Shipping germ-free or gnotobiotic animals is a challenge with many variables to control.  Currently the most common option for shipping these animals is the flexible film style shipper that will connect directly to the port of a flexible film isolator.  However these shippers can be expensive and limit the number of animals to 3 cages within the shipper.  Resterilising used shippers is also expensive and sometimes the ring inside the shipper can fail upon resterilisation due to the cardboard getting wet and losing rigidity.

Standard style gnotobiotic shipper connected to an isolator

Whilst there are existing smaller reusable options for shipping Gnotobiotic mice, these require return shipment the sending facility.  In Australia, due to the large geographical distances between facilities we needed a disposable option that was inexpensive.

Together with the Gnotobiotic Facilities at WEHI and SAHMRI in Australia, the TRI Gnotobiotic facility has refined the use of a disposable IVC cage to enable shipping germ-free mice between facilities in Australia.

The filter top of the cage is taped with vinyl tape across all seams between the filter and the plastic top.  It is then double sealed in polypropylene bags using a heat sealer, and gamma irradiated at 50kGy to sterilise.  The base of the cage can be cold sterilised prior to packing in a Biological Safety Cabinet (BSC).

The inside of the disposable filter lid is taped across all seams and then heat sealed into a polypropylene bag to send away for  irradiation.

When ready to ship, supplies are dunked into the BSC (disposable cage bases, bagged irradiated lids and vinyl tape, autoclaved packs of food and bedding, sterile gel packs).  After a UV cycle, germ-free or Gnotobiotic animals are transferred to the BSC from isolators in sealed sterile containers, and dunked into the cabinet.

Dunking the cage base in chlorine dioxide
Dunking the taped and irradiated filter lid in its bag
Inside the isolator mice are packed inside a plastic container, and then double contained in a ziplock bag.  These have previously been cold sterilised for entry into the isolator.

Utilising strict aseptic technique the animals are packed into the sterile cages, the lids are taped to the bases using irradiated tape.  Packed cages are then double contained in an autoclaved outer shipper and are ready for transport.

The mice are transferred into the sterilised shipper inside a biosafety cabinet and the lid is taped to the base.
The sterile cage is placed into an autoclaved outer shipper for transport.

The receiving facility will utilise glue backed plastic to tape over the filter part of the lid, allowing the cage to be fully dunked into a BSC.  Animals are carefully transferred into sterile positive pressure Gnotobiotic cages, or can be transferred into isolators.

The filter is taped over, then the sterile cage is dunked in sterilant.
The dunked cage is opened inside a BSC for transfer to isolators/isocages

It is worth noting that the success of this method does rest on excellent aseptic technique in the biosafety cabinet, and a relatively short shipment duration (< 48 hours).  For longer durations we would still recommend the standard flexible film shipper.  We have found this method to be a reliable and cost-effect solution to shipping within Australia.

Emily Duggan
Senior Gnotobiotic Facility CoordinatorTranslational Research Institute