ABSTRACT
The emergence of multi-drug resistant (MDR) bacterial strains, which are posing a global health threat has developed the interest of scientists to use bacteriophages instead of conventional antibiotics therapy. In light of an increased interest in the use of phage as a bacterial control agent, the study aimed to isolate and characterize lytic phages from sewage effluent. During the current study, bacteriophage AS1 was isolated from sewage effluent against E.coli S2. The lytic activity of phageAS1 was limited to E.coli S2 strain showing monovalent behavior. The calculated phage titer was 3.5×109 pfu/ml. PhageAS1 was stable at a wide range of pH and temperature. The maximum stability was recorded at 37ºC and pH 7.0, while showing its normal lytic activity at temperature 60ºC and from pH 5.0 to 11.0 respectively. At temperature 70ºC, phage activity was somewhat reduced whereas, further increase in temperature and decrease or increase in pH completely inactivated the phage. From the current study, it was concluded that waste water is a best source for finding bacteriophages against multi-drug resistant bacterial strains and can be used as bacterial control agent.
O surgimento de cepas bacterianas multirresistentes (MDR), que representam uma ameaça global à saúde, desenvolveu o interesse dos cientistas em usar bacteriófagos em vez da terapia convencional com antibióticos. Diante do crescente interesse no uso de fago como agente de controle bacteriano, o estudo visou isolar e caracterizar fagos líticos de efluente de esgoto. Durante o estudo atual, o bacteriófago AS1 foi isolado de efluente de esgoto contra E. coli S2. A atividade lítica de phageAS1 foi limitada à cepa E. coli S2, apresentando comportamento monovalente. O título de fago calculado foi de 3,5 x 109 ufp/ml. PhageAS1 foi estável em uma ampla faixa de pH e temperatura. A estabilidade máxima foi registrada a 37ºC e pH 7,0, enquanto mostrou atividade lítica normal em temperatura de 60ºC e pH 5,0 a 11,0, respectivamente. Na temperatura de 70ºC, a atividade do fago foi um pouco reduzida, enquanto o aumento adicional da temperatura e a diminuição ou aumento do pH inativaram completamente o fago. Com base no estudo atual, concluiu-se que a água residual é a melhor fonte para encontrar bacteriófagos contra cepas bacterianas multirresistentes e pode ser usada como agente de controle bacteriano.
Subject(s)
Bacteriophages/isolation & purification , Coliphages/isolation & purification , Escherichia coli , Bacteriophage Typing/methods , Wastewater/analysis , Phage TherapyABSTRACT
The emergence of multi-drug resistant (MDR) bacterial strains, which are posing a global health threat has developed the interest of scientists to use bacteriophages instead of conventional antibiotics therapy. In light of an increased interest in the use of phage as a bacterial control agent, the study aimed to isolate and characterize lytic phages from sewage effluent. During the current study, bacteriophage AS1 was isolated from sewage effluent against E.coli S2. The lytic activity of phageAS1 was limited to E.coli S2 strain showing monovalent behavior. The calculated phage titer was 3.5×109 pfu/ml. PhageAS1 was stable at a wide range of pH and temperature. The maximum stability was recorded at 37ºC and pH 7.0, while showing its normal lytic activity at temperature 60ºC and from pH 5.0 to11.0 respectively. At temperature 70ºC, phage activity was somewhat reduced whereas, further increase in temperature and decrease or increase in pH completely inactivated the phage. From the current study, it was concluded that waste water is a best source for finding bacteriophages against multi-drug resistant bacterial strains and can be used as bacterial control agent.
O surgimento de cepas bacterianas multirresistentes (MDR), que representam uma ameaça global à saúde, desenvolveu o interesse dos cientistas em usar bacteriófagos em vez da terapia convencional com antibióticos. Diante do crescente interesse no uso de fago como agente de controle bacteriano, o estudo visou isolar e caracterizar fagos líticos de efluente de esgoto. Durante o estudo atual, o bacteriófago AS1 foi isolado de efluente de esgoto contra E. coli S2. A atividade lítica de phageAS1 foi limitada à cepa E. coli S2, apresentando comportamento monovalente. O título de fago calculado foi de 3,5 x 109 ufp/ml. PhageAS1 foi estável em uma ampla faixa de pH e temperatura. A estabilidade máxima foi registrada a 37ºC e pH 7,0, enquanto mostrou atividade lítica normal em temperatura de 60ºC e pH 5,0 a 11,0, respectivamente. Na temperatura de 70ºC, a atividade do fago foi um pouco reduzida, enquanto o aumento adicional da temperatura e a diminuição ou aumento do pH inativaram completamente o fago. Com base no estudo atual, concluiu-se que a água residual é a melhor fonte para encontrar bacteriófagos contra cepas bacterianas multirresistentes e pode ser usada como agente de controle bacteriano.
Subject(s)
Sewage , Bacteriophages , Pakistan , Temperature , ColiphagesABSTRACT
In order to investigate the occurrence of norovirus in rivers and beaches, a total of 81 samples were tested at seven sites of Oncheon stream, Suyeong river and Gwanganri beach in Busan from January to November, 2017. To improve the detection of norovirus from sea water, we applied the inorganic cation-coated filter method which showed 48.8% ± 12.2% (n=3) and 27.4% ± 6.0% (n=3) recovery yields from river water and sea water inoculated with Norovirus, respectively. Norovirus was detected in a total of four samples (4.9%), which all were GII genotype. Norovirus GII was detected in three samples at two waste water treatment plants (WWTP) outlet and one sample at about 500 meter downstream from WWTP in both the winter and spring seasons. We also monitored fecal indicator organisms, Escherichia coli (E. coli), Enterococcus and coliphages [somatic coliphages (SC), male-specific coliphages (MSC)] to analyze the potential transmission of enteritis causative agent in dry and wet days. Bacterial influences were found at the site of the WWTP effluents in the dry days and spread further to the costal beach in the wet days. But no viral influences were found in the river downstream in both dry and wet days.
Subject(s)
Coliphages , Enteritis , Enterococcus , Escherichia coli , Genotype , Korea , Methods , Norovirus , Rivers , Seasons , Seawater , Wastewater , WaterABSTRACT
ResumenLa calidad del agua de consumo es una de las preocupaciones más grandes a las que se enfrentan los entes de salud. En Costa Rica, a pesar de la buena calidad de las fuentes de agua y del agua de consumo, se siguen registrando numerosos casos de diarrea anualmente. En este estudio se realizó un análisis de indicadores de contaminación virales y bacterianos, en dos comunidades del Valle Central con acueducto propio. Se analizaron en total 24 muestras de agua por cada comunidad, durante un año, 12 en la fuente de agua y 12 en el agua tratada. La frecuencia de diarreas en cada comunidad fue comparada con la calidad microbiológica del agua consumida, encontrándose ausencia de indicadores bacterianos en muestras de agua tratada, mientras que la presencia de indicadores virales en el agua de consumo (con cloro residual) se relaciona con un incremento en el número de casos de diarreas, adicionalmente se analizó el comportamiento de las diarreas de acuerdo a la precipitación promedio con el fin de observar posibles patrones de estacionalidad. Estos hallazgos respaldan la necesidad de ampliar el monitoreo de calidad microbiológica del agua con otro tipo de indicadores de contaminación que correlacionen mejor con otros agentes patógenos de transmisión hídrica, principalmente en época seca, periodo en que se observan más casos de diarrea.
AbstractThe quality of potable water is one of the most important issues of public health. In Costa Rica, in spite of having good sources of water and good quality of water for consumption, there continues to be a significant number of diarrhea cases annually. In this investigation, viral and bacterial analyses of indicators of contamination were conducted in two rural communities with their own aqueducts in the Central Valley of Costa Rica. Twenty-four samples were taken from each community during the year; 12 from the water sources and 12 from the treated waters. The frequency of diarrhea in each community was compared to the microbiological quality of the water being consumed, noting an absence of bacterial indicators in samples of treated water, while the presence of viral indicators in the water (with residual chlorine) were associated with an incremental increase in the number of cases of diarrhea. The analysis also included measurements of average monthly rainfall with the aim of observing possible associations between seasonal conditions and the incidence of diarrhea cases. These findings indicate the need to increase the monitoring of the microbiological quality of the water with other types of indicators of contamination that correlate better with other pathogens transmitted by water, especially in the dry seasons when a greater number of cases of diarrhea are observed.
Subject(s)
Humans , Water Pollution , Water Chlorination , Domestic Water Consumption , Sanitation , Coliphages , Costa Rica , Diarrhea , ColiformsABSTRACT
Introducción: En el presente artículo se propone una metodología rápida y sencilla para determinar colifagos sómaticos en las diferentes etapas del tratamiento de agua de una planta del Nordeste Colombiano, con el fin de verificar la calidad del proceso de potabilización. Materiales y métodos: Se empleó la técnica de filtración por membrana para obtener el contenido fágico y posteriormente se cuantificó la presencia de los virus a través de la metodología de capa simple usando agar tripticasa de soya modificado. Resultados: El 88% de las muestras de agua analizadas resultaron ser positivas en alguna de las etapas del proceso de potabilización. La presencia de fagos aumentó en época de lluvias con recuentos máximos de 1310 UFP/100mL en la etapa de captación del agua y de 2,5 UFP/100mL en la etapa de cloración. La prueba no-paramétrica Chi cuadrado de homogeneidad en distribución corroboró estadísticamente la igualdad en distribución de las muestras positivas encontradas en cada una de las etapas de potabilización (p>5%) pues el muestreo fue fijado por indicador. Conclusión: La metodología empleada permitió en tan solo 12 horas determinar la presencia de colifagos somáticos en las diferentes etapas de tratamiento de agua de la planta objeto de estudio. Además, se comprobó la elevada resistencia de estas nanomáquinas naturales a los procesos de desinfección, que mostraron persistencia en etapas de almacenamiento y distribución, especialmente en época de lluvias.
Introduction: In this article a quick and simple method is proposed to determine somatic coliphages in the different stages of water treatment in a plant in the northeast of Colombia, in order to verify the quality of the treatment process. Materials and methods: The technique of membrane filtration was used to get the phage content and subsequently through the methodology of single layer using tryptic soy agar modified, the presence of the virus was quantified. Results: 88% of the water samples analyzed were found to be positive in any of the stages of purification. The presence of phages increased during the rainy season with maximum counts of 1310 UFP / 100 mL at the stage of uptake of water and 2.5 UFP / 100 mL in the chlorination stage. Non-parampetrica Chi square homogeneous distribution test confirmed statistically equal distribution of positive samples found in each of the stages of purification (p> 5%) because the sample was determined by indicator. Conclusion: The methodology allowed to determine the presence of somatic coliphages at different stages of water treatment in the plant under study in only 12 hours. In addition, the high resistance of these natural nanomachines to the processes of disinfection was found, which showed persistence in warehousing and distribution stages, especially in the rainy season.
Subject(s)
Bacteria , Water , Coliphages , Water Purification , ColiformsABSTRACT
Con el fin evaluar el campo de aplicación potencial de una bacteria ácido láctica y de sus metabolitos, se realizó la cinética de la actividad antimicrobiana de W. confusa y de sus metabolitos contra E. coli, y K. pneumoniae, dos patógenos causantes de enfermedades transmitidas por alimentos. La producción de W. confusa se realizó por fermentación discontinua en sustrato comercial MRS. Se realizaron tres fermentaciones durante 6 horas, sin aireación, agitación continúa 33°C y 100 rpm. Cada hora de fermentación se separaron tres sustancias biológicas, W. confusa con sus metabolitos (W+W10b), células de W. confusa libres de metabolitos (W) y metabolito (W10b) y se midió la actividad antimicrobiana contra los patógenos E. coli, y K. pneumoniae. Se encontraron diferencias estadísticas significativas entre tratamientos y tiempo de fermentación. Para E. coli el tratamiento W presentó la mayor actividad antimicrobiana, la cual se obtuvo entre la cuarta y sexta hora de fermentación (2.45 cm de diámetro promedio de inhibición). Para K. pneumoniae, los tratamientos W y W+W10b presentaron actividad antimicrobiana entre la cuarta y quinta hora de fermentación, sin diferencia significativa entre ellos. W. confusa y el metabolito W10b demostraron poseer capacidad antimicrobiana contra E. coli y K. pneumoniae, lo cual sugiere que W. confusa y W10b podrían utilizarse como alternativa de bioconservación o bioprotección de alimentos frescos y procesados, para alimentación humana y animal; y podría convertirse en una alternativa al uso de antibióticos para enfermedades causadas por E. coli y K. pneumoniae.
The kinetic of antimicrobial activity of Weissella confusa and their metabolites against E. coli, and K. pneumoniae, (two pathogens causing foodborne illness) was evaluated, in order to know the possible use in food processing. W. confusa was produced by batch fermentation using MRS commercial substrate. Three fermentations, of 6 hours at 33 °C, without aeration, stirring continuously (100 rpm) were performed. Every hour of fermentation, three biological substances, W. confusa with their metabolites (W + W10b), W. confusa free cells metabolites (W), and metabolite (W10b) were separated, and subsequently the antimicrobial activity against pathogenic E. coli and K. pneumoniae was measured. Statistically significant differences between treatments and fermentation time were found. Treatment (W) against E. coli, showed the greatest antimicrobial activity, it was obtained between the fourth and sixth hours of fermentation (2.45 cm diameter average inhibition). In treatments W and W + W10b against K. pneumoniae, statistically significant differences between them were not found. The antimicrobial activity was shown between the fourth and fifth hour of fermentation. W. confusa and W10b have antimicrobial activity against E. coli and K. pneumoniae, suggesting that W and W10b could be used as an alternative to biopreservation or bioprotection of fresh and processed food for human and animal consumption, and could become an alternative to antibiotics used for diseases caused by E. coli and K. pneumoniae.
Subject(s)
Anti-Infective Agents , Eating , Escherichia coli , Food , Food Analysis , Klebsiella pneumoniae , Weissella , Biotechnology , Coliphages , Escherichia coli Proteins , KlebsiellaABSTRACT
The appearance of enteric disease outbreaks associated with the use of waters considered bacteriologically suitable, calls for the search of new and more precise indicators. Samples of estuarine water were collected in order to quantify E. coli and E. coli ATCC 13706 somatic coliphages and to compare the usefulness of the latter to detect faecal contamination when the concentration of traditional indicators is not quantifiable. Statistical analyses suggested the division of sampling sites into two groups: group I and group II, according to the minor or major level of faecal pollution respectively registered. In group II a high correlation between the coliphages and E. coli (r: 0.73 p<0.01) was detected. E. coli always exceeded coliphage abundance. In group I, this relationship was statistically significant (r: 0.55 p< 0.05), coliphage counts were higher than those of E. coli and were detected in the absence of the latter. In summary, the use of E. coli ATCC 13706 somatic coliphages is proposed as a complementary tool for the diagnosis of the level of faecal contamination of estuarine waters, especially in areas of low pollution.
La aparición de brotes de enfermedades víricas entéricas asociadas al uso de aguas bacteriológicamente aptas impone la búsqueda de nuevos y más precisos indicadores de contaminación. Se recolectaron muestras de agua estuarina, donde se cuantificaron simultáneamente la bacteria E. coli y los colifagos somáticos de E. coli ATCC 13706, a fin de evaluar la utilidad de estos últimos para detectar contaminación fecal cuando la concentración de los indicadores tradicionales no es cuantificable. Los resultados estadísticos sugirieron la división de las estaciones de muestreo en dos grupos, I y II, de acuerdo con el menor o mayor nivel de contaminación fecal registrado, respectivamente. En el grupo II se detectó una alta correlación entre los recuentos de colifagos y de E. coli (r: 0,73 p<0,01). Asimismo, en este grupo la abundancia de E. coli siempre superó a la de colifagos. En el grupo I la correlación fue estadísticamente significativa (r: 0,55 p < 0,05), pero de mediana magnitud, los recuentos de colifagos superaron a los de E. coli, y éstos fueron detectados aun en ausencia de la bacteria. En conclusión, los colifagos somáticos de E. coli ATCC 13706 serían una herramienta accesoria en el diagnóstico del nivel de contaminación fecal de aguas estuarinas, sobre todo en áreas donde ésta es baja.
Subject(s)
Coliphages/isolation & purification , Feces/microbiology , Fresh Water/microbiology , Water Microbiology , ArgentinaABSTRACT
Escherichia coli es el agente etiológico enterobacteriano más común causante de enfermedades diarreicas en lapoblación infantil. Por este motivo se estudió la transferencia por conjugación de genes plasmídicos de resistencia a antibióticos de bacterias E. coli provenientes de heces de niños menores de 3 años con procesos diarreicos que asistieron al laboratorio clínico delHospital materno infantil durante abril y diciembre del 2003. Se analizó el antibiograma de 44 cepas de E. colique presentó altos porcentajes de resistencia (Amoxicilina 95.55%, cotrimoxazol 68.88%, cloranfenicol51.11%). Por otra parte, las asociaciones más comunes de antibióticos fueron amoxicilina-cotrimoxazol (65%), y amoxicilina-cotrimoxazol-cloranfenicol (47,73%). Los experimentos de conjugación presentaron frecuencias entre 10-5 a 1 0-7, siendo de mayor valor para latransferencia de amoxicilina y menor para la amikacina. Los porcentajes de resistencia y las frecuencias deconjugación demuestran que la mayoría de los genes de resistencia son capaces de ser transferidos por conjugación. Lo que implica probablemente que muchosde estos genes están localizados en elementos genéticos como plásmidos y transposones.
Subject(s)
Child , Adhesins, Escherichia coli/analysis , Coliphages/isolation & purification , /enzymologyABSTRACT
A finales del año 2001 y comienzos del 2002 se realizó un estudio con el fin de determinar la prevalencia de colífagos en el agua del acueducto de la vereda La Cabaña, Manizales, Caldas, Colombia que abastece los sectores de La Pava, El Chuzo, La Cabaña y La Playa, para relacionar el grado de contaminación fecal del agua. Para el desarrollo del trabajo se utilizó como prueba diagnóstica el método de detección de colífagos ARCAT (A Rapid Coliphage Analysis Technique). Los resultados obtenidos en 68 muestras compuestas de agua de 136 viviendas del sector (una muestra de 200 ml por cada dos casas), mostraron una alta prevalencia para colífagos (97 por ciento); encontrándose un recuento decolífagos entre 0 95 PFU / 100 ml. Las precipitaciones resultaron ser uno de los factores más importantes que influyeron en este estudio.
At the end of 2001 and beginnings 2002 a study was carried for detection of coliphages prevalency in the aqueduct water of the La Cabaña village, Manizales, Caldas, Colombia that supplies the sectors of La Pava, El Chuzo, La Cabaña and La Playa, for relationship the contamination fecal grade water. For the development of the research the method of coliphage detection ARCAT (A Rapid Coliphage Analysis Technique) was used as the diagnostic test. The results obtained in 68 samples of water of 136 housings of the sector showed a high prevalency for coliphage (97 percent); finding a coliphage count in 0 - 95 PFU / 100 ml. the precipitations turned out to be one of the most important factors that influenced in this study.
Subject(s)
Animals , Humans , Coliphages , Colombia , Prevalence , Vulnerable Populations , WaterABSTRACT
Foi realizado estudo comparativo em condições experimentais similares, entre hipoclorito de sódio e ácido peracético na desinfecção de água com elevada concentração de matéria orgânica. O conteúdo de carbono orgânico dissolvido (COD) variou de 4,652 a 30,13 mgC/L para a água de estudo bruta e após a desinfecção esses valores variaram de 5,105 a 26,16 mgC/L para os ensaios com cloro e de 15,89 a 32,78 mgC/L para os ensaios com ácido peracético. O desempenho dos dois desinfetantes foi avaliado segundo a inativação de três microrganismos indicadores, Escherichia coli ATCC 11229, colifagos e Clostridium perfringens ATCC 13124 que eram previamente cultivados e inoculados à água no momento do experimento. As concentrações aplicadas de cloro e ácido peracético foram de 2,0; 3,0; 4,0 e 5,0 mg/L e os tempos de contato de 5, 10, 15 e 20 minutos. Para 3,0 mg/L de cloro aplicado, obteve-se 3 log de inativação de E. coli em 20 minutos de contato, 2,92 log de inativação de fagos em 10 minutos e 2 log de inativação de C. perfringens em 15 minutos. Os resultados dos ensaios de desinfecção com ácido peracético indicaram efetiva inativação dos microrganismos indicadores empregados, mesmo na presença de elevada concentração de matéria orgânica. Para 5,0 mg/L de ácido peracético aplicado e 15 minutos de contato, inativações de E. coli maiores que 6 log, de fagos maiores que 5 log em 20 minutos e de C. perfringens maiores que 4 log em 10 minutos de contato foram alcançadas.
Subject(s)
Wastewater , Clostridium perfringens , Coliphages , Escherichia coli , Peracetic Acid , Sodium Hypochlorite , Water DisinfectionABSTRACT
This study was carried out to assess the sludge treatment processes applied at the 6[th] October wastewater treatment plant [WWTP], Giza, Egypt. The applied processes included aerobic digestion followed by gravity thickening, filter-pressing and drying beds [in emergency cases]. Bacteriological, virological and parasitological evaluation was carried out. Results showed that aerobic digestion removed two log units of total and faecal coliforms and one log unit of Escherichia coli [E. coli] and feacal streptococci. The removal percentages of coliphage and enteroviruses after aerobic digestion were 97.0 and 58.3%, resectively. The salmonellae disappeared from sludge after aerobic digestion. Qualitative and quantitative decrease in helminth ova [Ascaris, Trichuris, Trichostrongylus, Taenia and Hymenoleois] was observed after aerobic digestion and thickening stages. An average decreae of 4 log units for total and faecal coliforms, 3 log units for each of faecal streptococci and coliphage and 2 log units for E. coli through sludge treatment process was observed. Enteroviruses, helminth ova and enteric protozoa were completely eliminated from sludge after 6 months in drying beds. The loads of faecal coliform, E coli, faecal streptococci and coliphage in the dried sludge were 6.5 x 10[2], 1.6 x10[2], 4.5 x 10[2], 4.56 x 10[2] cfu and 8.5 x 10[1] pfu/g, respectively. Microbiological quality of the final treated sludge complied with the regulations of Untied States Environmental Protection Agency
Subject(s)
Waste Management , Water Pollution , Sewage/parasitology , Sewage/virology , Escherichia coli , Streptococcus , Salmonella , Ascaris , Trichuris , Trichostrongylosis , Taeniasis , ColiphagesABSTRACT
Neste trabalho são apresentados resultados da aplicação da fotocatálise heterogênea utilizando dióxido de titânio imobilizado sobre placa de vidro, irradiado por luz solar, para desinfecção de esgoto sanitário secundário. Utilizou-se o efluente de um reator anaeróbio/aeróbio com leito expandido de carvão ativado que trata o esgoto do Campus da USP/São Carlos, e também de contribuições domésticas. Os experimentos foram do tipo batelada, com tempo de recirculação de 4 horas. As vazões estudadas foram 15, 22,5 e 30 L/h. Foram avaliadas as remoções de matéria orgânica (DQO e COT) e a inativação de microrganismos indicadores de contaminação fecal (coliformes totais, E. coli, Clostridium perfringens e colifagos).
Subject(s)
Wastewater , Clostridium perfringens/isolation & purification , Coliphages/isolation & purification , Wastewater Treatment Plants/methods , Wastewater Characteristics , Water Purification , Water DisinfectionABSTRACT
Twenty six thermotolerant strains resistant to high levels of chromium (50-250 microg/ml) were isolated from treated tannery effluent. They were also found resistant to multiple heavy metals and antibiotics. Majority of them were resistant to copper and bacitracin. Nine strains representing different resistance patterns were selected for plasmid profile and conjugation studies. Agarose gel electrophoresis results revealed that 6 strains harboured a single plasmid, whereas 3 strains exhibited 2 plasmid bands. Among antimicrobials, co-trimazole and bacitracin and among metals, Cu2+, Cd2+, Zn2+ and Ni2+ resistance were transferred most frequently at variable rates. However, chromium resistance was transferred in 6 strains with a frequency ranging 19-49x10(-2). Resistance to Co2+ and Hg2+ did not transfer under environmental conditions. Among the nine strains, three were found predominantly uropathogenic Escherichia coli (UPEC) serotype 04, whereas two strains were untypable. In addition, 4 transconjugants also showed a positive result after serotyping.
Subject(s)
Anti-Bacterial Agents/pharmacology , Chromium/toxicity , Coliphages/isolation & purification , Conjugation, Genetic , Drug Resistance, Microbial , Escherichia coli/drug effects , Microbial Sensitivity Tests , R Factors , Serotyping , Tanning , Temperature , Water Pollutants, Chemical/toxicityABSTRACT
Constructed wetland and detention pond as a treatment system was applied for stormwater management in two adjacent areas in western Sydney. F-specific RNA and somatic coliphages were used as a model for assessing two systems for removal of viral pollution, fate, behavior and survival of viruses in the sediment. Water samples were collected weekly in sterile containers and sediment samples were collected three times using a box dredge sampler via a boat at the inlet, middle and outlet areas of the systems. F-specific RNA coliphages were enumerated using the double layer plaque assay [ISO 1995] with Salmonella typhimurium WG49 as a host. Survival test continued 28 d for each sub-sample. Viral removal in constructed wetland was more effective than the detention pond system. Survival of somatic coliphages in the inlet and middle of the systems was similar. Slope of declining for outlet of two systems was very slow and completely stable in whole of test duration. Constructed wetland may offer an attractive alternative to stormwater management for reducing the load of disease-causing viruses to the receiving waters
Subject(s)
Coliphages , RNA , Survival Analysis , VirusesABSTRACT
Evidence from the scientific literature suggests that coliform bacteria are not adequate indicators for fecal contamination, and the need has been expressed for development of rapid, accurate, and cost-effective techniques for determining the bacteriological quality of water. One alternative has been the use of coliphage methods. The objetive of the present study was to evaluate bacteriological water quality of sewage treated with fecal coliforms and coliphage. Water samples were collected from three stations: 1) influent, 2) middle, and 3) effluent at the Antofagasta activated sludge treatment plant. Coliform bacteria were determined using the MPN technique, and coliphage enumeration as described by Isbister et al., (1983). Escherichia coli ATCC 13706 was used as the host strain. The counts of both organisms decreased in a similar way through the different treatment steps with little variation over a one-year period. Coliphage numbers were lower than the bacteria by about one log. After the sewage treatment chlorination step the coliphage number was higher than the fecal coliforms. These differences showed that the coliphage was more resistent to chlorine than the fecal coliforms. The results suggested than the coliphage could be used as an alternate indicator in evaluation of bacteriological quality of treated sewage effluent.
Fuertes evidencias sugieren que las bacterias coliformes no son indicadores adecuados de contaminación fecal. Hay una gran necesidad por el desarrollo de una técnica más rápida, acuciosa y de bajo costo para determinar la calidad bacteriológica del agua. Los colifagos parecen ser una excelente alternativa. El objetivo de este estudio fue evaluar la calidad bacteriológica de aguas servidas tratadas por medio de los coliformes fecales y colifagos. Muestras de aguas fueron recolectadas de tres estaciones: afluente, en el medio y efluente en la planta de tratamientos de Antofagasta por lodos activados. Las bacterias coliformes fueron determinadas por la técnica del NMP y la enumeración de colifagos, como describe Isbister y col (1983). Escherichia coli ATCC 13706 fue usada como cepa huésped. Los recuentos de ambos microorganismos disminuyeron en forma similar a lo largo de las diferentes etapas del tratamiento con variaciones pequeñas durante un año, siendo el número de colifagos más bajos que los coliformes fecales en un log. Al final del tratamiento de las aguas servidas, etapa de cloración, los números de los colifagos fueron más altos que los coliformes fecales. Estos resultados sugieren que los colifagos pueden ser usados como un indicador alternativo para la evaluación de la calidad bacteriológica de las aguas tratadas.
Subject(s)
Coliphages/isolation & purification , Coliforms/analysis , Water Microbiology , Activated Sludges , Bacteriological Techniques , Chile , Reference Values , Water PurificationABSTRACT
A study was carried out to assess the changes in the population densities of certain microbial groups of hygienic significance throughout the successive steps of treatment in Virginia Key Wastewater Plant in Miami, Florida. Samples were taken from raw sewage, oxygenated tanks, settling tanks and chlorinated effluent. Total count, total coliform, Streptococcus faecalis, Aeromonas hydrophila and coliphage increased or remained unchanged after oxygenation but they sharply decreased in settling and chlorination tanks were more than 99% reduction in counts initially present was observed. A. hydrophila and coliphage were still detected in the final effluent. With respect to the last stages of treatment till the production of dewatered sludge, all tested groups of microorganisms attained their highest values in the effluent of concentration tanks. They decreased throughout the steps of treatment till the dewatered sludge to attain 106-105 cfu/g for total counts and total coliform as well as 104 cfu/g for A. hydrophila and S. faecalis and 103 pfu/g for coliphage. An experiment was conducted to study the efficiency of gamma radiation in reducing the microbial load in the chlorinated effluent and dewatered sludge. In the chlorinated effluent, total counts, S. faecalis and coliphage were eliminated with 2 kGy while 1 kGy was sufficient to eradicate total coliform and A. Hydrophila. Regarding the dewatered sludge, a dose of 6 kGy was quite sufficient to decrease total counts from 6x105 to few cells/g. Whereas, total coliform, S. Faecalis and A. hydrophila could not be detected after irradiation with 2,4 and 1 kGy respectively. Coliphage was eliminated after irradiation with 6 kGy. Another experiment was carried out to compare the effect of gamma radiation with that of electron beam on microbial groups in chlorinated effluent. At any given dose of radiation, gamma rays proved to be of more lethal than electron beam for all types of organisms
Subject(s)
Gamma Rays , Indicators and Reagents , Coliphages/radiation effects , Enterococcus faecalis/radiation effects , Aeromonas hydrophila/radiation effectsABSTRACT
Las colicinas son sustancias proteicas con actividad bactericida, producidas por miembros de la familia Enterobacteriaceae y que presentan un espectro de acción limitado únicamente a especies de la misma familia. El estudio de las colicinas data desde 1925, aunque su primera clasificación, basada en sus propiedades químicas, físicas y biológicas, fue la realizada en 1948 por Frédériq. Posteriormente, Davies y Reeves en 1975 las dividieron en dos grandes grupos: A y B, de acuerdo con los diferentes patrones de resistencia obtenidos para una serie de mutantes resistentes a cada una de las colicinas conocidas. Se demostró que las mutatantes de resistencia a colicinas del grupo A nunca son resistentes a colicinas del grupo B, y viceversa. Actualmente se han hecho avances notables en el conocimiento del modo de acción de las colicinas. En efecto, se ha determinado que las colicinas pueden actuar en tres formas diferentes: 1) aquellas que actúan específicamente en la membrana celular, induciendo canales dependientes de diferencias de voltaje; 2) las que presentan actividad endonucleolítica, y 3) el caso especial de la colicina M, que es capaz de inhibir específicamente la síntesis de mureína. En general, se ha determinado que el efecto bactericida de las colicinas en las células sensibles precisa de tres partes de la molécula: 1) la unión específica de la colicina con su receptor en la membrana celular externa, que requiere de la parte central de la proteína; 2) la parte -NH2 terminal de la colicina, la cual es necesaria para que ésta atraviese la membrana celular, y 3) la parte -COOH terminal, que es indispensable para el reconocimiento de la colicina con su blanco específico. Las colicinas están codificadas en plásmidos; se han localizado varios de los genes involucrados tanto en la producción de la colicina, como de la proteína de liberación, así como de la proteína que le confiere inmunidad a la célula portadora de dicho plásmido. Los genes estructurales que codifican para dichas proteínas están bajo el control del regulón SOS, que se encuentra reprimido por la proteína LexA. El conocimiento de los plásmido colicinogénicos (factores col+) ha facilitado el desarrollo de la biotecnología, debido a que son multicopia y autorreplicables, por lo que son empleados como vectores de clonación en diferentes estudios del DNA. No obstante el uso más frecuente del conocimiento del fenómeno de colicinogenia en diferentes partes del mundo, ha sido en estudios epidemiológicos Así, se ha establecido que la frecuencia de cepas colicinogénicas es mayor entre los aislados de individuos enfermos, en comparación con los obtenidos de individuos sanos de la misma especie y de la misma ubicación geográfica. Por su parte, la colicina V ha sido ampliamente reconocida como un marcador de patogenicidad entre cepas de Escherichia coli, mientras que la colicina E1 se ha identificado frecuentemente entre sujetos sanos. Por otro lado, a pesar de que las colicinas se han detectado desde hace más de setenta y cinco años, aún no se conocen los efectos biológicos que puedan tener sobre el hospedero humano portador de cepas colinogénicas. Consecuentemente, para establecer si las colicinas pueden conferir alguna ventaja no sólo a las cepas productoras, sino también al hospedero, se requieren aún numerosos trabajos de investigación biomédica
Subject(s)
Cell Membrane , Colicins/biosynthesis , Colicins/chemistry , Colicins/classification , Colicins/genetics , ColiphagesABSTRACT
Foram submetidas às contagens de colifagos, coliformes totais, coliformes fecais, e de estreptococos fecais, 104 amostras de água colhidas de 8 poços rasos localizados na área urbana do Município de Jaboticabal, SP, Brasil, com a finalidade de avaliar as condiçöes higiênico-sanitárias e de verificar as correlaçöes existentes entre o número de colifagos e o de bactérias indicadoras de poluiçäo fecal. Os resultados obtidos evidenciaram a ocorrência de 96 (92,3 por cento) amostras fora dos padröes bacteriológicos de potabilidade estabelecidos pelo Ministério da Saúde, mostrando ser precárias as condiçöes higiênico-sanitárias das aguás analisadas. Os achados evidenciaram a inexistência de correlaçäo entre o número de colifagos e os números de bactérias indicadoras de poluiçäo fecal
Subject(s)
Water Pollution , Coliphages/isolation & purification , Water Quality Criteria , Brazil , Enterobacteriaceae/isolation & purification , Drinking Water , Water Microbiology , Water WellsABSTRACT
A two step hybridization procedure was developed to detect the presence of hepatitis B virus in blood samples using bacteriophage M13 radiolabelled DNA as probe. During the first step of hybridization, single-stranded bacteriophage M13 tg 130 DNA, with 3.2 kb HBV DNA cloned into it, was hybridized to target HBV DNA immobilized on nitrocellulose membrane filter. In the second step of hybridization, M13 DNA annealed to HBV target is detected with the help of double stranded form of M13 DNA. The assay offers minimum 4- to 6-fold higher sensitivity in comparison to single-step conventional hybridization assays. Additionally M13 DNA offers itself as universal probe.
Subject(s)
Coliphages/genetics , DNA Probes , DNA Restriction Enzymes , DNA, Viral/genetics , Genetic Techniques , Hepatitis B/diagnosis , Hepatitis B virus/genetics , Humans , Nucleic Acid HybridizationABSTRACT
Foram analisadas amostras de águas subterrâneas de três cemitérios localizados em áreas geologicamente distintas de Säo Paulo e de Santos, Brasil, com relaçäo às condiçöes higiênicas e sanitárias. Para as primeiras foram considerados os coliformes totais, bactérias heterotróficas, microrganismos proteolíticos e lipolíticos. Para as sanitárias foram pesquisados coliformes fecais, estreptococos fecais, clostrídios sulfito redutores, colifagos e salmonelas. Verificou-se que as águas näo apresentaram condiçöes higiênicas satisfatórias e, em alguns casos, foram encontrados níveis altos de nitrato (75,7 mg/l). A detecçäo de níveis mais elevados de estreptococos fecais e de clostrídios sulfito redutores em relaçäo aos coliformes fecais, na maior parte das amostras, parece mostrar que os dois primeiros indicadores seriam mais adequados para avaliaçäo das condiçöes sanitárias deste tipo de água. Foi detectada Salmonella apenas em uma amostra e näo foram detectados colifagos. Na análise estatística, foram encontradas correlaçöes significantes entre três indicadores de poluiçäo fecal assim como entre as contagens em placas de bactérias heterotróficas aeróbias, anaeróbias e lipolíticas. Foi observada uma relaçäo direta entre a deterioraçäo da qualidade da água e as condiçöes geológicas e hidrogeológicas do ambiente estudado, devendo este fator ser considerado para o planejamento e implantaçäo de cemitérios