The
in vitro
antimicrobial susceptibility of Gram-negative anaerobic bacilli commonly isolated from footrot in goats was studied. A total of 97 isolates belonging to the genera
Dichelobacter, Fusobacterium, Prevotella, Porphyromonas
and
Bacteroides,
obtained from clinical cases of footrot in south-western Spain between March 2000 and May 2001, were tested against 25 antimicrobial agents comprising β-lactams, aminoglycosides, macrolides, chloramphenicol, quinolones, lincosamides, sulphonamides and tetracyclines in order to optimise antibiotic treatment of this disease in goats. β-lactams, tetracyclines and metronidazole displayed the highest
in vitro
efficacy against the species involved in the pathogenesis of footrot.