Physical and chemical quality, biodiversity, and thermodynamic prediction of adhesion of bacterial isolates from a water purification system: a case study

The objective of this study was to evaluate the quality of water purification system and identify the bacteria this system, predict bacterial adherence according to the hydrophobicity of these microorganisms and of the polypropylene distribution loop for purified water. The assessment of drinking water that supplies the purification system allowed good-quality physical, chemical, and microbiological specifications. The physicochemical specifications of the distributed purified water were approved, but the heterotrophic bacteria count was higher than allowed (>;2 log CFU mL-1).The sanitation of the storage tank with chlorine decreased the number of bacteria adhered to the surface (4.34 cycles log). By sequencing of the 16SrDNA genes, six species of bacteria were identified. The contact angle was determined and polypropylene surface and all bacteria were considered to be hydrophilic, and adhesion was thermodynamically unfavorable. This case study showed the importance of monitoring the water quality in the purified water systems and the importance of sanitization with chemical agents. The count of heterotrophic bacteria on the polypropylene surface was consistent with the predicted thermodynamics results because the number of adhered cells reached approximate values of 5 log CFU cm-2

ATLANTIC EPIPHYTES: a data set of vascular and non-vascular epiphyte plants and lichens from the Atlantic Forest

Epiphytes are hyper-diverse and one of the frequently undervalued life forms in plant surveys and biodiversity inventories. Epiphytes of the Atlantic Forest, one of the most endangered ecosystems in the world, have high endemism and radiated recently in the Pliocene. We aimed to (1) compile an extensive Atlantic Forest data set on vascular, non-vascular plants (including hemiepiphytes), and lichen epiphyte species occurrence and abundance; (2) describe the epiphyte distribution in the Atlantic Forest, in order to indicate future sampling efforts. Our work presents the first epiphyte data set with information on abundance and occurrence of epiphyte phorophyte species. All data compiled here come from three main sources provided by the authors: published sources (comprising peer-reviewed articles, books, and theses), unpublished data, and herbarium data. We compiled a data set composed of 2,095 species, from 89,270 holo/hemiepiphyte records, in the Atlantic Forest of Brazil, Argentina, Paraguay, and Uruguay, recorded from 1824 to early 2018. Most of the records were from qualitative data (occurrence only, 88%), well distributed throughout the Atlantic Forest. For quantitative records, the most common sampling method was individual trees (71%), followed by plot sampling (19%), and transect sampling (10%). Angiosperms (81%) were the most frequently registered group, and Bromeliaceae and Orchidaceae were the families with the greatest number of records (27,272 and 21,945, respectively). Ferns and Lycophytes presented fewer records than Angiosperms, and Polypodiaceae were the most recorded family, and more concentrated in the Southern and Southeastern regions. Data on non-vascular plants and lichens were scarce, with a few disjunct records concentrated in the Northeastern region of the Atlantic Forest. For all non-vascular plant records, Lejeuneaceae, a family of liverworts, was the most recorded family. We hope that our effort to organize scattered epiphyte data help advance the knowledge of epiphyte ecology, as well as our understanding of macroecological and biogeographical patterns in the Atlantic Forest. No copyright restrictions are associated with the data set. Please cite this Ecology Data Paper if the data are used in publication and teaching events. © 2019 The Authors. Ecology © 2019 The Ecological Society of Americ

Modeling of adhesion and biofilm formation in monoculture of Escherichia coli, Listeria monocytogenes e Salmonella enterica subsp. Enterica and evaluation of the interaction in co-culture with Enterococcus faecalis

A adesão e formação de biofilmes por bactérias patogênicas e deteriorantes são indesejáveis na indústria de alimentos devido aos problemas de contaminação e a difícil remoção no processo de higienização. Desta forma, é importante quantificar e minimizar o risco de adesão e fatores que o afeta, uma ferramenta para 1sso é utilizar a microbiologia preditiva, que permite prever as influências das condições ambientais no comportamento microbiano. Além disso, os biofilmes são formados por várias espécies bacterianas, e possíveis Interações entre as espécies podem ocorrer, por exemplo, as interações sinérgicas podem tornar os membros desta comunidade mais tolerantes e resistentes aos sanitizantes, já nas interações competitivas ou antagônicas pode ocorrer a presença de micro-organismos inibidores de outros individuos nos biofilmes. Nesse contexto, a primeira parte do trabalho aborda o desenvolvimento de modelos matemáticos preditivos de adesão e formação de biofilmes das bactérias Escherichia coli, Listeria monocytogenes, e Salmonella enterica subsp. enterica e E. faecalis, em função dos efeitos do pH e temperatura. Utilizou-se microplacas de poliestireno com 96 poços contendo caldo Brain Heart Infusion em pH ajustado para a adesão e formação de biofilmes, os ensaios foram conduzidos em diferentes combinações de pH (4, 5,6, 7,8,€e 9) e temperatura (5 °C, 15°C, 25 °C, 25 °C e 45 °C). Com os dados experimentais, modelos de probabilidade de regressao logistica foram construidos para cada bacteria, os modelos apresentaram bom ajuste com poder preditivo adequado e, verificou-se que com o aumento da temperatura o risco de o evento acontecer é maior. Na segunda parte do estudo os objetivos foram verificar as interações sinérgicas em cocultura entre as bactérias e avaliar a capacidade antagônica de E. faecalis em competir, excluir ou deslocar os patógenos durante a formação dos biofilmes em diferentes temperaturas e correlacionar essa inibição com as propriedades de autoagregação e coagregação. Finalmente, determinar a cinética de inativação dos micro-organismos patogênicos presentes nos biofilmes em monocultura e em cocultura com E. faecalis sob ação do sanitizantes dicloroisocianurato de sódio e cloreto de benzalcônio e avaliar se houve aumento da resistência para inativação dos biofilmes quando cultivados em cocultura. Poucas ocorrências de efeitos sinérgicos foram encontradas na formação de biofilmes entre os isolados, em 144 combinações houve somente quatro efeitos sinérgicos que foram: S. enterica e L. monocytogenes nas temperaturas de 15 CempH8€e9,a25 CempH8e também E. coli e E. faecalis na temperatura de 35 CepH8. E. faecalis teve pouca capacidade em inibir a formação de biofilmes dos patógenos, promovendo baixas reduções decimais (<1 ciclos log) pelos três mecanismos investigados: competição, exclusão ou deslocamento. A capacidade de coagregação de E. faecalis com os patógenos também foi baixa e, esta baixa porcentagem de coagregação (< 20%) pode indicar porque houve pouca capacidade de inibir ou diminuir a adesão desses patógenos pelos mecanismos de inibição de biofilmes testados. As cinéticas de inativacao dos biofilmes dos patógenos em monocultura ou cocultura com E. faecalis sob ação dos sanitizantes teve um bom ajuste ao modelo bifásico de Cerf, e permitiu informações detalhadas sobre as taxas de inativação correspondentes às subpopulações sensíveis e resistentes e com base nas análises dos parâmetros cinéticos f, kmax, kmax? € valores D, além do tempo de redução de 4 ciclos log ficou claro que não houve aumento da resistência do composto clorado na inativação de todos os patógenos nos biofilmes em cocultura. Nos biofilmes de Salmonella e E. coli em cocultura com E. faecalis também não apresentaram resistência ao cloreto de benzalcônio, entretanto, Listeria em biofilmes de cocultura com E. faecalis, demostrou pelos paramentros cinéticos que ocorreu um aumento da resistência ao cloreto de benzalcônio. As imagens de microscopia eletrônica de varredura obtidas para o biofilme em monocultura e cocultura mostraram que não houve diferença visual na arquitetura dos biofilmes para as espécies estudadas.Adhesion and formation of biofilms by pathogenic and spoilage bacteria are undesirable in the food industry due to food contamination problems and difficult removal in the sanitation process. Thus, it 1s important to quantify and minimize the risk of adhesion and factors that affect it, a tool for this is to use predictive microbiology, which allows predicting the influence of environmental conditions on microbial behavior. In addition, biofilms are formed by several bacterial species, and possible interactions between Species can occur, for example, synergistic interactions can make members of this community more tolerant and resistant to sanitizers, whereas in competitive or antagonistic interactions the presence may occur of inhibiting microorganisms from other individuals in biofilms. In this context, the first part of the work addresses the development of predictive mathematical models of adhesion and biofilm formation of the bacteria Escherichia coli, Listeria monocytogenes, and Salmonella enterica subsp. enterica and E. faecalis, as a function of the effects of pH and temperature. Polystyrene microplates with 96 wells containing Brain Heart Infusion broth at pH adjusted for adhesion and biofilm formation were used, the assays were conducted in different combinations of pH (4, 5, 6, 7, 8, and 9) and temperature (5 °C, 15 °C, 25 °C, 25 °C and 45 °C). With the experimental data, logistic regression probability models were built for each bacterium, the models showed a good fit with adequate predictive power, and it was found that with increasing temperature the risk of the event happening 1s greater. In the second part of the study, the objectives were to verify the synergistic interactions in coculture between bacteria and to evaluate the antagonistic capacity of EF. faecalis to compete, exclude or displace pathogens during the formation of biofilms at different temperatures and to correlate this inhibition with the properties of self-aggregation and co-agegregation. Finally, to determine the inactivation kinetics of pathogenic microorganisms present in biofilms in monoculture and in coculture with £. faecalis under the action of sanitizers sodium dichloroisocyanurate and benzalkonium chloride and to evaluate if there was an increase in resistance to inactivation of biofilms when cultivated in co-culture. Few occurrences of synergistic effects were found in the formation of biofilms among the isolates, in 144 combinations there were only 4 synergistic effects which were: S. enterica and L. monocytogenes at temperatures from 15 °C at pH 8 and 9, to 25 °C at pH 8 and also E. coli and E. faecalis at a temperature of 35 °C and pH 8. E. faecalis had little capacity to inhibit the formation of pathogen biofilms, promoting low decimal reductions (<1 log cycles) by the three mechanisms investigated: competition, exclusion or displacement. The coaggregation capacity of E. faecalis with pathogens was also low, and this low percentage of coaggregation (< 20%) may indicate why there was little capacity to inhibit or decrease the adhesion of these pathogens by the biofilm inhibition mechanisms tested. The biofilm inactivation kinetics of pathogens in monoculture or coculture with £. faecalis under the action of sanitizers had a good fit to the Cerf biphasic model, and allowed detailed information on the inactivation rates corresponding to sensitive and resistant subpopulations and based on the analysis from the kinetic parameters f) kmax1, Kmax2,, and D values, in addition to the reduction time of 4 log cycles, 1t was clear that there was no increase in the resistance of the chlorinated compound to the inactivation of all pathogens in biofilms in coculture. In biofilms of Salmonella and E. coli co-cultured with £. faecalis also did not show resistance to benzalkonium chloride, however, Listeria in biofilms co-cultured with E. faecalis, demonstrated by the kinetic parameters that there was an increase in resistance to benzalkonium chloride. Scanning electron microscopy images obtained for biofilm in monoculture and coculture showed that there was no visual difference 1n the architecture of the biofilms for the studied species.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Microbial diversity and quality of water obtained by purification system installed in the building of Quality and Food Safety Laboratories

A água purificada exerce um papel fundamental na rotina laboratorial e em diversas aplicações, exigindo elevado grau de pureza. Deste modo, foi realizada uma avaliação da qualidade da água distribuída pelo sistema de purificação de água instalado nos Laboratórios de Qualidade e Segurança de Alimentos do Departamento de Tecnologia de Alimentos da UFV. A primeira parte do trabalho aborda a qualidade físico-química e microbiológica da água potável que alimenta o sistema de purificação e também a qualidade da água obtida e distribuída nos pontos de uso. A instalação e as condições de operação e desempenho do sistema de purificação de água foram avaliados. A avaliação da água potável que abastece o sistema de purificação permitiu constatar uma boa qualidade, tanto para as especificações físico-químicas (alcalinidade 20,3 mg·L-1 CaCO3, condutividade 62,7 &#956;S·cm-1, cloro residual livre 0,84 mg·L-1, pH 6,17, temperatura 25 °C, índice de saturação de Langelier -3,76, dureza 20 mg·L-1 CaCO3, e sílica 15,2 mg·L- SiO2) quanto microbiológicas (1,24 log10 UFC·mL-1). A água purificada obtida pelo sistema esteve sempre de acordo com as especificações físico-químicas e microbiológicas estabelecidas pelo fabricante do equipamento e pela Farmacopeia Brasileira. A água purificada distribuída foi aprovada nas especificações físico-químicas, porém o nível de contagem de bactérias heterotróficas estava acima do permitido (>2 log10 UFC·mL-1), o que pode comprometer alguns resultados analíticos dos laboratórios. Foi verificado ainda que higienização do reservatório de água potável e do reservatório de água purificada deve ser feita a cada 6 meses, uma vez que os resultados deste procedimento mostraram redução significativa (p0) entre a superfície e todas as espécies identificadas. Os resultados de predição termodinâmica foram compatíveis com as contagens de bactérias heterotróficas da superfície de polipropileno (loop de distribuição) que atingiram valores de aproximadamente 5 log10 UFC·cm-2, indicando que não se caracteriza como biofilmes.Purified water exert a fundamental role in routine clinical practice and in many applications requiring high purity. Thus, an assessment of the quality of the water distributed by water purification system installed in the Laboratory of Quality and Food Safety of the Department of Food Technology at UFV was performed. The first part of the paper deals with physical-chemical and microbiological quality of drinking water that feeds the purification system and the quality of water produced and distributed at points of use. The installation and operating conditions and performance of the water purification system were evaluated. The evaluation of drinking water supply purification system have revealed a good quality for both the physical and chemical specifications (alkalinity 20,3 mg·L-1 CaCO3, conductivity 62,7 &#956;S·cm-1, chlorine 0,84 mg·L-1, pH 6,17, temperature 25 °C, Langelier Saturation Index -3,76, hardness 20 mg·L-1 CaCO3 and silica 15,2 mg·L-1 SiO2) and microbiological (1,24 log10 UFC·mL-1). The purified water produced by the system always in accordance with the specifications established by the equipment manufacturer. Purified water distributed showed the physicochemical requirements within the allowed, but the levels of heterotrophic bacteria counts were higher than allowed (> 2 log10 UFC·mL-1), which may compromise some analytical results performed in laboratories. It was found, although cleaning of drinking water reservoir and the reservoir of purified water should be performed every 6 months, once the results of this procedure showed a significant reduction (p 0) between the surface and all identified species. The species studied were considered and the surface hydrophilic. Adherence was not thermodynamically favorable (&#916;G membership > 0) between the surface and all identified species. The results of thermodynamic prediction were consistent with heterotrophic bacteria counts the surface of polypropylene (loop distribution) which reached values of approximately 5 log10 CFU· cm-2 indicating that it is characterized as biofilms.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Physical and chemical quality, biodiversity, and thermodynamic prediction of adhesion of bacterial isolates from a water purification system: a case study

ABSTRACT The objective of this study was to evaluate the quality of water purification system and identify the bacteria this system, predict bacterial adherence according to the hydrophobicity of these microorganisms and of the polypropylene distribution loop for purified water. The assessment of drinking water that supplies the purification system allowed good-quality physical, chemical, and microbiological specifications. The physicochemical specifications of the distributed purified water were approved, but the heterotrophic bacteria count was higher than allowed (>2 log CFU mL-1).The sanitation of the storage tank with chlorine decreased the number of bacteria adhered to the surface (4.34 cycles log). By sequencing of the 16SrDNA genes, six species of bacteria were identified. The contact angle was determined and polypropylene surface and all bacteria were considered to be hydrophilic, and adhesion was thermodynamically unfavorable. This case study showed the importance of monitoring the water quality in the purified water systems and the importance of sanitization with chemical agents. The count of heterotrophic bacteria on the polypropylene surface was consistent with the predicted thermodynamics results because the number of adhered cells reached approximate values of 5 log CFU cm-2

Núcleos de Ensino da Unesp: artigos 2008

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq