The lab in a box

29th December 2015

Posted By Paul Boughton

Environmental cassettes can be used for all environmental tests, including finger dabs, contact plates and active air monitoring
Bioburden casettes are similar to current filtration cassettes
Sterility cassettes and tubing
The blue light is shined on the cassette to allow the bacterial cells to auto-fluoresce, enabling the light signal to be detected by a CCD camera

Mark Severns on automating key microbiology quality control tests 

The pharmaceutical microbiology QC lab can often be seen as a roadblock to getting pharmaceutical products to market faster. Regulatory requirements demand that microbial testing be performed with in-process and finished product, as well as the manufacturing environment. Samples must be safely taken out of clean areas and taken to the lab where they are painstakingly processed using manual techniques. The time and expense needed to get microbiological results has led many pharmaceutical companies to outsource microbiology, leading to further time delays and also additional costs per test.

Although there are many and varied rapid techniques that attempt to address this issue, there are few that can incorporate the entire catalogue of requirements laid out by pharmaceutical companies. The key need of pharmaceutical manufacturers is that any new method address the entire range of key tests typically carried out in the quality control lab, namely environmental monitoring, bioburden testing, water testing and sterility testing. In addition, any solution should seamlessly fit into the existing processes and offer streamlined validation. This includes providing results in colony forming units (CFUs), mimicking the existing preparation method, and integrating into a LIMS. The optimal solution for the QC lab is a rapid microbiology technology that is essentially a ‘lab in a box’ – a single technology to support the key microbiology tests without significant process changes. Automated technologies, such as the Growth Direct System, offer this type of capability.

Environmental monitoring

For environmental monitoring, it is critical that any new technology support the capture of samples using similar methods. Any new cassettes must be similar to a traditional contact plate. In addition, a protected no growth area around the outside can guard against cross contamination. The media must be the generally accepted media, such as TSA plus lecithin and polysorbate 80 and TSA plus lecithin, P80, histidin and sodium thiosulphate, to sufficiently neutralise residual disinfectants. The cassette itself can therefore be used as a contact plate, finger dab and active air sampling cassette. Because of this, sampling procedures and media are kept the same making validation simpler than often feared.

Bioburden cassettes

Much like the environmental monitoring case, any new bioburden testing method must closely match the existing sample preparation technique. Cassettes should be similar to current filtration cassettes, and use traditional media. There must also be a filtration funnel that includes a membrane to be placed on the cassette following filtration.


There are several critical aspects to the sterility tests that must be replicated with any new method. First, the method needs to be closed loop to ensure no cross-contamination at any time in the process. The test should closely replicate the filter testing currently performed in isolators or biosafety cabinets. Finally, the test must replicate the three conditions of the current sterility test: aerobic at 22.5°C; anaerobic at 32.5C; and aerobic at 32.5°C.

An example of such a method is the Growth Direct sterility test. Samples are filtered using a peristaltic system and the tubing, with the addition of the media using a different channel on the same tubing, capping off the cassette and (in the case of the anaerobic cassette) pulling a toggle to create an anaerobic environment.

Mimicking sample preparation is only part of the solution. To achieve a lab in a box, the samples need to be loaded into an automated technology that can replicate the manual steps performed today. An example technology, the Growth Direct System, takes prepared samples, identifies the correct test for each individual sample, and performs testing at the correct temperature and for the correct incubation time in a fully automated manner, reporting results in about half the time, and alerting the lab to any samples of interest.

Advanced imaging technology detects growing colonies at as few as around 100 cells. Custom algorithms record the CFU counts (or positive in the case of sterility) and provide regular updates as the assay progresses.

Because all samples are sealed during sampling, there is no need for the instrument to be located in the laboratory. The technology is easy to use and CFR 21 part 11 compliant, ensuring data integrity.

The microbiology quality control lab struggles with manual methods and a high workload of tests that are critical to the safety of pharmaceutical products. Introducing a technology such as the Growth Direct System, which can automate and accelerate the key tests without significant changes to current processes, would increase the efficiency of the lab.

For more information, visit

Mark Severns is with Rapid Micro Biosystems





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