Mouse model of sublethal and lethal intraperitoneal glanders (Burkholderiamallei)

Sixty male BALB/c mice were inoculated intraperitoneally with either a subl ethal or a lethal dose of Burkholderia mallei China 7 strain, then killed a t multiple time points postinoculation. Histopathologic changes were qualit atively similar in both groups and consisted of pyogranulomatous inflammati on. In sublethal study mice, changes were first seen at 6 hours in mediasti nal lymph nodes, then in spleen, liver, peripheral lymph nodes, and bone ma rrow at day 3. These changes generally reached maximal incidence and severi ty by day 4 but decreased by comparison in all tissues except the liver. Ch anges were first seen in lethal study mice also at 6 hours in mediastinal l ymph nodes and in spleens. At day 1, changes were present in liver, periphe ral lymph nodes, and bone marrow. The incidence and severity of these chang es were maximal at day 2. In contrast to sublethal study mice, the incidenc e and severity of the changes did not decrease through the remainder of the study. The most significant difference between the two groups was the rapi d involvement of the spleen in the lethal study mice. Changes indicative of impaired vascular perfusion were more frequently seen in the sublethal stu dy mice. Our findings indicate that mice are susceptible to B. mallei infec tion and may serve as an appropriate model for glanders infection in a resi stant host such as human beings. Additionally, by immunoelectron microscopy , we showed the presence of type I O-antigenic polysaccharide (capsular) an tigen surrounding B. mallei.