Avaliação da técnica de detecção por fluorescência como alternativa para contagem de bactérias heterotróficas em água para hemodiálise

Introduction: The microbiological quality of hemodialysis treated water is directly related to the occurrence of infections and pyrogenic reactions in patients. Objective: Determine the minimum incubation time and evaluate the alternative microbiological method performance for heterotrophic bacteria count in hemodialysis water through the fluorescence microbial detection technique. Method: The analyses were conducted by concentration levels of 2,5 x 10-1 to 1,0 x 102 CFU/plate for Pseudomonas aeruginosa, Burkholderia cepacia, Escherichia coli and Staphylococcus aureus. The tests were performed simultaneously by the alternative and the traditional methods, using culture medium R2A and incubation temperature of 24.0°C ± 4.0°C. The incubation times were 40 h and 120 h, respectively. Fourteen hemodialysis water samples were analyzed to assess the equivalence between the methods evaluated. Results: The results demonstrated that the alternative method allows quantification of heterotrophic bacteria after 40 h of incubation, with accuracy, precision, specificity and linearity for the range of 5 to 100 CFU/plate. The detection limit of the alternative method is 1 CFU/plate. Conclusions: It was possible to conclude that the alternative method has equivalent results to the traditional method, since the confidence interval of the alternative method was entirely within the equivalence range. Therefore, the microbial detection technique by fluorescence showed a viable option for the implementation of a rapid microbiological method for the heterotrophic bacteria count in samples of treated water for hemodialysis.Introdução: A qualidade microbiológica da água tratada para hemodiálise está diretamente relacionada à ocorrência de infecções e de reações pirogênicas nos pacientes. Objetivo: Determinar o tempo de incubação mínimo e avaliar o desempenho do método microbiológico alternativo para a contagem de bactérias heterotróficas em água de hemodiálise por meio da técnica de detecção microbiana por fluorescência. Método: As análises foram conduzidas com níveis de concentração entre 2,5 x 10-1 e 1,0 x 102 UFC/placa para Pseudomonas aeruginosa, Burkholderia cepacia, Escherichia coli e Staphylococcus aureus. Os testes foram realizados simultaneamente pelos métodos alternativo e tradicional, utilizando o meio de cultura R2A e temperatura de incubação de 24,0°C ± 4,0°C. Os tempos de incubação empregados foram os de 40 h e 120 h, respectivamente. Quatorze amostras de água para hemodiálise foram analisadas para avaliação da equivalência entre os métodos avaliados. Resultados: Os resultados demonstraram que o método alternativo permite a quantificação de bactérias heterotróficas após 40 h de incubação, com precisão, exatidão, especificidade e linearidade para a faixa de 5 a 100 UFC/placa. O limite de detecção do método alternativo é 1 UFC/placa. Conclusões: O método alternativo possui resultados equivalentes ao método tradicional, uma vez que o intervalo de confiança do método alternativo obtido esteve compreendido inteiramente dentro da faixa de equivalência. Portanto, a técnica de detecção microbiana por fluorescência mostrou ser uma opção viável para a implementação de um método microbiológico rápido para a contagem de bactérias heterotróficas em amostras de água tratada para hemodiálise

Lmx1b is required for the glutamatergic fates of a subset of spinal cord neurons

Background: Alterations in neurotransmitter phenotypes of specific neurons can cause imbalances in excitation and inhibition in the central nervous system (CNS), leading to diseases. Therefore, the correct specification and maintenance of neurotransmitter phenotypes is vital. As with other neuronal properties, neurotransmitter phenotypes are often specified and maintained by particular transcription factors. However, the specific molecular mechanisms and transcription factors that regulate neurotransmitter phenotypes remain largely unknown. Methods: In this paper we use single mutant, double mutant and transgenic zebrafish embryos to elucidate the functions of Lmx1ba and Lmx1bb in the regulation of spinal cord interneuron neurotransmitter phenotypes. Results: We demonstrate that lmx1ba and lmx1bb are both expressed in zebrafish spinal cord and that lmx1bb is expressed by both V0v cells and dI5 cells. Our functional analyses demonstrate that these transcription factors are not required for neurotransmitter fate specification at early stages of development, but that in embryos with at least two lmx1ba and/or lmx1bb mutant alleles there is a reduced number of excitatory (glutamatergic) spinal interneurons at later stages of development. In contrast, there is no change in the numbers of V0v or dI5 cells. These data suggest that lmx1b-expressing spinal neurons still form normally, but at least a subset of them lose, or do not form, their normal excitatory fates. As the reduction in glutamatergic cells is only seen at later stages of development, Lmx1b is probably required either for the maintenance of glutamatergic fates or to specify glutamatergic phenotypes of a subset of later forming neurons. Using double labeling experiments, we also show that at least some of the cells that lose their normal glutamatergic phenotype are V0v cells. Finally, we also establish that Evx1 and Evx2, two transcription factors that are required for V0v cells to acquire their excitatory neurotransmitter phenotype, are also required for lmx1ba and lmx1bb expression in these cells, suggesting that Lmx1ba and Lmx1bb act downstream of Evx1 and Evx2 in V0v cells. Conclusions: Lmx1ba and Lmx1bb function at least partially redundantly in the spinal cord and three functional lmx1b alleles are required in zebrafish for correct numbers of excitatory spinal interneurons at later developmental stages. Taken together, our data significantly enhance our understanding of how spinal cord neurotransmitter fates are regulated

Is dialysis water a safe component for hemodialysis treatment in São Paulo State, Brazil?

Failure on the water treatment poses hemodialysis patients at risk of injury and death. Identifying if the patients are exposed to water quality related microbiological risks is an important objective to reduce the mortality for chronic renal patients and is the main issue of this study. We evaluated the microbiological water quality used by 205 dialysis services in São Paulo State, Brazil between 2010 to 2016. The study included heterotrophic bacteria count, total coliforms research, and bacterial endotoxin determination in 1366 dialysis water samples. The number of unsatisfactory clinics for at least one microbiological parameter decreased 16.0% between 2010 to 2015 but increased 57.2% in 2016. In 2010, the most frequent unsatisfactory parameter was related to heterotrophic bacteria count (54.8%) followed by endotoxin determination (45.2%). However, in 2013 an opposite situation was observed: endotoxin determination as the parameter of the higher incidence of nonconformities. Total coliform was verified at a lower frequency. We highlighted the importance of regular monitoring of dialysis water quality to prevent infections caused by dialytic procedures and to ensure that the water is a safe component of the treatment