Evaluation of exhaust air dust polymerase chain reaction as a supplement method for soiled bedding sentinel monitoring in specific pathogen free mouse facility using two different individually ventilated cage racks

Health monitoring is essential for ensuring animal health and reliable research results. Each animal facility should establish adequate health monitoring methods, and microbiological quality control should be implemented through regular health surveillance. Recently, specific pathogen free (SPF) mice have been housed in individually ventilated cage (IVC) racks in the majority of mouse facilities globally, and health monitoring is implemented using a soiled bedding sentinel (SBS). Even though SBS monitoring is a standard method, it has a limitation in that some pathogens are not sufficiently transmitted to the sentinel housed in the IVC. The exhaust air dust polymerase chain reaction (EAD PCR) method has been reported to be a reliable complementary method to SBS monitoring based on research findings. In Korea, health monitoring programs using EAD PCR have not yet been applied to laboratory animal facilities. The microbiological status of mouse colonies housed in the two IVC racks was compared using SBS and EAD PCR monitoring in our SPF mouse facility. Except for Helicobacter spp. and Staphylococcus aureus, the detection of 16 pathogens did not differ between the two methods. In the detection of Helicobacter spp., EAD PCR was found to be more sensitive than SBS. Helicobacter spp. were not found by SBS, whereas four S. aureus positive samples were detected by either SBS or EAD PCR test. According to our findings, EAD PCR can be used as a supplement to SBS monitoring. Moreover, EAD PCR can reduce the number of animals used, making it a 3R (Replacement, Reduction, Refinement)-consistent method.N