Maintaining and Monitoring the Defined Microbiota Status of Gnotobiotic Rodents

Gnotobiotic (germfree, defined colonized) rodents have become powerful tools to advance our understanding of the host-microbiome relationship. However, the maintenance and ultimately the monitoring of gnotobiotic rodents is a critical, labor-intensive, and costly process (e.g., sterility, not absence of specific pathogens, must be demonstrated in germfree animals). Here, we provide information on the housing and maintenance of gnotobiotic animals, elucidate prophylactic measurements to avoid contamination, and make specific recommendations for sampling procedures, sampling frequencies, and test methods.