Automation Justification in Microbiology Labs

Growcells.com produces more than 120 liters of agar-based media daily. One of the company’s key services is the daily production of over 400 bioassay plates the size of notebooks (245mm x 245mm) each containing in excess of 300 ml of media.

“These bioassay trays have a large surface area, are designed for robotic colony picking, so they introduce different challenges than pouring agar in a more commonly used small 60mm or 100mm Petri dish. For the bioassay trays, the media has to be very consistent in temperature as it is being poured so it doesn’t harden too quickly or unevenly,” explains Rehan, whose customers typically use $200,000 lab robotic systems to handle the finished trays when conducting research.

“The media has to be extremely clear, perfectly leveled and dried before using the trays,” says Rehan. “Otherwise a $20 tray might throw off the calibration of a robot and cause costly delays and expensive recalibration problems for our customers.”

When considering media/agar sterilizers, Rehan was looking for equipment that was reliable, offered higher-throughput, was compact and easy to use. After trying media preparators from other companies, he selected a Masterclave 60.

“The unit is intuitively designed, making it seamless to incorporate in our production process,” says Rehan. “The media dispensing port located at the bottom of the tank allows gravity flow (instead of air compressors) to move the media from the tank via a standard peristaltic pump during dispensing.”

“It’s our workhorse; we would not be in business without it,” says Rehan, who has been using the unit every day for nearly three years. “Other media sterilizers didn’t have user friendliness, easy-to-use controls, reliability or printout. When the media would not reach the right sterilization temperature, our plates would develop contamination. This would cost us time, money and aggravation. There was a constant need to monitor the temperature to ensure that sterilization temperature was being achieved and for the appropriate time period.”

“Now, with temperature control, every batch is a flawless product,” says Rehan. “We also have printed reports that document the temperature levels reached by all media. The antibiotics are added at the optimal temperature, and we have validated this unit several times. This has become critical for our internal quality control and part of the documentation we provide our customers.”

Autopreparators provide critical benefits compared to manual methods.

Critical Points: Media Dispensing

When considering media dispensing for the microbiology lab, evaluate how automated equipment can positively impact:

• STERILITY: System maintains sterility;
• ACCURACY: Dispenses an accurate volume for plates, tubes and bottles;
• SIMPLICITY: System is easy to use and quick (walk-away system), provides a cooling device and plate printer;
• PRODUCTIVITY: Automatically produces a high number of plates and tubes in the shortest time possible; cooling system makes plates available quicker and prevents condensation so plate quality is high;
• VERSATILITY: Uses different brands of Petri dishes;
• STANDARDIZATION: Always dispenses the same way independent of the operator.

Case Study: Media Dispensing

As a result of public health emergencies like the Jack-in-the-Box E. coli outbreak in 1993 and the focus on homeland security resulting from 9/11, Mike McDowell, microbiologist IV and supervising microbiologist for the Washington State Department of Health, was able to get the support and funding to automate his laboratories.

During the Jack-in-the-Box outbreak, McDowell and his staff spent the better part of two weeks and many late nights manually pouring media so they had enough plates to test hundreds of specimens a day. Since 9/11, they have been doing a lot more testing for hospitals, local health departments, the U.S. Department of Justice, for mysterious white powders, botulism and unusual infections. Of course, this is in addition to their normal workload for their microbiology labs; virology, bacteriology, a special bacteriology lab for bioterrorism response, an enteric lab, group A strep, whooping cough (by the 100’s), etc.