Metaphylactic Antibiotic Treatment to Prevent the Transmission of to Immunocompromised Mouse Offspring.

Current methods for eradicating , such as depopulation, embryo transfer, and cesarean rederivation followed by cross fostering, are expensive, complex, and time-consuming. We investigated a novel method to produce immunocompromised offspring free of from infected NOD. Cg-PrkdcIl2rg/SzJ (NSG) breeding pairs. Adult NSG mice were infected with , paired, and randomly assigned to either a no-antibiotic control group (NAB, = 8) or a group that received amoxicillin-clavulanic acid (0.375 mg/mL) in their drinking water for a mean duration of 7 wk (AB group, = 7), spanning the time from pairing of breeders to weaning of litters. The AB group also underwent weekly cage changes for 3 wk after pairing to decrease intracage contamination, whereas the NAB mice received bi-weekly cage changes. Antibiotics were withdrawn at the time of weaning. All litters ( = 7) in the AB group were culture- and qPCR-negative for and remained negative for the duration of the study, whereas all litters in the NAB group ( = 6) remained positive. A single adult from each breeding pair was sampled at weaning and at 5 and 10 wk after weaning to confirm the maintenance of (NAB) or to diagnose the reemergence (AB) of infection. By the end of the study, infection had returned in 3 of the 7 (43%) tested AB adults. Our data suggest that metaphylactic antibiotic use can decrease viable organisms from adult breeder mice and protect offspring from infection. However, using antibiotics with frequent cage changing negatively affected breeding performance. Nevertheless, this technique can be used to produce -free NSG offspring from infected adults and may be an option for salvaging infected immunocompromised strains of mice that are not easily replaced.