217. Risk factors for multidrug resistance in nosocomial bacteremia caused by extended-spectrum ß-lactamase-producing Escherichia coli and Klebsiella pneumoniae : A Case-Control Study
Session: Poster Abstract Session: Antimicrobial Resistance: Clinical Studies
Friday, October 21, 2011
Room: Poster Hall B1
Background: The increasing prevalence of infections caused by extended-spectrum ß-lactamase-producing Escherichia coli and Klebsiella pneumoniae (ESBL-EK) has become a growing concern, because few antibiotics are available as therapeutic options. Efforts to maintain current therapeutic options for ESBL-EK infections are essential. Thus, this study was performed to evaluate risk factors for multidrug resistance (MDR) among nosocomial bacteremia caused by ESBL-EK.

Methods: Adult patients with ESBL-EK bacteremia from January 2009 through December 2010 were identified at Samsung Medical Center (Seoul, South Korea) and analyzed in a case-control study design. MDR ESBL-EK was defined as ESBL-EK that demonstrated in vitro resistance to trimethoprime-sulfamethoxazole, fluoroquinolones (FQ) and gentamicin, and all patients with a culture positive for an MDR ESBL-EK were designated as case patients. Control patients were those patients with an ESBL-EK isolate that did not meet criteria for MDR.

 Results:Of 123 ESBL-EK isolates (74 [60.2%] E. coli and 49 [39.8%] K. pneumoniae) causing nosocomial bacteremia, 33 (26.8%) cases were due to MDR ESBL-EK and the remaining 90 (73.2%) cases were due to non-MDR ESBL-EK. No significant differences in demographic characteristics and underlying diseases were found between both groups. In a univariate analysis, the factors significantly associated with acquisition of MDR ESBL-EK were neutropenia, immunosuppressant use, tube insertion, urinary tract infection and a prior use of antibiotics, especially FQ (all P < 0.05). A multivariable analysis showed that a prior receipt of FQ (OR= 3.396, 95% CI=1.252-9.213, P=0.016), tube insertion (OR=3.381, 95% CI=1.273-8.983, P=0.015) and neutropenia (OR=3.861, 95% CI=1.426 -10.452, P=0.008) were independent risk factors for MDR ESBL-EK among nosocomial bacteremia caused by ESBL-EK.

 Conclusion: The emergence of MDR among ESBL-EK is particularly troublesome because the therapeutic options for serious infections caused by ESBL-EK are severely restricted. Our data suggest that strategies designed to reduce MDR in ESBL-EK should focus on limiting the use of FQ and minimizing invasive procedures such as tube insertion.

Subject Category: A. Antimicrobial agents and Resistance

So Yeon Park, MD1, Cheol-In Kang, MD1, Min Hee Lim, MD1,2, Hyun Ah Kim3, Eun-Jeong Joo, MD1, Young Eun Ha, MD1, Doo Ryeon Chung, MD1, Kyong Ran Peck, MD1 and Jae-Hoon Song, MD1,4, (1)Division of Infectious Diseases, Samsung Medical Center, Seoul, South Korea, (2)Internal Medicine, Gyeongsang National University School of Medicine, Jinju, South Korea, (3)Samsung medical center, seoul, South Korea, (4)ARFID, Seoul, Korea, Republic of


S. Y. Park, None

C. I. Kang, None

M. H. Lim, None

H. A. Kim, None

E. J. Joo, None

Y. E. Ha, None

D. R. Chung, None

K. R. Peck, None

J. H. Song, None

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