The MICs of pipemidic acid (PPA) were 100 μg/ml or more against most anaerobic bacteria, but were 50 μg/ml against C. perfringens. Strains of P. acnes stocked in our laboratory showed 100 μg/ml or more, but those isolated from clinical materials showed 25 pg/ml to 50 μg/ml in 8 of 11strains.
Antimicrobial activity of PPA against anaerobic bacteria was a little better than that of PA in gram-positive cocci, but was similar to that of PA in gram-negative rods and positive rods. It seemed that PPA was generally better than NA in antimicrobial activity against anaerobic bacteria.
