Forty-two recent (1997-1999) Spanish isolates of Francisella tularensis subsp. holarctica were tested in a broth microdilution method for their susceptibilities to 29 antimicrobial agents, including penicillins, cephalosporins, cephamicins, monobactams, penems, aminoglycosides, tetracyclines, macrolides, quinolones, chloramphenicol and fosfomycin. The isolates were resistant to beta- lactam antibiotics and susceptible to chloramphenicol, ciprofloxacin, levofloxacin and norfloxacin. (C) 2004 Elsevier Ltd. All rights reserved.