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1.
Chemosphere ; 242: 125310, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896192

RESUMO

The bacterial composition of biofilms in drinking water distribution systems is significantly impacted by the disinfection regime and substrate material. However, studies that have addressed the changes in the biofilm community during the early stage of formation (less than 10 weeks) were not yet adequate. Here, we explore the effects of the substrate materials (cast iron, stainless steel, copper, polyvinyl chloride, and high density polyethylene) and different disinfectants (chlorine and chloramine) on the community composition and function of young biofilm by using 16S rDNA sequencing. The results showed that Alphaproteobacteria (39.14%-80.87%) and Actinobacteria (5.90%-40.03%) were the dominant classes in chlorine-disinfection samples, while Alphaproteobacteria (17.46%-74.18%) and Betaproteobacteria (3.79%-68.50%) became dominant in a chloraminated group. The infrequently discussed genus Phreatobacter became predominant in the chlorinated samples, but it was inhibited by chloramine and copper ions. The key driver of the community composition was indicated as different disinfectants according to principle coordination analysis (PCoA) and Permutational multivariate analysis of variance (Adonis test), and the bacterial community changed significantly over time. Communities of biofilms grown on cast iron showed a great distance from the other materials according to Bray-Curtis dissimilarity, and they had a unique dominant genus, Dechloromonas. A metagenomics prediction based on 16S rDNA was used to detect the functional pathways of antibiotic biosynthesis and beta-lactam resistance, and it revealed that several pathways were significantly different in terms of their chlorinated and chloraminated groups.


Assuntos
Biofilmes/efeitos dos fármacos , Cloraminas/farmacologia , Cloro/farmacologia , Desinfetantes/farmacologia , Água Potável/microbiologia , Microbiota/efeitos dos fármacos , Materiais de Construção/microbiologia , Desinfecção/métodos , Água Potável/química , Ferro , Microbiota/genética , RNA Ribossômico 16S/genética , Aço Inoxidável , Microbiologia da Água/normas
2.
Chemosphere ; 238: 124526, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31466002

RESUMO

In this paper, for the first time, we show in chloraminated systems, the chloramine decaying proteins (CDP) play an important role in bulk water and biomass (biofilm) in resisting disinfectant. Extracellular polymeric substances in biofilm/biomass are known to protect microbes from disinfectants and toxic materials, but the exact mechanism(s) is/are not known. Starting with the seed from a nitrifying chloraminated reactor, two 5 L reactors were fed intermittently with either chloramine or ammonia containing nutrient solution. The degree of nitrification increased with time in both reactors despite an increase in soluble CDP in the chloraminated reactor, while soluble CDP decreased in the ammoniated one. The suspended biomass collected after eight months of operation from chloraminated reactor contained CDP and responded to short-term chloramine stress (1.5 h with initial 1.5 mg-Cl2·L-1) by the additional production of soluble CDP. The suspended biomass from ammoniated reactor neither contained CDP nor produced soluble CDP as a stress response. The production, release and accumulation of CDP in biomass (biofilm) could be one of several mechanisms microbes use to defend against disinfectants (stress). The new understanding will pave the way for better disinfection management and better design of experiments.


Assuntos
Biofilmes , Biomassa , Reatores Biológicos/microbiologia , Cloraminas/metabolismo , Cloraminas/farmacologia , Proteínas/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Amônia/metabolismo , Biofilmes/efeitos dos fármacos , Desinfetantes/farmacologia , Nitrificação
3.
Ecotoxicol Environ Saf ; 187: 109812, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31669574

RESUMO

Marine biofouling represents a global economic and ecological challenge. Some marine organisms produce bioactive metabolites, such as steroids, that inhibit the settlement and growth of fouling organisms. The aim of this work was to explore bile acids as a new scaffold with antifouling (AF) activity by using chemical synthesis to produce a series of bile acid derivatives with optimized AF performance and understand their structure-activity relationships. Seven bile acid derivatives were successfully synthesized in moderate to high yields, and their structures were elucidated through spectroscopic methods. Their AF activities were tested against both macro- and microfouling communities. The most potent bile acid against the settlement of Mytilus galloprovincialis larvae was the methyl ester derivative of cholic acid (10), which showed an EC50 of 3.7 µM and an LC50/EC50 > 50 (LC50 > 200 µM) in AF effectiveness vs toxicity studies. Two derivatives of deoxycholic acid (5 and 7) potently inhibited the growth of biofilm-forming marine bacteria with EC50 values < 10 µM, and five bile acids (1, 5, and 7-9) potently inhibited the growth of diatoms, showing EC50 values between 3 and 10 µM. Promising AF profiles were achieved with some of the synthesized bile acids by combining antimacrofouling and antimicrofouling activities. Initial studies on the incorporation of one of these promising bile acid derivatives in polymeric coatings, such as a marine paint, demonstrated the ability of these compounds to generate coatings with antimacrofouling activity.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Ácidos e Sais Biliares/farmacologia , Incrustação Biológica/prevenção & controle , Desinfetantes/farmacologia , Pintura , Animais , Organismos Aquáticos/crescimento & desenvolvimento , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Ácidos e Sais Biliares/síntese química , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Desinfetantes/síntese química , Microalgas/efeitos dos fármacos , Microalgas/crescimento & desenvolvimento , Mytilus/efeitos dos fármacos , Poliuretanos/química , Silicones/química
4.
Artigo em Inglês | MEDLINE | ID: mdl-31540503

RESUMO

BACKGROUND: The effectiveness of ready-to-use disinfectant wipes was previously assessed in standardized suspension tests, which were inadequate because they ignored that the wipes are rubbed against a surface. Thus, we assessed the effectiveness of commercially available disinfectant wipes impregnated with an alcoholic solution according to the 16615 standard, which includes a test with mechanical action. METHODS: According to the EN 16615 standard, under clean conditions, four squares (5cm x 5 cm), placed next to one another, were marked on a test surface. Enterococcus hirae, Pseudomonas aeruginosa, and Staphylococcus aureus were inoculated on the leftmost square, and a wipe impregnated with an alcoholic solution was placed to the left of that square. Then, the wipe was pressed with a 2.5 kg weight and moved to the right and back to the left. After contact times of 1, 5, 10, or 15 minutes, we measured the reduction in bacterial load. RESULTS: Alcohol-based ready-to-use commercial wipes did not show sufficient bactericidal activity at the contact times of 1, 5, 10 and 15 minutes. Wipes containing propan-1-ol and a mixture of propan-1-ol and propan-2-ol were active against Pseudomonas aeruginosa at the contact times of 1 minute and 15 minutes. None of the examined wipes were active against Enterococcus hirae or Staphylococcus aureus. CONCLUSION: Bactericidal parameters of ready-to-use disinfectant wipes should be determined in surface tests, in addition to suspension tests, because suspension tests do not simulate the conditions under which disinfectant wipes are used in practice.


Assuntos
1-Propanol/farmacologia , Desinfetantes/farmacologia , 1-Propanol/normas , Antibacterianos , Carga Bacteriana , Técnicas Bacteriológicas , Desinfetantes/normas , Desinfecção , Relação Dose-Resposta a Droga , Streptococcus faecium ATCC 9790/efeitos dos fármacos , Humanos , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Fatores de Tempo
5.
J Endod ; 45(11): 1371-1377, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31542283

RESUMO

INTRODUCTION: Curcumin incorporation into polymeric fibers was tested for its antimicrobial properties and potential use in root canal disinfection. METHODS: Curcumin-modified fibers were processed via electrospinning and tested against a 7-day old established Actinomyces naeslundii biofilm. The medicaments tested were as follows: curcumin-modified fibers at 2.5 and 5.0 mg/mL, curcumin-based irrigant at 2.5 and 5.0 mg/mL, saline solution (negative control), and the following positive controls: 2% chlorhexidine, 1% sodium hypochlorite, and triple antibiotic paste (TAP, 1 mg/mL). All medicaments, except for the positive controls, were allocated according to the light exposure protocol (ie, photoactivation with a light-emitting diode every 30 seconds for 4 minutes or without photoactivation). After treatment, the medicaments were removed, and 1 mL saline solution was added; the biofilm was scraped from the well and used to prepare a 1:2000 dilution. Spiral plating was performed using anaerobic blood agar plates. After 24 hours, colony-forming units (colony-forming units/mL, n = 11/group) were counted to determine the antimicrobial effects. RESULTS: Data exhibited significant antimicrobial effects on the positive control groups followed by the curcumin irrigants and, lastly, the photoactivated curcumin-modified fibers. There was a significant reduction of viable bacteria in curcumin-based irrigants, which was greater than the TAP-treated group. Curcumin-free fibers, saline, and the nonphotoactivated curcumin-modified fibers did not display antimicrobial activity. CONCLUSIONS: Curcumin seems to be a potential alternative to TAP when controlling infection, but it requires a minimal concentration (2.5 mg/mL) to be effective. Photoactivation of curcumin-based medicaments seems to be essential to obtain greater antibiofilm activity.


Assuntos
Curcumina , Desinfetantes , Tratamento do Canal Radicular , Actinomyces/efeitos dos fármacos , Biofilmes , Curcumina/farmacocinética , Curcumina/farmacologia , Cavidade Pulpar , Desinfetantes/farmacocinética , Desinfetantes/farmacologia , Desinfecção , Liberação Controlada de Fármacos , Enterococcus faecalis , Irrigantes do Canal Radicular , Hipoclorito de Sódio
6.
Biocontrol Sci ; 24(3): 155-160, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31527346

RESUMO

Ozonated water (OW) is presently used as a chemical disinfectant in many fields, due to its versatile antimicrobial properties. As ozone rapidly decomposes to oxygen, especially in the presence of organic matter, it is important to estimate the authentic antimicrobial activity of OW in the presence of contaminants. However, the effect of contaminants on the antimicrobial activity of OW has not been fully investigated. To address this, we evaluated the effect of protein contaminants on the antimicrobial activity of OW. The survival rate of each tested microorganism excluding Bacillus subtilis spores was reduced to less than 0.1%, when the microorganism suspension was exposed to 9.1 ppm of OW for 15 s in the presence of 0.0045% protein. Our study therefore suggests that approximately 10 ppm of OW can reduce the survival rates of almost all microorganisms in the presence of proteins.


Assuntos
Bacillus subtilis/efeitos dos fármacos , Desinfetantes/farmacologia , Desinfecção/métodos , Ozônio/farmacologia , Proteínas/metabolismo , Poluentes Químicos da Água/metabolismo , Água/química , Viabilidade Microbiana/efeitos dos fármacos
7.
Int J Food Microbiol ; 309: 108328, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31518953

RESUMO

Ultrasound (US) has a high capacity to increase food safety. Although high and/or moderate temperature in combination with US has been studied, the knowledge about cooling/low temperatures as well as its combined effect with chemical preservation methods is scarce. Therefore, the aim of this study was to describe the inactivation of Staphylococcus spp. (SA) present in the natural microbiota of sliced Brazilian dry-cured loin (Socol, BDL) using US (40 kHz and 5.40 W/g) at 1.6-17.9 kJ/g, temperature (T) between 6.4 and 73.6 °C and peracetic acid (PA) between 5.5 and 274.5 mg/L employing the Central Composite Rotatable Design. The model fully describes how the combination of US, T, and PA affects SA inactivation. In BDL, an increase in US acoustic energy density (kJ/g) allows the reduction of T necessary to inactivate SA because of the occurrence of synergistic effect. However, US applied at low T was inefficient. On the other hand, PA was more efficient at low T, since high T degraded this compound at different rates according to the holding T. Therefore, the data indicates a relation between the technologies used in the combined decontamination of sliced BDL improving dry-cured meat safety.


Assuntos
Descontaminação/métodos , Desinfetantes/farmacologia , Conservação de Alimentos/métodos , Carne/microbiologia , Ácido Peracético/farmacologia , Staphylococcus/efeitos dos fármacos , Ondas Ultrassônicas , Brasil , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Inocuidade dos Alimentos/métodos , Staphylococcus/classificação , Staphylococcus/isolamento & purificação , Temperatura Ambiente
8.
BMC Vet Res ; 15(1): 310, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31477099

RESUMO

BACKGROUND: Farm disinfectants are widely used in primary production, but questions have been raised if their use can select for antimicrobial resistance. The present study examined the use of disinfectants in poultry and pig husbandry and its contribution to the antibiotic and disinfectant susceptibility of Escherichia coli (E. coli) strains obtained after cleaning and disinfection. On those field isolates antibiotic susceptibility was monitored and susceptibility to commonly used active components of farm disinfectants (i.e. glutaraldehyde, benzalkoniumchloride, formaldehyde, and a formulation of peracetic acid and hydrogen peroxide) was tested. RESULTS: This study showed a high resistance prevalence (> 50%) for ampicillin, sulfamethoxazole, trimethoprim and tetracycline for both production animal categories, while for ciprofloxacin only a high resistance prevalence was found in broiler houses. Disinfectant susceptibility results were homogenously distributed within a very small concentration range. Furthermore, all E. coli strains were susceptible to in-use concentrations of formaldehyde, benzalkoniumchloride and a formulation of peracetic acid and hydrogen peroxide, indicating that the practical use of disinfectants did not select for disinfectant resistance. Moreover, the results showed no indications for the selection of antibiotic resistant bacteria through the use of disinfectants in agricultural environments. CONCLUSION: Our study suggests that the proper use of disinfectants in agricultural environments does not promote antibiotic resistance nor reduce E. coli disinfectant susceptibility.


Assuntos
Antibacterianos/farmacologia , Galinhas/microbiologia , Desinfetantes/farmacologia , Farmacorresistência Bacteriana , Escherichia coli/efeitos dos fármacos , Suínos/microbiologia , Criação de Animais Domésticos , Animais , Coleta de Dados , Desinfetantes/administração & dosagem , Testes de Sensibilidade Microbiana , Inquéritos e Questionários
9.
Environ Sci Pollut Res Int ; 26(27): 28352-28360, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31372954

RESUMO

The emergence of antibiotic resistance genes (ARGs) in microbes can be largely attributed to the abuse and misuse of antibiotics and biocides. Quaternary ammonium compounds (QACs) have been used worldwide as common disinfectants and detergents; however, their potential impact on the spread and diffusion of ARGs is still unknown. In this study, we detected the QAC resistance gene (qacEΔ1), the 1 integron gene (intI1), and 12 ARGs (sul1, sul2, cfr, cml, fexA, tetA, tetG, tetQ, tetX, ermB, blaTEM, and dfrA1) in 48 water samples from three watersheds by quantitative PCR (qPCR). We investigated the evolution of bacterial antibiotic resistance under QAC and antibiotic environmental pressures by long-term continuous culture. In addition, five QACs were selected to investigate the effect of QAC on the efficiency of conjugation transfer. The changes in bacterial cell membrane and production of reactive oxygen species (ROS) were detected by flow cytometry, revealing the mechanism by which QAC affects the spread of antibiotic resistance. Our results showed that the QAC resistance gene was ubiquitous in watersheds and it had significant correlation with intI1 and seven ARGs (r = 0.999, p < 0.01). QACs could increase the resistance of bacteria to multiple antibiotics. Furthermore, all five QACs promoted the conjugation transfer of the RP4 plasmid; the optimal concentration of QACs was about 10-1-10-2 mg/L and their transfer efficiencies were between 1.33 × 10-6 and 8.87 × 10-5. QACs enhanced membrane permeability of bacterial cells and stimulated bacteria to produce ROS, which potentially promoted the transfer of plasmids between bacteria. In conclusion, this study demonstrated that QACs may facilitate the evolution and gene transfer of antibiotic resistance gene among microbiome.


Assuntos
Desinfetantes/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Compostos de Amônio Quaternário/farmacologia , Bactérias/genética , Farmacorresistência Bacteriana/genética , Genes Bacterianos , Integrons , Compostos de Amônio Quaternário/química
10.
Molecules ; 24(17)2019 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-31450724

RESUMO

The highly prescribed antidepressant, citalopram, as one of newly emerging pollutants, has been frequently detected in the aquatic environment. Citalopram oxidation was examined during sodium hypochlorite (NaOCl) and chlorine dioxide (ClO2) chlorination processes since conventional wastewater treatment plants cannot remove citalopram effectively. Citalopram has been demonstrated to form N-nitrosodimethylamine (NDMA) during chlorination in our previous study. Further investigation on NDMA formation kinetics was conducted in the present study. Influences of operational variables (disinfectant dose, pH value) and water matrix on citalopram degradation, as well as NDMA generation, were evaluated. The results indicated high reactivity of citalopram with NaOCl and ClO2. NDMA formation included two stages during CIT oxidation, which were linear related with reaction time. NaOCl was more beneficial to remove CIT, but it caused more NDMA formation. Increasing disinfectant dosage promoted citalopram removal and NDMA formation. However, no consistent correlation was found between citalopram removal and pH. Contrary to the situation of citalopram removal, NDMA generation was enhanced when citalopram was present in actual water matrices, especially in secondary effluent. DMA, as an intermediate of citalopram chlorination, contributed to NDMA formation, but not the only way.


Assuntos
Compostos Clorados/química , Citalopram/química , Oxirredução , Óxidos/química , Hipoclorito de Sódio/química , Dimetilnitrosamina/química , Desinfetantes/farmacologia , Halogenação , Concentração de Íons de Hidrogênio , Cinética , Estrutura Molecular , Oxirredução/efeitos dos fármacos , Água/química
11.
Food Microbiol ; 84: 103260, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31421758

RESUMO

This study was conducted to investigate the antibacterial activity of the noni fruit extract (NFE) against Listeria monocytogenes (ATCC, 19111 and 19115) and assess its applicability for the washing of fresh-cut produce. Based on the results of the disc diffusion test, L. monocytogenes (ATCC, 19111 and 19115) was susceptible to the activity of NFE than other pathogens studied. Additionally, results of the time-kill assay indicated that NFE at a concentration of 0.5-0.7% effectively killed L. monocytogenes within 7 h. Furthermore, analysis of the intracellular components such as nucleic acids and proteins released from the bacterial cells and their SEM imaging revealed that NFE could increase the membrane permeability of cells resulting in their death. Compared to their unwashed samples, washing of romaine lettuce, spinach, and kale with 0.5% NFE gave a reduction of 1.47, 2.28, and 3.38 log CFU/g, respectively against L. monocytogenes (ATCC, 19111 and 19115), which is significantly different to that of NaOCl. A significant correlation was observed between the antibacterial effect induced due to NFE washing with the surface roughness of the fresh-cut produce than its surface hydrophobicity. Moreover, washing with NFE was not found to affect the color of the samples. These results indicated that NFE demonstrates good antibacterial activity against L. monocytogenes and can be used as a natural sanitizer to ensure the microbiological safety of fresh-cut produce.


Assuntos
Antibacterianos/farmacologia , Desinfetantes/farmacologia , Frutas/química , Listeria monocytogenes/efeitos dos fármacos , Morinda/química , Extratos Vegetais/farmacologia , Contagem de Colônia Microbiana , Manipulação de Alimentos/métodos , Microbiologia de Alimentos/métodos , Alface/microbiologia , Escopoletina/farmacologia , Spinacia oleracea/microbiologia
12.
Food Microbiol ; 84: 103272, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31421761

RESUMO

One of the most important transmission routes of foodborne pathogens is through contaminated food contact surfaces. In this study, we investigated the survival and inactivation of Salmonella enterica serovar Typhimurium on frequently used food contact surfaces in household settings, including plastic cutting board (CB), formica laminate (LA), and stainless steel (SS) surfaces. S. Typhimurium at log (6 h), stationary (24 h), or long-term stationary (LTS) (14 days) phases were evaluated. Results showed that, at medium and high microbial loads, LTS phase cells had significantly higher survivor population compared to log and stationary phase cells at 24 h after inoculation (p < 0.05). Disinfection study showed that LTS phase cells were very resilient to sodium hypochlorite when the initial microbial load was high with disinfection efficacy ranging from 26 to 35%. Scanning electron microscopy of these surfaces at 24 h after inoculation with a high microbial load revealed an early biofilm structure.


Assuntos
Desinfetantes/farmacologia , Viabilidade Microbiana , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/fisiologia , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/fisiologia , Hipoclorito de Sódio/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Contagem de Colônia Microbiana , Desinfecção/métodos , Microbiologia de Alimentos
13.
Food Microbiol ; 84: 103226, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31421764

RESUMO

Atmospheric cold plasma (ACP) is an effective method for microbiological decontamination. This study evaluated an alternative water-based decontamination approach for inactivation of bacterial population from fresh produce and in the wash water generated from fresh produce washing. The study characterised ACP inactivation of attached Listeria innocua and Pseudomonas fluorescens inoculated on lettuce in comparison to chlorine treatment. P. fluorescens was sensitive to ACP treatment and was reduced below detection limit within 3 min of treatment. L. innocua population was reduced by ∼2.4 Log10 CFU/g after 5 min of treatment; showing similar inactivation efficacy to chlorine treatment. The microbial load in wash water was continuously decreased and was below detection limits after 10 min of ACP treatment. Micro-bubbling along with agitation assisted the bacterial detachment and distribution of reactive species, thus increasing bacterial inactivation efficacy from fresh produce and wash water. A shift in pH of plasma functionalised water was observed along with high concentration of nitrate and ozone with a relative amount of nitrites which increased with plasma exposure time. Further, L. innocua treated at different independent pH conditions showed minimal or no effect of pH on ACP bacterial inactivation efficacy. Aqueous ACP treatment poses a promising alternative for decontamination of fresh produce and the associated wash-waters which could be applied in the food industry to replace continuous chlorine dosing of process waters.


Assuntos
Cloro/farmacologia , Desinfetantes/farmacologia , Microbiologia de Alimentos/métodos , Alface/microbiologia , Gases em Plasma , Aderência Bacteriana/efeitos dos fármacos , Contagem de Colônia Microbiana , Descontaminação/métodos , Contaminação de Alimentos/análise , Manipulação de Alimentos , Alface/efeitos dos fármacos , Listeria monocytogenes/efeitos dos fármacos , Pseudomonas fluorescens/efeitos dos fármacos , Água/análise
14.
Lett Appl Microbiol ; 69(4): 302-309, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31436888

RESUMO

Five tungsten carbide nanoparticle preparations (denoted WC1-WC5) were investigated for broad spectrum virucidal activity against four recommended model viruses. These are modified vaccinia virus Ankara (MVA), human adenovirus type 5 (HAdV-5), poliovirus type 1 (PV-1) and murine norovirus (MNV). All virucidal tests were performed two to five times using the quantitative suspension test, which is a highly standardized test method to evaluate the virucidal efficacy of disinfectants in accordance with the European norm EN 14476+A1 and the German DVV/RKI guidelines. Quantitative detection of viruses was conducted by endpoint titration and quantitative real-time PCR. Results showed that three of the five tested compounds (WC1-WC3) were able to reduce the infectivity of all model viruses by at least four log10 of tissue culture infective dose 50% per ml after 15 min, whereas the other two compounds exhibited only limited efficacy (WC4) or showed cytotoxicity (WC5). Virucidal activity of nanoparticles increased with incubation time and a dose-effect curve showed dependence of virucidal activity with particle concentration. Whereas WC1-WC4 showed little cytotoxicity, WC5 which was doped with copper exhibited a significant cytotoxic effect. These findings propose tungsten carbide nanoparticles to be very promising in terms of new disinfection techniques. SIGNIFICANCE AND IMPACT OF THE STUDY: The present study investigates the virucidal activity of tungsten carbide nanoparticles using the quantitative suspension test in accordance with the European norm EN 14476+A1 and the German DVV/RKI guidelines. Due to highly standardized assay conditions, results of this test are considered very reliable for evaluation of the virucidal activity of disinfectants. Broad-spectrum activity and high efficacy of three different tungsten carbide nanoparticles preparations is concluded.


Assuntos
Adenovírus Humanos/efeitos dos fármacos , Desinfetantes/farmacologia , Norovirus/efeitos dos fármacos , Poliovirus/efeitos dos fármacos , Compostos de Tungstênio/farmacologia , Vírus Vaccinia/efeitos dos fármacos , Animais , Desinfecção/métodos , Humanos , Nanopartículas Metálicas , Camundongos , Testes de Sensibilidade Microbiana
15.
Mar Pollut Bull ; 149: 110492, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31437615

RESUMO

Marine antifouling paints (MAPs) are widely used to prevent organisms from fouling vessel hulls. When scraped from vessels as part of regular maintenance, MAP particles discharged into the seawater become a source of toxic substances, like copper (Cu), to the environment, and biocides leaching from them are known to cause toxic effects on non-target organisms. We investigated the toxicity of MAP particles collected from a Bermuda boatyard on local copepod communities using two experiments. Copepod survival, Chlorophyll a and total dissolved Cu concentrations were measured before and after MAP particles addition. In an acute toxicity test, the addition of 0.3 g/L of MAP particles resulted in 0% copepods survival within 88 h and increased dissolved Cu by 1.8 µM. A significant inverse relationship was observed between copepod survival and MAP particles quantity, highlighting the toxic effects of MAP particles from boat maintenance on copepod communities in the surrounding seawater.


Assuntos
Copépodes , Cobre , Desinfetantes , Animais , Bermudas , Clorofila A , Copépodes/efeitos dos fármacos , Cobre/farmacologia , Cobre/toxicidade , Desinfetantes/farmacologia , Desinfetantes/toxicidade , Pintura , Água do Mar , Navios , Testes de Toxicidade Aguda , Poluentes Químicos da Água/análise
16.
Ophthalmic Physiol Opt ; 39(5): 337-349, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31435968

RESUMO

PURPOSE: The presence of biofilm in the lens case has been shown to be a risk factor for contamination of lenses and consequently microbial keratitis. This study aimed to evaluate effectiveness of solutions for rigid contact lenses in prevention and disruption of biofilm in lens cases and methods for biofilm detection. METHOD: This study adopted a stepwise approach to evaluate effectiveness of four rigid lens disinfecting solutions against biofilm. These included two polyhexamethylene bigiuanide (PHMB) solutions and a chlorhexidine/PHMB-based solution, as well as a novel povidone-iodine formulation. The presence of biofilm following exposure to the solutions was assessed using both crystal violet (CV) staining and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) viability assay, taking into account the effect of lens case design. Three lens case designs, conventional flat, large bucket type, and cylindrical cases, were investigated for the ability to trap stain and allow biofilm formation. RESULTS: Considerable differences were noted between solutions in their ability to prevent and disrupt biofilm (p < 0.001). Lens case design greatly influenced optical density (OD) measurements even in negative controls, as cylindrical cases trapped more stain, increasing OD readings. Correcting for this factor reduced variations, but could not differentiate between residues and biofilm. MTT assay revealed that both povidone-iodine and chlorhexidine-containing solutions could effectively kill > 95% of organisms, whilst PHMB-based solutions were less effective with up to 55% of staphylococci and 41% of Pseudomonas surviving at 24 h. CONCLUSION: Biofilm can rapidly form in lens cases and may not be killed by disinfecting solutions. Of the solutions tested, none were able to prevent biofilm formation or disrupt established biofilm, but those containing chlorhexidine or povidone iodine were able to penetrate the biofilm and kill organisms. Assessment of biofilm by CV assay may be confounded by lens case design. Whilst CV assay can demonstrate presence of biofilm, this technique should be accompanied by viability assay to determine bactericidal activity.


Assuntos
Biofilmes/efeitos dos fármacos , Soluções para Lentes de Contato/farmacologia , Lentes de Contato Hidrofílicas/microbiologia , Desinfetantes/farmacologia , Biguanidas/farmacologia , Clorexidina/farmacologia , Humanos , Povidona-Iodo/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
17.
J Appl Microbiol ; 127(5): 1315-1326, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31379024

RESUMO

AIMS: (i) To develop an analytical method for recovery and quantification of bacteriophage MS2-as a surrogate for foot-and-mouth disease virus-from complex porous surfaces, with and without the presence of laboratory-developed agricultural grime; (ii) to evaluate, with a 4-log dynamic range, the virucidal activity of common biocides for their ability to decontaminate surfaces and hence remediate facilities, following a foreign animal disease contamination incident. METHODS AND RESULTS: An analytical method was developed and optimized for MS2 recovery from simulated agricultural surfaces. The addition of Dey-Engley neutralizing broth to an extraction buffer improved MS2 viability in liquid extracts, with optimal analytical holding times determined as <8 to ≤24 h, depending on matrix. The recovery of MS2 from surface materials decreased in the order: nonporous reference material >grimed porous materials >nongrimed porous materials. In disinfectant testing, two spray applications of pAB were effective against MS2 (≥4-log reduction) on all operational-scale materials. Two per cent citric acid had limited effectiveness, with a ≥4-log reduction observed on a selected subset of grimed concrete samples. CONCLUSIONS: Decontamination efficacy test results can be affected by surface characteristics, extraction buffer composition, analytical holding time and surface-specific organism survivability. Efficacy should be evaluated using a test method that reflects the environmental characteristics of the intended application. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study demonstrate the importance of analytical method verification tests for disinfectant testing prior to application in complex environments.


Assuntos
Descontaminação/métodos , Desinfetantes/farmacologia , Levivirus/efeitos dos fármacos , Agricultura , Desinfetantes/administração & dosagem , Levivirus/fisiologia , Viabilidade Microbiana/efeitos dos fármacos , Porosidade , Solo
18.
J Fish Dis ; 42(10): 1383-1389, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31322740

RESUMO

Tilapia lake virus (TiLV) is an emerging virus associated with high fish mortality and economic losses. This study investigates the virucidal effects of the following disinfectants (active ingredients) on TiLV: 2.5 ppm iodine, 10 ppm sodium hypochlorite (NaOCl), 300 ppm hydrogen peroxide (H2 O2 ), 80 ppm formalin and 5,000 ppm (0.5%) Virkon® . Factors that affect the disinfectants' efficacy, including temperature, contact time and soiling (organic matter) interference, were examined under conditions mimicking natural aquaculture practices. TiLV inactivation of higher than 5 log10 TCID50  ml-1 was achieved after 10 min and at 28°C for all disinfectants except formalin; similar inactivation levels were reached by NaOCl and Virkon® at 10 min and 4°C. Extended exposure to formalin from 10 to 60 min at 28°C rendered more than 5 log10 inactivation. Increasing synthetic organic matter in the water to mimic soiling interference reduced the efficacy of NaOCl, iodine and H2 O2 when tested at 10 min and 28°C; however, Virkon® still achieved more than 5 log10 inactivation. This study demonstrates that most common disinfectants effectively reduced viral loads to minimum levels. To limit the spread of TiLV in aquaculture farms and related facilities, the appropriate use of such disinfectants should therefore be promoted and implemented.


Assuntos
Desinfetantes/farmacologia , Doenças dos Peixes/tratamento farmacológico , Tilápia , Viroses/veterinária , Inativação de Vírus , Animais , Doenças dos Peixes/virologia , Especificidade da Espécie , Viroses/tratamento farmacológico , Viroses/virologia , Vírus/efeitos dos fármacos
19.
Meat Sci ; 157: 107886, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31323451

RESUMO

Several studies have been conducted to verify the decontamination potential of electrolytically-generated hypochlorous acid, peroxyacetic acid, lactic acid and caprylic acid against Shiga toxin-producing Escherichia coli (STEC) in beef products. However, there is no consensus regarding their effectiveness. The aim of this study was to compare these four treatments under the same conditions and establish a ranking according to their effectiveness to inactivate STEC in fresh beef. Samples were inoculated with two levels of inoculum and rinsed for 15 s in 100 mL of antimicrobial solution treatment. Caprylic acid was the most effective treatment, followed by lactic acid and peroxyacetic acid. Electrolytically-generated hypochlorous acid had no effect. Sensory analysis showed no significant differences either in flavor or in color between samples treated with caprylic acid and reference samples. Caprylic acid appears to be an effective and viable alternative to conventional interventions frequently used for meat product decontamination.


Assuntos
Desinfetantes/farmacologia , Carne Vermelha/microbiologia , Escherichia coli Shiga Toxigênica/efeitos dos fármacos , Animais , Caprilatos/farmacologia , Bovinos , Contaminação de Alimentos/prevenção & controle , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Ácido Hipocloroso/farmacologia , Ácido Láctico/farmacologia , Ácido Peracético/farmacologia
20.
Hum Exp Toxicol ; 38(11): 1314-1326, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31303057

RESUMO

Electrolyzed water (EW) is a widely used disinfectant agent with high oxidation-reduction potential (ORP). Although EW has been used in many areas, such as food hygiene, agriculture, and animal husbandry, the studies presented in the literature are not enough to clarify the toxic effects of EW. The aim of this study is, therefore, to produce EWs at different pH, ORP, and chlorine concentrations and to assess their safety in terms of toxicology. At the beginning of the study, the antimicrobial activity of the EW types with respect to bacteria and fungus was investigated. EWs below pH 7 were all effective in inactivating Enterococcus hirae, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans completely. In vitro studies of cell cultures revealed that different concentrations of EWs were not cytotoxic for the L929 cells under 10- to 80-fold dilutions. In addition, it has been determined that produced EWs did not have irritation potential, according to the in vitro EpiDerm™, reconstituted skin irritation test in the frames of biocompatibility tests. For the mucous membrane irritation test, the hen's egg test-chorioallantoic membrane experiment was performed, and EWs were found to have no eye irritation. In conclusion, it has been shown that produced EWs with antimicrobial efficacy were found to be safe for skin and eye according to in vitro biocompatibility study studies. Thus, the establishment of a technological infrastructure for the EW production and the use of produced EW as an effective disinfectant in the food, medical, and agricultural areas should be encouraged.


Assuntos
Desinfetantes/farmacologia , Eletrólise , Água/farmacologia , Animais , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Embrião de Galinha , Membrana Corioalantoide/efeitos dos fármacos , Desinfetantes/química , Olho/efeitos dos fármacos , Humanos , Interleucina-1alfa/metabolismo , Camundongos , Pele/efeitos dos fármacos , Pele/metabolismo , Testes de Irritação da Pele , Água/química
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