SYNERGY OF SIMULTANEOUS ADMINISTRATION OF OFLOXACIN AND GRANULOCYTE-COLONY-STIMULATING FACTOR IN KILLING OF ESCHERICHIA-COLI BY HUMAN NEUTROPHILS

The in vitro effect of subinhibitory and inhibitory concentrations of ofloxacin and G-CSF on the bactericidal activity of polymorphonuclear leucocytes (PMNL) against Escherichia coil was investigated, PMNL obta ined from healthy volunteers were incubated with different concentrati ons of G-CSF and ofloxacin for 180 min. The minimum inhibitory concent ration (MIG) of ofloxacin and even 1/4 x MIC enhanced the bactericidal activity of PMNL. G-CSF at a concentration of 6,000 units/ml led to a significant improvement of the bactericidal activity of PMNL. The com bination of 6,000 units/ml of G-CSF and ofloxacin in inhibitory as wel l as subinhibitory concentrations, however, showed a significant syner gistic effect on the antibacterial activity of PMNL during the complet e incubation period. Combinations of G-CSF and antibiotics could there fore be beneficial for infected patients, especially those with impair ed cellular host defense.