scholarly journals A novel genetic marker for the rapid detection of Bacteroides fragilis in recreational water as a human-specific faecal indicator

2011 ◽  
Vol 9 (2) ◽  
pp. 253-264 ◽  
Author(s):  
Chang Soo Lee ◽  
Jason W. Marion ◽  
Jiyoung Lee
Keyword(s):  
16S Rrna ◽  
Real Time ◽  
Real Time Pcr ◽  
Detection System ◽  
Bacteroides Fragilis ◽  
Human Colon ◽  
Recreational Water ◽  
Recreational Waters ◽  
Pcr Products ◽  
Us Epa

Bacteroides spp. has gained substantial interest among the suggested potential candidates for alternative faecal indicators for untreated recreational waters by the US EPA. Interest in Bacteroides as a faecal indicator is based upon the relative abundance of selected members of the Bacteroides genus in the human colon and human faeces. In this study, we developed a real-time PCR detection system based on gyrase B subunit genes (gyrB) specific to Bacteroides fragilis. The gryB-based method was compared with previously described 16S rRNA-based real-time qPCR methods and evaluated for specificity, sensitivity and robustness in detecting B. fragilis from untreated recreational water impacted by human and non-human faecal sources. The new gyrB-based system only detected B. fragilis, whereas the 16S rRNA-based methods generated cross-amplifications with other Bacteroides and Prevotella species. We used a procedure of prefiltration, filtration, sonication and DNA concentration in order to improve the DNA extraction efficiency and the sensitivity of the real-time PCR while removing interference. The amplification and sequencing of PCR products generated by the gyrB-based method confirmed that gyrB-amplified sequences only contained B. fragilis. This rapid method is useful for quantifying faecal contamination and may assist beach and watershed managers in elucidating possible contamination sources.

scholarly journals Validation of a Novel Diagnostic Approach Combining the VersaTREK™ System for Recovery and Real-Time PCR for the Identification of Mycobacterium chimaera in Water Samples

2021 ◽  
Vol 9 (5) ◽  
pp. 1031
Author(s):  
Roberto Zoccola ◽  
Alessia Di Blasio ◽  
Tiziana Bossotto ◽  
Angela Pontei ◽  
Maria Angelillo ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Limit Of Detection ◽  
Detection System ◽  
Bacterial Load ◽  
Microbial Control ◽  
Hospital Setting ◽  
Sample Volume ◽  
Analytical Sensitivity ◽  
Initial Water

Mycobacterium chimaera is an emerging pathogen associated with endocarditis and vasculitis following cardiac surgery. Although it can take up to 6–8 weeks to culture on selective solid media, culture-based detection remains the gold standard for diagnosis, so more rapid methods are urgently needed. For the present study, we processed environmental M. chimaera infected simulates at volumes defined in international guidelines. Each preparation underwent real-time PCR; inoculates were placed in a VersaTREK™ automated microbial detection system and onto selective Middlebrook 7H11 agar plates. The validation tests showed that real-time PCR detected DNA up to a concentration of 10 ng/µL. A comparison of the isolation tests showed that the PCR method detected DNA in a dilution of ×102 CFU/mL in the bacterial suspensions, whereas the limit of detection in the VersaTREK™ was <10 CFU/mL. Within less than 3 days, the VersaTREK™ detected an initial bacterial load of 100 CFU. The detection limit did not seem to be influenced by NaOH decontamination or the initial water sample volume; analytical sensitivity was 1.5 × 102 CFU/mL; positivity was determined in under 15 days. VersaTREK™ can expedite mycobacterial growth in a culture. When combined with PCR, it can increase the overall recovery of mycobacteria in environmental samples, making it potentially applicable for microbial control in the hospital setting and also in environments with low levels of contamination by viable mycobacteria.

Rapid detection and quantitation of hepatitis B virus DNA by real-time PCR using a new fluorescent (FRET) detection system

2004 ◽  
Vol 30 (2) ◽  
pp. 191-195 ◽  
Author(s):  
Sani Hussein Aliyu ◽  
Muktar Hassan Aliyu ◽  
Hamisu M Salihu ◽  
Surendra Parmar ◽  
Hamid Jalal ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Real Time ◽  
Real Time Pcr ◽  
Rapid Detection ◽  
Detection System ◽  
Hepatitis B Virus Dna ◽  
B Virus

Diagnosis and Causative Species of Visceral Leishmaniasis in Southwest Saudi Arabia

2021 ◽  
Author(s):  
Aymen Abdelhaleem ◽  
Nabil Dhayhi ◽  
Mohamed Salih Mahfouz ◽  
Ommer Daffalla ◽  
Mansour Mubarki ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Visceral Leishmaniasis ◽  
Real Time ◽  
Real Time Pcr ◽  
Leishmania Donovani ◽  
Target Genes ◽  
Sample Volume ◽  
Pcr Products ◽  
Polymerase Chain ◽  
Robust Evidence

Visceral leishmaniasis (VL) is the most severe clinical form of the disease and has been reported in the Jazan region of southwest Saudi Arabia. This study aimed to diagnose VL by real-time polymerase chain reaction (PCR) and the direct agglutination test (DAT) and to identify the causative Leishmania species. A total of 80 participants, including 30 suspected VL patients, 30 healthy endemic control individuals, and 20 malaria disease controls, were enrolled in this study. Blood samples were collected and tested for Leishmania DNA by real-time PCR and for antibody by the DAT. Sequencing of some amplified PCR products was used to identify the causative Leishmania species. The diagnosis of VL was successfully achieved by both real-time PCR and by DAT with 100% sensitivity. Leishmania donovani and Leishmania infantum species were detected by sequencing both by the kDNA and ITS1 target genes, followed a BLASTn search. The detection of VL antibody by the DAT followed by the confirmatory detection of Leishmania DNA in patient blood by PCR could promote the adoption of the much less invasive and more sensitive methods for the routine diagnosis of VL. Further study with high sample volume to evaluate the PCR and the DAT are needed, to generate more robust evidence. Based on the sequencing results, emerging studies on VL should focus on the causative Leishmania species, reservoirs, and vectors that are important in the study area.

scholarly journals Integrated Extreme Real-Time PCR and High-Speed Melting Analysis in 52 to 87 Seconds

2019 ◽  
Vol 65 (2) ◽  
pp. 263-271 ◽  
Author(s):  
Joseph T Myrick ◽  
Robert J Pryor ◽  
Robert A Palais ◽  
Sean J Ison ◽  
Lindsay Sanford ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
High Speed ◽  
Dna Analysis ◽  
Point Of Care ◽  
Turnaround Time ◽  
Single Nucleotide Variants ◽  
Cycle Times ◽  
Pcr Products ◽  
Melting Analysis

Abstract BACKGROUND Extreme PCR in &lt;30 s and high-speed melting of PCR products in &lt;5 s are recent advances in the turnaround time of DNA analysis. Previously, these steps had been performed on different specialized instruments. Integration of both extreme PCR and high-speed melting with real-time fluorescence monitoring for detection and genotyping is presented here. METHODS A microfluidic platform was enhanced for speed using cycle times as fast as 1.05 s between 66.4 °C and 93.7 °C, with end point melting rates of 8 °C/s. Primer and polymerase concentrations were increased to allow short cycle times. Synthetic sequences were used to amplify fragments of hepatitis B virus (70 bp) and Clostridium difficile (83 bp) by real-time PCR and high-speed melting on the same instrument. A blinded genotyping study of 30 human genomic samples at F2 c.*97, F5 c.1601, MTHFR c.665, and MTHFR c.1286 was also performed. RESULTS Standard rapid-cycle PCR chemistry did not produce any product when total cycling times were reduced to &lt;1 min. However, efficient amplification was possible with increased primer (5 μmol/L) and polymerase (0.45 U/μL) concentrations. Infectious targets were amplified and identified in 52 to 71 s. Real-time PCR and genotyping of single-nucleotide variants from human DNA was achieved in 75 to 87 s and was 100% concordant to known genotypes. CONCLUSIONS Extreme PCR with high-speed melting can be performed in about 1 min. The integration of extreme PCR and high-speed melting shows that future molecular assays at the point of care for identification, quantification, and variant typing are feasible.

Determining Viability of M. ulcerans by 16S rRNA RT Reverse Transcriptase Real-Time PCR

2021 ◽  
pp. 81-86
Author(s):  
Marcus Beissner ◽  
Richard Odame Phillips ◽  
Gisela Bretzel
Keyword(s):  
16S Rrna ◽  
Reverse Transcriptase ◽  
Real Time ◽  
Real Time Pcr

Evaluation of real-time PCR targeting the 16S rRNA and recA genes for the enumeration of bifidobacteria in probiotic products

2007 ◽  
Vol 113 (3) ◽  
pp. 351-357 ◽  
Author(s):  
L. Masco ◽  
T. Vanhoutte ◽  
R. Temmerman ◽  
J. Swings ◽  
G. Huys
Keyword(s):  
16S Rrna ◽  
Real Time ◽  
Real Time Pcr ◽  
Pcr Targeting

Monitoring of Microbial Community Inhabiting a Low-Grade Copper Sulphide Ore by Quantitative Real-Time PCR Analysis of 16S rRNA Genes

2007 ◽  
Vol 20-21 ◽  
pp. 539-542 ◽  
Author(s):  
Francisco Remonsellez ◽  
F. Galleguillos ◽  
Sonestie Janse van Rensburg ◽  
G.F. Rautenbach ◽  
Pedro A. Galleguillos ◽  
...  
Keyword(s):  
16S Rrna ◽  
Real Time ◽  
Real Time Pcr ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Low Grade ◽  
Copper Sulphide ◽  
Quantitative Real Time Pcr ◽  
Sulphide Ore ◽  
Heap Bioleaching

Microbial heap bioleaching is being used as an industrial process to recover copper from low grade ores. It is known that a consortium of different microorganisms participates in this process. Therefore identification and quantification of communities inhabiting heap bioleaching operations is a key step for understanding the dynamics and role of these microorganisms in the process. A quantitative real-time PCR approach was used to investigate the microbial dynamics in this process. To study the microbial population inhabiting a low-grade copper sulphide ore bioleaching industrial heap process at Escondida Mine in Chile, 16S rRNA genetic libraries were constructed using bacterial and archaeal universal primers. Phylogenetic analyses of sequences retrieved from genetic libraries showed that the community is mainly composed by microoganisms related to Acidithiobacillus ferrooxidans (2 strains), Acidithiobacillus thiooxidans, Leptospirillum ferrooxidans, Leptospirillum ferriphilum and the archaea Ferroplasma. Specific primers for real-time PCR determination were designed and tested to amplify each of the sequences obtained by cloning. Standard curves for real time PCR were performed using plasmid DNA from selected clones. This methodology is actually being used to monitor relevant microorganisms inhabiting this low-grade copper sulphide ore bioleaching industrial heap.

scholarly journals Different Real-Time PCR Formats Compared for the Quantitative Detection of Human Cytomegalovirus DNA

1999 ◽  
Vol 45 (11) ◽  
pp. 1932-1937 ◽  
Author(s):  
Andreas Nitsche ◽  
Nina Steuer ◽  
Christian Andreas Schmidt ◽  
Olfert Landt ◽  
Wolfgang Siegert
Keyword(s):  
Real Time ◽  
Human Cytomegalovirus ◽  
Real Time Pcr ◽  
Detection System ◽  
Quantitative Detection ◽  
Fluorescence Signal ◽  
Hybridization Probe ◽  
Sequence Detection ◽  
Hybridization Probes ◽  
Assay Time

Abstract Background: The aim of this study was to compare the ABI PRISM 7700 Sequence Detection System and the LightCycler to develop a quantitative real-time PCR assay for the detection of human cytomegalovirus (HCMV) DNA suitable for routine hospital application. Methods: We used one exonuclease probe and five different hybridization probe sets as sequence-specific fluorescence detection formats. For the exonuclease assay and two hybridization probe sets, reproducibility and the detection limit were determined. To keep the total assay time to a minimum, we gradually shortened individual reaction steps on both instruments. Results: The exonuclease assay can be interchangeably performed on the 7700 and the LightCycler. No change of reaction conditions is required, except for the addition of bovine serum albumin to the LightCycler reaction. The shortest possible total assay time is 80 min for the ABI PRISM 7700 Sequence Detection System and 20 min for the LightCycler. When the LightCycler is used, the exonuclease probe can be replaced by a set of hybridization probes. All assays presented here detected HCMV DNA in a linear range from 101 to 107 HCMV genome equivalents/assay (r &gt;0.995) with low intraassay (&lt;5%) and interassay (&lt;10%) variation. Conclusions: The ABI PRISM 7700 Sequence Detection System as well as the LightCycler are useful instruments for rapid and precise online PCR detection. Moreover, the two principles of fluorescence signal production allow HCMV quantification with the same accuracy.

scholarly journals Characterization and Event Specific-Detection by Quantitative Real-Time PCR of T25 Maize Insert

2005 ◽  
Vol 88 (2) ◽  
pp. 536-546 ◽  
Author(s):  
Cécile Collonnier ◽  
Alexandra Schattner ◽  
Georges Berthier ◽  
Francine Boyer ◽  
Géraldine Coué-Philippe ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Detection System ◽  
Integration Site ◽  
Ribosomal Gene ◽  
Cauliflower Mosaic Virus ◽  
Plant Genome ◽  
35S Promoter ◽  
Specific Detection ◽  
A Genome

Abstract T25 is one of the 4 maize transformation events from which commercial lines have so far been authorized in Europe. It was created by polyethylene glycol-mediated transformation using a construct bearing one copy of the synthetic pat gene associated with both promoter and terminator of the 35S ribosomal gene from cauliflower mosaic virus. In this article, we report the sequencing of the whole T25 insert and the characterization of its integration site by using a genome walking strategy. Our results confirmed that one intact copy of the initial construct had been integrated in the plant genome. They also revealed, at the 5′ junction of the insert, the presence of a second truncated 35S promoter, probably resulting from rearrangements which may have occurred before or during integration of the plasmid DNA. The analysis of the junction fragments showed that the integration site of the insert presented high homologies with the Huck retrotransposon family. By using one primer annealing in the maize genome and the other in the 5′ end of the integrat ed DNA, we developed a reliable event-specific detection system for T25 maize. To provide means to comply with the European regulation, a real-time PCR test was designed for specific quantitation of T25 event by using Taqman® chemistry.

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