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PubMed2006

Effects of UV intensity and water turbidity on microbial indicator inactivation.

The effects of UV intensity and turbidity on selected microbial indicator inactivation were investigated. Results showed that UV disinfection was effective in killing all the selected microbial indicators, the resistance order of the microorganisms was as follows: MS-2 coliphage > Bacillus subtilis > E. coli > Staphylococcus aureus and Candida albicans. UV intensity had influence on the inactivation of all the microorganisms, high UV disinfection efficency was obtained with higher UV intensity. Turbidity had impact on the bacteria inactivation rate, but there was no evidence that turbidity had any negative contribution to MS-2 coliphage. Under the same UV dosage, higher UV intensity could overcome the negative influence of turbidity on UV performance, enhanced microorganism inactivation effect in turbidity water.

Bacillus subtilis↗
PubMed2004

Sludge accumulation, characteristics, and pathogen inactivation in four primary waste stabilization ponds in central Mexico.

To support the development of safe and feasible sludge management strategies, the accumulation rates of sludge and its characteristics were studied in four primary wastewater stabilization ponds (WSPs) in central Mexico (three facultative and one anaerobic). The accumulation rates and distribution of sludge were determined by measuring the thickness of the sludge layer at 8-40 locations throughout each pond. The average, per capita sludge accumulation rates ranged from 0.021 to 0.036m(3)/person/yr. In the anaerobic pond the sludge distribution was uniform throughout the pond, whereas in the three facultative ponds most of the sludge accumulated directly in front of the inlet. To measure the horizontal and vertical variation in the sludge characteristics, sludge cores were collected from 3 to 7 locations in three of the ponds. Each core was divided into 4 sub-samples in which various physical, chemical, and microbiological parameters were measured. In addition, the inactivation of several pathogen indicator organisms was studied in a batch of sludge for 7 months. Based on the microbiological results, it is concluded that reasonable estimates of the inactivation of fecal coliform bacteria, fecal enterococci, F+ coliphage, somatic coliphage, and Ascaris eggs in WSP sludge in central Mexico can be made using first-order rate constants of 0.1, 0.1, 0.01, 0.001, and 0.001d(-1), respectively. From the observed changes in the concentrations of total solids and the volatile to fixed solids ratio, empirical equations were developed to describe anaerobic degradation and compression, which are the two most important processes affecting the volume of sludge after its deposition.

Animals↗
PubMed2005

Nowcast modeling of Escherichia coli concentrations at multiple urban beaches of southern Lake Michigan.

Predictive modeling for Escherichia coli concentrations at effluent-dominated beaches may be a favorable alternative to current, routinely criticized monitoring standards. The ability to model numerous beaches simultaneously and provide real-time data decreases cost and effort associated with beach monitoring. In 2004, five Lake Michigan beaches and the nearby Little Calumet River outfall were monitored for E. coli 7 days a week; on nine occasions, samples were analyzed for coliphage to indicate a sewage source. Ambient lake, river, and weather conditions were measured or obtained from independent monitoring sources. Positive tests for coliphage analysis indicated sewage was present in the river and on bathing beaches following heavy rainfall. Models were developed separately for days with prevailing onshore and offshore winds due to the strong influence of wind direction in determining the river's impact on the beaches. Using regression modeling, it was determined that during onshore winds, E. coli could be adequately predicted using wave height, lake chlorophyll and turbidity, and river turbidity (R2 = 0.635, N = 94); model performance decreased for offshore winds using wave height, wave period, and precipitation (R2 = 0.320, N = 124). Variation was better explained at individual beaches. Overall, the models only failed to predict E. coli levels above the EPA closure limit (235 CFU/100 ml) on five of eleven occasions, indicating that the model is a more reliable alternative to the monitoring approach employed at most recreational beaches.

Bathing Beaches↗
PubMed2002

Regrowth and survival of indicator microorganisms on the surfaces of household containers used for the storage of drinking water in rural communities of South Africa.

The present study covered two rural communities of South Africa: Ncera and Ntselamanzi villages. Raw water from Ncera river is used by the community of Ncera village for drinking, while the community of Ntselamanzi receives their drinking water from Alice purification system. Treated water is supplied to the community by a public standpipe system. In rural communities of South Africa, many households use polyethylene (PE) and galvanized steel (GS) containers for the storage of their drinking water. To investigate the regrowth and survival of indicator microorganisms on the surface of household containers during the storage of drinking water, PE and GS slides were suspended in the appropriate household containers for a period of 48 h. This period of 48 h was chosen as the study period because results from the questionnaire indicated that the largest percentage (62%) of households store their water for that length of time. The experiment was performed to test drinking water as it is collected and stored by rural communities. No disinfection of household containers or slides was done during the study period. Attached coliphages (F-RNA (FP) and somatic phage (SP), coliform bacteria (total coliform (TC), presumptive Escherichia coli (EC), Salmonella (Sal) and Clostridium perfringens (CP) were measured during the study period. With the exception of CP, attached indicator microorganisms consisted of TC, presumptive E. coli and Salmonella, somatic and F-RNA coliphages, although the yield (average count) for the last four groups (EC: < 1-3 cfu cm(-2), Sal: < 1-15 cfu cm(-2), FP: < 1-7 pfu cm(-2), SP: < 1-7pfu cm(-2)) was lower than that of TC (3-183 cfu cm(-2)). However, the lowest yield of indicator microorganisms was noted for presumptive E. coli. Whereas the occurrence and survival of TC was noted on the surface of household containers during the entire period of the experimental study, other indicator microorganisms occurred from time to time. The regrowth of indicator microorganisms occurred 48 h after the exposure of slides to both types of test waters. This length of time mostly resulted in the regrowth of TC (with an increase in bacterial counts) while the persistence of other indicator organism groups on the surface of the slides was apparent. A comparison between PE and GS containers showed that more TC (average count) regrew on PE than on GS containers (for river water, PE: from 36 to 55 cfu cm(-2), GS: from 25 to 26 cfu cm(-2); for standpipe water, PE: from 147 to 183 cfu cm(-2), GS from 3 to 4 cfu cm(-2)). This study revealed that both types of household containers supported the growth and survival of indicator microorganisms due to the bad quality of the intake water before storage. The storage of drinking water for 48 h mainly resulted in the regrowth of TC. Nevertheless, the persistence of other indicator microorganisms was observed on the surface of household containers.

Biofilms↗
PubMed1994

Bacteriophages presence in human faeces of healthy subjects and patients with gastrointestinal disturbances.

The variation of the content of enteric bacteria and their bacteriophages in faeces from the different types of diarrhoeal processes has been studied. A total of 122 samples of human faeces from both healthy individuals and patients with diarrhoeal diseases of functional or infectious origin were tested. Detection rates for all microbial parameters tested decreased in the faeces of individuals with functional gastrointestinal disturbances. On the contrary, no significant differences of the microbial detection frequency was observed in faeces containing pathogenic microorganisms compared to faeces of healthy subjects. Human faeces were a poor source of F-specific, Salmonella, and Bacteroides bacteriophages, whereas specific Escherichia coli phages were isolated in most samples tested. Coliphage concentrations in faeces of healthy individuals were not directly correlated with levels of faecal coliforms. On the basis of their high correlation, faecal streptococci and coliphages were the most adequate indicators of the intestinal ecosystem variations in subjects with diarrhoeal processes.

Bacteriophages↗
PubMed1999

Assessment of microbial parameters as indicators of viral contamination of aerosol from urban sewage treatment plants.

In order to evaluate possible indicators of viral aerosol contamination in sewage treatment plants, a year-long study was carried out on the relationships between the presence of cytopathogenic viruses and the counts of total bacteria, faecal streptococci and somatic coliphages in samples collected at various distances from the aerosol source (aeration tank). The activated sludge plant studied proved to be a significant source of microbe-bearing aerosol with high levels of viral contamination. When the virus was found in sewage, it was also found in the air, at least in the sites closest to the aeration tank. With regard to the possibility of using the chosen parameters as markers of viral contamination, the total bacteria and faecal streptococci counts were generally positively correlated with viral presence, while coliphage counts yielded no analogous relationship.

Aerosols↗
PubMed1999

Occurrence and levels of phages proposed as surrogate indicators of enteric viruses in different types of sludges.

A method based on the treatment of sludge with beef extract recovered, with similar efficiency, the three groups of bacteriophages studied from different kinds of sludges. The three groups of bacteriophages were found in high numbers in the different sludge types, the highest value being that of somatic coliphages in primary sludge of a biological treatment plant (1.1 x 10(5) pfu g-1) and the lowest being that of Bacteroides fragilis phages (110 pfu g-1) in de-watered, anaerobically, mesophilically-digested sludge. All phages studied accumulated in the sludges. In primary and activated sludges, all three types accumulated similarly but in lime-treated sludge and de-watered, anaerobically, mesophilically-digested sludge, the relative proportion of F-specific bacteriophages decreased significantly with respect to somatic coliphages and bacteriophages infecting B. fragilis. All phages survived successfully in stored sludge, depending on the temperature, and again, F-specific bacteriophages survived less successfully than the others.

Bacteriophages↗
PubMed2002

Pulsed high voltage electric discharge disinfection of microbially contaminated liquids.

AIMS: To examine the use of a novel multielectrode slipping surface discharge (SSD) treatment system, capable of pulsed plasma discharge directly in water, in killing micro-organisms. METHODS AND RESULTS: Potable water containing Escherichia coli and somatic coliphages was treated with pulsed electric discharges generated by the SSD. The SSD system was highly efficient in the microbial disinfection of water with a low energy utilization (eta approximately 10-4 kW h l-1). CONCLUSIONS: The SSD treatment was effective in the destruction of E. coli and its coliphages through the generation of u.v. radiation, ozone and free radicals. SIGNIFICANCE AND IMPACT OF THE STUDY: The non-thermal treatment method can be used for the eradication of micro-organisms in a range of contaminated liquids, including milk, negating the use of pasteurization. The method utilizes multipoint electric discharges capable of treating large volumes of liquid under static and flowing regimes.

Coliphages↗
PubMed1986

Engineering of the mRNA-interfering complementary RNA immune system against viral infection.

Creation of an artificial mRNA-interfering complementary RNA (micRNA) immune system, utilizing anti-sense RNAs to inhibit viral gene expression, has been shown to be an effective way to prevent viral infection. In the RNA coliphage SP, the gene for the maturation protein was found to be the best target for this type of immune system; mRNA-interfering complementary RNAs specific to the genes for coat protein and replicase were less effective in preventing infection. The greatest inhibitory effect was observed with a 240-base sequence encompassing the 24-base noncoding region of the maturation gene plus the 216-base coding sequence. Significantly, even a 19-base sequence covering only the Shine-Dalgarno sequence (ribosome-binding region) without the coding region exerted a strong inhibitory effect on phage proliferation. In contrast to the highly specific action against phage SP exhibited by the longer mRNA-interfering complementary RNA, the specificity with the shorter mRNA-interfering complementary RNA was broadened to phages Q beta and GA as well as SP, all of which are classified in the different groups of RNA coliphages. Therefore, this type of anti-viral reagent may be designed to have a particular breadth of specificity, thus increasing its value in various research and possibly clinical applications.

Base Sequence↗
PubMed1976

A method for biological testing of containment systems for viral agents.

A technique utilizing coliphage as the test material has been developed and employed to evaluate the effectiveness of a containment system for zonal centrifugation of hepatits viruses. An Andersen Viable Particle Sampler which had been loaded with plates containing a base layer of agar nutrient with an overlay of E. coli- agar suspension was used to sample the test air. The containment system, which includes a HEPA filter, was challenged with an aerosolized suspension of coliphage.

Air Microbiology↗
PubMed2006

Fecal contamination of agricultural soils before and after hurricane-associated flooding in North Carolina.

Hurricane Floyd and other storms in 1999 caused widespread and extensive flooding of eastern North Carolina and environmental contamination with fecal wastes from municipal wastewater and livestock operations. Because wastewater contains high levels of pathogenic micro-organisms, principal health risks to humans from flooding are consumption of crops grown in fecally contaminated soil and ingestion of contaminated water. Flood waters polluted with microbial and other contaminants also may be detrimental to the health of livestock and plant crops. In the present study, agricultural soils impacted by flood waters were analyzed for bacterial and viral indicators of fecal contamination. Total coliforms, fecal coliforms, Escherichia coli, spores of Clostridium perfringens, and both male specific (F+) and somatic coliphages were recovered from soil and assayed in liquid culture media. A number of samples were positive for the presence of fecal coliforms, E. coli, and coliphages, indicating the presence of human or animal feces. Most samples were positive for total coliforms, and almost all samples contained high levels of Cl. perfringens spores. The levels of Cl. perfringens spores were significantly (P < 0.001) higher in flooded soil (post-Hurricane Floyd) compared to pre-flood soil. Persistent fecal contamination of soil, as demonstrated by the high levels of Cl. perfringens spores, suggests the need for additional or alternative measures to protect crop-growing areas, including prospective microbiological monitoring and improved protection of watersheds from incidents capable of releasing fecal material.

Agriculture↗
PubMed2001

Removal of pathogenic and indicator microorganisms by a constructed wetland receiving untreated domestic wastewater.

Wetlands containing floating, emergent and submergent aquatic plants, and other water-tolerant species have been found to economically provide a mechanism of enhancing the quality of domestic wastewater. The use of constructed wetlands for the removal of indicator bacteria (total and fecal coliforms), coliphages, protozoan parasites (Giardia and Cryptosporidium) and enteric viruses was investigated. A pilot scale constructed wetland consisting of two cells, one planted with bulrush and the other unplanted bare sand, were used to compare their efficiency in removing pathogens from raw sewage. Overall more than 90 percent of all microorganisms studied were removed by either of the two systems with a 1 to 2 day retention time. Removal of all mentioned microorganisms was greater from the surface flow in the unplanted cell than in the planted cell, except for Giardia and Cryptosporidium, although the differences were not statistically significant. Enteric viruses, coliphages and indicator bacteria were found to penetrate 2 m below the surface, although concentrations were reduced by greater than 99 percent in both cells. Less virus penetration into the sand occurred in the planted wetland versus the unplanted wetland. Water temperature was found to be the most important factor in the removal of enteric bacteria and viruses, while turbidity reduction was related to Giardia removal. These results demonstrate that significant reductions of pathogenic microorganisms can occur in constructed wetlands receiving untreated domestic wastewater with only a 1-2 day retention time.

Animals↗
PubMed1975

Bacteriophages and endotoxin in licensed live-virus vaccines.

In confirmation of recent reports, coliphages were found in seven of 19 unselected samples of the currently licensed live-virus vaccines. Coliphages and pseudomonas phage were found in 11 and 14, respectively, of the 20 bovine sera commonly used in the cell culture phase of virus vaccine production. The same lots of vaccine and serum were examined by the limulus assay for endotoxin, another product of bacterial contamination. Eighteen of 20 sera had detectable endotoxin-like activity. Our preliminary results suggest that endotoxin activity may serve as a sensitive indicator of residual products of previous bacterial contamination, including bacteriophages.

Animals↗
PubMed1991

The putative single-stranded DNA-binding protein of the filamentous bacteriophage, Ifl. Amino acid sequence of the protein and structure of the gene.

The protein product corresponding to the gene located in the region of the coliphage Ifl genome shown to contain the code for the single-stranded DNA (ssDNA)-binding proteins of all filamentous phages so far studied has been isolated from infected bacterial cells and its amino acid sequence determined. The mature protein contains 95 amino acids (calculated molecular mass 10553 Da). Its sequence corresponds to that predicted from the DNA sequence but lacks the initiating methionine residue. Although there is little direct sequence homology between the phage Ifl protein and the ssDNA-binding proteins of the other filamentous phages that have been studied, computer-based comparisons of various physical and structural parameters showed that the phage Ifl protein contains a domain that is closely related to domains in the coliphage T4 gene 32 protein and the Pseudomonas phage Pfl ssDNA-binding protein and suggest that the Ifl protein does have a ssDNA-binding function although we were unable to show this directly.

Amino Acid Sequence↗
PubMed1986

Bacteriophages and indicator bacteria in human and animal faeces.

In an attempt to explain the presence of F-specific (RNA) bacteriophages in waste-water, faecal material from humans and a variety of animals was examined. The phages were detected in appreciable numbers only in faeces from pigs, broiler chickens, sheep and calves but not from dogs, cows, horses and humans. Parallel examinations for somatic coliphages, thermotolerant coliforms, faecal streptococci and spores of sulphite-reducing clostridia revealed the consistent presence of these organisms in all types of samples, albeit in variable numbers. The number of F-specific bacteriophages was related to the total number of somatic coliphages, but phage counts were unrelated to bacterial counts. F-specific RNA phages were grouped by serotyping and all animal isolates were found to belong to either group I (MS2 subtype) or IV (four different subtypes). Among the group IV isolates, most belonged to well-known subtypes SP (24 isolates) or FI (18 isolates) but five isolates were related to phage ID2 and one isolate was a new subtype. In contrast with animal isolates, 19 isolates from hospital wastewater belonged to serogroups II or III.

Animals↗
PubMed1990

F-specific RNA bacteriophages and sensitive host strains in faeces and wastewater of human and animal origin.

Faeces of humans, pigs, cattle and chickens were investigated for the presence of somatic coliphages, F-specific bacteriophages and Escherichia coli strains sensitive to infection by F-specific phages. Attention was given to the possible effect of age and use of antibiotics on the prevalence of the FRNA phages and sensitive E. coli strains. Somatic coliphages were often detected in high numbers in all types of faeces. In contrast, FRNA phages were rarely detected in faeces from humans and cattle but more often in faeces from pigs and adult chickens. Samples from young chickens (with or without antibiotics) were consistently positive for FRNA phages (up to 3 x 10(6) pfu/g). F-specific RNA phages were found in substantial numbers (greater than 10(3) pfu/ml) in a variety of wastewaters: domestic, hospital, slaughterhouses and occasionally in 'grey water'. Their origin in wastewater was not clear. Strains from faeces usually belonged to serogroups I and IV. These types were also found in wastewater, as were group II and III strains. Serogroup II phages were abundant in wastewater of human origin but rare in faeces. Escherichia coli strains sensitive to infection by F-specific phages were common in faeces (overall 290/1081: 27%). No strains with fully depressed F-pilus synthesis were detected among the sensitive strains. It is concluded that the occurrence of F-specific RNA bacteriophages in water points to sewage pollution rather than faecal pollution; the mechanism of replication of these organisms in wastewater is not understood.

Aging↗
PubMed2004

Inactivation of indicator micro-organisms from various sources of faecal contamination in seawater and freshwater.

AIM: The survival of indicator micro-organisms in aquatic systems is affected by both biotic and abiotic factors. Much of the past research on this topic has been conducted using laboratory-generated cultures of indicator bacteria. For this study, we used natural sources of faecal contamination as inoculants into environmental water samples, thereby representing the wide diversity of organisms likely to be found in faecal contamination. METHODS AND RESULTS: Rates of inactivation of water quality indicators, total coliforms (TC), Escherichia coli, enterococci (EC) and F+-specific coliphage were studied in three experiments using inoculants of sewage influent, sewage effluent and urban storm drain run-off. Effects of temperature, nutrients, total suspended solids, bacterial load and solar irradiation were studied in fresh and seawater matrices. Results demonstrated that temperature and solar irradiation had significant effects upon rates of inactivation (anova, P < 0.001). Inactivation rates were similar, regardless of the inoculant type. EC degraded the slowest in the dark with T90s of 115-121 and 144-177 h at 20 and 14 degrees C, respectively. When incubated in sunlight, EC was inactivated significantly more rapidly than either E. coli or F+-specific coliphage (P < 0.001). CONCLUSIONS: Inactivation of indicator bacteria is not dependent upon the original source of contamination. Inactivation rates of indicator bacteria were similar in fresh and seawater matrices. However, EC degraded more rapidly in sunlight than E. coli. SIGNIFICANCE AND IMPACT OF THE STUDY: This study suggests that the source of faecal contamination is not an important factor to inactivation rates of indicator bacteria. However, rates of inactivation of indicator bacteria are likely system specific.

Coliphages↗
PubMed2004

PCR detection of pathogenic viruses in southern California urban rivers.

AIMS: To investigate human viral contamination in urban rivers and its impact on coastal waters of southern California, USA. METHODS AND RESULTS: Three types of human viruses (adeno, entero and hepatitis A) were detected using nested- and RT-PCR from 11 rivers and creeks. Faecal indicator bacteria as well as somatic and F-specific coliphage were also tested. Approximately 50% of the sites were positive for human adenoviruses. However, there was no clear relationship between detection of human viruses and the concentration of indicator bacteria and coliphage. Both faecal indicator bacteria and human viral input at beaches near river mouths were associated with storm events. The first storm of the wet season seemed to have the greatest impact on the quality of coastal water than following storm events. CONCLUSIONS: This study provides the first direct evidence that human viruses are prevalent in southern California urban rivers. Urban run-off impacts coastal water quality most significantly during the storm season. SIGNIFICANCE AND IMPACT OF THE STUDY: To protect human health during water recreational activities, it is necessary to develop effective strategies to manage urban run-off during storm events.

Adenoviridae↗