G-CSF immunotherapy for treatment of acute disseminated murine melioidosis.

Burkholderia pseudomallei, the causative agent of melioidosis, is an important pathogen in tropical regions of Australia and Southeast Asia. Antibiotic therapy can be ineffective in patients with acute septicaemic melioidosis. It has been proposed that adjunctive immunotherapy using granulocyte colony stimulating factor (G-CSF) combined with antibiotics may provide an alternative approach to antibiotics alone. We have developed a murine model for melioidosis that allows novel treatment approaches to be investigated. This study looked at the potential for murine G-CSF therapy both alone and as an adjunct in the treatment of acute disseminated B. pseudomallei infection in BALB/c mice. A number of therapeutic variables involving ceftazidime and recombinant murine G-CSF were studied. Surviving mice were sacrificed and splenic bacterial loads were determined. Combining recombinant murine G-CSF with ceftazidime offered no advantage over ceftazidime alone. Pre-treatment with recombinant murine G-CSF did not demonstrate a significant benefit. This would suggest that adjunct immunotherapy using G-CSF is of limited benefit.