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Relationship between blaSHV-12 and blaSHV-2a in Korea
Jungmin Kim1, Haeng-Seop Shin, Sung-Yong Seol
1Department of Microbiology, College of Medicine, Dankook University, Cheonan, South Korea.
The Journal of Antimicrobial Chemotherapy
|January 30, 2002
Summary
In Korea, SHV-2a and SHV-12 are dominant extended-spectrum beta-lactamase enzymes. This study suggests SHV-12 evolved directly from SHV-2a, explaining their prevalence due to IS26 insertion.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Extended-spectrum beta-lactamase (ESBL) enzymes, particularly SHV types, are significant in antimicrobial resistance.
- Prevalence of SHV enzyme variants differs geographically, with SHV-2a and SHV-12 being dominant in Korea.
Purpose of the Study:
- To investigate the genetic basis for the predominance of SHV-2a and SHV-12 in Korea.
- To determine the evolutionary relationship between SHV-12 and other SHV beta-lactamase variants.
Main Methods:
- Cloning and sequencing of the bla(SHV-12) gene from a Korean clinical isolate.
- Comparative sequence analysis of upstream regions of bla(SHV) genes.
- Polymerase Chain Reaction (PCR) to detect IS26 insertion elements.
Main Results:
- The bla(SHV-12) gene in strain K7746 contained an IS26 insertion element upstream, unlike bla(SHV-1).
- The upstream sequence of bla(SHV-12) showed high identity to that of bla(SHV-2a) on plasmid pMPA2a.
- IS26 was detected in the upstream region of all 69 Korean clinical strains producing SHV-2a or SHV-12, but not in strains producing SHV-1 to SHV-5.
Conclusions:
- SHV-12 likely evolved directly from SHV-2a through IS26 insertion.
- This evolutionary pathway explains the widespread prevalence of SHV-2a and SHV-12 in Korean hospitals.