1999 Volume 62 Issue 4 Pages 221-230
I studied β-lactamase, outer membrane permeability (OMP), and efflux of drugs to elucidate the role of the β-lactam antibiotic resistance of Prevotella intermedia MA 1-V2. β-Lactamase activity in the periplasmic space was 57〜88% inhibited by 0.25〜8μg / ml of 3 β-lactamase inhibitors. The inhibitors and β-lactams were added to cultures and the treatment continued for 0.5 hours. The β-lactamase antivity was inhibited 80〜96%. The inhibitors (clavu-lanic acid and tazobactam : 0.5μg / ml, sulbactam : 1μg / ml) and β-lactams (piperacillin and cefteram : 128μg / ml, cefazolin : 64μg / ml) were added to the cultures 3 hours after inoculation, decreasing the viable count. The MIC of 3 the β-lactams with inhibitors was decreased 1 / 512〜1 / 16. I also studied the effect of OMP on the MIC of β-lactams with ethylenediamine tetraacetic acid disodium salt, and measured the viable count with cyanide m-chlorophenylhydrazone to study drug efflux. No decrease was detected in either the MIC or viable count. These results suggest that lactamase activity in the periplasmic space was inhibited, causing a decrease in the viable count and MIC. This implies that β-lactamases are the most important factor in the β-lactam resistance of this strain.
