cylinders and two-liter glass flasks,
respectively, for use in isolators.
When it first opened, the facility
experienced several issues with
autoclave performance, including
failure of door gaskets and vacuum
pumps. These issues resulted in the
loss of numerous batches of supplies
due to excessive load condensate
or the inability to quickly remove
supplies from the autoclave post-cycle, as well as contamination of
several sterile isolators.
Eventually, the facility’s main
autoclaved was replaced with a new
Gnotobiotic animals are reared
in a sterile or microbially defined
environment, and they are only
exposed to those microorganisms that
the researchers wish to have present
in the animal.
Working with these animals requires
specialized care and operations. The
Gnotobiotics Core facility contains
100 flexible film isolators to house
laboratory mice and rats.
Isolators allow researchers to
house research animals in completely
defined conditions. Sterile
feed, water, bedding,
enrichment items and other
materials are entered into
the isolator via a port on one
side. Researchers are able
to access the animal through
a pair of gloves sealed to
the isolator for husbandry
This specialized housing
requires a greater time
investment by staff. While a
speedy staff member may
be able to quickly clean and
move laboratory animals to
new cages, changing the cages in an
isolator will take more time due to the
specialized care needed.
“Manipulations are definitely more
difficult, but much of the work in these
systems is also in sterilizing supplies
and performing the maneuvers to get
them into the isolator,” Swennes said.
“If you were to forget needed
supplies for an isolator and realize
this at the last minute, it would take
several days to pack, autoclave,
validate and enter those supplies.
It requires a lot of planning and
coordination. Also, there is risk of
contamination each time an isolator
is opened. We try to limit this. Busy
isolators are typically opened every
To prove that the animals used
in this kind of research contain only
known microbes, researchers at the
Gnotobiotics Core facility routine
collect samples from the isolators.
They then perform microscopic
examination, aerobic and anaerobic
bacterial culture, fungal culture and
16S rRNA qPCR with the goal of
detecting bacteria and fungi that
should be excluded.
The Gnotobiotics Core at
the Baylor College of Medicine
provides specialized handling and
care, ensuring that the animals
housed there contain only certain
microorganisms. Every aspect of the
facility, from design to operations,
reflects careful attention to detail.
To prepare for its use as a gnotobiotics facility,
a small animal holding room was converted
to a supply preparation space. Image:
A rack holding steel supply cylinders is used to autoclave food, bedding and other supplies. Once
autoclaved, these cylinders can connect to the port of an isolator using a sterilized nylon sleeve.
Image: Scott Bruss
“Working with these