The Rapid Micro Blog

Our blog will keep you informed of new and noteworthy technologies, reviews of recent publications and presentations, upcoming conferences and training events, and what's changing in the rapid and alternative microbiological methods world.

Rapid Methods Session 1 at the PDA Global Microbiology Conference

This is the first of two rapid method sessions at the PDA Micro Conference. The first speaker was Michele J. Storrs-Mabilat, PhD, Global Scientific Partnerships Manager, Industrial Microbiology Division, bioMerieux, Inc. She presented information on a novel rapid and automated prototype system for the microbiological monitoring of sterile pharmaceutical environments. The Midass system was introduced, and Midass is an acronym for microbial detection in air system for space. This technology was originally developed for use by astronauts on route to and from Mars, where the air in the space capsule will recirculate for a period of up to 3 years, and there will be a need to assess the microbiological state of the capsule environment during the journey.

For the pharma industry, the Midass system is a complete system for monitoring surfaces, personnel and air. The system utilizes a peppermill-type collection device for air sampling, cellular lysis and nucleic acid purification. A separate NASBA card, which contains primers and probes/beacons, is used to amplify the purified rRNA targets. NASBA is used instead of conventional DNA/PCR amplification because RNA is a better predictor of cellular viability, is not susceptible to contamination by extraneous DNA, and the amplification reaction is carried out at a single temperature instead of multiple temperatures as is required by PCR. Amplification takes place in 60-90 minutes, and the system will detect both bacteria and fungi. The time to result is 3 hours, but there is an opportunity to reduce this time in the future. A table-top instrument is used to process the peppermill and the amplification card.

Total viable counts are obtained not in the form of colony forming units (cfu), but in gene copies or genomic equivalents (Geqs). Sensitivity is estimated at 1 cfu (or 1 Geq) per cubic meter of air or per 25 square cm for fungi, and 20 cfu (20 Geqs) per 25 square cm for bacteria (work is still underway to determine the sensitivity for bacteria in air). Initial testing shows encouraging equivalence between a cfu and a Geq. Finally, the system is considered to be non-destructive, where the purified nucleic acid material may be stored for further analysis, such as microbial identification.

The second speaker was Gene Zhang, PhD, Principal Scientist, Bayer Healthcare Pharmaceutical, who presented a Case Study on Validating a Microbial ID System to Meet the New Regulatory Requirements for Part 11.

There are a number of microbial identification rapid methods systems available and many are operating via computerized systems. The pharma industry is now expected to ensure that the data management capabilities and electronic records for these types of systems meet Part 11 compliance. In fact, FDA warning letters have included reference to computer systems that have not been validated against the expectations to Part 11 requirements. Dr. Zhang reviewed how a firm can meet these requirements and used a rapid nucleic acid amplification identification system based on 16S rRNA sequencing as an example.

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