EXPERIMENTAL MELIOIDOSIS IN INBRED MOUSE STRAINS

Exerimental infection was induced in three inbred mouse strains (BALB/ c, BDF1 hybrid and C57BL) by i.p. inoculation with Pseudomonas pseudom allei. The bacterial load in the viscera and the host response induced in different compartments (blood, peritoneal cavity and organs) were determined. Blood cell parameters and peritoneal exudative cell popula tions were evaluated during the infection with the aid of an automated haematology analyser Technicon H-1. It was found that all mouse strai ns produced a similar intraperitoneal inflammatory response with predo minance of granulocytes at the early stage of infection and subsequent increase of macrophages especially in BDF1 hybrid and BALB/c mice. Th e highest bacterial count found in the liver and spleen of C57BL was a ssociated with corresponding tissue damage (purulent pneumonia, absces ses in liver, karyorrhexis of hepatocytes and meningoencephalitis). Th e degree of bacterial load and histological changes found in BALB/c an d BDF1 hybrid mice were lower than in C57BL mice. The results show tha t the variations in the infection magnitude among inbred mouse strains are host-dependent.