Use of gene probes for the detection of quiescent enteric bacteria in marine and fresh waters

1995 ◽  
Vol 31 (5-6) ◽  
pp. 291-298
Author(s):  
Sally A. Anderson ◽  
Gillian D. Lewis ◽  
Michael N. Pearson
Keyword(s):  
Membrane Filtration ◽  
Enteric Bacteria ◽  
Probe Method ◽  
Detection Methods ◽  
23S Rrna ◽  
Specific Gene ◽  
Gene Probe ◽  
Selective Media ◽  
Selective Enrichment ◽  
E Coli

Specific gene probe detection methods that utilise a non-selective culturing step were tested for the ability to recognise the presence of quiescent enteric bacteria (Escherichia coli and Enterococcus faecalis ) within illuminated freshwater and seawater microcosms. An E. coli specific uidA gene probe and a 23S rRNA oligonucleotide probe for Enterococci were compared with recoveries using membrane filtration and incubation on selective media (mTEC and mE respectively). From these microcosm experiments a greater initial detection (from 4 hours to 1 day) of E. coli and Ent. faecalis using gene probe methods was observed. Additionally, a comparison of E. coli direct viable counts (DVC) in sunlight exposed microcosms with recoveries by selective media and gene probe methods revealed a large number of viable non-culturable cells. This suggests that enumeration of E. coli by a gene probe method is limited by the replication of the bacteria during the initial non-selective enrichment step. The detection of stressed Ent. faecalis by the oligonucleotide gene probe method was significantly greater than recovery on selective mE agar, indicating an Enterococci non-growth phase.

scholarly journals A Syringe-Based Biosensor to Rapidly Detect Low Levels of Escherichia Coli (ECOR13) in Drinking Water Using Engineered Bacteriophages

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1953 ◽  
Author(s):  
Troy C. Hinkley ◽  
Spencer Garing ◽  
Paras Jain ◽  
John Williford ◽  
Anne-Laure M. Le Ny ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Membrane Filtration ◽  
Genetically Engineered ◽  
World Health ◽  
Selective Enrichment ◽  
E Coli ◽  
Detection Assay ◽  
Colony Forming Units ◽  
Health Organization

A sanitized drinking water supply is an unconditional requirement for public health and the overall prosperity of humanity. Potential microbial and chemical contaminants of drinking water have been identified by a joint effort between the World Health Organization (WHO) and the United Nations Children’s Fund (UNICEF), who together establish guidelines that define, in part, that the presence of Escherichia coli (E. coli) in drinking water is an indication of inadequate sanitation and a significant health risk. As E. coli is a nearly ubiquitous resident of mammalian gastrointestinal tracts, no detectable counts in 100 mL of drinking water is the standard used worldwide as an indicator of sanitation. The currently accepted EPA method relies on filtration, followed by growth on selective media, and requires 24–48 h from sample to results. In response, we developed a rapid bacteriophage-based detection assay with detection limit capabilities comparable to traditional methods in less than a quarter of the time. We coupled membrane filtration with selective enrichment using genetically engineered bacteriophages to identify less than 20 colony forming units (CFU) E. coli in 100 mL drinking water within 5 h. The combination of membrane filtration with phage infection produced a novel assay that demonstrated a rapid, selective, and sensitive detection of an indicator organism in large volumes of drinking water as recommended by the leading world regulatory authorities.

scholarly journals Assessment of faecal contamination in selected concrete and earthen ponds stocked with Clarias gariepinus

2022 ◽  
Author(s):  
ADEWALE OLUWASOGO OLALEMI ◽  
OLUWABUSAYOMI MARY OLUYEMI ◽  
MICHAEL TOSIN BAYODE
Keyword(s):  
Water Samples ◽  
Membrane Filtration ◽  
Clarias Gariepinus ◽  
Enteric Bacteria ◽  
Physicochemical Characteristics ◽  
Faecal Coliforms ◽  
E Coli ◽  
Faecal Pollution ◽  
Earthen Ponds ◽  
Concrete Pond

Abstract Background This study was carried out to monitor the levels of faecal pollution markers in catfish (Clarias gariepinus) and their growing waters in selected earthen and concrete ponds. Water and catfish samples were collected weekly in the months of February, March, April, May, June and July, 2019. The concentrations of enteric bacteria in the water and catfish samples were determined using membrane filtration and pour plate methods, respectively. The rate of bioaccumulation of faecal indicator bacteria was obtained by dividing the log concentration of each organism in catfish by the corresponding log concentration in the growing waters. Result The concentration of faecal coliforms in catfish samples from concrete and earthen ponds ranged from 1.41 to 2.28 log10 CFU/100 ml and 1.3 to 2.47 log10 CFU/100 ml respectively and in growing waters from the concrete and earthen ponds; 1.43 to 2.41 log10 CFU/100 ml and 1.50 to 2.80 log10 CFU/100 ml respectively. Faecal coliforms exhibited positive relationships with alkalinity in water samples from the earthen (r = 0.61) and concrete ponds (r = 0.62). Salmonella and faecal coliforms had the highest and least bioaccumulation in catfish raised in earthen pond, respectively, whereas Salmonella and enterococci had the highest and least bioaccumulation in catfish raised in concrete pond, respectively. Faecal coliforms and E. coli had the highest and least counts in water samples from the earthen pond during the dry and wet months, Salmonella and E. coli had the highest and least counts in water samples from the concrete pond during the dry and wet months. Conclusion There were high levels of bacterial faecal pollution markers in water and C. gariepinus from the earthen and concrete ponds. Physicochemical characteristics of the water and seasonality played major roles in the rate of bioaccumulation of the faecal pollution markers in C. gariepinus raised in the earthen and concrete ponds.

Comparison of total and faecal coliforms as faecal indicator in eutrophicated surface water

2006 ◽  
Vol 54 (3) ◽  
pp. 185-190 ◽  
Author(s):  
J.E. Park ◽  
T.S. Ahn ◽  
H.J. Lee ◽  
Y.O. Lee
Keyword(s):  
Surface Water ◽  
Aeromonas Hydrophila ◽  
Membrane Filtration ◽  
Enteric Bacteria ◽  
Pollution Monitoring ◽  
Faecal Coliforms ◽  
Temperate Region ◽  
Filtration Method ◽  
E Coli ◽  
Faecal Pollution

The aim of this study was to evaluate the use of total coliforms (TC) and faecal coliforms (FC) using a membrane filtration method for precise monitoring of faecal pollution in Korean surface water. The samples were collected in Korea from both main rivers and their tributaries. Presumptive TC · FC were enumerated. The ratios of presumptive FC to TC were not constant, but varied widely, and TC were difficult to enumerate because of overgrowth by background colonies. For FC this was not the case. Seven hundred and three purified strains of presumptive TC · FC and their background colonies were biotyped using API 20E. Among 272 presumptive TC, non-faecal related species, Aeromonas hydrophila dominated (34.6%) and E. coli accounted for only 5.1%. In contrast, E. coli made up 89% of the 209 presumptive FC. Furthermore, of 164 background colonies on Endo Agar LES, 54.9% was A. hydrophila, while background colonies on m-FC Agar were few (58 strains), and despite their atypical colony appearance, most of them were biotyped as enteric bacteria. These results reveal that the detection of FC rather than TC using m-FC Agar is more appropriate for faecal pollution monitoring in eutrophicated surface water located in a temperate region.

Existence and Decontamination of HVC, Infectious Enteric Bacteria and Parasites in Sewaged Soils

2014 ◽  
Vol 3 (1) ◽  
pp. 150-158 ◽  
Author(s):  
Mohey A. Hassanain ◽  
Nawal A. Hassanain ◽  
Esam A. Hobballa ◽  
Fatma H. Abd- El Zaher ◽  
Mohamed Saber M. Saber
Keyword(s):  
Soil Sample ◽  
Potassium Permanganate ◽  
Enteric Bacteria ◽  
Sewage Effluent ◽  
Calcium Hypochlorite ◽  
Sand Soil ◽  
E Coli ◽  
Surface Sample ◽  
Loamy Sand Soil ◽  
Sewage Farm

A surface sample representing a high contaminated loamy sand soil irrigated with sewage effluent since 30 years and was cultivated with artichoke was collected from Abu-Rawash sewage farm. The existence of HVC, enteric infectious bacteria and parasites in sewaged soil found to be negative for the forward and positive for the latter's. Out of the 30 samples separated from the sewaged soil sample, only 3 samples contained parasitic fauna of developed and undeveloped Ascaris (10%) and five samples contained Entamoeba coli. Results showed that the number of Ascaris eggs/gm soil was 0.017 and the number of E. coli/gm was 0.26. Decontamination of soil parasites was effective using either calcium hypochlorite or potassium permanganate. Salmonella, Vibrio and Campelobacter were detected in the high contaminated sewaged soil and survived for 120 days in the sewaged soil under all control and bioremediated treatments irrigated with either sewage effluent or water.

Hygienic risk assessment by monitoring pathogens in municipal sewage

2002 ◽  
Vol 2 (3) ◽  
pp. 23-28 ◽  
Author(s):  
C.-H. von Bonsdorff ◽  
L. Maunula ◽  
R.M. Niemi ◽  
R. Rimhanen-Finne ◽  
M.-L. Hänninen ◽  
...  
Keyword(s):  
Enteric Viruses ◽  
Detection Methods ◽  
Municipal Sewage ◽  
Small Community ◽  
E Coli ◽  
Cryptosporidium Oocysts ◽  
High Concentrations ◽  
One Year ◽  
Enteric Protozoa ◽  
Day Care Centre

The purpose of this study was to monitor the levels of human enteric viruses and enteric protozoa and to relate their presence to the microbes used as hygienic quality indicators in domestic sewage from a small community in Finland during a period of one year. Genome-based sensitive detection methods for the pathogens selected (astro- and Norwalk-like viruses, Giardia and Cryptosporidium) have become available only recently and thus no earlier data was available. The effluent sewage is delivered into a river that serves as raw water for a larger town and the pathogens therefore constitute a health risk. The results showed that all the monitored pathogens could be detected, and that enteric viruses were present at considerable concentrations in sewage. High concentrations of astrovirus in raw sewage were observed during a diarrhea epidemic in the local day-care centre. The presence of viruses did not correlate with the monitored bacterial indicators of faecal contamination (coliforms, E. coli and enterococci) or with bacteriophages (somatic coliphages, F-specific RNA phages and B. fragilis phages). Giardia cysts and Cryptosporidium oocysts were detected from one sample (1/10) each.

Viruses and Water: Problems, Detection, and Control

1993 ◽  
Vol 27 (7-8) ◽  
pp. 127-133 ◽  
Author(s):  
H. Dizer ◽  
J. Dürkop ◽  
A. Grohmann ◽  
H. Kopecka ◽  
J. M. López-Pila
Keyword(s):  
Drinking Water ◽  
Surface Waters ◽  
Membrane Filtration ◽  
Wastewater Treatment Plants ◽  
Health Hazard ◽  
Primary Source ◽  
Detection Methods ◽  
Secondary Effluent ◽  
Naturally Occurring ◽  
Water Problems

Secondary effluent of wastewater treatment plants contains a high number of viruses and other pathogens, which pose a health risk to the population, (especially when receiv ng waters are used for bathing and swimming, or for growing shellfish. In areas with a high density of population, where drinking water supply is dependent on surface waters and contaminated rivers are the primary source of drinking water, failure of the filtration or of the disinfection step, or of any other “barriers” supposed to warrant safe potable water, will increase the risk of health hazard for the consumer. We have compared the efficiency of viral elimination in secondary effluent by flocculation, uv rradiation and membrane filtration taking naturally occurring, or additionally seeded f2 phages, as indicator for viruses. Flocculation decreased the number of phages present in secondary effluent by more than two logs. If combined with uv irradiation, the elimination reached five additional logs. Membrane filtration eliminated essentially all naturally occurring phages. Improvement of the quality of surface waters calls for a refinement of detection methods for viruses. We have found that the polymerase chain reaction (PCR) might be used for detecting viruses in surface waters.

An Improved Membrane Filtration Method for Enumeration of Faecal Coliforms and E. Coli by a Fluorogenic β-Glucuronidase Assay

1993 ◽  
Vol 27 (3-4) ◽  
pp. 267-270 ◽  
Author(s):  
M. T. Augoustinos ◽  
N. A. Grabow ◽  
B. Genthe ◽  
R. Kfir
Keyword(s):  
Escherichia Coli ◽  
Water Samples ◽  
Membrane Filtration ◽  
Faecal Coliforms ◽  
Environmental Waters ◽  
Filtration Method ◽  
E Coli ◽  
Wide Range ◽  
Pure Cultures ◽  
Glucuronidase Assay

A fluorogenic β-glucuronidase assay comprising membrane filtration followed by selective enumeration on m-FC agar at 44.5°C and further confirmation using tlie 4-metliylumbelliferyl-β-D-glucuronide (MUG) containing medium was evaluated for the detection of Escherichia coli in water. A total of 200 typical blue and non-typical blue colonies were isolated from sea and fresh water samples using initial selective enumeration on m-FC agar. Pure cultures of the selected colonies were further tested using the MUG assay and identified using the API 20E method. Of the colonies tested which were shown to be positive using the MUG assay 99.4% were Escherichia coli. The results of this study indicate the combination of the m-FC method followed by the MUG assay to be highly efficient for the selection and confirmation of E. coli from a wide range of environmental waters.

Microbiological performance and salmonella dynamics in a wastewater depuration pond system of southeastern spain

1995 ◽  
Vol 31 (12) ◽  
pp. 239-248 ◽  
Author(s):  
Ana Emparanza-Knörr ◽  
Francisco Torrella
Keyword(s):  
Fecal Coliform ◽  
No Reduction ◽  
Agar Medium ◽  
Microbiological Quality ◽  
Total Coliform ◽  
Fecal Coliforms ◽  
Selective Media ◽  
E Coli ◽  
The Village ◽  
Final Effluent

The Salmonella presence and the microbiological quality indicators, total and fecal coliforms and coliphages of E. coli C, have been studied in a overloaded wastewater lagoon system treating urban wastewatrers of the village of Guardamar del Segura (Alicante, Spain). Classical microbiological technology to detect salmonellae was used, including pre-enrichment, enrichment, selective media plating and biochemical and serological confirmation. Water was physicochemically characterized according to COD, SS, temperature, pH and dissolved oxygen. The selective migration step through Rappaport-Vassiliadis semisolid agar medium was essential for the consistent detection of Salmonella in the different lagoon effluents. Total and fecal coliform levels of up to 105-106 MPN/100 ml were detected in the final effluent. High coliphage concentrations of 103-104 pfu/ml were also found in the effluent waters. Salmonella was always detected in 100 ml samples and eventually reached an order of value of 103 MPN/100 ml. Total coliform reduction was higher in the anaerobic ponds whereas fecal coliforms were more efficiently eliminated in the facultative (mostly “anoxic”) lagoons. Coliphage reduction was higher in the facultative lagoons when compared to the anaerobic ponds. On many occasions, no reduction or eventual increment of the concentration of salmonellae was detected in the effluents from the anaerobic ponds compared to concentrations of the patohogen in the influent raw wasterwaters. The possibility exists for a capacity of Salmonella to multiply in the anoxic phase of the wastewater treatment, but the presence of microorganisms in raw sewage waters which could maskSalmonella detection with the enrichment methodology employed cannot be ruled out.

scholarly journals Comparison of the ColiPlate™ Kit with Two Common E. coli Enumeration Methods for Water

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1804
Author(s):  
Cassi J. Gibson ◽  
Abraham K. Maritim ◽  
Jason W. Marion
Keyword(s):  
High Risk ◽  
Natural Water ◽  
Membrane Filtration ◽  
Fecal Contamination ◽  
Reference Method ◽  
World Health ◽  
Risk Levels ◽  
E Coli ◽  
Field Samples ◽  
Very High

Quantitatively assessing fecal indicator bacteria in drinking water from limited resource settings (e.g., disasters, remote areas) can inform public health strategies for reducing waterborne illnesses. This study aimed to compare two common approaches for quantifying Escherichia coli (E. coli) density in natural water versus the ColiPlate™ kit approach. For comparing methods, 41 field samples from natural water sources in Kentucky (USA) were collected. E. coli densities were then determined by (1) membrane filtration in conjunction with modified membrane-thermotolerant E. coli (mTEC) agar, (2) Idexx Quanti-Tray® 2000 with the Colilert® substrate, and (3) the Bluewater Biosciences ColiPlate kit. Significant correlations were observed between E. coli density data for all three methods (p < 0.001). Paired t-test results showed no difference in E. coli densities determined by all the methods (p > 0.05). Upon assigning modified mTEC as the reference method for determining the World Health Organization-assigned “very high-risk” levels of fecal contamination (> 100 E. coli CFU/100 mL), both ColiPlate and Colilert exhibited excellent discrimination for screening very high-risk levels according to the area under the receiver operating characteristic curve (~89%). These data suggest ColiPlate continues to be an effective monitoring tool for quantifying E. coli density and characterizing fecal contamination risks from water.

scholarly journals Global versus Local Regulatory Roles for Lrp-Related Proteins: Haemophilus influenzae as a Case Study

2001 ◽  
Vol 183 (13) ◽  
pp. 4004-4011 ◽  
Author(s):  
Devorah Friedberg ◽  
Michael Midkiff ◽  
Joseph M. Calvo
Keyword(s):  
Amino Acid ◽  
Haemophilus Influenzae ◽  
Regulatory Protein ◽  
Enteric Bacteria ◽  
Regulatory Role ◽  
Regulatory Function ◽  
Ecological Niches ◽  
E Coli ◽  
Sequence Identity ◽  
Related Proteins

ABSTRACT Lrp (leucine-responsive regulatory protein) plays a global regulatory role in Escherichia coli, affecting expression of dozens of operons. Numerous lrp-related genes have been identified in different bacteria and archaea, includingasnC, an E. coli gene that was the first reported member of this family. Pairwise comparisons of amino acid sequences of the corresponding proteins shows an average sequence identity of only 29% for the vast majority of comparisons. By contrast, Lrp-related proteins from enteric bacteria show more than 97% amino acid identity. Is the global regulatory role associated withE. coli Lrp limited to enteric bacteria? To probe this question we investigated LrfB, an Lrp-related protein fromHaemophilus influenzae that shares 75% sequence identity with E. coli Lrp (highest sequence identity among 42 sequences compared). A strain of H. influenzae having anlrfB null allele grew at the wild-type growth rate but with a filamentous morphology. A comparison of two-dimensional (2D) electrophoretic patterns of proteins from parent and mutant strains showed only two differences (comparable studies withlrp + and lrp E. coli strains by others showed 20 differences). The abundance of LrfB in H. influenzae, estimated by Western blotting experiments, was about 130 dimers per cell (compared to 3,000 dimers per E. colicell). LrfB expressed in E. coli replaced Lrp as a repressor of the lrp gene but acted only to a limited extent as an activator of the ilvIH operon. Thus, although LrfB resembles Lrp sufficiently to perform some of its functions, its low abundance is consonant with a more local role in regulating but a few genes, a view consistent with the results of the 2D electrophoretic analysis. We speculate that an Lrp having a global regulatory role evolved to help enteric bacteria adapt to their ecological niches and that it is unlikely that Lrp-related proteins in other organisms have a broad regulatory function.

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