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Pei, A., Oberdorf, W., Nossa, C., Agarwal, A., Chokshi, P., Gerz, E., Jin, Z., Lee, P., Yang, L., Poles, M., Brown, S., Sotero, S., DeSantis, T., Brodie, E., Nelson, K. and Pei, Z. (2010) Diversity of 16s rRNA Genes within Individual Prokaryotic Genomes. Applied and Environmental Microbiology, 76, 3886-3897.
https://doi.org/10.1128/AEM.02953-09

has been cited by the following article:

• TITLE: A Direct Droplet Digital PCR Method for E. coli Host Residual DNA Quantification

  AUTHORS: Jeremy Anderson, Musaddeq Hussain

  KEYWORDS: E. coli Host, Host Residual DNA, Droplet Digital PCR, Direct Method, Biologic Drugs, Injectable Drug

  JOURNAL NAME: Pharmacology & Pharmacy, Vol.9 No.4, April 30, 2018

  ABSTRACT: Injectable drugs manufactured in E. coli must be tested for host residual DNA (hr DNA) impurity in ensuring drug purity and safety. Because of low allowable hr DNA as impurity, highly sensitive methods are needed. Droplet digital PCR (ddPCR) is a new method where the reaction is partitioned into about 20,000 nanoliter-sized droplets and each droplet acts as individual PCR reaction. After completion of end-point PCR, droplets are analyzed for fluorescence and categorized as positive or negative and DNA quantified using Poisson statistics. Here we describe development of a direct E. coli hr DNA dd PCR method where the drug is directly added to the ddPCR reaction. We show that the ddPCR method has acceptable precision and high accuracy, works with different biologic drugs, and compared to qPCR shows higher tolerance of drug matrices. The method does not require DNA extraction or standard curves for quantification of hr DNA in unknown samples.