ENHANCEMENT OF THE SUSCEPTIBILITY OF STAPHYLOCOCCUS-AUREUS TO PHAGOCYTOSIS AFTER TREATMENT WITH FOSFOMYCIN COMPARED WITH OTHER ANTIMICROBIAL AGENTS

Phagocytosis and intracellular killing of invading pathogens by host c ells play the major role in resistance to bacterial infections. In vit ro, antibiotics improve the susceptibility of microorganisms to antimi crobial activity of leukocytes, suggesting that this effect may contri bute to determine the antimicrobial therapy and safe dosing intervals. The susceptibility of Staphylococcus aureus to phagocytosis and killi ng by human polymorphonuclear leukocytes (PMNL) in the presence of nor mal human serum the postantibiotic phase of fosfomycin were compared w ith ciprofloxacin, cefotaxime and pristinamycin. Pretreatment of S. au reus for 10 min with 4 x MIC of fosfomycin and ciprofloxacin clearly s ensitized the bacteria to leukocytic killing in the presence of normal human serum (10% v/v); cefotaxime and pristinamycin failed to enhance the phagocytic killing.