The bactericidal activity and postantibiotic effect of trospectomycin.

Trospectomycin sulfate (trospectomycin, TRS) is a novel, broad-spectrum, aminocyclitol antibiotic that is being developed clinically for the treatment of upper respiratory tract infections, bacterial vaginosis, pelvic inflammatory disease, and gonorrhea. This study investigated the bactericidal activity (by time-kill kinetics) and the postantibiotic effect (PAE) of TRS. Species-dependent bacteriostatic/bactericidal activity was observed for TRS; the antibiotic was bacteriostatic for Staphylococcus epidermidis, Enterococcus faecalis, and Escherichia coli, and bactericidal for Haemophilus influenzae, Neisseria gonorrhoeae, Moraxella catarrhalis, and Bacteroides fragilis (one of two test strains). When TRS was tested at four times its minimum inhibitory concentration or at a maximum test concentration of 32 micrograms/ml, with a 1-hr exposure period, the following PAE values were recorded: S. epidermidis 30032, 1.8 hr, En. faecalis ATCC 29212, 1.6 hr, E. coli UC 311, 1.5 hr, E. coli UC 9451, 1.5 hr, H. influenzae 30063, greater than 4.0 hr, B. fragilis ATCC 25285, 5.2 hr, and B. fragilis UC 12199, 6.7 hr. The broad-spectrum PAE that was observed for TRS is somewhat unique compared with other antibiotics.