Real-time quantitative PCR with gene probe, fluorochrome and flow cytometry for microorganism analysis

2005 ◽  
Vol 7 (3) ◽  
pp. 257 ◽  
Author(s):  
Pei-Shih Chen ◽  
Chih-Shan Li
Keyword(s):  
Flow Cytometry ◽  
Real Time ◽  
Quantitative Pcr ◽  
Gene Probe ◽  
Real Time Quantitative Pcr

scholarly journals Flow Cytometry and Real-Time Quantitative PCR as Tools for Assessing Plasmid Persistence

2014 ◽  
Vol 80 (17) ◽  
pp. 5439-5446 ◽  
Author(s):  
Wesley Loftie-Eaton ◽  
Allison Tucker ◽  
Ann Norton ◽  
Eva M. Top
Keyword(s):  
Flow Cytometry ◽  
Real Time ◽  
Quantitative Pcr ◽  
High Throughput ◽  
Performance Criteria ◽  
Plate Count ◽  
Real Time Quantitative Pcr ◽  
Advantages And Disadvantages ◽  
Free Cells ◽  
Loss Rates

ABSTRACTThe maintenance of a plasmid in the absence of selection for plasmid-borne genes is not guaranteed. However, plasmid persistence can evolve under selective conditions. Studying the molecular mechanisms behind the evolution of plasmid persistence is key to understanding how plasmids are maintained under nonselective conditions. Given the current crisis of rapid antibiotic resistance spread by multidrug resistance plasmids, this insight is of high medical relevance. The conventional method for monitoring plasmid persistence (i.e., the fraction of plasmid-containing cells in a population over time) is based on cultivation and involves differentiating colonies of plasmid-containing and plasmid-free cells on agar plates. However, this technique is time-consuming and does not easily lend itself to high-throughput applications. Here, we present flow cytometry (FCM) and real-time quantitative PCR (qPCR) as alternative tools for monitoring plasmid persistence. For this, we measured the persistence of a model plasmid, pB10::gfp, in threePseudomonashosts and in known mixtures of plasmid-containing and -free cells. We also compared three performance criteria: dynamic range, resolution, and variance. Although not without exceptions, both techniques generated estimates of overall plasmid loss rates that were rather similar to those generated by the conventional plate count (PC) method. They also were able to resolve differences in loss rates between artificial plasmid persistence assays. Finally, we briefly discuss the advantages and disadvantages for each technique and conclude that, overall, both FCM and real-time qPCR are suitable alternatives to cultivation-based methods for routine measurement of plasmid persistence, thereby opening avenues for high-throughput analyses.

Durability of complete remission by moxetumomab pasudotox (HA22 or CAT-8015) assessed by clone-specific real-time quantitative PCR (RQ-PCR).

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 2503-2503
Author(s):  
Robert J. Kreitman ◽  
Evgeny Arons ◽  
Jeffrey Sapolsky ◽  
Laura Roth ◽  
Hong Zhou ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Real Time ◽  
Quantitative Pcr ◽  
Hairy Cell Leukemia ◽  
Hairy Cell ◽  
Cell Leukemia ◽  
Real Time Quantitative Pcr ◽  
Recombinant Immunotoxin

2503^ Background: The anti-CD22 recombinant immunotoxin moxetumomab pasudotox, also known as HA22 or CAT-8015, was recently reported in phase I testing to achieve complete remissions (CRs) in 13 (46%) of 28 patients with relapsed/refractory hairy cell leukemia (HCL); 3 of 13 patients have relapsed. Methods: To complete this trial, 20 additional patients received the highest dose level (50 µg/Kg every other day x 3 doses); none of the 48 HCL patients had dose-limiting toxicity (DLT). Results: Of the first 42 patients with >6 mo of follow up off-treatment, 23 (55%) had CRs, with an overall response rate of 88%. Of the 23 CRs, 21 were evaluable for minimal residual disease (MRD) using flow cytometry of blood and immunohistochemistry of the bone marrow biopsy, and 17 (81%) were negative. Of these 17 patients, 11 (65%) were negative by bone marrow aspirate (BMA) flow cytometry. PCR using consensus primers for the heavy chain immunoglobulin (IgH) rearrangement was less specific than flow cytometry of blood, since IgH rearrangements of normal B cells, which recovered rapidly after immunotoxin treatment, were also amplified. For better MRD detection in blood, patient IgH sequences were cloned and sequence specific primers and probes designed for real-time quantitative PCR (RQ-PCR). RQ-PCR of blood was negative in 6 (100%) of 6 patients achieving flow-negativity in both blood and BMA and positive in 3 (100%) of 3 patients flow-negative in blood but not BMA (p=0.01). No relapses from CR have been observed in 10 patients who became RQ-PCR-negative in blood or flow-negative in BMA, with 5-38 (median 11) mo of follow-up. Conclusions: We conclude that clone-specific RQ-PCR is the most sensitive blood test for MRD in our HCL patients after moxetumomab pasudotox, and could be used to assess the possibility of long-term molecular remissions. We believe these results, including durable CRs without DLT, support a pivotal trial in which moxetumomab pasudotox is compared with alternative therapy. Note: this summary contains investigator reported data. This study was funded by MedImmune, LLC, and supported by NCI’s Intramural Research Program and the Hairy Cell Leukemia Research Foundation.

scholarly journals Quantification and Stability of Human Adenoviruses and Polyomavirus JCPyV in Wastewater Matrices

2006 ◽  
Vol 72 (12) ◽  
pp. 7894-7896 ◽  
Author(s):  
Silvia Bofill-Mas ◽  
Nestor Albinana-Gimenez ◽  
Pilar Clemente-Casares ◽  
Ayalkibet Hundesa ◽  
Jesus Rodriguez-Manzano ◽  
...  
Keyword(s):  
Real Time ◽  
Quantitative Pcr ◽  
High Stability ◽  
Wastewater Sludge ◽  
Human Polyomavirus ◽  
Sewage Effluent ◽  
Viral Contamination ◽  
Human Adenoviruses ◽  
Urban Sewage ◽  
Real Time Quantitative Pcr

ABSTRACT Human adenoviruses (HAdV) and human polyomavirus JCPyV have been previously proposed as indicators of fecal viral contamination in the environment. Different wastewater matrices have been analyzed by applying real-time quantitative PCR procedures for the presence, quantity, and stability of a wide diversity of excreted HAdV and JCPyV. High quantities of HAdV and JCPyV were detected in sewage, effluent wastewater, sludge, and biosolid samples. Both viruses showed high stability in urban sewage. These results confirm the suitability of both viruses as indicators of human fecal viral pollution.

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