Moving from guideline recommendations to practical, reasonable proposals: Biosafety considerations, breeding...

Extending an existing animal facility is a challenging process that requires consideration of both engineering and biological aspects. In this sense, integration with ongoing activities must not alter the animals' microbiological condition or welfare, as they usually remain in the facility while these activities occur. The objective of this work was to describe and evaluate the practical biosafety considerations during the enlargement of a specific pathogen-free (SPF) rodent facility. Our facility breeds rats and mice free of a list of zoonotic and common rodent pathogens, comprising 6 ectoparasites, 13 endoparasites, 25 bacteria and 23 viruses. In this project, the new SPF area was connected to an old but still working SPF rodent facility through the original clean corridor. The old clean corridor remained sealed throughout the project, and it was not opened until the new area was finished and fully equipped, all the new rooms were cleaned and disinfected, and the environment was evaluated for the presence of pathogens. Timing during the project was essential, as avoidance of the period of high animal production and demand was sought. The microbiological controls showed no growth of microorganisms in any new room. Thus, the applied procedures were deemed effective. It was concluded that protocols should be carefully planned in order to maintain the SPF condition and animal welfare.