514. Risk Factors for Acquisition of Trimethoprim-sulfamethoxazole Resistant Stenotrophomonas maltophilia: A Case-Control Study
Session: Poster Session: Hospital-acquired and Transplant Infections
Friday, October 30, 2009: 12:00 AM
Room: Poster Hall A
Background: Although trimethoprim-sufamethoxazole (TMP-SMX) has been considered a drug of choice to treat infections caused by Stenotrophomonas maltophilia (S. maltophilia), the TMP/SMX resistance rate among S. maltophilia isolates has been increasing for the last decade. Thus, this study was performed to identify risk factors for the acquisition of TMP-SMX-resistant S. maltophilia.
Methods: Among 554 patients with S. maltophilia infection or colonization from April 2007 to March 2009, 57 (10.3%) had TMP/SMX-resistant isolates and thus were classified as the case group. The data of 57 cases were compared with 57 controls consisting of patients with TMP-SMX-susceptible isolates. The control was matched according to patient age and acquisition unit.
Results: There were no significant differences in demographic characteristics. In an univariate analysis, the factors significantly associated with acquisition of TMP-SMX-resistant S. maltophilia were immunosuppressant use, previous history of surgery within 3 months, longer hospital stay, mechanical ventilation, prior isolation of S. maltophilia within 3 months, and prior use of fluoroquinolones, broad-spectrum cephalosporins or TMP/SMX within 3 months (All P < 0.05). Among these, prior S. maltophilia isolation (OR=12.78, 95% CI=3.17-51.57, P<0.001), prior use of TMP/SMX (OR=22.91, 95% CI=2.73-192.50, P=0.004), and prior use of broad-spectrum cephalosporins (OR=2.83, 95% CI=1.11-7.19, P=0.029) were found to be independent risk factors associated with acquisition of TMP-SMX-resistant S. maltophilia.
Conclusion: Our data suggest that strategies designed to reduce the TMP/SMX resistance rate in S. maltophilia isolates should focus on limiting the use of TMP/SMX and broad-spectrum cephalosporins, especially in patients with previous history of S. maltophilia infection or colonization.
Doo Ryun Chung, MD PhD1, Mi-kyong Joung, MD1, Cheol-In Kang, MD1, Jeong-a Lee, MD1, NamYong Lee, MD PhD1, Soo-youn Moon, MD, fellow1, Kyong Ran Peck, MD, PhD, Kyung Mok Sohn, MD, fellow1, Jae-Hoon Song, MD3 and  J. Lee, None..
M. Joung, None..
S. Moon, None..
K. Sohn, None..
C. Kang, None..
D. Chung, None..
N. Lee, None..
K. Peck, None..
J. Song, None., (1)Samsung Medical Center, Seoul, Korea, Republic of, (2)Division of Infectious Diseases, Samsung Medical Center, Seoul, South Korea