274. Diagnostic usefulness of a new in situ hybridization method for detection of global bacterial DNA in febrile neutropenia
Session: Poster Abstract Session: Diagnostic Microbiology; Novel Molecular Methods
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
Background: Identification of pathogens that cause febrile neutropenia (FN) remains extremely difficult, as the diagnostic performance of blood cultures is very poor. Enomoto et al. reported that a new in situ hybridization (ISH) method that detects global bacterial DNA in leukocytes may uncover bacterial infection in spontaneous bacterial peritonitis ascites (J Hepatol. 2012;56:85-94). The utility of this method in FN is however unknown.

Methods: We prospectively evaluated the utility of the ISH method in patients with hematological disorders who developed FN during chemotherapy between March 2012 and April 2013. Neutropenia was defined as a neutrophil count of less than 500/μl or less than 1,000/μl with an expected decline to less than 500/μl. Fever was defined as an axillary temperature ≥ 37.5 C based on a single measurement. Blood samples for cultures and the ISH test were collected simultaneously, at the onset of fever. Serum concentrations of procalcitonin (PCT) were also measured, with the cut-off value set at 0.5 ng/ml. In addition, we performed the ISH test at the time of neutrophil recovery and completion of antibiotics. Where the last follow-up test remained a positive result, an additional ISH test was performed. Patients with FN were classified into three groups: local infection, bacteremia or fever of unknown origin (FUO).

Results: A total of 28 patients aged 20 - 70 (median 35) years were enrolled and evaluable. The underlying disease included acute leukemia (68.0%), MDS (3.5%), NHL (25.0%) and others (3.5%). The median neutrophil count at study enrollment was 50/μl (range 0 to 636). In four patients found to have bacteremia, all had a positive ISH [100%] and two had a positive PCT test [50%]. In 8 patients diagnosed as local infection, one had a positive ISH [12%] and two had a positive PCT [25%]. In 16 patients with FUO, five had a positive ISH [31%] and all had a negative PCT [0%]. In 24 patients with negative blood cultures, six had a positive ISH [25%] and two had a positive PCT [8%]. In nine patients whose ISH test was positive at the onset of fever, four became negative with neutrophil recovery [44%] and other two finally became negative on resolution of the fever [22%]

Conclusion: The new ISH method may be more sensitive than blood cultures in detecting bacterial etiologies of FN.

Mizuki Aimoto1, Hideo Koh1, Akio Matsuhisa2, Shin-Ichi Inoue2, Takako Katayama1, Joji Nagasaki1, Manami Sakabe1, Hiroshi Okamura1, Takuro Yoshimura1, Akiko Inaba1, Shiro Koh1, Satoru Nanno1, Mitsutaka Nishimoto1, Yasuhiro Nakashima1, Asao Hirose1, Mika Nakamae1, Kiyoyuki Hagihara1, Yoshiki Terada1, Takahiko Nakane1, Hirohisa Nakamae1 and Masayuki Hino1, (1)Hematology, Graduate School of Medicine, Osaka City University, Osaka, Japan, (2)Research and Development Center, Fuso Pharmaceutical Industries, Ltd., Osaka, Japan

Disclosures:

M. Aimoto, None

H. Koh, None

A. Matsuhisa, None

S. I. Inoue, None

T. Katayama, None

J. Nagasaki, None

M. Sakabe, None

H. Okamura, None

T. Yoshimura, None

A. Inaba, None

S. Koh, None

S. Nanno, None

M. Nishimoto, None

Y. Nakashima, None

A. Hirose, None

M. Nakamae, None

K. Hagihara, None

Y. Terada, None

T. Nakane, None

H. Nakamae, None

M. Hino, None

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