1266. Enterobacter bacteremia: Comparison of the microbiological and clinical features between Enterobacter aerogenes and Enterobacter cloacae
Session: Poster Abstract Session: Bacteremia and Endocarditis
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C
Background: Enterobacter aerogenes and Enterobacter cloacae are the two most common Enterobacter species. Nevertheless, only one report has compared the microbiological and clinical features between these two species. We aimed to examine the differences between E. aerogenes and E. cloacae bacteremia in Japan.

Methods: Between January 2008 and March 2013, we retrospectively reviewed the medical records of patients with E. aerogenes and E. cloacae bacteremia in Toranomon Hospital located at Tokyo (890 beds) and Kanagawa (300 beds) in Japan. Identification of Enterobacter species was conducted with MicroScan WalkAway96 SI systems.

Results: During the study period, we identified 36 episodes of E. aerogenes bacteremia and 94 episodes of E. cloacae bacteremia. Solid tumors or hematological malignancies were the most common underlying diseases in both groups and the details were as follows: 20 episodes of E. aerogenes bacteremia (Solid tumors:  17 episodes; hematologic malignancies: 3 episodes) and 57 episodes of E. cloacae bacteremia (Solid tumors: 39 episodes; hematologic malignancies: 18 episodes). No significant differences in age, sex, systemic steroid use, immunosuppressive drug use, and neutropenia were observed between the two groups. The rate of septic shock was significantly higher in E. cloacae bacteremia than in E. aerogenes bacteremia (43.6% vs. 22.2 %, p = .03). The overall 7-day mortality rate caused by E. cloacae bacteremia was higher than that of E. aerogenes bacteremia (8.5% vs. 0%, p = .07), although no differences in the overall 14-day (12.3% vs. 5.6%, p = .23) and 30-day mortality (21.3% vs. 16.7%, p = .49) were observed.

Conclusion: To our knowledge, this is the most comprehensive report describing the differences between the two major Enterobacter species in Japan. Initial presentation with septic shock was significantly higher in E. cloacae bacteremia, which was associated with early mortality after infection.

Masahiro Abe, MD, Muneyoshi Kimura, MD, Hideki Araoka, MD and Akiko Yoneyama, MD, Department of Infectious Diseases, Toranomon Hospital, Tokyo, Japan

Disclosures:

M. Abe, None

M. Kimura, None

H. Araoka, None

A. Yoneyama, None

Findings in the abstracts are embargoed until 12:01 a.m. PST, Oct. 2nd with the exception of research findings presented at the IDWeek press conferences.