Detection of the Carbapenem Resistance Gene in Gram-negative Rod Bacteria Isolated from Clinical Specimens

Abstract

Carbapenem-resistant Enterobacteriaceae (CRE) poses an increasing public health threat and has limited treatment options with high associated mortality. Genotypes of carbapenemase that threaten public health (blaKPC, blaNDM, blaIMP, and blaVIM) and blaOXA-48-like genes were detected by phenotypic and molecular diagnosis, and related gene distribution patterns were investigated. Phenotypic testing using the modified Hodge test confirmed positivity in all 41 strains examined, and carbapenemase inhibitory testing using meropenem+phenyl boronic acid or meropenem+EDTA confirmed positivity in 18 and 8 strains, respectively. Polymerase chain reaction revealed the presence of amplification products in 28 strains of blaKPC, 25 strains of blaNDM, 5 strains of blaIMP, 1 strain of blaVIM, and 13 blaOXA-48-like strains. In addition, 7 strains of blaKPC+blaNDM, 1 strain of blaKPC+blaIMP, 1 strain of blaNDM+blaOXA-48-like, 1 strain of blaNDM+blaVIM, 4 strains of blaKPC+blaNDM+blaIMP, and 4 strains of blaKPC+blaNDM+blaOXA-48-like were identified. Melting curve analysis using real-time PCR was wholly consistent with PCR results. The study shows genetic identification of highly specific CRE by real-time PCR could be used to provide early diagnoses and infection control, improve surveillance, and prevent the transmission of CRE.

Keywords

• blakpc
• blandm
• blaimp
• blavim
• blaoxa-48-like
• real-time pcr