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COMPARISON OF THE ACTIVITY OF MEROPENEM AND IMIPENEM AGAINST ANAEROBIC BACTERIA IN BULGARIA

Marina M.¹*, Ivanova K.¹, Urumov A.^{2 1} National Center of Infectious and Parasitic Diseases, ² National Drug Institute, Sofia, Bulgaria

The in vitro activities of meropenem and imipenem were compared against 154 clinical isolates of anaerobic bacteria representing 23 species of 10 genera using the NCCLS - recommended agar dilution method of Wadsworth Anaerobic Laboratory with Brucella agar.

Meropenem proved to be more active than imipenem with a MIC range <= 0,125 - 4 µg/ml, MIC₅₀-0,25 µg/ml, MIC₉₀ -1 µg/ml and 100% of the strains susceptible at the breakpoint - 4 µg/ml /according NCCLS/.

Imipenem showed a lover activity and MIC range <= 0,125 - 16 µg/ml, MIC₅₀ -2µ/ml and MIC₉₀ - 4 µg/ml with 10% of the strains not inhibited at this concentration. 96% were susceptible at 8 µg/ml and 100% - at 16 µg/ml.

The MIC for both antibiotics /especially for imipenem/ were higher in the B.fragilis group than in the rest of the Gram-negative and even more - in the Gram-positive anaerobes.