quality assurance

On-site, In-house Environmental Monitoring to Obtain Species-Level Microbial Identification

Posted on by Michele Arduengo

Loss of life and serious illness from contamination of manufactured products that are consumed as food or used in medical procedures illustrate the need to prevent contamination events rather than merely detect them after the fact.  High-profile news stories have described contamination events in compounding pharmacies (1), food processing and packaging plants (2) and medical device manufacturers (3). Although contamination in manufacturing settings can be physical, chemical, or biological, this article will focus environmental monitoring to determine the quality of a manufacturing facility with respect to microbial contamination.

Scientist in pharmaceutical manufacturing facility performing environmental monitoring.

To ensure that the products they produce and package are manufactured in a high-quality, contaminant-free environment, many industries are required to establish routine environmental monitoring programs. Samples are collected from all potential sources of contamination in the production environment including air, surfaces, water supplies and people. Routine monitoring is essential to detect trends such as increases in potential pathogens over time or the appearance of new species that have not been seen before so that contamination events can be prevented.

Because environmental monitoring requires identification to the level of the species, most environmental monitoring programs will collect samples and then send them off to a facility to be sequenced for genomic identification of any microbial species. Such genotypic analysis involves DNA sequencing of ribosomal RNA (rRNA) genes to determine the taxonomic classification of bacteria and fungi. In this method, informative sections of the rRNA genes are amplified by PCR; the PCR products sequenced; the sequence is compared to reference libraries; and the results interpreted to make a species-level identification for a given microbial isolate.

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Maximize Your Time in the Lab: Improve Experimental Reproducibility with Thaw-and-Use Cells

Posted on by Michele Arduengo

Many cell biology researchers can name their department’s  or institutions’s “cell culture wizard”—the technician with 20+ years of experience whose cell cultures are always free from contamination, exhibit reliable doubling rates and show no phenotype or genotype weirdness. Cell culture takes skill and experience. Primary cell culture can be even more difficult still, and many research and pharmaceutical applications require primary cells.

Yet, among the many causes of failure to replicate study results, variability in cell culture stands out (1). Add to the normal challenges of cell culture a pandemic that shut down cell culture facilities and still limits when and how often researchers can monitor their cell culture lines, and the problem of cell culture variability is magnified further.

Treating Cells as Reagents

A good way to reduce variability in cell-based studies is to use the thaw-and-use frozen stock approach. This involves freezing a large batch of “stock” cells, then performing quality control tests to ensure they respond appropriately to treatment. Then whenever you need to perform an assay, just thaw another vial of cells from that batch and begin your assay—just like an assay reagent! This approach eliminates the need to grow your cells to a specific stage, which could take days and introduce more variability.

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RNA Extraction for Clinical Testing—Do Not Try this with Home-brew

Posted on by Michele Arduengo

This blog was written with much guidance from Jennifer Romanin, Senior Director IVD Operations and Global Service and Support, and Ron Wheeler, Senior Director, Quality Assurance and Regulatory Affairs at Promega.

A Trip Down Memory Lane

Back in the day when we all walked two miles uphill in the snow to get to our laboratories, RNA and DNA extraction were home-brew experiences. You made your own buffers, prepped your own columns and spent hours lysing cells, centrifuging samples, and collecting that fluorescing, ethidium bromide-stained band of RNA in the dark room from a tube suspended over a UV box. Just like master beer brewers tweak their protocols to produce better brews, you could tweak your methodology and become a “master isolater” of RNA. You might get mostly consistent results, but there was no guarantee that your protocol would work as well in the hands of a novice.

Enter the biotechnology companies with RNA and DNA isolation kits—kits and columns manufactured under highly controlled conditions delivering higher quality and reproducibility than your home-brew method. These systems have enabled us to design ever more sensitive downstream assays–assays that rely on high-quality input DNA and RNA, like RT-qPCR assays that can detect the presence of a specific RNA molecule on a swab containing only a few hundred cells. With these assays, contaminants from a home-brew isolation could result in false positives or false negatives or simply confused results. Reagents manufactured with pre-approved standard protocols in a highly controlled environment are critical for ultra sensitive tests and assays like the ones used to detect SARS-CoV-2 (the virus that causes COVID-19).

The Science of Manufacturing Tools for Scientists

There are several criteria that must be met if you are producing systems that will be sent to different laboratories, used by different people with variable skill sets, yet yield results that can be compared from lab to lab.

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