187. Increase of breakthrough bacteremia along with excessive use of carbapenems in HSCT recipients
Session: Poster Abstract Session: Antimicrobial Stewardship: Current State and Future Opportunities
Thursday, October 8, 2015
Room: Poster Hall

Background: Hematopoietic Stem Cell Transplantation(HSCT) recipients sometimes experience febrile neutropenia (FN) and need broadspectrum antibiotics. In the empirical treatment of FN, we usually choose cefepime or a carbapenem. In our facility, the chance of selecting a carbapenem for the treatment has increased with the increasing isolation rate of ESBL producing Enterobacteriaceae (ESBLs) in the preceding active surveillance culture. In spite of these empiric treatments, we sometimes experience the breakthrough bacteremia with resistant organisms. The object of this study is to determine the clinical significance of carbapenem use on breakthrough bacteremia in HSCT recipients.

Methods: A total of 266 HSCTs were performed from 2009 through 2013 at HSCT ward in Kyushu University Hospital, Japan. Retrospective analysis from a collected database was conducted. Medical charts from 14 days before transplantation until engraftment were examined. Incidence of breakthrough bacteremia (carbapenem resistant gram negative bacteremia and fungemia) and isolation rate of carbapenem resistant bacteria in surveillance cultures were compared between the representative period of 2010 and 2013.

Results: The total numbers of allogeneic HSCTs in 2010 and 2013 are 48 and 34, respectively (Table 1). The days of therapy(DOTs) per 1000 patients-days of carbapenems  increased from 188.8 in 2010 to 366.2 in 2013(p=0.0007), together with the increase in the rate of carriers with ESBLs from 6.3% to 35.3%. Compared to 2010, the rate of recipients with breakthrough bacteremia increased significantly in 2013(2.1% vs 14.7%, P=0.031) ( Table 2). The total numbers of surveillance cultures were 1,343 in 2010 and 1,380 in 2013. The isolation rate of Stenotrophomonas maltophilia increased from 16.7% in 2010 to 41.2% in 2013, significantly, while that of carbapenem resistant Pseudomonas aeruginosa did not.

Conclusion: With the increased consumption of carbapenems, breakthrough bacteremia and the isolation of S. maltophila increased. In view of avoiding breakthrough bacteremia with resistant organisms, we should make more efforts in appropriate use of antimicrobials by implementation of antimicrobial stewardship.

Ruriko Nishida, MD1,2, Makiko Kiyosuke, ICMT2,3, Koji Kato, MD, PhD1 and Nobuyuki Shimono, MD, PhD1,3, (1)Dep. Medicine and Biosystemic Science, Kyushu University Graduate School of Medical Science, Fukuoka, Japan, (2)Dep. Clinical Chemistry and Laboratory Medicine, Kyushu University Hospital, Fukuoka, Japan, (3)Ctr. for the study of Global Infection, Kyushu University Hospital, Fukuoka, Japan

Disclosures:

R. Nishida, None

M. Kiyosuke, None

K. Kato, None

N. Shimono, None

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