicans may predict the transition from commensalism to infection

Candida albicans is a common member of the human microbiota and may cause invasive disease in susceptible populations. Several risk factors have been proposed for candidaemia acquisition. Previous Candida multifocal colonisation among hospitalised patients may be crucial for the successful establishment of candidaemia. Nevertheless, it is still not clear whether the persistence or replacement of a single clone of C. albicans in multiple anatomical sites of the organism may represent an additional risk for candidaemia acquisition. Therefore, we prospectively evaluated the dynamics of the colonising strains of C. albicans for two groups of seven critically ill patients: group I included patients colonised by C. albicans in multiple sites who did not develop candidaemia and group II included patients who were colonised and who developed candidaemia. ABC and microsatellite genotyping of 51 strains of C. albicans revealed that patients who did not develop candidaemia were multiply colonised by at least two ABC genotypes of C. albicans, whereas candidaemic patients had highly related microsatellites and the same ABC genotype in colonising and bloodstream isolates that were probably present in different body sites before the onset of candidaemia.

Pathogenicity characteristics of stocked and fresh yeasts strains

Com o objetivo de avaliar a patogenicidade de leveduras de interesse médico, foram selecionadas 15 amostras preservadas em óleo mineral na Micoteca URM, Centro de Ciências Biológicas, Universidade Federal de Pernambuco e 15 isolados recentes, provenientes de amostras clínicas de pacientes com AIDS, internados no Hospital das Clínicas, Centro de Ciências da Saúde, Universidade Federal de Pernambuco. Com relacão as características de patogenicidade, foram avaliados a capacidade desses microorganismos crescerem a 37ºC, bem como apresentarem atividade de fosfolipase e protease. As 30 amostras cresceram a 37ºC e apresentaram atividade quantitativa de protease, entretanto não apresentaram essa atividade quando testadas em meio sólido. Das 15 amostras preservadas, 13 (86,66 per center) apresentaram atividade fosfolipase positiva e duas (13,34 per center) atividade fosfolipásica negativa e das 15 amostras isoladas de pacientes com AIDS, quatro (26,66 per center) apresentaram atividade de fosfolipase positiva e 11 (73,34 per center) apresentaram atividade fosfolipásica negativa.

Yeasts isolated from clinical samples of aids patients

In order to investigate yeasts in oropharyngeal secretion, urine, sputum and inguinal scales from AIDS patients, clinical samples were collected from one hundred patients interned in the Infectious and Parasitic Diseases Sector of the Hospital das Clínicas of the Universidade Federal de Pernambuco and in Hospital Universitário Osvaldo Cruz of the Universidade de Pernambuco. Yeasts were isolated from seenty-two out of one hundred and eight clinical samples. The isolated yeasts were: Candida albicans (sixty-two isolates), Candida tropicalis (four isolates), Candida glabrata (two isolates), Candida parapsilosis (two isolates), Candida krusei (one isolate) and Trichosporon pullulans (one isolate).

Trichosporon pullulans (Lidner) Diddens & Lodder isolated from the oral cavity of AIDS patient

Trichosporon has been reported as a remarkable emerging pathogen and usually occurs in imunodrepressed patients. An oropharyngeal secretion sample was collected from a patient with AIDS, at the Sector of Infectious and Parasitic Diseases, Osvaldo Cruz University Hospital, Pernambuco State, Brazil. No yeast cells or arthroconidia were observed in the direct exam, but a culture was positive for Trichosporon pullulans, which is being reported in an AIDS patient for the first time