Detection of genes coding for extended-spectrum SHV beta-lactamases in clinical isolates by a molecular genetic method, and comparison with the E test

Abstract

A highly sensitive and specific method, termed PCR/NheI, for the detection of genes coding for SHV extended-spectrum β-lactamases (ESBL) in clinical isolates is presented. It is based on polymerase chain reaction (PCR) amplification of thebla _SHV genes, followed by restriction withNheI. Due to the glycine (position 238) (SHV-non-ESBL) → serine (position 238) (SHV-ESBL) mutation, only PCR fragments from the genes coding for SHV-ESBLs were cleaved. A commercially available test for ESBLs, the E test ESBL, identified 52% of our 29 clinical isolates carryingbla _SHV-ESBL genes as ESBL producers.