BACTERICIDAL ACTIVITY OF 6 ANTIBIOTICS AND 3 ASSOCIATIONS ON 6 STRAINS OF SALMONELLA ISOLATED FROM BLOOD

The bactericidal activity of 6 antibiotics and 3 combinations was eval uated against 6 Salmonella strains isolated from blood: 3 sensitive to all antibiotics tested(1 Salmonella Typhi, 1 Salmonella Paratyphi A e t 1 Salmonella Enteritidis) and 3 harbouring a TEM penicillinase (1 Sa lmonella Typhi, 1 Salmonella Virchow et 1 Salmonella Typhimurium). MIC s of 6 antibiotics, ceftriaxone, cefotaxime, cefoperazone, ciprofloxac in, amikacin and chloramphenicol were determined by microdilution meth od in Mueller Hinton broth. The bactericidal activity of these antibio tics and 3 combinations (ciprocloxacin + ceftriaxone, ciprofloxacin amikacin and ceftriaxone + amikacin) was determined by the killing cur ve method with 10(6) cfu/ml inocula and 4 x MIC for antibiotics concen trations. Chloramphenicol, only tested on typho-paratyphi strains, had only a bacteriostatic effect at 24 hours. Amikacin and ciprofloxacin had a faster and better bactericidal activity than cephalosporins. Com binations were either additive or synergistic. Those including amikaci n had the best results, but any can be proposed for initial treatment of severe Salmonella infections in immunosuppressed patients.