Ann Lab Med.  2012 Sep;32(5):324-330. 10.3343/alm.2012.32.5.324.

AbaR7, a Genomic Resistance Island Found in Multidrug-resistant Acinetobacter baumannii Isolates in Daejeon, Korea

• Sung JY
• Koo SH
• Cho HH
• Kwon KC

• KMID: 1387346
• DOI: http://doi.org/10.3343/alm.2012.32.5.324

Abstract

BACKGROUND
Acinetobacter baumannii resistance islands (AbaRs) have been recently recognized as mobile genetic elements that harbor multiple resistance determinants and are associated with multidrug resistance (MDR). In the present study, we aimed to determine the AbaRs conferring multiple antimicrobial resistance and their clonal relatedness to MDR A. baumannii clinical isolates obtained from a university hospital in Daejeon, Korea.
METHODS
This study included 29 MDR A. baumannii strains isolated in Daejeon, Korea. The minimal inhibitory concentrations (MICs) were determined by Etest. A. baumannii isolates were characterized using the 2 multiplex PCR assays and multilocus sequence typing (MLST) scheme. To detect and characterize AbaRs, PCR and PCR mapping experiments were performed.
RESULTS
Twenty-seven of the 29 isolates belonged to the European (EU) clone II lineage and contained 5 sequence types (STs) (75, 92, 137, 138, and 357). In this study, ST357 was confirmed for the first time in Korea. Only 2 of the 29 isolates belonged to the EU clone I lineage, and were confirmed as ST109. These 2 isolates harbored the 22-kb AbaR7 aacC1-orfP-orfQ-aadA1 gene cassette array. In contrast, AbaR was not found in EU clone II isolates.
CONCLUSIONS
This is the first study that attempted to determine the AbaRs in MDR A. baumannii isolates in Korea. We found 2 EU clone I isolates (ST109) that harbored AbaR7.

Keyword

A. baumannii; Multidrug resistance; Multilocus sequence typing; PCR

MeSH Terms

Acinetobacter baumannii/drug effects/*isolation & purification/metabolism
Anti-Bacterial Agents/pharmacology
Bacterial Proteins/*genetics/metabolism
Drug Resistance, Multiple, Bacterial/drug effects
Humans
Microbial Sensitivity Tests
Multiplex Polymerase Chain Reaction
Republic of Korea
Sequence Analysis, DNA

Figure

• 

  Fig. 1 Schematic representation of A. baumannii resistance (AbaR) region showing the boundaries between interrupted genes. J1, J2, J3, J4, J5, and J6 represent the amplification regions used in the diagnostic PCRs. Abbreviations: AbaR, A. baumannii resistance; MARR, multiple-antibiotic resistance region.

• 

  Fig. 2 Repetitive element sequence-based (REP)-PCR patterns of multidrug-resistant A. baumannii strains. Lane M, 1-kb DNA size marker.

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  Fig. 3 Schematic representation of AbaR3 (A) and AbaR7 (B) isolated from multidrug-resistant A. baumannii strains that belonged to the EU clone I lineage. The dotted line in AbaR3 represents the deleted portion in AbaR7. The horizontal arrows indicate the orientation of gene translation. Abbreviations: AbaR, A. baumannii resistance; MARR, multiple-antibiotic resistance region.

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