C2-3863. Two Distinct Clones of Carbapenem-Resistant Acinetobacter baumannii Isolates from Korean Hospitals
Session: Poster Session: Acinetobacter: Global Impact
Tuesday, October 28, 2008: 12:00 AM
Room: Hall C
Background: In Korea, imipenem resistance in Acinetobacter spp. increased from 1% in 1997 to 17% in 2004.
Methods: We investigated the characteristics of 48 carbapenem-resistant Acinetobacter baumannii isolates collected from five tertiary care hospitals in Korea by multilocus sequencing typing (MLST) and PCR amplification of the antimicrobial resistance determinants.
Results: We identified two distinct main clones of carbapenem-resistant A. baumannii isolates, which showed different antimicrobial resistance profiles and are also differentiated by the kinds of OXA carbapenemases and ADC β-lactamases. One main clone, ST22, had 27 carbapenem-resistant isolates (56.3%), showed high polymyxin B and colistin resistances (33.3% and 37.0%, respectively), and contained both blaOXA51-like and blaOXA-23-like genes and the blaADC-29 or blaADC-30 gene. In contrast, the other main clone, ST28, included 15 isolates (31.3%), showed complete susceptibilities to polymyxin B and colistin, and contained only the blaOXA51-like gene and blaADC-31 or blaADC-32 genes.
Conclusions: The distribution of these two main carbapenem-resistant A. baumannii clones did not relate to locality, indicating that they are widespread in Korean hospitals. These clones showed distinct antimicrobial resistances in polymyxins, OXA carbapenemase, and ADC β-lactamase. In addition, we found new types of PER β-lactamases.
Doo Chung1, Hae Cheong2, Harim Lee, MS3, Jae Song4, Ji Choi5, Jin Baek3, Kwan Ko6, Kyong Peck, MD7, Young Park5 and  K. S. Ko, None., (1)Samsung Medical Center, Sungkyunkwan University School of Medecine, (2)Samsung Medical Center, (3)ARFID, (4)Myongji University, (5)Sungkyunkwan University School of Medecine, (6)Sungkyunkwan University School of Medecine, Suwon, Korea, Republic of, (7)Samsung Medical Center, SungKyunKwan University Medical School, Seoul, Korea, Republic of

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