Relationship between blaSHV-12 and blaSHV-2a in Korea.
In contrast to the USA and Europe, where SHV-2, SHV-4 and SHV-5 are the prevalent extended-spectrum SHV enzymes, in Korea SHV-2a and SHV-12 are the most frequently identified extended-spectrum SHV enzymes. A 6.6 kb BamHI fragment containing the bla(SHV-12) gene of strain K7746 isolated from one university hospital in Korea was cloned into the pCRScriptCAM vector. Sequencing of the constructed recombinant plasmid pK7746-C1 revealed that the immediate upstream sequence of the bla(SHV-12) gene showed little similarity to the part of the prototype bla(SHV-1) gene due to the insertion of an IS26 element next to the -10 region. Instead, the upstream sequences of bla(SHV-12) retained 100% DNA identity with the part of plasmid pMPA2a from Klebsiella pneumoniae KPZU-3 carrying bla(SHV-2a). The restriction map of the inserted 6.6 kb DNA fragment of plasmid pK7746-C1 was also homologous to that of plasmid pMPA2a, suggesting a common lineage of bla(SHV-12) and bla(SHV-2a). We also studied, using PCR, the upstream non-coding region of several SHV beta-lactamase genes for the presence of IS26 sequence. The flanking IS26 sequence in the immediate upstream region of the bla(SHV) gene was not detected in five standard strains producing SHV-1, SHV-2, SHV-3, SHV-4 or SHV-5. However, IS26 was detected in all 69 clinical strains producing SHV-2a or SHV-12 isolated from three university hospitals in Korea during 1993-1999. The above findings suggest a direct evolution of SHV-12 from SHV-2a, not from SHV-2 to -5, and it is considered to be one of the reasons for the absolute predominance of SHV-2a and SHV-12 in Korea.
Kim
Jungmin
J
Department of Microbiology, College of Medicine, Dankook University, Cheonan, South Korea.
Shin
Haeng-Seop
HS
Seol
Sung-Yong
SY
Cho
Dong-Taek
DT
D001483:Base Sequence / Q000235:genetics; D003428:Cross Infection / Q000201:enzymology / Q000453:epidemiology / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D019143:Evolution, Molecular; D006801:Humans; D007710:Klebsiella Infections / Q000201:enzymology / Q000453:epidemiology / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology / Q000302:isolation & purification; D007723:Korea / Q000453:epidemiology; D008969:Molecular Sequence Data; D001618:beta-Lactamases / Q000187:drug effects / Q000235:genetics*
C107198:beta-lactamase SHV-12; C062760:beta-lactamase SHV-2; D001618:beta-Lactamases