engleski

Antimicrobial susceptibility and in vitro postantibiotic effect of vancomycin and ciprofloxacin against Bacillus cereus isolates

Vancomycin nad ciprofloxacin were often used in therapy of infections associated with B. cereus. Four B. cereus food and clinical isolates were chosen for determination of time– kill curves and postantibiotic effect (PAE) of ciprofloxacin and vancomycin. According the MIC breakpoints defined by CLSI for Staphylococcus spp. were all four strains intermediate for vancomycin (MIC = 4 µg/ml) and sensitive to ciprofloxacin (MIC = 0.2 µg/ml) except the strain Bc63 resistant to the last antimicrobial (MIC = 1.6 µg/ml). The lowest CFU values of tested strains were reached after 3 to 5 h of exposure to 4×MIC of vancomycin, and after 6 to 7 h exposure to 10×MIC of ciprofloxacin. The maximum reduction of the CFU in the presence of vancomycin and ciprofloxacin was about 2∙46 log10 and 2∙48 log10, respectively. The average duration of the PAE of vancomycin and ciprofloxacin was 0∙94 h and 1∙60 h, respectively. The statistically significant differences between PAEs induced with 3×MIC, 4×MIC and 8×MIC of vancomycin ere observed (P<0∙05). Both antibiotics did not affect the sporulation of tested bacterial strains. The differences in PAE duration were strain and antimicrobial dependent.

Bacillus cereus ; Antibiotic susceptibility ; Postantibiotic effect ; Time–kill effect ; Sporulation.

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