Variability of immune response induced by bacteria treated with subminimal inhibitory concentrations of fosfomycin

Experiments were conducted to explore the possibility that bacterial strains treated with subminimal inhibitory concentrations (sub-MICs) of fosfomycin might induce immune responses different from those induced by intact, untreated bacteria. A preliminary study was done with a strain of Salmonella wien. The immune response in rabbits immunized with bacteria that had been exposed to either the sub-MIC or the minimal inhibitory concentration (MIC) of fosfomycin was compared with that in rabbits immunized with S. wien not exposed to the drug. The titers of antibody to S. wien in rabbits immunized with abnormal, sub-MIC-treated bacteria were higher than those in rabbits immunized with either MIC-treated or untreated S. wien. This difference was seen not only with the total antigen of Salmonella but also with somatic (O) and flagellar (H) antigens.