Cross-foster rederivation compared with antibiotic administration in the drinking water to eradicate bordetella pseudohinzii

Bordetella pseudohinzii is a microbial agent of potential importance in mice and has confounded pulmonary research at our institution. The purpose of this study was to evaluate cross-foster rederivation and antibiotic administration in the drinking water as methods to eradicate B. pseudohinzii. To evaluate the efficacy of cross-foster rederivation, 29 litters representing 16 strains of mice were cross-fostered from cages positive for B. pseudohinzii to B. pseudohinzii-negative Crl:CD1-Elite surrogate dams. To evaluate antibiotic administration, sulfamethoxazole and trimethoprim (TMS; 0.66 and 0.13 mg/mL, respectively) and tetracycline (4.5 mg/mL) were administered in the drinking water. We assessed 3 antibiotic treatment groups with 12 B. pseudohinzii-positive cages per group (6 cages of CD1 and 6 cages of C57BL/6 mice): TMS for 4 wk, TMS for 6 wk, and tetracycline for 6 wk. Of the 29 litters that underwent cross-foster rederivation, 24 were negative for B. pseudohinzii. Five of the 12 cages treated with TMS for 4 wk and 1 of the 12 cages treated with TMS for 6 wk were negative for B. pseudohinzii at 2 wk after treatment. Three of the 12 cages treated with tetracycline were negative for B. pseudohinzii at 2 wk after treatment. Pearson χ² analysis revealed significant association between the method of eradication (cross-foster rederivation compared with antibiotic administration) and B. pseudohinzii infection, and an odds-ratio estimate from a logistic regression demonstrated that cross-foster rederivation was more successful. Whereas antibiotic administration in the drinking water failed to eradicate B. pseudohinzii, cross-foster rederivation was successful and has been used to establish a B. pseudohinzii-negative barrier.