scholarly journals New Molecular Quantitative PCR Assay for Detection of Host-Specific Bifidobacteriaceae Suitable for Microbial Source Tracking

2012 ◽  
Vol 78 (16) ◽  
pp. 5788-5795 ◽  
Author(s):  
Marta Gómez-Doñate ◽  
Elisenda Ballesté ◽  
Maite Muniesa ◽  
Anicet R. Blanch
Keyword(s):  
Host Specificity ◽  
Quantitative Pcr ◽  
Microbial Source Tracking ◽  
Source Tracking ◽  
Content Type ◽  
Practical Applications ◽  
Urban Sewage ◽  
Culture Independent ◽  
Low Prevalence ◽  
High Degree

ABSTRACTBifidobacteriumspp. belong to the commensal intestinal microbiota of warm-blooded animals. Some strains ofBifidobacteriumshow host specificity and have thus been proposed as host-specific targets to determine the origin of fecal pollution. Most strains have been used in microbial-source-tracking (MST) studies based on culture-dependent methods. Although some of these approaches have proved very useful, the low prevalence of culturableBifidobacteriumstrains in the environment means that molecular culture-independent procedures could provide practical applications for MST. Reported here is a set of common primers and fourBifidobacteriumsp. host-associated (human, cattle, pig, and poultry) probes for quantitative-PCR (qPCR) assessment of fecal source tracking. This set was tested using 25 water samples of diverse origin: urban sewage samples, wastewater from four abattoirs (porcine, bovine, and poultry), and water from a river with a low pollution load. The selected sequences showed a high degree of host specificity. There were no cross-reactions between the qPCR assays specific for each origin and samples from different fecal origins. On the basis of the findings, it was concluded that the host-specific qPCRs are sufficiently robust to be applied in environmental MST studies.

scholarly journals Evaluation of Bovine Feces-Associated Microbial Source Tracking Markers and Their Correlations with Fecal Indicators and Zoonotic Pathogens in a Brisbane, Australia, Reservoir

2013 ◽  
Vol 79 (8) ◽  
pp. 2682-2691 ◽  
Author(s):  
W. Ahmed ◽  
T. Sritharan ◽  
A. Palmer ◽  
J. P. S. Sidhu ◽  
S. Toze
Keyword(s):  
Host Specificity ◽  
Water Samples ◽  
Microbial Source Tracking ◽  
Fecal Pollution ◽  
Decay Rates ◽  
Source Tracking ◽  
Content Type ◽  
Zoonotic Pathogens ◽  
Maximum Value ◽  
Bovine Feces

ABSTRACTThis study was aimed at evaluating the host specificity and host sensitivity of two bovine feces-associated bacterial (BacCow-UCD and cowM3) and one viral [bovine adenovirus (B-AVs)] microbial source tracking (MST) markers by screening 130 fecal and wastewater samples from 10 target and nontarget host groups in southeast Queensland, Australia. In addition, 36 water samples were collected from a reservoir and tested for the occurrence of all three bovine feces-associated markers along with fecal indicator bacteria (FIB),Campylobacterspp.,Escherichia coliO157, andSalmonellaspp. The overall host specificity values of the BacCow-UCD, cowM3, and B-AVs markers to differentiate between bovine and other nontarget host groups were 0.66, 0.88, and 1.00, respectively (maximum value of 1.00). The overall host sensitivity values of these markers, however, in composite bovine wastewater and individual bovine fecal DNA samples were 0.93, 0.90, and 0.60, respectively (maximum value of 1.00). Among the 36 water samples tested, 56%, 22%, and 6% samples were PCR positive for the BacCow-UCD, cowM3, and B-AVs markers, respectively. Among the 36 samples tested, 50% and 14% samples were PCR positive for theCampylobacter16S rRNA andE. coliO157rfbEgenes, respectively. Based on the results, we recommend that multiple bovine feces-associated markers be used if possible for bovine fecal pollution tracking. Nonetheless, the presence of the multiple bovine feces-associated markers along with the presence of potential zoonotic pathogens indicates bovine fecal pollution in the reservoir water samples. Further research is required to understand the decay rates of these markers in relation to FIB and zoonotic pathogens.

scholarly journals Assessment of Giardia and Cryptosporidium spp. as a Microbial Source Tracking Tool for Surface Water: Application in a Mixed-Use Watershed

2014 ◽  
Vol 80 (8) ◽  
pp. 2328-2336 ◽  
Author(s):  
Natalie Prystajecky ◽  
Peter M. Huck ◽  
Hans Schreier ◽  
Judith L. Isaac-Renton
Keyword(s):  
Surface Water ◽  
Host Specificity ◽  
Water Samples ◽  
Environmental Protection Agency ◽  
Current Knowledge ◽  
Microbial Source Tracking ◽  
Source Tracking ◽  
Genomic Sequencing ◽  
Content Type ◽  
Surface Water Samples

ABSTRACTKnowledge of host specificity, combined with genomic sequencing ofGiardiaandCryptosporidiumspp., has demonstrated a microbial source tracking (MST) utility for these common waterborne microbes. To explore the source attribution potential of these pathogens, water samples were collected in a mixed rural-urban watershed in the Township of Langley, in southwestern British Columbia (BC), Canada, over a 2-year period.Cryptosporidiumwas detected in 63% of surface water samples at concentrations ranging from no positive detection (NPD) to 20,600 oocysts per 100 liters.Giardiawas detected in 86% of surface water samples at concentrations ranging from NPD to 3,800 cysts per 100 liters of water. Sequencing at the 18S rRNA locus revealed that 50% ofCryptosporidiumsamples and 98% ofGiardiasamples contained species/genotypes (Cryptosporidium) or assemblages (Giardia) that are capable of infecting humans, based on current knowledge of host specificity and taxonomy.Cryptosporidiumgenotyping data were more promising for source tracking potential, due to the greater number of host-adapted (i.e., narrow-host-range) species/genotypes compared toGiardia, since 98% ofGiardiaisolates were zoonotic and the potential host could not be predicted. This report highlights the benefits of parasite genomic sequencing to complement Method 1623 (U.S. Environmental Protection Agency) and shows thatCryptosporidiumsubtyping for MST purposes is superior to the use ofGiardiasubtyping, based on better detection limits forCryptosporidium-positive samples than forGiardia-positive samples and on greater host specificity amongCryptosporidiumspecies. These additional tools could be used for risk assessment in public health and watershed management decisions.

scholarly journals Development and Evaluation of a Quantitative PCR Assay Targeting Sandhill Crane (Grus canadensis) Fecal Pollution

2012 ◽  
Vol 78 (12) ◽  
pp. 4338-4345 ◽  
Author(s):  
Hodon Ryu ◽  
Jingrang Lu ◽  
Jason Vogel ◽  
Michael Elk ◽  
Felipe Chávez-Ramírez ◽  
...  
Keyword(s):  
Host Specificity ◽  
Quantitative Pcr ◽  
Water Samples ◽  
False Negative ◽  
Environmental Water ◽  
Fecal Pollution ◽  
Source Tracking ◽  
Rrna Gene ◽  
Content Type ◽  
Sandhill Crane

ABSTRACTWhile the microbial water quality in the Platte River is seasonally impacted by excreta from migrating cranes, there are no methods available to study crane fecal contamination. Here we characterized microbial populations in crane feces using phylogenetic analysis of 16S rRNA gene fecal clone libraries. Using these sequences, a novel crane quantitative PCR (Crane1) assay was developed, and its applicability as a microbial source tracking (MST) assay was evaluated by determining its host specificity and detection ability in environmental waters. Bacteria from crane excreta were dominated by bacilli and proteobacteria, with a notable paucity of sequences homologous toBacteroidetesandClostridia. The Crane1 marker targeted a dominant clade of unclassifiedLactobacillalessequences closely related toCatellicoccus marimammalium. The host distribution of the Crane1 marker was relatively high, being positive for 69% (66/96) of the crane excreta samples tested. The assay also showed high host specificity, with 95% of the nontarget fecal samples (i.e.,n= 553; 20 different free-range hosts) being negative. Of the presumed crane-impacted water samples (n= 16), 88% were positive for the Crane1 assay, whereas none of the water samples not impacted by cranes were positive (n= 165). Bayesian statistical models of the Crane1 MST marker demonstrated high confidence in detecting true-positive signals and a low probability of false-negative signals from environmental water samples. Altogether, these data suggest that the newly developed marker could be used in environmental monitoring studies to study crane fecal pollution dynamics.

scholarly journals Culture-Independent Detection of Nontuberculous Mycobacteria in Clinical Respiratory Samples

2016 ◽  
Vol 54 (9) ◽  
pp. 2395-2398 ◽  
Author(s):  
Gianny P. Scoleri ◽  
Jocelyn M. Choo ◽  
Lex E. X. Leong ◽  
Thomas R. Goddard ◽  
Lisa Shephard ◽  
...  
Keyword(s):  
Quantitative Pcr ◽  
Nontuberculous Mycobacteria ◽  
Direct Detection ◽  
Clinical Samples ◽  
Pcr Assay ◽  
Content Type ◽  
Culture Independent ◽  
Quantitative Pcr Assay ◽  
Single Reaction

Culture-based detection of nontuberculousMycobacteria(NTM) in respiratory samples is time consuming and can be subject to overgrowth by nonmycobacterial bacteria. We describe a single-reaction TaqMan quantitative PCR assay for the direct detection of NTM species in clinical samples that is specific, sensitive, and robust.

scholarly journals Performance of Two Quantitative PCR Methods for Microbial Source Tracking of Human Sewage and Implications for Microbial Risk Assessment in Recreational Waters

2012 ◽  
Vol 78 (20) ◽  
pp. 7317-7326 ◽  
Author(s):  
Christopher Staley ◽  
Katrina V. Gordon ◽  
Mary E. Schoen ◽  
Valerie J. Harwood
Keyword(s):  
Risk Assessment ◽  
Quantitative Pcr ◽  
Microbial Source Tracking ◽  
Human Polyomavirus ◽  
Source Tracking ◽  
Specific Marker ◽  
Environmental Waters ◽  
Potential Health ◽  
Microbial Risk Assessment ◽  
Microbial Risk

ABSTRACTBefore new, rapid quantitative PCR (qPCR) methods for assessment of recreational water quality and microbial source tracking (MST) can be useful in a regulatory context, an understanding of the ability of the method to detect a DNA target (marker) when the contaminant source has been diluted in environmental waters is needed. This study determined the limits of detection and quantification of the human-associatedBacteroidessp. (HF183) and human polyomavirus (HPyV) qPCR methods for sewage diluted in buffer and in five ambient, Florida water types (estuarine, marine, tannic, lake, and river). HF183 was quantifiable in sewage diluted up to 10−6in 500-ml ambient-water samples, but HPyVs were not quantifiable in dilutions of >10−4. Specificity, which was assessed using fecal composites from dogs, birds, and cattle, was 100% for HPyVs and 81% for HF183. Quantitative microbial risk assessment (QMRA) estimated the possible norovirus levels in sewage and the human health risk at various sewage dilutions. When juxtaposed with the MST marker detection limits, the QMRA analysis revealed that HF183 was detectable when the modeled risk of gastrointestinal (GI) illness was at or below the benchmark of 10 illnesses per 1,000 exposures, but the HPyV method was generally not sensitive enough to detect potential health risks at the 0.01 threshold for frequency of illness. The tradeoff between sensitivity and specificity in the MST methods indicates that HF183 data should be interpreted judiciously, preferably in conjunction with a more host-specific marker, and that better methods of concentrating HPyVs from environmental waters are needed if this method is to be useful in a watershed management or monitoring context.

scholarly journals Use of Bacteroidales Microbial Source Tracking To Monitor Fecal Contamination in Fresh Produce Production

2013 ◽  
Vol 80 (2) ◽  
pp. 612-617 ◽  
Author(s):  
Kruti Ravaliya ◽  
Jennifer Gentry-Shields ◽  
Santos Garcia ◽  
Norma Heredia ◽  
Anna Fabiszewski de Aceituno ◽  
...  
Keyword(s):  
Fresh Produce ◽  
Fecal Contamination ◽  
Microbial Source Tracking ◽  
Source Tracking ◽  
Rrna Gene ◽  
Specific Marker ◽  
Production Environment ◽  
Content Type ◽  
Food Borne

ABSTRACTIn recent decades, fresh and minimally processed produce items have been associated with an increasing proportion of food-borne illnesses. Most pathogens associated with fresh produce are enteric (fecal) in origin, and contamination can occur anywhere along the farm-to-fork chain. Microbial source tracking (MST) is a tool developed in the environmental microbiology field to identify and quantify the dominant source(s) of fecal contamination. This study investigated the utility of an MST method based onBacteroidales16S rRNA gene sequences as a means of identifying potential fecal contamination, and its source, in the fresh produce production environment. The method was applied to rinses of fresh produce, source and irrigation waters, and harvester hand rinses collected over the course of 1 year from nine farms (growing tomatoes, jalapeño peppers, and cantaloupe) in Northern Mexico. Of 174 samples, 39% were positive for a universalBacteroidalesmarker (AllBac), including 66% of samples from cantaloupe farms (3.6 log10genome equivalence copies [GEC]/100 ml), 31% of samples from tomato farms (1.7 log10GEC/100 ml), and 18% of samples from jalapeño farms (1.5 log10GEC/100 ml). Of 68 AllBac-positive samples, 46% were positive for one of three human-specific markers, and none were positive for a bovine-specific marker. There was no statistically significant correlation betweenBacteroidalesand genericEscherichia coliacross all samples. This study provides evidence thatBacteroidalesmarkers may serve as alternative indicators for fecal contamination in fresh produce production, allowing for determination of both general contamination and that derived from the human host.

scholarly journals Automated Sampling Procedures Supported by High Persistence of Bacterial Fecal Indicators and Bacteroidetes Genetic Microbial Source Tracking Markers in Municipal Wastewater during Short-Term Storage at 5°C

2015 ◽  
Vol 81 (15) ◽  
pp. 5134-5143 ◽  
Author(s):  
R. E. Mayer ◽  
J. Vierheilig ◽  
L. Egle ◽  
G. H. Reischer ◽  
E. Saracevic ◽  
...  
Keyword(s):  
Municipal Wastewater ◽  
Storage Conditions ◽  
Microbial Source Tracking ◽  
Basic Knowledge ◽  
Treated Wastewater ◽  
Source Tracking ◽  
Fecal Indicators ◽  
Content Type ◽  
Automated Sampling ◽  
Sampling Procedures

ABSTRACTBecause of high diurnal water quality fluctuations in raw municipal wastewater, the use of proportional autosampling over a period of 24 h at municipal wastewater treatment plants (WWTPs) to evaluate carbon, nitrogen, and phosphorus removal has become a standard in many countries. Microbial removal or load estimation at municipal WWTPs, however, is still based on manually recovered grab samples. The goal of this study was to establish basic knowledge regarding the persistence of standard bacterial fecal indicators andBacteroidetesgenetic microbial source tracking markers in municipal wastewater in order to evaluate their suitability for automated sampling, as the potential lack of persistence is the main argument against such procedures. Raw and secondary treated wastewater of municipal origin from representative and well-characterized biological WWTPs without disinfection (organic carbon and nutrient removal) was investigated in microcosm experiments at 5 and 21°C with a total storage time of 32 h (including a 24-h autosampling component and an 8-h postsampling phase). VegetativeEscherichia coliand enterococci, as well asClostridium perfringensspores, were selected as indicators for cultivation-based standard enumeration. Molecular analysis focused on total (AllBac) and human-associated geneticBacteroidetes(BacHum-UCD, HF183 TaqMan) markers by using quantitative PCR, as well as 16S rRNA gene-based next-generation sequencing. The microbial parameters showed high persistence in both raw and treated wastewater at 5°C under the storage conditions used. Surprisingly, and in contrast to results obtained with treated wastewater, persistence of the microbial markers in raw wastewater was also high at 21°C. On the basis of our results, 24-h autosampling procedures with 5°C storage conditions can be recommended for the investigation of fecal indicators orBacteroidetesgenetic markers at municipal WWTPs. Such autosampling procedures will contribute to better understanding and monitoring of municipal WWTPs as sources of fecal pollution in water resources.

scholarly journals Microbial Source Tracking Using Quantitative and Digital PCR To Identify Sources of Fecal Contamination in Stormwater, River Water, and Beach Water in a Great Lakes Area of Concern

2018 ◽  
Vol 84 (20) ◽  
Author(s):  
Zachery R. Staley ◽  
Rachel J. Boyd ◽  
Phoenix Shum ◽  
Thomas A. Edge
Keyword(s):  
Great Lakes ◽  
Fecal Contamination ◽  
Digital Pcr ◽  
Microbial Source Tracking ◽  
Source Tracking ◽  
Content Type ◽  
Low Levels ◽  
Areas Of Concern ◽  
Area Of Concern ◽  
The Individual

ABSTRACTAreas of concern (AOCs) around the Great Lakes are characterized by historic and ongoing problems with microbial water quality, leading to beneficial use impairments (BUIs) such as beach postings and closures. In this study, we assessed river and beach sites within the Rouge River watershed, associated stormwater outfalls, and at Rouge Beach. The concentrations ofEscherichia colias well as human- and gull-specific qPCR microbial source tracking (MST) markers were assessed at all sites. A preliminary comparison of digital PCR (dPCR) methodologies for both MST markers was conducted regarding sensitivity and specificity. Within the watershed, the outfalls were found to be a prominent source of human fecal contamination, with two outfalls particularly affected by sewage cross-connections. However, the occurrence of human fecal contamination along Rouge Beach and in the lower portions of the watershed was largely dependent on rain events. Gull fecal contamination was the predominant source of contamination at the beach, particularly during dry weather. The multiplex human/gull dPCR methodology used in this study tended to be more sensitive than the individual quantitative PCR (qPCR) assays, with only a slight decrease in specificity. Both dPCR and qPCR methodologies identified the same predominance of human and gull markers in stormwater and beach locations, respectively; however, the dPCR multiplex assay was more sensitive and capable of detecting fecal contamination that was undetected by qPCR assays. These results demonstrate the dPCR assay used in this study could be a viable tool for MST studies to increase the ability to identify low levels of fecal contamination.IMPORTANCEFecal contamination of recreational water poses a persistent and ongoing problem, particularly in areas of concern around the Great Lakes. The identification of the source(s) of fecal contamination is essential for safeguarding public health as well as guiding remediation efforts; however, fecal contamination may frequently be present at low levels and remain undetectable by certain methodologies. In this study, we utilized microbial source tracking techniques using both quantitative and digital PCR assays to identify sources of contamination. Our results indicated high levels of human fecal contamination within stormwater outfalls, while lower levels were observed throughout the watershed. Additionally, high levels of gull fecal contamination were detected at Rouge Beach, particularly during drier sampling events. Furthermore, our results indicated an increased sensitivity of the digital PCR assay to detect both human and gull contamination, suggesting it could be a viable tool for future microbial source tracking studies.

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