Efficacy assessment of different time cycles of nebulized hydrogen peroxide against bacterial and yeast biofilms.

BACKGROUND: The prevention of healthcare-associated infections requires continuous effort. In order to achieve better practical results, the control of environmental microbial biofilms with effective disinfection strategies should be addressed. AIM: To test the efficacy of different time cycles of nebulized hydrogen peroxide (H2O2) against bacterial and yeast dry biofilms. METHODS: The efficacies of a standard cycle (SC) and a fast cycle (FC) of nebulized H2O2 were compared. Microbial biofilms were grown on different material coupons. The metabolic activity of biofilms was determined by XTT assay, and the total biomass of biofilms was determined by crystal violet assay. FINDINGS: Regarding the efficacy of nebulized H2O2 against biofilms, the mean reduction in metabolic activity for the SC was 55.2% [standard deviation (SD) 19.4%], compared with 50.4% (SD 17.7%) for the FC. The mean reduction in total biomass for the SC was 45.5% (SD 22.7%), compared with 46.7% (SD 21.7%) for the FC. No significant differences were found between the tested cycles and materials. CONCLUSION: H2O2 nebulization was found to exhibit good efficacy against healthcare-associated microbial dry biofilms. Moreover, similar efficacies were found between the SC and the FC.

Fast-cycle hydrogen peroxide nebulization against frequent healthcare-associated micro-organisms: efficacy assessment.

BACKGROUND: Hydrogen peroxide (H2O2)-based technology is currently used with the aim of controlling microbial contamination in hospital settings. However, the long cycles required result in prolonged room turnover time, thus precluding a wider implementation of the technology. AIM: To assess the efficacy of a shorter cycle of nebulized H2O2 against healthcare-associated micro-organisms, further comparing among multidrug-resistant and multidrug-susceptible strains. METHODS: The efficacy of a standard cycle (1 h) and of a faster cycle (15 min) of a 7% H2O2 nebulized solution was compared against bacteria and yeasts. MDR and MDS strains were inoculated on polyvinyl chloride, stainless steel, linoleum, napa leather, and formica coupons, and their growth ability was compared. FINDINGS: Globally, the mean efficacy of the standard cycle ranged between 82.5% (±17.0) and 95.9% (±8.3), while the efficacy of the fast cycle ranged between 84.4% (±17.0) and 95.7% (±10.5). No statistically significant differences were found for the majority of the tested cycles and materials. For all the tested strains, no differences were found regarding the efficacy of cycles. CONCLUSION: The very high disinfection efficacy of the fast cycle was found to be similar to that of the standard cycle. Moreover, a similar efficacy was also demonstrated when comparing between multidrug-resistant and multidrug-susceptible strains. This study supports a wider implementation of the technology, with the expected advantages of reducing room turnover time, costs, and indirect infection transmission. Further assessment of the efficacy of this faster cycle against other emergent microbial global threats would be highly recommended.

Anti-Candida activity of antimicrobial impregnated central venous catheters.

BACKGROUND: Whenever the rate of central line-associated bloodstream infections (CLABSIs) remains high even after the implementation of preventive strategies, the use of chlorhexidine/silver sulfadiazine (CSS) or minocycline/rifampin (MR)-impregnated central venous catheters (CVCs) is currently recommended. Nevertheless, the efficacy of such CVCs against Candida albicans and other emerging non-albicans spp. has been insufficiently studied. This study aims to compare the activity of CSS and MR-impregnated CVCs against the yeasts most frequently isolated from CLABSIs. METHODS: For biofilm formation assays, type strains and clinical isolates of C. albicans, C. glabrata and C. parapsilosis sensu stricto were used. Segments of standard polyurethane, MR and second-generation CSS-CVCs were tested. The biofilm metabolic activity was measured by a semi-quantitative XTT reduction assay. RESULTS: CSS catheter segments significantly reduced the biofilm metabolic activity by all tested Candida spp., with inhibition ranging from 60% to 100%. The MR catheter segments promoted C. albicans and C. parapsilosis biofilm formation and exhibited an inconspicuous effect against C. glabrata. CONCLUSIONS: Among the recommended antimicrobial CVCs, CSS-CVCs proved to be superior in the inhibition of biofilm formation by the most frequent yeasts causing CLABSIs. Data from this in vitro study may suggest that patients at high risk for invasive candidosis could benefit from the use of CSS-CVCs.

High-touch surfaces: microbial neighbours at hand.

Despite considerable efforts, healthcare-associated infections (HAIs) continue to be globally responsible for serious morbidity, increased costs and prolonged length of stay. Among potentially preventable sources of microbial pathogens causing HAIs, patient care items and environmental surfaces frequently touched play an important role in the chain of transmission. Microorganisms contaminating such high-touch surfaces include Gram-positive and Gram-negative bacteria, viruses, yeasts and parasites, with improved cleaning and disinfection effectively decreasing the rate of HAIs. Manual and automated surface cleaning strategies used in the control of infectious outbreaks are discussed and current trends concerning the prevention of contamination by the use of antimicrobial surfaces are taken into consideration in this manuscript.

Copper and zinc affect the activity of plasma membrane H+-ATPase and thiol content in aquatic fungi.

Aquatic hyphomycetes are the major microbial decomposers of plant litter in streams. We selected three aquatic hyphomycete species with different abilities to tolerate, adsorb and accumulate copper and zinc, and we investigated the effects of these metals on H+-ATPase activity as well as on the levels of thiol (SH)-containing compounds. Before metal exposure, the species isolated from a metal-polluted stream (Heliscus submersus and Flagellospora curta) had higher levels of thiol compounds than the species isolated from a clean stream (Varicosporium elodeae). However, V. elodeae rapidly increased the levels of thiols after metal exposure, emphasizing the importance of these compounds in fungal survival under metal stress. The highest amounts of metals adsorbed to fungal mycelia were found in the most tolerant species to each metal, i.e. in H. submersus exposed to copper and in V. elodeae exposed to zinc. Short-term (10 min) exposure to copper completely inhibited the activity of H+-ATPase of H. submersus and V. elodeae, whilst zinc only led to a similar effect on H. submersus. However, at longer exposure times (8 days) the most metal-tolerant species exhibited increased H+-ATPase activities, suggesting that the plasma membrane proton pump may be involved in the acclimation of aquatic hyphomycetes to metals.

Produção de biomassa aérea, teor e rendimento de extrato das folhas de crajiru [ Arrabidaea chica (Bonpl. ) B. Verl. ] em função de adubação orgânica em Manaus, estado do Amazonas, Brasil / Aerial biomass production, content and yield of crajiru leaf extract [Arrabidaea chica (Bonpl. ) B. Verl. ] as a function of organic fertilizer in Manaus, state of Amazonas, Brazil

RESUMO A espécie Arrabidaea chica pertencente à família Bignoniaceae é também conhecida popularmente como crajiru. É Utilizada tradicionalmente no tratamento de enfermidades da pele, inflamações, infecções, dentre outros. O objetivo deste trabalho foi avaliar a produção de biomassa aérea, teor e rendimento de extrato de crajiru em função de diferentes fontes de adubo orgânico em Manaus, AM. As mudas foram formadas através de estacas e mantidas por 60 dias em casa de vegetação. O experimento foi conduzido em esquema fatorial 5x3 com delineamento em blocos casualizados onde os níveis dos fatores foram as diferentes fontes de adubo orgânico: composto (5,0 kg/m2), esterco de aves (3,0 kg/m2), casca de guaraná (4,0 kg/m2), esterco de gado (4,0 kg/m2) e controle (ausência), e os três morfotipos de crajiru. Obedeceu-se o espaçamento de 1,0x1,0 m entre planta e 2,0 m entre blocos. Após 240 dias foram avaliadas a produção de folhas e caules, relação folha/caule, teor de extratos hexânico concentrado em evaporador rotativo obtido pela fórmula: (massa do extrato/massa da amostra total)x100; e o rendimento de extrato estimado pela equação: (%extrato x massa seca total das folhas)/100. Os dados foram submetidos à análise de variância e as médias ao Teste de Tukey (p<0,05). As fontes de adubo orgânico promoveram melhor desenvolvimento das plantas de, exceto para o morfotipo 1. O esterco de aves proporcionou maior produção de biomassa, teor e rendimento de extratos. Dessa forma, sugere-se que a adubação orgânica propicia maior produção de biomassa, teor e rendimento de extratos de A. chica.

ABSTRACT The Arrabidaea chicaspecies belongs to the Bignoniaceae family and is also popularly known as crajiru. It is traditionally used to treat skin diseases, inflammations and infections. The objective of this study was to evaluate the biomass production, the content and the yield of crajiru extract in face of different sources of organic fertilizer in Manaus, AM. The seedlings were formed by cuttings and kept for 60 days in a greenhouse. The trial was conducted in a 5x3 factorial design with randomized block organization where the factor levels were different sources of organic fertilizer: compound (5.0 kg / m 2), chicken manure (3.0 kg / m 2), bark guarana (4.0 kg / m2), cattle manure (4.0 kg / m 2) and control (absence), and the three morphotypes of crajiru. It was obeyed the spacing between the plants (1,0 x1,0m) and the blocks (2,0m) . After 240 days it were evaluated the production of leaves and stems, the leaf / stem ratio, and the content of hexane extracts concentrated by rotary evaporation obtained by the following formula: (mass of extract / mass of total sample) x100; and the yield estimated by the equation extract: (% extract x total dry mass of leaves) / 100. The data were subjected to analysis of variance and means to the Tukey"s test (p <0.05). The sources of organic fertilizer promoted better development of plants, except for the morphotype 1. The poultry manure provided higher biomass, content and yield of extracts. Thus, it is suggested that the organic fertilizer provides greater biomass production, content and yield of A. chica extracts.

Polyethyleneimine and polyethyleneimine-based nanoparticles: novel bacterial and yeast biofilm inhibitors.

Biofilms are commonly involved in medical device-related infections. The purpose of this study was to determine the antimicrobial and anti-biofilm activity of polyethyleneimine (PEI) and PEI-based nanoparticles (nanoPEI) against Staphylococcus aureus, Staphylococcus epidermidis, Acinetobacter baumannii and Candida albicans (clinical and ATCC strains), and to evaluate their effect upon biofilm formation on polyurethane (PUR)-like catheters. MICs and minimal lethal concentrations of PEI and nanoPEI were determined according to CLSI microdilution reference protocols. For PEI, the MIC value was 195.31 mg l(-1) for all the bacteria and 48.83 mg l(-1) for the yeast strains. For nanoPEI, the MIC value was 1250 mg l(-1) for all the strains except A. baumannii, for which it was 2500 mg l(-1). Biofilm formation was assessed with PUR-like catheter segments and biofilm metabolic activity was quantified by colorimetry with a tetrazolium reduction assay. Plasma membrane integrity and membrane potential were assessed by flow cytometry after staining microbial cells with a membrane-impermeable dye, propidium iodide, and a membrane-potential marker, DiBAC4(3). PEI inhibited growth of all microbial species; higher concentrations of nanoPEI were needed to inhibit growth of all species. Biofilm formation in the presence of anti-bacterial PEI activity was dose-dependent (except for S. epidermidis) and species-related. NanoPEI at 0.5×MIC and MIC significantly reduced the metabolic activity of biofilms of S. aureus, S. epidermidis and A. baumannii, whereas 2×MIC was required in order to inhibit biofilm metabolic activity.

In vivo antibiofilm effect of cerium, chitosan and hamamelitannin against usual agents of catheter-related bloodstream infections.

OBJECTIVES: Catheter-related bloodstream infections (CRBSIs) are common healthcare-associated infections associated with increased morbidity and medical costs. Antiseptic- and antibiotic-coated central venous catheters (CVCs) have been proposed to reduce the incidence of CRBSIs, with variable success. The aim of this study was to determine the in vivo antibiofilm activity of biocompatible and inexpensive compounds, such as cerium nitrate, chitosan and hamamelitannin, against usual agents of CRBSIs. METHODS: The antibiofilm effect of cerium nitrate, chitosan and hamamelitannin was tested against Staphylococcus epidermidis, Staphylococcus aureus, Acinetobacter baumannii and Candida albicans in a mouse foreign body infection model, using polyurethane catheter segments. Biofilm formation was assessed with a crystal violet assay to quantify the total biomass, with a tetrazolium reduction assay to quantify the metabolic activity and with scanning electron microscopy. RESULTS: At subinhibitory concentrations, cerium nitrate significantly reduced biofilm formation by C. albicans, chitosan significantly decreased biofilm formation by S. epidermidis and C. albicans, and hamamelitannin significantly inhibited all bacterial biofilms. DISCUSSION: The in vivo antibiofilm effect of cerium nitrate against C. albicans and of chitosan against C. albicans and S. epidermidis, at subinhibitory concentrations, makes them promising alternatives to coat CVCs. Moreover, the microbicidal effect on a wider range of CVC colonizers was previously reported in vitro for both compounds, at higher concentrations. For all bacterial strains, the highest in vivo antibiofilm efficacy was achieved with hamamelitannin. For A. baumannii, this is the first report of in vivo inhibition.

Cerium, chitosan and hamamelitannin as novel biofilm inhibitors?

OBJECTIVES: The colonization of indwelling medical devices and subsequent biofilm formation represents a global challenge since it promotes the persistence of infection and contributes to antimicrobial resistance. The aim of this study was to determine the antimicrobial activity of cerium, chitosan and hamamelitannin against usual microbial colonizers and to assess their efficacy regarding biofilm formation on polyurethane (PUR)-like catheters. METHODS: The antimicrobial and anti-biofilm effect of cerium nitrate, low molecular weight chitosan (LMWC) and hamamelitannin was tested against Staphylococcus epidermidis, Staphylococcus aureus, Acinetobacter baumannii and Candida albicans strains. Biofilm formation was assessed with PUR-like catheter segments and the metabolic activity was quantified by colorimetry with a tetrazolium reduction assay. RESULTS: Cerium nitrate and LMWC inhibited the microbial growth of all microbial strains tested; hamamelitannin showed no inhibition. Regarding biofilm formation on PUR-like catheters, with subinhibitory concentrations: cerium nitrate significantly inhibited the metabolic activity of C. albicans; LMWC reduced the metabolic activity of S. epidermidis and C. albicans; and hamamelitannin decreased the metabolic activity of all tested bacteria, but not of yeasts. CONCLUSIONS: The microbicidal activity of cerium nitrate and LMWC was clearly demonstrated in this study, as was their fungistatic effect at lower concentrations. Hamamelitannin significantly reduced biofilm metabolic activity of all tested bacteria. These microbial inhibitors may play a promising role regarding different biomedical applications.

Poly (epsilon-caprolactone)/propolis extract: microencapsulation and antibacterial activity evaluation.

Spherical and homogenous microparticles of poly(epsilon-caprolactone) (PCL), containing propolis were prepared by the emulsification-solvent evaporation technique. Using this method of preparation, a solid formulation of propolis, free of ethanol and suitable for manipulation and storage, was obtained from an ethanolic extract of propolis. The incorporation efficiency of propolis in the microparticles was almost 30% and around 60% of the substance was released in 48 h. In vitro propolis microparticles exhibited similar halo zones in the Petri plate test against Streptococcus mutans (GS5) with a 10-fold lower concentration than the free propolis extract showing that the encapsulated propolis in microparticles is more efficient as antibiotic.

In vitro studies on the release of isoniazid incorporated in poly(epsilon-caprolactone).

A polymeric micro- and nanosphere formulation using poly (epsilon-caprolactone) (PCL) to entrap an antituberculosis drug, isoniazid (INH), was developed and characterized. The microspheres were prepared by a solvent evaporation method using ethyl acetate, PCL and INH as the organic phase and water and Tween 40 as the aqueous phase. The nanospheres were prepared by a spontaneous emulsification solvent diffusion method using 40% ethanol in acetone (v/v), PCL and INH as the organic phase and water and Tween 40 as the aqueous phase. After freeze-drying, these systems were characterized by scanning electron microscopy (SEM), particle size analysis, determination of entrapped INH content, in vitro INH release and brine shrimp toxicity bioassay.

Angiotomatose retiniana afetando irmäo e irmä

Os autores fazem uma revisäo das Facomatoses, com especial enfoque para a Doença de Von Hippel-Lindau. Dois casos (irmäo e irmä) säo apresentados

Atropina amiga x atropina inimiga: usos oftalmicos. / Friend atropine x enemy atropine: ophthalmic uses

Muitos casos de doencas oftalmicas vem sendo tratados com o sulfato de atropina; entretanto, existem melhores drogas para acao midriatica e cicloplegica. O presente estudo enumera varias ocasioes onde a atropina nao e necessaria, ou onde ela pode ser substituida por outra droga, ou quando ela nao e indicada em oftalmologia. Ao mesmo tempo, descreve-se o uso apropriado de atropina na pratica oftalmologica