scholarly journals Detecting Flavobacterial Fish Pathogens in the Environment Using High-Throughput Community Analysis

2021 ◽  
Author(s):  
Todd Testerman ◽  
Lidia Beka ◽  
Emily Ann McClure ◽  
Stephen R. Reichley ◽  
Stacy King ◽  
...  
Keyword(s):  
Microbial Community ◽  
Early Detection ◽  
Environmental Samples ◽  
Pathogen Detection ◽  
Illumina Miseq ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Molecular Techniques ◽  
Rrna Gene ◽  
Fish Pathogens

Diseases caused by the fish pathogens Flavobacterium columnare and Flavobacterium psychrophilum are major contributors of preventable losses in the aquaculture industry. The persistent and difficult to control infections caused by these bacteria make timely intervention and prophylactic elimination of pathogen reservoirs important measures to combat these disease-causing agents. In the present study, we present two independent assays for detecting these pathogens in a range of environmental samples. Natural water samples were inoculated with F. columnare and F. psychrophilum over five orders of magnitude, and pathogen levels were detected using Illumina MiSeq sequencing and droplet digital PCR. Both detection methods accurately identified pathogen-positive samples and showed good agreement in quantifying each pathogen. Additionally, the real-world application of these approaches was demonstrated using environmental samples collected at a rainbow trout ( Oncorhynchus mykiss ) aquaculture facility. These results show that both methods can serve as useful tools for surveillance efforts in aquaculture facilities, where the early detection of these flavobacterial pathogens may direct preventative measures to reduce disease occurrence. Importance Early detection of a deadly disease outbreak in a population can be the difference between mass mortality or mitigated effects. In the present study, we evaluated and compared two molecular techniques for detecting economically impactful aquaculture pathogens. We demonstrate that one of these techniques, 16S rRNA gene sequencing using Illumina MiSeq technology, provides the ability to accurately detect two freshwater fish pathogens, F. columnare and F. psychrophilum , while simultaneously profiling the native microbial community. The second technique, droplet digital PCR, is commonly used for pathogen detection, and the results obtained using the assays we designed with this method served to validate those obtained using the MiSeq method. These two methods offer distinct advantages. The MiSeq method pairs pathogen detection and microbial community profiling to answer immediate and long-term fish health concerns, while droplet digital PCR method provides fast and highly sensitive detection that is useful for surveillance and rapid clinical responses.

scholarly journals Detecting Flavobacterial Fish Pathogens in the Environment Using High-Throughput Community Analysis

2021 ◽  
Author(s):  
Todd Testerman ◽  
Lidia Beka ◽  
Emily Ann McClure ◽  
Stephen R. Reichley ◽  
Stacy King ◽  
...  
Keyword(s):  
Environmental Samples ◽  
Community Analysis ◽  
Illumina Miseq ◽  
Digital Pcr ◽  
Detection Methods ◽  
Flavobacterium Columnare ◽  
Fish Pathogens ◽  
Preventative Measures ◽  
Disease Occurrence ◽  
Aquaculture Facilities

Diseases caused by the fish pathogens Flavobacterium columnare and Flavobacterium psychrophilum are major contributors of preventable losses in the aquaculture industry. Persistent and difficult to control infections make timely intervention and prophylactic elimination of pathogen reservoirs important mechanisms to combat these disease agents. In this study, we present two independent assays for detecting these pathogens from a range of environmental samples. Natural water samples were inoculated with F. columnare and F. psychrophilum cells and pathogen levels were detected using Illumina MiSeq sequencing and droplet digital PCR. Both detection methods accurately identified pathogen-positive samples and showed good agreement in quantifying each pathogen. The real-world application of these approaches was demonstrated using environmental samples collected at a rainbow trout aquaculture facility. These methods can serve as useful tools for surveillance efforts in aquaculture facilities. Early detection of these flavobacterial pathogens may direct preventative measures in order to reduce disease occurrence.

scholarly journals A Comparison of Blood Pathogen Detection Among Droplet Digital PCR, Metagenomic Next-Generation Sequencing, and Blood Culture in Critically Ill Patients With Suspected Bloodstream Infections

2021 ◽  
Vol 12 ◽  
Author(s):  
Bangchuan Hu ◽  
Yue Tao ◽  
Ziqiang Shao ◽  
Yang Zheng ◽  
Run Zhang ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Blood Culture ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Pathogen Detection ◽  
Bloodstream Infections ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Next Generation ◽  
Generation Sequencing

Metagenomic next-generation sequencing (mNGS) and droplet digital PCR (ddPCR) have recently demonstrated a great potential for pathogen detection. However, few studies have been undertaken to compare these two nucleic acid detection methods for identifying pathogens in patients with bloodstream infections (BSIs). This prospective study was thus conducted to compare these two methods for diagnostic applications in a clinical setting for critically ill patients with suspected BSIs. Upon suspicion of BSIs, whole blood samples were simultaneously drawn for ddPCR covering 20 common isolated pathogens and four antimicrobial resistance (AMR) genes, mNGS, and blood culture. Then, a head-to-head comparison was performed between ddPCR and mNGS. A total of 60 episodes of suspected BSIs were investigated in 45 critically ill patients, and ddPCR was positive in 50 (83.3%), mNGS in 41 (68.3%, not including viruses), and blood culture in 10 (16.7%) episodes. Of the 10 positive blood cultures, nine were concordantly identified by both mNGS and ddPCR methods. The head-to-head comparison showed that ddPCR was more rapid (~4 h vs. ~2 days) and sensitive (88 vs. 53 detectable pathogens) than mNGS within the detection range of ddPCR, while mNGS detected a broader range of pathogens (126 vs. 88 detectable pathogens, including viruses) than ddPCR. In addition, a total of 17 AMR genes, including 14 blaKPC and 3 mecA genes, were exclusively identified by ddPCR. Based on their respective limitations and strengths, the ddPCR method is more useful for rapid detection of common isolated pathogens as well as AMR genes in critically ill patients with suspected BSI, whereas mNGS testing is more appropriate for the diagnosis of BSI where classic microbiological or molecular diagnostic approaches fail to identify causative pathogens.

scholarly journals Comparative Use of Quantitative PCR (qPCR), Droplet Digital PCR (ddPCR), and Recombinase Polymerase Amplification (RPA) in the Detection of Shiga Toxin-Producing E. coli (STEC) in Environmental Samples

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3507
Author(s):  
Mark A. Ibekwe ◽  
Shelton E. Murinda ◽  
Stanley Park ◽  
Amarachukwu Obayiuwana ◽  
Marcia A. Murry ◽  
...  
Keyword(s):  
Quantitative Pcr ◽  
Environmental Samples ◽  
Point Of Care ◽  
Foodborne Pathogen ◽  
Digital Pcr ◽  
Absolute Quantification ◽  
Droplet Digital Pcr ◽  
Recombinase Polymerase Amplification ◽  
High Rate ◽  
E Coli

E. coli O157:H7 is a foodborne pathogen that constitutes a global threat to human health. However, the quantification of this pathogen in food and environmental samples may be problematic at the low cell numbers commonly encountered in environmental samples. In this study, we used recombinase polymerase amplification (RPA) for the detection of E. coli O157:H7, real-time quantitative PCR (qPCR) for quantification, and droplet digital PCR (ddPCR) for absolute and accurate quantification of E. coli O157:H7 from spiked and environmental samples. Primer and probe sets were used for the detection of stx1 and stx2 using RPA. Genes encoding for stx1, stx2, eae, and rfbE were used to quantify E. coli O157:H7 in the water samples. Furthermore, duplex ddPCR assays were used to quantify the pathogens in these samples. Duplex assay set 1 used stx1 and rfbE genes, while assay set 2 used stx2 and eae genes. Droplet digital PCR was used for the absolute quantification of E. coli O15:H7 in comparison with qPCR for the spiked and environmental samples. The RPA results were compared to those from qPCR and ddPCR in order to assess the efficiency of the RPA compared with the PCR methods. The assays were further applied to the dairy lagoon effluent (DLE) and the high rate algae pond (HRAP) effluent, which were fed with diluted DLE. The RPA detected was <10 CFU/mL, while ddPCR showed quantification from 1 to 104 CFU/mL with a high reproducibility. In addition, quantification by qPCR was from 103 to 107 CFU/mL of the wastewater samples. Therefore, the RPA assay has potential as a point of care tool for the detection of E. coli O157:H7 from different environmental sources, followed by quantification of the target concentrations.

scholarly journals The Influence of DNA Extraction and Lipid Removal on Human Milk Bacterial Profiles

2020 ◽  
Vol 3 (2) ◽  
pp. 39 ◽  
Author(s):  
Anna Ojo-Okunola ◽  
Shantelle Claassen-Weitz ◽  
Kilaza S. Mwaikono ◽  
Sugnet Gardner-Lubbe ◽  
Heather J. Zar ◽  
...  
Keyword(s):  
Human Milk ◽  
Dna Extraction ◽  
Bacterial Population ◽  
Illumina Miseq ◽  
Molecular Techniques ◽  
Rrna Gene ◽  
Bacterial Dna ◽  
Dna Recovery ◽  
Culture Independent ◽  
Zymo Research

Culture-independent molecular techniques have advanced the characterization of environmental and human samples including the human milk (HM) bacteriome. However, extraction of high-quality genomic DNA that is representative of the bacterial population in samples is crucial. Lipids removal from HM prior to DNA extraction is common practice, but this may influence the bacterial population detected. The objective of this study was to compare four commercial DNA extraction kits and lipid removal in relation to HM bacterial profiles. Four commercial DNA extraction kits, QIAamp® DNA Microbiome Kit, ZR Fungal/Bacterial DNA MiniPrep™, QIAsymphony DSP DNA Kit and ZymoBIOMICS™ DNA Miniprep Kit, were assessed using milk collected from ten healthy lactating women. The kits were evaluated based on their ability to extract high quantities of pure DNA from HM and how well they extracted DNA from bacterial communities present in a commercial mock microbial community standard spiked into HM. Finally, the kits were evaluated by assessing their extraction repeatability. Bacterial profiles were assessed using Illumina MiSeq sequencing targeting the V4 region of the 16S rRNA gene. The ZR Fungal/Bacterial DNA MiniPrep™ and ZymoBIOMICS™ DNA Miniprep (Zymo Research Corp., Irvine, CA, USA) kits extracted the highest DNA yields with the best purity. DNA extracted using ZR Fungal/Bacterial DNA MiniPrep™ best represented the bacteria in the mock community spiked into HM. In un-spiked HM samples, DNA extracted using the QIAsymphony DSP DNA kit showed statistically significant differences in taxa prevalence from DNA extracted using ZR Fungal/Bacterial DNA MiniPrep™ and ZymoBIOMICS™ DNA Miniprep kits. The only difference between skim and whole milk is observed in bacterial profiles with differing relative abundances of Enhydrobacter and Acinetobacter. DNA extraction, but not lipids removal, substantially influences bacterial profiles detected in HM samples, emphasizing the need for careful selection of a DNA extraction kit to improve DNA recovery from a range of bacterial taxa.

scholarly journals High-throughput 16S rRNA gene sequencing of the microbial community associated with palm oil mill effluents of two oil processing systems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Benedicte Ella Zranseu Aka ◽  
Theodore N’dede Djeni ◽  
Simon Laurent Tiemele Amoikon ◽  
Jan Kannengiesser ◽  
Naaila Ouazzani ◽  
...  
Keyword(s):  
Microbial Community ◽  
Palm Oil ◽  
Microbial Community Composition ◽  
16S Rrna Gene Sequencing ◽  
Illumina Miseq ◽  
Rrna Gene ◽  
Industrial Plants ◽  
Oil Processing ◽  
Microbial Contaminants ◽  
Palm Oil Mill

AbstractPalm Oil Mill Effluents (POME) are complex fermentative substrates which habour diverse native microbial contaminants. However, knowledge on the microbiota community shift caused by the anthropogenic effects of POME in the environment is up to date still to be extensively documented. In this study, the bacterial and archaeal communities of POME from two palm oil processing systems (artisanal and industrial) were investigated by Illumina MiSeq Platform. Despite the common characteristics of these wastewaters, we found that their microbial communities were significantly different with regard to their diversity and relative abundance of their different Amplicon Sequence Variants (ASV). Indeed, POME from industrial plants harboured as dominant phyla Firmicutes (46.24%), Bacteroidetes (34.19%), Proteobacteria (15.11%), with the particular presence of Spirochaetes, verrucomicrobia and Synergistetes, while those from artisanal production were colonized by Firmicutes (92.06%), Proteobacteria (4.21%) and Actinobacteria (2.09%). Furthermore, 43 AVSs of archaea were detected only in POME from industrial plants and assigned to Crenarchaeota, Diapherotrites, Euryarchaeota and Nanoarchaeaeota phyla, populated mainly by many methane-forming archaea. Definitively, the microbial community composition of POME from both type of processing was markedly different, showing that the history of these ecosystems and various processing conditions have a great impact on each microbial community structure and diversity. By improving knowledge about this microbiome, the results also provide insight into the potential microbial contaminants of soils and rivers receiving these wastewaters.

scholarly journals Analysis of the Gull Fecal Microbial Community Reveals the Dominance of Catellicoccus marimammalium in Relation to Culturable Enterococci

2013 ◽  
Vol 80 (2) ◽  
pp. 757-765 ◽  
Author(s):  
Amber M. Koskey ◽  
Jenny C. Fisher ◽  
Mary F. Traudt ◽  
Ryan J. Newton ◽  
Sandra L. McLellan
Keyword(s):  
Microbial Community ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
16S Rrna Gene Sequencing ◽  
Illumina Miseq ◽  
Rrna Gene ◽  
Sequence Comparisons ◽  
Fecal Indicator ◽  
Fecal Samples ◽  
Content Type

ABSTRACTGulls are prevalent in beach environments and can be a major source of fecal contamination. Gulls have been shown to harbor a high abundance of fecal indicator bacteria (FIB), such asEscherichia coliand enterococci, which can be readily detected as part of routine beach monitoring. Despite the ubiquitous presence of gull fecal material in beach environments, the associated microbial community is relatively poorly characterized. We generated comprehensive microbial community profiles of gull fecal samples using Roche 454 and Illumina MiSeq platforms to investigate the composition and variability of the gull fecal microbial community and to measure the proportion of FIB.EnterococcaceaeandEnterobacteriaceaewere the two most abundant families in our gull samples. Sequence comparisons between short-read data and nearly full-length 16S rRNA gene clones generated from the same samples revealedCatellicoccus marimammaliumas the most numerous taxon among all samples. The identification of bacteria from gull fecal pellets cultured on membrane-Enterococcusindoxyl-β-d-glucoside (mEI) plates showed that the dominant sequences recovered in our sequence libraries did not represent organisms culturable on mEI. Based on 16S rRNA gene sequencing of gull fecal isolates cultured on mEI plates, 98.8% were identified asEnterococcusspp., 1.2% were identified asStreptococcusspp., and none were identified asC. marimammalium. Illumina deep sequencing indicated that gull fecal samples harbor significantly higher proportions ofC. marimammalium16S rRNA gene sequences (>50-fold) relative to typical mEI culturableEnterococcusspp.C. marimammaliumtherefore can be confidently utilized as a genetic marker to identify gull fecal pollution in the beach environment.

Development of a Multiplex Droplet Digital PCR Assay for Detection of Enterovirus, Parechovirus, Herpes Simplex Virus 1 and 2 Simultaneously for Diagnosis of Viral CNS Infections

2021 ◽  
Author(s):  
Xunhua Zhu ◽  
Pengcheng Liu ◽  
Lijuan Lu ◽  
Huaqing Zhong ◽  
Menghua Xu ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Pathogen Detection ◽  
Dynamic Range ◽  
Detection System ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Herpes Simplex Virus 1 ◽  
Cns Infections ◽  
Simplex Virus

Abstract Background: Enterovirus (EV), parechovirus (HPeV), herpes simplex virus 1 and 2 (HSV1/2) are common viruses leading to viral central nervous system (CNS) infections which are increasingly predominant but exhibit deficiency in definite pathogen diagnosis with gold-standard quantitative PCR method. Previous studies have shown that droplet digital PCR (ddPCR) has great potential in pathogen detection and quantification especially in low concentration samples.Methods: Targeting four common viruses of EV, HPeV, HSV1, and HSV2 in cerebrospinal fluid (CSF), we developed a multiplex ddPCR assay using probe ratio-based multiplexing strategy, analyzed the performance, and evaluated it in 97 CSF samples collected from patients with suspected viral CNS infections on a two-channel ddPCR detection system.Results: The four viruses were clearly distinguished by their corresponding fluorescence amplitude. The limits of detection for EV, HPeV, HSV1, and HSV2 were 5, 10, 5, and 10 copies per reaction, respectively. The dynamic range was at least four orders of magnitude spanned from 2000 to 2 copies per reaction. The results of 97 tested clinical CSF specimens were identical to those deduced from qPCR/qRT-PCR assays using commercial kits.Conclusion: The multiplex ddPCR assay was demonstrated to be an accurate and robust method which could detect EV, HPeV, HSV1, and HSV2 simultaneously. It provides a useful tool for clinical diagnosis and disease monitoring of viral CNS infections.

scholarly journals Comparison of Quantitative PCR and Droplet Digital PCR Multiplex Assays for Two Genera of Bloom-Forming Cyanobacteria, Cylindrospermopsis and Microcystis

2015 ◽  
Vol 81 (15) ◽  
pp. 5203-5211 ◽  
Author(s):  
Shu Harn Te ◽  
Enid Yingru Chen ◽  
Karina Yew-Hoong Gin
Keyword(s):  
Quantitative Pcr ◽  
Dynamic Range ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Molecular Techniques ◽  
Cyanobacterial Blooms ◽  
Accurate Analysis ◽  
Content Type ◽  
Cyanobacterial Species ◽  
Pcr Multiplex

ABSTRACTThe increasing occurrence of harmful cyanobacterial blooms, often linked to deteriorated water quality and adverse public health effects, has become a worldwide concern in recent decades. The use of molecular techniques such as real-time quantitative PCR (qPCR) has become increasingly popular in the detection and monitoring of harmful cyanobacterial species. Multiplex qPCR assays that quantify several toxigenic cyanobacterial species have been established previously; however, there is no molecular assay that detects several bloom-forming species simultaneously.MicrocystisandCylindrospermopsisare the two most commonly found genera and are known to be able to produce microcystin and cylindrospermopsin hepatotoxins. In this study, we designed primers and probes which enable quantification of these genera based on the RNA polymerase C1 gene forCylindrospermopsisspecies and the c-phycocyanin beta subunit-like gene forMicrocystisspecies. Duplex assays were developed for two molecular techniques—qPCR and droplet digital PCR (ddPCR). After optimization, both qPCR and ddPCR assays have high linearity and quantitative correlations for standards. Comparisons of the two techniques showed that qPCR has higher sensitivity, a wider linear dynamic range, and shorter analysis time and that it was more cost-effective, making it a suitable method for initial screening. However, the ddPCR approach has lower variability and was able to handle the PCR inhibition and competitive effects found in duplex assays, thus providing more precise and accurate analysis for bloom samples.

scholarly journals High-Throughput Detection of Multiple miRNAs and Methylated DNA by Droplet Digital PCR

2021 ◽  
Vol 11 (5) ◽  
pp. 359
Author(s):  
Ning Li ◽  
Pushpa Dhilipkannah ◽  
Feng Jiang
Keyword(s):  
Lung Cancer ◽  
Dna Methylation ◽  
Early Detection ◽  
Cancer Patients ◽  
High Throughput ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Lung Cancer Patients ◽  
Molecular Aberrations ◽  
High Throughput Assay

Altered miRNA expression and DNA methylation have highly active and diverse roles in carcinogenesis. Simultaneous detection of the molecular aberrations may have a synergistic effect on the diagnosis of malignancies. Herein, we develop a high-throughput assay for detecting multiple miRNAs and DNA methylation using droplet digital PCR (ddPCR) coupled with a 96-microwell plate. The microplate-based ddPCR could absolutely and reproducibly quantify 15 miRNAs and 14 DNA methylation sites with a high sensitivity (one copy/µL and 0.1%, respectively). Analyzing sputum and plasma of 40 lung cancer patients and 36 cancer-free smokers by this approach identified an integrated biomarker panel consisting of two sputum miRNAs (miRs-31-5p and 210-3p), one sputum DNA methylation (RASSF1A), and two plasma miRNAs (miR-21-5p and 126) for the diagnosis of lung cancer with higher sensitivity and specificity compared with a single type of biomarker. The diagnostic value of the integrated biomarker panel for the early detection of lung cancer was confirmed in a different cohort of 36 lung cancer patients and 39 cancer-free smokers. The high-throughput assay for quantification of multiple molecular aberrations across sputum and plasma could improve the early detection of lung cancer.

Development of droplet digital PCR assays to quantify genes involved in nitrification and denitrification, comparison with quantitative real-time PCR and validation of assays in vineyard soil

2020 ◽  
pp. 1-14
Author(s):  
Tanja M. Voegel ◽  
Melissa M. Larrabee ◽  
Louise M. Nelson
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Environmental Samples ◽  
Soil Bacteria ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Quantitative Real Time Pcr ◽  
Soil Dna ◽  
Soil C ◽  
Total Bacteria

Quantifying genes in soil is important to relate the abundance of soil bacteria to biogeochemical cycles. Quantitative real-time PCR is widely used for quantification, but its use with environmental samples is limited by poor reaction efficiencies or by PCR inhibition through co-purified soil substances. Droplet digital PCR (ddPCR) is a technology for absolute, sensitive quantification of genes. This study optimized eight ddPCR assays to quantify total bacteria and archaea as well as the nitrification (bacterial and archaeal amoA) and denitrification (nirS, nirK, nosZI, nosZII) genes involved in the generation or reduction of the greenhouse gas nitrous oxide. Detection and quantification thresholds were compared with those of quantitative real-time PCR and were equal to, or improved, in ddPCR. To validate the assays using environmental samples, soil DNA was isolated from two vineyards in the Okanagan valley in British Columbia, Canada, over the 2017 growing season. Soil properties related to the observed gene abundances were determined. Total bacteria, nirK, and nosZII increased with time and the soil C/N ratio and NH4+-N concentration affected total archaea and archaeal amoA negatively. The results, compared with those of other studies, showed that ddPCR is a valid alternative to qPCR to quantify genes involved in nitrification or denitrification.

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