Direct electron microscopy study on the morphological diversity of bacteriophage populations in lake plusssee

Direct electron microscopy of bacteriophages adsorbed to a carbon film without prior enrichment by specific host strains or concentration by physical or chemical methods was used to study the morphological diversity of natural bacteriophage assemblages in a North German lake. All samples contained a mixture of morphologically different tailed viruses, which were regarded as bacteriophages. Most of them had isometric heads and long noncontractile tails, belonging to morphotype B1 (Siphoviridae). In addition, members of morphotypes A1 (Myoviridae), B2 (Siphoviridae with elongated heads), and C1 (Podoviridae) were present in lower numbers. Only one cubic virus was detected, while no filamentous or pleomorphic phages were found. Up to 11 different phages per sample, and a total of 39 phages when all samples were considered together, could be distinguished by morphological criteria. The total number of phages was estimated to be on the order of 10/ml.     

Morphology of Pasteurella multocida bacteriophages

Twenty-one tailed phages with icosahedral heads belong to the Myoviridae, Siphoviridae, and Podoviridae families and to four morphological types. Type AU, with 10 phages, has a contractile tail and is morphologically identical with coliphage P2. Lysates contain contracted tail sheaths assembled end-to-end and abnormal structures with long tails and multiple tail sheaths. Types C-2 and 32, with one and three phages, respectively, have long, noncontractile tails. Type 22 includes seven phages, has a short tail, and resembles coliphage T7. Our results agree with previous biological data and suggest that types AU, C-2, 32, and 22 correspond to four different phage species.     

Coliforms as a measure of sewage contamination of the River Zambezi

The effect of releasing untreated sewage from Victoria Falls Town into the Zambezi river was determined by bacteriological examination of water samples collected upstream of Victoria Falls and for 22 km downstream. Most probable numbers of faecal coliforms and Escherichia coli were estimated. Water upstream of the falls, on the Zimbabwe side of the river, contained between seven and 130 E. coli per 100 ml. This section of the river was free from major sources of faecal pollution. Below the falls, but before the Victoria Falls Town sewage outfall, numbers of E. coli were between 1.8 X 10(2) and 1.4 X 10(4)/100 ml, indicating the existence of a sewage discharge other than that from Victoria Falls Town. The river was also highly polluted from the Victoria Falls Town sewage outfall to a point 18.6 km downstream. The highest E. coli count was 3.3 X 10(4)/100 ml and declined slowly to 1.4 X 10(3)/100 ml 18.6 km downstream of the outfall.     

Coliforms as a measure of sewage contamination of the River Zambezi

The effect of releasing untreated sewage from Victoria Falls Town into the Zambezi river was determined by bacteriological examination of water samples collected upstream of Victoria Falls and for 22 km downstream. Most probable numbers of faecal coliforms and Escherichia coli were estimated. Water upstream of the falls, on the Zimbabwe side of the river, contained between seven and 130 E. coli per 100 ml. This section of the river was free from major sources of faecal pollution. Below the falls, but before the Victoria Falls Town sewage outfall, numbers of E. coli were between 1.8 × 10² and 1.4 × 10⁴/100 ml, indicating the existence of a sewage discharge other than that from Victoria Falls Town. The river was also highly polluted from the Victoria Falls Town sewage outfall to a point 18.6 km downstream. The highest E. coli count was 3.3 × 10⁴/100 ml and declined slowly to 1.4 × 10³/100 ml 18.6 km downstream of the outfall.     

Occurrence and densities of bacteriophages proposed as indicators and bacterial indicators in river waters from Europe and South America

AIMS: To evaluate the feasibility of bacteriophages as a complementary tool for water quality assessment in surface waters from different parts of the globe. METHODS AND RESULTS: Faecal coliform bacteria, enterococci, spores of sulphite-reducing clostridia, somatic coliphages, F-specific RNA bacteriophages and bacteriophages infecting Bacteroides fragilis were determined by standardized methods in raw sewage and in 392 samples of river water from 22 sampling sites in 10 rivers in Argentina, Colombia, France and Spain, which represent very different climatic and socio-economic conditions. The results showed that the indicators studied maintained the same relative densities in the raw sewage from the different areas. Classifying the river water samples according to the content of faecal coliform bacteria, it can be observed that the relative densities of the different bacterial indicators and bacteriophages changed according to the concentration of faecal coliform bacteria. There was a relative increase in the densities of all groups of bacteriophages and sulphite-reducing clostridia with respect to faecal coliforms and enterococci in the samples with low counts of faecal coliform bacteria. CONCLUSIONS: The numbers of bacterial indicators and bacteriophages were similar in the different geographical areas studied. Once released in rivers, the persistence of the different micro-organisms differed significantly. Bacteriophages and spores of sulphite-reducing clostridia persisted longer than faecal coliforms and enterococci. SIGNIFICANCE AND IMPACT OF THE STUDY: Bacteriophages in river water samples provide additional information to that provided by bacteria about the fate of faecal micro-organisms in river water. The easy, fast and cheap methods for phage determination are feasible both in industrialized and developing countries.     

Human norovirus occurrence and diversity in the Llobregat river catchment, Spain

Human noroviruses (NoV) were quantified and characterized in an 18 month survey conducted along the Llobregat river catchment in Spain. Sample types included freshwater, untreated and treated wastewater and drinking water. High NoV genome copy numbers were reported, reaching up to 10(6) l(-1) and 10(9) l(-1) in freshwater and raw sewage respectively. In both types of samples, GII NoV genome copies outnumbered those of GI, although without significance. All samples of semi-treated and treated drinking water were negative for NoV. A clear seasonality of NoV occurrence was observed both in river water and sewage samples, with significantly higher genome copy numbers in the cold than in the warm months period. Mean NoV log reduction rates after biological treatment of sewage were 2.2 and 3.1 for GI and GII respectively. A total of 77 NoV strains isolated in the Llobregat river catchment could be phylogenetically characterized, 44 belonging to GI and 33 to GII. The most prevalent genotype was GI.4, followed by GII.4 and GII.21. Several variants of the pandemic GII.4 strain were detected in the environment, corroborating their circulation among the population.     

Occurrence,abundance and distribution of benthic macroinvertebrates in the Nyando River catchment,Kenya

A baseline study was conducted of the occurrence of macroinvertebrates at 26 sites in the Nyando River catchment in 2005–2006. A total of 13 orders and 16 families of Arthropoda, Mollusca, Platyhelminthes and Annelida were collected, with the order Ephemeroptera being most abundant in the up- and mid-stream reaches, followed by Hemiptera and Plecoptera respectively. The downstream sections of the river were dominated by Hirudinea and tubificids, as the water quality deteriorated mainly due to local land use, raw sewage effluent discharge and annual floods. Insects and annelids were the main invertebrates found and the extent of pollution increased from mid-section (Site 15) downwards as the river flowed into the Winam Gulf. Stringent management measures are required to safeguard the environment and ecosystems of Lake Victoria.     

Genetic Diversity of Escherichia coli Isolated from Urban Rivers and Beach Water

Repetitive element anchored PCR was used to evaluate the genetic profiles of Escherichia coli isolated from surface water contaminated with urban stormwater, sanitary sewage, and gull feces to determine if strains found in environmental samples reflect the strain composition of E. coli obtained from host sources. Overall, there was less diversity in isolates collected from river and beach sites than with isolates obtained from human and nonhuman sources. Unique strain types comprised 28.8, 29.2, and 15.0% of the isolate data sets recovered from stormwater, river water, and beach water, respectively. In contrast, 50.4% of gull isolates and 41.2% of sewage isolates were unique strain types. River water, which is expected to contain E. coli strains from many diffuse sources of nonpoint source pollution, contained strains most closely associated with other river water isolates that were collected at different sites or on different days. However, river sites impacted by sewage discharge had approximately 20% more strains similar to sewage isolates than did sites impacted by stormwater alone. Beach sites with known gull fecal contamination contained E. coli most similar to other beach isolates rather than gull isolates collected at these same sites, indicating underrepresentation of possible gull strains. These results suggest large numbers of strains are needed to represent contributing host sources within a geographical location. Additionally, environmental survival may influence the composition of strains that can be recovered from contaminated waters. Understanding the ecology of indicator bacteria is important when interpreting fecal pollution assessments and developing source detection methodology.     

Genetic diversity of Escherichia coli isolated from urban rivers and beach water

Repetitive element anchored PCR was used to evaluate the genetic profiles of Escherichia coli isolated from surface water contaminated with urban stormwater, sanitary sewage, and gull feces to determine if strains found in environmental samples reflect the strain composition of E. coli obtained from host sources. Overall, there was less diversity in isolates collected from river and beach sites than with isolates obtained from human and nonhuman sources. Unique strain types comprised 28.8, 29.2, and 15.0% of the isolate data sets recovered from stormwater, river water, and beach water, respectively. In contrast, 50.4% of gull isolates and 41.2% of sewage isolates were unique strain types. River water, which is expected to contain E. coli strains from many diffuse sources of nonpoint source pollution, contained strains most closely associated with other river water isolates that were collected at different sites or on different days. However, river sites impacted by sewage discharge had approximately 20% more strains similar to sewage isolates than did sites impacted by stormwater alone. Beach sites with known gull fecal contamination contained E. coli most similar to other beach isolates rather than gull isolates collected at these same sites, indicating underrepresentation of possible gull strains. These results suggest large numbers of strains are needed to represent contributing host sources within a geographical location. Additionally, environmental survival may influence the composition of strains that can be recovered from contaminated waters. Understanding the ecology of indicator bacteria is important when interpreting fecal pollution assessments and developing source detection methodology.     

Higher Isolation of NDM-1 Producing Acinetobacter baumannii from the Sewage of the Hospitals in Beijing

Multidrug resistant microbes present in the environment are a potential public health risk. In this study, we investigate the presence of New Delhi metallo-β-lactamase 1 (NDM-1) producing bacteria in the 99 water samples in Beijing City, including river water, treated drinking water, raw water samples from the pools and sewage from 4 comprehensive hospitals. For the bla _NDM-1 positive isolate, antimicrobial susceptibility testing was further analyzed, and Pulsed Field Gel Electrophoresis (PFGE) was performed to determine the genetic relationship among the NDM-1 producing isolates from sewage and human, as well as the clinical strains without NDM-1. The results indicate that there was a higher isolation of NDM-1 producing Acinetobacter baumannii from the sewage of the hospitals, while no NDM-1 producing isolates were recovered from samples obtained from the river, drinking, or fishpond water. Surprisingly, these isolates were markedly different from the clinical isolates in drug resistance and pulsed field gel electrophoresis profiles, suggesting different evolutionary relationships. Our results showed that the hospital sewage may be one of the diffusion reservoirs of NDM-1 producing bacteria.     

Prevalence of Giardia cysts and Cryptosporidium oocysts and characterization of Giardia spp. isolated from drinking water in Canada.

This study was carried out to estimate the prevalence and potential for human infectivity of Giardia cysts in Canadian drinking water supplies. The presence of Cryptosporidium oocysts was also noted, but isolates were not collected for further study. A total of 1,760 raw water samples, treated water samples, and raw sewage samples were collected from 72 municipalities across Canada for analysis, 58 of which treat their water by chlorination alone. Giardia cysts were found in 73% of raw sewage samples, 21% of raw water samples, and 18.2% of treated water samples. There was a trend to higher concentration and more frequent incidence of Giardia cysts in the spring and fall, but positive samples were found in all seasons. Cryptosporidium oocysts were found in 6.1% of raw sewage samples, 4.5% of raw water samples, and 3.5% of treated water samples. Giardia cyst viability was assessed by infecting Mongolian gerbils (Meriones unguiculatus) and by use of a modified propidium iodide dye exclusion test, and the results were not always in agreement. No Cryptosporidium isolates were recovered from gerbils, but 8 of 276 (3%) water samples and 19 of 113 (17%) sewage samples resulted in positive Giardia infections. Most of the water samples contained a low number of cysts, and 12 Giardia isolates were successfully recovered from gerbils and cultured. Biotyping of these isolates by isoenzyme analysis and karyotyping by pulsed-field gel electrophoresis separated the isolates into the same three discrete groups. Karyotyping revealed four or five chromosomal bands ranging in size from 0.9 to 2 Mb, and four of the isolates had the same banding pattern as that of the WB strain. Analysis of the nucleotide sequences of the 16S DNA coding for rRNA divided the isolates into two distinct groups corresponding to the Polish and Belgian designations found by other investigators. The occurrence of these biotypes and karyotypes appeared to be random and was not related to geographic or other factors (e.g., different types were found in both drinking water and sewage from the same community). Biotyping and karyotyping showed that isolates from this study were genetically and biochemically similar to those found elsewhere, including well-described human source strains such as WB. We conclude that potentially human-infective Giardia cysts are commonly found in raw surface waters and sewage in Canada, although cyst viability is frequently low. Cryptosporidium oocysts are less common in Canada. An action level of three to five Giardia cysts per 100 liters in treated drinking water is proposed on the basis of the monitoring data from outbreak situations. This action level is lower than that proposed by Haas and Rose (C. N. Haas and J. B. Rose, J. Am. Water Works Assoc. 87(9):81-84, 1995) for Cryptosporidium spp. (10 to 30 oocysts per 100 liters).     

Development of toxicity tolerant water hyacinth (Eichhornea crassipes) for effective treatment of raw sewage

Pioneering research efforts in the handling of municipal sewage in developing countries have involved the use of water hyacinth (Eichhornea crassipes) to purify sewage for possible re-use of the effluent water for domestic purposes. The ability of water hyacinth to remove pollution from raw sewage has been found to be impaired by sewage toxicity. Trials were therefore carried out to adapt water hyacinth to toxicity and thereby increase its ability to remove pollutants from raw sewage. The plants were adapted using an active bio-degrader consisting of Pseudomonas aeruginosa, Escherichia coli, Klebsiella ozaenae, Klebsiella edwardsiella and Baccillus subtilis. The adaptation progressed through 20, 40, 60 and 80% sewage dilution until plants capable of growth in 100% raw sewage were obtained. Plants were observed for morphological growth and at four weeks, samples were collected for tissue analysis. The plants progressively absorbed nutrients from sewage up to the fourth week, when signs of toxicity were obsereved through wilting, loss of turgidity and reduction in leaf number. However, plants that survived through a series of adaptations under various sewage dilutions exhibited luxuriant growth on raw sewage. In synergy with the active bio-degrader, the efficiency of the adapted water hyacinth to remove pollutants (nutrients) from raw sewage was enhanced by 93%.     

Isolation and characterization of bacteriophages from fermenting sauerkraut

This paper presents the first report of bacteriophage isolated from commercial vegetable fermentations. Nine phages were isolated from two 90-ton commercial sauerkraut fermentations. These phages were active against fermentation isolates and selected Leuconostoc mesenteroides and Lactobacillus plantarum strains, including a starter culture. Phages were characterized as members of the Siphoviridae and Myoviridae families. All Leuconostoc phages reported previously, primarily of dairy origin, belonged to the Siphoviridae family.     

Bacteriophages from the forestomachs of Australian marsupials.

Bacteriophages were observed in forestomach contents from three species of Australian macropodoid marsupials possessing a foregut fermentative digestion: the eastern grey kangaroo (Macropus giganteus), the eastern wallaroo (Macropus robustus robustus), and the rufous bettong (Aepyprymnus rufescens). Forty-six morphologically distinct phage types, representing the families Myoviridae, Siphoviridae, and Podoviridae, were identified. The range of forms varied between host species. The greatest diversity of phage types was found in forestomach contents of the wallaroo, and few phage types were recorded from the rufous bettongs. It is concluded that macropodoid marsupials, in common with their eutherian counterparts, possess diverse populations of bacteriophages in their fermentative forestomachs.     

Bacteriophages from the forestomachs of Australian marsupials.

Bacteriophages were observed in forestomach contents from three species of Australian macropodoid marsupials possessing a foregut fermentative digestion: the eastern grey kangaroo (Macropus giganteus), the eastern wallaroo (Macropus robustus robustus), and the rufous bettong (Aepyprymnus rufescens). Forty-six morphologically distinct phage types, representing the families Myoviridae, Siphoviridae, and Podoviridae, were identified. The range of forms varied between host species. The greatest diversity of phage types was found in forestomach contents of the wallaroo, and few phage types were recorded from the rufous bettongs. It is concluded that macropodoid marsupials, in common with their eutherian counterparts, possess diverse populations of bacteriophages in their fermentative forestomachs.     

Morphology of Brochothrix thermosphacta phages

Twenty-one Brochothrix thermosphacta phages were examined by electron microscopy. They had isometric heads and contractile or long and noncontractile tails, and were grouped into three species belonging to the Myoviridae (species A19) or Siphoviridae (species NF5 and BL3) families of tailed phages. Species A19 has highly characteristic morphological features and resembles well-known phages of Bacillus, Lactobacillus, Staphylococcus and Streptococcus, indicating phylogenetic relationships between these phages as well as their hosts.     

Genogroup distribution of F-specific coliphages in wastewater and river water in the Kofu basin in Japan

Aims: To determine the genogroup distribution of F‐specific coliphages in aquatic environments using the plaque isolation procedure combined with genogroup‐specific real‐time PCR. Methods and Results: Thirty water samples were collected from a wastewater treatment plant and a river in the Kofu basin in Japan on fine weather days. F‐specific coliphages were detected in all tested samples, 187 (82%) of 227 phage plaques isolated were classified into one of the 4 F‐specific RNA (F‐RNA) coliphage genogroups and 24 (11%) plaques were F‐specific DNA coliphages. Human genogroups II and III F‐RNA coliphages were more abundant in raw sewage than animal genogroups I and IV, excluding one sample that was suspected to be heavily contaminated with sporadic heavy animal faeces. The secondary‐treated sewage samples were highly contaminated with genogroup I F‐RNA coliphages, probably because of different behaviours among the coliphage genogroups during wastewater treatment. The river water samples were expected to be mainly contaminated with human faeces, independent of rainfall effects. Conclusions: A wide range of F‐specific coliphage genogroups were successfully identified in wastewater and river water samples. Significance and Impact of the Study: Our results clearly show the usefulness of the genogroup‐specific real‐time PCR for determining the genogroups of F‐specific coliphages present in aquatic environments.     

沙颍河流域人为输入对水体水化学组成的影响

人类活动输入影响河流水体化学组成,增加经河流体系向海洋输出物质的通量,影响全球物质循环过程.有效识别人为输入的影响途径和范围对于量化人类活动对全球物质循环的影响具有重要作用.沙颍河是淮河上游最大支流,流域水体受人为输入影响严重,通过研究沙颍河流域强人为输入对河水水化学组成的影响过程,有利于弄清楚强烈人为活动干扰下河流输...     

Salmonellae and pollution indicator bacteria in municipal and food processing effluents and the Cornwallis River

A study was conducted to determine the incidence of fecal coliforms, fecal streptococci, Aeromonas hydrophilia, and Salmonella spp. in the waste discharges of seven sewage treatment plants, four fruit and vegetable canneries, a meat packing plant, a poultry processing plant, and a potato processing plant located along the Cornwallis River in Nova Scotia, Canada. Surface water samples were also collected from 13 locations in the river to assess the impact of these waste discharges on the receiving water quality. The results showed that the final effluents from most of the sewage treatment and processing plants were of very poor bacteriological quality, with the number of indicator bacteria comparable with those found in raw sewage. Salmonellae were isolated from the effluents of the meat and poultry plants and five of the seven sewage treatment plants surveyed. No salmonellae were detected in the effluents of the fruit and vegetable canneries. The impact of the discharge of untreated municipal and food processing wastes on the Cornwallis River water quality was evidenced by the recovery from river water of five Salmonella serotypes, and the high fecal coliform counts which exceeded recommended limit for bathing and shellfish harvesting.     

Detection of Legionella species in sewage and ocean water by polymerase chain reaction, direct fluorescent-antibody, and plate culture methods.

Legionella spp. are ubiquitous in most environmental water sources; however, sewage treatment plants have not been examined as potential environmental reservoirs for these bacteria. This study used polymerase chain reaction, direct fluorescent-antibody staining, and culture methods to examine raw and treated sewage, ocean-receiving waters, and nearshore coastal environments for the presence of Legionella pneumophila and other Legionella spp. The study concluded that Legionella spp. are present in all phases of sewage treatment and that population numbers do not significantly decline through the treatment process. Ocean-receiving waters located 5 miles offshore, where the treated sewage is discharged, were found to contain Legionella spp., but ocean water between the discharge site and coastal bathing beaches was negative. This suggests that the Legionella spp. from the ocean discharge site were not reaching the nearshore beach waters. A flood control channel and river that entered the ocean were found to contain Legionella spp., and a nearby beach swimming area was also found to be positive, suggesting that land runoff from the flood control channel and river were the source of the Legionella spp. in the beach water samples that tested positive.