Clinical characteristics of bacteremia caused by Helicobacter cinaedi and time required for blood cultures to become positive.

The aim of this study was to clarify the clinical characteristics of patients with Helicobacter cinaedi bacteremia and the time required for blood cultures to become positive. The medical records of all patients with H. cinaedi bacteremia at Toranomon Hospital and Toranomon Hospital Kajigaya between March 2009 and March 2013 were retrospectively reviewed. Sixty-three patients, 34 men and 29 women with a median age of 67 years (range, 37 to 88 years), were diagnosed with H. cinaedi bacteremia. A total of 51,272 sets of blood cultures were obtained during the study period, of which 5,769 sets of blood cultures were positive for some organism and 126 sets were H. cinaedi positive. The time required for blood cultures to become positive for H. cinaedi was ≤5 days in 69 sets (55%) and >5 days in 57 sets (45%). Most patients had an underlying disease, including chronic kidney disease (21 cases), solid tumor (19 cases), hematological malignancy (13 cases), diabetes mellitus (8 cases), chronic liver disease (6 cases), and postorthopedic surgery (3 cases). Only 1 patient had no apparent underlying disease. The clinical symptoms included cellulitis in 24 cases, colitis in 7 cases, and fever only in 27 cases, including 7 cases of febrile neutropenia. The 30-day mortality rate of H. cinaedi bacteremia was 6.3%. In conclusion, most cases of H. cinaedi bacteremia occurred in immunocompromised patients. We might have overlooked nearly half of the H. cinaedi bacteremia cases if the duration of monitored blood culture samples had been within 5 days. Therefore, when clinicians suspect H. cinaedi bacteremia, the observation period for blood cultures should be extended.