Tularemia, an infection caused by the coccobacillus Francisella tulare
nsis, can be a difficult disease process to diagnose and treat. The di
fficulty in treating this disease is related to the pathophysiology of
the infection and the toxicity of the antimicrobial agents presently
recommended for treatment. Recent in vitro data have suggested that an
timicrobial drugs other than standard agents (streptomycin, gentamicin
, chloramphenicol, or tetracycline) may be effective. We present eight
cases of documented failure of outpatient use of ceftriaxone in the t
reatment of tularemia. Our data suggest that while ceftriaxone may hav
e excellent MICs in vitro, these MICs do not necessarily correlate wit
h successful in vivo outcomes.