In Vitro Activity of 39 Antimicrobial Agents Against Treponema hyodysenteriae

Abstract

The in vitro activities of 39 antimicrobial agents against 23 isolates of Treponema hyodysenteriae , the majority of which were field isolates, were determined by the agar dilution technique. Quinoxalines, pleuromutilin, nitroimidazoles, and nitrofuran were the most active. Their activities ranged from ≤0.10 to 1.56 μg/ml. Lincomycin, penicillins, chloramphenicol, tetracyclines, cephalosporins, three peptides (virginiamycin, thiopeptin, and bacitracin), and one aminoglycoside (gentamicin) exhibited intermediate levels of activity ranging from 0.39 to 50 μg/ml. Four peptides (enduracidin, viomycin, bicyclomycin, and colistin), three aminoglycosides (kanamycin, streptomycin, and neomycin), polyene, and other agents, including novobiocin, vancomycin, rifampin, nalidixic acid, and p -arsanilic acid, displayed limited activities ranging from 12.5 to ≥100 μg/ml. Macrolides showed varying degrees of activity depending upon isolates.