[1] Univ Washington, Dept Pathobiol, Seattle, WA 98195 USA
[2] Pfizer Inc, Cent Res, Dept Infect Dis, Groton, CT 06340 USA
[3] Inst Pasteur, Unite Agents Antibacteriens, Paris 15, France
[4] Danish Vet Lab, DK-1790 Copenhagen, Denmark
[5] Monash Univ, Dept Microbiol, Clayton, Vic 3168, Australia
[6] Natl Publ Hlth Inst, Antimicrobial Res Lab, FIN-20520 Turku, Finland