RESUMO

Campylobacteriosis is one of the most common bacteria causing human gastroenteritis. Poultry is a major reservoir of Campylobacter spp. as well as the main source of transmission. Due to the increased occurrence of campylobacteriosis, poultry slaughterhouses are under pressure to deliver carcasses with low contamination. However, a few studies have been carried out to evaluate Campylobacter contamination of broiler carcasses in Brazilian slaughter lines. Therefore, in this study, we aimed at detecting and quantifying the thermotolerant Campylobacter spp. at different stages of the poultry slaughtering process. The samples were collected from 12 points in three slaughterhouses in southern Brazil, at an interval of 12 months, and were tested for Campylobacter spp. by conventional microbiological technique, the most probable number, and real-time PCR. A total of 432 samples were analyzed. The majority of strains belonged to Campylobacter jejuni (92%), and the flock positivity among the three techniques was similar in most cases. Campylobacter was detected in all slaughtering stages. Although contamination has remained similar (p > 0.05) throughout almost all the slaughter process, evisceration seemed to be an important source of contamination. Our results reinforce the idea that the final carcass quality after the slaughtering process is directly influenced by the level of contamination of the broiler flocks on arrival at the processing plant.

Assuntos

RESUMO

Abstract This study evaluated an intermittently aerated, fixed-bed, single-batch reactor, with mini BioBob© as biofilm media support, as an alternative treatment of craft brewery wastewater. In order to remove chemical oxygen demand (COD) and total nitrogen (TN), seven conditions were performed in a central composite experimental design (CCD) with different aeration times (1, 2 and 3 h in a 4 h cycle) and hydraulic retention times (HRT) (12, 16 and 20 h). The results showed that the removal of COD and TN were positively affected by increased aeration time and HRT. The condition that presented the best quality effluent was Condition No. 1 (20 h HRT and 3 h aeration), with 209 ± 28 mg COD L-1; 3.00 ± 0.15 mg TKN L-1 ; and 0.67 ± 0.11 mg NO3-N L-1. Kinetic assays showed that the highest values for the substrate removal rate constant, kCOD = 0.1774 h-1 were obtained with the longest aeration time (3 h). The most probable number (MPN) test showed a higher concentration of denitrifying bacteria (heterotrophic), 3.3 x 106, than for AOB and NOB bacteria (autotrophic), which were 4.9 x 103 and 2.7 x 103, respectively. Moreover, it was possible to verify that correcting the influent alkalinity with 7.14 mg CaCO3 for each 1 mg of TKN resulted in better process efficiency. It was concluded that COD and TN can be removed from craft brewery wastewater using an intermittently aerated, fixed-bed, single-batch reactor with mini Biobob© as biofilm media support.

Assuntos

RESUMO

Products such as milk and cheese produced by hand and sold by small producers in open markets and at home are a reality in Brazil, despite legal prohibitions. In many cases, this leads to the production of food without hygienic conditions, which may constitute an important source of transmission of foodborne diseases and a danger to public health. This study proposes to examine the hygienic-sanitary quality of milk and cheese sold illegally in municipalities of northern Mato Grosso, Brazil, to undertake a phenotypical investigation of the presence of resistance of isolated colonies to antimicrobials and to detect the production of ß-lactamase enzymes: extended-spectrum ß-lactamase (ESBL), AmpC ß-lactamases (AmpC) and carbapenemases. The 25 milk and 37 cheese samples analyzed were subjected to the most probable number (MPN) test, isolation on eosin-methylene blue agar (EMB) agar and Escherichia coli identification by biochemical tests and disk diffusion test. Results showed that 76% of the milk samples and 67.57% of the cheese samples had thermotolerant coliform counts above the value allowed by the legislation. The milk and cheese isolates showed 15.79 and 5.88% resistance, respectively, to at least one of the tested antimicrobials. No ß-lactamase enzyme production was observed in the isolates.

Assuntos

RESUMO

ABSTRACT Products such as milk and cheese produced by hand and sold by small producers in open markets and at home are a reality in Brazil, despite legal prohibitions. In many cases, this leads to the production of food without hygienic conditions, which may constitute an important source of transmission of foodborne diseases and a danger to public health. This study proposes to examine the hygienic-sanitary quality of milk and cheese sold illegally in municipalities of northern Mato Grosso, Brazil, to undertake a phenotypical investigation of the presence of resistance of isolated colonies to antimicrobials and to detect the production of -lactamase enzymes: extended-spectrum -lactamase (ESBL), AmpC -lactamases (AmpC) and carbapenemases. The 25 milk and 37 cheese samples analyzed were subjected to the most probable number (MPN) test, isolation on eosin-methylene blue agar (EMB) agar and Escherichia coli identification by biochemical tests and disk diffusion test. Results showed that 76% of the milk samples and 67.57% of the cheese samples had thermotolerant coliform counts above the value allowed by the legislation. The milk and cheese isolates showed 15.79 and 5.88% resistance, respectively, to at least one of the tested antimicrobials. No -lactamase enzyme production was observed in the isolates.

RESUMO

Resumen Objetivo: Validar en Colombia la escala abreviada de síntomas representativos de neoplasias mieloproliferativas para su posterior uso en investigación y aplicación en el ámbito clínico. Materiales y métodos: Se realizó la adaptación transcultural de la escala MPN-SAF-TSS (por sus siglas en inglés: Mieloproliferative Neoplasm Symptom Assesment Form-Total Sympton Score) a español y al contexto colombiano, con análisis estadísticos de validez y confiabilidad con un tamaño de muestra determinado para cada propiedad psicométrica. Resultados: Con base en las propiedades psicométricas se logró verificar la confiabilidad y la estructura interna de la escala con alfa de Cronbach de 0,8552, lo que denota una buena consistencia interna; se obtuvo un coeficiente de correlación de concordancia de Lin de 0,765 que muestra una buena confiabilidad. El análisis factorial mostró múltiples valores de coeficiente de correlación por encima de 0,3, lo que indica que las variables de la escala miden factores comunes; la validez de criterio concurrente determina que la escala mide lo que debe medir con un adecuado coeficiente de correlación de Spearman de -0,71 y -0,73 al confrontarla con las escalas FACIT-Fatigue y Fact-Lym respectivamente. Conclusión: La escala MPN-SAF-TSS adaptada a español y al contexto colombiano es un instrumento válido para la evaluación de síntomas en pacientes con neoplasias mieloproliferativas y puede ser utilizado en la práctica clínica o en estudios clínicos por sus adecuadas propiedades psicométricas.

Abstract Objective: To validate in Colombia the abbreviated scale of representative symptoms of myeloproliferative neoplasms, for further use in research and for application in the clinical setting. Materials and methods: A cross-cultural adaptation of the MPN-SAF TSS-scale (mieloproliferative neoplasm symptom assessment form total symptom score) to Colombian Spanish using statistical validity and reliability analysis with a specific sample size for each psychometric property. Results. Based on the psychometric properties, the verification of reliability and internal structure with a Cronbach's alpha scale of 0.8552 was achieved, denoting good internal consistency. A Lin's concordance correlation coefficient of 0.765 was obtained, showing good reliability; factor analysis showed multiple correlation coefficient values above 0.3, indicating that the scale variables measure common factors. Concurrent validity determines that the scale measures what it should measure with an adequate Spearman correlation coefficient of -0.71 and -0.73 when confronted with the FACIT-Fatigue and Fact-Lym scales, respectively. Conclusion: The MPN-SAF-TSS scale adapted to Colombian Spanish is a valid assessment instrument for symptoms in patients with myeloproliferative neoplasms and can be used in clinical practice or trials due to its adequate psychometric properties.

Resumo Objetivo: Validar na Colômbia, a escala abreviada de sintomas representativos de neoplasias mielo-proliferativas, para u seu posterior uso em investigação e a sua aplicação no âmbito clínico. Materiais e métodos: Realizou-se a adaptação transcultural da escala MPN-SAF-TSS (pelas suas siglas em inglês mieloproliferative neoplasm symptom assesment form total sympton score) ao espanhol colombiano, com análises estadísticas de validez e confiabilidade com um tamanho de amostra determinado para cada propriedade psicométrica. Resultados: Com base nas propriedades psicomé-tricas conseguiu-se verificar a confiabilidade e a estrutura interna da escala com alfa de Cronbach de 0,8552, o que denota uma boa consistência interna; se obteve um coeficiente de correlação de concordância de Lin de 0,765 mostrando uma boa confiabilidade; a análise fatorial mostrou múltiplos valores de coeficiente de correlação por acima de 0.3 indicando que as variáveis da escala medem fatores comuns, a validez de critério concorrente determina que a escala mede o que deve medir, com um adequado coeficiente de correlação de Spearman de -0,71 e -0,73 ao confrontá-la com as escalas FACIT-Fatigue e Fact-Lym respectivamente. Conclusão: A escala MPN-SAF TSS adaptada ao espanhol colombiano, é um instrumento válido para a avaliação de sintomas em pacientes com neoplasias mieloproliferativas e pode ser utilizado na prática clínica ou em estudos clínicos pelas suas adequadas propriedades psicométricas.

Assuntos

RESUMO

Bacterial pathogens are a leading cause of waterborne disease, and may result in gastrointestinal outbreaks worldwide. Inhabitants of the Bassaseachic Falls National Park in Chihuahua, Mexico show seasonal gastroenteritis problems. This aim of this study was to detect enteropathogenic microorganisms responsible for diarrheal outbreaks in this area. In 2013, 49 surface water samples from 13 selected sampling sites along the Basaseachi waterfall and its main rivers, were collected during the spring, summer, autumn, and winter seasons. Fecal and total coliform counts were determined using standard methods; the AutoScan-4 system was used for identification of isolates and the antibiotic resistance profile by challenging each organism using 21 antibiotics. Significant differences among seasons were detected, where autumn samples resulted in the highest total (p < 0.05) and fecal (p < 0.001) coliform counts, whereas the lowest total coliform counts were recorded in spring. Significant differences between sampling sites were observed, where samples from sites 6, 8, and 11 had the highest total coliform counts (p < 0.009), whereas samples from site 9 exhibited the lowest one. From the microbiological analysis, 33 bacterial isolates from 13 different sites and four sampling seasons were selected; 53% of isolates were resistant to at least one antibiotic, and 15% exhibited a multidrug resistance (MDB) phenotype. MDB were identified as Klebsiella oxytoca (two out of four identified isolates), Escherichia coli (2/7), and Enterobacter cloacae (1/3). In addition, some water-borne microorganisms exhibited resistance to cefazoline, cefuroxime, ampicillin, and ampicillin-sulbactam. The presence of these microorganisms near rural settlements suggests that wastewater is the contamination source, providing one possible transmission mechanism for diarrheal outbreaks.

Assuntos

RESUMO

A total of 63 beef offal samples (beef liver = 16; beef lung = 14; beef intestine = 9; beef tripe = 15; beef spleen = 9) from three wet markets (A, B, and C) in Selangor, Malaysia were examined for the prevalence and microbial load of Listeria monocytogenes. A combination of the most probable number and polymerase chain reaction (MPN-PCR) method was employed in this study. It was found that L. monocytogenes detected in 33.33% of the beef offal samples. The prevalence of L. monocytogenes in beef offal purchased from wet markets A, B, and C were 22.73%, 37.50% and 41.18% respectively. The density of L. monocytogenes in all the samples ranged from<3upto> 2,400 MPN/g. The findings in this study indicate that beef offal can be a potential vehicle of foodborne listeriosis.

Assuntos

RESUMO

Para evaluar la calidad bacteriológica de aguas de piscinas en la ciudad de Cumaná, estado Sucre, Venezuela, se recolectaron muestras de agua en 1 piscina pública y 4 privadas, codificadas de la A a la E; se tomaron 2 muestras semanales durante 2 meses, antes y después de la limpieza. Se determinó pH, temperatura y cloro residual; los aerobios mesófilos por contaje en placas, el Número Más Probable (NMP) para coliformes totales (CT) y fecales (CF) e identificación bacteriana por métodos convencionales. El pH osciló entre 6,8 y 7,3, la temperatura de 29 a 31ºC y el cloro residual de 0,3 a 0,5 mg/L. El contaje más elevado de bacterias mesófilas se obtuvo en B con 6x10 2 UFC/mL, y el más bajo en C con 3x10 2 UFC/mL. En relación al NMP, antes de la limpieza, el valor más alto se obtuvo en D con 2,8x10 3 CT/100 ml; E mostró el valor más alto de CF /100 ml. Después de la limpieza B mostró el valor más alto de CT ubicándose en 9,3mLx10 2 y los valores más alto de CF para D y E en 3x10 2 . Los valores de CF antes y después de la limpieza superan lo establecido por la normativa Venezolana (0 NMP/100mL). Estadísticamente, no se evidenciaron diferencias significativas entre las piscinas para CT y CF antes y después de la limpieza. Las bacterias Gramnegativas predominaron, en E (84,21%) y B (71,92%), Klebsiella pneumoniae, Escherichia coli y Pseudomonas aeruginosa. A presentó mayor número de aislados Grampositivos (44,44%), identificándose Staphylococcus epidermidis y Enterococcus faecalis. Estos resultados indican una constante contaminación bacteriana y riesgo sanitario.

To evaluate the bacteriological quality of water pools in the city of Cumaná, Sucre state, Venezuela, water samples were collected in 1 public and 4 private pools, coded A to E, respectively, 2 samples were taken weekly for 2 months before and after a pool cleaning process. We determined pH, temperature and residual chlorine, aerobic mesophilic for total plate count, the Most Probable Number (MPN) for total coliforms (TC) and fecal (FC) and bacterial identification by conventional methods. The pH in the samples ranged between 6.8 and 7.3, temperature of 29 to 31ºC and chlorine residual of 0.3 to 0.5 mg/L The highest count of aerobic mesophilic bacteria was obtained in B with 6x10 2 . CFU/mL. In relation to the MPN, before cleaning, the CT highest value was obtained in D with 2.8 x10 3 and CT/100mL, E showed the highest CF value with 6x10 2 CF/100mL. After cleaning, the results for B indicated the CT highest values, 9.3 x10 2 CT/100mL, and in D and E the results had the CF highest values, 3x10 2 CF/100 mL. CF values in the samples before and after cleaning exceed the standards established by Venezuela (0 NMP/100mL). Statistically, no significant differences were found between pools for CT and CF before and after cleaning. Gram-negative bacteria predominated, being more frequent in E (84.21%) and B (71.92%), mainly, Klebsiella pneumoniae, Escherichia coli and Pseudomonas aeruginosa. Sample A had more isolated Gram-positive (44.44%), identified as Staphylococcus epidermidis and Enterococcus faecalis. These results indicate a constant bacterial contamination and health risk.

Assuntos

RESUMO

A total of 63 beef offal samples (beef liver = 16; beef lung = 14; beef intestine = 9; beef tripe = 15; beef spleen = 9) from three wet markets (A, B, and C) in Selangor, Malaysia were examined for the prevalence and microbial load of Listeria monocytogenes. A combination of the most probable number and polymerase chain reaction (MPN-PCR) method was employed in this study. It was found that L. monocytogenes detected in 33.33% of the beef offal samples. The prevalence of L. monocytogenes in beef offal purchased from wet markets A, B, and C were 22.73%, 37.50% and 41.18% respectively. The density of L. monocytogenes in all the samples ranged from < 3 up to > 2,400 MPN/g. The findings in this study indicate that beef offal can be a potential vehicle of foodborne listeriosis.

Assuntos

RESUMO

A total of 63 beef offal samples (beef liver = 16; beef lung = 14; beef intestine = 9; beef tripe = 15; beef spleen = 9) from three wet markets (A, B, and C) in Selangor, Malaysia were examined for the prevalence and microbial load of Listeria monocytogenes. A combination of the most probable number and polymerase chain reaction (MPN-PCR) method was employed in this study. It was found that L. monocytogenes detected in 33.33% of the beef offal samples. The prevalence of L. monocytogenes in beef offal purchased from wet markets A, B, and C were 22.73%, 37.50% and 41.18% respectively. The density of L. monocytogenes in all the samples ranged from 3upto> 2,400 MPN/g. The findings in this study indicate that beef offal can be a potential vehicle of foodborne listeriosis.

RESUMO

A total of 63 beef offal samples (beef liver = 16; beef lung = 14; beef intestine = 9; beef tripe = 15; beef spleen = 9) from three wet markets (A, B, and C) in Selangor, Malaysia were examined for the prevalence and microbial load of Listeria monocytogenes. A combination of the most probable number and polymerase chain reaction (MPN-PCR) method was employed in this study. It was found that L. monocytogenes detected in 33.33% of the beef offal samples. The prevalence of L. monocytogenes in beef offal purchased from wet markets A, B, and C were 22.73%, 37.50% and 41.18% respectively. The density of L. monocytogenes in all the samples ranged from 3upto> 2,400 MPN/g. The findings in this study indicate that beef offal can be a potential vehicle of foodborne listeriosis.

RESUMO

Nine different receptacles were tested with the MPN method to determine which receptacle was most reliable and economical for MPN counts. Results showed that 96 well PCR plate were the best vessels for this type of analysis and facilitated the isolation of viable Methylotrophs.

Assuntos

RESUMO

Nine different receptacles were tested with the MPN method to determine which receptacle was most reliable and economical for MPN counts. Results showed that 96 well PCR plate were the best vessels for this type of analysis and facilitated the isolation of viable Methylotrophs.

RESUMO

Nine different receptacles were tested with the MPN method to determine which receptacle was most reliable and economical for MPN counts. Results showed that 96 well PCR plate were the best vessels for this type of analysis and facilitated the isolation of viable Methylotrophs.

RESUMO

El presente estudio evaluó el desempeño de dos sales de tetrazolio, una tradicional: INT y una de nueva generación: XTT, para estimar la densidad de microorganismos degradadores de hidrocarburos (HCs) en suelos empleando la técnica del Número Más Probable (NMP). Se analizaron 96 muestras de suelo provenientes de la Ecorregión Cafetera de Colombia. Los microorganismos fueron recuperados en agar mínimo de sales en atmósfera saturada de HCs y la capacidad degradadora fue confirmada por repiques sucesivos utilizando diesel como fuente de carbono. No se observaron diferencias significativas en los recuentos de microorganismos degradadores obtenidos con las dos sales (t de Student, p < 0,05), pero el XTT permitió mejor visualización de los pozos positivos dada la solubilidad del producto reducido, mientras que el INT produjo precipitación, debido al formazán insoluble generado, dificultando su lectura. Se obtuvo un mayor porcentaje de aislamientos empleando XTT (67%), lo cual podría indicar que el tipo de sal es determinante en la viabilidad de estas bacterias. Adicionalmente, se evaluó el límite de detección celular, las condiciones óptimas de concentración de XTT y el tiempo de incubación necesario para la detección de actividad degradadora utilizando la cepa Acinetobacter sp. El aumento en la concentración de XTT de 0,5 mM a 2 mM y el tiempo de incubación tuvieron un efecto inhibitorio y favorable respectivamente, en la recuperación de células viables, adicionalmente, límite de detección de la técnica fue de 10² UFC/ml.

The objective of this study was to evaluate the performance of two tetrazolium indicators: a traditional one: INT and a new generation one: XTT, for the estimation of hydrocarbon (HC) degrading microorganism s density using the Most Probable Number Technique (MPN). Ninety six composite soil samples were taken and analyzed from Ecorregión Cafetera Colombiana. Degrading microorganisms were recovered in minimum salt medium with saturated HC atmosphere. Degrading HC capacity of the microorganisms was confirmed by successive subcultures in the same medium using diesel as only carbon source. Counts obtained with the two salts were not significantly different (Student t test, p < 0,05) but XTT allowed an easier visualization of positive wells due to product solubility of the reduce product. A greater percentage of isolates was obtained using XTT (67%), which suggests that salt type is relevant for recovering of these microorganisms. Additionally, cell detection limit, optimal conditions of XTT concentration and incubation times for detection of activity were evaluated. This evaluation was performed by means of microplate format for hydrocarbon degrading microorganisms using Acinetobacter sp. An inhibitory effect was observed in the recovering of cultivable cells when XTT concentrations increased from 0,5 mM to 2 mM. Incubation time favored this recovering. Detection limit of this technique was established at 10² UFC/ml. Production of the XTT-formazan was positively related with initial cell concentration and negatively with incubation time.

RESUMO

A Salmonella permanece um importante problema na avicultura e, considerando os patógenos transmitidos por alimentos, aparece como um dos agentes principais em surtos de toxinfecções alimentares. Para auxiliar na avaliação de riscos em adquirir infecção alimentar via carne de frangos que sofreram cocção inadequada, ou através de contaminação cruzada a partir desses animais, torna-se importante determinar a extensão de contaminação por patógenos em carne crua. No presente trabalho, foram analisadas 180 carcaças de frangos resfriadas, adquiridas em varejos, para pesquisa de Salmonella com determinação do número de células da bactéria. Foi utilizado o método do número mais provável (NMP) nos ágares para isolamento verde brilhante com novobiocina (BGN) e xilose-lisina tergitol 4 (XLT4). Os resultados mostraram 12,2 por cento de ocorrência de Salmonella nas carcaças de frangos resfriadas e a média de NMP de Salmonella por mL, na leitura pelo ágar XLT4 foi de 2,7 células e no ágar BGN foi de 1,3 células. Os sorovares de Salmonella isolados das carcaças de frangos no estudo foram S. Enteritidis, S. Agona, S.Rissen, S. Heidelberg e S. Livingstone. A análise dos resultados demonstrou existir um número variável de células de Salmonella contaminando as carcaças de frango resfriadas que estão à venda ao consumidor.

Salmonella in poultry remains an important worldwide problem, and among foodborne pathogens, the Salmonella appears as one of the most important outbreaks agents. To assess the risks of acquiring infection via undercooked poultry or cross contamination from chickens, it is important to determine the extent of the contamination on raw poultry with this pathogen. In this study, 180 refrigerated broiler carcasses, obtained from local stores, were assessed to recover Salmonella by the most probable number (MPN) method to quantify bacterias cells onto brilliant green agar with novobiocin (BGN) and xylose lysin tergitol 4 agar (XLT4). The results showed 12,2 percent occurrence of Salmonella by conventional microbiological method from refrigerated broiler carcasses. The MPN per ml rates was 2,7 cells on XLT4 agar and 1,3 cells on BGN agar plate. The Salmonella serovars isolated from broiler carcasses were S. Enteritidis, S. Agona, S. Rissen, S. Heidelberg and S. Livingstone. Results analysis showed that could be a variable number of cells contaminating refrigerated broiler carcasses, which have been selling to the consumer.

RESUMO

We studied the peptide-degrading anaerobic communities of methanogenic reactors from two mesophilic full-scale modified upflow anaerobic sludge blanket (UASB) reactors treating brewery wastewater in Colombia. Most probable number (MPN) counts varied between 7.1 x 10(8) and 6.6 x 10(9) bacteria/g volatile suspended solids VSS (Methanogenic Reactor 1) and 7.2 x 10(6) and 6.4 x 10(7) bacteria/g (VSS) (Methanogenic Reactor 2). Metabolites detected in the highest positive MPN dilutions in both reactors were mostly acetate, propionate, isovalerate and, in some cases, negligible concentrations of butyrate. Using the highest positive dilutions of MPN counts, 50 dominant strains were isolated from both reactors, and 12 strains were selected for sequencing their 16S rRNA gene based on their phenotypic characteristics. The small-subunit rRNA gene sequences indicated that these strains were affiliated to the families Propionibacteriaceae, Clostridiaceae and Syntrophomonadaceae in the low G + C gram-positive group and Desulfovibrio spp. in the class d-Proteobacteria. The main metabolites detected in the highest positive dilutions of MPN and the presence of Syntrophomonadaceae indicate the effect of the syntrophic associations on the bioconversion of these substrates in methanogenic reactors. Additionally, the potential utilization of external electron acceptors for the complete degradation of amino acids by Clostridium strains confirms the relevance of these acceptors in the transformation of peptides and amino acids in these systems.

Assuntos

RESUMO

Introduction: Chlorination is the most widely used disinfection process for drinking water production. The formation of chlorination carcinogenic by-products and chlorine intoxication by direct manipulation in small communities has motivated the study of alternative disinfection processes. In this sense, processes of advanced oxidation (PAOs) have yielded promising results. Escherichia coli (E. coli) is customarily used as faecal bacterial indicator to determine the efficiency of disinfection processes. However, it has been shown that E. coli is less resistant to disinfection than other enteric bacteria such as Shigella  spp. and Salmonella  spp. Additionally, the viable non-culturable (VNC) state yields bacteria which are not detectable on many culture media. Objective: The main objective is to standardize a method for counting Salmonella  spp. and Shigella  spp. in specific liquid media to reliably quantify the bacteriological potential risk related to disinfection processes based on PAO. Methods: The study followed a randomized bi-factorial experimental design and the Duncan multiple comparison test. This design allowed the selection of specific liquid media to fittingly standardize the counting of Salmonella  spp. and Shigella  spp. Results: We found that the best broth for counting Salmonella typhimurium strain at different concentrations in pure and mixed cultures was the Rappaport broth RP, the EE broth also allowed growing the two bacterial species tested in this research. Nonetheless, the latter results suggest the use of additional tests for this particular broth. Discussion: There was a variation in the counting results when pure cultures were used compared to those obtained from mixtures of microorganisms. It was also noted that Salmonella typhimurium and Shigella sonnei, were recovered from minimal concentrations in both RP and EE broths, respectively. To some extent, this suggests an additional confirmative method when using the EE® broth...

Introducción: La cloración es el método más usado para desinfectar aguas de consumo. La formación de subproductos cancerígenos y las intoxicaciones por manipulación directa en pequeñas comunidades, han motivado el estudio de procesos alternativos. Los procesos de oxidación avanzada (PAOS), han arrojado resultados prometedores, utilizando el indicador bacteriano Escherichia coli (E. coli), con el método recuento en placa. Sin embargo, también se ha demostrado que E. coli es menos resistente a la desinfección que otras bacterias entéricas como Shigella y Salmonella y que estos procesos generan bacterias viables que no se cultivan durante el proceso, y no se descubren en medios sólidos. Objetivo: Estandarizar un método de recuento de Salmonella sp. y Shigella sp., en medios de cultivo líquidos especializados, que permita valorar de forma confiable el riesgo bacteriológico en procesos de desinfección PAOS. Métodos: En el presente trabajo se ensayaron y seleccionaron medios líquidos especializados, con los que se estandarizó el recuento de Salmonella sp. y Shigella sp., mediante un diseño experimental aleatorizado bifactorial y la prueba de comparaciones múltiples de Duncan. Resultados: Se encontró que el mejor caldo para recuperar a S. typhimurium a diferentes concentraciones, en cultivos puros y mezclas, fue el caldo Rappaport de Merck (RP). El caldo de enriquecimiento para entero bacterias de Oxoid (EE), permitió un buen crecimiento de las dos especies objeto de esta investigación. Lo cual sugiere el empleo de pruebas adicionales cuando se use caldo EE para NMP. Discusión: Se observó una variación en el recuento cuando se usaron cultivos puros, comparado con la obtenida a partir de mezclas de microorganismos. Sin embargo, S. typhimurium. y Shigella sonnei logran ser recuperadas de concentraciones mínimas en los caldos RP, respectivamente...

Assuntos

RESUMO

We studied the peptide-degrading anaerobic communities of methanogenic reactors from two mesophilic full-scale modified upflow anaerobic sludge blanket (UASB) reactors treating brewery wastewater in Colombia. Most probable number (MPN) counts varied between 7.1 x 10(8) and 6.6 × 10(9) bacteria/g volatile suspended solids VSS (Methanogenic Reactor 1) and 7.2 × 10(6) and 6.4 × 10(7) bacteria/g (VSS) (Methanogenic Reactor 2). Metabolites detected in the highest positive MPN dilutions in both reactors were mostly acetate, propionate, isovalerate and, in some cases, negligible concentrations of butyrate. Using the highest positive dilutions of MPN counts, 50 dominant strains were isolated from both reactors, and 12 strains were selected for sequencing their 16S rRNA gene based on their phenotypic characteristics. The small-subunit rRNA gene sequences indicated that these strains were affiliated to the families Propionibacteriaceae, Clostridiaceae and Syntrophomonadaceae in the low G + C gram-positive group and Desulfovibrio spp. in the class δ-Proteobacteria. The main metabolites detected in the highest positive dilutions of MPN and the presence of Syntrophomonadaceae indicate the effect of the syntrophic associations on the bioconversion of these substrates in methanogenic reactors. Additionally, the potential utilization of external electron acceptors for the complete degradation of amino acids by Clostridium strains confirms the relevance of these acceptors in the transformation of peptides and amino acids in these systems.

RESUMO

O aumento da produção animal trouxe como consequência a geração de grande quantidade de dejetos os quais são destinados, após tratamento, à agricultura ou coleções de superfície. Entre os microrganismos presentes nos dejetos encontram-se as salmonelas. No meio ambiente esta bactéria torna-se uma importante fonte de transmissão e, consequentemente, potencial risco à produção animal e à saúde pública sendo que seu monitoramento se faz necessário. Neste sentido, compararam-se três metodologias para a quantificação de Salmonella sp. a fim de determinar a melhor técnica de estimativa do Número Mais Provável (NMP) a ser aplicado em efluentes de sistemas de tratamento de dejetos. Em cinco amostras de efluente, inocularam-se 105 a 106 UFC de Salmonella Typhimurium e determinou-se o NMP por três diferentes metodologias (A, B e C). Comparado às contagens bacterianas do inóculo de Salmonella Typhimurium, verificou-se que o NMP médio (4,441 UFC) no método A é bastante próximo a estas (P>0,05). Por outro lado, o NMP médio observado nos métodos B (1,380 UFC) e C (3,204 UFC) diferem estatisticamente daquelas (P<0,001 e P<0,01, respectivamente). Como o método A foi aquele que demonstrou valores mais próximos de NMP às quantidades inoculadas, sugere-se a utilização desta metodologia para análise de efluentes.(AU)

The increase in animal production has increased the amount of effluents destined, most of times, to agriculture and aquatic resources. As the same of others enteric microorganisms, Salmonella is present in feces. In the environment Salmonella sp. become an important source of transmission and, consequently, a risk to animal production and public health. In this experiment, three methodologies for quantifying Salmonella sp. were compared, so as to determine the best estimation technique of the Most Probable Number (MPN) to be applied in liquid waste from effluent treatment systems. In this study, were used five water samples from an aquaculture tank. Compared to the bacterial count of the Salmonella Typhimuriums inoculum (105 a 106 CFU), it was verified that the average MPN (4.441 CFU) in method A is very similar to those counts (P>0.05). On the other hand, the average MNP observed in method B (1.380 CFU) and C (3.204 CFU) are statistically different from them (P<0.001 and P<0.01, respectively). Considering that method A was the one to present MPN values closest to the inoculated amounts, the employment of this methodology is suggested for the analysis of effluents.(AU)

Assuntos