Choose the Right Rapid Microbial Method For Your Needs
The use of rapid microbiological methods (RMMs) are quickly gaining favor in the pharmaceutical, biotech, home and personal care, and cosmetic manufacturing industries. Combining this BioPhorum article and our experience assisting labs in a wide variety of industries, we have compiled this step-by-step guide to help you select the best rapid microbial method for your lab.
Microbiology quality control departments should identify the key drivers and requirements that are most important to their workflow and business. Requirements such as sample compatibility, vendor expertise, and ease of implementation can vary from site to site or organization to organization.
Consider What’s Available on the Market →
- Identify available rapid microbial testing methods
- Determine which are compatible with your goals and manufacturing processes
- Can they be used on both sterile and non-sterile product testing?
Compare Technologies →
- Compare their strengths and weaknesses
- Are they qualitative or quantitative?
- What is the detection technology they employ?
Develop a Business Case →
- Present your findings to key decision makers
- Use our Financial Impact Assessment tool to build your case by outlining the rationale behind your selection and the associated risks, costs, and ROI
Plan Your Validation Strategy →
- Gather the information you need to successfully execute your chosen technology
- Establish contact with regulatory agencies, if possible
- Remember that in order for RMMs to be approved for routine testing, they must first be validated
The final step is to engage the RMM practice globally to all production facilities within your organization. Although this may seem like a daunting task, we’ve seen successful implementation from industry leaders in both the sterile and non-sterile markets. As the adoption of rapid microbial detection methods continues to increase, it's more important than ever that vendors become more than just instrument suppliers, they become partners throughout the entire process. Thanks to its high-capacity, automated instruments, Celsis® is purposely designed to enable testing flexibility and maximize your lab’s efficiency.
- Drivers and Implementation Framework
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Rapid Microbiological Methods: Key Considerations
- Considerations When Choosing a Rapid Method
- ARMM Technology Comparison
- The RMM Product Matrix
- Qualitative Technologies
ATP-Bioluminescence
ATP-bioluminescence utilizes a naturally occurring reaction which occurs in the presence of adenosine triphosphate (ATP), when the luciferase enzyme converts luciferin into oxyluciferin. As ATP is present in all living bacterial, fungal, and yeast cells, and that this reaction only occurs when ATP is present, allows for the detection of microbiological contamination in a sample. The light produced via this reaction is automatically detected by Celsis luminometers. This reaction is also the same reaction which gives fireflies their famous glow.
CO2 Monitoring
CO2 Monitoring is the qualitative measurement of the increasing of CO2 levels as an indicator of microbial growth inside a closed vial. Changing CO2 levels inside the closed vial will initiate a change in the pH of the vial, which changes the color of an indicator on the vial containing the sample. An instrument measures the change in this indicator, resulting in a decrease in pH levels, to report whether a contamination is present.
PCR-based Selective Detection
In PCR-based Selective Detection, bacterial are detected by targeting specific conserved regions of the bacterial or fungi/yeast genomes. The 16s rRNA coding region for bacteria and 18s sRNA coding region for fungi/yeasts are amplified using PCR. The amplified fragments are then detected to indicate the presence of a contamination. This technology is often employed specifically for mycoplasma, as these are not recovered through traditional methods for bacteria, yeasts, and molds. This assay can be very sensitive; however, it requires a considerable amount of manual preparation with very tight experimental protocol parameters. - Quantitative Technologies
Cytometry-Based Detection
Flow Cytometry-based detection is typically used for the measurement of cells. Flow cytometry is conducted by focusing cells into a narrow stream, or “single file”, in a sheath fluid. Photomultipliers detect light scattering and fluorescence, which gives information about the cell’s size and morphology. Solid phase cytometry is similar, except the sample is first filtered through a membrane. Microbes that remain on the filter are labeled with a fluorophore, which are then scanned by the laser to detect microorganisms but also fluorescent particles.
Fluorescence Assisted Enumeration
Fluorescence- assisted enumeration is an imaging-based technology performed through visual counting of fluorescently labeled colonies on a membrane. Similar to solid phase cytometry, microorganisms captured on a filter are directly labeled with a non-fluorescent substrate which is cleaved by living microorganisms and taken into the cell. Only living cells will fluoresce, but these technologies still require a user to perform enumeration. These systems are routinely able to detect microcolonies, comprised of multiple cells or colony forming units, and may have difficulty detecting individual cells.
Automated Colony Counters: Autofluorescence Assisted Enumeration
Autofluorescence based colony counters are imaging-based technologies that utilize naturally occurring fluorescence when colonies of microorganisms are exposed to light of a specific wavelength. In these systems, plated samples are exposed to a narrow wavelength of this high-powered light, their momentary autofluorescence is captured by a charged couple device (CCD) as data. An image is rendered from this data. The resulting images are either manually reviewed to determine if contamination is present in the form of glowing colonies, or an algorithm is employed to identify colonies from the background via signal to noise ratios. One drawback to these instruments is that the repeated exposure to this high-powered light generates heat in the sample being imaged, which may impact recovery over time.
Automated Colony Counter/ Non-fluorescence Assisted Enumeration
Non-fluorescence assisted enumeration, or automated colony-counting is image-based enumeration which does not utilize fluorescent dyes or stains. Some technologies utilize algorithm-based image analysis to predict colonies; while others also require manual enumeration. Since these instruments do not utilize any fluorescence to discern colonies at very early stages in their growth, or to discern them from the background, it can be difficult for the imaging system to discern individual cells against microcolonies.
- Qualitative Technologies
- Celsis Advance II™
- Celsis Accel®
- Celsis Adapt™
- Business Case Tools and Resources
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Validation Resources
- Celsis Validation Support and Services Overview (tech sheet)
- Celsis® For Sterility: Validating a 7-Day Direct Inoculation Sterility Test Using the Celsis Advance
- Celsis® For Sterility: Validating a 7-Day Membrane Filtration Sterility Test
- STAT Results for STAT Samples: Implementing Modern Rapid Micro Methods
- Case Study Overview: How to Gain Regulatory Approval for a Rapid Sterility Test
- Regulatory Resources
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Case Studies and Testimonials
- Rapid ATP-Bioluminescence for Non-sterile Product Testing: Roadmap to Implementation (webinar)
- Unilever’s Global Rollout of Celsis AMPiScreen® Brings Expected, and Unexpected, Benefits (case study)
- The Journey of Implementing a Rapid Sterility Test: A summary of the collaborative efforts between Charles River and Roche Diagnostics
- Building a Strong Foundation for AstraZeneca’s House of Rapid Sterility
Ready to start?
Our experts can help identify which method is best for your lab and assist with product validation programs, regulatory compliance guidance, and troubleshooting technical issues.
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