Environmental microbial colistin resistance in an elderly south Brazilian long-term care facility.

Colistin resistance is a global health concern, with antibiotics being the last treatment for Gram-negative bacteria infections. We aimed to identify colistin-resistant enterobacteria on environmental surfaces of a long-term care facility (LTCF) for the elderly in southern Brazil. Samples were collected and screened on MacConkey agar plus colistin, followed by API20E identification and PCR. Two isolates were founded and identified as Klebsiella pneumoniae and Providencia stuartii harboring mcr-1 gene with MICs > 128 µg mL-1 for colistin. This is the first isolation of microorganisms resistant to colistin in the environment of a LTCF for the elderly in south Brazil, urging monitoring programs to reduce environmental contamination by multiresistant microorganisms.

Adsorption for rhodamine b dye and biological activity of nano-porous chitosan from shrimp shells.

The present work aims to evaluate the removal capacity of Rhodamine B dye (RhB) using nano-porous chitosan (NC) from shrimp shells. NC was characterized by XRD, SEM-EDS, N2 porosimetry, zeta potential (ZP), FTIR, DLS, and zero charge point (pHZCP). Compound central rotational design (CCRD) was used to determine the ideal condition and antimicrobial activity was evaluated against different strains. NC showed characteristic of semi-crystalline material with negative charge surface (around - 21.13 mV), and SBET = 1.12 m2 g-1, Vp = 0.0064 cm3 g-1, Dp = 32.09 nm and pHZCP ≈ 7.98. Kinetic adsorption showed the pseudo first-order model had the best fit, with adsorption capacity (q1) between 3.78 and 64.43 mg g-1 and pseudo first-order kinetic constant (k1) between 0.066 and 0.052 min-1. Sips model best described the equilibrium data, with a maximum adsorption capacity of 505.131 mg g-1. Antimicrobial activity was observed at 0.25 mg mL-1 for different strains. Therefore, NC has potential application in the removal of the dye, combining sustainable development associated with nanotechnology.

Silver nanoparticles from residual biomass: Biosynthesis, characterization and antimicrobial activity.

The industrial effluent contaminated with organic pollutants has been causing an increase in the toxicity of the ecosystem, causing a great environmental impact. Thus, the present work aims the green synthesis of silver nanoparticles (AgNPs) from Aloe vera, its characterization and antimicrobial activity against Pseudomonas aeruginosa (ATCC 27853) and Staphylococcus aureus (ATCC 25923). AgNPs were characterized by X-ray diffraction (XRD), Scanning Electronic Microscopy with Energy Dispersive Spectroscopy (SEM-EDS), Zeta Potential (ZP) and N2 porosimetry (BET/BJH method). Antimicrobial activity were carried out by Minimal Inhibitory Concentration (MIC) method. The XRD demonstrated characteristic peaks of AgNPs at 38.29°; 44.55° and 64.81°, and SEM-EDS micrographs showed that AgNPs produced by biomolecules of Aloe vera extract resulted in a weight concentration around 92.59% silver, 7.15% oxygen and 0.26% chlorine. Regarding zeta potential, all samples showed negative electric charge (around -35.3 mV), while N2 porosimetry resulted in a surface specific area of 6.09 m2 g-1, with a volume and diameter pore of 0.032 cm³ g-1 and 33.47, respectively. Antimicrobial activity was observed at 15.62 µg mL-1 and 31.25 µg mL-1 for P. aeruginosa and S. aureus, respectively. Thus, AgNPs can be considered a promising nanoparticle for degradation of organic pollutants in aqueous solution as well as an adjuvant for treatment of microbial infections.

Green Nanoarchitectonics of Silver Nanoparticles for Antimicrobial Activity Against Resistant Pathogens.

Antimicrobial resistance represents a serious concern to public health, being responsible for hospital infections, affecting mainly immunosuppressed patients. Thus, nanotechnology appears as an alternative to solve this problem, through the application of metallic nanoparticles with antimicrobial activity. The present work aims to synthesize and characterize AgNPs from Klebsiella pneumoniae (AgNPs-KP) and Aloe vera extract (AgNPs-AV), evaluating the antimicrobial activity against Klebsiella pneumoniae carbapenemase (KpC) and the cytotoxicity in the L929 cell line. AgNPs were prepared by the biosynthetic method using Klebsiella pneumoniae and were characterized by XRD, FTIR and SEM-EDS. Antimicrobial activity was tested using the MIC and MBC. The cytotoxicity was evaluated by the MTT method and neutral red. The production of ROS and nitrogen RNS tests were performed in the L929 cell line. Thus, it was possible to confirm the production of AgNPs-KP, through morphological, structural and elemental analysis. AgNPs from Klebsiella pneumoniae had potent antimicrobial activity in low concentration against antimicrobial resistant pathogens with MIC 9.76 µg mL-1 and MBC 9.06 µg mL-1. Moreover, AgNPs-KP in concentrations of 10, 30 and 100 µg mL-1 did not show cytotoxic properties for the L929 fibroblast, where only the cytotoxic effect was observed in high concentrations (300 µg mL-1). AgNPs-KP did not produce ROS about the analyzed concentrations and RNS production was only in the highest concentration of 3000 µg mL-1. Therefore, AgNPs biosynthesized by Klebsiella pneumoniae have potential medical applicability as a promising antimicrobial agent, using a simple and low-cost method, correlating nanomedicine as nanostructured materials.

Protective Effect of Indomethacin-loaded Polymeric Nanoparticles Against Oxidative Stress-Induced Cytotoxicity in Human Breast Adenocarcinoma Cell Model / Efeito Protetor de Nanopartículas Poliméricas com Indometacina contra Citotoxicidade Induzida por Estresse Oxidativo em Modelo Celular de Adenocarcinoma de Mama Humano / Efecto Protector de Nanopartículas Poliméricas con Indometacina contra la Citotoxicidad Inducida por Estrés Oxidativo en Modelo de Células de Adenocarcinoma de Mama Humano

Introduction: Anti-inflammatory drugs are being utilized to treat cancer because of its inflammatory microenvironment. Objective: The objective of this study is to investigate the antioxidant potential of indomethacin and its genotoxicity, since free or loaded in polymeric nanocapsules using MCF-7 (human breast cancer) cells as an in vitro model. Method: Development of indomethacin-loaded polyepsilon-caprolactone (PCL) nanocapsules by interfacial deposition method. It is characterized by pH determination by potentiometer, mean diameter and polydispersity index by dynamic light scattering; zeta potential by electrophoretic mobility; encapsulation efficacy by high performance liquid chromatography method; corona effect formation; 2',7'-dichlorofluorescin diacetate (DCFH-DA) method by spectrofluorimetric assay; nitric oxide (NO) determination by spectrophotometric and genotoxicity assay by plasmid DNA cleavage method. Results: The results showed a mild acidic pH (4.78 ± 0.10), sizes around 200 nm and PDI<0.2 with a zeta potential around -20 mV and encapsulation efficiency of 99% (1 mg mL-1), showing a dose-dependent corona formation profile in 24h incubation. Conclusion: DCFH-DA assay showed no production of reactive oxygen species (ROS) while NO determination showed that Ind-OH-NC from 26.7 to 100 µM increased reactive nitrogen species (RNS), demonstrating antioxidant potential against MCF-7 cells. No sample at the concentrations evaluated induced DNA cleavage, being considered a safe treatment

Introdução: Anti-inflamatórios estão sendo empregados para tratamento de câncer por causa do seu ambiente inflamado. Objetivo: Investigar o potencial antioxidante da indometacina e sua genotoxicidade, livre ou carreada em nanocápsulas poliméricas, usando como modelo in vitrocélulas MCF-7 (câncer de mama humano). Método: Desenvolvimento de nanocápsulas de poliepsilon-caprolactona (PCL) por método de deposição interfacial, caracterizada por determinação de pH por potenciômetro; diâmetro médio e índice de polidispersão por espalhamento dinâmico de luz; potencial zeta por mobilidade eletroforética; eficiência de encapsulação por cromatografia líquida de alta eficiência; formação de efeito corona; método de 2',7'-diclorofluoresceína diacetato (DCFH-DA) por ensaio espectrofluorimétrico; determinação de óxido nítrico (NO) por espectrometria e ensaio de genotoxicidade por método de clivagem do DNA plasmidial. Resultados: Os resultados mostraram leve pH ácido (4,78 ± 0,10), tamanhos em torno de 200 nm e PDI<0,2 com potencial zeta em torno de -20 mV e eficiência de encapsulação de 99% (1 mg mL-1), apresentando perfil de formação de corona dose-dependente em 24 horas de incubação. Conclusão: O ensaio DCFH-DA mostrou que não há produção de espécies reativas de oxigênio (ROS), enquanto a determinação de NO mostrou que Ind-OH-NC de 26,7 a 100 µM aumentou as espécies reativas de nitrogênio (RNS), demonstrando potencial antioxidante contra MCF-7. Nenhuma amostra nas concentrações avaliadas induziu clivagem do DNA, sendo considerado um tratamento seguro

Introducción: Se están utilizando antiinflamatorios para tratamiento de cáncer debido a su entorno inflamado. Objetivo: Investigar el potencial antioxidante de la indometacina y su genotoxicidad, libre o acarreada en nanocápsulas poliméricas utilizando como modelo in vitro células MCF-7 (cáncer de mama humano). Método: Desarrollo de nanocápsulas de poli epsilon-caprolactona (PCL) por método de deposición interfacial, caracterizada por determinación de pH por potenciómetro; diámetro medio e índice de polidispersión por esparcimiento dinámico de luz; potencial zeta por movilidad electroforética; eficiencia de encapsulación por cromatografía líquida de alta eficiencia; formación de efecto corona; método de 2',7'-diclorofluoresceína diacetato (DCFH-DA) por ensayo espectrofluorímetro; determinación de óxido nítrico (NO) por espectrometría y ensayo de genotoxicidad por método de clivaje del ADN plasmídico. Resultados: Los resultados mostraron ligero pH ácido (4,78 ± 0,10), tamaños alrededor de 200 nm y PDI<0,2 con potencial zeta alrededor de -20 mV y eficiencia de encapsulación de 99% (1 mg mL-1), presentando perfil de formación de corona dosis-dependiente en 24h de incubación. Conclusión: El ensayo DCFDA mostró que no hay producción de especies reactivas de oxígeno (ROS) mientras que la determinación de NO mostró que Ind-OH-NC de 26,7 a 100 µM aumentó las especies reactivas de nitrógeno (RNS), demostrando potencial antioxidante contra MCF-7. Ninguna muestra en las concentraciones evaluadas indujo clivaje del ADN, siendo considerado un tratamiento seguro

Protective Effect of Indomethacin-loaded Polymeric Nanoparticles Against Oxidative Stress-Induced Cytotoxicity in Human Breast Adenocarcinoma Cell Model / Efeito Protetor de Nanopartículas Poliméricas com Indometacina contra Citotoxicidade Induzida por Estresse Oxidativo em Modelo Celular de Adenocarcinoma de Mama Humano / Efecto Protector de Nanopartículas Poliméricas con Indometacina contra la Citotoxicidad Inducida por Estrés Oxidativo en Modelo de Células de Adenocarcinoma de Mama Humano

Anti-inflammatory drugs are being utilized to treat cancer because of its inflammatory microenvironment. Objective: The objective of this study is to investigate the antioxidant potential of indomethacin and its genotoxicity, since free or loaded in polymeric nanocapsules using MCF-7 (human breast cancer) cells as an in vitro model. Method: Development of indomethacin-loaded polyepsilon-caprolactone (PCL) nanocapsules by interfacial deposition method. It is characterized by pH determination by potentiometer, mean diameter and polydispersity index by dynamic light scattering; zeta potential by electrophoretic mobility; encapsulation efficacy by high performance liquid chromatography method; corona effect formation; 2',7'-dichlorofluorescin diacetate (DCFH-DA) method by spectrofluorimetric assay; nitric oxide (NO) determination by spectrophotometric and genotoxicity assay by plasmid DNA cleavage method. Results: The results showed a mild acidic pH (4.78 ± 0.10), sizes around 200 nm and PDI PDI<0.2 with a zeta potential around -20 mV and encapsulation efficiency of 99% (1 mg mL-1), showing a dose-dependent corona formation profile in 24h incubation. Conclusion: DCFH-DA assay showed no production of reactive oxygen species (ROS) while NO determination showed that Ind-OH-NC from 26.7 to 100 µM increased reactive nitrogen species (RNS), demonstrating antioxidant potential against MCF-7 cells. No sample at the concentrations evaluated induced DNA cleavage, being considered a safe treatment

Introdução: Anti-inflamatórios estão sendo empregados para tratamento de câncer por causa do seu ambiente inflamado. Objetivo: Investigar o potencial antioxidante da indometacina e sua genotoxicidade, livre ou carreada em nanocápsulas poliméricas, usando como modelo in vitro células MCF-7 (câncer de mama humano). Método: Desenvolvimento de nanocápsulas de poliepsilon-caprolactona (PCL) por método de deposição interfacial, caracterizada por determinação de pH por potenciômetro; diâmetro médio e índice de polidispersão por espalhamento dinâmico de luz; potencial zeta por mobilidade eletroforética; eficiência de encapsulação por cromatografia líquida de alta eficiência; formação de efeito corona; método de 2',7'-diclorofluoresceína diacetato (DCFH-DA) por ensaio espectrofluorimétrico; determinação de óxido nítrico (NO) por espectrometria e ensaio de genotoxicidade por método de clivagem do DNA plasmidial. Resultados: Os resultados mostraram leve pH ácido (4,78 ± 0,10), tamanhos em torno de 200 nm e PDI<0,2 com potencial zeta em torno de -20 mV e eficiência de encapsulação de 99% (1 mg mL-1), apresentando perfil de formação de corona dose-dependente em 24 horas de incubação. Conclusão: O ensaio DCFH-DA mostrou que não há produção de espécies reativas de oxigênio (ROS), enquanto a determinação de NO mostrou que Ind-OH-NC de 26,7 a 100 µM aumentou as espécies reativas de nitrogênio (RNS), demonstrando potencial antioxidante contra MCF-7. Nenhuma amostra nas concentrações avaliadas induziu clivagem do DNA, sendo considerado um tratamento seguro

Introducción: Se están utilizando antiinflamatorios para tratamiento de cáncer debido a su entorno inflamado. Objetivo: Investigar el potencial antioxidante de la indometacina y su genotoxicidad, libre o acarreada en nanocápsulas poliméricas utilizando como modelo in vitro células MCF7 (cáncer de mama humano). Método: Desarrollo de nanocápsulas de poli epsilon-caprolactona (PCL) por método de deposición interfacial, caracterizada por determinación de pH por potenciómetro; diámetro medio e índice de polidispersión por esparcimiento dinámico de luz; potencial zeta por movilidad electroforética; eficiencia de encapsulación por cromatografía líquida de alta eficiencia; formación de efecto corona; método de 2',7'-diclorofluoresceína diacetato (DCFH-DA) por ensayo espectrofluorímetro; determinación de óxido nítrico (NO) por espectrometría y ensayo de genotoxicidad por método de clivaje del ADN plasmídico. Resultados: Los resultados mostraron ligero pH ácido (4,78 ± 0,10), tamaños alrededor de 200 nm y PDI<0,2 con potencial zeta alrededor de -20 mV y eficiencia de encapsulación de 99% (1 mg mL-1), presentando perfil de formación de corona dosis-dependiente en 24h de incubación. Conclusión: El ensayo DCFDA mostró que no hay producción de especies reactivas de oxígeno (ROS) mientras que la determinación de NO mostró que Ind-OH-NC de 26,7 a 100 µM aumentó las especies reactivas de nitrógeno (RNS), demostrando potencial antioxidante contra MCF-7. Ninguna muestra en las concentraciones evaluadas indujo clivaje del ADN, siendo considerado un tratamiento seguro

Iron oxide nanocatalyst with titanium and silver nanoparticles: Synthesis, characterization and photocatalytic activity on the degradation of Rhodamine B dye.

Nowadays, there is a growing concern about the environmental impacts of colored wastewater. Thus, the present work aims the synthesis, characterization and determination of photocatalytic activity of iron oxide (Fe2O3) nanocatalyst, evaluating the effect of hybridization with titanium (TiNPs-Fe2O3) and silver (AgNPs-Fe2O3) nanoparticles, on the degradation of Rhodamine B dye (RhB). Nanocatalysts were characterized by XRD, SEM, TEM, FTIR, N2 porosimetry (BET/BJH method), zeta potential and DRS. Photocatalytic tests were performed in a slurry reactor, with the nanocatalyst in suspension, using RhB as a target molecule, under ultraviolet (UV) and visible radiation. Therefore, the photocatalytic activity of the nanocatalysts (non-doped and hybridized) was evaluated in these ideal conditions, where the AgNPs-Fe2O3 sample showed the best photocatalytic activity with a degradation of 94.1% (k = 0.0222 min-1, under UV) and 58.36% (k = 0.007 min-1, under visible), while under the same conditions, the TiO2-P25 commercial catalyst showed a degradation of 61.5% (k = 0.0078 min-1) and 44.5% (k = 0.0044 min-1), respectively. According with the ideal conditions determined, reusability of the AgNPs-Fe2O3 nanocatalyst was measured, showing a short reduction (about 8%) of its photocatalytic activity after 5 cycles. Thus, the Fe2O3 nanocatalyst can be considered a promising catalyst in the heterogeneous photocatalysis for application in the degradation of organic dyes in aqueous solution.

Virulence characteristics and antimicrobial resistance of Aeromonas veronii biovar sobria 312M, a clinical isolate.

Aeromonas are bacteria widely distributed in the environment, and some species are able to cause infections in humans, of which diarrhea is the most common. The objective of this study was to evaluate the presence of virulence and antimicrobial resistance associated characteristics in A. veronii biovar sobria strain 312M isolated from diarrheal stools. For this, the genome sequencing and phenotypical tests were performed. The draft genome annotation revealed several complete pathways associated with carbon metabolism and a mucin-desulfating sulfatase which may contribute to intestine colonization, and a large number of virulence-associated genes encoding structures associated with adhesion, toxins, and secretion systems. The strain exhibited swimming and swarming motility, biofilm formation, and hemolytic activity. It was resistant to ampicillin, ampicillin/sulbactam, and amoxicillin-clavulanic acid. Although a cphA gene encoding a narrow-spectrum carbapenase was identified in the strain genome, no carbapenemase activity was detected in the antimicrobial susceptibility test. When compared with other A. veronii with complete genomes, the main differences in virulence characteristics are related to lateral flagella and type III and VI secretion systems; the antimicrobial resistance spectrum also varied among strains. The results indicated that A. veronii biovar sobria 312M presents high virulence potential and resistance to limited classes of antimicrobials.

Prevalência de resistência constitutiva e induzível à clindamicina em cocos Gram positivos isolados de pacientes hospitalizados em Santa Maria, RS / Prevalence of clindamycin constitutive and inducible resistance in Gram positive cocci isolated from hospitalized patients in Santa Maria, RS

O objetivo deste estudo foi determinar a prevalência de resistência constitutiva e induzível à clindamicina em pacientes hospitalizados . Foram analisados 63 isolados de diversos sítios infecciosos de pacientes internados em um hospital privado de Santa Maria - RS, Brasil. Para determinação dos mecanismos de resistência foi utilizado o método de difusão em disco (D-teste). Foi verificado que três cepas de Staphylococcus aureus (4,8%) apresentaram-se positivas no D-teste, ou seja, exibiram resistência induzível à clindamicina (MLSBi), possivelmente pela presença do gene em (A), em microrganismos dessa espécie. Ademais, foi observado a presença de resistência constitutiva (MLSBc)em 22 amostras, caracterizando, possivelmente, a presença do gene em (B), em Streptococcus sp e em (C), em Staphylococcus sp. A prevalência do mecanismo de resistência, mediado por bomba de efluxo, em 19 amostras foi caracterizada, provavelmente pela presença do gene mrsA. A introdução de mudanças, na rotina do laboratório, através da inclusão do D-teste deve ser encorajada. A pesquisa desses mecanismos de resistência são de elevada importância na escolha e eficácia terapêutica, pois representam, na prática, uma maior segurança para os pacientes e evitam a troca desnecessária de medicação e, consequentemente, a falha terapêutica.

A prospective study on Aeromonas in outpatients with diarrhea in the central region of Rio Grande do Sul State

Aeromonas spp. were identified in five (2,7%) of 182 diarrheal stool cultures, A. caviae was predominant, resistant mainly to ampicillin and cephalotin. This is the first study showing the presence of Aeromonas spp. in diarrheal stools of outpatients in the central region of Rio Grande do Sul State, Brazil.

A prospective study on Aeromonas in outpatients with diarrhea in the central region of Rio Grande do Sul State.

Aeromonas spp. were identified in five (2,7%) of 182 diarrheal stool cultures, A. caviae was predominant, resistant mainly to ampicillin and cephalotin. This is the first study showing the presence of Aeromonas spp. in diarrheal stools of outpatients in the central region of Rio Grande do Sul State, Brazil.

Prevalência de bacilos Gram-negativos não fermentadores de pacientes internados em Porto Alegre-RS / Prevalence of non-fermenting Gram-negative bacilli among inpatients from Porto Alegre-RS

INTRODUÇÃO: Os bacilos Gram-negativos não fermentadores (BGNNF) são frequentemente associados às infecções hospitalares. Além da alta incidência, esses microrganismos possuem resistência a diversos antimicrobianos. OBJETIVO: Analisar a prevalência e o perfil de resistência de BGNNF. MÉTODOS: Foram analisados 14.971 laudos de pacientes em um hospital privado de Porto Alegre-RS, no período de maio de 2006 a março de 2008, sem distinção de sexo e idade. RESULTADOS E CONCLUSÃO: Foram isoladas 326 amostras de BGNNF. As espécies mais prevalentes foram: Pseudomonas aeruginosa (65,03 por cento), Acinetobacter baumannii (16,56 por cento) e Stenotrophomonas maltophilia (9,5 por cento). Outras espécies apresentaram índices inferiores a 5 por cento. Os microrganismos foram isolados de diversos sítios infecciosos. Os materiais biológicos que apresentaram maior positividade para esses microrganismos foram o aspirado traqueal (38,34 por cento), o escarro (18,71 por cento) e a urina (15,95 por cento). A resistência bacteriana mostrou-se mais expressiva a tetraciclinas (89,57 por cento) e sulfametoxazol/trimetoprima (79,75 por cento). Os antimicrobianos mais ativos foram polimixina B, com 100 por cento de sensibilidade, e piperaciclina/tazobactam, com 75,2 por cento de sensibilidade.

INTRODUCTION: The non-fermenting Gram-negative bacilli (NFGNB) have been widely associated with nosocomial infections. Not only are these microorganisms highly prevalent but they are also highly resistant to NFGNB. OBJECTIVE: To assess the prevalence and resistance profile of non-fermenting Gram-negative bacilli. METHODS: 14.971 patient reports from a private hospital in Porto Alegre, Rio Grande do Sul, from May/2006 to March/2008 were analyzed. RESULTS AND CONCLUSION: Three hundred twenty-six samples of non-fermenting Gram-negative bacilli were isolated. The most prevalent species were Pseudomonas aeruginosa (65.03 percent), Acinetobacter baumannii (16.56 percent), and Stenotrophomonas maltophilia (9.5 percent). Other species showed rates lower than 5 percent. The microorganisms were isolated from several infectious sites and the biological materials that showed higher positivity were the following: tracheal aspirate (38.34 percent), spittle (18.71 percent) and urine (15.95 percent). Bacterial resistance was higher with tetracyclines (89.57 percent) and sulfamethoxazole/trimethoprim (79.75 percent). The most active antimicrobials were polymyxin B and piperacillin/tazobactam with 100 percent and 75.2 percent sensibility, respectively.