First case report of bacteremia caused by <i>Haematobacter massiliensis</i> in Turkey

Abstract Background Haematobacter massiliensis is a Gram-negative, non-motile, non-spore-forming, non-fermenting, pleomorphic, and aerobic bacillus. It is rarely isolated from bloodstream infections such as bacteremia, particularly in immunosuppressed patients. Case presentation We report the case of a 67-year-old female patient with a recent history of coronary angiography who presented to the Infectious Diseases outpatient clinic in February 2023 with complaints of fever, chills, rigors, and sweating. Blood cultures obtained for fever etiology identified Haematobacter massiliensis as the causative agent using MALDI-TOF MS and 16S rRNA gene sequencing. The patient was successfully treated and discharged in good health. Conclusions The paper reports the first case of bacteremia caused by Haematobacter massiliensis in Turkey. Haematobacter species are clinically significant due to their potential to cause bloodstream infections, particularly in immunosuppressed patients, and should be considered in the differential diagnosis. In patients presenting with fever of unknown origin, bacteremia, particularly when atypical growth patterns are observed in cultures, Haematobacter massiliensis should be considered a rare but potential pathogen.