[A Case of Brucellosis with Intermittent Fever in a Patient Returning from France]

We herein report on a 62-year-old man who presented with symptoms of intermittent fever that persisted after returning from a trip to France. During his trip, he had eaten natural cheese. Although no bacteria could be isolated from blood culture, the serum agglutination test showed a positive antibody titer of 1 : 160 for Brucella canis. The patient responded well to combination antibiotic therapy consisting of gentamicin, rifampicin, and doxycycline, and his symptoms improved. He became antibody-negative after antibiotic therapy. Although the present case may have been a case of B. canis infection, considering the epidemiology of brucellosis in France, serological cross-reactivity with Brucella melitensis infection is also a possibility. Concerns regarding the reemergence of brucellosis have recently been reported in France, and most cases are caused by B. melitensis. Clinicians should be aware of the fact that blood cultures must be incubated for ≥ 21 days for isolation of Brucella and that in Japan, antibody measurement of B. melitensis cannot be performed on a commercial basis.