Abstract
On 18 May 2002, a blood culture gave a positive signal after 48 h incubation on the BACTEC 9240 system. A slowly growing, oxidase-positive, Gram-negative bacillus failed to grow on MacConkey agar and was identified as O. anthropi in the API 20NE system, profile 1207004. This was thought to be of uncertain clinical relevance. However, because the patient was being investigated for possible endocarditis, repeat blood cultures were advised to help to assess significance. A further set of blood cultures sent on 23 May 2002 flagged positive after 48 h incubation. Gram-negative bacilli that failed to grow on MacConkey agar were isolated and identified as O. anthropi in the API 20NE system, profile 1201724. Further clinical history revealed that the patient's son, who had accompanied him on a trip to Cyprus, had been admitted to another hospital suffering from brucellosis. Subsequently, the patient's serum was tested for the presence of Brucella antibody. This test was positive and the reference laboratory confirmed acute Brucella infection by Brucella microagglutination test, complement fixation test, ELISA IgG and IgM. All blood culture isolates sent to a reference laboratory (Veterinary Laboratories Agency, Weybridge, Surrey, UK) were identified as Brucella melitensis (Table 1). The patient was treated for Brucella endocarditis with doxycycline and streptomycin.