carumonam and Escherichia-coli-Infections

The murine immune response to Escherichia coli exposed to subminimal inhibitory concentrations of four antibiotics was investigated. Groups of mice were injected for 8 weeks with formalin-killed bacteria and subsequently challenged with 10 x LD50 of viable E. coli. Mice receiving saline only (controls) died within 24 h. The mortality of mice immunized with ciprofloxacin-treated E. coli was significantly lower than that of mice immunized with E. coli untreated or treated with other antibiotics. Sera from mice immunized with ciprofloxacin-treated bacteria showed better bacteriostatic capacity and enhanced production of antibodies that bound to homologous and heterologous lipopolysaccharide isolated from several smooth and rough gram-negative strains. The better protection observed in mice immunized with ciprofloxacin-treated E. coli was probably due to an enhanced production of antibodies to epitopes on lipopolysaccharide that became better exposed and so more accessible after treatment with ciprofloxacin.

Topics: Animals; Anti-Bacterial Agents; Aztreonam; Blood Bactericidal Activity; Ceftriaxone; Ciprofloxacin; Complement System Proteins; Enzyme-Linked Immunosorbent Assay; Epitopes; Escherichia coli; Escherichia coli Infections; Female; Immunization; Immunoglobulin G; Immunoglobulin M; Lipopolysaccharides; Mice; Mice, Inbred BALB C; Netilmicin; Opsonin Proteins; Phagocytosis

The in vitro and in vivo activity of carumonam was tested in comparison with that of aztreonam and other beta-lactam antibiotics. With the exception of a few isolates that were overproducers of cephalosporinase, Enterobacteriaceae were highly susceptible to carumonam, 90% of the isolates being inhibited at 0.5 micrograms/ml. Aztreonam, ceftriaxone and ceftazidime were overall slightly less active than carumonam against Enterobacteriaceae. Carumonam was intermediate between ceftazidime and aztreonam as to the activity against Pseudomonas aeruginosa. Staphylococci were resistant to the monocyclic beta-lactams. In accordance with the in vitro data, carumonam was effective against experimental septicemias and infections of the thigh and the kidney that were caused by gram-negative pathogens.

Topics: Animals; Anti-Bacterial Agents; Aztreonam; Bacteria; Enterobacteriaceae; Escherichia coli Infections; Female; Hydrogen-Ion Concentration; Leukopenia; Mice; Mice, Inbred Strains; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Pyelonephritis; Rats; Rats, Inbred Strains; Sepsis