by A.B. Ebeling
Cross contamination can pose problems across many different laboratory settings. Avoiding cross contamination when performing any kind of biological research, especially in a vivarium or animal research facility, is of paramount importance to protect the integrity of research results and pharmaceutical products alike. Protecting laboratory personnel and ensuring their health and safety is equally critical in any lab operation.
Options exist on multiple levels to address these concerns and offer choices to limit the chances of cross contamination in a vivarium setting. These range from how you set up your lab to how you set up your experiment, as well as choosing to invest in the right equipment for your specific research needs. Implementing strategies to avoid cross contamination helps to protect lab workers from occupational hazards and could end up saving both time and resources by preserving the accuracy of research data.
Lab managers and, in fact, the entire team need to be aware of specific considerations when working in an animal research facility and must understand best practices of how to avoid cross contamination. The first step is the design of the animal facility itself. Animal facilities are often set apart from other areas of a research institution in a limited access environment. The purpose of this is to safely and securely house the animals there, but also to restrict access by other research teams as multiple groups from various areas of a research facility sharing the same equipment poses a serious cross-contamination risk.
Vivaria also have stricter heating, ventilation and air-conditioning (HVAC) considerations as well as higher air quality standards than other spaces in a research facility, and may have entirely separate HVAC and mechanical systems altogether. Animal facilities often utilize high energy particulate air (HEPA) filters in their HVAC design, with the goal of eliminating contaminated air recirculating either within the animal facility or to other areas in the building. While these needs can be a lot to handle when designing the space initially, they make all the difference in ensuring the vivarium is a safe, contained and isolated space where transfer of air, particulates, pathogens and research agents are strictly controlled.
Tip No. 1: Optimize Cage Changing Procedures
When cage changing small animals in a vivarium setting, a changing station works to ensure both laboratory personnel and the research animal are being protected. An animal transfer station (ATS) is a popular option in vivaria for performing cage changing procedures because it is an ergonomic and easy to use unit with a number of features that optimize workflow and ease of use, depending on a lab’s specific needs. An ATS is usually a mobile unit, which provides for easy transport throughout the vivarium, with models offered either with single-sided access or dual-sided openings. Having an ATS with access on both sides allows for multiple lab members to more easily share the same workspace and maximizes flexibility with regards to ergonomic and workflow options.
Meanwhile, an animal transfer station with single side access offers a higher level of personnel, product and environmental protection during cage changing procedures than a unit with dual-sided access. Room air is drawn through the supply pre-filter located on top of the station and passes through a HEPA filter, which filters 99.99% of particulates 0.3 microns in size.
This contaminant-free air moves uniformly over the work surface, maintaining sterility of the work zone inside the ATS. The “dirty” air from the work surface moves through a grille of perforated vacuum slots around the perimeter of the unit. It then passes through an exhaust HEPA filter, minimizing the amount of allergens and irritants created from animal dander, hair or waste produced during the cage change being dispersed back into the laboratory. The laminar air flow pattern provides an active air barrier of 75 fpm (0.38 m/s) at the front of the unit that separates the user from the work zone inside the unit.
Tip No. 2: Customize Your Lab’s Animal Transfer Station
An animal transfer station with a variety of customization options offers choices with the ability to improve ergonomics and workflow when cage changing small animals. When performing multiple cage changes or working for an extended period of time in uncomfortable positions, lab personnel may become prone to mistakes, which can easily lead to contamination issues. Having a large, clear workspace with easy access and an ergonomic setup are key in optimizing workflow and lowering the risk of cross contamination.
When cage changing a small animal, there should be enough room to accommodate separate spaces for clean and dirty cages, as well as clean and dirty instruments and supplies. Manufacturers offer a variety of options to provide accessibility and improve ergonomics for the user, including different widths to allow lab managers to choose the right size for their facility.
A large surface area of the work environment, along with add-on options such as a folding shelf or embedded base stand shelf for storage, create options for optimizing workspace and by extension, workflow. Additionally, a cage top holder, bottle rack stand or hand sanitizer dispenser built into the unit, can help reduce the risk of cross contamination. Knowing the needs of your research and choosing the appropriate configuration and options that laboratory equipment manufacturers offer will strengthen protection for the laboratory worker, the research animal, and the work surface inside the unit.
Just as the overall design of a vivarium is important, where the ATS is placed within a laboratory is also a factor in mitigating cross contamination. Avoid placing the changing station near a door or other high traffic area as this can disrupt the laminar airflow and compromise the air barrier of the unit. Only perform procedures in the ATS when the sash is open to the designated height. In addition, do not use the changing station to store any unrelated instruments or equipment while performing manipulations on small animals, and do not leave anything inside the ATS when it is not in use. Take care not to block the pre-exhaust mesh with any equipment, as this can disrupt the equilibrium of the airflow.
Tip No. 3: Ensure Proper Protection for Personnel and Product
While an animal transfer station utilizing HEPA-filtered air and laminar airflow provide a high degree of protections for both personnel and product, depending on your specific research needs, hazardous and infectious agents designated at biosafety level 2 or higher may have to be used during the course of your work. If this is the case, an ATS will not be sufficient and a biological safety cabinet (BSC) should be utilized.
When beginning a small animal cage change, always use the appropriate level of personal protective equipment (PPE) required for the task. First, turn on the ATS and allow the blower to operate for the amount of time recommended by the manufacturer to allow the airflow to normalize. Use a chemical disinfectant to clean and sanitize the interior of the transfer station before commencing work. While performing manipulations inside the ATS, movement in and out of the work area and other activity taking place within the room should be kept to a minimum to avoid altering the airflow throughout the facility and within the changing station. Lab personnel should avoid rapid movements or activities like vigorously dumping bedding, which can create splashes and aerosolize particulates and microorganisms, creating a greater risk of cross contamination and exposing the lab worker to potentially harmful irritants. Once the procedure is finished, decontaminate the workspace again and discard all waste properly. Some ATS’s even include a built-in waste chute to conveniently dispose of waste produced during a cage changing procedure.
A lab team with a strong commitment to avoiding cross contamination is just as critical to the success of a lab as any equipment used. Consistently using best practices ensures that cage changes are performed safely and that the benefits of an ATS are properly utilized. In a vivarium, developing and following a clearly defined standard operating procedure (SOP) for small animal cage changing procedures is vital to using an ATS in a way that maximizes environmental, personnel and research product protection.
About the author
A.B. Ebeling is a freelance science writer with has a Bachelor’s degree in cell biology and neuroscience from Rutgers, the State University of New Jersey. He has completed graduate level coursework in molecular and cell biology, anatomy, physiology, pathology, immunology and infectious diseases. With research positions held at The W.M. Keck Center for Collaborative Neuroscience, the University of Pennsylvania School of Medicine, and Sidney Kimmel Medical College, he has training in general research principles and practices, scientific protocols and research techniques across multiple settings