Maria Aparecida de Resende Stoianoff

Biodesulfurization: a mini review about the immediate search for the future technology

A major concern among the environmental agencies includes the emission of sulfurous gas into the environment. Consequently, the oil agencies are in constant search of alternative processes aiming the reduction of sulfur content in fuels. One of the technologies commonly used is the hydrodesulfurization (HDS), but this is a high-cost process that also requires high temperature and pressure. A complementary alternative to HDS is biodesulfurization (BDS) involving the use of specific microorganisms to the removal of sulfur present in the carbon chain, using the oxidation pathway “4S”, in which there is cleavage of carbon–sulfur bond, and maintaining the calorific value of the organic molecule. The BDS is a low-cost technique when compared with HDS. For this process to occur, activation of specific enzymes is needed, which is controlled by dszABC genes. Therefore, strategies to optimize this process have been of great importance to the oil refineries. For decades, attempts to try to implement BDS in the industry have been made, but difficulties in obtaining satisfactory results led the researchers to seek new knowledge about this bioprocess. The need of more studies concerning implementation on an industrial scale of this process is evident, since this biotechnology is a promising alternative to refineries in the near future.

Effectiveness of Flexible Gastrointestinal Endoscope Reprocessing

The practice of reprocessing endoscopes and its effectiveness was evaluated in 37 services. Contamination of at least 1 endoscope could be identified in 34 (91.6%) of 37 services. Bacteria, fungi, and/or mycobacteria were isolated from 84.6% (33/39) of the colonoscopes (110-32,000 colony-forming units [CFUs]/mL) and from 80.6% (50/62) of the gastroscopes (100-33,000 CFUs/mL). Not all services followed recommended guidelines. Therefore, patients who underwent gastrointestinal endoscopies were exposed to diverse pathogens.

Analysis of microbial load on surgical instruments after clinical use and following manual and automated cleaning

BACKGROUND We aimed to monitor the microbial load and identify the microorganisms recovered from surgical instruments after clinical use and following manual and automated cleaning. METHODS This experimental study was carried out in the Laboratory of Oral Microbiology and Anaerobes at the Federal University of Minas Gerais in Brazil. Microbial samples were taken from 125 surgical instruments used in 25 types of gastrointestinal surgeries. RESULTS The average microbial load was 93.1 CFU/100 mL after clinical use and 41 CFU/100 mL and 8.24 CFU/100 mL on instruments following 2 sequential steps of manual cleaning, respectively, and 75 CFU/100 mL and 16.1 CFU/100 mL on instruments after automated cleaning. Surgical wound classification significantly affected the microbial load recovered on instruments. Coagulase-negative Staphylococcus, Escherichia coli, Pseudomonas spp, Stenotrophomonas maltophilia, and Acinetobacter baumannii complex were recovered. CONCLUSIONS The average microbial load observed after the cleaning steps decreased, and the decrease in microbial load was more pronounced using the manual method compared with that observed using the automated method.

In vitro studies of the activity of dithiocarbamate organoruthenium complexes against clinically relevant fungal pathogens.

The in vitro antifungal activity of nine dirutheniumpentadithiocarbamate complexes C1–C9 was investigated and assessed for its activity against four different fungal species with clinical interest and related to invasive fungal infections (IFIs), such as Candida spp. [C. albicans (two clinical isolates), C. glabrata, C. krusei, C. parapsolisis, C. tropicalis, C.dubliniensis (six clinical isolates)], Paracoccidioides brasiliensis (seven clinical isolates), Cryptococcus neoformans and Sporothrix schenckii. All synthesized complexes C1–C9 and also the free ligands L1–L9 were submitted to in vitro tests against those fungi and the results are very promising, since some of the obtained MIC (minimal inhibitory concentration) values were very low (from 10−6 mol mL−1 to 10−8 mol mL−1) against all investigated clinically relevant fungal pathogens, except for C. glabrata, that the MIC values are close to the ones obtained for fluconazole, the standard antifungal agent tested. Preliminary structure-activity relations (SAR) might be suggested and a strong influence from steric and lipophilic parameters in the antifungal activity can be noticed. Cytotoxicity assays (IC50) showed that the complexes are not as toxic (IC50 values are much higher—30 to 200 fold—than MIC values). These ruthenium complexes are very promising lead compounds for novel antifungal drug development, especially in IFIs, one of most harmful emerging infection diseases (EIDs).

Influence of oxidation state of sulfur on the dissociation of [Tz‐(CH2)n‐S(O)m‐(CH2)n‐Tz + Na+] adducts generated by electrospray ionization (Tz = tetrazole ring; n = 2, 3; m = 0, 1, 2)

Sodium adducts of six organosulfur-α,ω-ditetrazole compounds (Tz-(CH(2))(n)-S(O)(m)-(CH(2))(n)-Tz; where Tz = tetrazole ring; n = 2, 3; m = 0, 1, 2) were generated via electrospray ionization (ESI) and their fragmentation pattern assessed via collision-induced dissociation (CID). Two main dissociation channels were observed: (a) losses of N(2) and HN(3) from the tetrazole rings; (b) cleavage of the C-S bond. The sulfoxides pass predominantly through the second fragmentation pathway, but for the sulfides and sulfones the tetrazole ring fragmentation occurs. Theoretical calculations at the B3LYP/6-31 + G(d,p) level indicate that for all the adducts (sulfide, sulfoxide, and sulfone) the dissociation pathway that leads to product ions arising from loss of N(2) was the most exothermic. Based on these results and assumptions, it was postulated that the dissociation of the sulfoxide adducts occurs under kinetic control (N(2)-loss pathway via a much more energetic transition state). For the sulfide and sulfone adducts, on the other hand, the dissociation process takes place via a thermodynamically controlled process.

Chemical Composition and Antimicrobial Activity of the Essential Oil from Microlicia crenulata

Abstract The chemical compositions of essential oils extracted by hydrodistillation and of volatile substances extracted by HS-SPME from aerial parts of Microlicia crenulata were studied. The antimicrobial activity of the essential oil was investigated. The essential oils of M. crenulata consist of a complex mixture, composed mainly of terpenoid compounds. There is a slight variation in the yield and chemical composition of the essential oils according to the phenological stages of the year. The oil presented moderate inhibitory activity against Pseudomonas aeruginosa, but did not inhibit the growth of Bacillus cereus var. mycoides, Escherichia coli and Staphylococcus aureus. The oil showed moderate antimicrobial activity against Sacharomyces cerevisiae and Aspergillus flavus fungi, weak activity against Aspergillus niger and was not active against species of Candida and Cryptococcus at the highest concentration tested (250 µg/mL). This study is the first to report the composition and antimicrobial properties of the essential oil of M. crenulata.

Atorvastatin as a promising anticryptococcal agent

Cryptococcosis caused by Cryptococcus gattii leads to pneumonia and meningoencephalitis, and has a high mortality rate worldwide due to the inadequacy of available therapy and increasing drug resistance. There is a need to develop effective treatments, and drug repositioning is an interesting alternative to achieve new strategies to treat cryptococcosis. Atorvastatin (ATO), a statin currently used to treat hypercholesterolaemia, was tested in this study as an adjuvant to control infections caused by C. gattii. Several aspects of the effect of ATO on the host and the yeast were evaluated, with particular focus on the association of ATO with fluconazole (FLC), which (i) reduced ergosterol content in the cell membrane and altered properties of the polysaccharide capsule of C. gattii; (ii) increased the production of reactive oxygen species by macrophages; and (iii) reduced yeast phagocytosis and the intracellular proliferation rate. In an animal model, infected mice treated with ATO + FLC showed increased survival, improved clinical condition, and reduced fungal burden in the lungs and brain. This study is the first to perform in vivo tests with ATO + FLC for the treatment of cryptococcosis. The results suggest that ATO may be an important adjuvant for the treatment of cryptococcosis.

Ecology and identification of environmental fungi and metabolic processes involved in the biodeterioration of Brazilian soapstone historical monuments

This study aimed to evaluate the action of organic acids produced by the fungal population associated with the biodeterioration process of the Twelve Prophets of Aleijadinho, a set of soapstone sculptures in Congonhas, state of Minas Gerais, Brazil. For this, samples of fungi were obtained from the surface of each of the 12 outdoor stone sculptures that comprise the set of Prophets. The identification of the colonizing filamentous fungi was performed by classical microbiology and molecular methods. Some species of filamentous fungi‐dependent cultivation were detected, and the presence of species Aspergillus versicolor, Curvularia lunata, Epicoccum nigrum, Penicillium citrinum and Pseudocercospora norchiensis indicated a connection with the excretion of organic acids. The acids produced by each of these fungal species were analysed quantitatively by chromatographic methods, revealing potential biodeterioration by the action of acidic metabolites excreted in the stone.

Biocidal Effect of Gamma Radiation on the Ecology of Filamentous Fungal Populations Associated with Stone Deterioration

This study focused on the identification of the filamentous fungi associated with soapstone samples exposed to outdoor conditions and the biocidal effect of gamma radiations on isolated fungal populations in Minas Gerais State in Brazil. Two soapstone blocks were placed outdoors under tropical environmental conditions for 12 months. A total of 9 filamentous fungal populations were identified on their surfaces, namely Acremomium (cf.) alternatum, Alternaria alternata, Aspergillus fumigatus, Calcarisporium (cf.) arbuscula, Cladosporium cladosporioides, Curvularia lunata, Epicoccum nigrum, Fusarium equiseti and Penicillium citrinum. The gamma radiation assay was then carried out as a test of biocidal action by exposing all fungal populations to the ionizing radiation. The results showed that only the C. cladosporioides species was resistant to this biocidal agent, since it was able to increase its population post exposure. Scanning electron microscopy images identified the microbial colonization on the soapstone blocks and the stone elementar composition was analyzed by energy dispersive X-ray spectrometry. After treatment, there was no structural and aesthetic alteration in the soapstone samples, and evidencing that gamma radiation can be used as a biocidal agent. However, the resistance of the black fungal population indicates caution in the choice of gamma irradiation as biocidal treatment.

Endotoxins in surgical instruments of hip arthroplasty

OBJECTIVE To investigate endotoxins in sterilized surgical instruments used in hip arthroplasties. METHOD A descriptive exploratory study conducted in a public teaching hospital. Six types of surgical instruments were selected, namely: acetabulum rasp, femoral rasp, femoral head remover, chisel box, flexible bone reamer and femoral head test. The selection was based on the analysis of the difficulty in removing bone and blood residues during cleaning. The sample was made up of 60 surgical instruments, which were tested for endotoxins in three different stages. The EndosafeTM Gel-Clot LAL (Limulus Amebocyte Lysate method) was used. RESULT There was consistent gel formation with positive analysis in eight instruments, corresponding to 13.3%, being four femoral rasps and four bone reamers. CONCLUSION Endotoxins in quantity ≥0.125 UE/mL were detected in 13.3% of the instruments tested. OBJETIVO Investigar endotoxinas em instrumentais cirúrgicos esterilizados empregados em artroplastias do quadril. MÉTODO Estudo exploratório, descritivo, desenvolvido em um hospital público de ensino. Foram selecionados seis tipos de instrumentais, a saber: raspa acetabular, raspa femural, saca-cabeça de fêmur, formão box, fresa de fêmur e cabeça de prova de fêmur. A seleção foi feita a partir da análise da dificuldade para a remoção de resíduos de sangue e osso durante a limpeza. A amostra foi constituída por 60 instrumentais cirúrgicos, que foram testados para endotoxinas em três momentos distintos. Foi utilizado o método de gel-clot pelo Limulus Amebócito Lisado (LAL) Endosafe(tm). RESULTADO Houve formação de gel consistente com análise positiva em oito instrumentais, o que corresponde a 13,3%, sendo quatro raspas de fêmur e quatro fresas de fêmur. CONCLUSÃO Foram detectadas endotoxinas em quantidade ≥0,125 UE/mL em 13,3% dos instrumentais testados.OBJETIVO Investigar endotoxinas em instrumentais cirurgicos esterilizados empregados em artroplastias do quadril. METODO Estudo exploratorio, descritivo, desenvolvido em um hospital publico de ensino. Foram selecionados seis tipos de instrumentais, a saber: raspa acetabular, raspa femural, saca-cabeca de femur, formao box, fresa de femur e cabeca de prova de femur. A selecao foi feita a partir da analise da dificuldade para a remocao de residuos de sangue e osso durante a limpeza. A amostra foi constituida por 60 instrumentais cirurgicos, que foram testados para endotoxinas em tres momentos distintos. Foi utilizado o metodo de gel-clot pelo Limulus Amebocito Lisado (LAL) Endosafe(tm). RESULTADO Houve formacao de gel consistente com analise positiva em oito instrumentais, o que corresponde a 13,3%, sendo quatro raspas de femur e quatro fresas de femur. CONCLUSAO Foram detectadas endotoxinas em quantidade ≥0,125 UE/mL em 13,3% dos instrumentais testados.