Serologic Study of Bartonella henselae in Patients with Acute Undifferentiated Febrile Illness in Korea.

BACKGROUND: Bartonella infection is an emerging cause of acute febrile illness; however, its significance has not been thoroughly investigated. We studied the antibody specific to Bartonella henselae in patients with various febrile diseases in Korea. MATERIALS AND METHODS: A total of 177 patients with acute febrile illness who were managed at the Inha University Hospital from February 2012 to January 2013 were evaluated with an in-house immunofluorescent antibody test to detect B. henselae immunoglobulin G (IgG) antibody. The clinical features of the patients included fever of undetermined origin (n = 88 patients), lymphadenopathy (n = 28), febrile rash (n = 17), respiratory infection (n = 12), aseptic meningitis (n = 7), intra-abdominal infection (n = 5), arthritis (n = 4), and other conditions (n = 16). We reviewed the medical records of these patients and collected demographic data, clinical features, and their histories of animal exposure. RESULTS: Among the 177 patients with acute febrile illness, 23.7% (42/177) had elevated levels of IgG antibodies to B. henselae (≥1:160). Of these seropositive patients, 32.4% (12/37) had contact with animals and had developed arthralgia (29.5%), headache (25%), or lymphadenopathy (15.9%). Seven (16.7%) of the 42 patients had higher IgG titers (≥1:640). Among them, four patients presented fourfold increase/decrease of IgG in convalescent serum. According to the clinical diagnosis, the antibody positivity rates were as follows: 24/88 with undifferentiated fever, 8/28 with lymphadenopathy, 4/17 with febrile rash, 2/12 with respiratory infection, 2/7 with aseptic meningitis, and 2/16 with other illnesses. CONCLUSIONS: There was high prevalence of B. henselae in patients with undifferentiated fever in Korea, for which further research is needed.

In Vitro Activity of Tigecycline Against Orientia tsutsugamushi.

Scrub typhus is a zoonosis caused by Orientia tsutsugamushi (O. tsutsugamushi) occurring mainly in autumn in Korea. The need of new antibiotics has arisen with a report on strains resistant to antibiotics and chronic infection. This study aims to identify susceptibility of tigecycline in-vitro as a new therapeutic option for O. tsutsugamushi. Antibacterial activity of tigecycline against the O. tsutsugamushi was compared with doxycycline using flow cytometry assay. The inhibitory concentration 50 (IC50) was 3.59×10⁻³ µg/mL in doxycycline-treated group. Whereas in 0.71×10⁻³ µg/mL tigecycline-treated group. These findings indicate that tigecycline may be a therapeutic option for the treatment of scrub typhus.