Sterility testing of germ-free mouse colonies

In biomedical research, germ-free and gnotobiotic mouse models enable the mechanistic investigation of microbiota-host interactions and their role on (patho)physiology. Throughout any gnotobiotic experiment, standardized and periodic microbiological testing of defined gnotobiotic housing conditions is a key requirement. Here, we review basic principles of germ-free isolator technology, the suitability of various sterilization methods, and the use of sterility testing methods to monitor germ-free mouse colonies. We also discuss their effectiveness and limitations, and share the experience with protocols used in our facility. In addition, possible sources of isolator contamination are discussed and an overview of reported contaminants is provided.

[Development of an Isolator System for PET Drug Compounding with Sterilization and Dispensing Units]

To maintain sterility of PET drug is the most important for in-house positron emission tomography (PET) drug manufacturing, and sanitary control of the laboratory to perform aseptic procedure is the key point for the sterility of PET drugs. However, rigorous sanitary control affects both the high cost and the low efficiency. To conquer those, we developed an isolator system especially for PET drug compounding including sterilization and dispensing units. This system consists of a HEPA unit for inlet and outlet, positive regulation of the ear inside isolator, a sterilizer with vapored hydrogen peroxide and a dispenser with self-shield for radiation. We set the materials for the dispenser through gloves, and the compounding such as sterilization and dispensing PET drugs to the containers is performed automatically without radiation. High level assurance of PET drug sterility is expected to be accomplished in the PET centers of the hospitals without high level sanitary control.

Potential for using a hermetically-sealed, positive-pressured isocage system for studies involving germ-free mice outside a flexible-film isolator

Germ-free mice are used to examine questions about the role of the gut microbiota in development of diseases. Generally these animals are maintained in semi-rigid or flexible-film isolators to ensure their continued sterility or, if colonized with specific microbiota, to ensure that no new species are introduced. Here, we describe the use of a caging system in which individual cages are hermetically sealed and have their own filtered positive airflow. This isopositive caging system requires less space and reduces animal housing costs. By using strict sterile techniques, we kept mice germ-free in this caging system for 12 weeks. We also used this caging system and approach to conduct studies evaluating a) the stability of the microbiome in germ-free mice receiving a fecal transplant and b) the stability of dietary-induced microbiota changes in fecal-transplanted mice. As has been shown in fecal transfer studies in isolators, we found that the transferred microbiota stabilizes as early as 2 weeks post transfer although recipient microbiota did not completely recapitulate those of the donors. Interestingly, we also noted some sex effects in these studies indicating that the sex of recipients or donors may play a role in colonization of microbiota. However, a larger study will be needed to determine what role, if any, sex plays in colonization of microbiota. Based on our studies, an isopositive caging system may be utilized to test multiple donor samples for their effects on phenotypes of mice in both normal and disease states even with limited available space for housing.

To create a cleanroom controlled environment using a mobile air decontamination unit for the preparation of antineoplastic drugs

OBJECTIVES

To use a mobile air decontamination unit (MADU) for a microbial destruction and decreased particle burden making a cleanroom controlled environment in a Centralized Chemotherapy Preparation Unit (CCPU). Good manufacturing practices (GMP) in France specify that the ambient air in the vicinity of a class III biosafety cabinet (isolator) complies with air cleanliness ISO 8 level in CCPU. This guideline has a significant impact because implementing a dedicated air handling unit (AHU) brings some engineering constraints and generates substantial additional costs.

METHODS

Authors have previously studied some technical and economical aspects to evaluate the feasibility of the MADU option.

RESULTS

Using a MADU was the chosen option. Qualification of the CCPU showed that results were in compliance with the French GMP. After one year of use, the efficiency of the MADU was confirmed. According to these results, using a MADU constitutes a beneficial option for CCPU previously equipped with an isolator when compared to renovation work involving a standard built-in AHU.